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Sample records for arc stainless steel

  1. Grain size distribution after similar and dissimilar gas tungsten arc welding of a ferritic stainless steel

    OpenAIRE

    Ranjbarnodeh E.; Serajzadeh S.; Kokabi A.H.; Fischer A

    2015-01-01

    In this study, gas tungsten arc welding of ferritic stainless steel and grain size distribution in heat affected zone of the welded samples were investigated. Both similar and dissimilar arc welding operations were considered where in dissimilar welding joining of stainless steel to mild steel was examined. In the first stage, a three-dimensional model was developed to evaluate temperature field during and after arc welding while the model was performed usi...

  2. Fatigue Crack Growth Behavior of Gas Metal Arc Welded AISI 409 Grade Ferritic Stainless Steel Joints

    Science.gov (United States)

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

    2009-10-01

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel, and duplex stainless steel on fatigue crack growth behavior of the gas metal arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single ‘V’ butt welded joints. Center cracked tensile specimens were prepared to evaluate fatigue crack growth behavior. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN was used to evaluate the fatigue crack growth behavior of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue crack growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  3. Grain size distribution after similar and dissimilar gas tungsten arc welding of a ferritic stainless steel

    Directory of Open Access Journals (Sweden)

    Ranjbarnodeh E.

    2015-01-01

    Full Text Available In this study, gas tungsten arc welding of ferritic stainless steel and grain size distribution in heat affected zone of the welded samples were investigated. Both similar and dissimilar arc welding operations were considered where in dissimilar welding joining of stainless steel to mild steel was examined. In the first stage, a three-dimensional model was developed to evaluate temperature field during and after arc welding while the model was performed using finite element software, ANSYS. Then, the effects of welding heat input and dissimilarity of the joint on the weld pool shape and grain growth in HAZ of stainless steel was investigated by means of model predictions and experimental observations. The results show that the similar joint produces wider HAZ and considerably larger grain size structure while in the dissimilar welds, the low carbon part acts as an effective heat sink and prevents the grain growth in the stainless steel side as well reduces the welding maximum temperature.

  4. Analysis of arc emission spectra of stainless steel electric arc furnace slag affected by fluctuating arc voltage.

    Science.gov (United States)

    Aula, Matti; Mäkinen, Ari; Fabritius, Timo

    2014-01-01

    Control of chromium oxidation in the electric arc furnace (EAF) is a significant problem in stainless steel production due to variations of the chemical compositions in the EAF charge. One potential method to control chromium oxidation is to analyze the emission spectrum of the electric arc in order to find indicators of rising chromium content in slag. The purpose of this study was to determine if slag composition can be gained by utilizing electric arc emission spectra in the laboratory environment, despite electric arc voltage fluctuations and varying slag composition. The purpose of inducing voltage fluctuation was to simulate changes in the industrial EAF process. The slag samples were obtained from Outokumpu Stainless Oy Tornio Works, and three different arc currents were used. The correlation analysis showed that the emission spectra offer numerous peak ratios with high correlations to the X-ray fluorescence-measured slag CrO(x)/FeO(x) and MnO/SiO2 ratios. These ratios are useful in determining if the reduction agents have been depleted in the EAF. The results suggest that analysis of laboratory-scale electric arc emission spectra is suitable for indicating the high CrO(x) or MnO content of the slag despite the arc fluctuations. Reliable analysis of other slag components was not successful.

  5. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    OpenAIRE

    Koray Yurtisik; Suha Tirkes; Igor Dykhno; C. Hakan Gur; Riza Gurbuz

    2013-01-01

    Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

  6. Evaluation of Dry Sliding Wear Behaviour of Plasma Transferred Arc Hardfaced Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    C S Ramachandran; V Balasubramanian; R Varahamoorthy

    2009-01-01

    The effects of different experimental conditions on the dry sliding wear behavior of stainless steel surface produced by plasma transferred arc (PTA) hardfacing process were studied. The wear test was conducted in a pinon-roller wear testing machine, at constant sliding distance of 1 km. Mathematical models were developed to estimate wear rate incorporating with rotational speed, applied load and roller hardness using statistical tools such as design of experiments, regression analysis and analysis of variance. It is found that the wear resistance of the PTA hardfaced stainless steel surface is better than that of the carbon steel substrate.

  7. 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.

  8. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    Directory of Open Access Journals (Sweden)

    Koray Yurtisik

    2013-09-01

    Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

  9. Microstructure and Mechanical Properties of Plasma Arc Brazed AISI 304L Stainless Steel and Galvanized Steel Plates

    Science.gov (United States)

    Jin, Yajuan; Li, Ruifeng; Yu, Zhishui; Wang, Yu

    2016-04-01

    Plasma arc brazing is used to join the AISI 304L stainless steel and galvanized steel plate butt joints with the CuSi3Mn1 filler wire. The effect of parameters on weld surface appearance, interfacial microstructure, and composition distribution in the joint was studied. The microhardness and mechanical tests were conducted to determine the mechanical properties of the welded specimens. The results indicated that good appearance, bead shape, and sufficient metallurgical bonding could be obtained when the brazing process was performed with a wire feeding speed of 0.8 m/min, plasma gas flow rate of 3.0 l/min, welding current of 100 A, and welding speed of 27 cm/min. During plasma arc brazing process, the top corner of the stainless steel and galvanized steel plate were heated and melted, and the melted quantity of stainless steel was much more than that of the galvanized steel due to the thermal conductivity coefficient difference between the dissimilar materials. The microhardness test results shows that the microhardness value gradually increased from the side of the galvanized steel to the stainless steel in the joint, and it is good for improving the mechanical properties of joint. The tensile strength was a little higher than that of the brazing filler, and the fracture position of weld joint was at the base metal of galvanized steel plate.

  10. Stainless steel submerged arc weld fusion line toughness

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfield, A.R.; Held, P.R.; Wilkowski, G.M. [Battelle, Columbus, OH (United States)

    1995-04-01

    This effort evaluated the fracture toughness of austenitic steel submerged-arc weld (SAW) fusion lines. The incentive was to explain why cracks grow into the fusion line in many pipe tests conducted with cracks initially centered in SAWS. The concern was that the fusion line may have a lower toughness than the SAW. It was found that the fusion line, Ji. was greater than the SAW toughness but much less than the base metal. Of greater importance may be that the crack growth resistance (JD-R) of the fusion line appeared to reach a steady-state value, while the SAW had a continually increasing JD-R curve. This explains why the cracks eventually turn to the fusion line in the pipe experiments. A method of incorporating these results would be to use the weld metal J-R curve up to the fusion-line steady-state J value. These results may be more important to LBB analyses than the ASME flaw evaluation procedures, since there is more crack growth with through-wall cracks in LBB analyses than for surface cracks in pipe flaw evaluations.

  11. 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.)

  12. 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.

  13. Thermocapillary and arc phenomena in stainless steel welds

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, S.W.

    1993-10-01

    Goal was to study effect of power level and distribution on thermocapiilary-induced weld shape and of arc factors on weld shape. Thermocapillarity was apparent in both conduction mode EB welds and GTA welds, particularly in the former. A non-Gaussian arc distribution is suggested for accounting for the differences between the twoss processes. At higher current levels (200--300 A), plasma shear force also contributes to weld shape development. Evidence suggests that thermocapillary flow reversal is not a factor in normal GTA welds; EDB flow reversal occurs only at high power density levels where the keyhole mode is present.

  14. Microstructure and corrosion behavior of multipass gas tungsten arc welded 304L stainless steel

    International Nuclear Information System (INIS)

    Highlights: • Multipass gas tungsten arc welding of 304L stainless steel was successfully done. • All welds were austenitic with the presence of a small amount of δ-ferrite. • The morphology of δ-ferrite showed the lathy and skeletal δ-ferrite in the welds. • Hardness and corrosion resistance were improved by multipass welding. • The best joint properties were obtained after three passes welding. - Abstract: The purpose of this study was to discuss the effect of single pass and multipass (double and triple pass) gas tungsten arc welding (GTAW) on microstructure, hardness and corrosion behavior of 304L stainless steel. In this investigation, 308 stainless steel filler metal was used. Microstructures and hardness of the weldments were investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD) and Vickers microhardness (HV0.5). A ferritescope was also used in the non-destructive evaluation to observe the ferrite content on the weldments. Corrosion behavior of weldments in 1 M H2SO4 solution at 25 ± 1 °C was investigated using potentiodynamic polarization and immersion tests. Results indicated that the microstructure of fusion zones exhibited dendritic structure contained lathy and skeletal δ-ferrite. The contents of δ-ferrite in the weld zone increased by increasing the number of passes. Therefore, as the number of passes increased, the hardness and corrosion resistance increased

  15. Hybrid (plasma + gas tungsten arc) weldability of modified 12% Cr ferritic stainless steel

    International Nuclear Information System (INIS)

    This paper deals with the hybrid (plasma + gas tungsten arc) welding properties of 12 mm thick modified 12% Cr ferritic stainless steel complying with EN 1.4003 and UNS S41003 steels with a carbon content of 0.01% to improve the weldability. The root passes of the butt welds were produced with plasma arc welding (PAW) without filler metal while gas tungsten arc welding (GTAW) was used to accomplish filler passes with 309 and 316 austenitic stainless steel type of consumables, respectively. The joints were subjected to tensile and bend tests as well as Charpy impact toughness testing at -20 oC, 0 oC and 20 oC. Examinations were carried out in terms of metallography, chemical analysis of the weld metal, ferrite content, grain size and hardness analyses. Although 309 consumables provided higher mean weld metal toughness values compared to 316 (90 J vs. 75 J), 316 type of consumables provided better mean HAZ toughness data for the joints (45 J vs. 20 J) at -20 oC. Toughness properties of the welds correspond with those of microstructural features including grain size and ferrite content.

  16. Microstructure and corrosion behavior of shielded metal arc-welded dissimilar joints comprising duplex stainless steel and low alloy steel

    Science.gov (United States)

    Srinivasan, P. Bala; Muthupandi, V.; Sivan, V.; Srinivasan, P. Bala; Dietzel, W.

    2006-12-01

    This work describes the results of an investigation on a dissimilar weld joint comprising a boiler-grade low alloy steel and duplex stainless steel (DSS). Welds produced by shielded metal arc-welding with two different electrodes (an austenitic and a duplex grade) were examined for their microstructural features and properties. The welds were found to have overmatching mechanical properties. Although the general corrosion resistance of the weld metals was good, their pitting resistance was found to be inferior when compared with the DSS base material.

  17. Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints

    Directory of Open Access Journals (Sweden)

    M. Vinoth Kumar

    2015-09-01

    Full Text Available Super 304H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of the material. Stress corrosion cracking susceptibility of Super 304H parent metal and gas tungsten arc (GTA welded joints were studied by constant load tests in 45% boiling MgCl2 solution. Stress corrosion cracking resistance of Super 304H stainless steel was deteriorated by GTA welding due to the formation of susceptible microstructure in the HAZ of the weld joint and the residual stresses. The mechanism of cracking was found to be anodic path cracking, with transgranular nature of crack propagation. Linear relationships were derived to predict the time to failure by extrapolating the rate of steady state elongation.

  18. The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

    Science.gov (United States)

    Neissi, R.; Shamanian, M.; Hajihashemi, M.

    2016-05-01

    In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

  19. Double-Sided Single-Pass Submerged Arc Welding for 2205 Duplex Stainless Steel

    Science.gov (United States)

    Luo, Jian; Yuan, Yi; Wang, Xiaoming; Yao, Zongxiang

    2013-09-01

    The duplex stainless steel (DSS), which combines the characteristics of ferritic steel and austenitic steel, is used widely. The submerged arc welding (SAW) method is usually applied to join thick plates of DSS. However, an effective welding procedure is needed in order to obtain ideal DSS welds with an appropriate proportion of ferrite (δ) and austenite (γ) in the weld zone, particularly in the melted zone and heat-affected zone. This study evaluated the effectiveness of a high efficiency double-sided single-pass (DSSP) SAW joining method for thick DSS plates. The effectiveness of the converse welding procedure, characterizations of weld zone, and mechanical properties of welded joint are analyzed. The results show an increasing appearance and continuous distribution feature of the σ phase in the fusion zone of the leading welded seam. The converse welding procedure promotes the σ phase to precipitate in the fusion zone of leading welded side. The microhardness appears to significantly increase in the center of leading welded side. Ductile fracture mode is observed in the weld zone. A mixture fracture feature appears with a shear lip and tears in the fusion zone near the fusion line. The ductility, plasticity, and microhardness of the joints have a significant relationship with σ phase and heat treatment effect influenced by the converse welding step. An available heat input controlling technology of the DSSP formation method is discussed for SAW of thick DSS plates.

  20. Characterization and leachability of electric arc furnace dust made from remelting of stainless steel.

    Science.gov (United States)

    Laforest, Guylaine; Duchesne, Josée

    2006-07-31

    Electric arc furnace dust (EAFD) is a toxic waste product made in the remelting of scrap steel. The results of a Toxicity Characteristic Leaching Procedure (TCLP) conducted on a sample of EAFD originating from the remelting of stainless steel scrap showed that the total Cr and Cr (VI) liquor concentrations (9.7 and 6.1 mg/L, respectively) exceeded the Toxicity Characteristic Regulatory Level (TCRL). The EAFD showed a complex heterogeneous mineralogy with spinel minerals group predominance. A sequential extractions method has permitted the determination of the amount of available metals (potentially mobile component) from the EAFD as follows: Cr (3%), Ni (6%), Pb (49%) and Zn (40%). Solubility controls on Cr, Pb, Zn and Ni were identified in the EAFD. This means that the Cr, Pb, Zn and Ni concentrations in solution were controlled by the solubility of some phases from EAFD. The concentrations of Ni and Zn, which are metals not regulated by TCRL were below 0.41 and 1.3 mg/L, respectively. The solubility control on Pb was sufficient to decrease its concentration (<0.24 mg/L) to a level below the TCRL. However, the control on Cr was not sufficient to decrease its concentration (between 117 and 331 mg/L) to below the TCRL.

  1. Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints

    OpenAIRE

    M. Vinoth Kumar; Balasubramanian, V.; S. RAJAKUMAR; Shaju K. Albert

    2015-01-01

    Super 304H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of t...

  2. On the fatigue behaviour of electron beam and gas tungsten arc weldments of 409M grade ferritic stainless steel

    International Nuclear Information System (INIS)

    Highlights: ► Fatigue behaviour of EBW and GTAW joints of ferritic stainless steel is reported. ► Effect of the microstructure, tensile properties and residual stresses are discussed. ► EBW joint showed superior fatigue performance compared to GTAW joint. ► Fine dual phase microstructure acted beneficially in retarding the crack growth. -- Abstract: Fatigue life and fatigue crack growth behaviour of the electron beam welded AISI 409M ferritic stainless steel joints in comparison with the gas tungsten arc welded joint and the base metal was studied. It is found that the joint fabricated by the electron beam welding process exhibited superior fatigue performance than that of the gas tungsten arc welded joint. Formation of a dual phase lath ferrite with fine martensitic microstructure, superior tensile properties and favourable residual stress field are the main reasons for the enhanced fatigue life and fatigue crack resistance of the electron beam welded joint.

  3. Laser-Arc Hybrid Welding of Dissimilar Titanium Alloy and Stainless Steel Using Copper Wire

    Science.gov (United States)

    Gao, Ming; Chen, Cong; Wang, Lei; Wang, Zemin; Zeng, Xiaoyan

    2015-05-01

    Laser-arc hybrid welding with Cu3Si filler wire was employed to join dissimilar Ti6Al4V titanium alloy and AISI316 stainless steel (316SS). The effects of welding parameters on bead shape, microstructure, mechanical properties, and fracture behavior were investigated in detail. The results show that cross-weld tensile strength of the joints is up to 212 MPa. In the joint, obvious nonuniformity of the microstructure is found in the fusion zone (FZ) and at the interfaces from the top to the bottom, which could be improved by increasing heat input. For the homogeneous joint, the FZ is characterized by Fe67- x Si x Ti33 dendrites spreading on α-Cu matrix, and the two interfaces of 316SS/FZ and FZ/Ti6Al4V are characterized by a bamboo-like 316SS layer and a CuTi2 layer, respectively. All the tensile samples fractured in the hardest CuTi2 layer at Ti6Al4V side of the joints. The fracture surface is characterized by river pattern revealing brittle cleavage fracture. The bead formation mechanisms were discussed according to the melt flow and the thermodynamic calculation.

  4. Relation between various chromium compounds and some other elements in fumes from manual metal arc stainless steel welding.

    OpenAIRE

    Matczak, W; Chmielnicka, J

    1993-01-01

    For the years 1987-1990 160 individual samples of manual metal arc stainless steel (MMA/SS) welding fumes from the breathing zone of welders in four industrial plants were collected. Concentrations of soluble and insoluble chromium (Cr) III and Cr VI compounds as well as of some other welding fume elements (Fe, Mn, Ni, F) were determined. Concentration of welding fumes in the breathing zone ranged from 0.2 to 23.4 mg/m3. Total Cr amounted to 0.005-0.991 mg/m3 (including 0.005-0.842 mg/m3 Cr V...

  5. Structure and sliding wear behavior of 321 stainless steel/Al composite coating deposited by high velocity arc spraying technique

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-xiong; XU Bin-shi; LIU Yan; LIANG Xiu-bing; XU Yi

    2008-01-01

    A typical 321 stainless steel/aluminum composite coating (321/Al coating) was prepared by high velocity arc spraying technique (HVAS) with 321 stainless steel wire as the anode and aluminum wire as the cathode.The traditional 321 stainless steel coating was also prepared for comparison.Tribological properties of the coatings were evaluated with the ring-block wear tester under different conditions.The structure and worn surface of the coatings were analyzed by scanning electron microscopy (SEM),X-ray diffractometry (XRD) and energy dispersion spectroscopy (EDS).The results show that,except for aluminum phase addition in tne 321/Al coating,no other phases are created compared with the 321 coating.However,due to the addition of aluminum,the 321/Al coating forms a type of "ductile/hard phases inter-deposited" structure and performs quite different tribological behavior.Under the dry sliding condition,the anti-wear property of 321/Al coating is about 42% lower than that of 321 coating.Butunder the oil lubricated conditions with or without 32h oil-dipping pretreatment,the anti-wear property of 321/Al coating is about 9% and 5% higher than that of 321 coating,respectively.The anti-wear mechanism of the composite coating is mainly relevant to the decrease of oxide impurities and the strengthening action resulted from the "ductile/hard phases inter-deposited" coating structure.

  6. Gas tungsten arc and laser beam welding processes effects on duplex stainless steel 2205 properties

    Energy Technology Data Exchange (ETDEWEB)

    Mourad, A-H.I., E-mail: ahmourad@uaeu.ac.ae [Mechanical Engineering Department, Faculty of Engineering, United Arab Emirates University, Al-Ain, P.O. Box. 17555 (United Arab Emirates); Khourshid, A.; Sharef, T. [Mechanical Design and Production Department, Faculty of Engineering, Tanta University, Tanta (Egypt)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer LBW results in considerable variation in the ferrite-austenite balance of FZ. Black-Right-Pointing-Pointer LBW produces smaller FZ size than GTAW. Black-Right-Pointing-Pointer The effect of FZ size is more pronounced than that of ferrite-austenite balance. Black-Right-Pointing-Pointer Satisfactory mechanical properties were obtained using both GTAW and LBW. Black-Right-Pointing-Pointer LBW process has produced welded joint properties comparable to BM. - Abstract: A comparative study on the influence of gas tungsten arc welding (GTAW) and carbon dioxide laser beam welding (LBW) processes on the size and microstructure of fusion zone FZ then, on the mechanical and corrosion properties of duplex stainless steel DSS grade 2205 plates of 6.4 mm thickness was investigated. Autogenous butt welded joints were made using both GTAW and LBW. The GTA welded joint was made using well established welding parameters (i.e., current ampere of 110 A, voltage of 12 V, welding speed of 0.15 m/min and argon shielding rate of 15 l/min). While optimum LBW parameters were used (i.e., welding speed of 0.5 m/min, defocusing distance of 0.0 mm, argon shielding flow rate of 20 l/min and maximum output laser power of 8 kW). The results achieved in this investigation disclose that welding process play an important role in obtaining satisfactory weld properties. In comparison with GTAW, LBW has produced welded joint with a significant decrease in FZ size and acceptable weld profile. The ferrite-austenite balance of both weld metal WM and heat affected zone (HAZ) are influenced by heat input which is a function of welding process. In comparison with LBW, GTAW has resulted in ferrite-austenite balance close to that of base metal BM due to higher heat input in GTAW. However, properties of LB welded joint, particularly corrosion resistance are much better than that of GTA welded joint. The measured corrosion rates for LBW and GTAW joints are 0.05334 mm

  7. Gas tungsten arc and laser beam welding processes effects on duplex stainless steel 2205 properties

    International Nuclear Information System (INIS)

    Highlights: ► LBW results in considerable variation in the ferrite–austenite balance of FZ. ► LBW produces smaller FZ size than GTAW. ► The effect of FZ size is more pronounced than that of ferrite–austenite balance. ► Satisfactory mechanical properties were obtained using both GTAW and LBW. ► LBW process has produced welded joint properties comparable to BM. - Abstract: A comparative study on the influence of gas tungsten arc welding (GTAW) and carbon dioxide laser beam welding (LBW) processes on the size and microstructure of fusion zone FZ then, on the mechanical and corrosion properties of duplex stainless steel DSS grade 2205 plates of 6.4 mm thickness was investigated. Autogenous butt welded joints were made using both GTAW and LBW. The GTA welded joint was made using well established welding parameters (i.e., current ampere of 110 A, voltage of 12 V, welding speed of 0.15 m/min and argon shielding rate of 15 l/min). While optimum LBW parameters were used (i.e., welding speed of 0.5 m/min, defocusing distance of 0.0 mm, argon shielding flow rate of 20 l/min and maximum output laser power of 8 kW). The results achieved in this investigation disclose that welding process play an important role in obtaining satisfactory weld properties. In comparison with GTAW, LBW has produced welded joint with a significant decrease in FZ size and acceptable weld profile. The ferrite–austenite balance of both weld metal WM and heat affected zone (HAZ) are influenced by heat input which is a function of welding process. In comparison with LBW, GTAW has resulted in ferrite–austenite balance close to that of base metal BM due to higher heat input in GTAW. However, properties of LB welded joint, particularly corrosion resistance are much better than that of GTA welded joint. The measured corrosion rates for LBW and GTAW joints are 0.05334 mm/year and 0.2456 mm/year, respectively. This is related to the relatively small size of both WM and HAZ produced in the case

  8. Weldability of Stainless Steels

    International Nuclear Information System (INIS)

    It gives an outline of metallographic properties of welding zone of stainless steels, generation and mechanisms of welding crack and decreasing of corrosion resistance of welding zone. It consists of seven chapters such as introduction, some kinds of stainless steels and properties, metallographic properties of welding zone, weld crack, toughness of welding zone, corrosion resistance and summary. The solidification modes of stainless steels, each solidification mode on the cross section of Fe-Cr-Ni alloy phase diagram, each solidification mode of weld stainless steels metal by electron beam welding, segregation state of alloy elements at each solidification mode, Schaeffler diagram, Delong diagram, effects of (P + S) mass content in % and Cr/Ni equivalent on solidification cracking of weld stainless steels metal, solidification crack susceptibility of weld high purity stainless steels metal, effects of trace impurity elements on solidification crack susceptibility of weld high purity stainless steels metal, ductile fracture susceptibility of weld austenitic stainless steels metal, effects of H2 and ferrite content on generation of crack of weld 25Cr-5N duplex stainless steels, effects of O and N content on toughness of weld SUS 447J1 metals, effect of ferrite content on aging toughness of weld austenitic stainless steel metal, corrosion morphology of welding zone of stainless steels, generation mechanism of knife line attack phenomenon, and corrosion potential of some kinds of metals in seawater at room temperature are illustrated. (S.Y.)

  9. The oxidation and reduction of chromium of stainless steels in an eletric arc furnace

    Directory of Open Access Journals (Sweden)

    B. Arh

    2011-07-01

    Full Text Available The oxidation of chromium during the elaboration of stainless steels occurs with oxygen in solution blown inthe melt and with oxides in the slag. A higher content of silicon in the furnace charge decreases the extent of oxidation of chromium, however, the efficient reduction of chromium from the slag is of essential importance for a minimal loss of chromium. In this survey, the theory of the oxidation of chromium, its reduction from the slag and the conditions for the formation of foaming slag are discussed.

  10. Study and development of solid fluxes for gas tungsten arc welding applied to titanium and its alloys and stainless steels

    International Nuclear Information System (INIS)

    Gas Tungsten Arc Welding uses an electric arc between the refractory tungsten electrode and the plates to be welded under an argon shielding gas. As a result, the joint quality is excellent, no pollution nor defects are to be feared, consequently this process is used in nuclear, aeronautic, chemical and food industries. Despite of this good qualities, GTAW is limited because of, on the one side, a poor penetrating weld pool and, on the other side, a week productivity rate. Indeed, up to 3 mm thick plates, machining and filler metal is needed. Multiple runs increase the defect's risks, the manufactory time and increase the deformations and the heat affected zone. The goal of this study is to break through this limits without any device investment. Active GTA welding (or ATIG) is a new technique with GTA device and an activating flux to be spread on the upper plate before welding. The arc, by plasma electrochemical equilibrium modifications, and the pool with the inner connective flows inversion, allow 7 mm thick joints in one run without edges machining or filler metal for both stainless steel and titanium alloys. This manuscript describes the development of these fluxes, highlights the several phenomena and presents the possibilities of this new process. This work, in collaboration with B.S.L. industries, leads to two flux formulations (stainless steel and titanium alloys) now in a commercial phase with CASTOLIN S.A. Moreover, B.S.L.industries produces a pressure device (nitrate column) with the ATIG process using more than 2800 ATIG welds. (author)

  11. A comparison of residual stresses in multi pass narrow gap laser welds and gas-tungsten arc welds in AISI 316L stainless steel

    OpenAIRE

    Elmesalamy, Ahmed; Francis, John Anthony; LI, Lin

    2014-01-01

    Thick-section austenitic stainless steels have widespread industrial applications, especially in nuclear power plants. The joining methods used in the nuclear industry are primarily based on arc welding processes. However, it has recently been shown that narrow gap laser welding (NGLW) can weld ma- terials with thicknesses that are well beyond the capabilities of single pass autogenous laser welding. The heat input for NGLW is much lower than for arc welding, as are the expected levels of res...

  12. Plasma arc welding of AISI316Ti (EN 1.4571) stainless steel. Mechanical, microstructural, corrosion aspects

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-01

    AISI316Ti (EN1.4571) austenitic stainless steel plates with a thickness of 7 mm were welded by plasma arc welding (PAW) process. Joints were obtained using 316L type of filler metal as well as without filler metal called as Weld 1 and Weld 2, respectively. Tensile and bend testing of the joints were carried out. Impact toughness tests carried out at temperatures from 20 C down to -60 C have shown encouraging results. Chemical analysis of the weld deposits were made by glow discharge optical emission spectrometry (GDOES). Photomacrographs and photomicrographs of the cross-sections were used to determine ferrite content and hardness. Intergranular corrosion tests in accordance with TSEN 3157/ENISO 3651-2 were carried out. No corrosion sign was reported. The effect of the consumable has the most influence on the toughness properties. Promising mechanical, toughness and corrosion results are useful, considering the implementation of an innovative process, thus PAW of 316Ti stainless steel. (orig.)

  13. Investigation of micro-structure and micro-hardness properties of 304L stainless steel treated in a hot cathode arc discharge plasma

    International Nuclear Information System (INIS)

    We have established a hot cathode arc discharge plasma system, where different stainless steel samples can be treated by monitoring the plasma parameters and nitriding parameters independently. In the present work, a mixture of 70% N2 and 30% H2 gases was fed into the plasma chamber and the treatment time and substrate temperature were optimized for treating 304L Stainless Steel samples. Various physical techniques such as x-ray diffraction, energy dispersive x-ray spectroscopy and micro-vickers hardness tester were employed to determine the structural, surface composition and surface hardness of the treated samples

  14. Investigation of micro-structure and micro-hardness properties of 304L stainless steel treated in a hot cathode arc discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Hitendra K., E-mail: hkmalik@physics.iitd.ac.in [Department of Physics, Indian Institute of Technology Delhi, New Delhi – 110016 (India); Singh, Omveer [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi – 110016 (India); Dahiya, Raj P. [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi – 110016 (India); Deenbandhu Chhotu Ram University of Science and Technology, Murthal–131039 (India)

    2015-08-28

    We have established a hot cathode arc discharge plasma system, where different stainless steel samples can be treated by monitoring the plasma parameters and nitriding parameters independently. In the present work, a mixture of 70% N{sub 2} and 30% H{sub 2} gases was fed into the plasma chamber and the treatment time and substrate temperature were optimized for treating 304L Stainless Steel samples. Various physical techniques such as x-ray diffraction, energy dispersive x-ray spectroscopy and micro-vickers hardness tester were employed to determine the structural, surface composition and surface hardness of the treated samples.

  15. Microstructural changes of a thermally aged stainless steel submerged arc weld overlay cladding of nuclear reactor pressure vessels

    International Nuclear Information System (INIS)

    The effect of thermal aging on microstructural changes in stainless steel submerged arc weld-overlay cladding of reactor pressure vessels was investigated using atom probe tomography (APT). In as-received materials subjected to post-welding heat treatments (PWHTs), with a subsequent furnace cooling, a slight fluctuation of the Cr concentration was observed due to spinodal decomposition in the δ-ferrite phase but not in the austenitic phase. Thermal aging at 400 °C for 10,000 h caused not only an increase in the amplitude of spinodal decomposition but also the precipitation of G phases with composition ratios of Ni:Si:Mn = 16:7:6 in the δ-ferrite phase. The degree of the spinodal decomposition in the submerged arc weld sample was similar to that in the electroslag weld one reported previously. We also observed a carbide on the γ-austenite and δ-ferrite interface. There were no Cr depleted zones around the carbide.

  16. Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

    Science.gov (United States)

    Rozenak, Paul; Unigovski, Yaakov; Shneck, Roni

    2016-05-01

    The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M23C6) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

  17. Submerged Arc Stainless Steel Strip Cladding—Effect of Post-Weld Heat Treatment on Thermal Fatigue Resistance

    Science.gov (United States)

    Kuo, I. C.; Chou, C. P.; Tseng, C. F.; Lee, I. K.

    2009-03-01

    Two types of martensitic stainless steel strips, PFB-132 and PFB-131S, were deposited on SS41 carbon steel substrate by a three-pass submerged arc cladding process. The effects of post-weld heat treatment (PWHT) on thermal fatigue resistance and hardness were evaluated by thermal fatigue and hardness testing, respectively. The weld metal microstructure was investigated by utilizing optical microscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). Results showed that, by increasing the PWHT temperature, hardness decreased but there was a simultaneous improvement in weldment thermal fatigue resistance. During tempering, carbide, such as (Fe, Cr)23C6, precipitated in the weld metals and molybdenum appeared to promote (Fe, Cr, Mo)23C6 formation. The precipitates of (Fe, Cr, Mo)23C6 revealed a face-centered cubic (FCC) structure with fine grains distributed in the microstructure, thereby effectively increasing thermal fatigue resistance. However, by adding nickel, the AC1 temperature decreased, causing a negative effect on thermal fatigue resistance.

  18. Fatigue of stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Solin, J. (VTT Technical Research Centre of Finland, Espoo (Finland))

    2010-05-15

    The 2009b update of ASME III introduces a new set of fatigue design curves. The new curve for austenitic stainless steels is exactly matching with the one endorsed in 2007 by the US NRC for new designs only. This has a notable effect in usage factor calculation at strain amplitudes below 0.5 %. However, experimental results clearly demonstrate that a new air curve would not be needed for the studied stainless steel grades. Our current results suggest arguments for use of stabilized stainless steels in NPP piping components, where high cycle fatigue (epsilon{sub a}<=0.5%) is a concern. (orig.)

  19. Shielding gas effects on flux cored arc welding of AISI 316L (N) austenitic stainless steel joints

    International Nuclear Information System (INIS)

    Highlights: ► The effects of shielding gasses are analyzed. ► The impact strength increases with increasing of percentage of CO2 in shielding gas mixtures. ► The ferrite percentage decreases with increasing of percentage of CO2 in shielding gas mixtures. ► Microhardness values increases with increasing of ferrite percentage in the weld metal. -- Abstract: This paper deals with the flux cored arc welding (FCAW) of AISI 316L (N) austenitic stainless steel with 1.2 mm diameter of flux cored 316LT filler wire. The welding was carried out with different shielding gas mixtures like 100% Ar, 95% Ar + 05% CO2, 90% Ar + 10% CO2, 80% Ar + 20% CO2, 75% Ar + 23% CO2 + 2% O2 and 70% Ar + 25% CO2 + 5% O2 and 100% CO2. The main aim of the work is to study the effect of various shielding gas mixtures on mechanical properties and metallurgical characters. The microstructures and ferrite content of the welds were analyzed. The mechanical characteristics such as impact test, microhardness and ductility of welds were carried out. The fracture surface impact samples were analyzed through scanning electron microscope (SEM). The fracture surface revealed a ductile rupture at room temperature and ductile rupture with a few cleavages at lower temperatures occurred. The toughness and ferrite percentages of the welds were decreased for increase of the CO2 in shielding gas mixtures.

  20. Phase transformations in welded supermartensitic stainless steels

    OpenAIRE

    Carrouge, Dominique

    2002-01-01

    Supermartensitic stainless steels have recently been introduced in the oil and gas industries to substitute more expensive duplex stainless steels for onshore and offshore tubing applications. Although easily joined by arc welding processes, the service life of the supermartensitic welded joint in corrosive environments relies to a large extent on the behaviour of the heat-affected zone (HAZ). The microstructure of the HAZ in these new materials has, until now, received little ...

  1. 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.

  2. Gravitational effects on weld pool shape and microstructural evolution during gas tungsten arc and laser beam welding on 304 stainless steel, nickel, and aluminum-4 wt.% copper alloy

    Science.gov (United States)

    Kang, Namhyun

    The objective of the present work was to investigate effects of gravitational (acceleration) level and orientation on Ni 200 alloy (99.5% Ni purity), 304 stainless steel, and Al-4 wt.% Cu alloy during gas tungsten arc welding (GTAW) and laser beam welding (LBW). Main characterization was focused on the weld pool shape, microstructure, and solute distribution as a function of gravitational level and orientation. The welds were divided into two classes, i.e., 'stable' and 'unstable' welds, in view of the variation of weld pool shape as a function of gravitational level and orientation. In general, higher arc current and translational GTAW produced more significant effects of gravitational orientation on the weld pool shape than the case of lower arc current and spot welding. Cross-sectional area (CSA) was a secondary factor in determining the stability of weld pool shape. For the 'stable' weld of 304 stainless steel GTAW, the II-U weld showed less convexity in the pool bottom and more depression of the free surface, therefore producing deeper penetration (10--20%) than the case of II-D weld. The II-D weld of 304 stainless steel showed 31% deeper penetration, 28% narrower width, and more hemispherical shape of the weld pool than the case of II-U weld. For GTAW on 304 stainless steel, gravitational level variation from low gravity (LG ≈ 1.2 go) to high gravity (HG ≈ 1.8 go) caused 10% increase in width and 10% decrease in depth while maintaining the overall weld pool volume. Furthermore, LBW on 304 stainless steels showed mostly constant shape of weld pool as a function of gravitational orientation. GTAW on Ni showed similar trends of weld pool shape compared with GTAW on 304 stainless steel, i.e., the weld pool became unstable by showing more penetration in the II-D weld for slower arc translational velocity (V a) and larger weld pool size. However, the Ni weld pool shape had greater stability of the weld pool shape with respect to the gravitational orientation

  3. Protection of Reinforced Concrete Structures of Waste Water Treatment Reservoirs with Stainless Steel Coating Using Arc Thermal Spraying Technique in Acidified Water

    Directory of Open Access Journals (Sweden)

    Han-Seung Lee

    2016-09-01

    Full Text Available Waste water treatment reservoirs are contaminated with many hazardous chemicals and acids. Reservoirs typically comprise concrete and reinforcement steel bars, and the main elements responsible for their deterioration are hazardous chemicals, acids, and ozone. Currently, a variety of techniques are being used to protect reservoirs from exposure to these elements. The most widely used techniques are stainless steel plating and polymeric coating. In this study, a technique known as arc thermal spraying was used. It is a more convenient and economical method for protecting both concrete and reinforcement steel bar from deterioration in waste water treatment reservoirs. In this study, 316L stainless steel coating was applied to a concrete surface, and different electrochemical experiments were performed to evaluate the performance of coatings in different acidic pH solutions. The coating generated from the arc thermal spraying process significantly protected the concrete surface from corrosion in acidic pH solutions, owing to the formation of a double layer capacitance—a mixture of Cr3+ enriched with Cr2O3 and Cr-hydroxide in inner and Fe3+ oxide on the outer layer of the coating. The formation of this passive film is defective owing to the non-homogeneous 316L stainless steel coating surface. In the pH 5 solution, the growth of a passive film is adequate due to the presence of un-dissociated water molecules in the aqueous sulfuric acid solution. The coated surface is sealed with alkyl epoxide, which acts as a barrier against the penetration of acidic solutions. This coating exhibits higher impedance values among the three studied acidic pH solutions.

  4. Application of Response Surface Methodolody to Prediction of Dilution in Plasma Transferred Arc Hardfacing of Stainless Steel on Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    V Balasubramanian; A K Lakshminarayanan; R Varahamoorthy; S Babu

    2009-01-01

    The application of.response surface methodology was highlighted to predict and optimize the percentage of dilution of iron-based hardfaced surface produced by the PTA (plasma transferred arc welding) process.The experiments were conducted based on five-factor five-level central composite rotatable design with full replication technique and a mathematical model was developed using response surface methodology.Furthermore,the response surface methodology was also used to optimize the process parameters that yielded the lowest percentage of dilution.

  5. A mathematical approach based on finite differences method for analyzing the temperature field in arc welding of stainless steel thin sheets

    International Nuclear Information System (INIS)

    This work develops a finite difference method to evaluate the temperature field in the heat affected zone in butt welding applied to AISI 304 stainless steel thin sheet by GTAW process. A computer program has been developed and implemented by Visual Basic for Applications (VBA) in MS-Excel spreadsheet. The results that are obtained using the numerical application foresee the thermal behaviour of arc welding processes. An experimental methodology has been developed to validate the mathematical model that allows to measure the temperature in several points close to the weld bead. The methodology is applied to a stainless steel sheet with a thickness lower than 3 mm, although may be used for other steels and welding processes as MIG/MAG and SMAW. The data which has been obtained from the experimental procedure have been used to validate the results that have been calculated by the finite differences numerical method. The mathematical model adjustment has been carried out taking into account the experimental results. The differences found between the experimental and theoretical approaches are due to the convection and radiation heat losses, which have not been considered in the simulation model.With this simple model, the designer will be able to calculate the thermal cycles that take place in the process as well as to predict the temperature field in the proximity of the weld bead. (Author). 18 refs.

  6. Tensile and Charpy impact behavior of an irradiated three-wire series-arc stainless steel cladding

    International Nuclear Information System (INIS)

    The potential for stainless steel cladding to improve the fracture behavior of an operating nuclear reactor pressure vessel, particularly during certain overcooling transients, may depend greatly on the properties of the irradiated cladding. Therefore, three-wire stainless steel cladding irradiated at temperatures and to fluences relevant to power reactor operation was examined. Postirradiation testing results show that, in the test temperature range from -125 to 288 degrees C, the yield strength increased by 8 to 30%, and ductility insignificantly increased, while there was almost no change in the ultimate tensile strength. All cladding exhibited ductile-to-brittle transition behavior during Charpy impact testing, owing to the dominance of delta-ferrite failures at low temperatures. On the upper shelf, the energy was reduced (owing to irradiation exposure) 15 to 20%, while the lateral expansion was reduced 43 and 41% at 2 and 5 - 1019 n/cm2 (E > 1 MeV), respectively. In addition, radiation damage resulted in 13 and 28 degrees C shifts of the Charpy impact transition temperature at the 41-J level for the low and high fluences, respectively

  7. Steam explosion triggering phenomena: stainless steel and corium-E simulants studied with a floodable arc melting apparatus. [BWR; PWR

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, L.S.; Buxton, L.D.

    1978-05-01

    Laboratory-scale experiments on the thermal interaction of light water reactor core materials with water have been performed. Samples (10--35 g) of Type 304 stainless steel and Corium-E simulants were each flooded with approximately 1.5 litres of water to determine whether steam explosions would occur naturally. Many of the experiments also employed artificially induced pressure transients in an attempt to initiate steam explosions. Vigorous interactions were not observed when the triggering pulse was not applied, and for stainless steel the triggering pulse initiated only coarse fragmentation. Two-stage, pressure-producing interactions were triggered for an ''oxidic'' Corium-E simulant. An impulse-initiated gas release theory has been simulated to explain the initial sample fragmentation. Although the delayed second stage of the event is not fully understood, it does not appear to be readily explained with classical vapor explosion theory. Rather, some form of metastability of the melt seems to be involved.

  8. 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.

  9. OPTIMIZATION OF PROCESS PARAMETERS TO MINIMIZE ANGULAR DISTORTION IN GAS TUNGSTEN ARC WELDED STAINLESS STEEL 202 GRADE PLATES USING PARTICLE SWARM OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    R. SUDHAKARAN

    2012-04-01

    Full Text Available This paper presents a study on optimization of process parameters using particle swarm optimization to minimize angular distortion in 202 grade stainless steel gas tungsten arc welded plates. Angular distortion is a major problem and most pronounced among different types of distortion in butt welded plates. The process control parameters chosen for the study are welding gun angle, welding speed, plate length, welding current and gas flow rate. The experiments were conducted using design of experiments technique with five factor five level central composite rotatable design with full replication technique. A mathematical model was developed correlating the process parameters with angular distortion. A source code was developed in MATLAB 7.6 to do the optimization. The optimal process parameters gave a value of 0.0305° for angular distortion which demonstrates the accuracy of the model developed. The results indicate that the optimized values for the process parameters are capable of producing weld with minimum distortion.

  10. Control of exposure to hexavalent chromium and ozone in gas metal arc welding of stainless steels by use of a secondary shield gas.

    Science.gov (United States)

    Dennis, John H; French, Michael J; Hewitt, Peter J; Mortazavi, Seyed B; Redding, Christopher A J

    2002-01-01

    Previous work has demonstrated that the shield gas composition in gas metal arc welding can have a considerable effect on hexavalent chromium [Cr(VI)] concentration in the fume and on ozone concentrations near the arc. Normally a single shield gas is used. This paper describes a double shroud torch that allows used of concentric shield gases of different compositions. A solid stainless steel wire was used for welding. The double shroud torch used secondary shield gases containing small amounts of the reducing agents NO and C2H4. The Cr(VI) concentration in the fume and ozone concentration at a fixed point relative to the arc were measured and compared with results when using a single shield gas. Use of the reducing agents in secondary shielding using the double shroud torch was found to offer advantages for ozone concentration reduction compared with use in a conventional torch, but this was not found to be an advantage for reducing Cr(VI) concentrations.

  11. A comparison of residual stresses in multi pass narrow gap laser welds and gas-tungsten arc welds in AISI 316L stainless steel

    International Nuclear Information System (INIS)

    Thick-section austenitic stainless steels have widespread industrial applications, especially in nuclear power plants. The joining methods used in the nuclear industry are primarily based on arc welding processes. However, it has recently been shown that narrow gap laser welding (NGLW) can weld materials with thicknesses that are well beyond the capabilities of single pass autogenous laser welding. The heat input for NGLW is much lower than for arc welding, as are the expected levels of residual stress and distortion. This paper reports on a preliminary investigation of the through-thickness 2D residual stresses distributions, distortions, and plastic strain characteristics, for the NGLW process using material thicknesses up to 20 mm. The results are compared with those obtained with gas-tungsten arc (GTA) welding. While further work is required on thicker test pieces, preliminary results suggest that the longitudinal tensile residual stresses in NGLW joints are 30–40% lower than those for GTA welds. -- Highlights: • The magnitude of the residual stresses is 30–40% lower in the Narrow Gap Laser Welds NGLW in comparison to those for GTA welding. • NGLW technique resulted in a very narrow tensile stress region. • The welding strategy has a significant influence on the induced residual stress for the NGLW technique. • The distortion angle of GTA welds is approximately 3 times higher than for NGLW. • The accumulation of plastic strain due to thermo-mechanical cycling in GTA welding is higher than for NGLW

  12. Stainless Steel Permeability

    Energy Technology Data Exchange (ETDEWEB)

    Buchenauer, Dean A. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Karnesky, Richard A. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States)

    2015-09-01

    An understanding of the behavior of hydrogen isotopes in materials is critical to predicting tritium transport in structural metals (at high pressure), estimating tritium losses during production (fission environment), and predicting in-vessel inventory for future fusion devices (plasma driven permeation). Current models often assume equilibrium diffusivity and solubility for a class of materials (e.g. stainless steels or aluminum alloys), neglecting trapping effects or, at best, considering a single population of trapping sites. Permeation and trapping studies of the particular castings and forgings enable greater confidence and reduced margins in the models. For FY15, we have continued our investigation of the role of ferrite in permeation for steels of interest to GTS, through measurements of the duplex steel 2507. We also initiated an investigation of the permeability in work hardened materials, to follow up on earlier observations of unusual permeability in a particular region of 304L forgings. Samples were prepared and characterized for ferrite content and coated with palladium to prevent oxidation. Issues with the poor reproducibility of measurements at low permeability were overcome, although the techniques in use are tedious. Funding through TPBAR and GTS were secured for a research grade quadrupole mass spectrometer (QMS) and replacement turbo pumps, which should improve the fidelity and throughput of measurements in FY16.

  13. Stainless steel display evaluation

    Science.gov (United States)

    Hopper, Darrel G.; Meyer, Frederick M.; Longo, Sam J.; Trissell, Terry L.

    2007-04-01

    Active matrix organic light emitting diode (AMOLED) technology is one candidate to become a low power alternative in some applications to the currently dominant, active matrix liquid crystal display (AMLCD), technology. Furthermore, fabrication of the AMOLED on stainless steel (SS) foil rather than the traditional glass substrate, while presenting a set of severe technical challenges, opens up the potential for displays that are both lighter and less breakable. Also, transition to an SS foil substrate may enable rollable displays - large when used but small for stowage within gear already worn or carried or installed. Research has been initiated on AMOLED/SS technology and the first 320 x 240 color pixel 4-in. demonstration device has been evaluated in the AFRL Display Test and Evaluation Laboratory. Results of this evaluation are reported along with a research roadmap.

  14. Weld bonding of stainless steel

    DEFF Research Database (Denmark)

    Santos, I. O.; Zhang, Wenqi; Goncalves, V.M.;

    2004-01-01

    This paper presents a comprehensive theoretical and experimental investigation of the weld bonding process with the purpose of evaluating its relative performance in case of joining stainless steel parts, against alternative solutions based on structural adhesives or conventional spot-welding. Th......This paper presents a comprehensive theoretical and experimental investigation of the weld bonding process with the purpose of evaluating its relative performance in case of joining stainless steel parts, against alternative solutions based on structural adhesives or conventional spot...

  15. Corrosion resistance improvement in Gas Tungsten Arc Welded 316L stainless steel joints through controlled preheat treatment

    International Nuclear Information System (INIS)

    Highlights: → Though the preheat treatment reduced the cooling rate, no sensitization occurred. → The delta ferrite content of welds reduced due to cooling retardment in welds. → Reduction in δ/γ boundaries was accompanied by decrement of passivation current. → Preheat treatment improved pitting resistance characteristics. → Increment of preheat temperature increased breakdown and repassivation potential. -- Abstract: In the present study, an attempt has been made to improve the corrosion characteristics of 316L stainless steel weldments through preheating at 450 oC and 650 oC. The infrared and Tungsten-Rhenium thermocouples were utilized to probe the cooling trend of heat affected zone (HAZ) and weld pool, respectively. X-ray diffraction (XRD) patterns, optical microscopy, electron microscopy, Energy Dispersion Spectroscopy (EDS) and ferritscope were also used to investigate the effect of preheating on microstructural characteristics within the weld and HAZ. Moreover, cyclic potentiodynamic test was carried out to evaluate the corrosion features of welds such as corrosion current, passivation current (IPP), breakdown potential (EB) and repassivation potential (Ere). Results revealed that preheating reduces the cooling rate of weld pool, accompanied by reduction of delta ferrite content of weldments. Moreover, it was observed that increment of preheat temperature improves corrosion behavior of weldments, including a lower passivation current and a more pitting resistance. These outcomes were mainly ascribed to decrease of austenite/delta ferrite interfaces as vulnerable sites to corrosion attacks, through preheat treatment. Observations showed no evidence of sensitization in preheated samples, which guaranteed the feasibility of suggested heat treatment.

  16. Strip casting of stainless steels

    OpenAIRE

    Raabe, D.

    1997-01-01

    FLAT PRODUCTS OF STAINLESS STEELS ARE CONVENTIONALLY MANUFACTURED BY CONTINUOUS CASTING, HOT ROLLING, HOT BAND ANNEALING, PICKLING, COLD ROLLING AND RECRYSTALLISATION. IN THE LAST YEARS STRIP CASTING HAS INCREASINGLY ATTRACTED ATTENTION. IT OFFERS THREE IMPROVEMENTS IN COMPARISON TO THE CONVENTIONAL METHOD.1.) IT ALLOWS TO CAST STEEL SHEETS WITH THE SAME THICKNESS AND WIDTH AS THOSE PRODUCED BY HOT ROLLING. THIS MEANS THAT THE HOT ROLLING PROCESSIS BYPASSED. 2.) THE STRIP CAST STEEL REVEALS A...

  17. Optimization of Process Parameters to Minimize Angular Distortion in Gas Tungsten Arc Welded Stainless Steel 202 Grade Plates Using Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Sudhakaran .R,

    2010-05-01

    Full Text Available This paper presents a study on optimization of process parameters using genetic algorithm to minimize angular distortion in 202 grade stainless steel gas tungsten arc welded plates. Angular distortion is a major problem and most pronounced among different types of distortion in butt welded plates. The extent of distortion depends onthe welding process control parameters. The important process control parameters chosen for study are gun angle (θ, welding speed (V, plate length (L, welding current (I and gas flow rate (Q. The experiments are conducted based on five factor five level central composite rotatable designs with full replication technique. A mathematical model was developed correlating the process parameters and the angular distortion. The developed model is checked for the adequacy based on ANOVA analysis and accuracy of prediction by confirmatory test. The optimization of process parameters was done using genetic algorithms (GA. A source code was developed using C language to do the optimization. The optimal process parameters gave a value of 0.000379° for angular distortion which demonstrates the accuracy and effectiveness of the model presented and program developed. The obtained results indicate that the optimized parameters are capable of producing weld with minimum distortion.

  18. 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.

  19. Annealing temperature effect on the pitting corrosion resistance of plasma arc welded joints of duplex stainless steel UNS S32304 in 1.0 M NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Tan Hua [Department of Materials Science, Fudan University, Shanghai 200433 (China); Wang Zhiyu [Research and Development Center, Baosteel Co., Ltd., Shanghai 201900 (China); Jiang Yiming; Han Dong; Hong Jufeng; Chen Lindou [Department of Materials Science, Fudan University, Shanghai 200433 (China); Jiang Laizhu [Research and Development Center, Baosteel Co., Ltd., Shanghai 201900 (China); Li Jin, E-mail: corrosion@fudan.edu.c [Department of Materials Science, Fudan University, Shanghai 200433 (China)

    2011-06-15

    Highlights: {yields} Welding, heat treatment, microstructure and pitting corrosion were studied. {yields} The weakest region of DSS welded joints was determined. {yields} The optimum annealing temperature for DSS welded joints was determined. {yields} Cause of degradation and improvement of pitting corrosion was analyzed. - Abstract: Pitting corrosion resistance of 2304 duplex stainless steels after autogenous plasma-arc welding and subsequent short-time post-weld heat treatment at different temperatures, determined by critical pitting temperature in 1.0 M NaCl solution, has been investigated. The results showed that the as-welded joint displayed impaired pitting corrosion resistance and that pitting preferentially occurred at ferrite grain in heat-affected zone near the fusion line. Short-time annealing treatment at 1020-1120 {sup o}C has a beneficial effect on the pitting corrosion resistance of welded joint. The most favorable annealing temperature for the analyzed welded joints was found to be 1080 {sup o}C, at which the joint restored the pitting corrosion resistance lost during welding entirely.

  20. Hybrid Laser-Arc Welding of 10-mm-Thick Cast Martensitic Stainless Steel CA6NM: As-Welded Microstructure and Mechanical Properties

    Science.gov (United States)

    Mirakhorli, Fatemeh; Cao, Xinjin; Pham, Xuan-Tan; Wanjara, Priti; Fihey, Jean-Luc

    2016-07-01

    Cast CA6NM martensitic stainless steel plates, 10 mm in thickness, were welded using hybrid laser-arc welding. The effect of different welding speeds on the as-welded joint integrity was characterized in terms of the weld bead geometry, defects, microstructure, hardness, ultimate tensile strength, and impact energy. Significant defects such as porosity, root humping, underfill, and excessive penetration were observed at a low welding speed (0.5 m/min). However, the underfill depth and excessive penetration in the joints manufactured at welding speeds above 0.75 m/min met the specifications of ISO 12932. Characterization of the as-welded microstructure revealed untempered martensite and residual delta ferrite dispersed at prior-austenite grain boundaries in the fusion zone. In addition, four different heat-affected zones in the weldments were differentiated through hardness mapping and inference from the Fe-Cr-Ni ternary phase diagram. The tensile fracture occurred in the base metal for all the samples and fractographic analysis showed that the crack path is within the martensite matrix, along primary delta ferrite-martensite interfaces and within the primary delta ferrite. Additionally, Charpy impact testing demonstrated slightly higher fracture energy values and deeper dimples on the fracture surface of the welds manufactured at higher welding speeds due to grain refinement and/or lower porosity.

  1. Influence of Mode of Metal Transfer on Microstructure and Mechanical Properties of Gas Metal Arc-Welded Modified Ferritic Stainless Steel

    Science.gov (United States)

    Mukherjee, Manidipto; Pal, Tapan Kumar

    2012-06-01

    This article describes in detail the effect of the modes of metal transfer on the microstructure and mechanical properties of gas metal arc-welded modified ferritic stainless steel (SSP 409M) sheets (as received) of 4 mm thickness. The welded joints were prepared under three modes of metal transfer, i.e., short-circuit (SC), spray (S), transfer, and mix (M) mode transfer using two different austenitic filler wires (308L and 316L) and shielding gas composition of Ar + 5 pct CO2. The welded joints were evaluated by means of microstructural, hardness, notched tensile strength, Charpy impact toughness, and high cycle fatigue. The dependence of weld metal microstructure on modes of metal transfer and filler wires has been determined by dilution calculation, WRC-1992 diagram, Creq/Nieq ratio, stacking fault energy (SFE), optical microscopy (OM), and transmission electron microscopy (TEM). It was observed that the microstructure as well as the tensile, Charpy impact, and high cycle fatigue of weld metal is significantly affected by the mode of metal transfer and filler wire used. However, the heat-affected zone (HAZ) is affected only by the modes of metal transfer. The results have been correlated with the microstructures of weld and HAZ developed under different modes of metal transfer.

  2. Preformed posterior stainless steel crowns: an update.

    Science.gov (United States)

    Croll, T P

    1999-02-01

    For almost 50 years, dentists have used stainless steel crowns for primary and permanent posterior teeth. No other type of restoration offers the convenience, low cost, durability, and reliability of such crowns when interim full-coronal coverage is required. Preformed stainless steel crowns have improved over the years. Better luting cements have been developed and different methods of crown manipulation have evolved. This article reviews stainless steel crown procedures for primary and permanent posterior teeth. Step-by-step placement of a primary molar stainless steel crown is documented and permanent molar stainless steel crown restoration is described. A method for repairing a worn-through crown also is reviewed.

  3. Parameters optimization of hybrid fiber laser-arc butt welding on 316L stainless steel using Kriging model and GA

    Science.gov (United States)

    Gao, Zhongmei; Shao, Xinyu; Jiang, Ping; Cao, Longchao; Zhou, Qi; Yue, Chen; Liu, Yang; Wang, Chunming

    2016-09-01

    It is of great significance to select appropriate welding process parameters for obtaining optimal weld geometry in hybrid laser-arc welding. An integrated optimization approach by combining Kriging model and GA is proposed to optimize process parameters. A four-factor, five-level experiment using Taguchi L25 is conducted considering laser power (P), welding current (A), distance between laser and arc (D) and traveling speed (V). Kriging model is adopted to approximate the relationship between process parameters and weld geometry, namely depth of penetration (DP), bead width (BW) and bead reinforcement (BR). The constructed Kriging model was used for parameters optimization by GA to maximize DP, minimize BW and ensure BR at a desired value. The effects of process parameters on weld geometry are analyzed. Microstructure and micro-hardness are also discussed. Verification experiments demonstrate that the obtained optimum values are in good agreement with experimental results.

  4. Corrosion behavior of 2205 duplex stainless steel.

    Science.gov (United States)

    Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

    1997-07-01

    The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires. PMID:9228844

  5. Stainless steel denitriding with slag

    International Nuclear Information System (INIS)

    Calculation and experimental methods were used to investigate the process of titanium nitride formation when alloying chromium nickel stainless steels with titanium. At common concentrations of titanium and nitrogen, titanium nitrides were observed to be precipitated from the melt into slag in amounts of 0.1% and more. The laboratory study of the slag influence of the process of steel refining from titanium nitrides showed that the slag containing calcium, aluminium and magnesium oxides is favourable to the denitriding of steel. In addition, the possibility of direct transition of dissolved nitrogen from the metal into the slag is revealed. 7 refs., 1 fig., 2 tabs

  6. The comparison of frictional resistance in titanium, self-ligating stainless steel, and stainless steel brackets using stainless steel and TMA archwires: An in vitro study

    OpenAIRE

    Syed Altaf Khalid; Vadivel Kumar; Prithviraj Jayaram

    2012-01-01

    Aim: The aim of the study was to compare the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and titanium molybdenum alloy (TMA) archwires. Materials and Methods: We compared the frictional resistance in 0.018 slot and 0.022 slot of the three brackets - titanium, self-ligating stainless steel, and conventional stainless steel - using stainless steel archwires and TMA archwires. An in vitro study of simulated ca...

  7. Microbial corrosion of stainless steel.

    Science.gov (United States)

    Ibars, J R; Moreno, D A; Ranninger, C

    1992-11-01

    Stainless steel, developed because of their greater resistance to corrosion in different aggressive environments, have proved to be affected, however, by various processes and types of corrosion. Some of these types of corrosion, mainly pitting, is activated and developed in the presence of microorganisms, which acting in an isolated or symbiotic way, according to their adaptation to the environment, create a favorable situation for the corrosion of these steel. The microorganisms that are involved, mainly bacteria of both the aerobic and anaerobic type, modify the environment where the stainless steel is found, creating crevices, differential aeration zones or a more aggressive environment with the presence of metabolites. In these circumstances, a local break of the passive and passivating layer is produced, which is proper to these types of steel and impedes the repassivation that is more favorable to corrosion. In the study and research of these types of microbiologically influenced corrosion are found electrochemical techniques, since corrosion is fundamentally an electrochemical process, and microbiological techniques for the identification, culture, and evaluation of the microorganisms involved in the process, as well as in the laboratory or field study of microorganism-metal pairs. Microstructural characterization studies of stainless steel have also been considered important, since it is known that the microstructure of steel can substantially modify their behavior when faced with corrosion. As for surface analysis studies, it is known that corrosion is a process that is generated on and progresses from the surface. The ways of dealing with microbiologically influenced corrosion must necessarily include biocides, which are not always usable or successful, the design of industrial equipment or components that do not favor the adherence of microorganisms, using microstructures in steel less sensitive to corrosion, or protecting the materials. PMID:1492953

  8. Nano-composite stainless steel

    Science.gov (United States)

    Dehoff, Ryan R.; Blue, Craig A.; Peter, William H.; Chen, Wei; Aprigliano, Louis F.

    2015-07-14

    A composite stainless steel composition is composed essentially of, in terms of wt. % ranges: 25 to 28 Cr; 11 to 13 Ni; 7 to 8 W; 3.5 to 4 Mo; 3 to 3.5 B; 2 to 2.5 Mn; 1 to 1.5 Si; 0.3 to 1.7 C; up to 2 O; balance Fe. The composition has an austenitic matrix phase and a particulate, crystalline dispersed phase.

  9. Hot workability of duplex stainless steels

    OpenAIRE

    Martin, Guilhem

    2011-01-01

    The Duplex Stainless Steels (DSS) are defined as a family of stainless steels consisting of a two-phase microstructure involving δ-ferrite and γ-austenite. Exceptional combinations of strength and toughness together with good corrosion resistance under critical working conditions designate DSS a suitable alternative to conventional austenitic stainless steels. Unfortunately, the relatively poor hot workability of these alloys makes the industrial processing of flat products particularly criti...

  10. Brazing of stainless steel; Stainless ko no rozuke

    Energy Technology Data Exchange (ETDEWEB)

    Matsu, T.

    1996-04-01

    This paper explains brazing of stainless steel as to its processing materials, brazing materials, brazing methods, and brazing works. When performing brazing at higher than 800{degree}C on a martensite-based stainless steel represented by the 13Cr steel, attention is required on cracking caused by quenching. When a ferrite-based stainless steel represented by the 18Cr steel is heated above 900{degree}C, crystalline particles grow coarser, causing their tenacity and corrosion resistance to decline. High-temperature long-time heating in brazing in a furnace demands cautions. Austenite-based stainless steel represented by the 18Cr-8Ni steel has the best brazing performance. However, since the steel has large thermal expansion coefficient and low thermal conductivity, attention is required on strain and deformation due to heating, and on localized overheating. Deposition hardened stainless steel made of the Cr-Ni alloy steel added with aluminum and titanium has poor wettability in a brazing work, hence pretreatment is required for the purpose of activation. 9 figs., 7 tabs.

  11. Interaction between stainless steel and plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    Dunwoody, John T [Los Alamos National Laboratory; Mason, Richard E [Los Alamos National Laboratory; Freibert, Franz J [Los Alamos National Laboratory; Willson, Stephen P [Los Alamos National Laboratory; Veirs, Douglas K [Los Alamos National Laboratory; Worl, Laura A [Los Alamos National Laboratory; Archuleta, Alonso [Los Alamos National Laboratory; Conger, Donald J [Los Alamos National Laboratory

    2010-01-01

    Long-term storage of excess plutonium is of great concern in the U.S. as well as abroad. The current accepted configuration involves intimate contact between the stored material and an iron-bearing container such as stainless steel. While many safety scenario studies have been conducted and used in the acceptance of stainless steel containers, little information is available on the physical interaction at elevated temperatures between certain forms of stored material and the container itself. The bulk of the safety studies has focused on the ability of a package to keep the primary stainless steel containment below the plutonium-iron eutectic temperature of approximately 410 C. However, the interactions of plutonium metal with stainless steel have been of continuing interest. This paper reports on a scoping study investigating the interaction between stainless steel and plutonium metal in a pseudo diffusion couple at temperatures above the eutectic melt-point.

  12. Fracture toughness of stainless steel welds

    International Nuclear Information System (INIS)

    The effects of temperature, composition and weld-process variations on the fracture toughness behavior for Types 308 and 16-8-2 stainless steel (SS) welds were examined using the multiple-specimen J/sub R/-curve procedure. Fracture characteristics were found to be dependent on temperature and weld process but not on filler material. Gas-tungsten-arc (GTA) welds exhibited the highest fracture toughness, a shielded metal-arc (SMA) weld exhibited an intermediate toughness and submerged-arc (SA) welds yielded the lowest toughness. Minimum-expected fracture properties were defined from lower-bound J/sub c/ and tearing modulus values generated here and in previous studies. Fractographic examination revealed that microvoid coalescence was the operative fracture mechanism for all welds. Second phase particles of manganese silicide were found to be detrimental to the ductile fracture behavior because they separated from the matrix during the initial stages of plastic straining. In SA welds, the high density of inclusions resulting from silicon pickup from the flux promoted premature dimple rupture. The weld produced by the SMA process contained substantially less manganese silicide, while GTA welds contained no silicide inclusions. Delta ferrite particles present in all welds were substantially more resistant to local failure than the silicide phase. In welds containing little or no manganese silicide, delta ferrite particles initiated microvoid coalescence but only after extensive plastic straining

  13. Optimization of the pulsed current gas tungsten arc welding (PCGTAW) parameters for corrosion resistance of super duplex stainless steel (UNS S32760) welds using the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Yousefieh, M., E-mail: m.yousefieh@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, M., E-mail: shamanian@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Saatchi, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-01-21

    Research highlights: > Among the four factors and three levels tested, it was concluded that the pulse current had the most significant effect on the pitting potential and the background current had the next most significant effect. The effects of pulse frequency and % on time are less important when compared to the other factors. > The percentage contributions of the pulse current, the background current, % on time, and pulse frequency to the corrosion resistance are 66.28%, 25.97%, 2.71% and 5.04%, respectively. > The optimum conditions within the selected parameter values were found as the second level of pulse current (120 A), second level of background current (60 A), third level of % on time (80%) and third level of pulse frequency (5 Hz). > The confirmation test was carried out at optimum working conditions. Pitting potential was increased to 1.06 V{sub SCE} by setting the control factors. Predicted (1.04 V{sub SCE}) and observed (1.06 V{sub SCE}) pitting potential values are close to each other, which are the highest values obtained in the present study. - Abstract: In the present work, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the pulsed current gas tungsten arc welding (PCGTAW) parameters for the corrosion resistance of super duplex stainless steel (UNS S32760) welds. A L{sub 9} (3{sup 4}) orthogonal array (OA) of Taguchi design which involves nine experiments for four parameters (pulse current, background current, % on time, pulse frequency) with three levels was used. Corrosion resistance in 3.5%NaCl solution was evaluated by anodic polarization tests at room temperature. Analysis of variance (ANOVA) is performed on the measured data and S/N (signal to noise) ratios. The higher the better response category was selected to obtain optimum conditions. The optimum conditions providing the highest pitting potential were estimated. The optimum conditions were found as the second level of pulse current (120 A

  14. Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints

    OpenAIRE

    J. Łabanowski

    2007-01-01

    Purpose: The aim of the current study is to reveal the influence of welding conditions on structure and stresscorrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Butt joints between duplex 2205 and austenitic 316L steels were performedwith the use of submerged arc welding (SAW) method. The plates 15 mm in thickness were welded with heatinput in the range of 1.15 – 3.2 kJ/mm using duplex steel filler metal. Microstructure examinations an...

  15. Duplex stainless steels for osteosynthesis devices.

    Science.gov (United States)

    Cigada, A; Rondelli, G; Vicentini, B; Giacomazzi, M; Roos, A

    1989-09-01

    The austenitic stainless steels used today for the manufacture of osteosynthesis devices are sensitive to crevice corrosion. In this study the corrosion properties of some duplex stainless steels were evaluated and compared to traditional austenitic stainless steels. According to our results the following ranking was established: 23Cr-4Ni less than AISI 316L less than ASTM F138 less than 22Cr-5Ni-3Mo less than 27Cr-31Ni-3.5Mo less than 25Cr-7Ni-4Mo-N. In particular the results showed that the high-performance 25Cr-7Ni-4Mo-N duplex stainless steel, with high molybdenum and nitrogen contents, can be considered not susceptible to crevice corrosion in the human body. The duplex stainless steels have also better mechanical properties at the same degree of cold working compared with austenitic stainless steels. Hence the 25Cr-7Ni-4Mo-N duplex stainless steel can be considered a convenient substitute of ASTM F138 for orthopedic and osteosynthesis devices. PMID:2777835

  16. Preparation of precursor for stainless steel foam

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiang-yang; LI Shan-ni; LI Jie; LIU Ye-xiang

    2008-01-01

    The effects of polyurethane sponge pretreatment and slurry compositions on the slurry loading in precursor were discussed, and the,performances of stainless steel foams prepared from precursors with different slurry loadings and different particle sizes of the stainless steel powder were also investigated. The experimental results show that the pretreatment of sponge with alkaline solution is effective to reduce the jam of cells in precursor and ensure the slurry to uniformly distribute in sponge, and it is also an effective method for increasing the slurry loading in precursor; the mass fraction of additive A and solid content in slurry greatly affect the slurry loading in precursor, when they are kept in 9%-13% and 52%-75%, respectively, the stainless steel foam may hold excellent 3D open-cell network structure and uniform muscles; the particle size of the stainless steel powder and the slurry loading in precursor have great effects on the bending strength, apparent density and open porosity of stainless steel foam; when the stainless steel powder with particle size of 44 tan and slurry loading of 0.5 g/cm3 in precursor are used, a stainless steel foam can be obtained, which has open porosity of 81.2%, bending strength of about 51.76 MPa and apparent density of about 1.0 g/cm3.

  17. Recycle of radiologically contaminated austenitic stainless steels

    International Nuclear Information System (INIS)

    The United States Department of Energy owns large quantities of radiologically contaminated austenitic stainless steel which could by recycled for reuse if appropriate release standards were in place. Unfortunately, current policy places the formulation of a release standard for USA industry years, if not decades, away. The Westinghouse Savannah River Company, Idaho National Engineering Laboratory and various university and industrial partners are participating in initiative to recycle previously contaminated austenitic stainless steels into containers for the storage and disposal of radioactive wastes. This paper describes laboratory scale experiments which demonstrated the decontamination and remelt of stainless steel which had been contaminated with radionuclides

  18. Hyperbaric welding of duplex stainless steel pipelines offshore.

    OpenAIRE

    Farrell, J.

    1996-01-01

    Three duplex stainless steels (Avesta 2205, Sandvik SAF2507 and Zeron 100) were successfully welded automatically at a range of pressures from 1 to 32bar. The gas tungsten arc (GTA) welding process was chosen as it allows a high degree of control to be exercised during welding. Initial autogenous bead on plate welds established the effects of pressure on the welding process and allowed the process parameters to be determined for subsequent experiments. Analysis of the eff...

  19. Gas tungsten arc welding of CP-copper to 304 stainless steel using different filler materials%焊丝对工业纯铜和304不锈钢钨极氩弧焊接的影响

    Institute of Scientific and Technical Information of China (English)

    Sajjad Gholami SHIRI; Mohsen NAZARZADEH; Mahmood SHARIFITABAR; Mehdi Shafiee AFARANI

    2012-01-01

    The dissimilar joining of CP-copper to 304 stainless steel was performed by gas tungsten arc welding process using different filler materials.The results indicated the formation of defect free joint by using copper filler material.But,the presence of some defects like solidification crack and lack of fusion caused decreasing tensile strength of other joints.In the optimum conditions,the tensile strength of the joint was 96% of the weaker material.Also,this joint was bent till to 180° without any macroscopic defects like separation,tearing or fracture.It was concluded that copper is a new and good candidate for gas tungsten arc welding of copper to 304 stainless steel.%采用不同焊丝对工业纯铜和304不锈钢进行钨极氩弧焊接.结果表明,采用铜做焊丝时,焊缝无任何缺陷生成,而采用304不锈钢和Ni-Cu-Fe合金为焊丝材料时,焊缝中有凝固裂纹和未熔化区存在.在最优条件下,焊缝的抗拉强度能达到铜材的96%.焊缝在弯曲到180°下也没有分离、撕裂和断裂等现象发生.这表明铜是一种较好的工业纯铜与304不锈钢GTA焊的焊丝材料.

  20. Stainless Steel to Titanium Bimetallic Transitions

    Energy Technology Data Exchange (ETDEWEB)

    Kaluzny, J. A. [Fermilab; Grimm, C. [Fermilab; Passarelli, D. [Fermilab

    2015-01-01

    In order to use stainless steel piping in an LCLS-II (Linac Coherent Light Source Upgrade) cryomodule, stainless steel to titanium bimetallic transitions are needed to connect the stainless steel piping to the titanium cavity helium vessel. Explosion bonded stainless steel to titanium transition pieces and bimetallic transition material samples have been tested. A sample transition tube was subjected to tests and x-ray examinations between tests. Samples of the bonded joint material were impact and tensile tested at room temperature as well as liquid helium temperature. The joint has been used successfully in horizontal tests of LCLS-II cavity helium vessels and is planned to be used in LCLS-II cryomodules. Results of material sample and transition tube tests will be presented.

  1. Hydrogen compatibility handbook for stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, G.R. Jr.

    1983-06-01

    This handbook compiles data on the effects of hydrogen on the mechanical properties of stainless steels and discusses this data within the context of current understanding of hydrogen compatibility of metals. All of the tabulated data derives from continuing studies of hydrogen effects on materials that have been conducted at the Savannah River Laboratory over the past fifteen years. Supplementary data from other sources are included in the discussion. Austenitic, ferritic, martensitic, and precipitation hardenable stainless steels have been studied. Damage caused by helium generated from decay of tritium is a distinctive effect that occurs in addition to the hydrogen isotopes protium and deuterium. The handbook defines the scope of our current knowledge of hydrogen effects in stainless steels and serves as a guide to selection of stainless steels for service in hydrogen.

  2. Horizontal electron beam welding for stainless steels

    International Nuclear Information System (INIS)

    Stainless steel samples have been realized by local vacuum apparatus for electron beam welding applications to reactor core shell realizations. The best welding parameters have been determined by a systematic study. The welds have been characterized by mechanical tests

  3. A Duplex Stainless Steel for Chloride Environments

    Science.gov (United States)

    Sridhar, N.; Kolts, J.; Flasche, L. H.

    1985-03-01

    This paper examines the effects of microstructural changes on the corrosion, stress corrosion cracking and corrosion fatigue resistance of a duplex stainless steel to chloride environments. The microstructural changes can be precipitation of phases such as sigma and carbides, or changes in the distribution of austenite and ferrite. The former can be important in hot forming operations while the latter is important in welding. The methods of minimizing these deleterious effects can sometimes be different from those used for austenitic stainless steel.

  4. Studies of stainless steel exposed to sandblasting

    OpenAIRE

    Horodek Paweł; Eseev Marat K.; Kobets Andrey G.

    2015-01-01

    The influence of sandblasting on surface and subsurface of stainless steel is investigated using variable energy positron beam (VEP), positron annihilation spectroscopy (PAS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Samples of stainless steel were blasted using 110 μm particles of Al2O3 under different pressure and time duration. In the case of sandblasting for 90 s, the reduction of positron diffusion length depending on the applied pressure was observed. Sandb...

  5. Fracture toughness properties of duplex stainless steels

    OpenAIRE

    Sieurin, Henrik

    2006-01-01

    Good toughness properties in base and weld material enable the use of duplex stainless steels (DSS) in critical applications. DSS offer high strength compared to common austenitic stainless steels. The high strength can be utilized to reduce the wall thickness and accordingly accomplish reduction of cost, welding time and transportation weight, contributing to ecological and energy savings. Although DSS have been used successfully in many applications the last decades, the full utilisation in...

  6. Research on the Submerged Arc Welding of Stainless Steel 06Cr19Ni10 and Steel Q235%不锈钢06Cr19Ni10和碳素钢Q235异种钢埋弧焊焊接工艺研究

    Institute of Scientific and Technical Information of China (English)

    杨丹丹; 王晓贞

    2013-01-01

    With regard to the submerged arc welding of dissimilar steels of stainless steel 06Cr19Ni10 and steel Q235-B,combining the structure characteristics of products and the welding property of two kinds of materials,welding process of two steels was explored and a welding procedure was determined.The problems of high production cost was solved.%根据生产过程中不锈钢06Cr19Ni10和碳素钢Q235-B异种钢板材的埋弧焊焊接问题,结合产品的结构特性和两种材料的焊接性,分析探索了异种钢材焊接的工艺方法,制定了切合实际生产的工艺方案,解决了生产成本高的难题.

  7. Stainless steel recycle FY94 progress report

    International Nuclear Information System (INIS)

    The Materials Technology Section (MTS) of the Savannah River Technology Center (SRTC) was asked to demonstrate the practicality of recycling previously contaminated stainless steel components such as reactor heat exchanger heads, process water piping and slug buckets into 208 liters (55 gallon) drums and 2.8 cubic meter (100 ft3) storage boxes. Radioactively contaminated stainless steel scrap will be sent to several industrial partners where it will be melted, decontaminated/cast into ingots, and rolled into plate and sheet and fabricated into the drums and boxes. As part of this recycle initiative, MTS was requested to demonstrate that radioactively contaminated Type 304L stainless steel could be remelted and cast to meet the applicable ASTM specification for fabrication of drums and boxes. In addition, MTS was requested to develop the technical basis of melt decontamination and establish practicality of using this approach for value added products. The findings presented in this investigation lead to the following conclusions: recycle of 18 wt% Cr-8 wt% Ni alloy can be achieved by melting Type 304 stainless steel in a air vacuum induction furnace; limited melt decontamination of the contaminated stainless steel was achieved, surface contamination was removed by standard decontamination techniques; carbon uptake in the as-cast ingots resulted from the graphite susceptor used in this experiment and is unavoidable with this furnace configuration. A new furnace optimized for melting stainless steel has been installed and is currently being tested for use in this program

  8. Mechanical properties and corrosion resistance of dissimilar stainless steel welds

    OpenAIRE

    J. Łabanowski

    2007-01-01

    Purpose: The purpose of this paper is to determine the influence of welding on microstructure, mechanical properties, and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Duplex 2205 and austenitic 316L steels were used. Butt joints of plates 15 mm in thickness were performed with the use of submerged arc welding (SAW) method. The heat input was in the range of 1.15 – 3.2 kJ/mm. Various plates’ edge preparation...

  9. High Mn austenitic stainless steel

    Science.gov (United States)

    Yamamoto, Yukinori [Oak Ridge, TN; Santella, Michael L [Knoxville, TN; Brady, Michael P [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Liu, Chain-tsuan [Knoxville, TN

    2010-07-13

    An austenitic stainless steel alloy includes, in weight percent: >4 to 15 Mn; 8 to 15 Ni; 14 to 16 Cr; 2.4 to 3 Al; 0.4 to 1 total of at least one of Nb and Ta; 0.05 to 0.2 C; 0.01 to 0.02 B; no more than 0.3 of combined Ti+V; up to 3 Mo; up to 3 Co; up to 1W; up to 3 Cu; up to 1 Si; up to 0.05 P; up to 1 total of at least one of Y, La, Ce, Hf, and Zr; less than 0.05 N; and base Fe, wherein the weight percent Fe is greater than the weight percent Ni, and wherein the alloy forms an external continuous scale including alumina, nanometer scale sized particles distributed throughout the microstructure, the particles including at least one of NbC and TaC, and a stable essentially single phase FCC austenitic matrix microstructure that is essentially delta-ferrite-free and essentially BCC-phase-free.

  10. Review on research and application of stainless steel reinforced concrete

    OpenAIRE

    Gu Li; Meng Xian Hong

    2016-01-01

    For ordinary reinforced under corrosion environment corrosion problems and analysis the main factors affecting ordinary steel corrosion, proposed stainless steel bar rust and corrosion resistance advantages, introduce the related properties of the stainless steel reinforced, combined with the research status of domestic and international stainless steel bar, put forward the research and engineering application of stainless steel rebar for the related problems and direction, the prospects and ...

  11. Radiation-induced sensitisation of stainless steels

    International Nuclear Information System (INIS)

    The book contains the proceedings of a symposium on radiation-induced sensitization of stainless steels, which took place at Berkeley, United Kingdom, 1986. The purpose of the symposium was to examine the mechanism leading to inter-granular corrosion of 20%Cr/25% Ni/Nb stainless steel cladding of AGR fuel following irradiation. Nine papers are presented, of which three are theoretical, two papers are based upon corrosion studies of 20%Cr/25%Ni/Nb steel, and the remaining are concerned with compositional redistribution and its measurement. (U.K.)

  12. The Effect of Welding Current and Composition of Stainless steel on the Panetration in GTAW

    OpenAIRE

    Ramazan Yılmaz; Turgay Tehçi

    2012-01-01

    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 ...

  13. Optimisation of welding procedures for duplex and superduplex stainless steels

    International Nuclear Information System (INIS)

    Austenitic stainless steels are increasingly being replaced by duplex grades that can offer similar corrosion resistance with far higher strength. This increased strength makes it possible to reduce material consumption whilst also decreasing transport and construction costs. Although established welding methods used for austenitic steels can be used for duplex steels, modification of the procedures can lead to improved results. This paper reviews the welding of duplex stainless steel and examines precautions that may be required. The advantages and disadvantages of different welding methods are highlighted and some high productivity solutions are presented. The application of a more efficient process with a high deposition rate (e.g. flux- cored arc welding) can decrease labour costs. Further close control of heat input and interpass temperature can result in more favourable microstructures and final properties. Although welding adversely affects the corrosion resistance of austenitic and duplex stainless steels, particularly the pitting resistance, relative to the parent material, this problem can be minimised by proper backing gas protection and subsequent pickling.

  14. Corrosion behavior of sensitized duplex stainless steel.

    Science.gov (United States)

    Torres, F J; Panyayong, W; Rogers, W; Velasquez-Plata, D; Oshida, Y; Moore, B K

    1998-01-01

    The present work investigates the corrosion behavior of 2205 duplex stainless steel in 0.9% NaCl solution after various heat-treatments, and compares it to that of 316L austenitic stainless steel. Both stainless steels were heat-treated at 500, 650, and 800 degrees C in air for 1 h, followed by furnace cooling. Each heat-treated sample was examined for their microstructures and Vickers micro-hardness, and subjected to the X-ray diffraction for the phase identification. Using potentiostatic polarization method, each heat-treated sample was corrosion-tested in 37 degrees C 0.9% NaCl solution to estimate its corrosion rate. It was found that simulated sensitization showed an adverse influence on both steels, indicating that corrosion rates increased by increasing the sensitization temperatures. PMID:9713683

  15. Copper contamination in thin stainless steel sheet

    International Nuclear Information System (INIS)

    The standard welding technique used at Oak Ridge Y-12 Plant for joining thin stainless sheet is the gas tungsten arc (GTA) welding process. One of the reoccurring problems with the sheet welds is surface cracking in the heat-affected zone (HAZ). Metallography shows that the cracks are only about 0.05 mm (0.002 in.) deep which is significant in a 0.25 mm (0.01 in.) thick sheet. Thus, welding requirements do not permit any surfacing cracking as detected by a fluorescent dye penetrant test conducted on every part after welding. Surface cracks have been found in both of the two most common weld designs in the thin sheet fabricated at the Oak Ridge Y-12 Plant. These butt joints are welded between two 0.25 mm thick stainless steel sheets and a tube with eyelet welded to a 25 mm (0.98 in.) thick sheet. The weld between the two sheets is made on a semiautomatic seam welding unit, whereas the tube-to-eyelet-to-sheet welds are done manually. The quality of both welds is very dependent on the welding procedure and the way the parts are placed in the weld fixturing. Metallographic examination has indicated that some welded parts with surface cracking in the weld region had copper particles on the surface, and the question of copper contamination has been raised. With the aid of a scanning electron microscope and an electron microprobe, the existence of copper in an around the surface cracks has been verified. The copper is on the surface of the parts prior to welding in the form of small dust particles

  16. Aging degradation of cast stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, O.K.; Chung, H.M.

    1985-10-01

    A program is being conducted to investigate the significance of in-service embrittlement of cast-duplex stainless steels under light-water reactor operating conditions. Data from room-temperature Charpy-impact tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 450/sup 0/C are presented and compared with results from other studies. Microstructures of cast-duplex stainless steels subjected to long-term aging either in the laboratory or in reactor service have been characterized. The results indicate that at least two processes contribute to the low-temperature embrittleent of duplex stainless steels, viz., weakening of the ferrite/austenite phase boundary by carbide precipitation and embrittlement of ferrite matrix by the formation of additional phases such as G-phase, Type X, or the ..cap alpha..' phase. Carbide precipitation has a significant effect on the onset of embrittlement of CF-8 and -8M grades of stainless steels aged at 400 or 450/sup 0/C. The existing correlations do not accurately represent the embrittlement behavior over the temperature range 300 to 450/sup 0/C. 18 refs., 13 figs.

  17. Aging degradation of cast stainless steel

    International Nuclear Information System (INIS)

    A program is being conducted to investigate the significance of in-service embrittlement of cast-duplex stainless steels under light-water reactor operating conditions. Data from room-temperature Charpy-impact tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 4500C are presented and compared with results from other studies. Microstructures of cast-duplex stainless steels subjected to long-term aging either in the laboratory or in reactor service have been characterized. The results indicate that at least two processes contribute to the low-temperature embrittleent of duplex stainless steels, viz., weakening of the ferrite/austenite phase boundary by carbide precipitation and embrittlement of ferrite matrix by the formation of additional phases such as G-phase, Type X, or the α' phase. Carbide precipitation has a significant effect on the onset of embrittlement of CF-8 and -8M grades of stainless steels aged at 400 or 4500C. The existing correlations do not accurately represent the embrittlement behavior over the temperature range 300 to 4500C. 18 refs., 13 figs

  18. Stress corrosion cracking susceptibility of dissimilar stainless steels welded joints

    Directory of Open Access Journals (Sweden)

    J. Łabanowski

    2007-01-01

    Full Text Available Purpose: The aim of the current study is to reveal the influence of welding conditions on structure and stresscorrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Butt joints between duplex 2205 and austenitic 316L steels were performedwith the use of submerged arc welding (SAW method. The plates 15 mm in thickness were welded with heatinput in the range of 1.15 – 3.2 kJ/mm using duplex steel filler metal. Microstructure examinations and corrosiontests were carried out. Slow strain rate tests (SSRT were performed in inert (glycerin and aggressive (boiling35% MgCl2 solution environments.Findings: It was shown that place of the lowest resistance to stress corrosion cracking is heat affected zone atduplex steel side of dissimilar joins. That phenomenon was connected with undesirable structure of that zoneconsisted of great amount of coarse ferrite grains and acicular austenite precipitates. High welding inputs do notdeteriorate stress corrosion cracking resistance of welds.Research limitations/implications: High welding heat inputs should enhance the precipitation process ofintermetallic phases in the HAZ. It is necessary to continue the research to determine the relationship betweenwelding parameters, obtained structures, and corrosion resistance of dissimilar stainless steels welded joints.Practical implications: Application of more productive joining process for dissimilar welds like submerged arcwelding instead of currently employed gas metal arc welding (GMAW method will be profitable in terms ofreduction the welding costs.Originality/value: The stress corrosion cracking resistance of dissimilar stainless steel welded joints wasdetermined. The zone of the weaker resistance to stress corrosion cracking was pointed out.

  19. HTPro: Low-temperature Surface Hardening of Stainless Steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2013-01-01

    Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance.......Low-temperature surface hardening of stainless steel provides the required performance properties without affecting corrosion resistance....

  20. Low temperature gaseous surface hardening of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present contribution gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular, the...

  1. Low temperature gaseous surface hardening of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present contribtion gives an overview of some of the technological aspects of low temperature thermochemical treatment of stainless steel. Examples of low temperature gaseous nitriding, carburising and nitrocarburising of stainless steel are presented and discussed. In particular, the...

  2. Ultrasonic Spectroscopy of Stainless Steel Sandwich Panels

    Science.gov (United States)

    Cosgriff, Laura M.; Lerch, Bradley A.; Hebsur, Mohan G.; Baaklini, George Y.; Ghosn, Louis J.

    2003-01-01

    Enhanced, lightweight material systems, such as 17-4PH stainless steel sandwich panels are being developed for use as fan blades and fan containment material systems for next generation engines. In order to improve the production for these systems, nondestructive evaluation (NDE) techniques, such as ultrasonic spectroscopy, are being utilized to evaluate the brazing quality between the 17-4PH stainless steel face plates and the 17-4PH stainless steel foam core. Based on NDE data, shear tests are performed on sections representing various levels of brazing quality from an initial batch of these sandwich structures. Metallographic characterization of brazing is done to corroborate NDE findings and the observed shear failure mechanisms.

  3. Phosphate coating on stainless steel 304 sensitized

    International Nuclear Information System (INIS)

    The stainless steel 304 can be sensitized when welding processes are applied, that causes the precipitation of chromium carbide in the grain limits, being promoted in this way the formation of galvanic cells and consequently the corrosion process. Using a phosphate coating is possible to retard the physiochemical damages that can to happen in the corrosion process. The stainless steel 304 substrate sensitized it is phosphate to base of Zn-Mn, in a immersion cell very hot. During the process was considered optimization values, for the characterization equipment of X-rays diffraction and scanning electron microscopy was used. The XRD technique confirmed the presence of the phases of manganese phosphate, zinc phosphate, as well as the phase of the stainless steel 304. When increasing the temperature from 60 to 90 C in the immersion process a homogeneous coating is obtained. (Author)

  4. Field welding of hydraulic turbines made of martensitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Akhtar, A.

    1982-06-15

    Field welding of hydraulic turbines made of 13 Cr-Ni martensitic stainless steels was investigated. Two shielded metal arc welding electrodes, one containing 15 Cr-25 Ni and the other with 50% cobalt, were studied with respect to the criteria of weldability, structural integrity and cavitation erosion resistance. The cavitation erosion resistance of the 15 Cr-25 Ni material, evaluated with an ultrasonic vibratory test method, was found to be poor, being comparable to that of mild steel. Although the 50% cobalt alloy possesses excellent cavitation erosion properties, its cost is ca 10 times higher than that of austenitic stainless steels. Under certain welding conditions, the 50% cobalt alloy produces a hard interface with the martensitic stainless steel base material. These interfaces were systematically investigated using microhardness measurement and scanning electron microscopy. The interfaces between the base metal and the weld deposits as well as that between the two weld metals were subjected to measurements of Charpy impact energy, corrosion fatigue tests and an elastoplastic fracture mechanics analysis. It is concluded that the presence of the hard zone is not detrimental to structural integrity. A field welding procedure is proposed on the basis of these findings. The shallow cavitation damaged areas may be repaired with the 50% cobalt containing material. The cheaper 15 Cr-25 Ni material may be used for the filling of deep cavitation damaged areas and for the repair of cracks followed by an overlay of 50% cobalt weld metal. 20 refs., 22 figs., 7 tabs.

  5. Initial oxidation of duplex stainless steel 2205

    Energy Technology Data Exchange (ETDEWEB)

    Donik, E.; Kocijan, A.; Jenko, M. [Institute of metals and technology, Ljubljana (Slovenia)

    2009-07-01

    Due to superior mechanical and corrosion properties of duplex stainless steels which result in weight reduction of the constructions, thus contributing to the decreases in total costs and also due to the large and versatile usage of the alloy, duplex stainless steel is gradually displacing stainless steels of the AISI 300 series. Pickling of duplex stainless steel has proven to be much more difficult than that of standard austenitic grade (AISI 300 series). There is no complete agreement in the literature on scale (high temperature oxidation) dissolution mechanism in neutral pickling solutions. During annealing, duplex stainless steel is heated in annealing furnace up to 1050 C and is kept at this temperature for some time to soften the metal in order to release the work hardening induced by hot and cold rolling. The elimination of surface defects by forming the oxide scale is required to improve the corrosion resistance. Three different techniques were used to produce thin oxide layers on polished and sputter cleaned duplex stainless steel samples. They were exposed to 10{sup -5} mb pure oxygen inside the vacuum chamber, exposed to ambient conditions for 24 hours and plasma oxidized. Oxide layers thus produced were analysed using XPS depth profiling for determination of the oxide layer's composition with depth. It was found that all techniques produce oxide layer with different traces of metallic components and with chromium oxide maximum concentration shifted towards the oxide layer - bulk metal interface. Depletion of Cr in bulk immediately below the interface was also observed. Simplified ARXPS procedure was used to corroborate thickness estimates for thinnest oxide layers. (authors)

  6. Stainless Steel Microstructure and Mechanical Properties Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan T

    2010-06-01

    A nitrogen strengthened 21-6-9 stainless steel plate was spinformed into hemispherical test shapes. A battery of laboratory tests was used to characterize the hemispheres. The laboratory tests show that near the pole (axis) of a spinformed hemisphere the yield strength is the lowest because this area endures the least “cold-work” strengthening, i.e., the least deformation. The characterization indicated that stress-relief annealing spinformed stainless steel hemispheres does not degrade mechanical properties. Stress-relief annealing reduces residual stresses while maintaining relatively high mechanical properties. Full annealing completely eliminates residual stresses, but reduces yield strength by about 30%.

  7. Measuring secondary phases in duplex stainless steels

    Science.gov (United States)

    Calliari, I.; Brunelli, K.; Dabalà, M.; Ramous, E.

    2009-01-01

    The use of duplex stainless steels is limited by their susceptibility to the formation of dangerous intermetallic phases resulting in detrimental effects on impact toughness and corrosion resistance. This precipitation and the quantitative determinations of the phases have received considerable attention and different precipitation sequences (σ phase, χ phase, and carbides) have been suggested. This study investigates the phase transformation during continuous cooling and isothermal treatments in commercial duplex stainless steel grades and the effects on alloy properties, and compares the most common techniques of analysis.

  8. Embrittlement of austenitic stainless steel welds

    International Nuclear Information System (INIS)

    To prevent hot-cracking, austenitic stainless steel welds generally contain a small percent of delta ferrite. Although ferrite has been found to effectively prevent hot-cracking, it can lead to embrittlement of welds when exposed to elevated temperatures. The aging behavior of type-308 stainless steel weld has been examined over a range of temperatures 475--850 C for times up to 10,000 hrs. Upon aging, and depending on the temperature range, the unstable ferrite may undergo a variety of solid state transformations. These phase changes creep-rupture and Charpy impact properties

  9. 21 CFR 878.4495 - Stainless steel suture.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stainless steel suture. 878.4495 Section 878.4495...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4495 Stainless steel suture. (a) Identification. A stainless steel suture is a needled or unneedled nonabsorbable surgical suture composed of...

  10. 21 CFR 872.3350 - Gold or stainless steel cusp.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or...

  11. Optimization of welding variables for duplex stainless steel by GTAW and SMAW

    International Nuclear Information System (INIS)

    The main problems faced during the welding of duplex stainless steels are cleanliness and slag inclusions. In the present work the methods to eliminate these problems were studied during the welding of duplex stainless steel by Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW). Since the duplex stainless steel is an expensive material, the initial experiments for optimization of welding variables were. carried out on low carbon steel (CS) plates with duplex consumables. Welding of butt groove joints on CS plates was carried with various sets of welding variables i.e. current, voltage and arc energy using duplex consumables. The. radiographic inspection, micro-structural observations and hardness testing of the welds suggested the welding variables that will produce a sound weld on CS plate. These optimized variables were then used for the welding of edge groove joint and T -joint on duplex stainless steel by GTAW and SMAW processes. The hardness and micro-structural study of the joints produced on duplex stainless steel by GTAW and SMAW with duplex consumables were also studied. No slag inclusions and porosity were observed in the microstructure of these weldments and their properties were found similar to the parent metal. (author)

  12. Nickel-free austenitic stainless steels for medical applications

    Directory of Open Access Journals (Sweden)

    Ke Yang and Yibin Ren

    2010-01-01

    Full Text Available The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength and good plasticity, better corrosion and wear resistances, and superior biocompatibility compared to the currently used 316L stainless steel, the newly developed high-nitrogen nickel-free stainless steel is a reliable substitute for the conventional medical stainless steels.

  13. Stainless chromium-nickel steels. Chapter I

    International Nuclear Information System (INIS)

    The chemical composition is tabulated of 90 chromium-nickel stainless steels and alloys given in volume %. The values are also given of the corrosion resistance of the steels and alloys. The tables show data on the surface condition or the methods of material working, types and chemical composition of the medium where corrosion resistance tests were carried out, temperature, pressure, time of tests, corrosion rates, corrosion types, and literature references. A total of 35 references is given. (J.B.)

  14. A study on laser welding deformation of 304 stainless steel

    International Nuclear Information System (INIS)

    In heavy industries, 304 austenitic stainless steel is the most popular material which is used for nuclear equipment, chemical vessels, vacuum vessels and so on. On the fabrication, not only a joint quality but also severe dimensional accuracy is required. To keep dimensional accuracy, considerable cost and efforts are requested, because the welding deformation of austenitic stainless steel is deeply depended on the physical properties of material itself. To decrease welding deformation, big jigs or water cooling method are commonly used which lead to the high cost. In general, the fusion welding by high energy density heat source results in less distortion. Today, laser welding technology has grown up to the stage that enables to weld thick plate with small deformation. The researches of welding deformation have been conducted intensively, but they are mainly concerned for arc welding, and studies for laser welding are very few. In this report, the authors will show the test results of deformation behavior in laser welding of 304 stainless steel. Also, they will discuss the deformation behavior comparing to that in arc welding. The main results of this study are as follows. 1. The angular distortion of laser welding can be unified by heat input parameter (Hp) which is used for arc welding deformation. 2. The angular distortion are same under the condition of Hp3 in spite of different welding method, however under the condition of Hp>6-9 J/mm3 the angular distortion is quite different depending on the power density of welding method. 3. Pure angular distortion seemed to complete just after welding, but following longitudinal distortion took place for long period. 4. The critical value of longitudinal distortion can be estimated from heat input parameter. The transverse deformation can be also estimated by heat input parameter. (author)

  15. Evaluation of weld defects in stainless steel 316L pipe using guided wave

    International Nuclear Information System (INIS)

    Stainless steel is a popular structural materials for liquid-hydrogen storage containers and piping components for transporting high-temperature fluids because of its superior material properties such as high strength and high corrosion resistance at elevated temperatures. In general, tungsten inert gas (TIG) arc welding is used for bonding stainless steel. However, it is often reported that the thermal fatigue cracks or initial defects in stainless steel after welding decreases the reliability of the material. The objective of this paper is to clarify the characteristics of ultrasonic guided wave propagation in relation to a change in the initial crack length in the welding zone of stainless steel. For this purpose, three specimens with different artificial defects of 5 mm, 10 mm, and 20 mm in stainless steel welds were prepared. By considering the thickness of s stainless steel pipe, special attention was given to both the L(0,1) mode and L(0,2) mode in this study. It was clearly found that the L(0,2) mode was more sensitive to defects than the L(0,1) mode. Based on the results of the L(0,1) and L(0,2) mode analyses, the magnitude ratio of the two modes was more effective than studying each mode when evaluating defects near the welded zone of stainless steel because of its linear relationship with the length of the artificial defect.

  16. Evaluation of weld defects in stainless steel 316L pipe using guided wave

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joon Hyun [School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of); Lee, Jin Kyung [Dept. of Mechanical Engineering, Dongeui University, Busan (Korea, Republic of)

    2015-02-15

    Stainless steel is a popular structural materials for liquid-hydrogen storage containers and piping components for transporting high-temperature fluids because of its superior material properties such as high strength and high corrosion resistance at elevated temperatures. In general, tungsten inert gas (TIG) arc welding is used for bonding stainless steel. However, it is often reported that the thermal fatigue cracks or initial defects in stainless steel after welding decreases the reliability of the material. The objective of this paper is to clarify the characteristics of ultrasonic guided wave propagation in relation to a change in the initial crack length in the welding zone of stainless steel. For this purpose, three specimens with different artificial defects of 5 mm, 10 mm, and 20 mm in stainless steel welds were prepared. By considering the thickness of s stainless steel pipe, special attention was given to both the L(0,1) mode and L(0,2) mode in this study. It was clearly found that the L(0,2) mode was more sensitive to defects than the L(0,1) mode. Based on the results of the L(0,1) and L(0,2) mode analyses, the magnitude ratio of the two modes was more effective than studying each mode when evaluating defects near the welded zone of stainless steel because of its linear relationship with the length of the artificial defect.

  17. Advances in the research of nitrogen containing stainless steels

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    The current status of nitrogen containing stainless steels at home and aboard has been introduced. The function and existing forms of nitrogen in the stainless steels, influence of nitrogen on mechanical properties and anti-corrosion properties as well as the application of nitrogen containing cast stainless steels were discussed in this paper. It is clear that nitrogen will be a potential and important alloying element in stainless steels. And Argon Oxygen Decarbonization (AOD) refining can provide an advanced manufacture process for nitrogen containing stainless steels with ultra-low- carbon and high cleanliness.

  18. Sintering and characterization of YAG dispersed ferritic stainless steels

    International Nuclear Information System (INIS)

    The present study investigates the effect of yttrium aluminium garnet (YAG) addition on the densification, mechanical, tribological and corrosion behaviour of ferritic (434L) stainless steels. The composites were sintered at both solid-state (1200 deg. C) and supersolidus (1400 deg. C) sintering conditions. Supersolidus sintering results in superior densification, hardness and corrosion resistance of both straight 434L stainless steel as well as YAG reinforced 434L stainless steels. The addition of YAG to 434L stainless steels at supersolidus sintered conditions improves the strength and wear resistance of 434L stainless steels without significantly degrading the corrosion performance

  19. Stainless steel forgings for nuclear chemical plants

    International Nuclear Information System (INIS)

    This Specification covers detailed requirements for the supply of austenitic stainless steel forgings used in radioactive and corrosive areas within the Nuclear Industry. With the exception of 316S51 the materials specified are all suitable for contact with nitric acid, 316S51 being included as suitable for use in contact with sodium and other alkali metals at elevated temperatures. (author)

  20. CASE-HARDENING OF STAINLESS STEEL

    DEFF Research Database (Denmark)

    2004-01-01

    The invention relates to case-hardening of a stainless steel article by means of gas including carbon and/or nitrogen, whereby carbon and/or nitrogen atoms diffuse through the surface into the article. The method includes activating the surface of the article, applying a top layer on the activated...

  1. Austenitic stainless steels for cryogenic service

    Energy Technology Data Exchange (ETDEWEB)

    Dalder, E.N.C.; Juhas, M.C.

    1985-09-19

    Presently available information on austenitic Fe-Cr-Ni stainless steel plate, welds, and castings for service below 77 K are reviewed with the intent (1) of developing systematic relationships between mechanical properties, composition, microstructure, and processing, and (2) of assessing the adequacy of these data bases in the design, fabrication, and operation of engineering systems at 4 K.

  2. Stabilizing stainless steel components for cryogenic service

    Science.gov (United States)

    Holden, C. F.

    1967-01-01

    Warpage and creep in stainless steel valve components are decreased by a procedure in which components are machined to a semifinish and then cold soaked in a bath of cryogenic liquid. After the treatment they are returned to ambient temperature and machine finished to the final drawing dimensions.

  3. Hydrogen gas embrittlement of selected stainless steels

    International Nuclear Information System (INIS)

    Hydrogen gas embrittlement of selected stainless steels: metastable 18-8, (α+γ) IN 744 and γ' or N-hardened austenites, has been investigated means of the triaxial disk pressure test at various pressure increase rates, at RT or sometimes -500C and +1000C. Test are supplemented with SEM and magnetic phase determination

  4. Ne Implantation Induced Transformation in Stainless Steel

    NARCIS (Netherlands)

    Noordhuis, J.; Hosson, J.Th.M. De

    1990-01-01

    This paper reports a microstructural investigation of the changes induced by Ne implantation in stainless steel of the austenitic type. At a critical dose of 2.3 · 10^17/cm^2 a martensitic phase transformation was observed. In particular, attention has been paid to the effect of the stress held of n

  5. Microbially Influenced Corrosion of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Deuk; Ryu, Seung Ki; Kim Young Ho [POSCO Techanical Researh Laboratories, Pohang (Korea, Republic of)

    1996-06-25

    Microbially Influenced Corrosion(MIC) is often a significant factor in controlling the long-term performance of most structural materials in industrial applications. This papers cover MIC mechanism and evaluation of stainless steels in soil and sea water environments. Papers also cover detection, monitoring and mitigation of MIC, biocides and treatments. (author). 28 refs., 2 tabs., 5 figs.

  6. Austenitic stainless steels for cryogenic service

    International Nuclear Information System (INIS)

    Presently available information on austenitic Fe-Cr-Ni stainless steel plate, welds, and castings for service below 77 K are reviewed with the intent (1) of developing systematic relationships between mechanical properties, composition, microstructure, and processing, and (2) of assessing the adequacy of these data bases in the design, fabrication, and operation of engineering systems at 4 K

  7. Granulate of stainless steel as compensator material

    NARCIS (Netherlands)

    J.P.C. van Santvoort (J. P C)

    1995-01-01

    textabstractCompensators produced with computer controlled milling devices usually consist of a styrofoam mould, filled with an appropriate material. We investigated granulate of stainless steel as filling material. This cheap, easy to use, clean and re-usable material can be obtained with an averag

  8. Hybrid Laser-Arc Welding Tanks Steels

    Science.gov (United States)

    Turichin, G.; Tsibulskiy, I.; Kuznetsov, M.; Akhmetov, A.; Klimova-Korsmik, O.

    2016-04-01

    The results investigate hybrid laser-arc welding of high strength steels using design responsible metallic construction and the highest strength body of vehicles. Welds from modern high strength steels grade Hardox 400, Hardox 450, Armox 600T and AB were created. High power fiber laser LS-15 with output 15 kW and arc rectifier VDU - 1500 DC were used in the experiment. Results of the metallographic research and mechanical tests are presented.

  9. Aging degradation of cast stainless steel

    International Nuclear Information System (INIS)

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. Microstructures of cast materials subjected to long-term aging either in reactor service or in the laboratory have been characterized by TEM, SANS, and APFIM techniques. Two precipitate phases, i.e., the Cr-rich α' and Ni- and Si-rich G phase, have been identified in the ferrite matrix of the aged steels. The results indicate that the low-temperature embrittlement is primarily caused by α' precipitates which form by spinodal decomposition. The relative contribution of G phase to loss of toughness is now known. Microstructural data also indicate that weakening of ferrite/austenite phase boundary by carbide precipitates has a significant effect on the onset and extent of embrittlement of the high-carbon CF-8 and CF-8M grades of stainless steels, particularly after aging at 400 or 4500C. Data from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 4500C are presented and correlated with the microstructural results. Thermal aging of the steels results in an increase in tensile strength and a decrease in impact energy, J/sub IC/, and tearing modulus. The fracture toughness results show good agreement with the Charpy-impact data. The effects of compositional and metallurgical variables on loss of toughness are discussed

  10. Austenitic stainless steels with cryogenic resistance

    International Nuclear Information System (INIS)

    The most used austenitic stainless steels are alloyed with chromium and nickel and have a reduced carbon content, usually lower than 0.1 % what ensures corresponding properties for processing by plastic deformation at welding, corrosion resistance in aggressive environment and toughness at low temperatures. Steels of this kind alloyed with manganese are also used to reduce the nickel content. By alloying with manganese which is a gammageneous element one ensures the stability of austenites. Being cheaper these steels may be used extensively for components and equipment used in cryogenics field. The best results were obtained with steels of second group, AMnNi, in which the designed chemical composition was achieved, i.e. the partial replacement of nickel by manganese ensured the toughness at cryogenic temperatures. If these steels are supplementary alloyed, their strength properties may increase to the detriment of plasticity and toughness, although the cryogenic character is preserved

  11. Nickel-free austenitic stainless steels for medical applications

    OpenAIRE

    Ke Yang and Yibin Ren

    2010-01-01

    The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainl...

  12. Effects of irradiation on the fracture properties of stainless steel weld overlay cladding

    International Nuclear Information System (INIS)

    Stainless steel weld overlay cladding was fabricated using the submerged arc, single-wire, oscillating-electrode, and the three-wire, series-arc methods. Three layers of cladding were applied to a pressure vessel plate to provide adequate thickness for fabrication of test specimens, and irradiations were conducted at temperatures and to fluences relevant to power reactor operation. For the first single-wire method, the first layer was type 309, and the upper two layers were type 308 stainless steel. The type 309 was diluted considerably by excessive melting of the base plate. The three-wire method used various combinations of types 308, 309, and 304 stainless steel weld wires, and produced a highly controlled weld chemistry, microstructure, and fracture properties in all three layers of the weld. 14 refs., 15 figs., 4 tabs

  13. Tensile-property characterization of thermally aged cast stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K. [Argonne National Lab., IL (United States)

    1994-02-01

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

  14. Joining dissimilar stainless steels for pressure vessel components

    International Nuclear Information System (INIS)

    A series of studies was carried out to examine the weldability and properties of dissimilar steel joints between martensitic and austenitic stainless steels - F6NM (OCrl3Ni4Mo) and AISI 347, respectively. The weldability tests included weld thermal simulation of the martensitic steel for investigating the influence of weld thermal cycles and post-weld heat treatment (PWHT) on the mechanical properties of the heat-affected zone (HAZ); implant testing for examining the tendency for cold cracking of martensitic steel; rigid restraint testing for determining hot crack susceptibility of the multi-pass dissimilar steel joints. The joints were subjected to various mechanical tests including a tensile test, bending test and impact test at various temperatures, as well as slow strain-rate test for examining the stress corrosion cracking tendency in the simulated environment of a primary circuit of a PWR. Based on the weldability tests, a welding procedure - tungsten inert gas (TIG) welding for root passes with HNiCrMo-2B wire followed by manual metal arc (MMA) welding using coated electrode ENiCrFe-3B - was developed and a PWHT at 600 deg C/2h was recommended. Furthermore, the welding of tube/tube joints between these dissimilar steels is described. (21 refs., 11 figs., 14 tabs.)

  15. Phase Transformation in Cast Superaustenitic Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Lee Phillips, Nathaniel Steven [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Superaustenitic stainless steels constitute a group of Fe-based alloys that are compositionally balanced to have a purely austenitic matrix and exhibit favorable pitting and crevice corrosion resistant properties and mechanical strength. However, intermetallic precipitates such as sigma and Laves can form during casting or exposure to high-temperature processing, which degrade the corrosion and mechanical properties of the material. The goal of this study was to accurately characterize the solid-solid phase transformations seen in cast superaustenitic stainless steels. Heat treatments were performed to understand the time and temperature ranges for intermetallic phase formations in alloys CN3MN and CK3MCuN. Microstructures were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy and wavelength dispersive spectroscopy (EDS, WDS). The equilibrium microstructures, composed primarily of sigma and Laves within purely austenitic matrices, showed slow transformation kinetics. Factors that determine the extent of transformation, including diffusion, nucleation, and growth, are discussed.

  16. Plasma spot welding of ferritic stainless steels

    International Nuclear Information System (INIS)

    Plasma spot wedding of ferritic stainless steels studied. The study was focused on welding parameters, plasma and shieldings and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas , i. e. a 98% Ar/2% H2 gas mixture. Tension-shear strength of plasma-spot welded joint was compared to that of resistance sport welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a large weld sport diameter of the former. Strength of both types of welded joints is approximately the same. (Author) 32 refs

  17. Studies of stainless steel exposed to sandblasting

    Directory of Open Access Journals (Sweden)

    Horodek Paweł

    2015-12-01

    Full Text Available The influence of sandblasting on surface and subsurface of stainless steel is investigated using variable energy positron beam (VEP, positron annihilation spectroscopy (PAS, scanning electron microscopy (SEM, and atomic force microscopy (AFM. Samples of stainless steel were blasted using 110 μm particles of Al2O3 under different pressure and time duration. In the case of sandblasting for 90 s, the reduction of positron diffusion length depending on the applied pressure was observed. Sandblasting during 30 s leads only to the reduction of positron diffusion length to about 60 nm for all samples. Positron lifetimes close to 170 ps measured using positrons emitted directly from the source point to the presence of vacancies on the dislocation lines. SEM and AFM images show that surface roughness depends rather on pressure of sandblasting than time of exposition.

  18. Weldability of Additive Manufactured Stainless Steel

    Science.gov (United States)

    Matilainen, Ville-Pekka; Pekkarinen, Joonas; Salminen, Antti

    Part size in additive manufacturing is limited by the size of building area of AM equipment. Occasionally, larger constructions that AM machines are able to produce, are needed, and this creates demand for welding AM parts together. However there is very little information on welding of additive manufactured stainless steels. The aim of this study was to investigate the weldability aspects of AM material. In this study, comparison of the bead on plate welds between AM parts and sheet metal parts is done. Used material was 316L stainless steel, AM and sheet metal, and parts were welded with laser welding. Weld quality was evaluated visually from macroscopic images. Results show that there are certain differences in the welds in AM parts compared to the welds in sheet metal parts. Differences were found in penetration depths and in type of welding defects. Nevertheless, this study presents that laser welding is suitable process for welding AM parts.

  19. Tritium Depth Profiles in 316 Stainless Steel

    Science.gov (United States)

    Torikai, Yuji; Murata, Daiju; Penzhorn, Ralf-Dieter; Akaishi, Kenya; Watanabe, Kuniaki; Matsuyama, Masao

    To investigate the behavior of hydrogen uptake and release by 316 stainless steel (SS316), as-received and finely polished stainless steel specimens were exposed at 573 K to tritium gas diluted with hydrogen. Then tritium concentration in the exposed specimens was measured as a function of depth using a chemical etching method. All the tritium concentration profiles showed a sharp drop in the range of 10 μm from the top surface up to the bulk. The amount of tritium absorbed into the polished specimens was three times larger than that into the as-received specimen. However, the polishing effects disappeared by exposing to the air for a long time.

  20. 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%.

  1. 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.

  2. Weld bead center line shift during laser welding of austenitic stainless steels with different sulfur content

    International Nuclear Information System (INIS)

    The magnitude of the shift in position of the maximum depth of penetration, the center line shift (CLS), for a laser weld produced between two heats of austenitic stainless steels with large differences in S content was smaller relative to gas tungsten arc (GTA) welds made with both higher and lower heat inputs. The results of this study suggest that both surface tension driven fluid (Marangoni) flow effects and arc shift effects may contribute to the CLS in GTA welding

  3. Diamond deposition on siliconized stainless steel

    International Nuclear Information System (INIS)

    Silicon diffusion layers in AISI 304 and AISI 316 type stainless steels were investigated as an alternative to surface barrier coatings for diamond film growth. Uniform 2 μm thick silicon rich interlayers were obtained by coating the surface of the steels with silicon and performing diffusion treatments at 800 deg. C. Adherent diamond films with low sp2 carbon content were deposited on the diffused silicon layers by a modified hot filament assisted chemical vapor deposition (HFCVD) method. Characterization of as-siliconized layers and diamond coatings was performed by energy dispersive X-ray analysis, scanning electron microscopy, X-ray diffraction and Raman spectroscopy.

  4. Fatigue fracture modes of a stainless steel

    International Nuclear Information System (INIS)

    The influence of strain hardening and martensite phase transformation on the fatigue fracture regions (pulsative tension) of a Stainless Steel type AISI 316 was investigated. This lead to the conclusion that the greater austenite strain hardening level only favours the occurrence of a brittle fracture. Also, in as much as the static induced martensite is concerned, a direct influence on the failure process was not observed, whereas, apparently, the one transformed under cyclic loading has no contribution to the rupture mechanisms. (author)

  5. Pitting corrosion resistant austenite stainless steel

    Science.gov (United States)

    van Rooyen, D.; Bandy, R.

    A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

  6. 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...... temperature (CPT) test as corrosion test. The following welding parameters are varied: Welding speed, lsser power, focus point position and laser operation mode (CW or pulsed)....

  7. Complex Protection of Vertical Stainless Steel Tanks

    OpenAIRE

    Fakhrislamov Radik Zakievich

    2014-01-01

    The authors consider the problem of fail-safe oil and oil products storage in stainless steel tanks and present the patented tank inner side protection technology. The latter provides process, ecological and fire safety and reducing soil evaporation of oil products, which is a specific problem. The above-mentioned technology includes corrosion protection and heat insulation protection providing increase of cover durability and RVS service life in general. The offered technological protection ...

  8. Cyclic deformation of duplex stainless steels

    OpenAIRE

    Mateo García, Antonio Manuel; Gironés, Ana

    2011-01-01

    Duplex stainless steels configure a family of metallic alloys that combined elevated mechanical properties with improved corrosion resistance when compared to standard austenitic grades. This excellent combination of properties leads to their use under many different applications, particularly in the fields of chemical, petrochemical, pulp and paper industries. Moreover, these applications usually involve cyclic loading, and consequently the study of fatigue properties has a great significanc...

  9. Thermal ageing of duplex stainless steels

    International Nuclear Information System (INIS)

    The evolution of the mechanical properties of Mobearing anf Mo-free cast duplex stainless steels, induced by long term ageing in the range 300-400 deg C, has been studied in relation with the evolution of their microstructure. The unmixing of the ferritic Fe-Cr-Ni, solid solution by three-dimensional (sponge-like) spinodal decomposition and the precipitation of intermetallic G-phase particles are the main characteristics of this microstructural evolution

  10. SRS stainless steel beneficial reuse program

    Energy Technology Data Exchange (ETDEWEB)

    Boettinger, W.L.

    1997-02-01

    The US Department of Energy`s (DOE) Savannah River Site (SRS) has thousands of tons of stainless steel radioactive scrap metal (RSNI). Much of the metal is volumetrically contaminated. There is no {open_quotes}de minimis{close_quotes} free release level for volumetric material, and therefore no way to recycle the metal into the normal commercial market. If declared waste, the metal would qualify as low level radioactive waste (LLW) and ultimately be dispositioned through shallow land buried at a cost of millions of dollars. The metal however could be recycled in a {open_quotes}controlled release{close_quote} manner, in the form of containers to hold other types of radioactive waste. This form of recycle is generally referred to as {open_quotes}Beneficial Reuse{close_quotes}. Beneficial reuse reduces the amount of disposal space needed and reduces the need for virgin containers which would themselves become contaminated. Stainless steel is particularly suited for long term storage because of its resistance to corrosion. To assess the practicality of stainless steel RSM recycle the SRS Benficial Reuse Program began a demonstration in 1994, funded by the DOE Office of Science and Technology. This paper discusses the experiences gained in this program.

  11. SCC of stainless steel under evaporative conditions

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, H.; Arnvig, P.E.; Wasielewska, W.; Wegrelius, L.; Wolfe, C. [Avesta Sheffield AB, Avesta (Sweden)

    1998-12-31

    Three different test methods have been used to assess the susceptibility of different stainless steel grades to SCC under evaporative and immersed conditions. The methods employed were the drop evaporation test, the wick test and a high temperature, high pressure test simulating a feedwater heater tubing application in power plants. The alloys investigated were commercially produced austenitic and duplex stainless steels varying in chemical composition, plus one copper-nickel alloy. The resistance of austenitic stainless steels towards SCC increased by increasing the content of Ni, Mo and Cr, thus the super austenitic 654SMO{reg_sign} (uns32654) did not show any cracking in any of the three tests. The super austenitic 254SMO{reg_sign} (UNS31254) revealed only slight SCC in the simulated feed water heater tubing application while the equivalent N08367 revealed severe pitting and cracking. The drop evaporation test exhibited the most severe test conditions characterized by thermally induced fatigue effects, sensibility to onset of corrosion and severe acidic conditions generated under deposits on the test specimen. Some factors in stress corrosion cracking tests such as thermal fatigue, diffusion, heat transfer and stress condition, are discussed with regard to their influence on the test results.

  12. Cavitation erosion resistance of diamond-like carbon coating on stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Feng; Jiang, Shuyun, E-mail: jiangshy@seu.edu.cn

    2014-02-15

    Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (−200 V/80 A, labeled DLC-1, and −100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

  13. Cavitation erosion resistance of diamond-like carbon coating on stainless steel

    Science.gov (United States)

    Cheng, Feng; Jiang, Shuyun

    2014-02-01

    Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (-200 V/80 A, labeled DLC-1, and -100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

  14. Aging degradation of cast stainless steel

    International Nuclear Information System (INIS)

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. Microstructures of cast materials subjected to long-term aging either in reactor service or in the laboratory have been characterized by TEM, SANS, and APFIM techniques. Two precipitate phases, i.e., the Cr-rich α' phase and the Ni- and Si-rich G phase, have been identified in the ferrite matrix of the aged steels. The results indicate that the low-temperature embrittlement is primarily caused by α' precipitates which form by spinodal decomposition. The relative contribution of the G phase to loss of toughness is now known. Microstructural data also indicate that weakening of the ferrite/austenite phase boundary by carbide precipitates has a significant effect on the onset and extent of embrittlement of the high-carbon CF-8 and CF-8M grades of stainless steels, particularly after aging at 400 or 4500C. Data from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 350, 400, and 4500C are presented and correlated with the microstructural results. Thermal aging of the steels results in an increase in tensile strength and a decrease in impact energy, J/sub IC/, and tearing modulus. The fracture toughness results show good agreement with the Charpy-impact data. The effects of compositional and metallurgical variables on loss of toughness are discussed

  15. Corrosion fatigue of a superduplex stainless steel weldment

    OpenAIRE

    Comer, Anthony John

    2004-01-01

    Superduplex stainless steels have superior mechanical and corrosion properties compared to austenitic stainless steels such as the grade 300 series. This is a result of a microstructure consisting of roughly equal percentages of austenite (y) and ferrite (a) and negligible inclusion content. As a result, super duplex stainless steels are increasingly being used in the offshore oil and gas industries. It is also envisaged that they will find application in the emergent renewable energy sec...

  16. Sinter-hardening process applicable to stainless steels

    OpenAIRE

    M. Rosso; Z. Brytan; L.A. Dobrzański

    2007-01-01

    Purpose: of this paper was to describe sintered duplex stainless steels manufactured in sinter-hardening process and its usability in field of stainless steels.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, ferritic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies apart from the preparation of mixes, Schaeffler’s diagram was taken into consideration. Pr...

  17. Development of oxide dispersion strengthened 2205 duplex stainless steel composite

    OpenAIRE

    Oladayo OLANIRAN; Peter Apata OLUBAMBI; Benjamin Omotayo ADEWUYI; Joseph Ajibade OMOTOYINBO; Ayodeji Ebenezar AFOLABI; Davies FOLORUNSO; Adekunle ADEGBOLA; Emanuel IGBAFEN

    2015-01-01

    Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction) dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr) and Nickel (Ni) were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail...

  18. Buckling response of ferritic stainless steel columns at elevated temperatures

    OpenAIRE

    Afshan, S; Gardner, L; Baddoo, NR

    2013-01-01

    This paper presents a numerical study on the buckling behaviour of ferritic stainless steel columns in fire. Finite element models were developed and validated against existing test results to predict the elevated temperature non-linear response of ferritic stainless steel columns. A total of nine austenitic and three ferritic stainless steel column tests were replicated using the finite element analysis package ABAQUS. Parametric studies were performed to investigate the effects of variation...

  19. 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.

  20. Electrochemical aspects of stainless steel behaviour in biocorrosive environment

    International Nuclear Information System (INIS)

    Electrochemical measurements have been used to evaluate and follow, to understand and control microbial induced corrosion of stainless steels. Results include seawater loop tests and laboratory-based microbiological experiments. With natural flowing seawater, impedance spectroscopy measurements have been used to evaluate and follow biofilms on stainless steel tube-electrodes. With batch cultures of single bacterial strain (Sulphate Reducing Bacteria), open-circuit potential measurements and polarization curves performed on 316 L and 430 Ti stainless steels, have shown that the corrosion behaviour of these stainless steels is mainly dependent on the sulphide content of the culture media

  1. Complex Protection of Vertical Stainless Steel Tanks

    Directory of Open Access Journals (Sweden)

    Fakhrislamov Radik Zakievich

    2014-03-01

    Full Text Available The authors consider the problem of fail-safe oil and oil products storage in stainless steel tanks and present the patented tank inner side protection technology. The latter provides process, ecological and fire safety and reducing soil evaporation of oil products, which is a specific problem. The above-mentioned technology includes corrosion protection and heat insulation protection providing increase of cover durability and RVS service life in general. The offered technological protection scheme is a collaboration of the author, Steel Paint GmbH firm and JSC “Koksokhimmontazhproyekt”. PU foam unicomponent materials of Steel Paint GmbH firm provide the protection of tank inner side and cover.

  2. Bacterial inhibition of silver-containing stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, W.C. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Mechanical Engineering; Chang, S.M.; Lin, J.D.; Tseng, I.S.; Wu, J.K. [National Taiwan Ocean Univ., Taiwan (China). Inst. of Materials Engineering

    2010-07-01

    In this study, silver (Ag) was added to AlSl 316 austenitic 2205 duplex and 430 ferritic stainless steels as a means of inhibiting bacterial contamination. Three Ag-containing stainless steels were prepared using vacuum melting techniques. The influence of the Ag addition on corrosion resistance, bacterial inhibition, and mechanical properties was investigated. A study of the Ag-containing stainless steel microstructures demonstrated that Ag precipitates as small particles on the steel matrix surface. The precipitates act as anodes in the local action cell in the presence of bacteria. Ag dissolution mechanisms from the Ag precipitates on the Ag-containing stainless steels in the presence of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were also discussed. Results of the study suggested that Ag-containing stainless steels may be used in areas where hygiene is a significant concern.

  3. Ion nitriding in 316=L stainless steel

    International Nuclear Information System (INIS)

    Ion nitriding is a glow discharge process that is used to induce surface modification in metals. It has been applied to 316-L austenitic stainless steel looking for similar benefits already obtained in other steels. An austenitic stainless steel was selected because is not hardenable by heat treatment and is not easy to nitride by gas nitriding. The samples were plastically deformed to 10, 20, 40, 50 AND 70% of their original thickness in order to obtain bulk hardening and to observe nitrogen penetration dependence on it. The results were: an increase of one to two rockwell hardness number (except in 70% deformed sample because of its thickness); an increase of even several hundreds per cent in microhardness knoop number in nitrided surface. The later surely modifies waste resistance which would be worth to quantify in further studies. Microhardness measured in an internal transversal face to nitrided surface had a gradual diminish in its value with depth. Auger microanalysis showed a higher relative concentration rate CN/CFe near the surface giving evidence of nitrogen presence till 250 microns deep. The color metallography etchant used, produced faster corrosion in nitrited regions. Therefore, corrosion studies have to be done before using ion nitrited 316-L under these chemicals. (Author)

  4. Spectrochemical determination of eight trace elements in stainless steel

    International Nuclear Information System (INIS)

    A method is described for the spectrochemical determination of Al, Pb, Sn, V, Nb, Cu, Co and Ti at trace levels in stainless steel. One hundred milligrammes of the stainless steel sample (in the form of turnings, filings, etc. ) are disolved in aqua regia. The solution is evaporated to dryness and then ignited over Bunsen flame to get a dark brown powder. The powder thus obtained is ground thoroughly with Specpure conducting graphite powder in the ratio 1:1 by weight and then with 2% NaF. Fifteen miligrammes of this mixture is taken in the cavity of a graphite electrode and excited in d.c. arc at 10 amps. The spectra of the sample and synthetic standards are recorded on a JACO 3.4 meter plane grating spectrograph, using a 1200 grooves/mm grating in the first order. The elements, Al, Pb, Sn, and V are estimated in the range 250-2500 ppm, by choosing suitable lines for internsity measurement. Iron is used as the internal standard element. (auth.)

  5. Spectrochemical determination of trace elements in stainless steel

    International Nuclear Information System (INIS)

    A method for the spectrochemical determination of Al, Pb, Sn, V, Nb, Cu and Ti at trace levels in stainless steel is reported. One hundred milligrammes of the stainless steel sample (in the form of turnings, filings, etc). were dissolved in aqua regia. The solution is evaporated to dryness and then ignited over Bunsen flame to get a dark brown powder. The powder thus obtained was ground thoroughly with specpure conducting graphite powder in the ratio 1:1 by weight and with 2% NaF. Fifteen milligrammes of this mixture were taken in the cavity of a graphite electrode and dc arc at 10 As. The spectra of the sample and synthetic standards were recorded on a JACO 3.4 on plane grating spectrograph, using 1200 grooves/mm grating in the first order. The elements, Al, Pb, Sn and V are estimated in the concentration range 50-500 ppm and Nb, Cu, Co and Ti in the range 250-2500 ppm, by choosing suitable lines for intensity measurement. Iron was used as the internal standards element. (auth.)

  6. Fatigue properties of duplex stainless steel

    OpenAIRE

    Turrel, Benjamin; Luna Garcia, Jordi; Andraschko, Stephan

    2009-01-01

    PFC presentat a Oslo University College The aim of the project is to study fatigue properties of duplex stainless steel used for a bridge. The samples had to be tested and the results have to be compared with the theory, studied before. Six specimens have been broken by tensile fatigue testing machine in order to get more knowledge about the lifetime and the behavior under dynamic stress and not only for welded parts. Out of this new knowledge a new fatigue curve for this ma...

  7. Effects of Mo content on microstructure and corrosion resistance of arc ion plated Ti-Mo-N films on 316L stainless steel as bipolar plates for polymer exchange membrane fuel cells

    Science.gov (United States)

    Zhang, Min; Kim, Kwang Ho; Shao, Zhigang; Wang, Feifei; Zhao, Shuang; Suo, Ni

    2014-05-01

    Bipolar plates are one of the most important components in PEMFC stack and have multiple functions, such as separators and current collectors, distributing reactions uniformly, and etc. Stainless steel is ideal candidate for bipolar plates owing to good thermal and electrical conductivity, good mechanical properties etc. However, stainless steel plate still cannot resist the corrosion of working condition. In this work, ternary Ti-Mo-N film was fabricated on 316L stainless steel (SS316L) as a surface modification layer to enhance the corrosion resistance. Effects of Mo content on the microstructure and corrosion resistance of Ti-Mo-N films are systematically investigated by altering sputtering current of the Mo target. XRD results reveal that the preferred orientation changes from [111] to [220] direction as Mo content in the film increases. The synthesized Ti-Mo-N films form a substitutional solid solution of (Ti, Mo)N where larger Mo atoms replace Ti in TiN crystal lattice. The TiN-coated SS316L sample shows the best corrosion resistance. While Mo content in the Ti-Mo-N films increases, the corrosion resistance gradually degrades. Compared with the uncoated samples, all the Ti-Mo-N film coated samples show enhanced corrosion resistance in simulated PEMFC working condition.

  8. Flow lines and microscopic elemental inhomogeneities in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Mosley, Jr, W C

    1982-01-01

    Flow lines in mechanically formed austenitic stainless steels are known to influence fracture behavior. Enhancement of flow lines by chemical etching is evidence of elemental inhomogeneity. This paper presents the results of electron microprobe analyses to determine the nature of flow lines in three austenitic stainless steels: 21Cr-6Ni-9Mn, 304L, and 19Ni-18Cr.

  9. 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...

  10. Evaluation of Microstructure and Mechanical Properties in Dissimilar Austenitic/Super Duplex Stainless Steel Joint

    Science.gov (United States)

    Rahmani, Mehdi; Eghlimi, Abbas; Shamanian, Morteza

    2014-10-01

    To study the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super duplex (ER2594) and an austenitic (ER309LMo) stainless steel filler metal. While the austenitic weld metal had vermicular delta ferrite within austenitic matrix, super duplex stainless steel was mainly comprised of allotriomorphic grain boundary and Widmanstätten side plate austenite morphologies in the ferrite matrix. Also the heat-affected zone of austenitic base metal comprised of large austenite grains with little amounts of ferrite, whereas a coarse-grained ferritic region was observed in the heat-affected zone of super duplex base metal. Although both welded joints showed acceptable mechanical properties, the hardness and impact strength of the weld metal produced using super duplex filler metal were found to be better than that obtained by austenitic filler metal.

  11. 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.

  12. 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.

  13. Characterization of silane layers on modified stainless steel surfaces and related stainless steel-plastic hybrids

    International Nuclear Information System (INIS)

    The aim of this work was to characterize silane layers on the modified stainless steel surfaces and relate it to the adhesion in the injection-molded thermoplastic urethane-stainless steel hybrids. The silane layers were characterized with scanning electron microscope and transmission electron microscope, allowing the direct quantization of silane layer thickness and its variation. The surface topographies were characterized with atomic force microscope and chemical analyses were performed with X-ray photoelectron spectroscopy. The mechanical strength of the respective stainless steel-thermoplastic urethane hybrids was determined by peel test. Polishing and oxidation treatment of the steel surface improved the silane layer uniformity compared to the industrially pickled surface and increased the adhesion strength of the hybrids, resulting mainly cohesive failure in TPU. XPS analysis indicated that the improved silane bonding to the modified steel surface was due to clean Fe2O3-type surface oxide and stronger interaction with TPU was due to more amino species on the silane layer surface compared to the cleaned, industrially pickled surface. Silane layer thickness affected failure type of the hybrids, with a thick silane layer the hybrids failed mainly in the silane layer and with a thinner layer cohesively in plastic.

  14. Operational experience with stainless steel condenser tubes

    International Nuclear Information System (INIS)

    Longitudinal seam welded tubes of stainless austenitic 18/8 CrNi and 18/8/2 CrNiMo steels have proved their worth when used in steam condensers with fresh water recooling. However, in water containing a high level of salt, in particular brackish water and seawater, experience to date has not been satisfactory in the case of these materials. High-alloy austenitic, ferritic and austenitic-ferritic steels developed during the last 10 years, on the other hand, have high pitting potentials and, both in the laboratory and in practice, have proved their suitability as heat-exchanger materials for steam condensers. These materials are easily worked to form welded tubes with a longitudinal seam and are therefore a relatively inexpensive design which ensures both plant safety and availability

  15. Thermodynamic calculation on the smelting slag of direct recycling of electric arc furnace stainless steelmaking dust

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Thermodynamic calculation on the smelting slag of direct recycling of electric arc furnace stainless steelmaking dust was presented. An induction furnace was used to simulate electric arc furnace smelting to recover the metals from the dust. The elements of iron, chromium and nickel in the ingot and the components of metal oxides in the slag were analyzed. The thermodynamic model for FeO-Cr2 O3-MgO-SiO2 slag was set up and the active concentrations of substances in the slag at 1 550 ℃C were determined by thermodynamic calculation according to the experimental data. The results show that the apparent equilibrium constant and quantitative distribution of chromium between slag and steel are unstable and affected by the mass ratios of pellets to start iron and metal reducing agent to the pellets. In order to get satisfactory chromium recovery from the direct recycling of electric arc furnace stainless steelmaking dust, it is important to ensure the mass ratio of pellets to the steel below 0.20 and the mass ratio of metal reducing agent to pellets over 0.18 in practical smelting runs.

  16. Weld oxide formation on lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Westin, E.M. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden)], E-mail: elin.westin@outokumpu.com; Olsson, C.-O.A. [Outokumpu Stainless, Avesta Research Centre, P.O. Box 74, SE-774 22 Avesta (Sweden); Hertzman, S. [Outokumpu Stainless Research Foundation, Brinellvaegen 23, SE-100 44 Stockholm (Sweden)

    2008-09-15

    Weld oxides have a strong influence on corrosion resistance, but have hitherto only been studied to a limited extent for duplex stainless steels. X-ray photoelectron spectroscopy (XPS) has here been used to study heat tint formed on gas tungsten arc (GTA) welds on the commercial duplex grades LDX 2101 (EN 1.4162/UNS S32101) and 2304 (EN 1.4362/UNS S32304) welded with and without nitrogen additions to the shielding gas. The process of heat tint formation is discussed in terms of transport phenomena to explain the effect of atmosphere, temperature and composition. The oxides formed were found to be enriched in manganese and corrosion testing shows that nitrogen has a strong influence on the weld oxide. A mechanism is proposed including evaporation from the weld pool and subsequent redeposition.

  17. Development of a lean duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Liljas, M.; Johansson, P.; Liu Hui-Ping; Olsson, C.O.A. [Avesta Research Centre, Avesta (Sweden). Outokumpu Stainless

    2008-06-15

    The classic series of duplex stainless steels shows very high corrosion resistance and can be used for very demanding applications. A new lean duplex steel, LDX 2101 {sup registered} (EN 1.4162, UNS S32101), has been developed with corrosion resistance on a par with standard austenitic grades. Application areas include: structural components, chemical industry, tanks and containers. The steel was designed to have equal amounts of ferrite and austenite in annealed condition and with an austenite that is stable against strain-induced martensite. Thanks to its high nitrogen content, the steel has a fast austenite reformation when subjected to thermal cycling, e.g. welding. Unlike conventional duplex grades, the formation of intermetallic phase is very sluggish, although precipitation of nitrides and carbides has a certain impact on material properties after exposure in the temperature range 600 to 800 C. The precipitation behaviour after different isothermal treatments is described and its influence on different product properties is shown. A good agreement was found between impact toughness and corrosion resistance for a wide range of thermal treatments. (orig.)

  18. Citric Acid Passivation of Stainless Steel

    Science.gov (United States)

    Yasensky, David; Reali, John; Larson, Chris; Carl, Chad

    2009-01-01

    Passivation is a process for cleaning and providing corrosion protection for stainless steel. Currently, on Kennedy Space Center (KSC), only parts passivated with nitric acid are acceptable for use. KSC disposes of approximately 125gal of concentrated nitric acid per year, and receives many parts from vendors who must also dispose of used nitric acid. Unfortunately, nitric acid presents health and environmental hazards. As a result, several recent industry studies have examined citric acid as an alternative. Implementing a citric acid-based passivation procedure would improve the health and environmental safety aspects of passivation process. However although there is a lack of published studies that conclusively prove citric acid is a technically sound passivation agent. In 2007, NASA's KSC Materials Advisory Working Group requested the evaluation of citric acid in place of nitric acid for passivation of parts at KSC. United Space Alliance Materials & Processes engineers have developed a three-phase test plan to evaluate citric acid as an alternative to nitric acid on three stainless steels commonly used at KSC: UNS S30400, S41000, and S17400. Phases 1 and 2 will produce an optimized citric acid treatment based on results from atmospheric exposure at NASA's Beach Corrosion Facility. Phase 3 will compare the optimized solution(s) with nitric acid treatments. If the results indicate that citric acid passivates as well or better than nitric acid, NASA intends to approve this method for parts used at the Kennedy Space Center.

  19. Carburization of stainless steel furnace tubes

    International Nuclear Information System (INIS)

    Stainless steel containing molybdenum are usually recommended to resist naphtenic acid corrosion in vacuum heaters. In 1993 the original 5Cr-1/2Mo roof tubes of the furnace in a vacuum unit were replaced by stainless steel 316 Ti to minimize tube replacement and increase heater reliability. Unexpectedly, some of the new tubes failed after only three years of service and just one year after undergoing the last inspection. The damage occurred in the form of deep holes and perforations, starting from the outside tube surface on the fireside. Coke build-up occurred due to severe operating conditions, overheating the tubes on the fireside, above 675 Centigrade. Metallographic and Scanning Electron Microscopy (Sem) examination revealed internal and external carburization of the material due to the presence of coke and combustion ashes, respectively. The increase in the skin metal temperature facilitated the diffusion of carbon from these carbon-rich deposits into the low carbon content material (0.023%). Depletion of chromium at the grain boundaries due to the massive formation of chromium carbides, resulted in a severe intergranular corrosion attack by molten salts rich in vanadium and sulfur produced by asphalt burning. Normal operating practice demands the use of steam for the heater tubes to control coke build-up. This practice had been first reduced and then eliminated, during the past two years prior to the failure, because of economic incentives. This paper describes the root cause analysis conducted to account for these premature tube failures. (Author)

  20. Fracture toughness of irradiated stainless steel alloys

    International Nuclear Information System (INIS)

    The postirradiation fracture toughness responses of Types 316 and 304 stainless steel (SS) wrought products, cast CF8 SS and Type 308 SS weld deposit were characterized at 4270C using J/sub R/-curve techniques. Fast-neutron irradiation of these alloys caused an order of magnitude reduction in J/sub c/ and two orders of magnitude reduction in tearing modulus at neutron exposures above 10 dpa, where radiation-induced losses in toughness appeared to saturate. Saturation J/sub c/ values for the wrought materials ranged from 28 to 31 kJ/m2; the weld exhibited a saturation level of 11 kJ/m2. Maximum allowable flaw sizes for highly irradiated stainless steel components stressed to 90% of the unirradiated yield strength are on the order of 3 cm for the wrought material and 1 cm for the weld. Electron fractographic examination revealed that irradiation displacement damage brought about a transition from ductile microvoid coalescence to channel fracture, associated with local separation along planar deformation bands. The lower saturation toughness value for the weld relative to that for the wrought products was attributed to local failure of ferrite particles ahead of the advancing crack which prematurely initiated channel fracture

  1. Embrittlement of austenitic stainless steel welds

    Energy Technology Data Exchange (ETDEWEB)

    David, S.A.; Vitek, J.M. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-31

    The microstructure of type-308 austenitic stainless steel weld metal containing {gamma} and {delta} and ferrite is shown. Typical composition of the weld metal is Cr-20.2, Ni-9.4, Mn-1.7, Si-0.5, C-0.05, N-0.06 and balance Fe (in wt %). Exposure of austenitic stainless steel welds to elevated temperatures can lead to extensive changes in the microstructural features of the weld metal. On exposure to elevated temperatures over a long period of time, a continuous network of M{sub 23}C{sub 6} carbide forms at the austenite/ferrite interface. Upon aging at temperatures between 550--850 C, ferrite in the weld has been found to be unstable and transforms to sigma phase. These changes have been found to influence mechanical behavior of the weld metal, in particular the creep-rupture properties. For aging temperatures below 550 C the ferrite decomposes spinodally into {alpha} and {alpha}{prime} phases. In addition, precipitation of G-phase occurs within the decomposed ferrite. These transformations at temperatures below 550 C lead to embrittlement of the weld metal as revealed by the Charpy impact properties.

  2. Assessment of thermal embrittlement of cast stainless steels

    International Nuclear Information System (INIS)

    A procedure and correlations are presented for assessing thermal embrittlement and predicting Charpy-impact energy and fracture toughness J-R curve of cast stainless steel components under Light Water Reactor operating conditions from known material information. The ''saturation'' impact strength and fracture toughness of a specific cast stainless steel, i.e., the minimum value that would be achieved for the material after long-term service, is estimated from the chemical composition of the steel. Fracture properties as a function of time and temperature of reactor service are estimated from the kinetics of embrittlement, which are also determined from chemical composition. A common ''predicted lower-bound'' J-R curve for cast stainless steels of unknown chemical composition is also defined for a given grade of steel, ferrite content, and temperature. Examples of estimating fracture toughness of cast stainless steel components during reactor service are presented

  3. EXPERIMENTAL RESEARCH OF THE DUPLEX STAINLESS STEEL WELDS IN SHIPBUILDING

    OpenAIRE

    Juraga, Ivan; Stojanović, Ivan; Ljubenkov, Boris

    2014-01-01

    Duplex stainless steel is used in shipbuilding increasingly because of its good mechanical properties and marked corrosion resistance. This steel has a two phase structure (austenite-ferrite) which is sensitive on heat input during welding because of the possible ferritisation appearance, that is, increase in ferrite content in the area of heat effected zone (HAZ) which can lead to loss of mechanical and corrosion properties. Work with duplex stainless steel requires special attention in ever...

  4. Nickel-free Stainless Steel for Medical Applications

    Institute of Scientific and Technical Information of China (English)

    Yibin REN; Ke YANG; Bingchun ZHANG; Yaqing WANG; Yong LIANG

    2004-01-01

    BIOSS4 steel is essentially a nickel-free austenitic stainless steel developed by the Institute of Metal Research, Chinese Academy of Sciences, in response to nickel allergy problems associated with nickel-containing stainless steels that are widely used in medical applications. The high nitrogen content of this steel effectively maintains the austenitic stability and also contributes to the high levels of corrosion resistance and strength. BIOSS4 steel possesses a good combination of high strength and toughness, better corrosion resistance, and better blood compatibility, in comparison with the medical 316L stainless steel. Potential applications of BIOSS4 steel can include medical implantation material and orthodontic or orthopedic devices, as well as jewelries and other decorations.

  5. Dilution and Ferrite Number Prediction in Pulsed Current Cladding of Super-Duplex Stainless Steel Using RSM

    Science.gov (United States)

    Eghlimi, Abbas; Shamanian, Morteza; Raeissi, Keyvan

    2013-12-01

    Super-duplex stainless steels have an excellent combination of mechanical properties and corrosion resistance at relatively low temperatures and can be used as a coating to improve the corrosion and wear resistance of low carbon and low alloy steels. Such coatings can be produced using weld cladding. In this study, pulsed current gas tungsten arc cladding process was utilized to deposit super-duplex stainless steel on high strength low alloy steel substrates. In such claddings, it is essential to understand how the dilution affects the composition and ferrite number of super-duplex stainless steel layer in order to be able to estimate its corrosion resistance and mechanical properties. In the current study, the effect of pulsed current gas tungsten arc cladding process parameters on the dilution and ferrite number of super-duplex stainless steel clad layer was investigated by applying response surface methodology. The validity of the proposed models was investigated by using quadratic regression models and analysis of variance. The results showed an inverse relationship between dilution and ferrite number. They also showed that increasing the heat input decreases the ferrite number. The proposed mathematical models are useful for predicting and controlling the ferrite number within an acceptable range for super-duplex stainless steel cladding.

  6. In vivo behavior of a high performance duplex stainless steel.

    Science.gov (United States)

    Cigada, A; De Santis, G; Gatti, A M; Roos, A; Zaffe, D

    1993-01-01

    An in vivo investigation of a new high molybdenum and nitrogen duplex stainless steel (25Cr--7Ni--4Mo--0.3N) has been performed. Cylindrical pins and specially developed devices, to test in static conditions the in vivo localized corrosion resistance, made of this new duplex steel and of a common austenitic stainless steel were implanted in rabbit's femurs for 6 and 12 months. After sacrifice, SEM observations and EDS microanalyses to detect metallic ion release were carried out on the femur sections surrounding the pins. Morphologic observations with stereoscope and SEM were performed on the metallic surfaces of the special devices in order to detect the presence of localized corrosion. Both ion release and localized corrosion were observed for the specimens made of austenitic stainless steel, but not for those made of 25Cr--7Ni--4Mo--0.3N duplex stainless steel. PMID:10148344

  7. Microbial-Influenced Corrosion of Corten Steel Compared with Carbon Steel and Stainless Steel in Oily Wastewater by Pseudomonas aeruginosa

    Science.gov (United States)

    Mansouri, Hamidreza; Alavi, Seyed Abolhasan; Fotovat, Meysam

    2015-07-01

    The microbial corrosion behavior of three important steels (carbon steel, stainless steel, and Corten steel) was investigated in semi petroleum medium. This work was done in modified nutrient broth (2 g nutrient broth in 1 L oily wastewater) in the presence of Pseudomonas aeruginosa and mixed culture (as a biotic media) and an abiotic medium for 2 weeks. The behavior of corrosion was analyzed by spectrophotometric and electrochemical methods and at the end was confirmed by scanning electron microscopy. The results show that the degree of corrosion of Corten steel in mixed culture, unlike carbon steel and stainless steel, is less than P. aeruginosa inoculated medium because some bacteria affect Corten steel less than other steels. According to the experiments, carbon steel had less resistance than Corten steel and stainless steel. Furthermore, biofilm inhibits separated particles of those steels to spread to the medium; in other words, particles get trapped between biofilm and steel.

  8. Compressibility of 304 Stainless Steel Powder Metallurgy Materials Reinforced with 304 Short Stainless Steel Fibers

    Directory of Open Access Journals (Sweden)

    Bibo Yao

    2016-03-01

    Full Text Available Powder metallurgy (P/M technique is usually used for manufacturing porous metal materials. However, some P/M materials are limitedly used in engineering for their performance deficiency. A novel 304 stainless steel P/M material was produced by a solid-state sintering of 304 stainless steel powders and 304 short stainless steel fibers, which were alternately laid in layers according to mass ratio. In this paper, the compressive properties of the P/M materials were characterized by a series of uniaxial compression tests. The effects of fiber content, compaction pressure and high temperature nitriding on compressive properties were investigated. The results indicated that, without nitriding, the samples changed from cuboid to cydariform without damage in the process of compression. The compressive stress was enhanced with increasing fiber content ranging from 0 to 8 wt.%. For compaction pressure from 55 to 75 MPa, greater compaction pressure improved compressive stress. Moreover, high temperature nitriding was able to significantly improve the yield stress, but collapse failure eventually occurred.

  9. A mortality study among mild steel and stainless steel welders.

    Science.gov (United States)

    Moulin, J J; Wild, P; Haguenoer, J M; Faucon, D; De Gaudemaris, R; Mur, J M; Mereau, M; Gary, Y; Toamain, J P; Birembaut, Y

    1993-03-01

    A mortality study was carried out in conjunction with the European mortality study among welders coordinated by the International Agency for Research on Cancer (IARC). The study was aimed at assessing risks for lung cancer in relation to exposure to asbestos, welding fumes containing chromium and nickel, and tobacco smoke. The study included a cohort of 2721 welders and an internal comparison group of 6683 manual workers employed in 13 factories in France. The mortality of the two cohorts was studied from 1975 to 1988 by the historical prospective method. Job histories of welders were traced including welding processes used, metals welded, and proportion of worktime spent in welding. Data on smoking habits were collected from medical records. The observed number of deaths were compared with those expected (standardised mortality ratio (SMR)) based on national rates with adjustments for age, sex, and calendar time. The smoking habits of 87% of the whole study population were known. The distribution of welders and controls according to smoking was not statistically different. The overall mortality was slightly higher for welders (SMR = 1.02, 95% confidence interval (95% CI) 0.89-1.18) than for controls (SMR = 0.91, 95% CI 0.84-0.99). For lung cancer, the SMR was 1.24 (95% CI 0.75-1.94) for welders, whereas the corresponding value was lower for controls (SMR = 0.94, 95% CI 0.68-1.26). The SMR for lung cancer was 1.59 among non-shipyard mild steel welders (95% CI 0.73-3.02). This contrasted with the results for all stainless steel welders (SMR = 0.92, 95% CI 0.19-2.69), and for stainless steel welders predominantly exposed to chromium VI (SMR = 1.03, 95% CI 0.12-3.71). Moreover, SMRs for lung cancer for mild steel welders tended to increase with duration of exposure and time since first exposure, leading to significant excesses for duration > or = 20 years and latency > or = 20 years. Such a pattern was not found for stainless steel welders.

  10. A mathematical approach based on finite differences method for analyzing the temperature field in arc welding of stainless steel thin sheets; Desarrollo de un modelo matematico de diferencias finitas para el analisis del campo de temperaturas en la soldadura por arco de chapas finas de acero inoxidable

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Conesa, E.J.; Estrems, M.; Miguel, V.

    2010-07-01

    This work develops a finite difference method to evaluate the temperature field in the heat affected zone in butt welding applied to AISI 304 stainless steel thin sheet by GTAW process. A computer program has been developed and implemented by Visual Basic for Applications (VBA) in MS-Excel spreadsheet. The results that are obtained using the numerical application foresee the thermal behaviour of arc welding processes. An experimental methodology has been developed to validate the mathematical model that allows to measure the temperature in several points close to the weld bead. The methodology is applied to a stainless steel sheet with a thickness lower than 3 mm, although may be used for other steels and welding processes as MIG/MAG and SMAW. The data which has been obtained from the experimental procedure have been used to validate the results that have been calculated by the finite differences numerical method. The mathematical model adjustment has been carried out taking into account the experimental results. The differences found between the experimental and theoretical approaches are due to the convection and radiation heat losses, which have not been considered in the simulation model.With this simple model, the designer will be able to calculate the thermal cycles that take place in the process as well as to predict the temperature field in the proximity of the weld bead. (Author). 18 refs.

  11. Nitrogen bearing austenitic stainless steels for surgical implants

    Energy Technology Data Exchange (ETDEWEB)

    Tschiptschin, A.P.; Aidar, C.H.; Alonso-Falleiros, N. [Sao Paulo Univ. (Brazil). Escola Politecnica; Neto, F.B. [Instituto de Pesquisas Tecnologicas, Sao Paulo (Brazil)

    1999-07-01

    Nitrogen addition promotes substantial improvements on general and localized corrosion performance of stainless steels. In recent times high nitrogen (up to 0.6 wt%) and Mn bearing super austenitic stainless steel has been studied for medical applications due to its low Ni content, the so called body friendly alloys. 18%Cr, 0.4%N and 15%Mn stainless steels were cast either from electrolytic or commercial master alloys in induction furnace, forged, solubilized at 1423K for 3 hours and water quenched. Delta ferrite and carbide precipitate free structures were observed. (orig.)

  12. Structural Analysis of Cavitation for Different Stainless Steels

    Directory of Open Access Journals (Sweden)

    Mădălina-Elena Mânzână

    2011-09-01

    Full Text Available The cavitation phenomenon is currently approaching all areas of technology and modern industry, where are fluid in motion. In this paper cavitational erosion was conducted on different samples of stainless steels. The cavitation were performed in magnetostrictive vibrating apparatus at Cavitation Laboratory (Polytechnic University of Timisoara. The present paper intends to identify specific structural features in stainless steels. Several investigations were done: macrostructural analysis (Olympus SZX57, scaning electron microscope (Philips SEM and X-ray diffraction (D8 ADVANCE. After quantitative and qualitative investigations structural features were put in evidence on experimental stainless steels.

  13. Investigation of the Hot Plasticity of Duplex Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    LIN Gang; ZHANG Zhi-xia; SONG Hong-wei; TONG Jun; ZHOU Can-dong

    2008-01-01

    Hot plasticity of a nitrogen alloyed 25Cr-7Ni-4 Mo duplex stainless steel was investigated.The results indicate that thc main factors affecting the hot plasticity of duplex stainless steel are listed as follows:coalescent force of phase interface,microstructure,and the phase ratio and difference between the mechanicsl propertms of ferrite and austenite.The heat treatment and sulphur contents have a notable effect on the hot plasticity.The reasonable heat treatrnents and the irlcreased interfacial coalescent force will effectively enhance the hot plasticity of duplex stainless steel.

  14. Magnetic characterisation of duplex stainless steel

    Science.gov (United States)

    Mészáros, I.

    2006-02-01

    Heat treatment-induced microstructural processes were studied by different non-destructive magnetic and mechanical material testing methods in the present work. A commercial SAF 2507 type superduplex stainless steel was investigated. This alloy contains about 40% metastable ferrite which can decompose to a sigma phase and secondary austenite due to heat treatment. All the mechanical, corrosion resistance and magnetic properties are strongly influenced by this microstructural changes. This study had two aims: to understand better the kinetics of the ferrite decomposition process and to study the application possibilities of the applied magnetic measurements. This paper presents an application possibility of the nonlinear harmonics analysis measurement and demonstrates the possibility to find a quantitative correlation between measured harmonics and mechanical properties obtained from destructive tests.

  15. Electrochemical decontamination of Pu contaminated stainless steel

    International Nuclear Information System (INIS)

    Electrochemical decontamination has been demonstrated to be very effective in removing plutonium nitrate contamination (0.5 μg cm-2) on stainless steels. The amount of metal dissolved to achieve a DF of 102 to 103 was 2 to 7 μm depending on the electrolyte used. In unstirred electrolytes 1M HNO3, 1M HNO3/0.1M NaF, 5M HNO3 perform best. Under stirred electrolyte conditions, there is a general marginal fall in effectiveness except for 5M HNO3 where there is a slight improvement. The optimum performance is a compromise between maximizing the electrolyte throwing power and minimizing substrate surface roughening during decontamination. (author)

  16. MOCVD deposition of YSZ on stainless steels

    Science.gov (United States)

    Chevalier, S.; Kilo, M.; Borchardt, G.; Larpin, J. P.

    2003-01-01

    Yttria stabilized zirconia was deposited on stainless steel using the metal-organic chemical vapor deposition (MOCVD) technique, from β-diketonate precursors. The variation of the evaporation temperatures of yttrium and zirconium precursor allowed to control the level of Y within the film. Over the temperature range 125-150 °C, the Y content increased from 2.5 to 17.6 at.%. X-ray diffraction (XRD) analyses evidenced tetragonal phase of zirconia when the Y content was below 8 at.%, and cubic phase for higher concentration. Sputtered neutral mass spectrometry (SNMS) profiles confirmed that the control and stability of Y precursor temperature were of major importance to guarantee the homogeneity of the deposited films.

  17. A stainless steel bracket for orthodontic application.

    Science.gov (United States)

    Oh, Keun-Taek; Choo, Sung-Uk; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2005-06-01

    Aesthetics has become an essential element when choosing orthodontic fixed appliances. Most metallic brackets used in orthodontic therapy are made from stainless steel (SS) with the appropriate physical properties and good corrosion resistance, and are available as types 304, 316 and 17-4 PH SS. However, localized corrosion of these materials can frequently occur in the oral environment. This study was undertaken to evaluate the accuracy of sizing, microstructure, hardness, corrosion resistance, frictional resistance and cytotoxicity of commercially available Mini-diamond (S17400), Archist (S30403) and experimentally manufactured SR-50A (S32050) brackets. The size accuracy of Mini-diamond was the highest at all locations except for the external horizontal width of the tie wing (P SS brackets. PMID:15947222

  18. MICROSCOPIC CORROSION STUDIES OF DUPLEX STAINLESS STEELS

    Institute of Scientific and Technical Information of China (English)

    C.Leygraf; J.Pan; M.Femenia

    2004-01-01

    Electrochemical scanning tunneling microscopy and scanning electrochemical microscopy have been used for in situ monitoring of localized corrosion processes of different Duplex stainless steels (DSS) in acidic chloride solutions. The techniques allow imaging of local dissolution events with micrometer resolution, as opposed to conventional electrochemical techniques, which only give an overall view of the corrosion behavior. In addition, combined scanning Kelvin probe force microscopy and magnetic force microscopy were used for mapping the Volta potential variation over the surface of DSSs. A significant difference in Volta potential between the austenite and ferrite phases suggests galvanic interaction between the phases. A compositional gradient appears within 2 micrometers across the phase boundary, as seen with scanning Auger microscopy (SAM). In all, the studies suggest that higher alloyed DSS exhibit a more homogeneous dissolution behavior than lower alloyed DSS, due to higher and more similar corrosion resistance of the two phases, and enhanced resistance of the ferrite/austenite phase boundary regions.

  19. Thermal fatigue crack growth in stainless steel

    International Nuclear Information System (INIS)

    A judgment of residual service life of engineering parts exposed to thermal fatigue makes it possible to deal with economic and safety issues in power plants. The aim of this study is to analyze a fatigue crack initiation and propagation in A321 stainless steel bodies subjected to repeated thermal shocks. For this purpose, various methods of crack propagation monitoring were used. The first stage of experiments included mechanical cyclic loading of specimens with the central notch at fixed temperatures ranging from 20 °C to 410 °C. The crack growth rate was only minimally influenced by temperature in this case. Thermal loading of the same specimens with ΔT varying from 150 °C to 340 °C showed very rapid crack initiation in the notches and its asymmetric growth. Metallographic and fractographic analyses of failed specimens were carried out after 1000, 3000 and 6000 thermal cycles. The comparison of the fracture surface micromorphology confirmed the similarity in the mechanism of the thermal and mechanical fatigue crack growth. Stress analysis using the finite element method consisting of transient thermal and mechanical solutions was performed in order to simulate the experiments. Thermal fatigue crack growth assessment was carried out on the basis of the experiments and the computed thermally induced stress intensity factors. This model successfully confirms the discussed analogy of thermal and mechanical stress induced damage. Highlights: ► A fatigue crack initiation and propagation in A321 stainless steel was analyzed. ► Mechanical and thermal experiments were performed, simulated also by FEM. ► Similarity in the mechanism of thermal and mechanical fatigue crack growth found. ► Application of the Paris model for the thermal cycling confirmed.

  20. Behaviour and design of cold-formed lean duplex stainless steel members

    OpenAIRE

    Huang, Yun'er; 黃韵兒

    2013-01-01

    Cold-formed stainless steel sections have been increasingly used in architectural and structural applications. Yet the high price of stainless steel limits the application to construction projects. The lean duplex stainless steel (EN 1.4162) offers an opportunity for stainless steels to be used more widely due to its competitive in price, good mechanical properties and corrosion resistance. The lean duplex stainless steel is a relatively new material, and research on this material is limited....

  1. Effects of Cr2N Precipitation on the Antibacterial Properties of AISI 430 Stainless Steel

    OpenAIRE

    Je-Kang Du; Chih-Yeh Chao; Yu-Ting Jhong; Chung-Hao Wu; Ju-Hui Wu

    2016-01-01

    Based on their mechanical properties and good corrosion resistance, some commercial Ni-Cr stainless steels have been widely applied as biomaterials, including the austenitic 304 stainless steel, the austenitic 316 stainless steel, the duplex 2205 stainless steel, and the ferritic 430 stainless steel. In order to reduce the occurrence of infections resulting from biomaterial implants, instruments, and medical devices, Cu2+ and Ag2+ ions have been added onto biomaterials for increasing the anti...

  2. Stainless steel anodes for alkaline water electrolysis and methods of making

    Science.gov (United States)

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  3. Characterization of Process Conditions in Industrial Stainless Steelmaking Electric Arc Furnace Using Optical Emission Spectrum Measurements

    Science.gov (United States)

    Aula, Matti; Leppänen, Ahti; Roininen, Juha; Heikkinen, Eetu-Pekka; Vallo, Kimmo; Fabritius, Timo; Huttula, Marko

    2014-06-01

    Emission spectroscopy is a potential method for gaining information on electric arc furnace (EAF) process conditions. Previous studies published in literature on industrial EAF emission spectra have focused on a smaller scales and DC arc furnaces. In this study emission spectrum measurements were conducted for 140t AC stainless steelmaking EAF at Outokumpu Stainless Oy, Tornio Works, Finland. Four basic types of emission spectra were obtained during the EAF process cycle. The first one is obscured by scrap steel, the second is dominated by thermal radiation of the slag, the third is dominated by alkali peaks and sodium D-lines and the fourth is characterized by multiple atomic emission peaks. The atomic emission peaks were identified by comparing them to the NIST database for atomic emission lines and previous laboratory measurements on EAF slag emission spectra. The comparison shows that the optic emission of an arc is dominated by slag components. Plasma conditions were analyzed by deriving plasma temperature from optical emissions of Ca I lines. The analysis suggests that accurate information on plasma conditions can be gained from outer plasma having a plasma temperature below 7000 K (6727 °C).

  4. Bacterial adhesion on ion-implanted stainless steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Q. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom)]. E-mail: q.zhao@dundee.ac.uk; Liu, Y. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom); Wang, C. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom); Wang, S. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom); Peng, N. [Surrey Ion Beam Centre, University of Surrey, Surrey GU2 7XH (United Kingdom); Jeynes, C. [Surrey Ion Beam Centre, University of Surrey, Surrey GU2 7XH (United Kingdom)

    2007-08-31

    Stainless steel disks were implanted with N{sup +}, O{sup +} and SiF{sub 3} {sup +}, respectively at the Surrey Ion Beam Centre. The surface properties of the implanted surfaces were analyzed, including surface chemical composition, surface topography, surface roughness and surface free energy. Bacterial adhesion of Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus aureus, which frequently cause medical device-associated infections was evaluated under static condition and laminar flow condition. The effect of contact time, growth media and surface properties of the ion-implanted steels on bacterial adhesion was investigated. The experimental results showed that SiF{sub 3} {sup +}-implanted stainless steel performed much better than N{sup +}-implanted steel, O{sup +}-implanted steel and untreated stainless steel control on reducing bacterial attachment under identical experimental conditions.

  5. Bacterial adhesion on ion-implanted stainless steel surfaces

    International Nuclear Information System (INIS)

    Stainless steel disks were implanted with N+, O+ and SiF3+, respectively at the Surrey Ion Beam Centre. The surface properties of the implanted surfaces were analyzed, including surface chemical composition, surface topography, surface roughness and surface free energy. Bacterial adhesion of Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus aureus, which frequently cause medical device-associated infections was evaluated under static condition and laminar flow condition. The effect of contact time, growth media and surface properties of the ion-implanted steels on bacterial adhesion was investigated. The experimental results showed that SiF3+-implanted stainless steel performed much better than N+-implanted steel, O+-implanted steel and untreated stainless steel control on reducing bacterial attachment under identical experimental conditions

  6. Bacterial adhesion on ion-implanted stainless steel surfaces

    Science.gov (United States)

    Zhao, Q.; Liu, Y.; Wang, C.; Wang, S.; Peng, N.; Jeynes, C.

    2007-08-01

    Stainless steel disks were implanted with N +, O + and SiF 3+, respectively at the Surrey Ion Beam Centre. The surface properties of the implanted surfaces were analyzed, including surface chemical composition, surface topography, surface roughness and surface free energy. Bacterial adhesion of Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus aureus, which frequently cause medical device-associated infections was evaluated under static condition and laminar flow condition. The effect of contact time, growth media and surface properties of the ion-implanted steels on bacterial adhesion was investigated. The experimental results showed that SiF 3+-implanted stainless steel performed much better than N +-implanted steel, O +-implanted steel and untreated stainless steel control on reducing bacterial attachment under identical experimental conditions.

  7. Mechanical properties and corrosion resistance of dissimilar stainless steel welds

    Directory of Open Access Journals (Sweden)

    J. Łabanowski

    2007-01-01

    Full Text Available Purpose: The purpose of this paper is to determine the influence of welding on microstructure, mechanical properties, and stress corrosion cracking resistance of dissimilar stainless steels butt welded joints.Design/methodology/approach: Duplex 2205 and austenitic 316L steels were used. Butt joints of plates 15 mm in thickness were performed with the use of submerged arc welding (SAW method. The heat input was in the range of 1.15 – 3.2 kJ/mm. Various plates’ edge preparations were applied. Microstructure examinations were carried out. Mechanical properties were evaluated in tensile tests, bending tests and Charpy-V toughness tests. Susceptibility to stress corrosion cracking was determined with the use of slow strain rate tests (SSRT performed in inert (glycerin and aggressive (boiling 35% MgCl2 solution environments.Findings: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate mechanical properties as well as stress corrosion cracking resistance of welds.Practical implications: All tested joints showed acceptable mechanical properties. Metallographic examinations did not indicate the excessive ferrite contents in heat affected zones (HAZ of the welds. It was shown that area of the lowest resistance to stress corrosion cracking is heat affected zone at duplex steel side of dissimilar joins. That phenomenon is connected with undesirable structure of that zone consisted of greater amounts of coarse ferrite grains and acicular austenite precipitates. High heat inputs do not deteriorate

  8. Study and development of solid fluxes for gas tungsten arc welding applied to titanium and its alloys and stainless steels; Etude et developpement des flux solides en vue d'application en soudage ATIG applique au titane et ses alliages ainsi qu'aux aciers inoxydables

    Energy Technology Data Exchange (ETDEWEB)

    Perry, N

    2000-06-15

    Gas Tungsten Arc Welding uses an electric arc between the refractory tungsten electrode and the plates to be welded under an argon shielding gas. As a result, the joint quality is excellent, no pollution nor defects are to be feared, consequently this process is used in nuclear, aeronautic, chemical and food industries. Despite of this good qualities, GTAW is limited because of, on the one side, a poor penetrating weld pool and, on the other side, a week productivity rate. Indeed, up to 3 mm thick plates, machining and filler metal is needed. Multiple runs increase the defect's risks, the manufactory time and increase the deformations and the heat affected zone. The goal of this study is to break through this limits without any device investment. Active GTA welding (or ATIG) is a new technique with GTA device and an activating flux to be spread on the upper plate before welding. The arc, by plasma electrochemical equilibrium modifications, and the pool with the inner connective flows inversion, allow 7 mm thick joints in one run without edges machining or filler metal for both stainless steel and titanium alloys. This manuscript describes the development of these fluxes, highlights the several phenomena and presents the possibilities of this new process. This work, in collaboration with B.S.L. industries, leads to two flux formulations (stainless steel and titanium alloys) now in a commercial phase with CASTOLIN S.A. Moreover, B.S.L.industries produces a pressure device (nitrate column) with the ATIG process using more than 2800 ATIG welds. (author)

  9. Phase Transformations in Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Yoon-Jun Kim

    2004-12-19

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as {sigma} and {chi} can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase ({sigma} + {chi}) formation were analyzed using the Johnson-Mehl-Avrami (MA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities; a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, {sigma} was stabilized with increasing Cr addition and {chi} by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in

  10. Phase transformations in cast duplex stainless steels

    Science.gov (United States)

    Kim, Yoon-Jun

    Duplex stainless steels (DSS) constitute both ferrite and austenite as a matrix. Such a microstructure confers a high corrosion resistance with favorable mechanical properties. However, intermetallic phases such as sigma (sigma) and chi (chi) can also form during casting or high-temperature processing and can degrade the properties of the DSS. This research was initiated to develop time-temperature-transformation (TTT) and continuous-cooling-transformation (CCT) diagrams of two types of cast duplex stainless steels, CD3MN (Fe-22Cr-5Ni-Mo-N) and CD3MWCuN (Fe-25Cr-7Ni-Mo-W-Cu-N), in order to understand the time and temperature ranges for intermetallic phase formation. The alloys were heat treated isothermally or under controlled cooling conditions and then characterized using conventional metallographic methods that included tint etching, and also using electron microscopy (SEM, TEM) and wavelength dispersive spectroscopy (WDS). The kinetics of intermetallic-phase (sigma + chi) formation were analyzed using the Johnson-Mehl-Avrami (JMA) equation in the case of isothermal transformations and a modified form of this equation in the case of continuous cooling transformations. The rate of intermetallic-phase formation was found to be much faster in CD3MWCuN than CD3MN due mainly to differences in the major alloying contents such as Cr, Ni and Mo. To examine in more detail the effects of these elements of the phase stabilities, a series of eight steel castings was designed with the Cr, Ni and Mo contents systematically varied with respect to the nominal composition of CD3MN. The effects of varying the contents of alloying additions on the formation of intermetallic phases were also studied computationally using the commercial thermodynamic software package, Thermo-Calc. In general, a was stabilized with increasing Cr addition and chi by increasing Mo addition. However, a delicate balance among Ni and other minor elements such as N and Si also exists. Phase equilibria in

  11. Eddy sensors for small diameter stainless steel tubes.

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Jack L.; Morales, Alfredo Martin; Grant, J. Brian; Korellis, Henry James; LaFord, Marianne Elizabeth; Van Blarigan, Benjamin; Andersen, Lisa E.

    2011-08-01

    The goal of this project was to develop non-destructive, minimally disruptive eddy sensors to inspect small diameter stainless steel metal tubes. Modifications to Sandia's Emphasis/EIGER code allowed for the modeling of eddy current bobbin sensors near or around 1/8-inch outer diameter stainless steel tubing. Modeling results indicated that an eddy sensor based on a single axial coil could effectively detect changes in the inner diameter of a stainless steel tubing. Based on the modeling results, sensor coils capable of detecting small changes in the inner diameter of a stainless steel tube were designed, built and tested. The observed sensor response agreed with the results of the modeling and with eddy sensor theory. A separate limited distribution SAND report is being issued demonstrating the application of this sensor.

  12. 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...

  13. Development of oxide dispersion strengthened 2205 duplex stainless steel composite

    Directory of Open Access Journals (Sweden)

    Oladayo OLANIRAN

    2015-05-01

    Full Text Available Composites of duplex stainless steel were produced by oxide dispersion strengthening with comparatively improved mechanical properties by hot press sintering of partially stabilized Zirconia (PSZ, 3% yttria, mole fraction dispersion in 2205 duplex stainless steels. Ceramic oxide was added as reinforcement, while chromium (Cr and Nickel (Ni were incorporated to maintain the austenitic/ferritic phase balance of the duplex stainless steel. The powders and sintered were characterized in detail using scanning electron microscopy (SEM and X-ray diffraction (XRD. The microstructural evolution and phase formation during oxide dispersion strengthening of duplex stainless steel composites were investigated. The influence of composition variation of the reinforcements on the microstructural and corrosion behaviour in simulated mine water of the composites were investigated. In this manuscript, it was established that composition has great influence on the structure/properties relationship of the composites developed.

  14. 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.

  15. Corrosion Resistance of TiN and CrN Coatings with Arc Ion Plating on 201 Stainless Steel Surface%201不锈钢表面弧光离子镀TiN和CrN薄膜的耐蚀性

    Institute of Scientific and Technical Information of China (English)

    马志康; 高原; 蔡航伟; 王成磊; 袁琳; 张焱; 吴炜钦

    2013-01-01

    利用弧光离子镀设备,对201不锈钢表面进行离子沉积TiN薄膜和CrN薄膜.分别在3.5% NaCl溶液、1 mol·L-1NaOH溶液和1 mol·L-1 H2SO4溶液中进行电化学腐蚀性能测试.结果表明,通过弧光离子镀技术在201不锈钢表面分别形成了厚度为1.2 μm的致密TiN薄膜和3μm的致密CrN薄膜;201不锈钢、TiN薄膜和CrN薄膜在3.5%的NaCl溶液中耐蚀性相当;在1mol·L-1的NaOH溶液中,TiN薄膜的耐蚀性约是201不锈钢的2倍,CrN薄膜的耐蚀性是201不锈钢的24倍,TiN薄膜的12倍;在1mol·L-1的H2SO4溶液中,TiN薄膜和CrN薄膜的耐蚀性相比201不锈钢分别提高20倍和26倍.%201 stainless steel was plated with TiN and CrN coatings by arc ion plating.Electrochemical corrosion was tested in 3.5% NaCl solution,1 mol · L-1 NaOH solution and 1 mol · L-1 H2SO4 solution.The results show that 1.2 μm dense TiN coatings and 3μm dense CrN coatings were respectively formed by arc ion plating on the surface of the 201 stainless steel.In 3.5% NaCl solution,the corrosion resistance of TiN coatings and CrN coatings are equitement to that of 201 stainless steel.In 1 mol · L-1 NaOH solution,the corrosion resistance of the TiN coatings was twice of 201 stainless steel.The corrosion resistance of the CrN coatings was about 24 times of 201 stainless steel and 12 times of TiN coatings.In 1 mol · L-1 H2SO4 solution,the corrosion resistance of TiN coatings and CrN coatings strengthen 20 times and 26 times of 201 stainless steel,respectively.

  16. Stainless steels and special grades for specific applications

    International Nuclear Information System (INIS)

    The development of special steels grades with a composition between stainless steels and nickel alloys for localised corrosion resistance applications (steam condenser, combustion products de-pollution...) are shortly presented by family (austenitic and super-austenitic stainless steels of the URANUS family with or without nitrogen additions, austeno-ferritic steels), with electrochemistry corrosion tests evaluation : in standard medium (30 g/l NaCl + 6% FeCl3) or in real medium. (A.B.). 6 refs., 12 figs., 2 tabs

  17. Properties of duplex stainless steels made by powder metallurgy

    OpenAIRE

    M. Rosso; M. Actis Grande; Z. Brytan; L.A. Dobrzański

    2007-01-01

    Purpose: of this paper was to examine the mechanical properties of duplex stainless steels.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies behind the preparation of mixes, Schaeffler’s diagram was taken into consideration. Prepared mixes have been sintered in a vacuu...

  18. Probing the duplex stainless steel phases via magnetic force microscopy

    Science.gov (United States)

    Gheno, S. M.; Santos, F. S.; Kuri, S. E.

    2008-03-01

    Duplex stainless steels are austenitic-ferritic alloys used in many applications, thanks to their excellent mechanical properties and high corrosion resistance. In this work, chemical analyses, x-ray diffraction, and magnetic force microscopy (MFM) were employed to characterize the solution annealed and aged duplex stainless steel. The samples exhibited no changes in lattice parameters and the MFM technique proved successful in clearly imaging the magnetic domain structure of the ferrite phase.

  19. Fatigue curve and stress strain response for stainless steel

    International Nuclear Information System (INIS)

    Applicability of ASME, KTA and RCC-M fatigue design curves for stainless steels is an issue of current debate. Laboratory data have shown environmental effects in coolant waters, but applicability of the proposed new design criteria to current plant components has been questioned. In a Regulatory Guide for new designs, the US NRC endorsed also a new air curve for stainless steels. Aim of the current study is to test applicability of the existing and proposed design criteria

  20. Restorasi Gigi Insisivus Sulung Menggunakan Resin Veneer Mahkota Stainless Steel

    OpenAIRE

    Hilda Shandika P.

    2008-01-01

    Untuk memperbaiki kerusakan gigi yang luas diperlukan restorasi yang tahan lama, retentif, dan estetik. Mahkota stainless steel digunakan untuk merestorasi insisivus sulung yang mengalami karies berat, kelainan bentuk atau akibat trauma. Mahkota ini merupakan restorasi yang kuat, tidak mudah fraktur, dan jarang rusak sampai beberapa tahun selama masih berada di tempatnya. Namun mahkota stainless steel memiliki kekurangan dari segi estetik karena warna peraknya yang mengganggu perhatian pada w...

  1. Thermal fatigue of austenitic and duplex stainless steels

    OpenAIRE

    Virkkunen, Iikka

    2001-01-01

    Thermal fatigue behavior of AISI 304L, AISI 316, AISI 321, and AISI 347 austenitic stainless steels as well as 3RE60 and ACX-100 duplex stainless steels was studied. Test samples were subjected to cyclic thermal transients in the temperature range 20 - 600°C. The resulting thermal strains were analyzed with measurements and numerical calculations. The evolution of thermal fatigue damage was monitored with periodic residual stress measurements and replica-assisted microscopy. The elastic strai...

  2. Corrosion resistance properties of sintered duplex stainless steel

    OpenAIRE

    L.A. Dobrzański; Z. Brytan; M. Actis Grande; M. Rosso

    2006-01-01

    Purpose: of this paper was to examine the corrosion resistance of duplex stainless steels using electrochemical methods in 1M NaCl solution. The influence of powder mixes preparation and cooling cycle after sintering on corrosion properties was evaluated.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the ...

  3. Stainless steel reinforcement for durability in concrete structures

    International Nuclear Information System (INIS)

    Stainless steels and concrete are materials which the nuclear industry, more than any other, has given special attention to over the years. It is the intention of this paper to inform congress about developments outside the nuclear industry, in the use of stainless steel as reinforcement (rebar) in concrete structures. It is left to individual engineers within the industry to assess the implications of this information to applications with which they will be familiar. (author)

  4. Antibacterial properties, corrosion resistance and mechanical properties of Cu-modified SUS 304 stainless steel

    International Nuclear Information System (INIS)

    This investigation studies the effects of Cu content and ageing treatment on the microstructural, mechanical, corrosion and antibacterial properties of SUS 304 austenitic stainless steel. Cu was added respectively to SUS 304 stainless steels in proportions of 1.5, 2.5, 3.5, 4.5 and 5.5 wt.%. A vacuum arc remelting furnace was used to remelt SUS 304 stainless steel with various added Cu contents. These ingot alloys underwent hot rolling and various heat treatments, and were then cut into test specimens. A series of microstructural investigation, tensile tests, corrosion tests and antibacterial tests were conducted to study the properties of Cu-containing SUS 304 austenitic stainless steel. Microstructural observations reveal that the amount of retained δ-ferrite in the as-cast SUS 304 steel decreases as the Cu content increases. After hot rolling, the retained δ-ferrite disappears and α'-martensite forms in the austenitic matrix. The results of the tensile tests reveal that the ultimate tensile strength (UTS) declines as the Cu content increases below 2.5 wt.%. However, the ultimate tensile strength increases with the Cu content above 2.5 wt.%. X-ray diffraction analysis reveals that adding Cu suppresses the formation of strain-induced martensite (α'-martensite). The corrosion test indicates that the pitting potential declines as the Cu content in SUS 304 steels increases. The results of the antibacterial test reveal that adding a proper amount of Cu (such as 2 wt.%) gives SUS 304 stainless steel an excellent antibacterial property

  5. Comprehensive Study ol) Principle of High-strength Stainless Steel Arc Strip in Cold-forming%高强度不锈钢弧形板冷弯成形机理的集成研究

    Institute of Scientific and Technical Information of China (English)

    楚志兵; 马立峰; 黄庆学; 闫志杰; 潘海彦; 潘丽君

    2012-01-01

    不锈钢弧形板具有耐腐蚀、强度高、光洁美观等优点,因此在地铁和高铁的建设中得到广泛应用。但因其尺寸精度要求高,导致成形工艺难度大,从而制约了工业的生产。针对此问题,以符拉索夫开口薄壁梁理论为基础,推导出符合高强度不锈钢弧形板成形弯曲角度表达式及横向变形及纵向变形的能量计算式,并编制出成形工艺。之后建立服役行为的数学模型,通过模拟轧制力大小及不锈钢弧形板成形后的回弹量来判定理论道次变形量分配的合理性。对合作企业现有冷弯成形机组改造,依据最优仿真结果进行实验,反复修正后的工艺模型能顺利辊弯出高强度不锈钢弧形板产品,且现场测试数据显示,机组的轧制力能稳定,成形后的回弹量较小,产品质量满足用户精度要求。对形成最优成形工艺,提高辊弯质量和精度有重要作用。%Based on Vlasov open-profile thin-walled beam theory, bending angle expression consistent with high-strength stainless arc strip, energy equations of transverse and longitudinal deformation were deduced and process planning was obtained. The mathematical model of service behavior was established and the rolling force and spring back value after stainless arc strip being formed were simula- ted to judge the distribution reasonability of theoretical pass deformation. Depending on improved cold-roll forming equipment of cooper- ative enterprise and optimum simulation results, after several modification, high-strength stainless arc strip was roiled favorably, and testing result in site indicated that spring-back amount after forming is small and product quality could meet precision requirement of the users. Therefore the synthesis study on high-strength stainless arc strip of cold-bending principle is of great significance to optimum pro- cessing technology, bending roller quality and precision.

  6. Narrow Gap Laser Welding of 316L Stainless Steel for Potential Application in the Manufacture of Thick Section Nuclear Components

    OpenAIRE

    Elmesalamy, Ahmed

    2013-01-01

    Thick-section austenitic stainless steels have widespread industrial applications, especially in nuclear power plants. The joining methods used in the nuclear industry are primarily based on arc welding processes. However, it has recently been shown that the Narrow Gap Laser Welding (NGLW) technique can be used to join materials with thicknesses that are well beyond the capabilities of single pass autogenous laser welding. The heat input for NGLW is much lower than that of arc welding, as are...

  7. 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.

  8. Weld solidification cracking in 304 to 304L 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; 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.

  9. The electrochemistry of 13% chromium stainless steel in oilfield brines

    Energy Technology Data Exchange (ETDEWEB)

    Sidorin, Dmitry; Pletcher, Derek [Department of Chemistry, The University of Southampton, Southampton SO17 1BJ (United Kingdom); Hedges, Bill [BP Trinidad Ltd., P.O. Box 714, Port of Spain (Trinidad and Tobago)

    2005-07-25

    The electrochemistry of a 13% Cr stainless steel (API5CT L80-13Cr) in 3% NaCl containing acetate and either acetic acid or carbon dioxide at 333 K is explored using RDE voltammetry. The reduction of proton, carbonic acid and acetic acid occur simultaneously, immediately negative to the corrosion potential. Acetic acid gives a well formed reduction wave and the current densities increase with the equilibrium concentration of acetic acid in the medium; in the plateau region, the reduction is mass transport controlled. Despite this reduction process, the corrosion resistance and passivation current density are independent of the acetic acid concentration. It is confirmed that the 13% Cr stainless steel is much more resistant to corrosion that X65 carbon steel and, unlike the carbon steel, its rate of corrosion does not vary with acetic acid concentration. The properties of the passivating film appear to dominate the behaviour of the 13% Cr stainless steel. (author)

  10. The electrochemistry of 13% chromium stainless steel in oilfield brines

    International Nuclear Information System (INIS)

    The electrochemistry of a 13% Cr stainless steel (API5CT L80-13Cr) in 3% NaCl containing acetate and either acetic acid or carbon dioxide at 333 K is explored using RDE voltammetry. The reduction of proton, carbonic acid and acetic acid occur simultaneously, immediately negative to the corrosion potential. Acetic acid gives a well formed reduction wave and the current densities increase with the equilibrium concentration of acetic acid in the medium; in the plateau region, the reduction is mass transport controlled. Despite this reduction process, the corrosion resistance and passivation current density are independent of the acetic acid concentration. It is confirmed that the 13% Cr stainless steel is much more resistant to corrosion that X65 carbon steel and, unlike the carbon steel, its rate of corrosion does not vary with acetic acid concentration. The properties of the passivating film appear to dominate the behaviour of the 13% Cr stainless steel

  11. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  12. Final Report, Volume 1, Metallurgical Evaluation of Cast Duplex Stainless Steels and their Weldments

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Songqing; Lundin, Carl, W.; Batten, Greg, W.

    2005-09-30

    Duplex stainless steels (DSS) are being specified for chloride containing environments due to their enhanced pitting and stress corrosion cracking resistance. They exhibit improved corrosion performance over the austenitic stainless steels. Duplex stainless steels also offer improved strength properties and are available in various wrought and cast forms. Selected grades of duplex stainless steel castings and their welds, in comparison with their wrought counterparts, were evaluated, regarding corrosion performance and mechanical properties and weldability. Multiple heats of cast duplex stainless steel were evaluated in the as-cast, solution annealed (SA) static cast and SA centrifugal cast conditions, while their wrought counterparts were characterized in the SA condition and in the form of as-rolled plate. Welding, including extensive assessment of autogenous welds and a preliminary study of composite welds (shielded metal arc weld (SMAW)), was performed. The evaluations included critical pitting temperature (CPT) testing, intergranular corrosion (IGC) testing, ASTM A923 (Methods A, B and C), Charpy impact testing, weldability testing (ASTM A494), ferrite measurement and microstructural evaluations. In the study, the corrosion performances of DSS castings were characterized and assessed, including the wrought counterparts for comparison. The evaluation filled the pore of lack of data for cast duplex stainless steels compared to wrought materials. A database of the pitting corrosion and IGC behavior of cast and wrought materials was generated for a greater depth of understanding for the behavior of cast duplex stainless steel. In addition, improved evaluation methods for DSS castings were developed according to ASTM A923, A262, G48 and A494. The study revealed that when properly heat treated according to the specification, (1) DSS castings have equal or better pitting and intergranular corrosion resistance than their wrought counterparts; (2) Welding reduces the

  13. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    OpenAIRE

    Prabhu Paulraj; Rajnish Garg

    2015-01-01

    Duplex Stainless Steels (DSS) and Super Duplex Stainless Steel (SDSS) have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic pha...

  14. Plasma spot welding of ferritic stainless steels

    Directory of Open Access Journals (Sweden)

    Lešnjak, A.

    2002-06-01

    Full Text Available Plasma spot welding of ferritic stainless steels is studied. The study was focused on welding parameters, plasma and shielding gases and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared. Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas, i.e., a 98 % Ar/2 % H 2 gas mixture. Tension-shear strength of plasma-spot welded joints was compared to that of resistance-spot welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a larger weld spot diameter of the former. Strength of both types of welded joints is approximately the same.

    El artículo describe el proceso de soldeo de aceros inoxidables ferríticos por puntos con plasma. La investigación se centró en el establecimiento de los parámetros óptimos de la soldadura, la definición del gas de plasma y de protección más adecuado, así como del equipo óptimo para la realización de la soldadura. Las uniones de láminas de aceros inoxidables ferríticos de 0,8 mm de espesor, soldadas a solape por puntos con plasma, se inspeccionaron visualmente y se ensayaron mecánicamente mediante el ensayo de cizalladura por tracción. Se realizaron macro pulidos. Los resultados de la investigación demostraron que la solución más adecuada para el soldeo por puntos con plasma es elegir el mismo gas de plasma que de protección. Es decir, una mezcla de 98 % de argón y 2 % de hidrógeno. La resistencia a la cizalladura por tracción de las uniones soldadas por puntos con plasma fue comparada con la resistencia de las uniones soldadas por resistencia por puntos. Se llegó a la conclusión de que las uniones soldadas por resistencia soportan una carga algo mayor que la uniones

  15. Effect of welding processes on corrosion resistance of UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    An attractive combination of corrosion resistance and mechanical properties in the temperature range -50 to 250 .deg. C is offered by duplex stainless steel. However, undesirable secondary precipitation phase such as σ, γ2 and Cr2N may taken place at the cooling stage from the welding processes. Therefore, this paper describes the influence of different welding procedures such as manual metal arc welding (MMA), tungsten inert gas welding (TIG) and vacuum brazing on corrosion resistance of the welded joint for UNS S31803 duplex stainless steel. Microstructure and chemical compositions of the welded joint were examined. The weight loss of specimens immersed in 6% FeCl3 solution at 47.5 .deg. C for 24-hours was determined and used to evaluate the pitting resistance of duplex stainless steel and their welds. The region of heat-affected zone of specimen obtained by the MMA is much wider than that resulted from TIG, therefore, the weight loss of welds by MMA was larger than that of weld by TIG. The weight loss of brazed specimens cooled from slow cooling rate was larger than those of specimens cooled from high cooling rate, because the precipitation of σ phase. Beside that, the weight loss of brazed specimen is greater than those of the welded specimens. The galvanic corrosion was observed in brazed duplex stainless steel joints in the chloride solution

  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...

  17. Martensite transformation in antimony implanted stainless steel

    International Nuclear Information System (INIS)

    The authors have used Rutherford backscattering analysis (RBS) and transmission electron microscopy (TEM) and diffraction to investigate austenitic stainless steel crystals implanted at room temperature with 80 keV Sb+ ions to a fluence of 5 x 1020 ions/m2, thus providing implantation with a heavy group V element. RBS channeling spectra from implanted crystals show a damage peak which approaches the height of the random level and therefore indicates a very high degree of disorder in the implanted layers. The distribution of the disorder extends to a depth 3-5 times the depth of the primary radiation damage. The Sb peaks under channeling as well as random conditions are indistinguishable, confirming that substitutionality during implantation is negligible. To establish the nature of the disorder which cannot be assessed from the RBS analysis alone, and in particular to assess whether an amorphous alloy is formed in the implanted layer as indicated from the RBS spectra, samples implanted under similar conditions were investigated in the TEM. Significant extra spots in the patterns can be ascribed to the presence of a radiation induced b.c.c. phase of martensitic origin. The result that a significant amount of martensite can be induced by antimony implantation seems to indicate that the main driving force for the transition is due to damage induced stress concentrations. (Auth.)

  18. 混合保护气体成分对不锈钢气保焊焊缝成形的影响%The Influence of Composition of Mixed Shielding Gas on the Weld Appearance of Stainless Steel Gas Shield Arc Welding

    Institute of Scientific and Technical Information of China (English)

    王博

    2012-01-01

    This paper studies the effect of difference of shielding gas composition and proportion of stainless steel melting pole gas shield arc welding on weld appearance, analyzes the advantages and disadvantages of different gases, in order to provide a strong basis for rationally using shielding gas composition and accessing good weld.%本文研究不锈钢熔化极气保焊保护气体成分与比例不同对焊缝成形的影响,分析了不同气体的优缺点,为合理选用保护气体成分、获得优良的焊缝成形提供了有力的依据.

  19. Corrosion behavior of duplex stainless steel in sulphuric acid

    International Nuclear Information System (INIS)

    Duplex stainless steels are alloyed and processed to develop microstructure of roughly equal amounts of ferrite and austenite. Duplex stainless steel constitute a new class of materials because they have balanced amounts of ferrite and austenite. Since they have high content of chromium and molybdenum present, thus they have good corrosion resistance. Their corrosion resistance is double to that of annealed austenitic stainless steels with regard to pitting, crevice corrosion, sulphide stress corrosion, and chloride stress corrosion environments. The corrosion behavior of duplex stainless steel in various concentrations of sulphuric acid was studied. The reactions were carried out by placing the steel specimen in a beaker containing a known concentration of sulphuric acid at room temperature for a definite period. Pits were initiated in duplex stainless steel specimen and the propagation of pits depends upon the concentration of the acid solution in which the sample is in contact. The weight loss for definite period of time were measured and corrosion rates were calculated in millimetres per year. The corrosion rates increases with an increase in acid concentration at room temperature. A comparison of the results obtained from various concentrations of sulphuric acid with the same concentrations of nitric acid is also discussed. (author)

  20. Stainless steel tube-based cell cryopreservation containers.

    Science.gov (United States)

    Shih, Wei-Hung; Yu, Zong-Yan; Wu, Wei-Te

    2013-12-01

    This study focused on increasing the freezing rate in cell vitrification cryopreservation by using a cryopreservation container possessing rigid mechanical properties and high heat-transfer efficiency. Applying a fast freezing rate in vitrification cryopreservation causes a rapid temperature change in the cryopreservation container and has a substantial impact on mechanical properties; therefore, a highly rigid cryopreservation container that possesses a fast freezing rate must be developed. To produce a highly rigid cryopreservation container possessing superior heat transfer efficiency, this study applies an electrochemical machining (ECM) method to an ANSI 316L stainless steel tube to treat the surface material by polishing and roughening, thereby increasing the freezing rate and reducing the probability of ice crystal formation. The results indicated that the ECM method provided high-quality surface treatment of the stainless steel tube. This method can reduce internal surface roughness in the stainless steel tube, thereby reducing the probability of ice crystal formation, and increase external surface roughness, consequently raising convection heat-transfer efficiency. In addition, by thinning the stainless steel tube, this method reduces heat capacity and thermal resistance, thereby increasing the freezing rate. The freezing rate (3399 ± 197 °C/min) of a stainless steel tube after interior and exterior polishing and exterior etching by applying ECM compared with the freezing rate (1818 ± 54 °C/min) of an original stainless steel tube was increased by 87%, which also exceeds the freezing rate (2015 ± 49 °C/min) of an original quartz tube that has a 20% lower heat capacity. However, the results indicated that increasing heat-transferring surface areas and reducing heat capacities cannot effectively increase the freezing rate of a stainless steel tube if only one method is applied; instead, both techniques must be implemented concurrently to improve the

  1. Modern high strength QT, TM and duplex-stainless steels

    International Nuclear Information System (INIS)

    Pressure vessels are commonly manufactured with normalised steel grades with a yield strength up to 355 MPa or with austenitic stainless steels when corrosion as to be considered. From three decades, modern steels with higher mechanical properties - up to yield strength of 960 Mpa - are available and largely used for other applications where weight saving is of major importance as per off-shore, bridges, cranes, shipbuilding, line pipes.. The paper presents these modern steel's families - TMCP (Thermo Mechanically Controlled Process), QT (Quenched and Tempered) and Duplex (austeno-ferritic) stainless - in comparison with the normalised and austenitic steel grades. The following aspects are presented: the main mechanical properties (tensile and Charpy) as per the requirements of the standards for pressure equipment; some examples of use of these modern steels in the industry are given; the limitations of the forming conditions are considered; the weldability aspects and welds properties are developed; the interest of the PWHT (Post Weld Heat Treatment) is discussed. (orig.)

  2. 77 FR 28568 - Grant of Authority for Subzone Status; North American Stainless, (Stainless Steel), Ghent, KY

    Science.gov (United States)

    2012-05-15

    ... public comment has been given in the Federal Register (76 FR 66684-66685, 10-27-2011) and the application... Steel), Ghent, KY Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as... authority to establish a special-purpose subzone at the stainless steel mill of North American...

  3. Study on microstructure and mechanical characteristics of low-carbon steel and ferritic stainless steel joints

    Energy Technology Data Exchange (ETDEWEB)

    Sarkari Khorrami, Mahmoud; Mostafaei, Mohammad Ali; Pouraliakbar, Hesam, E-mail: hpouraliakbar@alum.sharif.edu; Kokabi, Amir Hossein

    2014-07-01

    In this work, examinations on the microstructure and mechanical properties of plain carbon steel and AISI 430 ferritic stainless steel dissimilar welds are carried out. Welding is conducted in both autogenous and using ER309L austenitic filler rod conditions through gas tungsten arc welding process. The results indicate that fully-ferritic and duplex ferritic–martensitic microstructures are formed for autogenous and filler-added welds, respectively. Carbide precipitation and formation of martensite at ferrite grain boundaries (intergranular martensite) as well as grain growth occur in the heat affected zone (HAZ) of AISI 430 steel. It is found that weld heat input can strongly affect grain growth phenomenon along with the amount and the composition of carbides and intergranular martensite. Acquired mechanical characteristics of weld in the case of using filler metal are significantly higher than those of autogenous one. Accordingly, ultimate tensile strength (UTS), hardness, and absorbed energy during tensile test of weld metal are increased from 662 MPa to 910 MPa, 140 Hv to 385 Hv, and 53.6 J m{sup −3} to 79 J m{sup −3}, respectively by filler metal addition. From fracture surfaces, predominantly ductile fracture is observed in the specimen welded with filler metal while mainly cleavage fracture occurs in the autogenous weld metal.

  4. 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.

  5. Welding stainless steels for structures operating at liquid helium temperature

    International Nuclear Information System (INIS)

    Superconducting magnets for fusion energy reactors require massive monolithic stainless steel weldments which must operate at extremely low temperatures under stresses approaching 100 ksi (700 MPa). A three-year study was conducted to determine the feasibility of producing heavy-section welds having usable levels of strength and toughness at 4.20K for fabrication of these structures in Type 304LN plate. Seven welding processes were evaluated. Test weldments in full-thickness plate were made under severe restraint to simulate that of actual structures. Type 316L filler metal was used for most welds. Welds deposited under some conditions and which solidify as primary austenite have exhibited intergranular embrittlement at 4.20K. This is believed to be associated with grain boundary metal carbides or carbonitrides precipitated during reheating of already deposited beads by subsequent passes. Weld deposits which solidify as primary delta ferrite appear immune. Through use of fully austenitic filler metals of low nitrogen content under controlled shielded metal arc welding conditions, and through use of filler metals solidifying as primary delta ferrite where only minimum residuals remain to room temperature, welds of Type 316L composition have been made with 4.2K yield strength matching that of Type 304LN plate and acceptable levels of soundness, ductility and toughness

  6. Antibacterial and corrosive properties of copper implanted austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    Juan Xiong; Bo-fan Xu; Hong-wei Ni

    2009-01-01

    Copper ions were implanted into austenitic stainless steel (SS) by metal vapor vacuum arc with a energy of 100 keV and an ions dose range of (0.5-8.0)x 1017 cm-2. The Cu-implanted SS was annealed in an Ar atmosphere furnace. Glancing X-ray diffraction (GXRD), transmission electron microscopy (TEM) and Auger electron spectroscopy (AES) were used to reveal the phase com-positions, microstructures, and concentration profiles of copper ions in the implanted layer. The results show that the antibacterialproperty of Cu-implanted SS is attributed to Cu9.9Fe0.1 which precipitated as needles. The depth of copper in Cu-implanted SS with annealing treatment is greater than that in Cu-implanted SS without annealing treatment, which improves the antibacterial property against S. Aureus. The salt wetting-drying combined cyclic test was used to evaluate the corrosion-resistance of antibacterial SS, and the results reveal that the antibacterial SS has a level of corrosion-resistance equivalent to that of un-implanted SS.

  7. Fracture toughness of a welded super duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Pilhagen, Johan, E-mail: pilhagen@kth.se [Department of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden); Sieurin, Henrik [Scania CV AB, Södertälje (Sweden); Sandström, Rolf [Department of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm (Sweden)

    2014-06-01

    Fracture toughness testing was conducted on standard single-edge notched bend bar specimens of base and weld metal. The material was the SAF 2906 super duplex stainless steel. The aim was to evaluate the susceptibility for brittle failure at sub-zero temperatures for the base and weld metal. The base metal was tested between −103 and −60 °C and was evaluated according to the crack-tip opening displacement method. The fracture event at and below −80 °C can be described as ductile until critical cleavage initiation occurs, which caused unstable failure of the specimen. The welding method used was submerged arc welding with a 7 wt% nickel filler metal. The welded specimens were post-weld heat treated (PWHT) at 1100 °C for 20 min and then quenched. Energy-dispersive X-ray spectroscopy analysis showed that during PWHT substitutional element partitioning occurred which resulted in decreased nickel content in the ferrite. The PWHT weld metal specimens were tested at −72 °C. The fracture sequence was critical cleavage fracture initiation after minor crack-tip blunting and ductile fracture.

  8. Fracture toughness of a welded super duplex stainless steel

    International Nuclear Information System (INIS)

    Fracture toughness testing was conducted on standard single-edge notched bend bar specimens of base and weld metal. The material was the SAF 2906 super duplex stainless steel. The aim was to evaluate the susceptibility for brittle failure at sub-zero temperatures for the base and weld metal. The base metal was tested between −103 and −60 °C and was evaluated according to the crack-tip opening displacement method. The fracture event at and below −80 °C can be described as ductile until critical cleavage initiation occurs, which caused unstable failure of the specimen. The welding method used was submerged arc welding with a 7 wt% nickel filler metal. The welded specimens were post-weld heat treated (PWHT) at 1100 °C for 20 min and then quenched. Energy-dispersive X-ray spectroscopy analysis showed that during PWHT substitutional element partitioning occurred which resulted in decreased nickel content in the ferrite. The PWHT weld metal specimens were tested at −72 °C. The fracture sequence was critical cleavage fracture initiation after minor crack-tip blunting and ductile fracture

  9. Experimental study on the emissivity of stainless steel

    International Nuclear Information System (INIS)

    The emissivity of material is a very important parameter for thermal radiative heat transfer. The emissivities of stainless steel 316L and 304 were measured as a fuction of surface temperature and heating time of test section by indirect method using the infrared thermometer. The error range of experiment is within 3∼10% and most of errors were occurred in measuring the surface temperature by thermocouple. The range of temperature for the experiment was 50∼540.deg. C and the emissivities of stainless steel 316L and 304 were increased along with the increase of surface temperature, and the increase rates for two materials were approximately the same and the value was about 1.31x10-4(1/.deg. C). The emissivity of stainless steel 316L with surface roughness 4.1μm was between 0.44 and 0.51, and the emissivity of stainless steel 304 with surface roughness 2.0μm was between 0.32 and 0.38 in this temperature range. The emissivity of stainless steel 304 was gradually increased by a value of 0.03 at 395.deg. C for 266 hours

  10. Aging of cast duplex stainless steels in LWR systems

    International Nuclear Information System (INIS)

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are evaluated to determine the expected embrittlement of cast components during the operating lifetime of reactors and to define the objectives and scope of the investigation. This presentation describes the status of the program. Data for the metallurgical characterization of the various cast stainless steels used in the investigation are presented. Charpy impact tests on short-term aged material indicate that CF-3 stainless steels are less susceptible to embrittlement than CF-8 or CF-8M stainless steels. Microstructural characterization of cast stainless steels that were obtained from Georg Fischer Co. and aged for up to 70,000 h at 300, 350, and 4000C reveals the formation of four different types of precipitates that are not α'. Embrittlement of the ferrite phase is primarily due to pinning of the dislocations by two of these precipitates, designated as Type M and Type X. The ferrite phase is embrittled after approx. 8 y at 3000C and shows cleavage fracture. Examination of the fracture surfaces of the impact-test specimens indicates that the toughness of the long-term aged material is determined by the austenite phase. 8 figures, 3 tables

  11. Creep, thermal-cyclic and tensile properties of Nb-1Zr to stainless steel transition joints

    International Nuclear Information System (INIS)

    Joining of Nb-1Zr to austenitic type 316 stainless steel (SS) was investigated. Gas tungsten arc welding was conducted on sheet metals and tubing by lap welding 316 SS over Nb-1Zr. Sound welds were produced by controlling heat input and through careful surface preparation. Satisfactory strength and ductility of the welded joints were found in the tensile tests at room temperature and 1000 K. Investigation of thermocycling effects showed that there was a small degradation in the mechanical properties of the joint after 100 thermal cycles between 300 and 1000 K under vacuum. Creep tests were performed on welded tubing joints at a temperature of 1000 K with internal pressures up to 6.9 MPa. Creep test results show that the welded joint has higher creep resistance than stainless steel. Furthermore, to improve the toughness of the Nb-1Zr to 316 SS weld, the use of a vanadium interlayer was investigated. ((orig.))

  12. Compresibility and sinterability of HCx PM steel diluted with stainless steels

    OpenAIRE

    Gordo Elena; Khattab Nermein Hamid; Ruiz-Navas Elisa María

    2003-01-01

    HCx powder metallurgy steel contains in its composition high contents of Cr and C, and significant quantities of alloy elements typical of tool steels (Mo, V, W), to provide the corrosion resistance of stainless steel with wear resistance of tool steels. HCx appears to be a suitable material for applications in aggressive environments, as valve seat inserts in automotive engines. However, this steel presents a low compressibility leading to high production costs. In this work, some results ca...

  13. Operational experience of stainless steels in seawater-cooled systems

    International Nuclear Information System (INIS)

    A study has been made of chiefly Swedish and Finnish operational experience of stainless steel in seawater and brackish water. A report is given on 23 typical cases, behind which in actual fact a considerably larger number of individual practical cases are concealed. The answer to the primary question why a standard steel of type SS 2343 (AISI 316) sometimes, contrary to expectation, remains unattacked by local corrosion is that there is usually spontaneous cathodic protection by other less noble components of carbon steel, cast iron or some copper alloy in direct contact with the stainless steel. The study confirms in other respects the adverse effect of residual oxides after welding and the beneficial of low temperature, high continuous waterflow and periodic cleaning, and of rinsing with fresh water during out-of service periods. It also verifies the additional advantages of the new high-alloy special steels which have begun to be marketed in recent years for seawater applications. (author)

  14. Tensile properties of the modified 13Cr martensitic stainless steels

    Science.gov (United States)

    Mabruri, Efendi; Anwar, Moch. Syaiful; Prifiharni, Siska; Romijarso, Toni B.; Adjiantoro, Bintang

    2016-04-01

    This paper reports the influence of Mo and Ni on the tensile properties of the modified 13Cr martensitic stainless steels in tempered condition. Four steels with different content of Mo and Ni were prepared by induction melting followed by hot forging, quenching and tempering. The experimental results showed that the addition of about 1% and 3% Mo has a beneficial effect to increase both the tensile strength and the elongation of the steels. On the contrary, the addition of about 3% Ni into the martensitic stainless steel results in decreasing of both the tensile strength and the elongation. Among the alloys investigated the 13Cr3Mo type steel exhibited largest tensile strength of 1348 MPa and largest elongation of 12%. The observation on the tensile fractured surfaces by using scanning electron microscope supported these findings.

  15. Thermal Induced Processes in Laminar System of Stainless Steel - Beryllium

    International Nuclear Information System (INIS)

    The paper reports on investigation of the laminar system 'stainless steel 12Cr18Ni10Ti - Be' at thermal treatment. There have been determined sequences of phase transformations along with relative amount of iron-containing phases in the samples subjected to thermal beryllization. It has been revealed that thermal beryllization of stainless steel thin foils results in γ→α transformation and formation of the beryllides NiBe and FeBe2. It has also been revealed that direct γ→α- and reverse α→γ-transformations are accompanied by, correspondingly, formation and decomposition of the beryllide NiBe. It is shown that distribution of the formed phases within sample bulk is defined by local concentration of beryllium. Based on obtained experimental data there is proposed a physical model of phase transformations in stainless steel at thermal beryllization.

  16. Depth distribution of martensite in xenon implanted stainless steels

    International Nuclear Information System (INIS)

    The amount of stress-induced martensite and its distribution in depth in xenon implanted austenitic stainless steel poly- and single crystals have been measured by Rutherford backscattering and channeling analysis, depth selective conversion electron Moessbauer spectroscopy, cross-sectional transmission electron microscopy and x-ray diffraction analysis. In low nickel 17/7, 304 and 316 commercial stainless steels and in 17:13 single crystals the martensitic transformation starts at the surface and develops towards greater depth with increasing xenon fluence. The implanted layer is nearly completely transformed, and the interface between martensite and austenite is rather sharp and well defined. In high nickel 310 commercial stainless steel and 15:19 and 20:19 single crystals, on the other hand, only insignificant amounts of martensite are observed. (orig.)

  17. Highly robust stainless steel tips as microelectrospray emitters.

    Science.gov (United States)

    Ishihama, Yasushi; Katayama, Hiroyuki; Asakawa, Naoki; Oda, Yoshiya

    2002-01-01

    Tapered stainless steel spray tips for sheathless microelectrospray ionization (microESI) have been developed. The fabrication procedure for the tapered stainless steel tips was optimized using an electropolishing technique followed by removal of the burr. Using the tip as the microESI emitter, a stable ESI spray was obtained at a flow rate of 20 nL/min. The sensitivity of the microESI system was almost two orders greater than that of the conventional ion spray system. The tip was highly stable, and was successfully used for over 1000 h. Moreover, these stainless steel tips were suitable for use with sheathless capillary electrophoresis/mass spectrometry (CE/MS) and capillary liquid chromatography/mass spectrometry (LC/MS) for routine analysis in proteomic and pharmaceutical applications. PMID:11968120

  18. Microbially influenced corrosion of stainless steels in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, U.P.; Wolfram, J.H.; Rogers, R.D.

    1990-01-01

    This paper reviews the components, causative agents, corrosion sites, and potential failure modes of stainless steel components susceptible to microbially influenced corrosion (MIC). The stainless steel components susceptible to MIC are located in the reactor coolant, emergency, and reactor auxiliary systems, and in many plants, in the feedwater train and condenser. The authors assessed the areas of most high occurrence of corrosion and found the sites most susceptible to MIC to the heat-affected zones in the weldments of sensitized stainless steel. Pitting is the predominant MIC corrosion mechanisms, caused by sulfur reducing bacteria (SRB). Also discussed is the current status of the diagnostic, preventive, and mitigation techniques, including use of improved water chemistry, alternate materials, and improved thermomechanical treatments. 37 refs., 3 figs.

  19. Embrittlement of cast stainless steels in LWR systems

    International Nuclear Information System (INIS)

    Mechanical property data from Charpy-impact and J-R curve tests are presented for several experimental and commercial heats, as well as reactor-aged material of CF-3, CF-8, and CF-8M grades of cast stainless steel. The effects of material variables on the embrittlement of cast stainless steels are evaluated. The chemical composition and ferrite morphology have a strong effect on the extent and kinetics of embrittlement. The data are analyzed to establish the mechanisms of embrittlement. The procedure and correlations for predicting the impact strength and fracture toughness of cast components during reactor service are described. The lower bound values of impact strength and fracture toughness for low-temperature aged cast stainless steel are defined. 13 refs., 13 figs., 3 tabs

  20. Evaluation of Additive Manufacturing for Stainless Steel Components

    Energy Technology Data Exchange (ETDEWEB)

    Peter, William H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lou, Xiaoyuan [General Electric (GE), Wilmington, NC (United States); List, III, Frederick Alyious [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Webber, David [General Electric (GE), Wilmington, NC (United States)

    2016-09-01

    This collaboration between Oak Ridge National Laboratory and General Electric Company aimed to evaluate the mechanical properties, microstructure, and porosity of the additively manufactured 316L stainless steel by ORNL’s Renishaw AM250 machine for nuclear application. The program also evaluated the stress corrosion cracking and corrosion fatigue crack growth rate of the same material in high temperature water environments. Results show the properties of this material to be similar to the properties of 316L stainless steel fabricated additively with equipment from other manufacturers with slightly higher porosity. The stress corrosion crack growth rate is similar to that for wrought 316L stainless steel for an oxygenated high temperature water environment and slightly higher for a hydrogenated high temperature water environment. Optimized heat treatment of this material is expected to improve performance in high temperature water environments.

  1. Mechanical properties of duple stainless steels laser joints

    International Nuclear Information System (INIS)

    The welded joints of stainless steels always present problems for the microstructural modifications that occur in the heat affected zone. Particularly, duplex stainless steels present very important changes when the weld pool solidifies forming fundamentally ferritic structures with some austenite in grain boundaries. These microstructural modifications, and those which occur in the HAZ, justify the mechanical properties of the joint and mainly those of plasticity, being all of them influenced by the processing conditions. In this work the influence of the laser welding speed on the tensile behaviour od duplex stainless steel welded joints is presented. The microstructure of the obtained seams and of the heat affected zone will be evaluated by means of optic and scanning electron microscopy. Also, different microhardness profiles have been obtained to evaluate the modifications in the mechanical properties both in the seam and the zone of thermal affection. (Author) 23 refs

  2. Variation and optimization of acid-dissolved aluminum content in stainless steel

    Science.gov (United States)

    Zhang, Le-chen; Bao, Yan-ping; Wang, Min; Zhang, Chao-jie

    2016-04-01

    As a key step in secondary refining, the deoxidation process in clean stainless steel production is widely researched by many scholars. In this study, vacuum oxygen decarburization (VOD) deoxidation refining in a 40-t electric arc furnace + VOD + ingot casting process was analyzed and optimized on the basis of Al deoxidation of stainless steel and thermodynamic equilibrium reactions between the slag and steel. Under good stirring conditions in VOD, the deoxidation reaction reaches equilibrium rapidly, and the oxygen activity in the bulk steel is controlled by the slag composition and Al content. A basicity of 3-5 and an Al content greater than 0.015wt% in the melt resulted in an oxygen content less than 0.0006wt%. In addition, the dissolved oxygen content decreased slightly when the Al content in the steel was greater than 0.02wt%. Because of the equilibrium of the Si-O reaction between the slag and steel, the activity of SiO2 will increase while the Si content increases; thus, the Si content should be lowered to enable the formation of a high-basicity slag. A high-basicity, low-Al2O3 slag and an increased Si content will reduce the Al consumption caused by SiO2 reduction.

  3. 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.

  4. Sinter-hardening process applicable to stainless steels

    Directory of Open Access Journals (Sweden)

    M. Rosso

    2007-10-01

    Full Text Available Purpose: of this paper was to describe sintered duplex stainless steels manufactured in sinter-hardening process and its usability in field of stainless steels.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, ferritic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies apart from the preparation of mixes, Schaeffler’s diagram was taken into consideration. Prepared mixes have been compacted at 800 MPa and sintered in a vacuum furnace with argon backfilling at temperatures from 1200°C to 1285°C for 0.5, 1 and 2 h. After sintering different cooling cycles were applied using nitrogen under pressure from 0.6 MPa to 0.002 MPa in argon atmosphere. Produced duplex stainless steels have been studied by scanning and optical microscopy and EDS chemical analysis of microstructure components.Findings: Obtained microstructure and mechanical properties of sintered duplex stainless steel strictly depend on the density and the pore morphology present in the microstructure and especially on cooling rate directly from sintering temperature in sinter-hardening process. The lowest cooling rate - applied gas pressure, the mechanical properties and corrosion resistance decrease due to precipitation of sigma phase. Proper bi-physic microstructure was obtained using nitrogen under pressure of 0.6 and 0.2 MPa.Research limitations/implications: Applied fast cooling rate seems to be a good compromise for mechanical properties and obtained microstructures, nevertheless further tests should be carried out in order to examine its influence on corrosion properties.Originality/value: The utilization of sinter-hardening process combined with use of elemental powders added to a stainless steel base powder shows its potentialities in terms of good microstructural homogeneity and especially working with cycles possible to introduce in

  5. Failure of austenitic stainless steel tubes during steam generator operation

    OpenAIRE

    M. Głowacka; J. Łabanowski; S. Topolska

    2012-01-01

    Purpose: of this study is to analyze the causes of premature failure of steam generator coil made of austenitic stainless steel. Special attention is paid to corrosion damage processes within the welded joints.Design/methodology/approach: Examinations were conducted several segments of the coil made of seamless cold-formed pipes Ø 23x2.3 mm, of austenitic stainless steel grade X6CrNiTi18-10 according to EN 10088-1:2007. The working time of the device was 6 months. The reason for the withdrawa...

  6. Fatigue behavior of welded austenitic stainless steel in different environments

    OpenAIRE

    D. S. Yawas; S.Y. Aku; S.O. Aluko

    2014-01-01

    The fatigue behavior of welded austenitic stainless steel in 0.5 M hydrochloric acid and wet steam corrosive media has been investigated. The immersion time in the corrosive media was 30 days to simulate the effect on stainless steel structures/equipment in offshore and food processing applications and thereafter annealing heat treatment was carried out on the samples. The findings from the fatigue tests show that seawater specimens have a lower fatigue stress of 0.5 × 10−5 N/mm2 for the heat...

  7. Impact toughness of tungsten films deposited on martensite stainless steel

    Institute of Scientific and Technical Information of China (English)

    HUANG Ning-kang; YANG Bin; WANG De-zhi

    2005-01-01

    Tungsten films were deposited on stainless steel Charpy specimens by magnetron sputtering followed by electron beam heat treatment. Charpy impact tests and scanning electron microscopy were used to investigate the ductile-brittle transition behavior of the specimens. With decreasing test temperature the fracture mode was transformed from ductile to brittle for both kinds of specimens with and without W films. The data of the crack initiation energy, crack propagation energy, impact absorbing energy, fracture time and deflection as well as the fracture morphologies at test temperature of -70 ℃ show that W films can improve the impact toughness of stainless steel.

  8. Corrosion induced by cathodic hydrogen in 2205 duplex stainless steel

    Science.gov (United States)

    Michalska, J.

    2011-05-01

    In this work new results about the influence of cathodic hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel are described. The results were discussed by taking into account hydrogen charged samples and without hydrogen. The corrosion resistance to pitting was qualified with the polarization curves. The conclusion is that, hydrogen deteriorated the passive film stability and corrosion resistance to pitting of 2205 duplex stainless steel. The presence of hydrogen in passive films increases corrosion current density and decreases the potential of the film breakdown. It was also found that degree of susceptibility to hydrogen action was dependent on the hydrogen charging conditions.

  9. Corrosion induced by cathodic hydrogen in 2205 duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Michalska, J, E-mail: joanna.k.michalska@polsl.pl [Department of Materials Science, Silesian University of Technology, Krasinskiego 8, 40-019 Katowice (Poland)

    2011-05-15

    In this work new results about the influence of cathodic hydrogen on passivity and corrosion resistance of 2205 duplex stainless steel are described. The results were discussed by taking into account hydrogen charged samples and without hydrogen. The corrosion resistance to pitting was qualified with the polarization curves. The conclusion is that, hydrogen deteriorated the passive film stability and corrosion resistance to pitting of 2205 duplex stainless steel. The presence of hydrogen in passive films increases corrosion current density and decreases the potential of the film breakdown. It was also found that degree of susceptibility to hydrogen action was dependent on the hydrogen charging conditions.

  10. Topographical Anisotropy and Wetting of Ground Stainless Steel Surfaces

    Directory of Open Access Journals (Sweden)

    Cornelia Bellmann

    2012-12-01

    Full Text Available Microscopic and physico-chemical methods were used for a comprehensive surface characterization of different mechanically modified stainless steel surfaces. The surfaces were analyzed using high-resolution confocal microscopy, resulting in detailed information about the topographic properties. In addition, static water contact angle measurements were carried out to characterize the surface heterogeneity of the samples. The effect of morphological anisotropy on water contact angle anisotropy was investigated. The correlation between topography and wetting was studied by means of a model of wetting proposed in the present work, that allows quantifying the air volume of the interface water drop-stainless steel surface.

  11. Deformation and rupture of stainless steel under cyclic, torsional creep

    OpenAIRE

    Rees, DWA

    2008-01-01

    Copyright 2008 @ Engineering Integrity Society. Recent results from a long-term, strain-limited, cyclic creep test program upon stainless steel tubes are given. The test conditions employed were: constant temperature 500 °C, shear stress Ƭ = ± 300 MPa and shear strain limits ƴ = ± 4%. It is believed that a cyclic creep behaviour for the material has been revealed that has not been reported before in the literature. That is, the creep curves for stainless steel under repeated, shear stress...

  12. Comparison of antibacterial ability of copper and stainless steel

    Institute of Scientific and Technical Information of China (English)

    GENG Ping; ZHANG Wen; TANG Hui; ZHANG Xinai; JIN Litong; FENG Zhen; WU Zirong

    2007-01-01

    In this paper,the electro-analysis and spectrophotometric analysis methods were used to study the antibacterial ability of copper and stainless steel materials.When Escherichia coli (E.coli) and photo-bacteria were used as samples,the antibacterial effect of stainless steel was very weak,while the percentage of bacteria dying from exposure to metallic copper for 30 min was over 90%.The antibacterial ability of copper has a potential application in the field of disinfection,food packaging and piping of drinking water.

  13. Development status of ultrasonic test techniques for cast stainless steel

    International Nuclear Information System (INIS)

    Ultrasonic testing has been thought to be difficult to apply to cast stainless steel which is used as the material for the main coolant pipes in pressurized water reactors (PWRs). An ultrasonic testing technique using large aperture twin crystal transducers was developed in INSS for application to inspection of the main coolant pipes. The method was evaluated in an application to detect circumferential and axial defects in the cast stainless steel pipes. It was found that (1) the defects could be detected which had a depth that was so small that their evaluation was not required; and (2) depth sizing and length sizing of detected defects were also possible. (author)

  14. Corrosion of 316L stainless steels MAVL wastes containers

    International Nuclear Information System (INIS)

    The long lived and medium activity wastes are conditioned or could be re-conditioned in primary drums of 316L stainless steels. In the framework of wastes storage, these drums will be placed in concrete containers; each containers would contain one or more drums. This document recalls global information on the corrosion of stainless steels, analyzes specific conditions bond to the drums conditioning in concrete containers and the nature of the wastes, and details the consequences on the possible risks of external and internal corrosion of the drums. (A.L.B.)

  15. Intergranular stress corrosion in soldered joints of stainless steel 304

    International Nuclear Information System (INIS)

    The intergranular stress cracking of welded joints of austenitic stainless steel, AISI 304, is a serious problem in BWR type reactors. It is associated with the simultaneous presence of three factors; stress, a critical media and sensibilization (DOS). EPR technique was used in order to verify the sensibilization degree in the base metal, and the zone affected by heat and welding material. The characterization of material was done. The objective of this work is the study of microstructure and the evaluation of EPR technique used for the determination of DOS in a welded plate of austenitic stainless steel AISI 304. (Author)

  16. Ozone decay on stainless steel and sugarcane bagasse surfaces

    Science.gov (United States)

    Souza-Corrêa, Jorge A.; Oliveira, Carlos; Amorim, Jayr

    2013-07-01

    Ozone was generated using dielectric barrier discharges at atmospheric pressure to treat sugarcane bagasse for bioethanol production. It was shown that interaction of ozone molecules with the pretreatment reactor wall (stainless steel) needs to be considered during bagasse oxidation in order to evaluate the pretreatment efficiency. The decomposition coefficients for ozone on both materials were determined to be (3.3 ± 0.2) × 10-8 for stainless steel and (2.0 ± 0.3) × 10-7 for bagasse. The results have indicated that ozone decomposition has occurred more efficiently on the biomass material.

  17. Evaluation of the thermal ageing of duplex stainless steels

    International Nuclear Information System (INIS)

    Three methods have been investigated to follow up the thermal ageing of duplex stainless steels: microhardness tests, instrumented ultramicrohardness tests and Small Angle Neutron Scattering (SANS) techniques. The values measured with these methods have been correlated with pertinent parameters of the metallurgical ageing phenomenon determined by Atom-Probe. These methods seem to be sensitive and reproducible enough to detect and follow up the ageing of duplex stainless steels. They can be applied on small samples (chips) drawn from in-service components. (authors). 10 refs., 9 figs., 3 tabs

  18. Application and development of stainless steel reinforced concrete structure

    Directory of Open Access Journals (Sweden)

    Meng Xian Hong

    2016-01-01

    Full Text Available Now reinforced concrete structure in our country develops very fast, and reinforced concrete structure has been widely applied by various buildings. But with the deepening of the research experts and scholars, they found in some areas where high corrosion of reinforced concrete structure with the increase of service time, the concrete cracks, and led to the internal steel bar corrosion conditions. In the face of these problems, the experts used stainless steel applied to the study of concrete. In this paper, the stainless stell reinforced concrete structure of the application and development status of made briefly.

  19. 78 FR 63517 - Control of Ferrite Content in Stainless Steel Weld Metal

    Science.gov (United States)

    2013-10-24

    ... COMMISSION Control of Ferrite Content in Stainless Steel Weld Metal AGENCY: Nuclear Regulatory Commission... revision to Regulatory Guide (RG) 1.31, ``Control of Ferrite Content in Stainless Steel Weld Metal.'' This... content in stainless steel weld metal. It updates the guide to remove references to outdated standards...

  20. 77 FR 60478 - Control of Ferrite Content in Stainless Steel Weld Metal

    Science.gov (United States)

    2012-10-03

    ... COMMISSION Control of Ferrite Content in Stainless Steel Weld Metal AGENCY: Nuclear Regulatory Commission... Ferrite Content in Stainless Steel Weld Metal.'' This guide describes a method that the NRC staff considers acceptable for controlling ferrite content in stainless steel weld metal. Revision 4 updates...

  1. Accelerated corrosion of stainless steel in thiocyanate-containing solutions

    Energy Technology Data Exchange (ETDEWEB)

    Pistorius, P Chris; Li, Wen

    2012-09-19

    It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, which is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the electrode impedance shows clearly that this pre-passivation is suppressed in the presence of thiocyanate. For the stainless steels, remarkable changes in the morphology of the corroded metal surface and in the surface concentration of chromium support the suggestion that pre-passivation of stainless steels is suppressed because dissolution of chromium is accelerated. Surface analysis confirmed that adsorbed sulfur / sulfide forms on the metal surfaces upon exposure to solutions containing thiocyanate or thiosulfate. For pure nickel, and steels containing nickel (and residual copper), bulk sulfide

  2. Properties of duplex stainless steels made by powder metallurgy

    Directory of Open Access Journals (Sweden)

    M. Rosso

    2007-04-01

    Full Text Available Purpose: of this paper was to examine the mechanical properties of duplex stainless steels.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies behind the preparation of mixes, Schaeffler’s diagram was taken into consideration. Prepared mixes have been sintered in a vacuum furnace with argon backfilling at 1260°C for 1 h. After sintering: rapid cooling have been applied in argon atmosphere. Produced duplex stainless steels have been studied by scanning and optical microscopy. Mechanical properties such as tensile strength, impact energy, hardness and wear rate were evaluated.Findings: According to achieved results, it was affirmed that applied sintering method as well as powder mixes preparation allows for manufacturing the sintered duplex steels with good mechanical properties which depends on austenite/ferrite ratio in the microstructure and elements partitioning between phases. The additions of alloying elements powders (promoting formation ferritic and austenitic phase to master alloy powder, makes possible the formation of structure and properties of sintered duplex stainless steels. Sintered duplex steels obtained starting from austenitic and ferritic powders with admixture of elemental powders achieve lower mechanical properties when compared to composition obtained by mixing ferritic and austenitic powder in equal amounts.Research limitations/implications: According to the powders characteristic, the applied fast cooling rate seems to be a good compromise for mechanical properties and microstructures, nevertheless further tests should be carried out in order to examine different cooling rates.Originality/value: The use of elemental powders added to a stainless steel base showed its potentialities, in terms of fair compressibility and final

  3. A review of hot cracking in austenitic stainless steel weldments

    International Nuclear Information System (INIS)

    The occurrence of hot cracking in austenitic stainless steel weldments is discussed with respect to its origin and metallurgical contributory factors. Of the three types of hot cracking, namely solidification cracking, liquation and ductility dip cracking, solidification cracking occurs in the interdendritic regions in weld metal while liquation and ductility dip cracking occur intergranularly in the heat-affected zone (HAZ). Segregation of impurity and minor elements such as sulphur, phosphorous, silicon, niobium, boron etc to form low melting eutectic phases has been found to be the major cause of hot cracking. Control of HAZ cracking requires minimisation of impurity elements in the base metal. In stabilized stainless steels containing niobium, higher amounts of delta-ferrite have been found necessary to prevent cracking than in unstabilized compositions. Titanium compounds have been found to cause liquation cracking in maraging steels and titanium containing stainless steels and superalloys. In nitrogen added stainless steels, cracking resistance decreases when the solidification mode changes to primary austenitic due to nitrogen addition. A review of the test methods to evaluate hot cracking behaviour showed that several external restraint and semi-self-restraint tests are available. The finger Test, WRC Fissure Bend Test, the PVR test and the Varestraint Test are described along with typical test results. Hot ductility testing to reveal HAZ cracking tendency during welding is described, which is of particular importance to stabilized stainless steels. Based on the literature, recommendations are made for welding stabilized and nitrogen added steels, indicating areas of further work. (author). 81 refs., 30 figs., 1 tab

  4. Characterization of microstructure and texture across dissimilar super duplex/austenitic stainless steel weldment joint by austenitic filler metal

    Energy Technology Data Exchange (ETDEWEB)

    Eghlimi, Abbas, E-mail: a.eghlimi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, Morteza [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Eskandarian, Masoomeh [Department of Materials Engineering, Shiraz University, Shiraz 71348-51154 (Iran, Islamic Republic of); Zabolian, Azam [Department of Natural Resources, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Szpunar, Jerzy A. [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 (Canada)

    2015-08-15

    The evolution of microstructure and texture across an as-welded dissimilar UNS S32750 super duplex/UNS S30403 austenitic stainless steel joint welded by UNS S30986 (AWS A5.9 ER309LMo) austenitic stainless steel filler metal using gas tungsten arc welding process was evaluated by optical micrography and EBSD techniques. Due to their fabrication through rolling process, both parent metals had texture components resulted from deformation and recrystallization. The weld metal showed the highest amount of residual strain and had large austenite grain colonies of similar orientations with little amounts of skeletal ferrite, both oriented preferentially in the < 001 > direction with cub-on-cube orientation relationship. While the super duplex stainless steel's heat affected zone contained higher ferrite than its parent metal, an excessive grain growth was observed at the austenitic stainless steel's counterpart. At both heat affected zones, austenite underwent some recrystallization and formed twin boundaries which led to an increase in the fraction of high angle boundaries as compared with the respective base metals. These regions showed the least amount of residual strain and highest amount of recrystallized austenite grains. Due to the static recrystallization, the fraction of low degree of fit (Σ) coincident site lattice boundaries, especially Σ3 boundaries, was increased in the austenitic stainless steel heat affected zone, while the formation of subgrains in the ferrite phase increased the content of < 5° low angle boundaries at that of the super duplex stainless steel. - Graphical abstract: Display Omitted - Highlights: • Extensive grain growth in the HAZ of austenitic stainless steel was observed. • Intensification of < 100 > orientated grains was observed adjacent to both fusion lines. • Annealing twins with Σ3 CSL boundaries were formed in the austenite of both HAZ. • Cub-on-cube OR was observed between austenite and ferrite in the weld

  5. Corrosion resistance of stainless steel pipes in soil

    Energy Technology Data Exchange (ETDEWEB)

    Sjoegren, L.; Camitz, G. [Swerea KIMAB AB, Box 55970, SE-102 16 Stockholm (Sweden); Peultier, J.; Jacques, S.; Baudu, V.; Barrau, F.; Chareyre, B. [Industeel and ArcelorMittal R and D, 56 rue Clemenceau, BP19, FR-71201 le Creusot, Cedex (France); Bergquist, A. [Outokumpu Stainless AB, P.O. Box 74, SE-774 22 Avesta (Sweden); Pourbaix, A.; Carpentiers, P. [Belgian Centre for Corrosion Study, Avenue des Petits-Champs 4A, BE 1410 Waterloo (Belgium)

    2011-04-15

    To be able to give safe recommendations concerning the choice of suitable stainless steel grades for pipelines to be buried in various soil environments, a large research programme, including field exposures of test specimens buried in soil in Sweden and in France, has been performed. Resistance against external corrosion of austenitic, super austenitic, lean duplex, duplex and super duplex steel grades in soil has been investigated by laboratory tests and field exposures. The grades included have been screened according to their critical pitting-corrosion temperature and according to their time-to-re-passivation after the passive layer has been destroyed locally by scratching. The field exposures programme, being the core of the investigation, uses large specimens: 2 m pipes and plates, of different grades. The exposure has been performed to reveal effects of aeration cells, deposits or confined areas, welds and burial depth. Additionally, investigations of the tendency of stainless steel to corrode under the influence of alternating current (AC) have been performed, both in the laboratory and in the field. Recommendations for use of stainless steels under different soil conditions are given based on experimental results and on operating experiences of existing stainless steel pipelines in soil. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Electrochemically induced annealing of stainless-steel surfaces

    Science.gov (United States)

    Burstein, G. T.; Hutchings, I. M.; Sasaki, K.

    2000-10-01

    Modification of the surface properties of metals without affecting their bulk properties is of technological interest in demanding applications where surface stability and hardness are important. When austenitic stainless steel is heavily plastically deformed by grinding or rolling, a martensitic phase transformation occurs that causes significant changes in the bulk and surface mechanical properties of the alloy. This martensitic phase can also be generated in stainless-steel surfaces by cathodic charging, as a consequence of lattice strain generated by absorbed hydrogen. Heat treatment of the steel to temperatures of several hundred degrees can result in loss of the martensitic structure, but this alters the bulk properties of the alloy. Here we show that martensitic structures in stainless steel can be removed by appropriate electrochemical treatment in aqueous solutions at much lower temperature than conventional annealing treatments. This electrochemically induced annealing process allows the hardness of cold-worked stainless steels to be maintained, while eliminating the brittle martensitic phase from the surface. Using this approach, we are able to anneal the surface and near-surface regions of specimens that contain rolling-induced martensite throughout their bulk, as well as those containing surface martensite induced by grinding. Although the origin of the electrochemical annealing process still needs further clarification, we expect that this treatment will lead to further development in enhancing the surface properties of metals.

  7. Low Temperature Surface Carburization of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K

    2007-12-07

    Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys

  8. Carburisation of stainless steel caused by oil in sodium

    International Nuclear Information System (INIS)

    The primary objectives of this work were to investigate the kinetics of austenitic stainless steel carburisation in sodium caused by oil in sodium, and to measure the corresponding 'sodium carbon activity' (a quantitative measure of sodium steel carburisation potential). For comparative purposes, the steel carburising effects of chemically simpler carbon sources have also been studied. The specific experimental investigations have involved: (i) A study of the kinetics of stainless steel carburisation at 5500C caused by oil in sodium; (ii) A determination of the effective steel carburisation potential (carbon activity) arising from oil ingress, and its persistence with time, and (iii) A comparison of oil and chemically simpler carbon sources, namely graphite and cementite (as carburised iron, Fe-Fe3C), with regard to both kinetics of steel carburisation and sodium carbon activities produced. In all cases, the nature and extent of carburisation has been determined by optical metallography, X-ray and nuclear microprobe analysis. Preliminary studies on the mutual effect of steel surfaces in close proximity have also been conducted. Previous studies on steel carburisation in sodium are outlined, and the present results are discussed in the context of available thermodynamic and kinetic data pertaining to the carbon-steel and carbon-sodium systems. (author)

  9. Cold Cracking of Flux Cored Arc Welded Armour Grade High Strength Steel Weldments

    Institute of Scientific and Technical Information of China (English)

    G.Magudeeswaran; V.Balasubramanian; G.Madhusudhan Reddy

    2009-01-01

    In this investigation, an attempt has been made to study the influence of welding consumables on the factors that influence cold cracking of armour grade quenched and tempered (Q&T) steel welds. Flux cored arc welding (FCAW) process were used making welds using austenitic stainless steel (ASS) and low hydrogen ferritic steel (LHF) consumables. The diffusible hydrogen levels in the weld metal of the ASS and LHF consumables were determined by mercury method. Residual stresses were evaluated using X-ray stress analyzer and implant test was carried out to study the cold cracking of the welds. Results indicate that ASS welds offer a greater resistance to cold cracking of armour grade Q&T steel welds.

  10. Sealing of thermally-sprayed stainless steel coatings against corrosion using nickel electroplating technique

    Directory of Open Access Journals (Sweden)

    Hathaipat Koiprasert

    2007-07-01

    Full Text Available Electric arc spraying (EAS is one of the thermal spray techniques used for restoration and to providecorrosion resistance. It can be utilized to build up coatings to thicknesses of several millimeters, It is easy to use on-site. Most importantly, the cost of this technique is lower than other thermal spraying techniques thatmay be suitable for part restoration. A major disadvantage associated with the electric arc sprayed coating is its high porosity, which can be as high as 3-8% making it not appropriate for use in immersion condition. This work was carried out around the idea of using electroplating to seal off the pore of the EAS coating, with an aim to improve the corrosion resistance of the coating in immersion condition. This research compared the corrosion behavior of a stainless steel 316 electric arc sprayed coating in 2M NaOH solution at 25oC. It was found that the Ni plating used as sealant can improve the corrosion resistance of the EAS coating. Furthermore, the smoothened and plated stainless steel 316 coating has a better corrosion resistance than the plated EAS coating that was not ground to smoothen the surface before plating.

  11. Process-microstructure-corrosion interrelations for stainless steel

    OpenAIRE

    Lindell, David

    2015-01-01

    Stainless steels were first developed in the early 20th century and have since then emerged as a very diverse class of engineering materials. Along with steels having new combinations of properties, there is a continuous development of new technologies allowing the material to be produced in a faster and more energy effcient manner. A prerequisite for new technologies to be adapted quicklyis a fundamental understanding of the microstructure evolution throughout theprocess chain. The first par...

  12. High density sintered stainless steels with improved properties

    OpenAIRE

    M. Actis Grande; M. Rosso

    2007-01-01

    Purpose: of this paper is the study of the properties of sintered AISI 316L (1.4404 according to EN 10088. Sintered stainless steels occupy a prominent position in the high alloyed steels, however their properties are limited by the presence of porosity. The improvement of quality and performances of products coupled with a reduction of manufacturing costs calls for high compacting pressures, as well as high sintering temperatures. However, the possibility to fill the open porosity of sintere...

  13. Hydrometallurgical removal of zinc from stainless steel flue dusts

    OpenAIRE

    Järvinen, Outi

    2013-01-01

    Stainless steel flue dusts are problematic to the steel industry because of their chemi-cal composition that makes direct recycling and landfilling impossible. Pyrometallur-gical and hydrometallurgical processes have been tested in dust treatment. At the moment, most of the processes that have reached commercialization have been py-rometallurgical. Still, it is thought that hydrometallurgy could offer solutions espe-cially in small scale on-site treatment as it is less energy intensive and re...

  14. Construction of a stainless steel storage tank for phosphoric acid

    OpenAIRE

    Buh, Igor

    2006-01-01

    The main purpose of this thesis was to get acquainted with all necessary procedures for steel storage tank manufacturing and assembly control. The representative storage tank was built from stainless steel and it was designed to hold 750 m3 of phosphoric acid. In the first section all legally mandatory control procedures are described and they are applied to our storage tank in the second section. Welding control is presented, which consists of destructive and non-destructive inspections of t...

  15. Stainless steel weld metal designed to mitigate residual stresses

    OpenAIRE

    Shirzadi, A. A.; Bhadeshia, H. K. D. H.; Karlsson, L.; Withers, P.J.

    2009-01-01

    There have been considerable efforts to create welding consumables which on solid state phase transformation partly compensate for the stresses which develop when a constrained weld cools to ambient temperatures. All of these efforts have focused on structural steels which are ferritic. In the present work, alloy design methods have been used to create a stainless steel welding consumable which solidifies as δ ferrite, transforms almost entirely into austenite which then undergoes martensitic...

  16. Instrumental Neuron Activation Analysis for certification of stainless steel materials

    International Nuclear Information System (INIS)

    The use of Instrumental Neuron Activation Analysis (INAA) may contribute to improve the certification of the materials, especially in the case of minor and trace elements. In presented paper the INAA method of analysis of stainless steel materials has been elaborated. The obtained results were compared with those of common analytical techniques. The presented results show the usefulness of the INAA method for the certification of CRMs for the iron and steel industry

  17. Mechanical properties of low-nickel stainless steel

    Science.gov (United States)

    Montano, J. W.

    1978-01-01

    Demand for improved corrosion-resistant steels, coupled with increased emphasis on conserving strategic metals, has led to development of family of stainless steels in which manganese and nitrogen are substituted for portion of usual nickel content. Advantages are approximately-doubled yield strength in annealed condition, better resistance to stress-corrosion cracking, retention of low magnetic permeability even after severe cold working, excellent strength and ductility at cryogenic temperatures, superior resistance to wear and galling, and excellent high-temperature properties.

  18. Properties of super stainless steels for orthodontic applications.

    Science.gov (United States)

    Oh, Keun-Taek; Kim, Young-Sik; Park, Yong-Soo; Kim, Kyoung-Nam

    2004-05-15

    Orthodontic stainless-steel appliances are considered to be corrosion resistant, but localized corrosion can occur in the oral cavity. This study was undertaken to evaluate the properties of super stainless steels in orthodontic applications. Accordingly, the metallurgical properties, mechanical properties, corrosion resistance, amount of the released nickel, cytotoxicity, and characteristics of the passive film were investigated. Corrosion resistances of the specimens were high and in the following order: super austenitic stainless steel (SR-50A) > super ferritic stainless steel (SFSS) = super duplex stainless steel (SR-6DX) > 316L SS > super martensitic stainless steel (SR-3Mo) in artificial saliva, 37 degrees C. At 500 mV (SCE), current densities of SR-50A, SFSS, SR-6DX, 316L SS, and SR-3Mo were 5.96 microA/cm(2), 20.3 microA/cm(2), 31.9 microA/cm(2), 805 microA/cm(2), and 5.36 mA/cm(2), respectively. Open circuit potentials of SR-50A, 316L SS, SR-6DX, SR-3Mo, and SFSS were - 0.2, - 0.22, - 0.24, - 0.43, and - 0.46 V (SCE), respectively. SR-50A, SFSS, and SR-6DX released below 3 ng/ml nickel for 8 weeks, and increased a little with immersion time, and 316L SS released about 3.5 ng/ml nickel, but SR-3Mo released a large amount of nickel, which increased with immersion time. The study demonstrated that SR-50A, SR-6DX, and SFSS have high corrosion resistance and mild or no cytotoxicity, due to the passive film enhanced by synergistic effect of Mo + N or by high addition effect of Cr + W. All super stainless steels showed very low cytotoxicity regardless of their nickel contents, although SR-3Mo was found to be relatively cytotoxic. From these studies, these steels are considered suitable for orthodontic applications. PMID:15116408

  19. Adhesion of food-borne bacteria to stainless steel is reduced by food conditioning films

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yin; Jorgensen, R.L.;

    2009-01-01

    to stainless steel. Attachment of Pseudomonas fluorescens AH2 to stainless steel coated with water-soluble coatings of animal origin was significantly reduced as compared with noncoated stainless steel or stainless steel coated with laboratory substrate or extracts of plant origin. Coating with animal extracts...... also decreases adhesion of other food-relevant bacteria. The manipulation of adhesion was not attributable to growth inhibitory effects. Chemical analysis revealed that the stainless steels were covered by homogenous layers of adsorbed proteins. The presence of tropomyocin was indicated by appearance...

  20. Effect of ultrafine grain on tensile behaviour and corrosion resistance of the duplex stainless steel.

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Limin, Dong

    2016-05-01

    The ultrafine grained 2205 duplex stainless steel was obtained by cold rolling and annealing. The tensile properties were investigated at room temperature. Comparing with coarse grained stainless steel, ultrafine grained sample showed higher strength and plasticity. In addition, grain size changed deformation orientation. The strain induced α'-martensite was observed in coarse grained 2205 duplex stainless steel with large strain. However, the grain refinement inhibited the transformation of α'-martensite;nevertheless, more deformation twins improved the strength and plasticity of ultrafine grained 2205 duplex stainless steel. In addition, the grain refinement improved corrosion resistance of the 2205 duplex stainless steel in sodium chloride solution. PMID:26952459

  1. Ionic bombardment of stainless steel by nitrogen and nickel ions immersion

    Institute of Scientific and Technical Information of China (English)

    XIONG Ling; HU Yong-jun; XU jian; MENG Ji-long

    2008-01-01

    A new nitriding process was used to carry out the ionic bombardment, in which nickel ion was introduced. The microstructure, composition and properties of the treated stainless steel were studied by means of scanning electron microscopy(SEM), micro-hardness test and electrochemistry method. The results show that the hardness of the stainless steel is greatly increased after ionic bombardment under nitrogen and nickel ions immersion. Vickers' hardness as high as Hv1268 is obtained. The bombarded stainless steel is of a little reduction in corrosion resistance, as compared with the original stainless steel. However, as compared with the traditional ion-nitriding stainless steel, the corrosion resistance is greatly improved.

  2. Effect of ultrafine grain on tensile behaviour and corrosion resistance of the duplex stainless steel.

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Limin, Dong

    2016-05-01

    The ultrafine grained 2205 duplex stainless steel was obtained by cold rolling and annealing. The tensile properties were investigated at room temperature. Comparing with coarse grained stainless steel, ultrafine grained sample showed higher strength and plasticity. In addition, grain size changed deformation orientation. The strain induced α'-martensite was observed in coarse grained 2205 duplex stainless steel with large strain. However, the grain refinement inhibited the transformation of α'-martensite;nevertheless, more deformation twins improved the strength and plasticity of ultrafine grained 2205 duplex stainless steel. In addition, the grain refinement improved corrosion resistance of the 2205 duplex stainless steel in sodium chloride solution.

  3. Redemption of asthma pharmaceuticals among stainless steel and mild steel welders

    DEFF Research Database (Denmark)

    Kristiansen, Pernille; Jørgensen, Kristian Tore; Hansen, Johnni;

    2015-01-01

    PURPOSE: The purpose was to examine bronchial asthma according to cumulative exposure to fume particulates conferred by stainless steel and mild steel welding through a proxy of redeemed prescribed asthma pharmaceuticals. METHODS: A Danish national company-based historical cohort of 5,303 male ever...... was estimated by combining questionnaire data on welding work with a welding exposure matrix. The estimated exposure accounted for calendar time, welding intermittence, type of steel, welding methods, local exhaustion and welding in confined spaces. Hazard ratios (HRs) with 95 % confidence intervals (CIs) were...... nonsignificant increased rate of redemption of asthma medicine was observed among high-level exposed stainless steel welders in comparison with low-level exposed welders (HR 1.54, 95 % CI 0.76-3.13). This risk increase was driven by an increase risk among non-smoking stainless steel welders (HR 1.46, 95 % CI 1...

  4. Effect of pulsating water jet peening on stainless steel

    OpenAIRE

    Hlaváček, Petr

    2015-01-01

    Effects of action of pulsating water jet on polished surface of the stainless steel AISI 316L are presented. Surface slip bands appeared after this treatment. In the most severe conditions, microcracks were formed. Hardness measurement showed that the affected layer was thinner than 60 μm. Application of the pulsating water jet has beneficial effect on the fatigue life of the material.

  5. Fatigue behavior of welded austenitic stainless steel in different environments

    Directory of Open Access Journals (Sweden)

    D.S. Yawas

    2014-01-01

    Full Text Available The fatigue behavior of welded austenitic stainless steel in 0.5 M hydrochloric acid and wet steam corrosive media has been investigated. The immersion time in the corrosive media was 30 days to simulate the effect on stainless steel structures/equipment in offshore and food processing applications and thereafter annealing heat treatment was carried out on the samples. The findings from the fatigue tests show that seawater specimens have a lower fatigue stress of 0.5 × 10−5 N/mm2 for the heat treated sample and 0.1 × 10−5 N/mm2 for the unheat-treated sample compared to the corresponding hydrochloric acid and steam samples. The post-welding heat treatment was found to increase the mechanical properties of the austenitic stainless steel especially tensile strength but it reduces the transformation and thermal stresses of the samples. These findings were further corroborated by the microstructural examination of the stainless steel specimen.

  6. Failure Assessment Diagram for Brazed 304 Stainless Steel Joints

    Science.gov (United States)

    Flom, Yory

    2011-01-01

    Interaction equations were proposed earlier to predict failure in Albemet 162 brazed joints. Present study demonstrates that the same interaction equations can be used for lower bound estimate of the failure criterion in 304 stainless steel joints brazed with silver-based filler metals as well as for construction of the Failure Assessment Diagrams (FAD).

  7. Sticking Phenomenon Occurring during Hot Rolling of Ferritic Stainless Steels

    International Nuclear Information System (INIS)

    Sticking phenomenon occurring during hot rolling of two ferritic stainless steels, STS 430J1L and STS 436L, was investigated in this study. A hot rolling simulation test was carried out using a high-temperature wear tester capable of controlling rolling speed, load, and temperature. The simulation test results at 900 .deg. C and 1000 .deg. C revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation, for the both stainless steels, and that STS 430J1L had a smaller number of sticking nucleation sites than the STS436L because of higher high-temperature hardness, thereby leading to a smaller amount of the sticking. When the test temperature was 1070 .deg. C, the sticking hardly occurred in both stainless steels as Fe-Cr oxide layers were formed on the surface of the rolled materials. These findings suggested that the improvement of high-temperature properties of stainless steels and the appropriate rolling conditions for readily forming oxide layers on the rolled material surface were required in order to prevent or minimize the sticking

  8. Hydrogen embrittlement of super duplex stainless steel in acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Elhoud, A.M.; Renton, N.C.; Deans, W.F. [University of Aberdeen, School of Engineering, Aberdeen, AB24 3UE (United Kingdom)

    2010-06-15

    Super duplex stainless steel (SDSS) is a good choice of material when resistance to harsh environments is needed. Despite the material's excellent corrosion resistance and high strength, a number of in-service failures have been recorded. The root cause of these failures was environmentally induced cracking initiated at manufacturing and in-service metallurgical defects. In this study the hydrogen embrittlement of pre-strained super duplex stainless steel specimens was investigated after 48 h cathodic charging in 0.1 M H{sub 2}SO{sub 4}. The metallurgical changes that resulted from four levels of cold work (4, 8, 12, and 16% plastic strain) were considered and their effect on the embrittlement of the SDSS alloy was investigated. After hydrogen charging, the specimens were pulled immediately to failure and the mechanical properties evaluated. The obtaining fracture morphology was investigated using low and high magnification microscopy. Experimental results indicated that charging the super duplex stainless steel alloy with hydrogen caused varying degrees of embrittlement depending on cold work level. Increasing cold work resulted in a reduction of the elongation to failure. Microscopic investigation confirmed the significant effect of cold work on the hydrogen embrittlement susceptibility of the super duplex stainless steel alloy investigated. (author)

  9. Resistance microwelding of 316L stainless steel wire to block

    DEFF Research Database (Denmark)

    Friis, Kasper Storgaard; Khan, M.I.; Bay, Niels;

    2011-01-01

    The excellent corrosion resistance of low carbon vacuum melted 316 stainless steel coupled with its non-magnetic properties makes it ideal for biomedical applications. The typical joint geometry for microcomponents, such as medical implants, includes joining of fine wire to a larger block. However...

  10. 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 presen...

  11. Solidification cracking in austenitic stainless steel welds

    Indian Academy of Sciences (India)

    V Shankar; T P S Gill; S L Mannan; S Sundaresan

    2003-06-01

    Solidification cracking is a significant problem during the welding of austenitic stainless steels, particularly in fully austenitic and stabilized compositions. Hot cracking in stainless steel welds is caused by low-melting eutectics containing impurities such as S, P and alloy elements such as Ti, Nb. The WRC-92 diagram can be used as a general guide to maintain a desirable solidification mode during welding. Nitrogen has complex effects on weld-metal microstructure and cracking. In stabilized stainless steels, Ti and Nb react with S, N and C to form low-melting eutectics. Nitrogen picked up during welding significantly enhances cracking, which is reduced by minimizing the ratio of Ti or Nb to that of C and N present. The metallurgical propensity to solidification cracking is determined by elemental segregation, which manifests itself as a brittleness temperature range or BTR, that can be determined using the varestraint test. Total crack length (TCL), used extensively in hot cracking assessment, exhibits greater variability due to extraneous factors as compared to BTR. In austenitic stainless steels, segregation plays an overwhelming role in determining cracking susceptibility.

  12. 77 FR 1504 - Stainless Steel Wire Rod From India

    Science.gov (United States)

    2012-01-10

    ... Commission instituted this review on July 1, 2011 (76 FR 38686) and determined on October 4, 2011, that it would conduct an expedited review (76 FR 64105, October 17, 2011). The Commission transmitted its... COMMISSION Stainless Steel Wire Rod From India Determination On the basis of the record \\1\\ developed in...

  13. Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

    Science.gov (United States)

    Lewis, Pattie L.; Kolody, Mark; Curran, Jerry

    2013-01-01

    Corrosion is an extensive problem that affects the Department of Defense (DoD) and National Aeronautics and Space Administration (NASA). The deleterious effects of corrosion result in steep costs, asset downtime affecting mission readiness, and safety risks to personnel. Consequently, it is vital to reduce corrosion costs and risks in a sustainable manner. The DoD and NASA have numerous structures and equipment that are fabricated from stainless steel. The standard practice for protection of stainless steel is a process called passivation. Typical passivation procedures call for the use of nitric acid; however, there are a number of environmental, worker safety, and operational issues associated with its use. Citric acid offers a variety of benefits including increased safety for personnel, reduced environmental impact, and reduced operational cost. DoD and NASA agreed to collaborate to validate citric acid as an acceptable passivating agent for stainless steel. This paper details our investigation of prior work developing the citric acid passivation process, development of the test plan, optimization of the process for specific stainless steel alloys, ongoing and planned testing to elucidate the process' resistance to corrosion in comparison to nitric acid, and preliminary results.

  14. Elaboration of selective solar energy absorbers beginning with stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Aries, L.; Bonino, J.P.; Benavente, R.; Laaouini, A.; Traverse, J.P.

    1981-01-01

    An original simple and cheap method of elaboration of selective surfaces is described. The method involves anodic oxydation of stainless steel in acid solution with addition of sulfides; chemical conversion of the metallic surface is achieved. The selective surfaces exhibit an excellent thermal stability.

  15. Metal release from stainless steel in biological environments: A review.

    Science.gov (United States)

    Hedberg, Yolanda S; Odnevall Wallinder, Inger

    2016-03-01

    Due to its beneficial corrosion resistance, stainless steel is widely used in, e.g., biomedical applications, as surfaces in food contact, and for products intended to come into skin contact. Low levels of metals can be released from the stainless steel surface into solution, even for these highly corrosion resistant alloys. This needs to be considered in risk assessment and management. This review aims to compile the different metal release mechanisms that are relevant for stainless steel when used in different biological settings. These mechanisms include corrosion-induced metal release, dissolution of the surface oxide, friction-induced metal release, and their combinations. The influence of important physicochemical surface properties, different organic species and proteins in solution, and of biofilm formation on corrosion-induced metal release is discussed. Chemical and electrochemical dissolution mechanisms of the surface oxides of stainless steel are presented with a focus on protonation, complexation/ligand-induced dissolution, and reductive dissolution by applying a perspective on surface adsorption of complexing or reducing ligands and proteins. The influence of alloy composition, microstructure, route of manufacture, and surface finish on the metal release process is furthermore discussed as well as the chemical speciation of released metals. Typical metal release patterns are summarized. PMID:26514345

  16. Transformation in Austenitic Stainless Steel Sheet under Different Loading Directions

    NARCIS (Netherlands)

    Boogaard, van den A.H.; Krauer, J.; Hora, P.

    2011-01-01

    The stress-strain relation for austenitic stainless steels is based on 2 main contributions: work hardening and a phase transformation from austenite to martensite. The transformation is highly temperature dependent. In most models for phase transformation from austenite to martensite, the stress tr

  17. Heat treatment method for two-phase stainless steel

    International Nuclear Information System (INIS)

    A two-phase stainless steel the toughness of which is reduced by exposure to a high temperature is kept at from 900degC to 1040degC to be solidified and then quenched. With such procedures, a δ-phase deposited in a ferrite phase can be eliminated to restore the toughness. In the solidification step, the two-phase stainless steel having a plate thickness of 1cm or less is kept for 15mins or more, and is kept for additional 5min on every increase of the thickness of 1cm, and then it is compulsorily cooled with water or air. In the heat treatment comprising such steps, a Cr-depleted layer of the welded portion of the two-phase stainless steel of reduced toughness is eliminated to restore an initial state thereby enabling to maintain the integrity of the welded portion. Since the δ-phase deposited in the ferrite phase can be eliminated by solid-solubilizing the two phase stainless steel of reduced toughness by induction heating, reduced toughness can be restored thereby enabling to keep the integrity. (T.M.)

  18. Towards commercialization of fast gaseous nitrocarburising stainless steel

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    A novel method for fast and versatile low temperature nitrocarburising of stainless steel has recently been invented by the present authors. Selected results obtained with this new surface hardening process are presented. It is shown that it is possible to obtain a case thickness of 20 μm on...

  19. Sticking Phenomenon Occurring during Hot Rolling of Ferritic Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Son, Chang Young; Kim, Chang Kyu; Ha, Dae Jin; Lee, Sung Hak [Pohang Univ. of Institute of Science and Technology, Pohang (Korea, Republic of); Lee, Jong Seog; Kim, Kwang Tae; Lee, Yong Deuk [POSCO Technical Research Lab., Gwangyang (Korea, Republic of)

    2007-01-15

    Sticking phenomenon occurring during hot rolling of two ferritic stainless steels, STS 430J1L and STS 436L, was investigated in this study. A hot rolling simulation test was carried out using a high-temperature wear tester capable of controlling rolling speed, load, and temperature. The simulation test results at 900 .deg. C and 1000 .deg. C revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation, for the both stainless steels, and that STS 430J1L had a smaller number of sticking nucleation sites than the STS436L because of higher high-temperature hardness, thereby leading to a smaller amount of the sticking. When the test temperature was 1070 .deg. C, the sticking hardly occurred in both stainless steels as Fe-Cr oxide layers were formed on the surface of the rolled materials. These findings suggested that the improvement of high-temperature properties of stainless steels and the appropriate rolling conditions for readily forming oxide layers on the rolled material surface were required in order to prevent or minimize the sticking.

  20. Repair welding of cracked steam turbine blades using austenitic and martensitic stainless-steel consumables

    International Nuclear Information System (INIS)

    The procedure for repair welding of cracked steam turbine blades made of martensitic stainless steels has been developed using the gas tungsten arc welding process. Weld repair procedures were developed using both ER 316L austenitic and ER 410 martensitic stainless-steel filler wire. The overall development of the repair welding procedure included selection of welding consumables (for austenitic filler metal), optimisation of post-weld heat treatment parameters, selection of suitable method for local pre-heating and post-weld heat treatment (PWHT) of the blades, determination of mechanical properties of weldments in as-welded and PWHT conditions, and microsturctural examination. After various trials using different procedures, the procedure of local PWHT (and preheating when using martensitic stainless-steel filler wire) using electrical resistance heating on the top surface of the weldment and monitoring the temperature by placing a thermocouple at the bottom of the weld was found to give the most satisfactory results. These procedures have been developed and/or applied for repair welding of cracked blades in steam turbines

  1. Repair welding of cracked steam turbine blades using austenitic and martensitic stainless-steel consumables

    Energy Technology Data Exchange (ETDEWEB)

    Bhaduri, A.K. E-mail: bhaduri@igcar.ernet.in; Gill, T.P.S.; Albert, S.K.; Shanmugam, K.; Iyer, D.R

    2001-06-01

    The procedure for repair welding of cracked steam turbine blades made of martensitic stainless steels has been developed using the gas tungsten arc welding process. Weld repair procedures were developed using both ER 316L austenitic and ER 410 martensitic stainless-steel filler wire. The overall development of the repair welding procedure included selection of welding consumables (for austenitic filler metal), optimisation of post-weld heat treatment parameters, selection of suitable method for local pre-heating and post-weld heat treatment (PWHT) of the blades, determination of mechanical properties of weldments in as-welded and PWHT conditions, and microsturctural examination. After various trials using different procedures, the procedure of local PWHT (and preheating when using martensitic stainless-steel filler wire) using electrical resistance heating on the top surface of the weldment and monitoring the temperature by placing a thermocouple at the bottom of the weld was found to give the most satisfactory results. These procedures have been developed and/or applied for repair welding of cracked blades in steam turbines.

  2. Numerical modelling of steel arc welding

    International Nuclear Information System (INIS)

    Welding is a highly used assembly technique. Welding simulation software would give access to residual stresses and information about the weld's microstructure, in order to evaluate the mechanical resistance of a weld. It would also permit to evaluate the process feasibility when complex geometrical components are to be made, and to optimize the welding sequences in order to minimize defects. This work deals with the numerical modelling of arc welding process of steels. After describing the industrial context and the state of art, the models implemented in TransWeld (software developed at CEMEF) are presented. The set of macroscopic equations is followed by a discussion on their numerical implementation. Then, the theory of re-meshing and our adaptive anisotropic re-meshing strategy are explained. Two welding metal addition techniques are investigated and are compared in terms of the joint size and transient temperature and stresses. The accuracy of the finite element model is evaluated based on experimental results and the results of the analytical solution. Comparative analysis between experimental and numerical results allows the assessment of the ability of the numerical code to predict the thermomechanical and metallurgical response of the welded structure. The models limitations and the phenomena identified during this study are finally discussed and permit to define interesting orientations for future developments. (author)

  3. Welding Characteristics of Nitrogen Added Stainless Steels for Nuclear Application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y. D. [Pohang Iron and Steel Co., Ltd, Pohang (Korea, Republic of)

    1997-07-01

    Characteristics of properties and manufacturing process was evaluated in development of high strength and corrosion resistant stainless steel. The continuous cast structure of STS 316L was similar to that of STS 304. The most of residual {delta}-ferrite of STS 316L was vermicular type. The residual {delta}-ferrite content increased from the surface towards the center of the slab and after reaching a maximum value at about 50mm distance from surface and steeply decreased towards the center itself. Hot ductility of STS 304L and STS 316L stainless steels containing below 1000 ppm N was appeared to be reasonably good in the range of hot rolling temperature. In case of the steels containing over 1000 ppm N, the hot ductility was decreased rapidly when sulfur content of the steel was above 20 ppm. Therefore, to achieve good hot ductility of the high nitrogen containing steel, reduction of sulfur contents is required as low as possible. The inter granular corrosion resistance and impact toughness of STS 316L were increased with increasing the nitrogen contents. Yield strength and tensile strength of 304 and 316 stainless steels are increased linearly with increasing the nitrogen contents but their elongations are decreased with increasing the nitrogen contents. Therefore, the mechanical properties of these stainless steels could be controlled with variation of nitrogen. The effects of nitrogen on the resistance of stress corrosion cracking (SCC) can be explained by improvement of the load bearing capacity with increasing tensile strength rather than inhibition of trans granular SCC crack generation and propagation. 101 refs., 17 tabs., 105 figs. (author)

  4. Phase formation at bonded vanadium and stainless steel interfaces

    International Nuclear Information System (INIS)

    The interface between vanadium bonded to stainless steel was studies to determine whether a brittle phase formed during three joining operations. Inertia friction welds between V and 21-6-9 stainless steel were examined using TEM. In the as-welded condition, a continuous, polygranular intermetallic layer about 0.25 μm thick was present at the interface. This layer grew to about 50 μm thick during heat treatment at 1000 degrees C for two hours. Analysis of electron diffraction patterns confirmed that this intermetallic was the ω phase. The interface between vanadium and type 304, SANDVIK SAF 2205, and 21-6-9 stainless steel bonded by a co-extrusion process had intermetallic particles at the interface in the as-extruded condition. Heat treatment at 1000 degrees C for two hours caused these particles to grow into continuous layers in all three cases. Based on the appearance, composition and hardness of this interfacial intermetallic, it was also concluded to be ω phase. Bonding V to type 430 stainless steel by co-extrusion caused V-rich carbides to form at the interface due to the higher concentration of C in the type 430 than in the other stainless steels investigated. The carbide particles initially present grew into a continuous layer during a two-hour heat treatment at 1000 degrees C. Co-hipping 21-6-9 stainless steel tubing with V rod resulted in slightly more concentric specimens than the co-extruded ones, but a continuous layer of the ω phase formed during the hipping operation. This brittle layer could initiate failure during subsequent forming operations. The vanadium near the stainless steel interface in the co-extruded and co-hipped tubing in some cases was harder than before heat treatment. It was concluded that this hardening was due to thermal straining during cooling following heat treatment and that thermal strains might present a greater problem than seen here when longer tubes are used in actual applications

  5. Behaviour of cold-formed stainless steel beams at elevated temperatures

    Institute of Scientific and Technical Information of China (English)

    Ju CHEN; Wei-liang JIN

    2008-01-01

    A study of the behaviour of constructional cold-formed stainless steel beams at elevated temperatures was conducted in this paper.An accurate finite element model(FEM)for stainless steel beams was developed using the finite element program ABAQUS.Stainless steel beams having different cross-sections were simulated in this study.The nonlinear FEM was verified against the experimental results.Generally,the developed FEM could accurately simulate the stainless steel beams.Based on the high temperature stainless steel material test results,a parametric study was carried out on stainless steel beams at elevated tem-peratures using the verified FEM.Both high strength stainless steel EN 1.4462 and normal strength stainless steel EN 1.4301 were considered.A total of 42 stainless steel beams were simulated in the parametric study.The effect of temperatures on the behaviour of stainless steel beams was investigated.In addition,a limiting temperature for stainless steel beams was also proposed.

  6. Low temperature surface hardening of stainless steel; the role of plastic deformation

    DEFF Research Database (Denmark)

    Bottoli, Federico; Jespersen, Freja Nygaard; Hattel, Jesper Henri;

    2016-01-01

    Thermochemical surface engineering by nitriding of austenitic stainless steel transforms the surface zone into expanded austenite, which improves the wear resistance of the stainless steel while preserving the stainless behavior. As a consequence of the thermochemical surface engineering, huge......: - plastic deformation of metastable austenitic stainless steels leads to the development of strain-induced martensite, which compromises the uniformity and the homogeneity of the expanded austenite zone. - during low temperature surface engineering composition and stress profiles develop. On numerical...

  7. Hardness analysis of welded joints of austenitic and duplex stainless steels

    Science.gov (United States)

    Topolska, S.

    2016-08-01

    Stainless steels are widely used in the modern world. The continuous increase in the use of stainless steels is caused by getting greater requirements relating the corrosion resistance of all types of devices. The main property of these steels is the ability to overlap a passive layer of an oxide on their surface. This layer causes that they become resistant to oxidation. One of types of corrosion-resistant steels is ferritic-austenitic steel of the duplex type, which has good strength properties. It is easily formable and weldable as well as resistant to erosion and abrasive wear. It has a low susceptibility to stress-corrosion cracking, to stress corrosion, to intercrystalline one, to pitting one and to crevice one. For these reasons they are used, among others, in the construction of devices and facilities designed for chemicals transportation and for petroleum and natural gas extraction. The paper presents the results which shows that the particular specimens of the ][joint representing both heat affected zones (from the side of the 2205 steel and the 316L one) and the weld are characterized by higher hardness values than in the case of the same specimens for the 2Y joint. Probably this is caused by machining of edges of the sections of metal sheets before the welding process, which came to better mixing of native materials and the filler metal. After submerged arc welding the 2205 steel still retains the diphase, austenitic-ferritic structure and the 316L steel retains the austenitic structure with sparse bands of ferrite σ.

  8. Aging degradation of cast stainless steels: Effects on mechanical properties

    International Nuclear Information System (INIS)

    A program is being conducted to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water operating conditions. Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320, and 2900C. The results indicate that thermal aging increases the tensile strength and decreases the impact energy, J/sub IC/, and tearing modulus of the steels. Also, the ductile-to-brittle transition curve shifts to higher temperatures. The fracture toughness results are consistent with the Charpy-impact data, i.e., the relative reduction in J/sub IC/ is similar to the relative decrease in impact energy. The ferrite content and concentration of C in the steel have a strong effect on the overall process of low-temperature embrittlement. The low-carbon CF-3 steels are the most resistant and Mo-containing CF-8M steels are most susceptible to embrittlement. Weakening of the ferrite/austenite phase boundaries by carbide precipitates has a significant effect on the kinetics and extent of embrittlement of the high-carbon CF-8 and CF-8M steels, particularly after aging at temperatures ≥4000C. The influence of N content and distribution of ferrite on loss of toughness are discussed. The data also indicate that existing correlations do not accurately represent the embrittlement behavior over the temperature range 280 to 4500C, i.e., extrapolation of high-temperature data to reactor temperatures may not be valid for some compositions of cast stainless steel

  9. Fabrication of a segmented composite stainless steel-alumina discharge tube for a theta-pinch coil

    International Nuclear Information System (INIS)

    An 80-mm-diam segmented discharge tube that simulated in a simplified way the blanket and first wall of the Reference Theta-Pinch Reactor (RTPR) has been constructed. The segments were fabricated by plasma-arc spraying an alumina coating on tubular stainless steel trapezoids. These were laid up to form a cylinder that was contained in a fully dense alumina vacuum tube. The fabrication processes are discussed in detail

  10. Thermal stability of ultrafine-grained austenitic stainless steels

    International Nuclear Information System (INIS)

    Ultrafine-grained 316 and 304 austenitic stainless steel samples have been produced by high pressure torsion. Their microstructure, after deformation and annealing at a temperature in the 350-900 deg. C range, has been characterized using several techniques (transmission electron microscopy, X-ray diffraction, Moessbauer spectroscopy). The average grain size in the ultrafine-grained 316 is about 40 nm while it is larger in the ultrafine-grained 304 due to a smaller deformation. Results show the formation of α'-martensite during deformation in both steels while ε-martensite is formed only in the 304 steel. Annealing at 350 deg. C induces the decrease of α'-martensite content in the 316 steel. The trend is different in the 304 steel, in which the α'-martensite content increases. Recrystallization of grains is observed from 700 deg. C. Moessbauer spectroscopy shows a reduction of the level of solute atoms in α'-martensite during annealing.

  11. 2012 ACCOMPLISHMENTS - TRITIUM AGING STUDIES ON STAINLESS STEELS

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, M.

    2013-01-31

    This report summarizes the research and development accomplishments during FY12 for the tritium effects on materials program. The tritium effects on materials program is designed to measure the long-term effects of tritium and its radioactive decay product, helium-3, on the structural properties of forged stainless steels which are used as the materials of construction for tritium reservoirs. The FY12 R&D accomplishments include: (1) Fabricated and Thermally-Charged 150 Forged Stainless Steel Samples with Tritium for Future Aging Studies; (2) Developed an Experimental Plan for Measuring Cracking Thresholds of Tritium-Charged-and-Aged Steels in High Pressure Hydrogen Gas; (3) Calculated Sample Tritium Contents For Laboratory Inventory Requirements and Environmental Release Estimates; (4) Published report on “Cracking Thresholds and Fracture Toughness Properties of Tritium-Charged-and-Aged Stainless Steels”; and, (5) Published report on “The Effects of Hydrogen, Tritium, and Heat Treatment on the Deformation and Fracture Toughness Properties of Stainless Steels”. These accomplishments are highlighted here and references given to additional reports for more detailed information.

  12. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    OpenAIRE

    Ayo Samuel AFOLABI; Alaneme, K.K.; Samson Oluwaseyi BADA

    2009-01-01

    The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in th...

  13. Toughness of welded stainless steels sheets for automotive industry

    Directory of Open Access Journals (Sweden)

    E. Bayraktar

    2011-01-01

    Full Text Available Purpose: In the automotive industry, more and more it is compulsory to develop new grades of stainless steels, such as high resistant Martensitic Stainless Steels (MA-SS and Ferritic Stainless Steels (FSS in order to realise certain or many complex deep drawn pieces. For these grades, resistance spot welding (RSW is the most widespread process used largely for many parts of the car body in the automotive industry. This paper aims to characterise mechanical behaviour (toughness of the different steel grades under dynamic test conditions.Design/methodology/approach: A special crash test device is used in different temperatures and the simulated crash tests are performed at a constant speed of 5.52 m/s.Findings: The specimen is submitted to impact tensile test at different temperatures. According to testing temperature, fracture mode varies: At low temperatures, brittle fracture occurs: due to stress concentration, fracture always occurs in the notched section. At high temperatures, the specimen fails by ductile fracture. Toughness of the steel sheets (base metals, BM or welded parts is well compared at different materials and test conditions.Research limitations/implications: Evaluation of welded thin sheets submitted to the dynamic loading in order to correlate in real service conditions in order to realize a useful correlation between the transition temperature and deep drawability can be used for evaluating of the welding conditions and also of the material characteristics. For detail study, this type of the test needs a standard formulation.Practical implications: This is a new conception of specimen and of the impact/crash machine. It is widely used in automotive industry for practical and economic reason to give rapid answers to designer and also steel makers for ranking the materials.Originality/value: New developed test called impact crash test for evaluating the toughness of thin welded joints (tailored blanks / mechanical assemblies in

  14. Failure of austenitic stainless steel tubes during steam generator operation

    Directory of Open Access Journals (Sweden)

    M. Głowacka

    2012-12-01

    Full Text Available Purpose: of this study is to analyze the causes of premature failure of steam generator coil made of austenitic stainless steel. Special attention is paid to corrosion damage processes within the welded joints.Design/methodology/approach: Examinations were conducted several segments of the coil made of seamless cold-formed pipes Ø 23x2.3 mm, of austenitic stainless steel grade X6CrNiTi18-10 according to EN 10088-1:2007. The working time of the device was 6 months. The reason for the withdrawal of the generator from the operation was leaks in the coil tube caused by corrosion damage. The metallographic investigations were performed with the use of light microscope and scanning electron microscope equipped with the EDX analysis attachment.Findings: Examinations of coil tubes indicated severe corrosion damages as pitting corrosion, stress corrosion cracking, and intergranular corrosion within base material and welded joints. Causes of corrosion was defined as wrong choice of austenitic steel grade, improper welding technology, lack of quality control of water supply and lack of surface treatment of stainless steel pipes.Research limitations/implications: It was not known the quality of water supply of steam generator and this was the reason for some problems in the identification of corrosion processes.Practical implications: Based on the obtained research results and literature studies some recommendations were formulated in order to avoid failures in the application of austenitic steels in the steam generators. These recommendations relate to the selection of materials, processing technology and working environment.Originality/value: Article clearly shows that attempts to increase the life time of evaporator tubes and steam coils by replacing non-alloy or low alloy structural steel by austenitic steel, without regard to restrictions on its use, in practice often fail.

  15. Deformation behavior of open-cell stainless steel foams

    Energy Technology Data Exchange (ETDEWEB)

    Kaya, A.C., E-mail: a.kaya@campus.tu-berlin.de; Fleck, C.

    2014-10-06

    This study presents the deformation and cell collapse behavior of open-cell stainless steel foams. 316L stainless-steel open-cell foams with two porosities (30 and 45 pores per inch, ppi) were produced with the pressureless powder metallurgical method, and tested in quasi-static compression. As a result of the manufacturing technique, 316L stainless steel open-cell foams have a high amount of microporosity. The deformation behavior was investigated on a macroscopic scale by digital image correlation (DIC) evaluation of light micrographs and on the microscopic scale by in situ loading of cells in the scanning electron microscope. The deformation behavior of the metal foams was highly affected by microstructural features, such as closed pores and their distribution throughout the foam specimen. Moreover, the closed pores made a contribution to the plateau stress of the foams through cell face stretching. Strut buckling and bending are the dominant mechanisms in cell collapse. Although there are edge defects on the struts, the struts have an enormous plastic deformation capability. The cell size of the steel foams had no significant effect on the mechanical properties. Due to the inhomogeneities in the microstructure, the measured plateau stresses of the foams showed about 20% scatter at the same relative density.

  16. High specialty stainless steels and nickel alloys for FGD dampers

    Energy Technology Data Exchange (ETDEWEB)

    Herda, W.R.; Rockel, M.B.; Grossmann, G.K. [Krupp VDM GmbH, Werdohl (Germany); Starke, K. [Mannesmann-Seiffert GmbH, Beckum (Germany)

    1997-08-01

    Because of process design and construction, FGD installations normally have bypass ducts, which necessitates use of dampers. Due to corrosion from acid dew resulting from interaction of hot acidic flue gases and colder outside environments, carbon steel cannot be used as construction material under these specific conditions. In the past, commercial stainless steels have suffered by pitting and crevice corrosion and occasionally failed by stress corrosion cracking. Only high alloy specialty super-austenitic stainless steels with 6.5% Mo should be used and considered for this application. Experience in Germany and Europe has shown that with regard to safety and life cycle cost analysis as well as providing a long time warranty, a new specialty stainless steel, alloy 31--UNS N08031--(31 Ni, 27 Cr, 6.5 Mo, 0.2 N) has proven to be the best and most economical choice. Hundreds of tons in forms of sheet, rod and bar, as well as strip (for damper seals) have been used and installed in many FGD installations throughout Europe. Under extremely corrosive conditions, the new advanced Ni-Cr-Mo alloy 59--UNS N06059--(59 Ni, 23 Cr, 16 Mo) should be used. This paper describes qualification and workability of these alloys as pertains to damper applications. Some case histories are also provided.

  17. Study of irradiation damage structures in austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Shozo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-08-01

    The irradiation damage microstructures in austenitic stainless steels, which have been proposed to be a candidate of structural materials of a fusion reactor, under ions and neutrons irradiation have been studied. In ion irradiation experiments, cross-sectional observation of the depth distribution of damage formed due to ion irradiation became available. Comparison and discussion between experimental results with TEM and the calculated ones in the depth profiles of irradiation damage microstructures. Further, dual-phase stainless steels, consisted of ferritic/austenitic phases, showed irradiation-induced/enhanced precipitation during ion irradiation. High Flux Isotope Reactor with high neutron fluxes was employed in neutron-irradiation experiments. Swelling of 316 steel showed irradiation temperature dependence and this had strong correlation with phase instability under heavy damage level. Swelling resistance of Ti-modified austenitic stainless steel, which has good swelling resistance, decreased during high damage level. This might be caused by the instability of Ti-carbide particles. The preparation method to reduce higher radioactivity of neutron-irradiated TEM specimen was developed. (author). 176 refs.

  18. Residual stresses and fatigue in a duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Johan

    1999-05-01

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  19. Residual stresses and fatigue in a duplex stainless steel

    International Nuclear Information System (INIS)

    Duplex stainless steels, consisting of approximately equal amounts of austenite and ferrite, often combine the best features of austenitic and ferritic stainless steels. They generally have good mechanical properties, including high strength and ductility, and the corrosion resistance is often better than conventional austenitic grades. This has lead to a growing use of duplex stainless steels as a material in mechanically loaded constructions. However, detailed knowledge regarding its mechanical properties and deformation mechanisms are still lacking. In this thesis special emphasis has been placed on the residual stresses and their influence on mechanical behaviour of duplex stainless steels. Due to the difference in coefficient of thermal expansion between the two phases, tensile microstresses are found in the austenitic phase and balancing compressive microstresses in the ferritic phase. The first part of this thesis is a literature survey, which will give an introduction to duplex stainless steels and review the fatigue properties of duplex stainless steels and the influence of residual stresses in two-phase material. The second part concerns the evolution of the residual stress state during uniaxial loading. Initial residual stresses were found to be almost two times higher in the transverse direction compared to the rolling direction. During loading the absolute value of the microstresses increased in the macroscopic elastic regime but started to decrease with increasing load in the macroscopic plastic regime. A significant increase of the microstresses was also found to occur during unloading. Finite element simulations also show stress variation within one phase and a strong influence of both the elastic and plastic anisotropy of the individual phases on the simulated stress state. In the third part, the load sharing between the phases during cyclic loading is studied. X-ray diffraction stress analysis and transmission electron microscopy show that even if

  20. A New Method to Produce Ni-Cr Ferroalloy Used for Stainless Steel Production

    Science.gov (United States)

    Chen, Pei-Xian; Chu, Shao-Jun; Zhang, Guo-Hua

    2016-08-01

    A new electrosilicothermic method has been proposed in the present paper to produce Ni-Cr ferroalloy, which can be used for the production of 300 series stainless steel. Based on this new process, the Ni-Si ferroalloy is first produced as the intermediate alloy, and then the desiliconization process of Ni-Si ferroalloy melt with chromium concentrate is carried out to generate Ni-Cr ferroalloy. The silicon content in the Ni-Si ferroalloy produced in the submerged arc furnace should be more than 15 mass% (for the propose of reducing dephosphorization), in order to make sure the phosphorus content in the subsequently produced Ni-Cr ferroalloy is less than 0.03 mass%. A high utilization ratio of Si and a high recovery ratio of Cr can be obtained after the desiliconization reaction between Ni-Si ferroalloy and chromium concentrate in the electric arc furnace (EAF)-shaking ladle (SL) process.

  1. High density sintered stainless steels with improved properties

    Directory of Open Access Journals (Sweden)

    M. Actis Grande

    2007-04-01

    Full Text Available Purpose: of this paper is the study of the properties of sintered AISI 316L (1.4404 according to EN 10088. Sintered stainless steels occupy a prominent position in the high alloyed steels, however their properties are limited by the presence of porosity. The improvement of quality and performances of products coupled with a reduction of manufacturing costs calls for high compacting pressures, as well as high sintering temperatures. However, the possibility to fill the open porosity of sintered parts by infiltration process with a metal alloy or by the use of reactive sintering techniques can favour the production of stainless steel parts with enhanced mechanical properties and good corrosion resistance. Design/methodology/approach: Sintered AISI 316L (1.4404 according to EN 10088 stainless steel samples have been manufactured using different combinations of compacting pressure and sintering parameters (time, temperature, atmosphere, or a modified composition able to allow reactive sintering process, as well as the contact infiltration with bronze.Findings: The studies have been forwarded towards the statical and dynamic mechanical properties, as well as the corrosion behavior. Lowering the porosity level and increasing the sintering degree, by use of higher compacting pressure or sintering temperature, is of great effectiveness, especially from the point of view of mechanical properties and fatigue endurance.Practical implications: the obtained results demonstrate the benefits of contact infiltration and of reactive sintering techniques to sinter stainless steels components having higher density and better mechanical and corrosion resistance properties than the traditional compositions, compacted at high pressure and sintered at elevated temperature.Originality/value: very promising results have been also obtained with a modified composition able to allow reactive sintering process.

  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 Effect of Welding Method on the Electrochemical Behavior of Austenitic Stainless Steel Sheet

    International Nuclear Information System (INIS)

    The corrosion of the flexible tube in the automobile exhaust system is caused by the ambient water and chloride ions. Since welding is one of the key processes of the flexible tube manufacturing, it is required to select a proper welding method to prevent the flexible tube corrosion and to increase its lifetime. There are many studies about the efficiency of the welding method, but no systematic study is performed for the effect of welding method on the corrosion property of the austenitic stainless weldment. The aim of the present study is to provide information on the effect of two different welding methods of TIGW (tungsten inert gas welding) and PAW (plasma arc welding) on the corrosion property of austenitic stainless steel weldment. Materials used in this study were two types of the commercial austenitic stainless steel, STS321 and XMI5JI, which were used for flexible tube material for the automotive exhaust system. Microstructure was observed by using optical microscopy (OM) and scanning electron microscopy (SEM). To evaluate the corrosion behavior, potentiodynamic and potentiostatic tests were performed. The chemical state of the passive film was analyzed in terms of XPS depth profile. Metallurgical analysis show that the ferrite content in fusion zone of both STS321 and XMI5JI is higher when welded by PAW than by TIGW. The potentiodynamic and potentiostatic test results show that both STS321 and XMI5JI have higher transpassive potential and lower passive current density when welded by PAW than by TIGW. XPS analysis indicates that the stable Cr2O3 layer at the outermost layer of the passive film is formed when welded by PAW. The result recommends that PAW is more desirable than TIGW to secure corrosion resistance of the flex tube which is usually made of austenitic stainless steel

  4. Corrosion behavior of niobium coated 304 stainless steel in acid solution

    Science.gov (United States)

    Pan, T. J.; Chen, Y.; Zhang, B.; Hu, J.; Li, C.

    2016-04-01

    The niobium coating is fabricated on the surface of AISI Type 304 stainless steel (304SS) by using a high energy micro arc alloying technique in order to improvecorrosion resistance of the steel against acidic environments. The electrochemical corrosion resistance of the niobium coating in 0.7 M sulfuric acid solutions is evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and the open circuit potential versus time. Electrochemical measurements indicate that the niobium coating increases the free corrosion potential of the substrate by 110 mV and a reduction in the corrosion rate by two orders of magnitude compared to the substrate alone. The niobium coating maintains large impedance and effectively offers good protection for the substrate during the long-term exposure tests, which is mainly ascribed to the niobium coating acting inhibiting permeation of corrosive species. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion resistance behavior of the niobium coating in acid solutions.

  5. Super austenitic stainless steels - a promising replacement for the currently used type 316L stainless steel as the construction material for flue-gas desulphurization plant

    Energy Technology Data Exchange (ETDEWEB)

    Rajendran, N.; Rajeswari, S. [University of Madras, Madras (India). Dept. of Analytical Chemistry

    1996-12-15

    Potentiodynamic anodic cyclic polarization experiments on type 316L stainless steel and 6Mo super austenitic stainless steels were carried out in simulated flue-gas desulphurization (FGD) environment in order to assess the localized corrosion resistance. The pitting corrosion resistance was higher in the case of the super austenitic stainless steel containing 6Mo and a higher amount of nitrogen. The accelerated leaching study conducted for the alloys showed that the super austenitic stainless steels have a little tendency for leaching of metal ions such as iron, chromium and nickel at different impressed potentials. This may be due to surface segregation of nitrogen as CrN, which would, in turn, enrich a chromium and molybdenum mixed oxide film and thus impede the release of metal ions. The present study indicates that the 6Mo super austenitics can be adopted as a promising replacement for the currently used type 316L stainless steel as the construction material for FGD plants.

  6. Mechanical and physical properties of irradiated type 348 stainless steel

    International Nuclear Information System (INIS)

    A type 348 stainless steel in-pile tube irradiated to a fluence of 3 x 1022 n/cm2, E > 1 MeV (57 dpa), was destructively examined. The service had resulted in a maximum total creep of 1.8% at the high fluence. The metal temperature ranged between 623 and 6520K, hence the thermal creep portion of the total was negligible. Total creep was greater than had been anticipated from creep data for austenitic stainless steels irradiated in other reactors. The objectives of the destructive examination were to determine the service-induced changes of mechanical and physical properties, and to assess the possibility of adverse effects of both these changes and the greater total creep on the prospective service life of other tubes

  7. Interaction between Lubricants Containing Phosphate Ester Additives and Stainless Steels

    Directory of Open Access Journals (Sweden)

    David W. Johnson

    2013-05-01

    Full Text Available One way to improve fuel efficiency in today’s jet aircraft engines is to create an environment for higher operating temperatures and speeds. New and improved lubricants and bearing materials must be developed to remain stable in these elevated operating temperatures. Three lubricants, with varying amounts of tricresyl phosphate added as an anti-wear/extreme pressure additive were tested on two different stainless steels at varying temperatures ranging from 300 °C to 350 °C in vacuum. Significant decomposition of the lubricant base-stocks and the phosphate ester additive did occur in most of the trials resulting in the formation of carboxylic acids and phenols. In these cases a film containing phosphorus was deposited onto the stainless steel substrate.

  8. Investigation of Laser Peening Effects on Hydrogen Charged Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Zaleski, Tania M. [San Jose State Univ., CA (United States)

    2008-10-30

    Hydrogen-rich environments such as fuel cell reactors can exhibit damage caused by hydrogen permeation in the form of corrosion cracking by lowering tensile strength and decreasing material ductility. Coatings and liners have been investigated, but there were few shot-peening or laser peening studies referenced in the literature with respect to preventing hydrogen embrittlement. The surface compressive residual stress induced by laser peening had shown success in preventing stress corrosion cracking (SCC) for stainless steels in power plants. The question arose if the residual stresses induced by laser peening could delay the effects of hydrogen in a material. This study investigated the effect of laser peening on hydrogen penetration into metal alloys. Three areas were studied: laser peening, hydrogenation, and hydrogen detection. This study demonstrated that laser peening does not reduce the hydrogen permeation into a stainless steel surface nor does it prevent hydrogen embrittlement. The effect of laser peening to reduce hydrogen-assisted fatigue was unclear.

  9. 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.

  10. Long-Term Underground Corrosion of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    M. K. Adler Flitton; T. S. Yoder

    2007-03-01

    In 1970, the National Institute of Standards and Technology (NIST) implemented the most ambitious and comprehensive long-term corrosion behavior test to date for stainless steels in soil environments. Over thirty years later, one of the six test sites was targeted to research subsurface contamination and transport processes in the vadose and saturated zones. This research directly applies to environmental management operational corrosion issues and long term stewardship scientific needs for understanding the behavior of waste forms and their near-field contaminant transport of chemical and radiological contaminants at nuclear disposal sites. This paper briefly describes the ongoing research and the corrosion analysis results of the stainless steel plate specimens recovered from the partial recovery of the first test site.

  11. Multilayer modelling of stainless steel with a nanocrystallised superficial layer

    Energy Technology Data Exchange (ETDEWEB)

    Petit, J. [Laboratoire Energetique Mecanique Electromagnetisme (LEME), EA4416, Universite Paris Ouest, 92410 Ville d' Avray (France); Waltz, L., E-mail: laurent.waltz@univ-montp2.fr [Laboratoire de Mecanique et Genie Civil de Montpellier (LMGC), University of Montpellier II, Place Eugene Bataillon, 34000 Montpellier (France); Montay, G.; Retraint, D.; Roos, A.; Francois, M. [Institut Charles Delaunay - LASMIS, UMR CNRS 6279, University of Technology of Troyes, 10010 Troyes (France)

    2012-02-28

    Highlights: Black-Right-Pointing-Pointer SMAT has been used for nanocrystallisation of an austenitic stainless steel. Black-Right-Pointing-Pointer The mechanical response of the nano-phase has been obtained by an indirect method. Black-Right-Pointing-Pointer Minimisation of a stress formulated objective function. Black-Right-Pointing-Pointer The model predicts the strain at which diffuse necking occurs. - Abstract: In order to obtain the macroscopic mechanical response of a 316L stainless steel, nanocrystallised by Surface Mechanical Attrition Treatment (SMAT), a multilayer model is proposed. The constitutive behaviour of each layer is determined from tensile tests or by an inverse method and its thickness is evaluated from Scanning and Transmission Electron Microscopy (SEM and TEM) analyses and local hardness measurements. The consistency of the model is verified by its ability to predict the strain at which diffuse necking occurs.

  12. PITTING CORROSION OF STAINLESS STEEL AT THE VARIOUS SURFACE TREATMENT

    Directory of Open Access Journals (Sweden)

    Viera Zatkalíková

    2011-09-01

    Full Text Available The stainless steel surface treatment is very important with regard to its pitting corrosion susceptibility. An effect of various types surfacing on pitting corrosion resistance of AISI 304stainless steel is investigated in this work. The samples of the tested material are turned, blasted, peened, grinded and a half of them are pickled to achieve higher purity of surfaces and better quality of passive film. Eight types of different finished surfaces are tested by electrochemical and immersion tests to determine corrosion behaviour in conditions where pitting is evoked by controlled potential and second by solution with high redox potential. By this way the effect of mechanical and chemical surface treatment on the resistance to pitting corrosion, character, size and shape of pits are compared in the conditions of different mechanisms of corrosion process.

  13. New hermetic sealing material for vacuum brazing of stainless steels

    Science.gov (United States)

    Hildebrandt, S.; Wiehl, G.; Silze, F.

    2016-03-01

    For vacuum brazing applications such as in vacuum interrupter industry Hermetic Sealing Materials (HSM) with low partial pressure are widely used. AgCu28 dominates the hermetic sealing market, as it has a very good wetting behavior on copper and metallized ceramics. Within recent decades wetting on stainless steel has become more and more important. However, today the silver content of HSMs is more in focus than in the past decades, because it has the biggest impact on the material prices. Umicore Technical Materials has developed a new copper based HSM, CuAg40Ga10. The wettability on stainless steel is significantly improved compared to AgCu28 and the total silver content is reduced by almost 44%. In this article the physical properties of the alloy and its brazed joints will be presented compared to AgCu28.

  14. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    Directory of Open Access Journals (Sweden)

    Ayo Samuel AFOLABI

    2009-07-01

    Full Text Available The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in the structure of duplex stainless steel coupled with higher content of chromium in its composition. Both steels produced electrochemical noise at increased concentrations of lithium bromide due to continuous film breakdown and repair caused by reduction in medium concentration by the alkaline corrosion product while surface passivity observed in duplex stainless steel is attributed to film stability on this steel.

  15. Surface nanocrystallization of stainless steel for reduced biofilm adherence.

    Science.gov (United States)

    Yu, Bin; Davis, Elisabeth M; Hodges, Robert S; Irvin, Randall T; Li, D Y

    2008-08-20

    Stainless steel is one of the most common metallic biomedical materials. For medical applications, its resistance to the adherence of biofilms is of importance to the elimination or minimization of bacterial infections. In this study, we demonstrate the effectiveness of a process combining surface nanocrystallization and thermal oxidation (or a recovery heat treatment in air) for reducing the biofilm's adherence to stainless steel. During this treatment, a target surface was sandblasted and the resultant dislocation cells in the surface layer were turned into nanosized grains by a subsequent recovery treatment in air. This process generated a more protective oxide film that blocked the electron exchange or reduced the surface activity more effectively. As a result, the biofilm's adherence to the treated surface was markedly minimized. A synthetic peptide was utilized as a substitute of biofilms to evaluate the adhesion between a treated steel surface and biofilms using an atomic force microscope (AFM) through measuring the adhesive force between the target surface and a peptide-coated AFM tip. It was shown that the adhesive force decreased with a decrease in the grain size of the steel. The corresponding surface electron work function (EWF) of the steel was also measured, which showed a trend of variation in EWF with the grain size, consistent with corresponding changes in the adhesive force. PMID:21730615

  16. Ionic nitriding of high chromium martensitic stainless steels

    International Nuclear Information System (INIS)

    Martensitic stainless steels are used in industrial applications where resistance to corrosion and mechanical resistance are needed simultaneously. These steels are normally used in tempering and annealing condition which gives them hardnesses of 500 and 600 HV (about 54 HRC). Ionic nitriding is an assisted diffusion technique that has recently been successfully applied to harden austenitic stainless steels without reducing their resistance to corrosion. The application with AISI 420 martensitic steels has not given good results yet, because in most cases, it affects their corrosion resistance. This work presents the results of the pulsed nitriding of martensitic steels with a higher chrome content, such as the M340 and M333 Boehler steels and they are compared with the same materials after tempering and annealing, without nitriding. The influence of the variations in the parameters of the process, such as the percentage of active time in the pulsed wave, partial nitrogen pressure, current density and effective tension in the microstructure, hardness and wear and corrosion resistance was studied. The microstructure was studied with an optic microscope; the wear resistance with abrasion tests following ASTM G-65 and corrosion with 100 hour long saline haze tests, in a device built according to ASTM B117. Hardness was found to rise to values of 1000 to 1350 HV in all the steels after ionic nitriding, the modified layers oscillated from 3 to 15 microns. As a result, wear resistance also increased, with differences depending on the microstructure and the thickness of the modified layer. However, corrosion resistance was not good, except in the case of the M333 steel test piece with less hardness and a less thick nitrided layer without a noticeable interphase (au)

  17. Highly alloyed stainless steels for sea water applications

    Energy Technology Data Exchange (ETDEWEB)

    Audouard, J.P.; Verneau, M. [Creusot-Loire Industrie, Le Creusot (France). Research Centre for Materials

    1996-10-01

    Natural sea water is known as a very aggressive environment which generates pitting and crevice corrosion on stainless steels. High chromium grades with sufficient molybdenum and nitrogen additions (PREN > 40) are generally recognized as resistant materials in natural sea water bu the material selection criteria must be improved to take into account the effect of climatic conditions and of biocide treatments which are widely used as anti-fouling agents in sea water circuits. The paper deals with the localized corrosion properties of conventional stainless steels (SS), duplex and superaustenitic alloys. The results of laboratory investigations conducted in more or less oxidizing chloride containing media are discussed. Then, immersion tests carried out in natural sea waters in different climatic conditions are presented and discussed. Finally, the effect of biocide addition on fouling and its consequences on corrosion is investigated. The results are interpreted taking into account the chemical composition of the stainless steels and biofilm criteria. The results showed the Mediterranean Sea to be slightly more aggressive than other European seas but a PREN value higher than 40 is sufficient for stainless steels to withstand localized corrosion in European natural sea waters. A residual chlorine level around 0.3--0.4 ppm was found to be very effective to limit the fouling and to avoid localized corrosion on SS. Nevertheless, due to difficulties in monitoring chlorine addition, PREN values higher than 50 are recommended to withstand localized corrosion in treated sea waters. As an example, the new super-austenitic grade 25Cr-22Ni-5.8Mo-1.5Cu-2W-0.45N with a PRENW value of 54 was found to be perfectly resistant to crevice corrosion with 0.5 ppm free chlorine at ambient temperature.

  18. Adhesive bonding of stainless steel : strength and durability

    OpenAIRE

    Boyes, Robert

    1998-01-01

    Adhesive bonding as an alternative method of joining materials together has many advantages over the more conventional joining methods such as fusion and spot welding, bolting and riveting. For example, adhesives can be used to bond dissimilar materials, adhesive joints have a high stiffness to weight ratio and the stress distribution within the joint is much improved. Stainless steels are commonly used in applications that would clearly benefit from adhesive bonding; architectural cladding, ...

  19. Modeling and optimization of turning duplex stainless steels

    OpenAIRE

    Ali, Rastee Dalshad

    2015-01-01

    In the present dissertation, machining investigations into duplex stainless steels are performed under different and systematically well-structured modeling and optimization frameworks. Focusing on the main objective of finding optimum machining process parameters and com-prehensively applying the statistical design of experiments to design the experiments, the study tackles the challenge of integrating modeling and optimization algorithms using six different approaches. Firstly, sets of non-...

  20. Manifestations of DSA in austenitic stainless steels and inconel alloys

    International Nuclear Information System (INIS)

    The aim of the investigation was to examine and compare different types of DSA (Dynamic Strain Aging) manifestations in AISI 316 austenitic stainless steel (SS) and Inconel 600 and Inconel 690 alloys by means of slow strain rate tensile testing, mechanical loss spectrometry (internal friction) and transmission electron microscopy (TEM). Another aim was to determine differences in the resulting dislocation structures and internal friction response of materials showing and not showing DSA behaviour

  1. Stainless steel: Recovery of properties after exposure to detrimental phases

    OpenAIRE

    Skaare, Andreas

    2015-01-01

    High alloyed stainless steel provides a desirable combination of corrosion resistance and mechanical properties, being a preferred material when ductility, overall strength and resistance to harsh environments are required. High service temperatures where alloy elements, as chromium and molybdenum, are present, is a well-known recipe for the precipitation of detrimental phases in the material. Even a small amount of these precipitations may impair the mechanical and corrosion properties. T...

  2. Intragranular Chromium Nitride Precipitates in Duplex and Superduplex Stainless Steel

    OpenAIRE

    Iversen, Torunn Hjulstad

    2012-01-01

    Intragranular chromium nitrides is a phenomenon with detrimental effects on material properties in superduplex stainless steels which have not received much attention. Precipitation of nitrides occurs when the ferritic phase becomes supersaturated with nitrogen and there is insufficient time during cooling for diffusion of nitrogen into austenite. Heat treatment was carried out at between 1060◦C and 1160◦C to study the materials susceptibility to nitride precipitation with...

  3. 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...... of the sample surface. The development of epsilon nitride, expanded austenite and expanded martensite resulted from the low temperature nitriding treatments. The microstructural features, hardness and phase composition are discussed with emphasis on the influence of nitriding duration and nitriding potential....

  4. Chromium reduction from slag on electromelting of stainless steel

    International Nuclear Information System (INIS)

    Specific features of chromium reduction from the slag on electromelting of stainless steel type Kh18N10T according to one- or two-slag procedure were studied. It was shown that one-slag melting technology allows double decrease of chromium losses in the form of incompletely reduced oxides. This occurs due to additional chemical reactions between metal and slag on their combined pouring into the ladle. 1 ref.; 3 figs

  5. Increase of chromium utilization in stainless steel melting

    International Nuclear Information System (INIS)

    The processes of deoxidizing when melting stainless 18-10 steels in electric are furnaces by the method of remelting with wastes are investigated. The dependences of amount of reduced chromium on silicon consumption are made more precise. It is shown that it is useful to apply aluminium for deoxidation of acid high-chromium slags. Based on the data on pilot melts the extent to which aluminium can be used as a reducing agent for chromium is estimated. 3 refs., 2 figs

  6. Stabilization of final titanium concentration in stainless steel

    International Nuclear Information System (INIS)

    The technology of combined alloying of stainless steel type 08-12Kh18N10T with 30%-ferrotitanium and metallic spongy titanium is developed and put into practice. This permits to stabilize titanium assimilation at the level of 40-60 % in two-slag melting process and to increase chromium recovering from the slag. Stabilization of titanium assimilation promotes its homogeneous distribution in final metal after electroslag remelting. 2 refs. 3 figs

  7. 75 FR 67689 - Stainless Steel Bar From Brazil: Preliminary Results of Antidumping Duty Administrative Review

    Science.gov (United States)

    2010-11-03

    ... Brazil. See Antidumping Duty Orders: Stainless Steel Bar from Brazil, India and Japan, 60 FR 9661... Steel Bar From Brazil: Preliminary Results of Antidumping Duty Administrative Review, 74 FR 10022 (March... market. \\2\\ These results were unchanged in the final results of review (Stainless Steel Bar From...

  8. 46 CFR 148.04-13 - Ferrous metal borings, shavings, turnings, or cuttings (excluding stainless steel).

    Science.gov (United States)

    2010-10-01

    ... (excluding stainless steel). 148.04-13 Section 148.04-13 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... stainless steel). (a) This section applies to the stowage and transportation in bulk of hazardous materials... steel). However, unmanned barges on which the article is stowed for or transported on a voyage...

  9. Corrosion resistance properties of sintered duplex stainless steel

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2006-09-01

    Full Text Available Purpose: of this paper was to examine the corrosion resistance of duplex stainless steels using electrochemical methods in 1M NaCl solution. The influence of powder mixes preparation and cooling cycle after sintering on corrosion properties was evaluated.Design/methodology/approach: In presented study duplex stainless steels were obtained through powder metallurgy starting from austenitic, martensitic base powders by controlled addition of alloying elements, such as Cr, Ni, Mo and Cu. In the studies behind the preparation of mixes, Schaeffler’s diagram was taken into consideration. Prepared mixes have been compacted at 800 MPa and sintered in a vacuum furnace with argon backfilling at 1260°C for 1 h. After sintering two different cooling cycles were applied: rapid cooling with an average cooling rate of 245 °C/min and slow cooling of 5 °C/min in argon atmosphere. Produced duplex stainless steels have been studied by scanning and optical microscopy and EDS chemical analysis of microstructure components. Corrosion properties have been studied through electrochemical methods in 1M NaCl water solutionFindings: According to achieved results, it was affirmed that applied sintering method as well as powder mixes preparation allows for manufacturing the sintered duplex steels with good corrosion properties which depends on austenite/ferrite ratio in the microstructure and elements partitioning between phases. Corrosion resistance of sintered stainless steels is strictly connected with the density and the pore morphology present in the microstructure too. The highest resistance to pitting corrosion in 1M NaCl solution was achieved for composition with approximate balance of ferrite and austenite in the microstructure.Research limitations/implications: According to the powders characteristic, the applied fast cooling rate seems to be a good compromise for corrosion properties and microstructures, nevertheless further tests should be carried out in

  10. Mechanical Properties of Austenitic Stainless Steel Made by Additive Manufacturing.

    Science.gov (United States)

    Luecke, William E; Slotwinski, John A

    2014-01-01

    Using uniaxial tensile and hardness testing, we evaluated the variability and anisotropy of the mechanical properties of an austenitic stainless steel, UNS S17400, manufactured by an additive process, selective laser melting. Like wrought materials, the mechanical properties depend on the orientation introduced by the processing. The recommended stress-relief heat treatment increases the tensile strength, reduces the yield strength, and decreases the extent of the discontinuous yielding. The mechanical properties, assessed by hardness, are very uniform across the build plate, but the stress-relief heat treatment introduced a small non-uniformity that had no correlation to position on the build plate. Analysis of the mechanical property behavior resulted in four conclusions. (1) The within-build and build-to-build tensile properties of the UNS S17400 stainless steel are less repeatable than mature engineering structural alloys, but similar to other structural alloys made by additive manufacturing. (2) The anisotropy of the mechanical properties of the UNS S17400 material of this study is larger than that of mature structural alloys, but is similar to other structural alloys made by additive manufacturing. (3) The tensile mechanical properties of the UNS S17400 material fabricated by selective laser melting are very different from those of wrought, heat-treated 17-4PH stainless steel. (4) The large discontinuous yielding strain in all tests resulted from the formation and propagation of Lüders bands.

  11. Thermo-mechanical behavior of stainless steel knitted structures

    Science.gov (United States)

    Hamdani, Syed Talha Ali; Fernando, Anura; Maqsood, Muhammad

    2016-09-01

    Heating fabric is an advanced textile material that is extensively researched by the industrialists and the scientists alike. Ability to create highly flexible and drapeable heating fabrics has many applications in everyday life. This paper presents a study conducted on the comparison of heatability of knitted fabric made of stainless steel yarn. The purpose of the study is to find a suitable material for protective clothing against cold environments. In the current research the ampacity of stainless steel yarn is observed in order to prevent the overheating of the heating fabrics. The behavior of the knitted structure is studied for different levels of supply voltage. Infrared temperature sensing is used to measure the heat generated from the fabrics in order to measure the temperature of the fabrics without physical contact. It is concluded that interlock structure is one of the most suited structures for knitted heating fabrics. As learnt through this research, fabrics made of stainless steel yarn are capable of producing a higher level of heating compared to that of knitted fabric made using silver coated polymeric yarn at the same supply voltage.

  12. Thermal Aging Phenomena in Cast Duplex Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Thak Sang; Yang, Ying; Overman, Nicole R.; Busby, Jeremy T.

    2016-02-28

    Cast stainless steels (CASSs) have been extensively used for the large components of light water reactor (LWR) power plants such as primary coolant piping and pump casing. The thermal embrittlement of CASS components is one of the most serious concerns related to the extended-term operation of nuclear power plants. Many past researches have concluded that the formation of Cr–rich α'-phase by Spinodal decomposition of δ-ferrite phase is the primary mechanism for the thermal embrittlement. Cracking mechanism in the thermally-embrittled duplex stainless steels consists of the formation of cleavage at ferrite and its propagation via separation of ferrite-austenite interphase. This article intends to provide an introductory overview on the thermal aging phenomena in LWR relevant conditions. Firstly, the thermal aging effect on toughness is discussed in terms of the cause of embrittlement and influential parameters. An approximate analysis of thermal reaction using Arrhenius equation was carried out to scope the aging temperatures for the accelerated aging experiments to simulate the 60 and 80 years of services. Further, equilibrium precipitation calculation was performed for model CASS alloys using the CALPHAD program and the results are used to describe the precipitation behaviors in duplex stainless steels. These results are also to be used to guide an on-going research aiming to provide knowledge-based conclusive prediction for the integrity of the CASS components of LWR power plants during the service life extended up to and beyond 60 years.

  13. Thermal Aging Phenomena in Cast Duplex Stainless Steels

    Science.gov (United States)

    Byun, T. S.; Yang, Y.; Overman, N. R.; Busby, J. T.

    2016-02-01

    Cast stainless steels (CASSs) have been extensively used for the large components of light water reactor (LWR) power plants such as primary coolant piping and pump casing. The thermal embrittlement of CASS components is one of the most serious concerns related to the extended-term operation of nuclear power plants. Many past researches have concluded that the formation of Cr-rich α'-phase by Spinodal decomposition of δ-ferrite phase is the primary mechanism for the thermal embrittlement. Cracking mechanism in the thermally-embrittled duplex stainless steels consists of the formation of cleavage at ferrite and its propagation via separation of ferrite-austenite interphase. This article intends to provide an introductory overview on the thermal aging phenomena in LWR-relevant conditions. Firstly, the thermal aging effect on toughness is discussed in terms of the cause of embrittlement and influential parameters. An approximate analysis of thermal reaction using Arrhenius equation was carried out to scope the aging temperatures for the accelerated aging experiments to simulate the 60 and 80 years of services. Further, an equilibrium precipitation calculation was performed for model CASS alloys using the CALPHAD program, and the results are used to describe the precipitation behaviors in duplex stainless steels. These results are also to be used to guide an on-going research aiming to provide knowledge-based conclusive prediction for the integrity of the CASS components of LWR power plants during the service life extended up to and beyond 60 years.

  14. Adsorption of ammonia on treated stainless steel and polymer surfaces

    Science.gov (United States)

    Vaittinen, O.; Metsälä, M.; Persijn, S.; Vainio, M.; Halonen, L.

    2014-05-01

    Adsorption of dynamically diluted ammonia at part-per-billion to low part-per-million concentrations in dry nitrogen was studied with treated and non-treated stainless steel and polymer test tubes. The treatments included electropolishing and two types of coatings based on amorphous silicon. Cavity ring-down spectroscopy with an external cavity diode laser operating in the near-infrared wavelength range was used to monitor the adsorption process in real time in continuous-flow conditions to obtain quantitative assessment of the adsorptive properties of the studied surfaces. The investigated polymers were all less adsorptive than any of the treated or non-treated stainless steel surfaces. Some of the commercial coatings reduced the adsorption loss of stainless steel by a factor of ten or more. Polyvinylidene fluoride was found to be superior (less adsorption) to the four other studied polymer coatings. The number of adsorbed ammonia molecules per surface area obtained at different ammonia gas phase concentrations was modeled with Langmuir and Freundlich isotherms. The time behavior of the adsorption-desorption process occurring in the time scale of seconds and minutes was simulated with a simple kinetic model.

  15. [Clinical evaluation of gingival tissue restored with stainless steel crown].

    Science.gov (United States)

    Chao, D D; Tsai, T P; Chen, T C

    1992-12-01

    The use of stainless steel crown for the restoration of primary molars is widely accepted in pediatric dentistry. There has been a concern regarding their effect on the health of the gingival tissue. It is a possibility that the preformed crown may be a contributing cause of gingivitis. This study evaluated one hundred and thirty-seven crowns in forty-five patients who had received pedodontic treatment at Chang Gung Memorial Hospital. The results indicated that the majority of stainless steel crowns had one or more defects, with crown crimping being the most common error. According to what the paired t-test showed, non-ideal crowns indicated that the gingival index was significantly higher than the entire mouth and control teeth. However the supragingival plaque accumulation of these teeth was significant lower than the entire mouth and control teeth. There was only a moderate positive correlation between supragingival plaque and gingivitis. The operator is necessary to adapt the stainless steel crown margin as closely as possible to the tooth and to avoid the mechanical defect of a crown. It minimizes the irritation of gingival tissue and diminishes the bacterial adherence of subgingival plaque, therefore preserving the health of gingival tissue.

  16. Surface interactions of cesium and boric acid with stainless steel

    International Nuclear Information System (INIS)

    In this report, the effects of cesium hydroxide and boric acid on oxidized stainless steel surfaces at high temperatures and near one atmosphere of pressure are investigated. This is the first experimental investigation of this chemical system. The experimental investigations were performed using a mass spectrometer and a mass electrobalance. Surfaces from the different experiments were examined using a scanning electron microscope to identify the presence of deposited species, and electron spectroscopy for chemical analysis to identify the species deposited on the surface. A better understanding of the equilibrium thermodynamics, the kinetics of the steam-accelerated volatilizations, and the release kinetics are gained by these experiments. The release rate is characterized by bulk vaporization/gas-phase mass transfer data. The analysis couples vaporization, deposition, and desorption of the compounds formed by cesium hydroxide and boric acid under conditions similar to what is expected during certain nuclear reactor accidents. This study shows that cesium deposits on an oxidized stainless steel surface at temperatures between 1000 and 1200 Kelvin. Cesium also deposits on stainless steel surfaces coated with boric oxide in the same temperature ranges. The mechanism for cesium deposition onto the oxide layer was found to involve the chemical reaction between cesium and chromate. Some revaporization in the cesium hydroxide-boric acid system was observed. It has been found that under the conditions given, boric acid will react with cesium hydroxide to form cesium metaborate. A model is proposed for this chemical reaction

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

    Directory of Open Access Journals (Sweden)

    MilesM.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.

  18. Crevice Corrosion of 321 Stainless Steel in Sodium Chloride Solutions

    International Nuclear Information System (INIS)

    Electrochemical techniques have been applied to study the crevice corrosion behaviour of stabilized 321 stainless steel in both 0.5, 1 and 2 M sodium chloride solutions at 25 and 80 degree . This type of stainless steel enjoys a good corrosion resistance especially in the heat affected zone (Haz) of welds. In this investigation the crevice corrosion of 321 stainless steel was studied in both bulk solution environments as well as in chloride solutions simulating those formed inside crevices. A metal-to-nonmetal crevice assembly, in which disc type specimens were faced to a PTFE crevice former, is used for bulk solution tests. Crevice-free specimens of solutions formed inside crevices (known as the critical crevice solutions, CCS). Cyclic potentiodynamic technique was used in evaluating the electrochemical corrosion performance of the alloy in bulk (0.5 and 1 M Nacl) environment. This revealed that both chloride ion concentration and temperature have a marked effect on the electrochemical parameters generally used for the evaluation of the crevice corrosion susceptibility. This included the corrosion potential. E corr. The passivity breakdown potential, Eb, and the protection potential, E p

  19. Long term thermal aging of cast duplex stainless steels

    International Nuclear Information System (INIS)

    Cast duplex stainless steels of CF8M and CF8 are used in major components because of their superior characteristics, such as corrosion resistance, weldability and so on. But, these stainless steels are known to have tendency of thermal aging embrittlement after long term service. Therefore, mechanical properties and metallurgical structure were investigated using materials aged at 290--400 C up to 30,000 hours. As the results show, effects of thermal aging on mechanical properties and metallurgical behavior were identified. In addition, prediction method for Charpy absorbed energy and fracture toughness was established. The following results have been obtained: (1) it was recognized that Charpy absorbed energy and fracture toughness tend to decrease and the tensile strength tend to increase with the increasing aging time; (2) it was confirmed that thermal aging embrittlement was caused by the phase separation in ferrite from the test results of APFIM; (3) in the degradation prediction model development the prediction model was applied to the material test data, including materials aged for 30,000 hours. As the results, the degradation prediction formulas for CVRT, CVHT, JIC and J6 were obtained. The toughness of cast duplex stainless steels during service could be estimated from chemical composition using this method

  20. Long term thermal aging of cast duplex stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Isao; Koyama, Masakuni [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Kawaguchi, Seiichi [Mitsubishi Heavy Industries, Ltd., Takasago (Japan); Mimaki, Hidehito [Mitsubishi Heavy Industries, Ltd., Kobe (Japan); Akiyama, Mamoru; Mishima, Yoshitsugu [Univ. of Tokyo (Japan); Okubo, Tadatsune [Sophia Univ., Tokyo (Japan); Mager, T.R.

    1996-09-01

    Cast duplex stainless steels of CF8M and CF8 are used in major components because of their superior characteristics, such as corrosion resistance, weldability and so on. But, these stainless steels are known to have tendency of thermal aging embrittlement after long term service. Therefore, mechanical properties and metallurgical structure were investigated using materials aged at 290--400 C up to 30,000 hours. As the results show, effects of thermal aging on mechanical properties and metallurgical behavior were identified. In addition, prediction method for Charpy absorbed energy and fracture toughness was established. The following results have been obtained: (1) it was recognized that Charpy absorbed energy and fracture toughness tend to decrease and the tensile strength tend to increase with the increasing aging time; (2) it was confirmed that thermal aging embrittlement was caused by the phase separation in ferrite from the test results of APFIM; (3) in the degradation prediction model development the prediction model was applied to the material test data, including materials aged for 30,000 hours. As the results, the degradation prediction formulas for CVRT, CVHT, J{sub IC} and J{sub 6} were obtained. The toughness of cast duplex stainless steels during service could be estimated from chemical composition using this method.

  1. Passivation of duplex stainless steel in solutions simulating chloride-contaminated concrete

    OpenAIRE

    Takenouti, H.; Soriano, L; Palacín, S.; Gutiérrez, A.; Velasco, F.; Blanco, G; Bautista, A.

    2007-01-01

    Most studies published to date on the corrosion behaviour of stainless reinforcing steel are based on austenitic steel. The market presence of corrugated duplex steel is growing, however. The present study compared passivity in 2205 type duplex and 304 type austenitic stainless steel. Polarization tests in chloride-containing Ca(OH)2 solutions confirmed the exceptional performance of duplex steels. X-ray photoelectronic spectroscopy (XPS) showed that the passive layer generated on duplex stai...

  2. Microbially influenced corrosion of stainless steels; Stainless ko no biseibutsu fushoku ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Y.; Misawa, M. [Kansai Electric Power Co. Inc., Osaka (Japan)

    1998-11-30

    It is generally known, though not fully clarified, that stainless steel pipes, particularly those exposed to natural sea water; are susceptible to microbially influenced corrosion (MIC) at welded joints. In an effort to gain a better understanding of the mechanism, factors affecting the MIC behavior in welded stainless steel pipe joints were experimentally investigated. Results of the study indicate there are two major contributing factors to MIC development in the weld region. One is the circumferentially protruding shape effect of the deposited metal, provinding an environment that allows aquatic microorganisms to adhere to the downstream side of the welded bead surface. The other factor is the declining corrosion resistance in the welded joint due to the oxide film formation caused by insufficient shielding during welding. There factors, if combined, produce higher susceptibility to MIC in the weld than in the base metal. (author)

  3. Microstructural characterization in dissimilar friction stir welding between 304 stainless steel and st37 steel

    Energy Technology Data Exchange (ETDEWEB)

    Jafarzadegan, M. [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China); Feng, A.H. [State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China); Abdollah-zadeh, A., E-mail: zadeh@modares.ac.ir [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Saeid, T. [Advanced Materials Research Center, Sahand University of Technology, P.O. Box: 51335-1996, Tabriz (Iran, Islamic Republic of); Shen, J. [State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China); Assadi, H. [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of)

    2012-12-15

    In the present study, 3 mm-thick plates of 304 stainless steel and st37 steel were welded together by friction stir welding at a welding speed of 50 mm/min and tool rotational speed of 400 and 800 rpm. X-ray diffraction test was carried out to study the phases which might be formed in the welds. Metallographic examinations, and tensile and microhardness tests were used to analyze the microstructure and mechanical properties of the joint. Four different zones were found in the weld area except the base metals. In the stir zone of the 304 stainless steel, a refined grain structure with some features of dynamic recrystallization was evidenced. A thermomechanically-affected zone was characterized on the 304 steel side with features of dynamic recovery. In the other side of the stir zone, the hot deformation of the st37 steel in the austenite region produced small austenite grains and these grains transformed to fine ferrite and pearlite and some products of displacive transformations such as Widmanstatten ferrite and martensite by cooling the material after friction stir welding. The heat-affected zone in the st37 steel side showed partially and fully refined microstructures like fusion welding processes. The recrystallization in the 304 steel and the transformations in the st37 steel enhanced the hardness of the weld area and therefore, improved the tensile properties of the joint. - Highlights: Black-Right-Pointing-Pointer FSW produced sound welds between st37 low carbon steel and 304 stainless steel. Black-Right-Pointing-Pointer The SZ of the st37 steel contained some products of allotropic transformation. Black-Right-Pointing-Pointer The material in the SZ of the 304 steel showed features of dynamic recrystallization. Black-Right-Pointing-Pointer The finer microstructure in the SZ increased the hardness and tensile strength.

  4. Microstructure and properties of composite of stainless steel and partially stabilized zirconia

    Institute of Scientific and Technical Information of China (English)

    张文泉; 谢建新; 杨志国; 王从曾

    2003-01-01

    To fabricate the metal-ceramics multi-layer hollow functionally gradient materials(FGMs) that mightmeet the requirement of repeated service and long working time of high temperature burners, such as spacecraft en-gine, the microstructure and properties of composite of stainless steel and partially stabilized zirconia were investiga-ted. Samples of different proportions of stainless steel to partially yttria-stabilized zirconia were fabricated by powderextrusion and sintering method. Shrinkage, relative density, microstructure, micro-Vickers hardness, compressionstrength, bending strength, fractography morphology and electrical resistivity of sintered samples with differentproportions of stainless steel were measured. The results show that threshold of metallic matrix composite(MMC)is approximately equal to 60 % (volume fraction) stainless steel. The samples with 0 to 50% (volume fraction) stain-less steel indicate ceramic brittleness and non cutability, and the samples with 70% to 100% (volume fraction) stain-less steel indicate metallic plasticity and cutability.

  5. EFFECT OF INTERMETALLIC PHASES ON CORROSION BEHAVIOR AND MECHANICAL PROPERTIES OF DUPLEX STAINLESS STEEL AND SUPER-DUPLEX STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Prabhu Paulraj

    2015-08-01

    Full Text Available Duplex Stainless Steels (DSS and Super Duplex Stainless Steel (SDSS have excellent integration of mechanical and corrosion properties. However, the formation of intermetallic phases is a major problem in their usage. The mechanical and corrosion properties are deteriorated due to the presence of intermetallic phases. These phases are induced during welding, prolonged exposure to high temperatures, and improper heat treatments. The main emphasis of this review article is on intermetallic phases and their effects on corrosion and mechanical properties. First the effect of various alloying elements on DSS and SDSS has been discussed followed by formation of various intermetallic phases. The intermetallic phases affect impact toughness and corrosion resistance significantly. Their deleterious effect on weldments has also been reviewed.

  6. The influence of sintering time on the properties of PM duplex stainless steel

    OpenAIRE

    Z. Brytan; L.A. Dobrzański; M. Actis Grande; M. Rosso

    2009-01-01

    Purpose: The purpose of this paper is to analyse the effect of sintering time on the pore morphology, microstructural changes, tensile properties and corrosion resistance of vacuum sintered duplex stainless steel.Design/methodology/approach: In presented study PM duplex stainless steels were obtained through mixing base ferritic stainless steel powder with controlled addition of elemental alloying powders and then sintered in a vacuum furnace with argon backfilling at 1250°C for different tim...

  7. Marine microbial fuel cell : use of stainless steel electrodes as anode and cathode materials

    OpenAIRE

    Dumas, Claire; Mollica, Alfonso; Féron, Damien; Basséguy, Régine; Etcheverry, Luc; Bergel, Alain

    2007-01-01

    Numerous biocorrosion studies have stated that biofilms formed in aerobic seawater induce an efficient catalysis of the oxygen reduction on stainless steels. This property was implemented here for the first time in a marine microbial fuel cell (MFC). A prototype was designed with a stainless steel anode embedded in marine sediments coupled to a stainless steel cathode in the overlying seawater. Recording current/potential curves during the progress of the experiment confirmed that the cath...

  8. Microstructure and wear resistance of spray-formed supermartensitic stainless steel

    OpenAIRE

    Guilherme Zepon; Claudio Shyinti Kiminami; Walter José Botta Filho; Claudemiro Bolfarini

    2013-01-01

    Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stai...

  9. Influence of hydrogen on corrosion and stress induced cracking of stainless steel

    OpenAIRE

    Kivisäkk, Ulf

    2010-01-01

    Hydrogen is the smallest element in the periodical table. It has been shown in several studies that hydrogen has a large influence on the corrosion and cracking behaviour of stainless steels. Hydrogen is involved in several of the most common cathode reactions during corrosion and can also cause embrittlement in many stainless steels. Some aspects of the effect of hydrogen on corrosion and hydrogen-induced stress cracking, HISC, of stainless steels were studied in this work. These aspects rel...

  10. 77 FR 16207 - Stainless Steel Bar From Brazil, India, Japan, and Spain: Final Results of the Expedited Third...

    Science.gov (United States)

    2012-03-20

    ... Steel Bar From Spain, 60 FR 11656 (March 2, 1995). The Department received a notice of intent to.... Stainless steel bar means articles of stainless steel in straight lengths that have been either hot-rolled... International Trade Administration Stainless Steel Bar From Brazil, India, Japan, and Spain: Final Results...

  11. Tensile behavior of irradiated manganese-stabilized stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    Tensile tests were conducted on seven experimental, high-manganese austenitic stainless steels after irradiation up to 44 dpa in the FFTF. An Fe-20Mn-12Cr-0.25C base composition was used, to which various combinations of Ti, W, V, B, and P were added to improve strength. Nominal amounts added were 0.1% Ti, 1% W, 0.1% V, 0.005% B, and 0.03% P. Irradiation was carried out at 420, 520, and 600{degrees}C on the steels in the solution-annealed and 20% cold-worked conditions. Tensile tests were conducted at the irradiation temperature. Results were compared with type 316 SS. Neutron irradiation hardened all of the solution-annealed steels at 420, 520, and 600{degrees}C, as measured by the increase in yield stress and ultimate tensile strength. The steel to which all five elements were added to the base composition showed the least amount of hardening. It also showed a smaller loss of ductility (uniform and total elongation) than the other steels. The total and uniform elongations of this steel after irradiation at 420{degrees}C was over four times that of the other manganese-stabilized steels and 316 SS. There was much less difference in strength and ductility at the two higher irradiation temperatures, where there was considerably less hardening, and thus, less loss of ductility. In the cold-worked condition, hardening occured only after irradiation at 420{degrees}C, and there was much less difference in the properties of the steels after irradiation. At the 420{degrees}C irradiation temperature, most of the manganese-stabilized steels maintained more ductility than the 316 SS. After irradiation at 420{degrees}C, the temperature of maximum hardening, the steel to which all five of the elements were added had the best uniform elongation.

  12. Improved corrosion resistance of 316L stainless steel by nanocrystalline and electrochemical nitridation in artificial saliva solution

    Science.gov (United States)

    Lv, Jinlong; Liang, Tongxiang

    2015-12-01

    The fluoride ion in artificial saliva significantly changed semiconductor characteristic of the passive film formed on the surface of 316L stainless steels. The electrochemical results showed that nanocrystalline α‧-martensite improved corrosion resistance of the stainless steel in a typical artificial saliva compared with coarse grained stainless steel. Moreover, comparing with nitrided coarse grained stainless steel, corrosion resistance of the nitrided nanocrystalline stainless steel was also improved significantly, even in artificial saliva solution containing fluoride ion. The present study showed that the cryogenic cold rolling and electrochemical nitridation improved corrosion resistance of 316L stainless steel for the dental application.

  13. Electrochemical and passivation behavior investigation of ferritic stainless steel in simulated concrete pore media.

    Science.gov (United States)

    Luo, Hong; Su, Huaizhi; Dong, Chaofang; Xiao, Kui; Li, Xiaogang

    2015-12-01

    The applications of stainless steel are one of the most reliable solutions in concrete structures to reduce chloride-induced corrosion problems and increase the structures service life, however, due to high prices of nickel, especially in many civil engineering projects, the austenitic stainless steel is replaced by the ferritic stainless steels. Compared with austenite stainless steel, the ferritic stainless steel is known to be extremely resistant of stress corrosion cracking and other properties. The good corrosion resistance of the stainless steel is due to the formation of passive film. While, there is little literature about the electrochemical and passive behavior of ferritic stainless steel in the concrete environments. So, here, we present the several corrosion testing methods, such as the potentiodynamic measurements, EIS and Mott-Schottky approach, and the surface analysis methods like XPS and AES to display the passivation behavior of 430 ferritic stainless steel in alkaline solution with the presence of chloride ions. These research results illustrated a simple and facile approach for studying the electrochemical and passivation behavior of stainless steel in the concrete pore environments. PMID:26501086

  14. NDE of explosion welded copper stainless steel first wall mock-up

    International Nuclear Information System (INIS)

    The study showed that reflection type C-mode scanning acoustic microscope (C-SAM) and internal ultrasonic inspection (IRIS) equipment can be applied for ultrasonic examination of copper stainless steel compound structures of ITER first wall mock-ups. Explosive welding can be applied to manufacture fully bonded copper stainless steel compound plates. However, explosives can be applied only for mechanical tightening of stainless steel cooling tubes within copper plate. If metallurgical bonding between stainless steel tubes and copper plate is required Hot Isostatic Pressing (HIP) method can be applied. (orig.)

  15. Electrochemical and passivation behavior investigation of ferritic stainless steel in simulated concrete pore media.

    Science.gov (United States)

    Luo, Hong; Su, Huaizhi; Dong, Chaofang; Xiao, Kui; Li, Xiaogang

    2015-12-01

    The applications of stainless steel are one of the most reliable solutions in concrete structures to reduce chloride-induced corrosion problems and increase the structures service life, however, due to high prices of nickel, especially in many civil engineering projects, the austenitic stainless steel is replaced by the ferritic stainless steels. Compared with austenite stainless steel, the ferritic stainless steel is known to be extremely resistant of stress corrosion cracking and other properties. The good corrosion resistance of the stainless steel is due to the formation of passive film. While, there is little literature about the electrochemical and passive behavior of ferritic stainless steel in the concrete environments. So, here, we present the several corrosion testing methods, such as the potentiodynamic measurements, EIS and Mott-Schottky approach, and the surface analysis methods like XPS and AES to display the passivation behavior of 430 ferritic stainless steel in alkaline solution with the presence of chloride ions. These research results illustrated a simple and facile approach for studying the electrochemical and passivation behavior of stainless steel in the concrete pore environments.

  16. Method for treating waste containing stainless steel

    International Nuclear Information System (INIS)

    A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe3O4. Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe2O3. Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater. 3 figs

  17. CO2 laser welding of AISI 321stainless steel

    International Nuclear Information System (INIS)

    CO2 laser welding of AISI 321austenitic stainless steel has been carried out. Bead on plate welds on 2 mm thick steel were performed with 450W CO2 laser at speeds ranging from 200 to 900 mm/min. It was observed that weld depth and width was decreased with increasing the speed at constant laser power. Butt welds on different sheet thickness of 1, 2 and 2.5 mm were performed with laser power of 450 W and at speed 750, 275 and 175 mm/min, respectively. The microstructures of the welded joints and the heat affected zones (HAZ) were examined by optical microscopy and SEM. The austenite/delta ferrite microstructure was reported in the welded zone. The microhardness and tensile strength of the welded joints were measured and found almost similar to base metal due to austenitic nature of steel

  18. The interaction between nitride uranium and stainless steel

    Science.gov (United States)

    Shornikov, D. P.; Nikitin, S. N.; Tarasov, B. A.; Baranov, V. G.; Yurlova, M. S.

    2016-04-01

    Uranium nitride is most popular nuclear fuel for Fast Breeder Reactor New Generation. In-pile experiments at reactor BOR-60 was shown an interaction between nitride fuel and stainless steel in the range of 8-11% burn up (HA). In order to investigate this interaction has been done diffusion tests of 200 h and has been shown that the reaction occurs in the temperature range 1000-1100 ° C. UN interacted with steel in case of high pollution oxygen (1000-2000 ppm). Also has been shown to increase interaction UN with EP-823 steel in the presence of cesium. In this case the interaction layer had a thickness about 2-3 μm. Has been shown minimal interaction with new ODS steel EP-450. The interaction layer had a thickness less then 2 μm. Did not reveal the influence of tellurium and iodine increased interaction. It was show compatibility at 1000 °C between UN and EP-450 ODS steel, chrome steel, alloying aluminium and silicium.

  19. Wear behavior of high velocity arc sprayed 3Cr13 steel coating in oil containing sand

    Institute of Scientific and Technical Information of China (English)

    DU Ling-zhong; XU Bin-shi; DONG Shi-yun; YANG Hua; WU Yi-xiong

    2004-01-01

    To improve the wear resistance of the machine components serving in desert areas, the 3Cr13 stainless steel coating was produced by the high velocity arc spraying technique. The microstructure and phase constitute of the coating were analyzed by SEM and XRD. The effects of sand content on the friction and wear behaviors of the coating under the lubrication of oil containing sand were investigated on a ball-on-disk tester. SEM was used to reveal the wear mechanisms of the coating. The results show that the wear volume increases with increasing the sand content in the oil, and the sprayed coating exhibits better triobological properties compared with the 1045 steel. The predominant wear mechanisms of the sprayed coating are micro-cutting, brittle fracture and delamination.

  20. Fabrication of high nitrogen austenitic stainless steels with excellent mechanical and pitting corrosion properties

    Institute of Scientific and Technical Information of China (English)

    Hua-bing Li; Zhou-hua Jiang; Yang Cao; Zu-rui Zhang

    2009-01-01

    18Cr18Mn2Mo0.9N high nitrogen austenitic stainless steel exhibits high strength and good ductility at room temperature. The steel shows typical duc-tile-brittle transition behavior and excellent pitting corrosion resistance properties.

  1. The influence of cold work on the oxidation behaviour of stainless steel

    International Nuclear Information System (INIS)

    In this thesis the study of the interaction of oxygen gas with stainless steel surfaces is described. Thermogravimetry, microscopy and ellipsometry have been used to follow the oxidation in situ, while EDX, AES and XPS have been used to determine the oxide compositions. The aim of this thesis is to reveal the influence on the oxidation behaviour of stainless steel of i) cold work (rolling, drawing, milling, polishing and Ar ion bombardment) ii) the initially formed oxide and iii) the experimental conditions. Two types of stainless steels have been used (AISI 304 (a 18/8 Cr/Ni steel) and Incoloy 800 H (a 20/30 Cr/Ni steel)). (Auth.)

  2. X-Ray diffraction technique applied to study of residual stresses after welding of duplex stainless steel plates

    Energy Technology Data Exchange (ETDEWEB)

    Monin, Vladimir Ivanovitch; Assis, Joaquim Teixeira de [Instituto Politecnico do Rio e Janeiro (IPRJ), Nova Friburgo, RJ (Brazil); Lopes, Ricardo Tadeu; Turibus, Sergio Noleto; Payao Filho, Joao C., E-mail: sturibus@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2014-08-15

    Duplex stainless steel is an example of composite material with approximately equal amounts of austenite and ferrite phases. Difference of physical and mechanical properties of component is additional factor that contributes appearance of residual stresses after welding of duplex steel plates. Measurements of stress distributions in weld region were made by X-ray diffraction method both in ferrite and austenite phases. Duplex Steel plates were joined by GTAW (Gas Tungsten Arc Welding) technology. There were studied longitudinal and transverse stress components in welded butt joint, in heat affected zone (HAZ) and in points of base metal 10 mm from the weld. Residual stresses measured in duplex steel plates jointed by welding are caused by temperature gradients between weld zone and base metal and by difference of thermal expansion coefficients of ferrite and austenite phases. Proposed analytical model allows evaluating of residual stress distribution over the cross section in the weld region. (author)

  3. In situ 3D monitoring of corrosion on carbon steel and ferritic stainless steel embedded in cement paste

    KAUST Repository

    Itty, Pierre-Adrien

    2014-06-01

    In a X-ray microcomputed tomography study, active corrosion was induced by galvanostatically corroding steel embedded in cement paste. The results give insight into corrosion product build up, crack formation, leaching of products into the cracks and voids, and differences in morphology of corrosion attack in the case of carbon steel or stainless steel reinforcement. Carbon steel was homogeneously etched away with a homogeneous layer of corrosion products forming at the steel/cement paste interface. For ferritic stainless steel, pits were forming, concentrating the corrosion products locally, which led to more extensive damage on the cement paste cover. © 2014 Elsevier Ltd.

  4. Effect of Deleterious Phases on Corrosion Resistance of Duplex Stainless Steel (2205)

    OpenAIRE

    AbdulKadar M. Godil; Hitesh A. Narsia; M. N. Patel; Mr. Paresh U. Haribhakti

    2013-01-01

    Duplex stainless steel is a Ferritic(BCC)-Austenitic(FCC) steel, covers the advantages of both Austenitic and Ferritic Stainless steels. They having good mechanical and corrosion resistance properties are widely used in many industries like chemical plants, refineries for critical equipments such as pressure vessels, heatexchangers, water heaters. Major problem occurs with duplex steels when they are worked or heated above about temperature of 280°C. Detrimental phases like Sigma, Chi, Laves ...

  5. Threshold Chloride Concentration of Stainless Steels in Simulated Concrete Pore Solution

    OpenAIRE

    Wang, Hailong; Ling, Jiayan; Sun, Xiaoyan

    2016-01-01

    To evaluate whether stainless steel can replace carbon steel as rebar in reinforced concrete structures exposed to aggressive environment, the threshold chloride concentration of carbon steel, austenitic and duplex stainless steels were experimentally studied in this paper. The solutions with pH ranging from 9.5 to 13.6 were used herein to simulate the pore liquids in both alkaline and carbonated concretes. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests we...

  6. Separation by transportation in vapor phase of stainless steels components

    International Nuclear Information System (INIS)

    A procedure for separating cobalt from other constituents of radioactive stainless steel is proposed in order to condition material originating from dismantling of reactor pressure vessels. The procedure is based on the transport in the vapour phase, under the presence of an appropriate carrier gas and a thermal gradient in a sealed device. By calculation, iodine was found to be the most appropriate carrier gas. Tests carried out at 50 mg to 2 g scale in quartz ampoules permitted to determine parameters, i.e. temperature range and gradient, pressure, and the effectiveness. It was shown that steel turnings may be treated efficiently. The procedure achieves well a partition of stainless steel into two metal masses: one containing the bulk of cobalt and radioactivity, the other depleted of cobalt and suitable for recycling. There is few or no secondary waste created, but the costs of the procedure are estimated to be high, i.e. between 100 and 1,000 ECU/kg

  7. Stable phases in aged type 321 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, J.; Leitnaker, J.M.

    1978-01-01

    X-ray diffraction and Analytical Electron Microscopy have been used to characterize the precipitate phases present in type 321 stainless steel after 17 years of service at approximately 600/sup 0/C. The morphology, crystallography, and orientation relationships with the matrix of the precipitates have been determined along with the chemical composition of several of the phases. Long-term aging of type 321 stainless steel indicates TiC, not M/sub 23/C/sub 6/, is the stable carbide phase. A theory is developed to explain appearance of M/sub 23/C/sub 6/ at intermediate times. The theory also indicates the means for preventing M/sub 23/C/sub 6/ formation and hence sensitization of the steel to intergranular corrosion. The amount of sigma found correlates well with results from shorter time studies. Ti/sub 4/C/sub 2/S/sub 2/ and a complex phosphide-arsenide were also present.

  8. High-pressure stainless steel active membrane microvalves

    Science.gov (United States)

    Sharma, G.; Svensson, S.; Ogden, S.; Klintberg, L.; Hjort, K.

    2011-07-01

    In this work, high-pressure membrane microvalves have been designed, manufactured and evaluated. The valves were able to withstand back-pressures of 200 bar with a response time of less than 0.6 s. These stainless steel valves, manufactured with back-end batch production, utilize the large volume expansion coupled to the solid-liquid phase transition in paraffin wax. When membrane materials were evaluated, parylene coated stainless steel was found to be the best choice as compared to polydimethylsiloxane and polyimide. Also, the influence of the orifice placement and diameter is included in this work. If the orifice is placed too close to the rim of the membrane, the valve can stay sealed even after turning the power off, and the valve will not open until the pressure in the system is released. The developed steel valves, evaluated for both water and air, provide excellent properties in terms of mechanical stability, ease of fabrication, and low cost. Possible applications include sampling at high pressures, chemical microreactors, high performance liquid chromatography, pneumatics, and hydraulics.

  9. Malfunction analysis of OPGW of stainless steel-unit structure

    Institute of Scientific and Technical Information of China (English)

    李星梅; 张素芳; 王旭锋; 乞建勋

    2008-01-01

    Composite fiber optic overhead ground wire (OPGW) is increasingly applied in China’s overhead transmission lines. The stainless steel structure is adopted by most OPGWs as it is very small and easy to match the existing ground wire. The malfunction of OPGW in Beijing-Shanghai Optical Communication Project was analyzed through the chemical composition method and spectrum semi-quantitative method. The analysis indicates that the cable fault was due to the failure of seepage and irregular holes in the steel pipe of the optical unit. The rain water and the watery air entered into the optical units, and the water in turn became ice when temperature dropped. The occurrence of ice led to the acceleration of attenuation of the fiber. The results show that the rupture of stainless steel tube is mainly due to the instability of welding technique. The malfunction of OPGW is due to the local defects of welding seam because of local stress concentration in the manufacturing process.

  10. Sensitization of Laser-beam Welded Martensitic Stainless Steels

    Science.gov (United States)

    Dahmen, Martin; Rajendran, Kousika Dhasanur; Lindner, Stefan

    Ferritic and martensitic stainless steels are an attractive alternative in vehicle production due to their inherent corrosion resistance. By the opportunity of press hardening, their strength can be increased to up to 2000 MPa, making them competitors for unalloyed ultra-high strength steels. Welding, nevertheless, requires special care, especially when it comes to joining of high strength heat treated materials. With an adopted in-line heat treatment of the welds in as-rolled as well as press hardened condition, materials with sufficient fatigue strength and acceptable structural behavior can be produced. Because of microstructural transformations in the base material such as grain coarsening and forced carbide precipitation, the corrosion resistance of the weld zone may be locally impaired. Typically the material in the heat-affected zone becomes sensitive to intergranular cracking in the form of knife-edge corrosion besides the fusion line. The current study comprises of two text scenarios. By an alternating climate test, general response in a corroding environment is screened. In order to understand the corrosion mechanisms and to localize the sensitive zones, sensitisation tests were undertaken. Furthermore, the applicability of a standard test according to ASTM 763-83 was examined. It was found that the alternative climate test does not reveal any corrosion effects. Testing by the oxalic acid test revealed clearly the effect of welding, weld heat treatment and state of thermal processing. Also application of the standard which originally suited for testing ferritic stainless steels could have been justified.

  11. Cold Spray Repair of Martensitic Stainless Steel Components

    Science.gov (United States)

    Faccoli, M.; Cornacchia, G.; Maestrini, D.; Marconi, G. P.; Roberti, R.

    2014-12-01

    The possibility of using cold spray as repair technique of martensitic stainless steel components was evaluated through laboratory investigations. An austenitic stainless steel feedstock powder was chosen, instead of soft metals powders like nickel, copper, or aluminum, used for repairing components made in light alloy or cast iron. The present study directly compares the microstructure, the residual stresses, and the micro-hardness of repairs obtained by cold spray and by TIG welding, that is commonly used as repair technique in large steel components. XRD and optical metallographic analysis of the repairs showed that cold spray offers some advantages, inducing compressive residual stresses in the repair and avoiding alterations of the interface between repair and base material. For these reasons, a heat treatment after the cold spray repair is not required to restore the base material properties, whereas a post-weld heat treatment is needed after the welding repair. Cold spray repair also exhibits a higher micro-hardness than the welding repair. In addition, the cavitation erosion resistance of a cold spray coating was investigated through ultrasonic cavitation tests, and the samples worn surfaces were observed by scanning electron microscopy.

  12. THE EFFECT OF W ON THE REPASSIVATION BEHAVIOR OF Ni-ADDED STAINLESS STEELS

    Institute of Scientific and Technical Information of China (English)

    J.X. Pan; K. Y. Kim

    2005-01-01

    The effect of W on the repassivation behavior of Ni-added stainless steels was investigated with respect to the repassivation rate and the SCC susceptibility. It was found that more stable passive film was formed on the W-modified stainless steels than that of steels without W-modification, and the repassivation rate was faster for W-modified stainless steels in acidic chloride solution (0.5M H2SO4+3.5% Cl-). In neutral chloride solution (1M MgCl2), there were no significant differences on both passivation properties and the repassivation rates for duplex stainless steels,while W-modified austenite stainless steel showed faster repassivation rate. The SCC tests verified that W-modified Ni-added stainless steels exhibited better SCC resistance than steels without W in chloride solution. Moreover, W-modification in higher Ni-added stainless steels exhibited more remarkable SCC resistance than steels with lower Ni content in chloride solution.

  13. Degradation of mechanical properties of stainless steel cladding due to neutron irradiation and thermal aging

    International Nuclear Information System (INIS)

    Thermal aging of three-wire series-arc stainless steel weld overlay cladding at 288 degrees C for 1605 h resulted in an appreciable decrease (16%) in the Charpy V-notch (CVN) upper-shelf energy (USE), but the effect on the 41-J transition temperature shift was very small (3 degrees C). The combined effect following neutron irradiation at 288 degrees C to a fluence of 5 X 1019 neutrons/cm2 (>1 MeV) was a 22% reduction in the USE and a 29 degrees C shift in the 41-J transition temperature. The effect of thermal aging on tensile properties was very small. However, the combined effect of irradiation and aging was an increase in the yield strength (6 to 34% at test temperatures from 288 to -125 degrees C) and no apparent change in ultimate tensile strength or total elongation. Neutron irradiation reduced the initiation fracture toughness (Jκ) much more than did thermal aging alone. However, irradiation slightly decreased the tearing modulus but no reduction was caused by thermal aging alone. The effects of long-term thermal exposure times (20,000 and 50,000 h) will be investigated when the specimens become available. Also, long-term thermal exposure of the three-wire cladding as well as type 308 stainless steel weld materials at 343 degrees C is in progress

  14. Predicting the toughness of SMA austenitic stainless steel welds at 77 K

    International Nuclear Information System (INIS)

    Austenitic stainless steels often provide the best combination of strength and toughness for cryogenic applications: however, the weld toughness is frequently much lower than that of the base metal. This study proposes a more accurate and simpler model for developing improved filler metal compositions. Several previous studies of the weld toughness were analyzed separately and in combination using a stepwise regression method and an expanded variable list. The total data base consisted of chemical composition, ferrite number (FN), and the Charpy V-notch (CVN) toughness at 77 K of 79 austenitic stainless steel welds deposited by the shielded metal arc process. Analysis of the complete data base revealed that the FN calculated from the Schaeffler diagram was the most significant variable for predicting the CVN toughness. The predictive equation produced a better correlation between the measured and predicted values of weld toughness than the previously published predictive equations. The group of 36 fully austenitic welds and the group of 21 type 316 welds in the data base were analyzed by the same procedure. In both cases the ferrite number was found to be the most significant predictor of toughness

  15. Influence of PWHT on Toughness of High Chromium and Nickel Containing Martensitic Stainless Steel Weld Metals

    Science.gov (United States)

    Divya, M.; Das, Chitta Ranjan; Mahadevan, S.; Albert, S. K.; Pandian, R.; Kar, Sujoy Kumar; Bhaduri, A. K.; Jayakumar, T.

    2015-06-01

    Commonly used 12.5Cr-5Ni consumable specified for welding of martensitic stainless steels is compared with newly designed 14.5Cr-5Ni consumable in terms of their suitability for repair welding of 410 and 414 stainless steels by gas tungsten arc welding process. Changes in microstructure and austenite evolution were investigated using optical, scanning electron microscopy, X-ray diffraction techniques and Thermo-Calc studies. Microstructure of as-welded 12.5Cr-5Ni weld metal revealed only lath martensite, whereas as-welded 14.5Cr-5Ni weld metal revealed delta-ferrite, retained austenite, and lath martensite. Toughness value of as-welded 12.5Cr-5Ni weld metal is found to be significantly higher (216 J) than that of the 14.5Cr-5Ni weld metal (15 J). The welds were subjected to different PWHTs: one at 923 K (650 °C) for 1, 2, 4 hours (single-stage PWHT) and another one at 923 K (650 °C)/4 h followed by 873 K (600 °C)/2 h or 873 K (600 °C)/4 h (two-stage heat treatment). Hardness and impact toughness of the weld metals were measured for these weld metals and correlated with the microstructure. The study demonstrates the importance of avoiding formation of delta-ferrite in the weld metal.

  16. Influence of surface finish on the cleanability of stainless steel.

    Science.gov (United States)

    Frank, J F; Chmielewski, R

    2001-08-01

    Stainless steel for fabricating food processing equipment is available with various surface finishes. The objective of this research was to determine the effect of surface finish on cleanability. Nine samples of stainless steel, type 304, from various manufacturers including no finish (hot rolled and pickled), #4 finish, 2B mechanical polished, and electropolished were tested. Cleanability was assessed by using coupon samples soiled with either cultured milk inoculated with spores of Bacillus stearothermophilus or by growth of a Pseudomonas sp. biofilm. Samples were cleaned by immersion in a turbulent bath of 1.28% sodium hydroxide at 66 degrees C for 3 min followed by a sterile water rinse, neutralizing in 0.1% phosphoric acid for 30 s, rinsing in phosphate buffer, sanitizing in 100 ppm hypochlorite, neutralizing in sodium thiosulfate, and drying. To determine residual milk soil, coupon samples were covered with PM indicator agar and incubated for 25 h at 58 degrees C. Other coupons were subjected to an additional 10 soiling or cleaning cycles, and the residual protein was measured by using epifluorescent microscopy and image analysis. Results indicate that the spore count was more precise for measuring initial cleanability of the finished samples, and the protein residue determination was useful for determining the effect of repeated cleaning. Data on the removal of milk soil suggest that stainless steel should be purchased based on measures of surface defects rather than finish type. Surface defects, as determined using a surface roughness gauge, produced a correlation of 0.82 with spore counts. Data also indicated that biofilm was more difficult to remove than milk-based soil. PMID:11510656

  17. Aging and Embrittlement of High Fluence Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Was, gary; Jiao, Zhijie; der ven, Anton Van; Bruemmer, Stephen; Edwards, Dan

    2012-12-31

    Irradiation of austenitic stainless steels results in the formation of dislocation loops, stacking fault tetrahedral, Ni-Si clusters and radiation-induced segregation (RIS). Of these features, it is the formation of precipitates which is most likely to impact the mechanical integrity at high dose. Unlike dislocation loops and RIS, precipitates exhibit an incubation period that can extend from 10 to 46 dpa, above which the cluster composition changes and a separate phase, (G-phase) forms. Both neutron and heavy ion irradiation showed that these clusters develop slowly and continue to evolve beyond 100 dpa. Overall, this work shows that the irradiated microstructure features produced by heavy ion irradiation are remarkably comparable in nature to those produced by neutron irradiation at much lower dose rates. The use of a temperature shift to account for the higher damage rate in heavy ion irradiation results in a fairly good match in the dislocation loop microstructure and the precipitate microstructure in austenitic stainless steels. Both irradiations also show segregation of the same elements and in the same directions, but to achieve comparable magnitudes, heavy ion irradiation must be conducted at a much higher temperature than that which produces a match with loops and precipitates. First-principles modeling has confirmed that the formation of Ni-Si precipitates under irradiation is likely caused by supersaturation of solute to defect sinks caused by highly correlated diffusion of Ni and Si. Thus, the formation and evolution of Ni-Si precipitates at high dose in austenitic stainless steels containing Si is inevitable.

  18. Chromium-nickel stainless steel and method of its manufacture

    International Nuclear Information System (INIS)

    The chromium-nickel stainless steel is designed for the production of rolled bands to be welded onto the primary circuit component surfaces. The invention claims the steel composition. Phosphorus content is restricted to an amount of 0.005 to 0.025%, sulfur to 0.001 to 0.012%, oxygen to 0.001 to 0.008% aluminium to 0.005 to 0.05%, and titanium to 0.02 to 0.20%. The steel may also contain 0.01 to 0.15% of cerium, 0.01 to 0.15% of zirconium and 0.0001 to 0.005% of boron while the overall combined content of cerium, zirconium and boron does not exceed 0.25%. The initial material is nonalloyed waste, nickel metal and ferroalloys. The steel is deoxidized with aluminium and its chemical composition is adjusted with an addition of ferrochrome or nickel. The steel is then vacuum processed and after standing, it is cast at a temperature of 1520 to 1580 degC. (J.P.)

  19. Joining dissimilar stainless steels for pressure vessel components

    Science.gov (United States)

    Sun, Zheng; Han, Huai-Yue

    1994-03-01

    A series of studies was carried out to examine the weldability and properties of dissimilar steel joints between martensitic and austenitic stainless steels - F6NM (OCr13Ni4Mo) and AISI 347, respectively. Such joints are important parts in, e.g. the primary circuit of a pressurized water reactor (PWR). This kind of joint requires both good mechanical properties, corrosion resistance and a stable magnetic permeability besides good weldability. The weldability tests included weld thermal simulation of the martensitic steel for investigating the influence of weld thermal cycles and post-weld heat treatment (PWHT) on the mechanical properties of the heat-affected zone (HAZ); implant testing for examining the tendency for cold cracking of martensitic steel; rigid restraint testing for determining hot crack susceptibility of the multi-pass dissimilar steel joints. The joints were subjected to various mechanical tests including a tensile test, bending test and impact test at various temperatures, as well as slow strain-rate test for examining the stress corrosion cracking tendency in the simulated environment of a primary circuit of a PWR. The results of various tests indicated that the quality of the tube/tube joints is satisfactory for meeting all the design requirements.

  20. Thermal stability of ultrafine-grained austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Etienne, A.; Radiguet, B.; Genevois, C.; Le Breton, J.-M. [Groupe de Physique des Materiaux, Universite et INSA de Rouen, UMR CNRS 6634, BP 12, 76 801 Saint Etienne du Rouvray Cedex (France); Valiev, R. [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12K. Marx Street, 450000 Ufa (Russian Federation); Pareige, P., E-mail: philippe.pareige@univ-rouen.fr [Groupe de Physique des Materiaux, Universite et INSA de Rouen, UMR CNRS 6634, BP 12, 76 801 Saint Etienne du Rouvray Cedex (France)

    2010-08-20

    Ultrafine-grained 316 and 304 austenitic stainless steel samples have been produced by high pressure torsion. Their microstructure, after deformation and annealing at a temperature in the 350-900 deg. C range, has been characterized using several techniques (transmission electron microscopy, X-ray diffraction, Moessbauer spectroscopy). The average grain size in the ultrafine-grained 316 is about 40 nm while it is larger in the ultrafine-grained 304 due to a smaller deformation. Results show the formation of {alpha}'-martensite during deformation in both steels while {epsilon}-martensite is formed only in the 304 steel. Annealing at 350 deg. C induces the decrease of {alpha}'-martensite content in the 316 steel. The trend is different in the 304 steel, in which the {alpha}'-martensite content increases. Recrystallization of grains is observed from 700 deg. C. Moessbauer spectroscopy shows a reduction of the level of solute atoms in {alpha}'-martensite during annealing.

  1. Microbial corrosion in weld zone of stainless steel. Stainless ko yosetsubu no biseibutsu fushoku

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, E. (National Chemical Laboratory for Industry, Tsukuba (Japan)); Nishimura, M. (Mitsubishi Kakoki Kaisha, Ltd., Tokyo (Japan))

    1992-10-15

    Microbial corrosion may happen wherever water is treated in many kinds of practical metal except titan, such as common steel, copper alloy, stainless steel, and high-nickel alloy. Although microbes causing microbial corrosion are not limited to specified microbes, specially affecting microbes are iron bacteria, iron-oxidizing bacteria, and sulfate-reducing bacteria. mechanism in these microbial corrosion, which is fundamentally caused through formation of oxygen concentration cells and production of metabolites, is complex and different by each microbe. In the case of stainless steel, the corrosion is located mainly in weld zones or heat affected zones, the shape of corrosion is like a pot, and the pattern is a type of pitting corrosion. Microbes are apt to adhere to the surface near weld zones, then oxygen becomes consequently insufficient beneath the surface, where the self-mending capacity of passive films is deprived, resulting in occurrence of pitting corrosion. For protection of microbial corrosion, it is essential to control water so that habitation of microbes is not formed. 9 refs., 3 figs.

  2. Characteristics of residual stresses of water jet peened stainless steel

    International Nuclear Information System (INIS)

    The material of the specimen was austenitic stainless steel, SUS316L. The residual stresses in the specimen was introduced by a water jet peening (WJP). The change in the residual stress with thermal aging at 773K was measured by an X-ray stress measurement. The WJP residual stresses were an equi-biaxial stress state, and the compressive residual stress did not decrease against the thermal aging. To investigate dependence of the residual stress on a lattice plane, the WJP residual stresses were measured using hard synchrotron X-rays. (author)

  3. Thermal aging evaluation of casting stainless steel under BWR environment

    International Nuclear Information System (INIS)

    Effect of thermal aging under BWR condition on material properties of casting stainless steel were evaluated by such as Charpy impact test, using replaced BWR component material. Solution heat treatment was performed to the same material and the material properties were obtained. Comparing each material test results, impact value of thermal aging material was lower than solution heat treatment material. By the results, thermal aging effect on material properties under BWR condition was confirmed. The material properties were compared with model equation using PLM evaluation and conservativeness of model equation was confirmed. (author)

  4. Analysis of ridging in ferritic stainless steel sheet

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P.D. [Novelis Inc., Novelis Global Technology Centre, 945 Princess Street, Kingston, Ont., K7L 5L9 (Canada)]. E-mail: wupeidong@hotmail.com; Jin, H. [Novelis Inc., Novelis Global Technology Centre, 945 Princess Street, Kingston, Ont., K7L 5L9 (Canada); Shi, Y. [Novelis Inc., Novelis Global Technology Centre, 945 Princess Street, Kingston, Ont., K7L 5L9 (Canada); Lloyd, D.J. [Novelis Inc., Novelis Global Technology Centre, 945 Princess Street, Kingston, Ont., K7L 5L9 (Canada)

    2006-05-15

    The finite element method is used to numerically simulate the development of ridging/roping in ferritic stainless steel sheet under stretching. The measured electron backscattered diffraction (EBSD) data (grain orientations and their spatial distributions) are directly incorporated into the finite element model and the constitutive response at an integration point is described by the single crystal plasticity theory. The effects of spatial orientation distribution, imposed deformation path, and inhomogeneous deformation within individual grains on the roping are discussed. It is found that the initial texture and its spatial distribution are the predominant factors for the development of ridging.

  5. Low temperature gaseous nitriding and carburising of stainless steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A.J.

    2005-01-01

    The response of various austenitic and duplex stainless steel grades to low temperature gaseous nitriding and carburising was investigated. Gaseous nitriding was performed in ammonia/hydrogen mixtures at temperatures ,723 K; gaseous carburising was carried out in carbon monoxide/hydrogen mixtures...... for temperatures (783 K. The case developed by thermochemical treatment was examined using reflected light microscopy, X-ray diffraction analysis and microhardness testing. Both nitriding and carburising led to the development of expanded austenite in the surface adjacent zone, irrespective of the phase...... constitution of the substrate. A two step process, consisting of carburising followed by nitriding, provides great flexibility with regard to adjusting the hardness–depth profile....

  6. Femtosecond laser color marking stainless steel surface with different wavelengths

    Science.gov (United States)

    Li, Guoqiang; Li, Jiawen; Hu, Yanlei; Zhang, Chenchu; Li, Xiaohong; Chu, Jiaru; Huang, Wenhao

    2015-03-01

    The femtosecond laser color marking stainless steel surfaces with different incident wavelengths were investigated theoretically and experimentally. It indicates that the spectral regions of the colors firstly increase and then reduce with increasing spatial periods of the ripples induced by laser irradiation. Additionally, the colors are gradually changed from blue to red due to the elongation of the diffracted light wavelengths. As a result, the color effects are distinctly different. This study offers a new controllable parameter to produce diverse colors, which may find a wide range of applications in the laser color marking, art designing and so on.

  7. Laser-induced color marking of stainless steel

    Science.gov (United States)

    Antonczak, Arkadiusz J.; Nowak, Maciej; Koziol, Pawel; Kaczmarek, Pawel R.; Waz, Adam T.; Abramski, Krzysztof M.

    2013-01-01

    This paper presents the analysis of the impact of selected process parameters on the resulting laser color marking. The study was conducted for AISI 304 multipurpose stainless steel using a commercially available industrial fiber laser. It was determined how various process parameters, such as laser power, scanning speed of the laser beam, temperature of the material, location of the sample relative to the focal plane, affect the repeatability of the colors obtained. For objective assessment of color changes, an optical spectrometer and the CIE color difference parameter ΔEab * were used.

  8. General and Localized Corrosion of Borated Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    T.E. Lister; Ronald E. Mizia; A.W. Erickson; T.L. Trowbridge; B. S. Matteson

    2008-03-01

    The Transportation, Aging and Disposal (TAD) canister-based system is being proposed to transport and store spent nuclear fuel at the Monitored Geologic Repository (MGR) located at Yucca Mountain, Nevada. The preliminary design of this system identifies borated stainless steel as the neutron absorber material that will be used to fabricate fuel basket inserts for nuclear criticality control. This paper discusses corrosion test results for verifying the performance of this material manufactured to the requirements of ASTM A887, Grade A, under the expected repository conditions.

  9. NARROW GAP LASER WELDING OF THICK SECTION STAINLESS STEEL

    OpenAIRE

    2012-01-01

    Laser welding of metals typically has a weld penetration of 1-2 mm/kW laser power. Therefore laser welding of thick section materials would require very high power lasers. In this paper we report an investigation into multi-pass laser welding of 316L stainless steel sheets of 5-10 mm thickness, based on narrow gap (1.5 mm) approach using a 1 kW single mode fibre laser. A filler wire of 316L with a 0.8 mm diameter was used in the welding process. The integrity of the weld, microstructure and h...

  10. 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.

  11. Laser Welding of Large Scale Stainless Steel Aircraft Structures

    Science.gov (United States)

    Reitemeyer, D.; Schultz, V.; Syassen, F.; Seefeld, T.; Vollertsen, F.

    In this paper a welding process for large scale stainless steel structures is presented. The process was developed according to the requirements of an aircraft application. Therefore, stringers are welded on a skin sheet in a t-joint configuration. The 0.6 mm thickness parts are welded with a thin disc laser, seam length up to 1920 mm are demonstrated. The welding process causes angular distortions of the skin sheet which are compensated by a subsequent laser straightening process. Based on a model straightening process parameters matching the induced welding distortion are predicted. The process combination is successfully applied to stringer stiffened specimens.

  12. Stainless steel clad for light water reactor fuels. Final report

    International Nuclear Information System (INIS)

    Proper reactor operation and design guidelines are necessary to assure fuel integrity. The occurrence of fuel rod failures for operation in compliance with existing guidelines suggests the need for more adequate or applicable operation/design criteria. The intent of this study is to develop such criteria for light water reactor fuel rods with stainless steel clad and to indicate the nature of uncertainties in its development. The performance areas investigated herein are: long term creepdown and fuel swelling effects on clad dimensional changes and on proximity to clad failure; and short term clad failure possibilities during up-power ramps

  13. Oxidation resistant high creep strength austenitic stainless steel

    Science.gov (United States)

    Brady, Michael P.; Pint, Bruce A.; Liu, Chain-Tsuan; Maziasz, Philip J.; Yamamoto, Yukinori; Lu, Zhao P.

    2010-06-29

    An austenitic stainless steel displaying high temperature oxidation and creep resistance has a composition that includes in weight percent 15 to 21 Ni, 10 to 15 Cr, 2 to 3.5 Al, 0.1 to 1 Nb, and 0.05 to 0.15 C, and that is free of or has very low levels of N, Ti and V. The alloy forms an external continuous alumina protective scale to provide a high oxidation resistance at temperatures of 700 to 800.degree. C. and forms NbC nanocarbides and a stable essentially single phase fcc austenitic matrix microstructure to give high strength and high creep resistance at these temperatures.

  14. Shrinkage Prediction for the Investment Casting of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL

    2007-01-01

    In this study, the alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. Dimensions of the die tooling, wax pattern, and casting were measured using a Coordinate Measurement Machine in order to obtain the actual tooling allowances. The alloy dimensions were obtained from numerical simulation results of solidification, heat transfer, and deformation phenomena. The numerical simulation results for the shrinkage factors were compared with experimental results.

  15. Hardening of aged duplex stainless steels by spinodal decomposition.

    Science.gov (United States)

    Danoix, F; Auger, P; Blavette, D

    2004-06-01

    Mechanical properties, such as hardness and impact toughness, of ferrite-containing stainless steels are greatly affected by long-term aging at intermediate temperatures. It is known that the alpha-alpha' spinodal decomposition occurring in the iron-chromium-based ferrite is responsible for this aging susceptibility. This decomposition can be characterized unambiguously by atom probe analysis, allowing comparison both with the existing theories of spinodal decomposition and the evolution of some mechanical properties. It is then possible to predict the evolution of hardness of industrial components during service, based on the detailed knowledge of the involved aging process. PMID:15233853

  16. Dependence of Radiation Damage in Stainless Steel on Irradiation Dose

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The accelerator driven radioactive clean nuclear power system (ADS) is a novel innovative idea forthe sustainable development of nuclear power system. The spallation neutron source system is one of thethree key parts of ADS, which provides source neutrons of about 1018 s-1 for the burning-up of fuels.Stainless steel (SS) is used for the beam window and target materials of the spallation neutron sourcesystem. It is irradiated by high-energy and intense protons and/or neutrons during operation. Theaccumulated displacement damage dose could reach a couple of hundred dpa (displacement per atom) per

  17. Fiber-laser welding for ultra-high tensile strength steel and stainless steel

    International Nuclear Information System (INIS)

    Ultra-high tensile strength steel of 980 or 1150 MPa class has been often used for a large scale construction machine with lightweight parts because of transport weight limit. This steel needs its pre-processing before welding and has a tendency of delayed cracking, that requests a high welding technique with qualified welders. Austenitic stainless steel frequency used for nuclear energy related equipments has much strains caused by welding because of a large coefficient of thermal expansion. As a welding with small amount of its heat input and without a large size facility like a vacuum chamber, a fiber-laser welding was chosen to apply to equipments made of ultra-high tensile strength steel and stainless steel. Tensile and bending tests for I-butt and around 2mm root gap welded joints of high strength steel of 980 MPa showed their mechanical properties were similar to those of base metal. I-butt welded joints of high strength steel of 1150 MPa showed similar mechanical properties of base metal but as for root gap welded joint, a filler metal was not available. With filler metal of 980 MPa instead, the welded joints showed similar tensile strength of base metal but a crack occurred at the bending test according to the JIS welding procedure qualification specification. Application of fiber laser welding to stainless steel had been conducted successfully for I-butt welded joints of good penetration up to the plate thickness of 8mm. As an example, T-joint of mercury target vessel for J-PARC was produced by fiber laser welding, that became to apply to other nuclear equipments. (T. Tanaka)

  18. 78 FR 45271 - Welded Stainless Steel Pressure Pipe From Malaysia, Thailand, and Vietnam

    Science.gov (United States)

    2013-07-26

    ... Commission, Washington, DC, and by publishing the notice in the Federal Register of May 24, 2013 (78 FR 31574... COMMISSION Welded Stainless Steel Pressure Pipe From Malaysia, Thailand, and Vietnam Determination On the... injured by reason of imports from Malaysia, Thailand, and Vietnam of welded stainless steel pressure...

  19. Male-mediated spontaneous abortion among spouses of stainless steel welders

    DEFF Research Database (Denmark)

    Hjollund, N H; Bonde, Jens Peter; Jensen, Tina Kold;

    2000-01-01

    Male-mediated spontaneous abortion has never been documented for humans. The welding of stainless steel is associated with the pulmonary absorption of hexavalent chromium, which has genotoxic effects on germ cells in rodents. Clinical and early subclinical spontaneous abortions were examined among...... spouses of stainless-steel welders....

  20. 75 FR 76025 - Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan

    Science.gov (United States)

    2010-12-07

    ... party responded to the sunset review notice of initiation by the applicable deadline * * *'' (75 FR... COMMISSION Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan AGENCY: United States... stainless steel butt-weld pipe fittings from Japan, Korea, and Taiwan would be likely to lead...

  1. 75 FR 59744 - Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan

    Science.gov (United States)

    2010-09-28

    ... group response to its notice of institution (75 FR 30437, June 1, 2010) was adequate and that the... COMMISSION Stainless Steel Sheet and Strip From Germany, Italy, Japan, Korea, Mexico, and Taiwan AGENCY... Korea and the antidumping duty orders on stainless steel sheet and strip from Germany, Italy,...

  2. 75 FR 53714 - Stainless Steel Butt-Weld Pipe Fittings From Japan, Korea, and Taiwan

    Science.gov (United States)

    2010-09-01

    ... imports of stainless steel butt-weld pipe fittings from Japan (53 FR 9787). On February 23, 1993, Commerce... on imports of stainless steel butt-weld pipe fittings from Japan, Korea, and Taiwan (65 FR 11766... Japan, Korea, and Taiwan (70 FR 61119). The Commission is now conducting third reviews to...

  3. 77 FR 41969 - Stainless Steel Bar From Japan: Rescission of Antidumping Duty Administrative Review

    Science.gov (United States)

    2012-07-17

    ... Revocation in Part, and Deferral of Administrative Review, 77 FR 19179, 19181 (March 30, 2012). Based on a... International Trade Administration Stainless Steel Bar From Japan: Rescission of Antidumping Duty Administrative...) initiated an administrative review of the antidumping duty order on stainless steel bar from Japan...

  4. Microstructure and wear resistance of spray-formed supermartensitic stainless steel

    Directory of Open Access Journals (Sweden)

    Guilherme Zepon

    2013-06-01

    Full Text Available Since the early 90's the oil industry has been encouraging the development of corrosion and wear resistant alloys for onshore and offshore pipeline applications. In this context supermartensitic stainless steel was introduced to replace the more expensive duplex stainless steel for tubing applications. Despite the outstanding corrosion resistance of stainless steels, their wear resistance is of concern. Some authors reported obtaining material processed by spray forming, such as ferritic stainless steel, superduplex stainless steel modified with boron, and iron-based amorphous alloys, which presented high wear resistance while maintaining the corrosion performance1,2. The addition of boron to iron-based alloys promotes the formation of hard boride particles (M2B type which improve their wear resistances3-9. This work aimed to study the microstructure and wear resistance of supermartensitic stainless steel modified with 0.3 wt. (% and 0.7 wt. (% processed by spray forming (SF-SMSS 0.3%B and SF-SMSS 0.7%B, respectively. These boron contents were selected in order to improve the wear resistance of supermartensitic stainless steel through the formation of uniformly distributed borides maintaining the characteristics of the corrosion resistant matrix. SF-SMSS 0.7%B presents an abrasive wear resistance considerably higher than spray-formed supermartensitic stainless steel without boron addition (SF-SMSS.

  5. Influence of surface roughness of stainless steel on microbial adhesion and corrosion resistance

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Bagge-Ravn, Dorthe; Kold, John;

    2003-01-01

    Abstract The aim of this study was to evaluate if hygienic characteristics of stainless steel used in the food industry could be improved by smoothing surface roughness from an Ra of 0.9 to 0.01 ƒÝm. The adherence of Pseudomonas sp., Listeria monocytogenes and Candida lipolytica to stainless steel...

  6. 75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

    Science.gov (United States)

    2010-11-01

    ... stainless steel flanges from India and Taiwan (65 FR 49964). Following second five-year reviews by Commerce... duty orders on imports of forged stainless steel flanges from India and Taiwan (71 FR 3457, January 23... part 201), and part 207, subparts A, D, E, and F (19 CFR part 207), as most recently amended at 74...

  7. On the Development of the Brass-Type Texture in Austenitic Stainless Steel

    OpenAIRE

    Singh, C. D.

    1993-01-01

    It has been clarified and demonstrated that the conclusions drawn by Singh, Ramaswamy and Suryanarayana (1992) in an investigation of development of rolling textures in an austenitic stainless steel are correct. The observations and reinterpretations drawn by Leffers (1993) are without any proper scientific basis and do not hold good at least in austenitic stainless steel.

  8. Stress corrosion cracking of stainless steels in NaCl solutions

    Science.gov (United States)

    Speidel, Markus O.

    1981-05-01

    The metallurgical influences on the stress corrosion resistance of many commercial stainless steels have been studied using the fracture mechanics approach. The straight-chromium ferritic stainless steels, two-phase ferritic-austenitic stainless steels and high-nickel solid solutions (like alloys 800 and 600) investigated are all fully resistant to stress corrosion cracking at stress intensity (K1) levels ≤ MN • m-3/2 in 22 pct NaCl solutions at 105 °C. Martensitic stainless steels, austenitic stainless steels and precipitation hardened superalloys, all with about 18 pct chromium, may be highly susceptible to stress corrosion cracking, depending on heat treatment and other alloying elements. Molybdenum additions improve the stress corrosion cracking resistance of austenitic stainless steels significantly. The fracture mechanics approach to stress corrosion testing of stainless steels yields results which are consistent with both the service experience and the results from testing with smooth specimens. In particular, the well known “Copson curve” is reproduced by plotting the stress corrosion threshold stress intensity (ATISCC) vs the nickel content of stainless steels with about 18 pct chromium.

  9. 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.)

  10. Internal attachment of laser beam welded stainless steel sheathed thermocouples into stainless steel upper end caps in nuclear fuel rods for the LOFT Reactor

    International Nuclear Information System (INIS)

    The Exxon Nuclear Company, Inc., acting as a subcontractor to EG and G Idaho Inc., Idaho National Engineering Laboratory, Idaho Falls, Idaho, conducted a laser beam welding study to attach internal stainless steel thermocouples into stainless steel upper end caps in nuclear fuel rods. The objective of this study was to determine the feasibility of laser welding a single 0.063 inch diameter stainless steel (304) sheathed thermocouple into a stainless steel (316) upper end cap for nuclear fuel rods. A laser beam was selected because of the extremely high energy input in unit volume that can be achieved allowing local fusion of a small area irrespective of the difference in material thickness to be joined. A special weld fixture was designed and fabricated to hold the end cap and the thermocouple with angular and rotational adjustment under the laser beam. A commercial pulsed laser and energy control system was used to make the welds

  11. Beneficially reusing LLRW the Savannah River Site Stainless Steel Program

    International Nuclear Information System (INIS)

    With 68 radioactively contaminated excess Process Water Heat Exchangers the Savannah River Site launched its program to turn potential LLRW metal liabilities into assets. Each Heat Exchanger contains approximately 100 tons of 304 Stainless Steel and could be disposed as LLRW by land burial. Instead the 7000 tons of metal will be recycled into LLRW, HLW, and TRU waste containers thereby eliminating the need for near term land disposal and also eliminating the need to add more clean metal to the waste stream. Aspects of the partnership between DOE and Private Industry necessary to accomplish this new mission are described. A life cycle cost analysis associated with past practices of using carbon steel containers to indefinitely store material (contributing to the creation of today's legacy waste problems) is presented. The avoided cost calculations needed to support the economics of the ''Indifference'' decision process in assessing the Beneficial Reuse option relative to the Burial option are described

  12. Nanoindentation Size Effect on Type 316 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    YAOYuan; QIAOLi-jie; QiangShi-san; CAOXian-kun; CHUWu-yan

    2004-01-01

    Nanoinlentation size effect was investigated under very low loads on type 316 stainless steel.Nanoindentation measurements were carried out on the samples surfaces with a Berkovich pytamidal diamond in-denter applying loads in the range of 25-1000μN. Simultaneously, AFM images of the sample surface were recorded before and after indentation process. For type 316 stairdess steel, the indentation size effect was found.The results were discussed in the terms of the model of geometrically necessary dislocations proposed to interpret the indentation size effect. It can be seen that the square of the nanohardness, H2, vs the ineerse of indentation depth, 1/h, is linearly dependent on the indented depth in the range of 25-150nm, which is a good qualitative agreement with the predictions of the model. However, for shallow indents, the slope of the line severely changes.Some possible mechanisms for this change were proposed.

  13. Small punch creep test in a 316 austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Saucedo-Munoz, M. L.; Komazaki, S. I.; Hashida, T.; Lopez-Hirata, V. M.

    2015-03-30

    The small punch creep test was applied to evaluate the creep behavior of a 316 type austenitic stainless steel at temperatures of 650, 675 and 700 degree centigrade. The small punch test was carried out using a creep tester with a specimen size of 10x10x0.3 mm at 650, 675 and 700 degree centigrade using loads from 199 to 512 N. The small punch creep curves show the three stages found in the creep curves of the conventional uniaxial test. The conventional creep relationships which involve parameters such as creep rate, stress, time to rupture and temperature were followed with the corresponding parameters of small punch creep test and they permitted to explain the creep behavior in this steel. The mechanism and activation energy of the deformation process were the grain boundary sliding and diffusion, respectively, during creep which caused the intergranular fracture in the tested specimens. (Author)

  14. Corrosion of AISI 304 stainless steel in polluted seawater

    International Nuclear Information System (INIS)

    The sequence of microbiofouling settlement on AISI 304 stain steel samples exposed to polluted harbor sea water of a power cooling water intake is studied. The firts sates of bacterial colonization are followed by means of scanning electron microscopy during two weeks of exposure. The relation between microbiofouling and corrosion is also followed by scanning electron microscopy and evaluated through electrochemical polarization experiments. The results obtained show that microbial colonization and extracellular polimeric substances forming the biofilms have a marked influence on the electrochemical behaviour of stainless steel in sea water. Laboratory experiments using inorganic chloride solutions or artificial sea water show a considerably lesser attack of the metal than those performed 'in situ' with natural sea water. Passivity breadown is highly facilitated when complex biological and inorganic deposits (fouling) have settled on the metal surface. (Author)

  15. Influence of nitrogen in the shielding gas on corrosion resistance of duplex stainless steel welds

    Science.gov (United States)

    Bhatt, R. B.; Kamat, H. S.; Ghosal, S. K.; de, P. K.

    1999-10-01

    The influence of nitrogen in shielding gas on the corrosion resistance of welds of a duplex stainless steel (grade U-50), obtained by gas tungsten arc (GTA) with filler wire, autogenous GTA (bead-on-plate), electron beam welding (EBW), and microplasma techniques, has been evaluated in chloride solutions at 30 °C. Pitting attack has been observed in GTA, electron beam welding, and microplasma welds when welding has been carried out using pure argon as the shielding gas. Gas tungsten arc welding with 5 to 10% nitrogen and 90 to 95% argon, as the shielding gas, has been found to result in an improved pitting corrosion resistance of the weldments of this steel. However, the resistance to pitting of autogenous welds (bead-on-plate) obtained in pure argon as the shielding gas has been observed to remain unaffected. Microscopic examination, electron probe microanalysis (EPMA), and x-ray diffraction studies have revealed that the presence of nitrogen in the shielding gas in the GTA welds not only modifies the microstructure and the austenite to ferrite ratio but also results in a nearly uniform distribution of the various alloying elements, for example, chromium, nickel, and molybdenum among the constitutent phases, which are responsible for improved resistance to pitting corrosion.

  16. Effect of beam oscillation on borated stainless steel electron beam welds

    International Nuclear Information System (INIS)

    Borated stainless steels are used in nuclear power plants to control neutron criticality in reactors as control rods, shielding material, spent fuel storage racks and transportation casks. In this study, bead on plate welds were made using gas tungsten arc welding (GTAW) and electron beam welding (EBW) processes. Electron beam welds made using beam oscillation technique exhibited higher tensile strength values compared to that of GTA welds. Electron beam welds were found to show fine dendritic microstructure while GTA welds exhibited larger dendrites. While both processes produced defect free welds, GTA welds are marked by partially melted zone (PMZ) where the hardness is low. EBW obviate the PMZ failure due to low heat input and in case of high heat input GTA welding process failure occurs in the PMZ.

  17. Stress corrosion cracking of duplex stainless steels in caustic solutions

    Science.gov (United States)

    Bhattacharya, Ananya

    Duplex stainless steels (DSS) with roughly equal amount of austenite and ferrite phases are being used in industries such as petrochemical, nuclear, pulp and paper mills, de-salination plants, marine environments, and others. However, many DSS grades have been reported to undergo corrosion and stress corrosion cracking in some aggressive environments such as chlorides and sulfide-containing caustic solutions. Although stress corrosion cracking of duplex stainless steels in chloride solution has been investigated and well documented in the literature but the SCC mechanisms for DSS in caustic solutions were not known. Microstructural changes during fabrication processes affect the overall SCC susceptibility of these steels in caustic solutions. Other environmental factors, like pH of the solution, temperature, and resulting electrochemical potential also influence the SCC susceptibility of duplex stainless steels. In this study, the role of material and environmental parameters on corrosion and stress corrosion cracking of duplex stainless steels in caustic solutions were investigated. Changes in the DSS microstructure by different annealing and aging treatments were characterized in terms of changes in the ratio of austenite and ferrite phases, phase morphology and intermetallic precipitation using optical micrography, SEM, EDS, XRD, nano-indentation and microhardness methods. These samples were then tested for general and localized corrosion susceptibility and SCC to understand the underlying mechanisms of crack initiation and propagation in DSS in the above-mentioned environments. Results showed that the austenite phase in the DSS is more susceptible to crack initiation and propagation in caustic solutions, which is different from that in the low pH chloride environment where the ferrite phase is the more susceptible phase. This study also showed that microstructural changes in duplex stainless steels due to different heat treatments could affect their SCC

  18. The retention of iodine in stainless steel sample lines

    Energy Technology Data Exchange (ETDEWEB)

    Evans, G.J.; Deir, C. [Univ. of Toronto (Canada); Ball, J.M. [Whiteshell Laboratories, Pinawa (Canada)

    1995-02-01

    Following an accident in a multi-unit CANDU nuclear generating station, decontamination of air vented from containment would play a critical role in minimizing the release of iodine to the environment. The concentration of gas phase iodine in containment air would be measured using the post accident radiation monitoring system, requiring that air samples be passed through a considerable length of tubing to a remote location where the desired measurements could safely be made. A significant loss of iodine, due to adsorption on the sample line surfaces, could greatly distort the measurement. In this study, the retention of I{sub 2}(g) on stainless steel was evaluated in bench scale experiments in order to evaluate, and if possible minimise, the extent of any such line losses. Experiments at the University of Toronto were performed using 6 inch lengths of 1/4 inch stainless steel tubing. Air, containing I-131 labelled I{sub 2}(g), ranging in concentration from 10{sup {minus}10} to 10{sup {minus}6} mol/dm{sup 3} and relative humidity (:RH) from 20 to 90 %, was passed through tubing samples maintained at temperatures ranging from 25 to 90{degrees}C. Adsorption at low gas phase iodine concentrations differed substantially from that at higher concentrations. The rate of deposition was proportional to the gas phase concentration, giving support to the concept of a first order deposition velocity. The surface loading increased with increasing relative humidity, particularly at low RH values, while the deposition rate decreased with increasing temperature. Surface water on the steel may play an important role in the deposition process. The chemisorbed iodine was located primarily in areas of corrosion. Furthermore, water used to wash the steel contained Fe, Mn and iodine in the form of iodide, suggesting that I{sub 2} reacted to form metal iodides. The deposition of I{sub 2} was also found to depend on the initial surface condition.

  19. Phase transformations evaluation on a UNS S31803 duplex stainless steel based on nondestructive testing

    Energy Technology Data Exchange (ETDEWEB)

    Macedo Silva, Edgard de, E-mail: edgard@cefetpb.edu.br [Centro federal de Educacao Tecnologica da Paraiba (CEFET PB), Area da Industria, Avenida 1o de Maio, 720 - 58015-430 - Joao Pessoa/PB (Brazil); Costa de Albuquerque, Victor Hugo, E-mail: victor.albuquerque@fe.up.pt [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Pereira Leite, Josinaldo, E-mail: josinaldo@ct.ufpb.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Gomes Varela, Antonio Carlos, E-mail: varela@cefetpb.edu.br [Universidade Federal da Paraiba (UFPB), Departamento de Engenharia Mecanica (DEM), Cidade Universitaria, S/N - 58059-900 - Joao Pessoa/PB (Brazil); Pinho de Moura, Elineudo, E-mail: elineudo@pq.cnpq.br [Universidade Federal do Ceara (UFC), Departamento de Engenharia Metalurgica e de Materiais, Campus do Pici, Bloco 715, 60455-760 - Fortaleza/CE (Brazil); Tavares, Joao Manuel R.S., E-mail: tavares@fe.up.pt [Faculdade de Engenharia da Universidade do Porto (FEUP), Departamento de Engenharia Mecanica e Gestao Industrial (DEMEGI)/Instituto de Engenharia Mecanica e Gestao Industrial - INEGI, Rua Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal)

    2009-08-15

    Duplex stainless steel presents special mechanical properties such as, for example, mechanical and corrosion strength, becoming competitive in relation to the other types of stainless steel. One of the great problems of duplex stainless steel microstructural changes study is related to embrittlement above 300 deg. C, with the precipitation of the {alpha}' phase occurring over the ferritic microstructure. Aiming to characterise embrittlement of duplex stainless steel, hardening kinetics, from 425 to 475 deg. C, was analysed through the speed of sound, Charpy impact energy, X-ray diffraction, hardness and microscopy parameters. The presence of two hardening stages, detected through the speed of sound, was observed, one being of brittle characteristic and the other ductile. Moreover, the speed of sound showed a direct correlation with the material's hardness. Thus, it is concluded that the speed of sound is a promising nondestructive parameter to follow-up embrittlement in duplex stainless steel.

  20. Antibacterial Mechanism of Copper-bearing Antibacterial Stainless Steel against E.Coli

    Institute of Scientific and Technical Information of China (English)

    Li NAN; Weichao YANG; Yongqian LIU; Hui XU; Ying LI; Manqi L(U); Ke YANG

    2008-01-01

    A preliminary study was made on the antibacterial mechanism of copper-bearing antibacterial stainless steels against E.coli through experiments of microbiology such as EDTA (ethylenediaminetetraacetic acid) complex- ing, DNA smearing and AFM (atomic force microscope) observation. It was measured that the antibacterial stainless steels showed excellent antibacterial functions with antibacterial rate to E.coli over 99.99%. The antibacterial rate was weak if the bacteria solution was complexed by EDTA, indicating that the copper ions play a dominant role in the antibacterial effect of the antibacterial stainless steels. The electrophoresis experi- ment did not show the phenomenon of DNA smearing for E.coli after contacting antibacterial stainless steels, which meant that DNA of E.coli was not obviously damaged. It was observed by AFM that the morphology of E.coli changed a lot after contacting antibacterial stainless steels, such as cell walls being seriously changed and lots of contents in the cells being leaked.

  1. 76 FR 38686 - Stainless Steel Wire Rod From India; Institution of a Five-Year Review Concerning the Antidumping...

    Science.gov (United States)

    2011-07-01

    ... on imports of stainless steel wire rod from India (58 FR 63335). Following first five-year reviews by... duty order on imports of stainless steel wire rod from India (65 FR 47403). Following second five-year... antidumping duty order on imports of stainless steel wire rod from India (71 FR 45023). The Commission is...

  2. Influence of silver additions to type 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tseng, I-Sheng; Møller, Per;

    2010-01-01

    techniques. The microstructure of these 316 stainless steels was examined, and the influences of silver additions to 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance were investigated. This study suggested that silver-bearing 316 stainless steels could be used in...

  3. Experimental Investigation on the Performance of Armour Grade Q&T Steel Joints Fabricated by Flux Cored Arc Welding with Low Hydrogen Ferritic Consumables

    Institute of Scientific and Technical Information of China (English)

    G. Magudeeswaran; V. Balasubramanian; G. Madhusudhan Reddy; G. Gopalakrishnan

    2009-01-01

    Quenched and Tempered (Q&T) steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. These steels are prone to hydrogen induced cracking (HIC) and softening in the heat affected zone (HAZ) after welding. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only available remedy to avoid HIC because of higher solubility for hydrogen in austenitic phase. Recent studies revealed that low hydrogen ferritic (LHF) steel consumables can also be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits and required resistance against cold cracking. Hence, in this investigation an attempt has been made to study the performance of armour grade Q&T steel joints fabricated by flux cored arc welding with LHF steel consumables. Two different consumables namely (i) austenitic stainless steel and (ii) low hydrogen ferritic steel have been used to fabricate the joints by flux cored arc welding (FCAW) process. The joints fabricated by LHF consumable exhibited superior transverse tensile properties due to the presence of ferrite microstructure in weld metal. The joints fabricated by ASS consumable showed higher impact toughness due to the presence of austenitic phase in weld metal microstructure. The HAZ softening in coarse grain heat affected zone (CGHAZ) is less in the joints fabricated using LHF consumable due to the lower heat input involved during fabrication compared to the joints fabricated using ASS consumables.

  4. Reliability of welded austenitic stainless steel containing base metal delta ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Shalaby, Hamdy M. [Kuwait Institute for Scientific Research (Kuwait)

    2004-07-01

    The paper presents the results of a failure case study carried out on welded 304L stainless steel (SS) pipeline of waste gas header (WGH). The environment inside the WGH was mainly wet steam with hydrocarbons, H{sub 2}S, oxygen, CO{sub 2}, organic acids, and organic chlorides. The outside pipe wall temperature was 91-97 deg C. The failure of the pipe was at the heat-affected zone (HAZ). The study was made on four welded pipeline samples, three of which were in service. The pipe samples were welded using three different techniques that included autogenous gas tungsten arc, shielded metal arc, and flux core arc. The investigation revealed that cracking at HAZ was due to base metal delta ferrite decay accompanied with sigma phase formation due to high heat input during welding. However, the morphology and orientation of the cracks suggested that stress-rupture and stress corrosion cracking had occurred. The presence of base metal delta ferrite made all used welding procedures un-successful. The study concluded that utilization of delta ferrite free austenitic SS should eliminate the problem. (author)

  5. 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.

  6. Compresibility and sinterability of HCx PM steel diluted with stainless steels

    Directory of Open Access Journals (Sweden)

    Elena Gordo

    2003-12-01

    Full Text Available HCx powder metallurgy steel contains in its composition high contents of Cr and C, and significant quantities of alloy elements typical of tool steels (Mo, V, W, to provide the corrosion resistance of stainless steel with wear resistance of tool steels. HCx appears to be a suitable material for applications in aggressive environments, as valve seat inserts in automotive engines. However, this steel presents a low compressibility leading to high production costs. In this work, some results carried out to improve the compressibility of HCx are presented. The way to attempt this improvement is the dilution of base material with two stainless steels, the ferritic 430LHC and the austenitic 316L. The powder mixes prepared were uniaxially pressed to study the compressibility. The sinterability was study by determining of density, hardness, transverse rupture strength (TRS and microstructural evolution after vacuum sintering at different temperatures. As a result, better compressibility is observed in the mixes although not all of them present the properties required.

  7. Effect of thermal aging on mechanical properties of cast stainless steels

    International Nuclear Information System (INIS)

    A procedure and correlations are presented for predicting mechanical properties of cast stainless steels in service at temperatures <450 degrees C from known material information. The ''saturation'' fracture properties of a cast stainless steel, i.e., the minimum values that would be achieved for the material after long-term service, are estimated from the chemical composition of the steel. Fracture properties as a function of time and temperature of service are estimated from the kinetics of embrittlement, which are also determined from chemical composition. The correlations successfully predict fracture toughness, Charpy-impact, and tensile properties of cast stainless steels from the Shippingport-, Ringhals-, and Gundremmingen-reactor components

  8. Development of stainless steels for nuclear power plant - Advanced nuclear materials development -

    International Nuclear Information System (INIS)

    This report reviews the status of R and D and the material specifications of nuclear components in order to develop the stainless steels for nuclear applications, and the technology of computer-assisted alloy design is developed to establish the thermodynamic data of Fe-Cr-Ni-Mo-Si-C-N system which is the basic stainless steel systems. High strength and corrosion resistant stainless steels, 316LN and super clean 347, are developed, and the manufacturing processes and heat treatment conditions are determined. In addition, a martensitic steel is produced as a model alloy for turbine blade, and characterized. The material properties showed a good performance for nuclear applications. (Author)

  9. Phase characterization in two centrifugally cast HK stainless steel tubes

    International Nuclear Information System (INIS)

    The petrochemical industry has been using 25% Cr - 20% Ni centrifugally cast stainless steel since the early 1960s in reformer and pyrolysis furnaces. This class of material has replaced the traditional superalloys showing similar creep behavior, with substantial reduction in costs. The use of the centrifugal casting technique for tube production has also contributed to better quality in these components. During the past two decades, several studies have been conducted concerning the improvement in the performance of this material at high temperatures. Some of them were related to failure analysis and life prediction, while others were related to the chemical composition balance and to new alloying procedures. As a consequence, a new generation of centrifugally cast steels has been developed in the form of niobium-modified HK and HP steels. The creep resistance of these alloys appears to be dependent on the composition, morphology, and distribution of carbides that form within them. The purpose of the study reported herein is to characterize the precipitation effects occurring during long- term service in two HK-type steels, one being of basic HK composition and the other a niobium-modified alloy

  10. Effect of Post-Weld Heat Treatment on Mechanical and Electrochemical Properties of Gas Metal Arc-Welded 316L (X2CrNiMo 17-13-2) Stainless Steel

    Science.gov (United States)

    Muhammad, F.; Ahmad, A.; Farooq, A.; Haider, W.

    2016-10-01

    In the present research work, corrosion behavior of post-weld heat-treated (PWHT) AISI 316L (X2CrNiMo 17-13-2) specimens joined by gas metal arc welding is compared with as-welded samples by using potentiodynamic polarization technique. Welded samples were PWHT at 1323 K for 480 s and quenched. Mechanical properties, corrosion behavior and microstructures of as-welded and PWHT specimens were investigated. Microstructural studies have shown grain size refinement after PWHT. Ultimate tensile strength and yield strength were found maximum for PWHT samples. Bend test have shown that PWHT imparted ductility in welded sample. Fractographic analysis has evidenced ductile behavior for samples. Potentiodynamic polarization test was carried out in a solution composed of 1 M H2SO4 and 1 N NaCl. Corrosion rate of weld region was 127.6 mpy, but after PWHT, it was decreased to 13.12 mpy.

  11. Effect of Post-Weld Heat Treatment on Mechanical and Electrochemical Properties of Gas Metal Arc-Welded 316L (X2CrNiMo 17-13-2) Stainless Steel

    Science.gov (United States)

    Muhammad, F.; Ahmad, A.; Farooq, A.; Haider, W.

    2016-08-01

    In the present research work, corrosion behavior of post-weld heat-treated (PWHT) AISI 316L (X2CrNiMo 17-13-2) specimens joined by gas metal arc welding is compared with as-welded samples by using potentiodynamic polarization technique. Welded samples were PWHT at 1323 K for 480 s and quenched. Mechanical properties, corrosion behavior and microstructures of as-welded and PWHT specimens were investigated. Microstructural studies have shown grain size refinement after PWHT. Ultimate tensile strength and yield strength were found maximum for PWHT samples. Bend test have shown that PWHT imparted ductility in welded sample. Fractographic analysis has evidenced ductile behavior for samples. Potentiodynamic polarization test was carried out in a solution composed of 1 M H2SO4 and 1 N NaCl. Corrosion rate of weld region was 127.6 mpy, but after PWHT, it was decreased to 13.12 mpy.

  12. Effect of heating rate on sintered series 300 stainless steel

    Directory of Open Access Journals (Sweden)

    Ornmanee Coovattanachai

    2010-05-01

    Full Text Available Stainless steel powders (303L, 304L, 310L and 316L were formed into tensile test bars using the “press and sinter”process. Most processing parameters, except heating rate, were kept constant. During the heating of the experimental specimensfrom 700°C to the sintering temperature of 1300°C, heating rates were varied, e.g., 2.5, 5.0, and 10.0°C/min. Experimentalresults showed that a material heated with a low heating rate tended to have higher sintered density and tensile strength.However, the low heating rate caused grain growth in the sintered material. These results are in contradiction with the improved densification of some ceramics by ultra rapid heating. The reasons for contradiction are as follows. First, the heatingrates employed in this work are not very different. The second is attributed to small thermal gradients generated in thethin metal powder compacts. Because of these reasons, densification of the sintered stainless steels series 300 is controlled by an isothermal condition. The low heating rate allows longer time for atomic diffusion, which is an important sintering factor. This means more atoms move to points of contact between powder particles to form necking and to cause neckinggrowth. This results in better sintering. However, the low heating rate means that the materials are exposed to heat for longertime and thus their grains have a tendency to grow.

  13. Thermal treatment effects on laser surface remelting duplex stainless steel

    Science.gov (United States)

    do Nascimento, Alex M.; Ierardi, Maria Clara F.; Aparecida Pinto, M.; Tavares, Sérgio S. M.

    2008-10-01

    In this paper the microstructural changes and effects on corrosion resistance of duplex stainless steels UNS S32304 and UNS S32205, commonly used by the petroleum industry, were studied, following the execution of laser surface remelting (LSM) and post-thermal treatments (TT). In this way, data was obtained, which could then be compared with the starting condition of the alloys. In order to analyze the corrosion behaviour of the alloys in the as-received conditions, treated with laser and after post-thermal treatments, cyclic polarization tests were carried out. A solution of 3.5% NaCl (artificial sea water) was used, as duplex stainless steels are regularly used by the petroleum industry in offshore locations. The results obtained showed that when laser surface treated, due to rapid resolidification, the alloys became almost ferritic, and since the level of nitrogen in the composition of both alloys is superior to their solubility limit in ferrite, a precipitation of Cr2N (chromium nitrides) occurred in the ferritic matrix, causing loss of corrosion resistance, thus resulting in an increase in surface hardness. However, after the post-thermal treatment the alloys corrosion resistance was restored to values close to those of the as-received condition.

  14. The diffusivity of hydrogen in Nb stabilized stainless steel

    Science.gov (United States)

    Outlaw, R. A.; Peterson, D. T.

    1983-01-01

    The evolution of hydrogen from 347 stainless steel has been studied by using a real time dynamic technique under ultrahigh vacuum conditions. Auger electron spectroscopy was used to determine the surface composition as a function of time and temperature. The surface film on the electropolished samples was found to be approximately 15 A thick and consisted of a carbon-oxygen complex and a metal oxide (FexOy). Upon heating to 400 C, the carbon-oxygen complex desorbed as CO and the remaining oxygen and carbon began to incorporate. Also at this temperature sulfur began to diffuse out of the bulk to the surface and at approximately 800 C formed a complete monolayer. At 900 C, carbon and oxygen virtually disappeared, leaving the monolayer of sulfur as the only surface contaminant. The hydrogen diffusivity was found to follow closely the equation D = 7.01 x 10 to the -7th exp(-48.0/RT) sq m per second over the entire temperature range studied, thus indicating that hydrogen evolution is not significantly affected by the changing surface composition. The somewhat higher value of the diffusivity obtained in this work compared to past measurements in austenitic stainless steels may indicate the importance of sample preprocessing and ultrahigh vacuum conditions in minimizing the effects of surface layers.

  15. Intergranular stress distributions in polycrystalline aggregates of irradiated stainless steel

    Science.gov (United States)

    Hure, J.; El Shawish, S.; Cizelj, L.; Tanguy, B.

    2016-08-01

    In order to predict InterGranular Stress Corrosion Cracking (IGSCC) of post-irradiated austenitic stainless steel in Light Water Reactor (LWR) environment, reliable predictions of intergranular stresses are required. Finite elements simulations have been performed on realistic polycrystalline aggregate with recently proposed physically-based crystal plasticity constitutive equations validated for neutron-irradiated austenitic stainless steel. Intergranular normal stress probability density functions are found with respect to plastic strain and irradiation level, for uniaxial loading conditions. In addition, plastic slip activity jumps at grain boundaries are also presented. Intergranular normal stress distributions describe, from a statistical point of view, the potential increase of intergranular stress with respect to the macroscopic stress due to grain-grain interactions. The distributions are shown to be well described by a master curve once rescaled by the macroscopic stress, in the range of irradiation level and strain considered in this study. The upper tail of this master curve is shown to be insensitive to free surface effect, which is relevant for IGSCC predictions, and also relatively insensitive to small perturbations in crystallographic texture, but sensitive to grain shapes.

  16. Fiber laser welding of AISI 304 stainless steel plates

    International Nuclear Information System (INIS)

    Compared with conventional lasers, fiber laser welding is characterized by high melting efficiency, deferent keyhole modes and power density characteristics, which could affect the heat and melt flow of the molten pool during welding. The objective of the present work was to study the fiber laser weldability of 5 mm thick AISI 304 austenitic stainless steel plates; therefore, bead-on-plate welding was exploited on AISI 304 stainless steel plates with different laser powers, welding speeds, defocused distances with different types of shielding gas and their effects on the weld zone geometry and properties and final solidification microstructure at room temperature. Laser power, welding speed and defocused distance have a great effect on the bead appearance and weld zone shape while almost no significant effect on both the type of microstructure and mechanical properties of welds. The microstructure of all laser welds was always austenitic including about 3-5 % ferrite. However, the lower the laser power and/or the higher the welding speed, the finer solidification structure, primary ferrite or mixed-mode solidification resulted in crack-free welds. (author)

  17. Development of Cast Alumina-Forming Austenitic Stainless Steels

    Science.gov (United States)

    Muralidharan, G.; Yamamoto, Y.; Brady, M. P.; Walker, L. R.; Meyer, H. M., III; Leonard, D. N.

    2016-09-01

    Cast Fe-Ni-Cr chromia-forming austenitic stainless steels with Ni levels up to 45 wt.% are used at high temperatures in a wide range of industrial applications that demand microstructural stability, corrosion resistance, and creep strength. Although alumina scales offer better corrosion protection at these temperatures, designing cast austenitic alloys that form a stable alumina scale and achieve creep strength comparable to existing cast chromia-forming alloys is challenging. This work outlines the development of cast Fe-Ni-Cr-Al austenitic stainless steels containing about 25 wt.% Ni with good creep strength and the ability to form a protective alumina scale for use at temperatures up to 800-850°C in H2O-, S-, and C-containing environments. Creep properties of the best alloy were comparable to that of HK-type cast chromia-forming alloys along with improved oxidation resistance typical of alumina-forming alloys. Challenges in the design of cast alloys and a potential path to increasing the temperature capability are discussed.

  18. Determination of delta ferrite volumetric fraction in austenitic stainless steel

    International Nuclear Information System (INIS)

    Measurements of delta ferrite volumetric fraction in AISI 304 austenitic stainless steels were done by X-ray diffraction, quantitative metallography (point count) and by means of one specific commercial apparatus whose operational principle is magnetic-inductive: The Ferrite Content Meter 1053 / Institut Dr. Foerster. The results obtained were comparated with point count, the reference method. It was also investigated in these measurements the influence of the martensite induced by mechanical deformation. Determinations by X-ray diffraction, by the ratio between integrated intensities of the ferrite (211) and austenite (311) lines, are in excelent agreement with those taken by point count. One correction curve for the lectures of the commercial equipment in focus was obtained, for the range between zero and 20% of delta ferrite in 18/8 stainless steels. It is demonstrated that, depending on the employed measurement method and surface finishing of the material to be analysed, the presence of martensite produced by mechanical deformation of the austenitic matrix is one problem to be considered. (Author)

  19. Aging degradation of cast stainless steel: status and program

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, O.K.; Ayrault, G.

    1983-10-01

    A program has been initiated to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are reviewed to determine the critical parameters that control the aging behavior and to define the objectives and scope of the investigation. The test matrices for microstructural studies and mechanical property measurements are presented. The initial experimental effort is focussed on characterizing the microstructure of long-term, low-temperature aged material. Specimens from three heats of cast CF-8 and CF-8M stainless steel aged for up to 70,000 h at 300, 350, and 400/sup 0/C were obtained from George Fisher Ltd., of Switzerland. Initial analyses reveal the formation of three different types of precipitates which are not ..cap alpha..'. An FCC phase, similar to the M/sub 23/C/sub 6/ precipitates, was present in all the long-term aged material. 15 references, 10 figures, 2 tables.

  20. Dynamic Recrystallization and Hot Workability of 316LN Stainless Steel

    Directory of Open Access Journals (Sweden)

    Chaoyang Sun

    2016-07-01

    Full Text Available To identify the optimal deformation parameters for 316LN austenitic stainless steel, it is necessary to study the macroscopic deformation and the microstructural evolution behavior simultaneously in order to ascertain the relationship between the two. Isothermal uniaxial compression tests of 316LN were conducted over the temperature range of 950–1150 °C and for the strain rate range of 0.001–10 s−1 using a Gleeble-1500 thermal-mechanical simulator. The microstructural evolution during deformation processes was investigated by studying the constitutive law and dynamic recrystallization behaviors. Dynamic recrystallization volume fraction was introduced to reveal the power dissipation during the microstructural evolution. Processing maps were developed based on the effects of various temperatures, strain rates, and strains, which suggests that power dissipation efficiency increases gradually with increasing temperature and decreasing stain rate. Optimum regimes for the hot deformation of 316LN stainless steel were revealed on conventional hot processing maps and verified effectively through the examination of the microstructure. In addition, the regimes for defects of the product were also interpreted on the conventional hot processing maps. The developed power dissipation efficiency maps allow optimized processing routes to be selected, thus enabling industry producers to effectively control forming variables to enhance practical production process efficiency.

  1. Large strain cyclic behavior of metastable austenic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Geijselaers, H.J.M., E-mail: h.j.m.geijselaers@utwente.nl; Hilkhuijsen, P.; Bor, T.C.; Boogaard, A.H. van den

    2015-04-17

    Metastable austenitic stainless steel will transform to martensite when subjected to mechanical working. In this research an austenitic stainless steel has been subjected to large amplitude strain paths containing a strain reversal. During the tests, apart from the stress and the strain also magnetic induction was measured. From the in situ magnetic induction measurements an estimate of the stress partitioning among the phases is determined. When the strain path reversal is applied at low strains, a classical Bauschinger effect is observed. When the strain reversal is applied at higher strains, a higher flow stress is measured after the reversal compared to the flow stress before reversal. Also a stagnation of the transformation is observed, meaning that a higher strain as well as a higher stress than before the strain path change is required to restart the transformation after reversal. The observed behavior can be explained by a model in which for the martensitic transformation a stress induced transformation model is used. The constitutive behavior of both the austenite phase and the martensite is described by a Chaboche model to account for the Bauschinger effect. Mean-field homogenization of the material behavior of the individual phases is employed to obtain a constitutive behavior of the two-phase composite. The overall applied stress, the stress in the martensite phase and the observed transformation behavior during cyclic shear are very well reproduced by the model simulations.

  2. EBSD study of a hot deformed austenitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Mirzadeh, H., E-mail: h-m@gmx.com [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Cabrera, J.M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Fundacio CTM Centre Tecnologic, Av. Bases de Manresa 1, 08242 Manresa (Spain); Najafizadeh, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Calvillo, P.R. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028 Barcelona (Spain); Fundacio CTM Centre Tecnologic, Av. Bases de Manresa 1, 08242 Manresa (Spain)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Microstructural characterization of an austenitic stainless steel by EBSD. Black-Right-Pointing-Pointer The role of twins in the nucleation and growth of dynamic recrystallization. Black-Right-Pointing-Pointer Grain refinement through the discontinuous dynamic recrystallization. Black-Right-Pointing-Pointer Determination of recrystallized fraction using the grain average misorientation. Black-Right-Pointing-Pointer Relationship between recrystallization and the frequency of high angle boundaries. - Abstract: The microstructural evolution of a 304 H austenitic stainless steel subjected to hot compression was studied by the electron backscattered diffraction (EBSD) technique. Detailed data about the boundaries, coincidence site lattice (CSL) relationships and grain size were acquired from the orientation imaging microscopy (OIM) maps. It was found that twins play an important role in the nucleation and growth of dynamic recrystallization (DRX) during hot deformation. Moreover, the conventional discontinuous DRX (DDRX) was found to be in charge of grain refinement reached under the testing conditions studied. Furthermore, the recrystallized fraction (X) was determined from the grain average misorientation (GAM) distribution based on the threshold value of 1.55 Degree-Sign . The frequency of high angle boundaries showed a direct relationship with X. A time exponent of 1.11 was determined from Avrami analysis, which was related to the observed single-peak behavior in the stress-strain flow curves.

  3. Microbially influenced corrosion of stainless steel by manganese oxidizing microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Linhardt, P. [Technische Universitaet Wien, Technische Versuchs- und Forschungsanstalt (TVFA), Karlsplatz 13, 1040 Wien (Austria)

    2004-03-01

    Based on the corrosion behaviour of stainless steels in fresh water and on the electrochemical properties of higher manganese oxides, the mechanism ''Microbially influenced corrosion by manganese oxidizing microorganisms'' (MIC by MOMOs) is presented as the consequence of biomineralized manganese oxides in contact with the metal. Localized corrosion may develop at elevated but normally undercritical chloride concentration in the water. The mechanism was found useful in the analysis of certain cases of unexpected failure of stainless steel in fresh water. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Ausgehend vom Korrosionsverhalten nichtrostender Staehle in Suesswasser und den elektrochemischen Eigenschaften hoeherer Manganoxide wird der Mechanismus ''Mikrobiell beeinflusste Korrosion durch manganoxidierende Mikroorganismen'' als die Folge des Kontaktes von biomineralisiertem Braunstein mit dem metallischen Werkstoff beschrieben. Unter diesen Bedingungen kann Lokalkorrosion bei Chloridkonzentrationen im Wasser entstehen, die normalerweise als unkritisch angesehen werden. Der Mechanismus hat sich bei der Schadensanalyse bestimmter, unerwarteter Korrosionsfaelle bewaehrt. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  4. Tearing resistance of aged cast austenitic stainless steels

    International Nuclear Information System (INIS)

    CF8 and CF8M type cast stainless steels containing about 10 to 25 % ferrite are used in the primary piping of light water reactors (PWRs and BWRs). It is now recognized that these materials are embrittled by thermal aging at the operating temperature (between 2900C and 3300C), mainly due to precipitation hardening of the ferrite by α', and other phases. Extensive research programs are under way in several countries to better understand the mechanisms of embrittlement and to determine the mechanical properties of components as a function of aging time and temperature. In earlier studies thermal aging embrittlement was mainly characterized by the evolutions of the tensile and Charpy impact properties. However the evaluation of reactor coolant circuit integrity through mechanical analyses requires the knowledge of fracture toughness properties. The first measurements of the tearing resistance of a CF8M type severely aged material were presented in 1983 by SLAMA, PETREQUIN and MAGER. Other contributions to the knowledge of the fracture toughness of aged materials were published, but were relative to medium or high toughness materials. The objective of this paper is to present the results of tearing resistance measurements made on a large spectrum of severely embrittled materials, which allow to give lower bound properties for aged CF8 and CF8M type cast stainless steels

  5. Structure change of 430 stainless steel in the heating process

    Institute of Scientific and Technical Information of China (English)

    Xinzhong Liu; Jingtao Han; Wanhua Yu; Shifeng Dai

    2008-01-01

    The microstructure analysis was employed for the ferritic stainless steel (SUS430) with the carbon content from 0.029wt% to 0.100wt% under the simulated heating process condition. The higher carbon sample (430H) contains the duplex phase micro-structure at the temperature of 1150℃; on the other hand, the lower carbon content sample (430L) does not touch two phase area even at the temperature of 1450℃ and has the single phase ferritic microstrucmre. The carbon content need be well controlled for the 430 ferritic stainless steel since it can significandy affect the heating process curve, and the heating process may not be done in the two phase area due to the uncontrolled carbon content. With the low carbon content and the proper soaking time, the grain size is not sensitive to the heating process temperature and the soaking time. In the present heat treatment experiments, the soaking time is about 10 rain, and the processing parameters can be chosen according to the requ'trernent of the gross energy, the efficiency and the continual forming.

  6. Development of cryogenic thermal control heat pipes. [of stainless steels

    Science.gov (United States)

    1978-01-01

    The development of thermal control heat pipes that are applicable to the low temperature to cryogenic range was investigated. A previous effort demonstrated that stainless steel axially grooved tubing which met performance requirements could be fabricated. Three heat pipe designs utilizing stainless steel axially grooved tubing were fabricated and tested. One is a liquid trap diode heat pipe which conforms to the configuration and performance requirements of the Heat Pipe Experiment Package (HEPP). The HEPP is scheduled for flight aboard the Long Duration Flight Exposure Facility (LDEF). Another is a thermal switch heat pipe which is designed to permit energy transfer at the cooler of the two identical legs. The third thermal component is a hybrid variable conductance heat pipe (VCHP). The design incorporates both a conventional VCHP system and a liquid trap diode. The design, fabrication and thermal testing of these heat pipes is described. The demonstrated heat pipe behavior including start-up, forward mode transport, recovery after evaporator dry-out, diode performance and variable conductance control are discussed.

  7. Processing fine stainless-steel slag using spiral concentration.

    Science.gov (United States)

    Wolfe, Eric R; Klima, Mark S

    2008-04-01

    In this study, the effectiveness of spiral concentration to process a fine (-1 mm) stainless-steel slag was evaluated. Specifically, testing was conducted to determine the feasibility of producing a high metal content stainless steel product and a low metal content aggregate product. This involved investigating a key operating variable for both five-and seven-turn spiral concentrators. The raw slag and spiral products were characterized to determine their respective size and metal distributions. Separation testing was carried out using the two full-scale spiral concentrators to evaluate the effects of feed solids concentration on spiral performance at solids feed rates ranging from 15 to 30 kg/min. The results indicated that under certain conditions, a high-quality metal fraction could be produced. For example, using the five-turn spiral, a product containing 95% metal was obtained at a low metal recovery. Both spirals were ineffective at concentrating the aggregate fraction. Overall, the feed solids concentration did not significantly affect the quality or recoveries of the products, particularly for feed solids concentrations less than 35% by weight. In order to improve the metal recoveries and to produce a low-metal aggregate material, reprocessing of the product streams and/or additional liberation of the raw slag would be required. PMID:18324536

  8. Comparison of stainless and mild steel welding fumes in generation of reactive oxygen species

    Directory of Open Access Journals (Sweden)

    Frazer David

    2010-11-01

    Full Text Available Abstract Background Welding fumes consist of a wide range of complex metal oxide particles which can be deposited in all regions of the respiratory tract. The welding aerosol is not homogeneous and is generated mostly from the electrode/wire. Over 390,000 welders were reported in the U.S. in 2008 while over 1 million full-time welders were working worldwide. Many health effects are presently under investigation from exposure to welding fumes. Welding fume pulmonary effects have been associated with bronchitis, metal fume fever, cancer and functional changes in the lung. Our investigation focused on the generation of free radicals and reactive oxygen species from stainless and mild steel welding fumes generated by a gas metal arc robotic welder. An inhalation exposure chamber located at NIOSH was used to collect the welding fume particles. Results Our results show that hydroxyl radicals (.OH were generated from reactions with H2O2 and after exposure to cells. Catalase reduced the generation of .OH from exposed cells indicating the involvement of H2O2. The welding fume suspension also showed the ability to cause lipid peroxidation, effect O2 consumption, induce H2O2 generation in cells, and cause DNA damage. Conclusion Increase in oxidative damage observed in the cellular exposures correlated well with .OH generation in size and type of welding fumes, indicating the influence of metal type and transition state on radical production as well as associated damage. Our results demonstrate that both types of welding fumes are able to generate ROS and ROS-related damage over a range of particle sizes; however, the stainless steel fumes consistently showed a significantly higher reactivity and radical generation capacity. The chemical composition of the steel had a significant impact on the ROS generation capacity with the stainless steel containing Cr and Ni causing more damage than the mild steel. Our results suggest that welding fumes may cause acute

  9. Melting characteristics of the stainless steel generated from the uranium conversion plant

    International Nuclear Information System (INIS)

    The partition ratio of cerium (Ce) and uranium (U) in the ingot, slag and dust phases has been investigated for the effect of the slag type, slag concentration and basicity in an electric arc melting process. An electric arc furnace (EAF) was used to melt the stainless steel wastes, simulated by uranium oxide and the real wastes from the uranium conversion plant in Korea Atomic Energy Research Institute (KAERI). The composition of the slag former used to capture the contaminants such as uranium, cerium, and cesium during the melt decontamination process generally consisted of silica (SiO2), calcium oxide (CaO) and aluminum oxide (Al2O3). Also, Calcium fluoride (CaF2 ), nickel oxide (NiO), and ferric oxide (Fe2O3) were added to provide an increase in the slag fluidity and oxidative potential. Cerium was used as a surrogate for the uranium because the thermochemical and physical properties of cerium are very similar to those of uranium. Cerium was removed from the ingot phase to slag phase by up to 99% in this study. The absorption ratio of cerium was increased with an increase of the amount of the slag former. And the maximum removal of cerium occurred when the basicity index of the slag former was 0.82. The natural uranium (UO2) was partitioned from the ingot phase to the slag phase by up to 95%. The absorption of the natural uranium was considerably dependent on the basicity index of the slag former and the composition of the slag former. The optimum condition for the removal of the uranium was about 1.5 for the basicity index and 15 wt% of the slag former. According to the increase of the amount of slag former, the absorption of uranium oxide in the slag phase was linearly increased due to an increase of its capacity to capture uranium oxide within the slag phase. Through experiments with various slag formers, we verified that the slag formers containing calcium fluoride (CaF2) and a high amount of silica were more effective for a melt decontamination of

  10. Electron Backscatter Diffraction Analysis of Joints Between AISI 316L Austenitic/UNS S32750 Dual-Phase Stainless Steel

    Science.gov (United States)

    Shamanian, Morteza; Mohammadnezhad, Mahyar; Amini, Mahdi; Zabolian, Azam; Szpunar, Jerzy A.

    2015-08-01

    Stainless steels are among the most economical and highly practicable materials widely used in industrial areas due to their mechanical and corrosion resistances. In this study, a dissimilar weld joint consisting of an AISI 316L austenitic stainless steel (ASS) and a UNS S32750 dual-phase stainless steel was obtained under optimized welding conditions by gas tungsten arc welding technique using AWS A5.4:ER2594 filler metal. The effect of welding on the evolution of the microstructure, crystallographic texture, and micro-hardness distribution was also studied. The weld metal (WM) was found to be dual-phased; the microstructure is obtained by a fully ferritic solidification mode followed by austenite precipitation at both ferrite boundaries and ferrite grains through solid-state transformation. It is found that welding process can affect the ferrite content and grain growth phenomenon. The strong textures were found in the base metals for both steels. The AISI 316L ASS texture is composed of strong cube component. In the UNS S32750 dual-phase stainless steel, an important difference between the two phases can be seen in the texture evolution. Austenite phase is composed of a major cube component, whereas the ferrite texture mainly contains a major rotated cube component. The texture of the ferrite is stronger than that of austenite. In the WM, Kurdjumov-Sachs crystallographic orientation relationship is found in the solidification microstructure. The analysis of the Kernel average misorientation distribution shows that the residual strain is more concentrated in the austenite phase than in the other phase. The welding resulted in a significant hardness increase in the WM compared to initial ASS.

  11. Characterization of particle exposure in ferrochromium and stainless steel production.

    Science.gov (United States)

    Järvelä, Merja; Huvinen, Markku; Viitanen, Anna-Kaisa; Kanerva, Tomi; Vanhala, Esa; Uitti, Jukka; Koivisto, Antti J; Junttila, Sakari; Luukkonen, Ritva; Tuomi, Timo

    2016-07-01

    This study describes workers' exposure to fine and ultrafine particles in the production chain of ferrochromium and stainless steel during sintering, ferrochromium smelting, stainless steel melting, and hot and cold rolling operations. Workers' personal exposure to inhalable dust was assessed using IOM sampler with a cellulose acetate filter (AAWP, diameter 25 mm; Millipore, Bedford, MA). Filter sampling methods were used to measure particle mass concentrations in fixed locations. Particle number concentrations and size distributions were examined using an SMPS+C sequential mobile particle sizer and counter (series 5.400, Grimm Aerosol Technik, Ainring, Germany), and a hand-held condensation particle counter (CPC, model 3007, TSI Incorporated, MN). The structure and elemental composition of particles were analyzed using TEM-EDXA (TEM: JEM-1220, JEOL, Tokyo, Japan; EDXA: Noran System Six, Thermo Fisher Scientific Inc., Madison,WI). Workers' personal exposure to inhalable dust averaged 1.87, 1.40, 2.34, 0.30, and 0.17 mg m(-3) in sintering plant, ferrochromium smelter, stainless steel melting shop, hot rolling mill, and the cold rolling mill, respectively. Particle number concentrations measured using SMPS+C varied from 58 × 10(3) to 662 × 10(3) cm(-3) in the production areas, whereas concentrations measured using SMPS+C and CPC3007 in control rooms ranged from 24 × 10(3) to 243 × 10(3) cm(-3) and 5.1 × 10(3) to 97 × 10(3) cm(-3), respectively. The elemental composition and the structure of particles in different production phases varied. In the cold-rolling mill non-process particles were abundant. In other sites, chromium and iron originating from ore and recycled steel scrap were the most common elements in the particles studied. Particle mass concentrations were at the same level as that reported earlier. However, particle number measurements showed a high amount of ultrafine particles, especially in sintering, alloy smelting and melting, and tapping

  12. Characterization of particle exposure in ferrochromium and stainless steel production.

    Science.gov (United States)

    Järvelä, Merja; Huvinen, Markku; Viitanen, Anna-Kaisa; Kanerva, Tomi; Vanhala, Esa; Uitti, Jukka; Koivisto, Antti J; Junttila, Sakari; Luukkonen, Ritva; Tuomi, Timo

    2016-07-01

    This study describes workers' exposure to fine and ultrafine particles in the production chain of ferrochromium and stainless steel during sintering, ferrochromium smelting, stainless steel melting, and hot and cold rolling operations. Workers' personal exposure to inhalable dust was assessed using IOM sampler with a cellulose acetate filter (AAWP, diameter 25 mm; Millipore, Bedford, MA). Filter sampling methods were used to measure particle mass concentrations in fixed locations. Particle number concentrations and size distributions were examined using an SMPS+C sequential mobile particle sizer and counter (series 5.400, Grimm Aerosol Technik, Ainring, Germany), and a hand-held condensation particle counter (CPC, model 3007, TSI Incorporated, MN). The structure and elemental composition of particles were analyzed using TEM-EDXA (TEM: JEM-1220, JEOL, Tokyo, Japan; EDXA: Noran System Six, Thermo Fisher Scientific Inc., Madison,WI). Workers' personal exposure to inhalable dust averaged 1.87, 1.40, 2.34, 0.30, and 0.17 mg m(-3) in sintering plant, ferrochromium smelter, stainless steel melting shop, hot rolling mill, and the cold rolling mill, respectively. Particle number concentrations measured using SMPS+C varied from 58 × 10(3) to 662 × 10(3) cm(-3) in the production areas, whereas concentrations measured using SMPS+C and CPC3007 in control rooms ranged from 24 × 10(3) to 243 × 10(3) cm(-3) and 5.1 × 10(3) to 97 × 10(3) cm(-3), respectively. The elemental composition and the structure of particles in different production phases varied. In the cold-rolling mill non-process particles were abundant. In other sites, chromium and iron originating from ore and recycled steel scrap were the most common elements in the particles studied. Particle mass concentrations were at the same level as that reported earlier. However, particle number measurements showed a high amount of ultrafine particles, especially in sintering, alloy smelting and melting, and tapping

  13. Gas Tungsten Arc Welding of Copper and Mild Steel

    OpenAIRE

    Daniel T; Timotius P; Maziar R

    2016-01-01

    In this paper, copper and mild steel were welded using a gas tungsten arc welding (GTAW) process. To determine the weldablity factor, tests are needed to provide information on mechanical strength, potential defects in structure, and nature of failure. Mechanical testing included transverse tensile tests, micro hardness tests, and bend tests. The results for the transverse tensile test revealed failure occurred at the copper heat affected zone (HAZ) with an ultimate tensile strength of 220MPa...

  14. Significance of stainless steel wire reinforcement on the mechanical properties of GFRP composites

    OpenAIRE

    K. Pazhanivel; G. B. Bhaskar; Elayaperumal, A.

    2014-01-01

    Investigations on flexural and tensile properties of GFRP laminates influenced by stainless steel wire reinforcement were carried out as a novel approach. Plain GFRP laminates and GFRP laminates reinforced with stainless steel wires at different depth with various pitch distances were fabricated by hand layup method. The composite specimens reinforced with steel wires were exposed to low frequency high amplitude cyclic load by using a cam arrangement. Three point bend test was carried out on ...

  15. Industrial Experience with Case Hardening of Stainless Steels by Solution Nitriding

    Institute of Scientific and Technical Information of China (English)

    Hans Berns; Bernd Edenhofer; Roland Zaugg

    2004-01-01

    SolNit(R) is a novel heat treatment to case harden stainless steels with nitrogen instead of carbon. The calculated equilibrium pressure of N2 corresponds well with the nitrogen content in the steel surface. The process is carried out in vacuum furnaces with pressurized gas quenching. Numerous parts of different stainless steels have been successfully SolNit(R) treated in industry leading to superior properties in respect to hardness/strength and corrosion resistance

  16. Interaction of bending and axial load for ferritic stainless steel RHS columns

    OpenAIRE

    Arrayago Luquin, Itsaso; Picci, F; Mirambell Arrizabalaga, Enrique; Real Saladrigas, Esther

    2015-01-01

    Stainless steels are ideal for sustainable structural performances due to their excellent corrosion resistance, appropriate mechanical properties, aesthetic appearance and easy maintenance. However, the nonlinear behaviour and strain-hardening effects characterizing these materials make them different from carbon steel and some specific guidance is necessary. Although some investigations regarding the behaviour of stainless steel beam-columns subjected to combined compression and bending mome...

  17. Influence of grinding operations on surface integrity and chloride induced stress corrosion cracking of stainless steels

    OpenAIRE

    Zhou, Nian

    2016-01-01

    Stainless steels were developed in the early 20th century and are used where both the mechanical properties of steels and corrosion resistance are required. There is continuous research to allow stainless steel components to be produced in a more economical way and be used in more harsh environments. A necessary component in this effort is to correlate the service performance with the production processes. The central theme of this thesis is the mechanical grinding process.  This is commonly ...

  18. Ultra-Pure Ferritic Stainless Steels-Grade, Refining Operation, and Application

    Institute of Scientific and Technical Information of China (English)

    YOU Xiang-mi; JIANG Zhou-hua; LI Hua-bing

    2007-01-01

    The grades of ultra-pure ferritic stainless steels, especially the grades used in automobile exhaust system, were reviewed. The dependence of properties on alloying elements, the refining facilities, and the mechanism of the reactions in steel melts were described in detail. Vacuum, strong stirring, and powder injection proved to be effective technologies in the melting of ultra-pure ferritic stainless steels. The application of the ferritic grades was also briefly introduced.

  19. 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.

  20. Dissimilar Friction Stir Welding Between UNS S31603 Austenitic Stainless Steel and UNS S32750 Superduplex Stainless Steel

    Science.gov (United States)

    Theodoro, Maria Claudia; Pereira, Victor Ferrinho; Mei, Paulo Roberto; Ramirez, Antonio Jose

    2015-02-01

    In order to verify the viability of dissimilar UNS S31603 austenitic and UNS S32750 superduplex stainless steels joined by friction stir welding, 6-mm-thick plates were welded using a PCBN-WRe tool. The welded joints were performed in position control mode at rotational speeds of 100 to 300 rpm and a feed rate of 100 mm/min. The joints performed with 150 and 200 rpm showed good appearance and no defects. The metallographic analysis of both joints showed no internal defects and that the material flow pattern is visible only in the stirred zone (SZ) of the superduplex steel. On the SZ top, these patterns are made of regions of different phases (ferrite and austenite), and on the bottom and central part of the SZ, these patterns are formed by alternated regions of different grain sizes. The ferrite grains in the superduplex steel are larger than those in the austenitic ones along the SZ and thermo-mechanically affected zone, explained by the difference between austenite and ferrite recrystallization kinetics. The amount of ferrite islands present on the austenitic steel base metal decreased near the SZ interface, caused by the dissolving of the ferrite in austenitic matrix. No other phases were found in both joints. The best weld parameters were found to be 200 rpm rotation speed, 100 mm/min feed rate, and tool position control.