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Sample records for aisi 304l stainless

  1. Preparation of high-performance ultrafine-grained AISI 304L stainless steel under high temperature and pressure

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    Peng Wang

    2016-08-01

    Full Text Available Bulk ultra-fine grained (UFG AISI 304L stainless steel with excellent mechanical properties was prepared by a high-temperature and high-pressure (HTHP method using nanocrystalline AISI 304L stainless steel powders obtained from ball milling. Samples were sintered in high-pressure conditions using the highest martensite content of AISI 304L stainless steel powders milled for 25 h. Analyses of phase composition and grain size were accomplished by X-ray diffraction and Rietveld refinement. By comparing the reverse martensite transformation under vacuum and HTHP treat, we consider that pressure can effectively promote the change in the process of transformation. Compared with the solid-solution-treated 304L, the hardness and yield strength of the samples sintered under HTHP are considerably higher. This method of preparation of UFG bulk stainless steel may be widely popularised and used to obtain UFG metallic materials with good comprehensive performance.

  2. Biaxial fatigue tests of notched specimens for AISI 304L stainless steel

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    G. Beretta

    2016-07-01

    Full Text Available High cycle fatigue tests were conducted for stainless steel AISI 304L. The geometry was a thin walled tube with a passing through hole. The tests were axial, torsional and in-phase axial-torsional, all of them under load control with R = −1. The S-N curves were constructed following the ASTM E739 standard and the fatigues limits were calculated following the method of maximum likelihood proposed by Bettinelli. The crack direction along the surface was analysed, with especial attention to the crack initiation zones. The notch fatigue limits for different hole diameters were compared with the predictions done with a microstructural fracture mechanics model.

  3. Martensitic Transformation in Ultrafine-Grained Stainless Steel AISI 304L Under Monotonic and Cyclic Loading

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    Heinz Werner Höppel

    2012-02-01

    Full Text Available The monotonic and cyclic deformation behavior of ultrafine-grained metastable austenitic steel AISI 304L, produced by severe plastic deformation, was investigated. Under monotonic loading, the martensitic phase transformation in the ultrafine-grained state is strongly favored. Under cyclic loading, the martensitic transformation behavior is similar to the coarse-grained condition, but the cyclic stress response is three times larger for the ultrafine-grained condition.

  4. Cladding of aluminum on AISI 304L stainless steel by cold roll bonding: Mechanism, microstructure, and mechanical properties

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    Akramifard, H.R., E-mail: akrami.1367@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Mirzadeh, H., E-mail: hmirzadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Parsa, M.H., E-mail: mhparsa@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-09-08

    The AA1050 aluminum alloy and AISI 304L stainless steel sheets were stacked together to fabricate Al/304L/Al clad sheet composites by the cold roll bonding process, which was performed at temperatures of ∼100 and 23 °C to produce austenitic and austenitic–martensitic microstructures in the AISI 304L counterpart, respectively. The peel test results showed that the threshold reduction required to make a suitable bond at room temperature is below 10%, which is significantly lower than the required reduction for cold roll bonding of Al sheets. The tearing of the Al sheet during the peel test signified that the bond strength of the roll bonded sheets by only 38% reduction has reached the strength of Al, which is a key advantage of the developed sheets. The extrusion of Al through the surface cracks and settling inside the 304L surface valleys due to strong affinity between Al and Fe was found to be the bonding mechanism. Subsequently, the interface and tensile behaviors of three-layered clad sheets after soaking at 200–600 °C for 1 h were investigated to characterize the effect of annealing treatment on the formation and thickening of intermetallic compound layer and the resultant mechanical properties. Field emission scanning electron microscopy, X-ray diffraction, and optical microscopy techniques revealed that an intermediate layer composed mainly of Al{sub 13}Fe{sub 4}, FeC and Al{sub 8}SiC{sub 7} forms during annealing at 500–600 °C. A significant drop in tensile stress–strain curves after the maximum point (UTS) was correlated to the interface debonding. It was found that the formation of intermediate layer by post heat treatment deteriorates the bond quality and encourages the debonding process. Moreover, the existence of strain-induced martensite in clad sheets was found to play a key role in the enhancement of tensile strength.

  5. Impedance investigation of thermally formed oxide films on AISI 304L stainless steel

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    Hamadou, L. [Laboratoire de Materiaux, Electrochimie et Corrosion, Universite Mouloud Mammeri de Tizi-Ouzou, B.P. 17, Tizi-Ouzou 15000 (Algeria)], E-mail: lamhama@yahoo.fr; Kadri, A.; Benbrahim, N. [Laboratoire de Materiaux, Electrochimie et Corrosion, Universite Mouloud Mammeri de Tizi-Ouzou, B.P. 17, Tizi-Ouzou 15000 (Algeria)

    2010-03-15

    Thin oxide layers on 304L stainless steel were grown by thermal oxidation at 300 deg. C at different durations ranging from 2 to 4 h. The structural characterization of the oxide films was carried out by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrochemical impedance spectroscopy was used to investigate the effects of exposure time and applied potential on the electronic properties of these films. Oxide films are described by a multilayer structure, with n-type iron oxide and oxyhydroxide in the outer layers and p-type chromium oxide in the inner layer. Doping densities evaluated from Mott-Schottky plots increased with the oxidation duration, with characteristics of highly disordered semiconductor.

  6. The role of martensitic transformation on bimodal grain structure in ultrafine grained AISI 304L stainless steel

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    Sabooni, S., E-mail: s.sabooni@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of); Karimzadeh, F.; Enayati, M.H. [Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of); Ngan, A.H.W. [Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2015-06-11

    In the present study, metastable AISI 304L austenitic stainless steel samples were subjected to different cold rolling reductions from 70% to 93%, followed by annealing at 700 °C for 300 min to form ultrafine grained (UFG) austenite with different grain structures. Transmission electron microscopy (TEM) and nanoindentation were used to characterize the martensitic transformation, in order to relate it to the bimodal distribution of the austenite grain size after subsequent annealing. The results showed that the martensite morphology changed from lath type in the 60% rolled sample to a mixture of lath and dislocation-cell types in the higher rolling reductions. Calculation of the Gibbs free energy change during the reversion treatment showed that the reversion mechanism is shear controlled at the annealing temperature and so the morphology of the reverted austenite is completely dependent on the morphology of the deformation induced martensite. It was found that the austenite had a bimodal grain size distribution in the 80% rolled and annealed state and this is related to the existence of different types of martensite. Increasing the rolling reduction to 93% followed by annealing caused changing of the grain structure to a monomodal like structure, which was mostly covered with small grains of around 300 nm. The existence of bimodal austenite grain size in the 80% rolled and annealed 304L stainless steel led to the improvement of ductility while maintaining a high tensile strength in comparison with the 93% rolled and annealed sample.

  7. Plasma nitriding of AISI 304L and AISI 316L stainless steels: effect of time in the formation of S phase and the chromium nitrides; Nitretacao a plasma dos acos inoxidaveis AISI 304L e AISI 316L: efeito do tempo na formacao da fase S e dos nitretos de cromo

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    Souza, D.A. de; Barbosa, G.C.; Pinto, F.A.M.; Gontijo, L.C. [Instituto Federal de Educacao, Ciencia e Tecnologia do Espirito Santo - IFES, Vitoria, ES (Brazil); Canal, G.P.; Cunha, A.G., E-mail: disouzam@yahoo.com.br [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil). Dept. de Fisica

    2009-07-01

    Plasma nitriding can improve hardness and wear resistance of austenitic stainless steels without losses in corrosion resistance. This fact relies on a nitrided layer constituted only by S phase, without chromium nitrides precipitation. In this work, the effect of nitriding time on phases formed on nitrided layer was investigated in two austenitic stainless steels: AISI 304L e AISI 316L. The samples were nitrided at 420 deg C, using a mixture of 60 % N{sub 2} and 40% H{sub 2}, during 5, 7 and 9 hours. It was noted that chromium nitrides were formed on samples of AISI 304L, nitrided for 7 e 9 hours, while all nitrided samples of AISI 316L showed only formation of S phase. The nitrided layers were characterized using optical microscope and x-ray diffraction. (author)

  8. Corrosion behaviour of nitrogen ion implanted AISI type 304L stainless steel in nitric acid medium

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    Padhy, N.; Ningshen, S. [Corrosion Science and Technology Division, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Panigrahi, B.K. [Material Science Division, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Kamachi Mudali, U. [Corrosion Science and Technology Division, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India)], E-mail: kamachi@igcar.gov.in

    2010-01-15

    The effects of nitrogen ion implantation on corrosion behaviour of 304L stainless steel in 1 N HNO{sub 3} medium were investigated using surface analytical and electrochemical techniques. Nitrogen ion was implanted at 70 keV in the dose range of 1 x 10{sup 15}, 1 x 10{sup 16}, 1 x 10{sup 17} and 2.5 x 10{sup 17} N{sup +}/cm{sup 2}, respectively. Grazing incidence X-ray diffraction results for unimplanted and up to dose of 1 x 10{sup 16} N{sup +}/cm{sup 2} showed co-existence of {gamma}-Fe and {alpha}'-Fe and, at higher doses (1 x 10{sup 17} and 2.5 x 10{sup 17}) preferential formation of chromium nitride was observed. X-ray photoelectron spectroscopy investigation confirmed the formation of chromium nitride at higher doses. Electrochemical corrosion investigation revealed nobler open circuit potential, decrease in corrosion current densities, passive current densities and increase in polarization resistance with increase in dose rate. Surface morphology analysis after polarization study using atomic force microscope showed grain boundary dissolution for unimplanted specimens and resistance to surface dissolution with increase in dose rate for implanted specimens.

  9. Martensite phase reversion-induced nano/ ultrafine grained AISI 304L stainless steel with magnificent mechanical properties

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    Mohammad Shirdel

    2015-06-01

    Full Text Available Austenitic stainless steels are extensively used in various applications requiring good corrosion resistance and formability. In the current study, the formation of nano/ ultrafine grained austenitic microstructure in a microalloyed AISI 304L stainless steel was investigated by the advanced thermomechanical process of reversion of strain-induced martensite. For this purpose, samples were subjected to heavy cold rolling to produce a nearly complete martensitic structure. Subsequently, a wide range of annealing temperatures (600 to 800°C and times (1 to 240 min were employed to assess the reversion behavior and to find the best annealing condition for the production of the nano/ultrafine grained austenitic microstructure. Microstructural characterizations have been performed using X-ray diffraction (XRD, scanning electron microscopy (SEM, and magnetic measurement, whereas the mechanical properties were assessed by tensile and hardness tests. After thermomechanical treatment, a very fine austenitic structure was obtained, which was composed of nano sized grains of ~ 85 nm in an ultrafine grained matrix with an average grain size of 480 nm. This microstructure exhibited superior mechanical properties: high tensile strength of about 1280 MPa with a desirable elongation of about 41%, which can pave the way for the application of these sheets in the automotive industry.

  10. Standard test method for electrochemical reactivation (EPR) for detecting sensitization of AISI type 304 and 304L stainless steels

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    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 This test method covers a laboratory procedure for conducting an electrochemical reactivation (EPR) test on AISI Type 304 and 304L (UNS No. S30400 and S30403, respectively) stainless steels. This test method can provide a nondestructive means of quantifying the degree of sensitization in these steels (1, 2, 3). This test method has found wide acceptance in studies of the effects of sensitization on intergranular corrosion and intergranular stress corrosion cracking behavior (see Terminology G15). The EPR technique has been successfully used to evaluate other stainless steels and nickel base alloys (4), but the test conditions and evaluation criteria used were modified in each case from those cited in this test method. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this...

  11. Physisorption of ammonia on AISI 304L stainless steel at different surface temperature under high vacuum conditions

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    A. de Castro

    2016-12-01

    Full Text Available The physisorption of ammonia molecules (sticking on the walls of a stainless steel pipe (AISI 304L has been studied at different wall temperatures (323-473K. The total amount of ammonia that is retained on the walls, once equilibrium is reached, has been measured by differentially-pumped mass spectrometry in gas exposure laboratory experiments. The results show ammonia retentions in the range of μg/cm2 resulting in a multilayer adsorption with lower amounts of stuck ammonia at higher temperatures of the stainless steel surface. The sticking coefficient follows an exponential decay evolution with time. The activation energy of the process has been estimated by an Arrhenius fit, assuming that the characteristic time for this decay is inversely proportional to the kinetic adsorption constant. A value of 0.15eV per ammonia molecule has been obtained, being in agreement with nominal values for the physisorption of small molecules or atoms (CO, N2, Ar… that can be found in the specialized literature. The implication of these results in the possible extrapolation to the ITER vacuum system under nitrogen seeded plasma operation is also addressed.

  12. Analyses of oxide films grown on AISI 304L stainless steel and Incoloy 800HT exposed to supercritical water environment

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    Fulger, Manuela, E-mail: manuela.fulger@nuclear.ro [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania); Mihalache, Maria; Ohai, Dumitru [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania); Fulger, Stefan [University Politechnica Bucharest, Splaiul Independentei Street, No. 313, Bucharest 060042 (Romania); Valeca, Serban Constantin [University of Pitesti, Targul din Vale Street, No. 1, 110040 Pitesti (Romania)

    2011-08-15

    Supercritical water (SCW) is being considered as a cooling medium for the next generation nuclear reactors because it provides high thermal efficiency and plant simplification. However, materials corrosion has been identified as a critical problem due to the oxidative nature of supercritical water. Thus, for safety using of these nuclear reactor systems a systematic study of candidate materials corrosion is needed. As in other high temperature environments, corrosion in SCW occurs by the growth of an oxide layer on the materials surface. The current work aims to evaluate oxidation behavior of AISI 304L SS and Incoloy 800HT in water at supercritical temperatures in the range 723-873 K under a pressure of 25 MPa for up to 1680 h. After exposure to deaerated supercritical water, the samples were investigated using gravimetry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). Oxide films grown on these materials have a layered structure with an outer layer consisting of a mixture of iron oxide/iron-nickel spinel oxides and an inner layer consisting of chromium oxide in the case of Incoloy 800HT and nickel-chromium spinel oxide in the case of AISI 304L SS. The mass gains for Incoloy 800HT at all temperatures were small, while comparatively with AISI 304L SS which exhibited higher oxidation rates. In the same time the results obtained by EIS indicate the best corrosion resistance of oxides grown on Incoloy 800HT surface.

  13. Crack propagation in stainless steel AISI 304L in Hydrogen Chemistry conditions (HWC); Propagacion de Grietas en Acero Inoxidable AISI 304L en Condiciones de Quimica de Hidrogeno (HWC)

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    Diaz S, A.; Fuentes C, P.; Merino C, F. [ININ, Carretera Mexico -Toluca s/n, La Marquesa, Ocoyoacac, Mexico (Mexico); Castano M, V. [Instituto de Fisica Aplicada, UNAM, Km 15.5 Carretera Queretaro-San Luis Potosi, Juriquilla, Queretaro (Mexico)]. e-mail: ads@nuclear.inin.mx

    2006-07-01

    Velocities of crack growth in samples type CT pre cracking of stainless steel AISI 304l solder and sensitized thermally its were obtained by the Rising Displacement method or of growing displacement. It was used a recirculation circuit that simulates the operation conditions of a BWR type reactor (temperature of 280 C and a pressure of 8 MPa) with the chemistry modified by the addition of hydrogen with and without the addition of impurities of a powerful oxidizer like the Cu{sup +} ion. In each essay stayed a displacement velocity was constant of 1x10{sup -9} m/s, making a continuous pursuit of the advance of the crack by the electric potential drop technique. Contrary to the idea of mitigation of the crack propagation velocity by effect of the addition of the hydrogen in the system, the values of the growth velocities obtained by this methodology went similar to the opposing ones under normal operation conditions. To the finish of the rehearsal one carries out the fractographic analysis of the propagation surfaces, which showed cracks growth in trans and intergranular way, evidencing the complexity of the regulator mechanisms of the IGSCC like in mitigation conditions as the alternative Hydrogen Chemistry. (Author)

  14. Propagation of crevices in stainless steel AISI304L in conditions of hydrogen chemistry (HWC); Propagacion de grietas en acero inoxidable AISI304L en condiciones de quimica de hidrogeno (HWC)

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    Diaz S, A.; Fuentes C, P.; Merino C, F. [ININ, 52750 Ocoyoacac, Estado de Mexico (Mexico); Castano M, V. [IFA-UNAM, Juriquilla, Queretaro (Mexico)]. e-mail: ads@nuclear.inin.mx

    2006-07-01

    Crevice growth velocities in samples of AISI 304L stainless steel thermally welded and sensitized were obtained by the Rising displacement method or of growing displacement. It was used a recirculation circuit in where the operation conditions of a BWR type reactor were simulated (temperature of 288 C and a pressure of 8 MPa) with the chemistry modified by the addition of hydrogen with and without the addition of impurities of a powerful oxidizer like the Cu{sup ++} ion. CT pre cracked specimens were used and each rehearsal stayed to one constant displacement velocity of 1 x 10{sup -9} m/s (3.6 {mu}m/hr), making a continuous pursuit of the advance of the crack by the electric potential drop technique. To the end of the rehearsal it was carried out the fractographic analysis of the propagation surfaces. The values of the growth velocities obtained by this methodology went similar to the opposing ones under normal conditions of operation; while the fractographic analysis show the cracks propagation in trans and intergranular ways, evidencing the complexity of the regulator mechanisms of the one IGSCC even under controlled ambient conditions or with mitigation methodologies like the alternative hydrogen chemistry. (Author)

  15. Characterization of welding of AISI 304l stainless steel similar to the core encircling of a BWR reactor; Caracterizacion de soldaduras de acero inoxidable AISI 304L similares a las de la envolvente del nucleo de un reactor BWR

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    Gachuz M, M.E.; Palacios P, F.; Robles P, E.F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    Plates of austenitic stainless steel AISI 304l of 0.0381 m thickness were welded by means of the SMAW process according to that recommended in the Section 9 of the ASME Code, so that it was reproduced the welding process used to assemble the encircling of the core of a BWR/5 reactor similar to that of the Laguna Verde Nucleo electric plant, there being generated the necessary documentation for the qualification of the one welding procedure and of the welder. They were characterized so much the one base metal, as the welding cord by means of metallographic techniques, scanning electron microscopy, X-ray diffraction, mechanical essays and fracture mechanics. From the obtained results it highlights the presence of an area affected by the heat of up to 1.5 mm of wide and a value of fracture tenacity (J{sub IC}) to ambient temperature for the base metal of 528 KJ/m{sup 2}, which is diminished by the presence of the welding and by the increment in the temperature of the one essay. Also it was carried out an fractographic analysis of the fracture zone generated by the tenacity essays, what evidence a ductile fracture. The experimental values of resistance and tenacity are important for the study of the structural integrity of the encircling one of the core. (Author)

  16. Influence of Size on the Microstructure and Mechanical Properties of an AISI 304L Stainless Steel—A Comparison between Bulk and Fibers

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    Francisco J. Baldenebro-Lopez

    2015-01-01

    Full Text Available In this work, the mechanical properties and microstructural features of an AISI 304L stainless steel in two presentations, bulk and fibers, were systematically studied in order to establish the relationship among microstructure, mechanical properties, manufacturing process and effect on sample size. The microstructure was analyzed by XRD, SEM and TEM techniques. The strength, Young’s modulus and elongation of the samples were determined by tensile tests, while the hardness was measured by Vickers microhardness and nanoindentation tests. The materials have been observed to possess different mechanical and microstructural properties, which are compared and discussed.

  17. Laser Rewelding of 304L Stainless Steel.

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    Maguire, Michael Christopher [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rodelas, Jeffrey [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2016-11-01

    Laser welding of 304L stainless steel during component fabrication has been found to alter the chemical composition of the steel due to material evaporation. During repair or rework, or during potential reuse/ rewelding of certain components, the potential exists to alter the composition to the extent that the material becomes prone to solidification cracking. This work aims to characterize the extent of this susceptibility in order to make informed decisions regarding rewelding practice and base metal chemistry allowances.

  18. Ferromagnetic properties of cold rolled AISI 304L steel

    Science.gov (United States)

    Tavares, S. S. M.; da Silva, M. R.; Neto, J. M.; Miraglia, S.; Fruchart, D.

    2002-04-01

    The ferromagnetic properties (coercive force, residual and saturation magnetisation) of a cold rolled AISI 304L stainless steel were measured as function of the applied deformation, using a vibrating sample magnetometer. The martensite volume fraction produced by deformation was calculated through the magnetisation saturation ( σs) value. A maximum amount of martensite (81%) was obtained by applying a true deformation ɛ=2.41 and a heat treatment at 400°C after rolling. The residual induction ( Br) and the squareness (=ratio between residual ( Br) and saturation ( Bs) inductions) increased, while the coercive field ( Hc) decreased with the amount of deformation. The heat treatment at 400°C promotes as well the increase of both Br and Br/ Bs and the decrease of Hc. The magnetic properties obtained in the most severely deformed samples ( Hc=23.08-23.63 kJ/m 3, Br=1.01-1.20 T and Bs=1.12-1.28 T) are comparable to that of some hard and semi-hard alloys used as magnets. The stability of the ferromagnetic martensite ( α') was investigated by thermomagnetic analysis. The starting ( As) and final ( Af) temperatures of the martensite phase ( α') transformation into austenite during heating were determined to As=430-440°C and Af=610-616°C.

  19. A phenomenological study of initiation and propagation of stress corrosion cracks. Application to AISI 304L stainless steel in magnesium chloride; Etude phenomenologique de l`amorcage et de la propagation de fissures de corrosion sous contraintes. Application a l`acier inoxydable Z 2CN 18.10 dans le chlorure de magnesium

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    Peyrat, C.; Raquet, O.; Helie, M.; Santarini, G. [CEA Fontenay-aux-Roses, 92 (France). Service de la Corrosion, d`Electrochimie et Chimie des Fluides

    1999-04-01

    A purely phenomenological study of Stress Corrosion Cracking (SCC) was performed using the couple AISI 304L austenitic stainless steel/boiling magnesium chloride aqueous solution. The exploitation of the morphological information (shape of the cracks and size distribution) available after constant elongation rate tests led to the apparent initiation of the cracks and to their growth rate. A law for the real initiation is proposed too and the elongation rate effect in quantitatively characterized. (authors) 8 refs.

  20. Initiation and growth of thermal fatigue crack networks in an AISI 304 L type austenitic stainless steel (X2 CrNi18-09); Amorcage et propagation de reseaux de fissures de fatigue thermique dans un acier inoxydable austenitique de type X2 CrNi18-09 (AISI 304 L)

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    Maillot, V

    2004-07-01

    We studied the behaviour of a 304 L type austenitic stainless steel submitted to thermal fatigue. Using the SPLASH equipment of CEA/SRMA we tested parallelepipedal specimens on two sides: the specimens are continuously heated by Joule effect, while two opposites faces are cyclically. cooled by a mixed spray of distilled water and compressed air. This device allows the reproduction and the study of crack networks similar to those observed in nuclear power plants, on the inner side of circuits fatigued by mixed pressurized water flows at different temperatures. The crack initiation and the network constitution at the surface were observed under different thermal conditions (Tmax = 320 deg C, {delta}T between 125 and 200 deg C). The experiment produced a stress gradient in the specimen, and due to this gradient, the in-depth growth of the cracks finally stopped. The obtained crack networks were studied quantitatively by image analysis, and different parameters were studied: at the surface during the cycling, and post mortem by step-by-step layer removal by grinding. The maximal depth obtained experimentally, 2.5 mm, is relatively coherent with the finite element modelling of the SPLASH test, in which compressive stresses appear at a depth of 2 mm. Some of the crack networks obtained by thermal fatigue were also tested in isothermal fatigue crack growth under 4-point bending, at imposed load. The mechanisms of the crack selection, and the appearance of the dominating crack are described. Compared to the propagation of a single crack, the crack networks delay the propagation, depending on the severity of the crack competition for domination. The dominating crack can be at the network periphery, in that case it is not as shielded by its neighbours as a crack located in the center of the network. It can also be a straight crack surrounded by more sinuous neighbours. Indeed, on sinuous cracks, the loading is not the same all along the crack path, leading to some

  1. Optimization of tensile strength of friction welded AISI 1040 and AISI 304L steels according to statistics analysis (ANOVA)

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    Kirik, Ihsan [Batman Univ. (Turkey); Ozdemir, Niyazi; Firat, Emrah Hanifi; Caligulu, Ugur [Firat Univ., Elazig (Turkey)

    2013-06-01

    Materials difficult to weld by fusion welding processes can be successfully welded by friction welding. The strength of the friction welded joints is extremely affected by process parameters (rotation speed, friction time, friction pressure, forging time, and forging pressure). In this study, statistical values of tensile strength were investigated in terms of rotation speed, friction time, and friction pressure on the strength behaviours of friction welded AISI 1040 and AISI 304L alloys. Then, the tensile test results were analyzed by analysis of variance (ANOVA) with a confidence level of 95 % to find out whether a statistically significant difference occurs. As a result of this study, the maximum tensile strength is very close, which that of AISI 1040 parent metal of 637 MPa to could be obtained for the joints fabricated under the welding conditions of rotation speed of 1700 rpm, friction pressure of 50 MPa, forging pressure of 100 MPa, friction time of 4 s, and forging time of 2 s. Rotation speed, friction time, and friction pressure on the friction welding of AISI 1040 and AISI 304L alloys were statistically significant regarding tensile strength test values. (orig.)

  2. Simulation of Friction Stir Processing in 304L Stainless Steel

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    Miles M.P.

    2016-01-01

    Full Text Available A major dilemma facing the nuclear industry is repair or replacement of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for weld repair, the high temperatures and thermal stresses inherent in the process enhance the growth of helium bubbles, causing intergranular cracking in the heat-affected zone (HAZ. Friction stir processing (FSP has potential as a weld repair technique for irradiated stainless steel, because it operates at much lower temperatures than fusion welding, and is therefore less likely to cause cracking in the HAZ. Numerical simulation of the FSP process in 304L stainless steel was performed using an Eulerian finite element approach. Model input required flow stresses for the large range of strain rates and temperatures inherent in the FSP process. Temperature predictions in three locations adjacent to the stir zone were accurate to within 4% of experimentally measure values. Prediction of recrystallized grain size at a location about 6mm behind the tool center was less accurate, because the empirical model employed for the prediction did not account for grain growth that occurred after deformation in the experiment was halted.

  3. Weld solidification cracking in 304 to 304L stainless steel

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    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Martinez, Raymond J [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-01-01

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found. This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GT A W showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  4. Resistance Spot Weldability of Dissimilar Materials: BH180-AISI304L Steels and BH180-IFT123 Steels

    Institute of Scientific and Technical Information of China (English)

    Fatih Hayat

    2011-01-01

    In this study, resistance spot weldability of 180 grade bake hardening steel (BH180), 7123 grade interstitial free steel (IF7123) and 304 grade austenitic stainless steel (AISI304L) with each other was investigated. In the joining process, electrode pressure and weld current were kept constant and six different weld time were chosen. Microstructure, microhardness, tensile-shear properties and fracture types of resistance spot welded joints were examined. In order to characterize the metallurgical structure of the welded joint, the microstructural profile was developed, and the relationship between mechanical properties and microstructure was determined. The change of weld time, nugget diameter, the HAZ (heat affected zone) width and the electrode immersion depth were also investigated. Welded joints were examined by SEM (scanning electron microscopy) images of fracture surface. As a result of the experiment, it was determined that with increasing weld time, tensile shear load bearing capacity (TLBC) increased with weld time up to 25 cycle and two types of tearing occurred. It was also determined that while the failure occurred from IF side at the BHIS0+IF7123 joint, it occurred from the BH180 side at the BHIS0+AISI304L joint.

  5. HYDROGEN-ASSISTED FRACTURE IN FORGED TYPE 304L AUSTENITIC STAINLESS STEEL

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R. [University of Missouri-Kansas City; Bergen, R. [Precision Metal Products; Balch, D. K. [Sandia Natl Laboratory

    2012-09-06

    Austenitic stainless steels generally have good resistance to hydrogen-assisted fracture; however, structural designs for high-pressure gaseous hydrogen are constrained by the low strength of this class of material. Forging is used to increase the low strength of austenitic stainless steels, thus improving the efficiency of structural designs. Hydrogen-assisted racture, however, depends on microstructural details associated with manufacturing. In this study, hydrogen-assisted fracture of forged type 304L austenitic stainless steel is investigated. Microstructural variation in multi-step forged 304L was achieved by forging at different rates and temperatures, and by process annealing. High internal hydrogen content in forged type 304L austenitic stainless steel is achieved by thermal precharging in gaseous hydrogen and results in as much as 50% reduction of tensile ductility.

  6. Dynamic compressive response of wrought and additive manufactured 304L stainless steels

    Directory of Open Access Journals (Sweden)

    Nishida Erik

    2015-01-01

    Full Text Available Additive manufacturing (AM technology has been developed to fabricate metal components that include complex prototype fabrication, small lot production, precision repair or feature addition, and tooling. However, the mechanical response of the AM materials is a concern to meet requirements for specific applications. Differences between AM materials as compared to wrought materials might be expected, due to possible differences in porosity (voids, grain size, and residual stress levels. When the AM materials are designed for impact applications, the dynamic mechanical properties in both compression and tension need to be fully characterized and understood for reliable designs. In this study, a 304L stainless steel was manufactured with AM technology. For comparison purposes, both the AM and wrought 304L stainless steels were dynamically characterized in compression Kolsky bar techniques. They dynamic compressive stress-strain curves were obtained and the strain rate effects were determined for both the AM and wrought 304L stainless steels. A comprehensive comparison of dynamic compressive response between the AM and wrought 304L stainless steels was performed. SAND2015-0993 C.

  7. Effect of Harmonic Microstructure on the Corrosion Behavior of SUS304L Austenitic Stainless Steel

    Science.gov (United States)

    Rai, Prabhat K.; Shekhar, S.; Nakatani, M.; Ota, M.; Vajpai, S. K.; Ameyama, K.; Mondal, K.

    2016-12-01

    Corrosion behavior of a harmonic structured SUS304L austenitic stainless steel was examined and compared with nonharmonic structured SUS304L stainless steel and conventional 304 stainless steel in 3.5 pct NaCl solution. The study was performed using linear polarization, potentiodynamic polarization, cyclic polarization, and a salt fog exposure test for 30 days. Characterization was accomplished using a scanning electron microscope, an electron probe microanalyzer, and Raman spectroscopy. Improved pitting corrosion resistance was found in the case of the harmonic structured steel as compared to that of the nonharmonic and the conventional 304 stainless steel. Harmonically distributed fine-grained structure, less porosity, and higher fraction of passive α-FeOOH are attributed to the improvement in corrosion resistance of the harmonic structured steel.

  8. TESTING OF 304L STAINLESS STEEL IN NITRIC ACID ENVIRONMENTS WITH FLUORIDES AND CHLORIDES

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.

    2010-10-04

    Impure radioactive material processed in nitric acid solutions resulted in the presence of chlorides in a dissolver fabricated from 304L stainless steel. An experimental program was conducted to study the effects of chloride in nitric acid/fluoride solutions on the corrosion of 304L stainless steel. The test variables included temperature (80, 95, and 110 C) and the concentrations of nitric acid (6, 12, and 14 M), fluoride (0.01, 0.1, and 0.2 M) and chloride (100, 350, 1000, and 2000 ppm). The impact of welding was also investigated. Results showed that the chloride concentration alone was not a dominant variable affecting the corrosion, but rather the interaction of chloride with fluoride significantly affected corrosion.

  9. Comparative study of the microbiological corrosion among an AISI 304L and an API X65; Estudio comparativo de la corrosion microbiologica entre un AISI 304L y un API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Gonzalez F, E. [ITT, Toluca, Estado de Mexico (Mexico)

    2004-07-01

    Metallic samples of AISI 304L sensitized and API X65, were subjected to the action of an inoculated media with reductive sulphate microorganisms (SBR), carrying out electrochemical evaluations by means of the techniques of Polarization Resistance (RP), Tafel extrapolation (ET) and Electrochemical Noise (RE). The generated information was complemented with the analysis and diagnostic of the present damage in the surfaces exposed in both metals. The used electrochemical techniques allow to determine the corrosion velocities associated to each system, establishing that the uniform corrosion is not affected by the effect of the microorganisms; however, electrochemical noise, evidenced the formation of stings associated to the presence of bacteria. (Author)

  10. Effect of laser surface melting in tensile properties of type 304L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Akgun, O.V.; Inal, O.T. (New Mexico Inst. of Mining and Technology, Materials and Metallurgical Engineering Dept., Socorro, NM (US)); Lovato, M.L.; Jervist, T.R. (Los Alamos National Lab., Los Alamos, NM (US))

    1992-07-15

    In previous study the authors showed laser surface melting (LSM) to increase yield strength of 304 austenitic stainless steels. A consistent increase approximately 10% was also observed in the hardness of the melted layer compared to that of the substrate. Austentic stainless steels do not transform to martensite during laser processing. The microstructure is observed to contain only austenite and some retained {delta}-ferrite due to rapid cooling. Therefore, the hardness increase observed was interpreted to be due to microstructural modifications, namely in the formation of austenite {delta}-ferrite duplex structure as well as a refinement in the subgrain structure. The alloy used in this study, type 304L, is a lower carbon modification of type 304 for welding applications. Lower carbon content minimizes carbide precipitation in the heat affected zone of welds. In an annealed condition type 304L has lower mechanical properties than type 304. This paper reports on this present study which was undertaken to verify if a material that possesses an initially high yield strength, type 304L, would exhibit a similar increase in its yield strength and the magnitude of this enhancement at different test temperatures (22, 100, 200 and 300{degrees}C).

  11. Comparative Shock Response of Additively Manufactured Versus Conventionally Wrought 304L Stainless Steel*

    Science.gov (United States)

    Wise, J. L.; Adams, D. P.; Nishida, E. E.; Song, B.; Maguire, M. C.; Carroll, J.; Reedlunn, B.; Bishop, J. E.

    2015-06-01

    Gas-gun experiments have probed the compression and release behavior of impact-loaded 304L stainless steel specimens machined from additively manufactured (AM) blocks as well as baseline ingot-derived bar stock. The AM technology allows direct fabrication of metal parts. For the present study, a velocity interferometer (VISAR) measured the time-resolved motion of samples subjected to one-dimensional (i.e., uniaxial strain) shock compression to peak stresses ranging from 0.2 to 7.5 GPa. The acquired wave-profile data have been analyzed to determine the comparative Hugoniot Elastic Limit (HEL), Hugoniot equation of state, spall strength, and high-pressure yield strength of the AM and conventional materials. Observed differences in shock loading and unloading characteristics for the two 304L source variants have been correlated to complementary Kolsky bar results for compressive and tensile testing at lower strain rates. The effects of composition, porosity, microstructure (e.g., grain size and morphology), residual stress, and sample axis orientation relative to the additive manufacturing deposition trajectory have been assessed to explain differences between the AM and baseline 304L dynamic mechanical properties. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  12. Corrosion testing of type 304L stainless steel in tuff groundwater environments

    Energy Technology Data Exchange (ETDEWEB)

    Westerman, R.E.; Pitman, S.G.; Haberman, J.H.

    1987-11-01

    The stress-corrosion cracking (SCC) resistance of Type 304L stainless steel (SS) to elevated temperatures in tuff rock and tuff groundwater environments was determined under irradiated and nonirradiated conditions using U-bend specimens and slow-strain-rate tests. The steel was tested both in the solution-annealed condition and after sensitization heat treatments. The material was found to be susceptible to SCC in both the solution-annealed and solution-annealed-and-sensitized conditions when exposed to an irradiated crushed tuff rock environment containing air and water vapor at 90{sup 0}C. A similar exposure at 50{sup 0}C did not result in failure after a 25-month test duration. Specimens of sensitized 304 SS conditioned with a variety of sensitization heat treatments resisted failure during a test of 1-year duration in which a nonirradiated environment of tuff rock and groundwater held at 200{sup 0}C was allowed to boil to dryness on a cyclical basis. All specimens of sensitized 304 SS exposed to this environment failed. Slow-strain-rate studies were performed on 304L, 304, and 316L SS specimens. The 304L SS was tested in J-13 well water at 150{sup 0}C, and the 316L SS at 95{sup 0}C. Neither material showed evidence of SCC in these tests. Sensitized 304 SS did exhibit SCC in J-13 well water in tests conducted at 150{sup 0}C. 12 refs., 27 figs., 13 tabs.

  13. Comparison of SCC Behavior of 304L Stainless Steels With and Without Boron Addition in Acidic Chloride Environment

    Science.gov (United States)

    Sivai Bharasi, N.; Pujar, M. G.; Nirmal, S.; Mallika, C.; Kamachi Mudali, U.; Angelo, P. C.

    2016-07-01

    The stress corrosion cracking (SCC) behavior of 304L B4 grade borated stainless steel (SS) as well as 304L SS was investigated by constant load and slow strain rate testing (SSRT) techniques. The microstructure, pitting, and SCC behavior of borated SS in the as-received, sensitized, and solution-annealed conditions were analyzed. Potentiodynamic anodic polarization and double loop electrochemical potentiokinetic reactivation (DLEPR) experiments were carried out to find out pitting corrosion resistance and degree of sensitization (DOS). The number of boride particles (composed of Cr, Fe, and B) were highest for the specimen solution annealed at 1423 K/2 h. Solution-annealing treatment at 1423 K/4 h was found to be beneficial in improving the corrosion resistance of borated 304L SS. Although the borated 304L SS exhibited a higher DOS, it showed improved pitting corrosion resistance compared to 304L SS. Constant load experiments revealed the time to failure to be the highest for the specimen solution annealed at 1423 K/4 h. SCC susceptibility index (Iscc) values obtained from SSRT tests were lower for solution-annealed borated 304L SS compared to the as-received and sensitized conditions. The improved SCC resistance of borated 304L SS was attributed not only to the solution-annealing treatment but also the higher stacking fault energy (SFE) value compared to 304L SS.

  14. A Study on Deformation Behavior of 304L Stainless Steel During and After Plate Rolling at Elevated Temperatures

    Science.gov (United States)

    Pourabdollah, P.; Serajzadeh, S.

    2017-02-01

    In this work, microstructural evolutions and mechanical properties of AISI 304L stainless steel were studied after rolling operations at elevated temperatures. Rolling experiments were conducted under warm and hot rolling conditions in the range of 600-1000 °C employing different reductions. Then, the developed microstructures and the mechanical properties of the steel were evaluated by means of uniaxial tensile testing, metallographic observations, and x-ray diffraction method. Besides, two-dimensional finite element analysis coupled with artificial neural network modeling was developed to assess thermo-mechanical behavior of the steel during and after rolling. The results show that inhomogeneities in strain and temperature distributions are reduced under warm rolling conditions. Static recrystallization can be operative under hot rolling conditions and relatively low reduction, i.e., reduction of 25%. However, for the case of higher reductions, the rate of recrystallization decreases considerably owing to severe temperature drop in the plate being rolled. Furthermore, the rolled plates show negative strain rate sensitivity while this phenomenon is affected by the rolling temperature.

  15. Estudo comparativo entre os aços inoxidáveis dúplex e os inoxidáveis AISI 304L/316L

    Directory of Open Access Journals (Sweden)

    Marcelo Senatore

    2007-03-01

    Full Text Available Os aços inoxidáveis dúplex ferríticos-austeníticos fazem parte de uma classe de materiais com microestrutura bifásica, composta por uma matriz ferrítica e ilhas de austenita, com frações volumétricas aproximadamente iguais dessas fases. Essa classe de materiais é caracterizada por apresentar interessante combinação de elevadas propriedades mecânicas e de resistência à corrosão e, por isso, é considerada bastante versátil. Os aços inoxidáveis dúplex são, freqüentemente, utilizados nas indústrias química e petroquímica, de papel e celulose, siderúrgicas, alimentícias e de geração de energia. O presente trabalho estabelece um comparativo entre as propriedades físicas, mecânicas e de resistência à corrosão dos aços inoxidáveis duplex e os tradicionais aços inoxidáveis austeníticos AISI 304L e 316L, largamente utilizados na indústria brasileira. Resultados de ensaios laboratoriais e dados relevantes de experiências práticas desses materiais também são apresentados.Ferritic-austenitic duplex stainless steels are part of a class of material having a two-phase microestructure, comprised of a ferritic matrix and austenitic islands, with the volumetric fractions approximately the same in these phases. This class of material is characterized by the presentation of an interesting combination of high mechanical properties and corrosion resistance and is therefore considered quite versatile. The duplex stainless steels are often used in the chemical, petrochemical, pulp & paper and food industries, as well as in steel foundaries and energy power plants. This paper shows a comparison between the physical, mechanical and corrosion resistance properties of duplex stainless steels and the traditional austenitic stainless steels 304L and 316L, largely used in the Brazilian industry. Results of laboratory tests and relevant data on practical experiments on these materials are also presented.

  16. Comparative shock response of additively manufactured versus conventionally wrought 304L stainless steel

    Science.gov (United States)

    Wise, J. L.; Adams, D. P.; Nishida, E. E.; Song, B.; Maguire, M. C.; Carroll, J.; Reedlunn, B.; Bishop, J. E.; Palmer, T. A.

    2017-01-01

    Gas-gun experiments have probed the compression and release behavior of impact-loaded 304L stainless steel specimens that were machined from additively manufactured (AM) blocks as well as baseline ingot-derived bar stock. The AM technology permits direct fabrication of net- or near-net-shape metal parts. For the present investigation, velocity interferometer (VISAR) diagnostics provided time-resolved measurements of sample response for one-dimensional (i.e., uniaxial strain) shock compression to peak stresses ranging from 0.2 to 7.0 GPa. The acquired wave-profile data have been analyzed to determine the comparative Hugoniot Elastic Limit (HEL), Hugoniot equation of state, spall strength, and high-pressure yield strength of the AM and conventional materials. The possible contributions of various factors, such as composition, porosity, microstructure (e.g., grain size and morphology), residual stress, and/or sample axis orientation relative to the additive manufacturing deposition trajectory, are considered to explain differences between the AM and baseline 304L dynamic material results.

  17. Optimization of Fusion Zone Grain Size, Hardness, and Ultimate Tensile Strength of Pulsed Current Microplasma Arc Welded AISI 304L Sheets Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Siva Prasad Kondapalli

    2014-01-01

    Full Text Available Austenitic stainless steel sheets have gathered wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance, such as metal bellows used in expansion joints in aircraft, aerospace, and petroleum industry. In case of single pass welding of thinner sections of this alloy, Pulsed Current Microplasma Arc Welding (PCMPAW was found beneficial due to its advantages over the conventional continuous current process. The quality of welded joint depends on the grain size, hardness, and ultimate tensile strength, which have to be properly controlled and optimized to ensure better economy and desirable mechanical characteristics of the weld. This paper highlights the development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to grain size, and ultimate tensile strength in PCMPAW of AISI 304L sheets. The experiments were conducted based on a five-factor, five-level central composite rotatable design matrix. A genetic algorithm (GA was developed to optimize the process parameters for achieving the desired grain size, hardness, and ultimate tensile strength.

  18. Research on General Corrosion Property of 304L and 304NG Stainless Steels in Simulated PWR Primary Water

    Institute of Scientific and Technical Information of China (English)

    PENG; De-quan; HU; Shi-lin; ZHANG; Ping-zhu; WANG; Hui

    2012-01-01

    <正>The general corrosion behaviors of 304L and 304NG grade stainless steels in simulated pressurized water reactor (PWR) primary loop were studied using still autoclave, respectively, the corrosion test lasted for 1 680 hours. The corrosion oxide films were analyzed macroscopically and microscopically. The results are shown in Figs. 1, 2.

  19. An Assessment of the Ductile Fracture Behavior of Hot Isostatically Pressed and Forged 304L Stainless Steel

    Science.gov (United States)

    Cooper, A. J.; Smith, R. J.; Sherry, A. H.

    2017-02-01

    Type 300 austenitic stainless steel manufactured by hot isostatic pressing (HIP) has recently been shown to exhibit subtly different fracture behavior from that of equivalent graded forged steel, whereby the oxygen remaining in the component after HIP manifests itself in the austenite matrix as nonmetallic oxide inclusions. These inclusions facilitate fracture by acting as nucleation sites for the initiation, growth, and coalescence of microvoids in the plastically deforming austenite matrix. Here, we perform analyses based on the Rice-Tracey (RT) void growth model, supported by instrumented Charpy and J-integral fracture toughness testing at ambient temperature, to characterize the degree of void growth ahead of both a V-notch and crack in 304L stainless steel. We show that the hot isostatically pressed (HIP'd) 304L steel exhibits a lower critical void growth at the onset of fracture than that observed in forged 304L steel, which ultimately results in HIP'd steel exhibiting lower fracture toughness at initiation and impact toughness. Although the reduction in toughness of HIP'd steel is not detrimental to its use, due to the steel's sufficiently high toughness, the study does indicate that HIP'd and forged 304L steel behave as subtly different materials at a microstructural level with respect to their fracture behavior.

  20. Development of Nanocrystalline 304L Stainless Steel by Large Strain Cold Working

    Directory of Open Access Journals (Sweden)

    Marina Odnobokova

    2015-04-01

    Full Text Available The microstructural changes leading to nanocrystalline structure development and the respective tensile properties were studied in a 304L stainless steel subjected to large strain cold rolling at ambient temperature. The cold rolling was accompanied by the development of deformation twinning and martensitic transformation. The latter readily occurred at deformation microshear bands, leading the martensite fraction to approach 0.75 at a total strain of 3. The deformation twinning followed by microshear banding and martensitic transformation promoted the development of nanocrystalline structure consisting of a uniform mixture of austenite and martensite grains with their transverse sizes of 120–150 nm. The developed nanocrystallites were characterized by high dislocation density in their interiors of about 3 × 1015 m−2 and 2 × 1015 m−2 in austenite and martensite, respectively. The development of nanocrystalline structures with high internal stresses led to significant strengthening. The yield strength increased from 220 MPa in the original hot forged state to 1600 MPa after cold rolling to a strain of 3.

  1. Full field modeling of dynamic recrystallization in a global level set framework, application to 304L stainless steel

    Directory of Open Access Journals (Sweden)

    Boulais-Sinou Romain

    2016-01-01

    Full Text Available A new full field numerical approach for the simulation of dynamic and post-dynamic recrystallization will be detailed. A level Set framework is employed to link a crystal plasticity finite element method with the modeling of recrystallization. Plasticity is calculated through the activation of slip systems and provides predictions for both SSDs and GNDs densities. These predictions control the activation and kinetics of recrystallization. All the developments are applied on 304L stainless steel.

  2. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65; Estudio comparativo de la corrosion inducida por microorganismos sulfatorreductores, en un acero inoxidable 304L sensibilizado y un acero al carbono API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)]. e-mail: ads@nuclear.inin.mx

    2004-07-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  3. State on AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    A. Fattah-alhosseini

    2011-01-01

    Full Text Available The passivity and protective nature of the passive films are essentially related to ionic and electronic transport processes, which are controlled by the optical and electronic properties of passive films. In this study, the electrochemical behavior of passive films anodically formed on AISI 304 stainless steel in sulfuric acid solution has been examined using electrochemical impedance spectroscopy. AISI 304 in sulphuric acid solution is characterized by high interfacial impedance, thereby illustrating its high corrosion resistance. Results showed that the interfacial impedance and the polarization resistance (pol initially increase with applied potential, within the low potential passive. However, at a sufficiently high potential passive (>0.4 V, the interfacial impedance and the polarization resistance decrease with increasing potential. An electrical equivalent circuit based on the impedance analysis, which describes the behavior of the passive film on stainless steel more satisfactorily than the proposed models, is presented.

  4. Effects of hydrogen water chemistry on corrosion fatigue behavior of cold-worked 304L stainless steel in simulated BWR coolant environments

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, M.F., E-mail: mfchiang@iner.gov.tw [Institute of Nuclear Energy Research, Division of Nuclear Fuels and Materials, Lungtan, Taoyuan 325, Taiwan (China); Young, M.C.; Huang, J.Y. [Institute of Nuclear Energy Research, Division of Nuclear Fuels and Materials, Lungtan, Taoyuan 325, Taiwan (China)

    2011-04-15

    Corrosion fatigue behavior of stainless steel 304L (SS304L) in a simulated BWR coolant with hydrogen injection was investigated. Hydrogen water chemistry slightly mitigated the corrosion fatigue degradation of the as-received SS304L specimens, but, on the contrary, it slightly increased the corrosion fatigue crack growth rates (CFCGRs) of the cold-worked specimens. All the CFCGR-tested specimens showed similar fracture features, except for the amounts of deposited corrosion debris. The results indicated that decreasing the oxygen concentration of water environment is not an effective measure to suppress the fatigue crack growth rate of cold-worked SS304L. The CFCGRs of the SS304L were determined by an interaction between corrosion, oxide-induced crack closure and cold work in corrosive environments. At a specific level of reduction, cold work could enhance the corrosion fatigue resistance of SS304 both in the air-saturated and HWC coolant environments.

  5. Effects of hydrogen water chemistry on corrosion fatigue behavior of cold-worked 304L stainless steel in simulated BWR coolant environments

    Science.gov (United States)

    Chiang, M. F.; Young, M. C.; Huang, J. Y.

    2011-04-01

    Corrosion fatigue behavior of stainless steel 304L (SS304L) in a simulated BWR coolant with hydrogen injection was investigated. Hydrogen water chemistry slightly mitigated the corrosion fatigue degradation of the as-received SS304L specimens, but, on the contrary, it slightly increased the corrosion fatigue crack growth rates (CFCGRs) of the cold-worked specimens. All the CFCGR-tested specimens showed similar fracture features, except for the amounts of deposited corrosion debris. The results indicated that decreasing the oxygen concentration of water environment is not an effective measure to suppress the fatigue crack growth rate of cold-worked SS304L. The CFCGRs of the SS304L were determined by an interaction between corrosion, oxide-induced crack closure and cold work in corrosive environments. At a specific level of reduction, cold work could enhance the corrosion fatigue resistance of SS304 both in the air-saturated and HWC coolant environments.

  6. Effect of SiC particle impact nano-texturing on tribological performance of 304L stainless steel

    Science.gov (United States)

    Lorenzo-Martin, C.; Ajayi, O. O.

    2014-10-01

    Topographical features on sliding contact surfaces are known to have a significant impact on friction and wear. Indeed, various forms of surface texturing are being used to improve and/or control the tribological performance of sliding surfaces. In this paper, the effect of random surface texturing produced by a mechanical impact process is studied for friction and wear behavior of 304L stainless steel (SS) under dry and marginal oil lubrication. The surface processing was applied to 304L SS flat specimens and tested under reciprocating ball-on-flat sliding contact, with a 440C stainless steel ball. Under dry contact, the impact textured surface exhibited two order of magnitude lower wear than the isotropically ground surface of the same material. After 1500 s of sliding and wearing through of the processed surface layer following occurring of scuffing, the impact textured surface underwent a transition in wear and friction behavior. Under marginal oil lubrication, however, no such transition occurred, and the wear for the impact textured surface was consistently two orders of magnitude lower than that for the ground material. Mechanisms for the tribological performance enhancement are proposed.

  7. Effects of Low Temperature on Hydrogen-Assisted Crack Growth in Forged 304L Austenitic Stainless Steel

    Science.gov (United States)

    Jackson, Heather; San Marchi, Chris; Balch, Dorian; Somerday, Brian; Michael, Joseph

    2016-08-01

    The objective of this study was to evaluate effects of low temperature on hydrogen-assisted crack propagation in forged 304L austenitic stainless steel. Fracture initiation toughness and crack-growth resistance curves were measured using fracture mechanics specimens that were thermally precharged with 140 wppm hydrogen and tested at 293 K or 223 K (20 °C or -50 °C). Fracture initiation toughness for hydrogen-precharged forgings decreased by at least 50 to 80 pct relative to non-charged forgings. With hydrogen, low-temperature fracture initiation toughness decreased by 35 to 50 pct relative to room-temperature toughness. Crack growth without hydrogen at both temperatures was microstructure-independent and indistinguishable from blunting, while with hydrogen microcracks formed by growth and coalescence of microvoids. Initiation of microvoids in the presence of hydrogen occurred where localized deformation bands intersected grain boundaries and other deformation bands. Low temperature additionally promoted fracture initiation at annealing twin boundaries in the presence of hydrogen, which competed with deformation band intersections and grain boundaries as sites of microvoid formation and fracture initiation. A common ingredient for fracture initiation was stress concentration that arose from the intersection of deformation bands with these microstructural obstacles. The localized deformation responsible for producing stress concentrations at obstacles was intensified by low temperature and hydrogen. Crack orientation and forging strength were found to have a minor effect on fracture initiation toughness of hydrogen-supersaturated 304L forgings.

  8. Comparing the Formability of AISI 304 and AISI 202 Stainless Steels

    Science.gov (United States)

    du Toit, M.; Steyn, H. G.

    2012-07-01

    The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced α' martensite. Although both grades are predicted to be susceptible to earing during deep drawing, AISI 202 displays a higher work-hardening exponent, higher average normal anisotropy, and a higher limiting drawing ratio than AISI 304. Similar cup heights were measured during Erichsen cupping tests, confirming that the two grades have very similar deep drawing properties. The results of this investigation therefore suggest that AISI 202 is a suitable alternative for AISI 304 in applications requiring good deep drawing properties.

  9. Corrosion study of stainless steel SS304L in molten molybdates

    Science.gov (United States)

    Usami, T.; Uruga, K.; Tsukada, T.; Miura, Y.; Komamine, S.; Ochi, E.

    2016-04-01

    Depending on operating conditions of the vitrification process of high-level liquid waste, molten salt mainly composed of sodium and molybdenum can be generated, and poured into stainless steel canisters. In this work, the possible reaction between the molten molybdate and stainless steel was investigated using multi-component molybdate and simple Na2MoO4 - MoO3 molybdate. In the experiments using multi-component molybdates, no significant reaction is observed between the mixed molybdates and the stainless steel specimens at 700 °C in 4 h. The reaction rate of the stainless steel with the multi-component molybdate increases in proportion to exp(-1/T). The depth of the most reacted area is about 300 μm even at 1000 °C, and was much smaller than the 6 mm thickness of the canister. In the simple Na2MoO4 - MoO3 molybdate, the reaction rate was proportional to the MoO3 concentration. The essence of the reaction is oxidation of metals by Mo6+ - > Mo4+. Part of the reaction product mainly composed of Fe is dissolved into the molybdate, while the other part mainly composed of Cr sloughs and forms a banded layer.

  10. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950`s are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  11. Reactor Materials Program: Mechanical properties of irradiated Types 304 and 304L stainless steel weldment components

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.L.; Caskey, G.R. Jr.

    1991-12-01

    The vessels (reactor tanks) of the Savannah River Site nuclear production reactors constructed in the 1950's are comprised of Type 304 stainless steel with Type 308 stainless steel weld filler. Irradiation exposure to the reactor tank sidewalls through reactor operation has caused a change in the mechanical properties of these materials. A database of as-irradiated mechanical properties for site-specific materials and irradiation conditions has been produced for reactor tank structural analyses and to quantify the effects of radiation-induced materials degradation for evaluating reactor service life. The data has been collected from the SRL Reactor Materials Program (RMP) irradiations and testing of archival stainless steel weldment components and from previous SRL programs to measure properties of irradiated reactor Thermal Shield weldments and reactor tank (R-tank) sidewall material. Irradiation programs of the RMP are designed to quantify mechanical properties at tank operating temperatures following irradiation to present and future tank wall maximum exposure conditions. The exposure conditions are characterized in terms of fast neutron fluence (E{sub n} > 0.1 MeV) and displacements per atom (dpa){sup 3}. Tensile properties, Charpy-V notch toughness, and elastic-plastic fracture toughness were measured for base, weld, and weld heat-affected zone (HAZ) weldment components from archival piping specimens following a Screening Irradiation in the University of Buffalo Reactor (UBR) and following a Full-Term Irradiation in the High Flux Isotope Reactor (HFIR).

  12. Formation of abrasion-resistant coatings of the AlSiFe{sub x}Mny intermetallic compound type on the AISI 304L alloy

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Peralez, L. G.; Flores-Valdes, A.; Salinas-Rodriguez, A.; Ochoa-Palacios, R. M.; Toscano-giles, J. A.; Torres-Torres, J.

    2016-05-01

    The α-Al{sub 9}FeMnSi and α-Al{sub 9}FeMn{sub 2}Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 degree centigrade), pressure (5, 10 y 20 MPa) and holding time (3600, 5400 y 7200 seconds). Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 degree centigrade, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of β-Al{sub 9}FeMnSi and β-Al{sub 9}FeMn{sub 2}Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface. (Author)

  13. Microestrutura de uma Solda Dissimilar entre o Aço Inoxidável Ferrítico AISI 410S e o Aço Inoxidável Austenítico AISI 304L Soldado pelo Processo FSW

    OpenAIRE

    Tathiane Caminha Andrade; Cleiton Carvalho Silva; Hélio Cordeiro de Miranda; Marcelo Ferreira Motta; Jesualdo Pereira Farias; Luciano Andrei Bergman; Jorge Fernandes dos Santos

    2015-01-01

    Resumo O presente trabalho visa investigar a microestrutura formada na soldagem dissimilar entre chapas de aços inoxidáveis ferríticos AISI 410S e aços inoxidáveis austeníticos AISI 304L pelo processo friction stir welding. A soldagem foi realizada com o ajuste dos seguintes parâmetros: rotação 450 rpm; velocidade de soldagem de 1,0 mm/s; e força axial 40 kN. O aço AISI 410S foi posicionado no lado de avanço enquanto que o aço AISI 304L foi posicionado no lado de retrocesso. A análise consist...

  14. Acoustic wave propagation in austenitic stainless steel AISI 304L: Application examples

    Energy Technology Data Exchange (ETDEWEB)

    Dahmene, F., E-mail: fethidahmen@yahoo.fr [Laboratoire Roberval Unite Mixte 6066 CNRS, UTC, BP20592, 60205 Compiegne (France)] [Ecole des Mines de Douai, Departement Technologies des Polymeres et Composites and Ingenierie Mecanique, 941 rue Charles Bourseul, BP. 10838, 59508 Douai Cedex (France); Laksimi, A. [Laboratoire Roberval Unite Mixte 6066 CNRS, UTC, BP20592, 60205 Compiegne (France); Hariri, S. [Ecole des Mines de Douai, Departement Technologies des Polymeres et Composites and Ingenierie Mecanique, 941 rue Charles Bourseul, BP. 10838, 59508 Douai Cedex (France); Herve, C.; Jaubert, L.; Cherfaoui, M. [Pole EPI, Equipements sous Pression et Ingenierie d' Instrumentation, CETIM, 52, Avenue Felix-Lauat, BP80067, 60304 Senlis (France); Mouftiez, A. [Ecole des Mines de Douai, Departement Technologies des Polymeres et Composites and Ingenierie Mecanique, 941 rue Charles Bourseul, BP. 10838, 59508 Douai Cedex (France)

    2012-04-15

    Prior to the detection and monitoring by acoustic emission of defects in steel, this paper deals with the use of waveguide that avoids direct contact between the sensor and monitoring structure when working at high temperature. The study of the waveguide effect on elastic wave transmission shows that waveguide deforms the waveform but it does not affect its frequency. Waveguide length does not affect signal magnitude. An experimental example of compact tensile specimen monitoring by acoustic emission is given. The monitoring of the damage at low and high temperature '450 Degree-Sign C' by acoustic emission enables us to identify crack propagation stages and their acoustic signature. - Highlights: Black-Right-Pointing-Pointer This paper deals with the use of waveguide that avoids direct contact between the sensor and monitoring structure when working at high temperature. Black-Right-Pointing-Pointer The objective is the development of nondestructive testing by acoustic emission (AE) of pressure equipment (PE) operating at high temperature. Black-Right-Pointing-Pointer The use of AE in this work has underlined high temperature mechanical behavior in terms of damage and crack propagation.

  15. Effect of heat input on the microstructure, residual stresses and corrosion resistance of 304L austenitic stainless steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Unnikrishnan, Rahul, E-mail: rahulunnikrishnannair@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Idury, K.S.N. Satish, E-mail: satishidury@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Ismail, T.P., E-mail: tpisma@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Bhadauria, Alok, E-mail: alokbhadauria1@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Shekhawat, S.K., E-mail: satishshekhawat@gmail.com [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay (IITB), Powai, Mumbai 400076, Maharashtra (India); Khatirkar, Rajesh K., E-mail: rajesh.khatirkar@gmail.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India); Sapate, Sanjay G., E-mail: sgsapate@yahoo.com [Department of Metallurgical and Materials Engineering, Visvesvaraya National Institute of Technology (VNIT), South Ambazari Road, Nagpur 440010, Maharashtra (India)

    2014-07-01

    Austenitic stainless steels are widely used in high performance pressure vessels, nuclear, chemical, process and medical industry due to their very good corrosion resistance and superior mechanical properties. However, austenitic stainless steels are prone to sensitization when subjected to higher temperatures (673 K to 1173 K) during the manufacturing process (e.g. welding) and/or certain applications (e.g. pressure vessels). During sensitization, chromium in the matrix precipitates out as carbides and intermetallic compounds (sigma, chi and Laves phases) decreasing the corrosion resistance and mechanical properties. In the present investigation, 304L austenitic stainless steel was subjected to different heat inputs by shielded metal arc welding process using a standard 308L electrode. The microstructural developments were characterized by using optical microscopy and electron backscattered diffraction, while the residual stresses were measured by X-ray diffraction using the sin{sup 2}ψ method. It was observed that even at the highest heat input, shielded metal arc welding process does not result in significant precipitation of carbides or intermetallic phases. The ferrite content and grain size increased with increase in heat input. The grain size variation in the fusion zone/heat affected zone was not effectively captured by optical microscopy. This study shows that electron backscattered diffraction is necessary to bring out changes in the grain size quantitatively in the fusion zone/heat affected zone as it can consider twin boundaries as a part of grain in the calculation of grain size. The residual stresses were compressive in nature for the lowest heat input, while they were tensile at the highest heat input near the weld bead. The significant feature of the welded region and the base metal was the presence of a very strong texture. The texture in the heat affected zone was almost random. - Highlights: • Effect of heat input on microstructure, residual

  16. Comparative study of high temperature oxidation behaviour in AISI 304 and AISI 439 stainless steels

    Directory of Open Access Journals (Sweden)

    Antônio Claret Soares Sabioni

    2003-06-01

    Full Text Available This work deals with a comparison of high temperature oxidation behaviour in AISI 304 austenitic and AISI 439 ferritic stainless steels. The oxidation experiments were performed between 850 and 950 °C, in oxygen and Ar (100 vpm H2. In most cases, it was formed a Cr2O3 protective scale, whose growth kinetics follows a parabolic law. The exception was for the the AISI 304 steel, at 950 °C, in oxygen atmosphere, which forms an iron oxide external layer. The oxidation resistance of the AISI 439 does not depend on the atmosphere. The AISI 304 has the same oxidation resistance in both atmospheres, at 850 °C, but at higher temperatures, its oxidation rate strongly increases in oxygen atmosphere. Concerning the performance of these steels under oxidation, our results show that the AISI 439 steel has higher oxidation resistance in oxidizing atmosphere, above 850 °C, while, in low pO2 atmosphere, the AISI 304 steel has higher oxidation resistance than the AISI 439, in all the temperature range investigated.

  17. Formation of abrasion-resistant coatings of the AlSiFexMny intermetallic compound type on the AISI 304L alloy

    Directory of Open Access Journals (Sweden)

    Martínez-Perales, Laura G.

    2016-03-01

    Full Text Available The α-Al9FeMnSi and β-Al9FeMn2Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 °C, pressure (5, 10 y 20 MPa and holding time (3600, 5400 y 7200 seconds. Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 °C, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of α-Al9FeMnSi and β-Al9FeMn2Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface.Los intermetálicos α-Al9FeMnSi y β-Al9FeMn2Si formados por sinterización reactiva de polvos Al, Si, Mn, Fe, Cr, Ni se han utilizado en aceros AISI 304L para mejorar la microdureza. Las variables de procesamiento de sinterización reactiva fueron temperatura (600, 650, 700, 750, y 800 °C, presión (5, 10 y 20 MPa y el tiempo de retención (3600, 5400 7200 segundos. Los resultados experimentales muestran que la temperatura es la variable más importante que afecta a la formación del sustrato/recubrimiento, mientras que la presión no parece tener un efecto significativo una influencia significativa. Los resultados muestran las condiciones óptimas de la sinterización reactiva que favorecen la formación del sustrato/recubrimiento a 800 °C, 20 MPa y 7200 segundos. En estas condiciones, la zona de reacción entre el sustrato y el recubrimiento es más compacta y bien

  18. Low cycle fatigue: high cycle fatigue damage accumulation in a 304L austenitic stainless steel; Endommagement et cumul de dommage en fatigue dans le domaine de l'endurance limitee d'un acier inoxydable austenitique 304L

    Energy Technology Data Exchange (ETDEWEB)

    Lehericy, Y

    2007-05-15

    The aim of this study was to evaluate the consequences of a Low Cycle Fatigue pre-damage on the subsequent fatigue limit of a 304L stainless steel. The effects of hardening and severe roughness (grinding) have also been investigated. In a first set of tests, the evolution of the surface damage induced by the different LCF pre-cycling was characterized. This has permitted to identify mechanisms and kinetics of damage in the plastic domain for different surface conditions. Then, pre-damaged samples were tested in the High Cycle Fatigue domain in order to establish the fatigue limits associated with each level of pre-damage. Results evidence that, in the case of polished samples, an important number of cycles is required to initiate surface cracks ant then to affect the fatigue limit of the material but, in the case of ground samples, a few number of cycles is sufficient to initiate cracks and to critically decrease the fatigue limit. The fatigue limit of pre-damaged samples can be estimated using the stress intensity factor threshold. Moreover, this detrimental effect of severe surface conditions is enhanced when fatigue tests are performed under a positive mean stress (author)

  19. L2 Milestone 5433: Characterization of Dynamic Behavior of AM and Conventionally Processed Stainless Steel (316L and 304L)

    Energy Technology Data Exchange (ETDEWEB)

    Gray, George Thompson [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Livescu, Veronica [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rigg, P. A. [Washington State Univ., Pullman, WA (United States). Inst. for Shock Physics; Trujillo, Carl Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cady, Carl McElhinney [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chen, Shuh-Rong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carpenter, John S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lienert, Thomas J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fensin, Saryu Jindal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Knapp, Cameron M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Beal, Roberta Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Morrow, Benjamin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dippo, Olivia F. [Univ. of California, San Diego, CA (United States); Jones, David Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Daniel Tito [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Valdez, James Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-26

    For additive manufacturing (AM) of metallic materials, the certification and qualification paradigm needs to evolve as there currently exists no broadly accepted “ASTM- or DIN-type” additive manufacturing certified process or AM-material produced specifications. Accordingly, design, manufacture, and thereafter implementation and insertion of AM materials to meet engineering applications requires detailed quantification of the constitutive (strength and damage) properties of these evolving materials, across the spectrum of metallic AM methods, in comparison/contrast to conventionally-manufactured metals and alloys. This report summarizes the 316L SS research results and presents initial results of the follow-on study of 304L SS. For the AM-316L SS investigation, cylindrical samples of 316L SS were produced using a LENS MR-7 laser additive manufacturing system from Optomec (Albuquerque, NM) equipped with a 1kW Yb-fiber laser. The microstructure of the AM-316L SS was characterized in both the “as-built” Additively Manufactured state and following a heat-treatment designed to obtain full recrystallization to facilitate comparison with annealed wrought 316L SS. The dynamic shock-loading-induced damage evolution and failure response of all three 316L SS materials was quantified using flyer-plate impact driven spallation experiments at peak stresses of 4.5 and 6.35 GPa. The results of these studies are reported in detail in the first section of the report. Publication of the 316L SS results in an archival journal is planned. Following on from the 316L SS completed work, initial results on a study of AM 304L SS are in progress and presented herein. Preliminary results on the structure/dynamic spallation property behavior of AM-304L SS fabricated using both the directed-energy LENS and an EOS powder-bed AM techniques in comparison to wrought 304L SS is detailed in this Level 2 Milestone report.

  20. Dependence of the cyclic stress-strain curve on loading history and its interaction with fatigue of 304L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Belattar, Adel, E-mail: adel.belattar@insa-rouen.fr [INSA Rouen/GPM, UMR CNRS 6634, BP 08, Avenue de l' Universite, 76800 St. Etienne du Rouvray (France); Taleb, Lakhdar; Hauet, Annie [INSA Rouen/GPM, UMR CNRS 6634, BP 08, Avenue de l' Universite, 76800 St. Etienne du Rouvray (France); Taheri, Said [LaMSID UMR EDF-CNRS 2832, Department AMA, 1 Avenue du General de Gaulle, 92141 Clamart Cedex (France)

    2012-02-28

    Highlights: Black-Right-Pointing-Pointer Contrary to low deformation, cyclic curve is not unique at high strain amplitude. Black-Right-Pointing-Pointer However, as the loading was continued cyclic hardening tends to stabilize. Black-Right-Pointing-Pointer Cyclic hardening is mainly kinematic type, isotropic component remains quasi-linear. Black-Right-Pointing-Pointer Increasing in pre-hardening strain amplitude has almost no effect on fatigue damage. Black-Right-Pointing-Pointer Fatigue life decreasing is associated with formation of walls, cells and defect bands. - Abstract: This study investigates the effects of loading history on the cyclic stress-strain curve and fatigue behavior of 304L stainless steel at room temperature. Tension-compression tests were performed on the same specimen under controlled strain, using several loading sequences of increasing or decreasing amplitude. The results show that the cyclic curve is not unique, as it depends on the loading sequence. The same predeformed specimens were subjected to fatigue tests. The results showed that fatigue life is significantly reduced by the previous loading history. A previously developed method for determining the effect of prehardening was evaluated. Microstructural analyses were also performed; the microstructures after preloading and their evolution during the fatigue cycles were characterized by transmission electron microscopy (TEM). The results of these analyses improve our understanding of the macroscopic properties of 304L stainless steel and can help us identify the causes of failure and lifetime reduction.

  1. Experimental investigation of Tie6Ale4V titanium alloy and 304L stainless steel friction welded with copper interlayer

    Institute of Scientific and Technical Information of China (English)

    R. KUMAR; M. BALASUBRAMANIAN

    2015-01-01

    The basic principle of friction welding is intermetallic bonding at the stage of super plasticity attained with self-generating heat due to friction and finishing at upset pressure. Now the dissimilar metal joints are especially popular in defense, aerospace, automobile, bio-medical, refinery and nuclear engineerings. In friction welding, some special alloys with dual phase are not joined successfully due to poor bonding strength. The alloy surfaces after bonding also have metallurgical changes in the line of interfacing. The reported research work in this area is scanty. Although the sound weld zone of direct bonding between Tie6Ale4V and SS304L was obtained though many trials, the joint was not successful. In this paper, the friction welding characteristics between Tie6Ale4V and SS304L into which pure oxygen free copper (OFC) was introduced as interlayer were investigated. BoxeBehnken design was used to minimize the number of experiments to be performed. The weld joint was analyzed for its mechanical strength. The highest tensile strength between Tie6Ale4V and SS304L between which pure copper was used as insert metal was acquired. Micro-structural analysis and elemental analysis were carried out by EDS, and the formation of intermetallic compound at the interface was identified by XRD analysis.

  2. Experimental investigation of Ti–6Al–4V titanium alloy and 304L stainless steel friction welded with copper interlayer

    Directory of Open Access Journals (Sweden)

    R. Kumar

    2015-03-01

    Full Text Available The basic principle of friction welding is intermetallic bonding at the stage of super plasticity attained with self-generating heat due to friction and finishing at upset pressure. Now the dissimilar metal joints are especially popular in defense, aerospace, automobile, bio-medical, refinery and nuclear engineerings. In friction welding, some special alloys with dual phase are not joined successfully due to poor bonding strength. The alloy surfaces after bonding also have metallurgical changes in the line of interfacing. The reported research work in this area is scanty. Although the sound weld zone of direct bonding between Ti–6Al–4V and SS304L was obtained though many trials, the joint was not successful. In this paper, the friction welding characteristics between Ti–6Al–4V and SS304L into which pure oxygen free copper (OFC was introduced as interlayer were investigated. Box–Behnken design was used to minimize the number of experiments to be performed. The weld joint was analyzed for its mechanical strength. The highest tensile strength between Ti–6Al–4V and SS304L between which pure copper was used as insert metal was acquired. Micro-structural analysis and elemental analysis were carried out by EDS, and the formation of intermetallic compound at the interface was identified by XRD analysis.

  3. Laser Welding Of Thin Sheet Of AISI 301 Stainless Steel

    Science.gov (United States)

    Vilar, R.; Miranda, R. M.

    1989-01-01

    Preliminary results of an investigation on laser welding of AISI 301 stainless steel thin sheet are presented. Welds were made with a CO2 continuous wave laser, varying power density and welding speed. The welds were studied by optical and electron scanning microscopy, X-ray diffraction and hardness tests. Experimental results show that under appropriate conditions, sound welds are obtained, with a negligeable heat affected zoneanda fine microstructure in the fusion zone. The fusion zone shows a cellular - dendritic microstructure, with austenite and ferrite as the major constituents. Ferrite, whose content is 5 to 7%, is predominantly intradendritic with both vermicular and acicular morphologies. However some interdendritic ferrite may also be present. The characteristics of the structure suggest that the solidification mode of AISI 301 stainless steel is essentially ferritic.

  4. Materials Reliability Program: Environmental Fatigue Testing of Type 304L Stainless Steel U-Bends in Simulated PWR Primary Water (MRP-137)

    Energy Technology Data Exchange (ETDEWEB)

    R.Kilian

    2004-12-01

    Laboratory data generated in the past decade indicate a significant reduction in component fatigue life when reactor water environmental effects are experimentally simulated. However, these laboratory data have not been supported by nuclear power plant component operating experience. In recent comprehensive review of laboratory, component and structural test data performed through the EPRI Materials Reliability Program, flow rate was identified as a critical variable that was generally not considered in laboratory studies but applicable in plant operating environments. Available data for carbon/low-alloy steel piping components suggest that high flow is beneficial regarding the effects of a reactor water environment. Similar information is lacking for stainless steel piping materials. This report documents progress made to date in an extensive testing program underway to evaluate the effects of flow rate on the corrosion fatigue of 304L stainless steel under simulated PWR primary water environmental conditions.

  5. Influence of low-temperature nitriding on the strain-induced martensite and laser-quenched austenite in a magnetic encoder made from 304L stainless steel.

    Science.gov (United States)

    Leskovšek, Vojteh; Godec, Matjaž; Kogej, Peter

    2016-08-05

    We have investigated the possibility of producing a magnetic encoder by an innovative process. Instead of turning grooves in the encoder bar for precise positioning, we incorporated the information in 304L stainless steel by transforming the austenite to martensite after bar extrusion in liquid nitrogen and marking it with a laser, which caused a local transformation of martensite back into austenite. 304L has an excellent corrosion resistance, but a low hardness and poor wear resistance, which limits its range of applications. However, nitriding is a very promising way to enhance the mechanical and magnetic properties. After low-temperature nitriding at 400 °C it is clear that both ε- and α'-martensite are present in the deformed microstructure, indicating the simultaneous stress-induced and strain-induced transformations of the austenite. The effects of a laser surface treatment and the consequent appearance of a non-magnetic phase due to the α' → γ transformation were investigated. The EDS maps show a high concentration of nitrogen in the alternating hard surface layers of γN and α'N (expanded austenite and martensite), but no significantly higher concentration of chromium or iron was detected. The high surface hardness of this nitride layer will lead to steels and encoders with better wear and corrosion resistance.

  6. Influence of low-temperature nitriding on the strain-induced martensite and laser-quenched austenite in a magnetic encoder made from 304L stainless steel

    Science.gov (United States)

    Leskovšek, Vojteh; Godec, Matjaž; Kogej, Peter

    2016-08-01

    We have investigated the possibility of producing a magnetic encoder by an innovative process. Instead of turning grooves in the encoder bar for precise positioning, we incorporated the information in 304L stainless steel by transforming the austenite to martensite after bar extrusion in liquid nitrogen and marking it with a laser, which caused a local transformation of martensite back into austenite. 304L has an excellent corrosion resistance, but a low hardness and poor wear resistance, which limits its range of applications. However, nitriding is a very promising way to enhance the mechanical and magnetic properties. After low-temperature nitriding at 400 °C it is clear that both ε- and α‧-martensite are present in the deformed microstructure, indicating the simultaneous stress-induced and strain-induced transformations of the austenite. The effects of a laser surface treatment and the consequent appearance of a non-magnetic phase due to the α‧ → γ transformation were investigated. The EDS maps show a high concentration of nitrogen in the alternating hard surface layers of γN and α‧N (expanded austenite and martensite), but no significantly higher concentration of chromium or iron was detected. The high surface hardness of this nitride layer will lead to steels and encoders with better wear and corrosion resistance.

  7. Glow Discharge Plasma Nitriding of AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    A.QAYYUM; M.A.NAVEED; S.ZEB; G.MURTAZA; M.ZAKAULLAH

    2007-01-01

    Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis.The treated samples were analysed by X-ray diffraction(XRD)to explore the changes induced in the crystallographic structure.The XRD pattern confirmed the formation of an expanded austenite phase(γN)owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice.A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth(μm).The results showed clear evidence of surface changes with substantial increase in surface hardness.

  8. COLD ROLLING ORTHODONTIC WIRES OF AUSTENITIC STAINLESS STEEL AISI 304

    Directory of Open Access Journals (Sweden)

    Rodrigo Santos Messner

    2013-03-01

    Full Text Available Austenitic stainless steels wires are widely used in the final stages of orthodontic treatment. The objective of this paper is to study the process of conformation of rectangular wires from round wires commercial austenitic stainless steel AISI 304 by the process of cold rolling. The wire quality is evaluated by means of dimensional analysis, microhardness measurements, tensile strength and fractographic analysis of the wires subjected to tensile tests. Also a study on the application of finite element method to simulate the process, comparing the force and rolling stress obtained in the rolling is done. The simulation results are consistent with those obtained in the actual process and the rolled wires show ductile fracture, tensile strength and dimensional variations appropriate to orthodontic standards. The fracture morphology shows the model cup-cone type besides the high deformation and hardness inherent in the cold rolling process.

  9. Microestrutura de uma Solda Dissimilar entre o Aço Inoxidável Ferrítico AISI 410S e o Aço Inoxidável Austenítico AISI 304L Soldado pelo Processo FSW

    Directory of Open Access Journals (Sweden)

    Tathiane Caminha Andrade

    2015-12-01

    Full Text Available Resumo O presente trabalho visa investigar a microestrutura formada na soldagem dissimilar entre chapas de aços inoxidáveis ferríticos AISI 410S e aços inoxidáveis austeníticos AISI 304L pelo processo friction stir welding. A soldagem foi realizada com o ajuste dos seguintes parâmetros: rotação 450 rpm; velocidade de soldagem de 1,0 mm/s; e força axial 40 kN. O aço AISI 410S foi posicionado no lado de avanço enquanto que o aço AISI 304L foi posicionado no lado de retrocesso. A análise consistiu de preparação metalográfica e caracterização microestrutural por microscopia ótica e microscopia eletrônica de varredura. Para o aço AISI 410S foi observada a formação de martensita associada com ferrita na zona de mistura (ZM, zona termomecanicamente afetada (ZTMA e na zona afetada pelo calor (ZAC. As características do processo de soldagem FSW resultaram num refino de grão para o aço inoxidável ferrítico, posicionado no lado de avanço, tanto na ZM quanto nas ZTMA e ZAC. O mesmo comportamento não foi observado para o lado austenítico.

  10. Biomaterial Studies on AISI 316L Stainless Steel after Magnetoelectropolishing

    Directory of Open Access Journals (Sweden)

    Massimiliano Filippi

    2009-03-01

    Full Text Available The polarisation characteristics of the electropolishing process in a magnetic field (MEP – magnetoelectropolishing, in comparison with those obtained under standard/conventional process (EP conditions, have been obtained. The occurrence of an EP plateau has been observed in view of the optimization of MEP process. Up-to-date stainless steel surface studies always indicated some amount of free-metal atoms apart from the detected oxides and hydroxides. Such a morphology of the surface film usually affects the thermodynamic stability and corrosion resistance of surface oxide layer and is one of the most important features of stainless steels. With this new MEP process we can improve metal surface properties by making the stainless steel more resistant to halides encountered in a variety of environments. Furthermore, in this paper the stainless steel surface film study results have been presented. The results of the corrosion research carried out by the authors on the behaviour of the most commonly used material - medical grade AISI 316L stainless steel both in Ringer’s body fluid and in aqueous 3% NaCl solution have been investigated and presented earlier elsewhere, though some of these results, concerning the EIS Nyquist plots and polarization curves are also revealed herein. In this paper an attempt to explain this peculiar performance of 316L stainless steel has been undertaken. The SEM studies, Auger electron spectroscopy (AES and X-ray photoelectron spectroscopy (XPS were performed on 316L samples after three treatments: MP – abrasive polishing (800 grit size, EP – conventional electrolytic polishing, and MEP – magnetoelectropolishing. It has been found that the proposed magnetoelectropolishing (MEP process considerably modifies the morphology and the composition of the surface film, thus leading to improved corrosion resistance of the studied 316L SS.

  11. Investigation of Machinability Characteristics of AISI 316Ti Stainless Steel

    Directory of Open Access Journals (Sweden)

    Yunus Kayır

    2012-01-01

    Full Text Available In this study, many experiments of machinability were carried out on universal turning lathe. The cutting forces that occur during machining of workpieces were measured. A standard dynamometer was used to measure cutting forces. The Dynamometer were assembled on the lathe efficiently. An apart were designed and machined to assembly the dynamometer. Moreover, AISI 316Ti stainless steel parts were turned by carbide cutting tools coated with TiAlN components. Effects of cutting tools with different radius on cutting forces and surface roughness were investigated by using different cutting parameters. Moreover, machined parts' surface roughness was controlled. The experimental results showed that cutting forces increased with the increasing federate, but the surface roughness decreased with increasing the radius of cutting edge.

  12. The Study of Plasma Nitriding of AISI304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; JI Shi-jun; GAO Yu-zhou; SUN Jun-cai

    2004-01-01

    This paper presents results on the plasma nitriding of AISI 304 stainless steel at different temperatures in NH 3 gas. The working pressure was 100~200 Pa and the discharge voltage was 700~800V. The phase of nitrided layer formed on the surface was confirmed by X-ray diffraction. The hardness of the samples was measured by using a Vickers microhardness tester with the load of 50g. After nitriding at about 400 ℃ for two hours a nitrided layer consisting of single γN phase with thickness of 5μm was obtained. Microhardness measurements showed significant increase in the hardness from 240 HV (for untreated samples) up to 950 HV (for nitrided samples at temperature of 420℃). The phase composition, the thickness, the microstructure and the surface topography of the nitrided layer as well as its properties depend essentially on the process parameters.

  13. Tensile and Impact Properties of Shielded Metal Arc Welded AISI 409M Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    K.Shanmugam; A.K.Lakshminarayanan; V.Balasubramanian

    2009-01-01

    The present study is concerned with the effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the joints fabricated by austenitic stainless steel, ferritic stainless steel and duplex stainless steel filler metals were evaluated and the results were reported. From this investigation, it is found that the joints fabricated by duplex stainless steel filler metal showed higher tensile strength and hardness compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Joints fabricated by austenitic stainless steel filler metal exhibited higher ductility and impact toughness compared with the joints fabricated by ferritic stainless steel and duplex stainless steel filler metals.

  14. Heat transfer and fluid flow during keyhole mode laser welding of tantalum, Ti 6Al 4V, 304L stainless steel and vanadium

    Science.gov (United States)

    Rai, R.; Elmer, J. W.; Palmer, T. A.; Roy, T. Deb

    2007-09-01

    Because of the complexity of several simultaneous physical processes, most heat transfer models of keyhole mode laser welding require some simplifications to make the calculations tractable. The simplifications often limit the applicability of each model to the specific materials systems for which the model is developed. In this work, a rigorous, yet computationally efficient, keyhole model is developed and tested on tantalum, Ti-6Al-4V, 304L stainless steel and vanadium. Unlike previous models, this one combines an existing model to calculate keyhole shape and size with numerical fluid flow and heat transfer calculations in the weld pool. The calculations of the keyhole profile involved a point-by-point heat balance at the keyhole walls considering multiple reflections of the laser beam in the vapour cavity. The equations of conservation of mass, momentum and energy are then solved in three dimensions assuming that the temperatures at the keyhole wall reach the boiling point of the different metals or alloys. A turbulence model based on Prandtl's mixing length hypothesis was used to estimate the effective viscosity and thermal conductivity in the liquid region. The calculated weld cross-sections agreed well with the experimental results for each metal and alloy system examined here. In each case, the weld pool geometry was affected by the thermal diffusivity, absorption coefficient, and the melting and boiling points, among the various physical properties of the alloy. The model was also used to better understand solidification phenomena and calculate the solidification parameters at the trailing edge of the weld pool. These calculations indicate that the solidification structure became less dendritic and coarser with decreasing weld velocities over the range of speeds investigated in this study. Overall, the keyhole weld model provides satisfactory simulations of the weld geometries and solidification sub-structures for diverse engineering metals and alloys.

  15. Study on the Effect of Laser Welding Parameters on the Microstructure and Mechanical Properties of Ultrafine Grained 304L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Reihane Nafar Dehsorkhi

    2016-12-01

    Full Text Available In the present study, an ultrafine grained (UFG 304L stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. Weldability of the UFG sample was studied by Nd: YAG laser welding under different welding conditions. Taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duration on the resultant microstructure and mechanical properties. X-ray Diffraction (XRD, Optical Microscope (OM, Scanning Electron Microscope (SEM, Transmission Electron Microscope (TEM, microhardness measurements and tension tests were conducted to characterize the sample after thermomechanical processing and laser welding. The results showed that the ultrafine grained steel had the yield strength of 1000 Mpa and the total elongation of 48%, which were almost three times higher than those of the as-received sample. The microstructure of the weld zone was shown to be a mixture of austenite and delta ferrite. The microhardness of the optimized welded sample (315 HV0.5 was found to be close to the UFG base metal (350 HV. It was also observed that the hardness of the heat affected zone (HAZ was  lower than that of the weld zone, which was related to the HAZ grain growth during laser welding. The results of optimization also showed that the welding time was the most important parameter affecting the weld strength. Overall, the study showed that laser welding could be an appropriate and alternative welding technique for the joining of UFG steels.

  16. Study on tempering behaviour of AISI 410 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Gopa, E-mail: gopa_mjs@igcar.gov.in [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Das, C.R.; Albert, S.K.; Bhaduri, A.K.; Thomas Paul, V. [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Panneerselvam, G. [Chemistry Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Dasgupta, Arup [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India)

    2015-02-15

    Martensitic stainless steels find extensive applications due to their optimum combination of strength, hardness and wear-resistance in tempered condition. However, this class of steels is susceptible to embrittlement during tempering if it is carried out in a specific temperature range resulting in significant reduction in toughness. Embrittlement of as-normalised AISI 410 martensitic stainless steel, subjected to tempering treatment in the temperature range of 673–923 K was studied using Charpy impact tests followed by metallurgical investigations using field emission scanning electron and transmission electron microscopes. Carbides precipitated during tempering were extracted by electrochemical dissolution of the matrix and identified by X-ray diffraction. Studies indicated that temper embrittlement is highest when the steel is tempered at 823 K. Mostly iron rich carbides are present in the steel subjected to tempering at low temperatures of around 723 K, whereas chromium rich carbides (M{sub 23}C{sub 6}) dominate precipitation at high temperature tempering. The range 773–823 K is the transition temperature range for the precipitates, with both Fe{sub 2}C and M{sub 23}C{sub 6} types of carbides coexisting in the material. The nucleation of Fe{sub 2}C within the martensite lath, during low temperature tempering, has a definite role in the embrittlement of this steel. Embrittlement is not observed at high temperature tempering because of precipitation of M{sub 23}C{sub 6} carbides, instead of Fe{sub 2}C, preferentially along the lath and prior austenite boundaries. Segregation of S and P, which is widely reported as one of the causes for temper embrittlement, could not be detected in the material even through Auger electron spectroscopy studies. - Highlights: • Tempering behaviour of AISI 410 steel is studied within 673–923 K temperature range. • Temperature regime of maximum embrittlement is identified as 773–848 K. • Results show that type of

  17. Deformation induced martensite in AISI 316 stainless steel

    Directory of Open Access Journals (Sweden)

    Solomon, N.

    2010-04-01

    Full Text Available The forming process leads to a considerable differentiation of the strain field within the billet, and finally causes the non-uniform distribution of the total strain, microstrusture and properties of the material over the product cross-section. This paper focus on the influence of stress states on the deformation-induced a’ martensitic transformation in AISI Type 316 austenitic stainless steel. The formation of deformation-induced martensite is related to the austenite (g instability at temperatures close or below room temperature. The structural transformation susceptibility is correlated to the stacking fault energy (SFE, which is a function not only of the chemical composition, but also of the testing temperature. Austenitic stainless steels possess high plasticity and can be easily cold formed. However, during cold processing the hardening phenomena always occurs. Nevertheless, the deformation-induced martensite transformation may enhance the rate of work-hardening and it may or may not be in favour of further material processing. Due to their high corrosion resistance and versatile mechanical properties the austenitic stainless steels are used in pressing of heat exchanger plates. However, this corrosion resistance is influenced by the amount of martensite formed during processing. In order to establish the links between total plastic strain, and martensitic transformation, the experimental tests were followed by numerical simulation.

    El proceso de conformación da a lugar a una considerable diferenciación del campo de tensiones dentro de una barra de extrusión y, finalmente, causa una distribución no uniforme de la tensión total, la microestructura y propiedades del material sobre el corte transversal. En este trabajo se estudia la influencia de los estados de tensión sobre la transformación martensítica inducida por deformación en un acero inoxidable austenítico tipo AISI 316. La formación de martensita inducida por

  18. Activated flux tungsten inert gas welding of 8 mm-thick AISI 304 austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    刘观辉; 刘美华; 易耀勇; 张宇鹏; 罗子艺; 许磊

    2015-01-01

    AISI 304 stainless steel plates were welded with activated flux tungsten inert gas (A-TIG) method by utilizing self-developed activated flux. It is indicated from the experimental results that for 8 mm-thick AISI 304 stainless steel plate, weld joint of full penetration and one-side welding with good weld appearance can be obtained in a single pass without groove preparation by utilizing A-TIG welding. Moreover, activated flux powders do not cause significant effect on the microstructure of TIG weld and the mechanical properties of A-TIG weld joints are also superior to those of C-TIG (conventional TIG) welding.

  19. Correlation of radiation-induced changes in microstructure/microchemistry, density and thermo-electric power of type 304L and 316 stainless steels irradiated in the Phénix reactor

    Energy Technology Data Exchange (ETDEWEB)

    Renault Laborne, Alexandra, E-mail: alexandra.renault@cea.fr [CEA, DEN, SRMA, F-91191 Gif-sur-Yvette (France); Gavoille, Pierre [CEA, DEN, SEMI, F-91191 Gif-sur-Yvette (France); Malaplate, Joël [CEA, DEN, SRMA, F-91191 Gif-sur-Yvette (France); Pokor, Cédric [EDF R& D, MMC, Site des Renardières, F-77818 Morêt-sur-Loing cedex (France); Tanguy, Benoît [CEA, DEN, SEMI, F-91191 Gif-sur-Yvette (France)

    2015-05-15

    Annealed specimens of type 304L and 316 stainless steel and cold-worked 316 specimens were irradiated in the Phénix reactor in the temperature range 381–394 °C and to different damage doses up to 39 dpa. The microstructure and microchemistry of both 304L and 316 have been examined using the combination of the different techniques of TEM to establish the void swelling and precipitation behavior under neutron irradiation. TEM observations are compared with results of measurements of immersion density and thermo-electric power obtained on the same irradiated stainless steels. The similarities and differences in their behavior on different scales are used to understand the factors in terms of the chemical composition and metallurgical state of steels, affecting the precipitation under irradiation and the swelling behavior. Irradiation induces the formation of some precipitate phases (e.g., M{sub 6}C and M{sub 23}C{sub 6}-type carbides, and γ’- and G-phases), Frank loops and cavities. According to the metallurgical state and chemical composition of the steel, the amount of each type of radiation-induced defects is not the same, affecting their density and thermo-electric power.

  20. AES depth profiles in Mo-coated 304L stainless steel achieved by RF-magnetron sputtering and influence of Mo on the corrosion in 3.5% NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Saidi, D. [Département de métallurgie, Division de Technologie du Combustible, Centre de Recherche Nucléaire de Draria CRND, BP. 43 Draria, Alger (Algeria); Zaid, B., E-mail: zaidbachir@yahoo.com [Département de métallurgie, Division de Technologie du Combustible, Centre de Recherche Nucléaire de Draria CRND, BP. 43 Draria, Alger (Algeria); Souami, N. [Centre de Recherche Nucléaire d’Alger CRNA, 2 Bd. Frantz Fanon, Alger (Algeria); Saoula, N. [Division des Milieux Ionisés et Lasers, Centre de Développement des Technologies Avancées CDTA, Cité du 20 août 1956, Baba Hassan, BP n 17, Alger (Algeria); Siad, M. [Centre de Recherche Nucléaire d’Alger CRNA, 2 Bd. Frantz Fanon, Alger (Algeria); Si Ahmed, A. [Im2np, UMR 7334 CNRS, Aix-Marseille Université, 13397 Marseille Cedex 20 (France); Biberian, J.P. [CINaM, UMR 7525 CNRS, Aix Marseille Université, 13288 Marseille Cedex 9 (France)

    2015-10-05

    Highlights: • Mo coating of 304L stainless steel is achieved via RF-magnetron sputtering. • The AES depth profiles before and after annealing in air (at 973 K) are analyzed. • The corrosions in NaCl solution of bare and Mo-coated samples are compared. • Mo-coated steels exhibit better corrosion behaviors. • The positive action of Mo oxide via its semi-conducting properties is deduced. - Abstract: Molybdenum-coated 304L stainless steel samples, fabricated by RF-magnetron sputtering, are characterized by Auger Electron Spectroscopy (AES) before and after annealing in air at 973 K. The electrochemical parameters of bare and coated materials, in NaCl 3.5% water solution at 298 K, are derived from the potentiodynamic polarization curves. The corrosion current of Mo-coated samples (before and after annealing) is significantly lower than that of its bare counterpart. The information gained from the AES depth profiles leads us to infer that the positive action of molybdenum on the corrosion behavior may be attributed to the changes induced by the semi-conducting properties of Mo oxide in the passive film.

  1. The adhesion of hot-filament CVD diamond films on AISI type 316 austenitic stainless steel

    NARCIS (Netherlands)

    Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

    2004-01-01

    Steel ball indentation and scratch adhesion testing of hot filament chemical vapour deposited diamond films onto AISI type 316 austenitic stainless steel substrates using two different interlayer systems, namely chromium nitride and borided steel, have been investigated. In order to compare the adhe

  2. Nitriding Process Characterization of Cold Worked AISI 304 and 316 Austenitic Stainless Steels

    Directory of Open Access Journals (Sweden)

    Waldemar Alfredo Monteiro

    2017-01-01

    Full Text Available The nitriding behavior of austenitic stainless steels (AISI 304 and 316 was studied by different cold work degree (0% (after heat treated, 10%, 20%, 30%, and 40% before nitride processing. The microstructure, layer thickness, hardness, and chemical microcomposition were evaluated employing optical microscopy, Vickers hardness, and scanning electron microscopy techniques (WDS microanalysis. The initial cold work (previous plastic deformations in both AISI 304 and 306 austenitic stainless steels does not show special influence in all applied nitriding kinetics (in layer thicknesses. The nitriding processes have formed two layers, one external layer formed by expanded austenite with high nitrogen content, followed by another thinner layer just below formed by expanded austenite with a high presence of carbon (back diffusion. An enhanced diffusion can be observed on AISI 304 steel comparing with AISI 316 steel (a nitrided layer thicker can be noticed in the AISI 304 steel. The mechanical strength of both steels after nitriding processes reveals significant hardness values, almost 1100 HV, on the nitrided layers.

  3. Zirconium oxide deposits (ZrO{sub 2}) and titanium oxide (TiO{sub 2}) on 304l stainless steel; Depositos de oxido de circonio (ZrO{sub 2}) y oxido de titanio (TiO{sub 2}) sobre acero inoxidable 304L

    Energy Technology Data Exchange (ETDEWEB)

    Davila N, M. L.

    2015-07-01

    This research project aims to carry out the surface and electrochemical characterization to obtain the optimum conditions of the hydrothermal deposits of zirconium oxide ZrO{sub 2} (baddeleyite) and titanium oxide TiO{sub 2} (anatase and rutile phases) on 304l stainless steel, simulating an inhibiting protective layer. 304l steel specimens were cut, pre-oxidized in water at a temperature of 288 degrees Celsius and 8 MPa, similar to those of a typical BWR conditions. From the titanium oxide anatase crystalline phase, the rutile phase was obtained by a heat treatment at 1000 degrees Celsius. The Sigma-Aldrich pre-oxidized powders and steel 304l were characterized using techniques of X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, chemical mapping and Raman spectrometry. The pre-oxidized steel has two oxide layers, an inner layer with nano metric crystals and another outer of larger crystals to 1μm, with the formation of hematite and magnetite, this predominating. The surface that contacted the sample holder has larger crystals. Hydrothermal deposits were carry out from suspensions of 10, 100 and 1000 ppm, of the crystal phases of anatase, rutile and baddeleyite, on the pre-oxidized steel at a temperature of 150 degrees Celsius for 2 and 7 days, samples were analyzed by X-ray diffraction, scanning electron microscopy, X-ray dispersive energy, Raman spectrometry and Tafel polarization. The suspension to 1000 ppm for 7 days coated surface most; the baddeleyite deposit is noticed more homogeneous than anatase and rutile. The deposit is favored when hematite and magnetite crystals are larger. The chemical mapping on deposits show that even after being immersed in water to 288 degrees Celsius during 30 days, the deposits are still present although a loss is observed. A reference electrode was assembled to conduct electrochemical tests of Tafel able to withstand a temperature of 288 degrees Celsius and pressure of 8 MPa. The baddeleyite deposit

  4. Thermal fatigue of a 304L austenitic stainless steel: simulation of the initiation and of the propagation of the short cracks in isothermal and aniso-thermal fatigue; Fatigue thermique d'un acier inoxydable austenitique 304L: simulation de l'amorcage et de la croissance des fissures courtes en fatigue isotherme et anisotherme

    Energy Technology Data Exchange (ETDEWEB)

    Haddar, N

    2003-04-01

    The elbow pipes of thermal plants cooling systems are submitted to thermal variations of short range and of variable frequency. These variations bound to temperature changes of the fluids present a risk of cracks and leakages. In order to solve this problem, EDF has started the 'CRECO RNE 808' plan: 'thermal fatigue of 304L austenitic stainless steels' to study experimentally on a volume part, the initiation and the beginning of the propagation of cracks in thermal fatigue on austenitic stainless steels. The aim of this study is more particularly to compare the behaviour and the damage of the material in mechanic-thermal fatigue (cycling in temperature and cycling in deformation) and in isothermal fatigue (the utmost conditions have been determined by EDF for the metal: Tmax = 165 degrees C and Tmin = 90 degrees C; the frequency of the thermal variations can reach a Hertz). A lot of experimental results are given. A model of lifetime is introduced and validated. (O.M.)

  5. Effect of heat treatment on an AISI 304 austenitic stainless steel evaluated by the ultrasonic attenuation coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Moghanizadeh, Abbas; Farzi, Abolfazl [Islamic Azad Univ., Esfarayen (Iran, Islamic Republic of). Dept. of Civil Engineering

    2016-07-01

    The properties of metals can be substantially changed by various methods, one of them is using heat treatment processes. Moreover, ultrasonic testing is the most preferred and effective, nondestructive testing technique for characterization of mechanical material properties. Austenitic stainless steel AISI 304 serves in many applications due to high strength and corrosion resistance. In certain applications, it is important to evaluate the mechanical properties of AISI 304 stainless steel. In this study, the ultrasonic method (attenuation measurement technique) is used to evaluate the hardness of AISI 304 stainless steel samples which were heat treated at different levels. Due to the heat treatment process, each sample has its specific microstructure and hardness which attenuate ultrasonic waves appropriately. The ultrasonic and hardness test show that it is possible to evaluate the hardness of AISI 304 stainless steel by ultrasonic attenuation coefficient. In addition, the relationship between ultrasonic attenuation coefficients and time of heat treatment is investigated.

  6. Influence of the surface finishing on electrochemical corrosion characteristics of AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Sylvia Dundeková

    2015-05-01

    Full Text Available Stainless steels from 316 group are very often and successfully uses for medical applications where the good mechanical and chemical properties in combination with non-toxicity of the material assure its safe and long term usage. Corrosion properties of AISI 361L stainless steel are strongly influenced by surface roughness and treatment of the engineering parts (specimens and testing temperature. Electrochemical characteristics of ground, mechanically polished and passivated AISI 316L stainless steel specimens were examined with the aim to identify the polarization resistance evolution due to the surface roughness decrease. Results obtained on mechanically prepared specimens where only natural oxide layer created due to the exposure of the material to the corrosion environment was protecting the materials were compared to the passivated specimens with artificial oxide layer. Also the influence of temperature and stabilization time before measurement were taken into account when discussing the obtained results. Positive influence of decreasing surface roughness was obtained as well as increase of polarization resistance due to the chemical passivation of the surface. Increase of the testing temperature and short stabilization time of the specimen in the corrosion environment were observed negatively influencing corrosion resistance of AISI 316L stainless steel.

  7. EFFECTS OF COPPER ION IMPLANTATION ON ANTIBACTERIAL ACTIVITY OF AISI420 STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    Z.G. Dan; H.W. Ni; B.F. Xu; J. Xiong; P. Y. Xiong

    2005-01-01

    Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2.0×1017ions .cm-2. The saturation dose of Cu implantation in AISI420 SS and Cu surface concentration were calculated at the energy of 100keV. The effect of dose on the antibacterial activity was analyzed. Results of antibacterial test show that the saturation dose is the optimum implantation dose for best antibacterial activity, which is above 99% against both Escherichia coli and Staphylococcus aureus. Novel phases such as Fe4Cu3 and Cu9.9Fe0.1 were found in the implanted layer by glancing angle X-ray diffraction (GXRD). The antibacterial activity of AISI420 SS attributes to Cu-contained phase.

  8. In Situ Observation of Solidification Process of AISI 304 Austenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    HUANG Fu-xiang; WANG Xin-hua; ZHANG Jiong-ming; JI Chen-xi; FANG Yuan; YU Yan

    2008-01-01

    The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope(CSLM).The results show that the δ phase appeared first in liquid steel,as the temperature decreased,the γ phase precipitated prior at δ-grain boundary at 1452.2℃,the liquid steel disappeared at 1431.3℃,and then theγphase precipitated on the δ ferrite.Based on the Scheil-GulliVer solidification model,the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in Thermo-Calc.and the simulation results agree well with the results observed in the experiment.

  9. Welding of AA1050 aluminum with AISI 304 stainless steel by rotary friction welding process

    OpenAIRE

    Chen Ying An; Francisco Piorino Neto; Eder Paduan Alves

    2010-01-01

    The purpose of this work was to assess the development of solid state joints of dissimilar material AA1050 aluminum and AISI 304 stainless steel, which can be used in pipes of tanks of liquid propellants and other components of the Satellite Launch Vehicle. The joints were obtained by rotary friction welding process (RFW), which combines the heat generated from friction between two surfaces and plastic deformation. Tests were conducted with different welding process parameters. The results we...

  10. Cathodic cage nitriding of AISI 409 ferritic stainless steel with the addition of CH4

    Directory of Open Access Journals (Sweden)

    Rômulo Ribeiro Magalhães de Sousa

    2012-04-01

    Full Text Available AISI 409 ferritic stainless steel samples were nitrided using the cathodic cage plasma nitriding technique (CCPN, with the addition of methane to reduce chromium precipitation, increase hardness and wear resistance and reduce the presence of nitrides when compared to plasma carbonitriding. Microhardness profiles and X-Ray analysis confirm the formation of a very hard layer containing mainly ε-Fe3N and expanded ferrite phases.

  11. Study of diffusion welding between the zirconium alloy Zy{sub 4} and the stainless steel 304L. Morphology of the interface and nature of the phases formed; Etude du soudage diffusion entre l'alliage de zirconium Zy{sub 4} et l'acier inoxydable 304L. Morphologie de l'interface et nature des phases formees

    Energy Technology Data Exchange (ETDEWEB)

    Taouinet, M. [Centre de Recherche Nucleaire de Draria (CRNA), Alger (Algeria); Lebaili, S. [Universite des Sciences et de la Technologie Houari Boumediene, Lab. de Science et Genie des Materiaux, Faculte de Genie Mecanique et Genie des Procedes, Alger (Algeria); Souami, N. [Centre de Recherche Nucleaire d' Alger (CRNA), Alger (Algeria)

    2009-07-01

    We approach a study on the solid state diffusion bonding between zircaloy (Zy{sub 4}) and stainless steel (304L) for an application in the sector of the nuclear power. The diffusion couples prepared underwent treatments at the temperatures ranging between 850 and 1020 C in a controlled atmosphere and under dynamic pressures. We give a particular attention to the morphology of the interface, formed, and to the determination of the nature of the compounds formed. The observations and chemical analysis are realized by ESEM-EDX and XRD. The quantitative distribution as well as the detailed localization of the basic chemical elements are defined by chemical profiles, and series of images X. The junction of diffusion consists of three zones distinct, formed from a solid solution FeCr({alpha}), rich in Cr in the form of a homogeneous edge, localized in steel side. The two other zones of the center of the Zy{sub 4} side are two phase of type Zr{sub {alpha}}, (FeCr){sub {alpha}}-Zr(Fe, Cr){sub 2} and Zr{sub {alpha}}-Zr{sub 2}(Fe{sub 1-x}Ni{sub x}), 0.15{<=}x{<=}0.25. The detailed results obtained, are a regrouping, between those obtained from the observations and chemical analysis and radio crystallographic. The values of the measured micro-hardnesses give very heterogeneous filiations to the level of the interface. (authors)

  12. Superficial and electrochemical study of stainless steel 304l with an inhibitory protective coating (TiO{sub 2} and ZrO{sub 2}); Estudio superficial y electroquimico de acero inoxidable 304L con una capa protectora inhibidora (TiO{sub 2} y ZrO{sub 2})

    Energy Technology Data Exchange (ETDEWEB)

    Davila N, M. L.; Contreras R, A.; Arganis J, C. R., E-mail: aida.contreras@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    The degradation mechanisms in the boiling water reactors (BWR) have been an alert focus for owners, especially the cracking by stress corrosion cracking (SCC), therefore different techniques have been studied to inhibit this problem inside which is the water injection of hydrogen feeding (HWC, Hydrogen Water Chemistry), together with the noble metals injection (NMCA, Nobel Metal Chemical Addition) and the ceramic materials injection that form an inhibitory protective coating (Ipc). In this work the Ipc was simulated, for which were carried out hydro-thermals deposits starting from suspensions of 1000 ppm of zirconium oxide in its crystalline phase baddeleyite and titanium oxides in its anatase and rutile phases, on test tubes of stainless steel 304l previously rusty under simulated conditions of pressure and temperature of a BWR (288 C and 8 MPa). The superficial characterization was realized by scanning electron microscopy, energy-dispersive of X-ray and X-ray diffraction. The capacity to mitigate the corrosion was studied with the electrochemical technique of Tafel polarization (288 C and 8 MPa). The steel presents the formation of two oxide coatings formed by magnetite and hematite. The baddeleyite presents a deposit more thick and homogeneous it also presents the most negative electrochemical potential of corrosion, what indicates that it has the bigger capacity to mitigate the SCC. (Author)

  13. Mechanical and Microstructural Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel AISI 1060

    Directory of Open Access Journals (Sweden)

    Ates H.

    2014-10-01

    Full Text Available Rotary Friction welding is one of the most popular methods of joining similar and dissimilar materials. It is widely used with metals and thermoplastics in a wide variety of aviation, transport and aerospace industrial component designs. This study investigates the influence of friction and upsetting pressures on the hardness, tensile properties and microstructure of the welds. The experimental results showed that as the friction and upsetting pressures increased, the hardness and tensile strength values increased, as well. The tensile fracture of welded joint occurred in the AISI 1060 side. The friction processed joints were evaluated for their integrity and quality aspects by optical and scanning electron microscopy. For the perfect interfacial bonding, sufficient upsetting and friction pressures are necessary to reach the optimal temperature and severe plastic deformation to bring these materials within the attraction range.

  14. Structure and properties of the Stainless steel AISI 316 nitrided with microwave plasma; Estructura y propiedades del acero inoxidable AISI 316 nitrurado con plasmas de microondas

    Energy Technology Data Exchange (ETDEWEB)

    Becerril R, F

    1999-07-01

    In this work were presented the results obtained by nitridation on stainless steel AISI 316 using a plasma generated through a microwave discharge with an external magnetic field using several moistures hydrogen / nitrogen to form a plasma. The purpose of nitridation was to increase the surface hardness of stainless steel through a phase formation knew as {gamma}N which has been reported that produces such effect without affect the corrosion resistance proper of this material. (Author)

  15. Linear friction welding of AISI 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Bhamji, Imran, E-mail: imran.bhamji@postgrad.manchester.ac.uk [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Preuss, Michael [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Threadgill, Philip L. [Formerly with TWI Ltd., Cambridge, UK (now retired) (United Kingdom); Moat, Richard J. [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Addison, Adrian C. [TWI Ltd., Cambridge (United Kingdom); Peel, Matthew J. [University of Bristol, Queens Building, University Walk, Bristol BS8 1TR (United Kingdom)

    2010-12-15

    Research highlights: {yields} Linear friction welding is a feasible process for joining AISI316L. {yields} Most welds had tensile strengths superior to the parent material. {yields} Welding parameters had a significant impact on weld microstructure. {yields} Control of microstructure by controlling welding parameters is a process benefit. - Abstract: Linear friction welding is a solid state joining process established as a niche technology for the joining of aeroengine bladed disks. However, the process is not limited to this application, and therefore the feasibility of joining a common engineering austenitic steel, AISI 316L, has been explored. It was found that mechanically sound linear friction welds could be produced in 316L, with tensile properties in most welds exceeding those of the parent material. The mechanical properties of the welds were also found to be insensitive to relatively large changes in welding parameters. Texture was investigated in one weld using high energy synchrotron X-ray diffraction. Results showed a strong {l_brace}1 1 1{r_brace}< 1 1 2 > type texture at the centre of the weld, which is a typical shear texture in face centre cubic materials. Variations in welding parameters were seen to have a significant impact on the microstructures of welds. This was particularly evident in the variation of the fraction of delta ferrite, in the thermo-mechanically affected zone of the welds, with different process parameters. Analysis of the variation in delta ferrite, with different welding parameters, has produced some interesting insights into heat generation and dissipation during the process. It is hoped that a greater understanding of the process could help to make the parameter optimisation process, when welding 316L as well as other materials, more efficient.

  16. Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Ehrnsten, U.; Toivonen, A. [Materials and Structural Integrity, VTT Technical Research Centre of Finland, Kemistintie 3, P.O. Box 1704, FIN-02044 VTT (Finland); Ivanchenko, M.; Nevdacha, V.; Yagozinskyy, Y.; Haenninen, H. [Department of Mechanical Engineering, Helsinki University of Technology Puumiehenkuja 3, P.O. Box 4200, FIN-02015 HUT (Finland)

    2004-07-01

    Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)

  17. Electrochemical behaviour of iron and AISI 304 stainless steel in simulated acid rain solution

    Energy Technology Data Exchange (ETDEWEB)

    Pilic, Zora; Martinovic, Ivana [Mostar Univ. (Bosnia and Herzegovina). Dept. of Chemistry

    2016-10-15

    The growth mechanism and properties of the oxide films on iron and AISI 304 stainless steel were studied in simulated acid rain (pH 4.5) by means of electrochemical techniques and atomic absorption spectrometry. The layer-pore resistance model was applied to explain a potentiodynamic formation of surface oxides. It was found that the growth of the oxide film on iron takes place by the low-field migration mechanism, while that on the stainless steel takes place by the high-field mechanism. Kinetic parameters were determined. Impedance measurements revealed that Fe surface film has no protective properties at the open circuit potential, while the resistance of stainless steel oxide film is very high. The concentration of the metallic ions released into solution and measured by atomic absorption spectroscopy was in accordance with the results obtained from the electrochemical techniques.

  18. Corrosion and microstructural analysis data for AISI 316L and AISI 347H stainless steels after exposure to a supercritical water environment

    Directory of Open Access Journals (Sweden)

    A. Ruiz

    2016-06-01

    Full Text Available This article presents corrosion data and microstructural analysis data of austenitic stainless steels AISI 316L and AISI 347H exposed to supercritical water (25 MPa, 550 °C with 2000 ppb of dissolved oxygen. The corrosion tests lasted a total of 1200 h but were interrupted at 600 h to allow measurements to be made. The microstructural data have been collected in the grain interior and at grain boundaries of the bulk of the materials and at the superficial oxide layer developed during the corrosion exposure.

  19. Physical properties of the AISI 348 L{sup *} austenitic stainless steel; Propriedades fisicas do aco inoxidavel austenitico AISI 348 L{sup *}

    Energy Technology Data Exchange (ETDEWEB)

    Teodoro, Celso Antonio; Lucki, Georgi; Silva, Jose Eduardo Rosa da; Terremoto, Luis Antanio Albiac; Castanheira, Myrthes; Damy, Margaret de Almeida [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: cteodoro@ipen.br

    2005-07-01

    The study of radiation damage in metals and alloys, used as structural materials of nuclear reactors has a strategic meaning in nuclear technology, because it allows the performance evaluation of these materials in working conditions of PWR. For this sake it is necessary to know the detrimental structural changes that occur during fast neutron irradiation. The aim of the present work is to show some strain-stress results of the AISI 348 L{sup *} stainless steel utilized as a structural material of the fuel elements of PWR, in comparison with the AISI 304. (author)

  20. Corrosion and microstructural analysis data for AISI 316L and AISI 347H stainless steels after exposure to a supercritical water environment.

    Science.gov (United States)

    Ruiz, A; Timke, T; van de Sande, A; Heftrich, T; Novotny, R; Austin, T

    2016-06-01

    This article presents corrosion data and microstructural analysis data of austenitic stainless steels AISI 316L and AISI 347H exposed to supercritical water (25 MPa, 550 °C) with 2000 ppb of dissolved oxygen. The corrosion tests lasted a total of 1200 h but were interrupted at 600 h to allow measurements to be made. The microstructural data have been collected in the grain interior and at grain boundaries of the bulk of the materials and at the superficial oxide layer developed during the corrosion exposure.

  1. Effects of X-rays Radiation on AISI 304 Stainless Steel Weldings with AISI 316L Filler Material: A Study of Resistance and Pitting Corrosion Behavior

    Directory of Open Access Journals (Sweden)

    Francisco Javier Cárcel-Carrasco

    2016-04-01

    Full Text Available This article investigates the effect of low-level ionizing radiation, namely X-rays, on the micro structural characteristics, resistance, and corrosion resistance of TIG-welded joints of AISI 304 austenitic stainless steel made using AISI 316L filler rods. The welds were made in two different environments: natural atmospheric conditions and a closed chamber filled with inert argon gas. The influence of different doses of radiation on the resistance and corrosion characteristics of the welds is analyzed. Welded material from inert Ar gas chamber TIG showed better characteristics and lesser irradiation damage effects.

  2. Experimental investigation of the residual stresses of 304L tubular welded joints; Caracterisation des contraintes residuelles sur assemblages soudes tubulaires en acier 304L

    Energy Technology Data Exchange (ETDEWEB)

    Monin, L.; Panier, S.; Hariri, S.; Zakrzewski, D. [Ecole des Mines de Douai, 941, rue Charles Bourseul, BP 10838, 59508 DOUAI Cedex (France); Faidi, C. [EDF-SEPTEN, 12-14, avenue Dutrievoz, 69628 VILLEURBANNE (France)

    2007-07-01

    In the nuclear energy industry, the use of components made of austenitic stainless steel is widely spread, because of its specific thermal properties. The assembly of these pressure vessels and piping by welding processes often requires surface mechanical operations. These operations aim at hardening surfaces and lowering roughness. Nevertheless the main effect of these operations is the occurrence of residual stresses which can have positive or negative effects on the fatigue life. In this study, we focus on the evaluation and relaxation of residual stresses level on AISI 304L austenitic stainless steel tubular welded structures. Some of these rings are base metal rings (which stand as reference), the rest presents a longitudinal and symmetrical Y-weld joint, with or without grinding. Surface residual stresses, and their relaxation, were determined by using the X-ray diffraction method. (authors) [French] L'utilisation de composants en acier inoxydable austenitique, aux proprietes thermiques bien specifiques, est tres courante dans le domaine de la production d'energie nucleaire. Les procedes d'assemblage par soudage de ces equipements sous pression requierent des traitements de parachevement mecanique afin d'ameliorer l'etat de surface et modifier l'etat mecanique en introduisant des contraintes residuelles, qui peuvent avoir une influence sur la duree de vie de la structure. Cette etude porte sur la caracterisation et la relaxation des contraintes residuelles, determinees sur des eprouvettes annulaires specifiques en acier inoxydable austenitique de type 304L, a l'etat brut ou avec des soudures, arasees ou non. La methode de determination utilisee est la diffraction des rayons X. La relaxation de ces contraintes au cours d'essais de fatigue est egalement etudiee. (auteurs)

  3. Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels

    Science.gov (United States)

    Yenilmez, A.; Karakan, M.; Çelik, İ.

    2017-01-01

    Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens' structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.

  4. PARAMETRIC STUDY OF ELECTRICAL DISCHARGE MACHINING OF AISI 304 STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    P. SRINIVASA RAO,

    2010-08-01

    Full Text Available Electrical discharge machining (EDM is widely used process in the production of mould / dies, aerospace, automobile and electronics industries where intricate complex shapes need to be machined in very hard materials. The selection of the AISI 304 stainless steel was made taking into account its use in almost all industrial applicationsfor approximately 50% of the world’s stainless steel production and consumption. In this work, a study has been carried out on the influence of four design factors: current, open-circuit voltage, servo and dutycycle over material removal rate, tool wear rate, surface roughness and hardness on the die-sinking electrical discharge machining of AISI 304 stainless steel. This has been done using design of experiments (DOE, which allows us to carry out theabove-mentioned analysis performing a relatively small number of experiments. In this case, a 3*24-1 mixed level factorial design, whose resolution is V, has been selected due to the number of factors considered in the study. The resolution of this mixed factorial design allows us to estimate all the main effects, two-factor interactions and pure quadratic effects of the four design factors selected to perform this study.

  5. Physical and Tribological Properties of Nitrided AISI 316 Stainless Steel Balls

    Directory of Open Access Journals (Sweden)

    Yang Shicai

    2016-01-01

    Full Text Available AISI 316 austenitic stainless steel balls (diameters 5.0 and 12.0 mm, typical hardness 250 HV0.3 and flat samples (20×20×2.0 mm were nitrided by a pulsed glow discharge Ar/N2 plasma. Hardness of the ball surfaces was analysed using Vickers indentation. Thermal stability of the nitrided balls (diameter 12.0 mm was studied using a furnace to heat them in air for 8 hours at temperatures up to 700.0°C and then, after cooling to room temperature, the surface hardness of the heated balls was re-measured. Scanning electron microscopy and X-ray diffraction were used to study the microstructures, composition and phase formation of the nitrided sublayers. Unlubricated pin-on-disc wear testing was used to evaluate the wear resistance of nitrided stainless steel balls (5.0 mm diameter and the results were compared with similar testing on hardened Cr-Steel balls (5 mm diameter with hardness of about 650 HV0.3. All the test results indicated that the nitrided AISI 316 austenitic stainless steel balls have advantages over the hardened Cr-Steel balls in terms of retaining high hardness after heat treatment and high resistance to sliding wear at room temperature under higher counterpart stress. These properties are expected to be beneficial for wide range of bearing applications.

  6. Pitting and Intergranular Corrosion Resistance of AISI Type 301LN Stainless Steels

    Science.gov (United States)

    Ningshen, S.; Kamachi Mudali, U.

    2010-03-01

    The pitting and intergranular corrosion (IGC) resistance of AISI type 301LN stainless steels were evaluated using ASTM methods, anodic polarization, and electrochemical impedance techniques. The IGC results indicated that the microstructure of the samples after sensitization heat treatment at 675 °C for 1 h shows step or dual structure for both imported and indigenous materials indicating insignificant Cr23C6 precipitation. The results of immersion tests in boiling 6% copper sulfate + 16% sulfuric acid + copper solution for 24 h followed by the bend test (ASTM A262 Practice-E method) indicated no crack formation in any of the tested specimens. Pitting corrosion resistance carried out in 6% FeCl3 solution at different temperatures of 22 ± 2 and 50 ± 2 °C (ASTM G 48) up to the period of 72 h revealed pitting corrosion attack in all the investigated alloys. The potentiodynamic anodic polarization results in 0.5 M NaCl revealed variation in passive current density and pitting potential depending on the alloy chemistry and metallurgical condition. The passive film properties studied by electrochemical impedance spectroscopy (EIS) correlated well with the polarization results. The x-ray diffraction (XRD) results revealed the presence of austenite (γ) and martensite (α') phases depending on the material condition. The suitability of three indigenously developed AISI type 301LN stainless steels were compared with imported type 301LN stainless steel and the results are highlighted in this article.

  7. Estimation of embrittlement during aging of AISI 316 stainless steel TIG welds

    Indian Academy of Sciences (India)

    J Nayak; K R Udupa; K R Hebbar; H V S Nayak

    2004-12-01

    Weldments of AISI grade 316 stainless steel, having a ferrite content of 4–6% and a variety of nitrogen concentrations were prepared using a modified element implant technique. Charpy impact specimens prepared from these weldments were subjected to a variety of aging treatments. Impact toughness decreases with aging time at all aging temperatures. Nitrogen is found to be beneficial to toughness. An empirical relation connecting the aging temperature, aging time and nitrogen content with toughness has been developed which can be used to estimate the time for embrittlement.

  8. Microstructural changes due to laser surface melting of an AISI 304 stainless steel

    Directory of Open Access Journals (Sweden)

    d?Oliveira A.S.C.M.

    2001-01-01

    Full Text Available Several techniques can be used to improve surface properties. These can involve changes on the surface chemical composition (such as alloying and surface welding processes or on the surface microstructure, such as hardening and melting. In the present work surface melting with a 3kW CO2 cw laser was done to alter surface features of an AISI 304 stainless steel. Microstructure characterisation was done by optical and scanning electron microscopy. Vickers and Knoop microhardness tests evaluated mechanical features after surface melting. Phase transformation during rapid solidification is analysed and discussed.

  9. PITTING CORROSION OF AISI 316Ti STAINLESS STEEL WITH POLISHED SURFACE

    Directory of Open Access Journals (Sweden)

    Viera Zatkalíková

    2010-05-01

    Full Text Available AISI 316Ti is Cr–Ni–Mo austenitic stainless steel with the high Pitting Resistance Equivalent Number (PREN. The effect of the surface finishing by polishing on the pitting corrosion resistance was tested in aggressive 5% FeCl3 solution. The immersion tests were curried out at the temperature 30, 50, 80 °C. The electrochemical cyclic potentiodynamic tests were carried out in the same solution at temperature 30 and 50 °C. The evaluation of the corrosion resistance arose from the comparison of the results of the immersion and the cyclic potentiodynamic tests.

  10. Mechanical Properties of Stellite-6 coated AISI 316L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Pushpinderjit Singh

    2016-01-01

    Full Text Available Present paper describes the mechanical properties of Stellite-6 coated AISI 316 L stainless steel. Specimens were coated using Detonation Gun thermal spray process, with different coating thicknesses of Stellite-6 ranging from 50 µm to 150 µm. Afterwards their properties like tensile strength, impact strength and micro hardness were evaluated on the basis of the results obtained from the experimentation. For comparison of substrate and coated material the graphs were plotted. The coated specimens exhibited superior impact strength and microhardness than that of the bare specimens, whereas the tensile strength of coated specimens decreased marginally with the increase in coating thickness.

  11. Investigating early stages of biocorrosion with XPS: AISI 304 stainless steel exposed to Burkholderia species

    Science.gov (United States)

    Johansson, Leena-Sisko; Saastamoinen, Tuomas

    1999-04-01

    We have investigated the interactions of an exopolymer-producing bacteria, Burkholderia sp. with polished AISI 304 stainless steel substrates using X-ray photoelectron spectroscopy (XPS). Steel coupons were exposed to the pure bacteria culture in a specially designed flowcell for 6 h during which the experiment was monitored in situ with an optical microscope. XPS results verified the formation of biofilm containing extracellular polymer on all the samples exposed to bacteria. Sputter results indicated that some ions needed for metabolic processes were trapped within the biofilm. Changes in the relative Fe concentration and Fe 2p peak shape indicated that also iron had accumulated into the biofilm.

  12. Austenitic Stainless Steel AISI 316L Corrosion Test Research%奥氏体不锈钢AISI 316L腐蚀试验研究

    Institute of Scientific and Technical Information of China (English)

    王金刚; 刘江涛; 程珊珊

    2014-01-01

    在精对苯二甲酸(PTA)生产中,选取干燥机BM302壳体常用材料奥氏体不锈钢AISI 316L为研究对象,在醋酸环境中,对AISI 316L 受Br-及Cl-作用的电化学极化试验和电化学阻抗试验进行腐蚀性试验研究。试验结果表明,Br-或Cl-浓度的增加都会导致AISI 316L不锈钢腐蚀速率增加、击穿电位降低、腐蚀反应电阻减小,导致其耐腐蚀性能下降,腐蚀加剧。为PTA设备腐蚀的现场监测和设备维护提供参考依据。%In purified terephthalic acid (PTA) production, selected the drying machine BM302 shell commonly use material austenitic stainless steel AISI 316L as the research object. In the acetic acid environment, for corrosive test research of AISI 316L, through Br-and Cl-the role of electrochemical polarization test and electrochemical impedance test. The test results show that Br-or Cl-will lead to the increasing of the concentration of seawater AISI 316L stainless steel corrosion rate increase, breakdown voltage is reduced, and the corrosion reaction resistance decreases, and lead to its corrosion resistance drop, corrosion intensifies. That will provide reference for PTA equipment corrosion field monitoring and equipment maintenance.

  13. Effects of cold working on the pitting corrosion behavior s of AISI 304 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kee Min; Kim, Jong Soo; Kim, Young Jun; Kwon, Houk Sang [KAIST, Daejon (Korea, Republic of)

    2015-12-15

    These microstructural changes by cold working can lead improvement of mechanical properties, however from a corrosion resistant point of view, the effects of cold working on the corrosion resistance of stainless steel have been argued. Several studies has been focused on the influence of cold working on the localized corrosion resistance of stainless steels. However, the opinions about the role of cold working on the localized corrosion resistance are highly in consistence. Some studies report that the pitting potential of austenitic stainless steels decreased with cold working level, on the other hands, other studies claimed that the pitting resistance was increased by cold working. Therefore it is necessary to verify how cold working affects pitting corrosion behavior of austenitic stainless steels. In the present work, the influence of cold working on the localized corrosion of AISI 304stainless steel in the neutral chloride solution was studied based on point defect model (PDM). The fraction of deformation-induced martensite was linearly increased with cold rolling level. Through cold rolling, the pitting potential was decreased, the metastable pitting event density was significantly increased and the repassivation potential was decreased. The overall localized corrosion resistance was decreased with cold working, however cold working level increased from 30 % to 50 %, localized corrosion resistance was recovered. The accumulated cation vacancy generates a void at metal/film interface, therefore film breakdown accelerates for cold worked alloys.

  14. Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

    Science.gov (United States)

    Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

    2015-12-01

    The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

  15. Martensitic Transformation during Fatigue Testing of an AISI 301LN Stainless Steel

    Science.gov (United States)

    Mateo, A.; Fargas, G.; Zapata, A.

    2012-02-01

    The plastic deformation accumulated during fatigue testing can induce the transformation of austenite to martensite in metastable austenitic stainless steels. To analyze this issue, a metastable austenitic stainless steel grade AISI 301 LN was studied in two different conditions, i.e. annealed and cold rolled. In the first case, the steel was fully austenitic, whereas cold rolled material had almost 30% of martensite. High cycle fatigue tests at a stress ratio of 0.8 were carried out on flat specimens from both steel conditions. Several characterization techniques, including optical microscopy, X-ray diffraction (XRD) and electron back scattered diffraction (EBSD), were used to detect and quantify the martensite induced by the cyclic deformation.

  16. Microstructure and Properties of Plasma Source Nitrided AISI 316 Austenitic Stainless Steel

    Science.gov (United States)

    Li, G. Y.; Lei, M. K.

    2016-11-01

    Plasma source nitriding is a relatively new nitriding technology which can overcome those inherent shortcomings associated with conventional direct current plasma nitriding technology such as the arcing surface damage, the edging effect and the hollow cathode effect. There is considerable study on the properties of nitrided samples for laboratorial scale plasma source nitriding system; however, little information has been reported on the industrial-scale plasma source nitriding system. In this work, AISI 316 austenitic stainless steel samples were nitrided by an industrial-scale plasma source nitriding system at various nitriding temperatures (350, 400, 450 and 500 °C) with a floating potential. A high-nitrogen face-centered-cubic phase (γN) formed on the surface of nitrided sample surface. As the nitriding temperature was increased, the γN phase layer thickness increased, varying from 1.5 μm for the lowest nitriding temperature of 350 °C, to 30 μm for the highest nitriding temperature of 500 °C. The maximum Vickers microhardness of the γN phase layer with a peak nitrogen concentration of 20 at.% is about HV 0.1 N 15.1 GPa at the nitriding temperature of 450 °C. The wear and corrosion experimental results demonstrated that the γN phase was formed on the surface of AISI 316 austenitic stainless steel by plasma source nitriding, which exhibits not only high wear resistance, but also good pitting corrosion resistance.

  17. Performance analysis of a pneumatic to servo converted system for electrode actuation in resistance spot welding using 304L austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    Nachimani Charde

    2016-01-01

    A high current, AC waveform controller with C-type body frame of spot welder (75 kVA), was examined for the electrode actuating system whose pneumatically driven system has been redesigned and refitted for the servo based system without any vertical spring assistance in the 50 mm movable distance. Moreover, the pressing mechanism was carefully handled during the entire pressing tasks as to ensure that no catastrophic reaction happens for the electrodes’ caps, electrodes’ holders as well as the other part of mechanical assembly. With the mechanically originated-pneumatic and also the converted-servo systems, the stainless steels are welded for both systems to characterize the improvements. While the welding processes were carried out, the electrical signals have been captured to compute the signals’ representation of entire sequences. Later, the welded samples were underwent the tensile shear test, metallurgical observation and hardness test. The analytical results show distinct changes in the force profiles which has led to profound changes in mechanical properties of welded specimens.

  18. The effect of cladding speed on phase constitution and properties of AISI 431 stainless steel laser deposited coatings

    NARCIS (Netherlands)

    Hemmati, I.; Ocelik, V.; De Hosson, J. Th. M.

    2011-01-01

    Shorter processing time has given impetus to laser cladding technology and therefore in this research the AISI 431 martensitic stainless steel coatings are laser deposited at high cladding speeds, i.e. up to 117 mm/s. The analysis of phase constitution and functional properties of the coatings are p

  19. Extended X-Ray Absorption Fine Structure Investigation of Carbon Stabilized Expanded Austenite and Carbides in Stainless Steel AISI 316

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas; Ståhl, Kenny;

    2011-01-01

    Low temperature carburized AISI 316 stainless steel - carbon expanded austenite - was investigated with EXAFS and synchrotron diffraction together with synthesized carbides of the type M3C2, M7C3 and M23C6. It was found that the chemical environment of carbon expanded austenite is not associated ...

  20. Tribological Properties of Nanometric Atomic Layer Depositions Applied on AISI 420 Stainless Steel

    Directory of Open Access Journals (Sweden)

    E. Marin

    2013-09-01

    Full Text Available Atomic Layer Deposition ( ALD is a modern technique that Allows to deposit nanometric, conformal coatings on almost any kind of substrates, from plastics to ceramic, metals or even composites. ALD coatings are not dependent on the morphology of the substrate and are only regulated by the composition of the precursors, the chamber temperature and the number of cycles. In this work, mono- and bi -layer nanometric, protective low-temperature ALD Coatings, based on Al2O3 and TiO2 were applied on AISI 420 Stainless Steel in orderto enhance its relatively low corrosion resistance in chloride containing environments. Tribological testing were also performed on the ALD coated AISI 420 in order to evaluate the wear and scratch resistance of these nanometric layers and thus evaluate their durability. Scratch tests were performed using a standard Rockwell C indenter, under a variable load condition, in order to evaluate the critical loading condition for each coating. Wear testing were performed using a stainless steel counterpart, in ball-on-discconfiguration, in order to measure the friction coefficient and wear to confront the resistance. All scratch tests scars and wear tracks were then observed by means of Scanning Electron Microscopy (SEM in order to understand the wear mechanisms that occurred on the sample surfaces. Corrosion testing, performed under immersion in 0.2 M NaCl solutions, clearly showed that the ALD coatings have a strong effect in protecting the Stainless Steel Substrate against corrosion, reducing the corrosion current density by two orders of magnitude.Tribological The preliminary results showed that ALD depositions obtained at low Temperatures have a brittle behavior caused by the amorphous nature of their structure, and thus undergo delamination phenomena during Scratch Testing at relatively low applied loads. During ball-on-disc testing, the coatings were removed from the substrate, in particular for monolayer ALD configurations

  1. Welding of Vanadium, Tantalum, 304L and 21-6-9 Stainless Steels, and Titanium Alloys at Lawrence Livermore National Laboratory using a Fiber Delivered 2.2 kW Diode Pumped CW Nd:YAG Laser

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, T; Elmer, J; Pong, R; Gauthier, M

    2006-06-16

    This report summarizes the results of a series of laser welds made between 2003 and 2005 at Lawrence Livermore National Laboratory (LLNL). The results are a compilation of several, previously unpublished, internal LLNL reports covering the laser welding of vanadium, tantalum, 304L stainless steel, 21-6-9 (Nitronic 40) steel, and Ti-6Al-4V. All the welds were made using a Rofin Sinar DY-022 diode pumped continuous wave Nd:YAG laser. Welds are made at sharp focus on each material at various power levels and travel speeds in order to provide a baseline characterization of the performance of the laser welder. These power levels are based on measurements of the output power of the laser system, as measured by a power meter placed at the end of the optics train. Based on these measurements, it appears that the system displays a loss of approximately 10% as the beam passes through the fiber optic cable and laser optics. Since the beam is delivered to the fixed laser optics through a fiber optic cable, the effects of fiber diameter are also briefly investigated. Because the system utilizes 1:1 focusing optics, the laser spot size at sharp focus generally corresponds to the diameter of the fiber with which the laser is delivered. Differences in the resulting weld penetration in the different materials system are prevalent, with the welds produced on the Nitronic 40 material displaying the highest depths (> 5 mm) and minimal porosity. A Primes focusing diagnostic has also been installed on this laser system and used to characterize the size and power density distribution of the beams as a function of both power and focus position. Further work is planned in which this focusing diagnostic will be used to better understand the effects of changes in beam properties on the resulting weld dimensions in these and other materials systems.

  2. OPTIMIZATION OF SURFACE ROUGHNESS OF AISI 304 AUSTENITIC STAINLESS STEEL IN DRY TURNING OPERATION USING TAGUCHI DESIGN METHOD

    Directory of Open Access Journals (Sweden)

    D. PHILIP SELVARAJ

    2010-09-01

    Full Text Available The present work is concentrated with the dry turning of AISI 304 Austenitic Stainless Steel (ASS. This paper presents the influence of cutting parameters like cutting speed, feed rate and depth of cut on the surface roughness of austenitic stainless steel during dry turning. A plan of experiments based on Taguchi’s technique has been used to acquire the data. An orthogonal array, the signal to noise (S/N ratio and the analysis of variance (ANOVA are employed to investigate the cutting characteristics of AISI 304 austenitic stainless steel bars using TiC and TiCN coated tungsten carbide cutting tool. Finally the confirmation tests that have been carried out to compare the predicted values with the experimental values confirm its effectiveness in the analysis of surface roughness.

  3. An Electrochemical Impedance Study of AISI 321 Stainless Steel in 0.5 M H2SO4

    Directory of Open Access Journals (Sweden)

    A. Fattah-Alhosseini

    2011-01-01

    Full Text Available The electrochemical behavior of passive films formed on AISI 321 has been examined using electrochemical impedance spectroscopy. AISI 321 is characterized by high interfacial impedance, thereby illustrating its high corrosion resistance. Results showed that the interfacial impedance and the polarization resistance initially increase with applied potential, within the low potential. However, at a sufficiently high potential (>0.6 V, the interfacial impedance and the polarization resistance decrease with increasing potential. The impedance data were adequately represented by an equivalent electrical circuit model based on point defect model, which described the behavior of the passive film on stainless steel more satisfactorily than the proposed models.

  4. Corrosion behavior of low energy, high temperature nitrogen ion-implanted AISI 304 stainless steel

    Indian Academy of Sciences (India)

    M Ghorannevis; A Shokouhy; M M Larijani; S H Haji Hosseini; M Yari; A Anvari; M Gholipur Shahraki; A H Sari; M R Hantehzadeh

    2007-01-01

    This work presents the results of a low-energy nitrogen ion implantation of AISI 304 type stainless steel (SS) at a moderate temperature of about 500° C. The nitrogen ions are extracted from a Kauffman-type ion source at an energy of 30 keV, and ion current density of 100 A cm-2. Nitrogen ion concentration of 6 × 1017, 8 × 1017 and 1018 ions cm-2, were selected for our study. The X-ray diffraction results show the formation of CrN polycrystalline phase after nitrogen bombardment and a change of crystallinity due to the change in nitrogen ion concentration. The secondary ion mass spectrometry (SIMS) results show the formation of CrN phases too. Corrosion test has shown that corrosion resistance is enhanced by increasing nitrogen ion concentration.

  5. Stress corrosion cracking of AISI 321 stainless steel in acidic chloride solution

    Indian Academy of Sciences (India)

    Yanliang Huang

    2002-02-01

    The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic chloride solution was studied by slow strain rate (SSR) technique and fracture mechanics method. The fractured surface was characterized by cleavage fracture. In order to clarify the SCC mechanism, the effects of inhibitor KI on SCC behaviour were also included in this paper. A study showed that the inhibition effects of KI on SCC were mainly attributed to the anodic reaction of the corrosion process. The results of strain distribution in front of the crack tip of the fatigue pre-cracked plate specimens in air, in the blank solution (acidic chloride solution without inhibitor KI) and in the solution added with KI measured by speckle interferometry (SPI) support the unified mechanism of SCC and corrosion fatigue cracking (CFC).

  6. Effect of Plasma Nitriding Temperatures on Characteristics of Aisi 201 Austenitic Stainless Steel

    Science.gov (United States)

    Gao, Yuxin; Zheng, Shaomei

    2016-10-01

    Samples of AISI 201 austenitic stainless steel were produced by plasma nitriding at 350∘C, 390∘C, 420∘C, 450∘C and 480∘C for 5h. Systematic characterization of the nitrided layer was carried out in terms of micrograph observations, phase identification, chemical composition depth profiling, surface microhardness measurements and electrochemical corrosion tests. The results show that the surface hardness and the layer thickness increased with increasing temperature. XRD indicated that a single S-phase layer was formed during low temperature (≤420∘C), while Cr2N or CrN phase was formed besides S-phase when nitrided at 450∘C and 480∘C. The specimen treated at 390∘C presents a much enhanced corrosion resistance compared to the untreated substrate. The corrosion resistance deteriorated for samples treated above 450∘C due to the formation of chromium nitrides.

  7. Influence of nitrogen alloying on hydrogen embrittlement in AISI 304-type stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hannula, S.-P.; Hanninen, H.; Tahtinen, S.

    1984-12-01

    Hydrogen embrittlement of AISI 304-type austenitic stainless steels has been studied with special emphasis on the effects of the nitrogen content of the steels. Hydrogen charging was found to degrade the mechanical properties of all the steels studied, as measured by a tensile test. The fracture surfaces of hydrogen charged specimens were brittle cleavage-like whereas the uncharged specimens showed ductile, dimpled fracture. In sensitized materials transgranular cleavage mode of fracture was replaced by an intergranular mode of fracture and the losses of mechanical properties were higher. Nitrogen alloying decreased the hydrogen-induced losses of mechanical properties by increasing the stabilit of austenite. In sensitized steels the stability of austenite and nitrogen content were found to have only a minor effect on hydrogen embrittlement, except when sensitization had caused ..cap alpha..'-martensite transformation at the grain boundaries.

  8. Influence of nitrogen alloying on hydrogen embrittlement in AISI 304-type stainless steels

    Science.gov (United States)

    Hannula, Simo-Pekka; Hänninen, Hannu; Tähtinen, Seppo

    1984-12-01

    Hydrogen embrittlement of AISI 304-type austenitic stainless steels has been studied with special emphasis on the effects of the nitrogen content of the steels. Hydrogen charging was found to degrade the mechanical properties of all the steels studied, as measured by a tensile test. The fracture surfaces of hydrogen charged specimens were brittle cleavage-like whereas the uncharged specimens showed ductile, dimpled fracture. In sensitized materials transgranular cleavage mode of fracture was replaced by an intergranular mode of fracture and the losses of mechanical properties were higher. Nitrogen alloying decreased the hydrogen-induced losses of mechanical properties by increasing the stability of austenite. In sensitized steels the stability of austenite and nitrogen content were found to have only a minor effect on hydrogen embrittlement, except when sensitization had caused α'-martensite transformation at the grain boundaries.

  9. Dynamic fracture toughness and Charpy impact properties of an AISI 403 martensitic stainless steel

    Science.gov (United States)

    Sreenivasan, P. R.; Ray, S. K.; Mannan, S. L.; Rodriguez, P.

    1996-04-01

    Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness ( KId) from the load-time traces obtained in instrumented tests of unprecracked Charpy V-notch (CVN) specimens are considered. The estimated KId values show reasonable agreement with those obtained from instrumented drop-weight and precracked Charpy tests. Also, except in the upper transition and uppershelf regions, the ASME KIR curve is generally conservative (i.e. gives lower KId values) when compared to the above KId estimates. The conservatism of the ASME KIR at the upper transition and uppershelf temperatures needs verification/validation. The lowest KId values estimated at the lower shelf temperatures for the above steel, namely, 33-42 MPa√m are in good agreement with the reported values of 35-50 MPa√m for the same steel in the literature.

  10. Nitrocarburizing of AISI-304 stainless steel using high-voltage plasma immersion ion implantation

    Science.gov (United States)

    Abd El-Rahman, A. M.; Mohamed, S. H.; Ahmed, M. R.; Richter, E.; Prokert, F.

    2009-05-01

    AISI-304 austenitic stainless steel has been nitrocarburized in N 2 and C 2H 2 ambient using high-voltage plasma immersion ion implantation (PIII) technology. The use of different PIII treatment times revealed important hints with respect to the microstructural, mechanical and corrosion properties of the nitrocarburized layer. Grazing incidence X-ray diffraction (GIXRD) shows the presence of nitride ( γN and CrN) and carbide ( γC and Fe 3C) phases. Glow discharge optical spectroscopy (GDOS) has been used to characterize the elemental depth profiles in which the thickness of the modified layers is derived. Dynamic microindentation method is used for the study of mechanical performance of the nitrocarburized layer as well as the untreated material. The microhardness has been increased to a maximum value of more than nine times compared to that of the untreated one. The corrosion performance is characterized by potentiodynamic polarization technique and was found to be treatment time dependent.

  11. Effect of Hydrogen and Strain-Induced Martensite on Mechanical Properties of AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Sang Hwan Bak

    2016-07-01

    Full Text Available Plastic deformation and strain-induced martensite (SIM, α′ transformation in metastable austenitic AISI 304 stainless steel were investigated through room temperature tensile tests at strain rates ranging from 2 × 10−6 to 2 × 10−2/s. The amount of SIM was measured on the fractured tensile specimens using a feritscope and magnetic force microscope. Elongation to fracture, tensile strength, hardness, and the amount of SIM increased with decreasing the strain rate. The strain-rate dependence of RT tensile properties was observed to be related to the amount of SIM. Specifically, SIM formed during tensile tests was beneficial in increasing the elongation to fracture, hardness, and tensile strength. Hydrogen suppressed the SIM formation, leading to hydrogen softening and localized brittle fracture.

  12. Effect of Carbon and Nitrogen Content on Deformation and Fracture of AISI 304 Austenitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    C. Menapace

    2008-04-01

    Full Text Available The effect of small differences in the content of carbon and nitrogen on the room temperature tensile deformation and fracture behaviour of an AISI 304 stainless steel was studied. In the steel containing the lower amount of carbon and nitrogen, a higher amount of strain induced alfa’ martensite is formed, which increases strain hardening rate and both uniform and total elongation at fracture. The presence of large martensitic areas in the cross section causes strain localization at the austenite/martensite interface, which promotes the nucleation of cracks and their propagation along the interface. This results in a decrease of Ultimate Tensile Strength. Strain induced transformation slightly reduces strain rate sensitivity, as well.

  13. Surface Modification by Nitrogen Plasma Immersion Ion Implantation on Austenitic AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Miguel CASTRO-COLIN; William DURRER; Jorge ALPEZ; Enrique RAMIREZ-HOMS

    2016-01-01

    Surfaces of AISI 304 austenitic stainless steel plates nitrided by plasma immersion ion implantation (PIII) technology were studied by means of Auger electron spectroscopy (AES)and X-ray photoelectron spectroscopy (XPS)to determine the effect of the nitriding process on the surface and subjacent layers.Elemental compositions obtained by AES and XPS at varying depths indicate that the saturation of N is relatively constant as a function of depth,indicating the reliability of PIII technology for subsurface saturation.It is concluded that the concentrations of both Cr and O increase with depth,the subjacent oxide is driven by the Ar+ sputtering process used to access the lower layers,and then N is bound to Cr.

  14. Analysis of deformation induced martensite in AISI 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Jagarinec, Darko; Kirbis, Peter; Predan, Jozef; Vuherer, Tomaz; Gubeljak, Nenad [Maribor Univ. (Slovenia). Faculty of Mechanical Engineering

    2016-08-01

    Metastable austenite stainless steel AISI 316L is sensitive to cold deformation, where transformation from austenite to martensite occurred. The bending deformation as the formation process leads to tensile and compression throughout the thickness of the billet. Tensile testing of the specimen causes differences in the true stress-strain along the contraction neck prior to fracture as well. The aim of the paper is to find correlation between microhardness as brief inspection parameters and extension of martensitic transformation. The total equivalent plastic strain extend diagram obtained by numerical simulation of bending was compared with tensile true stress-strain diagram. Results show very good correlation between hardness, true strain and martesite content. Therefore, one can conclude that by hardness measurement, it is possible to measure the level of equivalent plastic strain until ultimate tensile stress as a linear correlation between hardness, true strain and martesite content.

  15. An investigation of the aseptic loosening of an AISI 316L stainless steel hip prosthesis.

    Science.gov (United States)

    Godec, Matjaz; Kocijan, Aleksandra; Dolinar, Drago; Mandrino, Djordje; Jenko, Monika; Antolic, Vane

    2010-08-01

    The total replacement of joints by the implantation of permanently indwelling prosthetic components has been one of the major successes of modern surgery in terms of relieving pain and correcting deformity. However, the aseptic loosening of a prosthetic-joint component is the most common reason for joint-revision surgery. Furthermore, it is thought that wear particles are one of the major contributors to the development and perpetuation of aseptic loosening. The aim of the present study was to identify the factors related to the aseptic loosening of an AISI 316L stainless steel total hip prosthesis. The stem was evaluated by x-ray photoelectron spectroscopy, with polished and rough regions being analyzed in order to establish the differences in the chemical compositions of both regions. Specific areas were examined using scanning electron microscopy with energy dispersive x-ray spectroscopy and light microscopy.

  16. Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

    Directory of Open Access Journals (Sweden)

    D. Klobčar

    2016-10-01

    Full Text Available The paper presents the effects of flux assisted tungsten inert gas (A-TIG welding of 4 (10 mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304 in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding and A-TIG welding was done. The A-TIG welds were subjected to bending test. A comparative study of TIG and A-TIG welding shows that A-TIG welding increases the weld penetration depth.

  17. Microstructure and Hardness of High Temperature Gas Nitrided AISI 420 Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Ibrahim Nor Nurulhuda Md.

    2014-07-01

    Full Text Available This study examined the microstructure and hardness of as-received and nitrided AISI 420 martensitic stainless steels. High temperature gas nitriding was employed to treat the steels at 1200°C for one hour and four hours using nitrogen gas, followed by furnace cooled. Chromium nitride and iron nitride were formed and concentrated at the outmost surface area of the steels since this region contained the highest concentration of nitrogen. The grain size enlarged at the interior region of the nitrided steels due to nitriding at temperature above the recrystallization temperature of the steel and followed by slow cooling. The nitrided steels produced higher surface hardness compared to as-received steel due to the presence of nitrogen and the precipitation of nitrides. Harder steel was produced when nitriding at four hours compared to one hour since more nitrogen permeated into the steel.

  18. Effect of the purging gas on properties of Ti stabilized AISI 321 stainless steel TIG welds

    Energy Technology Data Exchange (ETDEWEB)

    Taban, Emel; Kaluc, Erdinc; Aykan, T. Serkan [Kocaeli Univ. (Turkey). Dept. of Mechanical Engineering

    2014-07-01

    Gas purging is necessary to provide a high quality of stainless steel pipe welding in order to prevent oxidation of the weld zone inside the pipe. AISI 321 stabilized austenitic stainless steel pipes commonly preferred in refinery applications have been welded by the TIG welding process both with and without the use of purging gas. As purging gases, Ar, N{sub 2}, Ar + N{sub 2} and N{sub 2} + 10% H{sub 2} were used, respectively. The aim of this investigation is to detect the effect of purging gas on the weld joint properties such as microstructure, corrosion, strength and impact toughness. Macro sections and microstructures of the welds were investigated. Chemical composition analysis to obtain the nitrogen, oxygen and hydrogen content of the weld root was done by Leco analysis. Ferrite content of the beads including root and cap passes were measured by a ferritscope. Vickers hardness (HV10) values were obtained. Intergranular and pitting corrosion tests were applied to determine the corrosion resistance of all welds. Type of the purging gas affected pitting corrosion properties as well as the ferrite content and nitrogen, oxygen and hydrogen contents at the roots of the welds. Any hot cracking problems are not predicted as the weld still solidifies with ferrite in the primary phase as confirmed by microstructural and ferrite content analysis. Mechanical testing showed no significant change according to the purge gas. AISI 321 steel and 347 consumable compositions would permit use of nitrogen rich gases for root shielding without a risk of hot cracking.

  19. High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

    Energy Technology Data Exchange (ETDEWEB)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id; Syarif, Dani Gustaman, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia)

    2014-03-24

    The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

  20. Investigation of the influential parameters of machining of AISI 304 stainless steel

    Indian Academy of Sciences (India)

    R A Mahdavinejad; S Saeedy

    2011-12-01

    Austenitic stainless steels are hard materials to machine, due to their high strength, high ductility and low thermal conductivity. The last characteristic results in heat concentration at the tool cutting edge. This paper aims to optimize turning parameters of AISI 304 stainless steel. Turning tests have been performed in three different feed rates (0.2, 0.3, 0.4 mm/rev) at the cutting speeds of 100, 125, 150, 175 and 200 m/min with and without cutting fluid. A design of experiments (DOE) and an analysis of variance (ANOVA) have been made to determine the effects of each parameter on the tool wear and the surface roughness. It is being inferred that cutting speed has the main influence on the flank wear and as it increases to 175 m/min, the flank wear decreases. The feed rate has the most important influence on the surface roughness and as it decreases, the surface roughness also decreases. Also, the application of cutting fluid results in longer tool life and better surface finish.

  1. Surface Nanostructure Formations in an AISI 316L Stainless Steel Induced by Pulsed Electron Beam Treatment

    Directory of Open Access Journals (Sweden)

    Yang Cai

    2015-01-01

    Full Text Available High current pulsed electron beam (HCPEB is an efficient technique for surface modifications of metallic materials. In the present work, the formations of surface nanostructures in an AISI 316L stainless steel induced by direct HCPEB treatment and HCPEB alloying have been investigated. After HCPEB Ti alloying, the sample surface contained a mixture of the ferrite and austenite phases with an average grain size of about 90 nm, because the addition of Ti favors the formation of ferrite. In contrast, electron backscattered diffraction (EBSD analyses revealed no structural refinement on the direct HCPEB treated sample. However, transmission electron microscope (TEM observations showed that fine cells having an average size of 150 nm without misorientations, as well as nanosized carbide particles, were formed in the surface layer after the direct HCPEB treatment. The formation of nanostructures in the 316L stainless steel is therefore attributed to the rapid solidification and the generation of different phases other than the steel substrate in the melted layer.

  2. Effect of Austenitizing Heat Treatment on the Microstructure and Hardness of Martensitic Stainless Steel AISI 420

    Science.gov (United States)

    Barlow, L. D.; Du Toit, M.

    2012-07-01

    The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 °C, followed by oil quenching. The as-quenched microstructures were found to range from almost fully martensitic structures to martensite with up to 35% retained austenite after quenching, with varying amounts of carbides. Optical and scanning electron microscopy was used to characterize the microstructures, and X-ray diffraction was employed to identify the carbide present in the as-quenched structures and to quantify the retained austenite contents. Hardness tests were performed to determine the effect of heat treatment on mechanical properties. As-quenched hardness values ranged from 700 to 270 HV, depending on the amount of retained austenite. Thermodynamic predictions (using the CALPHAD™ model) were employed to explain these microstructures based on the solubility of the carbide particles at various austenitizing temperatures.

  3. Electrochemical Study of Welded AISI 304 and 904L Stainless Steel in Seawater in View of Corrosion

    Directory of Open Access Journals (Sweden)

    Richárd Székely

    2010-10-01

    Full Text Available This is a comparative study of the corrosion behaviour of welds in AISI 304 and AISI 904L stainless steels carried out in seawater model solution in the temperature range 5-35°C and the standard of corrosion testing of welds was followed. The corrosion rate and corrosion attack characteristics were determined for welds of the examined steels with several type of treatment. The aim of this work was to compare the steels based on their resistance against the corrosion in terms of pitting potential (Epit and repassivation potential (Erepass. Seawater is an electrochemically aggressive medium, which can initiate localised corrosion in welded stainless steels. Different electrochemical and testing methods were used, including cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy (EIS, pH measuring and penetration tests.

  4. OPTIMIZATION OF SURFACE ROUGHNESS AND TOOL FLANK WEAR IN TURNING OF AISI 304 AUSTENITIC STAINLESS STEEL WITH CVD COATED TOOL

    Directory of Open Access Journals (Sweden)

    M. KALADHAR

    2013-04-01

    Full Text Available AISI 304 austenitic stainless steel is a popularly used grade in the various fields of manufacturing because of its high ductility, high durability and excellent corrosion resistance. High work hardening, low heat conductivity and high built up edge (BUE formation made this as difficult-to- machine material. Poor surface quality and rapid tool wear are the common problems encountered while machining it. In the present work, an attempt has been made to explore the influence of machining parameters on the performance measures, surface roughness and flank wear in turning of AISI 304 austenitic stainless steel with a two layer Chemical vapour deposition(CVD coated tool. In order to achieve this, Taguchi approach has been employed. The results revealed that the cutting speed most significantly, influences both surface roughness and flank wear. In addition to this the optimal setting of process parameters and optimal ranges of performance measures are predicted.

  5. LaCrO3 composite coatings for AISI 444 stainless steel solid oxide fuel cell interconnects

    Directory of Open Access Journals (Sweden)

    Wilson Acchar

    2012-12-01

    Full Text Available Doped lanthanum chromite-based ceramics are the most widely used interconnector material in solid fuel cells (SOFC since they exhibit significant electrical and thermal conductivity, substantial corrosion resistance and adequate mechanical strength at ambient and high temperatures. The disadvantage of this material is its high cost and poor ductility. The aim of this study is to determine the mechanical and oxidation behavior of a stainless steel (AISI 444 with a LaCrO3 deposition on its surface obtained through spray pyrolisis. Coated and pure AISI 444 materials were characterized by mechanical properties, oxidation behavior, X-ray diffraction and scanning electronic microscopy. Results indicated that the coated material displays better oxidation behavior in comparison to pure stainless steel, but no improvement in mechanical strength. Both materials indicate that deformation behavior depends on testing temperatures.

  6. Modification and characterization of the AISI 410 martensitic stainless steels surface; Modificacao e caracterizacao da superficie do aco inoxidavel martensitico AISI 410

    Energy Technology Data Exchange (ETDEWEB)

    Bincoleto, A.V.L. [Universidade Federal de Sao Carlos (PPG-CEM/UFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Nascente, P.A.P. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    Steam turbines are used in the generation of more than half the electric energy produced in the world nowadays. It is important the study which aims to improve the efficiency by means of the optimization of leaks and of the aerodynamic profiles, as well as to maintain the integrity of the components. The martensitic stainless steels are widely employed due to the combination of their good mechanical properties with higher corrosion resistance. However, their lower wear resistance and their poor tribological behavior limit their use, since they decrease the component life time. In order to evaluate the improvement in the performance of the AISI 410 stainless steel, several process of surface modification were employed. Five samples were produced: the first one was not treated, the second one received liquid nitriding, the third, gas nitriding, the forth, thermal aspersion of tungsten carbide, and the fifth, boronizing. The samples were characterized by optical microscopy, surface microhardness, and X-ray diffractometry. (author)

  7. Texture analysis of deformation induced martensite in an AISI 301L stainless steel: microtexture and macrotexture aspects

    OpenAIRE

    Hamilton Ferreira Gomes de Abreu; Marcelo José Gomes da Silva; Luís Flávio Gaspar Herculano; Harry Bhadeshia

    2009-01-01

    Experiments have been conducted to study the strain induced transformation from austenite to martensite in a metastable AISI 301LN austenitic stainless steel, deformed by uniaxial tension applied along rolling direction. Samples deformed 10 and 20% have shown the presence of α´ martensite phase. Measured pole figures of martensite phase were compared to calculated ones, assuming no variant selection and selection of variants where interaction between stress and the plate of martensite ad...

  8. Investigating the correlation between some of the properties of plasma nitrided AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    M. Olzon-Dionysio

    2013-01-01

    Full Text Available When AISI 316L stainless steels are submitted to the nitriding process at temperatures lower than 450 °C, a high nitrogen content expanded austenite phase is formed, which shows higher hardness and higher pitting corrosion resistance compared to the untreated material. As a result, this material becomes adequate for biomedical application. The conditions of the nitriding technique, such as gas mixture, pressure, time and temperature, play an important role in some properties of the modified layer, including: thickness, hardness and N concentration along the layer. This paper explores a set of six samples of AISI 316L, nitrided at different times and temperatures, whose properties show important differences. The aim of this research is to investigate the correlation between the nitrided layer thickness (in the range of 0.77 to 11 µm with both X-ray patterns characteristics and hardness measurements, which used two distinct loads. The results of this study show that: whereas the 3.6 gf load was suitable to measure the real hardness for four of the nitrided layers showing thickness ≥ 2.9 µm, the 50 gf load measured a substrate contribution, probably even for the highest thickness, 11 µm. Moreover, analyzing different reflections of the X-ray patterns showed evidence of the clear consistency between the X-Ray depths and the nitrided layer thicknesses: if the layer thickness is lower than the penetration depth of X-rays, two phases (austenite and expanded substrate are present. If the layer thickness is higher, only the austenite is observed. Finally, concerning the citotoxicity property, all the samples, nitrided or not, were approved in the test for biocompatibility, indicating their potential use for biomedical applications.

  9. OPTIMIZATION OF SURFACE ROUGHNESS OF AISI 304 AUSTENITIC STAINLESS STEEL IN DRY TURNING OPERATION USING TAGUCHI DESIGN METHOD

    OpenAIRE

    D. PHILIP SELVARAJ; Chandramohan, P.

    2010-01-01

    The present work is concentrated with the dry turning of AISI 304 Austenitic Stainless Steel (ASS). This paper presents the influence of cutting parameters like cutting speed, feed rate and depth of cut on the surface roughness of austenitic stainless steel during dry turning. A plan of experiments based on Taguchi’s technique has been used to acquire the data. An orthogonal array, the signal to noise (S/N) ratio and the analysis of variance (ANOVA) are employed to investigate the cutting cha...

  10. Evaluation of structural behaviour and corrosion resistant of austenitic AISI 304 and duplex AISI 2304 stainless steel reinforcements embedded in ordinary Portland cement mortars; Evaluacion del comportamiento estructural y de resistencia a la corrosion de armaduras de acero inoxidable austenitico AISI 304 y duplex AISI 2304 embebidas en morteros de cemento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Medina, E.; Cobo, A.; Bastidas, D. M.

    2012-07-01

    The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304) and duplex EN 1.4362 (AISI 2304) have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR), of reinforcements embedded in ordinary Portland cement (OPC) mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure. (Author) 26 refs.

  11. Investigation of AISI 441 Ferritic Stainless Steel and Development of Spinel Coatings for SOFC Interconnect Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhenguo; Xia, Guanguang; Wang, Chong M.; Nie, Zimin; Templeton, Joshua D.; Singh, Prabhakar; Stevenson, Jeffry W.

    2008-05-30

    As part of an effort to develop cost-effective ferritic stainless steel-based interconnects for solid oxide fuel cell (SOFC) stacks, both bare and spinel coated AISI 441 were studied in terms of metallurgical characteristics, oxidation behavior, and electrical performance. The conventional melt metallurgy used for the bulk alloy fabrication leads to significant processing cost reduction and the alloy chemistry with the presence of minor alloying additions of Nb and Ti facilitate the strengthening by precipitation and formation of Laves phase both inside grains and along grain boundaries during exposure in the intermediate SOFC operating temperature range. The Laves phase formed along the grain boundaries also ties up Si and prevents the formation of an insulating silica layer at the scale/metal interface during prolonged exposure. The substantial increase in ASR during long term oxidation due to oxide scale growth suggested the need for a conductive protection layer, which could also minimize Cr evaporation. In particular, Mn1.5Co1.5O4 based surface coatings on planar coupons drastically improved the electrical performance of the 441, yielding stable ASR values at 800ºC for over 5,000 hours. Ce-modified spinel coatings retained the advantages of the unmodified spinel coatings, and also appeared to alter the scale growth behavior beneath the coating, leading to a more adherent scale. The spinel protection layers appeared also to improve the surface stability of 441 against the anomalous oxidation that has been observed for ferritic stainless steels exposed to dual atmosphere conditions similar to SOFC interconnect environments. Hence, it is anticipated that, compared to unmodified spinel coatings, the Ce-modified coatings may lead to superior structural stability and electrical performance.

  12. Microstructure analysis of AISI 304 stainless steel produced by twin-roll thin strip casting process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The microstructure of AISI 304 austenite stainless steel fabricated by the thin strip casting process were investigated using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD).The microstructures of the casting strips show a duplex structure consisting of delta ferrite and austenite. The volume fraction of the delta ferrite is about 9.74vol% at the center and 6.77vol% at the surface of the casting thin strip, in vermicular and band shapes. On account of rapid cooling and solidification in the continuous casting process, many kinds of inclusions and precipitates have been found. Most of the inclusions and precipitates are spherical complex compounds consisting of oxides, such as, SiO2, MnO, Al2O3,Cr2O3,and FeO or their multiplicity oxides of MnO·Al2O3,2FeO·SiO2, and 2MnO·SiO2. Many defects including dislocations and stacking faults have also formed during the rapid cooling and solidification process, which is helpful to improve the mechanical properties of the casting strips.

  13. Thermodynamic modeling and kinetics simulation of precipitate phases in AISI 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y., E-mail: yangying@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Busby, J.T. [Fusion and Materials for Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2014-05-01

    This work aims at utilizing modern computational microstructural modeling tools to accelerate the understanding of phase stability in austenitic steels under extended thermal aging. Using the CALPHAD approach, a thermodynamic database OCTANT (ORNL Computational Thermodynamics for Applied Nuclear Technology), including elements of Fe, C, Cr, Ni, Mn, Mo, Si, and Ti, has been developed with a focus on reliable thermodynamic modeling of precipitate phases in AISI 316 austenitic stainless steels. The thermodynamic database was validated by comparing the calculated results with experimental data from commercial 316 austenitic steels. The developed computational thermodynamics was then coupled with precipitation kinetics simulation to understand the temporal evolution of precipitates in austenitic steels under long-term thermal aging (up to 600,000 h) at a temperature regime from 300 to 900 °C. This study discusses the effect of dislocation density and difusion coefficients on the precipitation kinetics at low temperatures, which shed a light on investigating the phase stability and transformation in austenitic steels used in light water reactors.

  14. Finite Element Simulation of Residual Stresses in Butt Welding of Two AISI 304 Stainless Steel Plates

    Directory of Open Access Journals (Sweden)

    Gurinder Singh Brar

    2013-06-01

    Full Text Available Welding is one of the most reliable and efficient permanent metal joining processes in the industry. When two plates are joined by welding, a very complex thermal cycle is applied to the weldment. Thermal energy applied results in irreversible elastic-plastic deformation and consequently gives rise to the residual stresses in and around fusion zone and heat affected zone (HAZ. It is well established fact that structural integrity of components is substantially affected by the residual stresses when subjected to thermal and structural loads. Presence of residual stresses may be beneficial or harmful for the structural components depending on the nature and magnitude of residual stresses. Using finite element based commercially available software, coupled thermal-mechanical three dimensional finite element model was developed by making an approximate geometry of the butt welded joint. Finite element analysis was performed to understand the complete nature of residual stresses in manual metal arc welded joint of AISI 304 stainless steel plate. Variation of residual stress in the plates in the heat affected zone was also being studied. The results obtained by finite element method agree well with those from X-ray diffraction method as published in literature for the prediction of residual stresses.

  15. Parametric optimization during machining of AISI 304 Austenitic Stainless Steel using CVD coated DURATOMIC cutting insert

    Directory of Open Access Journals (Sweden)

    M. Kaladhar

    2012-08-01

    Full Text Available In this work, Taguchi method is applied to determine the optimum process parameters for turning of AISI 304 austenitic stainless steel on CNC lathe. A Chemical vapour deposition (CVD coated cemented carbide cutting insert is used which is produced by DuratomicTM technology of 0.4 and 0.8 mm nose radii. The tests are conducted at four levels of Cutting speed, feed and depth of cut. The influence of these parameters are investigated on the surface roughness and material removal rate (MRR. The Analysis Of Variance (ANOVA is also used to analyze the influence of cutting parameters during machining. The results revealed that cutting speed significantly (46.05% affected the machined surface roughness values followed by nose radius (23.7%. The influence of the depth of cut (61.31% in affecting material removal rate (MRR is significantly large. The cutting speed (20.40% is the next significant factor. Optimal range and optimal level of parameters are also predicted for responses.

  16. Influence of gas pressure and substrate temperature on PIII nitrocarburizing process of AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Rahman, A.M. [Physics Department, Faculty of Science, South Valley University, Sohag Branch, Sohag (Egypt) and Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany)]. E-mail: ahmedphys96@hotmail.com; El-Hossary, F.M. [Physics Department, Faculty of Science, South Valley University, Sohag Branch, Sohag (Egypt); Negm, N.Z. [Physics Department, Faculty of Science, South Valley University, Sohag Branch, Sohag (Egypt); Prokert, F. [Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany); Richter, E. [Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany); Moeller, W. [Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany)

    2004-12-01

    Plasma immersion ion implantation (PIII) has been used to modify the surface properties of 304 austenitic stainless steel (AISI). The influence of working gas pressure, 0.2-1.0 Pa, and substrate temperature, 300-500 deg. C, on the microstructure, treating rate, nitrogen/carbon concentration depth profile, and surface microhardness was investigated. A gas composition of 25% C{sub 2}H{sub 2}, 75% N{sub 2}, r.f. plasma power input of 350 W, and a negatively biased potential of 30 kV were fixed during the experiment. The experimental results show that the substrate temperature and the diffusion process of nitrogen and carbon depend on the gas pressure inside the plasma chamber. The thickness of the modified layer has been found to be more than 30 {mu}m for samples were treated in the plasma for 60 min. The results show also that the values of diffusion coefficient and surface microhardness of the treated samples are high to be 3.4 x 10{sup -1} {mu}m{sup 2}/s and 1880 kg/mm{sup 2}, respectively.

  17. Influence of gas pressure and substrate temperature on PIII nitrocarburizing process of AISI 304 stainless steel

    Science.gov (United States)

    Abd El-Rahman, A. M.; El-Hossary, F. M.; Negm, N. Z.; Prokert, F.; Richter, E.; Möller, W.

    2004-12-01

    Plasma immersion ion implantation (PIII) has been used to modify the surface properties of 304 austenitic stainless steel (AISI). The influence of working gas pressure, 0.2-1.0 Pa, and substrate temperature, 300-500 °C, on the microstructure, treating rate, nitrogen/carbon concentration depth profile, and surface microhardness was investigated. A gas composition of 25% C2H2, 75% N2, r.f. plasma power input of 350 W, and a negatively biased potential of 30 kV were fixed during the experiment. The experimental results show that the substrate temperature and the diffusion process of nitrogen and carbon depend on the gas pressure inside the plasma chamber. The thickness of the modified layer has been found to be more than 30 μm for samples were treated in the plasma for 60 min. The results show also that the values of diffusion coefficient and surface microhardness of the treated samples are high to be 3.4 × 10-1 μm2/s and 1880 kg/mm2, respectively.

  18. Nitrocarburizing of AISI-304 stainless steel using high-voltage plasma immersion ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Rahman, A.M. [Physics Department, Faculty of Science, Sohag University, 82524 Sohag (Egypt)], E-mail: ahmedphys96@hotmail.com; Mohamed, S.H.; Ahmed, M.R. [Physics Department, Faculty of Science, Sohag University, 82524 Sohag (Egypt); Richter, E.; Prokert, F. [Institut fuer Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden Rossendorf (Germany)

    2009-05-15

    AISI-304 austenitic stainless steel has been nitrocarburized in N{sub 2} and C{sub 2}H{sub 2} ambient using high-voltage plasma immersion ion implantation (PIII) technology. The use of different PIII treatment times revealed important hints with respect to the microstructural, mechanical and corrosion properties of the nitrocarburized layer. Grazing incidence X-ray diffraction (GIXRD) shows the presence of nitride ({gamma}{sub N} and CrN) and carbide ({gamma}{sub C} and Fe{sub 3}C) phases. Glow discharge optical spectroscopy (GDOS) has been used to characterize the elemental depth profiles in which the thickness of the modified layers is derived. Dynamic microindentation method is used for the study of mechanical performance of the nitrocarburized layer as well as the untreated material. The microhardness has been increased to a maximum value of more than nine times compared to that of the untreated one. The corrosion performance is characterized by potentiodynamic polarization technique and was found to be treatment time dependent.

  19. Enhanced mechanical properties of type AISI301LN austenitic stainless steel through advanced thermo mechanical process

    Energy Technology Data Exchange (ETDEWEB)

    Huang Junxia, E-mail: huangjunxia@baosteel.com [Shanghai Baosteel Research Institute, Shanghai 200431 (China); Ye Xiaoning; Gu Jiaqing; Chen Xu [Shanghai Baosteel Research Institute, Shanghai 200431 (China); Xu Zhou [School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer 69% of strain induced martensite were obtained after 80% thickness reduction at 0 Degree-Sign C. Black-Right-Pointing-Pointer The best annealing regime was determined for diffusional controlled reversion. Black-Right-Pointing-Pointer The effect of grain size on mechanical properties conforms with the H-P relationship. - Abstract: The effect of annealing temperature and time on the grain size of reversed austenite and mechanical properties was studied based on AISI301LN austenitic stainless steel in this paper. Cold rolling at 0 Degree-Sign C was employed to obtain the strain-induced martensite, followed by annealing treatment at the temperature range of 650-900 Degree-Sign C for 1-20 min. The relationship between the volume fraction of strain-induced martensite and cold reduction was analyzed by Ferritescope MP30 and X-ray diffraction. The grain growth of reversed austenite was observed by FEG-SEM and the mechanical properties were determined by tensile tests and Vickers hardness tests. Austenite grain sizes under 3 {mu}m can be obtained after annealing in the range of 700-900 Degree-Sign C for 1-20 min. The finest austenite grain size was produced after annealing at 700 Degree-Sign C for 20 min, which had a good combination of yield strength ( Almost-Equal-To 830 MPa), tensile strength ( Almost-Equal-To 953 MPa) and elongation ( Almost-Equal-To 36%).

  20. Welding of AA1050 aluminum with AISI 304 stainless steel by rotary friction welding process

    Directory of Open Access Journals (Sweden)

    Chen Ying An

    2010-09-01

    Full Text Available The purpose of this work was to assess the development of solid state joints of dissimilar material AA1050 aluminum and AISI 304 stainless steel, which can be used in pipes of tanks of liquid propellants and other components of the Satellite Launch Vehicle. The joints were obtained by rotary friction welding process (RFW, which combines the heat generated from friction between two surfaces and plastic deformation. Tests were conducted with different welding process parameters. The results were analyzed by means of tensile tests, Vickers microhardness, metallographic tests and SEM-EDX. The strength of the joints varied with increasing friction time and the use of different pressure values. Joints were obtained with superior mechanical properties of the AA1050 aluminum, with fracture occurring in the aluminum away from the bonding interface. The analysis by EDX at the interface of the junction showed that interdiffusion occurs between the main chemical components of the materials involved. The RFW proves to be a great method for obtaining joints between dissimilar materials, which is not possible by fusion welding processes.

  1. Corrosion of aluminium, stainless steels and AISI 680 nickel alloy in nitrogen-based fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kap, I.; Starostin, M.; Shter, G.E.; Grader, G.S. [Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa (Israel)

    2012-07-15

    Nitrogen-based compounds can potentially be used as alternative non-carbon or low-carbon fuels. Nevertheless, the corrosion of construction materials at high temperatures and pressures in the presence of such fuel has not been reported yet. This work is focused on the corrosion of AISI Al 6061, 1005 carbon steel (CS), 304, 316L, 310 austenitic stainless steels (SS) and 680 nickel alloy in highly concentrated water solution of ammonium nitrate and urea (ANU). The corrosion at 50 C and ambient pressure and at 350 C and 20 bar was investigated to simulate storage and working conditions. Sodium chloride was added to the fuel (0-5 wt%) to simulate industrial fertilizers and accelerated corrosion environment. Heavy corrosion of CS was observed in ANU solution at 50 C, while Al 6061, 304 and 316L SS showed high resistance both to uniform and pitting corrosion in ANU containing 1% of sodium chloride. Addition of 5% sodium chloride caused pitting of Al 6061 but had no influence on the corrosion of SS. Tests in ANU at 350 C and 20 bar showed pitting on SS 304 and 316L and 680 nickel alloy. The highest corrosion resistance was found for SS 310 due to formation of stable oxide film on its surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Martensite transformation induced by deformation and its phase electrochemical behavior for stainless steels AISI 304 and 316L

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The martensite transformation induced by tensile elongation and its effect on the behavior of phase electrochemistry of AISI 304 and 316L in 3.5% NaCl solution were studied. The results show that the content of ((-martensite in stainless steel 304 increases with the true strain. As ((-martensite content increased, free corrosion potential and pitting potential of stainless steel 304 in 3.5% NaCl solution appeared the change trend of a minimum. It was also found that pitting nucleated preferentially at the phase interfaces between martensite and austenite. There existed apparent difference between electrochemical properties of austenite and of martensite for stainless steel 304 and 316L in 3.5% NaCl solution.

  3. Aluminum coating by fluidized bed chemical vapor deposition on austenitic stainless steels AISI 304 and AISI 316

    Directory of Open Access Journals (Sweden)

    Jose Luddey Marulanda-Arevalo

    2015-01-01

    Full Text Available Los revestimientos de aluminio f ueron depositados sobre aceros inoxidables AISI 304 y AISI 316 en el rango de temperatura de 5 60 a 600 °C por deposición química de vapor en lecho fluidizado(CVD – FBR. Se utilizó un lecho que consistía en 10 % de aluminio en polvo y 90 % de lecho inerte (alúmina, el cual fue fluidizado con Ar y como ga ses activadores se utilizó una mezcla de ácido clorhídrico con hidrógeno (HCl/H 2 . En el recubrimiento si n tratamiento térmico están las siguiente s especies: Al 13 Fe 4 , Fe 2 Al 5 , FeAl 2 y Al 5 FeNi, las cuales están presentes para ambos aceros. Además, el tratamiento térmico provoca la difusa de alu minio hacia el sustrato y la difusa de hierro del sustrato haci a la superficie del recubrimiento, haciendo la trans formación de los compuestos ant eriores a FeAl, Fe 2 Al 5 , FeAl 2 , Al 0.99 Fe 0.99 Ni 0.02 , AlNi y el Fe 2 AlCr. Se realizó la simulación termodinámica con el s oftware Thermo Calc para obt ener información de la posible composición y la cantidad de mat erial depositado, para condiciones seleccionadas. Las muestras recubi ertas y sin recubrir, se expus ieron a 750 ºC en una atmósfera d onde el vapor agua se transporta a las muestras usando un flujo de N 2 de 40 ml/min, más 100 % vapor de agua (H 2 O. Los dos sustratos sin revestir se comportaron de manera diferente, ya que el acero AISI 304 soportó bien el a taque y ganó poco peso (0.49 mg/cm 2 , en comparación con el acero AISI 316 que perdió mucho peso (25.4 mg/cm 2 . Los aceros recubiertos ganaron poco de peso durante las mil horas de exposición (0.26 mg/cm 2 y soportaron muy bien el ataque corrosivo en c omparación con sustratos sin r ecubrimiento.

  4. Optimization Of Pulsed Current Parameters To Minimize Pitting Corrosion İn Pulsed Current Micro Plasma Arc Welded Aısı 304l Sheets Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Kondapalli Siva Prasad

    2013-06-01

    Full Text Available Austenitic stainless steel sheets have gathered wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance, such as metal bellows used in expansion joints in aircraft, aerospace and petroleum industry. In case of single pass welding of thinner sections of this alloy, Pulsed Current Micro Plasma Arc Welding (PCMPAW was found beneficial due to its advantages over the conventional continuous current process. This paper highlights the development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to pitting corrosion rates in PCMPAW of AISI 304L sheets in 1 Normal HCl. The experiments were conducted based on a five factor, five level central composite rotatable design matrix. A Genetic Algorithm (GA was developed to optimize the process parameters for minimizing the pitting corrosion rates.

  5. Surface Texturing-Plasma Nitriding Duplex Treatment for Improving Tribological Performance of AISI 316 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Naiming Lin

    2016-10-01

    Full Text Available Surface texturing-plasma nitriding duplex treatment was conducted on AISI 316 stainless steel to improve its tribological performance. Tribological behaviors of ground 316 substrates, plasma-nitrided 316 (PN-316, surface-textured 316 (ST-316, and duplex-treated 316 (DT-316 in air and under grease lubrication were investigated using a pin-on-disc rotary tribometer against counterparts of high carbon chromium bearing steel GCr15 and silicon nitride Si3N4 balls. The variations in friction coefficient, mass loss, and worn trace morphology of the tested samples were systemically investigated and analyzed. The results showed that a textured surface was formed on 316 after electrochemical processing in a 15 wt % NaCl solution. Grooves and dimples were found on the textured surface. As plasma nitriding was conducted on a 316 substrate and ST-316, continuous and uniform nitriding layers were successfully fabricated on the surfaces of the 316 substrate and ST-316. Both of the obtained nitriding layers presented thickness values of more than 30 μm. The nitriding layers were composed of iron nitrides and chromium nitride. The 316 substrate and ST-316 received improved surface hardness after plasma nitriding. When the tribological tests were carried out under dry sliding and grease lubrication conditions, the tested samples showed different tribological behaviors. As expected, the DT-316 samples revealed the most promising tribological properties, reflected by the lowest mass loss and worn morphologies. The DT-316 received the slightest damage, and its excellent tribological performance was attributed to the following aspects: firstly, the nitriding layer had high surface hardness; secondly, the surface texture was able to capture wear debris, store up grease, and then provide continuous lubrication.

  6. Fatigue life improvements of the AISI 304 stainless steel ground surfaces by wire brushing

    Science.gov (United States)

    Ben Fredj, Nabil; Ben Nasr, Mohamed; Ben Rhouma, Amir; Sidhom, Habib; Braham, Chedly

    2004-10-01

    The surface and subsurface integrity of metallic ground components is usually characterized by an induced tensile residual stress, which has a detrimental effect on the fatigue life of these components. In particular, it tends to accelerate the initiation and growth of the fatigue cracks. In this investigation, to deliberately generate compressive residual stresses into the ground surfaces of the AISI 304 stainless steel (SS), wire brushing was applied. It was found that under the experimental conditions selected in this investigation, while the surface roughness was slightly improved by the brushing process, the surface residual stress shifted from a tensile stress (σ‖=+450 MPa) to a compressive stress (σ‖=-435 MPa). On the other hand, the work-hardened deformation layer was almost two times deeper after wire brushing. Concerning the fatigue life, an improvement of 26% in terms of endurance limit at 2×106 cycles was realized. Scanning electron microscope (SEM) observations of the fatigue fracture location and size were carried out to explain the fatigue life improvement. It was found that the enhancement of the fatigue strength could be correlated with the distribution and location of the fatigue fracture nucleation sites. Concerning the ground surfaces, it was seen that the fatigue cracks initiated at the bottom of the grinding grooves and were particularly long (150-200 µm). However, the fatigue cracks at the brushed surfaces were shorter (20-40 µm) and appeared to initiate sideways to the plowed material caused by the wire brushing. The results of the wire-brushed surface characterization have shown that significant advantages can be realized regarding surface integrity by the application of this low-cost process compared to shot peening.

  7. Comparative study of pulsed Nd:YAG laser welding of AISI 304 and AISI 316 stainless steels

    Science.gov (United States)

    Kumar, Nikhil; Mukherjee, Manidipto; Bandyopadhyay, Asish

    2017-02-01

    Laser welding is a potentially useful technique for joining two pieces of similar or dissimilar materials with high precision. In the present work, comparative studies on laser welding of similar metal of AISI 304SS and AISI 316SS have been conducted forming butt joints. A robotic control 600 W pulsed Nd:YAG laser source has been used for welding purpose. The effects of laser power, scanning speed and pulse width on the ultimate tensile strength and weld width have been investigated using the empirical models developed by RSM. The results of ANOVA indicate that the developed models predict the responses adequately within the limits of input parameters. 3-D response surface and contour plots have been developed to find out the combined effects of input parameters on responses. Furthermore, microstructural analysis as well as hardness and tensile behavior of the selected weld of 304SS and 316SS have been carried out to understand the metallurgical and mechanical behavior of the weld. The selection criteria are based on the maximum and minimum strength achieved by the respective weld. It has been observed that the current pulsation, base metal composition and variation in heat input have significant influence on controlling the microstructural constituents (i.e. phase fraction, grain size etc.). The result suggests that the low energy input pulsation generally produce fine grain structure and improved mechanical properties than the high energy input pulsation irrespective of base material composition. However, among the base materials, 304SS depict better microstructural and mechanical properties than the 316SS for a given parametric condition. Finally, desirability function analysis has been applied for multi-objective optimization for maximization of ultimate tensile strength and minimization of weld width simultaneously. Confirmatory tests have been conducted at optimum parametric conditions to validate the optimization techniques.

  8. Formation of amorphous Ti alloy layers by excimer laser mixing of Ti on AISI 304 stainless-steel surfaces

    Science.gov (United States)

    Jervis, T. R.; Nastasi, M.; Zocco, T. G.; Martin, J. A.

    1988-07-01

    We used excimer laser radiation at 308 nm to mix thin layers of Ti into AISI 304 stainless steel. Different numbers of shots at a fluence about twice the threshold for melting varied the amount of mixing. When mixing is sufficiently complete, an amorphous surface layer is formed with Ti substituting for Fe on a one-to-one basis in the alloy. The laser mixing process, unlike Ti ion implantation, does not result in high incorporation of C in the processed layer, although some C from surface and interface contamination is incorporated into the surface layer.

  9. Effect of martensite to austenite reversion on the formation of nano/submicron grained AISI 301 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Karimi, M.; Najafizadeh, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, A., E-mail: ahmad_k@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Eskandari, M. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2009-11-15

    The martensite to austenite reversion behavior of 90% cold rolled AISI 301 stainless steel was investigated in order to refine the grain size. Cold rolled specimens were annealed at 600-900 deg. C, and subsequently characterized by scanning electron microscopy, X-ray diffraction, Feritscope, and hardness measurements. The effects of annealing parameters on the formation of fully-austenitic nano/submicron grained structure and the mechanisms involved were studied. It was found that annealing at 800 deg. C for 10 s exhibited the smallest average austenite grain size of 240 {+-} 60 nm with an almost fully-austenitic structure.

  10. Effect of Cl– on the corrosive wear of AISI 321 stainless steel in H2SO4 solution

    Indian Academy of Sciences (India)

    Yanliang Huang; Xiaoxia Jiang; Sizuo Li

    2003-06-01

    The effect of Cl– on the corrosive wear behaviour of AISI 321 stainless steel in H2SO4 solution was studied via the corrosive wear rate, the load bearing capacity of passive film and the relationship between pitting and corrosive wear. There is a critical load at natural potential, below which the corrosive wear rate is slightly lowered by Cl–, while above which is increased. At natural potential there are more pits at low load than that at a higher one in the wear tracks and the pits are also deeper. The load bearing capacity is lowered by Cl– at passive region and then the corrosive wear rate increased.

  11. Characteristics and Modification of Non-metallic Inclusions in Titanium-Stabilized AISI 409 Ferritic Stainless Steel

    Science.gov (United States)

    Kruger, Dirk; Garbers-Craig, Andrie

    2017-02-01

    This study describes an investigation into the improvement of castability, final surface quality and formability of titanium-stabilized AISI 409 ferritic stainless steel on an industrial scale. Non-metallic inclusions found in this industrially produced stainless steel were first characterized using SEM-EDS analyses through the INCA-Steel software platform. Inclusions were found to consist of a MgO·Al2O3 spinel core, which acted as heterogeneous nucleation site for titanium solubility products. Plant-scale experiments were conducted to either prevent the formation of spinel, or to modify it by calcium treatment. Modification to spherical dual-phase spinel-liquid matrix inclusions was achieved with calcium addition, which eliminated submerged entry nozzle clogging for this grade. Complete modification to homogeneous liquid calcium aluminates was achieved at high levels of dissolved aluminum. A mechanism was suggested to explain the extent of modification achieved.

  12. Effect of Welding Processes on Tensile and Impact Properties, Hardness and Microstructure of AISI 409M Ferritic Stainless Joints Fabricated by Duplex Stainless Steel Filler Metal

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; K Shanmugam; V Balasubramanian

    2009-01-01

    The effect of welding processes such as shielded metal arc welding, gas metal arc welding and gas tungsten arc welding on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade is studied. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the welded joints have been evaluated and the results are compared. From this investigatio.n, it is found that gas tungsten arc welded joints of ferritic stainless steel have superior tensile and impact properties compared with shielded metal are and gas metal arc welded joints and this is mainly due to the presence of finer grains in fusion zone and heat affected zone.

  13. Study of corrosion resistance of AISI 444 ferritic stainless steel for application as a biomaterial; Estudo da resistencia a corrosao do aco inoxidavel ferritico AISI 444 para aplicacao como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Rogerio Albuquerque

    2014-09-01

    Ferritic stainless steels are ferromagnetic materials. This property does not allow their use in orthopedic prosthesis. Nevertheless, in some specific applications, this characteristic is very useful, such as, for fixing dental and facial prostheses by using magnetic attachments. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and Ti and Nb stabilizers, were investigated for magnetic dental attachments application. The ISO 5832-1 (ASTM F-139) austenitic stainless steel and a commercial universal keeper for dental attachment (Neo-magnet System) were evaluated for comparison reasons. The first stainless steel is the most used metallic material for prostheses, and the second one, is a ferromagnetic keeper for dental prostheses (NeoM). In vitro cytotoxicity analysis was performed by the red neutral incorporation method. The results showed that the AISI 444 stainless steel is non cytotoxic. The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. The highest susceptibility to pitting corrosion was associated to the NeoM SS. This steel was also associated to the highest dopant concentration. The comparatively low levels of chromium (nearly 12.5%) and molybdenum (0.3%) of NeoM relatively to the other studied stainless steels are the probable cause of its lower corrosion resistance. The NeoM chemical composition does not match that of the SUS444 standards. The AISI 444 SS pitting resistance was equivalent to the ISO 5832-1 pointing out that it is a potential candidate for replacement of commercial ferromagnetic alloys used

  14. The effect of glutaraldehyde on the development of marine biofilms formed on surfaces of AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Tapper, R.C.; Smith, J.R.; Beech, I.B. [Univ. of Portsmouth (United Kingdom). School of Chemistry, Physics, and Radiography; Viera, M.R.; Guiamet, P.S.; Videla, H. [Univ. of La Plata (Argentina); Swords, C.L.; Edyvean, R.G.J. [Univ. of Sheffield (United Kingdom). Dept. of Mechanical and Process Engineering

    1997-08-01

    The effect of pre-conditioning polished and unpolished AISI 304 stainless steel surfaces with glutaraldehyde on the attachment, growth and morphology of an aerobic consortium of marine bacteria was investigated using total cell number counts, epifluorescence microscopy, Atomic Force Microscopy (AFM), Environmental Scanning Electron Microscopy (ESEM) and grazing-angle Fourier Transform Infrared (FTIR) spectroscopy. Both fully hydrated and dehydrated biofilms were studied using AFM and ESEM. Formation of the conditioning layer on steel surfaces from the culture medium, in the presence and absence of glutaraldehyde was monitored in-situ employing AFM and Grazing Angle FTIR spectroscopy. The influence of both surface area and surface energy upon the numbers of bacteria attached to polished and unpolished coupons was determined. This study has shown the influence of pretreatment of AISI 304 stainless steel with glutaraldehyde upon biofilm formation and has demonstrated the ability of AFM, ESEM and FTIR to be used as valuable tools for the in-situ investigation of the effect of biocides on bacterial biofilms.

  15. Corrosion Inhibition of AISI 316L and Modified-AISI 630 Stainless Steel by the New Organic Inhibitor [(CH32N]3PSe in Chloride Media:Electrochemical and Physical Study

    Directory of Open Access Journals (Sweden)

    Yafa ZARGOUNI

    2015-04-01

    Full Text Available We evaluate the effect of the Tris-dimethylaminoselenophosphoramide (SeAPon the corrosion inhibition of modified-AISI 630 and AISI 316L stainless steel (SS in 3 wt. % NaCl. The electrochemical behaviors of tested SS samples are investigated before and after adding the Seep into the chloride media by potentiodynamic polarization technique. The adsorption of SeAP onto both SS surfaces is verified by global discharge optical emission spectroscopy (GDOES.  SeAP is found to be a good inhibitor for SS corrosion, especially when added at a concentration of 0.5 wt. %.

  16. Study of carbonitriding thermochemical treatment by plasma screen in active with pressures main austenitic stainless steels AISI 409 and AISI 316L; Estudo do tratamento termoquimico de carbonitretacao por plasma em tela ativa com pressoes variaveis nos acos inoxidaveis austenitico AISI 316L e ferririco AISI 409

    Energy Technology Data Exchange (ETDEWEB)

    Melo, M.S.; Oliveira, A.M.; Leal, V.S.; Sousa, R.R.M. de; Alves Junior, C. [Centro Federal de Educacao Tecnologica do Maranhao (CEFET/MA), Sao Luis, MA (Brazil); Centro Federal de Educacao Tecnologica do Piaui (CEFET/PI), Teresina, PI (Brazil); Universidade Federal do Rio Grande do Norte (DF/UFRN), Natal, RN (Brazil). Dept. de Fisica. Labplasma

    2010-07-01

    The technique called Active Screen Plasma Nitriding (ASPN) is being used as an alternative once it offers several advantages with respect to conventional DC plasma. In this method, the plasma does not form directly in the sample's surface but on a screen, in such a way that undesired effects such as the edge effect is minimized. Stainless steels present not very satisfactory wearing characteristics. However, plasma carbonitriding has been used as to improve its resistance to wearing due to the formation of a fine surface layer with good properties. In this work, samples of stainless steel AISI 316L and AISI 409 were treated at pressures of 2.5 and 5 mbar. After the treatments they were characterized by microhardness, microscopy and Xray diffraction. Microscopy and hardness analysis showed satisfactory layers and toughness in those steels. (author)

  17. Microstructure, mechanical properties and chemical degradation of brazed AISI 316 stainless steel/alumina systems

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, O.C. [Instituto Superior de Engenharia do Porto (ISEP), Rua Dr. Antonio Bernardino de Almeida 431, 4200-072 Porto (Portugal)], E-mail: omp@isep.ipp.pt; Barbosa, M.A. [Instituto de Engenharia Biomedica (INEB), Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Roberto Frias s/n, 4200-465 Porto (Portugal)

    2008-05-15

    The main aims of the present study are simultaneously to relate the brazing parameters with: (i) the correspondent interfacial microstructure, (ii) the resultant mechanical properties and (iii) the electrochemical degradation behaviour of AISI 316 stainless steel/alumina brazed joints. Filler metals on such as Ag-26.5Cu-3Ti and Ag-34.5Cu-1.5Ti were used to produce the joints. Three different brazing temperatures (850, 900 and 950 deg. C), keeping a constant holding time of 20 min, were tested. The objective was to understand the influence of the brazing temperature on the final microstructure and properties of the joints. The mechanical properties of the metal/ceramic (M/C) joints were assessed from bond strength tests carried out using a shear solicitation loading scheme. The fracture surfaces were studied both morphologically and structurally using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The degradation behaviour of the M/C joints was assessed by means of electrochemical techniques. It was found that using a Ag-26.5Cu-3Ti brazing alloy and a brazing temperature of 850 deg. C, produces the best results in terms of bond strength, 234 {+-} 18 MPa. The mechanical properties obtained could be explained on the basis of the different compounds identified on the fracture surfaces by XRD. On the other hand, the use of the Ag-34.5Cu-1.5Ti brazing alloy and a brazing temperature of 850 deg. C produces the best results in terms of corrosion rates (lower corrosion current density), 0.76 {+-} 0.21 {mu}A cm{sup -2}. Nevertheless, the joints produced at 850 deg. C using a Ag-26.5Cu-3Ti brazing alloy present the best compromise between mechanical properties and degradation behaviour, 234 {+-} 18 MPa and 1.26 {+-} 0.58 {mu}A cm{sup -2}, respectively. The role of Ti diffusion is fundamental in terms of the final value achieved for the M/C bond strength. On the contrary, the Ag and Cu distribution along the

  18. Electrochemical characterization of AISI 316L stainless steel in contact with simulated body fluid under infection conditions.

    Science.gov (United States)

    López, Danián Alejandro; Durán, Alicia; Ceré, Silvia Marcela

    2008-05-01

    Titanium and cobalt alloys, as well as some stainless steels, are among the most frequently used materials in orthopaedic surgery. In industrialized countries, stainless steel devices are used only for temporary implants due to their lower corrosion resistance in physiologic media when compared to other alloys. However, due to economical reasons, the use of stainless steel alloys for permanent implants is very common in developing countries. The implantation of foreign bodies is sometimes necessary in the modern medical practice. However, the complex interactions between the host and the can implant weaken the local immune system, increasing the risk of infections. Therefore, it is necessary to further study these materials as well as the characteristics of the superficial film formed in physiologic media in infection conditions in order to control their potential toxicity due to the release of metallic ions in the human body. This work presents a study of the superficial composition and the corrosion resistance of AISI 316L stainless steel and the influence of its main alloying elements when they are exposed to an acidic solution that simulates the change of pH that occurs when an infection develops. Aerated simulated body fluid (SBF) was employed as working solution at 37 degrees C. The pH was adjusted to 7.25 and 4 in order to reproduce normal body and disease state respectively. Corrosion resistance was measured by means of electrochemical impedance spectroscopy (EIS) and anodic polarization curves.

  19. Wear properties of Fe-Cr-C and B{sub 4}C powder coating on AISI 316 stainless steel analyzed by the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Gur, Ali Kaya; Ozay, Cetin; Orhan, Ayhan; Buytoz, Soner; Caligulu, Ugur; Yigitturk, Necmettin [Firat Univ., Elazig (Turkey). Faculty of Technical Education

    2014-06-01

    In this study, the plasma arc welded cladding of FeCrC and B{sub 4}C powder mixtures alloyed with 70 wt.-% Cr on the surface of AISI 316 stainless steel was investigated. Application of the Taguchi method revealed respective effects on the abrasive wear resistance of the cladding layer on the stainless steel. The abrasive wear behaviour of the AISI 316 stainless steel surfaces coated with Fe-Cr-C and with 10 wt.-%, 15 wt.-%, 20 wt.-%, and 25 wt.-% B{sub 4}C was investigated by using four loads and four distances for the 220 mesh SiC abrasive. Results were analyzed by variance analysis using ANOVA, and effects of parameters on the wear rate were determined as percentage rate. Furthermore, the error ratio was statistically evaluated. The experimental results were analyzed by the respective analysis of means and variance which is discussed in detail. (orig.)

  20. Correlation between surface physicochemical properties and the release of iron from stainless steel AISI 304 in biological media.

    Science.gov (United States)

    Hedberg, Yolanda; Karlsson, Maria-Elisa; Blomberg, Eva; Odnevall Wallinder, Inger; Hedberg, Jonas

    2014-10-01

    Stainless steel is widely used in biological environments, for example as implant material or in food applications, where adsorption-controlled ligand-induced metal release is of importance from a corrosion, health, and food safety perspective. The objective of this study was to elucidate potential correlations between surface energy and wettability of stainless steel surfaces and the release of iron in complexing biological media. This was accomplished by studying changes in surface energies calculated from contact angle measurements, surface oxide composition (X-ray photoelectron spectroscopy), and released iron (graphite furnace atomic absorption spectroscopy) for stainless steel grade AISI 304 immersed in fluids containing bovine serum albumin or citric acid, and non-complexing fluids such as NaCl, NaOH, and HNO3. It was shown that the surface wettability and polar surface energy components were all influenced by adventitious atmospheric carbon (surface contamination of low molecular weight), rather than differences in surface oxide composition in non-complexing solutions. Adsorption of both BSA and citrate, which resulted in ligand-induced metal release, strongly influenced the wettability and the surface energy, and correlated well with the measured released amount of iron.

  1. Study of the tensile behavior of AISI type 316 stainless steel using acoustic emission and infrared thermography techniques

    Directory of Open Access Journals (Sweden)

    Thodamrakandy Haneef

    2015-07-01

    Full Text Available Acoustic emission (AE and infrared thermography technique (IRT have been used to study the tensile behavior of AISI type 316 stainless steel. Strain rates of tensile testing were varied from 1.4 × 10−3 s−1 to 1.4 × 10−2 s−1. AE root mean square voltage increases with increase in strain rate due to the increase in source activation. Dominant frequency of the AE signals generated during different regions of tensile deformation has also been used to compare the results for different strain rates. The dominant frequency increases from elastic region to around 590 kHz during work hardening and 710 kHz around ultimate tensile strength (UTS for all the strain rates. Temperature changes during different regions of deformation are monitored using infrared thermography. The temperature rise in the work hardening region is found to approximately increase linearly with time and from the slopes of the linear regression analyses the rate of temperature rise in the work-hardening region is obtained which is found to be very sensitive to strain rates. From the experimental results an empirical equation that relates the rate of temperature increase with strain rate and thermal hardening coefficient is obtained. The correlation between the variation of AE dominant frequency and temperature rise during different deformation regions provided better insight into the tensile behavior of AISI type 316 SS for different strain rates.

  2. Phase transformations in an AISI 410S stainless steel observed in directional and laser-induced cooling regimes

    Directory of Open Access Journals (Sweden)

    Milton Sergio Fernandes de Lima

    2012-02-01

    Full Text Available The applications of the chromium ferritic stainless steel AISI 410S have been considerably increased in the last years in many technical fields as chemical industries and oil or gas transportation. However, the phase transformation temperatures are, currently, unknown for this alloy. The aim of this work is to determine the alpha to gamma transformation temperatures of the AISI 410S alloy in different cooling conditions and to analyze them using continuous cooling theory. In order to achieve different cooling rates and thermal conditions, two complementary techniques were used: Bridgman furnace crystal growth and laser remelting technique. The measured solidification temperature was around 1730 and 1750 K. Plate-like and dendritic austenite precipitates were obtained in solid-state phase using growth rates between 5 and 10 µm/s in directional growth experiments. Only plate-like austenite phase was observed in the experiments using growth rates above 100 µm/s. The appearance of dendrites, with the consequent segregation of the elements, can be previously determined by the microstructure modeling currently proposed. Massive austenite can be produced from 0.3 to 10 mm/s rates at temperatures between 1100-1300 K. The structure might be less sensitive to corrosion because this phase is produced without microsegregation.

  3. Optimisation of GTAW parameters for the tensile strength of AISI 304 stainless steel welds using the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Ertan, Rukiye

    2012-07-01

    The influence of welding parameters, i. e. the welding current, root gap and the shielding gas flow rate, on the tensile strength of AISI 304 austenitic stainless steel welded with gas tungsten arc welding was investigated. To determine the optimum levels of the parameters, the Taguchi approach was used to increase the tensile strength. The results were analysed by investigating the variance by which welding parameters significantly affect the response. Mathematical models were developed to describe the influence of the selected parameters on the tensile strength. The results were confirmed by experiments. [German] Der Einfluss der Schweissparameter, d. h. der Schweissstromstaerke, des Wurzelspaltes und des Schutzgasdurchflusses, auf die Zugfestigkeit des WIG-geschweissten hochlegierten Stahles AISI 304 ist in der diesem Beitrag zugrunde liegenden Studie untersucht worden. Um die optimale Groesse der Parameter in Bezug auf eine Erhoehung der Zugfestigkeit zu bestimmen, wurde der Ansatz nach Taguchi gewaehlt. Die Ergebnisse wurden analysiert, indem die Varianz ermittelt wurde, mit der die Schweissparameter signifikant die Ergebnisse veraendern. Es wurden mathematische Modelle entwickelt, um den Einfluss der gewaehlten Parameter auf die Zugfestigkeit zu beschreiben. Die Ergebnisse wurden durch Experimente bestaetigt.

  4. Comparison of Roller Burnishing Method with Other Hole Surface Finishing Processes Applied on AISI 304 Austenitic Stainless Steel

    Science.gov (United States)

    Akkurt, Adnan

    2011-08-01

    Component surface quality and selection of the optimum material are the main factors determining the performance of components used in machine manufacturing. The level of hole surface quality can be evaluated by the measurements regarding surface roughness, micro-hardness, and cylindricity. In this study, data had been obtained for different hole drilling methods. The characteristics of materials obtained after applications were compared for different hole-finishing processes to identify best hole drilling method. AISI 304 austenitic stainless steel material was used. Surface finishing of holes were performed using drilling, turning, reaming, grinding, honing, and roller burnishing methods. The results of the study show that the roller burnishing method gives the best results for mechanical, metallurgical properties, and hole surface quality of the material. On the other hand, the worst characteristics were obtained in the drilling method.

  5. Experimental Determination of Temperature During Rotary Friction Welding of AA1050 Aluminum with AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Eder Paduan Alves

    2012-03-01

    Full Text Available The purpose of this study was the temperature monitoring at bonding interface during the rotary friction welding process of dissimilar materials: AA1050 aluminum with AISI 304 stainless steel. As it is directly related to the mechanical strenght of the junction, its experimental determination in real time is of fundamental importance for understanding and characterizing the main process steps, and the definition and optimization of parameters. The temperature gradients were obtained using a system called Thermocouple Data-Logger, which allowed monitoring and recording data in real-time operation. In the graph temperature versus time obtained, the heating rates, cooling were analyzed, and the maximum temperature was determined that occurred during welding, and characterized every phases of the process. The efficiency of this system demonstrated by experimental tests and the knowledge of the temperature at the bonding interface open new lines of research to understand the process of friction welding.

  6. Effect of copper on the formation of strain-induced martensite in two austenitic stainless steels AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    Gilapa, Leonidas Cayo Mamani, E-mail: leonidas@ifsc.edu.br [Instituto Federal de Santa Catarina, Rua Pavão, 1337, Bairro Costa e Silva, Joinville, SC CEP 89220-200 (Brazil); Oliveira, Carlos Augusto Silva de, E-mail: carlos.a@ufsc.br [Universidade Federal de Santa Catarina, Campus Universitário Reitor João David Ferreira Lima, Trindade, Florianópolis, SC CEP 88040-970 (Brazil); Silva, Manoel Ribeiro da, E-mail: mrsilva@unifei.edu.br [Universidade Federal de Itajubá, Instituto de Ciências, Itajubá (Brazil)

    2015-01-12

    The transformation of strain-induced martensite in two metastable austenitic stainless steels, AISI 304, with the same basic composition and concentrations of Cu variables was characterized by transmission electron microscopy and magnetic measurements. The deformations to induce the formation of martensite were performed using the test of conformability with Nakajima tooling at room temperature. The results obtained for the various samples showed that the steel with lower content of Cu presented higher degree of magnetization. Also it was observed that the martensite magnetic α′ and paramagnetic ε are formed at the intersection of dislocation, in the grain boundary, inside and at the edge of twinned and the stacking faults in the austenite.

  7. Application of Deep Cryogenic Treatment to Uncoated Tungsten Carbide Inserts in the Turning of AISI 304 Stainless Steel

    Science.gov (United States)

    Özbek, Nursel Altan; Çİçek, Adem; Gülesİn, Mahmut; Özbek, Onur

    2016-12-01

    This study investigated the effects of deep cryogenic treatment (DCT) on the wear performance of uncoated tungsten carbide inserts. AISI 304 austenitic stainless steel, widely used in industry, was selected as the workpiece material. Cutting experiments showed that the amount of wear significantly increased with increasing cutting speed. In addition, it was found that DCT contributed to the wear resistance of the turning inserts. The treated turning inserts were less worn by 48 and 38 pct in terms of crater wear and notch wear, respectively, whereas they exhibited up to 18 pct superior wear performance in terms of flank wear. This was attributed to the precipitation of new and finer η-carbides and their homogeneous distribution in the microstructure of the tungsten carbide material after deep cryogenic treatment. Analyses via image processing, hardness measurements, and SEM observations confirmed these findings.

  8. Application of Deep Cryogenic Treatment to Uncoated Tungsten Carbide Inserts in the Turning of AISI 304 Stainless Steel

    Science.gov (United States)

    Özbek, Nursel Altan; Çİçek, Adem; Gülesİn, Mahmut; Özbek, Onur

    2016-09-01

    This study investigated the effects of deep cryogenic treatment (DCT) on the wear performance of uncoated tungsten carbide inserts. AISI 304 austenitic stainless steel, widely used in industry, was selected as the workpiece material. Cutting experiments showed that the amount of wear significantly increased with increasing cutting speed. In addition, it was found that DCT contributed to the wear resistance of the turning inserts. The treated turning inserts were less worn by 48 and 38 pct in terms of crater wear and notch wear, respectively, whereas they exhibited up to 18 pct superior wear performance in terms of flank wear. This was attributed to the precipitation of new and finer η-carbides and their homogeneous distribution in the microstructure of the tungsten carbide material after deep cryogenic treatment. Analyses via image processing, hardness measurements, and SEM observations confirmed these findings.

  9. Corrosion resistance of multilayer hybrid sol-gel coatings deposited on the AISI 316L austenitic stainless steel

    Science.gov (United States)

    Caballero, Y. T.; Rondón, E. A.; Rueda, L.; Hernández Barrios, C. A.; Coy, A.; Viejo, F.

    2016-02-01

    In the present work multilayer hybrid sol-gel coatings were synthesized on the AISI 316L austenitic stainless steel employed in the fabrication of orthopaedic implants. Hybrid sols were obtained from a mixture of inorganic precursor, TEOS, and organic, GPTMS, using ethanol as solvent, and acetic acid as catalyst. The characterization of the sols was performed using pH measurements, rheological tests and infrared spectroscopy (FTIR) for different ageing times. On the other hand, the coatings were characterized by scanning electron microscopy (SEM), while the corrosion resistance was evaluated using anodic potentiodynamic polarization in SBF solution at 37±2°C. The results confirmed that sol-gel synthesis employing TEOS-GPTMS systems produces uniform and homogeneous coatings, which enhanced the corrosion resistance with regard to the parent alloy. Moreover, corrosion performance was retained after applying more than one layer (multilayer coatings).

  10. TEM and AES investigations of the natural surface nano-oxide layer of an AISI 316L stainless steel microfibre.

    Science.gov (United States)

    Ramachandran, Dhanya; Egoavil, Ricardo; Crabbe, Amandine; Hauffman, Tom; Abakumov, Artem; Verbeeck, Johan; Vandendael, Isabelle; Terryn, Herman; Schryvers, Dominique

    2016-11-01

    The chemical composition, nanostructure and electronic structure of nanosized oxide scales naturally formed on the surface of AISI 316L stainless steel microfibres used for strengthening of composite materials have been characterised using a combination of scanning and transmission electron microscopy with energy-dispersive X-ray, electron energy loss and Auger spectroscopy. The analysis reveals the presence of three sublayers within the total surface oxide scale of 5.0-6.7 nm thick: an outer oxide layer rich in a mixture of FeO.Fe2 O3 , an intermediate layer rich in Cr2 O3 with a mixture of FeO.Fe2 O3 and an inner oxide layer rich in nickel.

  11. Tribological behavior of AISI302 austenitic stainless steel modified by elevated temperature nitrogen plasma immersion ion implantation

    Institute of Scientific and Technical Information of China (English)

    JIANG Shao-qun; MA Xin-xin; SUN Yue

    2004-01-01

    AISI302 stainless steel samples were modified by elevated temperature nitrogen plasma immersion ion implantation at temperature ranging from 330 ℃ to 450 ℃. The tribological behaviors of the implanted layers of the samples were investigated. The samples were characterized by Auger electron spectroscopy (AES), glancing angle X-ray diffraction (GXRD), and nanoindentation. The results show that the implantation temperature plays an important rule on the microstructure and surface properties of the implanted layers. The thickness of the modified layer implanted at 390 ℃ is about 9 μm. It is improved about two orders compared with that of the implanted at room temperature. The surface nanohardness and the wear resistance of elevated temperature implanted layers increase significantly, and the friction coefficient decreases obviously in comparison with the unimplanted one. These data suggests that the improvement results from the formation of new phases such as ε-(Fe, Cr, Ni)2+xN, or noncrystal phase.

  12. Corrosion behavior of powder metallurgical stainless steels in urban and marine environments

    Directory of Open Access Journals (Sweden)

    Bautista, A.

    2006-06-01

    Full Text Available This work studies the development of corrosive attack on sintered components manufactured from AISI 316L and AISI 304L powders. The stainless steels were sintered in vacuum and in nitrogen-base atmosphere at 1,120 and 1,250 ºC, and their corrosion resistance was then analyzed by electrochemical techniques and by atmospheric corrosion testing (two years at urban and marine test sites. Images are shown of the morphology of the attack on the surface of the stainless steels and the development of this attack in the interior of the material.

    Este trabajo estudia el desarrollo del proceso corrosivo en componentes sinterizados fabricados a partir de polvos de AISI 316L y AISI 304L. Los aceros inoxidables fueron sinterizados en vacío y en atmósfera base nitrógeno a 1.120 y 1.250 ºC y, su resistencia a corrosión se ha analizado mediante técnicas electroquímicas y mediante ensayos de corrosión atmosférica (dos años en ambientes urbano y marino. Se muestran imágenes de la morfología del ataque en la superficie de los aceros inoxidables y del desarrollo de este ataque en el interior del material.

  13. Exploration of surface hydrophilic properties on AISI 304 stainless steel and silicon wafer against aging after atmospheric pressure plasma treatment

    Science.gov (United States)

    Chuang, Shang-I.; Duh, Jenq-Gong

    2014-11-01

    The aim of this work is to seek the enhanced surface hydrophilic properties on AISI 304 stainless steel and silicon wafer after atmospheric pressure plasma treatment using a specifically designed atmospheric pressure plasma jet. The aging tendency of surface hydrophilic property under air is highlighted. It is concluded that both of the silicon wafer and stainless steel treated with plasma generated from supply gas of argon 15 slm mixed with oxygen 40 sccm shows a better tendency on remaining high water contact angle as compared to that with pure argon and nitrogen addition. Additional peaks of O I (777, 844 nm), O II (408 nm) are detected by optical emission spectroscope indicating the presence of the oxygen radicals and ionic species, which interact with surfaces and thus contribute to low water contact angle (WCA) surfaces. Moreover, the result acquired from X-ray photoelectron spectroscopy (XPS) indicates that the increase in the oxygen-related bonding exhibits a better contribution on remaining high surface energy over a period of time.

  14. Parametric Optimization Of Gas Metal Arc Welding Process By Using Grey Based Taguchi Method On Aisi 409 Ferritic Stainless Steel

    Science.gov (United States)

    Ghosh, Nabendu; Kumar, Pradip; Nandi, Goutam

    2016-10-01

    Welding input process parameters play a very significant role in determining the quality of the welded joint. Only by properly controlling every element of the process can product quality be controlled. For better quality of MIG welding of Ferritic stainless steel AISI 409, precise control of process parameters, parametric optimization of the process parameters, prediction and control of the desired responses (quality indices) etc., continued and elaborate experiments, analysis and modeling are needed. A data of knowledge - base may thus be generated which may be utilized by the practicing engineers and technicians to produce good quality weld more precisely, reliably and predictively. In the present work, X-ray radiographic test has been conducted in order to detect surface and sub-surface defects of weld specimens made of Ferritic stainless steel. The quality of the weld has been evaluated in terms of yield strength, ultimate tensile strength and percentage of elongation of the welded specimens. The observed data have been interpreted, discussed and analyzed by considering ultimate tensile strength ,yield strength and percentage elongation combined with use of Grey-Taguchi methodology.

  15. Effect of electromagnetic interaction during fusion welding of AISI 2205 duplex stainless steel on the corrosion resistance

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; González-Sánchez, J.; García-Hernández, R.; Dzib-Pérez, L.; Curiel-López, F. F.

    2017-02-01

    The effect of electromagnetic interaction of low intensity (EMILI) applied during fusion welding of AISI 2205 duplex stainless steel on the resistance to localised corrosion in natural seawater was investigated. The heat affected zone (HAZ) of samples welded under EMILI showed a higher temperature for pitting initiation and lower dissolution under anodic polarisation in chloride containing solutions than samples welded without EMILI. The EMILI assisted welding process developed in the present work enhanced the resistance to localised corrosion due to a modification on the microstructural evolution in the HAZ and the fusion zone during the thermal cycle involved in fusion welding. The application of EMILI reduced the size of the HAZ, limited coarsening of the ferrite grains and promoted regeneration of austenite in this zone, inducing a homogeneous passive condition of the surface. EMILI can be applied during fusion welding of structural or functional components of diverse size manufactured with duplex stainless steel designed to withstand aggressive environments such as natural seawater or marine atmospheres.

  16. Surface interactions of a W-DLC-coated biomedical AISI 316L stainless steel in physiological solution.

    Science.gov (United States)

    Antunes, Renato A; de Lima, Nelson Batista; Rizzutto, Márcia de Almeida; Higa, Olga Zazuco; Saiki, Mitiko; Costa, Isolda

    2013-04-01

    The corrosion stability of a W-DLC coated surgical AISI 316L stainless steel in Hanks' solution has been evaluated. Particle induced X-ray emission (PIXE) measurements were performed to evaluate the incorporation of potentially bioactive elements from the physiological solution. The film structure was analyzed by X-ray diffractometry and micro-Raman spectroscopy. The wear behavior was assessed using the sphere-on-disc geometry. The in vitro biocompatibility of the W-DLC film was evaluated by cytotoxicity tests. The corrosion resistance of the stainless steel substrate decreased in the presence of the PVD layer. EIS measurements suggest that this behavior was closely related to the corrosion attack through the coating pores. PIXE measurements revealed the presence of Ca and P in the W-DLC film after immersion in Hanks' solution. This result shows that the PIXE technique can be applied to identify and evaluate the incorporation of bioactive elements by W-DLC films. The film showed good wear resistance and biocompatibility.

  17. Biocompatibility studies of low temperature nitrided and collagen-I coated AISI 316L austenitic stainless steel.

    Science.gov (United States)

    Martinesi, M; Stio, M; Treves, C; Borgioli, F

    2013-06-01

    The biocompatibility of austenitic stainless steels can be improved by means of surface engineering techniques. In the present research it was investigated if low temperature nitrided AISI 316L austenitic stainless steel may be a suitable substrate for bioactive protein coating consisting of collagen-I. The biocompatibility of surface modified alloy was studied using as experimental model endothelial cells (human umbilical vein endothelial cells) in culture. Low temperature nitriding produces modified surface layers consisting mainly of S phase, the supersaturated interstitial solid solution of nitrogen in the austenite lattice, which allows to enhance surface microhardness and corrosion resistance in PBS solution. The nitriding treatment seems to promote the coating with collagen-I, without chemical coupling agents, in respect of the untreated alloy. For biocompatibility studies, proliferation, lactate dehydrogenase levels and secretion of two metalloproteinases (MMP-2 and MMP-9) were determined. Experimental results suggest that the collagen protection may be favourable for endothelial cell proliferation and for the control of MMP-2 release.

  18. Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Mamede, Anne-Sophie, E-mail: anne-sophie.mamede@ensc-lille.fr [University Lille, CNRS, ENSCL, Centrale Lille, University Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Nuns, Nicolas, E-mail: nicolas.nuns@univ-lille1.fr [University Lille, CNRS, ENSCL, Centrale Lille, University Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Cristol, Anne-Lise, E-mail: anne-lise.cristol@ec-lille.fr [University Lille, CNRS, Centrale Lille, Arts et Métiers Paris Tech, FRE 3723 – LML – Laboratoire de Mécanique de Lille, F-59000 Lille (France); Cantrel, Laurent, E-mail: laurent.cantrel@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, PSN-RES, Cadarache, Saint Paul lez Durance, 13115 (France); Laboratoire de Recherche Commun IRSN-CNRS-Lille 1: «Cinétique Chimique, Combustion, Réactivité» (C3R), Cadarache, Saint Paul lez Durance, 13115 (France); Souvi, Sidi, E-mail: sidi.souvi@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire, PSN-RES, Cadarache, Saint Paul lez Durance, 13115 (France); Laboratoire de Recherche Commun IRSN-CNRS-Lille 1: «Cinétique Chimique, Combustion, Réactivité» (C3R), Cadarache, Saint Paul lez Durance, 13115 (France); and others

    2016-04-30

    Graphical abstract: - Highlights: • Mutitechnique characterisation of oxidised 304L. • Oxidation at high temperature under steam and air conditions of 304L stainless steel. • Chromium and manganese oxides formed in the outer layer. • Oxide profiles differ in air or steam atmosphere. - Abstract: In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8–12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe{sub 2}O{sub 3} oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

  19. Characterization Of Oxide Layers Produced On The AISI 321 Stainless Steel After Annealing

    Directory of Open Access Journals (Sweden)

    Bochnowski W.

    2015-09-01

    Full Text Available In this study, the structure, chemical composition and topography of oxide layers produced on the surface of the AISI 321 austenitic steel in the annealing process were analyzed. Heat treatment was done at 980°C temperature for 1 hour time in different conditions. The annealing was done in a ceramic furnace in oxidation atmosphere and in vacuum furnaces with cylindrical molybdenum and graphite chambers. The analysis was carried out using the following methods: a scanning electron microscope (SEM equipped with an energy-dispersive X-ray spectrometer (EDX, a transmission electron microscope (TEM equipped with an energy-dispersive X-ray spectrometer (EDX, an X-ray diffractometer (XRD, a secondary ion mass spectrometer with time-of-flight mass analyzer (TOF SIMS and an atomic force microscope (AFM. The oxide layer formed during annealing of the AISI 321 steel at 980°C consisted of sub-layers, diversified in the chemical composition. The thickness of the oxidized layer is depended on the annealing conditions. In a ceramic furnace in oxidation atmosphere, the thickness of the oxide layer was of 300-500 nm, in a vacuum furnace with molybdenum and graphite heating chambers, it ranged from 40 to 300 nm and from a few to 50 nm, respectively. TOF SIMS method allows to get average (for the surface of 100 μm × 100 μm depth profiles of concentration of particular elements and elements combined with oxygen. In oxide layers formed in vacuum furnaces there are no iron oxides. Titanium, apart from being bounded with carbon in carbides, is a component of the oxide layer formed on the surface of the AISI 321 steel.

  20. Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lin Yimin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: linyimin_2001@yahoo.com.cn; Lu Jian [LASMIS, University of Technology of Troyes, 10000 Troyes (France); Wang Liping [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Tao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Xue Qunji [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China)]. E-mail: qjxue@ns.lzb.ac.cn

    2006-12-15

    A plastic deformation surface layer with nanocrystalline grains was produced on AISI 321 austenitic stainless steel by means of surface mechanical attrition treatment (SMAT). Low-temperature nitriding of SMAT and un-SMAT AISI 321 stainless steel was carried out in pulsed-DC glow discharge. The effect of SMAT pretreatment on the microstructure and properties of the stainless steel were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Vickers hardness tester and UMT-2MT tribometer. The results show that the plasma nitriding of AISI 321 steel can be enhanced considerably by means of SMAT process before nitriding, and a much thicker nitrogen diffusion layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples. In addition, the wear resistance and load capacity of the nitrided layers on the SMAT samples was much higher than that of the un-SMAT samples due to the thicker S phase case and the gradient nitrogen diffusion layer.

  1. Comportamiento del desgaste del flanco en el torneado en seco de alta velocidad del acero AISI 316L//Flank wear behavior in the dry high‐speed turning of AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Yoandrys Morales-Tamayo

    2013-09-01

    Full Text Available El presente estudio experimental se centra en investigar los efectos de los parámetros corte en el desgaste de flanco con dos insertos recubiertos durante el torneado de acabado en seco a altas velocidades del acero inoxidable AISI 316L. Los efectos de los parámetros de corte fueron determinados utilizando un análisis de varianza y de regresión simple. Como principal resultado se obtuvo el efectosignificativo del avance y del tiempo de maquinado en el desgaste del flanco. El inserto de tres capas no sobrepasó el criterio de fin de vida del desgaste, mientras que el inserto de una capa sufrió un desgaste catastrófico para la mayor velocidad de corte. El desgaste del flanco tuvo mejor comportamiento para el avance de 0,08 mm/rev en todas las velocidades empleadas en este estudio.Palabras claves: torneado de alta velocidad, desgaste de flanco, acero inoxidable AISI 316L, estudio experimental, análisis de varianza y regresión.______________________________________________________________________________AbstractThe current experimental study is focused on investigating the effects of cutting parameters on flank wear in two coated carbide inserts during dry high speed finish turning of AISI 316L stainless steel. The effects of cutting parameters were determinate using analysis of variance and simple regression. As a main resulta significant effect of cutting feed and the machining time on flank wear was found. The three coating layers insert did not exceed the criterion of end of life of wear while the insert with one layer suffered a catastrophic wear at the highest cutting speed. The flank wear showed the best performance for the cuttingfeed of 0,08 mm/rev at all the speeds used in the study.Key words: high speed turning; flank wear; AISI 316L stainless steel, experimental study; analysis of variance and regression.

  2. Improvement in cavitation erosion resistance of AISI 316L stainless steel by friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Hajian, M. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Abdollah-zadeh, A., E-mail: zadeh@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Rezaei-Nejad, S.S.; Assadi, H. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Hadavi, S.M.M. [Department of Materials Science and Engineering, MA University of Technology, Tehran (Iran, Islamic Republic of); Chung, K. [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Engineering Research Institute, Seoul National University, Seoul (Korea, Republic of); Shokouhimehr, M. [Department of Chemical Engineering, College of Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-07-01

    Commercial AISI 316L plates with the initial grain size of 14.8 μm were friction stir processed (FSP) with different processing parameters, resulting in two fine-grained microstructures with the grain sizes of 4.6 and 1.7 μm. The cavitation erosion behavior, before and after FSP, was evaluated in terms of incubation time, cumulative mass loss and mean depth of erosion. A separate cavitation erosion test was performed on the transverse cross section of a FSP sample to reveal the effect of grain structure. It was observed that FSP samples, depending on their grain size, are at least 3–6 times more resistant than the base material against cavitation erosion. The improvement in cavitation erosion resistance is attributed to smaller grain structure, lower fraction of twin boundaries, and favorable crystallographic orientation of grains in FSP samples. The finer the grain size, the more cavitation erosion resistance was achieved. Moreover, the microstructures of eroded surfaces were studied using a scanning electron microscope equipped with EBSD, and an atomic force microscope. The mechanisms controlling the cavitation erosion damage in friction stir processed AISI 316L are also discussed.

  3. Fatigue Damage Monitoring in 304L Steel Specimens by an Acoustic Emission Method

    Directory of Open Access Journals (Sweden)

    Ould-Amer Ammar

    2014-06-01

    Full Text Available The aim of this work was to clarify fatigue crack initiation and propagation mechanisms in 304L austenitic stainless steel under different total-strain-amplitudes. A complete process from crack initiation and propagation was recorded by using the acoustic emission method in one hand, and replica method in another hand. The effect of strain amplitude on fatigue crack growth was investigated and a new representation of various fatigue curves associated to various levels of fatigue damage is proposed.

  4. Effect of the powder particle size on the wear behavior of boronized AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Guenen, Ali [Mustafa Kemal Univ., Hatay (Turkey). Dept. of Metallurgy and Material Engineering; Kuecuek, Yilmaz; Oege, Mecit; Goek, M. Sabri [Bartin Univ. (Turkey). Dept. of Mechanical Engineering; Er, Yusuf [Firat Univ., Elazig (Turkey); Cay, V. Veli [Dicle Univ., Diyarbakir (Turkey). Civil Aviation Higher School

    2015-06-01

    In this study, the AISI 304 steel specimens were boronized with nanoboron of the size of 10 50 nm and commercial Ekabor 3 powders (<1400 μm) at 950 C to 1000 C for 2 h and 4 h. Boronized steel specimens were characterized via SEM, microhardness and XRD analyses. Abrasive wear behavior of the specimens, boronized at different temperatures and treatment durations, were examined. The fixed ball micro-abrasion tests were carried out using the abrasive slurry, prepared with different SiC powder particle sizes on the boronized specimens at different rotational speeds. The specimens boronized with nanoboron powders exhibited a higher hardness and abrasive wear resistance than the samples boronized with the Ekabor 3 powders.

  5. Evaluation of the corrosion resistance of AISI 316 stainless steel filters

    Directory of Open Access Journals (Sweden)

    Luzinete Pereira Barbosa

    2005-06-01

    Full Text Available In this investigation, the corrosion resistance of AISI 316 SS filters prepared with powders in the size ranges 74-44 µm and 210-105 µm and compacted with pressures of 300 MPa and 400 MPa has been evaluated in naturally aerated 0.5 M H2SO4 solution at 25 °C. Weight loss of filters manufactured with compacting pressure of 400 MPa were significantly higher than that of filters compacted at 300 MPa. The filter compacted at 400 MPa had higher carbon and nitrogen contents compared to those compacted at 300 MPa. The former also had chromium rich precipitates and oxides in the grain boundaries. The pores in filters compacted at 400 MPa were smaller than in filters compacted at 300 MPa. Smaller pores favor the formation of concentration cells and consequently, increased crevice corrosion.

  6. Finite Element Analysis of Cross Rolling on AISI 304 Stainless Steel: Prediction of Stress and Strain Fields

    Science.gov (United States)

    Rout, Matruprasad; Pal, Surjya Kanta; Singh, Shiv Brat

    2017-02-01

    Studies on the effect of strain path during rolling has been carried out for a long time, but the same has not been done using Finite Element Analysis (FEA). Change in strain path affects the state variables in the rolled plate like stress, strain, temperature etc. In the current work, Finite Element Analysis for cross rolling of AISI 304 austenitic stainless steel has been carried out by rotating the plate by 90° in between the passes. To analyze stress and strain fields in the material for cross rolling, a full 3D model of work-roll and plate has been developed using rigid-viscoplastic finite element method. The stress and strain fields, considering von-Mises yield criteria, are calculated by using updated Lagrangian method. In addition to these, the model also calculates the normal pressure and strain rate distribution in the plate during cross rolling. The nature of the variations of stress and strain fields in the plate, predicted by the model, is in good agreement with the previously published works for unidirectional rolling.

  7. Influence of C, N and Ti concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M.C.; Carboneras, M.; Coy, A.E.; Viejo, F.; Arrabal, R.; Munoz, J.A. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040, Madrid (Spain)

    2004-07-01

    The influence of Ti, C, and N concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel has been studied. A kinetic study of the corrosion process has been carried out using gravimetric tests according to ASTM A-262 practices B and C (Streicher and Huey, respectively). The TTS diagrams were drawn as a function of alloying elements concentration (C, N and Ti). Materials characterization under several test conditions was carried out using Scanning Electron Microscopy (SEM) analysing microstructural characteristics and the attack microstructure. The chemical resistance of these steels to intergranular test was function of N, C and Ti concentration. High Ti and N concentration favoured the precipitation of TiN during the material manufacture process. N forms TiN very stable, causing the removal of Ti from the matrix and, indirectly, favouring the Cr{sub 23}C{sub 6} precipitation during the sensitization process and increasing the corrosion rate. In order to inhibit the intergranular corrosion in these materials the N and Ti concentrations must be optimised. (authors)

  8. Tribocorrosion Failure Mechanism of TiN/SiOx Duplex Coating Deposited on AISI304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Qiang Chen

    2016-11-01

    Full Text Available TiN/SiOx duplex coatings were synthesized on AISI304 stainless steel by plasma immersion ion implantation and deposition (PIIID followed by radio frequency magnetron sputtering (RFMS. The microstructure and tribocorrosion failure behaviors of the duplex coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, reciprocating-sliding tribometer, and electrochemical tests. The as-deposited duplex coating had a two-layered columnar growth structure consisting of face-centered cubic TiN and amorphous SiOx. Sliding tests showed that the TiN interlayer had good adhesion with the substrate, but the SiOx layer suffered from severe delamination failure. Friction force induced a number of micro-cracks in the coating, which provided channels for the diffusion of NaCl solution. The tribocorrosion test showed that the duplex coating exhibited a lower wear-performance in NaCl solution than in ambient atmosphere. Multi-scale chloride ion corrosion occurred simultaneously and substantially degraded the bonding strength of the columnar crystals or neighboring layers. Force-corrosion synergy damage eventually led to multi-degradation failure of the duplex coating. The presented results provide a comprehensive understanding of the tribocorrosion failure mechanism in coatings with duplex architecture.

  9. Comparison of the Electrochemical Behavior of Ti and Nanostructured Ti-Coated AISI 304 Stainless Steel in Strongly Acidic Solutions

    Science.gov (United States)

    Attarzadeh, Farid Reza; Elmkhah, Hassan; Fattah-Alhosseini, Arash

    2017-02-01

    In this study, the electrochemical behaviors of pure titanium (Ti) and nanostructured (NS) Ti-coated AISI 304 stainless steel (SS) in strongly acidic solutions of H2SO4 were investigated and compared. A type of physical vapor deposition method, cathodic arc evaporation, was applied to deposit NS Ti on 304 SS. Scanning electron microscope and X-ray diffraction were used to characterize surface coating morphology. Potentiodynamic polarization, electrochemical impedance spectroscopy, and Mott-Schottky (M-S) analysis were used to evaluate the passive behavior of the samples. Electrochemical measurements revealed that the passive behavior of NS Ti coating was better than that of pure Ti in 0.1 and 0.01 M H2SO4 solutions. M-S analysis indicated that the passive films behaved as n-type semiconductors in H2SO4 solutions and the deposition method did not affect the semiconducting type of passive films formed on the coated samples. In addition, this analysis showed that the NS Ti coating had lower donor densities. Finally, all electrochemical tests showed that the passive behavior of the Ti-coated samples was superior, mainly due to the formation of thicker, yet less defective passive films.

  10. Electrochemical study of AISI 304 stainless steel during the exposure at the disinfectant solutions with fungal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Stoica, M.; Bruma, M. [Department of Biochemistry and Technologies, Faculty of Food Science and Engineering, ' ' Dunarea de Jos' ' University of Galati, 111 Domneasca Street, 800201 Galati (Romania); Carac, G. [Department of Chemistry, Faculty of Sciences, ' ' Dunarea de Jos' ' University of Galati, 47 Domneasca Street, 800008 Galati (Romania)

    2010-12-15

    The effect of fungal suspensions on the disinfectant solution (Actisept with sodium dichloroisocyanurate as active substance, which releases 140 ppm active chlorine) and the corrosion behavior of type AISI 304 stainless steel (SS) were evaluated through linear polarization. The work presents a study of biocide Actisept solution as reference solution and the mixed solutions: reference biocide Actisept solution with three fungal suspensions (10 vol%), Aspergillus niger, Candida mycoderma, and Saccharomyces cerevisiae. The fungal suspension has an important influence on the synergistic effect of the SS corrosion in the following order: Saccharomyces cerevisiae > Candida mycoderma > Aspergillus niger. The E{sub corr} values from the mixed solutions decreased with immersion time of the samples. In the case of Aspergillus niger, the corrosion rate was lower than that of any other type of fungal suspension tested, because the arrangement in solutions, the size and composition of Aspergillus niger spores were more favorable to protect the spores of the chemical and the electrical stressing. The results showed that there is a synergistic effect between the active substances from the disinfectant, fungal suspensions and applied potential, thus this effect can be taken into consideration for the hygienic and safety food industry. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Prediction for pitting corrosion of AISI type 403 stainless steel in chloride-containing borate buffer solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yancheng [Pennsylvania State Univ. (United States); Macdonald, D.D. [Pennsylvania State Univ. (United States). Center for Electrochemical Science and Technology; Urquidi-Macdonald, M. [Pennsylvania State Univ. (United States). Engineering Science and Mechanics; Engelhardt, G.R. [OLI Systems, Inc. (United States); Dooley, R.B. [Electric Power Research Inst., Palo Alto, CA (United States). Materials and Chemistry Performance Dept.

    2007-07-15

    The prediction of pitting corrosion damage on low-pressure steam turbine (LPST) blade surfaces has been investigated experimentally and the results have been interpreted in terms of the Point Defect Model (PDM) for passivity breakdown and the nucleation of pits. Experimental relationships between the critical breakdown potential (Vc) and the chloride activity aCl- and pH have demonstrated the applicability of the PDM for describing passivity breakdown on AISI Type 403 stainless steel (SS), a commonly employed blade alloy in LPSTs, in chloride-containing borate buffer solutions. The model parameter values, as determined by optimization of the PDM on passivity breakdown data, may be used to predict the nucleation and accumulation of pitting damage on LPST blades under simulated turbine shutdown conditions. In order to evaluate the predictions, integral damage functions (IDFs) and extreme value distributions in pit depth have been measured on samples taken from failed blades recovered from the field (Texas Genco). These data are being used to test the predictions of Damage Function Analysis (DFA), which is based on the PDM and on deterministic models for pit growth and delayed repassivation. However, the success of this analysis critically depends on our ability to define the corrosion evolutionary path. (orig.)

  12. INFLUENCE OF PLASMA NITRIDING ON THE CORROSION BEHAVIOUR AND ADHESION OF DLC COATINGS DEPOSITED ON AISI 420 STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Jorge N. Pecina

    2016-06-01

    Full Text Available In this work the corrosion behavior and adhesion of two DLC (“Diamond Like Carbon” films (“Soft” and “Hard” were studied. Both coatings were deposited by PACVD (“Plasma Assisted Chemical Vapour Deposition” on plasma-nitrided and non-nitrided AISI 420 stainless steel. Raman spectroscopy was conducted and surface hardness was measured. The microstructure by OM and SEM, was observed. Adhesion tests were performed with C. Rockwell indentation test. Salt Spray and immersion were performed in HCl. The “Soft” coating was 20 μm thick, the “Hard” film was about 2.5 μm. The hardness was of 500 HV in the “Soft” DLC and 1400 HV in the “Hard” DLC. Both coatings presented low friction coefficient and good adhesion when they were deposited on nitrided steel. Also presented good resistance to atmospheric corrosion. HCl DLC degradation slowed rapidly introduced uncoated samples.

  13. Influence of austenitizing temperature on microstructure and mechanical properties of AISI 431 martensitic stainless steel electron beam welds

    Energy Technology Data Exchange (ETDEWEB)

    Rajasekhar, A. [Department of Mechanical Engineering, SVITS, Mahaboob Nagar 509 001 (India)], E-mail: adula.rajasekhar@rediffmail.com; Madhusudhan Reddy, G.; Mohandas, T. [Defence Metallurgical Research Laboratory, Hyderabad 500 058 (India); Murti, V.S.R. [Department of Mechanical Engineering, SVITS, Mahaboob Nagar 509 001 (India)

    2009-05-15

    The relative effects of various austenitizing temperatures on microstructure and mechanical properties of electron beam welds of AISI 431martensitic stainless steel were studied. The post-weld heat treatments consist of austenitizing the weld samples for 1 h at various temperatures, i.e., at 950 deg. C, 1000 deg. C, 1050 deg. C, 1100 deg. C and at 1150 deg. C and air cooling followed by double tempering, i.e., tempering at 670 + 600 deg. C. In the as-welded condition the microstructure contains dendritic structure with ferrite network and retained austenite in a matrix of un-tempered martensite. The prior austenite grain size increased with increase in austenitizing temperature. Parent metal grain size was coarser as compared to grain size in the weld zone in respective conditions. Retained austenite content increased with increase in the austenitizing temperature. Presence of undissolved carbides was observed in welds and parent metal austenitized up to 1000 deg. C and they dissolved at austenitizing temperature {>=} 1050 deg. C. Coarsening of martensite laths was observed after tempering. The martensite laths were coarser in the samples subjected to higher austenitizing temperatures. Optimum mechanical properties, i.e., strength, hardness and toughness were observed when austenitized between 1050 deg. C and 1100 deg. C followed by tempering. Austenitizing at 1150 deg. C and tempering resulted in inferior mechanical properties. The mechanism for the observed trends is discussed in relation to the microstructure, fracture features and mechanical properties.

  14. In vitro response of human peripheral blood mononuclear cells to AISI 316L austenitic stainless steel subjected to nitriding and collagen coating treatments.

    Science.gov (United States)

    Stio, Maria; Martinesi, Maria; Treves, Cristina; Borgioli, Francesca

    2015-02-01

    Surface modification treatments can be used to improve the biocompatibility of austenitic stainless steels. In the present research two different modifications of AISI 316L stainless steel were considered, low temperature nitriding and collagen-I coating, applied as single treatment or in conjunction. Low temperature nitriding produced modified surface layers consisting mainly of S phase, which enhanced corrosion resistance in PBS solution. Biocompatibility was assessed using human peripheral blood mononuclear cells (PBMC) in culture. Proliferation, lactate dehydrogenase (LDH) levels, release of cytokines (TNF-α, IL-1β, IL-12, IL-10), secretion of metalloproteinase (MMP)-9 and its inhibitor TIMP-1, and the gelatinolytic activity of MMP-9 were determined. While the 48-h incubation of PBMC with all the sample types did not negatively influence cell proliferation, LDH and MMP-9 levels, suggesting therefore a good biocompatibility, the release of the pro-inflammatory cytokines was always remarkable when compared to that of control cells. However, in the presence of the nitrided and collagen coated samples, the release of the pro-inflammatory cytokine IL-1β decreased, while that of the anti-inflammatory cytokine IL-10 increased, in comparison with the untreated AISI 316L samples. Our results suggest that some biological parameters were ameliorated by these surface treatments of AISI 316L.

  15. The Effect of NiAI Coatings on Oxidation Behavior of AISI 403 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    M.Ebrahimianl; F.Ashrafizadeh

    2004-01-01

    This paper reports the oxidation behavior of stainless steel type 403 as a substrate material with and without NiAl coating. Evaluation of oxidation resistance was performed on uncoated and coated specimens at 850 and 1050℃. Acommercial diffusion process was used for the formation of NiA1 intermetallic coatings on the specimens. Before aluminizing, a layer of nickel, about 40μm, was deposited on specimens by electroplating. Various techniques including SEM, EDAX, optical microscopy and micro-hardness testing were employed to investigate the coatings before and after oxidation tests. Nickel-aluminides produced by two stage; plating-aluminizing, treatment with NiA1 on the surface increased the performance of stainless steel samples significantly.

  16. The Effect of NiAl Coatings on Oxidation Behavior of AISI 403 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    M. Ebrahimian; F. Ashrafizadeh

    2004-01-01

    This paper reports the oxidation behavior of stainless steel type 403 as a substrate material with and without NiAl coating. Evaluation of oxidation resistance was performed on uncoated and coated specimens at 850 and 1050℃. A commercial diffusion process was used for the formation of NiAl intermetallic coatings on the specimens. Before aluminizing, a layer of nickel, about 40 μm, was deposited on specimens by electroplating. Various techniques including SEM, EDAX, optical microscopy and micro-hardness testing were employed to investigate the coatings before and after oxidation tests. Nickel-aluminides produced by two stage; plating-aluminizing, treatment with NiAl on the surface increased the performance of stainless steel samples significantly.

  17. Effect of Surface Treatment on the Surface Characteristics of AISI 316L Stainless Steel

    Science.gov (United States)

    Trigwell, Steve; Selvaduray, Guna

    2005-01-01

    The ability of 316L stainless steel to maintain biocompatibility, which is dependent upon the surface characteristics, is critical to its effectiveness as an implant material. The surfaces of mechanically polished (MP), electropolished (EP) and plasma treated 316L stainless steel coupons were characterized by X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) for chemical composition, Atomic Force Microscopy for surface roughness, and contact angle measurements for critical surface tension. All surfaces had a Ni concentration that was significantly lower than the bulk concentration of -43%. The Cr content of the surface was increased significantly by electropolishing. The surface roughness was also improved significantly by electropolishing. Plasma treatment had the reverse effect - the surface Cr content was decreased. It was also found that the Cr and Fe in the surface exist in both the oxide and hydroxide states, with the ratios varying according to surface treatment.

  18. Multitechnique characterisation of 304L surface states oxidised at high temperature in steam and air atmospheres

    Science.gov (United States)

    Mamede, Anne-Sophie; Nuns, Nicolas; Cristol, Anne-Lise; Cantrel, Laurent; Souvi, Sidi; Cristol, Sylvain; Paul, Jean-François

    2016-04-01

    In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8-12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol deposition mechanisms. To be able to understand the nature of interactions between these FPs and the RCS surfaces, a preliminary step is to characterize the RSC surface states in steam and air atmosphere at high temperatures. Pieces of 304L stainless steel have been treated in a flow reactor at two different temperatures (750 °C and 950 °C) for two different exposition times (24 h and 72 h). After surfaces analysing by a unique combination of surface analysis techniques (XPS, ToF-SIMS and LEIS), for 304L, the results show a deep oxide scale with multi layers and the outer layer is composed of chromium and manganese oxides. Oxide profiles differ in air or steam atmosphere. Fe2O3 oxide is observed but in minor proportion and in all cases no nickel is detected near the surface. Results obtained are discussed and compared with the literature data.

  19. Hot corrosion behavior of NiAl coatings on AISI 403 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimian, M. [Iranian Surface Research and Engineering Centre, Isfahan (Iran, Islamic Republic of); Moradi, M.; Partovi Rad, M.; Ashrafizadeh, F. [Isfahan Univ. of Technology, Dept. of Materials Engineering, Isfahan (Iran, Islamic Republic of)

    2003-07-01

    The present paper reports the hot corrosion behavior of Nickel-aluminized coatings and Ni-Al plasma sprayed coatings on stainless steel type 403 as a substrate material. Evaluation of corrosion resistance was achieved by furnace tests on both uncoated and coated specimens. Aluminizing and plasma spraying processes were used for deposition and formation of Ni-Al intermetallic coatings on the specimens. Before aluminizing, a layer of nickel, about 40 {mu}m, was deposited on specimens by electroplating. Various techniques including SEM, EDAX, optical microscopy and micro-hardness testing were employed to investigate the coatings before and after corrosion tests. Nickel-aluminides produced by two stage; plating-aluminizing, treatment with NiAl on the surface displayed better performance in hot corrosion tests compared with plasma sprayed coatings. (author)

  20. Microstructure of AISI 304 stainless steel strips produced by a twin-roll caster

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By optical inspection of macro-etched metallography and electron back-scattered diffraction (EBSD) mapping,this paper analyzed the microstructure of anstenitic stainless steel strips produced with an equal-diameter twin-roll strip caster.The results indicate that the microstructure of the strips includes two columnar zones with highly compact dendrites and one equiaxed zone.The characteristics,such as grain size and growing direction of columnar grains and equiaxed grains,were investigated.An additional transitional area with many freer grains between the columnar zone and the equiaxed zone was found.As shown in EBSD analysis,small angle boundaries exist both in the columnar zone and the equiaxed zone,although they are especially more in the transitional area.Additionally,some twin boundaries were found in the mierostructure of the strips.

  1. Multi performance characteristic optimization of shot peening process for AISI 304 austenitic stainless steel using grey relational analysis with principal component analysis and Taguchi method

    Directory of Open Access Journals (Sweden)

    Dr. Lakhwinder Singh

    2013-10-01

    Full Text Available Shot peening is a cold working process. It impact on thin surface layer of the material and is used to enhance the mechanical and surface properties. The manufacturer is in demand to reduce the cost and improve the process productivity. He is always in search of an optimization technique which involves multiple performance characteristics. From this work, an optimal combination of shot peening parameters is generated by using a Grey relational analysis (GRA with Principal component analysis (PCA and Taguchi method. The present study shows that there are many factors that affect the properties of the AISI 304 austenitic stainless steel. Mechanisms to compensate for surface tractions and further enhancement of mechanical properties are described. The shot peening is discussed to enhance the mechanical and surface properties of AISI 304 austenitic stainless steel. The optimization of shot pening process is done by including multi performance characteristics i.e. tensile strength, surface hardness an fatigue strengths. The analysis includes pressure, shot size, exposure time, nozzle distance and nozzle angle as process parameters. The complete analysis will be helpful to the manufacturer in deciding the shot peening parameters for required performance characteristics.

  2. Effects of surface modification of thin wires of AISI 302 stainless steel by electrolytic plasma on its mechanical properties; Efecto de la modificacion superficial de alambres delgados de acero inoxidable AISI 302 mediante plasma electrolitico sobre sus propiedades mecanicas

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, A.; Camurri, C.; Carrasco, C.; Soldera, F.

    2012-07-01

    In this work different tests using electrolytic plasma (EP) on thin wires of stainless steel AISI 302 in an inert solution were performed. Tensile tests were carried out in order to measure changes in the mechanical strength of the samples; moreover, both the morphological and microstructural changes also were evaluated. It was found that after 10 s of the application of EP, the samples surface was uniformly covered by nodules-like and craters similar to those found in the melting and cooling periods of EP. The results show a significant surface grain refinement, leading to crystalline arrangements with sizes less than 200 nm and also an increase in the samples tensile strength of at least 57 % respect to steel base. (Author) 14 refs.

  3. Applications of the essay at slow deformation velocity in pipes of stainless steel AISI-304; Aplicaciones del ensayo a velocidad de deformacion lenta en tuberias de acero inoxidable AISI-304

    Energy Technology Data Exchange (ETDEWEB)

    Zamora R, L.; Mora R, T. De la [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    Nowadays is carried out research related with the degradation mechanisms of structures, systems and/or components in the nuclear power plants, since many of the involved processes are those responsible for the dependability of these, of the integrity of the components and of the aspects of safety. The purpose of this work, was to determine the grade of susceptibility to the corrosion of a pipe of Austenitic stainless steel AISI 304, in a solution of Na CI (3.5%) to the temperatures of 60 and 90 C, in two different thermal treatments - 1. - Sensitive 650 C by 4 hours and cooled in water. 2. Solubilized to 1050 C by 1 hour and cooled in water.

  4. Effects of nitrogen and pulsed mean welding current in AISI 316 austenitic stainless steel solidification cracks; Efecto del nitrogeno y la corriente media pulsada de soldadura en la formacion de grietas de solidificacion en aceros inoxidables AISI 316L

    Energy Technology Data Exchange (ETDEWEB)

    Trevisan, R. E.; Braga, E.; Fals, H. C.

    2002-07-01

    An analysis of the influence of nitrogen concentration in the weld zone and the pulsed mean welding current in the solidification crack formation is presented in this paper. The AISI 316L austenitic stainless steel was employed as the metal base. The welding was done using CC+ pulsed flux cored are welding process and AWS E316L wire type. The tests were conducted using CO{sub 2} shielding gas with four different nitrogen levels (0,5; 10 and 15%) in order to induce different nitrogen weld metal concentrations. The pulsed mean welding current was varied in three levels and the. Transvarestraint tangential strain test was fixed of 5%. The results showed that the solidification cracking decreased as the pulsed mean welding current increase. It was also verified that an increase of the weld zone nitrogen level was associated with a decrease in both the total length of solidification crack and the amount of {delta} ferrite. (AUthor) 20 refs.

  5. Characterization of Plasma Nitrocarburized Layers Produced on AISI 316L Stainless Steel%AISI 316L不锈钢等离子氮碳共渗层的表征

    Institute of Scientific and Technical Information of China (English)

    L. C. Casteletti; F. A. P. Fernandes; A. Lombardi-Neto; C. A. Picon; G. Tremiliosi-Filho; G. E. Totten

    2009-01-01

    Hardness and consequently wear resistance of austenitic stainless steel can be highly increased, without loosing corrosion resistance by producing plasma nitrocarburizing surface layers. In this work, a AISI 316L stainless steel plasma nitrocarburized at 450℃, and the obtained layers were characterized by optical microscopy, micro-hardness and micro-wear tests. It was verified that the layer is composed by chromium nitrides precipitates and essentially expanded austenite nitrogen rich and with hardness around 850 HV. The total average thickness of the layer was about 45 μm, presenting good uniformity. Its wear resistance was much higher than that of the sub-strate.%奥氏体不锈钢通过等离子氮碳共渗可显著提高其表面硬度,从而提高耐磨性而又不损害其抗腐蚀性能.本文采用光学显微镜、显微硬度和微磨损试验对经于450℃等离子氮碳共渗的AISI 316L不锈钢和所获得的渗层进行了表征.结果证明,等离子氮碳共渗层由氮化铬析出相和富氮奥氏体基体组成,其硬度约850 HV;渗层总深度平均约为45 μm,且很均匀;渗层的耐磨性大大高于基体.

  6. Effect of low temperature plasma hardening treatment on microstructure and properties of AISI 420 stainless steel%低温离子硬化处理对 AISI 420不锈钢组织与性能的影响

    Institute of Scientific and Technical Information of China (English)

    杜威; 赵程

    2014-01-01

    研究了低温离子渗氮、离子氮碳共渗和离子渗碳硬化处理对AISI 420马氏体不锈钢的显微组织、表面硬度、耐蚀性、耐磨性的影响。结果表明,离子渗氮、氮碳共渗和离子渗碳处理都可提高马氏体不锈钢的表面硬度;经不同工艺处理后的试样,除500℃×4 h渗氮工艺外,其他不锈钢试样表面的耐蚀性均未出现明显降低,当渗氮温度过高(500℃)时,由于CrN的析出使得渗氮层的耐蚀性显著下降;磨损试验的结果表明,离子渗碳处理后硬化层的耐磨性最佳。%Effect of low temperature plasma nitriding , nitrocarburizing and carburizing on microstructure , surface hardness , corrosion resistance and wear resistance of AISI 420 martensitic stainless steel was investigated . The results show that plasma nitriding , nitrocarburizing and carburizing process can increase the surface hardness .There is no significantly decrease to the corrosion resistance on the surface of Stainless steel treated by different treatment processes except of plasma nitriding at 500℃for 4 h.If the nitriding temperature is higher than 500℃, the corrosion resistance will significantly decline due to the precipitation of CrN .The wear results show that hardened layer of plasma carburizing sample has the best wear resistance .

  7. Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jiang; Zhuo Chengzhi; Tao Jie; Liu Linlin [Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China); Jiang Shuyun [Department of Mechanical Engineering, Southeast University, 2 Sipailou, Nanjing 210096 (China)], E-mail: xujiang73@nuaa.edu.cn

    2009-01-07

    In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO{sub 2} predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 deg. C) conditions, amorphous nano-SiO{sub 2} particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr{sub 6.5}Ni{sub 2.5}Si and Cr{sub 23}C{sub 6}. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO{sub 2} particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix

  8. Low-Temperature Nitriding of Deformed Austenitic Stainless Steels with Various Nitrogen Contents Obtained by Prior High-Temperature Solution Nitriding

    Science.gov (United States)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas L.; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2016-08-01

    In the past decades, high nitrogen steels (HNS) have been regarded as substitutes for conventional austenitic stainless steels because of their superior mechanical and corrosion properties. However, the main limitation to their wider application is their expensive production process. As an alternative, high-temperature solution nitriding has been applied to produce HNS from three commercially available stainless steel grades (AISI 304L, AISI 316, and EN 1.4369). The nitrogen content in each steel alloy is varied and its influence on the mechanical properties and the stability of the austenite investigated. Both hardness and yield stress increase and the alloys remain ductile. In addition, strain-induced transformation of austenite to martensite is suppressed, which is beneficial for subsequent low-temperature nitriding of the surface of deformed alloys. The combination of high- and low-temperature nitriding results in improved properties of both bulk and surface.

  9. Study of cyclic oxidation for stainless steels AISI 309 T 253 M A, with low additions of cerium; Estudio de la oxidacion ciclica de los aceros inoxidables AISI 309 T 253 MA, con pequenas adiciones de Cerio

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez F, G.L.; Martinez, M.; Ruiz, A. [Universidad Nacional Experimental Politecnica (UNEXPO) - Vicerrectorado de Puerto Ordaz, Centro de Estudios de Corrosion. Puerto Ordaz. venezuela (Venezuela)

    1998-12-31

    It has been detected that the addition of small amounts (<1%) of the so called `reactive elements` such as Cerium to Fe-Cr alloys that was utilized in oxidating environment at high temperatures improving its resistance to oxidation under isothermal and cyclic conditions. In this work, it was evaluated the behavior under cyclic oxidation conditions for an austenitic stainless steel at chromium-nickel (253MA) with cerium addition, and comparing it with the AISI 310S austenitic stainless steel. The cyclic oxidation essays consist of five cycles by 24 hours each one, following of a cooling in air until ambient temperature from the temperatures of 850, 900 and 950 Centigrade, registering the gain mass of the specimen at end of each cycle. In order to this were prepared samples with dimensions of 20 mm. x 10 mm. x 1 mm. Later to the oxidation essays was evaluated the morphology of the corrosion products layer by scanning electron microscopy. The present phases were identified by X-ray diffraction and by chemical microanalysis by Dispersive energy (EDAX). The results obtained show that the steel with cerium addition, presents a higher adherence and resistance to the spalling noting that the cerium promotes the casting anchor of the oxides layer to matrix and by reducing the grain size of the layer improving its plasticity. Additionally the cerium promotes the preferential oxidation of the forming elements of protective layers like the chromium. (Author)

  10. Effect of Continuous and Pulsed Current Gas Tungsten Arc Welding on Dissimilar Weldments Between Hastelloy C-276/AISI 321 Austenitic Stainless Steel

    Science.gov (United States)

    Sharma, Sumitra; Taiwade, Ravindra V.; Vashishtha, Himanshu

    2017-02-01

    In the present investigation, an attempt has been made to join Hastelloy C-276 nickel-based superalloy and AISI 321 austenitic stainless steel using ERNiCrMo-4 filler. The joints were fabricated by continuous and pulsed current gas tungsten arc welding processes. Experimental studies to ascertain the structure-property co-relationship with or without pulsed current mode were carried out using an optical microscope and scanning electron microscope. Further, the energy-dispersive spectroscope was used to evaluate the extent of microsegregation. The microstructure of fusion zone was obtained as finer cellular dendritic structure for pulsed current mode, whereas columnar structure was formed with small amount of cellular structure for continuous current mode. The scanning electron microscope examination witnessed the existence of migrated grain boundaries at the weld interfaces. Moreover, the presence of secondary phases such as P and μ was observed in continuous current weld joints, whereas they were absent in pulsed current weld joints, which needs to be further characterized. Moreover, pulsed current joints resulted in narrower weld bead, refined morphology, reduced elemental segregation and improved strength of the welded joints. The outcomes of the present investigation would help in obtaining good quality dissimilar joints for industrial applications and AISI 321 ASS being cheaper consequently led to cost-effective design also.

  11. Microstructure, Strength, and Fracture Topography Relations in AISI 316L Stainless Steel, as Seen through a Fractal Approach and the Hall-Petch Law

    Directory of Open Access Journals (Sweden)

    Oswaldo Antonio Hilders

    2015-01-01

    Full Text Available The influence of the fracture surface fractal dimension DF and the fractal dimension of grain microstructure DM on the strength of AISI 316L type austenitic stainless steel through the Hall-Petch relation has been studied. The change in complexity experimented by the net of grains, as measured by DM, is translated into the respective fracture surface irregularity through DF, in such a way that the higher the grain size (lower DM values the lower the fracture surface roughness (lower values of DF and the shallower the dimples on the fractured surfaces. The material was heat-treated at 904, 1010, 1095, and 1194°C, in order to develop equiaxed grain microstructures and then fractured by tension at room temperature. The fracture surfaces were analyzed with a scanning electron microscope, DF was determined using the slit-island method, and the values of DM were taken from the literature. The relation between grain size, DM, mechanical properties, and DF, developed for AISI 316L steel, could be generalized and therefore applied to most of the common micrograined metal alloys currently used in many key engineering areas.

  12. Effect of Continuous and Pulsed Current Gas Tungsten Arc Welding on Dissimilar Weldments Between Hastelloy C-276/AISI 321 Austenitic Stainless Steel

    Science.gov (United States)

    Sharma, Sumitra; Taiwade, Ravindra V.; Vashishtha, Himanshu

    2017-03-01

    In the present investigation, an attempt has been made to join Hastelloy C-276 nickel-based superalloy and AISI 321 austenitic stainless steel using ERNiCrMo-4 filler. The joints were fabricated by continuous and pulsed current gas tungsten arc welding processes. Experimental studies to ascertain the structure-property co-relationship with or without pulsed current mode were carried out using an optical microscope and scanning electron microscope. Further, the energy-dispersive spectroscope was used to evaluate the extent of microsegregation. The microstructure of fusion zone was obtained as finer cellular dendritic structure for pulsed current mode, whereas columnar structure was formed with small amount of cellular structure for continuous current mode. The scanning electron microscope examination witnessed the existence of migrated grain boundaries at the weld interfaces. Moreover, the presence of secondary phases such as P and μ was observed in continuous current weld joints, whereas they were absent in pulsed current weld joints, which needs to be further characterized. Moreover, pulsed current joints resulted in narrower weld bead, refined morphology, reduced elemental segregation and improved strength of the welded joints. The outcomes of the present investigation would help in obtaining good quality dissimilar joints for industrial applications and AISI 321 ASS being cheaper consequently led to cost-effective design also.

  13. Cultures and co-cultures of human blood mononuclear cells and endothelial cells for the biocompatibility assessment of surface modified AISI 316L austenitic stainless steel.

    Science.gov (United States)

    Stio, Maria; Martinesi, Maria; Treves, Cristina; Borgioli, Francesca

    2016-12-01

    Samples of AISI 316L austenitic stainless steel were subjected either to grinding and polishing procedure, or to grinding and then low temperature glow-discharge nitriding treatment, or to grinding, nitriding and subsequently coating with collagen-I. Nitrided samples, even if only ground, show a higher corrosion resistance in PBS solution, in comparison with ground and polished AISI 316L. Biocompatibility was evaluated in vitro by incubating the samples with either peripheral blood mononuclear cells (PBMC) or human umbilical vein endothelial cells (HUVEC), tested separately or in co-culture. HUVEC-PBMC co-culture and co-incubation of HUVEC with PBMC culture medium, after the previous incubation of PBMC with metallic samples, allowed to determine whether the incubation of PBMC with the different samples might affect HUVEC behaviour. Many biological parameters were considered: cell proliferation, release of cytokines, matrix metalloproteinases (MMPs) and sICAM-1, gelatinolytic activity of MMPs, and ICAM-1 protein expression. Nitriding treatment, with or without collagen coating of the samples, is able to ameliorate some of the biological parameters taken into account. The obtained results point out that biocompatibility may be successfully tested in vitro, using cultures of normal human cells, as blood and endothelial cells, but more than one cell line should be used, separately or in co-culture, and different parameters should be determined, in particular those correlated with inflammatory phenomena.

  14. Multi-Objective Optimization ( Surface Roughness & Material Removal Rate of Aisi 202 Grade Stainless Steel in Cnc Turning Using Extended Taguchi Method And Grey Analysis

    Directory of Open Access Journals (Sweden)

    Er.Ankush Aggarwal

    2014-07-01

    Full Text Available The present study applied Taguchi method through a case study in straight turning of AISI 202 stainless steel bar on CNC Machine ( Mfd by ACE DESIGNERS using Titanium Carbide tool for the optimization of Material removal rate, Surface Roughness and tool wear process parameter.The study aimed at evaluating the best process environment which could simultaneously satisfy requirements of both quality as well as productivity with special emphasis on maximizing material removal rate and minimizing surface roughness and tool flank wear at various combination of cutting speed, feed, depth of cut. The predicted optimal setting ensured maximum MRR and minimum surface roughness and tool wear. Since optimum material removal rate is desired, so higher the better criteria of Taguchi signal to noise ratio is used for MRR – SNs = -10 log(Sy2 /n

  15. EXAMINATION OF THE CUTTING FORCES OF AISI 304 AUSTENITIC STAINLESS STEEL IN THE TURNING PROCESS WITH TITANIUM CARBIDE COATED CUTTING TOOLS

    Directory of Open Access Journals (Sweden)

    Özgür TEKASLAN

    2007-02-01

    Full Text Available In this study, cutting forces occurring in the machining process of AISI 304 austenitic stainless steel specimen using titanium coated cutting tools are investigated experimentally and the results are compared to theoretical calculations. In the experimental study, various cutting speeds, feed rates and cutting depths are considered. Cutting forces are measured by 3-dimensional Kistler dynamometer. In the theoretically study, cutting forces are determined by Kienzle formulation. Consequently, it is found that the calculation of cutting forces in the theoretical method doesn't yield the exact results because of various factors and there is a % 25 average differences in accordance with the experimental results. Hence it is evaluated that the experimental technique in the determination of cutting forces yields more accurate results.

  16. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  17. On the corrosion resistance of AISI 316L-type stainless steel coated with manganese and annealed with flow of oxygen

    Science.gov (United States)

    Savaloni, Hadi; Agha-Taheri, Ensieh; Abdi, Fateme

    2016-06-01

    AISI 316L-type stainless steel was coated with 300-nm-thick Mn thin films and post-annealed at 673 K with a constant flow of oxygen (250 cm3/min). The films crystallographic and morphological structures were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM) before corrosion test and scanning electron microscopy (SEM) after corrosion test. Corrosion behavior of the samples in 0.3, 0.5 and 0.6 M NaCl solutions was investigated by means of potentiodynamic and electrochemical impedance spectroscopy (EIS) techniques. Results showed that the corrosion inhibition of annealed Mn/SS316L in all NaCl solutions with different concentrations is higher than that of bare SS316L. A correlation is achieved between the structural variation of the films with the potentiodynamic and EIS corrosion results.

  18. Effects of Cold Rolling and Strain-Induced Martensite Formation in a SAF 2205 Duplex Stainless Steel

    Science.gov (United States)

    Breda, Marco; Brunelli, Katya; Grazzi, Francesco; Scherillo, Antonella; Calliari, Irene

    2015-02-01

    Duplex stainless steels (DSSs) are biphasic steels having a ferritic-austenitic microstructure that allows them to combine good mechanical and corrosion-resistance properties. However, these steels are sensitive to microstructural modifications, such as ferrite decomposition at high temperatures and the possibility of strain-induced martensite (SIM) formation from cold-worked austenite, which can significantly alter their interesting features. In the present work, the effects of cold rolling on the developed microstructural features in a cold-rolled SAF 2205 DSS and the onset of martensitic transformation are discussed. The material was deformed at room temperature from 3 to 85 pct thickness reduction, and several characterization techniques (scanning and transmission electron microscopy, X-ray diffraction, hardness measurements, and time-of-flight-neutron diffraction) were employed in order to fully describe the microstructural behavior of the steel. Despite the low stacking fault energy of DSS austenite, which contributed to SIM formation, the steel was found to be more stable than other stainless steel grades, such as AISI 304L. Rolling textures were similar to those pertaining to single-phase materials, but the presence of the biphasic (Duplex) microstructure imposed deformation constraints that affected the developed microstructural features, owing to phases interactions. Moreover, even if an intensification of the strain field in austenite was revealed, retarded SIM transformation kinetics and lower martensite amounts with respect to AISI 304L were observed.

  19. Investigation of the Mechanical Properties of AISI 316 Austenitic Stainless Steel and St 37 Low Carbon Steel Dissimilar Joint by Friction Stir Welding

    Directory of Open Access Journals (Sweden)

    A.H. Khosrovaninezhad

    2015-07-01

    Full Text Available This paper reports on the mechanical properties of the dissimilar joints between AISI 316 austenitic stainless steel and St 37 low carbon steel achieved using friction stir welding technique. The welding was carried out by means of rotational speed of 800 rpm and linear speeds of 50,100,150 mm/min. EDS and XRD techniques were employed in order to determine possible phase transformations. Tensile test, shear punch test and microhardness measurements were conducted to evaluate the mechanical properties of the joints. The results of phase investigations showed that no carbide and brittle phase were detected at the joint boundary. Also, tensile test results demonstrated that failure occurred in the St 37 base metal. According to the shear punch test, the highest ultimate shear strength and yield shear strength was achieved for the sample welded at rotational speed of 800 rpm and linear speed of 150 mm/min, while this sample showed the least elongation. In addition, the highest microhardness was measured in the stir zone of austenitic stainless steel sample welded in the above mentioned welding condition, which can be attributed to the decrease in grain size caused by recrystallization process.

  20. Reverse Transformation of Deformation-Induced Phases and Associated Changes in the Microstructure of Explosively Clad Ti-5Ta-2Nb and 304L SS

    Science.gov (United States)

    Prasanthi, T. N.; Sudha, C.; Murugesan, S.; Thomas Paul, V.; Saroja, S.

    2015-10-01

    Ti-5Ta-2Nb alloy was joined to 304L austenitic stainless steel by explosive cladding technique. Explosive cladding resulted in the formation of deformation-induced martensite in 304L SS and fcc phase of Ti in the Ti-5Ta-2Nb side of the joint. The stability of these metastable phases was systematically studied using high-temperature X-ray diffraction technique and transmission electron microscopy, which enabled the optimization of the temperature window for post-cladding heat treatments.

  1. Deformation induced martensite in an AISI 301LN stainless steel: characterization and influence on pitting corrosion resistance

    OpenAIRE

    Hamilton Ferreira Gomes de Abreu; Sheyla Santana de Carvalho; Pedro de Lima Neto; Ricardo Pires dos Santos; Válder Nogueira Freire; Paulo Maria de Oliveira Silva; Sérgio Souto Maior Tavares

    2007-01-01

    In austenitic stainless steels, plastic deformation can induce martensite formation. The induced martensite is related to the austenite (gamma) instability at temperatures close or below room temperature. The metastability of austenite stainless steels increases with the decreasing of stacking fault energy (SFE). In this work, the deformation induced martensite was analyzed by X ray diffraction, electron back scatter diffraction (EBSD), magnetic methods and atomic force microscope (AFM) in sa...

  2. Corrosion resistance of AISI 304 and 444 stainless steel pipes in sanitizing solutions of clean-in-place process

    OpenAIRE

    Lins,Vanessa de Freitas Cunha; Gonçalves,Giselle Aline dos Santos; Leão,Tiago Paschoalin; Soares,Renata Braga; Costa,Cíntia Gonçalves Fonseca; Viana,Adolfo Kalergis do Nascimento

    2016-01-01

    Stainless steel (SS) is successfully used in food industries due to the characteristics of its surface, which is essential for the maintenance of the properties of food. Tanks and stainless steel pipes, which come into direct contact with food and drink, undergo a process of cleaning and disinfecting called CIP (Clean-in-Place). This method consists of automatic recirculation of a detergent solution for a controlled time followed by a rinsing with water, and finally a cleaning and sanitizing ...

  3. The specific heat loss combined with the thermoelastic effect for an experimental analysis of the mean stress influence on axial fatigue of stainless steel plain specimens

    Directory of Open Access Journals (Sweden)

    G. Meneghetti

    2014-10-01

    Full Text Available The energy dissipated to the surroundings as heat in a unit volume of material per cycle, Q, was recently proposed by the authors as fatigue damage index and it was successfully applied to correlate fatigue data obtained by carrying out fully reversed stress- and strain-controlled fatigue tests on AISI 304L stainless steel plain and notched specimens. The use of the Q parameter to analyse the experimental results led to the definition of a scatter band having constant slope from the low- to the high-cycle fatigue regime. In this paper the energy approach is extended to analyse the influence of mean stress on the axial fatigue behaviour of unnotched cold drawn AISI 304L stainless steel bars. In view of this, stress controlled fatigue tests on plain specimens at different load ratios R (R=-1; R=0.1; R=0.5 were carried out. A new energy parameter is defined to account for the mean stress effect, which combines the specific heat loss Q and the relative temperature variation due to the thermoelastic effect corresponding to the achievement of the maximum stress level of the stress cycle. The new two-parameter approach was able to rationalise the mean stress effect observed experimentally. It is worth noting that the results found in the present contribution are meant to be specific for the material and testing condition investigated here.

  4. Decomposition of Expanded Austenite in AISI 316 L Stainless Steel Nitrided at 450 ℃%450℃渗氮AISI 316 L不锈钢中膨胀奥氏体的分解

    Institute of Scientific and Technical Information of China (English)

    F.A.P.Fernandes; L.C.Casteletti; G.E.Totten; J.Gallego

    2014-01-01

    Expanded austenite (γN ),which can be produced during plasma nitriding of austenitic stainless steels, provides high levels of strength,toughness and corrosion resistance by comparison with traditional nitride layers. However,expanded austenite properties can be lost due to decomposition caused its thermodynamic metastability. In the present work,austenitic stainless AISI 316L steel was plasma nitrided at 450 ℃ for 5 h at 500 Pa and microstructurally characterised by X-ray diffraction (XRD ),and optical and transmission electron microscopy (TEM)which confirmed the presence of fcc expanded austenite with a lattice parameter up to 9.5% larger than untreated austenite.TEM analyses of thin foils showed that fine nitrides were formed in the N layer and some areas were observed with a singular lamellar morphology very similar to the pearlite colonies found in carbon steels. Selected area electron diffraction (SAED)analysis suggests that these areas are composed of bcc ferrite and cubic chromium nitrides produced after a localised decomposition of the expanded austenite layer.Amorphous expanded austenite was observed in some areas of the investigated samples.The occurrence of N decomposition was associated with microsegregation of ferrite stabilisers (Cr,Mo)and depletion of an austenite stabiliser (Ni)in localised regions of the expanded austenite layer.%奥氏体不锈钢等离子渗氮时会形成膨胀奥氏体(γN),其强度、韧性和耐蚀性均高于传统的氮化物层。然而,膨胀奥氏体在热力学上是亚稳的,其性能会因其发生分解而降低。本文对AISI 316L 不锈钢进行了等离子渗氮,工艺为450℃×5 h,压力500 Pa。对渗氮后试样采用XRD、OM和TEM等进行了显微组织表征。试验结果证明了面心立方膨胀奥氏体的存在,其晶格常数比未经渗氮奥氏体增加多达9.5%。薄片试样的TE M分析表明,N层中有细小的氮化物形成,并且发现一些区域呈奇特的

  5. Feasibility of surface-coated friction stir welding tools to join AISI 304 grade austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    A.K. LAKSHMINARAYANAN; C.S.RAMACHANDRAN; V.BALASUBRAMANIAN

    2014-01-01

    An attempt is made to develop the tools that are capable enough to withstand the shear, impact and thermal forces that occur during friction stir welding of stainless steels. The atmospheric plasma spray and plasma transferred arc hardfacing processes are employed to deposit refractory ceramic based composite coatings on the Inconel 738 alloy. Five different combinations of self-fluxing alloy powder and 60% ceramic rein-forcement particulate mixtures are used for coating. The best friction stir welding tool selected based on tool wear analysis is used to fabricate the austenitic stainless steel joints.

  6. Finite Element Modeling and Validation of Residual Stresses in 304 L Girth Welds

    Energy Technology Data Exchange (ETDEWEB)

    Dike, J.J.; Ortega, A.R.; Cadden, C.H.; Rangaswamy, P. Brown, D.

    1998-06-01

    Three dimensional finite element simulations of thermal and mechanical response of a 304 L stainless steel pipe subjected to a circumferential autogenous gas tungsten arc weld were used to predict residual stresses in the pipe. Energy is input into the thermal model using a volumetric heat source. Temperature histories from the thermal analysis are used as loads in the mechanical analyses. In the mechanical analyses, a state variable constitutive model was used to describe the material behavior. The model accounts for strain rate, temperature, and load path histories. The predicted stresses are compared with x-ray diffraction determinations of residual stress in the hoop and circumferential directions on the outside surface of the pipe. Calculated stress profiles fell within the measured data. Reasons for observed scatter in measured stresses are discussed.

  7. The effect of CO{sub 2} laser beam welded AISI 316L austenitic stainless steel on the viability of fibroblast cells, in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Köse, Ceyhun, E-mail: ceyhun.kose@gop.edu.tr [Faculty of Natural Sciences and Engineering, Department of Mechanical Engineering, Gaziosmanpaşa University, Tokat (Turkey); Kaçar, Ramazan, E-mail: rkacar@karabuk.edu.tr [Faculty of Technology Department of Manufacturing Engineering, Karabuk University, Karabuk 78050 (Turkey); Zorba, Aslı Pınar, E-mail: aslipinarzorba@gmail.com [Graduate School of Natural and Applied Sciences, Department of Bioengineering Cell Culture and Tissue Engineering, Yıldız Technical University, Istanbul (Turkey); Bağırova, Melahat, E-mail: mbagir@yildiz.edu.tr [Department of Bioengineering Cell Culture and Tissue Engineering, Yıldız Technical University, Istanbul (Turkey); Allahverdiyev, Adil M., E-mail: adil@yildiz.edu.tr [Department of Bioengineering Cell Culture and Tissue Engineering, Yıldız Technical University, Istanbul (Turkey)

    2016-03-01

    It has been determined by the literature research that there is no clinical study on the in vivo and in vitro interaction of the cells with the laser beam welded joints of AISI 316L biomaterial. It is used as a prosthesis and implant material and that has adequate mechanical properties and corrosion resistance characteristics. Therefore, the interaction of the CO{sub 2} laser beam welded samples and samples of the base metal of AISI 316L austenitic stainless steel with L929 fibroblast cells as an element of connective tissue under in vitro conditions has been studied. To study the effect of the base metal and the laser welded test specimens on the viability of the fibroblast cells that act as an element of connective tissues in the body, they were kept in DMEMF-12 medium for 7, 14, 28 days and 18 months. The viability study was experimentally studied using the MTT method for 7, 14, 28 days. In addition, the direct interaction of the fibroblast cells seeded on 6 different plates with the samples was examined with an inverted microscope. The MTT cell viability experiment was repeated on the cells that were in contact with the samples. The statistical relationship was analyzed using a Tukey test for the variance with the GraphPad statistics software. The data regarding metallic ion release were identified with the ICP-MS method after the laser welded and main material samples were kept in cell culture medium for 18 months. The cell viability of the laser welded sample has been detected to be higher than that of the base metal and the control based on 7th day data. However, the laser welded sample's viability of the fibroblast cells has diminished by time during the test period of 14 and 28 days and base metal shows better viability when compared to the laser welded samples. On the other hand, the base metal and the laser welded sample show better cell viability effect when compared to the control group. According to the ICP-MS results of the main material and

  8. Comportamiento termomecánico de aceros AISI 304

    Directory of Open Access Journals (Sweden)

    El Wahabi, M.

    2001-04-01

    Full Text Available The hot deformation behaviour of three AISI 304 (H, L and HP austenitic stainless steel with different carbon contents has been studied. An analysis of the parameters describing their hot flow curves was carried out. No heavy effect of the carbon content was found on most of the latter parameters. However, the work hardening and dynamic recovery behaviour showed clear differences depending on the given alloy, especially at high temperatures and low strain rates where the high carbon steel displayed larger work hardening and dynamic recovery rates than the other steels. The high purity steel (interstitial free displayed the lower stress levels as its hardening rate was slower than in the other two steels.

    Se llevó a cabo un estudio del comportamiento termomecánico de tres aceros inoxidables austeníticos tipo AISI 304 (H, L y HP con diferentes contenido en carbono, mediante la determinación de los parámetros que describen las etapas de deformación en caliente. No se notó un fuerte efecto del carbono en dichos parámetros, excepto en los que describen los procesos de endurecimiento y de restauración dinámica que muestran una cierta dependencia con la composición química, especialmente a bajos valores del parámetro de Zener-Hollomon, donde el acero de alto carbono (304H endurece y restaura más rápido que el de bajo carbono (304L, alcanzándose valores de tensión de pico similares en ambos casos. El material de alta pureza (libre de intersticiales toma valores de tensión de pico más bajos que los otros aceros, endureciendo más lentamente y con una velocidad de restauración similar a la del 304H.

  9. Simultaneous Investigation of the Effect of Advanced Thermomechanical Treatment and Repetitive Cyclic Voltammetry on the Electrochemical Behavior of AISI 430 Ferritic Stainless Steel

    Science.gov (United States)

    Vafaeian, Saeed; Fattah-alhosseini, Arash; Keshavarz, Mohsen K.; Mazaheri, Yousef

    2017-02-01

    In this study, it was revealed that the electrochemical behavior of AISI 430 ferritic stainless steel can be modified and improved to a large extent by the application of repetitive cyclic voltammetry in the anodic polarization branch of the alloy. The efficiency of this method was evaluated on the basis of the alloy grain size which is of great importance in corrosion studies. In fact, a coarse grain structure versus a fine grain structure was the subject of the used surface treatment method. Coarsening and refining of the grain size were conducted through a heat treatment and an advanced thermomechanical process. On the basis of cyclic voltammetry tests and also the electrochemical tests performed after that, it was shown that cyclic voltammetry had a significant improving effect on the passive behavior of both fine- and coarse-grained samples. Moreover, superior behavior of fine-grained sample in comparison with coarse-grained one was distinguished by its smaller cyclic voltammogram loops, more noble free potentials, larger capacitive arcs in the Nyquist plots, and less charge carrier densities within the passive film.

  10. Statistical analysis of AISI304 austenitic stainless steel machining using Ti(C, N/Al2O3/TiN CVD coated carbide tool

    Directory of Open Access Journals (Sweden)

    Sofiane Berkani

    2015-09-01

    Full Text Available The present research work investigated the machining of AISI304 austenitic stainless steel in terms of machining force evolution, power consumption, specific cutting force and surface roughness where a factorial experiment design and analysis of variance technique were used and several factors were evaluated for their effects on each level. The case of dry turning process was studied based on design of experiments in order to obtain empirical equations characterizing material machinability according to cutting conditions such as cutting speed, feed rate and depth of cut and the latter ones were put in relationship with the machining output variables (Ra, Fc, Kc and Pc through the response surface methodology (RSM. Results revealed that feed rate was the most preponderant factor affecting surface roughness (71.04%. However, the depth of cut affects considerably cutting force and cutting power by (60.74% and 67.11%, respectively. In addition, the specific cutting force was found affected significantly by cutting speed with a contribution of 41.43%. The quadratic model of RSM associated with response optimization technique and composite desirability was used to find optimum values of machining parameters (104.54 m/min, 0.08 mm/rev and 0.295 mm.

  11. Analysis of correlations of multiple-performance characteristics for optimization of CO2 laser nitrogen cutting of AISI 304 stainless steel

    Directory of Open Access Journals (Sweden)

    Miloš Madić

    2014-07-01

    Full Text Available The identification of laser cutting conditions for satisfying different requirements such as improving cut quality characteristics and material removal rate is of great importance. In this paper, an attempt has been made to develop mathematical models in order to relate laser cutting parameters such as the laser power, cutting speed, assist gas pressure and focus position, and cut quality characteristics such as the surface roughness, kerf width and width of heat affected zone (HAZ. A laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of laser cutting parameters considered. 3 mm thick AISI 304 stainless steel was used as workpiece material. Mathematical models were developed using a single hidden layer artificial neural network (ANN trained with the Levenberg– Marquardt algorithm. On the basis of the developed ANN models the effects of the laser cutting parameters on the cut quality characteristics were presented. It was observed that laser cutting parameters variously affect cut quality characteristics. Also, for the range of operating conditions considered in the experiment, laser cut quality operating diagrams were shown. From these operating diagrams one can see the values of cut quality characteristics that can be achieved and subsequently select laser cutting parameter values. Furthermore, the analysis includes correlations between cut quality characteristics and material removal rate. To this aim, six trade-off operating diagrams for improving multiple responses at the same time were given.

  12. Thermally Nitrided Stainless Steels for Polymer Electrolyte Membrane Fuel Cell Bipolar Plates: Part 2: Beneficial Modification of Passive Layer on AISI446

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Heli [National Renewable Energy Laboratory (NREL); Brady, Michael P [ORNL; More, Karren Leslie [ORNL; Meyer III, Harry M [ORNL; Turner, John [National Renewable Energy Laboratory (NREL)

    2004-01-01

    Thermal nitridation of AISI446 mod-1 superferritic stainless steel for 24 h at 1100 C resulted in an adherent, inward growing surface layer based on (Cr, Fe){sub 2}N{sub 1-x} (x = 0--0.5). The layer was not continuous, and although it resulted in low interfacial contact resistance (ICR) and good corrosion resistance under simulated polymer electrolyte membrane fuel cell (PEMFC) cathodic conditions; poor corrosion resistance was observed under simulated anodic conditions. Nitridation for 2 h at 1100 C resulted in little nitrogen uptake and a tinted surface. Analysis by SEM, XPS, and AES suggested a complex heterogeneous modification of the native passive oxide film by nitrogen rather than the desired microns-thick exclusive Cr-rich nitride layer. Surprisingly, this modification resulted in both good corrosion resistance under simulated cathodic and anodic conditions and low ICR, well over an order of magnitude lower than the untreated alloy. Further, little increase in ICR was observed under passivating polarization conditions. The potential of this phenomenon for PEMFC bipolar plates is discussed.

  13. Influences of deposition strategies and oblique angle on properties of AISI316L stainless steel oblique thin-walled part by direct laser fabrication

    Science.gov (United States)

    Wang, Xinlin; Deng, Dewei; Qi, Meng; Zhang, Hongchao

    2016-06-01

    Direct laser fabrication (DLF) developed from laser cladding and rapid prototyping technique has been widely used to fabricate thin-walled parts exhibiting more functions without expending weight and size. Oblique thin-walled parts accompanied with inhomogeneous mechanical properties are common in application. In the present study, a series of AISI316L stainless steel oblique thin-walled parts are successfully produced by DLF, in addition, deposition strategies, microstructure, and mechanical property of the oblique thin-walled parts are investigated. The results show that parallel deposition way is more valuable to fabricate oblique thin-walled part than oblique deposition way, because of the more remarkable properties. The hardness of high side initially increases until the distance to the substrate reaches about 25 mm, and then decreases with the increase of the deposition height. Oblique angle has a positive effect on the tensile property but a negative effect on microstructure, hardness and elongation due to the more tempering time. The maximum average ultimate tensile strength (UTS) and elongation are presented 744.3 MPa and 13.5% when the angle between tensile loading direction and horizontal direction is 45° and 90°, respectively.

  14. Simultaneous Investigation of the Effect of Advanced Thermomechanical Treatment and Repetitive Cyclic Voltammetry on the Electrochemical Behavior of AISI 430 Ferritic Stainless Steel

    Science.gov (United States)

    Vafaeian, Saeed; Fattah-alhosseini, Arash; Keshavarz, Mohsen K.; Mazaheri, Yousef

    2017-01-01

    In this study, it was revealed that the electrochemical behavior of AISI 430 ferritic stainless steel can be modified and improved to a large extent by the application of repetitive cyclic voltammetry in the anodic polarization branch of the alloy. The efficiency of this method was evaluated on the basis of the alloy grain size which is of great importance in corrosion studies. In fact, a coarse grain structure versus a fine grain structure was the subject of the used surface treatment method. Coarsening and refining of the grain size were conducted through a heat treatment and an advanced thermomechanical process. On the basis of cyclic voltammetry tests and also the electrochemical tests performed after that, it was shown that cyclic voltammetry had a significant improving effect on the passive behavior of both fine- and coarse-grained samples. Moreover, superior behavior of fine-grained sample in comparison with coarse-grained one was distinguished by its smaller cyclic voltammogram loops, more noble free potentials, larger capacitive arcs in the Nyquist plots, and less charge carrier densities within the passive film.

  15. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: crazyfim@gmail.com [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); López-Morelos, V.H., E-mail: vhlopez@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); García-Hernández, R., E-mail: rgarcia@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); Dzib-Pérez, L., E-mail: luirdzib@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); García-Ochoa, E.M., E-mail: emgarcia@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); González-Sánchez, J., E-mail: jagonzal@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico)

    2014-12-01

    Highlights: • Electromagnetic interaction in welding improved localised corrosion resistance. • Electromagnetic interaction in welding enhanced γ/δ phase balance of DuplexSS. • Welding under Electromagnetic interaction repress formation and growth of detrimental phases. • Welds made with gas protection (2% O{sub 2} + 98% Ar) have better microstructural evolution during welding. - Abstract: The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O{sub 2} (M1) and 97% Ar + 3% N{sub 2} (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  16. Microstructural Characterization and Wear Behavior of Nano-Boride Dispersed Coating on AISI 304 Stainless Steel by Hybrid High Velocity Oxy-Fuel Spraying Laser Surface Melting

    Science.gov (United States)

    Sharma, Prashant; Majumdar, Jyotsna Dutta

    2015-07-01

    The current study concerns the detailed microstructural characterization and investigation of wear behavior of nano-boride dispersed coating developed on AISI 304 stainless steel by high velocity oxy-fuel spray deposition of nickel-based alloy and subsequent laser melting. There is a significant refinement and homogenization of microstructure with improvement in microhardness due to laser surface melting (1200 VHN as compared to 945 VHN of as-sprayed and 250 VHN of as-received substrate). The high temperature phase stability of the as-coated and laser melted surface has been studied by differential scanning calorimeter followed by detailed phase analysis at room and elevated temperature. There is a significant improvement in wear resistance of laser melted surface as compared to as-sprayed and the as-received one due to increased hardness and reduced coefficient of friction. The mechanism of wear has been investigated in details. Corrosion resistance of the coating in a 3.56 wt pct NaCl solution is significantly improved (4.43 E-2 mm/year as compared to 5 E-1 mm/year of as-sprayed and 1.66 mm/year of as-received substrate) due to laser surface melting as compared to as-sprayed surface.

  17. Effect of Welding Current and Time on the Microstructure, Mechanical Characterizations, and Fracture Studies of Resistance Spot Welding Joints of AISI 316L Austenitic Stainless Steel

    Science.gov (United States)

    Kianersi, Danial; Mostafaei, Amir; Mohammadi, Javad

    2014-09-01

    This article aims at investigating the effect of welding parameters, namely, welding current and welding time, on resistance spot welding (RSW) of the AISI 316L austenitic stainless steel sheets. The influence of welding current and welding time on the weld properties including the weld nugget diameter or fusion zone, tensile-shear load-bearing capacity of welded materials, failure modes, energy absorption, and microstructure of welded nuggets was precisely considered. Microstructural studies and mechanical properties showed that the region between interfacial to pullout mode transition and expulsion limit is defined as the optimum welding condition. Electron microscopic studies indicated different types of delta ferrite in welded nuggets including skeletal, acicular, and lathy delta ferrite morphologies as a result of nonequilibrium phases, which can be attributed to a fast cooling rate in the RSW process. These morphologies were explained based on Shaeffler, WRC-1992, and pseudo-binary phase diagrams. The optimum microstructure and mechanical properties were achieved with 8-kA welding current and 4-cycle welding time in which maximum tensile-shear load-bearing capacity or peak load of the welded materials was obtained at 8070 N, and the failure mode took place as button pullout with tearing from the base metal. Finally, fracture surface studies indicated that elongated dimples appeared on the surface as a result of ductile fracture in the sample welded in the optimum welding condition.

  18. Impact of the surface roughness of AISI 316L stainless steel on biofilm adhesion in a seawater-cooled tubular heat exchanger-condenser.

    Science.gov (United States)

    García, Sergio; Trueba, Alfredo; Vega, Luis M; Madariaga, Ernesto

    2016-11-01

    The present study evaluated biofilm growth in AISI 316L stainless steel tubes for seawater-cooled exchanger-condensers that had four different arithmetic mean surface roughness values ranging from 0.14 μm to 1.2 μm. The results of fluid frictional resistance and heat transfer resistance regarding biofilm formation in the roughest surface showed increases of 28.2% and 19.1% respectively, compared with the smoothest surface. The biofilm thickness taken at the end of the experiment showed variations of up to 74% between the smoothest and roughest surfaces. The thermal efficiency of the heat transfer process in the tube with the roughest surface was 17.4% greater than that in the tube with the smoothest surface. The results suggest that the finish of the inner surfaces of the tubes in heat exchanger-condensers is critical for improving energy efficiency and avoiding biofilm adhesion. This may be utilised to reduce biofilm adhesion and growth in the design of heat exchanger-condensers.

  19. IN SITU OBSERVATION OF GROWTH BEHAVIOR AND MORPHOLOGY OF DELTA-FERRITE AS FUNCTION OF SOLIDIFICATION RATE IN AN AISI304 STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    G.F. Liang; C.Q. Wan; J.C. Wu; G.M. Zhu; Y. Yu; Y. Fang

    2006-01-01

    It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using confocal scanning laser microscopy ( CSLM). The δ-phase always appears like cells on the sample surface when critical supercooling occurs, during which the L→δtransformation starts. The solid-liquid (S-L) interface is found to be finger shaped and has no faceted shape. Γ phase appears among δ grains due to partitioning of Ni into the melt during solidification, when solidification rate is higher. The mergence of observed δ cells is possible for the steel sample cooled at 7.5℃/min. The formation of dendrites can be observed on the free surface of the steel sample cooled at 150℃/min. The size of solidified delta grains decreases from 120 to 20-80μm, and the volume fraction of solidified austenite increases with increase in solidification rate from 7.5 to 150℃/min. The relation between the tip radius of δ cell and its growth rate is deduced, and the results agree with the experimental values.

  20. Estimation of Fatigue Life of Laser Welded AISI304 Stainless Steel T-Joint Based on Experiments and Recommendations in Design Codes

    DEFF Research Database (Denmark)

    Lambertsen, Søren Heide; Damkilde, Lars; Kristensen, Anders Schmidt;

    2013-01-01

    In this paper the fatigue behavior of laser welded T-joints of stainless steel AISI304 is investigated experimentally. In the fatigue experiments 36 specimens with a sheet thickness of 1 mm are exposed to one-dimensional cyclic loading. Three different types of specimens are adopted. Three groups....... The non-welded specimens are used to study the influence of heat and surface effects on the fatigue life. The fatigue life from the experiments is compared to fatigue life calculated from the guidelines in the standards DNV-RP-C203 and EUROCODE 3 EN-1993-1-9. Insignificant differences in fatigue life...... of the welded and non-welded specimens are observed in the experiments and the largest difference is found in the High Cycle Fatigue (HCF) area. The specimens show a lower fatigue life compared to DNV-RP-C203 and EUROCODE 3 EN-1993-1-9 when the spe-cimens are exposed to less than 4.0 1E06 cycles. Therefore, we...

  1. Laser-assisted direct joining of AISI304 stainless steel with polycarbonate sheets: Thermal analysis, mechanical characterization, and bonds morphology

    Science.gov (United States)

    Lambiase, F.; Genna, S.

    2017-02-01

    Laser-Assisted Metal and Plastic bonding (LAMP) of AISI304 sheets with polycarbonate sheets is investigated in this work. The process was performed by means of a high power diode laser with a maximum power of 200 W. The study introduces an integrated experimental approach aimed at understanding how the main process conditions (laser power and scanning speed) influence the direct-bonds quality, dimensions and presence of defects. To this end, the bonds dimension, shear strength, formation and dimension of bubbles in the bonded region were related to the temperature measurements and process parameters. According to the achieved results, the processing window that enables a good adhesion of the two materials is relatively small; this is due the activation of the adhesion phenomena that require overcoming an energy threshold. However, excessive energy levels reduce the bonds strength due to the increase in defects (bubbles) dimension that may combine (coalescence) leading to the formation of a central tunnel where the two substrates are completely detached.

  2. The effect of CO2 laser beam welded AISI 316L austenitic stainless steel on the viability of fibroblast cells, in vitro.

    Science.gov (United States)

    Köse, Ceyhun; Kaçar, Ramazan; Zorba, Aslı Pınar; Bağırova, Melahat; Allahverdiyev, Adil M

    2016-03-01

    It has been determined by the literature research that there is no clinical study on the in vivo and in vitro interaction of the cells with the laser beam welded joints of AISI 316L biomaterial. It is used as a prosthesis and implant material and that has adequate mechanical properties and corrosion resistance characteristics. Therefore, the interaction of the CO2 laser beam welded samples and samples of the base metal of AISI 316L austenitic stainless steel with L929 fibroblast cells as an element of connective tissue under in vitro conditions has been studied. To study the effect of the base metal and the laser welded test specimens on the viability of the fibroblast cells that act as an element of connective tissues in the body, they were kept in DMEMF-12 medium for 7, 14, 28 days and 18 months. The viability study was experimentally studied using the MTT method for 7, 14, 28 days. In addition, the direct interaction of the fibroblast cells seeded on 6 different plates with the samples was examined with an inverted microscope. The MTT cell viability experiment was repeated on the cells that were in contact with the samples. The statistical relationship was analyzed using a Tukey test for the variance with the GraphPad statistics software. The data regarding metallic ion release were identified with the ICP-MS method after the laser welded and main material samples were kept in cell culture medium for 18 months. The cell viability of the laser welded sample has been detected to be higher than that of the base metal and the control based on 7th day data. However, the laser welded sample's viability of the fibroblast cells has diminished by time during the test period of 14 and 28 days and base metal shows better viability when compared to the laser welded samples. On the other hand, the base metal and the laser welded sample show better cell viability effect when compared to the control group. According to the ICP-MS results of the main material and laser welded

  3. Oxidation behavior of 26Cr-16Ni and AISI 309 austenitic stainless steels in air flow at 1,173 K

    Energy Technology Data Exchange (ETDEWEB)

    Pipatnukun, Peeraya; Wangyao, Panyawat; Lothongkum, Gobboon [Chulalongkorn Univ., Bangkok (Thailand). Dept. of Metallurgical Engineering

    2015-11-01

    This work investigates the isothermal oxidation behavior of as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 at 1,173 K in air flow rate of 40 cm{sup 3} x min{sup -1} using thermogravimetric analysis (TGA). In 33 hours, the oxidation resistance declines from high to low are as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309, respectively. The oxidation kinetic results show that the exponential rate constant of the as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 are 8.79 x 10{sup -6}, 4.02 x 10{sup -5} and 4.35 x 10{sup -5} g x cm{sup -2} x s{sup -n}, respectively. The exponential growth rates of as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 are 0.42, 0.29 and 0.32, respectively. It indicates that the oxidation kinetic of as cast 26Cr-16Ni approaches a parabolic rate law, but those of as cold-rolled and as cast AISI 309 approach the cubic rate law. The sequence of oxide scale formations on the tested samples is also discussed.

  4. 表面自纳米化304L不锈钢/T2铜扩散连接%Diffusion bonding of SSNC 304L/Cu

    Institute of Scientific and Technical Information of China (English)

    罗军; 盛光敏; 袁新建

    2013-01-01

    A 304L austenitic stainless steel, surface self-nanocrystallized (SSNC) by high-energy shot peening (HESP), was studied by optical microscope and micro hardness tester. Original and SSNC 304L austenitic stainless steels were separately joined with copper through pulse-pressure diffusion bonding (PPDB) at 850 ℃ for 600 s. The joint strength was tested by a tensile machine, the longitudinal sections and tensile fractures of joints were analyzed by scanning electron microscope (SEM) and energy dispersive spectroscope (EDS). Additionally, the diffusion coefficient of Cu atom in 304L austenitic stainless steel was achieved. The results show that a severe plastic deformation layer, about 60 μm, was obtained after HESP. The average recorded tensile strength of SSNC 304L /Cu joints is equal to 228.2 MPa, which is 83% of that of Cu bar, 20% more than that of the original 304L/Cu. The diffusion coefficient of Cu atom in SSNC 304L is 8.5 × 10-14 m2/s, five times higher than that in original 304L.%采用高能喷丸(HESP)对304L不锈钢棒端面进行表面自纳米化(SSNC)处理,在850℃下将不锈钢与铜棒进行600 s脉冲加压扩散连接(PPDB).利用金相显微镜和显微硬度仪对不锈钢棒喷丸端面进行表征,测试接头拉伸强度,对断口和接头剖面进行SEM和EDS分析,并计算Cu原子在不锈钢中的扩散系数.实验结果表明:经SSNC处理在不锈钢表层获得大约60 μm的剧烈塑性变形层.铜与经SSNC处理的不锈钢的接头平均抗拉强度达到228.2MPa,达到铜基体的83%,比铜与未经SSNC处理的不锈钢的接头的抗拉强度提高20%;铜原子在经SSNC处理的不锈钢中的扩散系数达到8.5×10-14 m2/s,比在未经SSNC处理的不锈钢中高5倍.

  5. Cross-sectional transmission electron microscopy of ultra-fine wires of AISI 316L stainless steel

    Science.gov (United States)

    Wang, H. S.; Wei, R. C.; Huang, C. Y.; Yang, J. R.

    2006-01-01

    Starting with 190?µm diameter wire of 316L stainless steel, ultra-thin wire just 8?µm in diameter has been made and characterized. There was no intermediate heat treatment used in the process of drawing, and the amount of true stain was about 6.3. A specimen preparation method for the cross-sectional transmission electron microscopy (TEM) of ultra-fine wires of 316L stainless steel has been developed. The ultra-fine wire was sandwiched between silicon chips and the bonded assembly then sliced to produce longitudinal and transverse sections of the wire in a form suitable for further processing into electron transparent samples. TEM reveals that the heavily deformed wire consists of nanoscale fine elongated structures along the drawing direction. The diffraction patterns indicate that a substantial amount of austenite has transformed into martensite. The TEM dark field images show nanosized patches of martensite distributed among the debris of austenite along the drawing direction. The evidence strongly suggests that severe deformation leads to mechanical stabilization of austenite against the growth of martensite.

  6. Passivity of AISI 321 stainless steel in 0.5 M H2SO4 solution studied by Mott–Schottky analysis in conjunction with the point defect model

    Directory of Open Access Journals (Sweden)

    A. Fattah-alhosseini

    2016-11-01

    Full Text Available The passivity of AISI 321 stainless steel in 0.5 M H2SO4 solution, in the steady-state condition, has been explored using electrochemical impedance spectroscopy (EIS and Mott–Schottky analysis. Based on the Mott–Schottky analysis in conjunction with the point defect model (PDM, it was shown that the calculated donor density decreases exponentially with increasing passive film formation potential. The thickness of the passive film was increased linearly with the formation potential. These observations were consistent with the predictions of the PDM, noting that the point defects within the passive film are metal interstitials, oxygen vacancies, or both.

  7. Articles comprising ferritic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Rakowski, James M.

    2016-06-28

    An article of manufacture comprises a ferritic stainless steel that includes a near-surface region depleted of silicon relative to a remainder of the ferritic stainless steel. The article has a reduced tendency to form an electrically resistive silica layer including silicon derived from the steel when the article is subjected to high temperature oxidizing conditions. The ferritic stainless steel is selected from the group comprising AISI Type 430 stainless steel, AISI Type 439 stainless steel, AISI Type 441 stainless steel, AISI Type 444 stainless steel, and E-BRITE.RTM. alloy, also known as UNS 44627 stainless steel. In certain embodiments, the article of manufacture is a fuel cell interconnect for a solid oxide fuel cell.

  8. Internal Friction on AISI 304 Stainless Steels with Low Tensile Deformations at Temperatures between −50 and 20C

    Directory of Open Access Journals (Sweden)

    T. F. A. Santos

    2010-01-01

    Full Text Available Austenitic stainless steels specimens were deformed by tension in temperatures in the range of −50C to 20 C and 0.03 to 0.12 true strain, in order to obtain different volumetric fractions of ε (hexagonal close packed and α′ (body centered cubic strain induced martensites. The morphology, distribution and volumetric fractions of the martensites were characterized by metallography and dilatometry analysis and quantified by ferrite detector measurements. The damping behavior of specimens with different volumetric fractions of martensites was studied in an inverted torsion pendulum in the 40C to 400C range. The ε- and α′-martensites reversion was observed in the temperature range of 50C–200C and 500C–800C, respectively, by dilatometry. Internal friction curves in function of temperature of the deformed samples presented internal friction peaks. The first internal friction peak is related to sum of the amount of ε- and α′-martensites. For low deformations it aligns around 130C and it is related only to the ε→γ reverse transformation. The peak situated around 350C increases with the specimen degree of deformation and is, probably, related to the presence of α′/γ interfaces, and deformed austenite.

  9. Understanding the effect of uniaxial tensile strain on the early stages of sensitization in AISI 304 austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, P.S., E-mail: psc0126@gmail.com [Techno India Agartala, Maheshkhola, Agartala, West Tripura PIN – 799004 (India); Guchhait, S.K.; Mitra, P.K. [Department of Metallurgical and Material Engineering, Jadavpur University, Kolkata 700032 (India); Mukherjee, P.; Gayathri, N. [Variable Energy Cyclotron Centre (VECC), 1/AF Bidhan Nagar, Kolkata 700064 (India); Mitra, M.K. [Department of Metallurgical and Material Engineering, Jadavpur University, Kolkata 700032 (India)

    2015-04-01

    In the present study, an attempt has been made to understand the effect of different competing mechanisms controlling the overall degree of sensitization (DOS) of deformed austenitic stainless steel at the early stage of sensitization. The Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) studies were performed to characterize the Degree of Sensitization (DOS) as a function of both pre-defined strain and sensitization temperature. X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were used to explain the phenomena qualitatively. A non monotonous behaviour in the variation of DOS has been observed with deformation and sensitization temperature. The presence of Deformation Induced Martensites (DIM) and their transformation into tempered martensites (α + M{sub 23}C{sub 6}) at higher temperatures was found to play major roles in controlling the overall sensitization and desensitization processes. - Highlights: • Interplay of various dynamic processes (four) in the early sensitization. • Deformation induced martensite (α′) playing major role at low temperature. • α (Tempered martensite) induced processes plays a vital role at higher temperatures. • Results in non monotonous variation in degree of sensitisation (DOS)

  10. Effect of ferric ions in AISI 316L stainless steel pickling using an environmentally-friendly H{sub 2}SO{sub 4}-HF-H{sub 2}O{sub 2} mixture

    Energy Technology Data Exchange (ETDEWEB)

    Narvaez, L. [Metallurgical Institute, UASLP Avda. Sierra Leona 550, 78210 San Luis Potosi (Mexico); Cano, E.; Bastidas, J.M. [CENIM-National Centre for Metallurgical Research (CSIC) Avda. Gregorio del Amo 8, 28040 Madrid (Spain)

    2003-02-01

    A mixture of hydrogen peroxide, sulphuric and hydrofluoric acids has been used as pickling solution at pH 2.0 for AISI 316L austenitic stainless steel (SS). The stability of the H{sub 2}SO{sub 4}-HF-H{sub 2}O{sub 2} mixture is assessed varying the ferric ions content from 0 to 40 g/L, the temperature from 25 to 60 C, and with and without stirring of the pickling solution. The AISI 316L SS pickling rate at 50 C was 2.6 and 0.2 mg/dm{sup 2} day (mdd) in the absence and presence of 40 g/L ferric ions, respectively. p-toluene sulphonic acid (PTSA) has been used as stabiliser of hydrogen peroxide. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Es ist ein Gemisch mit einem pH-Wert von 2.0 aus Wasserstoffperoxid, Schwefelsaeure und Fluorwasserstoffsaeure als Beizloesung fuer nichtrostenden Stahl AISI 316L angewandt worden. Die Stabilitaet des Gemisches H{sub 2}SO{sub 4}-HF-H{sub 2}O{sub 2} haengt vom Gehalt der dreiwertigen Eisenionen, zwischen 0 und 40 g/L, von der Temperatur, zwischen 25 und 60 C, und von der Ruehrintensitaet der Beizloesung ab. Die Beizgeschwindigkeit des nichtrostenden Stahls AISI 316L bei 50 C lag bei 2.6 bzw. 0.2 mg/dm{sup 2} taeglich (mdd), je nachdem, ob 40 g/L dreiwertige Eisenionen enthalten waren oder nicht. Als Stabilisator des Wasserstoffperoxids ist para-Toluensulfonsaeure (PTSA) eingesetzt worden. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  11. Analysis of the fatigue strength under two load levels of a stainless steel based on energy dissipation

    Directory of Open Access Journals (Sweden)

    Ricotta M.

    2010-06-01

    Full Text Available In this paper the fatigue behaviour of a stainless steel AISI 304L is analysed. In the first part of the work the results obtained under constant amplitude fatigue are presented and synthesised in terms of both stress amplitude and energy released to the surroundings as heat by a unit volume of material per cycle, Q. Then some specimens have been fatigued in variable amplitude, two different load level tests: the first level was set higher while the second was lower than the constant amplitude fatigue limit. The Q values, evaluated during the second part of the fatigue test, have been compared with those calculated under constant amplitude fatigue at the same load level. The comparison allowed us to notice that the Q parameter is sensitive to the fatigue damage accumulated by the material during the first part of the fatigue test.

  12. Analysis of the fatigue strength under two load levels of a stainless steel based on energy dissipation

    Directory of Open Access Journals (Sweden)

    M. Ricotta

    2011-07-01

    Full Text Available In this paper the fatigue behaviour of a stainless steel AISI 304L is analysed. In the first part of the work the results obtained under constant amplitude fatigue are presented and synthesised in terms of both stress amplitude and energy released to the surroundings as heat by a unit volume of material per cycle, Q. Then some specimens have been fatigued in variable amplitude, two different load level tests: the first level was set higher while the second was lower than the constant amplitude fatigue limit. The Q values, evaluated during the second part of the fatigue test, have been compared with those calculated under constant amplitude fatigue at the same load level. The comparison allowed us to notice that the Q parameter is sensitive to the fatigue damage accumulated by the material during the first part of the fatigue test.

  13. Role of Microstructural Constituents on Surface Crack Formation During Hot Rolling of Standard and Low Nickel Austenitic Stainless Steels

    Institute of Scientific and Technical Information of China (English)

    Manidipto Mukherjee; Tapan Kumar Pal

    2013-01-01

    The effect of alloy segregation and delta (δ) ferrite contents on surface cracking of three standard (i.e.AISI 304L,AISI 310S and AISI 321) and two low nickel (i.e.LNi-1 and LNi-0.3) austenitic stainless steels (ASS)during hot rolling was investigated using optical microscopy (OM),automatic image analyzer,scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDX) and electron probe micro analyzer (EPMA).It was observed that the amount of δ-ferrite varied among different grades and also distributed heterogeneously across the width of the steel plates.In general,low nickel ASS showed higher amount of δ-ferrite compared to the standard ASS grades.The tendency to surface cracking during hot rolling gradually increased with increasing δ-ferrite content.Interestingly,carbon and nitrogen exerted maximum effect on δ-ferrite formation.The higher carbon and nitrogen content in the steel decreased δ-ferrite content.In addition,the segregation of Cu and Mn plays significant role in low nickel ASS and Ni-Cr in case of standard ASS has profound effect on surface cracking of the steel plates.A possible cause of surface crack formation/origination in steel plates during hot rolling was discussed.

  14. Comparison of the fatigue behavior and residual stress stability of laser-shock peened and deep rolled austenitic stainless steel AISI 304 in the temperature range 25-600 deg. C

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, I. [Institute of Materials Engineering, University of Kassel (Germany)], E-mail: nikitin@uni-kassel.de; Altenberger, I. [Institute of Materials Engineering, University of Kassel (Germany)

    2007-09-15

    Laser-shock peening and deep rolling were applied to an austenitic stainless steel AISI 304 and the effects on the fatigue life were investigated. Isothermal push-pull fatigue tests were performed in the temperature range 25-600 deg. C. The results of the investigations, e.g. s/n curves, cyclic deformation curves as well as the residual stress stability of the laser-shock peened condition were compared to untreated and deep rolled conditions. Near-surface regions were characterized using X-ray diffraction methods, transmission electron microscopy (TEM) and focused ion beam microscopy (FIB). The different near-surface microstructures as well as residual stress stabilities of laser-shock peened and deep rolled specimens were investigated and discussed.

  15. Corrosion Resistance of 304L SS Spray Coated with Zirconia Nanoparticles

    Science.gov (United States)

    Maheswari, A. Uma; Sivakumar, M.; Indhumathi, N.; Mohan, Sreedevi R.

    2016-09-01

    Influence of substrate temperature on corrosion (in 3.5% NaCl) and wear resistance of nanostructured zirconia thin film coated 304L SS substrates are studied by electrochemical and nano-indentation methods. This analysis shows 304L SS substrate spray coated with nanostructured zirconia at substrate temperature closer to the boiling point of the spray solvent ethanol exhibited good corrosion and wear resistance behaviour. This is because of the compressive stress developed during film fabrication at lower substrate temperature (∼50 °C) and hence constrains the indentation plasticity, which leads to higher indentation load than the bare 304L SS.

  16. Controlled dissolution of colossal quantities of nitrogen in stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2006-01-01

    The solubility of nitrogen in austenitic stainless steel was investigated thermogravimetrically by equilibrating thin foils of AISI 304 and AISI 316 in ammonia/hydrogen gas mixtures. Controlled dissolution of colossal amounts of nitrogen under metastable equilibrium conditions was realized...

  17. The effect of nitrogen in sintered atmosphere of the ferritic stainless steels AISI 430L P/M; Efecto del nitrogeno en la atmosfera de sinterizacion del acero inoxiable ferritico AISI 430L P/M

    Energy Technology Data Exchange (ETDEWEB)

    Corpas, F. A.; Ruiz-Roman, J. M.; Codina, S.; Iglesias, F. J.

    2005-07-01

    In this paper, we have studied the nitrogen effects different sintering atmospheres (nitrogen-hydrogen, and dissociate ammonia) on ferritic stainless steels (430L), fabricated by powder metallurgy process. We have carried out a study of the physical (density, porosity and dimensional variation) and mechanical properties (hardness, tensile strength, and lengthening) of the ferritic stainless steels sintered in the afore-mentioned atmospheres, as well as of their behaviour in pitting corrosion. We have studied, also the microstructure of the steels, which depends on the atmosphere used for sintering. (Author) 13 refs.

  18. Behavior to the fracture of an AISI 304 stainless steel sensitized in BWR reactor conditions (288 degrees Centigrade and 80 Kg/cm{sup 2}); Comportamiento a la fractura de un acero inoxidable AISI 304 sensibilizado en condiciones de reactor BWR (288 grados Centigrados y 80 Kg/cm{sup 2})

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez C, R.; Diaz S, A.; Garcia R, R.; Aguilar T, A.; Gachuz M, M.; Arganis J, C.; Merino C, J. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    It is a knew fact that ductility of a lot of structural alloys can be deteriorated by the environment effect which are exposed, and that their consequent embrittlement can put in doubt the safety of their functioning; such is the case of austenitic stainless steels used in internal components of the BWR type reactors which not only is subjected to the effect combined of the aggressive environment which surround it (pressure, temperature, corrosion potential, conductivity medium, local state of efforts, etc.), but also to the action of present neutron radiation, manifesting microstructural changes which are reflected in the augmentation of its susceptibility to the intergranular cracking, phenomena generally known as IASCC ''Irradiation Assisted Stress Corrosion Cracking''. Once appeared the cracking in the material, the useful life of a component is limited by the rapidity to growth of these cracking, making necessary evaluations which can to predict its behavior, therefore the present work shows the preliminary results for determining the behavior to the fracture of an AISI 304 stainless steel sensitized, in a dynamic recirculation circuit which allows to simulate the operation conditions of a BWR reactor (288 Centigrade and 80 kg/cm{sup 2}). (Author)

  19. Microbiologically influenced corrosion evaluation on brass (UNS C68700, UNS C443) and AISI 316 stainless steel; Estudio de la influencia microbiologica en la corrosion de latones (UNS C68700, UNS C443) y acero inoxidable AISI 316

    Energy Technology Data Exchange (ETDEWEB)

    Ohanian, M.; Diaz, V.; Corengia, M.; Russi, P.; Pianzzola, M. J.; Menes, R. J.

    2014-10-01

    Microorganisms may play an important role in the corrosion process and generate conditions which affect the rate and/or the mechanism of deterioration. They become visible by the formation of bio films: clusters of microorganisms and extracellular polymers. These bio films affect not only the durability of the material, but also reduce the heat transfer. The present work studied the growth of aerobic and anaerobic heterotrophic microorganisms and sulfate reducing bacteria on aluminum brass (Uns C.a.), admiralty brass (Uns C.a.) and stainless steel Asi 316 in exposure experiments held in the Bay of Montevideo (Uruguay). The influence of the biofilm growth on the corrosion behavior was studied by electrochemical techniques: polarization curves and Electrochemical Impedance Spectroscopy (Ei). The selection of the most suitable material for the exposure conditions is discussed and hypotheses of the corrosion mechanism are presented. Although stainless steel Asi 316 presented the lowest corrosion rate it showed localized deterioration. (Author)

  20. Characterization of gold and nickel coating on AISI 304 stainless steel for use in the fabrication of current collector plates for fuel cells; Caracterizacion de recubrimientos de oro y niquel realizados sobre acero inoxidable AISI 304 para su empleo en la fabricacion de placas colectoras de corriente para celdas de combustible

    Energy Technology Data Exchange (ETDEWEB)

    Flores Hernandez, J. Roberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)] e-mail: jrflores@iie.org.mx; Aguilar Gama, M. Tulio [UNAM. Facultad de Quimica, Mexico D.F. (Mexico); Cano Castillo, Ulises; Albarran, Lorena [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Olvera, J. Carlos; Orozco, German [CIDETEQ, Pedro Escobedo, Queretaro (Mexico)

    2009-09-15

    Among the different components that compose fuel cell technology (MEA, bipolar plates, seals, etc.) current collector plates play an important role in the good performance of fuel cells, since they collect all of the current generated and distribute it to the external circuit. Therefore, the most important properties that the current collector plates should have are excellent conductivity and good resistance to the corrosive conditions present in the fuel cell. This document presents results obtained during the nickel and gold electrodeposition process on AISI 304 stainless steel and the morphology and thickness of each coating, their adhesion, hardness and conductivity values. Finally, results obtained during some of the electrochemical tests performed on the coatings are shown. [Spanish] De los diferentes componentes que integran la tecnologia de celdas de combustible (MEA's, placas bipolares, sellos, etc.), las placas colectoras de corriente tienen un importante rol en el buen desempeno de la celdas de combustibles, ya que en estas placas se colecta toda la corriente generada y se distribuye al circuito externo. Debido a esto, las propiedades mas importantes que deben tener las placas colectaras de corriente son: excelente conductividad y buena resistencia a las condiciones corrosivas presentes en la celda de combustible. En este documento se presentan los resultados obtenidos en el proceso de electrodeposicion de niquel y oro sobre acero inoxidable AISI 304, asi como la morfologia y el espesor de cada recubrimiento, sus valores de adherencia, dureza y conductividad. Finalmente se muestran tambien los resultados obtenidos de algunas pruebas electroquimicas a los que fueron sometidos los recubrimientos.

  1. Estudo do comportamento eletroquímico de azóis para o aço inoxidável AISI 430 em H2SO4 1 mol L-1 Study of electrochemical behavior of azoles for AISI 430 stainless steel in H2SO4 1 mol L-1

    Directory of Open Access Journals (Sweden)

    Martha Tussolini

    2010-03-01

    Full Text Available A corrosão é um processo indesejável que ocorre em materiais metálicos. Nesse trabalho, estudou-se o efeito inibidor do benzotriazol (BTAH, benzimidazol (BZM e indol em diferentes concentrações para o aço inoxidável AISI 430 em H2SO4 1 mol L-1. Foram empregadas as técnicas de: polarização potenciostática anódica, espectroscopia de impedância eletroquímica, microscopia óptica e eletrônica de varredura. As curvas de polarização potenciostática anódica mostraram que o BTAH, BZM e Indol atuam como inibidores de corrosão para o aço AISI 430, nas concentrações de 1x10-3 e 5x10-4 mol L-1, não apresentando inibição significativa para as concentrações iguais ou inferiores a 1x10-4 mol L-1. O aumento da eficiência inibidora em relação às substâncias estudadas seguiu a seguinte ordem: Indol Corrosion is an undesirable process that occurs in metallic materials. Studied was the effect of inhibiting Benzotriazole (BTAH, Benzimidazole (BZM and Indole in different concentrations for the stainless steel (SS AISI 430 in H2SO4 1 mol L-1. The techniques employed this research were: anodic potenciostatic polarisation, electrochemical impedance spectroscopy, optical microscopy and scanning electron microscopy. The curves of anodic polarisation showed that BTAH, BZM and Indol act as corrosion inhibitors for 430 SS, at concentrations of 1x10-3 and 5x10-4 mol L-1, but do not inhibit corrosion for concentrations equal to or less than 1x10-4 mol L-1. The in-crease of the efficiency in relation to the inhibitory substances studied followed this order: Indol

  2. Friction and wear of selected metals and alloys in sliding contact with AISI 440 C stainless steel in liquid methane and in liquid natural gas

    Science.gov (United States)

    Wisander, D. W.

    1978-01-01

    Aluminum, titanium, beryllium, nickel, iron, copper, and several copper alloys were run in sliding contact with AISI 440C in liquid methane and natural gas. All of the metals run except copper and the copper alloys of tin and tin-lead showed severely galled wear scars. Friction coefficients varied from 0.2 to 1.0, the lowest being for copper, copper-17 wt. % tin, and copper-8 wt. % tin-22 wt. % lead. The wear rate for copper was two orders of magnitude lower than that of the other metals run. An additional order of magnitude of wear reduction was achieved by the addition of tin and/or lead to copper.

  3. Influence of Water Pollution on MIC of Stainless Steel 304L

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of water pollution and welding defects on MIC (microbiologically influenced corrosion) was studied. The open circuit potential (OCP) was measured during MIC test. It was found that OCP shifted to a higher level when the system was inoculated with bacteria while the OCP of those samples in water without bacteria was kept at a low level. The OCP decreased dramatically when MIC started in polluted water. Combination of weld defect-heat tint, polluted water and adding bacteria causes MIC happen at high rate. Some elements inside the tubercle were analyzed with EDXA. The pits and biofilm were observed with SEM. Microbiological analysis revealed the difference of bacteria between corroded and uncorroded samples.

  4. Deformability analysis of the AISI 304 DDQ stainless steel under deep drawing multiaxial condition. Evaluation of the initial strain influence; Analisis de la deformabilidad del acero inoxidable AISI 304 DDQ en condiciones multiaxiales de embuticion. Evaluacion de la influencia de la acritud inicial

    Energy Technology Data Exchange (ETDEWEB)

    Coello, J.; Miguel, V.; Calatayud, A.; Martinez, A.; Ferrer, C.

    2010-07-01

    The deep drawing formability of a material is established as a function of standard indexes, as strength coefficient and anisotropy coefficient. But these indexes are determined in different conditions to those that take place in the forming process. The simulative assays do not separate the actions due to the different variables that work in the process, as for example, the rolling direction. In the present work a test that uses a wedge shape die is considered in order to obtain the strength and anisotropy coefficients as a function of rolling direction. This way, the assays are carried out under a tensile-biaxial compression stress state similar to that one taking place in the flange zone in deep drawing. The experimented material is a deep drawing quality stainless steel AISI 304. The influence of initial strengthened states, rolling and uniaxial tensile on the steel behaviour are also studied. The results permits the authors establish the validity of the assay from the point of view of the strains produced in the sheet. The initial strain has a higher effect on the material than that one obtained from the tensile-biaxial of the state than the tensile-biaxial compression causes. The anisotropy coefficient changes with the strain for the sheet rolling direction. (Author).

  5. Spring back evaluation by bending under tension tests in conditions of multiaxial stresses corresponding to deep drawing processes. Application to AISI 304 DDQ stainless steel sheet; Evaluacion del springback mediante ensayos de doblado bajo tension en condiciones de multiaxialidad tipicas de los procesos de embuticion profunda. Aplicacion a chapa de acero inoxidable AISI 304 DDQ

    Energy Technology Data Exchange (ETDEWEB)

    Miguel, V.; Coello, J.; Martinez, A.; Calatayud, A.

    2013-09-01

    In this paper, a methodology has been developed for evaluating the spring back of AISI 304 DDQ stainless steel sheet based on a bending under tension test. The main difference of the methodology herein carried out is that tests are made under the multiaxial stresses state that take place in deep drawing processes. This affects to the level of stress value in the test and to the hardening state of the sheet. Springback evaluation has been done in two different areas. Bending area has been evaluated from elastic recovery ratio defined as the ratio between the bending radius after and before bending. Bending and unbending extreme has been studied from the measured curvature radius in this area and taking into account the geometric equivalence of the test with the drawing cups process. Results found allow to state that drawing ratio or deformation ratio have a negligible influence on the springback into the range of values experimented here. Bending radius has hardly influence as well while bending angle is the most significant variable. The results obtained are compared to those measured in deep-drawn cups, finding a great agreement. (Author)

  6. Characterization by EBSD technique of AISI 304 DDQ stainless steel sheet deformed under typical deep drawing multiaxial stress system; Caracterizacion mediante la tecnica EBSD de la defromacion de chapa de acero inoxidable AISI 304 DDQ bajo tensiones multiaxiales tipicas de la embuticion

    Energy Technology Data Exchange (ETDEWEB)

    Coello, J.; Miguel, V.; Calatayud, A.; Ferrer, C.; Martinez, A.

    2009-07-01

    The main aim of this work to evaluate AISI 304 DDQ stainless steel behaviour under deep drawing deformation condition, that is pure shear deformation in which materials suffers a typical deformation under tension-biaxial compression stresses system. The microstructural evolution has been investigated by optical microscopy and by EBSD technique. The success of the EBSD analysis has been established for the deformation conditions experimented here. It has been determined the rolling direction and the equivalent strain influence on the crystallographic orientation maps, misorientation diagrams and poles figures. The results let the authors say the low angle misorientation corresponding to 0,45 and 90 degree centigrade rolling directions have an inverse correlation with the material anisotropy. Initial pre-straining has been considered also and the analysis of this aspects lead to establish that the increment of the intragranular misorientation with the strain depends on the initial state a of the steel; this increment is observed to be minor for samples with initial prestraining. High angle misorientation analysis (>15 degree centigrade) indicates that the grain boundaries character distributions depends on the deformation. (Author) 20 refs.

  7. Fatigue life of AISI 316L stainless steel welded joints, obtained by GMAW; Vida a la fatiga de juntas soldadas del acero inoxidable AISI 316L obtenidas mediante el proceso GMAW

    Energy Technology Data Exchange (ETDEWEB)

    Puchi-Cabrera, E. S.; Saya-Gamboa, R. A.; Barbera-Sosa, J. G. la; Staia, M. H.; Ignoto-Cardinale, V.; Berrios-Ortiz, J. A.; Mesmacque, G.

    2007-07-01

    An investigation has been conducted in order to determine the effect of both the metallic transfer mode (pulsed arc or short circuit) and the O{sub 2} content in the Ar/O{sub 2} gas mixture, of the gas-metal arc welding process (GMAW), on the fatigue life under uniaxial conditions of welded joints of 316L stainless. it has been concluded that the mixture of the protective gases employed in the process could have an important influence on the fatigue life of the welded joints of such steel in two different ways. firstly, through the modification of the radius of curvature at the joint between the welding tow and the base metal and, secondly, through a more pronounced degree of oxidation of the alloying elements induced by a higher O{sub 2} content in the mixture. As far as the metallic transfer mode is concerned, it has been determined that the welded joints obtained under a pulsed arc mode show a greater fatigue life in comparison with the joints obtained under short circuit for both gas mixtures. (Author) 25 refs.

  8. Metal release rate from AISI 316L stainless steel and pure Fe, Cr and Ni into a synthetic biological medium--a comparison.

    Science.gov (United States)

    Herting, G; Wallinder, I Odnevall; Leygraf, C

    2008-09-01

    Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using graphite furnace atomic absorption spectroscopy, and changes in surface oxide composition by means of X-ray photoelectron spectroscopy. To emphasise that alloys and pure metals possess totally different intrinsic properties, comparative studies were performed on the pure alloying constituents: iron, nickel and chromium. Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result. As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition.

  9. Understanding and modelling of the aniso-thermal cyclic mechanical behaviour of the AISI 316LN austenitic stainless steel; Comprehension et modelisation du comportement mecanique cyclique anisotherme de l'acier austenitique AISI 316LN

    Energy Technology Data Exchange (ETDEWEB)

    Gentet, D.

    2009-11-15

    The main subject of this report consists in proposing a mechanical model of the viscoplastic behaviour of an austenitic stainless steel under isothermal and aniso-thermal low cycle fatigue loadings at high temperatures (550-900 K). In this domain, numerous phenomena linked to dynamic strain ageing (DSA) and to dipolar dislocation structure formation may appear. Isothermal and aniso-thermal low cycle fatigue tension-compression tests were performed in order to verify some aspects about the effect of temperature on the mechanical behaviour. The study of the hysteresis loops and the observation of dislocation structures carried on transmission electron microscopy establish two different DSA mechanisms during isothermal tests. The effect of temperature history is shown for for particular temperature sequences. It is demonstrated that the stress amplitude increase when the sample is submitted to cycles at 'high temperature' is linked to the second mechanism of DSA. It comes from the increase of short range interaction between dislocations (chromium segregation), but it is also the consequence of the lack of dipolar structure annihilation at low temperature. From the experimental analysis of DSA mechanisms and dipolar restoration, a macroscopic aniso-thermal model is developed using physical internal variables (densities of dislocations). The equations of a polycrystalline model are rewritten with the aim of getting a simple multi-scale approach which can be used on finite elements analysis software. Between 550 and 873 K, the simulation results are in good accordance with the macroscopic and microscopic observations of low cycle fatigue, relaxation, and 2D-ratchetting tests. (author)

  10. Effect of prior cold work on the degree of sensitisation of welded joints of AISI 316L austenitic stainless steel studied by using an electrochemical minicell

    Energy Technology Data Exchange (ETDEWEB)

    De Tiedra, Pilar [Ciencia de los Materiales e Ingenieria Metalurgica, Departamento CMeIM/EGI/ICGF/IM/IPF, Universidad de Valladolid, Escuela de Ingenierias Industriales, Paseo del Cauce 59, Valladolid 47011 (Spain); Martin, Oscar, E-mail: oml@eis.uva.es [Ciencia de los Materiales e Ingenieria Metalurgica, Departamento CMeIM/EGI/ICGF/IM/IPF, Universidad de Valladolid, Escuela de Ingenierias Industriales, Paseo del Cauce 59, Valladolid 47011 (Spain); Garcia, Cristina; Martin, Fernando; Lopez, Manuel [Ciencia de los Materiales e Ingenieria Metalurgica, Departamento CMeIM/EGI/ICGF/IM/IPF, Universidad de Valladolid, Escuela de Ingenierias Industriales, Paseo del Cauce 59, Valladolid 47011 (Spain)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Double loop shows greater sensitivity to interdendritic corrosion than single loop. Black-Right-Pointing-Pointer Fusion line sensitisation is lower than that of weld metal for all prior cold works. Black-Right-Pointing-Pointer Heat affected zone sensitisation is maximum at a prior cold work of 10%. Black-Right-Pointing-Pointer Heat affected zone sensitisation Much-Less-Than base material sensitisation for a prior cold work of 20%. - Abstract: This work aims to assess the effect of prior cold work on the degree of sensitisation of each of the four welding zones of welded joints of AISI 316L subjected to post-welding sensitisation. Electrochemical potentiokinetic reactivation and double loop electrochemical potentiokinetic reactivation tests are performed on each of the four zones by using a small-scale electrochemical cell (minicell). The results show that the degree of sensitisation of heat affected zone, which achieves its maximum at a prior cold work level of 10%, is significantly lower than that of base material for a prior cold work of 20%.

  11. Effect of Cold-Rolling on Precipitation Phenomena in Sensitized Type 316L and 340L Austenitic Stainless Steels

    Institute of Scientific and Technical Information of China (English)

    H.Tsubakino; A.Yamamoto; T. Yamada; L.Liu; M.Terasawa; S.Nakahigashi; H.Harada

    2004-01-01

    Precipitation phenomena in Type 316L and 304L stainless steels were studied mainly by transmission electron microscopic (TEM) observations after cold-rolling ranging from 0% (as solution annealed) to 80% reduction in thickness,and then by sensitization treatment. Precipitates were identified by electron diffraction analysis and EDS analysis.Precipitates observed in sensitized 316L stainless steel were sigma and chi phases, whereas carbide and sigma were observed in sensitized 304L stainless steel. Recrystallized grains were formed in 30% cold-rolled and sensitized 304L.However, the tendency toward recrystallization in sensitized 316L was much lower than in 304L. Precipitation of sigma and chi phases was accelerated by cold-rolling and they were observed at grain boundaries in lower cold-rolling; they were also seen, in grain interiors in higher cold-rolling. Higher deformation induced partially recrystallization combined with precipitation, resulting in the formation of heterogeneous microstructures.

  12. Caracterização microestrutural de soldas dissimilares dos aços ASTM A-508 e AISI 316L Characterization of dissimilar metal weld between low alloy steel ASTM A-508 and 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Luciana Iglésias Lourenço Lima

    2010-06-01

    Full Text Available As soldas dissimilares (dissimilar metal welds - DMWs são utilizadas em diversos segmentos da indústria. No caso específico de usinas nucleares, tais soldas são necessárias para conectar tubulações de aço inoxidável com componentes fabricados em aços baixa liga. Os materiais de adição mais utilizados neste tipo de solda são as ligas de níquel 82 e 182. Este trabalho consistiu na soldagem de uma junta dissimilar de aço baixa liga ASTM A-508 G3 e aço inoxidável austenítico AISI 316L utilizando as ligas de níquel 82 e 182 como metais de adição. A soldagem foi realizada manualmente empregando os processos de soldagem ao arco SMAW (Shielded Metal Arc Welding e GTAW (Gas Tungsten Arc Welding. Os corpos de prova foram caracterizados microestruturalmente utilizando-se microscópio óptico e microscópio eletrônico de varredura com microanálise por dispersão de energia de raios X (EDS e ensaios de microdureza Vickers. Observou-se uma microestrutura constituída de dendritas de austenita com a presença de precipitados com formas e dimensões definidas pelo aporte térmico e pela direção de soldagem. Não houve variação significativa da dureza ao longo da junta soldada, demonstrando a adequação dos parâmetros de soldagem utilizados.The dissimilar metal welds (DMWs are used in several areas of the industries. In the nuclear power plant, this weld using nickel alloy welding wires is used to connect stainless steel pipes to low alloy steel components on the reactor pressured vessels. The filler materials commonly used in this type of weld are nickel alloys 82 and 182.. In this study, dissimilar metal welds composed of low alloy steel ASTM A-508 G3, nickel alloys 82 e 182 as weld metals, and austenitic stainless steel AISI 316L were prepared by manual shielded metal arc welding (SMAW and gas tungsten arc welding techniques (GTAW. Samples were microstructural characterized by optical microscopy and scanning electron microscopy

  13. Effect of Ga on the Wettability of CuGa10 on 304L Steel

    Science.gov (United States)

    Silze, Frank; Wiehl, Gunther; Kaban, Ivan; Kühn, Uta; Eckert, Jürgen; Pauly, Simon

    2015-08-01

    In the present work, the effect of Ga on the wetting behavior of the Cu-rich braze filler CuGa10 (wt pct, Cu90.8Ga9.2 at. pct) on the steel 304L was investigated. For this, the macroscopic and microscopic effects governing the wetting of pure Ga, pure Cu, and CuGa10 alloy (wt pct) on the austenitic steel were analyzed and compared. Contact angle and surface tension measurements were carried out by means of the sessile drop technique, and, in addition, the phase formation at the interface was determined. Pure liquid Ga spreads on 304L, which supposedly is related to the formation of intermetallic Fe-Ga phases growing into the liquid Ga. Depending on the annealing time, FeGa3 and Fe14.5Ga12 were identified. In contrast, CuGa10 as well as pure Cu shows secondary wetting on the steel surface. Especially, liquid Cu prefers spreading laterally and vertically along the grain boundaries of the steel substrate. In spite of rather similar mechanisms, CuGa10 wets 304L steel at lower rate than pure Cu above the liquidus temperature.

  14. The effect of anisotropy on the intermediate and final form in deep drawing of SS304L, with high draw ratios: Experimentation and numerical simulation

    Science.gov (United States)

    Qayyum, F.; Shah, M.; Muqeet, A.; Afzal, J.

    2016-08-01

    High deep draw ratio of metal sheets is often required in industry to produce complex structural components and is considered to be problematic beyond a draw ratio of 1.7. In addition, anisotropy of material plays a great role in the final form of deep drawn products. In this research AISI SS304 L high draw ratio deep drawing (HDR) cups have been developed by using multiple intermediate annealing steps. The form of flange produced at each draw step is recorded, Numerical simulation of the process is carried out using ABAQUS StandardTM. Accurate modelling of the process requires anisotropic parameters. Tensile tests at 0o, 15o, 30o, 45o, 60o, 75o, 90o to the rolling direction are carried out to determine the Lankford coefficients and hardening coefficients in each direction. The detailed material data obtained is then applied to simulate the HDR process. The forms recorded experimentally are compared with simulation results and conclusion is drawn as to the accuracy of the simulation.

  15. Effects of stop-start features on residual stresses in a multipass austenitic stainless steel weld

    Energy Technology Data Exchange (ETDEWEB)

    Turski, M., E-mail: Mark.Turski@magnesium-elektron.com [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom); Francis, J.A. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom)] [Materials Engineering, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Hurrell, P.R. [Rolls-Royce Plc., Raynesway, Derby DE21 7XX (United Kingdom); Bate, S.K. [Serco Technical Services, Birchwood Park, Warrington, Cheshire WA3 6GA (United Kingdom); Hiller, S. [Materials Engineering, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Withers, P.J. [School of Materials, University of Manchester, Grosvenor Street, Manchester M1 7HS (United Kingdom)

    2012-01-15

    In this article we describe experiments that characterise and quantify the localised perturbations in residual stress associated with both ramped and abrupt stop-start features in a multipass weld. Residual stress distributions in AISI Grade 304L/308L stainless steel groove-welded specimens, containing weld interruptions that were introduced in a controlled manner, have been characterised using both neutron diffraction and the incremental deep hole drilling method. The extent to which the localised stresses associated with the interruptions were annealed by overlayed passes was also assessed. The results suggest that, regardless of the type of interruption, there can be significant localised increases in residual stress if the stop-start feature is left exposed. If further weld passes are deposited, then the localised increases in stress are likely to persist if the interruption was abrupt, whereas for a ramped interruption they may be dissipated. - Highlights: Black-Right-Pointing-Pointer In this study the residual stress-field surrounding weld interruptions was measured. Black-Right-Pointing-Pointer Localised stresses were found to increase at weld interruptions. Black-Right-Pointing-Pointer Both ramped and abrupt weld interruptions were investigated. Black-Right-Pointing-Pointer After subsequent weld passes, localised stresses persisted for abrupt interruptions. Black-Right-Pointing-Pointer After subsequent weld passes, localised stresses dissipated for ramped interruptions.

  16. Sigma phase formation kinetics in stainless steel laminate composites

    Energy Technology Data Exchange (ETDEWEB)

    Wenmen, D.W.; Olson, D.L.; Matlock, D.K. [Colorado School of Mines, Golden, CO (United States)] [and others

    1994-12-31

    Stainless steel laminate composites were made to simulate weld microstructures. The use of laminates with variations in chemical composition allows for one dimensional analysis of phase transformation associated with the more complex three-dimensional solidification experience of weld metal. Alternate layers of austenitic (304L and 316L) and ferritic (Ebrite) stainless steels allowed for the study of sigma phase formation at the austenite-ferrite interface in duplex stainless steel. Two austenitic stainless steels, 304L (18.5Cr-9.2Ni-0.3Mo) and 316L (16.2Cr-10.1Ni-2.6Mo), and one ferritic stainless steel, Ebrite (26.3Cr-0Ni-1.0Mo) were received in the form of sheet which was laboratory cold rolled to a final thickness of 0.25 mm (0.030 in.). Laminate composites were prepared by laboratory hot rolling a vacuum encapsulated compact of alternating layers of the ferrite steel with either 304L or 316L stainless steel sheets. Laminate composite specimens, which simulate duplex austenite-ferrite weld metal structure, were used to establish the kinetics of nucleation and growth of sigma phase. The factors affecting sigma phase formation were identified. The effects of time, temperature, and transport of chromium and nickel were evaluated and used to establish a model for sigma phase formation in the austenite-ferrite interfacial region. Information useful for designing stainless steel welding consumables to be used for high temperature service was determined.

  17. An investigation on weldability of AISI 304 and AISI 1040 steels on friction welding; Untersuchung der Schweisseignung von AISI 304 und AISI 1040 mittels Reibschweissen

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Sare; Ay, Irfan [Balikesir Univ., Cagis Campus (Turkey). Mechanical Eng. Dept.; Dinc, Dincer [General Directorate of Highways, Canakkale (Turkey); Yaman, Ramazan [Balikesir Univ., Cagis Campus (Turkey). Industrial Eng. Dept.

    2010-04-15

    In welding technology, joining processes of different materials, which have dissimilar crystal structures are difficult. Welding of different materials becomes very important to reduce costs. Furthermore, the friction welding method is processed in lower temperature than the melting temperature. Especially, this is a big advantage to overcome difficulties that occur in the heat affected zone during usage of conventional methods. In this study, the weldability of AISI 304 stainless steel and AISI 1040 carbon steel by friction welding is studied. During the welding process, temperature variations in the welding zones were measured with an infrared temperature measurement device. After welding of the samples, tensile and hardness experiments were carried out. For metallographic investigations, optical microscope and scanning electron microscope (SEM) pictures were taken. Energy dispersive spectroscopy (EDS) analysis was carried out for composition investigations on welding and heat affected zones. As a result, these two steels could be joined by friction welding for industrial usage.

  18. Antibacterial silver nanocluster/silica composite coatings on stainless steel

    Science.gov (United States)

    Ferraris, M.; Perero, S.; Ferraris, S.; Miola, M.; Vernè, E.; Skoglund, S.; Blomberg, E.; Odnevall Wallinder, I.

    2017-02-01

    A coating made of silver nanocluster/silica composites has been deposited, via a radio frequency (RF) co-sputtering technique, for the first time onto stainless steel (AISI 304L) with the aim to improve its antibacterial properties. Different thermal treatments after coating deposition have been applied in order to optimize the coating adhesion, cohesion and its antibacterial properties. Its applicability has been investigated at realistic conditions in a cheese production plant. The physico-chemical characteristics of the coatings have been analyzed by means of different bulk and surface analytical techniques. Field emission scanning electron microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS), contact angle measurements and atomic force microscopy (AFM) were employed to assess coating morphology, composition, surface roughness, wetting properties, size and local distribution of the nanoparticles within the coating. Tape tests were used to determine the adhesion/cohesion properties of the coating. The amount and time-dependence of released silver in solutions of acetic acid, artificial water, artificial tap water and artificial milk were determined by means of Atomic Absorption Spectroscopy (AAS). The antibacterial effect of the coating was evaluated at different experimental conditions using a standard bacterial strain of Staphylococcus aureus in compliance with National Committee for Clinical Laboratory Standards (NCCLS) and AATCC 147 standards. The Ahearn test was performed to measure the adhesion of bacteria to the coated stainless steel surface compared with a control surface. The antibacterial coating retained its antibacterial activity after thermal treatment up to 450 °C and after soaking in common cleaning products for stainless steel surfaces used for e.g. food applications. The antibacterial capacity of the coating remained at high levels for 1-5 days, and showed a good capacity to reduce the adhesion of bacteria up to 30 days. Only a few

  19. Material Characterization of Fatigue Specimens made from Meta-stable Austenitic Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Niffenegger, M.; Grosse, M.; Kalkhof, D.; Leber, H. [Paul Scherrer Institut Villigen (Switzerland); Vincent, A.; Pasco, L.; Morin, M. [Insa de Lyon (France)

    2003-07-01

    The main objective of the EU-project CRETE (Contract No.: FIS5-1999-00280) was to assess the capability and the reliability of innovative NDT-inspection techniques for the detection of material degradation, induced by thermal fatigue and neutron irradiation, of metastable austenitic and ferritic low-alloy steel. Several project partners tested aged or irradiated samples, using various techniques (acoustic, magnetic and thermoelectric). However, these indirect methods require a careful interpretation of the measured signal in terms of micro-structural evolutions due to ageing of the material. Therefore the material had to be characterized in its undamaged, as well as in its damaged state. The present report summarises only the material characterization of the fatigue specimens. It is issued simultaneously as an PSI Bericht and the CRETE work package 3 (WP3) report. Each partner according to their own specifications purchased three materials under investigation, namely AISI 347, AISI 321 and AISI 304L. After sending the material to PSI, all fatigue specimens were manufactured by the same Swiss company. Each partner was responsible for his fatigue tests which are documented in the report WP1, written by FANP. In order to characterize the material in its unfatigued as well as in its fatigued state and to consider microstructural changes related to fatigue damage the methods listed below were employed either by PSI or by INSA de Lyon: (1) Inductive Coupled Plasma Emission Photometry (ICP-OES) was applied to determine the chemical composition, (2) Scanning electron microscopy (SEM) for observing cracks, slip bands between grain and twin boundaries, - Ferromaster for measuring the magnetic permeability, (3) Physical Properties Measuring System (PPMS) for measuring magnetization characteristics, (4) Neutron- and advanced X-ray diffraction methods for the quantitative determination of martensite, - Transmission electron microscopy (TEM) for the observation of crystalline

  20. Dense plasma focus-assisted nitriding of AISI-304

    Science.gov (United States)

    Shafiq, M.; Asghar, M.; Ahmad, S.; Sadiq, M.; Qayyum, A.; Zakaullah, M.

    Nitrogen ion implantation into AISI-304 stainless steel is carried out using a dense plasma focus device, operated at a charging voltage of 18 kV (discharge energyD1.45 kJ) with nitrogen filling at optimum pressure of 0.75 mbar. AISI-304 stainless steel samples placed axially above the anode tip are exposed to the ions for 10, 20 and 30 focus shots. X-ray diffraction (XRD), Vickers's micro hardness tester, scanning electron microscopy, and energy dispersive X-ray spectroscopy are used to explore the ion induced changes in the crystallographic structures, surface morphology, elemental composition and surface hardness of the ion irradiated samples. The XRD pattern confirms the formation of an expanded austenite phase, owing to nitrogen incorporated into the existing iron lattice. The results of micro hardness tester show that the hardness is increased about three times at an axial distance of 5 cm for 20 shots.

  1. Weldability of AISI 304 to copper by friction welding

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Balalan, Zulkuf [Firat Univ., Elazig (Turkey)

    2013-06-01

    Friction welding is a solid-state welding method, which can join different materials smoothly and is excessively used in manufacturing industry. Friction welding method is commonly used in welding applications of especially cylindrical components, pipes and materials with different properties, for which other welding methods remain incapable. AISI 304 stainless steel and a copper alloy of 99.6 % purity were used in this study. This couple was welded in the friction welding machine. After the welding process, samples were analyzed macroscopically and microscopically, and their microhardness was measured. Tensile test was used to determine the bond strength of materials that were joined using the friction welding method. At the end of the study, it was observed that AISI 304 stainless steel and copper could be welded smoothly using the friction welding method and the bond strength is close to the tensile strength of copper. (orig.)

  2. Corrosion resistance of the welded AISI 316L after various surface treatments

    Directory of Open Access Journals (Sweden)

    Tatiana Liptáková

    2014-01-01

    Full Text Available The main aim of this work is to monitor the surface treatment impact on the corrosion resistance of the welded stainless steel AISI 316L to local corrosion forms. The excellent corrosion resistance of austenitic stainless steel is caused by the existence of stable, thin and well adhering passive layer which quality is strongly influenced by welding. Therefore surface treatment of stainless steel is very important with regard to its local corrosion susceptibility Surfaces of welded stainless steel were treated by various mechanical methods (grinding, garnet blasting. Surface properties were studied by SEM, corrosion resistance was evaluated after exposition tests in chlorides environment using weight and metalographic analysis. The experimental outcomes confirmed that the mechanical finishing has a significant effect on the corrosion behavior of welded stainless steel AISI 316L.

  3. The aluminizing in powder technology of AISI 304 steel

    Science.gov (United States)

    Băitanu, D. B.; Găluşcă, D. G.; Achiţei, D. C.; Minciună, M. G.; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    The paper presents a study about the aluminizing treatments applied to AISI 304 stainless steel, with the purpose to improve the corrosion resistance. The aluminizing is realized in a powder medium, composed by aluminium powder (with 99.95% purity), aluminium oxide Al2O3 and ammonium chloride NH4Cl. The structural characterization was made by scanning electronic microscopy to highlight the structure of layer after aluminizing, at different magnitudes.

  4. Properties of high-frequency sub-wavelength ripples on stainless steel 304L under ultra short pulse laser irradiation

    NARCIS (Netherlands)

    Mitko, V.S.; Röer, G.R.B.E.; Huis in 't veld, A.J.; Skolski, J.Z.P.; Obona, J.V.; Ocelík, V.; Hosson, J.T.M.de

    2011-01-01

    The paper concentrates on surface texturing on sub-micro meter scale with ultra short laser pulses that has several applications, e.g. changing the hydrophilic/hydrophobic performance, optical or tribological properties of materials. In general, the formations of wavy structures, or ripples on a sur

  5. Properties of High-Frequency Sub-Wavelength Ripples on Stainless Steel 304L under Ultra Short Pulse Laser Irradiation

    NARCIS (Netherlands)

    Mitko, V.S.; Römer, G.R.B.E.; Huis in ‘t Veld, A.J.; Skolski, J.Z.P.; Obona, J.V.; Ocelík, V.; Hosson, J.T.M. De

    2011-01-01

    The paper concentrates on surface texturing on sub-micro meter scale with ultra short laser pulses that has several applications, e.g. changing the hydrophilic/hydrophobic performance, optical or tribological properties of materials. In general, the formations of wavy structures, or ripples on a sur

  6. MICROSTRUCTURE AND FATIGUE PROPERTIES OF DISSIMILAR SPOT WELDED JOINTS OF AISI 304 AND AISI 1008

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2013-06-01

    Full Text Available Carbon steel and stainless steel composites are being more frequently used for applications requiring a corrosion resistant and attractive exterior surface and a high strength structural substrate. Spot welding is a potentially useful and efficient jointing process for the production of components consisting of these two materials. The spot welding characteristics of weld joints between these two materials are discussed in this paper. The experiment was conducted on dissimilar weld joints using carbon steel and 304L (2B austenitic stainless steel by varying the welding currents and electrode pressing forces. Throughout the welding process; the electrical signals from the strain sensor, current transducer and terminal voltage clippers are measured in order to understand each and every millisecond of the welding process. In doing so, the dynamic resistances, heat distributions and forging forces are computed for various currents and force levels within the good welds’ regions. The other process controlling parameters, particularly the electrode tip and weld time, remained constant throughout the experiment. The weld growth was noted for the welding current increment, but in the electrode force increment it causes an adverse reaction to weld growth. Moreover, the effect of heat imbalance was clearly noted during the welding process due to the different electrical and chemical properties. The welded specimens finally underwent tensile, hardness and metallurgical testing to characterise the weld growth.

  7. Mechanisms-based viscoplasticity: Theoretical approach and experimental validation for steel 304L

    Science.gov (United States)

    Zubelewicz, Aleksander; Oliferuk, Wiera

    2016-03-01

    We propose a mechanisms-based viscoplasticity approach for metals and alloys. First, we derive a stochastic model for thermally-activated motion of dislocations and, then, introduce power-law flow rules. The overall plastic deformation includes local plastic slip events taken with an appropriate weight assigned to each angle of the plane misorientation from the direction of maximum shear stress. As deformation progresses, the material experiences successive reorganizations of the slip systems. The microstructural evolution causes that a portion of energy expended on plastic deformation is dissipated and the rest is stored in the defect structures. We show that the reorganizations are stable in a homogeneously deformed material. The concept is tested for steel 304L, where we reproduce experimentally obtained stress-strain responses, we construct the Frost-Ashby deformation map and predict the rate of the energy storage. The storage is assessed in terms of synchronized measurements of temperature and displacement distributions on the specimen surface during tensile loading.

  8. Deep drawing of 304 L Steel Sheet using Vegetable oils as Forming Lubricants

    Science.gov (United States)

    Shashidhara, Y. M.; Jayaram, S. R.

    2012-12-01

    The study involves the evaluation of deep drawing process using two non edible oils, Pongam (Pongammia pinnata) and Jatropha (Jatropha carcass) as metal forming lubricants. Experiments are conducted on 304L steel sheets under the raw and modified oils with suitable punch and die on a hydraulic press of 200 ton capacity. The punch load, draw-in-length and wall thickness distribution for deep drawn cups are observed. The drawn cups are scanned using laser scanning technique and 3D models are generated using modeling package. The wall thickness profiles of cups at different sections (or height) are measured using CAD package. Among the two raw oils, the drawn cups under Jatropha oil, have uniform wall thickness profile compared to Pongam oil. Uneven flow of material and cup rupturing is observed under methyl esters of Pongam and Jatropha oil lubricated conditions. However, the results are observed under epoxidised Jatropha oil with uniform metal flow and wall thicknesses compared to mineral and other versions of vegetable oils.

  9. Strain induced grain boundary migration effects on grain growth of an austenitic stainless steel during static and metadynamic recrystallization

    Energy Technology Data Exchange (ETDEWEB)

    Paggi, A., E-mail: alpaggi@tenaris.com [Tenaris Dalmine R& D, Dalmine S.p.A., Piazza Caduti 6 Luglio 1944 n.1, 24044 Dalmine (Italy); Angella, G.; Donnini, R. [National Research Council (CNR), Institute for Energetics and Interphases (IENI), Via Roberto Cozzi 53, 20125 Milano (Italy)

    2015-09-15

    Static and metadynamic recrystallization of an AISI 304L austenitic stainless steel was investigated at 1100 °C and 10{sup −} {sup 2} s{sup −} {sup 1} strain rate. The kinetics of recrystallization was determined through double hit compression tests. Two strain levels were selected for the first compression hit: ε{sub f} = 0.15 for static recrystallization (SRX) and 0.25 for metadynamic recrystallization (MDRX). Both the as-deformed and the recrystallized microstructures were investigated through optical microscopy and electron back-scattered diffraction (EBSD) technique. During deformation, strain induced grain boundary migration appeared to be significant, producing a square-like grain boundary structure aligned along the directions of the maximum shear stresses in compression. EBSD analysis revealed to be as a fundamental technique that the dislocation density was distributed heterogeneously in the deformed grains. Grain growth driven by surface energy reduction was also investigated, finding that it was too slow to explain the experimental data. Based on microstructural results, it was concluded that saturation of the nucleation sites occurred in the first stages of recrystallization, while grain growth driven by strain induced grain boundary migration (SIGBM) dominated the subsequent stages. - Highlights: • Recrystallization behavior of a stainless steel was investigated at 1100 °C. • EBSD revealed that the dislocation density distribution was heterogeneous during deformation. • Saturation of nucleation sites occurred in the first stages of recrystallization. • Strain induced grain boundary migration (SIGBM) effects were significant. • Grain growth driven by SIGBM dominated the subsequent stages.

  10. Metallurgical and Mechanical Research on Dissimilar Electron Beam Welding of AISI 316L and AISI 4340

    Directory of Open Access Journals (Sweden)

    A. R. Sufizadeh

    2016-01-01

    Full Text Available Dissimilar electron beam welding of 316L austenitic stainless steel and AISI 4340 low alloy high strength steel has been studied. Studies are focused on effect of beam current on weld geometry, optical and scanning electron microscopy, X-ray diffraction of the weld microstructures, and heat affected zone. The results showed that the increase of beam current led to increasing depths and widths of the welds. The optimum beam current was 2.8 mA which shows full penetration with minimum width. The cooling rates were calculated for optimum sample by measuring secondary dendrite arm space and the results show that high cooling rates lead to austenitic microstructure. Moreover, the metallography result shows the columnar and equiaxed austenitic microstructures in weld zone. A comparison of HAZ widths depicts the wider HAZ in the 316L side. The tensile tests results showed that the optimum sample fractured from base metal in AISI 316L side with the UTS values is much greater than the other samples. Moreover, the fractography study presents the weld cross sections with dimples resembling ductile fracture. The hardness results showed that the increase of the beam current led to the formation of a wide softening zone as HAZ in AISI 4340 side.

  11. Comparison of the thermoelastic phenomenon expressions in stainless steels during cyclic loading

    Directory of Open Access Journals (Sweden)

    M. Sapieta

    2017-01-01

    Full Text Available The main purpose of this paper is to compare the thermoelastic stress in specimens of stainless steel. As material specimens we chose stainless steel of AISI 304, AISI 316Ti and AISI 316L types. The specimens were cyclically loaded with three-point bending. The whole process was recorded using an infrared camera. The thermal differences that occurred during the test were evaluated based on the thermoelastic stress equations. Subsequently, stress distributions in the specimens were compared for different types of stainless steel.

  12. Martensitic transformation during fatigue testing of an AISI 301LN steel

    OpenAIRE

    Mateo García, Antonio Manuel; Fargas Ribas, Gemma

    2012-01-01

    The plastic deformation accumulated during fatigue testing can induce the transformation of austenite to martensite in metastable austenitic stainless steels. To analyze this issue, a metastable austenitic stainless steel grade AISI 301 LN was studied in two different conditions, i.e. annealed and cold rolled. In the first case, the steel was fully austenitic, whereas cold rolled material had almost 30% of martensite. High cycle fatigue tests at a stress ratio of 0.8 were carried out on flat ...

  13. Influence of temperature on AISI 316L corrosion in phosphoric acid solutions under hydrodynamic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Tovar, R.; Montanes, M.T.; Garcia-Anton, J. [Valencia Univ. Politecnica, Dept. de Ingenieria Quimica y Nuclear. ETSI Industriales, Valencia (Spain); Ben Bachir, A.; Abdelkebir, B.; Elmandoubi, N. [University Mohammed V-Agdal, Lab. Corrosion-Electrochimie, Faculty of Sciences, Rabat (Morocco)

    2009-07-01

    AISI 316L stainless steel, due to its good mechanical properties and corrosion resistance, is widely used in the phosphoric acid industry, including piping lines. However, phosphoric acid (H{sub 3}PO{sub 4}) is a medium-strong acid, and corrosion problems could occur, especially working with concentrated solutions and increasing temperature. Furthermore, fluid flow can increase corrosion rates. The objective of this work is to study the dynamic corrosion of AISI 316L stainless steel in a range of temperature from 25 C to 60 C by means of cyclic potentiodynamic curves. A hydrodynamic circuit was used in order to study dynamic corrosion. The experiments were carried out in an oxygen-free environment at different Reynolds numbers: 1,456, 3,166 and 5,066. The results show that uniform corrosion mechanisms can be expected for AISI 316L stainless steel in 5.5 M H{sub 3}PO{sub 4} solutions, since no hysteresis loop was observed. Moreover, temperature affects the corrosion parameters obtained from the polarization curves. Temperature shifts corrosion potential to nobler values, reduces the passivity region and enhances passivation current density. On the other hand, little influence of Reynolds number was observed on AISI 316L stainless steel corrosion. (authors)

  14. Corrosion Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

    In this paper the corrosion properties of laser welded AISI 316L stainless steel are examined. A number of different welds has been performed to test the influence of the weld parameters of the resulting corrosion properties. It has been chosen to use the potential independent critical pitting...

  15. The sub-zero Celsius treatment of precipitation hardenable semi-austenitic stainless steel

    DEFF Research Database (Denmark)

    Villa, Matteo; Hansen, Mikkel Fougt; Somers, Marcel A. J.

    2015-01-01

    A precipitation hardenable semi-austenitic stainless steel AISI 632 grade was austenitized according to industrial specifications and thereafter subjected to isothermal treatment at sub-zero Celsius temperatures. During treatment, austenite transformed to martensite. The isothermal austenite...

  16. AISI304不锈钢熔化过程中夹杂物在固-液糊状区漂移与聚集行为的原位观察%IN SITU OBSERVATION ON MOVEMENT AND AGGLOMERATION OF INCLUSION IN SOLID LIQUID MUSH ZONE DURING MELTING OF STAINLESS STEEL AISI304

    Institute of Scientific and Technical Information of China (English)

    梁高飞; 王成全; 方园

    2006-01-01

    利用Confocal激光扫描显微镜原位观察了AISI304不锈钢熔化过程中夹杂物在固-液(S-L)糊状区内的漂移与聚集行为.结果显示,夹杂(SiO2-Al2O3-CaO-MgO复合氧化物)在未熔高温铁素体(δ)相间的液相通道中漂移,未熔δ相体积分数为70%时,夹杂的平均漂移速率为80 μm/s;近完全熔化时,远离S-L界面的夹杂漂移速率高达1500 μm/s,而S-L界面附近的夹杂速率在50-200 μm/s之间;随着熔化的进行,未熔δ相表面逐渐凹凸不平,出现"类亚晶界".δ相对其附近漂移的夹杂表现出较强的吸附作用;夹杂多在δ-L界面处聚集、自球化;δ相吸附提供了夹杂去除的潜在途径.分析了夹杂运动的动力学机制.

  17. Effects of nitrogen and hydrogen in argon shielding gas on bead profile, delta-ferrite and nitrogen contents of the pulsed GTAW welds of AISI 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Viyanit, Ekkarut [National Metal and Materials Technology Center (MTEC), Pathaumthani (Thailand). Failure Analysis and Surface Technology Lab; Hartung, Fritz; Lothongkum, Gobboon [Chulalongkom University, Bangkok (Thailand). Dept. of Metallurgical Engineering,; Phakpeetinan, Panyasak; Chianpairot, Amnuysak

    2016-08-01

    The general effects of 1, 2, 3 and 4 vol.-% nitrogen and 1, 5 and 10 vol.-% hydrogen in argon shielding gas on weld bead profile (depth/width ratio: D/W) and the δ-ferrite content of AISI 316L pulsed GTAW welds were investigated. The limits for imperfections for the quality levels of welds were based on ISO 5817 B. The plates with a thickness of 6 mm were welded at the flat position and the bead on plate. Increasing hydrogen content in argon shielding gas increases the D/W ratio. Excessive hydrogen addition to argon shielding gas will result in incompletely filled groove and excessive penetration of weld. Increasing welding speed decreases the weld-metal volume and the D/W ratios. Nitrogen addition to argon shielding gas has no effect on the D/W ratio. The addition of a mixture of nitrogen and hydrogen to argon shielding gas on the D/W ratio does not show any interaction between them. An effect on the D/W ratio can be exclusively observed as a function of hydrogen content. Increasing hydrogen content in argon shielding gas increases the δ-ferrite content of weld metal. Increasing either nitrogen content in shielding gas or welding speed decreases the δ-ferrite content of weld metal. The nitrogen addition increases the weld metal nitrogen content, however, the hydrogen addition leads to a decrease of weld metal nitrogen content.

  18. Improved impact toughness of 13Cr martensitic stainless steel hardened by laser

    Science.gov (United States)

    Tsay, L. W.; Chang, Y. M.; Torng, S.; Wu, H. C.

    2002-08-01

    The impact toughness of AISI 403 martensitic stainless steel plate and laser-hardened specimens tempered at various temperatures were examined. Phosphorus was the primary residual impurity responsible for tempered embrittlement of this alloy. The experimental result also indicated that AISI 403 stainless steel was very sensitive to reverse-temper embrittlement. The improved impact toughness of the laser-hardened specimen was attributed to the refined microstructure in the laser-hardened zone.

  19. Corrosion Properties of Sintered and Wrought Stainless Seel

    DEFF Research Database (Denmark)

    Mathiesen, Troels; Maahn, Ernst Emanuel

    1997-01-01

    The corrosion properties of a range of stainless steels produced by powder metallurgy (PM) are compared with wrought AISI304 and AISI316 Steel. Characterisation of the passivation properties in 0.5M H2SO4 and pittingresistance in 0.3% chloride solution by polarisation show properties...... of the sintered PM150 that are comparable or better than those of wrought 316 steel depending on the applied sintering technique....

  20. PERFORMANCE STUDY ON AISI316 AND AISI410 USING DIFFERENT LAYERED COATED CUTTING TOOLS IN CNC TURNING

    Directory of Open Access Journals (Sweden)

    K. RAJA

    2015-01-01

    Full Text Available Stainless steel (SS is used for many commercial and industrial applications owing to its high resistance to corrosion. It is too hard to machine due to its high strength and high work hardening property. A surface property such as surface roughness (SR is critical to the function-ability of machined components. SS is generally regarded as more difficult to machine material and poor SR is obtained during machining. In this paper an attempt has been made to investigate the SR produced by CNC turning on austenitic stainless steel (AISI316 and martensitic stainless steel (AISI410 by different cases of coated cutting tool used at dry conditions. Multilayered coated with TiCN/Al2O3, multilayered coated with Ti(C, N, B and single layered coated with TiAlN coated cutting tools are used. Experiments were carried out by using Taguchi’s L27 orthogonal array. The effect of cutting parameters on SR is evaluated and optimum cutting conditions for minimizing the SR are determined. Analysis of variance (ANOVA is used for identifying the significant parameters affecting the responses. Confirmation experiments are conducted to validate the results obtained from optimization.

  1. Thermomechanical behaviour of AISI 304 steels; Comportamiento termomecanico de aceros AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    El Wahabi, M.; Garcia, V. G.; Cabrera, J. M.; Prado, J. M.

    2001-07-01

    The hot deformation behaviour of three AISI 304 (H, L and HP) austenitic stainless steel with different carbon contents has been studied. An analysis of the parameters describing their hot flow curves was carried out. No heavy effect of the carbon content was found on most of the latter parameters. However, the work hardening and dynamic recovery behaviour showed clear differences depending on the given alloy, especially at high temperatures and low strain rates where the high carbon steel displayed larger work hardening and dynamic recovery rates than the other steels. The high purity steel (interstitial free) displayed the lower stress levels as its hardening rate was slower than in the other two steels. (Author) 16 refs.

  2. Thermal stability study for candidate stainless steels of GEN IV reactors

    Energy Technology Data Exchange (ETDEWEB)

    Simeg Veternikova, J., E-mail: jana.veternikova@stuba.sk [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Degmova, J. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pekarcikova, M. [Institute of Materials Science, Faculty of Materials Science and Technology, Slovak University of Technology, Paulinska 16, 917 24 Trnava (Slovakia); Simko, F. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia); Petriska, M. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Skarba, M. [Slovak University of Technology, Vazovova 5, 812 43 Bratislava (Slovakia); Mikula, P. [Institute of Nuclear and Physical Engineering, Faculty of Electrical and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Pupala, M. [Department of Molten Salts, Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, 845 36 Bratislava (Slovakia)

    2016-11-30

    Highlights: • Thermal resistance of advanced stainless steels were observed at 1000 °C. • GEN IV candidate steels were confronted to classic AISI steels. • ODS AISI 316 has weaker thermal resistance than classic AISI steel. • Ferritic ODS steels and NF 709 has better thermal resistance than AISI steels. - Abstract: Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  3. SnO2:F Coated Ferritic Stainless Steels for PEM Fuel Cell Bipolar Plates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Turner, J. A.

    2007-01-01

    Ferrite stainless steels (AISI441, AISI444, and AISI446) were successfully coated with 0.6 {micro}m thick SnO{sub 2}:F by low-pressure chemical vapor deposition and investigated in simulated PEMFC environments. The results showed that a SnO{sub 2}:F coating enhanced the corrosion resistance of the alloys in PEMFC environments, though the substrate steel has a significant influence on the behavior of the coating. ICP results from the testing solutions indicated that fresh AISI441 had the highest dissolution rates in both environments, and coating with SnO2:F significantly reduced the dissolution. Coating AISI444 also improved the corrosion resistance. Coating AISI446 steel further improved the already excellent corrosion resistance of this alloy. For coated steels, both potentiostatic polarizations and ICP results showed that the PEMFC cathode environment is much more corrosive than the anode one. More dissolved metallic ions were detected in solutions for PEMFC cathode environment than those in PEMFC anode environment. Sn{sup 2+} was detected for the coated AISI441 and AISI444 steels but not for coated AISI446, indicating that the corrosion resistance of the substrate has a significant influence on the dissolution of the coating. After coating, the ICR values of the coated steels increased compared to those of the fresh steels. The SnO{sub 2}:F coating seems add an additional resistance to the native air-formed film on these stainless steels.

  4. Influence of high pressure hydrogen environment on tensile and fatigue properties of stainless steels at low temperatures

    Science.gov (United States)

    Ogata, T.

    2012-06-01

    Hydrogen environment embrittlement (HEE) of stainless steels in the environment of high pressure and low temperature hydrogen gas was evaluated using a very simple mechanical properties testing procedure. In the method, the high-pressure hydrogen environment is produced just inside the hole in the specimen. In this work, the effects of HEE on fatigue properties for austenitic stainless steels SUS304L and SUS316L were evaluated at 298 and 190 K. The effects of HEE on the tensile properties of higher strength stainless steels, such as strain-hardened 316, SUS630, and other alloys, SUH660 and Alloy 718 were also examined. The less effect of HEE on fatigue properties of SUS316L and tensile properties of strain-hardened 316 were observed compared with SUS304L and other steels at room temperature and 190 K.

  5. Evaluation of performance of AISI 444 steel for application in distillation towers; Avaliacao do desempenho do aco AISI 444 para aplicacao como 'lining' em torres de destilacao

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, R.F.; Miranda, H.C. de; Farias, J.P. [Universidade Federal do Ceara (DEMM/UFC), Fortaleza, CE (Brazil). Dept. de Engenharia Metalurgica e de Materiais. Lab. de Caracterizacao de Materiais], e-mail: rf.guimaraes@yahoo.com.br

    2008-07-01

    In this work, the behavior of the AISI 444 ferritic stainless steel submitted to thermal fatigue test and their corrosion resistance in heavy crude oil was evaluated. The AWS E309MoL-16 and E316L-17 weld metal was employed as filler metal. Plates of the AISI 444 were welded on ASTM A-516 Gr. 60 plates and submitted to fatigue thermal cycle. Samples were extracted from plates welded and heat treated immersed in heavy crude oil at 300 deg C. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive of X-ray analysis (EDX) were used to characterize the microstructure and the corroded surface. The results show that the AISI 444 stainless steels did not present cracks after the thermal fatigue cycle and the heat treated immerse in heavy crude oil. The electrode AWS E309MoL-16 show better corrosion resistance than the AWS E316L-17. (author)

  6. Effect of heat treatment on the microstructure and mechanical properties of martensitic stainless-steel joints welded with austenitic stainless-steel fillers: Vpliv toplotne obdelave na mikrostrukturo in mehanske lastnosti martenzitnih nerjavnih spojev, varjenih z avstenitnimi nerjavnimi elektrodami:

    OpenAIRE

    Calik, Adnan; Mustafa Serdar KARAKAŞ

    2013-01-01

    AISI 422 martensitic stainless steels were welded according to the ISO 15792-1 standard with austenitic stainless-steel filler. The effects of tempering and preheating heat treatments were also evaluated. The microstructures of the welds were characterized with optical microscopy. Mechanical properties were determined via microhardness, tensile and fatigue tests, and compared to those of the unwelded AISI 422 steel. X-ray diffraction was used to characterize the phases present in the weld. Ch...

  7. Warm compacting behavior of stainless steel powders

    Institute of Scientific and Technical Information of China (English)

    肖志瑜; 柯美元; 陈维平; 召明; 李元元

    2004-01-01

    The warm compacting behaviors of four different kinds of stainless steel powders, 304L, 316L, 410L and 430L, were studied. The results show that warm compaction can be applied to stainless steel powders. The green densities and strengths of compacts obtained through warm compaction are generally higher than those obtained through cold compaction. The compacting behaviors in warm compaction and cold compaction are similar.Under the compacting pressure of 700 MPa, the warm compacted densities are 0. 10 - 0.22 g/cm3 higher than the cold compacted ones, and the green strengths are 11.5 %-50 % higher. The optimal warm compacting temperature is 100 - 110 ℃. In the die wall lubricated warm compaction, the optimum internal lubricant content is 0.2%.

  8. Atom probe, AFM, and STM studies on vacuum-fired stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Stupnik, A. [ACC Austria GmbH, 8280 Fuerstenfeld (Austria); Frank, P. [Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria); Leisch, M., E-mail: m.leisch@tugraz.at [Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria)

    2009-04-15

    The surface morphology of grades 304L and 316LN stainless steels, after low-temperature bake-out process and vacuum annealing, has been studied by atomic force microscopy (AFM) and scanning tunnelling microscopy (STM). The local elemental composition on the surface before and after thermal treatment has been investigated by atom probe (AP) depth profiling measurements. After vacuum annealing, AFM and STM show significant changes in the surface structure and topology. Recrystallization and surface reconstruction is less pronounced on the 316LN stainless steel. AP depth profiling analyses result in noticeable nickel enrichment on the surface of grade 304L samples. Since hydrogen recombination is almost controlled by surface structure and composition, a strong influence on the outgassing behaviour by the particular surface microstructure can be deduced.

  9. Atom probe, AFM, and STM studies on vacuum-fired stainless steels.

    Science.gov (United States)

    Stupnik, A; Frank, P; Leisch, M

    2009-04-01

    The surface morphology of grades 304L and 316LN stainless steels, after low-temperature bake-out process and vacuum annealing, has been studied by atomic force microscopy (AFM) and scanning tunnelling microscopy (STM). The local elemental composition on the surface before and after thermal treatment has been investigated by atom probe (AP) depth profiling measurements. After vacuum annealing, AFM and STM show significant changes in the surface structure and topology. Recrystallization and surface reconstruction is less pronounced on the 316LN stainless steel. AP depth profiling analyses result in noticeable nickel enrichment on the surface of grade 304L samples. Since hydrogen recombination is almost controlled by surface structure and composition, a strong influence on the outgassing behaviour by the particular surface microstructure can be deduced.

  10. Decomposition kinetics of expanded austenite with high nitrogen contents

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2006-01-01

    This paper addresses the decomposition kinetics of synthesized homogeneous expanded austenite formed by gaseous nitriding of stainless steel AISI 304L and AISI 316L with nitrogen contents up to 38 at.% nitrogen. Isochronal annealing experiments were carried out in both inert (N2) and reducing (H2......) atmospheres. Differential thermal analysis (DTA) and thermogravimetry were applied for identification of the decomposition reactions and X-ray diffraction analysis was applied for phase analysis. CrN precipitated upon annealing; the activation energies are 187 kJ/mol and 128 kJ/mol for AISI 316L and AISI 304L...

  11. Effects of Ti-C:H coating and plasma nitriding treatment on tribological, electrochemical, and biocompatibility properties of AISI 316L.

    Science.gov (United States)

    Kao, W H; Su, Y L; Horng, J H; Zhang, K X

    2016-08-01

    Ti-C:H coatings were deposited on original, nitrided, and polished-nitrided AISI 316L stainless steel substrates using a closed field unbalanced magnetron sputtering system. Sliding friction wear tests were performed in 0.89 wt.% NaCl solution under a load of 30 N against AISI 316L stainless steel, Si3N4, and Ti6Al4V balls, respectively. The electrochemical properties of the various specimens were investigated by means of corrosion tests performed in 0.89 wt.% NaCl solution at room temperature. Finally, the biocompatibility properties of the specimens were investigated by performing cell culturing experiments using purified mouse leukemic monocyte macrophage cells (Raw264.7). In general, the results showed that plasma nitriding followed by Ti-C:H coating deposition provides an effective means of improving the wear resistance, anti-corrosion properties, and biocompatibility performance of AISI 316L stainless steel.

  12. A comparative study of the mechanical properties and the behavior of carbon and boron in stainless steel cladding tubes fabricated by PM HIP and traditional technologies

    NARCIS (Netherlands)

    Shulga, A. V.

    2013-01-01

    The ring tensile test method was optimized and successfully used to obtain precise data for specimens of the cladding tubes of AISI type 316 austenitic stainless steels and ferritic-martensitic stainless steel. The positive modifications in the tensile properties of the stainless steel cladding tube

  13. The structural characterization of some biomaterials, type AISI 310, used in medicine

    Science.gov (United States)

    Minciuna, M. G.; Vizureanu, P.; Hanganu, C.; Achitei, D. C.; Popescu, D. C.; Focsaneanu, S. C.

    2016-06-01

    Orthopedics biomaterials are intended for implantation in the human body and substituted or help to repair of bones, cartilage or organ transplant, and tendons. At the end of the 20th century, the availability of materials for the manufacture implants used in medicine has been the same as for other industrial applications. The most used metals for manufacturing the orthopedics implants are: stainless steels, cobalt-chrome-molybdenum alloys, titanium and his alloys. The structural researches which are made in this paper, offer a complete analysis of AISI310 stainless steels, using: optical spectrometry, X-ray diffraction and scanning electronic microscopy.

  14. Nickel release from nickel-plated metals and stainless steels.

    Science.gov (United States)

    Haudrechy, P; Foussereau, J; Mantout, B; Baroux, B

    1994-10-01

    Nickel release from nickel-plated metals often induces allergic contact dermatitis, but, for nickel-containing stainless steels, the effect is not well-known. In this paper, AISI 304, 316L, 303 and 430 type stainless steels, nickel and nickel-plated materials were investigated. 4 tests were performed: patch tests, leaching experiments, dimethylglyoxime (DMG) spot tests and electrochemical tests. Patch tests showed that 96% of the patients were intolerant to Ni-plated samples, and 14% to a high-sulfur stainless steel (303), while nickel-containing stainless steels with a low sulfur content elicited no reactions. Leaching experiments confirmed the patch tests: in acidic artificial sweat, Ni-plated samples released about 100 micrograms/cm2/week of nickel, while low-sulfur stainless steels released less than 0.03 microgram/cm2/week of nickel, and AISI 303 about 1.5 micrograms/cm2/week. Attention is drawn to the irrelevance of the DMG spot test, which reveals Ni present in the metal bulk but not its dissolution rate. Electrochemical experiments showed that 304 and 316 grades remain passive in the environments tested, while Ni-plated steels and AISI 303 can suffer significant cation dissolution. Thus, Ni-containing 304 and 316 steels should not induce contact dermatitis, while 303 should be avoided. A reliable nitric acid spot test is proposed to distinguish this grade from other stainless steels.

  15. Microstructural Characterization of Low Temperature Gas Nitrided Martensitic Stainless Steel

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work presents microstructural investigations of the surface zone of low temperature gas nitrided precipitation hardening martensitic stainless steel AISI 630. Grazing incidence X-ray diffraction was applied to investigate the present phases after successive removal of very thin sections...

  16. Paraequilibrium Carburization of Duplex and Ferritic Stainless Steels

    Science.gov (United States)

    Michal, G. M.; Gu, X.; Jennings, W. D.; Kahn, H.; Ernst, F.; Heuer, A. H.

    2009-08-01

    AISI 301 and E-BRITE stainless steels were subjected to low-temperature (743 K) carburization experiments using a commercial technology developed for carburization of 316 austenitic stainless steels. The AISI 301 steel contained ~40 vol pct ferrite before carburization but had a fully austenitic hardened case, ~20- μm thick, and a surface carbon concentration of ~8 at. pct after treatment; this “colossal” paraequilibrium carbon supersaturation caused an increase in lattice parameter of ~3 pct. The E-BRITE also developed a hardened case, 12- to 18- μm thick, but underwent a more modest (~0.3 pct) increase in lattice parameter; the surface carbon concentration was ~10 at. pct. While the hardened case on the AISI 301 stainless steel appeared to be single-phase austenite, evidence for carbide formation was apparent in X-ray diffractometer (XRD) scans of the E-BRITE. Paraequilibrium phase diagrams were calculated for both AISI 301 and E-BRITE stainless steels using a CALPHAD compound energy-based interstitial solid solution model. In the low-temperature regime of interest, and based upon measured paraequilibrium carbon solubilities, more negative Cr-carbon interaction parameters for austenite than those in the current CALPHAD data base may be appropriate. A sensitivity analysis involving Cr-carbon interaction parameters for ferrite found a strong dependence of carbon solubility on relatively small changes in the magnitude of these parameters.

  17. Effects of Nb on the microstructure and corrosive property in the Alloy 690-SUS 304L weldment

    Energy Technology Data Exchange (ETDEWEB)

    Jeng, S.L. [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)]. E-mail: sl_jeng@hotmail.com; Lee, H.T. [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)]. E-mail: htlee@mail.ncku.edu.tw; Rehbach, W.P. [Central Facility for Electron Microscopy, Aachen University of Technology (RWTH) (Germany)]. E-mail: rehbach@gfe.rwth-aachen.de; Kuo, T.Y. [Department of Mechanical Engineering, Southern Taiwan University of Technology, Tainan 710, Taiwan (China)]. E-mail: tykuo@mail.stut.edu.tw; Weirich, T.E. [Central Facility for Electron Microscopy, Aachen University of Technology (RWTH) (Germany); Mayer, J.P. [Central Facility for Electron Microscopy, Aachen University of Technology (RWTH) (Germany)

    2005-04-25

    A study of the microstructure and corrosion of dissimilar weldments of Alloy 690 and SUS 304L with various additions of niobium (Nb) (0.1, 1.03, 2.49, and 3.35% by weight) in the flux of coated electrodes is presented. With identical welding parameters and procedures, the weldments were butt-welded in three layers by shielding metal arc welding (SMAW), with each layer being deposited in a single pass. The results show that the dendritic microstructure in the fusion zone changed from a cellular to columnar dendrite and equiaxed dendrite with increasing Nb addition. Furthermore, the interdendritic phase increased in volume and changed in composition from an Al-Ti oxide to a mixture of Nb-Si phase and Nb-rich phase. Nevertheless, it was clearly observed that Cr{sub 7}C{sub 3} precipitated at the grain boundaries of the low Nb weldment root pass. Finally, the results revealed that corrosion occurs primarily at the grain boundaries and within the interdendritic regions of the weldements irrespective of the level of Nb addition. For the region of abundant formation of Nb-rich phase, the high-Nb weldment had a relatively low corrosion resistance.

  18. Surface fatigue and failure characteristics of hot-forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    Science.gov (United States)

    Townsend, Dennis P.

    1987-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground AISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  19. Effects of a high magnetic field on fracture toughness at 4. 2 K for austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Murase, S.; Kobatake, S.; Tanaka, M.; Tashiro, I.; Horigami, O.; Ogiwara, H. (Toshiba R and D Center, Kawasaki (Japan)); Shibata, K. (Univ. Tokyo, Bunkyo (Japan)); Nagai, K.; Ishikawa, K. (National Research Inst. for Metals, Sengen, Tsukuba (Japan))

    1993-01-01

    Structural stainless steels for cryogenic use in superconducting magnets for fusion reactors are used under high magnetic field and stress. The authors have performed fracture thoughness tests, using the unloading compliance method at 4.2 K on SUS304, 316LN and 304L stainless steels precracked at 77 K, in a varying magnetic field (0 and 8 T). Fracture toughness values (J[sub IC]) for 304 and 316LN steels at 8 T decreased by 17 and 20%, respectively, as compared with the 0 T condition. On the other hand, J[sub IC] for 304L steel was 30% increased by applying a high magnetic field of 8 T. Details of martensite formation and austenite stability are considered in discussion. (orig.).

  20. Can the Point Defect Model Explain the Influence of Temperature and Anion Size on Pitting of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Blackwood, Daniel J. [National University of Singapore, Singapore (Singapore)

    2015-12-15

    The pitting behaviours of 304L and 316L stainless steels were investigated at 3 °C to 90 °C in 1 M solutions of NaCl, NaBr and NaI by potentiodynamic polarization. The temperature dependences of the pitting potential varied according to the anion, being near linear in bromide but exponential in chloride. As a result, at low temperatures grades 304L and 316L steel are most susceptible to pitting by bromide ions, while at high temperatures both stainless steels were more susceptible to pitting by small chloride anions than the larger bromide and iodide. Thus, increasing temperature appears to favour attack by smaller anions. This paper will attempt to rationalise both of the above findings in terms of the point defect model. Initial findings are that qualitatively this approach can be reasonably successful, but not at the quantitative level, possibly due to insufficient data on the mechanical properties of thin passive films.

  1. An experience with in-service fabrication and inspection of austenitic stainless steel piping in high temperature sodium system

    Energy Technology Data Exchange (ETDEWEB)

    Ravi, S., E-mail: sravi@igcar.gov.in; Laha, K.; Sakthy, S.; Mathew, M.D.; Bhaduri, A.K.

    2015-04-01

    Highlights: • Procedure for changing 304L SS pipe to 316L SS in sodium loop has been established. • Hot leg made of 304L SS was isolated from existing cold leg made of 316LN SS. • Innovative welding was used in joining the new 316L SS pipe with existing 316LN SS. • The old components of 304L SS piping have been integrated with the new piping. - Abstract: A creep testing facility along with dynamic sodium loop was installed at Indira Gandhi Centre for Atomic Research, Kalpakkam, India to assess the creep behavior of fast reactor structural materials in flowing sodium. Type 304L austenitic stainless steel was used in the low cross section piping of hot-leg whereas 316LN austenitic stainless steel in the high cross section cold-leg of the sodium loop. The intended service life of the sodium loop was 10 years. The loop has performed successfully in the stipulated time period. To enhance its life time, it has been decided to replace the 304L piping with 316L piping in the hot-leg. There were more than 300 welding joints involved in the integration of cold-leg with the new 316L hot-leg. Continuous argon gas flow was maintained in the loop during welding to avoid contamination of sodium residue with air. Several innovative welding procedures have been adopted for joining the new hot-leg with the existing cold-leg in the presence of sodium residue adopting TIG welding technique. The joints were inspected for 100% X-ray radiography and qualified by performing tensile tests. The components used in the discarded hot-leg were retrieved, cleaned and integrated in the renovated loop. A method of cleaning component of sodium residue has been established. This paper highlights the in-service fabrication and inspection of the renovation.

  2. Welding Stainless Steels and Refractory Metals Using Diode-Pumped Continuous Wave Nd:YAG Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, T A; Elmer, J W; Pong, R; Gauthier, M D

    2004-09-27

    This report provides an overview of a series of developmental welding studies performed on a 2.2 kW Rofin Sinar DY-022 Diode Pumped Continuous Wave (CW) Nd:YAG welder at Lawrence Livermore National Laboratory (LLNL). Several materials systems, ranging from refractory metals, such as commercially pure tantalum and vanadium, to austenitic stainless steels, including both 304L and 21-6-9 grades, are examined. Power input and travel speed are systematically varied during the welding of each materials system, and the width, depth, and cross sectional area of the resulting weld fusion zones are measured. These individual studies are undertaken in order to characterize the response of the welder to changes in these welding parameters for a range of materials and to determine the maximum depth of penetration of which this welder is capable in each materials system. The maximum weld depths, which are on the order of 5.4 mm, are observed in the 21-6-9 austenitic stainless steel at the maximum laser power setting (2200 W) and a slow travel speed (6.4 mm/sec). The next highest weld depth is observed in the 304L stainless steel, followed by that observed in the vanadium and, finally, in the tantalum. Porosity, which is attributed to the collapse of the keyhole during welding, is also observed in the welds produced in tantalum, vanadium, and 304L stainless steel. Only the 21-6-9 austenitic stainless steel welds displayed little or no porosity over the range of welding parameters. Comparisons with similar laser welding systems are also made for several of these same materials systems. When compared with the welds produced by these other systems, the LLNL system typically produces welds of an equivalent or slightly higher depth.

  3. Surface fatigue and failure characteristics of hot forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    Science.gov (United States)

    Townsend, D. P.

    1986-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground SISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  4. New Stainless Steel Alloys for Low Temperature Surface Hardening?

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.

    2015-01-01

    The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE present...... in the stainless steel alloys. The presented computational approach for alloy design enables “screening” of hundreds of thousands hypothetical alloy systems by use of Thermo-Calc. Promising compositions for new stainless steel alloys can be selected based on imposed criteria, i.e. facilitating easy selection...

  5. EXAFS investigation of low temperature nitrided stainless steel

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas; Ståhl, Kenny

    2008-01-01

    Low temperature nitrided stainless steel AISI 316 flakes were investigated with EXAFS and X-ray diffraction analysis. The stainless steel flakes were transformed into a mixture of nitrogen expanded austenite and nitride phases. Two treatments were carried out yielding different overall nitrogen...... contents: (1) nitriding in pure NH3 and (2)nitriding in pure NH3 followed by reduction in H2. The majority of the Cr atoms in the stainless steel after treatment 1 and 2 was associated with a nitrogen–chromium bond distance comparable to that of the chemical compound CrN. The possibility of the occurrence...

  6. Attenuation of shock waves in copper and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, W.B.

    1986-06-01

    By using shock pins, data were gathered on the trajectories of shock waves in stainless steel (SS-304L) and oxygen-free-high-conductivity copper (OFHC-Cu). Shock pressures were generated in these materials by impacting the appropriate target with thin (approx.1.5 mm) flying plates. The flying plates in these experiments were accelerated to high velocities (approx.4 km/s) by high explosives. Six experiments were conducted, three using SS-304L as the target material and three experiments using OFHC-Cu as the target material. Peak shock pressures generated in the steel experiments were approximately 109, 130, and 147 GPa and in the copper experiments, the peak shock pressures were approximately 111, 132, and 143 GPa. In each experiment, an attenuation of the shock wave by a following release wave was clearly observed. An extensive effort using two characteristic codes (described in this work) to theoretically calculate the attenuation of the shock waves was made. The efficacy of several different constitutive equations to successfully model the experiments was studied by comparing the calculated shock trajectories to the experimental data. Based on such comparisons, the conclusion can be drawn that OFHC-Cu enters a melt phase at about 130 GPa on the principal Hugoniot. There was no sign of phase changes in the stainless-steel experiments. In order to match the observed attenuation of the shock waves in the SS-304L experiments, it was necessary to include strength effects in the calculations. It was found that the values for the parameters in the strength equations were dependent on the equation of state used in the modeling of the experiments. 66 refs., 194 figs., 77 tabs.

  7. SCC crack growth rate of cold-worked austenitic stainless steels in PWR primary water conditions

    Energy Technology Data Exchange (ETDEWEB)

    Guerre, C.; Raquet, O.; Herms, E. [Commissariat a l' Energie Atomique (CEA), DEN/DPC/SCCME/LECA, Gif-sur-Yvette Cedex (France); Marie, S. [Commissariat a l' Energie Atomique (CEA), DEN/DM2S/SEMT/LISN, Gif-sur-Yvette Cedex (France); Le Calvar, M. [Inst. for Radiological Protection and Nuclear Safety (IRSN), DSR/SAMS, Fontenay-aux-Roses Cedex (France)

    2007-07-01

    Stress corrosion cracking (SCC) of stainless steels (SS) is a significant cause of failure in the pressurized water reactors (PWR). Most of the reported case history failures of SS in PWR can be attributed to pollutants (chloride, sulphate) and / or locally oxygenated environments, even to sensitisation of the SS. However, some failures have been attributed to heavy cold work (CW) of SS. In laboratory tests, SCC initiation of cold-worked SS has been obtained using slow strain rate tests (SSRT) in nominal PWR environment. This paper describes constant load and cyclic crack growth rate (CGR) tests on cold-worked SS, on CT specimens. 304L and 316L have been tested with a CW up to 60 %. CW 316L is more prone to cracking than 304L. Over 30 % of CW, 316L is susceptible to crack propagation under constant load. CW is the main controlling parameter for cracking. (author))

  8. RESULTS OF EXPERIMENT TO DETERMINE CORROSION RATES FOR 304L IN HB-LINE DISSOLVER VESSEL VENTILATION SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J; Kathryn Counts, K

    2008-02-22

    Radioactive material being processed as part of the DE3013 program for HB-Line will result in the presence of chlorides, and in some cases fluorides, in the dissolver. Material Science and Technology developed an experimental plan to evaluate the impact of chloride on corrosion of the dissolver vessel ventilation system. The plan set test variables from the proposed operating parameters, previous test results, and a desired maximum chloride concentration for processing. The test variables included concentrations of nitric acid, fluorides and chlorides, and the presence of a welded and stressed metal coupon. Table 1 contains expected general corrosion rates in the HB-Line vessel vent system from dissolution of 3013 contents of varying nitric acid and chloride content. These general corrosion rates were measured upstream of the condenser in the experiment's offgas system near the entrance to the dissolver. However, they could apply elsewhere in the offgas system, depending on factors not simulated in the testing, including offgas system temperatures and airflow. Localized corrosion was significant in Tests One, Two, and Three. This corrosion is significant because it will probably be the first mode of penetration of the 304L steel in several places in the system. See Table 2. For Tests One and Three, the penetration rate of localized corrosion was much higher than that for general corrosion. It was approximately four times higher in Test One and at least 45 times higher in Test Three, penetrating an entire coupon thickness of 54 mils in 186 hours or less. There was no significant difference in corrosion between welded areas and un-welded areas on coupons. There was also no significant attack on stressed portions of coupons. It is probable that the lack of corrosion was because the stressed areas were facing downwards and offered no place for condensation or deposits to form. Had deposits formed, pitting may have occurred and led to stress corrosion cracking. The

  9. Influence of enzymatic reactions on the electrochemical behavior of EN X2CrNiMo17-11-2 (AISI 316L) stainless steel in bio-corrosion: role of interfacial processes on the modification of the passive layer; Influence des reactions enzymatiques sur le comportement electrochimique de l'acier inoxydable ENX2CrNiMo17-11-2 (AISI 316L) en biocorrosion: role des processus interfaciaux sur la modification du film passif

    Energy Technology Data Exchange (ETDEWEB)

    Landoulsi, J

    2008-01-15

    The outstanding corrosion behavior of stainless steels (SS) results from the presence of thin oxide layer (some nanometers). In non sterile aqueous media, stainless steels may exhibit a non stable behavior resulting from interactions between microbial species and passive film. In fact, microorganisms can be deeply involved in the corrosion processes usually reported as Microbial Influenced Corrosion (MIC). They can induce the initiation or the acceleration of this phenomenon and they do so when organized in bio-films. From the electrochemical point of view, stainless steels showed an increase of the free corrosion potential (Ecorr) attributed to the bio-film settlement. The Eco' ennoblement was broadly reported in seawater and seems to be confirmed in fresh water according to recent findings. A considerable progress in the comprehension of MIC processes was related to the role of extracellular species, essentially enzymes. Many enzymatic reactions occurring in bio-films consist on using oxygen as electron acceptor to generate hydrogen peroxide and related species. The aim of this work is to understand the mechanisms involved in the electrochemical behavior of stainless steel according to an enzymatic approach in medium simulating fresh water. To this end, glucose oxidase was chosen to globalize aerobic activities of bio-films. Electrochemical measurements in situ and surface analysis allow the comprehension of the role and the nature of interfacial processes. Surface characterization was performed with the help of a new quantitative utilization of XPS analysis and AFM. Results show a significant evolution in term of morphology (surface organization), (ii) chemical composition (passive layer, adsorbed organic species) and (iii) chemical reaction (oxidation, dissolution, effect of enzyme). Finally, a new enzymatic system is proposed to mimic specific physicochemical conditions at the SS / bio-film interface, in particular enzymatic generation of oxidant species

  10. Failure of Stainless Steel Welds Due to Microstructural Damage Prevented by In Situ Metallography

    Directory of Open Access Journals (Sweden)

    Juan Manuel Salgado Lopez

    Full Text Available Abstract In stainless steels, microstructural damage is caused by precipitation of chromium carbides or sigma phase. These microconstituents are detrimental in stainless steel welds because they lead to weld decay. Nevertheless, they are prone to appear in the heat affected zone (HAZ microstructure of stainless steel welds. This is particularly important for repairs of industrial components made of austenitic stainless steel. Non-destructive metallography can be applied in welding repairs of AISI 304 stainless steel components where it is difficult to ensure that no detrimental phase is present in the HAZ microstructure. The need of microstructural inspection in repairs of AISI 304 is caused because it is not possible to manufacture coupons for destructive metallography, with which the microstructure can be analyzed. In this work, it is proposed to apply in situ metallography as non-destructive testing in order to identify microstructural damage in the microstructure of AISI 304 stainless steel welds. The results of this study showed that the external surface micrographs of the weldment are representative of HAZ microstructure of the stainless steel component; because they show the presence of precipitated metallic carbides in the grain boundaries or sigma phase in the microstructure of the HAZ.

  11. Influence of plastic strain localization on the stress corrosion cracking of austenitic stainless steels; Influence de la localisation de la deformation plastique sur la CSC d'aciers austenitiques inoxydables

    Energy Technology Data Exchange (ETDEWEB)

    Cisse, S.; Tanguy, B. [CEA Saclay, DEN, SEMI, 91 - Gif-sur-Yvette (France); Andrieu, E.; Laffont, L.; Lafont, M.Ch. [Universite de Toulouse. CIRIMAT, UPS/INPT/CNRS, 31 - Toulous (France)

    2010-03-15

    The authors present a research study of the role of strain localization on the irradiation-assisted stress corrosion cracking (IASCC) of vessel steel in PWR-type (pressurized water reactor) environment. They study the interaction between plasticity and intergranular corrosion and/or oxidation mechanisms in austenitic stainless steels with respect to sublayer microstructure transformations. The study is performed on three austenitic stainless grades which have not been sensitized by any specific thermal treatment: the A286 structurally hardened steel, and the 304L and 316L austenitic stainless steels

  12. Improvement of mechanical properties on metastable stainless steels by reversion heat treatments

    OpenAIRE

    Mateo García, Antonio Manuel; Zapata, A.; Fargas Ribas, Gemma

    2013-01-01

    AISI 301LN is a metastable austenitic stainless steel that offers an excellent combination of high strength and ductility. This stainless grade is currently used in applications where severe forming operations are required, such as automotive bodies. When these metastable steels are plastically deformed at room temperature, for example by cold rolling, austenite transforms to martensite and, as a result, yield strength increases but ductility is reduced. Grain refinement is ...

  13. Improvement of Microhardness and Corrosion Resistance of Stainless Steel by Nanocomposite Coating

    OpenAIRE

    Hiba Husam Ismail; Kareem Neamah Sallomi; Hamid S. Mahdi

    2014-01-01

    Stainless steel (AISI 304) has good electrical and thermal conductivities, good corrosion resistance at ambient temperature, apart from these it is cheap and abundantly available; but has good mechanical properties such as hardness. To improve the hardness and corrosion resistance of stainless steel its surface can be modified by developing nanocomposite coatings applied on its surface. The main objective of this paper is to study effect of electroco-deposition method on microhardness and cor...

  14. Hydrogen solubility and diffusion in austenitic stainless steels studied with thermal desorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yagodzinskyy, Y.; Todoshchenko, O.; Papula, S.; Haenninen, H. [Laboratory of Engineering Materials, School of Science and Technology, Aalto University, Espoo (Finland)

    2011-01-15

    Hydrogen solubility and diffusion in austenitic stainless steels, namely AISI 310, AISI 301LN and AISI 201, are studied with thermal desorption spectroscopy (TDS) after electrochemical potentiostatic hydrogen pre-charging. Temperature dependencies of hydrogen desorption for all studied steels manifest a complex main peak caused by hydrogen releasing from the steel lattice by diffusion. Depending on the steel and heating rate the peak is situated from 350 to 500 K and its shape reflects a specific of hydrogen diffusion in stainless steels, which are multicomponent alloys. Analysis of the TDS curves is based on the hydrogen diffusion model taking into account trapping of hydrogen atoms in the energetically deep interstitial positions in the steel crystal lattice. Diffusion coefficient of hydrogen and its total content after the same charging procedure are obtained from the TDS curves and compared for the studied steels. (Copyright copyright 2011 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. TIG AISI-316 welds using an inert gas welding chamber and different filler metals: Changes in mechanical properties and microstructure

    Directory of Open Access Journals (Sweden)

    Sánchez, A.

    2010-12-01

    Full Text Available This report analyses the influence of the use of an inert gas welding chamber with a totally inert atmosphere on the microstructure and mechanical properties of austenitic AISI 316L stainless steel TIG welds, using AISI ER316L, AISI 308L and Inconel 625 as filler metals. When compared with the typical TIG process, the use of the inert gas chamber induced changes in the microstructure, mainly an increase in the presence of vermicular ferrite and ferrite stringers, what resulted in higher yield strengths and lower values of hardness. Its effect on other characteristics of the joins, such as tensile strength, depended on the filler metal. The best combination of mechanical characteristics was obtained when welding in the inert gas chamber using Inconel 625 as filler metal.

    En este estudio se analiza la influencia que el uso de una cámara de soldadura de gas inerte tiene sobre la microestructura y las propiedades mecánicas de las soldaduras TIG en el acero inoxidable austenítico AISI-316L cuando se emplean AISI ER316L, AISI 308L e Inconel 625 como materiales de aporte. Cuando se compara con el típico proceso de TIG, el uso de una cámara de gas inerte induce cambios en la microestructura, incrementando la presencia de ferrita vermicular y de laminillas de ferrita, resultando en un aumento del límite elástico y una pérdida de dureza. Su influencia sobre otras características de las soldaduras como la carga de rotura depende de la composición del material de aporte. La mejor combinación de propiedades mecánicas se obtuvo usando el Inconel 625 como material de aporte y soldando en la cámara de gas inerte.

  16. Study of creep cavitation in a stainless steel weldment

    OpenAIRE

    Jazaeri, H.; Bouchard, P. J.; Hutchings, M; Lindner, P.

    2012-01-01

    A study of creep cavities near reheat cracking in AISI Type 316H austenitic stainless steel headers, removed from long-time high temperature operation in nuclear power plants, is reported. It is shown how application of scanning electron microscopy (SEM), cryogenic fractography and small angle neutron scattering (SANS) can be applied, in a complementary way, to observe and quantify creep cavitation damage. Creep cavities in the vicinity of the crack are found to be mainly surrounding inter-gr...

  17. Erosion and Corrosion Behavior of Laser Cladded Stainless Steels with Tungsten Carbide

    Science.gov (United States)

    Singh, Raghuvir; Kumar, Mukesh; Kumar, Deepak; Mishra, Suman K.

    2012-11-01

    Laser cladding of tungsten carbide (WC) on stainless steels 13Cr-4Ni and AISI 304 substrates has been performed using high power diode laser. The cladded stainless steels were characterized for microstructural changes, hardness, solid particle erosion resistance and corrosion behavior. Resistance of the clad to solid particle erosion was evaluated using alumina particles according to ASTM G76 and corrosion behavior was studied by employing the anodic polarization and open circuit potential measurement in 3.5% NaCl solution and tap water. The hardness of laser cladded AISI 304 and 13Cr-4Ni stainless steel was increased up to 815 and 725Hv100 g, respectively. The erosion resistance of the modified surface was improved significantly such that the erosion rate of cladded AISI 304 (at 114 W/mm2) was observed ~0.74 mg/cm2/h as compared to ~1.16 and 0.97 mg/cm2/h for untreated AISI 304 and 13Cr-4Ni, respectively. Laser cladding of both the stainless steels, however, reduced the corrosion resistance in both NaCl and tap water.

  18. Very high cycle regime fatigue of thin walled tubes made from austenitic stainless steel

    DEFF Research Database (Denmark)

    Carstensen, J.V.; Mayer, H.; Brøndsted, P.

    2002-01-01

    Fatigue life data of cold worked tubes (diameter 4 mm, wall thicknesses 0.25 and 0.30 mm) of an austenitic stainless steel, AISI 904 L, were measured in the regime ranging from 2 × 105 to 1010 cycles to failure. The influence of the loading frequency was investigated as data were obtained...

  19. Influence of Plastic Deformation on Low Temperature Surface Hardening of Austenitic Stainless Steel by Gaseous Nitriding

    DEFF Research Database (Denmark)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin;

    2015-01-01

    This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of two commercial austenitic stainless steels: AISI 304 and EN 1.4369. The materials were plastically deformed to different equivalent strains by uniaxial...

  20. Corrosion of stainless steels by sulphur dioxide and chlorine in atmospheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, S.; Dhirendra, Dr.; Sanyal, B.; Pandey, G.N.

    1982-10-01

    This paper deals with the effect of sulphur dioxide and chlorine on stainless steels (AISI 304 and 321) under different atmospheric conditions. 70% RH value was found to be critical giving maximum corrosion. Potassium dichromate has been found to be a suitable passivating agent for protection against corrosion due to chlorine. (5 refs.)

  1. Étude par diffraction des rayons X de la nitruration plasma d'un acier 304L Influence sur l'oxydation à 1000 ^{circ}C

    Science.gov (United States)

    Marot, L.; Buscail, H.; Straboni, A.; Riffard, F.; Caudron, E.; Cueff, R.

    2002-07-01

    This work presents the influence of various nitridation parameters on the 304L steel oxidation at 1000 ^{circ}C, in air under atmospheric pressure. Nitridation temperatures were ranging between 300 ^{circ}C and 430 ^{circ}C with exposure times lasting from 2 to 8 hours. At 300 and 430 ^{circ}C, the nitridation treatment leads to the solid solution surface formation γ-N without any nitride formation. After oxidation at 1000 ^{circ}C of blank specimens, X ray diffraction reveals the FeCr2O4 spinel formation. This oxide does not act as a good diffusion barrier. With nitrogen treated specimens, the higher the nitridation temperature is and the longer the exposure time is, better is the oxidation behaviour at 1000 ^{circ}C. We then observe that the Cr{1,3}Fe{0,7}O3 oxide is more present in the oxide sale from the very beginning of the oxidation test which is correlated to a final lower mass gain. Cette étude porte sur l'influence des paramètres de nitruration plasma sur l'oxydation de l'acier 304L à 1000 ^{circ}C, sous air, à la pression atmosphérique. Les températures employées lors de la nitruration ont été de 300 ^{circ}C et 430 ^{circ}C pour des durées de nitruration variant entre 2 et 8 heures. A 300 et 430 ^{circ}C, la nitruration conduit à la formation d'une solution solide γ-N en surface sans provoquer la formation de nitrures. Après oxydation à 1000 ^{circ}C du 304L non nitruré, la diffraction des rayons X révèle la formation d'une couche de type spinelle FeCr2O4 qui ne semble pas jouer le rôle de barrière de diffusion. Pour les échantillons préalablement nitrurés, plus la température de nitruration est élevée et plus la durée du traitement est longue, meilleur est le comportement en oxydation. Nous observons alors l'oxyde Cr{1,3}Fe{0,7}O3 en proportion importante dès le début de l'oxydation et une prise de masse finale plus faible.

  2. Porosity in millimeter-scale welds of stainless steel : three-dimensional characterization.

    Energy Technology Data Exchange (ETDEWEB)

    Aagesen, Larry K. (University of Michigan, Ann Arbor, MI); Madison, Jonathan D.

    2012-05-01

    A variety of edge joints utilizing a continuous wave Nd:YAG laser have been produced and examined in a 304-L stainless steel to advance fundamental understanding of the linkage between processing and resultant microstructure in high-rate solidification events. Acquisition of three-dimensional reconstructions via micro-computed tomography combined with traditional metallography has allowed for qualitative and quantitative characterization of weld joints in a material system of wide use and broad applicability. The presence, variability and distribution of porosity, has been examined for average values, spatial distributions and morphology and then related back to fundamental processing parameters such as weld speed, weld power and laser focal length.

  3. 2014 Accomplishments-Tritium aging studies on stainless steel: Fracture toughness properties of forged stainless steels-Effect of hydrogen, forging strain rate, and forging temperature

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-02-01

    Forged stainless steels are used as the materials of construction for tritium reservoirs. During service, tritium diffuses into the reservoir walls and radioactively decays to helium-3. Tritium and decay helium cause a higher propensity for cracking which could lead to a tritium leak or delayed failure of a tritium reservoir. The factors that affect the tendency for crack formation and propagation include: Environment; steel type and microstructure; and, vessel configuration (geometry, pressure, residual stress). Fracture toughness properties are needed for evaluating the long-term effects of tritium on their structural properties. Until now, these effects have been characterized by measuring the effects of tritium on the tensile and fracture toughness properties of specimens fabricated from experimental forgings in the form of forward-extruded cylinders. A key result of those studies is that the long-term cracking resistance of stainless steels in tritium service depends greatly on the interaction between decay helium and the steels’ forged microstructure. New experimental research programs are underway and are designed to measure tritium and decay helium effects on the cracking properties of stainless steels using actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured should be more representative of actual reservoir properties because the microstructure of the specimens tested will be more like that of the tritium reservoirs. The programs are designed to measure the effects of key forging variables on tritium compatibility and include three stainless steels, multiple yield strengths, and four different forging processes. The effects on fracture toughness of hydrogen and crack orientation were measured for type 316L forgings. In addition, hydrogen effects on toughness were measured for Type 304L block forgings having two different yield strengths. Finally, fracture toughness properties of type 304L

  4. High temperature cyclic oxidation of AISI 310 steel in atmospheres with variable oxidation content; Oxidacion ciclica de un acero refractario AISI 310 a alta temperatura en atmosferas con centenidos de oxigeno variables

    Energy Technology Data Exchange (ETDEWEB)

    Higuera-Hidalgo, V.; Belzunce-Varela, F. J.; Riba-Lopez, J.

    2005-07-01

    High temperature oxidation test of an AISI 310 stainless steel was performed in two different environments: in an standard atmosphere (21% oxygen) at 704, 800, 884 and 1,000 degree centigree and in the typical environment of a gas turbine and vapor generator of a combined-cycle electric generation unit (10%oxygen) at 800 and 1,000 degree centigree. The oxidation kinetics was determined by means of the measurements of the weight gain per unit surface of the specimen and also determining the thickness of the oxide layer. Comparable results have been obtained using both methodologies and the effect of the oxygen content along with the other experimental differences were determined observing the oxidation kinetics in both environments. The cyclic oxidation of AISI 310 deteriorates at temperatures higher than 1,000 degree centigree. (Author) 9 refs.

  5. Modeling Finite Deformations in Trigonal Ceramic Crystals with Lattice Defects

    Science.gov (United States)

    2010-02-08

    plasticity and fracture in high density polycrystals: constitutive modeling and numerical simulation. J. Mech. Phys. Solids 53, 261– 301 . Clayton, J.D...Horstemeyer, M.F., Korellis, J.S., Grishabar, R.B., Mosher, D., 1998. High temperature sensitivity of notched AISI 304L stainless steel tests. Theor

  6. Passivation behavior of a ferritic stainless steel in concentrated alkaline solutions

    Directory of Open Access Journals (Sweden)

    Arash Fattah-alhosseini

    2015-10-01

    Full Text Available The passivation behavior of AISI 430 ferritic stainless steel was investigated in concentrated alkaline solutions in relation to several test parameters, using electrochemical techniques. Increasing solution pH (varying from 11.5 to 14.0 leads to an increase in the corrosion rate of the alloy. Mott–Schottky analysis revealed that passive films formed on AISI 430 ferritic stainless steel behave as n-type semiconductor and the donor densities increased with pH. Electrochemical impedance spectroscopy (EIS results showed that the reciprocal capacitance of the passive film is directly proportional to its thickness, which decreases with pH increase. The results revealed that for this ferritic stainless steel in concentrated alkaline solutions, decreasing the solution pH offers better conditions for forming passive films with higher protection behavior, due to the growth of a much thicker and less defective film.

  7. Effect of Hydrogen Charging on the Tensile and Constant Load Properties of an Austenitic Stainless Steel Weldment

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of cathodic hydrogen charging on the tensile and constant load properties was determined for an austenitic stainless steel weldment comprising a 304L steel in the solution treated condition as a base metal and a 308L filler steel as a weld metal. Part of the 304L solution treated steel was separately given additional sensitization treatment to simulate the microstructure that would develop in the heat affected zone. Tests were performed at room temperature on notched round bar specimens. Hydrogen charging resulted in a pronounced embrittlement of the tested materials. This was manifested mainly as a considerable loss in the dluctility of tensile specimens and a decrease in the time to failure and threshold stress of constant load specimens. The 308L weld metal exhibited the highest, and the 304L solution treated steel the lowest, resistance to hydrogen embrittlement. Hydrogen embrittlement was associated with the formation of strain induced martensite as well as a transition from brittle to ductile fracture morphology onwards the centre of the specimens.

  8. Surface-protein interactions on different stainless steel grades: effects of protein adsorption, surface changes and metal release.

    Science.gov (United States)

    Hedberg, Y; Wang, X; Hedberg, J; Lundin, M; Blomberg, E; Wallinder, I Odnevall

    2013-04-01

    Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed.

  9. Adsorption and protein-induced metal release from chromium metal and stainless steel.

    Science.gov (United States)

    Lundin, M; Hedberg, Y; Jiang, T; Herting, G; Wang, X; Thormann, E; Blomberg, E; Wallinder, I Odnevall

    2012-01-15

    A research effort is undertaken to understand the mechanism of metal release from, e.g., inhaled metal particles or metal implants in the presence of proteins. The effect of protein adsorption on the metal release process from oxidized chromium metal surfaces and stainless steel surfaces was therefore examined by quartz crystal microbalance with energy dissipation monitoring (QCM-D) and graphite furnace atomic absorption spectroscopy (GFAAS). Differently charged and sized proteins, relevant for the inhalation and dermal exposure route were chosen including human and bovine serum albumin (HSA, BSA), mucin (BSM), and lysozyme (LYS). The results show that all proteins have high affinities for chromium and stainless steel (AISI 316) when deposited from solutions at pH 4 and at pH 7.4 where the protein adsorbed amount was very similar. Adsorption of albumin and mucin was substantially higher at pH 4 compared to pH 7.4 with approximately monolayer coverage at pH 7.4, whereas lysozyme adsorbed in multilayers at both investigated pH. The protein-surface interaction was strong since proteins were irreversibly adsorbed with respect to rinsing. Due to the passive nature of chromium and stainless steel (AISI 316) surfaces, very low metal release concentrations from the QCM metal surfaces in the presence of proteins were obtained on the time scale of the adsorption experiment. Therefore, metal release studies from massive metal sheets in contact with protein solutions were carried out in parallel. The presence of proteins increased the extent of metals released for chromium metal and stainless steel grades of different microstructure and alloy content, all with passive chromium(III)-rich surface oxides, such as QCM (AISI 316), ferritic (AISI 430), austentic (AISI 304, 316L), and duplex (LDX 2205).

  10. A temperature dependent slip factor based thermal model for friction stir welding of stainless steel

    Indian Academy of Sciences (India)

    M Selvaraj

    2013-12-01

    This paper proposes a new slip factor based three-dimensional thermal model to predict the temperature distribution during friction stir welding of 304L stainless steel plates. The proposed model employs temperature and radius dependent heat source to study the thermal cycle, temperature distribution, power required, the effect of process parameters on heat generation per mm length of the weld and peak temperature during the friction stir welding process. Simulations of friction stir welding process were carried out on 304L stainless steel workpieces for various rotational and welding speeds. The predicted thermal cycle, power required and temperature distributions were found to be in good agreement with the experimental results. The heat generation per mm length of weld and peak temperature were found to be directly proportional to rotational speed and inversely proportional to welding speed. The rate of increase in heat generation per mm length of the weld and peak temperature are found to be higher at lower rotational speeds and lower at higher rotational speed. The heat generation during friction stir welding was found to be 80.8 % at shoulder, 16.1 % at pin side and 3.1 % at the bottom of the pin.

  11. Influence of Plastic Deformation on Low-Temperature Surface Hardening of Austenitic Stainless Steel by Gaseous Nitriding

    DEFF Research Database (Denmark)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin

    2015-01-01

    This article addresses an investigation of the influence of plastic deformation on low-temperature surface hardening by gaseous nitriding of two commercial stainless steels: EN 1.4369 and AISI 304. The materials were plastically deformed to several levels of equivalent strain by conventional...

  12. Surface integrity and part accuracy in reaming and tapping stainless steel with new vegetable based cutting oils

    DEFF Research Database (Denmark)

    Belluco, Walter; De Chiffre, Leonardo

    2002-01-01

    This paper presents an investigation on the effect of new formulations of vegetable oils on surface integrity and part accuracy in reaming and tapping operations with AISI 316L stainless steel. Surface integrity was assessed with measurements of roughness, microhardness, and using metallographic ...

  13. Study of the Intercrystalline Corrosion in Pipes of Stainless Steel in a Combined Cycle

    Directory of Open Access Journals (Sweden)

    Raúl Andrés Montejo Serrano

    2014-09-01

    Full Text Available The present work is carried out with the purpose of giving answer to the possible presence ofintercrystalline corrosion and its future consequences in the built tubes of stainless steel 304L anddedicated to the conduction from the water to the boilers of a combined cycle of electricity production.The plant is these in this moments in installation of process investor and assembly and this study wasrequested since during the trial of installation of the pipes of stainless steel that will drive the watertried to the steam generators, they were detected on the part of the operatives some imperfections inthe material, what generated the doubt about the possibility of presence of intercrystalline corrosion orof another type in the pipes. After the realized rehearsals according to international norms and alsousing rehearsals metallography you concludes that the material employee is not sensitive to this typeof corrosion.

  14. Influence of sintering atmosphere on the mechanical properties of steel P / M AISI 430L; Influencia de la atmosfera de sinterizacion en las propiedades mecanicas de los aceros P/M AISI 430L

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, F. J.; Martinez, C.; Costes, M. T.; Ruiz, J. M.; Garcia, L. E.; Corpas, F.

    2014-04-01

    It has studied the stainless steel powder metallurgy AISI 430L. It has compared the sintering in two different atmospheres; in vacuum, and in an atmosphere containing nitrogen. It has developed a heat treatment with the aim of improving the mechanical properties. This has been done through microstructural modification of complex nitrides of iron and chromium precipitates during the phase of sintering. Physical properties have been evaluated and are been performing a microstructural analysis for microstructure related to the increase in mechanical properties. (Author)

  15. Effect of internal heating during hot compression testing on the stress-strain behavior and hot working characteristics of Alloy 304L

    Energy Technology Data Exchange (ETDEWEB)

    Mataya, M.C.; Sackschewsky, V.E.

    1993-05-01

    Temperature change from conversion of deformation to internal heat, and its effect on stress-strain behavior of alloy 304L was investigated by initially isothermal (temperature of specimen, compression dies, environment equilibrated at initiation of test) uniaxial compression. Strain rate was varied 0.01 s{sup {minus}1} to 1 s{sup {minus}1} (thermal state of specimen varied from nearly isothermal to nearly adiabatic). Specimens were deformed at 750 to 1150 to a strain of 1. Change in temperature with strain was calculated via finite element analysis from measured stress-strain data and predictions were confirmed with thermocouples to verify the model. Temperature increased nearly linearly at the highest strain rate, consistent with temperature rise being a linear function of strain (adiabatic). As strain rate was lowered, heat transfer from superheated specimen to cooler dies caused sample temperature to increase and then decrease with strain as the sample thinned and specimen-die contact area increased. As-measured stress was corrected. Resulting isothermal flow curves were compared to predictions of a simplified method suggested by Thomas and Shrinivasan and differences are discussed. Strain rate sensitivity, activation energy for deformation, and flow curve peak associated with onset of dynamic recrystallization were determined from both as-measured and isothermal stress-strain data and found to vary widely. The impact of utilizing as-measured stress-strain data, not corrected for internal heating, on results of a number of published investigations is discussed.

  16. Liquid Phase Sintering of Highly Alloyed Stainless Steel

    DEFF Research Database (Denmark)

    Mathiesen, Troels

    1996-01-01

    Liquid phase sintering of stainless steel is usually applied to improve corrosion resistance by obtaining a material without an open pore system. The dense structure normally also give a higher strength when compared to conventional sintered steel. Liquid phase sintrering based on addition...... of boride to AISI 316L type steels have previously been studied, but were found to be sensitive to intergranular corrosion due to formation of intermetallic phases rich in chromium and molybdenum. In order to improve this system further, new investigations have focused on the use of higher alloyed stainless...... steel as base material. The stainless base powders were added different amounts and types of boride and sintered in hydrogen at different temperatures and times in a laboratory furnace. During sintering the outlet gas was analyzed and subsequently related to the obtained microstructure. Thermodynamic...

  17. Enhancement of Stainless Steel's Mechanical Properties via Carburizing Process

    Science.gov (United States)

    Ahmad, S.; Alias, S. K.; Abdullah, B.; Hafiz Mohd Bakri, Mohd.; Hafizuddin Jumadin, Muhammad; Mat Shah, Muhammad Amir

    2016-11-01

    Carburizing process is a method to disperse carbon into the steel surface in order to enhance its mechanical properties such as hardness and wear resistance. This paper study investigates the effect of carburizing temperature to the carbon dispersion layer in stainless steel. The standard AISI 304 stainless steel was carburized in two different temperatures which were 900°C and 950°C. The effect of carbon dispersion layers were observed and the results indicated that the increasing value of the average dispersion layer from 1.30 mm to 2.74 mm thickness was found to be related to increment of carburizing holding temperature . The increment of carbon thickness layer also resulted in improvement of hardness and tensile strength of carburized stainless steel.

  18. Characterization of AISI 4140 borided steels

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Silva, I., E-mail: icampos@ipn.mx [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Ortiz-Dominguez, M.; Lopez-Perrusquia, N.; Meneses-Amador, A. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Escobar-Galindo, R. [Instituto de Ciencia de Materiales de Madrid (CSIC), E-28049 Cantoblanco, Madrid (Spain); Martinez-Trinidad, J. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico)

    2010-02-01

    The present study characterizes the surface of AISI 4140 steels exposed to the paste-boriding process. The formation of Fe{sub 2}B hard coatings was obtained in the temperature range 1123-1273 K with different exposure times, using a 4 mm thick layer of boron carbide paste over the material surface. First, the growth kinetics of boride layers at the surface of AISI 4140 steels was evaluated. Second, the presence and distribution of alloying elements on the Fe{sub 2}B phase was measured using the Glow Discharge Optical Emission Spectrometry (GDOES) technique. Further, thermal residual stresses produced on the borided phase were evaluated by X-ray diffraction (XRD) analysis. The fracture toughness of the iron boride layer of the AISI 4140 borided steels was estimated using a Vickers microindentation induced-fracture testing at a constant distance of 25 {mu}m from the surface. The force criterion of fracture toughness was determined from the extent of brittle cracks, both parallel and perpendicular to the surface, originating at the tips of an indenter impression. The fracture toughness values obtained by the Palmqvist crack model are expressed in the form K{sub C}({pi}/2) > K{sub C} > K{sub C}(0) for the different applied loads and experimental parameters of the boriding process.

  19. Thermal fatigue cracking of austenitic stainless steels; Fissuration en fatigue thermique des aciers inoxydables austenitiques

    Energy Technology Data Exchange (ETDEWEB)

    Fissolo, A

    2001-07-01

    This report deals with the thermal fatigue cracking of austenitic stainless steels as AISI 316 LN and 304 L. Such damage has been clearly observed for some components used in Fast Breeder reactors (FBR) and Pressure Water Reactor (PWR). In order to investigate thermal fatigue, quasi-structural specimen have been used. In this frame, facilities enforcing temperature variations similar to those found under the operation conditions have been progressively developed. As for components, loading results from impeded dilatation. In the SPLASH facility, the purpose was to establish accurate crack initiation conditions in order to check the relevance of the usual component design methodology. The tested specimen is continuously heated by the passage of an electrical DC current, and submitted to cyclic thermal down shock (up to 1000 deg C/s) by means of periodical spraying of water on two opposite specimen faces. The number of cycles to crack initiation N{sub i} is deduced from periodic examinations of the quenched surfaces, by means of optical microscopy. It is considered that initiation occurs when at least one 50{mu}m to 150{open_square}m long crack is observed. Additional SPLASH tests were performed for N >> N{sub i}, with a view to investigate the evolution of a surface multiple cracking network with the number of cycles N. The CYTHIA test was mainly developed for the purpose of assessing crack growth dynamics of one isolated crack in thermal fatigue conditions. Specimens consist of thick walled tubes with a 1 mm circular groove is spark-machined at the specimen centre. During the test, the external wall of the tube is periodically heated by using a HF induction coil (1 MHz), while its internal wall is permanently cooled by flowing water. Total crack growth is derived from post-mortem examinations, whereby the thermal fatigue final rupture surface is oxidized at the end of the test. The specimen is broken afterwards under mechanical fatigue at room temperature. All the

  20. Effects of hydrogen concentration on slow crack growth in stainless steels

    Science.gov (United States)

    Singh, S.; Altstetter, C.

    1982-10-01

    The behavior of four austenitic stainless steel alloys containing bulk hydrogen contents up to 50 ppm by weight (0.28 at. pct) has been determined in sustained load and in slow strain rate tensile tests. Tests of these same alloys were also made in hydrogen gas. AISI 301 and two compositions of AISI 304 of different austenite stability showed typical three stage crack propagation regimes under sustained load. AISI 310S did not. The slow crack growth vs stress intensity relation was quite sensitive to hydrogen content above a minimum value and also sensitive to austenite stability. It was shown that hydrogen contents up to 40 wt ppm had no influence on the austenite stability at tensile elongations up to 60 pct. Fractographic and phase analysis results are presented, and a model for crack propagation is discussed.

  1. Damage mechanism at different transpassive potentials of solution-annealed 316 and 316l stainless steels

    Institute of Scientific and Technical Information of China (English)

    K Morshed Behbahani; M Pakshir; Z Abbasi; P Najafisayar

    2015-01-01

    Electrochemical impedance spectroscopy (EIS), anodic polarization and scanning electron microscopy techniques were used to investigate the damage mechanism in the transpassive potential region of AISI 316 and AISI 316L solution-annealed stainless steels (SS) with different degrees of sensitization. Depending on the DC potential applied during EIS tests, the AC responses in the transpassive region included three different regions:the first one associated with anodic dissolution of the passive layer, the second one contributed to the disso-lution at the area near grain boundaries, and the last one attributed to pitting corrosion. In addition, the fitting results to experimental data showed that as the DC bias during the EIS test increases the charge transfer resistance (Rct) decreases. Moreover, the Rct values decreased as the sensitization temperature increases but the AISI 316L SS samples exhibited a higher resistance to intergranular corrosion than 316 SS samples.

  2. Microstructure and antibacterial property of stainless steel implanted by Cu ions

    Institute of Scientific and Technical Information of China (English)

    XU Bo-fan; NI Hong-wei; XIONG Ping-yuan; XIONG Juan; DAN Zhi-gang

    2004-01-01

    Copper ions were implanted into AISI 304 austenitic stainless steel by metal vapor vacuum are (MEVVA) with 60 - 100 keV energy and a dose range (0.2 - 5.0) × 1017 cm-2. Then Cu-implanted stainless steel was treated by a special antibacterial treatment. Antibacterial rates of Cu-implanted stainless steel, Cu-implanted stainless steel with special antibacterial treatment and un-implanted stainless steel were obtained by agar plate method. Phase composition in the implanted layer was analyzed by glancing X-ray diffraction (GXRD). Microstructure of antibacterial stainless steel was observed with transmission electron microscopy (TEM), and changes of the bacterium appearance after 24 h antibacterial action on the surface of un-implanted and Cu-implanted stainless steel with antibacterial treatment were observed with bio-TEM respectively. The results show that stainless steel obtains antibacterial property against E. coli when the Cu ions dose approaches to the saturated one. A suitable amount of Cu-rich phase uniformly disperses on the surface of Cu-implanted stainless steel that is treated by the special antibacterial treatment. The Cu-rich phase naked on the surface has a function of damage to pericellular membrane and cell wall,the pericellular membrane is thickened and the karyon degraded, and finally, bacteria die. Cu-rich phase naked on the surface endows stainless steel with best antibacterial property.

  3. The corrosion behaviour of austenitic and duplex stainless steels in artificial saliva with the addition of fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Kocijan, Aleksandra, E-mail: Aleksandra.Kocijan@imt.s [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia); Merl, Darja Kek [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Jenko, Monika [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia)

    2011-02-15

    Research highlights: The corrosion behaviour of AISI 316L and 2205 DSS in orthodontics. The increased passive range for DSS 2205 compared to AISI 316L in artificial saliva. Higher R{sub p} values of DSS compared to AISI 316L in artificial saliva. The main constituent of the passive layers on DSS at the OCP in saliva was Cr-oxide. DSS 2205 is suitable for orthodontic applications in artificial saliva. - Abstract: The evolution of the passive films on 2205 duplex stainless steel (2205 DSS) and AISI 316L stainless steel in artificial saliva, and with the addition of fluoride, was studied using electrochemical impedance spectroscopy (EIS) and potentiodynamic measurements. The extent of the passive range increased for the 2205 DSS compared to the AISI 316L in both solutions. The formation of the passive film was studied by EIS at the open-circuit potential (OCP). The passive layers were studied at the OCP by X-ray photoelectron spectroscopy (XPS). The passive films on both materials predominantly contained Cr-oxides, whereas the Fe species were markedly depleted.

  4. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  5. Influence of Laser Peening on Phase Transformation and Corrosion Resistance of AISI 321 steel

    Science.gov (United States)

    Karthik, D.; Swaroop, S.

    2016-07-01

    The objective of this study is to investigate the influence of laser peening without coating (LPwC) on austenitic to martensitic (γ → α') phase transformation and corrosion behavior of austenitic stainless steel AISI 321 in 3.5% NaCl environment. Results indicate that LPwC induces a large compressive residual stresses of nearly -854 MPa and γ → α' phase transformation of about 18% (volume fraction). Microstructures of peened surface confirmed the γ → α' phase transformation and showed no grain refinement. Hardness increased slightly with a case depth of 900 μm. Despite the smaller surface roughness introduced, corrosion resistance improved after peening due to compressive residual stresses.

  6. Effect of cold work hardening on stress corrosion cracking of stainless steels in primary water of pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Raquet, O.; Herms, E. [CEA/Saclay, DEN/DPC, 91191 Gif sur Yvette Cedex (France); Vaillant, F.; Couvant, T.; Boursier, J.M. [EDF/Les Renardieres, R and D/MMC, 77250 Moret sur Loing (France)

    2004-07-01

    A R and D program is carried out in CEA and EDF laboratories to investigate separately the effects of factors which could contribute to IASCC mechanism. In the framework of this study, the influence of cold work on SCC of ASSs in primary water is studied to supply additional knowledge concerning the contribution of radiation hardening on IASCC of ASSs. Solution annealed ASSs, essentially of type AISI 304(L) and AISI 316(L), are generally considered very resistant to SCC in nominal primary water. However, Constant Extension Rate Tests (CERTs), performed on cold pressed humped specimens in nominal primary water at 360 deg. C, reveal that these materials can exhibit a high SCC susceptibility: deepest cracks reach 1 mm (mean crack growth rate about 1 {mu}m.h{sup -1}) and propagation is mainly intergranular for 304L and mainly transgranular for 316L. Indeed, work hardening in conjunction with high localized deformation can promote SCC. The influence of the nature of the cold work (shot peening, reaming, cold rolling, counter sinking, fatigue work hardening and tensile deformation) is investigated by means of screening CERTs performed with smooth specimens in 304L at 360 deg. C. For a given cold work hardening level, the susceptibility to crack initiation strongly depends on the cold working process, and no propagation is observed for a hardness level lower than 300 {+-}10 HV(0.49N). The propagation of cracks is observed only for dynamic loadings like CERT, traction/relaxation tests and crack growth rate tests performed with CT specimens under trapezoidal loading. Although crack initiation is observed for constant load and constant deformation tests, crack propagation do not seem to occur under these mechanical solicitations for 17000 hours of testing, even for hardness levels higher than 450 HV(0.49N). The mean crack growth rate increases when the hardness increases. An important R and D program is in progress to complement these results and to develop a SCC model for

  7. Laser-Beam Welding Impact on the Deformation Properties of Stainless Steels When Used for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Evin Emil

    2016-09-01

    Full Text Available Materials other than standard and advanced high strength steels are remarkable for the thin-walled structures of the car-body in recent years in order to safety enhancement, weight and emission reduction, corrosion resistance improvement. Thus, there are presented in the paper the deformation properties of laser welded austenitic AISI 304 and ferritic AISI 430 stainless steels compared to these one measured for the high strength low alloyed steel H220PD. The properties were researched by tensile test and 3-point bending test with fixed ends on specimens made of basic material and laser welded one. The specimens were welded by solid state fiber laser YLS-5000 in longitudinal direction (the load direction. The deformation properties such as strength, stiffness and deformation work were evaluated and compared. The strength and stiffness were calculated from tensile test results and the deformation work was calculated from both, tensile test and 3-point bending test results. There has been found only minor effect of laser welding to the deformation properties for high strength low alloyed steel H220PD and austenitic stainless steel AISI 304. Otherwise, the laser welding strongly influenced the deformation work of the ferritic stainless steel AISI 430 as well as the elongation at tensile test.

  8. Hot hardness characteristics of ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C, and Super Nitralloy

    Science.gov (United States)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1973-01-01

    Short-term hot hardness studies were performed with ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C (14-4-1) and case hardened Super Nitralloy. Hardness levels of each material were measured at elevated temperatures in an electric furnace with a low oxygen environment. Test temperatures ranged from 294 to 877 K. The hot hardness characteristics of the ausformed AISI-M-50, Matrix 2 WD-65, and modified AISI 440-C were the same as those determined for high-speed tool steels. Hot hardness for these steels can be predicted within one point Rockwell C. The hot hardness characteristics of both the case and core of Super Nitralloy were superior to AISI 52100 but inferior to the high-speed tool steels. The short-term Rockwell C hardness at temperature for the Super Nitralloy material between 294 and 769 K can be predicted within one point Rockwell C hardness.

  9. Tratamiento térmico del acero inoxidable ferrítico AISI 430L sinterizado en atmósfera de N2-H2

    Directory of Open Access Journals (Sweden)

    Ruiz-Prieto, J. M.

    2005-12-01

    Full Text Available In this Work the influence of sintering AISI 430L stainless steel in N2-H2 atmosphere on its properties and microstructure have been studied. The presence of nitrogen in the sintering atmosphere leads to complex nitrides formation the AISI 430L sintered steel microstructure. A subsequent heat treatment was applied to modify this microstructure in order to improve the mechanical properties and corrosion resistance of these ferritic stainless steels.Los aceros inoxidables ferríticos, son aceros que contienen esencialmente cromo (12-30 % junto con níquel y molibdeno en cantidades que, en general, no sobrepasan el 1 % y, en ocasiones, se les adicionan otros elementos como son el aluminio, silicio, titanio o niobio. En el presente trabajo de investigación se ha evaluado la influencia del nitrógeno presente en la atmósfera de sinterización sobre la microestructura y propiedades del acero inoxidable ferrítico AISI 430L. Además, se ha realizado un tratamiento térmico posterior de hipertemple y maduración con el objeto de incrementar las propiedades mecánicas y a corrosión de este acero inoxidable, mediante la modificación microestructural de los nitruros complejos de hierro y cromo precipitados durante la etapa de sinterización.

  10. Estimation of Fracture Length as a Mechanical Property in Hydrofraturing Technique using an Experimental Setup

    Directory of Open Access Journals (Sweden)

    B. Guruprasad

    2012-12-01

    Full Text Available This paper compares temperature distribution and weld bead profiles of constant current and pulsed current gas tungsten arc welded AISI 304L grade stainless steel joints. The effects of pulsed current welding on tensile properties, hardness profiles, micro structural features and residual stress distribution of stainless steel joints are reported. The use of pulsed current technique improves the tensile properties of the welds compared to those of continuous current welds due to grain refinement occurring in the fusion zone.

  11. Fatigue of stainless steel in hydrogen

    Science.gov (United States)

    Schuster, G.; Altstetter, C.

    1983-10-01

    The fatigue crack growth rates of two austenitic stainless steel alloys, AISI 301 and 302, were compared in air, argon, and hydrogen environments at atmospheric pressure and room temperature. Under the stresses at the crack tip the austenite in type 301 steel transformed martensitically to a’ to a greater extent than in type 302 steel. The steels were also tested in the cold worked condition under hydrogen or argon. Hydrogen was found to have a deleterious effect on both steels, but the effect was stronger in the unstable than in the stable alloy. Cold work decreased fatigue crack growth rates in argon and hydrogen, but the decrease was less marked in hydrogen than in argon. Metallographic, fractographic, and microhardness surveys in the vicinity of the fatigue crack were used to try to understand the reasons for the observed fatigue behavior.

  12. KINETICS OF α'-MARTENSITE FORMATION DURING FATIGUE DEFORMATION IN METASTABLE AUSTENITIC STAINLESS STEEL

    OpenAIRE

    Tsuzaki, K.; T. Maki; Tamura, I.

    1982-01-01

    The effect of applied total strain range on the critical condition necessary for the onset of α'-martensitic transformation kinetics during the fatigue deformation was studied in AISI type 304 metastable austenitic stainless steel at room temperature. In the case of fatigue deformation, the α'-martensite formation was observed even in the condition that the saturated stress amplitude of austenite phase is smaller than the critical applied stress for the onset of α'-martensite formation for th...

  13. Performance evaluation of vegetable-based oils in drilling austenitic stainless steel

    DEFF Research Database (Denmark)

    Belluco, Walter; De Chiffre, Leonardo

    2004-01-01

    The efficiency of six cutting oils was evaluated in drilling AISI 316L austenitic stainless steel using conventional HSS-Co tools by measurements of tool life, tool wear, cutting forces and chip formation. Seven tools were tested with each fluid to catastrophic failure. Cutting forces and chip...... in a measurement capability comparable to that obtained using tool life as a performance criterion. As a consequence, it is suggested that drilling thrust can be used to assess the performance of cutting fluids in drilling stainless steel, resulting in considerable time savings and cost reduction with respect...

  14. Hydrogen Silsesquioxane based silica glass coatings for the corrosion protection of austenitic stainless steel

    DEFF Research Database (Denmark)

    Lampert, Felix; Jensen, Annemette Hindhede; Din, Rameez Ud

    2016-01-01

    The application of stainless steels in hostile environments, such as concentrated acid or hot sea water, requires additional surface treatments, considering that the native surface oxide does not guarantee sufficient corrosion protection under these conditions. In the present work, silica-like thin......-film barrier coatings were deposited on AISI 316L grade austenitic stainless steel with 2B surface finish from Hydrogen Silsesquioxane (HSQ) spin-on-glass precursor and thermally cured to tailor the film properties. Results showed that curing at 500 °C resulted in a film-structure with a polymerized siloxane...

  15. The effect of grain size on the mechanical response of a metastable austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Sinclair C.W.

    2013-11-01

    Full Text Available The combination of high environmental resistance and excellent strength, elongation and energy absorption make austenitic stainless steels potentially attractive for transportation applications. In the case of metastable grades that undergo a strain induced martensitic transformation it is possible to significantly change the mechanical properties simply by changing the austenite grain size. Predicting such behaviour using physically based models is, however, extremely challenging. Here, some recent work on the coupling between grain size and mechanical response will be presented for a metastable AISI 301 LN stainless steel. Successes and continuing challenges will be highlighted.

  16. Nanosized controlled surface pretreatment of biometallic alloy 316L stainless steel.

    Science.gov (United States)

    Abdel-Fattah, Tarek M; Loftis, Derek; Mahapatro, Anil

    2011-12-01

    Stainless steel (AISI 316L) is a medical grade stainless steel alloy used extensively in medical devices and in the biomedical field. 316L stainless steel was successfully electropolished via an ecologically friendly and biocompatible ionic liquid (IL) medium based on Vitamin B4 (NB4) and resulting in nanosized surface roughness and topography. Voltammetry and chronoamperometry tests determined optimum polishing conditions for the stainless steel alloy while atomic force microscopy (AFM) and scanning electron microscopy (SEM) provided surface morphology comparisons to benchmark success of each electropolishing condition. Energy dispersive X-ray analysis (EDX) combined with SEM revealed significantly smoother surfaces for each alloy surface while indicating that the constituent metals comprising each alloy effectively electropolished at uniform rates.

  17. The effect of thermal annealing on the adherence of $Al_2O_3$-films deposited by low-pressure, metal-organic, chemical-vapor deposition on AISI 304

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Vendel, van de D.; Corbach, van H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin alumina films, deposited at 280°C by low-pressure, metal-organic, chemical-vapor deposition on stainless steel, type AISI 304, were annealed at 0.17 kPa in a nitrogen atmosphere for 2,4, and 17 hr at 600, 700, and 800°C. The effect of the annealing process on the adhesion of the thin alumina fi

  18. Surface treatment and corrosion behaviour of austenitic stainless steel biomaterial

    Science.gov (United States)

    Oravcová, M.; Palček, P.; Zatkalíková, V.; Tański, T.; Król, M.

    2017-02-01

    In this article results from corrosion behaviour of austenitic stainless steel AISI 316L after different surface treatments are published. “As received” surface and surface after grinding resulted in lower resistance to pitting corrosion in physiological solution than electrochemically polished in H3PO4+H2SO4+H2O. Electropolishing also improved the surface roughness in comparison with the “as received” surface. Deposition of Al2O3 nanometric ALD coating improves the corrosion resistance of stainless steel in chloride-containing environment by shifting the breakdown potential toward more positive values. This oxide coating not only improves the corrosion resistance but it also affects the wettability of the surface, resulting in hydrophobic surface.

  19. Study on Structure and Corrosion Resistance Analysis of Carburizing Organization of Austenitic Stainless Steel%奥氏体不锈钢渗碳层的组织及耐蚀强化性能研究

    Institute of Scientific and Technical Information of China (English)

    李朋; 潘邻; 张良界; 杨闽红; 朱云峰; 马飞; 王成虎

    2013-01-01

    针对常规渗碳工艺会削弱奥氏体不锈钢耐蚀性的问题,通过对现有气体渗碳技术进行改进,采用前处理活化、降低渗碳温度的方法,实现了奥氏体不锈钢渗碳兼顾表面强度与耐蚀性能的目标.采用该工艺对AISI304和AISI316奥氏体不锈钢进行渗碳处理,并分析渗层组织和性能,结果表明,在470℃条件下,AISI316不锈钢经气体渗碳处理后,渗碳层具有优异的耐蚀强化性能.%In view of the conventional carburization weakening austenitic stainless steel corrosion resistance problem,based on the existing gas carburizing technology was improved,using pretreatment activation,carburizing temperature reduction methods,realized the austenitic stainless steel carburized surface strength and corrosion resistant properties of the target.Using this process on AISI304,AISI316 austenitic stainless steel carburizing processing,and get the austenitic stainless steel for low temperature carburizing organization performance carries on the analysis and research,research shows that under the condition of 470 ℃,AISI316 stainless steel carburization treated by low temperature gas carburizing layer has excellent corrosion resistance improved performance.

  20. Comportamiento electroquímico de un acero inoxidable AISI 430 implantado con cerio

    Directory of Open Access Journals (Sweden)

    Abreu, C. M.

    2002-10-01

    Full Text Available Chemical treatment in solutions containing cerium compounds has been widely used for prevention of localized corrosion in aluminium alloys (pitting corrosion as well as in stainless steels (crevice corrosion. Ionic implantation presents several advantages for stainless steels. The present paper is devoted to study the effect of cerium implantation on the properties of passive films formed on an AISI 430 stainless steel in alkaline medium. The electrochemical study is performed by cyclic voltammetry and EIS. The chemical characterisation of the oxides film developed is performed by XPS, and the morphological study corresponds to SEM examination. The results show that cerium implantation hinders magnetite formation as well as chromium oxidation processes.

    En los últimos años, se ha extendido el uso de disoluciones de sales de cerio como tratamiento para mejorar la resistencia localizada de las aleaciones de aluminio y para incrementar la resistencia a la corrosión en resquicio de diversos aceros inoxidables. En el caso de estos últimos, la adición de cerio mediante implantación iónica supone notables ventajas con respecto a otros tratamientos. En este artículo se investiga el efecto que ejerce la implantación de cerio sobre la película pasivante de un acero inoxidable ferrítico AISI 430. Para ello, se analiza el comportamiento electroquímico en medio básico mediante la utilización de voltametría cíclica y espectroscopia de impedancia electroquímica. La caracterización química de la película de óxidos formada se realiza mediante XPS, y el estudio morfológico mediante SEM. Los resultados muestran una importante inhibición en la formación de magnetita, así como una reducción en el proceso de oxidación que experimenta el cromo en el acero implantado con cerio.

  1. Environmental crack-growth behavior of high strength pressure vessel alloys

    Science.gov (United States)

    Forman, R. G.

    1975-01-01

    Results of sustained-load environmental crack growth threshold tests performed on six spacecraft pressure vessel alloys are presented. The alloys were Inconel 718, 6Al-4V titanium, A-286 steel, AM-350 stainless steel, cryoformed AISI 301 stainless steel; and cryoformed AISI 304L steel. The test environments for the program were air, pressurized gases of hydrogen, oxygen, nitrogen, and carbon dioxide, and liquid environments of distilled water, sea water, nitrogen tetroxide, hydrazine, aerozine 50, monomethyl hydrazine, and hydrogen peroxide. Surface flaw type specimens were used with flaws located in both base metal and weld metal.

  2. Corrosion behavior of stainless steel in bio diesel production; Comportamento quanto a corrosao de acos inoxidaveis na producao do biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, E.F. de [ArcelorMittal Sao Paulo Servicos, SP (Brazil); Moreira, M.C.; Lebrao, S.M.G. [Centro Universitario do Instituto Maua de Tecnologia, Sao Paulo, SP (Brazil)], e-mail: susana.lebrao@maua.br

    2010-07-01

    Biodiesel has become more attractive due to the benefits to the environment, mainly because it is a renewable resource. However, the main barrier to biodiesel is it cost. One factor which is charged to marketing is the use of stainless steel throughout the production line, the most used is AISI 304. To evaluate more economical stainless steels, weight loss and stress corrosion tests were performed on samples of AISI 304 and 439 in methanol PS X30% sodium methylate solution, crude soybean oil, glycerol and biodiesel for about two hundred and fifty days. The mass loss was negligible, and there was complete absence of pitting and stress corrosion cracking in all media studied, showing that both alloys are suitable for the manufacture of such equipment. (author)

  3. Optimization of Friction Welding Process Parameters for Joining Carbon Steel and Stainless Steel%Optimization of Friction Welding Process Parameters for Joining Carbon Steel and Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    R Paventhan; P R Lakshminarayanan; V Balasubramanian

    2012-01-01

    Friction weIding is a solid state joining process used extensively currently owing to its advantages such as low heat input, high production efficiency, ease of manufacture, and environment friendliness. Materials difficult to be welded by fusion welding processes can be successfully welded by friction welding. An attempt was made to develop an empirical relationship to predict the tensile strength of friction welded AISI 1040 grade medium carbon steel and AISI 304 austenitic stainless steel, incorporating the process parameters such as friction pressure, forging pressure, friction time and forging time, which have great influence on strength of the joints. Response surface methodology was applied to optimize the friction welding process parameters to attain maximum tensile strength of the joint. The maximum tensile strength of 543 MPa could be obtained for the joints fabricated under the welding conditions of friction pressure of 90 MPa, forging pressure of 90 MPa, friction time of 6 s and forging time of 6 s.

  4. In vitro corrosion resistance of Lotus-type porous Ni-free stainless steels.

    Science.gov (United States)

    Alvarez, Kelly; Hyun, Soong-Keun; Fujimoto, Shinji; Nakajima, Hideo

    2008-11-01

    The corrosion behavior of three kinds of austenitic high nitrogen Lotus-type porous Ni-free stainless steels was examined in acellular simulated body fluid solutions and compared with type AISI 316L stainless steel. The corrosion resistance was evaluated by electrochemical techniques, the analysis of released metal ions was performed by inductively coupled plasma mass spectrometry (ICP-MS) and the cytotoxicity was investigated in a culture of murine osteoblasts cells. Total immunity to localized corrosion in simulated body fluid (SBF) solutions was exhibited by Lotus-type porous Ni-free stainless steels, while Lotus-type porous AISI 316L showed very low pitting corrosion resistance evidenced by pitting corrosion at a very low breakdown potential. Additionally, Lotus-type porous Ni-free stainless steels showed a quite low metal ion release in SBF solutions. Furthermore, cell culture studies showed that the fabricated materials were non-cytotoxic to mouse osteoblasts cell line. On the basis of these results, it can be concluded that the investigated alloys are biocompatible and corrosion resistant and a promising material for biomedical applications.

  5. Comparison of hydrogen gas embrittlement of austenitic and ferritic stainless steels

    Science.gov (United States)

    Perng, T. P.; Altstetter, C. J.

    1987-01-01

    Hydrogen-induced slow crack growth (SCG) was compared in austenitic and ferritic stainless steels at 0 to 125 °Cand 11 to 216 kPa of hydrogen gas. No SCG was observed for AISI 310, while AISI 301 was more susceptible to hydrogen embrittlement and had higher cracking velocity than AL 29-4-2 under the same test conditions. The kinetics of crack propagation was modeled in terms of the hydrogen transport in these alloys. This is a function of temperature, microstructure, and stress state in the embrittlement region. The relatively high cracking velocity of AISI 301 was shown to be controlled by the fast transport of hydrogen through the stress-induced α' martensite at the crack tip and low escape rate of hydrogen through the γ phase in the surrounding region. Faster accumulation rates of hydrogen in the embrittlement region were expected for AISI 301, which led to higher cracking velocities. The mechanism of hydrogen-induced SCG was discussed based upon the concept of hydrogen-enhanced plasticity.

  6. Graphene Nanoplatelets Based Protective and Functionalizing Coating for Stainless Steel.

    Science.gov (United States)

    Mondal, Jayanta; Kozlova, Jekaterina; Sammelselg, Väino

    2015-09-01

    Stainless steel is the most widely used alloy for many industrial and everyday applications, and protection of this alloy substrate against corrosion is an important industrial issue. Here we report a promising application of graphene oxide and graphene nanoplatelets as effective corrosion inhibitors for AISI type 304 stainless steel alloy. The graphene oxide and graphene coatings on the stainless steel substrates were prepared using spin coating techniques. Homogeneous and complete surface coverage by the graphene oxide and graphene nanoplatelets were observed with a high-resolution scanning electron microscope. The corrosion inhibition ability of these materials was investigated through measurement of open circuit potential and followed by potentiodymamic polarization analysis in aqueous sodium chloride solution before and after a month of immersion. Analyzed result exhibits effective corrosion inhibition for both substrates coated with graphene oxide or graphene nanoplatelets by increasing corrosion potential, pitting potential and decreasing passive current density. The corrosion inhibition ability of the coated substrates has not changed even after the long-term immersion. The result showed both graphene materials can be used as an effective corrosion inhibitor for the stainless steel substrates, which would certainly increase lifetime the substrate. However, long-term protection ability of the graphene coated susbtsrate showed somewhat better inhibition performance than the ones coated with graphene oxide.

  7. Effect of forming technique BixSiyOz coatings obtained by sol- gel and supported on 316L stainless steel

    Science.gov (United States)

    Bautista Ruiz, J.; Olaya Flórez, J.; Aperador, W.

    2016-02-01

    BixSiyOz type coatings via sol-gel synthesized from bismuth nitrate pentahydrate, and tetraethyl orthosilicate as precursors; glacial acetic acid and 2-ethoxyethanol as solvents, and ethanolamine as complexing. The coatings were supported on AISI 316L stainless steel substrate through dip-coating and spin-coating techniques. The study showed that the spin-coating technique is efficient than dip-coating because it allows more dense and homogeneous films.

  8. Stress-induced martensitic transformation in metastable austenitic stainless steels: Effect on fatigue crack growth rate

    Science.gov (United States)

    Khan, Z.; Ahmed, M.

    1996-04-01

    This paper addresses the influence of cyclic stress-induced martensitic transformation on fatigue crack growth rates in metastable austenitic stainless steels. At low applied stress and mean stress values in AISI type 301 stainless steel, fatigue crack growth rate is substantially retarded due to a cyclic stress-induced γ-α' and γ-ɛ martensitic transformation occurring at the crack-tip plastic zone. It is suggested that the transformation products produce a compressive residual stress at the tip of the fatigue crack, which essentially lowers the effective stress intensity and hence retards the fatigue crack growth rate. At high applied stress or mean stress values, fatigue crack growth rates in AISI type 301 steels become almost equal to those of stable AISI type 302 alloy. As the amount of transformed products increases (with an increase in applied or mean stress), the strain-hardening effect brought about by the transformed martensite phase appears to accelerate fatigue crack growth, offsetting the contribution from the compressive residual stress produced by the positive volume change of γ → α' or ɛ transformation.

  9. Improvement of mechanical properties on metastable stainless steels by reversion heat treatments

    Science.gov (United States)

    Mateo, A.; Zapata, A.; Fargas, G.

    2013-12-01

    AISI 301LN is a metastable austenitic stainless steel that offers an excellent combination of high strength and ductility. This stainless grade is currently used in applications where severe forming operations are required, such as automotive bodies. When these metastable steels are plastically deformed at room temperature, for example by cold rolling, austenite transforms to martensite and, as a result, yield strength increases but ductility is reduced. Grain refinement is the only method that allows improving strength and ductility simultaneously. Several researchers have demonstrated that fine grain AISI 301LN can be obtained by heat treatment after cold rolling. This heat treatment is called reversion because it provokes the reversion of strain induced martensite to austenite. In the present work, sheets of AISI 301LN previously subjected to 20% of cold rolling reduction were treated and a refined grain austenitic microstructure was obtained. Mechanical properties, including fatigue limit, were determined and compared with those corresponding to the steel both before and after the cold rolling.

  10. Fretting fatigue in AISI 1015 steel

    Indian Academy of Sciences (India)

    R Gnanamoorthy; R Rosi Reddy

    2002-04-01

    A small osillatory movement between two contacting surfaces is termed as fretting and on many occasions it acts as the crack initiation site leading to catastrophic failure of the overall structure. The occurrence of fretting is observed in many engineering structures such as shaft flanges, gas turbines, steel ropes etc. An experimental facility, which can simulate the fretting fatigue in many engineering applications, is the primary requirement of the research program. A laboratory fretting fatigue test facility capable of varying many influencing parameters of fretting fatigue such as slip amplitutde, frequency, contact pressure, etc is designed and developed. Preliminary investigations on plain and fretting fatigue behaviour of AISI 1015 structural steel are reported in this paper. A strength reduction factor of about 1.30 was obtained due to fretting for the test material under the present experimental conditions. Influence of contact load on fretting was also studied. Increasing fretting contact load decreased the fatigue life in the range investigated. Failure analysis showed typical stage I oblique crack growth followed by stage II straight crack perpedicular to the fretting zone.

  11. Contribution to the Study of Effects of Surface State of Welded Joints in Stainless Steel Upon Resistance Towards Pitting Corrosion

    Directory of Open Access Journals (Sweden)

    Juraga, I.

    2007-01-01

    Full Text Available Successful corrosion resistance of stainless steels is based on their natural ability of passivation, i.e. formation of film of chromium oxides that prevents corrosion in many environments. Any nonuniformity of surface layers may be initial spot for corrosion processes and damages. In this contribution, beside real corrosion damages occurred in practice, results of testing of pitting corrosion resistance of weld beads made applying TIG process on AISI 316L steel grade are presented. SEM and EDX testing, as well as electrochemical corrosion testing confirmed adverse effects of heat tints zones upon corrosion resistance of stainless steels.

  12. Influence of copper and tin addition on pitting corrosion behaviour of AISI 304 Strainless Steel; Efecto de la adicion de cobre y estano en el comportamiento a la corrosion por picadura de acero inoxidable AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M. C.; Botella, J.; Matres, V.; Viejo, F.; Carboneras, M.; Arrabal, R.

    2004-07-01

    The influence of copper and tin addition on the pitting corrosion resistance of AISI 304 stainless steel in 3.5% NaCl at 20 degree centigree has been studied using potenciodinamic and cyclic polarization. From that study the effect of alloying elements (Cu and Sn) in the corrosion, pitting and re passivation potentials were determined. The effect of copper and tin on the critical pitting temperature (CPT) was determined by i{sub c}orr-time-temperature curves. The influence of these alloying elements in FeCl{sub 3} under ASTM G48-00 norm was also studied. The addition of copper favours the nucleation of pits. The addition of tin slightly improves the corrosion resistance. The synergic effect of Cu-Sn was positive at low concentrations. (Author) 10 refs.

  13. The Gibbs Thomson effect in magnetron-sputtered austenitic stainless steel films

    Science.gov (United States)

    Cusenza, S.; Borchers, C.; Carpene, E.; Schaaf, P.

    2007-03-01

    Magnetron sputtering of austenitic stainless steel AISI 316, which has a face-centred cubic structure (γ), leads to films exhibiting a body-centred cubic (α) structure or a mixture of α- and γ-phases. The microstructure of the deposited films was studied by Mössbauer spectroscopy, x-ray diffraction and transmission electron microscopy. With increasing deposition temperature a phase transformation from α- to γ-phase was observed in these films. Instantaneous recording of the electromotive force shows that nickel content and deposition temperature are crucial factors for phase stability and phase formation. In room temperature deposited stainless steel films, the phase transformation after vacuum annealing can be described by the Johnson-Mehl-Avrami kinetic model. These phase transformations in stainless steel films during annealing can be explained with the Gibbs-Thomson effect, where the grain boundary energy raises the Gibbs free energy.

  14. The Gibbs-Thomson effect in magnetron-sputtered austenitic stainless steel films

    Energy Technology Data Exchange (ETDEWEB)

    Cusenza, S [Universitaet Goettingen, II Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Borchers, C [Universitaet Goettingen, II Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Carpene, E [Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci 32, 20133 Milan (Italy); Schaaf, P [Universitaet Goettingen, II Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)

    2007-03-14

    Magnetron sputtering of austenitic stainless steel AISI 316, which has a face-centred cubic structure ({gamma}), leads to films exhibiting a body-centred cubic ({alpha}) structure or a mixture of {alpha}- and {gamma}-phases. The microstructure of the deposited films was studied by Moessbauer spectroscopy, x-ray diffraction and transmission electron microscopy. With increasing deposition temperature a phase transformation from {alpha}- to {gamma}-phase was observed in these films. Instantaneous recording of the electromotive force shows that nickel content and deposition temperature are crucial factors for phase stability and phase formation. In room temperature deposited stainless steel films, the phase transformation after vacuum annealing can be described by the Johnson-Mehl-Avrami kinetic model. These phase transformations in stainless steel films during annealing can be explained with the Gibbs-Thomson effect, where the grain boundary energy raises the Gibbs free energy.

  15. Corrosion fatigue behaviour of 317LN austenitic stainless steel in phosphoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Onoro, J. [Ingenieria y Ciencia de los Materiales, ETSI Industriales, Universidad Politecnica de Madrid, c/Jose Gutierrez Abascal, 2, 28006 Madrid (Spain)], E-mail: javier.onoro@upm.es

    2009-10-15

    The corrosion fatigue crack-growth behaviour of AISI 317LN stainless steel was evaluated in air and in 85% phosphoric acid at 20 deg. C. Austenitic stainless steels with high molybdenum content have high corrosion resistance and good mechanical properties. However, this increase in the molybdenum content and other elements such as nitrogen can also modify the microstructure. This leads to a modification of its mechanical properties. The corrosion fatigue crack-growth rate was higher in phosphoric acid immersion than in air. Austenitic stainless steels with a fully austenitic microstructure were more ductile, tough, and behave better against corrosion fatigue. The higher resistance to corrosion fatigue was directly associated to its higher resistance to corrosion.

  16. Comparison of adhesion of the food spoilage bacterium Shewanella putrefaciens to stainless steel and silver surfaces

    DEFF Research Database (Denmark)

    Hjelm, Mette; Hilbert, Lisbeth Rischel; Møller, Per;

    2002-01-01

    (new silver, tarnished silver and sulphide treated silver) was compared to adhesion to stainless steel (AISI 316). Numbers of attached bacteria (cfu cm-2) were estimated using the Malthus indirect conductance method. A lower number of attached bacteria were measured on new silver surfaces compared...... to stainless steel for samples taken after 24 hours. However this was not significant (P > 0.05). The numbers of attached bacteria were consistently lower when tarnished silver surfaces were compared to stainless steel and some, but not all, experiments showed statistically significant. A difference of more...... than one log unit in bacterial numbers on the two types of materials was observed, but for most samples the difference was within one log unit. Treating new silver with sulphide to try to reproduce a tarnished silver surface did not result in a similar lowering of adhering cells when compared to steel...

  17. Reduction of liquid metal embrittlement in copper-brazed stainless steel joints

    Science.gov (United States)

    Uhlig, T.; Fedorov, V.; Elßner, M.; Wagner, G.; Weis, S.

    2017-03-01

    Due to its very good formability and the low raw material cost, pure copper in form of foils is commonly used to braze plate heat exchangers made of stainless steel. The difference in the electrochemical potentials of brazing filler and base material leads to corrosion effects in contact with electrolytes. This may lead to leakages, which decrease the reliability of the heat exchanger during service in potable water. The dissolution of the emerging corrosion products of brazing filler and base material induces the migration of heavy metal ions, such as Cu2+ and Ni2+, into the potable water. The so-called liquid metal embrittlement, which takes place during the brazing process, may intensify the corrosion. The brazing filler infiltrates the stainless steel along the grain boundaries and causes an embrittlement. This paper deals with the determination of the grain boundary erosion dependent on the degree of deformation and heat treatment of the stainless steel AISI 316L.

  18. Antibacterial Property of Martensitic Stainless Steel Generated by Cu Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    XU Bo-fan; NI Hong-wei; DAN Zhi-gang; XIONG Juan; XIONG Ping-yuan

    2004-01-01

    Copper ions were implanted into a AISI420 martensitic stainless steel (SS) by metal vapor vacuum arc (MEVVA) with a dose range 0.2 ×1017 ~5.0×1017 cm-2 at the energy of 100keV. The Cu-implanted stainless steel was treated by a special antibacterial treatment subsequently. The phase compositions in the implanted layer were studied by glancing X-ray diffraction (GXRD) and changes of bacterial appearance on the surface of Cu un-implanted SS and Cu-implanted SS with antibacterial treatment SS were observed by bio-TEM (transmission electron microscopy) separately. The results showed that a suitable amount of Cu-rich phase was dispersed in the implanted layer of Cu-implanted SS that was treated by special antibacterial treatment. So the Cu-implanted martensitic stainless steel with antibacterial treatment reveals excellent antibacterial property against both E. coli and S. aureus.

  19. Antibacterial Property of Martensitic Stainless Steel Generated by Cu Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    XUBo-fan; NIHong-wei; DANZhi-gang; XIONGJuan; XIONGPing-yuan

    2004-01-01

    Copper ions were implanted into a AISI420 martensitic stainless steel (SS) by metal vapor vacuum arc (MEVVA) with a dose range 0.2×1017-5.0×1017cm-2 at the energy of 100keV. The Cu-implanted stainless steel was treated by a special antibacterial treatment subsequently. The phase compositions in the implanted layer were studied by glancing X-ray diffraction (GXRD) and changes of bacterial appearance on the surface of Cu un-implanted SS and Cu-implanted SS with antibacterial treatment SS were observed by bio-TEM (transmission electron microscopy) separately. The results showed that a suitable amount of Cu-rich phase was dispersed in the implanted layer of Cu-implanted SS that was treated by special antibacterial treatment. So the Cu-implanted martensitic stainless steel with antibacterial treatment reveals excellent antibacterial property against both E. coli and S. aureus.

  20. Stress corrosion cracking of austenitic stainless steel core internal welds.

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Park, J.-H.; Ruther, W. E.; Sanecki, J. E.; Strain, R. V.; Zaluzec, N. J.

    1999-04-14

    Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that had cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L, as well as 304 SS core shroud welds and mockup shielded-metal-arc welds, were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on the grain boundaries. However, as a result of exposure to welding fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine, which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests also indicate that fluorine exacerbates the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of core shroud welds.

  1. Evaluación del comportamiento estructural y de resistencia a la corrosión de armaduras de acero inoxidable austenítico AISI 304 y dúplex AISI 2304 embebidas en morteros de cemento Pórtland

    Directory of Open Access Journals (Sweden)

    Medina, E.

    2012-12-01

    Full Text Available The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304 and duplex EN 1.4362 (AISI 2304 have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR, of reinforcements embedded in ordinary Portland cement (OPC mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure.

    Se ha evaluado el comportamiento mecánico y estructural de dos aceros inoxidables corrugados, el austenítico EN 1.4301 (AISI 304 y el dúplex EN 1.4362 (AISI 2304, y se han comparado con el tradicional acero al carbono B500SD. El estudio se ha realizado en tres niveles: a nivel de barra, de sección y de pieza. Las diferentes características mecánicas de los aceros inoxidables condicionan el comportamiento a nivel de sección y de pieza estructural. El estudio del comportamiento frente a la corrosión de los dos aceros inoxidables se ha realizado mediante mediciones electroquímicas monitorizando el potencial de corrosión y la resistencia de polarización de armaduras embebidas en probetas de mortero contaminado con diferentes concentraciones de cloruros durante un tiempo de exposición de un año. Ambos aceros inoxidables permanecen en estado pasivo en las probetas para todos los contenidos de cloruros.

  2. Arc discharge deposition of stainless steel coatings at different nitrogen pressures

    Energy Technology Data Exchange (ETDEWEB)

    Koskinen, J. [VTT Manufacturing Technology (Finland); Torri, P. [Helsinki Univ. (Finland). Dept. of Physics; Hirvonen, J.P. [VTT Manufacturing Technology (Finland); Mahiout, A. [VTT Manufacturing Technology (Finland); Stanishevsky, A. [Plasmoteg Engineering Centre, Minsk (Belarus)

    1996-03-01

    A filtered arc discharge process was employed to deposit stainless steel films using an AISI316 cathode. In this procedure, macroparticles and droplets, which are the most serious drawback of arc deposition processes especially in corrosion applications, are mostly filtered out. Films were deposited in vacuum or in the presence of a nitrogen plasma at different partial pressures. Low carbon steel and silicon single crystals were employed as substrates. Rutherford backscattering spectrometry (RBS), nuclear reaction analysis (NRA) and X-ray diffraction (XRD) were used to characterize the films. The corrosion properties were examined using electrochemical polarization measurements. The corrosion current density was clearly lower than that of bulk steel, but higher than that of bulk AISI316. Increasing the film thickness and nitrogen content lowered the corrosion current density. (orig.)

  3. Corrosion analysis of TP304L pipe used for ultra-supercritical boiler%超(超)临界火电机组用关键钢管TP304L腐蚀现象分析

    Institute of Scientific and Technical Information of China (English)

    李丹; 李冬升; 戴起勋; 王荣荣; 王国建; 刘瑜

    2013-01-01

    利用JSM-7001F扫描电子显微镜、Inca Energy350 X射线能谱仪等测试设备,对不合格的超(超)临界火电机组用TP304L钢管进行分析.结果表明,不合格的TP304L钢管内表面发生一定深度的腐蚀和沿晶腐蚀开裂.显微组织分析发现,管内表面晶界析出较多碳化物,而外表面很少,管心部组织也有少量碳化物.研究分析认为,出现沿晶腐蚀开裂和析出碳化物是由于在拉拔过程中发生高温快速渗碳的结果.%The unqualified TP304L pipes applied to ultra-supercritical thermal power units were analyzed by the JSM-7001F scanning electron microscope, Inca Energy350X energy spectrometer, etc. It is found a certain depth of corrosion occurred on the inside surface of the unqualified TP304L pipes in form of intergranular corrosion cracking. Microstructure analysis shows that there are more carbides precipitated at the grain boundaries on the inner surface of the pipes, and fewer on the outer surface or in the center of the pipes. It is considered that the intergranular corrosion cracking and carbide precipitation are due to high temperature and rapid carburizing during production.

  4. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    OpenAIRE

    Thanee Toomprasen; Chawalit Thinvongpituk; Sukangkana Talangkun

    2014-01-01

    This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grain...

  5. 2016 Accomplishments. Tritium aging studies on stainless steel. Forging process effects on the fracture toughness properties of tritium-precharged stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-01-01

    Forged austenitic stainless steels are used as the materials of construction for pressure vessels designed to contain tritium at high pressure. These steels are highly resistant to tritium-assisted fracture but their resistance can depend on the details of the forging microstructure. During FY16, the effects of forging strain rate and deformation temperature on the fracture toughness properties of tritium-exposed-and-aged Type 304L stainless steel were studied. Forgings were produced from a single heat of steel using four types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy-rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The objective of the study was to characterize the J-Integral fracture toughness properties as a function of the industrial strain rate and temperature. The second objective was to measure the effects of tritium and decay helium on toughness. Tritium and decay helium effects were measured by thermally precharging the as-forged specimens with tritium gas at 34.5 MPa and 350°C and aging for up to five years at -80°C to build-in decay helium prior to testing. The results of this study show that the fracture toughness properties of the as-forged steels vary with forging strain rate and forging temperature. The effect is largely due to yield strength as the higher-strength forgings had the lower toughness values. For non-charged specimens, fracture toughness properties were improved by forging at 871°C versus 816°C and Screw-Press forgings tended to have lower fracture toughness values than the other forgings. Tritium exposures reduced the fracture toughness values remarkably to fracture toughness values averaging 10-20% of as-forged values. However, forging strain rate and temperature had little or no effect on the fracture toughness after tritium precharging and aging. The result was confirmed by fractography which indicated that fracture modes

  6. EFECTO DEL PROCESO DE SOLDADURA POR ARCO SOBRE LA COMPOSICIÓN DE HUMOS PRODUCIDOS EN LA SOLDADURA DE UN ACERO

    OpenAIRE

    VERA ALVARADO, JORGE WILFREDO

    2009-01-01

    The intention of this study is to investigate the effect of the process of weld GMAW, GTAW and SMAW in the composition of smoke of stainless steel weld AISI 304 L. The experimental design allowed to obtain eight samples by test simultaneously, caught in fiber glass filters impregnated with dissolution of sodium hydroxide 1M. The analytical method allows determining present chromium compounds in weld smoke according to the oxidation state and solubility, using like instrumental technique the a...

  7. IMPACT OF NUCLEAR MATERIAL DISSOLUTION ON VESSEL CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Dunn, K.; Clifton, B.

    2012-10-01

    Different nuclear materials require different processing conditions. In order to maximize the dissolver vessel lifetime, corrosion testing was conducted for a range of chemistries and temperature used in fuel dissolution. Compositional ranges of elements regularly in the dissolver were evaluated for corrosion of 304L, the material of construction. Corrosion rates of AISI Type 304 stainless steel coupons, both welded and non-welded coupons, were calculated from measured weight losses and post-test concentrations of soluble Fe, Cr and Ni.

  8. Contributions to the Acoustic Emission Symposium (5th), Tokyo, Japan, 18-20 November 1980.

    Science.gov (United States)

    1980-10-01

    s - d~ .NLA. 00 Apr IV ~V)W 0 5 13 15 20 20 . 200 67;x 250 a50 0 Ig 0 -A 2 300 301 )73X .1-27?e. t7531 2001. 200 250 4130 50 1______________ IN 5C 0 1...alloys (stainless steels, AISI 304L and 316), we found that planar dislocation glide reduced the AE out- put. In Cu-Ni alloys, this effect appears to be

  9. Impact Tensile Testing of Stainless Steels at Various Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    D. K. Morton

    2008-03-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern (1 to 300 per second) are not well documented. However, research is being performed at the Idaho National Laboratory to quantify these characteristics. The work presented herein discusses tensile impact testing of dual-marked 304/304L and 316/316L stainless steel material specimens. Both base material and welded material specimens were tested at -20 oF, room temperature, 300 oF, and 600 oF conditions. Utilizing a drop weight impact test machine and 1/4-inch and 1/2-inch thick dog bone-shaped test specimens, a strain rate range of approximately 4 to 40 per second (depending on initial temperature conditions) was achieved. Factors were determined that reflect the amount of increased strain energy the material can absorb due to strain rate effects. Using the factors, elevated true stress-strain curves for these materials at various strain rates and temperatures were generated. By incorporating the strain rate elevated true stress-strain material curves into an inelastic finite element computer program as the defined material input, significant improvement in the accuracy of the computer analyses was attained. However, additional impact testing is necessary to achieve higher strain rates (up to 300 per second) before complete definition of strain rate effects can be made for accidental drop events and other similar energy-limited impulsive loads. This research approach, using impact testing and a total energy analysis methodology to quantify strain rate effects, can be applied to many other materials used in government and industry.

  10. Biofilm formation by Listeria monocytogenes on stainless steel surface and biotransfer potential

    Directory of Open Access Journals (Sweden)

    Maíra Maciel Mattos de Oliveira

    2010-03-01

    Full Text Available An experimental model was proposed to study biofilm formation by Listeria monocytogenes ATCC 19117 on AISI 304 (#4 stainless steel surface and biotransfer potential during this process. In this model, biofilm formation was conducted on the surface of stainless steel coupons, set on a stainless steel base with 4 divisions, each one supporting 21 coupons. Trypic Soy Broth was used as bacterial growth substrate, with incubation at 37 ºC and stirring of 50 rpm. The number of adhered cells was determined after 3, 48, 96, 144, 192 and 240 hours of biofilm formation and biotransfer potential from 96 hours. Stainless steel coupons were submitted to Scanning Electron Microscopy (SEM after 3, 144 and 240 hours. Based on the number of adhered cells and SEM, it was observed that L. monocytogenes adhered rapidly to the stainless steel surface, with mature biofilm being formed after 240 hours. The biotransfer potential of bacterium to substrate occurred at all the stages analyzed. The rapid capacity of adhesion to surface, combined with biotransfer potential throughout the biofilm formation stages, make L. monocytogenes a potential risk to the food industry. Both the experimental model developed and the methodology used were efficient in the study of biofilm formation by L. monocytogenes on stainless steel surface and biotransfer potential.

  11. Performance optimization of water-jet assisted underwater laser cutting of AISI 304 stainless steel sheet

    Science.gov (United States)

    Mullick, Suvradip; Madhukar, Yuvraj K.; Roy, Subhransu; Nath, Ashish K.

    2016-08-01

    Recent development of water-jet assisted underwater laser cutting has shown some advantages over the gas assisted underwater laser cutting, as it produces much less turbulence, gas bubble and aerosols, resulting in a more gentle process. However, this process has relatively low efficiency due to different losses in water. Scattering is reported to be a dominant loss mechanism, which depends on the growth of vapor layer at cut front and its removal by water-jet. Present study reports improvement in process efficiency by reducing the scattering loss using modulated laser power. Judicious control of laser pulse on- and off-time could improve process efficiency through restricting the vapor growth and its effective removal by water-jet within the laser on- and off-time, respectively. Effects of average laser power, duty cycle and modulation frequency on specific energy are studied to get an operating zone for maximum efficiency. Next, the variation in laser cut quality with different process parameters are studied within this operating zone using Design of experiment (DOE). Response surface methodology (RSM) is used by implementing three level Box-Behnken design to optimize the variation in cut quality, and to find out the optimal process parameters for desired quality. Various phenomena and material removal mechanism involved in this process are also discussed.

  12. Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Łępicka Magdalena

    2014-09-01

    Full Text Available Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18 stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively in two different temperature ranges (380 or 450°C specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

  13. The Effect of Welding Current and Composition of Stainless steel on the Panetration in GTAW

    Directory of Open Access Journals (Sweden)

    Ramazan Yılmaz

    2012-06-01

    Full Text Available In this study, welding was performed on the plates of two different types of AISI 316 and AISI 316Ti austenitic stainless steels by GTAW (Gas Tungsten Arc Welding without using welding consumable in flat position. Automatic GTAW welding machine was used to control and obtain the exact values. The effects of welding currents used in welding process and the compositions of the stainless steels materials on the penetration were investigated. Weld bead size and shape such as bead width and dept were important considerations for penetration. Welding process was performed using various welding current values. The study showed that both welding parameters and composition of the stainless steels has influence on the penetration and It is increased with increasing of welding current. Besides, P/W rate of the weldments were influenced by the current and hardness values of the weld metal decrease with increasing welding current. The microstructure of the weld metal was also changed by variation of welding current.

  14. Effects of high-pressure hydrogen charging on the structure of austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hoelzel, M. [Institute for Materials Science, Darmstadt University of Technology, Petersenstrasse 23, 64287 Darmstadt (Germany)]. E-mail: Markus.Hoelzel@frm2.tum.de; Danilkin, S.A. [Hahn-Meitner-Institut, SF2, Glienicker Str. 100, 14109 Berlin (Germany); Ehrenberg, H. [Institute for Materials Science, Darmstadt University of Technology, Petersenstrasse 23, 64287 Darmstadt (Germany); Toebbens, D.M. [Hahn-Meitner-Institut, SF2, Glienicker Str. 100, 14109 Berlin (Germany); Udovic, T.J. [NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, MS 8562, Gaithersburg, MD 20899-8562 (United States); Fuess, H. [Institute for Materials Science, Darmstadt University of Technology, Petersenstrasse 23, 64287 Darmstadt (Germany); Wipf, H. [Darmstadt University of Technology, Institute for Solid State Physics, Hochschulstrasse 6, 64289 Darmstadt (Germany)

    2004-10-25

    The effects of high-pressure hydrogen and deuterium charging on the structure of AISI type 304 and AISI type 310 austenitic stainless steels have been investigated by neutron and X-ray diffraction. Rietveld analyses of the neutron diffraction data revealed that hydrogen atoms occupy exclusively the octahedral interstitial sites in both steels. No phase transformations have been observed in 310 stainless steel within the whole range of hydrogen-to-metal atomic ratios H/Me up to {approx} 1. In 304 stainless steel, the formation of {epsilon}-martensite was observed not only after hydrogenation at 3.0 GPa (H/Me = 0.56), but also after applying a pressure of 4.0 GPa without hydrogen. The results differ significantly from published studies on cathodically hydrogenated samples, where high amounts of {epsilon}-martensite were observed in both steels. High-pressure hydrogenation and cathodic hydrogen charging result in different phase transformation behaviour. The discrepancies can be explained by different hydrogen distributions resulting in quite different stress states.

  15. Effect of Beam Oscillation on Microstructure and Mechanical Properties of AISI 316L Electron Beam Welds

    Science.gov (United States)

    Kar, Jyotirmaya; Roy, Sanat Kumar; Roy, Gour Gopal

    2017-04-01

    The properties of electron beam-welded AISI 316L stainless steel butt joints prepared with and without beam oscillation were evaluated by microstructural analysis, mechanical testing like microhardness measurements, tensile tests at room and elevated temperature 973 K (700 °C), three-point bend, and Charpy impact tests. All joints, irrespective of being prepared with or without beam oscillation, were found to be defect free. Welds produced by beam oscillation exhibited narrower fusion zone (FZ) with lathy ferrite morphology, while the weld without beam oscillation was characterized by wider FZ and skeletal ferrite morphology. During tensile tests at room and elevated temperature 973 K (700 °C), all samples fractured in the base metal (BM) and showed almost the same tensile properties as that of the BM. However, the notch tensile tests at room temperature demonstrated higher strength for joints prepared with the oscillating beam. Besides, face and root bend tests, as well as Charpy impact tests, showed higher bending strength and notch toughness, respectively, for joints prepared with beam oscillation.

  16. Effect of Beam Oscillation on Microstructure and Mechanical Properties of AISI 316L Electron Beam Welds

    Science.gov (United States)

    Kar, Jyotirmaya; Roy, Sanat Kumar; Roy, Gour Gopal

    2017-02-01

    The properties of electron beam-welded AISI 316L stainless steel butt joints prepared with and without beam oscillation were evaluated by microstructural analysis, mechanical testing like microhardness measurements, tensile tests at room and elevated temperature 973 K (700 °C), three-point bend, and Charpy impact tests. All joints, irrespective of being prepared with or without beam oscillation, were found to be defect free. Welds produced by beam oscillation exhibited narrower fusion zone (FZ) with lathy ferrite morphology, while the weld without beam oscillation was characterized by wider FZ and skeletal ferrite morphology. During tensile tests at room and elevated temperature 973 K (700 °C), all samples fractured in the base metal (BM) and showed almost the same tensile properties as that of the BM. However, the notch tensile tests at room temperature demonstrated higher strength for joints prepared with the oscillating beam. Besides, face and root bend tests, as well as Charpy impact tests, showed higher bending strength and notch toughness, respectively, for joints prepared with beam oscillation.

  17. Surface severe plastic deformation of AISI 304 via conventional shot peening, severe shot peening and repeening

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Okan, E-mail: unalokan78@gmail.com [Mechanical Engineering Department, Bartın University, Bartın 74100 (Turkey); Varol, Remzi [Mechanical Engineering Department, Suleyman Demirel University, Isparta 32200 (Turkey)

    2015-10-01

    Highlights: • CSP and SSP treatments transform austenite to metastable martensite structure. • Nanograin layer thickness after CSP and SSP is 8 μm and 22 μm, respectively. • Shot peening leads to carbon segregation from coarse to nano grain layer. • Repeening is an effective way to reduce surface roughness. - Abstract: Air blast conventional shot peening (CSP), severe shot peening (SSP) and repeening (RP) as a severe plastic deformation applications on AISI 304 austenitic stainless steel is addressed. Shot peened specimens are investigated based on optical, FESEM and digital microscope. The investigations present the austenite transformation to metastable martensite via mechanical twinning due to plastic deformation with high strain rates. It is found that SSP induces thicker nanograin layer with compared to CSP. In XRD studies, the austenite peaks broaden by means of severe shot peening and FWHM increase reveals the grain size reduction below 25 nm regimes on the surface. In EDAX line analysis of CSP specimen, carbon content increase has been detected from deformed layer through the nanocrystalline layer then the content reduces. The carbon segregation takes place due to the energy level distinction between dislocations and Fe−C bonds. 3d contour digital microscope studies and roughness investigations reveal that SSP has deleterious side effect on the surface roughness and surface flatness. However, RP is an effective way to reduce the surface roughness to reasonable values.

  18. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    Directory of Open Access Journals (Sweden)

    Thanee Toomprasen

    2014-06-01

    Full Text Available This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grains. in the welded area. This is the result of friction pressure and upset pressure in the welding process. In addition, the observation result indicated some changes of Ferrite and Pearlite in welded zone. This phase change resulted in the increment of hardness in AISI 4140 at the contact area and adjacent. In part of AISI 1040, the portion of Pearlite and Ferrite are not significantly changed, therefore the value of hardness is almost constant.

  19. Influence of oil and water media on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel

    Institute of Scientific and Technical Information of China (English)

    REN Ping-di; CHEN Guang-xiong; ZHU Min-hao; ZHOU Zhong-rong

    2004-01-01

    A series of fretting test were carried out using a DELTA PLINT testing system to study the influence of hydraulic oil and water on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel. The test result shows that media hydraulic oil and water have a distinct influence on fretting behaviour of the tested materials. Medium water can lead to shifting of the partial slip regime in the fretting map from a larger displacement amplitude toward a smaller one and enlargement of the mixed slip regime, in comparison with that in ambient atmosphere. While medium hydraulic oil can result in shifting of the partial slip regime from a smaller displacement amplitude toward a larger one. In the gross slip regime, hydraulic oil and water play a positive role as lubrication media. They can clearly decrease the fretting friction coefficient between AISI 52100 and AISI 1045. The test result also demonstrates that this lubrication effect will get better with increasing displacement amplitude and that hydraulic oil is better than water for lubrication. SEM observation of the wear scars displays that the fretting wear mainly results from abrasive wear and delamination of the fretted materials when using these two kinds of substances as lubrication media.

  20. Investigations on structure–property relationships of activated flux TIG weldments of super-duplex/austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Devendranath Ramkumar, K., E-mail: ramdevendranath@gmail.com; Bajpai, Ankur; Raghuvanshi, Shubham; Singh, Anshuman; Chandrasekhar, Aditya; Arivarasu, M.; Arivazhagan, N.

    2015-06-25

    This research work articulated the effect of SiO{sub 2} flux assisted tungsten inert gas (TIG) welding on the microstructure and mechanical properties of marine grade stainless steel weldments, such as super-duplex stainless steel (UNS S32750) and austenitic stainless steel (AISI 316L). The studies showed that the use of flux decreased the heat input required to obtain complete penetration. Microstructure studies revealed the presence of ferrite at the heat affected zone of AISI 316L and the fusion zone which obviated the hot cracking tendency. Tensile studies corroborated that the joint strength was sufficiently greater than that of the parent metals. Impact toughness slightly impoverished owing to the presence of large platelets of Widmanstätten austenite in the fusion zone. The study also explored the structure–property relationships of the flux assisted weldments using the combined techniques of optical and scanning electron microscopy analysis. Owing to the better metallurgical and mechanical properties, this study recommends the use of SiO{sub 2} flux for joining the dissimilar metals involving austenitic and super-duplex stainless steels.

  1. Study of the S phase structure on the AISI 316L steel by X-ray diffraction and Moessbauer spectroscopy; Estudo da estrutura da fase S no aco AISI 316L por difracao de raios X e espectroscopia Moessbauer

    Energy Technology Data Exchange (ETDEWEB)

    Gontijo, L.C. [Centro Federal de Educacao Tecnologica do Espirito Santo, Vitoria, ES (Brazil). Coordenadoria de Ciencia e Tecnologia; Machado, R.; Nascente, P.A.P. [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Engenharia de Materiais]. E-mail: nascente@power.ufscar.br; Miola, E.J. [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Fisica; Casteletti, L.C. [Universidade de Sao Paulo, Sao Carlos, SP (Brazil). Dept. de Engenharia de Materiais, Aeronautica e Automobilistica

    2005-07-01

    The plasma-nitriding technology has been employed in the industry with the objective of improving the surface properties of metals and alloys. By using the conventional nitriding process at low temperature, some of the properties of the austenitic stainless steels are enhanced by the formation of the S phase, also called expanded austenite. This phase is formed on the surfaces of the austenitic stainless steels nitrided under certain conditions. In the past years, an extensive research has been carried out for the understanding of the S phase, but some questions remain with no answer or with contradictory explanations. In this work, the AISI 316L steel was plasma-nitrided at 350 and 400 deg C, and the samples were characterized by X-ray diffraction (XRD) and conversion electron Moessbauer spectroscopy (CEMS) in order to investigate the S phase. XRD analysis identified the presence of a distorted cubic structure phase. The layer consists of a distribution of nitrogen austenite with different content of nitrogen, ranging from approximately 10 to 40 at-%, and also {gamma}-Fe{sub 4}N and {epsilon}-Fe{sub 2-3}N phases. Moessbauer spectroscopy corroborates these results, and shows a decrease in nitrogen austenite with the increase in nitriding temperature. This decrease is related to the transformation of the nitrogen austenite to the {gamma}-Fe{sub 4}N phase. (author)

  2. Low pressure powder injection moulding of stainless steel powders

    Energy Technology Data Exchange (ETDEWEB)

    Zampieron, J.V.; Soares, J.P.; Mathias, F.; Rossi, J.L. [Powder Processing Center CCP, Inst. de Pesquisas Energeticas e Nucleares, Sao Paulo, SP (Brazil); Filho, F.A. [IPEN, Inst. de Pesquisas Energeticas e Nucleares, Cidade Univ., Sao Paulo, SP (Brazil)

    2001-07-01

    Low-pressure powder injection moulding was used to obtain AISI 316L stainless steel parts. A rheological study was undertaken using gas-atomised powders and binders. The binders used were based on carnauba wax, paraffin, low density polyethylene and microcrystalline wax. The metal powders were characterised in terms of morphology, particle size distribution and specific surface area. These results were correlated to the rheological behaviour. The mixture was injected in the shape of square bar specimens to evaluate the performance of the injection process in the green state, and after sintering. The parameters such as injection pressure, viscosity and temperature were analysed for process optimisation. The binders were thermally removed in low vacuum with the assistance of alumina powders. Debinding and sintering were performed in a single step. This procedure shortened considerably the debinding and sintering time. (orig.)

  3. Nanoscaled periodic surface structures of medical stainless steel and their effect on osteoblast cells.

    Science.gov (United States)

    Elter, Patrick; Sickel, Franka; Ewald, Andrea

    2009-06-01

    Nanoscaled lamellar surface structures have been prepared on medical stainless steel AISI 316LVM surfaces by chemical etching of the decomposed phases. The effect of this structure on osteoblastic cells has been investigated. Long filopodia were developed by the cells perpendicular to the lamellar structure while almost no or only short filopodia were formed parallel to the lamellae. These results are explained in terms of a topographical influence of the nanostructure. During the growth process of the filopodia a nearly flat surface was recognized parallel to the lamellae while a topographical change was sensed perpendicular to the structure, which was preferred by the cells.

  4. On the Notch Effect in Low Temperature Carburized Stainless Steel under Fatigue

    Directory of Open Access Journals (Sweden)

    Minak G.

    2010-06-01

    Full Text Available The present paper describes the fatigue behaviour of carburized notched AISI 316 austenitic stainless steel specimens. Rotary four point bending fatigue tests have been performed using carburized smooth specimens with two different values of surface rugosity and notched specimen with two different stress concentration factors Kt, of 3.55 and 6.50 and the effects of carburizing on fatigue strength and notch sensitivity were discussed. Results show a general improvement of the fatigue life due to the treatment for all the series with an apparent notch sensitivity lower than one in the case of blunt notches due to secondary effects that were singled out.

  5. On the Notch Effect in Low Temperature Carburized Stainless Steel under Fatigue

    Science.gov (United States)

    Minak, G.

    2010-06-01

    The present paper describes the fatigue behaviour of carburized notched AISI 316 austenitic stainless steel specimens. Rotary four point bending fatigue tests have been performed using carburized smooth specimens with two different values of surface rugosity and notched specimen with two different stress concentration factors Kt, of 3.55 and 6.50 and the effects of carburizing on fatigue strength and notch sensitivity were discussed. Results show a general improvement of the fatigue life due to the treatment for all the series with an apparent notch sensitivity lower than one in the case of blunt notches due to secondary effects that were singled out.

  6. Effect of shot blasting on processoxidised stainless steel – morphology,chemistry and pickling performance

    OpenAIRE

    Myrsell, Johan

    2014-01-01

    The oxide scale created during manufacturing of stainless steel is often removed by a chemical pickling with mixed acid. Various pre-treatments to pickling are also applied to increase the efficiency of the oxide scale removal. Shot blasting is one such pre-treatment, which operates to remove a certain amount of oxide and also to generate cracks and openings for the subsequent pickling. In this work, three materials, AISI 2205, 430 and 304 have been blasted and later exposed to mixed acid. Th...

  7. Thermal stability study for candidate stainless steels of GEN IV reactors

    Science.gov (United States)

    Simeg Veternikova, J.; Degmova, J.; Pekarcikova, M.; Simko, F.; Petriska, M.; Skarba, M.; Mikula, P.; Pupala, M.

    2016-11-01

    Candidate stainless steels for GEN IV reactors were investigated in term of thermal and corrosion stability at high temperatures. New austenitic steel (NF 709), austenitic ODS steel (ODS 316) and two ferritic ODS steels (MA 956 and MA 957) were exposed to around 1000 °C in inert argon atmosphere at pressure of ∼8 MPa. The steels were further studied in a light of vacancy defects presence by positron annihilation spectroscopy and their thermal resistance was confronted to classic AISI steels. The thermal strain supported a creation of oxide layers observed by scanning electron microscopy (SEM).

  8. The Formation of Multipoles during the High-Temperature Creep of Austenitic Stainless Steels

    DEFF Research Database (Denmark)

    Howell, J.; Nielsson, O.; Horsewell, Andy

    1981-01-01

    It is shown that multipole dislocation configurations can arise during power-law creep of certain austenitic stainless steels. These multipoles have been analysed in some detail for two particular steels (Alloy 800 and a modified AISI 316L) and it is suggested that they arise either during...... instantaneous loading or during the primary creep stage. Trace analysis has shown that the multipoles are confined to {1 1 1} planes during primary creep but are not necessarily confined to these planes during steady-state creep unless they are pinned by interstitials....

  9. Recrystallization of niobium stabilized ferritic stainless steel during hot rolling simulation by torsion tests

    Directory of Open Access Journals (Sweden)

    Flávia Vieira Braga

    2016-01-01

    Full Text Available The aim of this study was to investigate the effect of finishing hot rolling temperature in promoting interpass recrystallization on a Nb-stabilized AISI 430 ferritic stainless steel. Torsion tests were performed in order to simulate the Steckel mill rolling process by varying the temperature ranges of the finishing passes. Interrupted torsion test were also performed and interpass recrystallization was evaluated via optical microscopy and electron backscatter diffraction (EBSD. As a result of this work, it has been established, within the restrictions of a Steckel mill rolling schedule, which thermomechanical conditions mostly favor SRX.

  10. A Plasma Control and Gas Protection System for Laser Welding of Stainless Steel

    DEFF Research Database (Denmark)

    Juhl, Thomas Winther; Olsen, Flemming Ove

    1997-01-01

    A prototype shield gas box with different plasma control nozzles have been investigated for laser welding of stainless steel (AISI 316). Different gases for plasma control and gas protection of the weld seam have been used. The gas types, welding speed and gas flows show the impact on process...... stability and protection against oxidation. Also oxidation related to special conditions at the starting edge has been investigated. The interaction between coaxial and plasma gas flow show that the coaxial flow widens the band in which the plasma gas flow suppresses the metal plasma. In this band the welds...

  11. Analysis of the elements sputtered during the lanthanum implantation in stainless steels

    Science.gov (United States)

    Ager, F. J.; Respaldiza, M. A.; Paúl, A.; Odriozola, J. A.; Lobato, J. M.; da Silva, M. F.; Redondo, L. M.; Soares, J. C.

    1998-04-01

    The evidence of the modification of the surface structure of the AISI-304 stainless steel during the implantation of lanthanum makes the analysis of the sputtered elements very interesting. Those sputtered elements are deposited on a carbon sheet placed in front of the steel being implanted, and studied by means of RBS and PIXE, together with the implanted specimens. Besides, the protective effect of the implanted ions during the high temperature oxidation is also studied by those techniques together with XRD and thermogravimetric methods.

  12. Analysis of the elements sputtered during the lanthanum implantation in stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Ager, F.J.; Respaldiza, M.A. [Sevilla Univ. (Spain). Dept. de FAMN; Paul, A.; Odriozola, J.A.; Lobato, J.M. [ICMSE, Universidad de Sevilla-CSIC, P.O. Pox 874, 41071 Sevilla (Spain); Silva, M.F. da; Redondo, L.M. [ITN, E.N. 10, 2685 Sacavem (Portugal); Soares, J.C. [CFNUL, Av. Prof. Gama Pinto 2, 1699 Lisboa Codex (Portugal)

    1998-04-01

    The evidence of the modification of the surface structure of the AISI-304 stainless steel during the implantation of lanthanum makes the analysis of the sputtered elements very interesting. Those sputtered elements are deposited on a carbon sheet placed in front of the steel being implanted, and studied by means of RBS and PIXE, together with the implanted specimens. Besides, the protective effect of the implanted ions during the high temperature oxidation is also studied by those techniques together with XRD and thermogravimetric methods. (orig.) 7 refs.

  13. Estimation of the kinetics of martensitic transformation in austenitic stainless steels by conventional and novel approaches

    Energy Technology Data Exchange (ETDEWEB)

    Shirdel, M., E-mail: mshirdel1989@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Mirzadeh, H., E-mail: hmirzadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Parsa, M.H., E-mail: mhparsa@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2015-01-29

    A comparative study was carried out on the kinetics of the martensitic transformation in a 304L stainless steel during cold rolling by conventional and novel approaches. The phase analysis based on X-ray diffraction patterns and metallography and also magnetic measurements based on ferritescope readings were utilized to elucidate the kinetics of the martensitic transformation. A straightforward magnetic measurement approach for evaluating the amount of strain-induced martensite in metastable austenitic stainless steels has been introduced in this study. This technique collects the data throughout the bulk of the material to give a realistic estimate of the amount of ferromagnetic martensite. This is an advantage over the surface collecting methods such as ferritescope readings, which overestimates the amount of martensite due to its inhomogeneous distribution through the thickness based on the frictional effects between the rolls and the specimen surface. The proposed approach can be applied in various designs for static/continuous magnetic measurement of bulk materials that is advantageous compared with the conventional vibrating sample magnetometer technique which is useful for static measurement of bulk materials with specific shapes. Moreover, in analogy to ferritescope, the output data of the developed device is directly related to the amount of martensite.

  14. Estudio de la influencia microbiológica en la corrosión de latones (UNS C68700, UNS C443 y acero inoxidable AISI 316;

    Directory of Open Access Journals (Sweden)

    Ohanian, Mauricio

    2014-06-01

    Full Text Available Microorganisms may play an important role in the corrosion process and generate conditions which affect the rate and/or the mechanism of deterioration. They become visible by the formation of biofilms: clusters of microorganisms and extracellular polymers. These biofilms affect not only the durability of the material, but also reduce the heat transfer. The present work studied the growth of aerobic and anaerobic heterotrophic microorganisms and sulfate reducing bacteria on aluminum brass (UNS C68700, admiralty brass (UNS C443 and stainless steel AISI 316 in exposure experiments held in the Bay of Montevideo (Uruguay. The influence of the biofilm growth on the corrosion behavior was studied by electrochemical techniques: polarization curves and Electrochemical Impedance Spectroscopy (EIS. The selection of the most suitable material for the exposure conditions is discussed and hypotheses of the corrosion mechanism are presented. Although stainless steel AISI 316 presented the lowest corrosion rate it showed localized deterioration.Los microorganismos influyen de manera significativa en el proceso corrosivo y generan condiciones que afectan la velocidad y/o el mecanismo de deterioro. Su presencia se manifiesta por la formación de bio-películas: conglomerados de bacterias y polímeros extracelulares. Dichas bio-películas afectan la durabilidad del material, la velocidad de flujo y la transferencia de calor. En el presente trabajo se evalúa el crecimiento de microorganismos heterótrofos aerobios, heterótrofos anaerobios y bacterias sulfato-reductoras sobre latón aluminio (UNS C68700, latón almirantazgo (UNS C443 y acero inoxidable AISI 316. Asimismo, se estudia la influencia del crecimiento de la bio-película sobre el comportamiento corrosivo mediante técnicas electroquímicas: curvas de polarización y espectroscopia de impedancia electroquímica. Las exposiciones se realizan en la Bahía de Montevideo, estuario del Río de la Plata

  15. Tribological and corrosion behaviors of carburized AISI 4340 steel

    Science.gov (United States)

    Thong-on, Atcharawadi; Boonruang, Chatdanai

    2016-01-01

    AISI 4340 steel is widely used in automotive and aircraft industries as gear components. In such applications, surface hardening processes such as carburizing are required in order to improve the life time of the components. There are many studies showing the tribological behavior of the carburized steel, but the corrosion behavior has not yet been clarified. This paper reports on both tribological and corrosion behaviors of the carburized AISI 4340 steel. Factor associated with carburizing, such as the quantities of deposited carbon, dissolved carbon, and formed Cr23C6 and Fe3C, affect the tribological and corrosion behaviors of the steel by improving hardness, friction, lubrication, and wear resistance; but corrosion resistance is reduced. The dissolved carbon affects the formation of the oxide layer of the carburized steel, by obstructing the continuous oxide layer formation and by decreasing the chromium content of the steel, leading to the decrease in the corrosion resistance of the steel.

  16. Magnetic Barkhausen emission in lightly deformed AISI 1070 steel

    Energy Technology Data Exchange (ETDEWEB)

    Capo Sanchez, J., E-mail: jcapo@cnt.uo.edu.cu [Departamento de Fisica, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n, 90500 Santiago de Cuba (Cuba); Campos, M.F. de [EEIMVR-Universidade Federal Fluminense, Av. dos Trabalhadores 420, Vila Santa Cecilia, 27255-125 Volta Redonda, RJ (Brazil); Padovese, L.R. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, Av. Prof. Mello Moraes, 2231, 05508-900 Sao Paulo (Brazil)

    2012-01-15

    The Magnetic Barkhausen Noise (MBN) technique can evaluate both micro- and macro-residual stresses, and provides indication about the relevance of contribution of these different stress components. MBN measurements were performed in AISI 1070 steel sheet samples, where different strains were applied. The Barkhausen emission is also analyzed when two different sheets, deformed and non-deformed, are evaluated together. This study is useful to understand the effect of a deformed region near the surface on MBN. The low permeability of the deformed region affects MBN, and if the deformed region is below the surface the magnetic Barkhausen signal increases. - Highlights: > Evaluated residual stresses by the magnetic Barkhausen technique. > Indication about the relevance of micro-and macro-stress components. > Magnetic Barkhausen measurements were carried out in AISI 1070 steel sheet samples. > Two different sheets, deformed and non-deformed, are evaluated together. > Magnetic Barkhausen signal increases when deformed region is below the surface.

  17. Laser surface hardening of AISI H13 tool steel

    Institute of Scientific and Technical Information of China (English)

    Jae-Ho LEE; Jeong-Hwan JANG; Byeong-Don JOO; Young-Myung SON; Young-Hoon MOON

    2009-01-01

    An attempt was made to improve the surface hardness and wear properties of AISI H13 tool steel through solid solution hardening and refinement of microstructures using a 200 W fiber laser as a heat generating source. The hardness of laser melted zone was investigated. In order to identify the effect of heat input on the laser melting zone, scanning conditions were controlled. The results show that, the hardness of as-received AISI H13 tool steel is approximately Hv 240, and the hardness after laser surface heat treatment is around Hv 480-510. The hardening depth and width are increased with the increase in the heat input applied. Application of experimental results will be considered in tooling industry.

  18. On the chemical nature of boundary lubrication of stainless steel by chlorine - and sulfur-containing EP-additives

    DEFF Research Database (Denmark)

    Petrushina, Irina; Christensen, Erik; Bergqvist, Rene Stig

    2000-01-01

    The nature of the extreme pressure CEP) effect of the dialkylpolysulfides and chlorinated paraffins during the ironing of stainless steel AISI 304 has been studied. A strip reduction test was used in combination with differential thermal analysis (DTA), profilometry, X-ray photoelectron...... was equally active with iron, chromium and nickel. The better lubrication performance demonstrated by chlorinated paraffin compared to dialkylpolysulfides was attributed to the chemical activity of the chlorinated paraffin with all the main components of stainless steel. The depth profiles of the stainless...... steel strips were examined before and after strip reduction by use of AES sputter profiling. Results imply that the chlorine containing lubricant enforces the formation of a thick oxide layer. (C) 2000 Elsevier Science S.A. All rights reserved....

  19. Cutting Forces Analysis in Additive Manufactured AISI H13 Alloy

    OpenAIRE

    Montevecchi, Filippo; Grossi, Niccolò; Takagi, Hisataka; Scippa, Antonio; Sasahara, Hiroyuki; Campatelli, Gianni

    2016-01-01

    Combining Additive Manufacturing (AM) and traditional machining processes is essential to meet components functional requirements. However significant differences arise in machining AM and wrought parts. Previous works highlighted the increasing of tool wear and worse surface finish. In this paper cutting forces are investigated as an indicator of material machinability. Milling cutting force coefficients are identified using mechanistic approach, comparing AISI-H13 wrought and AM specimen. C...

  20. Fatigue of annealed and cold worked stable and unstable stainless steels

    Science.gov (United States)

    Schuster, G.; Altstetter, C.

    1983-10-01

    Fatigue crack growth rates (FCGR) in AISI 301 and 302 austenitic stainless steel alloys have been measured in controlled load cycles with R = 0.05. Both annealed and cold rolled conditions were examined. The austenite phase of the AISI 301 alloy was unstable under stress and transformed martensitically to α' to a much greater extent than the AISI 302 alloy. At low values of mean stress the unstable alloy had a lower FCGR than the more stable 302 alloy. The FCGR increased with mean stress until values of mean stress ⪞70 MPa, where the FCGR was independent of mean stress and was the same for both alloys. Various metallographic and macroscopic measurements were made to try to understand this behavior. It was concluded that residual compressive stress due to transformation at the crack tip was responsible for the lower crack growth rates of the unstable 301 alloy. Cold worked specimens had significantly lower crack growth rates than the annealed specimens, and both alloys behaved identically.

  1. 304L无缝钢管二辊斜轧穿孔裂纹的形成原因%Causes of Crack Formation in 304L Seamless Steel Pipe during Double-Roll Cross Piercing Process

    Institute of Scientific and Technical Information of China (English)

    王宝顺; 邵羽; 李三; 赵芳馨; 沈红英; 朱新强

    2013-01-01

    The mechanism of cracking in 304L seamless steel pipe during double-roll cross piercing processing was analyzed by optical microscopy, thermal-calculation ulation software and scanning electron microscopy. The results show that about 3 vol. % S ferrite phase in the billet and the heterogenous deformation of billet during the piercing process were the main causes of cracking. In addition, the difference of deformability between S ferrite phase and y phase caused both the tensile stress and the shear stress at the interface of two phases higher than the fracture strength of billet, which promoted the formation and growth of the cracks.%采用光学显微镜、热力学计算软件、扫描电镜等分析了304L无缝钢管二辊斜轧穿孔工艺中荒管内部产生裂纹的原因.结果表明:穿孔用钢坯中存在3%左右(体积分数)的δ铁素体相,穿孔工艺中不均匀变形是裂纹产生的主要原因;由于δ相和γ相变形能力不一致,在两相界面上产生超过金属断裂强度的拉应力和切应力则促进了裂纹的形成与扩展.

  2. Effects of laser power density on static and dynamic mechanical properties of dissimilar stainless steel welded joints

    Institute of Scientific and Technical Information of China (English)

    Yan-Peng Wei; Mao-Hui Li; Gang Yu; Xian-Qian Wu; Chen-Guang Huang; Zhu-Ping Duan

    2012-01-01

    The mechanical properties of laser welded joints under impact loadings such as explosion and car crash etc.are critical for the engineering designs. The hardness,static and dynamic mechanical properties of AISI304 and AISI316L dissimilar stainless steel welded joints by CO2 laser were experimentally studied. The dynamic strain-stress curves at the strain rate around 103 s-1 were obtained by the split Hopkinson tensile bar (SHTB).The static mechanical properties of the welded joints have little changes with the laser power density and all fracture occurs at 316 L side.However,the strain rate sensitivity has a strong dependence on laser power density.The value of strain rate factor decreases with the increase of laser power density.The welded joint which may be applied for the impact loading can be obtained by reducing the laser power density in the case of welding quality assurance.

  3. Analysis of the influence of electrolyte on surface finish in electropolished stainless steel

    Science.gov (United States)

    Hernando, M.; Núñez, P. J.; García, E.; Trujillo, R.

    2012-04-01

    Electropolishing is a surface finishing process of metals and alloys that enhances brilliant surface finishes with low surface roughness values. The most widely used electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. The objective of this study was to assess the performance of three commonly used industrial electrolytes in terms of the surface finish of electropolished stainless steel AISI 316L. Each electrolyte had varying sulphuric-phosphoric acid combinations with or without chromic acid. The following electropolishing conditions were assessed: current density, bath temperature, electropolishing time, and initial surface texture. The results revealed that adding chromic acid to the electrolyte did not significantly enhance surface finish, and electropolishing ranges were quite similar for all three electrolytes.

  4. Corrosion properties of S-phase layers formed on medical grade austenitic stainless steel.

    Science.gov (United States)

    Buhagiar, Joseph; Dong, Hanshan

    2012-02-01

    The corrosion properties of S-phase surface layers formed in AISI 316LVM (ASTM F138) and High-N (ASTM F1586) medical grade austenitic stainless steels by plasma surface alloying with nitrogen (at 430°C), carbon (at 500°C) and both carbon and nitrogen (at 430°C) has been investigated. The corrosion behaviour of the S-phase layers in Ringer's solutions was evaluated using potentiodynamic and immersion corrosion tests. The corrosion damage was evaluated using microscopy, hardness testing, inductive coupled plasma mass spectroscopy and X-ray diffraction. The experimental results have demonstrated that low-temperature nitriding, carburising and carbonitriding can improve the localised corrosion resistance of both industrial and medical grade austenitic stainless steels as long as the threshold sensitisation temperature is not reached. Carburising at 500°C has proved to be the best hardening treatment with the least effect on the corrosion resistance of the parent alloy.

  5. Effect of Autogenous Arc Welding Processes on Tensile and Impact Properties of Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; K Shanmugam; V Balasubramanian

    2009-01-01

    The effect of autogeneous arc welding processes on tensile and impact properties of ferritic stainless steel conformed to AISI 409M grade is studied.Rolled plates of 4 mm thickness have been used as the base material for preparing single pass butt welded jointa.Tensile and impact properties,microhardness,microstructure,and fracture surface morphology of continuous current gas tungsten arc welding (CCGTAW),pulsed current gas tungsten arc welding (PCGTAW),and plasma arc welding (PAW) joints are evaluated and the results are compared.It is found that the PAW joints of ferritic stainless steel show superior tensile and impact properties when compared with CCGTAW and PCGTAW joints,and this is mainly due to lower heat input,finer fusion zone grain diameter,and higher fusion zone hardness.

  6. Joining of Dissimilar alloy Sheets (Al 6063&AISI 304 during Resistance Spot Welding Process: A Feasibility Study for Automotive industry

    Directory of Open Access Journals (Sweden)

    Reddy Sreenivasulu

    2014-12-01

    Full Text Available Present design trends in automotive manufacture have shifted emphasis to alternative lightweight materials in order to achieve higher fuel efficiency and to bring down vehicle emission. Although some other joining techniques are more and more being used, spot welding still remains the primary joining method in automobile manufacturing so far. Spot welds for automotive applications should have a sufficiently large diameter, so that nugget pullout mode is the dominant failure mode. Interfacial mode is unacceptable due to its low load carrying and energy absorption capability. Strength tests with different static loading were performed in, to reveal the failure mechanisms for the lap-shear geometry and the cross-tension geometry. Based on the literature survey performed, venture into this work was amply motivated by the fact that a little research work has been conducted to joining of dissimilar materials like non ferrous to ferrous. Most of the research works concentrated on joining of different materials like steel to steel or aluminium alloy to aluminium alloy by resistance spot welding. In this work, an experimental study on the resistance spot weldability of aluminium alloy (Al 6063 and austenitic stainless steel (AISI304 sheets, which are lap joined by using a pedestal type resistance spot welding machine. Welding was conducted using a 45-deg truncated cone copper electrode with 10-mm face diameter. The weld nugget diameter, force estimation under lap shear test and T – peel test were investigated using digital type tensometer attached with capacitive displacement transducer (Mikrotech, Bangalore, Model: METM2000ER1. The results shows that joining of Al 6063 and AISI 304 thin sheets by RSW method are feasible for automotive structural joints where the loads are below 1000N act on them, it is observed that by increasing the spots per unit length, then the joint with standing strength to oppose failure is also increased linearly incase of

  7. The significance of passivation treatments on AISI 314 foam pieces to be used as substrates for catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bortolozzi, J.P.; Banus, E.D.; Milt, V.G.; Gutierrez, L.B. [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Ulla, M.A., E-mail: mulla@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2010-11-01

    Several properties of metallic foams such as their low density, high mechanical strength and good coefficients of heat and mass transfer make them attractive for applications in catalysis. Important modifications in the composition and morphology of the metallic foam surfaces can take place when they are submitted to treatments at high temperatures. These surface changes are due to the migration of some elements from the metallic core to the pore surface, thus inducing a passivation via an oxide layer formation. This new layer avoids further metallic segregation and generates a surface roughness, both effects having a significant impact on the catalytic coating quality. This work analyzes the effects of calcination temperature and time on the chemistry and morphology of the metallic surface corresponding to the AISI 314 stainless steel foams of 50 and 60 ppi. The chemical and morphological surface changes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX) analysis and Laser Raman Spectroscopy (LRS). The application of high temperature treatments on AISI 314 foams promotes the formation of a surface layer containing chromium oxide and spinel-type compounds of chromium, iron and manganese. The optimum treatment temperature for this type of structures seems to be 900 deg. C because both the adhesion and thickness of the layer formed are adequate. For the sample with smaller pores (60 ppi) the optimal treatment time is close to 2 h and for that with larger pores (50 ppi) the recommended time is 20 h. Under these conditions, a compromise is found between adhesion, thickness and surface roughness, suitable for the subsequent deposition of catalytic material.

  8. Optimization of CO2 laser cutting parameters on Austenitic type Stainless steel sheet

    Science.gov (United States)

    Parthiban, A.; Sathish, S.; Chandrasekaran, M.; Ravikumar, R.

    2017-03-01

    Thin AISI 316L stainless steel sheet widely used in sheet metal processing industries for specific applications. CO2 laser cutting is one of the most popular sheet metal cutting processes for cutting of sheets in different profile. In present work various cutting parameters such as laser power (2000 watts-4000 watts), cutting speed (3500mm/min – 5500 mm/min) and assist gas pressure (0.7 Mpa-0.9Mpa) for cutting of AISI 316L 2mm thickness stainless sheet. This experimentation was conducted based on Box-Behenken design. The aim of this work is to develop a mathematical model kerf width for straight and curved profile through response surface methodology. The developed mathematical models for straight and curved profile have been compared. The Quadratic models have the best agreement with experimental data, and also the shape of the profile a substantial role in achieving to minimize the kerf width. Finally the numerical optimization technique has been used to find out best optimum laser cutting parameter for both straight and curved profile cut.

  9. Weld solidification cracking in 304 to 204L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Hochanadel, Patrick W [Los Alamos National Laboratory; Lienert, Thomas J [Los Alamos National Laboratory; Martinez, Jesse N [Los Alamos National Laboratory; Johnson, Matthew Q [Los Alamos National Laboratory

    2010-09-15

    A series of annulus welds were made between 304 and 304L stainless steel coaxial tubes using both pulsed laser beam welding (LBW) and pulsed gas tungsten arc welding (GTAW). In this application, a change in process from pulsed LBW to pulsed gas tungsten arc welding was proposed to limit the possibility of weld solidification cracking since weldability diagrams developed for GTAW display a greater range of compositions that are not crack susceptible relative to those developed for pulsed LBW. Contrary to the predictions of the GTAW weldability diagram, cracking was found.This result was rationalized in terms of the more rapid solidification rate of the pulsed gas tungsten arc welds. In addition, for the pulsed LBW conditions, the material compositions were predicted to be, by themselves, 'weldable' according to the pulsed LBW weldability diagram. However, the composition range along the tie line connecting the two compositions passed through the crack susceptible range. Microstructurally, the primary solidification mode (PSM) of the material processed with higher power LBW was determined to be austenite (A), while solidification mode of the materials processed with lower power LBW apparently exhibited a dual PSM of both austenite (A) and ferrite-austenite (FA) within the same weld. The materials processed by pulsed GTAW showed mostly primary austenite solidification, with some regions of either primary austenite-second phase ferrite (AF) solidification or primary ferrite-second phase austenite (FA) solidification. This work demonstrates that variations in crack susceptibility may be realized when welding different heats of 'weldable' materials together, and that slight variations in processing can also contribute to crack susceptibility.

  10. Investigation on the adsorption of alkoxysilanes on stainless steel.

    Science.gov (United States)

    Huser, Julien; Bistac, Sophie; Brogly, Maurice; Delaite, Christelle; Lasuye, Thierry; Stasik, Bernard

    2013-11-01

    Alkoxysilanes, and mainly trialkoxysilanes, have been widely used as coupling agents on metallic surfaces. They are of interest mainly because they form a water-stable covalent bond with a surface composed of hydroxides. The grafting of these molecules should also give rise to the formation of a siloxane network at the substrate's surface. However, only a few studies examine stainless steel substrate, such as AISI 316L, for which the main difficulty is the low surface reactivity. In order to improve the silane anchoring, a prehydrolysis of the alkoxysilane was performed to transform the methoxy groups into silanol groups. This reaction happened in an aqueous medium and at a controlled pH, which impacted the prehydrolysis efficiency. Curing followed this step, which allows the grafting of the alkoxysilane on stainless steel's surface. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) was performed in order to identify the grafting of the silane molecules. Tests were made to compare the grafting of alkoxysilanes as a function of their functional groups and their prehydrolysis conditions. PM-IRRAS coupled with atomic force microscopy allowed the observation of the grafting of the studied alkoxysilanes. The nature of the remaining functional group (its ability to react with polymer, for example) of the alkoxysilane plays a major role in this process, since its chemical nature influences the grafting mechanism.

  11. Estudio de impedancia de la corrosión del acero inoxidable AISI 316L en las regiones pasiva y de picadura

    Directory of Open Access Journals (Sweden)

    Polo Sanz, José Luis

    1999-12-01

    Full Text Available Impedance measurements were performed on an AISI 316L stainless steel immersed in a 5% NaCl solution at room temperature. Some samples were polarized up to the passive and pitting regions, respectively. The Nyquist plots in the rest potential and in the passive region show high impedance with capacitive behaviour. The impedance diagram in the pitting region shows three loops: a capacitive loop at high frequencies, a loop with inductive effects at intermediate frequencies, and a second capacitive response at low frequencies. To validate the impedance data Kramers-Kronig relations were applied in the pitting región.

    Se estudia la corrosión del acero inoxidable AISI 316L en solución de NaCl al 5% y a temperatura ambiente, utilizándose probetas polarizadas hasta las regiones pasiva y de picadura. Se obtuvieron diagramas de impedancia en el potencial de corrosión y en esas dos regiones. Los diagramas de impedancia en el potencial de corrosión y en la región pasiva muestran comportamiento capacitivo. En la región de picadura los diagramas de impedancia presentan tres bucles capacitivos: un bucle capacitivo a altas frecuencias, un bucle con efectos inductivos a frecuencias intermedias y un segundo bucle capacitivo a bajas frecuencias. Se aplicaron las transformadas de Kramers-Kronig a los resultados de impedancia obtenidos en la región de picadura.

  12. 奥氏体不锈钢低温气体渗碳过程中温度对渗碳层的影响%Effect of temperature on low-temperature gas carburized layer of austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      利用扫描电镜、电子探针、显微硬度计、CS电化学工作站研究AISI316奥氏体不锈钢经低温气体渗碳处理后渗碳层显微组织及力学特性的变化。结果表明,在450,470,500℃温度条件下,在AISI316奥氏体不锈钢表面获得10~33μm的硬化层,随温度的不同,渗层深度、硬度梯度、耐蚀性能呈现不同的变化规律。%Microstructure and mechanical properties of low⁃temperature gas carburized layer of AISI316 austenitic stainless steel were investigated by means of scanning electron microscopy(SEM),micro hardness tester,CS electrochemical workstation. The experimental results indicate that the thickness of hardened layer is within the range of 10 to 33 μm,when AISI316 austenitic stainless steel is carburized at 450,470,500 ℃. With the variation of carburizing temperature,different case depth,hardness gradient and corrosion resistance are observed in the steel.

  13. Formability of stainless steel tailored blanks

    DEFF Research Database (Denmark)

    Bagger, Claus; Gong, Hui; Olsen, Flemming Ove

    2004-01-01

    In a number of systematic tests, the formability of tailored blanks consisting of even and different combinations of AISI304 and AISI316 in thickness of 0.8 mm and 1.5 mm have been investigated. In order to analyse the formability of tailored blanks with different sheet thickness, a method based ...

  14. Mössbauer studies on an AISI 1137 type steel

    Indian Academy of Sciences (India)

    E Güler; H Akta

    2006-06-01

    An AISI 1137 type medium carbon steel was studied by means of scanning electron microscopy and Mössbauer spectroscopy. This steel in as received state at room temperature was ferritic. Different heat treatments on related steel exhibited different microstructures such as pearlite and bainite. Also magnetism of these product phases was determined as 32.7 T and 32.6 T relatively where ferromagnetism of ferritic phase in as received state was 33.05 T. Mössbauer parameters such as isomer shifts and % volumes were also determined before and after transformations.

  15. A study of cumulative fatigue damage in AISI 4130 steel

    Science.gov (United States)

    Jeelani, S.; Musial, M.

    1986-01-01

    Experimental data were obtained using AISI 4130 steel under stress ratios of -1 and 0. A study of cumulative fatigue damage using Miner's and Kramer's equations for stress ratios of -1 and 0 for low-high, low-high-mixed, high-low, and high-low-mixed stress sequences has revealed that there is a close agreement between the theoretical and experimental values of fatigue damage and fatigue life. Kramer's equation predicts less conservative and more realistic cumulative fatigue damage than the popularly used Miner's rule does.

  16. Influence of Plastic Deformation on Low Temperature Surface Hardening of Austenitic and Precipitation Hardening Stainless Steels by Gaseous Nitriding

    DEFF Research Database (Denmark)

    Bottoli, Federico; Winther, Grethe; Christiansen, Thomas Lundin;

    2015-01-01

    This article addresses an investigation of the influence of plastic deformation on low temperature surface hardening by gaseous nitriding of three commercial austenitic stainless steels: AISI 304, EN 1.4369 and Sandvik Nanoflex® with various degrees of austenite stability. The materials were...... plastically deformed to different equivalent strains by uniaxial tension. Gaseous nitriding of the strained material was performed in ammonia gas at atmospheric pressure at 703 K (430 °C) and 693 K (420 °C) depending on the material. Microstructural characterization of the as-deformed states and the nitrided...

  17. Influence of Citric Acid on the Metal Release of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Mazinanian, N.; Wallinder, I. Odnevall; Hedberg, Y. S. [KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Stockholm (Sweden)

    2015-08-15

    Knowledge of how metal releases from the stainless steels used in food processing applications and cooking utensils is essential within the framework of human health risk assessment. A new European standard test protocol for testing metal release in food contact materials made from metals and alloys has recently been published by the Council of Europe. The major difference from earlier test protocols is the use of citric acid as the worst-case food simulant. The objectives of this study were to assess the effect of citric acid at acidic, neutral, and alkaline solution pH on the extent of metal release for stainless steel grades AISI 304 and 316, commonly used as food contact materials. Both grades released lower amounts of metals than the specific release limits when they were tested according to test guidelines. The released amounts of metals were assessed by means of graphite furnace atomic absorption spectroscopy, and changes in the outermost surface composition were determined using X-ray photoelectron spectroscopy. The results demonstrate that both the pH and the complexation capacity of the solutions affected the extent of metal release from stainless steel and are discussed from a mechanistic perspective. The outermost surface oxide was significantly enriched in chromium upon exposure to citric acid, indicating rapid passivation by the acid. This study elucidates the effect of several possible mechanisms, including complex ion- and ligand-induced metal release, that govern the process of metal release from stainless steel under passive conditions in solutions that contain citric acid.

  18. Fabrication of antibacterial and hydrophilic electroless Ni-B coating on 316L stainless steel

    Science.gov (United States)

    Bülbül, Ferhat; Bülbül, Leman Elif

    2016-01-01

    Biomaterial-associated bacterial infection is one of the most common complications with medical vehicles and implants made of stainless steel. A surface coating treatment like electroless Ni-B deposition, a new candidate to be used in a broad range of engineering applications owing to many advantages such as low cost, thickness uniformity, good wear resistance, may improve the antibacterial activity and physical properties of biomedical devices made of stainless steel. In this study, the antibacterial property of the electroless Ni-B film coated on AISI 316L (UNS S31603) stainless steel is basically investigated. Inhibition halo diameter measurement after incubation at 37 °C and 24 h demonstrates the existence of antimicrobial activity of the electroless Ni-B coating deposited on 316L stainless steel over the Escherichia coli test bacteria. The results of X-ray diffraction, scanning electron microscopy, atomic force microscopy and microhardness measurement studies confirms that the coating deposited on the substrate has an uniform amorphous and a harder structure. Besides, the wettability property of the uncoated substrate and the coating was measured as the contact angle of water. The water contact angle reduced about from 97.7 to 69.25°.

  19. Investigation on the Tribology of Co Implanted Stainless Steel Using Metal Vapor Vacuum Arc Ion Source

    Institute of Scientific and Technical Information of China (English)

    Junxia GUO; Xun CAI; Qiulong CHEN

    2004-01-01

    AISI 304 stainless steel was ion implanted with Co, and the tribological property on the surface of the stainless steel was investigated. The Co ion implantation was carried out using a metal vapor vacuum arc (Mevva) broad-beam ion source with an extraction voltage of 40 kV, implantation doses of 3×1017/cm2 and 5×1017/cm2, and ion current densities of 13, 22 and 32 μA/cm2. The results showed that the near-surface hardness of Co-implanted stainless steel sample was increased by 50% or more, and it increased with increasing ion current density at first and then declined. The friction coefficient decreased from 0.74 to 0.20 after Co implantation. The wear rate after Co implantation reduced by 25% or more as compared to the unimplanted sample. The wear rate initially decreased with increasing ion current density and then an increase was observed. Within the range of experimental parameters, there exists a critical ion current density for the Co-implanted stainless steel, at which the wear rate decreased with increasing retained dose, going through a minimum and then increased. The critical ion current density in this paper is about 22 μA/cm2.

  20. Dynamical recrystallization of high purity austenitic stainless steels; Recristallisation dynamique d'aciers inoxydables austenitiques de haute purete

    Energy Technology Data Exchange (ETDEWEB)

    Gavard, L

    2001-01-01

    The aim of this work is to optimize the performance of structural materials. The elementary mechanisms (strain hardening and dynamical regeneration, germination and growth of new grains) occurring during the hot working of metals and low pile defect energy alloys have been studied for austenitic stainless steels. In particular, the influence of the main experimental parameters (temperature, deformation velocity, initial grain size, impurities amount, deformation way) on the process of discontinuous dynamical recrystallization has been studied. Alloys with composition equal to those of the industrial stainless steel-304L have been fabricated from ultra-pure iron, chromium and nickel. Tests carried out in hot compression and torsion in order to cover a wide range of deformations, deformation velocities and temperatures for two very different deformation ways have allowed to determine the rheological characteristics (sensitivity to the deformation velocity, apparent activation energy) of materials as well as to characterize their microstructural deformations by optical metallography and electron back-scattered diffraction. The influence of the initial grain size and the influence of the purity of the material on the dynamical recrystallization kinetics have been determined. An analytical model for the determination of the apparent mobility of grain boundaries, a semi-analytical model for the dynamical recrystallization and at last an analytical model for the stationary state of dynamical recrystallization are proposed as well as a new criteria for the transition between the refinement state and the state of grain growth. (O.M.)

  1. Enhancing the corrosion resistance of dentistry drills by plasma immersion nitrogen in implantation of AISI 434-based SS

    Energy Technology Data Exchange (ETDEWEB)

    Munoz C, A.E.; Lopez C, R.; Fuentes G, D.; Valencia A, R. [UAEM, Facultad de Quimica, Instituto Literario 100, Toluca (Mexico)]. e-mail: rlc@nuclear.inin.mx

    2007-07-01

    In order to enhance the resistance to the pitting corrosion due to asepsis processes and to avoid structural fractures in dentistry drills, a plasma immersion ion implantation (PIII) treatment using nitrogen has been performed. The selected drill samples, made of AISI 434 based stainless steel with a 0.670 mm diameter, were treated at a -1kV bias between 350 C and 450 C, this temperature being controlled by both a 20-50 {mu}s pulse width and a 200-1000 Hz repetition rate in the bias. The drills were analysed by cyclic potentiodynamic tests showing a good pitting corrosion resistance when treated at around 400 C, as follows from a resulting very low hysteresis loop. Yet, the resistance appears somehow diminished by the presence of sputtering when processed at temperatures near 450 C. It is also found that the PIII nitriding effectiveness appears to be limited by the appearance of uniform corrosion. Finally, X-ray diffraction of the samples has revealed the presence of two new phases, namely {epsilon}-Fe{sub 2}N and Fe{sub 4.4}N, while scanning electron microscopy of the treated surfaces has suggested a sputtering enhancement at the highest temperatures. (Author)

  2. Separation of surface, subsurface and volume fatigue damage effects in AISI 348 steel for power plant applications

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Martin; Nowak, David; Walther, Frank [Technical Univ. Dortmund (Germany). Dept. of Materials Test Engineering (WPT); Starke, Peter [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Boller, Christian [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Fraunhofer IZFP, Saarbruecken (Germany)

    2016-08-01

    A wide range of industries including energy, chemistry, pharmacy, textiles, food and drink, pulp and paper, etc. is using stainless steels. Metastable austenitic steels such as used in power plants and chemical industry are subjected to cyclic mechanical and thermal loading in air as well as under the influence of corrosive media. This paper provides an overview on different nondestructive and electrochemical measurement techniques, which allow differentiating fatigue damage effects in total strain controlled multiple and constant amplitude tests with respect to damage appearance on surface, in subsurface area as well as in volume of specimens or components microstructure. In addition to conventional mechanical stress-strain hysteresis curves, electrical resistance, magnetic and open circuit potential measurements have been applied to characterize the cyclic deformation behavior of the metastable austenitic steel AISI 348 (X10CrNiNb18-9) in laboratory air and in distilled water. Based on these results obtained, the paper provides an outlook on the possibility for an efficient (remaining) fatigue life evaluation approach, which is adapted to the needs of the application areas.

  3. Modeling of residual stress mitigation in austenitic stainless steel pipe girth weldment

    Energy Technology Data Exchange (ETDEWEB)

    Li, M.; Atteridge, D.G.; Anderson, W.E. [Oregon Graduate Inst., Portland, OR (United States); West, S.L. [Westinghouse Savannah River Co., Aiken, SC (United States)

    1994-03-01

    This study provides numerical procedures to model 40-cm-diameter, schedule 40, Type 304L stainless steel pipe girth welding and a newly proposed post-weld treatment. The treatment can be used to accomplish the goal of imparting compressive residual stresses at the inner surface of a pipe girth weldment to prevent/retard the intergranular stress corrosion cracking (IGSCC) of the piping system in nuclear reactors. This new post-weld treatment for mitigating residual stresses is cooling stress improvement (CSI). The concept of CSI is to establish and maintain a certain temperature gradient across the pipe wall thickness to change the final stress state. Thus, this process involves sub-zero low temperature cooling of the inner pipe surface of a completed girth weldment, while simultaneously keeping the outer pipe surface at a slightly elevated temperature with the help of a certain heating method. Analyses to obtain quantitative results on pipe girth welding and CSI by using a thermo-elastic-plastic finite element model are described in this paper. Results demonstrate the potential effectiveness of CSI for introducing compressive residual stresses to prevent/retard IGSCC. Because of the symmetric nature of CSI, it shows great potential for industrial application.

  4. Microstructure and Interfacial Reactions During Active Metal Brazing of Stainless Steel to Titanium

    Science.gov (United States)

    Laik, A.; Shirzadi, A. A.; Tewari, R.; Kumar, Anish; Jayakumar, T.; Dey, G. K.

    2013-05-01

    Microstructural evolution and interfacial reactions during active metal vacuum brazing of Ti (grade-2) and stainless steel (SS 304L) using a Ag-based alloy containing Cu, Ti, and Al was investigated. A Ni-depleted solid solution layer and a discontinuous layer of (Ni,Fe)2TiAl intermetallic compound formed on the SS surface and adjacent to the SS-braze alloy interface, respectively. Three parallel contiguous layers of intermetallic compounds, CuTi, AgTi, and (Ag,Cu)Ti2, formed at the Ti-braze alloy interface. The diffusion path for the reaction at this interface was established. Transmission electron microscopy revealed formation of nanocrystals of Ag-Cu alloy of size ranging between 20 and 30 nm in the unreacted braze alloy layer. The interdiffusion zone of β-Ti(Ag,Cu) solid solution, formed on the Ti side of the joint, showed eutectoid decomposition to lamellar colonies of α-Ti and internally twinned (Cu,Ag)Ti2 intermetallic phase, with an orientation relationship between the two. Bend tests indicated that the failure in the joints occurred by formation and propagation of the crack mostly along the Ti-braze alloy interface, through the (Ag,Cu)Ti2 phase layer.

  5. Effect of cold work on low-temperature sensitization behaviour of austenitic stainless steels

    Science.gov (United States)

    Kain, V.; Chandra, K.; Adhe, K. N.; De, P. K.

    2004-09-01

    The effects of cold work and low-temperature sensitization heat treatment of non-sensitized austenitic stainless steels have been investigated and related to the cracking in nuclear power reactors. Types 304, 304L and 304LN developed martensite after 15% cold working. Heat treatment of these cold worked steels at 500 °C led to sensitization of grain boundaries and the matrix and a desensitization effect was seen in 11 days due to fast diffusion rate of chromium in martensite. Types 316L and 316LN did not develop martensite upon cold rolling due to its chemical composition suppressing the martensite transformation (due to deformation) temperature, hence these were not sensitized at 500 °C. The sensitization of the martensite phase was always accompanied by a hump in the reactivation current peak in the double loop electrochemical potentiokinetic reactivation test, thus providing a test to detect such sensitization. It was shown that bending does not produce martensite and therefore, is a better method to simulate weld heat affected zone. Bending and heating at 500 °C for 11 days led to fresh precipitation due to increased retained strain and desensitization of 304LN due to faster diffusion rate of chromium along dislocations. The as received or solution annealed 304 and 304LN with 0.15% nitrogen showed increased sensitization after heat treatment at 500 °C, indicating the presence of carbides/nitrides.

  6. Gas-phase hydrogen permeation through alpha iron, 4130 steel, and 304 stainless steel from less than 100 C to near 600 C

    Science.gov (United States)

    Nelson, H. G.; Stein, J. E.

    1973-01-01

    Gas phase hydrogen permeation studies were conducted on hollow, cylindrical membranes of triply zone-refined alpha iron, AISI 304 austenitic stainless steel, and AISI-SAE 4130 steel in both the normalized (ferrite and carbide) and quenched and tempered (martensite) conditions. Membrane temperature was varied from less than 100 C to near 600 C and hydrogen pressure was varied. For one membrane material, normalized 4130 steel, gas phase hydrogen transport under both steady state and nonsteady state conditions was demonstrated to be controlled by lattice diffusion. Additionally, Sievert's law was shown to be applicable. For all membrane materials, expressions for the coefficients for hydrogen permeation were determined by analysis of steady state transport; the coefficients for diffusion were determined by the lag time technique applied to nonsteady state transport; and through a knowledge of the Sievert's constants, the subsurface equilibrium lattice hydrogen concentrations were determined.

  7. A comparative study of graphene-coated stainless steel fiber felt and carbon cloth as anodes in MFCs.

    Science.gov (United States)

    Hou, Junxian; Liu, Zhongliang; Li, Yanxia; Yang, Siqi; Zhou, Yu

    2015-05-01

    This study investigated the stainless steel-based materials and their potential in microbial fuel cells (MFCs) anode application. Herein, AISI 316L stainless steel fiber felts (SSFFs) were used as anodes in MFCs and their performance was compared with the carbon cloth anode MFCs. The experimental results showed that the unmodified carbon cloth (CC) anode had a better performance than the unmodified SSFF anode. However, after coating a thin layer of graphene (GN) on SSFF and CC, the power density of the MFC equipped with the modified SSFF was 2,143 mW m(-2), much higher than that of the graphene-modified CC-MFC which was only 1,018 mW m(-2). The experimental results proved that the use of durable metallic backbones combined with a thin layer of carbon nanoparticles offers exciting opportunities in the advancement of MFC anode design.

  8. Comparison of the tribological properties at 25 C of seven different polyimide films bonded to 301 stainless steel

    Science.gov (United States)

    Fusaro, R. L.

    1980-01-01

    A pin-on-disk type of friction and wear apparatus was used to study the tribological properties of seven different polyimide films bonded to AISI 301 stainless steel disks at 25 C. It was found that the substrate material was extremely influential in determining the lubricating ability of the polyimide films. All seven films spalled in less than 1000 cycles of sliding. This was believed to be caused by poor adherence to the 301 stainless steel or the inability of the films to withstand the high localized tensile stresses imparted by the deformation of the soft substrate under sliding conditions. The friction coefficients obtained for six of the polyimides varied between 0.21 to 0.32 while one varied between 0.32 to 0.39.

  9. Evaluación del grado de sensibilización en el acero inoxidable AISI

    Directory of Open Access Journals (Sweden)

    González, O.

    2003-12-01

    Full Text Available Austenitic stainless steel, when heat-treated at 550-850 °C, became susceptible to intergranular corrosion in acids. This phenomenon, know as sensitization, it is result from the precipitation of chrome carbides in the grain boundary, making these areas less resistant to corrosion. Two different electrochemical reactivation tests are compared with a destructive test and related to the classification of its respective microstructures. It was established a quantitative methodology to evaluate the degree of sensitization in AISI 304 and also to compare the correspondence of the results with the data of the automatic and portable EPR device for non-destructive field measurement of the degree of sensitization. The used electrochemical techniques were the EPR (Electrochemical Potentiokinetic Reactivation or single loop test and the PRP (Pasivation Reactivation Potentiokinetic or double loop test. The destructive test used was boiling, 120 h ferric sulfate-50 % sulfuric acid, according to the standard practices ASTM A-262 practices B. The classifications of each structures were according to the standard practices ASTM A-262 practices B.

    El acero inoxidable austenítico, cuando se calienta en un rango de temperatura entre 550 y 850 °C es susceptible a corrosión intergranular en ácidos. Este fenómeno, conocido como sensibilización, es resultado de la precipitación de carburos de cromo en el límite de grano, haciendo esas áreas menos resistentes a la corrosión. Se comparan dos pruebas diferentes de reactivación electroquímica con una prueba destructiva, relacionándolas con su respectiva microestructura. Se estableció una metodología cuantitativa para evaluar el grado de sensibilización del acero AISI 304 y se comparó con los datos generados de una herramienta no destructiva de campo, automática y portátil, para medir el grado de sensibilización. Las técnicas electroquímicas usadas fueron: la EPR (Reactivación electroqu

  10. Fretting of AISI 9310 and selected fretting resistant surface treatments

    Science.gov (United States)

    Bill, R. C.

    1977-01-01

    Fretting wear experiments were conducted with uncoated AISI 9310 mating surfaces, and with combinations incorporating a selected coating to one of the mating surfaces. Wear measurements and SEM observations indicated that surface fatigue, as made evident by spallation and surface crack formation, is an important mechanism in promoting fretting wear to uncoated 9310. Increasing humidity resulted in accelerated fretting, and a very noticeable difference in nature of the fretting debris. Of the coatings evaluated, aluminum bronze with a polyester additive was most effective at reducing wear and minimizing fretting damage to the mating uncoated surface, by means of a selflubricating film that developed on the fretting surfaces. Chromium plate performed as an effective protective coating, itself resisting fretting and not accelerating damage to the uncoated surface.

  11. Experimental survey on the behaviour of AISI 304 steel sheets subjected to perforation

    OpenAIRE

    2010-01-01

    This paper presents and analyzes the behaviour of AISI 304 steel sheets subjected to perforation under a wide range of impact velocities. The relevance of this steel resides in the potential transformation of austenite into martensite during mechanical loading. This process leads to an increase in strength and ductility of the material. It makes the AISI 304 attractive for many engineering applications, especially for building structural elements responsible for absorbing energy under fast lo...

  12. The Effect of Heat Treatments and Coatings on the Outgassing Rate of Stainless Steel Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Mamum, Md Abdullah A. [Old Dominion Univ., Norfolk, VA (United States); Elmustafa, Abdelmageed A, [Old Dominion Univ., Norfolk, VA (United States); Stutzman, Marcy L. [JLAB, Newport News, VA (United States); Adderley, Philip A. [JLAB, Newport News, VA (United States); Poelker, Matthew [JLAB, Newport News, VA (United States)

    2014-03-01

    The outgassing rates of four nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. One chamber remained uncoated throughout, and the last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 deg C following bakes at temperatures between 90 and 400 deg C. Measurements for bare steel showed a significant reduction in the outgassing rate by more than a factor of 20 after a 400 deg C heat treatment (3.5 x 10{sup 12} TorrL s{sup -1}cm{sup -2} prior to heat treatment, reduced to 1.7 x 10{ sup -13} TorrL s{sup -1}cm{sup -2} following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes. The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel. An evaluation of coating composition suggests the presence of elemental titanium which could provide pumping and lead to an artificially low outgassing rate. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.

  13. Improvement of adhesion and barrier properties of biomedical stainless steel by deposition of YSZ coatings using RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Hernández, Z.E. [Instituto Politécnico Nacional, CICATA-Altamira, Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); CICATA—Altamira, IPN. Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); Domínguez-Crespo, M.A., E-mail: mdominguezc@ipn.mx [Instituto Politécnico Nacional, CICATA-Altamira, Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); Torres-Huerta, A.M.; Onofre-Bustamante, E. [Instituto Politécnico Nacional, CICATA-Altamira, Grupo CIAMS, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C. P. 89600, Altamira, Tamps, México (Mexico); Andraca Adame, J. [Instituto Politécnico Nacional, Centro de Nanociencias Micro y Nanotecnologías, Departamento de DRX, C. P. 07300, Mexico, DF, México (Mexico); Dorantes-Rosales, H. [Instituto Politécnico Nacional, ESIQIE, Departamento de Metalurgia, C. P. 07300 Mexico, DF, México (Mexico)

    2014-05-01

    The AISI 316L stainless steel (SS) has been widely used in both artificial knee and hip joints in biomedical applications. In the present study, yttria stabilized zirconia (YSZ, ZrO{sub 2} + 8% Y{sub 2}O{sub 3}) films were deposited on AISI 316L SS by radio-frequency magnetron sputtering using different power densities (50–250 W) and deposition times (30–120 min) from a YSZ target. The crystallographic orientation and surface morphology were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effects of the surface modification on the corrosion performance of AISI 316L SS were evaluated in phosphate buffered saline (PBS) solution using an electrochemical test on both the virgin and coated samples. The YSZ coatings have a (111) preferred orientation during crystal growth along the c-axis for short deposition times (30–60 min), whereas a polycrystalline structure forms during deposition times from 90 to 120 min. The corrosion protective character of the YSZ coatings depends on the crystal size and film thickness. A significant increase in adhesion and corrosion resistance by at least a factor of 46 and a higher breakdown potential were obtained for the deposited coatings at 200 W (120 min). - Highlights: • Well-formed and protective YSZ coatings were achieved on AISI 316L SS substrates. • Films grown at high power and long deposition time have polycrystalline structures. • The crystal size varies from ∼ 5 to 30 nm as both power and deposition time increased. • The differences of corrosion resistance are attributed to internal film structure.

  14. Effects of heat treatment and testing temperature on fracture mechanics behavior of low-Si CA-15 stainless steel

    Science.gov (United States)

    Hsu, Cheng-Hsun; Lee, Shen-Chih; Teng, Hwei-Yuan

    2004-02-01

    This research studied the effects of heat treatment and testing temperature on fracture mechanics behavior of Si-modified CA-15 martensitic stainless steel (MSS), which is similar to AISI 403 grade stainless steel, which has been widely used in wall and blanket structures and in the pipe of nuclear power plant reactors, turbine blades, and nozzles. The results indicated that fracture toughness of low-Si CA-15 MSS is better than that of AISI 403. The specimens of the low-Si CA-15 MSS after austenitization at 1010 °C and then tempering at 300 °C have higher plane-strain fracture toughness (K IC ) values for both 25 °C and -150 °C testing temperatures. However, the specimens tested at 150 °C cannot satisfy the plane-strain fracture toughness criteria. The fatigue crack growth rate is the slowest after austenitization at 1010 °C for 2 hours and tempering at 400 °C. Observing the crack propagation paths using a metallographic test, it was found that the cracking paths preferred orientation and branched along ferrite phase, owing to martensite-phase strengthening and grain-boundary-carbide retarding after 300 °C to 400 °C tempering. Also, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction analysis were performed to correlate the properties attained to the microstructural observation.

  15. Study of residual stresses generated in machining of AISI 4340 steel; Estudo das tensoes residuais geradas na usinagem de aco AISI 4340

    Energy Technology Data Exchange (ETDEWEB)

    Reis, W.P. dos; Fonseca, M.P. Cindra; Serrao, L.F.; Chuvas, T.C.; Oliveira, L.C., E-mail: mcindra@vm.uff.b [Universidade Federal Fluminense (PGMEC/UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Among the mechanical construction steels, AISI 4340 has good harden ability, while combining high strength with toughness and good fatigue strength, making it excellent for application in the metalworking industry, where it can work at different levels and types of requests. Residual stresses are generated in almost all processes of mechanical manufacturing. In this study, the residual stresses generated in different machining processes and heat treatment hardening of AISI 4340 were analyzed by X-ray diffraction, by the sen{sup 2} {psi} method, using Cr{kappa}{beta} radiation and compared. All samples, except for turned and cut by EDM, presented compressive residual stresses in the surface with various magnitudes. (author)

  16. Surface analysis of localized corrosion of austenitic 316L and duplex 2205 stainless steels in simulated body solutions

    Energy Technology Data Exchange (ETDEWEB)

    Conradi, Marjetka, E-mail: marjetka.conradi@imt.si [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia); Schoen, Peter M. [Materials Science and Technology of Polymers and MESA Institute for Nanotechnology, University of Twente, Enschede 7500 AE (Netherlands); Kocijan, Aleksandra; Jenko, M. [Institute of Metals and Technology, Lepi pot 11, 1000 Ljubljana (Slovenia); Vancso, G. Julius [Materials Science and Technology of Polymers and MESA Institute for Nanotechnology, University of Twente, Enschede 7500 AE (Netherlands)

    2011-10-17

    Highlights: {yields} In situ steel surface morphology observations in simulated body solutions. {yields} Pitting, square-like and elliptic-like corrosion products. {yields} Corrosion products' shapes related to the growth of Cr and Fe oxides. {yields} Direct relation of the size of the deposition products to surface roughness. - Abstract: We report on cyclic voltammetry and in situ electrochemical atomic force microscopy (EC-AFM) studies of localized corrosion of duplex 2205 stainless steel (DSS 2205) and austenitic stainless steel of the type AISI 316L in two model solutions, including artificial saliva (AS) and a simulated physiological solution known as - Hank's solution (PS). The AFM topography analysis illustrated the higher corrosion resistance of DSS 2205 steel for the chosen range of electrochemical potentials that were applied to the steel surface in both solutions. In contrast, pitting corrosion was observed at the surface of AISI 316L steel, with the pits becoming more evident, larger and deeper, when the sample was electrochemically treated in the PS. On both surfaces the growth of corrosion products formed during the oxidation process was observed. As a result, depending on the sample's metallurgical structure, different types of oxides covered the surface close to the breakdown potential. We distinguished between the square-like type of oxides on the surface of the DSS 2205, and the AISI 316L with its ellipse-like oxide deposits. The X-ray photoelectron spectroscopy (XPS) revealed the chemical composition of the deposition products, which consisted of two main elements, Fe and Cr. However, the oxides of the alloying elements Ni and Mo were negligible compared to the bulk.

  17. Evaluation of the AISI 904L Alloy Weld Overlays Obtained by GMAW and Electro-Slag Welding Processes

    Science.gov (United States)

    Jorge, Jorge C. F.; Meira, O. G.; Madalena, F. C. A.; de Souza, L. F. G.; Araujo, L. S.; Mendes, M. C.

    2017-03-01

    The use of superaustenitic stainless steels (SASS) as an overlay replacement for nickel-based alloys can be an interesting alternative for the oil and gas industries, due to its lower cost, when compared to superalloys. Usually, the deposition is made with several welding passes by using conventional arc welding processes, such as gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW) processes. In this respect, electro-slag welding (ESW), which promotes high heat inputs and low dilution of the welds, can also be attractive for this application, as it provides a higher productivity, once only one layer is needed for the deposition of the minimum thickness required. The present work evaluates the behavior of an AISI 904L SASS weld overlay deposited on a carbon steel ASTM A516 Grade 70 by ESW and GMAW processes. Both as-welded and heat-treated conditions were evaluated and compared. A multipass welding by GMAW process with three layers and 48 passes was performed on 12.5 × 200 × 250 mm steel plates with average welding energy of 1.0 kJ/mm. For ESW process, only one layer was deposited on 50 × 400 × 400 mm steel plates with average welding energy of 11.7 kJ/mm. After welding, a post-weld heat treatment (PWHT) at 620 °C for 10 h was performed in half of the steel plate, in order to allow the comparison between this condition and the as-welded one. For both processes, the austenitic microstructure of the weld deposits was characterized by optical microscopy and scanning electron microscopy with electron backscatter diffraction. A low proportion of secondary phases were observed in all conditions, and the PWHT did not promote significant changes on the hardness profile. Martensite for GMAW process and bainite for ESW process were the microstructural constituents observed at the coarse grain heat-affected zone, due to the different cooling rates. For ESW process, no evidences of partially diluted zones were found. As a consequence of the microstructural

  18. Cracking kinetics of two-phase stainless steel alloys in hydrogen gas

    Science.gov (United States)

    Perng, T.-P.; Altstetter, C. J.

    1988-01-01

    The kinetics of hydrogen-induced slow crack growth (SCG) under constant load was studied in two stainless steel alloys containing mixtures of bcc and fcc phases. FERRALIUM 255, a duplex stainless steel, consisting of ˜50 pct austenite in a ferrite matrix, was tested in hydrogen gas at 0 to 100 °C with the loading axis both perpendicular and parallel to the rolling direction. In addition, specimens of AISI 301 were deformed in air in different ways to produce various amounts of bcc phase in an austenite matrix prior to testing in H2 gas at room temperature. The kinetics of subcritical slow crack growth (SCG) in these alloys was compared with that for austenitic and for ferritic stainless steels. The SCG rates were rationalized in terms of differences in hydrogen permeation in the two phases. The results confirm that a higher rate of supply and accumulation of hydrogen in the region ahead of the crack tip allows a higher cracking velocity.

  19. Intergran