WorldWideScience

Sample records for alloy steel transition

  1. Steel alloys

    International Nuclear Information System (INIS)

    Bloom, E.E.; Stiegler, J.O.; Rowcliffe, A.F.; Leitnaker, J.M.

    1977-01-01

    The invention deals with a fuel element for fast breeder reactors. It consits essentially of a uranium oxide, nitride, or carbide or a mixture of these fuels with a plutonium or thorium oxide, nitride, or carbide. The fuel elements are coated with an austenitic stainless steel alloy. Inside the fuel elements, vacancies or small cavities are produced by neutron effects which causes the steel coating to swell. According to the invention, swelling is prevented by a modification of type 304, 316, 321, or 12 K 72HV commercial steels. They consist mainly of Fe, Cr, and Ni in a ratio determined by a temary diagram. They may also contain 1.8 to 2.3% by weight of Mo and a fraction of Si (0.7 to 2% by weight) and Ti(0.10 to 0.5% by weight) to prevent cavity formation. They are structurally modified by cold working. (IHOE) [de

  2. Volatilization from PCA steel alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hagrman, D.L.; Smolik, G.R.; McCarthy, K.A.; Petti, D.A.

    1996-08-01

    The mobilizations of key components from Primary Candidate Alloy (PCA) steel alloy have been measured with laboratory-scale experiments. The experiments indicate most of the mobilization from PCA steel is due to oxide formation and spalling but that the spalled particles are large enough to settle rapidly. Based on the experiments, models for the volatization of iron, manganese, and cobalt from PCA steel in steam and molybdenum from PCA steel in air have been derived.

  3. The effects of the local fracture stress and carbides on the cleavage fracture characteristics of Mn-Mo-Ni low alloy steels in the transition region

    International Nuclear Information System (INIS)

    Yang, Won Jon; Huh, Moo Young; Roh, Sung Joo; Lee, Bong Sang; Oh, Yong Jun; Hong, Jun Hwa

    2000-01-01

    In the ductile-brittle transition temperature region of SA508 C1.3 Mn-Mo-Ni low alloy steels, the relationship of the local fracture stress and carbides influencing the cleavage fracture behavior was investigated. Based on the ASTM E1921-97 standard method, the reference transition temperatures were determined by three point bending fracture toughness tests. A local fracture stress σ f * , was determined from a theoretical stress distribution in front of crack tip using the cleavage initiation distance measured in each fractured specimen surface. The local fracture stress values showed a strong relationship with toughness characteristics of the materials and those were larger in the materials of smaller carbide size. Quantitative analysis of carbides showed that carbides larger than a certain size are mainly responsible for the cleavage fracture in the ductile-brittle transition temperature region. (author)

  4. Plating on stainless steel alloys

    International Nuclear Information System (INIS)

    Dini, J.W.; Johnson, H.R.

    1981-01-01

    Quantitative adhesion data are presented for a variety of electroplated stainless steel type alloys. Results show that excellent adhesion can be obtained by using a Wood's nickel strike or a sulfamate nickel strike prior to final plating. Specimens plated after Wood's nickel striking failed in the deposit rather than at the interface between the substrate and the coating. Flyer plate quantitative tests showed that use of anodic treatment in sulfuric acid prior to Wood's nickel striking even further improved adhesion. In contrast activation of stainless steels by immersion or cathodic treatment in hydrochloric acid resulted in very reduced bond strengths with failure always occurring at the interface between the coating and substrate

  5. Development of advanced low alloy steel for nuclear RPV

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H. C.; Shin, K. S.; Lee, S. H.; Lee, B. J. [Seoul National Univ., Seoul (Korea)

    2000-04-01

    Low carbon low alloy steels are used in nuclear power plants as pressure vessel, steam generator, etc. Nuclear pressure vessel material requires good combination of strength/ toughness, good weldability and high resistance to neutron irradiation and corrosion fatigue. For SA508III steels, most widely used in the production of nuclear power plant, attaining toughness is more difficult than strength. When taking into account the loss of toughness due to neutron irradiation, attaining as low transition temperature as possible prior to operation is a critical task in the production of nuclear pressure vessels. In the present study, we investigated detrimental microstructural features of SA508III steels to toughness, then alloy design directions to achieve improved mechanical properties were devised. The next step of alloy design was determined based on phase equilibrium thermodynamics and obtained results. Low carbon low alloy steels having low transition temperatures with enough strength and hardenability were developed. Microstructure and mechanical properties of HAZ of SA508III steels and alloy designed steels were investigated. 22 refs., 147 figs., 38 tabs. (Author)

  6. Stable carbides in transition metal alloys

    International Nuclear Information System (INIS)

    Piotrkowski, R.

    1991-01-01

    In the present work different techniques were employed for the identification of stable carbides in two sets of transition metal alloys of wide technological application: a set of three high alloy M2 type steels in which W and/or Mo were total or partially replaced by Nb, and a Zr-2.5 Nb alloy. The M2 steel is a high speed steel worldwide used and the Zr-2.5 Nb alloy is the base material for the pressure tubes in the CANDU type nuclear reactors. The stability of carbide was studied in the frame of Goldschmidt's theory of interstitial alloys. The identification of stable carbides in steels was performed by determining their metallic composition with an energy analyzer attached to the scanning electron microscope (SEM). By these means typical carbides of the M2 steel, MC and M 6 C, were found. Moreover, the spatial and size distribution of carbide particles were determined after different heat treatments, and both microstructure and microhardness were correlated with the appearance of the secondary hardening phenomenon. In the Zr-Nb alloy a study of the α and β phases present after different heat treatments was performed with optical and SEM metallographic techniques, with the guide of Abriata and Bolcich phase diagram. The α-β interphase boundaries were characterized as short circuits for diffusion with radiotracer techniques and applying Fisher-Bondy-Martin model. The precipitation of carbides was promoted by heat treatments that produced first the C diffusion into the samples at high temperatures (β phase), and then the precipitation of carbide particles at lower temperature (α phase or (α+β)) two phase field. The precipitated carbides were identified as (Zr, Nb)C 1-x with SEM, electron microprobe and X-ray diffraction techniques. (Author) [es

  7. Microstructure of the Transitional Area of the Connection of a High-temperature Ni-based Brazing Alloy and Stainless Steel AISI 321 (X6CrNiTi 18–10

    Directory of Open Access Journals (Sweden)

    R. Augustin

    2010-01-01

    Full Text Available This paper presents a detailed examination of the structure of the transitional area between a brazing alloy and the parent material, the dimensions of the diffusion zones that are created, and the influence on them of a change in the brazing parameters. Connections between Ni-based brazing alloys (NI 102 with a small content of B and AISI 321 stainless steel (X6CrNiTi 18–10 were created in a vacuum (10−2 Pa at various brazing temperatures and for various holding times at the brazing temperature. Various specimens were tested. First, the brazing alloys were wetted and the dependence of the wetting on the brazing parameters was assessed. Then a chemical microanalysis was made of the interface between the brazing alloy and the parent material. The individual diffusion zones were identified on pictures from a light microscope and REM, and their dimensions, together with their dependence on the brazing parameters, were determined.

  8. Comparison of SA508 Gr.3 and SA508 Gr.4N Low Alloy Steels for Reactor Pressure Vessel Steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Chul; Lee, B. S

    2009-12-15

    The microstructural characteristics and mechanical properties of SA508 Gr.3 Mn-Mo-Ni low alloy steel and SA508 Gr.4N Ni-Mo-Cr low alloy steel were investigated. The differences in the stable phases between these two low alloy steels were evaluated by means of a thermodynamic calculation using ThermoCalc. They were then compared to microstructural features and correlated with mechanical properties. Mn-Mo-Ni low alloy steel shows the upper bainite structure which has the coarse cementite in the lath boundaries. However, Ni-Mo-Cr low alloy steel shows the mixture of lower bainite and tempered martensite structure that homogeneously precipitates the small carbides such as M{sub 23}C{sub 6} and M{sub 7}C{sub 3} due to an increase of hardenability and Cr addition. In the mechanical properties, Ni-Mo-Cr low alloy steel has higher strength and toughness than Mn-Mo-Ni low alloy steel. Ni and Cr additions increase the strength by solid solution hardening. Besides, microstructural changes from upper bainite to tempered martensite improve the strength of the low alloy steel by grain refining effect. And the changes in the precipitation behavior by Cr addition improve the ductile-brittle transition behavior along with a toughening effect of Ni addition.

  9. Nickel alloys and high-alloyed special stainless steels. Properties, manufacturing, applications. 4. compl. rev. ed.

    International Nuclear Information System (INIS)

    Heubner, Ulrich; Kloewer, Jutta; Alves, Helena; Behrens, Rainer; Schindler, Claudius; Wahl, Volker; Wolf, Martin

    2012-01-01

    This book contains the following eight topics: 1. Nickel alloys and high-alloy special stainless steels - Material overview and metallurgical principles (U. Heubner); 2. Corrosion resistance of nickel alloys and high-alloy special stainless steels (U. Heubner); 3. Welding of nickel alloys and high-alloy special stainless steels (T. Hoffmann, M. Wolf); 4. High-temperature materials for industrial plant construction (J. Kloewer); 5. Nickel alloys and high-alloy special stainless steels as hot roll clad composites-a cost-effective alternative (C. Schindler); 6. Selected examples of the use of nickel alloys and high-alloy special stainless steels in chemical plants (H. Alves); 7. The use of nickel alloys and stainless steels in environmental engineering (V. Wahl); 8: Nickel alloys and high-alloy special stainless steels for the oil and gas industry (R. Behrens).

  10. Fracture toughness of irradiated stainless steel alloys

    International Nuclear Information System (INIS)

    Mills, W.J.

    1986-01-01

    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 427 0 C 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/m 2 ; the weld exhibited a saturation level of 11 kJ/m 2 . 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

  11. Nitrogen-alloyed martensitic steels

    International Nuclear Information System (INIS)

    Berns, H.

    1988-01-01

    A report is presented on initial results with pressure-nitrided martensitic steels. In heat-resistant steels, thermal stability and toughness are raised by nitrogen. In cold work steel, there is a more favourable corrosion behaviour. (orig./MM) [de

  12. Boron Steel: An Alternative for Costlier Nickel and Molybdenum Alloyed Steel for Transmission Gears

    Directory of Open Access Journals (Sweden)

    A. Verma

    2010-06-01

    Full Text Available Case Carburized (CC low carbon steels containing Ni, Cr and Mo alloying elements are widely used for transmission gears in automobile, as it possesses desired mechanical properties. In order to cut cost and save scarce materials like Ni and Mo for strategic applications, steel alloyed with Boron has been developed, which gives properties comparable to Ni-Cr-Mo alloyed steel. In the process of steel development, care was taken to ensure precipitation of boron which results in precipitation hardening. The characterization of the developed boron steel had exhibited properties comparable to Ni-Cr-Mo alloyed steel and superior to conventional boron steel.

  13. Laser surface alloying of aluminium-transition metal alloys

    International Nuclear Information System (INIS)

    Almeida, A.; Vilar, R.

    1998-01-01

    Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM) alloys. Cr and Mo are particularly interesting alloying elements to produce stable high-strength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO 2 laser . This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloy, over the last years. (Author) 16 refs

  14. Applications of nitrogen-alloyed stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Sundvall, J.; Olsson, J. [Avesta Sheffield AB (Sweden); Holmberg, B. [Avesta Welding AB (Sweden)

    1999-07-01

    A selected number of applications for different types of nitrogen-alloyed stainless steels are described. The applications and grades are based on how nitrogen improves different properties. Conventional austenitic grades of type 304 and 316 can be alloyed with nitrogen to increase the strength and to maintain the austenite stability after cold deformation when exposed to cryogenic temperatures. Such examples are presented. The addition of nitrogen to duplex grades of stainless steel such as 2205 improves the pitting resistance, among other things, and also enables faster reformation of the austenite in the heat affected zone. This means that heavy plate can be welded without pre-heating or post-weld heating. Such applications are covered. Modern highly alloyed austenitic stainless steels almost always contain nitrogen and all reasons for this are covered, i.e. to stabilise the austenite, to increase the strength, and to improve the pitting resistance. The increased strength is the characteristic exemplified the least, since the higher strength of duplex grades is well known, but examples on austenite stability and improved pitting resistance are presented. (orig.)

  15. Effect of solute grain boundary segregation and hardness on the ductile-to-brittle transition for a Cr-Mo low-alloy steel

    International Nuclear Information System (INIS)

    Shen, D.-D.; Song, S.-H.; Yuan, Z.-X.; Weng, L.-Q.

    2005-01-01

    Combined solute grain boundary segregation and hardness effect on the ductile-to-brittle transition is examined for a P-doped 2.25Cr-1Mo steel by means of Auger electron spectroscopy (AES) in conjunction with hardness measurements, Charpy impact tests and scanning electron microscopy (SEM). During ageing at 540 deg. C after water quenching from 980 deg. C, the segregation of phosphorus, molybdenum and chromium increases and the hardness decreases with increasing ageing time. The ductile-to-brittle transition temperature (DBTT) increases with increasing phosphorus segregation and decreases with decreasing hardness. The phosphorus segregation effect is dominant until 100 h ageing and after that the hardness effect becomes dominant, making the DBTT decrease with further increasing ageing time although the segregation of phosphorus still increases strongly. The segregation of molybdenum has some effect on the DBTT decrease

  16. Strengthening Hadfield steel welds by nitrogen alloying

    International Nuclear Information System (INIS)

    Efstathiou, C.; Sehitoglu, H.

    2009-01-01

    Strengthening Hadfield steel weld repairs by introducing nitrogen into the weld region was proven to be feasible via two welding techniques. The first technique required a pure Hadfield steel filler material to be diffusion treated in a high pressure nitrogen gas environment, and subsequently used during tungsten inert gas welding with a pure argon shielding gas. The second technique used a Hadfield steel filler material, and a 10% nitrogen containing argon shielding gas during tungsten inert gas welding. Both techniques increased the yield strength, the hardening rate, and the ultimate strength of the weld region. Using optical microscopy, scanning electron microscopy, and Auger spectroscopy, we determined that the increased strength of the weld region resulted from a combination of nitrogen alloying and microstructural refinement

  17. Athermal kinetics in low alloy steels

    International Nuclear Information System (INIS)

    Leiva, Jorge A Vega; Valencia Morales, Eduardo; Villar Cociña, Ernesto; Hernández Ruiz, Jesús; Donis, Carlos

    2008-01-01

    Athermic analyses for the kinetic study of the reactions in the solid state are preferred because they consume much less experimental work time than the isothermal tests, and lead to more accurate calculations of the energies of activation of reactions that have occurred. In the present work are required conditions where you can apply the equation of speed of an athermal reaction in a low alloy in solid steel. From records of steel (AISI 1050) dilatometric triples were calculated kinetics (E, Ko, n) that characterize the reactions that occurred during the tempering of samples using different methods of iso conversion, one of which is a new modification of the method of Friedman. Also, has shown that during the formation of carbide Epsilon in the first stage of the tempering has occurred a saturation of sites, which validates the use of some methods. Finally, the orders of the reactions occurred during tempering of steel studied treatment are calculated.

  18. Progress in the development of niobium alloyed high speed steel

    International Nuclear Information System (INIS)

    Guimaraes, J.R.C.

    1987-01-01

    The development of economy-grades of niobium alloyed high speed steel is described. Both the metallurgical concepts behind the steel design and the results of performance tests are presented. (Author) [pt

  19. Silicate enamel for alloyed steel

    International Nuclear Information System (INIS)

    Ket'ko, K.K.

    1976-01-01

    The use of silicate enamels in the metallurgical industry is discussed. Presented are the composition and the physico-chemical properties of the silicate enamel developed at the factory 'Krasnyj Oktyabr'. This enamel can be used in the working conditions both in the liquid and the solid state. In so doing the enamel is melted at 1250 to 1300 deg C, granulated and then reduced to a fraction of 0.3 to 0.5 mm. The greatest homogeneity is afforded by a granulated enamel. The trials have shown that the conversion of the test ingots melted under a layer of enamel leads to the smaller number of the ingots rejected for surface defect reasons and the lower metal consumption for slab cleaning. The cost of the silicate enamel is somewhat higher than that of synthetic slags but its application to the melting of stainless steels is still economically beneficial and technologically reasonable. Preliminary calculations only for steel EhI4IEh have revealed that the use of this enamel saves annually over 360000 roubles [ru

  20. Crack stability analysis of low alloy steel primary coolant pipe

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T.; Kameyama, M. [Kansai Electric Power Company, Osaka (Japan); Urabe, Y. [Mitsubishi Heavy Industries, Ltd., Takasago (Japan)] [and others

    1997-04-01

    At present, cast duplex stainless steel has been used for the primary coolant piping of PWRs in Japan and joints of dissimilar material have been applied for welding to reactor vessels and steam generators. For the primary coolant piping of the next APWR plants, application of low alloy steel that results in designing main loops with the same material is being studied. It means that there is no need to weld low alloy steel with stainless steel and that makes it possible to reduce the welding length. Attenuation of Ultra Sonic Wave Intensity is lower for low alloy steel than for stainless steel and they have advantageous inspection characteristics. In addition to that, the thermal expansion rate is smaller for low alloy steel than for stainless steel. In consideration of the above features of low alloy steel, the overall reliability of primary coolant piping is expected to be improved. Therefore, for the evaluation of crack stability of low alloy steel piping to be applied for primary loops, elastic-plastic future mechanics analysis was performed by means of a three-dimensioned FEM. The evaluation results for the low alloy steel pipings show that cracks will not grow into unstable fractures under maximum design load conditions, even when such a circumferential crack is assumed to be 6 times the size of the wall thickness.

  1. Niobium in steels and alloys

    International Nuclear Information System (INIS)

    Lyakishev, N.P.; Tulin, N.A.; Pliner, Y.L.

    1984-01-01

    Data are presented on the reserves and processing of niobium raw materials followed by brief review of the current status and long-range trends in the commercial usage of niobium and its compounds. A survey is made of the physical properties of niobium and its chemical reactions with elements of direct concern in the manufacture of ferroalloys, quality steels and other products. Niobium minerals and ores, along with common ore processing practices are described briefly. Attention is paid to Brazilian niobium ores, and to the Araxa deposit specifically. Some emphasis has been given to methods of processing lean niobium ores not easily amenable to simple concentration. A systematic review is presented of the techniques used in the production of niobium ferroalloys. (E.G.) [pt

  2. 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.

  3. Stress corrosion in low alloy steels

    International Nuclear Information System (INIS)

    Scott, P.M.; Tice, D.R.

    1988-01-01

    The main variables affecting environmentally induced crack initiation and growth in low alloy pressure vessel steels exposed to high temperature aqueous environments are reviewed. Considerable background knowledge is available on many of the important factors such as stress, crack tip stress intensity, strain rate, steel composition and microstructure, environmental temperature, chemistry, oxidising capacity and flowrate. This information is also compared with known plant incidents of environmentally induced or assisted cracking. Certain gaps in these data and their interpretation are judged to remain particularly in the case where oxygenated water is present. These arise predominantly in the definition of margins available on plant water chemistry specifications before risk of environmentally induced cracking becomes unacceptable and in quantifying the beneficial effect of high water flowrates. (orig.)

  4. Stress corrosion in low alloy steels

    International Nuclear Information System (INIS)

    Scott, P.M.; Tice, D.R.

    1990-01-01

    The main variables affecting environmentally induced crack initiation and growth in low alloy pressure vessel steels exposed to high temperature aqueous environments are reviewed. Considerable background knowledge is available on many of the important factors such as stress, crack tip stress intensity, strain rate, steel composition and microstructure, environmental temperature, chemistry, oxidising capacity and flowrate. This information is also compared with known plant incidents of environmentally induced or assisted cracking. Certain gaps in these data and their interpretation are judged to remain particularly in the case where oxygenated water is present. These arise predominantly in the definition of margins available on plant water chemistry specifications before risk of environmentally incuced cracking becomes unacceptable and in quantifying the beneficial effect of high water flowrates. (orig.)

  5. Stress corrosion of low alloy steel forgings

    International Nuclear Information System (INIS)

    Thornton, D.V.; Mould, P.B.; Patrick, E.C.

    1976-01-01

    The catastrophic failure of a steam turbine rotor disc at Hinkley Point 'A' Power station was shown to have been caused by the growth of a stress corrosion crack to critical dimensions. This failure has promoted great interest in the stress corrosion susceptibility of medium strength low alloy steel forgings in steam environments. Consequently, initiation and growth of stress corrosion cracks of typical disc steels have been investigated in steam and also in water at 95 0 C. Cracking has been shown to occur, predominantly in an intergranular manner, with growth rates of between 10 -9 and 10 -7 mm sec. -1 . It is observed that corrosion pitting and oxide penetration prior to the establishment of a stress corrosion crack in the plain samples. (author)

  6. Stainless steel-zirconium alloy waste forms

    International Nuclear Information System (INIS)

    McDeavitt, S.M.; Abraham, D.P.; Keiser, D.D. Jr.; Park, J.Y.

    1996-01-01

    An electrometallurgical treatment process has been developed by Argonne National Laboratory to convert various types of spent nuclear fuels into stable storage forms and waste forms for repository disposal. The first application of this process will be to treat spent fuel alloys from the Experimental Breeder Reactor-II. Three distinct product streams emanate from the electrorefining process: (1) refined uranium; (2) fission products and actinides extracted from the electrolyte salt that are processed into a mineral waste form; and (3) metallic wastes left behind at the completion of the electrorefining step. The third product stream (i.e., the metal waste stream) is the subject of this paper. The metal waste stream contains components of the chopped spent fuel that are unaffected by the electrorefining process because of their electrochemically ''noble'' nature; this includes the cladding hulls, noble metal fission products (NMFP), and, in specific cases, zirconium from metal fuel alloys. The selected method for the consolidation and stabilization of the metal waste stream is melting and casting into a uniform, corrosion-resistant alloy. The waste form casting process will be carried out in a controlled-atmosphere furnace at high temperatures with a molten salt flux. Spent fuels with both stainless steel and Zircaloy cladding are being evaluated for treatment; thus, stainless steel-rich and Zircaloy-rich waste forms are being developed. Although the primary disposition option for the actinides is the mineral waste form, the concept of incorporating the TRU-bearing product into the metal waste form has enough potential to warrant investigation

  7. Structure and radiation induced swelling of steels and alloys

    International Nuclear Information System (INIS)

    Parshin, A.M.

    1983-01-01

    Regularities of vacancy void formation and radiation induced swelling of austenitic chromium-nickel steels and alloyse ferritic steels as well as titanium α-alloys under radiation by light and heavy ions and neutrons are considered. Possible methods for preparation of alloys with increased resistance to radiation swelling are described. Accounting for investigations into ferritic steels and α-alloys of titanium the basic way of weakening vacancy smelling is development of continuous homogeneous decomposition of solid solution using alloying with vividly expressed incubation period at a certain volumetric dilatation as well as decompositions of the type of ordering, K-state, lamination of solid solutions, etc. Additional alloying of solid solutions is also shown to be necessary for increasing recrystallization temperature of cold-deformed steel

  8. Mechanical behaviour of Zn-Fe alloy coated mild steel

    International Nuclear Information System (INIS)

    Panagopoulos, C.N.; Georgiou, E.P.; Agathocleous, P.E.; Giannakopoulos, K.I.

    2009-01-01

    Zinc alloy coatings containing various amounts of Fe were deposited by electrodeposition technique on a mild steel substrate. The concentration of Fe in the produced alloy coatings ranged from 0 to 14 wt.%, whereas the thickness of the coatings was about 50 μm. Structural and metallurgical characterization of the produced coatings was performed with the aid of X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) techniques. This study aims in investigating the mechanical behaviour of Zn-Fe coated mild steel specimens, as no research investigation concerning the tensile behaviour of Zn alloy coated ferrous alloys has been reported in the past. The experimental results indicated that the ultimate tensile strength of the Zn-Fe coated mild steel was lower than the bare mild steel. In addition, the ductility of the Zn-Fe coated mild steel was found to decrease significantly with increasing Fe content in the coating.

  9. Low alloy steel versus ADI – differences and similarities

    Directory of Open Access Journals (Sweden)

    A. Krzyńska

    2009-01-01

    Full Text Available The results of comparison between the microstructure of selected bainitic low alloy steel and austempered ductile iron ADI are presented. The aim of the comparison was to find out differences and similarities existing in these iron carbon commercial alloys. In this paper our own results on ADI structure and literature data were used. It follows from discussion presented here that both microstructure and properties of ADI are very close that which are observed in low alloy carbon steel. Moreover, we suggest that there is no so doubt to treat ADI mechanical properties as steel containing nodular inclusions of graphite.

  10. Development of niobium alloy/stainless steel joint by friction welding, (1)

    International Nuclear Information System (INIS)

    Kikuchi, Taiji; Kawamura, Hiroshi.

    1988-08-01

    The niobium alloy and stainless steel have been jointed by the nicrobrazing method generally. However the strength of the jointed part is weaker than that of the mother material. Therefore we developed the niobium alloy(Nb-1 % Zr)/stainless steel(SUS 304) transition joint by the friction welding method. As the tests for the development. We conducted the mechanical tests (tensile test at room temperature, 300 deg C, 500 deg C and 700 deg C, torsion fatigue test and burst test), metallographical observation and electron prove X-ray microanalysis observation. Those tests proved jointed part by the friction welding had enough properties for general uses. (author)

  11. Corrosion processes of alloyed steels in salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kienzler, Bernhard [Karlsruher Institut fuer Technologie (KIT), Eggenstein-Leopoldshafen (Germany). Institut fuer Nukleare Entsorgung

    2018-02-15

    A summary is given of the corrosion experiments with alloyed Cr-Ni steels in salt solutions performed at Research Centre Karlsruhe (today KIT), Institute for Nuclear Waste Disposal (INE) in the period between 1980 and 2004. Alloyed steels show significantly lower general corrosion in comparison to carbon steels. However, especially in salt brines the protective Cr oxide layers on the surfaces of these steels are disturbed and localized corrosion takes place. Data on general corrosion rates, and findings of pitting, crevice and stress corrosion cracking are presented.

  12. Comparison of fracture properties for two types of low alloy steels

    International Nuclear Information System (INIS)

    Nasreldin, A.M.

    2004-01-01

    The fracture properties of two types of low alloy steels used in the pressure vessel and boilers industry were determined. The first type was the steel A533-B which comprised a fully bainitic microstructure. The second one was the C-Mn steel which consisted of ferritic-pearlitic microstructure. The following fracture properties were determined using instrumented impact testing: the total fracture energy, the crack initiation and propagation energies, the brittleness transition temperature and the local fracture stress. The steel A533-B showed better fracture properties at high testing temperatures, while the C-Mn steel displayed higher resistance to brittle fracture at low testing temperatures. The results were discussed in relation to the difference in microstructure and fracture surface morphology for both steels

  13. Plastic deformation and fracture behaviors of nitrogen-alloyed austenitic stainless steels

    International Nuclear Information System (INIS)

    Wang Songtao; Yang Ke; Shan Yiyin; Li Laifeng

    2008-01-01

    The plastic deformation and fracture behaviors of two nitrogen-alloyed austenitic stainless steels, 316LN and a high nitrogen steel (Fe-Cr-Mn-0.66% N), were investigated by tensile test and Charpy impact test in a temperature range from 77 to 293 K. The Fe-Cr-Mn-N steel showed ductile-to-brittle transition (DBT) behavior, but not for the 316LN steel. X-ray diffraction (XRD) confirmed that the strain-induced martensite occurred in the 316LN steel, but no such transformation in the Fe-Cr-Mn-N steel. Tensile tests showed that the temperature dependences of the yield strength for the two steels were almost the same. The ultimate tensile strength of the Fe-Cr-Mn-N steel displayed less significant temperature dependence than that of the 316LN steel. The strain-hardening exponent increased for the 316LN steel, but decreased for the Fe-Cr-Mn-N steel, with decreasing temperature. Based on the experimental results and the analyses, a modified scheme was proposed to explain the fracture behaviors of austenitic stainless steels

  14. Influence of alloying elements and density on aqueous corrosion behaviour of some sintered low alloy steels

    International Nuclear Information System (INIS)

    Kandavel, T.K.; Chandramouli, R.; Karthikeyan, P.

    2012-01-01

    Highlights: ► Corrosion of low alloy P/M steels under HCl acid pickling environment has been studied. ► Influence of density, strain and alloying elements on the rate of corrosion of the steels has been investigated. ► Residual porosity has significant effect on acid corrosion. ► Addition of the alloying elements Cu, Mo and Ti reduces the corrosion rate significantly. ► Carbide forming elements Mo and Ti improve further the resistance of the steels to aqueous corrosion. -- Abstract: Low alloy steels produced through powder metallurgy route of sintering followed by forging are promising candidate materials for high strength small components. Porosity in such steels poses a real challenge during acid pickling treatment, which is one of the processing steps during manufacturing. The present research work attempts to investigate the mechanism underlying the acid corrosion behaviour of some sintered low alloy steels under induced acid pickling conditions. Sintered-forged low alloy steel samples containing molybdenum (Mo), copper (Cu) and titanium (Ti) were subjected to aqueous corrosion attack by immersing the samples in 18% HCl (Hydrochloric acid) solution for 25 h. Sample weight loss and Fe (Iron) loss were estimated for the corroded samples. The morphology of the corroded surfaces was studied through metallography and scanning electron microscopy. Higher porosity alloys underwent enhanced corrosion rates. Both corrosion rate and iron loss are found to decrease linearly with reduction in porosity in all cases of the alloys. The alloying elements Mo, Ti and Cu, when added in combination, have played a complementary role in the reduction of corrosion rate by almost one order of magnitude compared to unalloyed steel. Presence of carbides of the carbide forming elements Mo and Ti played a positive role on the corrosion behaviour of the low alloy steels.

  15. Abrasive Wear of Alloyed Cast Steels Applied for Heavy Machinery

    Directory of Open Access Journals (Sweden)

    Studnicki A.

    2015-03-01

    Full Text Available In the paper the results and analysis of abrasive wear studies were shown for two grades of cast steels: low-alloyed cast steel applied for heavy machinery parts such as housing, covers etc. and chromium cast steels applied for kinetic nodes of pin-sleeve type. Studies were performed using the modified in Department of Foundry pin-on-disc method.

  16. Properties of Mo-alloyed sintered manganese steels

    International Nuclear Information System (INIS)

    Romanski, A.; Cias, A.

    1998-01-01

    Sintered alloy steels are needed for mostly PM structural parts. Powder metallurgy techniques provide a means of fabricating high quality steel parts with tailored mechanical properties. It is now possible to produce sintered steel parts with properties equal to an even superior to those of parts made by more traditional routes. Challenges arise both with the material selection and component fabrication. This work outlines the processing for high performance structural application. (author)

  17. Phase stability of transition metals and alloys

    International Nuclear Information System (INIS)

    Hixson, R.S.; Schiferl, D.; Wills, J.M.; Hill, M.A.

    1997-01-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project was focused on resolving unexplained differences in calculated and measured phase transition pressures in transition metals. Part of the approach was to do new, higher accuracy calculations of transmission pressures for group 4B and group 6B metals. Theory indicates that the transition pressures for these baseline metals should change if alloyed with a d-electron donor metal, and calculations done using the Local Density Approximation (LDA) and the Virtual Crystal Approximation (VCA) indicate that this is true. Alloy systems were calculated for Ti, Zr and Hf based alloys with various solute concentrations. The second part of the program was to do new Diamond Anvil Cell (DAC) measurements to experimentally verify calculational results. Alloys were prepared for these systems with grain size suitable for Diamond Anvil Cell experiments. Experiments were done on pure Ti as well as Ti-V and Ti-Ta alloys. Measuring unambiguous transition pressures for these systems proved difficult, but a new technique developed yielded good results

  18. Simulation of Structural Transformations in Heating of Alloy Steel

    Science.gov (United States)

    Kurkin, A. S.; Makarov, E. L.; Kurkin, A. B.; Rubtsov, D. E.; Rubtsov, M. E.

    2017-07-01

    Amathematical model for computer simulation of structural transformations in an alloy steel under the conditions of the thermal cycle of multipass welding is presented. The austenitic transformation under the heating and the processes of decomposition of bainite and martensite under repeated heating are considered. Amethod for determining the necessary temperature-time parameters of the model from the chemical composition of the steel is described. Published data are processed and the results used to derive regression models of the temperature ranges and parameters of transformation kinetics of alloy steels. The method developed is used in computer simulation of the process of multipass welding of pipes by the finite-element method.

  19. Chemical heat treatment of low alloyed maraging steels

    Energy Technology Data Exchange (ETDEWEB)

    Malinov, L S; Korotich, I K [Zhdanovskij Metallurgicheskij Inst. (Ukrainian SSR)

    1979-09-01

    The investigation concerned the nitriding, cementation, chromizing, borating of economically alloyed maraging grade 04Kh2N5MFYu steel. The investigated methods of chemothermal treatment were found to considerably increase the hardness of the surface layer of the maraging steel. The high tempering of the grade 04Kh2N5MFYu cemented and hardened steel was found to produce secondary hardening. On chromizing, the diffusion layer is an alloyed ferrite which strengthens because of the dispersion hardening on ageing. The formation of the plastic low-carbon martensite at relatively small cooling rates greatly decreases the tendency of the boride layer to cracking.

  20. Parallel between steels alloyed with chrome-nickel and Fe-Mn-Al-C steels, in their response to fracture and wear (Review)

    International Nuclear Information System (INIS)

    Ramos, J; Perez, G.A

    2008-01-01

    The big worldwide demand for chrome-nickel alloy steels ('conventional steel') leads to the need for advanced materials for applications in different engineering systems that operate at high temperatures and in aggressive environmental conditions, favoring research and development in alternate alloys. In this technological race in search of these new materials, the FeMnAlC alloys ('new steels') have attracted attention for their excellent mechanical and tribological properties as well as for their good performance in corrosive-oxide environments, which make them similar to conventional steel. There are two important similarities between these two steels. First, an agent that causes the passive film to become stainless appears in both steels: chrome in the conventional steel, and aluminum in the FeMnAl alloy. The second similarity is that a stabilizing agent of the austenitic phase (FCC) appears in both, so that excellent mechanical properties can be obtained: nickel in the conventional steel, and manganese in the FeMnAl alloy. In certain sectors, such as aeronautics, conventional steel is rarely used because it is a very heavy material. This conventional steel is almost three times heavier that aluminum (7.85/2.7). Two advantages that the new FeMnAIC steels have compared to the conventional steels are that they are about 13% lighter in weight and they are less expensive. The FeMnAl also have excellent mechanical properties and good corrosion-oxidation resistance, which generates big expectations for their application in a broad scientific spectrum. This work reports the state of the information currently available about FeMnAlC alloys, comparing the mechanical and tribological behaviors of conventional alloy steels with chrome and nickel alloys, specifying the scopes of their application. A condition that favors the steels' fragility is the high speed of deformation and impact, where the FCC crystalline structure materials do not have a fragile ductile transition

  1. Metal dusting of low alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Grabke, H.J. (Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)); Bracho-Troconis, C.B. (Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)); Mueller-Lorenz, E.M. (Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany))

    1994-04-01

    The metal dusting of two low alloy steels was investigated at 475 C in flowing CO-H[sub 2]-H[sub 2]O mixtures at atmospheric pressure with a[sub C] > 1. The reaction sequence comprises: (1) oversaturation with C, formation of cementite and its decomposition to metal particles and carbon, and (2) additional carbon deposition on the metal particles from the atmosphere. The metal wastage rate r[sub 1] was determined by analysis of the corrosion product after exposures, this rate is constant with time and virtually independent of the environment. The carbon deposition from the atmosphere was determined by thermogravimetry, its rate r[sub 2] increases linearly with time, which can be explained by the catalytic action of the metal particles - periodic changes are superposed. The rate of carbon deposition r[sub 2] is proportional to the carbon activity in the atmosphere. The metal dusting could not be suppressed by increasing the oxygen activity or preoxidation, even if magnetite should be stable. Addition of H[sub 2]S, however, effectively suppresses the attack. (orig.)

  2. Milling and Drilling Evaluation of Stainless Steel Powder Metallurgy Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lazarus, L.J.

    2001-12-10

    Near-net-shape components can be made with powder metallurgy (PM) processes. Only secondary operations such as milling and drilling are required to complete these components. In the past and currently production components are made from powder metallurgy (PM) stainless steel alloys. process engineers are unfamiliar with the difference in machining properties of wrought versus PM alloys and have had to make parts to develop the machining parameters. Design engineers are not generally aware that some PM alloy variations can be furnished with machining additives that greatly increase tool life. Specimens from a MANTEC PM alloy property study were made available. This study was undertaken to determine the machining properties of a number of stainless steel wrought and PM alloys under the same conditions so that comparisons of their machining properties could be made and relative tool life determined.

  3. Effect of notch and alloying on steel properties during extension

    International Nuclear Information System (INIS)

    Vinokur, B.B.; Pilyushenko, U.L.; Kasatkin, O.G.

    1985-01-01

    A study was made on change of strength and plastic characteristics during extension of notched steel samples of 15 compositions containing often-used alloying elements in various amounts and combinations. The notch causes increase of strength and decrease of plastic properties of structural steels during extension. The most pronounced change of properties takes place for the notched sample with expansion angle close to 180 deg. Reduction of notch expansion angle below 150 deg causes slower decrease of the rate of property change. Nickel alloying and vanadium, titanium microalloying assist the improvement of steel plasticity despite the increase of strength properties. Introduction of these elements in steel compensate partially for the negative notch effect. Alloying by silicon, molybdenum and tungsten results in steel strengthening and chromium alloying causes some loss of strength. Manse, chromium, silicon, molybdenum and tungsten cause decrease of plasticity, which intensifies the negative notch effect. When determining concentration ranges of carbon and alloying elements within the limits of quality composition it is necessary to consider both technology and possibility of sufficient change of properties especially in the case of stress concentrator presence in structures

  4. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.

    1998-04-01

    Full Text Available Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM alloys. Cr and Mo are particularly interesting alloying elements to produce stable highstrength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO2 laser. This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloys, over the last years.

    En el presente trabajo se estudia la aleación superficial mediante láser de aluminio con metales de transición. El cromo y el molibdeno son particularmente interesantes porque producen aleaciones de alta resistencia y por el bajo coeficiente de difusión y solución sólida en aluminio. Para producir estas aleaciones se ha seguido un procedimiento desarrollado en dos partes. En primer lugar, el material se alea usando una baja velocidad de procesado y en segundo lugar la estructura se modifica mediante un refinamiento posterior. Este procedimiento se ha empleado en la producción de aleaciones Al-Cr, Al-Mo y Al-Nb mediante aleación con láser de CO2 de polvos de Cr, Mo o Nb en aluminio y la aleación 7175. Este trabajo es una revisión del desarrollado en el Instituto Superior Técnico de Lisboa en los últimos años.

  5. The structure of the alphinizing coat on alloy steels

    Directory of Open Access Journals (Sweden)

    S. Pietrowski

    2008-12-01

    Full Text Available In this paper results of the structure of the coat alphinizing in AlSi5 silumin on alloy steels: acid-proof 1H18N9T (X6CrNiTi18-10 and high speed SW18 (HS18-0-1 were presented. The temperature of the alphinizing bath was amounts to750±5°C, and immersion time of the element τ = 180s. It was shown, that there is the different “g” coat thickness on testing steels. On the 1H18N9T steel it amounts to g = 52μm, and on the SW18 steel – g = 203μm. Regardless of a grade of testing alloy steels the coat consist of three layers with diversified phasic structure. There is different chemical composition of coat layers on testing steels. The first layer from the base consist of AlFe phase containing alloy addictions of steels: Cr and Ni (1H18N9T and W, V and Cr (SW18. On this layer crystallize the second layer of intermetallic phases. It is the phase containing the main alloy addiction of steels: AlFeCr (1H18N9T and AlFeW (SW18. The last, outside layer consist of silumin containing AlFeNi intermetallic phases on the 1H18N9T steel and AlFeW on the SW18 steel. Regardless of the grade of testing steels there is Si element in all layers of the coat. There are morphological differences in tested layers. The second layer (AlFeW phase inside the coat on the SW18 steel consist of faced crystals growing into in outside silumin layer. On the 1H18N9T steel a boundary between transient and outside layer is more uniform. Free separations of intermetallic phases inside silumin layer on the 1H18N9T steel have lamellar and on the SW18 steel – faced form.

  6. High-strength shape memory steels alloyed with nitrogen

    International Nuclear Information System (INIS)

    Ullakko, K.; Jakovenko, P.T.; Gavriljuk, V.G.

    1996-01-01

    Since shape memory effect in Fe-Mn-Si systems was observed, increasing attention has been paid to iron based shape memory alloys due to their great technological potential. Properties of Fe-Mn-Si shape memory alloys have been improved by alloying with Cr, Ni, Co and C. A significant improvement on shape memory, mechanical and corrosion properties is attained by introducing nitrogen in Fe-Mn-Si based systems. By increasing the nitrogen content, strength of the matrix increases and the stacking fault energy decreases, which promote the formation of stress induced martensite and decrease permanent slip. The present authors have shown that nitrogen alloyed shape memory steels exhibit recoverable strains of 2.5--4.2% and recovery stresses of 330 MPa. In some cases, stresses over 700 MPa were attained at room temperature after cooling a constrained sample. Yield strengths of these steels can be as high as 1,100 MPa and tensile strengths over 1,500 MPa with elongations of 30%. In the present study, effect of nitrogen alloying on shape memory and mechanical properties of Fe-Mn-Si, Fe-Mn-Si-Cr-Ni and Fe-Mn-Cr-Ni-V alloys is studied. Nitrogen alloying is shown to exhibit a beneficial effect on shape memory properties and strength of these steels

  7. Boric acid corrosion of low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.; White, G.; Collin, J.; Marks, C. [Dominion Engineering, Inc., Reston, Virginia (United States); Reid, R.; Crooker, P. [Electric Power Research Inst., Palo Alto, California (United States)

    2010-07-01

    In the last decade, the industry has been aware of a potential loss of coolant accident (LOCA) per the following scenario: primary water stress corrosion cracking (PWSCC) of a primary system component or weld leads to a coolant leak, the coolant corrodes a low alloy steel structural component (e.g., the reactor vessel (RV) or the reactor vessel head (RVH)), and corrosion degrades the pressure boundary leading to a loss of coolant accident. The industry has taken several steps to address this concern, including replacement of the most susceptible components (RVH replacement), enhanced inspection (both NDE of components and visual inspections for boric acid deposits), and safety analyses to determine appropriate inspection intervals. Although these measures are generally thought to have adequately addressed this issue, there have been some uncertainties in the safety analyses which the industry has sought to address in order to quantify the extent of conservatism in the safety analyses. Specifically, there has been some uncertainty regarding the rate of boric acid corrosion under various conditions which might arise due to a PWSCC leak and the extent to which boric acid deposits are retained near the leak under various geometries. This paper reviews the results of the Electric Power Research Institute (EPRI) Materials Reliability Program (MRP) boric acid corrosion (BAC) test programs conducted over the last 8 years, focusing on the most recent results of full-scale mockup testing of CRDM nozzle and bottom mounted nozzle (BMN) configurations. The main purpose of this presentation is to provide an overview of the latest understanding of the risk of boric acid corrosion as it is informed by the results of the testing conducted over the last eight years. The rate of boric acid corrosion has been found to be a function of many factors, including initial chemistry, the extent of concentration due to boiling, the temperature at which concentration takes place, the velocity

  8. Influence of alloying elements on the marine corrosion of low alloy steels

    International Nuclear Information System (INIS)

    Dajoux, E.; Malard, S.; Lefevre, Y.; Kervadec, D.; Gil, O.

    2005-01-01

    The study of steel marine corrosion leads to the survey of the parameters having an influence on this phenomenon. These parameters may be dependent on the seawater environment or on steel characteristics. Thus it appears that an experimental procedure could be set up in order to simulate immersion conditions in natural seawater. The system allows fifteen different steels with compositions ranging from carbon steels to stainless steels to be tested during some 14 months in natural seawater with or without microbiological activity. Electrochemical and gravimetric measurements are performed on immersed steel samples. Microbiological analyses are carried out either on the metallic surface and on the liquid medium. Possible influences of alloying elements and bacteria are studied. After a two-month immersion, first results show an influence of the chromium content on the steel corrosion resistance and on marine bacteria behaviour. They also reveal that the bio-film formed onto the carbon steel and low alloy steels surfaces tends to slow down the generalized corrosion or to increase localized corrosion depending on the steel alloying elements content. (authors)

  9. Fatigue and fracture behavior of low alloy ferritic forged steels

    International Nuclear Information System (INIS)

    Chaudhry, V.; Sharma, A.K.; Muktibodh, U.C.; Borwankar, Neeraj; Singh, D.K.; Srinivasan, K.N.; Kulkarni, R.G.

    2016-01-01

    Low alloy ferritic steels are widely used in nuclear industry for the construction of pressure vessels. Pressure vessel forged low alloy steels 20MnMoNi55 (modified) have been developed indigenously. Experiments have been carried out to study the Low Cycle Fatigue (LCF) and fracture behavior of these forged steels. Fully reversed strain controlled LCF testing at room temperature and at 350 °C has been carried out at a constant strain rate, and for different axial strain amplitude levels. LCF material behavior has been studied from cyclic stress-strain responses and the strain-life relationships. Fracture behavior of the steel has been studied based on tests carried out for crack growth rate and fracture toughness (J-R curve). Further, responses of fatigue crack growth rate tests have been compared with the rate evaluated from fatigue precracking carried out for fracture toughness (J-R) tests. Fractography of the samples have been carried out to reveal dominant damage mechanisms in crack propagation and fracture. The fatigue and fracture properties of indigenously developed low alloy steel 20MnMoNi55 (modified) steels are comparable with similar class of steels. (author)

  10. Development of Alloy Coating Process of Steel Pipe for Seawater service

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jong Man; Kwon, Taeg Kyu; Lee, Sang Hyeog [Daewoo Shipbuilding and Marine Engineering Co., Ltd., Okpo (Korea)

    2001-02-01

    The new alloy coating process was developed to apply steel pipe for seawater service. This process consists of Zn-Al hot-dip coating treatment immediately following after normal galvanizing treatment. The alloy coating process formed double layer after surface treatment, and the surface layer was similar to that of Galfan steel and the intermetallic layer was also similar to that of aluminized steel. The alloy coating layer protect steel pipe galvanically and provide steel pipe with high resistance to general corrosion of seawater. This new alloy coated steel pipe had also good weldability and adhesion strength of paints compared to galvanized steel. 5 refs., 14 figs.

  11. Irradiation effects in low-alloy reactor pressure vessel steels (Heavy-Section Steel Technology program series 4 and 5)

    International Nuclear Information System (INIS)

    McGowan, J.J.; Nanstad, R.K.; Thoms, K.R.; Menke, B.H.

    1985-01-01

    This report presents studies on the irradiation effects in low-alloy reactor pressure vessel steels. The Fourth Heavy-Section Steel Technology (HSST) Irradiation Series, almost completed, was aimed at elastic-plastic and fully plastic fracture toughness of low-copper weldments (''current practice welds''). A typical nuclear pressure vessel plate steel was included for statistical purposes. The Fifth HSST Irradiation Series, now in progress, is aimed at determining the shape of the K/sub IR/ curve after significant radiation-induced shift of the transition temperatures. This series includes irradiated test specimens of thicknesses up to 100 mm and weldment compositions typical of early nuclear power reactor pressure vessel welds. 27 refs., 22 figs

  12. Plane strain forging of a niobium micro-alloyed steel

    International Nuclear Information System (INIS)

    Balancin, O.; Ferran L, G.; Rio de Janeiro Univ.

    1984-01-01

    Various termomechanical treatments were carried out on a niobium micro-alloyed steel and a low carbon steel as reference material, using an apparatus for hot phane strain forging. Control of processing variables and the presence of niobium strongly modify the austenite microstructure, which upon decomposition produces various phases such as polygonal and acicular ferrite and martensite, alone or together in variable proportions. Corresponding to this diversity of structures there is a wide variation in mechanical properties at room temperature: the initial yield point varies from 310 to 650 MPa and the reduction of area in uniaxial tension from 82 to 57% for the niobium steel. These results show that hot forging a niobium micro-alloyed steel may be a suitable manufacturing process for satisfying a wide range of specifications in a final product with low equivalent carbon. (Author) [pt

  13. Chromium surface alloying of structural steels during laser treatment

    International Nuclear Information System (INIS)

    Kurov, I.E.; Nagornykh, S.N.; Sivukhin, G.A.; Solenov, S.V.

    1987-01-01

    Results of matrix alloying from the surface layer and creation of considerably increased chromium concentration in the depth which permits to increase the efficiency of laser treatment of steels (12Kh18N10T and 38KhN3M) in the process of their further mechanical polishing, are presented. The treatment was realized by continuous CO 2 -laser at different power densities and scanning rates are presented. A model describing the creation of anomalous distributions of the alloying element in steels is plotted

  14. Laves intermetallics in stainless steel-zirconium alloys

    International Nuclear Information System (INIS)

    Abraham, D.P.; McDeavitt, S.M.; Richardson, J.W. Jr.

    1997-01-01

    Laves intermetallics have a significant effect on properties of metal waste forms being developed at Argonne National Laboratory. These waste forms are stainless steel-zirconium alloys that will contain radioactive metal isotopes isolated from spent nuclear fuel by electrometallurgical treatment. The baseline waste form composition for stainless steel-clad fuels is stainless steel-15 wt.% zirconium (SS-15Zr). This article presents results of neutron diffraction measurements, heat-treatment studies and mechanical testing on SS-15Zr alloys. The Laves intermetallics in these alloys, labeled Zr(Fe,Cr,Ni) 2+x , have both C36 and C15 crystal structures. A fraction of these intermetallics transform into (Fe,Cr,Ni) 23 Zr 6 during high-temperature annealing; the authors have proposed a mechanism for this transformation. The SS-15Zr alloys show virtually no elongation in uniaxial tension, but exhibit good strength and ductility in compression tests. This article also presents neutron diffraction and microstructural data for a stainless steel-42 wt.% zirconium (SS-42Zr) alloy

  15. Local corrosion of high alloy steels under biodeposits

    International Nuclear Information System (INIS)

    Korovyakova, M.D.; Nikitin, V.M.; Speshneva, N.V.

    1999-01-01

    Impact of the bacteriozenosis different structural-functional state under biodeposits on corrosion resistance of the 12Kh18N10T and Kh18N10T high-alloy steels in the natural seawater is studied. It is shown that saturation of natural micro communities by separate aerobic and facultative-anaerobic bacterial monocultures increases corrosion resistance of these steels by their overgrow with biodeposits [ru

  16. Alloy-steel bolting materials for special applications

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    This specification covers regular and special-quality alloy steel bolting materials which may be used for nuclear and other special applications. Bolting materials as used in the specification cover rolled or forged bars, rotary pierced or extruded seamless tubes, bored bars, or forged hollows from forged or rolled bar segments to be machined into bolts, studs, washers, and nuts. Several grades of steel are covered and supplementary requirements of an optional nature are provided for use when special quality is desired

  17. CASTI handbook of stainless steels and nickel alloys. 2. ed.

    International Nuclear Information System (INIS)

    Lamb, S.

    2002-01-01

    This is the only up-to-date (2002) reference book that covers both stainless steels and nickel alloys. Written by 30 authors and peer reviewers with over 700 years of combined industrial experience, this CASTI handbook provides the latest stainless steels and nickel alloys information in a practical and comprehensive manner. For the project engineer, maintenance engineer or inspector, this book provides solutions to many of the corrosion problems encountered in aggressive environmental conditions. Some of the corrosive conditions covered are: stress corrosion cracking, reducing environments, halogenation, highly oxidizing environments, and high temperatures. Hundreds of different material applications and selections, throughout many industries, are referenced. It is an ideal reference source to assist in preventing or minimizing corrosion related problems, including those encountered during welding fabrication. This practical handbook also contains a handy 'Alloy Index' which lists each alloy by its ASTM Specification, UNS Number, common name, trade name and page number references. The second edition includes additional coverage of corrosion resistant alloys for downhole production tubing. The new material covers corrosion processes, corrosion rates, hydrogen sulfide environments, corrosion inhibitors, corrosion resistant alloys, the application of stainless steel in production conditions, and more

  18. On the rational alloying of structural chromium-nickel steels

    International Nuclear Information System (INIS)

    Astaf'ev, A.A.

    1982-01-01

    A study was made on the influence of chromium nickel, phosphorus on the critical brittleness temperature of Cr-Ni-Mo-V structural steels. It is shown that the critical brittleness temperature of these steels increases at chromium content more over than 2% and nickel content more than 2% in the result of carbide transformations during tempering. Increase of nickel content in Cr-Ni-Mo-V-steels strengthens the tendency to embrittlement during slow cooling, from tempering temperature owing to development of process of phosphorus grain-boundary segregation. Two mentioned mechanisms of embrittlement determine principles of rational steel alloying. The extreme dependence of the critical brittleness temperature on chromium and nickel content, which enables to choose the optimum composition of Cr-Ni-Mo-V-steels, was established

  19. 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...

  20. Corrosion properties of plasma deposited high-alloy steel

    Czech Academy of Sciences Publication Activity Database

    Voleník, Karel; Pražák, M.; Kalabisová, E.; Kreislová, K.; Neufuss, Karel

    2002-01-01

    Roč. 47, - (2002), s. 243-254 ISSN 0001-7043 R&D Projects: GA ČR GA106/99/0298 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma deposits, high-alloy steel, polarization curves, corrosion test Subject RIV: BL - Plasma and Gas Discharge Physics

  1. Carburizing treatment of low alloy steels: Effect of technological parameters

    Science.gov (United States)

    Benarioua, Younes

    2018-05-01

    The surface areas of the parts subjected to mechanical loads influence to a great extent the resistance to wear and fatigue. In majority of cases, producing of a hard superficial layer on a tough substrate is conducive to an increased resistance to mechanical wear and fatigue. Cementation treatment of low alloy steels which bonds superficial martensitic layer of high hardness and lateral compressive to a core of lower hardness and greater toughness is an example of a good solution of the problem. The high hardness of the martensitic layer is due to an increased concentration of interstitial carbon atoms in the austenite before quenching. The lower hardness of the core after quenching is due to the presence of ferrite and pearlite components which appear if the cooling rate after austenitization becomes lower than the critical on. The objective of the present study was to obtain a cemented surface layer on low alloy steel by means of pack carburizing treatment. Different steel grades, austenitization temperatures as well as different soaking times were used as parameters of the pack carburizing treatment. During this treatment, carbon atoms from the pack powder diffuse toward the steels surface and form compounds of iron carbides. The effect of carburizing parameters on the transformation rate of low carbon surface layer of the low alloy steel to the cemented one was investigated by several analytical techniques.

  2. Thermal Plasma Spheroidization of High-Nitrogen Stainless Steel Powder Alloys Synthesized by Mechanical Alloying

    Science.gov (United States)

    Razumov, Nikolay G.; Popovich, Anatoly A.; Wang, QingSheng

    2018-03-01

    This paper presents the results of experimental studies on the treatment of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, synthesized by the mechanical alloying (MA) of elemental powders in the flow of a thermal plasma. Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys were prepared by MA in the attritor under an argon atmosphere. For spheroidization of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, the TekSphero 15 plant manufactured by Tekna Plasma Systems Inc was used. The studies have shown the possibility of obtaining Fe-23Cr-11Mn-1N high-nitrogen spherical powders steel alloys from the powder obtained by MA. According to the results of a series of experiments, it was found that the results of plasma spheroidization of powders essentially depend on the size of the fraction due to some difference in the particle shape and flowability, and on the gas regime of the plasma torch. It is established that during the plasma spheroidization process, some of the nitrogen leaves the alloy. The loss rate of nitrogen depends on the size of the initial particles.

  3. Principles of alloy design in high nitrogen 12% chromium steels

    International Nuclear Information System (INIS)

    Goecmen, A.; Ernst, P.; Holmes, P.

    1999-01-01

    12% chromium steels are hardened by a martensitic transformation and by precipitation reactions of the martensite during a subsequent tempering treatment. The original alloy design of these steels is based on the intensifying effect of C on the martensitic transformation hardening as well as on the effects of V and Mo on intensity and stability of carbide precipitation hardening reactions. Advanced alloy design of high carbon 12% chromium steels makes use of f.c.c.-MX type carbonitrides to improve grain refinement and tempering resistance, whereas alloying with about 0.05 wt.-% nitrogen already plays a decisive role. In this paper, new alloy design opportunities provided by high nitrogen are reviewed, which promise to achieve a best possible compromise between grain size limitation, particle hardening and particle stability of 12% chromium steels. The crucial effects of the solubility product of MX-type phases on grain coarsening resistance, precipitation hardening and particle stability are reviewed. The advantages of high nitrogen steels to improve these properties are rationalized to result from the lower solubility of nitrides compared with carbides. As an advantageous opportunity of the achievable higher grain coarsening resistance, the normalizing temperature in high nitrogen steels can be increased in order to increase the amount of the less soluble and thereby slow coarsening f.c.c.-nitrides. In addition, as a consequence of a higher normalizing temperature, the solubility gap of nitrides in the austenite is expanded, which in turn enables an effective precipitation hardening due to low soluble nitrides in the metastable austenite before the martensitic transformation

  4. Neutron irradiation creep in stainless steel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Schuele, Wolfgang (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy)); Hausen, Hermann (Commission of the European Union, Institute for Advanced Materials, I-21020 Ispra (Vatican City State, Holy See) (Italy))

    1994-09-01

    Irradiation creep elongations were measured in the HFR at Petten on AMCR steels, on 316 CE-reference steels, and on US-316 and US-PCA steels varying the irradiation temperature between 300 C and 500 C and the stress between 25 and 300 MPa. At the beginning of an irradiation a type of primary'' creep stage is observed for doses up to 3-5 dpa after which dose the secondary'' creep stage begins. The primary'' creep strain decreases in cold-worked steel materials with decreasing stress and decreasing irradiation temperature achieving also negative creep strains depending also on the pre-treatment of the materials. These primary'' creep strains are mainly attributed to volume changes due to the formation of radiation-induced phases, e.g. to the formation of [alpha]-ferrite below about 400 C and of carbides below about 700 C, and not to irradiation creep. The secondary'' creep stage is found for doses larger than 3 to 5 dpa and is attributed mainly to irradiation creep. The irradiation creep rate is almost independent of the irradiation temperature (Q[sub irr]=0.132 eV) and linearly dependent on the stress. The total creep elongations normalized to about 8 dpa are equal for almost every type of steel irradiated in the HFR at Petten or in ORR or in EBR II. The negative creep elongations are more pronounced in PCA- and in AMCR-steels and for this reason the total creep elongation is slightly smaller at 8 dpa for these two steels than for the other steels. ((orig.))

  5. The Structure of the Silumin Coat on Alloy Cast Steels

    Directory of Open Access Journals (Sweden)

    T. Szymczak

    2012-04-01

    Full Text Available The work presents the analysis results of the structure of the coat obtained by dipping in silumin AlSi5 of two grades of alloy cast steel: GX6CrNiTi18-10 (LH18N9T and GX39Cr13 (LH14. The temperature of the silumin bath was 750±5°C, and the hold-up time of the cast steel element τ = 180 s. The absolute thickness of the coat obtained in the given conditions was g = 104 μm on cast steel GX6CrNiTi18-10 and g = 132 μm on GX39Cr13. The obtained coat consisted of three layers of different phase structure. The first layer from the base “g1`” was constructed of the phase AlFe including Si and alloy additives of the tested cast steel grades: Cr and Ni (GX6CrNiTi18-10 and Cr (GX39Cr13. The second layer “g1``” of intermetallic phases AlFe which also contains Si and Cr crystallizes on it. The last, external layer “g2” of the coat consists of the silumin containing the intermetallic phases AlFeSi which additionally can contain alloy additives of the cast steel. It was shown that there were no carbides on the coat of the tested cast steels which are the component of their microstructure, as it took place in the case of the coat on the high speed steels.

  6. Liquid Phase Sintering of Highly Alloyed Stainless Steel

    DEFF Research Database (Denmark)

    Mathiesen, Troels

    1996-01-01

    Liquid phase sintering of stainless steel is usually applied to improve corrosion resistance by obtaining a material without an open pore system. The dense structure normally also give a higher strength when compared to conventional sintered steel. Liquid phase sintrering based on addition...... of boride to AISI 316L type steels have previously been studied, but were found to be sensitive to intergranular corrosion due to formation of intermetallic phases rich in chromium and molybdenum. In order to improve this system further, new investigations have focused on the use of higher alloyed stainless...... steel as base material. The stainless base powders were added different amounts and types of boride and sintered in hydrogen at different temperatures and times in a laboratory furnace. During sintering the outlet gas was analyzed and subsequently related to the obtained microstructure. Thermodynamic...

  7. Transition welds in welding of two-ply steels

    International Nuclear Information System (INIS)

    Fartushnyj, V.G.; Evsyukov, Yu.G.

    1977-01-01

    Studied were physico-mechanical properties of welds made by various welding wires of chromium-nickel and nickel-chromium steels in submerged arc welding of double-layer steels with main layer of the VSt.3sp. carbon steel. It is shown that service-reliable structures welded of two-layer steels are obtained by providing the content from 11 to 20 % Ni in the automatically welded transition layer

  8. Oxidation behavior of steels and Alloy 800 in supercritical water

    International Nuclear Information System (INIS)

    Olmedo, A.M.; Bordoni, R.; Dominguez, G.; Alvarez, M.G.

    2011-01-01

    The oxidation behavior of a ferritic-martensitic steel T91 and a martensitic steel AISI 403 up to 750 h, and of AISI 316L and Alloy 800 up to 336 h in deaerated supercritical water, 450ºC-25 MPa, was investigated in this paper. After exposure up to 750 h, the weight gain data, for steels T91 and AISI 403, was fitted by ∆W=k t n , were n are similar for both steels and k is a little higher for T91. The oxide films grown in the steels were characterized using gravimetry, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction. The films were adherent and exhibited a low porosity. For this low oxygen content supercritical water exposure, the oxide scale exhibited a typical duplex structure, in which the scale is composed of an outer iron oxide layer of magnetite (Fe 3 O 4 ) and an inner iron/chromium oxide layer of a non-stoichiometric iron chromite (Fe,Cr) 3 O 4 . Preliminary results, with AISI 316L and Alloy 800, for two exposure periods (168 and 336 h), are also reported. The morphology shown for the oxide films grown on both materials up to 336 h of oxidation in supercritical water, resembles that of a duplex layer film like that shown by stainless steels and Alloy 800 oxide films grown in a in a high temperature and pressure (220-350ºC) of a primary or secondary coolant of a plant. (author) [es

  9. Intergranular brittle fracture of a low alloy steel. Global and local approaches

    International Nuclear Information System (INIS)

    Kantidis, E.

    1993-08-01

    The intergranular brittle fracture of a low alloy steel (A533B.Cl1) is studied: an embrittlement heat treatment is used to develop two brittle 'states' that fail through an intergranular way at low temperatures. This mode of fracture leads to an important shift of the transition temperature (∼ 165 deg C) and a decrease in the fracture toughness. The local approach to fracture, developed for cleavage, is applied to the case of intergranular fracture. Modifications are proposed. The physical supports of these models are verified by biaxial (tension-torsion) tests. From the local approaches developed for intergranular fracture, the static and dynamic fracture toughness of the embrittled steel is predicted. The local approach applied to a structural steel, which presents mixed modes of fracture (cleavage and intergranular), showed that this mode of fracture seems to be controlled by intergranular loss of cohesion

  10. Neutron irradiation effects on mechanical properties in SA508 Gr4N high strength low alloy steel

    International Nuclear Information System (INIS)

    Kim, Minchul; Lee, Kihyoung; Park, Sanggyu; Choi, Kwonjae; Lee, Bongsang

    2012-01-01

    The Reactor Pressure Vessel (RPV) is the key component in determining the lifetime of nuclear power plants because it is subject to the significant aging degradation by irradiation and thermal aging, and there is no practical method for replacing that component. Advanced reactors with much larger capacity than current reactor require the usage of higher strength materials inevitably. The SA508 Gr.4N Ni Cr Mo low alloy steel, in which Ni and Cr contents are larger than in conventional RPV steels, could be a promising RPV material offering improved strength and toughness from its tempered martensitic microstructure. For a structural integrity of RPV, the effect of neutron irradiation on the material property is one of the key issues. The RPV materials suffer from the significant degradation of transition properties by the irradiation embrittlement when its strength is increased by a hardening mechanism. Therefore, the potential for application of SA508 Gr.4N steel as the structural components for nuclear power reactors depends on its ability to maintain adequate transition properties against the operating neutron does. However, it is not easy to fine the data on the irradiation effect on the mechanical properties of SA508 Gr.4N steel. In this study, the irradiation embrittlement of SA508 Gr.4N Ni Cr Mo low alloy steel was evaluated by using specimens irradiated in research reactor. For comparison, the variations of mechanical properties by neutron irradiation for commercial SA508 Gr.3 Mn Mo Ni low alloy steel were also evaluated

  11. Mechanical properties of low alloy high phosphorus weathering steel

    Directory of Open Access Journals (Sweden)

    Jena B.K.

    2015-01-01

    Full Text Available Mechanical behaviour of two low alloy steels (G11 and G12 was studied with respect to different phosphorus contents. Tensile strength and yield strength increased while percentage elongation at fracture decreased on increasing phosphorus content. The SEM and light optical photomicrograph of low phosphorus steel (G11 revealed ferrite and pearlite microstructure. On increasing phosphorus content from 0.25 wt.% to 0.42 wt.%, the morphology of grain changed from equiaxed shape to pan-cake shape and grain size also increased. The Charpy V notch (CVN impact energy of G11 and G12 steel at room temperature was 32 J and 4 J respectively and their fractographs revealed brittle rupture with cleavage facets for both the steels. However, the fractograph of G11 steel after tensile test exhibited ductile mode of fracture with conical equiaxed dimple while that of G12 steel containing 0.42 wt. % P exhibited transgranular cleavage fracture. Based on this study, G11 steel containing 0.25 wt. % P could be explored as a candidate material for weathering application purpose where the 20°C toughness requirement is 27 J as per CSN EN10025-2:2004 specification.

  12. OF PLAIN CARBON AND LOW ALLOY STEELS

    African Journals Online (AJOL)

    Two steels En 3 and En 39 were given a TiC-TiN. CVD coating in the carburized and uncarburized conditions. The continuity of the coatings and their adherance to the substrate were examined. The thickness of the deposited coatings were also measured, their adherence to the substrate and their thickness was off ected by ...

  13. Resistance Element Welding of Magnesium Alloy/austenitic Stainless Steel

    Science.gov (United States)

    Manladan, S. M.; Yusof, F.; Ramesh, S.; Zhang, Y.; Luo, Z.; Ling, Z.

    2017-09-01

    Multi-material design is increasingly applied in the automotive and aerospace industries to reduce weight, improve crash-worthiness, and reduce environmental pollution. In the present study, a novel variant of resistance spot welding technique, known as resistance element welding was used to join AZ31 Mg alloy to 316 L austenitic stainless steel. The microstructure and mechanical properties of the joints were evaluated. It was found that the nugget consisted of two zones, including a peripheral fusion zone on the stainless steel side and the main fusion zone. The tensile shear properties of the joints are superior to those obtained by traditional resistance spot welding.

  14. Current Status of Development of High Nickel Low Alloy Steels for Commercial Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Chul; Lee, B. S.; Park, S. G.; Lee, K. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-12-15

    SA508 Gr.3 Mn-Mo-Ni low alloy steels have been used for nuclear reactor pressure vessel steels up to now. Currently, the design goal of nuclear power plant is focusing at larger capacity and longer lifetime. Requirements of much bigger pressure vessels may cause critical problems in the manufacturing stage as well as for the welding stage. Application of higher strength steel may be required to overcome the technical problems. It is known that a higher strength and fracture toughness of low alloy steels such as SA508 Gr.4N low alloy steel could be achieved by increasing the Ni and Cr contents. Therefore, SA508 Gr.4N low alloy steel is very attractive as eligible RPV steel for the next generation PWR systems. In this report, we propose the possibility of SA508 Gr.4N low alloy steel for an application of next generation commercial RPV, based on the literature research result about development history of the RPV steels and SA508 specification. In addition, we have surveyed the research result of HSLA(High Strength Low Alloy steel), which has similar chemical compositions with SA508 Gr.4N, to understand the problems and the way of improvement of SA508 Gr.4N low alloy steel. And also, we have investigated eastern RPV steel(WWER-1000), which has higher Ni contents compared to western RPV steel.

  15. Testing and assessment of low alloy steel for marine application

    International Nuclear Information System (INIS)

    Amjad, M.; Ahmad, S.; Mahmood, K.; Qureshi, A.H.

    2007-01-01

    This paper is an account of the work carried out during the assessment of low alloy steel (WH-80) for marine application. The relevant acceptance criteria consulted during the process is DEFST AN 02-874 and a standard reference material. Assessment is based on the experimental results of the tests carried out for the steel. Testing comprised of mechanical (tensile, impact and hardness) tests, corrosion (immersion corrosion and stress corrosion cracking) tests, metallography test and weldability (weld joint strength, controlled thermal severity -CTS and Y -Groove) tests undertaken at various testing laboratories in Pakistan. The results obtained after testing have been compared with acceptance criteria (DEFSTAN 02-874 and standard reference material). Moreover results have been compared with contemporary steels used for marine applications. Results showed a reasonable agreement with results available in literature for other low alloy steels with respect to mechanical strength and weldability. Steel weldments qualified the weld joint strength tests and weldability tests. Toughness has been measured at various temperatures. Results revealed that the toughness of base metal is higher than heat affected zone (HAZ) and weld metal. In weldability tests, weld metal and HAZ were examined microscopically to investigate integrity of weld. No cracks have been observed in the weld which indicates complete diffusion in to the welding material. WH- 80 steel has exhibited comparatively high corrosion rate, reduction in tensile strength during SCC test and low Charpy energy values at -50 degree C. It is therefore concluded that the WH-80 steel is unsuitable for use in application at subzero (OC) temperatures and in highly corrosive environment. (author)

  16. Alloying effect on martensite transformation in stainless steels

    International Nuclear Information System (INIS)

    Gulyaev, A.P.; Shlyamnev, A.P.; Sorokina, N.A.

    1975-01-01

    The effect of cobalt, nickel, molybdenum on the martensite transformation kinetics in stainless steels containing 9 to 13% Cr has been studied. Cobalt in Fe-Cr base alloys decreases the temperature of the Msub(in) and Msub(fin) points without a considerable decrease of the martensite phase amount after the transformation. Nickel reduces the martensite transformation temperature range, the nickel effect being enhanced in the presence of cobalt, which is characterized by a change of the linear dependence Msub(in)=f(%Ni) for a quadratic one. Molybdenum decreases the temperature of the Msub(in) and Msub(fin) points intensively, thus, substantially increasing the residual austenite amount. In the steels investigated Ni and Co decrease, whereas Mo increases, to some extent, the temperature of the reverse a-γ-transformation. The reduction of chromium content from 13 to 9% stimulates the martensite transformation initiation, that is why, in alloys containing 9% Cr, the increase in the contents of Ni, Co., Mo with the martensite structure maintained is possible. A further alloying of steel containing 13% Cr with these elements is rather limited due to the inhibition of the martensite transformation

  17. Corrosion of low alloy steels in natural seawater. Influence of alloying elements and bacteria

    International Nuclear Information System (INIS)

    Dajoux Malard, Emilie

    2006-01-01

    Metallic infrastructures immersed in natural seawater are exposed to important corrosion phenomena, sometimes characterised as microbiologically influenced corrosion. The presence of alloying elements in low alloy steels could present a corrosion resistance improvement of the structures. In this context, tests are performed with commercial steel grades, from 0,05 wt pc Cr to 11,5 wt pc Cr. They consist in 'on site' immersion in natural seawater on the one hand, and in laboratory tests with immersion in media enriched with marine sulphide-producing bacteria on the other hand. Gravimetric, microbiological, electrochemical measurements and corrosion product analyses are carried out and show that corrosion phenomenon is composed of several stages. A preliminary step is the reduction of the corrosion kinetics and is correlated with the presence of sessile sulphide-producing bacteria and an important formation of sulphur-containing species. This phase is shorter when the alloying element content of the steel increases. This phase is probably followed by an increase of corrosion, appearing clearly after an 8-month immersion in natural seawater for some of the grade steels. Chromium and molybdenum show at the same time a beneficial influence to generalised corrosion resistance and a toxic effect on sulphide-producing bacteria. This multidisciplinary study reflects the complexity of the interactions between bacteria and steels; sulphide-producing bacteria seem to be involved in corrosion processes in natural seawater and complementary studies would have to clarify occurring mechanisms. (author) [fr

  18. Intergranular stress corrosion cracking of low alloy and carbon steels in high temperature pure water

    International Nuclear Information System (INIS)

    Tsubota, M.; Sakamoto, H.; Tsuzuki, R.

    1993-01-01

    Stress corrosion cracking (SCC) behavior of low alloy steels (A508 and SNCM630) and a carbon steel (SGV480) in high temperature water has been examined with relation to the heat treatment condition, including a long time aging, and the mechanical properties. Intergranular stress corrosion cracking (IGSCC) as observed in the highly hardened specimens, and there was observed in the highly hardened specimens, and there was observed in the highly hardened specimens, and there was observed a close relationship between hardness and SCC susceptibility. From the engineering point of view, it was concluded that adequate SR (stress relief) or tempering heat treatment is necessary to avoid the IGSCC of the welded structures made of low alloy and carbon steels. A508 heat treated with specified quench and temper did not show the SCC susceptibility, even after aging 10000 hours at 350, 400 and 450 degrees C. Tensile properties corresponding to the critical hardness for SSC susceptibility coincided with the values at the 'necking point' in the true stress-strain curve. Ductile-brittle transition observed in the fracture toughness test also occurred at around the critical hardness for SCC susceptibility. Therefore, it was conjectured that the limitation of plasticity was an absolute cause for the SCC susceptibility of the steels

  19. Regularities of transition of steel corrosion products into aqueous medium

    International Nuclear Information System (INIS)

    Nikitin, V.I.; Gvozd', A.M.; Karpova, T.Ya.

    1981-01-01

    Effect of different factors on a degree of steel corrosion product transition to a water medium has been studied. Ratio of a specific masm qsub(c) of the corrosion products transferring to the water and a specific masm q of all the steel corrosion products produced under the given conditions was used as a criterium characterizing a degree of corrosion product transition from steel surfaces to water. The transition degree to water at a high temperature of different kind steel corrosion products differs relatively few (qsub(c)/q=0.5-0.7) in the water containing oxygen and different salts on increasing temperature, the corrosion process is characterized with continuous decrease of a relative amount of the corrosion products transferring to the medium. On the contrary, in the deaerated water the transition degree of perlite steel corrosion products to water remains constant in a wide temperature range (100-320 deg C). Besides chromium, nickel being a part of austenitic steel composition affects positively decrease of the transition degree of the corrosion products to water as well as q and qsub(c) reduction. The most difference in corrosion characteristics and the transition degree to water is observed when affecting colant steels in the low-temperature zone of the steam generator [ru

  20. Development of Zn50 Brazing Alloy for Joining Mild Steel to Mild Steel (SAE1018

    Directory of Open Access Journals (Sweden)

    S.C. Nwigbo

    2014-09-01

    Full Text Available This work has developed new brazing alloys for joining mild steel to mild steel (SAE1018 at a lower temperature. The alloys blends and error analysis were done by experimental design software (Design Expert 8.0.7.1. Design of experiments was done by Scheffe quadratic mixture method. The liquidus temperatures were predicted by calculation of phase diagrams of the alloying metals. The brazing alloys were produced by gravity technique and melted using silicon carbide graphite crucible. The quality of the brazing alloys was analyzed by optical microscopy (OM, atomic absorption spectroscopy (AAS and fourier transform infrared spectroscopy (FT-IR. Brazed joints were produced by torch method with a commercial flux. Brazing temperatures (liquidus were tracked by a digital infrared/laser pyrometer. Some mechanical properties studied were tensile strength and hardness. Finally, brazed joints produced from the developed brazing alloys were compared to that produced from muntz brass. Six (6 brazing alloys were successfully developed. Zinc and manganese were the main components, to which were added; 3 to 4 %wt silver and 11 to15 %wt modifying element. The microstructure showed a typical eutectic structure with zinc-rich phase distributed uniformly in the matrix with a combination of different sizes of dendrite, rounded blocks of compounds and hypoeutectic structures. AAS results indicated minimal out-gassing of zinc and FT-IR results indicated very low presence of atmospheric gas. The range of brazing temperature for best results was recorded from 690.90 to 735.10 0C. The joints produced from the developed brazing alloys had acceptable strengths with improved stress-strain behaviour compared to muntz brass.

  1. On rolling of alloyed steels on the continuous light-section mill 250

    International Nuclear Information System (INIS)

    Grigor'ev, V.K.; Antipov, V.F.; Zamotin, V.M.; Kuznetsov, Yu.M.

    1976-01-01

    Using the method of computed ratios, the expected loads (torques) have been calculated in the rolling of alloyed steels on the light-section mill 250 of the Chelyabinsk metallurgical works. The deviation of the computed torques from those measured for steels 35GS and St5ps does not exceed -6%. Data are given on changes in torques during the rolling of alloyed steels in the different stands as compared with the actual data for the rolling of ordinary steel. Calculations show, and experimental data confirm, that, according to the torque value, it is possible to roll alloyed steels of sufficiently wide assortment on mill 250

  2. Surface Nb-ALLOYING on 0.4C-13Cr Stainless Steel: Microstructure and Tribological Behavior

    Science.gov (United States)

    Yu, Shengwang; You, Kai; Liu, Xiaozhen; Zhang, Yihui; Wang, Zhenxia; Liu, Xiaoping

    2016-02-01

    0.4C-13Cr stainless steel was alloyed with niobium using double glow plasma surface alloying and tribological properties of Nb-alloyed steel such as hardness, friction and wear were measured. Effects of the alloying temperature on microstructure and the tribological behavior of the alloyed steel were investigated compared with untreated steel. Formation mechanisms of Nb-alloyed layers and increased wear resistance were also studied. The result shows that after surface Nb-alloying treatment, the 0.4C-13Cr steel exhibits a diffusion adhesion at the alloyed layer/substrate interface and improved tribological property. The friction coefficient of Nb-alloyed steel is decreased by about 0.3-0.45 and the wear rate after Nb-alloying is only 2-5% of untreated steel.

  3. Austenitic stainless steel-to-ferritic steel transition joint welding for elevated temperature service

    International Nuclear Information System (INIS)

    King, J.F.; Goodwin, G.M.; Slaughter, G.M.

    1978-01-01

    Transition weld joints between ferritic steels and austenitic stainless steels are required for fossil-fired power plants and proposed nuclear plants. The experience with these dissimilar-metal transition joints has been generally satisfactory, but an increasing number of failures of these joints is occurring prematurely in service. These concerns with transition joint service history prompted a program to develop more reliable joints for application in proposed nuclear power plants

  4. Localized corrosion of high alloyed austenitic stainless steels

    International Nuclear Information System (INIS)

    Morach, R.; Schmuki, P.; Boehni, H.

    1992-01-01

    The susceptibility of several high alloyed stainless steels against localized corrosion was investigated by traditional potentiostatic and -kinetic methods and the current transient technique. Different test cells, proposed in literature, were evaluated for use in testing of plate materials. The AVESTA-cell showed to be not useful for potentiokinetic current density potential curves, but useable for pitting experiments. After pickling and prepassivation epoxy embedded materials proved to be resistant to crevice corrosion at the metal-resin interface. The electrode in form of a wire was the most reliable crevice free cell design. The grinding of the samples in the pretreatment procedure was found to have a large effect on the pitting corrosion behaviour. Using different paper types with varying grit, a drop in pitting potential for rougher surfaces and an increase in metastable pitting activity was found. Increasing surface roughness led also to changes in the electronic structure of the passive film reflected by a lower bandgap energy. High alloyed stainless steels showed no breakdown potential within the examined potential range. Compared to 18/8 type stainless steels significantly less transients were found. The number of transients decreases with increasing molybdenum and chromium content

  5. The effect of alloying and treatment on martensite transformation during deformation in Fe-Cr-Mn steels with unstable austenite

    International Nuclear Information System (INIS)

    Malinov, L.S.; Konop, V.I.; Sokolov, K.N.

    1977-01-01

    The effect is studied of alloying with chromium (6-10%), silicon (1-2%), molybdenum (1-3%), and copper (2%), the heat treatment conditions, and the deformation conditions, or the martensitic transformation and mechanical properties of Fe-Cr-Mn steels of the transitional class based on 0G8AM2S. It is shown that appropriate alloying and treatment, taking into account the degree of stability of the austenite, can ensure a complex of high mechanical properties of the steels investigated. For instance, the treatment of steel 0Kh10AG8MD2S by the technique: hardening+ 40% deformation at 400 deg C + 10% deformation at room temperature has yielded the following mechanical properties: sigmasub(B)=150 kgf/mm 2 , sigmasub(T)=110 kgf/mm 2 , sigma=18%, psi=32%

  6. Grain boundary phosphorus segregation under thermal aging in low alloy steels

    International Nuclear Information System (INIS)

    Nakata, Hayato; Fujii, Katsuhiko; Fukuya, Koji; Shibata, Masaaki; Kasada, Ryuta; Kimura, Akihiko

    2002-01-01

    Intergranular embrittlement due to grain boundary segregation of phosphorus is recognized as one of the potential degradation factors in irradiated reactor pressure vessel steels at high neutron fluences. In this study, investigations on low alloy steels thermally aged at 400-500degC were conducted to evaluate the correlation between phosphorus segregation and intergranular embrittlement. Phosphorus segregation determined using Auger electron spectroscopy increased after aging above 450degC and was in good agreement with the calculated value based on McLean model. No influence of thermal aging was observed in tensile properties. The ductile brittle transition temperature determined using 1/3 size charpy impact tests increased of 12degC after aging at 450degC for 3000 hours. These results indicated that there is a threshold level of phosphorus segregation for non-hardening embrittlement and that the level is around 0.14 for P/Fe peak ratio. (author)

  7. Grain boundary phosphorus segregation under thermal aging in low alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Hayato; Fujii, Katsuhiko; Fukuya, Koji [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan); Shibata, Masaaki; Kasada, Ryuta; Kimura, Akihiko [Kyoto Univ. (Japan)

    2002-09-01

    Intergranular embrittlement due to grain boundary segregation of phosphorus is recognized as one of the potential degradation factors in irradiated reactor pressure vessel steels at high neutron fluences. In this study, investigations on low alloy steels thermally aged at 400-500degC were conducted to evaluate the correlation between phosphorus segregation and intergranular embrittlement. Phosphorus segregation determined using Auger electron spectroscopy increased after aging above 450degC and was in good agreement with the calculated value based on McLean model. No influence of thermal aging was observed in tensile properties. The ductile brittle transition temperature determined using 1/3 size charpy impact tests increased of 12degC after aging at 450degC for 3000 hours. These results indicated that there is a threshold level of phosphorus segregation for non-hardening embrittlement and that the level is around 0.14 for P/Fe peak ratio. (author)

  8. Fabrication of spherical high-nitrogen stainless steel powder alloys by mechanical alloying and thermal plasma spheroidization

    Science.gov (United States)

    Razumov, Nikolay G.; Wang, Qing Sheng; Popovich, Anatoly A.; Shamshurin, Aleksey I.

    2018-04-01

    This paper describes the results of experimental studies on the treatment of Fe-23Cr-11Mn-1N high-nitrogen stainless steel powder alloys, synthesized by the mechanical alloying (MA) of elemental powders in the flow of a radio frequency thermal plasma. The as-milled powder with irregular particles were successfully converted into spherical high-nitrogen stainless steel powder alloy. Measurement of the residual nitrogen content in the obtained powder, shown that during the plasma spheroidization process, part of the nitrogen escapes from the alloy.

  9. 75 FR 69125 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China

    Science.gov (United States)

    2010-11-10

    ... with material injury by reason of imports from China of certain seamless carbon and alloy steel standard, line, and pressure pipe (``seamless SLP pipe''), provided for in subheadings 7304.19.10, 7304.19... Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China Determination On the basis of...

  10. Thermal creep properties of alloy D9 stainless steel and 316 stainless steel fuel clad tubes

    International Nuclear Information System (INIS)

    Latha, S.; Mathew, M.D.; Parameswaran, P.; Bhanu Sankara Rao, K.; Mannan, S.L.

    2008-01-01

    Uniaxial thermal creep rupture properties of 20% cold worked alloy D9 stainless steel (alloy D9 SS) fuel clad tubes for fast breeder reactors have been evaluated at 973 K in the stress range 125-250 MPa. The rupture lives were in the range 90-8100 h. The results are compared with the properties of 20% cold worked type 316 stainless steel (316 SS) clad tubes. Alloy D9 SS were found to have higher creep rupture strengths, lower creep rates and lower rupture ductility than 316 SS. The deformation and damage processes were related through Monkman Grant relationship and modified Monkman Grant relationship. The creep damage tolerance parameter indicates that creep fracture takes place by intergranular cavitation. Precipitation of titanium carbides in the matrix and chromium carbides on the grain boundaries, dislocation substructure and twins were observed in transmission electron microscopic investigations of alloy D9 SS. The improvement in strength is attributed to the precipitation of fine titanium carbides in the matrix which prevents the recovery and recrystallisation of the cold worked microstructure

  11. Dependence of magnetic permeability on residual stresses in alloyed steels

    Science.gov (United States)

    Hristoforou, E.; Ktena, A.; Vourna, P.; Argiris, K.

    2018-04-01

    A method for the monitoring of residual stress distribution in steels has been developed based on non-destructive surface magnetic permeability measurements. In order to investigate the potential utilization of the magnetic method in evaluating residual stresses, the magnetic calibration curves of various ferromagnetic alloyed steels' grade (AISI 4140, TRIP and Duplex) were examined. X-Ray diffraction technique was used for determining surface residual stress values. The overall measurement results have shown that the residual stress determined by the magnetic method was in good agreement with the diffraction results. Further experimental investigations are required to validate the preliminary results and to verify the presence of a unique normalized magnetic stress calibration curve.

  12. Galvanic corrosion study of aluminium alloy plates mounted to stainless and mild steel bolts by accelerated exposure test

    OpenAIRE

    MREMA, Emmanuel; ITOH, Yoshito; KANEKO, Akira; HIROHATA, Mikihito

    2016-01-01

    Despite the fact that aluminium alloy members have a proven durability over stainless steel members, their joint fasteners like bolts, nuts and washers are drawn from steel material due to aluminium alloy inferior mechanical properties. Bare contact between aluminium alloy members and stainless steel fasteners results to galvanic corrosion of aluminium alloy members. A corrosion behaviour study was carried out on different aluminium alloy types with different surface treatments mounted to sta...

  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. Properties of low-alloy steel with tellurium

    International Nuclear Information System (INIS)

    Popova, L.V.; Lebedev, D.V.; Litvinenko, D.A.; Nasibov, A.G.

    1983-01-01

    The results of investigations into 09G2 and 09G2F steels alloyed with tellurium after controlled rolling are presented. 0.002-0.011% tellurium additions did not change strength and plastic properties of the steels after controlled rolling. Tellurium additions results in 40-50% increase of the steel impact strength on samples With circular and sharp cuts in brittle-viscous region. 0.002-0.003% of tellurium is considered to be the optimum content from the view point of increa=. sing steel strength. Increase of impact strength takes place at the expense of growth of both work function of crack formation and work function of crack propagation but in different temperature ranges: at the expense of firstone at 80-40 deg C, at the expense of second one at 20-40 deg C. 0.002-0.011% teilurium additions mainly at the expense of sulphide globularization bring about decrease of anisotropy of steet properties by impact strength reducing anisotropy factor from 2 to 1.5

  15. Optimal control of conditions of deformation during rolling the bar alloy from alloy steel

    International Nuclear Information System (INIS)

    Inatovich, Yu.V.; Shilov, V.A.; Shvarts, D.L.; Kudelin, S.P.

    2001-01-01

    A complex of programs for determining the optimal gaps between rollers during rolling of simple merchant sections of alloy steels of a wide brand assortment (12KhN3A, Kh17N2, Kh18N10T) was elaborated. Experience in calculations made according to the programs suggests advisability of their use in the automated design systems for roller calibration and for adjustment of section mills [ru

  16. The design of an Fe-12Mn-O.2Ti alloy steel for low temperature use

    Science.gov (United States)

    Hwang, S. K.; Morris, J. W., Jr.

    1977-01-01

    An investigation was made to improve the low temperature mechanical properties of Fe-8 approximately 12% Mn-O 2Ti alloy steels. A two-phase(alpha + gamma) tempering in combination with cold working or hot working was identified as an effective treatment. A potential application as a Ni-free cryogenic steel was shown for this alloy. It was also shown that an Fe-8Mn steel could be grain-refined by a purely thermal treatment because of its dislocated martensitic structure and absence of epsilon phase. A significant reduction of the ductile-brittle transition temperature was obtained in this alloy. The nature and origin of brittle fracture in Fe-Mn alloys were also investigated. Two embrittling regions were found in a cooling curve of an Fe-12Mn-O 2Ti steel which was shown to be responsible for intergranular fracture. Auger electron spectroscopy identified no segregation during solution-annealing treatment. Avoiding the embrittling zones by controlled cooling led to a high cryogenic toughness in a solution-annealed condition.

  17. Influence of shock induced polymorphic transition on penetration in steel

    International Nuclear Information System (INIS)

    Hereil, P.L.; Fanget, A.

    1994-01-01

    The effects of polymorphic transition for the impact of a 27NCD10 steel projectile on a 27NCD10 steel target at 1280 m/s is presented. Comparisons between results of 2D numerical calculations performed with and without polymorphic transition show the influence of this phenomenon on stress distribution and tension zones in the target and in the projectile. Good agreement between experimental and calculated free surface velocity profiles is obtained with polymorphic transition and damage models taken into account. (orig.)

  18. Phase equilibria and thermodynamic properties of high-alloy tool steels : theoretical and experimental approach

    OpenAIRE

    Bratberg, Johan

    2005-01-01

    The recent development of tool steels and high-speed steels has led to a significant increase in alloy additions, such as Co, Cr, Mo, N, V, and W. Knowledge about the phase relations in these multicomponent alloys, that is, the relative stability between different carbides or the solubility of different elements in the carbides and in the matrix phase, is essential for understanding the behaviour of these alloys in heat treatments. This information is also the basis for improving the properti...

  19. The use of niobium bearing ferro-alloys in the manufacture of structural steels in the USSR

    International Nuclear Information System (INIS)

    Lyakishev, N.P.

    1984-01-01

    Information is presented concerning the use of niobium as a microalloying element in constructional steels of various types. Niobium causes substantial refinement of grain size and inhibits the process of static recrystallization. It is, therefore, widely used in high strength low-alloy steels subjected to controlled-rolling or thermo-mechanical treatment. The largest strength increases are observed with a niobium content of up to 0.05 percent at which point the impact toughness diminishes slightly. Increased amounts of niobium favorably affect both the impact toughness and the transition temperature. The effectiveness of niobium usage in existing types of construction steels, including HSLA steels intended for the manufacture of weldable large-diameter linepipe for use in Arctic environments is described

  20. Bainite formation kinetics in high carbon alloyed steel

    International Nuclear Information System (INIS)

    Luzginova, N.V.; Zhao, L.; Sietsma, J.

    2008-01-01

    In recent years, many investigations have been carried out on the modeling of the bainite formation. In the present work, a physical approach proposed in the literature is implemented to model the formation of lower bainite in high carbon steels (1 wt.% C). In this model, the carbon diffusion is assumed to control the kinetics of the bainite formation. Both the nucleation and the growth rates are considered in an Avrami type analysis. The effect of alloying elements is taken into account considering only the thermodynamics of the system. The results and the physical meaning of the model parameters are discussed. It is shown that the diffusional approach gives a reasonable description of bainite formation kinetics in high carbon steel. Only two fitting parameters are used: the first accounts for carbon grain-boundary diffusion and the second is the initial nucleation-site density. The model satisfactorily accounts for the effect of transformation temperature, but does not take into account the carbide precipitation during bainite formation and the effect of alloying elements on the diffusion coefficient of carbon

  1. Low cycle fatigue behaviors of low alloy steels in 310 .deg. C deoxygenated water

    International Nuclear Information System (INIS)

    Jang, Hun

    2008-02-01

    After low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310 .deg. C deoxygenated water, the fatigue surface and the sectioned area of specimens were observed to understand the effect of the cyclic strain rate on the environmentally assisted cracking behaviors. From the fatigue crack morphologies of the specimen tested at a strain rate of 0.008 %/s, unclear ductile striations and blunt crack tip were observed. So, metal dissolution could be the main cracking mechanism of the material at the strain rate. On the other hand, on the fatigue surface of the specimen tested at strain rates of 0.04 and 0.4 %/s, the brittle cracks and the flat facets, which are the evidence of the hydrogen induced cracking, were observed. Also, the tendency of linkage between the main crack and micro-cracks was observed on the sectioned area. Therefore, the main cracking mechanism at the strain rates of 0.04 and 0.4 %/s could be the hydrogen induced cracking. Additionally, the evidence of the dissolved MnS inclusions was observed on the fatigue surface from energy dispersive x-ray spectrometer analyses. So, despite of the low sulfur content of the test material, the sulfides seem to contribute to environmentally assisted cracking of SA508 Gr.1a low alloy steel in 310 .deg. C deoxygenated water. Additionally, our experimental fatigue life data of SA508 Gr.1a low alloy steel (heat A) showed a consistent difference with statistical model produced in argon national laboratory. So, additional low cycle fatigue tests of other heat SA508 Gr.1a (heat B) and SA508 Gr.3 low alloy steels were performed to investigate the effect of material variability on fatigue behaviors of low alloy steels in 310 .deg. C deoxygenated water. In results, the fatigue lives of three low alloy steels were increased following order: SA508 Gr.1a low alloy steel - heat A, SA508 Gr.3 low alloy steel, and SA508 Gr.1a low alloy steel - heat B. From microstructure observation, the fatigue surface of SA508 Gr.1a low alloy

  2. Stress transmission through Ti-Ni alloy, titanium and stainless steel in impact compression test.

    Science.gov (United States)

    Yoneyama, T; Doi, H; Kobayashi, E; Hamanaka, H; Tanabe, Y; Bonfield, W

    2000-06-01

    Impact stress transmission of Ti-Ni alloy was evaluated for biomedical stress shielding. Transformation temperatures of the alloy were investigated by means of DSC. An impact compression test was carried out with use of split-Hopkinson pressure-bar technique with cylindrical specimens of Ti-Ni alloy, titanium and stainless steel. As a result, the transmitted pulse through Ti-Ni alloy was considerably depressed as compared with those through titanium and stainless steel. The initial stress reduction was large through Ti-Ni alloy and titanium, but the stress reduction through Ti-Ni alloy was more continuous than titanium. The maximum value in the stress difference between incident and transmitted pulses through Ti-Ni alloy or titanium was higher than that through stainless steel, while the stress reduction in the maximum stress through Ti-Ni alloy was statistically larger than that through titanium or stainless steel. Ti-Ni alloy transmitted less impact stress than titanium or stainless steel, which suggested that the loading stress to adjacent tissues could be decreased with use of Ti-Ni alloy as a component material in an implant system. Copyright 2000 Kluwer Academic Publishers

  3. Controlling the ductile to brittle transition in Fe–9%Cr ODS steels

    Energy Technology Data Exchange (ETDEWEB)

    Di Martino, S.F., E-mail: s.f.di-martino@lboro.ac.uk; Riddle, N.B.; Faulkner, R.G.

    2013-11-15

    Probably the most important range of materials for consideration as the blanket material for the tokamak design for fusion reactors ITER and DEMO is the high alloy Fe–9Cr oxide dispersion strengthened ferritic steels. Ferritic steels possess exceptional thermal conductivity and low thermal expansion and are resistant to void swelling. Their main drawback is high ductile to brittle transition temperatures, particularly in the oxide dispersion strengthened versions. This paper describes attempts to reduce the DBTT in an un-irradiated ferritic steel by a novel heat treatment procedure. New batches of high alloy Fe–9Cr oxide dispersion strengthened (Eurofer) ferritic steel have been produced by a powder metallurgy route, and relatively homogeneous material has been produced by hot isostatic pressing (HIP). Mini-Charpy test specimens were made from materials which had been subjected to a matrix of heat treatments with varying solution treatment temperature (ST), cooling rate from the ST temperature, and tempering treatment. The initial DBTT was in the range of 150–200 °C (423–473 K). Downward shifts of up to approximately 200 °C (473 K) have been observed after solution treatment at 1300 °C (1573 K) followed by slow cooling. This paper describes the microstructure of this material, and discussion is made of the likely microstructural factors needed to produce these DBTT downward shifts.

  4. Irradiation damage behavior of low alloy steel wrought and weld materials

    International Nuclear Information System (INIS)

    Stofanak, R.J.; Poskie, T.J.; Li, Y.Y.; Wire, G.L.

    1993-01-01

    A study was undertaken to evaluate the irradiation damage response of several different types of low alloy steel: vintage type ASTM A302 Grade B (A302B) plates and welds containing different Ni and Cu concentrations, 3.5% Ni steels similar to ASTM A508 Class 4, welds containing about 1% Ni (similar to type 105S), and 3.5% Ni steels with ''superclean'' composition. All materials were irradiated at several different irradiation damage levels ranging from 0.0003 to 0.06 dpa at 232C (450F). Complete Charpy V-notch impact energy transition temperature curves were generated for all materials before and after irradiation to determine transition temperature at 4IJ (30 ft-lb) or 47J (35 ft-lb) and the upper shelf energy. Irradiation damage behavior was measured by shift in Charpy 41J or 47J transition temperature (ΔTT4 41J or ΔTT 47J ) and lowering of upper shelf Charpy energy at a given irradiation damage level. It was found that chemical composition greatly influenced irradiation damage behavior; highest irradiation damage (greatest ΔTT) was found in an A302B type weld containing 1.28% Ni and 0.20% Cu while the least damage was found in 3.5% Ni, 0.05% Cu, superclean wrought materials. Combination of Ni and Cu was found to affect irradiation damage behavior at higher irradiation damage levels in the A302B welds where the 1.28% Ni, 0.20% Cu weld showed more damage than a 0.60% Ni, 0.31% Cu weld. For the 3.5% Ni steels, fabrication influenced irradiation behavior in that a silicon (Si) killed material showed greater irradiation damage than a low silicon material. In general, the 3.5% Ni materials with low copper showed less irradiation damage than the A302B materials

  5. Comparison on Mechanical Properties of SA508 Gr.3 Cl.1, Cl.2, and Gr.4N Low Alloy Steels for Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Chul; Park, Sang-Gyu; Lee, Bong-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Ki-Hyoung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2014-10-15

    In this study, microstructure and mechanical properties of SA508 Gr.3 Cl. 1, Cl.2, and Gr.4N low alloy steels are characterized to compare their properties. To evaluate the fracture toughness in the transition region, the master curve method according to ASTM E1921 was adopted in the cleavage transition region. Tensile tests and Charpy impact tests were also performed to evaluate the mechanical properties, and a microstructural investigation was carried out. The microstructure and mechanical properties of SA508 Gr.3 Cl.1, Cl2 and Gr.4N low alloy steels were characterized.. The predominant microstructure of SA508 Gr.4N model alloy is tempered martensite, while SA508 Gr.3 Cl.1 and Cl.2 steels show a typical tempered upper bainitic structure. SA508 Gr. 4N model alloy shows the best strength and transition behavior among the three SA508 steels. SA508 Gr.3 Cl.2 steel also has quite good strength, but there is a loss of toughness.

  6. New technique for producing the alloys based on transition metals

    International Nuclear Information System (INIS)

    Dolukhanyan, S.K.; Aleksanyan, A.G.; Shekhtman, V.Sh.; Mantashyan, A.A.; Mayilyan, D.G.; Ter-Galstyan, O.P.

    2007-01-01

    In principle new technique was elaborated for obtaining the alloys of refractory metals by their hydrides compacting and following dehydrogenation. The elaborated technique is described. The conditions of alloys formation from different hydrides of appropriate metals was investigated in detail. The influence of the process parameters such as: chemical peculiarities, composition of source hydrides, phase transformation during dehydrogenation, etc. on the alloys formation were established. The binary and tertiary alloys of α and ω phases: Ti 0 .8Zr 0 .8; Ti 0 .66Zr 0 .33; Ti 0 .3Zr 0 .8; Ti 0 .2Zr 0 .8; Ti 0 .8Hf 0 .2; Ti 0 .6Hf 0 .4Ti 0 .66Zr 0 .23Hf 0 .11; etc were recieved. Using elaborated special hydride cycle, an earlier unknown effective process for formation of alloys of transition metals was realized. The dependence of final alloy structure on the composition of initial mixture and hydrogen content in source hydrides was established

  7. Effect of micro alloying elements on the interfacial reactions between molten aluminum alloy and tool steel

    International Nuclear Information System (INIS)

    Nazari, K.A.; Shabestari, S.G.

    2009-01-01

    The morphology and growth kinetics of intermetallic compounds that are formed in the interface of H13 tool steel and A380 molten aluminum has been investigated through immersion experiments. The effect of addition of micro alloying elements to the melt on the formation and thickness of intermetallic layer was also studied. Microstructural investigation showed that three intermetallic layers formed through the liquid-solid reaction during immersion of steel samples in the liquid aluminum at a temperature of 680 deg. C for the duration time of 2 min to 2.5 h. These intermetallic compounds are Al 8 Fe 2 Si, Al 5 FeSi and Al 12 Fe 5 Si. The effect of nitride coating of the surface of H13 steel on the growth of intermetallic phases has also been studied. Micro alloying elements such as strontium and titanium have been used in the melt and their effects on the morphology of intermetallic compound and their growth rate have been investigated by the immersion experiments at the temperature of 680 deg. C for the time of 0.5-2.5 h. The results showed that two layers of Al 8 Fe 2 Si and Al 5 FeSi formed at the interface and Al 12 Fe 5 Si layer was not observed. Nitride coating decreased the overall thickness of the intermetallic layer about 50% after immersion time of 0.5 h. Addition of micro alloying elements such as Sr (0.05 wt%) and Ti (0.2 wt%) to the melt decreased the total thickness of the intermetallic layer about 31% after immersion of steel for 0.5 h in the melt. Both nitride coating and addition of strontium (0.05 wt%) and titanium (0.2 wt%) micro alloying elements to the melt had the most influence on decreasing the overall thickness of the intermetallic layer. The thickness of the intermetallic layer decreased about 60% after immersion of steel for 2.5 h in the aluminum melt. The experimental results clearly indicate the beneficial effect of strontium on the kinetics of the formation and growth of the intermetallic layers.

  8. Optimization of Micro-Alloying Elements for Mechanical Properties in Normalized Cast Steel Using Taguchi Technique

    Directory of Open Access Journals (Sweden)

    Chokkalingam B.

    2017-06-01

    Full Text Available In this study, Taguchi method is used to find out the effect of micro alloying elements like vanadium, niobium and titanium on the hardness and tensile strength of the normalized cast steel. Based on this method, plan of experiments were made by using orthogonal arrays to acquire the data on hardness and tensile strength. The signal to noise ratio and analysis of variance (ANOVA are used to investigate the effect of these micro alloying elements on these two mechanical properties of the micro alloyed normalized cast steel. The results indicated that in the micro alloyed normalized cast steel both these properties increases when compared to non-micro-alloyed normalized cast steel. The effect of niobium addition was found to be significantly higher to obtain higher hardness and tensile strength when compared to other micro alloying elements. The maximum hardness of 200HV and the maximum tensile strength of 780 N/mm2 were obtained in 0.05%Nb addition micro alloyed normalized cast steel. Micro-alloyed with niobium normalized cast steel have the finest and uniform microstructure and fine pearlite colonies distributed uniformly in the ferrite. The optimum condition to obtain higher hardness and tensile strength were determined. The results were verified with experiments.

  9. Cathodic protection of steel by electrodeposited zinc-nickel alloy coatings

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, K.R.; Smith, C.J.E. [Defence Research Agency, Farnborough (United Kingdom). Structural Materials Centre; Robinson, M.J. [Cranfield Univ. (United Kingdom). School of Industrial and Manufacturing Science

    1995-12-01

    The ability of electrodeposited zinc-nickel alloy coatings to cathodically protect steel was studied in dilute chloride solutions. The potential distribution along steel strips partly electroplated with zinc-nickel alloys was determined, and the length of exposed steel that was held below the minimum protection potential (E{sub prot}) was taken as a measure of the level of cathodic protection (CP) provided by the alloy coatings. The level of CP afforded by zinc alloy coatings was found to decrease with increasing nickel content. When nickel content was increased to {approx} {ge} 21 wt%, no CP was obtained. Surface analysis of uncoupled zinc-nickel alloys that were immersed in sodium chloride (NaCl) solutions showed the concentration of zinc decreased in the surface layers while the concentration of nickel increased, indicating that the alloys were susceptible to dezincification. The analysis of zinc-nickel alloy coatings on partly electroplated steel strips that were immersed in chloride solution showed a significantly higher level of dezincification than that found for uncoupled alloy coatings. This effect accounted for the rapid loss of CP afforded to steel by some zinc alloy coatings, particularly those with high initial nickel levels.

  10. Discontinuous structural phase transition of liquid metal and alloys (2)

    International Nuclear Information System (INIS)

    Wang, Li; Liu, Jiantong

    2004-01-01

    The diameter (d f ) of diffusion fluid cluster before and after phase transition has been calculated in terms of the paper ''Discontinuous structural phase transition of liquid metal and alloy (1)'' Physics Letters. A 326 (2004) 429-435, to verify quantitatively the discontinuity of structural phase transition; the phenomena of thermal contraction and thermal expansion during the phase transition, together with the evolution model of discontinuous structural phase transition are also discussed in this Letter to explore further the nature of structural transition; In addition, based on the viscosity experimental result mentioned in paper [Y. Waseda, The Structure of Non-Crystalline Materials--Liquids and Amorphous Solids, McGraw-Hill, New York, 1980], we present an approach to draw an embryo of the liquid-liquid (L-L) phase diagram for binary alloys above liquidus in the paper, expecting to guide metallurgy process so as to improve the properties of alloys. The idea that controls amorphous structure and its properties by means of the L-L phase diagram for alloys and by the rapid cooling technique to form the amorphous alloy has been brought forward in the end

  11. Enhancement of Impact Toughness by Delamination Fracture in a Low-Alloy High-Strength Steel with Al Alloying

    Science.gov (United States)

    Sun, Junjie; Jiang, Tao; Liu, Hongji; Guo, Shengwu; Liu, Yongning

    2016-12-01

    The effect of delamination toughening of martensitic steel was investigated both at room and low temperatures [253 K and 233 K (-20 °C and -40 °C)]. Two low-alloy martensitic steels with and without Al alloying were both prepared. Layered structure with white band and black matrix was observed in Al alloyed steel, while a homogeneous microstructure was displayed in the steel without Al. Both steels achieved high strength (tensile strength over 1600 MPa) and good ductility (elongation over 11 pct), but they displayed stark contrasts on impact fracture mode and Charpy impact energy. Delamination fracture occurred in Al alloyed steel and the impact energies were significantly increased both at room temperature (from 75 to 138 J, i.e., nearly improved up to 2 times) and low temperatures [from 47.9 to 71.3 J at 233 K (-40 °C)] compared with the one without Al. Alloying with Al promotes the segregation of Cr, Mn, Si and C elements to form a network structure, which is martensite with higher carbon content and higher hardness than that of the matrix. And this network structure evolved into a band structure during the hot rolling process. The difference of yield stress between the band structure and the matrix gives rise to a delamination fracture during the impact test, which increases the toughness greatly.

  12. Alloying effect on hardening of martensite stainless steels of the Fe-Cr-Ni and Fe-Cr-Co systems

    International Nuclear Information System (INIS)

    Fel'dgandler, Eh.G.; Savkina, L.Ya.

    1975-01-01

    The effect of alloying elements is considered on the γ → a-transformation and hardening of certain compositions of the ternary Fe-Cr-Ni- and Fe-Cr-Co alloy systems with the martensite structure. In martensite Fe-(10 to 14)% Cr base steels the elements Co, Cu, W, Ni, Mo, Si, Cr decrease, Mn, Si, Mo, Cu increase, and Cr, Ni, Co decrease the temperature of α → γ-transition. The tempering of martensite steels of the Fe-Cr-Ni- and Fe-Cr-Co-systems containing 10 to 14% Cr, 4 to 9% Ni, and 7 to 12% Co does not lead to hardening. Alloyage of the martensite Fe-Cr-Ni-, Fe-Cr-Co- and Fe-Cr-Ni-Co base separately with Mo, W, Si or Cu leads to a hardening during tempering, the hardening being the higher, the higher is the content of Ni and, especially, of Co. The increase in the content of Mo or Si produces the same effect as the increase in the Co content. In on Fe-Cr-Co or Fe-Cr-Ni-Co based steels alloyed with Mo or Si, two temperature ranges of ageing have been revealed which, evidently, have different hardening natures. The compositions studied could serve as the base material for producing maraging stainless steels having a complex variety of properties

  13. Temperature and environmentally assisted cracking in low alloy steel

    International Nuclear Information System (INIS)

    Auten, T.A.; Monter, J.V.

    1995-04-01

    Environmental assisted cracking (EAC) can be defined as the propagation of fatigue cracks in water at rates from 3 to over 40 times the growth rates in air. For low alloy steels with sulfur contents > 0.0125% by weight, EAC is normal behavior in the 240 to 290C range. However, literature yields mixed results for low alloy steels with compositions just below this sulfur level; some reports indicate EAC while others do not. Also, several authors have reported an increased tendency toward EAC when the water temperatures were lowered. In the present work, five ASTM A 508 Class 2 forgings with ladle and check analyses that ranged from 0.010 to 0.019 wt% S were tested in high purity deaerated water in the temperature range of 93 to 260C. At 260C these forgings did not exhibit EAC, reinforcing earlier results for two similar forgings. This broad sampling indicates strong resistance to EAC for this class of forging at 260C. On the other hand, EAC occurred consistently in the three of these forgings that were tested below 204C, provided the test conditions (loading frequency, ΔK, and R) were high enough to produce a high baseline fatigue crack growth rate (FCGR), where the baseline FCGR is that expected in air. At 149C, EAC occurred at test conditions that combined to yield a baseline FCGR greater than ∼2E-6 mm/s. At 204, 121, and 93C, this critical crack growth rate appeared to shift to lower baseline values. The EAC that occurred at lower temperatures was a factor of 3 to 12 times higher than baseline air rates, which was not as strong as the effect for higher sulfur steels at 240 to 290C. Also, no plateau in the growth rates occurred as it does with the higher sulfur steels. In another approach, EAC was induced at 93 and at 260C by raising the dissolved oxygen content of the water from 15 ppb

  14. Effect of Aluminum Alloying on the Hot Deformation Behavior of Nano-bainite Bearing Steel

    Science.gov (United States)

    Yang, Z. N.; Dai, L. Q.; Chu, C. H.; Zhang, F. C.; Wang, L. W.; Xiao, A. P.

    2017-12-01

    Interest in using aluminum in nano-bainite steel, especially for high-carbon bearing steel, is gradually growing. In this study, GCr15SiMo and GCr15SiMoAl steels are introduced to investigate the effect of Al alloying on the hot deformation behavior of bearing steel. Results show that the addition of Al not only notably increases the flow stress of steel due to the strong strengthening effect of Al on austenite phase, but also accelerates the strain-softening rates for its increasing effect on stacking fault energy. Al alloying also increases the activation energy of deformation. Two constitutive equations with an accuracy of higher than 0.99 are proposed. The constructed processing maps show the expanded instability regions for GCr15SiMoAl steel as compared with GCr15SiMo steel. This finding is consistent with the occurrence of cracking on the GCr15SiMoAl specimens, revealing that Al alloying reduces the high-temperature plasticity of the bearing steel. On the contrary, GCr15SiMoAl steel possesses smaller grain size than GCr15SiMo steel, manifesting the positive effect of Al on bearing steel. Attention should be focused on the hot working process of bearing steel with Al.

  15. Novel Dissimilar Joints Between Alloy 800H and 2.25%Cr and 1%Mo Steel

    Energy Technology Data Exchange (ETDEWEB)

    DebRoy, Tarasankar

    2017-12-31

    Dissimilar metal joints between ferritic steels and nickel base alloys are currently fabricated using conventional arc welding processes with selected filler metal combinations. The dissimilar metal joints contain abrupt changes in composition over a relatively small distance. Many years of service at elevated temperatures has shown that these welds are susceptible to creep and creep fatigue failures. The primary mechanism for these creep failures involves carbon diffusion from the ferritic steel to the nickel base alloy. As a result, a carbon depleted zone is created that contains very few stable carbides. This work used additive manufacturing (AM) technologies as a highly controllable means for reducing carbon migration through theoretically designed, compositionally graded transition joints guided by appropriate thermodynamic, kinetic and heat transfer and fluid flow modeling. The contents of the report include the objectives and tasks set forth by the PI and collaborators, major technical accomplishments throughout the research and additional details in the form of technical publications resulting from the NEUP grant and reports from the collaborating university and national laboratory.

  16. Grain boundary phosphorus segregation under thermal aging in low alloy steels

    International Nuclear Information System (INIS)

    Nakata, Hayato; Fujii, Katsuhiko; Fukuya, Koji; Kasada, Ryuta; Kimura, Akihiko

    2007-01-01

    Intergranular embrittlement due to grain boundary segregation of phosphorus is recognized as one of the potential degradation factors in irradiated reactor low alloy steels at high neutron fluence. In this study, low alloy steels thermally aged at 400-500degC were investigated to evaluate the correlation between phosphorus segregation and intergranular embrittlement. Phosphorus segregation determined using Auger electron spectroscopy increased after thermal aging above 450degC and was in good agreement with the calculated value based on McLean's model. No influence of thermal aging on tensile properties or hardness was observed. The ductile brittle transition temperature determined using a one-third size Charpy impact test increased at a P/Fe peak ratio of 0.14. These results indicated that there is a threshold level of phosphorus segregation for non-hardening embrittlement. DBTT increased with the proportion of intergranular fracture, so this result shows that there is a relationship between DBTT and the properties of intergranular fracture. The fracture stress decreases due to non-hardening embrittlement on the thermally aged material with high proportion of intergranular fracture. (author)

  17. Friction Welding of Aluminium and Aluminium Alloys with Steel

    Directory of Open Access Journals (Sweden)

    Andrzej Ambroziak

    2014-01-01

    Full Text Available The paper presents our actual knowledge and experience in joining dissimilar materials with the use of friction welding method. The joints of aluminium and aluminium alloys with the different types of steel were studied. The structural effects occurring during the welding process were described. The mechanical properties using, for example, (i microhardness measurements, (ii tensile tests, (iii bending tests, and (iv shearing tests were determined. In order to obtain high-quality joints the influence of different configurations of the process such as (i changing the geometry of bonding surface, (ii using the interlayer, or (iii heat treatment was analyzed. Finally, the issues related to the selection of optimal parameters of friction welding process were also investigated.

  18. Process to determine light elements content of steel and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Quintella, Cristina M.A.L.T.M.H.; Castro, Martha T.P.O. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica. LabLaser; Mac-Culloch, Joao N.L.M. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The present work reports a process to determine qualitatively and quantitatively elements of molar mass inferior to 23 within materials, by X rays spectra associated with multivariate data analysis, or chemometric analysis. The spectra is acquired between 5 keV and 22 keV when the materials are exposed to X radiation. Here is reported the direct determination of carbon content in steel and metallic alloys. The process is more effective when using spectral regions which are not usually used. From the analysis of these spectral regions which were not considered before, it was possible to detect light elements with molar mass lower than 23, which have low capacity of absorbing and emitting radiation, but have high capacity of scattering radiation. The process here reported has the advantage that X-Ray spectra obtained are calibrated multivariately, showing high potential for development in order to be used in a portable field equipment. (author)

  19. Dependence of magnetic permeability on residual stresses in alloyed steels

    Directory of Open Access Journals (Sweden)

    E. Hristoforou

    2018-04-01

    Full Text Available A method for the monitoring of residual stress distribution in steels has been developed based on non-destructive surface magnetic permeability measurements. In order to investigate the potential utilization of the magnetic method in evaluating residual stresses, the magnetic calibration curves of various ferromagnetic alloyed steels’ grade (AISI 4140, TRIP and Duplex were examined. X-Ray diffraction technique was used for determining surface residual stress values. The overall measurement results have shown that the residual stress determined by the magnetic method was in good agreement with the diffraction results. Further experimental investigations are required to validate the preliminary results and to verify the presence of a unique normalized magnetic stress calibration curve.

  20. Systematic corrosion investigation of various Cu-Sn alloys electrodeposited on mild steel in acidic solution: Dependence of alloy composition

    Energy Technology Data Exchange (ETDEWEB)

    Suerme, Yavuz, E-mail: ysurme@nigde.edu.t [Department of Chemistry, Faculty of Science and Art, Nigde University, 51200 Nigde (Turkey); Guerten, A. Ali [Department of Chemistry, Faculty of Science and Art, Osmaniye Korkut Ata University, 80000 Osmaniye (Turkey); Bayol, Emel; Ersoy, Ersay [Department of Chemistry, Faculty of Science and Art, Nigde University, 51200 Nigde (Turkey)

    2009-10-19

    Copper-tin alloy films were galvanostatically electrodeposited on the mild steel (MS) by combining the different amount of Cu and Sn electrolytes at a constant temperature (55 deg. C) and pH (3.5). Alloy films were characterized by using the energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and micrographing techniques. Corrosion behaviours were evaluated with electrochemical impedance spectrometry (EIS) and electrochemical polarization measurements. Time gradient of electrolysis process was adjusted to obtain same thickness of investigated alloys on MS. The systematic corrosion investigation of various Cu{sub x}-Sn{sub 100-x} (x = 0-100) alloy depositions on MS substrate were carried out in 0.1 M sulphuric acid medium. Results indicate that the corrosion resistance of the alloy coatings depended on the alloy composition, and the corrosion resistance increased at Cu-Sn alloy deposits in proportion to Sn ratio.

  1. A study of the formation of Cr-surface alloyed layer on structural alloy steel by Co2 laser

    International Nuclear Information System (INIS)

    Kim, T.H.; Han, W.S.

    1986-01-01

    In order to improve wear and erosion-resistances of a structural alloy steel (SNCM 8) during heat-cycling, chromium-alloyed layers were produced on the surface by irradiating Co 2 laser. Specimens were prepared either by electroplating of hard-chromium or coating of chromium powders on the steel followed by the laser treatment. Index values, which related the depth and the width of the alloyed layers to the scanning speed of laser, for both samples are experimentally measured. At a fixed scanning speed, while both samples resulted in a similar depth of the alloyed layers, the chromium powder coated specimen showed larger width of the alloyed layer than the chromium electroplated one. The hardness values of the alloyed layers in both samples were slightly lower than that of the martensitic region beneath the alloyed layers. But they are considerably higher than those of steel matrices. Regardless of the prior treatments before laser irradiation, distributions of chromium were fairly uniform throughout the alloyed layers. (Author)

  2. Effect of decreased hot-rolling reduction treatment on fracture toughness of low-alloy structural steels

    Science.gov (United States)

    Tomita, Yoshiyuki

    1990-09-01

    Commercial low-alloy structural steels, 0.45 pct C (AISI 1045 grade), 0.40 pct C-Cr-Mo (AISI 4140 grade), and 0.40 pct C-Ni-Cr-Mo (AISI 4340 grade), have been studied to determine the effect of the decreased hot-rolling reduction treatment (DHRRT) from 98 to 80 pct on fracture toughness of quenched and highly tempered low-alloy structural steels. The significant conclusions are as follows: (1) the sulfide inclusions were modified through the DHRRT from a stringer (mean aspect ratio: 16.5 to 17.6) to an ellipse (mean aspect ratio: 3.8 to 4.5), independent of the steels studied; (2) the DHRRT significantly improved J Ic in the long-transverse and shorttransverse orientations, independent of the steels studied; and (3) the shelf energy in the Charpy V-notch impact test is also greatly improved by the DHRRT, independent of testing orientation and steels studied; however, (4) the ductile-to-brittle transition temperature was only slightly affected by the DHRRT. The beneficial effect on the J Ic is briefly discussed in terms of a crack extension model involving the formation of voids at the inclusion sites and their growth and eventual linking up through the rupture of the intervening ligaments by local shear.

  3. Proceedings of the eleventh international conference on high nitrogen steels and interstitial alloys: souvenir

    International Nuclear Information System (INIS)

    2012-01-01

    Stainless steels serve a multitude of applications from brightly polished consumer products to machinery and equipment for challenging industrial environments. Improvements of mechanical and corrosion properties of stainless steels and a whole spectrum of steels for high pressure and high temperature applications, necessitated development of new elegant class of High Nitrogen Steels (HNS). Presently high nitrogen steels occupy a centre stage in many strategic industries like power, oil and gas and infrastructure etc. In nuclear industry, in the demanding environments of fuel reprocessing and waste managing plants HNS can find possible applications. Already nitrogen alloyed stainless steel has found its niche as structural material of Fast Breeder Reactors and Advanced Heavy Water Reactor in India. Nitrogen is also an important alloying element in the new generation ferritic steels meant for high temperature applications. Papers relevant to INIS are indexed separately

  4. Ferromagnetism and spin glass ordering in transition metal alloys (invited)

    Science.gov (United States)

    Crane, S.; Carnegie, D. W., Jr.; Claus, H.

    1982-03-01

    Magnetic properties of transition metal alloys near the percolation threshold are often complicated by metallurgical effects. Alloys like AuFe, VFe, CuNi, RhNi, and PdNi are in general not random solid solutions but have various degrees of atomic clustering or short-range order (SRO), depending on the heat treatment. First, it is shown how the magnetic ordering temperature of these alloys varies with the degree of clustering or SRO. Second, by systematically changing this degree of clustering or SRO, important information can be obtained about the magnetic phase diagram. In all these alloys below the percolation limit, the onset of ferromagnetic order is probably preceded by a spin glass-type ordering. However, details of the magnetic phase diagram near the critical point can be quite different alloy systems.

  5. Cyclic deformation behavior of steels and light-metal alloys

    International Nuclear Information System (INIS)

    Walther, Frank; Eifler, Dietmar

    2007-01-01

    The detailed knowledge of the cyclic deformation behavior of metallic materials is an essential condition for the comprehensive understanding of fatigue mechanisms and a reliable lifetime calculation of cyclically loaded specimens and components. Various steels and light-metal alloys were investigated under stress and strain control on servohydraulic testing systems. In addition to mechanical stress-strain hysteresis measurements, the changes of the specimen temperature and the electrical resistance due to plastic deformation processes were measured. The plasticity-induced martensite formation in metastable austenitic steels was detected in situ with a ferritescope sensor. As advanced magnetic measuring technique giant-magneto-resistance sensors in combination with an universal eddy-current equipment were used for the on-line monitoring of fatigue processes. Due to their direct dependence on microstructural changes, all physical values show a clear interaction with the actual fatigue state. The results of the plastic strain, thermometric, electric and magnetic measuring techniques were presented versus the number of cycles as well as in Morrow and Coffin-Manson plots. The microstructures were characterized by scanning electron microscopy

  6. Cyclic deformation behavior of steels and light-metal alloys

    Energy Technology Data Exchange (ETDEWEB)

    Walther, Frank [University of Kaiserslautern, Institute of Materials Science and Engineering, P.O. Box 3049, D-67653 Kaiserslautern (Germany)], E-mail: walther@mv.uni-kl.de; Eifler, Dietmar [University of Kaiserslautern, Institute of Materials Science and Engineering, P.O. Box 3049, D-67653 Kaiserslautern (Germany)

    2007-11-15

    The detailed knowledge of the cyclic deformation behavior of metallic materials is an essential condition for the comprehensive understanding of fatigue mechanisms and a reliable lifetime calculation of cyclically loaded specimens and components. Various steels and light-metal alloys were investigated under stress and strain control on servohydraulic testing systems. In addition to mechanical stress-strain hysteresis measurements, the changes of the specimen temperature and the electrical resistance due to plastic deformation processes were measured. The plasticity-induced martensite formation in metastable austenitic steels was detected in situ with a ferritescope sensor. As advanced magnetic measuring technique giant-magneto-resistance sensors in combination with an universal eddy-current equipment were used for the on-line monitoring of fatigue processes. Due to their direct dependence on microstructural changes, all physical values show a clear interaction with the actual fatigue state. The results of the plastic strain, thermometric, electric and magnetic measuring techniques were presented versus the number of cycles as well as in Morrow and Coffin-Manson plots. The microstructures were characterized by scanning electron microscopy.

  7. Austenite Grain Growth Behavior of AISI 4140 Alloy Steel

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2013-01-01

    Full Text Available AISI 4140 alloy steel is widely applied in the manufacture of various parts such as gears, rams, and spindles due to its good performance of strength, toughness, and wear resistance. The former researches most focused on its deformation and recrystallization behaviors under high temperature. However, the evolution laws of austenite grain growth were rarely studied. This behavior also plays an important role in the mechanical properties of parts made of this steel. In this study, samples are heated to a certain temperature of 1073 K, 1173 K, 1273 K, and 1373 K at a heating rate of 5 K per second and hold for different times of 0 s, 120 s, 240 s, 360 s, and 480 s before being quenched with water. The experimental results suggest that the austenite grains enlarge with increasing temperature and holding time. A mathematical model and an application developed in Matlab environment are established on the basis of previous works and experimental results to predict austenite grains size in hot deformation processes. The predicted results are in good agreement with experimental results which indicates that the model and the application are reliable.

  8. Charge transfers in complex transition metal alloys (Ti2Fe)

    International Nuclear Information System (INIS)

    Abramovici, G.

    1998-01-01

    We introduce a new non-orthogonal tight-binding model, for complex alloys, in which electronic structure is characterized by charge transfers. We give the analytic calculation of a charge transfer, in which overlapping two-center terms are rigorously taken into account. Then, we apply numerically this result to an approximant phase of a quasicrystal of Ti 2 Fe alloy. This model is more particularly adapted to transition metals, and gives realistic densities of states. (orig.)

  9. The energetics of ordered intermetallic alloys (of the transition metals)

    International Nuclear Information System (INIS)

    Watson, R.E.; Weinert, M.; Davenport, J.W.; Fernando, G.W.; Bennett, L.H.

    1992-01-01

    The atomically ordered phases in ordered transition metal alloys are discussed. This chapter is divided into: physical parameters controlling phase stability (Hume-Rothery, structural maps, Miedema Hamiltonian), wave functions ampersand band theory, comment on entropy terms, cohesive energies (electron promotion energies, Hund's rule on orbital effects), structural energies/stabilities of elemental solids, total energies and atomic positions, charge transfer (Au alloys, charge tailing), heats of formation of ordered compounds

  10. Alloys influence in ferritic steels with hydrogen attack

    International Nuclear Information System (INIS)

    Moro, L; Rey Saravia, D; Lombardich, J; Saggio, M; Juan, A; Blanco, J

    2003-01-01

    Materials exposed to a corrosive environment and high temperatures, are associated with a decrease of their mechanical properties and embitterment.At room temperatures atomic hydrogen diffuses easily through metals structure, it accumulates in lattice defects forming molecular hydrogen and generating cracking due to internal stresses.Under high temperatures the phenomenon is more complex.The steels in these conditions present different structures of precipitates, that the change under creep conditions period.In this work it is determined the influence of Cr and V alloys, the changes of ferritic steel resistance in a corrosive environment and high temperatures.1.25 Cr 1 Mo 0.25 V and 2.25Cr 1 Mo under different loads and temperatures previously attacked by hydrogen environment.The hydrogen is induced by the electrolytic technique, optimizing the choice of temperatures, current density, electrolyte, etc. In order to control an adequate cathode charge, a follow up procedure is carried out by electronic barrier microscopy.After the attack, the material is settled at room temperatures for certain period of time, to allow the hydrogen to leave and evaluate the residual damage.Creep by torsion assays, under constant load and temperature is used as an experimental technique.With the outcome data curves are drawn in order to study the secondary creep rate, with the applied load and temperature, determining the value of stress exponent n and the activation energy Q.Comparing to equal assays to the same ferritic steels but non attacked by hydrogen, these values allows the prediction of microstructure changes present during these tests

  11. Determination of tungsten in high-alloy steels and heat resisting alloys by isotope dilution-spark source mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa; Yamada, Kei; Okochi, Haruno; Hirose, Fumio

    1983-01-01

    Tungsten in high-alloy steels and heat-resisting alloys was determined by isotope dilution method combined with spark source mass spectrometry by using 183 W enriched tungsten. The spike solution was prepared by fusing tungsten trioxide in sodium carbonate. A high-alloy steel sample was dissolved in the mixture of sulfuric acid and phosphoric acid together with the spike solution; a sample of heat resisting alloy was similarly dissolved in the mixture of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid. The solution was evaporated to give dense white fumes. Tungsten was separated from the residue by a conventional cinchonine salt-precipitation method. The salt was ignited, and the residue was mixed with graphite powder and pressed into electrodes. The isotope 183 W and 184 W were measured. The method was applied to the determination of tungsten in JSS and NBS standard high-alloy steels and JAERI standard nickel- and NBS standard cobalt-base heat resisting alloys containing more than 0.05% tungsten. The results were obtained with satisfactory precision and accuracy. However, the results obtained for JSS standard high- speed steels containing molybdenum tended to be significantly lower than the certified values. (author)

  12. Corrosion Behavior and Durability of Low-Alloy Steel Rebars in Marine Environment

    Science.gov (United States)

    Liu, Ming; Cheng, Xuequn; Li, Xiaogang; Yue, Pan; Li, Jun

    2016-11-01

    The corrosion resistance of Cr-modified low-alloy steels and HRB400 carbon steel was estimated using the open-circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopic, and weight loss methods in simulated concrete pore solution. Results show that Cr-modified steels exhibit a higher corrosion resistance with a higher critical chloride level (CTL), lower corrosion current density, and higher impedance than carbon steel. The CTL of the steels significantly reduces with increasing temperature. Weight loss measurement shows that the Cr-modified steels exhibit low corrosion rates and small corrosion pitting. The primary constituents of the corrosion scales are Fe2O3, Fe3O4, β-FeOOH, γ-FeOOH, and α-FeOOH. A large amount of α-FeOOH could be detected in the Cr-modified steel corrosion products. Moreover, the Cr-modified steels demonstrate a higher durability than HRB400 carbon steel.

  13. Fracture assessment for a dissimilar metal weld of low alloy steel and Ni-base alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Takuya, E-mail: takuya4.ogawa@toshiba.co.jp [Toshiba Corporation Power Systems Company, Power and Industrial Systems Research and Development Center, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8523 (Japan); Itatani, Masao; Saito, Toshiyuki; Hayashi, Takahiro; Narazaki, Chihiro; Tsuchihashi, Kentaro [Toshiba Corporation Power Systems Company, Power and Industrial Systems Research and Development Center, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8523 (Japan)

    2012-02-15

    Recently, instances of SCC in Ni-base alloy weld metal of light water reactor components have been reported. Despite the possibility of propagation of SCC crack to the fusion line between low alloy steel (LAS) of pressure vessel and Ni-base alloy of internal structure, a fracture assessment method of dissimilar metal welded joint has not been established. The objective of this study is to investigate a fracture mode of dissimilar metal weld of LAS and Ni-base alloy for development of a fracture assessment method for dissimilar metal weld. Fracture tests were conducted using two types of dissimilar metal weld test plates with semi-elliptical surface crack. In one of the test plates, the fusion line lies around the surface points of the surface crack and the crack tips at the surface points have intruded into LAS. Material ahead of the crack tip at the deepest point is Ni-base alloy. In the other, the fusion line lies around the deepest point of the surface crack and the crack tip at the deepest point has intruded into LAS. Material ahead of the crack tip at the deepest point is LAS. The results of fracture tests using the former type of test plate reveal that the collapse load considering the proportion of ligament area of each material gives a good estimation for fracture load. That is, fracture assessment based on plastic collapse mode is applicable to the former type of test plate. It is also understood that a fracture assessment method based on the elastic-plastic fracture mode is suitable for the latter type of test plate.

  14. Galvanic Interaction between Chalcopyrite and Pyrite with Low Alloy and High Carbon Chromium Steel Ball

    Directory of Open Access Journals (Sweden)

    Asghar Azizi

    2013-01-01

    Full Text Available This study was aimed to investigate the galvanic interaction between pyrite and chalcopyrite with two types of grinding media (low alloy and high carbon chromium steel ball in grinding of a porphyry copper sulphide ore. Results indicated that injection of different gases into mill altered the oxidation-reduction environment during grinding. High carbon chromium steel ball under nitrogen gas has the lowest galvanic current, and low alloy steel ball under oxygen gas had the highest galvanic current. Also, results showed that the media is anodic relative to pyrite and chalcopyrite, and therefore pyrite or chalcopyrite with a higher rest potential acted as the cathode, whilst the grinding media with a lower rest potential acted as the anode, when they are electrochemically contacted. It was also found that low alloy steel under oxygen produced the highest amount of EDTA extractable iron in the slurry, whilst high carbon chromium steel under nitrogen atmosphere led to the lowest amount.

  15. Comparative estimation of weld-ability of medium-alloy steels

    International Nuclear Information System (INIS)

    Makarov, Eh.L.; Laz'ko, V.E.

    1977-01-01

    Weldability of various industrial steels has been investigated as affected by mutual presence of carbon and alloying elements in a wide range of concentrations. Mechanical properties and technological strength of medium alloyed steel welded joints have been compared. Technological strength parameters have been found to sharply decrease with increasing carbon content, the decrease depending on the alloying system. Resistance to hot and cold cracking is somewhat decreased by nickel and increased by molibdenum and tungsten. The best mechanical properties are displayed by steels of the Kh2GSNVM type. Industrial evidence on argon arc welding of different constructions made of steels 1.5-20 mm thick is compared to laboratory results. Accordingly, the high strength steels are divided into three groups, i.e. those manifesting good, satisfactory and poor weldability

  16. Overview of research trends and problems on Cr-Mo low alloy steels for pressure vessel

    International Nuclear Information System (INIS)

    Chi, Byung Ha; Kim, Jeong Tae

    2000-01-01

    Cr-Mo low alloy steels have been used for a long time for pressure vessel due to its excellent corrosion resistance, high temperature strength and toughness. The paper reviewed the latest trends on material development and some problems on Cr-Mo low alloy steel for pressure vessel, such as elevated temperature strength, hardenability, synergetic effect between temper and hydrogen embrittlement, hydrogen attack and hydrogen induced disbonding of overlay weld-cladding

  17. Microstructural characterisation of friction stir welding joints of mild steel to Ni-based alloy 625

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J. [Brazilian Nanotechnology National Laboratory (LNNano), P.O. Box 6192, Campinas, SP (Brazil); University of Campinas (UNICAMP), Campinas, SP (Brazil); Ramirez, A.J., E-mail: ramirezlondono.1@osu.edu [Brazilian Nanotechnology National Laboratory (LNNano), P.O. Box 6192, Campinas, SP (Brazil); University of Campinas (UNICAMP), Campinas, SP (Brazil); Department of Materials Science and Engineering, The Ohio State University — OSU, Columbus, OH 43221 (United States)

    2015-12-15

    In this study, 6-mm-thick mild steel and Ni-based alloy 625 plates were friction stir welded using a tool rotational speed of 300 rpm and a travel speed of 100 mm·min{sup −1}. A microstructural characterisation of the dissimilar butt joint was performed using optical microscopy, scanning and transmission electron microscopy, and energy dispersive X-ray spectroscopy (XEDS). Six different weld zones were found. In the steel, the heat-affected zone (HAZ) was divided into three zones and was composed of ferrite, pearlite colonies with different morphologies, degenerated regions of pearlite and allotriomorphic and Widmanstätten ferrite. The stir zone (SZ) of the steel showed a coarse microstructure consisting of allotriomorphic and Widmanstätten ferrite, degenerate pearlite and MA constituents. In the Ni-based alloy 625, the thermo-mechanically affected zone (TMAZ) showed deformed grains and redistribution of precipitates. In the SZ, the high deformation and temperature produced a recrystallised microstructure, as well as fracture and redistribution of MC precipitates. The M{sub 23}C{sub 6} precipitates, present in the base material, were also redistributed in the stir zone of the Ni-based alloy. TMAZ in the steel and HAZ in the Ni-based alloy could not be identified. The main restorative mechanisms were discontinuous dynamic recrystallisation in the steel, and discontinuous and continuous dynamic recrystallisation in the Ni-based alloy. The interface region between the steel and the Ni-based alloy showed a fcc microstructure with NbC carbides and an average length of 2.0 μm. - Highlights: • Comprehensive microstructural characterisation of dissimilar joints of mild steel to Ni-based alloy • Friction stir welding of joints of mild steel to Ni-based alloy 625 produces sound welds. • The interface region showed deformed and recrystallised fcc grains with NbC carbides and a length of 2.0 μm.

  18. Effect of N+Cr alloying on the microstructures and tensile properties of Hadfield steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, F.C., E-mail: zfc@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004 (China); Wang, F. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, H.; Yu, B.D. [China Railway Shanhaiguan Bridge Group Co. LTD, Qinhuangdao 066205 (China)

    2017-01-02

    The microstructures and tensile behaviors of traditional Hadfield steel, named Mn12 steel, and Hadfield steel alloyed with N+Cr, named Mn12CrN steel were studied through optical microscopy, transmission electron microscopy, and scanning electron microscopy, among others. Three different tensile strain rates of 5×10{sup −4}, 5×10{sup −3}, and 5×10{sup −2} s{sup −1} were selected in the tensile test. The deformation microstructures and fracture morphologies of the two steels after fracture in the tensile test were observed to analyze the tensile deformation response to different tensile strain rates. Results showed that the grain size of Mn12CrN steel was evidently refined after alloying with N+Cr. The grain would not become abnormally coarse even with increasing austenitizing temperature. During tensile deformation, the strength and plasticity of Mn12CrN steel were superior to those of Mn12 steel at the same strain rate. With increasing the strain rate, the changes in strength and plasticity of Mn12CrN steel were less sensitive to tensile strain rate compared with Mn12 steel. The effects of grain refinement and N+Cr alloying on dynamic strain aging and deformation twining behaviors were responsible for this lack of sensitivity to strain rate.

  19. Effect of N+Cr alloying on the microstructures and tensile properties of Hadfield steel

    International Nuclear Information System (INIS)

    Chen, C.; Zhang, F.C.; Wang, F.; Liu, H.; Yu, B.D.

    2017-01-01

    The microstructures and tensile behaviors of traditional Hadfield steel, named Mn12 steel, and Hadfield steel alloyed with N+Cr, named Mn12CrN steel were studied through optical microscopy, transmission electron microscopy, and scanning electron microscopy, among others. Three different tensile strain rates of 5×10 −4 , 5×10 −3 , and 5×10 −2 s −1 were selected in the tensile test. The deformation microstructures and fracture morphologies of the two steels after fracture in the tensile test were observed to analyze the tensile deformation response to different tensile strain rates. Results showed that the grain size of Mn12CrN steel was evidently refined after alloying with N+Cr. The grain would not become abnormally coarse even with increasing austenitizing temperature. During tensile deformation, the strength and plasticity of Mn12CrN steel were superior to those of Mn12 steel at the same strain rate. With increasing the strain rate, the changes in strength and plasticity of Mn12CrN steel were less sensitive to tensile strain rate compared with Mn12 steel. The effects of grain refinement and N+Cr alloying on dynamic strain aging and deformation twining behaviors were responsible for this lack of sensitivity to strain rate.

  20. Fe-Cr-V ternary alloy-based ferritic steels for high- and low-temperature applications

    International Nuclear Information System (INIS)

    Rieth, M.; Materna-Morris, E.; Dudarev, S.L.; Boutard, J.-L.; Keppler, H.; Mayor, J.

    2009-01-01

    The phase stability of alloys and steels developed for application in nuclear fission and fusion technology is one of the decisive factors determining the potential range of operating temperatures and radiation conditions that the core elements of a power plant can tolerate. In the case of ferritic and ferritic-martensitic steels, the choice of the chemical composition is dictated by the phase diagram for binary FeCr alloys where in the 0-9% range of Cr composition the alloy remains in the solid solution phase at and below the room temperature. For Cr concentrations exceeding 9% the steels operating at relatively low temperatures are therefore expected to exhibit the formation of α' Cr-rich precipitates. These precipitates form obstacles for the propagation of dislocations, impeding plastic deformation and embrittling the material. This sets the low temperature limit for the use of of high (14% to 20%) Cr steels, which for the 20% Cr steels is at approximately 600 deg. C. On the other hand, steels containing 12% or less Cr cannot be used at temperatures exceeding ∼600 deg. C due to the occurrence of the α-γ transition (912 deg. C in pure iron and 830 deg. C in 7% Cr alloy), which weakens the steel in the high temperature limit. In this study, we investigate the physical properties of a concentrated ternary alloy system that attracted relatively little attention so far. The phase diagram of ternary Fe-Cr-V alloy shows no phase boundaries within a certain broad range of Cr and V concentrations. This makes the alloy sufficiently resistant to corrosion and suggests that steels and dispersion strengthened materials based on this alloy composition may have better strength and stability at high temperatures. Experimental heats were produced on a laboratory scale by arc melting the material components to pellets, then by melting the pellets in an induction furnace and casting the melt into copper moulds. The compositions in weight percent (iron base) are 10Cr5V, 10Cr

  1. M551 metals melting experiment. [space manufacturing of aluminum alloys, tantalum alloys, stainless steels

    Science.gov (United States)

    Li, C. H.; Busch, G.; Creter, C.

    1976-01-01

    The Metals Melting Skylab Experiment consisted of selectively melting, in sequence, three rotating discs made of aluminum alloy, stainless steel, and tantalum alloy. For comparison, three other discs of the same three materials were similarly melted or welded on the ground. The power source of the melting was an electron beam unit. Results are presented which support the concept that the major difference between ground base and Skylab samples (i.e., large elongated grains in ground base samples versus nearly equiaxed and equal sized grains in Skylab samples) can be explained on the basis of constitutional supercooling, and not on the basis of surface phenomena. Microstructural observations on the weld samples and present explanations for some of these observations are examined. In particular, ripples and their implications to weld solidification were studied. Evidence of pronounced copper segregation in the Skylab A1 weld samples, and the tantalum samples studied, indicates a weld microhardness (and hence strength) that is uniformly higher than the ground base results, which is in agreement with previous predictions. Photographs are shown of the microstructure of the various alloys.

  2. Tensile and impact behaviour of BATMAN II steels, Ti-bearing reduced activation martensitic alloys

    Science.gov (United States)

    Filacchioni, G.; Casagrande, E.; De Angelis, U.; De Santis, G.; Ferrara, D.; Pilloni, L.

    Two series of Reduced Activation Ferrous alloys (RAF) have been produced and studied by Casaccia's Laboratories. These martensitic alloys are named BATMAN steels. They are among the few presently developed RAF materials to exploit Ti as a carbide forming and grain size stabilizing element instead of Ta. In this work their mechanical properties are illustrated.

  3. Use of Nitrocarburizing for Strengthening Threaded Joints of Drill Pipes from Medium-Carbon Alloy Steels

    Science.gov (United States)

    Priymak, E. Yu.; Stepanchukova, A. V.; Yakovleva, I. L.; Tereshchenko, N. A.

    2015-05-01

    Nitrocarburizing is tested at the Drill Equipment Plant for reinforcing threaded joints of drill pipes for units with retrievable core receiver (RCR). The effect of the nitrocarburizing on the mechanical properties of steels of different alloying systems is considered. Steels for the production of threaded joints of drill pipes are recommended.

  4. Prevention of Crevice Corrosion of STS 304 Stainless Steel by a Mg-alloy Galvanic Anode

    International Nuclear Information System (INIS)

    Lim, U. J.; Yun, B. D.; Kim, J. J.

    2006-01-01

    Prevention of crevice corrosion was studied for STS 304 stainless steel using a Mg-alloy galvanic anode in solutions with various specific resistivity. The crevice corrosion and corrosion protection characteristics of the steel was investigated by the electrochemical polarization and galvanic corrosion tests. Experimental results show that the crevice corrosion of STS 304 stainless steel does not occur in solutions of high specific resistivity, but it occurs in solutions of low specific resistivity like in solutions with resistivities of 30, 60 and 115 Ω · m. With decreasing specific resistivity of the solution, the electrode potential of STS 304 stainless steel in the crevice is lowered. The potential of STS 304 stainless steel in the crevice after coupling is cathodically polarized more by decreasing specific resistivity indicating that the crevice corrosion of STS 304 stainless steel is prevented by the Mg-alloy galvanic anode

  5. Comparison of Ductile-to-Brittle Transition Behavior in Two Similar Ferritic Oxide Dispersion Strengthened Alloys

    Science.gov (United States)

    Chao, Jesus; Rementeria, Rosalia; Aranda, Maria; Capdevila, Carlos; Gonzalez-Carrasco, Jose Luis

    2016-01-01

    The ductile-to-brittle transition (DBT) behavior of two similar Fe-Cr-Al oxide dispersion strengthened (ODS) stainless steels was analyzed following the Cottrell–Petch model. Both alloys were manufactured by mechanical alloying (MA) but by different forming routes. One was manufactured as hot rolled tube, and the other in the form of hot extruded bar. The two hot forming routes considered do not significantly influence the microstructure, but cause differences in the texture and the distribution of oxide particles. These have little influence on tensile properties; however, the DBT temperature and the upper shelf energy (USE) are significantly affected because of delamination orientation with regard to the notch plane. Whereas in hot rolled material the delaminations are parallel to the rolling surface, in the hot extruded material, they are randomly oriented because the material is transversally isotropic. PMID:28773764

  6. Comparison of Ductile-to-Brittle Transition Behavior in Two Similar Ferritic Oxide Dispersion Strengthened Alloys.

    Science.gov (United States)

    Chao, Jesus; Rementeria, Rosalia; Aranda, Maria; Capdevila, Carlos; Gonzalez-Carrasco, Jose Luis

    2016-07-29

    The ductile-to-brittle transition (DBT) behavior of two similar Fe-Cr-Al oxide dispersion strengthened (ODS) stainless steels was analyzed following the Cottrell-Petch model. Both alloys were manufactured by mechanical alloying (MA) but by different forming routes. One was manufactured as hot rolled tube, and the other in the form of hot extruded bar. The two hot forming routes considered do not significantly influence the microstructure, but cause differences in the texture and the distribution of oxide particles. These have little influence on tensile properties; however, the DBT temperature and the upper shelf energy (USE) are significantly affected because of delamination orientation with regard to the notch plane. Whereas in hot rolled material the delaminations are parallel to the rolling surface, in the hot extruded material, they are randomly oriented because the material is transversally isotropic.

  7. Thermophysical Property Measurements of Silicon-Transition Metal Alloys

    Science.gov (United States)

    Banish, R. Michael; Erwin, William R.; Sansoucie, Michael P.; Lee, Jonghyun; Gave, Matthew A.

    2014-01-01

    Metals and metallic alloys often have high melting temperatures and highly reactive liquids. Processing reactive liquids in containers can result in significant contamination and limited undercooling. This is particularly true for molten silicon and it alloys. Silicon is commonly termed "the universal solvent". The viscosity, surface tension, and density of several silicon-transition metal alloys were determined using the Electrostatic Levitator system at the Marshall Space Flight Center. The temperature dependence of the viscosity followed an Arrhenius dependence, and the surface tension followed a linear temperature dependence. The density of the melts, including the undercooled region, showed a linear behavior as well. Viscosity and surface tension values were obtain for several of the alloys in the undercooled region.

  8. Role of alloying elements and carbides in the chlorine-induced corrosion of steels and alloys

    Directory of Open Access Journals (Sweden)

    Hans Jürgen Grabke

    2004-03-01

    Full Text Available The high temperature corrosion of steels and Ni-base alloys in oxidizing and chloridizing environments is of practical interest in relation to problems in waste incineration plants and power plants using Cl containing fuels. The behaviour of the most important alloying elements Fe, Cr, Ni, Mo, Mn, Si, Al upon corrosion in an oxidizing and chloridizing atmosphere was elucidated: the reactions and kinetics can be largely understood on the base of thermodynamic data, i.e. free energy of chloride formation, vapor pressure of the chlorides and oxygen pressure pO2 needed for the conversion chlorides -> oxides. The mechanism is described by 'active oxidation', comprising inward penetration of chlorine into the scale, formation of chlorides at the oxide/metal interface, evaporation of the chlorides and conversion of the evaporating chlorides into oxides, which occurs in more or less distance from the surface (depending on pO2. This process leads to loose, fragile, multilayered oxides which are unprotective (therefore: active oxidation. Fe and Cr are rapidly transferred into such scale, Ni and Mo are relatively resistant. In many cases, the grain boundaries of the materials are strongly attacked, this is due to a susceptibility of chromium carbides to chloridation. In contrast the carbides Mo2C, TiC and NbC are less attacked than the matrix. Alloys on the basis Fe-Cr-Si proved to be rather resistant, and the alloying elements Ni and Mo clearly retard the attack in an oxidizing and chloridizing environment.

  9. Comparison of Corrosion Behavior of Low-Alloy Steel Containing Copper and Antimony with 409L Stainless Steel for a Flue Gas Desulfurization System

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun-Ah; Shin, Su-Bin; Kim, Jung-Gu [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-07-15

    The corrosion behavior of low alloy steel containing Cu, Sb and 409L stainless steel was investigated for application in the low-temperature section of a flue gas desulfurization (FGD) system. The electrochemical properties were evaluated by potentiodynamic polarization testing and electrochemical impedance spectroscopy (EIS) in 16.9 vol% H{sub 2}SO{sub 4} + 0.35 vol% HCl at 60 ℃. The inclusions in these steels ere identified by electron probe microanalyzer (EPMA). The corrosion products of the steels were analyzed using scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The corrosion rate of the low alloy steel containing Cu, Sb was about 100 times lower than that of 409L stainless steel. For stainless steel without passivation, active corrosion behavior was shown. In contrast, in the low alloy steel, the Cu, Sb compounds accumulated on the surface improved the corrosion resistance by suppressing the anodic dissolution reaction.

  10. Deformation mechanism maps for pure iron, corrosion resistant austenitic steels and a low-alloy carbon steel

    International Nuclear Information System (INIS)

    Frost, H.Y.; Ashby, M.F.

    1980-01-01

    Principles of construction of deformation mechanisms charts for iron base alloys are presented. Deformation mechanisms charts for pure iron, 316 and 314 stainless steels, a ferritic steel with 1% Cr, Mo, V are given, examples of the charts application being provided. The charts construction is based, when it is possible, on the state equations, deduced from theoretical models and satisfying experimental data. The charts presented should be considered as an attempt to unite the main regularities of the theory of dislocations and diffusion with the observed experimental picture of plastic deformation and creep of commercial steels [ru

  11. Fatigue of carbon and low-alloy steels in LWR environments

    International Nuclear Information System (INIS)

    Chopra, O.K.; Michaud, W.F.; Shack, W.J.

    1994-01-01

    Fatigue tests have been conducted on A106-Gr B carbon steel and A533-Gr B low-alloy steel to evaluate the effects of an oxygenated-water environment on the fatigue life of these steels. For both steels, environmental effects are modest in PWR water at all strain rates. Fatigue data in oxygenated water confirm the strong dependence of fatigue life on dissolved oxygen (DO) and strain rate. The effect of strain rate on fatigue life saturates at some low value, e.g., between 0.0004 and 0.001%/s in oxygenated water with ∼0.8 ppm DO. The data suggest that the saturation value of strain rate may vary with DO and sulfur content of the steel. Although the cyclic stress-strain and cyclic-hardening behavior of carbon and low-alloy steels is distinctly different, the degradation of fatigue life of these two steels with comparable sulfur levels is similar. The carbon steel exhibits pronounced dynamic strain aging, whereas strain-aging effects are modest in the low-alloy steel. Environmental effects on nucleation of fatigue crack have also been investigated. The results suggest that the high-temperature oxygenated water has little or not effect on crack nucleation

  12. Features of Pd-Ni-Fe solder system for vacuum brazing of low alloy steels

    International Nuclear Information System (INIS)

    Radzievskij, V.N.; Kurochko, R.S.; Lotsmanov, S.N.; Rymar', V.I.

    1975-01-01

    The brazing solder of the Pd-Ni-Fe alloyed with copper and lithium, in order to decrease the melting point and provide for a better spreading, when soldered in vacuum ensures a uniform strength of soldered joints with the base metal of low-alloyed steels of 34KHNIM-type. The properties of low-alloyed steel joints brazed with the Pd-Ni-Fe-system solder little depend on the changes in the soldering parameters. The soldered joint keeps a homogeneous structure after all the stages of heat treatment (annealing, quenching and tempering)

  13. Charge transfer in chromium-transition metal alloys

    International Nuclear Information System (INIS)

    Kulakowski, K.; Maksymowicz, A.

    1984-07-01

    The average T-matrix approximation is applied for calculations of charge transfer of 3d-electrons in transition metal alloys. The role of concentration, long-range and short-range atomic order is investigated. The results are in reasonable agreement with experimental data. (author)

  14. Optimum alloy compositions in reduced-activation martensitic 9Cr steels for fusion reactor

    International Nuclear Information System (INIS)

    Abe, F.; Noda, T.; Okada, M.

    1992-01-01

    In order to obtain potential reduced-activation ferritic steels suitable for fusion reactor structures, the effect of alloying elements W and V on the microstructural evolution, toughness, high-temperature creep and irradiation hardening behavior was investigated for simple 9Cr-W and 9Cr-V steels. The creep strength of the 9Cr-W steels increased but their toughness decreased with increasing W concentration. The 9Cr-V steels exhibited poor creep rupture strength, far below that of a conventional 9Cr-1MoVNb steel and poor toughness after aging at 873 K. It was also found that the Δ-ferrite should be avoided, because it degraded both the roughness and high-temperature creep strength. Based on the results on the simple steels, optimized martensitic 9Cr steels were alloy-designed from a standpoint of enough thoughness and high-temperature creep strength. Two kinds of optimized 9Cr steels with low and high levels of W were obtained; 9Cr-1WVTa and 9Cr-3WVTa. These steels indeed exhibited excellent toughness and creep strength, respectively. The 9Cr-1WVTa steel exhibiting an excellent roughness was shown to be the most promising for relatively low-temperature application below 500deg C, where irradiation embrittlement is significant. The 9Cr-3WVTa steel was the most promising for high temperature application above 500deg C from the standpoint of enough high-temperature strength. (orig.)

  15. Deformation Induced Martensitic Transformation and Its Initial Microstructure Dependence in a High Alloyed Duplex Stainless Steel

    DEFF Research Database (Denmark)

    Xie, Lin; Huang, Tian Lin; Wang, Yu Hui

    2017-01-01

    Deformation induced martensitic transformation (DIMT) usually occurs in metastable austenitic stainless steels. Recent studies have shown that DIMT may occur in the austenite phase of low alloyed duplex stainless steels. The present study demonstrates that DIMT can also take place in a high alloyed...... Fe–23Cr–8.5Ni duplex stainless steel, which exhibits an unexpectedly rapid transformation from γ-austenite into α′-martensite. However, an inhibited martensitic transformation has been observed by varying the initial microstructure from a coarse alternating austenite and ferrite band structure...

  16. Evaluation of non-conformities of hip prostheses made of titanium alloys and stainless steel

    International Nuclear Information System (INIS)

    Bezerra, Ewerton de Oliveira Teotonio; Nascimento, Jose Jeferson da Silva; Luna, Carlos Bruno Barreto; Morais, Crislene Rodrigues da Silva; Campos, Karla Valeria Miranda de

    2017-01-01

    A large number of metallic alloys has satisfactory behavior when used to manufacture implants for hip prostheses. However, they must be in conformity with standards, to ensure their quality for long periods without losing its functionality. Therefore, this paper aims to study the non-conformities in two hip prostheses, one of titanium and other stainless steel according to standards. The implants studied passed by X-ray diffraction (XRD), X-ray fluorescence, tensile test and optical microscopy (OM). Specimens for the tensile test were made according to ASTM E 8M, as well, MO samples passed by metallographic procedure. The results evidenced that some chemical compositions showed in relation to the standards. The XRD analysis showed peaks of austenite and absence of ferrite for the stainless steel, while the titanium alloy presents an alpha phase (HCP) more significant than the beta phase (BCC). The stainless steel alloys and titanium have yield strength and tensile strength that meet the standards. On the other hand, the elastic modulus of the titanium alloy and stainless steel, comes to be ten times greater than the human bone. Therefore, the high modulus of elasticity of the alloys, favors bone resorption problems. The stainless steel microstructure is typical of an austenitic matrix, while the titanium alloy presents α + β microstructure. (author)

  17. Supercritical water corrosion of high Cr steels and Ni-base alloys

    International Nuclear Information System (INIS)

    Jang, Jin Sung; Han, Chang Hee; Hwang, Seong Sik

    2004-01-01

    High Cr steels (9 to 12% Cr) have been widely used for high temperature high pressure components in fossil power plants. Recently the concept of SCWR (supercritical water-cooled reactor) has aroused a keen interest as one of the next generation (Generation IV) reactors. Consequently Ni-base (or high Ni) alloys as well as high Cr steels that have already many experiences in the field are among the potential candidate alloys for the cladding or reactor internals. Tentative inlet and outlet temperatures of the anticipated SCWR are 280 and 510 .deg. C respectively. Among many candidate alloys there are austenitic stainless steels, Ni base alloys, ODS alloys as well as high Cr steels. In this study the corrosion behavior of the high Cr steels and Ni base (or high Ni) alloys in the supercritical water were investigated. The corrosion behavior of the unirradiated base metals could be used in the near future as a guideline for the out-of-pile or in-pile corrosion evaluation tests

  18. Effect of Cooling Rate on Microstructures and Mechanical Properties in SA508 Gr4N High Strength Low Alloy Steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Minchul; Park, Sanggyu; Choi, Kwonjae; Lee, Bongsang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The microstructure of Ni-Cr-Mo low alloy steel is a mixture of tempered martensite and tempered lower bainite and that of Mn-Mo-Ni low alloy steel is predominantly tempered upper bainite. Higher strength and toughness steels are very attractive as an eligible RPV steel, so several researchers have studied to use the Ni-Cr-Mo low alloy steel for the NPP application. Because of the thickness of reactor vessel, there are large differences in austenitizing cooling rates between the surface and the center locations of thickness in RPV. Because the cooling rates after austenitization determine the microstructure, it would affect the mechanical properties in Ni-Cr-Mo low alloy steel, and it may lead to inhomogeneous characteristics when the commercial scale of RPV is fabricated. In order to apply the Ni-Cr-Mo low alloy steel to RPV, it is necessary to evaluate the changes of microstructure and mechanical properties with varying phase fractions in Ni-Cr-Mo low alloy steel. In this study, the effects of martensite and bainite fractions on mechanical properties in Ni-Cr-Mo low alloy steel were examined by controlling the cooling rate after austenitization. First of all, continuous cooling transformation(CCT) diagram was established from the dilatometric analyses. Then, the phase fractions at each cooling rate were quantitatively evaluated. Finally, the mechanical properties were correlated with the phase fraction, especially fraction of martensite in Ni-Cr-Mo low alloy steel.

  19. The creep properties of a low alloy ferritic steel containing an intermetallic precipitate dispersion

    International Nuclear Information System (INIS)

    Batte, A.D.; Murphy, M.C.; Edmonds, D.V.

    1976-01-01

    A good combination of creep rupture ductility and strength together with excellent long term thermal stability, has been obtained from a dispersion of intermetallic Laves phase precipitate in a non-transforming ferritic low alloy steel. The steel is without many of the problems currently associated with the heat affected zone microstructures of low alloy transformable ferritic steels, and can be used as a weld metal. Following suitable development to optimize the composition and heat treatment, such alloys may provide a useful range of weldable creep resistant steels for steam turbine and other high temperature applications. They would offer the unique possibility of easily achievable microstructural uniformity, giving good long term strength and ductility across the entire welded joint

  20. Development of thermophysical calculator for stainless steel casting alloys by using CALPHAD approach

    Directory of Open Access Journals (Sweden)

    In-Sung Cho

    2017-11-01

    Full Text Available The calculation of thermophysical properties of stainless steel castings and its application to casting simulation is discussed. It is considered that accurate thermophysical properties of the casting alloys are necessary for the valid simulation of the casting processes. Although previous thermophysical calculation software requires a specific knowledge of thermodynamics, the calculation method proposed in the present study does not require any special knowledge of thermodynamics, but only the information of compositions of the alloy. The proposed calculator is based on the CALPHAD approach for modeling of multi-component alloys, especially in stainless steels. The calculator proposed in the present study can calculate thermophysical properties of eight-component systems on an iron base alloy (Fe-C-Si-Cr-Mn-Ni-Cu-Mo, and several Korean standard stainless steel alloys were calculated and discussed. The calculator can evaluate the thermophysical properties of the alloys such as density, heat capacity, enthalpy, latent heat, etc, based on full Gibbs energy for each phase. It is expected the proposed method can help casting experts to devise the casting design and its process easily in the field of not only stainless steels but also other alloy systems such as aluminum, copper, zinc, etc.

  1. Corrosion of carbon steel and low-alloy steel in diluted seawater containing hydrazine under gamma-rays irradiation

    International Nuclear Information System (INIS)

    Nakano, Junichi; Yamamoto, Masahiro; Tsukada, Takashi

    2014-01-01

    Seawater was injected into reactor cores of Units 1, 2, and 3 in the Fukushima Daiichi nuclear power station as an urgent coolant. It is considered that the injected seawater causes corrosion of steels of the reactor pressure vessel and primary containment vessel. To investigate the effects of gamma-rays irradiation on weight loss in carbon steel and low-alloy steel, corrosion tests were performed in diluted seawater at 50°C under gamma-rays irradiation. Specimens were irradiated with dose rates of 4.4 kGy/h and 0.2 kGy/h. To evaluate the effects of hydrazine (N 2 H 4 ) on the reduction of oxygen and hydrogen peroxide, N 2 H 4 was added to the diluted seawater. In the diluted seawater without N 2 H 4 , weight loss in the steels irradiated with 0.2 kGy/h was similar to that in the unirradiated steels, and weight loss in the steels irradiated with 4.4 kGy/h increased to approximate 1.7 times of those in the unirradiated steels. Weight loss in the steels irradiated in the diluted seawater containing N 2 H 4 was similar to that in the diluted seawater without N 2 H 4 . When N 2 was introduced into the gas phase in the flasks during gamma-rays irradiation, weight loss in the steels decreased. (author)

  2. Effect of Alloy 625 Buffer Layer on Hardfacing of Modified 9Cr-1Mo Steel Using Nickel Base Hardfacing Alloy

    Science.gov (United States)

    Chakraborty, Gopa; Das, C. R.; Albert, S. K.; Bhaduri, A. K.; Murugesan, S.; Dasgupta, Arup

    2016-04-01

    Dashpot piston, made up of modified 9Cr-1Mo steel, is a part of diverse safety rod used for safe shutdown of a nuclear reactor. This component was hardfaced using nickel base AWS ER NiCr-B alloy and extensive cracking was experienced during direct deposition of this alloy on dashpot piston. Cracking reduced considerably and the component was successfully hardfaced by application of Inconel 625 as buffer layer prior to hardface deposition. Hence, a separate study was undertaken to investigate the role of buffer layer in reducing the cracking and on the microstructure of the hardfaced deposit. Results indicate that in the direct deposition of hardfacing alloy on modified 9Cr-1Mo steel, both heat-affected zone (HAZ) formed and the deposit layer are hard making the thickness of the hard layer formed equal to combined thickness of both HAZ and deposit. This hard layer is unable to absorb thermal stresses resulting in the cracking of the deposit. By providing a buffer layer of Alloy 625 followed by a post-weld heat treatment, HAZ formed in the modified 9Cr-1Mo steel is effectively tempered, and HAZ formed during the subsequent deposition of the hardfacing alloy over the Alloy 625 buffer layer is almost completely confined to Alloy 625, which does not harden. This reduces the cracking susceptibility of the deposit. Further, unlike in the case of direct deposition on modified 9Cr-1Mo steel, dilution of the deposit by Ni-base buffer layer does not alter the hardness of the deposit and desired hardness on the deposit surface could be achieved even with lower thickness of the deposit. This gives an option for reducing the recommended thickness of the deposit, which can also reduce the risk of cracking.

  3. Three dimensional atom probe study of Ni-base alloy/low alloy steel dissimilar metal weld interfaces

    International Nuclear Information System (INIS)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun

    2012-01-01

    Three dimensional atom probe tomography (3D APT) is applied to characterize the dissimilar metal joint which was welded between the Ni-based alloy, Alloy 690 and the low alloy steel, A533 Gr. B, with Alloy 152 filler metal. While there is some difficulty in preparing the specimen for the analysis, the 3D APT has a truly quantitative analytical capability to characterize nanometer scale particles in metallic materials, thus its application to the microstructural analysis in multicomponent metallic materials provides critical information on the mechanism of nanoscale microstructural evolution. In this study, the procedure for 3D APT specimen preparation was established, and those for dissimilar metal weld interface were prepared near the fusion boundary by a focused ion beam. The result of the analysis in this study showed the precipitation of chromium carbides near the fusion boundary between A533 Gr. B and Alloy 152.

  4. Three dimensional atom probe study of Ni-base alloy/low alloy steel dissimilar metal weld interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2012-08-15

    Three dimensional atom probe tomography (3D APT) is applied to characterize the dissimilar metal joint which was welded between the Ni-based alloy, Alloy 690 and the low alloy steel, A533 Gr. B, with Alloy 152 filler metal. While there is some difficulty in preparing the specimen for the analysis, the 3D APT has a truly quantitative analytical capability to characterize nanometer scale particles in metallic materials, thus its application to the microstructural analysis in multicomponent metallic materials provides critical information on the mechanism of nanoscale microstructural evolution. In this study, the procedure for 3D APT specimen preparation was established, and those for dissimilar metal weld interface were prepared near the fusion boundary by a focused ion beam. The result of the analysis in this study showed the precipitation of chromium carbides near the fusion boundary between A533 Gr. B and Alloy 152.

  5. Surface segregation energies in transition-metal alloys

    DEFF Research Database (Denmark)

    Ruban, Andrei; Skriver, Hans Lomholt; Nørskov, Jens Kehlet

    1999-01-01

    We present a database of 24 x 24 surface segregation energies of single transition metal impurities in transition-metal hosts obtained by a Green's-function linear-muffin-tin-orbitals method in conjunction with the coherent potential and atomic sphere approximations including a multipole correction...... to the electrostatic potential and energy. We use the database to establish the major factors which govern surface segregation in transition metal alloys. We find that the calculated trends are well described by Friedel's rectangular state density model and that the few but significant deviations from the simple...

  6. Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests

    Science.gov (United States)

    Burns, F. A.; Dyke, R. A., Jr.

    1979-01-01

    The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

  7. Study of the Metallurgical Aspects of Steel Micro-Alloying by Titan

    Directory of Open Access Journals (Sweden)

    Kijac, J.

    2006-01-01

    Full Text Available The metal properties upgrading applying it’s alloying with the simultaneous limitation of the impurities represents a prospective possibility of the metallurgical production further development. The interaction of the alloying substance active element with oxygen in metal and adjacent multiphase environment occurs under the actual conditions. Present paper is oriented particularly to the thermodynamic aspects of deoxygenation by titan in process of production of micro alloyed low carbon steel in two plants (oxygen converter 1-OC1 and 2-OC2 with the different effect of micro-alloy exploitation. Analysis of the effect of the metallurgical factors on the titan smelting loss in micro-alloyed steel production points at the need to master the metal preparation for the alloying and especially has got the decisive effect upon the oxidizing ability and rate of the slag phase availability. When comparing the micro-alloying matter yield among the individual production units, disclosed have been better results obtained in plant OC 2. Confirmed has been the effect of the slag amount (average amount of 7,3 t at OC 1 and 5,83 t at OC 2 and its quality during the steel tapping as one among the most significant factors affecting the alloying process and which also represent its oxidizing potential.

  8. On the transition of short cracks into long fatigue cracks in reactor pressure vessel steels

    Directory of Open Access Journals (Sweden)

    Singh Rajwinder

    2018-01-01

    Full Text Available Short fatigue cracks, having dimension less than 1 mm, propagate at much faster rates (da/dN even at lower stress intensity factor range (da/dN as compared to the threshold stress intensity factor range obtained from long fatigue crack growth studies. These short cracks originate at the sub-grain level and some of them ultimately transit into critical long cracks over time. Therefore, designing the components subjected to fatigue loading merely on the long crack growth data and neglecting the short crack growth behavior can overestimate the component’s life. This aspect of short fatigue cracks become even more critical for materials used for safety critical applications such as reactor pressure vessel (RPV steel in nuclear plants. In this work, the transition behaviour of short fatigue crack gowth into long fatigue crack is studied in SA508 Grade 3 Class I low alloy steel used in RPVs. In-situ characterization of initiation, propagation and transition of short fatigue cracks is performed using fatigue stage for Scanning Electron Microscope (SEM in addition to digital microscopes fitted over a servo-hydraulic fatigue machine and correlated with the microtructural information obtained using electron backscatter diffraction (EBSD. SA508 steel having an upper bainitic microstructure have several microstructural interfaces such as phase and grain boundaries that play a significant role in controlling the short fatigue crack propagation. Specially designed and prepared short fatigue specimens (eletro-polished with varying initial crack lengths of the order of tens of microns are used in this study. The transition of such short initial cracks into long cracks is then tracked to give detailed insight into the role of each phase and phase/grain boundary with an objective of establishing Kitagawa-Takahashi diagram for the given RPV steel. The behavior of the transited long cracks is then compared with the crack propagation behavior obtained using

  9. Additional materials for welding of the EP99 heat resisting alloy with the EI868 alloy and 12Kh18N9T steel

    International Nuclear Information System (INIS)

    Sorokin, L.I.; Filippova, S.P.; Petrova, L.A.

    1978-01-01

    Presented are the results of the studies aimed at selecting an additive material for argon-arc welding process involving heat-resistant nickel EP99 alloy to be welded to the EI868 alloy and 12Kh18N9T steel. As the additive material use was made of wire made of nickel-chromium alloys and covered electrodes made of the EP367 alloy with additions of tungsten. It has been established that in order to improve the resistance of metal to hot-crack formation during argon arc welding of the EP99 alloy with the EI868 alloy, it is advisable to use an additive material of the EP533 alloy, and while welding the same alloy with the 12Kh18N9T steel, filler wire of the EP367 alloy is recommended

  10. Nickel-titanium alloys: stress-related temperature transitional range.

    Science.gov (United States)

    Santoro, M; Beshers, D N

    2000-12-01

    The inducement of mechanical stress within nickel-titanium wires can influence the transitional temperature range of the alloy and therefore the expression of the superelastic properties. An analogous variation of the transitional temperature range may be expected during orthodontic therapy, when the archwires are engaged into the brackets. To investigate this possibility, samples of currently used orthodontic nickel-titanium wires (Sentalloy, GAC; Copper Ni-Ti superelastic at 27 degrees C, 35 degrees C, 40 degrees C, Ormco; Nitinol Heat-Activated, 3M-Unitek) were subjected to temperature cycles ranging between 4 degrees C and 60 degrees C. The wires were mounted in a plexiglass loading device designed to simulate clinical situations of minimum and severe dental crowding. Electrical resistivity was used to monitor the phase transformations. The data were analyzed with paired t tests. The results confirmed the presence of displacements of the transitional temperature ranges toward higher temperatures when stress was induced. Because nickel-titanium wires are most commonly used during the aligning stage in cases of severe dental crowding, particular attention was given to the performance of the orthodontic wires under maximum loading. An alloy with a stress-related transitional temperature range corresponding to the fluctuations of the oral temperature should express superelastic properties more consistently than others. According to our results, Copper Ni-Ti 27 degrees C and Nitinol Heat-Activated wires may be considered suitable alloys for the alignment stage.

  11. Electrical and Magnetic Properties of Binary Amorphous Transition Metal Alloys.

    Science.gov (United States)

    Liou, Sy-Hwang

    The electrical, superconductive and magnetic properties of several binary transition metal amorphous and metastable crystalline alloys, Fe(,x)Ti(,100-x) (30 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Zr(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 93), Fe(,x)Hf(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 100), Fe(,x)Nb(,100 -x) (22 (LESSTHEQ) x (LESSTHEQ) 85), Ni(,x)Nb(,100-x) (20 (LESSTHEQ) x (LESSTHEQ) 80), Cu(,x)Nb(,100-x) (10 (LESSTHEQ) x (LESSTHEQ) 90) were studied over a wide composition range. Films were made using a magnetron sputtering system, and the structure of the films was investigated by energy dispersive x-ray diffraction. The composition region of each amorphous alloys system was determined and found in good agreement with a model proposed by Egami and Waseda. The magnetic properties and hyperfine interactions in the films were investigated using a conventional Mossbauer spectrometer and a ('57)Co in Rh matrix source. In all Fe-early transition metal binary alloys systems, Fe does not retain its moment in the low iron concentration region and the result is that the critical concentration for magnetic order (x(,c)) is much larger than anticipated from percolation considerations. A direct comparison between crystalline alloys and their amorphous counterparts of the same composition illustrate no clear correlation between crystalline and amorphous states. Pronounced discontinuities in the magnetic properties with variation in Fe content of all Fe-early transition metal alloys at phase boundaries separating amorphous and crystalline states have been observed. This is caused by the differences in the atomic arrangement and the electronic structure between crystalline and amorphous solids. The temperature dependence of resistivity, (rho)(T), of several binary amorphous alloys of Fe-TM (where TM = Ti, Zr, Hf, Nb etc.) has been studied from 2K to 300K. The Fe-poor (x x(,c)) samples have distinctive differences in (rho)(T) at low temperature (below 30K). All the magnetic samples

  12. Corrosion fatigue crack growth in clad low-alloy steels: Part 1, medium-sulfur forging steel

    International Nuclear Information System (INIS)

    James, L.A.; Poskie, T.J.; Auten, T.A.; Cullen, W.H.

    1996-01-01

    Corrosion fatigue crack propagation tests were conducted on a medium- sulfur ASTM A508-2 forging steel overlaid with weld-deposited Alloy EN82H cladding. The specimens featured semi-elliptical surface cracks penetrating approximately 6.3 mm of cladding into the underlying steel. The initial crack sizes were relatively large with surface lengths of 30.3--38.3 mm, and depths of 13.1--16.8 mm. The experiments were conducted in a quasi-stagnant low-oxygen (O 2 < 10 ppb) aqueous environment at 243 degrees C, under loading conditions (ΔK, R, and cyclic frequency) conductive to environmentally-assisted cracking (EAC) in higher-sulfur steels under quasi-stagnant conditions. Earlier experiments on unclad compact tension specimens of this heat of steel did not exhibit EAC, and the present experiments on semi-elliptical surface cracks penetrating cladding also did not exhibit EAC

  13. An Investigation of the Mechanical Properties of a Weldment of 7% Nickel Alloy Steels

    Directory of Open Access Journals (Sweden)

    Jeong Yeol Park

    2016-11-01

    Full Text Available During the last decade, the demand for natural gas has steadily increased for the prevention of environmental pollution. For this reason, many liquefied natural gas (LNG carriers have been manufactured. Since one of the most important issues in the design of LNG carriers is to guarantee structural safety, the use of low-temperature materials is increasing. Among commonly employed low-temperature materials, nickel steel has many benefits such as good strength and outstanding corrosion resistance. Accordingly, nickel steels are one of the most commonly used low-temperature steels for LNG storage tanks. However, the study of fracture toughness with various welding consumables of 7% nickel alloy steel is insufficient for ensuring the structural safety of LNG storage tanks. Therefore, the aim of this study was to evaluate fracture toughness of several different weldments for 7% nickel alloy steels. The weldment of 7% nickel alloy steel was fabricated by tungsten inert gas (TIG, flux cored arc welding (FCAW, and gas metal arc welding (GMAW. In order to assess the material performance of the weldments at low temperature, fracture toughness such as crack tip opening displacement (CTOD and the absorbed impact energy of weldments were compared with those of 9% nickel steel weldments.

  14. Heterogeneities in local plastic flow behavior in a dissimilar weld between low-alloy steel and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Mas, Fanny [Université Grenoble Alpes, SIMAP, 38000 Grenoble (France); CNRS, SIMAP, 38000 Grenoble (France); Martin, Guilhem, E-mail: guilhem.martin@simap.grenoble-inp.fr [Université Grenoble Alpes, SIMAP, 38000 Grenoble (France); CNRS, SIMAP, 38000 Grenoble (France); Lhuissier, Pierre; Bréchet, Yves; Tassin, Catherine [Université Grenoble Alpes, SIMAP, 38000 Grenoble (France); CNRS, SIMAP, 38000 Grenoble (France); Roch, François [Areva NP, Tour Areva, 92084 Paris La Défense (France); Todeschini, Patrick [EDF R& D, Avenue des Renardières, 77250 Moret-sur-Loing (France); Simar, Aude [Institute of Mechanics, Materials and Civil Engineering (iMMC), Université catholique de Louvain, 1348 Louvain-la-Neuve (Belgium)

    2016-06-14

    In dissimilar welds between low-alloy steel and stainless steel, the post-weld heat-treatment results in a high variety of microstructures coexisting around the fusion line, due to carbon diffusion and carbides dissolution/precipitation. The local constitutive laws in the vicinity of the fusion zone were identified by micro tensile specimens for the sub-millimeter sized zones, equivalent bulk materials representing the decarburized layer using both wet H{sub 2} atmosphere and diffusion couple, and nano-indentation for the carburized regions (i.e. the martensitic band and the austenitic region). The decarburized zone presents only 50% of the yield strength of the low-alloy steel heat affected zone and a ductility doubled. The carburized zones have a yield strength 3–5 times higher than that of the low-alloy steel heat affected zone and have almost no strain hardening capacity. These properties result in heterogeneous plastic deformation happening over only millimeters when the weld is loaded perpendicularly to the weld line, affecting its overall behavior. The constitutive laws experimentally identified were introduced as inputs into a finite elements model of the transverse tensile test performed on the whole dissimilar weld. A good agreement between experiments and simulations was achieved on the global stress-strain curve. The model also well predicts the local strain field measured by microscale DIC. A large out-of-plane deformation due to the hard carburized regions has also been identified.

  15. Structural models for amorphous transition metal binary alloys

    International Nuclear Information System (INIS)

    Ching, W.Y.; Lin, C.C.

    1976-01-01

    A dense random packing of 445 hard spheres with two different diameters in a concentration ratio of 3 : 1 was hand-built to simulate the structure of amorphous transition metal-metalloid alloys. By introducing appropriate pair potentials of the Lennard-Jones type, the structure is dynamically relaxed by minimizing the total energy. The radial distribution functions (RDF) for amorphous Fe 0 . 75 P 0 . 25 , Ni 0 . 75 P 0 . 25 , Co 0 . 75 P 0 . 25 are obtained and compared with the experimental data. The calculated RDF's are resolved into their partial components. The results indicate that such dynamically constructed models are capable of accounting for some subtle features in the RDF of amorphous transition metal-metalloid alloys

  16. 75 FR 44763 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico; Extension of Time Limit for Preliminary...

    Science.gov (United States)

    2010-07-29

    ...-Alloy Steel Pipe From Mexico; Extension of Time Limit for Preliminary Results of Antidumping Duty... review of the antidumping duty order on certain circular welded non- alloy steel pipe from Mexico. We... preliminary results of this review within the original time frame because we require additional time with...

  17. Characterization of Coatings on Steel Self-Piercing Rivets for Use with Magnesium Alloys

    Science.gov (United States)

    McCune, Robert C.; Forsmark, Joy H.; Upadhyay, Vinod; Battocchi, Dante

    Incorporation of magnesium alloys in self-pierce rivet (SPR) joints poses several unique challenges among which are the creation of spurious galvanic cells and aggravated corrosion of adjacent magnesium when coated steel rivets are employed. This work firstly reviews efforts on development of coatings to steel fasteners for the diminution of galvanic corrosion when used with magnesium alloys. Secondly, approaches, based on several electrochemical methods, for the measurement of the galvanic-limiting effect of a number of commercially-available coatings to hardened 10B37 steel self-piercing rivets inserted into alloy couples incorporating several grades of magnesium are reported. Electrochemical impedance spectroscopy (EIS), zero-resistance ammeter (ZRA), corrosion potential and potential-mapping visualization methods (e.g. scanning vibrating electrode technique — SVET) are illustrated for the several rivet coatings considered.

  18. Stress corrosion cracking studies on ferritic low alloy pressure vessel steel - water chemistry and modelling aspects

    International Nuclear Information System (INIS)

    Tipping, P.; Ineichen, U.; Cripps, R.

    1994-01-01

    The susceptibility of low alloy ferritic pressure vessel steels (A533-B type) to stress corrosion cracking (SCC) degradation has been examined using various BWR type coolant chemistries. Fatigue pre-cracked wedge-loaded double cantilever beams and also constantly loaded 25 mm thick compact tension specimens have shown classical SCC attack. The influence of parameters such as dissolved oxygen content, water impurity level and conductivity, material chemical composition (sulphur content) and stress intensity level are discussed. The relevance of SCC as a life-limiting degradation mechanism for low alloy ferritic nuclear power plant PV steel is examined. Some parameters, thought to be relevant for modelling SCC processes in low alloy steels in simulated BWR-type coolant, are discussed. 8 refs., 1 fig., 4 tabs

  19. Microstructural development of diffusion-brazed austenitic stainless steel to magnesium alloy using a nickel interlayer

    International Nuclear Information System (INIS)

    Elthalabawy, Waled M.; Khan, Tahir I.

    2010-01-01

    The differences in physical and metallurgical properties of stainless steels and magnesium alloys make them difficult to join using conventional fusion welding processes. Therefore, the diffusion brazing of 316L steel to magnesium alloy (AZ31) was performed using a double stage bonding process. To join these dissimilar alloys, the solid-state diffusion bonding of 316L steel to a Ni interlayer was carried out at 900 deg. C followed by diffusion brazing to AZ31 at 510 deg. C. Metallographic and compositional analyses show that a metallurgical bond was achieved with a shear strength of 54 MPa. However, during the diffusion brazing stage B 2 intermetallic compounds form within the joint and these intermetallics are pushed ahead of the solid/liquid interface during isothermal solidification of the joint. These intermetallics had a detrimental effect on joint strengths when the joint was held at the diffusion brazing temperature for longer than 20 min.

  20. Bonding evolution with sintering temperature in low alloyed steels with chromium

    Directory of Open Access Journals (Sweden)

    Fuentes-Pacheco L.

    2009-01-01

    Full Text Available At present, high performance PM steels for automotive applications follow a processing route that comprises die compaction of water-atomized powder, followed by sintering and secondary treatments, and finishing operations. This study examines Cr-alloyed sintered steels with two level of alloying. In chromium-alloyed steels, the surface oxide on the powder is of critical importance for developing the bonding between the particles during sintering. Reduction of this oxide depends mainly on three factors: temperature, dew point of the atmosphere, and carbothermic reduction provided by the added graphite. The transformation of the initial surface oxide evolves sequence as temperature increases during sintering, depending on the oxide composition. Carbothermic reduction is supposed to be the controlling mechanism, even when sintering in hydrogen-containing atmospheres. The effect of carbothermic reduction can be monitored by investigating the behavior of the specimens under tensile testing, and studying the resultant fracture surfaces.

  1. Corrosion resistance of stainless steels and high Ni-Cr alloys to acid fluoride wastes

    International Nuclear Information System (INIS)

    Smith, H.D.; Mackey, D.B.; Pool, K.H.; Schwenk, E.B.

    1992-04-01

    TRUEX processing of Hanford Site waste will utilize potentially corrosive acid fluoride processing solutions. Appropriate construction materials for such a processing facility need to be identified. Toward this objective, candidate stainless steels and high Ni-Cr alloys have been corrosion tested in simulated acid fluoride process solutions at 333K. The high Ni-Cr alloys exhibited corrosion rates as low as 0.14 mm/y in a solution with an HF activity of about 1.2 M, much lower than the 19 to 94 mm/y observed for austenitic stainless steels. At a lower HF activity (about 0.008 M), stainless steels display delayed passivation while high Ni-Cr alloys display essentially no reaction

  2. Interfacial Reaction Characteristics and Mechanical Properties of Welding-brazing Bonding Between AZ31B Magnesium Alloy and PRO500 Ultra-high Strength Steel

    Directory of Open Access Journals (Sweden)

    CHEN Jian-hua

    2017-11-01

    Full Text Available Experiments were carried out with TIG welding-brazing of AZ31B magnesium alloy to PRO500 steel using TIG arc as heat source. The interfacial reaction characteristics and mechanical properties of the welding-brazing bonding were investigated. The results show that an effective bonding is achieved between AZ31B magnesium alloy and PRO500 steel by using TIG welding-brazing method. Some spontaneous oxidation reactions result in the formation of a transition zone containing AlFe3 phase with rich oxide. The micro-hardness value of the interfacial transition zone is between that of the AZ31B and the PRO500. Temper softening zone appears due to the welding thermal cycle nearby the bonding position in the interface. A higher heat input makes an increase of the brittle phases and leads to an obvious decrease of the bonding strength.

  3. Magnetic properties of fcc Ni-based transition metal alloy

    Czech Academy of Sciences Publication Activity Database

    Kudrnovský, Josef; Drchal, Václav

    2009-01-01

    Roč. 100, č. 9 (2009), s. 1193-1196 ISSN 1862-5282 R&D Projects: GA MŠk OC 150; GA AV ČR IAA100100616 Institutional research plan: CEZ:AV0Z10100520 Keywords : transition metal alloys * Ni-based * pair exchange interactions * Curie temperatures * renormalized RPA Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.862, year: 2009

  4. Microstructural Evolution of Advanced Radiation-Resistant ODS Steel with Different Lengths of Mechanical Alloying Time

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon; Kim, Ga Eon; Kang, Suk Hoon; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling well occurred to 120dpa at high temperatures and this leads the decrease of the mechanical properties and dimensional stability. Compared to this, ferritic/ martensitic steel is a good solution because of excellent thermal conductivity and good swelling resistance. Unfortunately, the available temperature range of ferritic/martensitic steel is limited up to 650 .deg. C. ODS steel is the most promising structural material because of excellent creep and irradiation resistance by uniformly distributed nano-oxide particles with a high density which is extremely stable at the high temperature in ferritic/martensitic matrix. In this study, powder properties and microstructures of the ODS steel with different length of mechanical alloying time was investigated. The ODS steel milled 5h showed homogeneous grain structure with the highest hardness.

  5. Microstructural Evolution of Advanced Radiation-Resistant ODS Steel with Different Lengths of Mechanical Alloying Time

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Kim, Ga Eon; Kang, Suk Hoon; Kim, Tae Kyu

    2015-01-01

    Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling well occurred to 120dpa at high temperatures and this leads the decrease of the mechanical properties and dimensional stability. Compared to this, ferritic/ martensitic steel is a good solution because of excellent thermal conductivity and good swelling resistance. Unfortunately, the available temperature range of ferritic/martensitic steel is limited up to 650 .deg. C. ODS steel is the most promising structural material because of excellent creep and irradiation resistance by uniformly distributed nano-oxide particles with a high density which is extremely stable at the high temperature in ferritic/martensitic matrix. In this study, powder properties and microstructures of the ODS steel with different length of mechanical alloying time was investigated. The ODS steel milled 5h showed homogeneous grain structure with the highest hardness

  6. Corrosion of martensitic steels in flowing 17Li83Pb alloy

    International Nuclear Information System (INIS)

    Flament, T.; Fauvet, P.; Hocde, B.; Sannier, J.

    1988-01-01

    Corrosion of three martensitic steels - 1.4914, HT9 and T91 - in the presence of flowing 17Li83Pb is investigated in thermal convection loops Tulip entirely made of 1.4914 steel. Two 3000-hour tests were performed at maximal temperatures of respectively 450 and 475 0 C with a δT of 60 0 C and an alloy velocity of about 0.08 m.s -1 . In both tests, corrosion is characterized by an homogeneous dissolution of the steel without formation of a corrosion layer. Corrosion rate is constant and very temperature dependent: the sound-metal loss of 1.4914 steel is 22 μm. year -1 at 450 0 C and 40 μm.year -1 at 475 0 C. Behaviours of 1.4914 and HT9 steels are very similar whereas T91 steel is about 20% less corroded

  7. Characterization of oxide scales grown on alloy 310S stainless steel after long term exposure to supercritical water at 500 °C

    Energy Technology Data Exchange (ETDEWEB)

    Behnamian, Yashar, E-mail: behnamia@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9 (Canada); Mostafaei, Amir [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Kohandehghan, Alireza [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9 (Canada); Amirkhiz, Babak Shalchi [Canmet MATERIALS, Natural Resources Canada, Hamilton, Ontario L8P 0A5 (Canada); Serate, Daniel [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9 (Canada); Zheng, Wenyue [Canmet MATERIALS, Natural Resources Canada, Hamilton, Ontario L8P 0A5 (Canada); Guzonas, David [Canadian Nuclear Laboratories, Chalk River Laboratories, Chalk River, Ontario K0J 1J0 (Canada); Chmielus, Markus [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Chen, Weixing, E-mail: Weixing@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9 (Canada); Luo, Jing Li, E-mail: Jingli.luo@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9 (Canada)

    2016-10-15

    The oxide scale grown of static capsules made of alloy 310S stainless steel was investigated by exposure to the supercritical water at 500 °C 25 MPa for various exposure times up to 20,000 h. Characterization techniques such as X-ray diffraction, scanning/transmission electron microscopy, energy dispersive spectroscopy, and fast Fourier transformation were employed on the oxide scales. The elemental and phase analyses indicated that long term exposure to the SCW resulted in the formation of scales identified as Fe{sub 3}O{sub 4} (outer layer), Fe-Cr spinel (inner layer), Cr{sub 2}O{sub 3} (transition layer) on the substrate, and Ni-enrichment (chrome depleted region) in the alloy 310S. It was found that the layer thickness and weight gain vs. exposure time followed parabolic law. The oxidation mechanism and scales grown on the alloy 310S stainless steel exposed to SCW are discussed. - Highlights: •Oxidation of alloy 310S stainless steel exposed to SCW (500 °C/25 MPa) •The layer thickness and weight gain vs. exposure time followed parabolic law. •Oxide layers including Fe{sub 3}O{sub 4} (outer), Fe-Cr spinel (inner) and Cr{sub 2}O{sub 3} (transition) •Ni element is segregated by the selective oxidation of Cr.

  8. Austenitic stainless steel alloys with high nickel contents in high temperature liquid metal systems

    International Nuclear Information System (INIS)

    Konvicka, H.R.; Schwarz, N.F.

    1981-01-01

    Fe-Cr-Ni base alloys (nickel content: from 15 to 70 wt%, Chromium content: 15 wt%, iron: balance) together with stainless steel (W.Nr. 1.4981) have been exposed to flowing liquid sodium at 730 0 C in four intervals up to a cumulative exposure time of 1500 hours. Weight change data and the results of post-exposition microcharacterization of specimens are reported. The corrosion rates increase with increasing nickel content and tend to become constant after longer exposure times for each alloy. The corrosion rate of stainless steel is considerably reduced due to the presence of the base alloys. Different kinetics of nickel poor (up to 35% nickel) and nickel rich (> 50% nickel) alloys and nickel transport from nickel rich to nickel poor material is observed. (orig.)

  9. Microstructure and properties of powder metallurgy (PM) high alloy tool steels

    International Nuclear Information System (INIS)

    Wojcieszynski, A.L.; Eisen, W.B.; Dixon, R.B.

    1998-01-01

    Particle metallurgy (PM) processing is currently the primary manufacturing method used to produce advanced high alloy tool steel compositions for use in industrial tooling applications. This process involves gas atomization of the pre-alloyed melt to form spherical powders and consolidation by HIP to full density. The HIP product may be used directly in select applications, but is usually subjected to additional forging to improve properties and produce a wide range of bar and plate sizes. Compared to ingot-cast tool steels, PM tool steels have very homogeneous microstructures with very fine carbide and sulfide size distributions, free from carbide banding, which results in improved machinability, grindability, and mechanical properties. In addition, this technology enables the development of advanced tool steel compositions which could not be economically produced by conventional steelmaking. (author)

  10. Load carrying capacity of RCC beams by replacing steel reinforcement bars with shape memory alloy bars

    Science.gov (United States)

    Bajoria, Kamal M.; Kaduskar, Shreya S.

    2016-04-01

    In this paper the structural behavior of reinforced concrete (RC) beams with smart rebars under two point loading system has been numerically studied, using Finite Element Method. The material used in this study is Super-elastic Shape Memory Alloys (SE SMAs) which contains nickel and titanium. In this study, different quantities of steel and SMA rebars have been used for reinforcement and the behavior of these models under two point bending loading system is studied. A comparison of load carrying capacity for the model between steel reinforced concrete beam and the beam reinforced with S.M.A and steel are performed. The results show that RC beams reinforced with combination of shape memory alloy and steel show better performance.

  11. 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.

  12. Enhanced Densification of PM Steels by Liquid Phase Sintering with Boron-Containing Master Alloy

    Science.gov (United States)

    Vattur Sundaram, Maheswaran; Surreddi, Kumar Babu; Hryha, Eduard; Veiga, Angela; Berg, Sigurd; Castro, Fransisco; Nyborg, Lars

    2018-01-01

    Reaching high density in PM steels is important for high-performance applications. In this study, liquid phase sintering of PM steels by adding gas-atomized Ni-Mn-B master alloy was investigated for enhancing the density levels of Fe- and Mo- prealloyed steel powder compacts. The results indicated that liquid formation occurs in two stages, beginning with the master alloy melting (LP-1) below and eutectic phase formation (LP-2) above 1373 K (1100 °C). Mo and C addition revealed a significant influence on the LP-2 temperatures and hence on the final densification behavior and mechanical properties. Microstructural embrittlement occurs with the formation of continuous boride networks along the grain boundaries, and its severity increases with carbon addition, especially for 2.5 wt pct of master alloy content. Sintering behavior, along with liquid generation, microstructural characteristics, and mechanical testing revealed that the reduced master alloy content from 2.5 to 1.5 wt pct (reaching overall boron content from 0.2 to 0.12 wt pct) was necessary for obtaining good ductility with better mechanical properties. Sintering with Ni-Mn-B master alloy enables the sintering activation by liquid phase formation in two stages to attain high density in PM steels suitable for high-performance applications.

  13. Irradiation enhanced diffusion and irradiation creep tests in stainless steel alloys

    International Nuclear Information System (INIS)

    Loelgen, R.H.; Cundy, M.R.; Schuele, W.

    1977-01-01

    A review is given of investigations on the rate of phase changes during neutron and electron irradiation in many different fcc alloys showing either precipitation or ordering. The diffusion rate was determined as a function of the irradiation flux, the irradiation temperature and the irradiation dose. It was found that the radiation enhanced diffusion in all the investigated alloys is nearly temperature independent and linearly dependent on the flux. From these results conclusions were drawn concerning the properties of point defects and diffusion mechanisms rate determining during irradiation, which appears to be of a common nature for fcc alloys having a similar structure to those investigated. It has been recognized that the same dependencies which are found for the diffusion rate were also observed for the irradiation creep rate in stainless steels, as reported in literature. On the basis of this obervation a combination of measurements is suggested, of radiation enhanced diffusion and radiation enhanced creep in stainless steel alloys. Measurements of radiation enhanced diffusion are less time consuming and expensive than irradiation creep tests and information on this property can be obtained rather quickly, prior to the selection of stainless steel alloys for creep tests. In order to investigate irradiation creep on many samples at a time two special rigs were developed which are distinguished only by the mode of stress applied to the steel specimens. Finally, a few uniaxial tensile creep tests will be performed in fully instrumented rigs. (Auth.)

  14. Selective surface oxidation and segregation upon short term annealing of model alloys and industrial steel grades

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, S.

    2007-07-01

    Segregation and selective oxidation phenomena of minor alloying elements during annealing of steel sheets lead to the formation of bare spots after hot-dip galvanizing. This thesis highlights the influence of annealing conditions and the effect of alloying elements on the selective oxidation in model alloys and some industrial steel grades. Model alloys of binary (Fe-2Si, Fe-2Mn, Fe-0.8Cr), ternary (Fe-2Mn-2Si, Fe-2Mn-0.8Cr, Fe-1Mn-0.8Cr, Fe-1Si-0.8Cr, Fe-2Si-0.8Cr) and quarternary (Fe-2Mn-2Si-0.8Cr) systems were studied. In the case of steels, standard grade interstitial free (IF) steels and experimental grade tensile strength 1000 MPa steel were investigated. All specimens were annealed at 820 C in N{sub 2}-5%H{sub 2} gas atmospheres with the wide range of dew points (i.e. -80 to 0 C). The surface chemistry after annealing and its wettability with liquid Zn have been correlated as a function of dew points by simulating the hot-dip galvanizing process at laboratory scale. (orig.)

  15. Comparison of stainless steel and titanium alloy orthodontic miniscrew implants: a mechanical and histologic analysis.

    Science.gov (United States)

    Brown, Ryan N; Sexton, Brent E; Gabriel Chu, Tien-Min; Katona, Thomas R; Stewart, Kelton T; Kyung, Hee-Moon; Liu, Sean Shih-Yao

    2014-04-01

    The detailed mechanical and histologic properties of stainless steel miniscrew implants used for temporary orthodontic anchorage have not been assessed. Thus, the purpose of this study was to compare them with identically sized titanium alloy miniscrew implants. Forty-eight stainless steel and 48 titanium alloy miniscrew implants were inserted into the tibias of 12 rabbits. Insertion torque and primary stability were recorded. One hundred grams of tensile force was applied between half of the implants in each group, resulting in 4 subgroups of 24 specimens each. Fluorochrome labeling was administered at weeks 4 and 5. When the rabbits were euthanized at 6 weeks, stability and removal torque were measured in half (ie, 12 specimens) of each of the 4 subgroups. Microdamage burden and bone-to-implant contact ratio were quantified in the other 12 specimens in each subgroup. Mixed model analysis of variance was used for statistical analysis. All implants were stable at insertion and after 6 weeks. The only significant difference was the higher (9%) insertion torque for stainless steel. No significant differences were found between stainless steel and titanium alloy miniscrew implants in microdamage burden and bone-to-implant contact regardless of loading status. Stainless steel and titanium alloy miniscrew implants provide the same mechanical stability and similar histologic responses, suggesting that both are suitable for immediate orthodontic clinical loads. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  16. Laser surface alloying of 316L stainless steel with Ru and Ni mixtures

    CSIR Research Space (South Africa)

    Lekala, MB

    2012-05-01

    Full Text Available an economically sound approach of modifying corrosion properties of alloys. Furthermore, since corrosion is a surface phenomenon, an equally cost-effective approach is to add these only on the surface, where protection is most required. Laser surface... powders were preplaced on the steel surface using a chemical binder. The thickness of the preplaced powder coatings could be controlled to approxi- mately 1mm. The laser surface alloying was performed with a Rofin Sinar DY044 continuous wave Nd : YAG...

  17. Electrochemical assessment of some titanium and stainless steel impact dental alloys

    International Nuclear Information System (INIS)

    Echavarria, A.; Arroyave, C.

    2003-01-01

    Commercially pure titanium alloy, Ti-6Al-4V alloy and stainless steel screw implants were evaluated in both Ringer and synthetic saliva physiological solutions at body temperature by EIS (Electrochemical Impedance Spectroscopy) with immersion times of 30 d. Results were simulated as a sandwich system composed by four capacitors-resistances connected in series with the solution resistance. A model explaining the results in terms of the porosity and thickness of four different layers, was proposed. (Author) 22 refs

  18. Micro alloyed steel weldability and sensibility testing on the lamellar cracks appearance

    Directory of Open Access Journals (Sweden)

    S. Stojadinović

    2011-07-01

    Full Text Available In this work are given the testing results of mechanical properties welded joints and microstructure of micro alloyed steel as well as its sensitivity to lamellar cracks appearance. The obtained results show that steel has good resistance to lamellar cracks appearance and with an appropriate wire choice for welding, a good combination of mechanical properties could be obtained at room (ambience temperatures as well as at low temperatures.

  19. Effect of operational conditions of electroerosion machining on the surface microgeometry parameters of steels and alloys

    International Nuclear Information System (INIS)

    Foteev, N.K.

    1976-01-01

    Studies the influence of pulse duration and a series of operating conditions of a ShGI-40-440 spark-machining generator on changes in the basic surface microgeometry characteristics of components of stainless steel 1Kh18N10T, steel St 45 and hard alloy T14K8. The microgeometry characteristics of spark-machined surfaces differ significantly from the corresponding characteristics of surfaces machined by cutting and vibro-rolling

  20. Technological Aspects of Low-Alloyed Cast Steel Massive Casting Manufacturing

    Directory of Open Access Journals (Sweden)

    Szajnara J.

    2013-12-01

    Full Text Available In the paper authors have undertaken the attempt of explaining the causes of cracks net occurrence on a massive 3-ton cast steel casting with complex geometry. Material used for casting manufacturing was the low-alloyed cast steel with increased wear resistance modified with vanadium and titanium. The studies included the primary and secondary crystallization analysis with use of TDA and the qualitative and quantitative analysis of non-metallic inclusions.

  1. Galvannealing of (high-)manganese-alloyed TRIP- and X-IP registered -steel

    Energy Technology Data Exchange (ETDEWEB)

    Blumenau, M. [ThyssenKrupp Steel Europe AG, Bamenohler Strasse 211, D-57402 Finnentrop (Germany); Norden, M. [DOC Dortmunder Oberflaechencentrum GmbH, Eberhardstrasse 12, D-44145 Dortmund (Germany); Friedel, F.; Peters, K. [ThyssenKrupp Steel Europe AG, Kaiser-Wilhelm-Strasse 100, D-47166 Duisburg (Germany)

    2010-12-15

    In this study the influence of Mn on galvannealed coatings of 1.7% Mn-1.5% Al TRIP- and 23% Mn X-IP registered -steels was investigated. It is shown that the external selective oxides like Mn, Al and Si of the TRIP steel which occur after annealing at 800 C for 60 s at a dew point (DP) of -25 C (5% H{sub 2}) hamper the Fe/Zn-reaction during subsequent galvannealing. Preoxidation was beneficially utilized to increase the surface-reactivity of the TRIP steel under the same dew point conditions. The influence of Mn on the steel alloy was investigated by using a 23% Mn containing X-IP registered -steel which was bright annealed at 1100 C for 60 s at DP -50 C (5% H{sub 2}) to obtain a mainly oxide free surface prior to hot dip galvanizing (hdg) and subsequent galvannealing. As well known from the literature Mn alloyed to the liquid zinc melt stabilizes {delta}-phase at lower temperatures by participating in the Fe-Zn-phase reactions, it was expected that the metallic Mn of the X-IP registered -steel increases the Fe/Zn-reactivity in the same manner. The approximation of the effective diffusion coefficient (D{sub eff}(Fe)) during galvannealing was found to be higher than compared to a low alloyed steel reference. Contrary to the expectation no increased Fe/Zn-reaction was found by microscopic investigations. Residual {eta}- and {zeta}-phase fractions prove a hampered Fe/Zn-reaction. As explanation for the observed hampered Fe/Zn-reaction the lower Fe-content of the high-Mn-alloyed X-IP registered -steel was suggested as the dominating factor for galvannealing. (Copyright copyright 2010 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Special Features of Induction Annealing of Friction Stir Welded Joints of Medium-Alloy Steels

    Science.gov (United States)

    Priymak, E. Yu.; Stepanchukova, A. V.; Bashirova, E. V.; Fot, A. P.; Firsova, N. V.

    2018-01-01

    Welded joints of medium-alloy steels XJY750 and 40KhN2MA are studied in the initial condition and after different variants of annealing. Special features of the phase transformations occurring in the welded steels are determined. Optimum modes of annealing are recommended for the studied welded joints of drill pipes, which provide a high level of mechanical properties including the case of impact loading.

  3. Studies of iodine concentration in steel and transition metals

    International Nuclear Information System (INIS)

    Kormann, C.; Kozlowski, W.; Oleksi-Frenzel, J.; Nachtigall, K.; Neste, A. van; Welsh, M.; Titze-Zaeske, B.; Plieth, W.

    1990-01-01

    Radioactive iodine which originates from nuclear fuel reprocessing plants as a fission product and consists mainly of the radioactive isotopes 129 I, 131 I, and of the inactive 127 I, must be quantitatively adsorbed at the end of the process for the purpose of safe waste disposal. Inspite of using high-alloy austenitic chrome nickel steels, major corrosion effects were observed at tubes and containers of the PASSAT dissolver waste gas purifier. This research project serves to clarify the question in which parts of the installation iodine concentration is to be expected under certain conditions. Furthermore it serves to identify the redox state of iodine in the various installation components. For this purpose steel (1.4306esu and 1.4563N), zirconium and titanium were studied in nitric iodic media. With the objective of calculating iodine adsorption isotherms, the following methods were used to obtain qualitative and quantitative data: FTIR, ellipsometry, 131 I radiotracer method, cyclo-voltametry, closed circuit potential measurements, ion chromatography. (orig./DG) [de

  4. Parameters of Models of Structural Transformations in Alloy Steel Under Welding Thermal Cycle

    Science.gov (United States)

    Kurkin, A. S.; Makarov, E. L.; Kurkin, A. B.; Rubtsov, D. E.; Rubtsov, M. E.

    2017-05-01

    A mathematical model of structural transformations in an alloy steel under the thermal cycle of multipass welding is suggested for computer implementation. The minimum necessary set of parameters for describing the transformations under heating and cooling is determined. Ferritic-pearlitic, bainitic and martensitic transformations under cooling of a steel are considered. A method for deriving the necessary temperature and time parameters of the model from the chemical composition of the steel is described. Published data are used to derive regression models of the temperature ranges and parameters of transformation kinetics in alloy steels. It is shown that the disadvantages of the active visual methods of analysis of the final phase composition of steels are responsible for inaccuracy and mismatch of published data. The hardness of a specimen, which correlates with some other mechanical properties of the material, is chosen as the most objective and reproducible criterion of the final phase composition. The models developed are checked by a comparative analysis of computational results and experimental data on the hardness of 140 alloy steels after cooling at various rates.

  5. Study of the distribution of alloying elements between the phases of a heat treated steel

    International Nuclear Information System (INIS)

    Lambert, N.; Greday, T.

    1977-01-01

    The behavior of some low-alloy steels during industrial heat treatments is systematically studied. Firstly, the influence of the chemical analysis of the steel, the shape and size of carbides on the kinetics of the dissolution of these carbides at high temperature is pointed out in the case of steels with a relatively simple chemical analysis. Secondly, the effect of tempering treatments on the mechanical properties and characteristic parameters of the microstructure is studied in the case of three low-alloy steels. Bainitic microstructure appears to be the less disturbed one after a tempering treatment. Against, martensitic microstructures undergo an important softening and the mechanical properties of the pearlite lie as a very low level whatever their heat treatment. Peculiar conditions of tempering promotes a fine precipitation and its combined secondary hardening. These conditions are related to both chemical analysis and initial microstructure of the steel. Besides, some chemical identifications were performed in the scanning electron microscope on alloyed carbides precipitated in the steel during very long time tempering treatments

  6. Oxide nanoparticles in an Al-alloyed oxide dispersion strengthened steel: crystallographic structure and interface with ferrite matrix

    DEFF Research Database (Denmark)

    Zhang, Zhenbo; Pantleon, Wolfgang

    2017-01-01

    Oxide nanoparticles are quintessential for ensuring the extraordinary properties of oxide dispersion strengthened (ODS) steels. In this study, the crystallographic structure of oxide nanoparticles, and their interface with the ferritic steel matrix in an Al-alloyed ODS steel, i.e. PM2000, were...

  7. Study on Spheroidization and Related Heat Treatments of Medium Carbon Alloy Steels

    Directory of Open Access Journals (Sweden)

    Harisha S. R.

    2018-01-01

    Full Text Available The importance of medium carbon steels as engineering materials is reflected by the fact that out of the vast majority of engineering grade ferrous alloys available and used in the market today, a large proportion of them are from the family of medium carbon steels. Typically medium carbon steels have a carbon range of 0.25 to 0.65% by weight, and a manganese content ranging from 0.060 to 1.65% by weight. Medium carbon steels are more resistive to cutting, welding and forming as compared to low carbon steels. From the last two decades a number of research scholars reported the use of verity of heat treatments to tailor the properties of medium carbon steels. Spheroidizing is the novel industrial heat treatment employed to improve formability and machinability of medium/high carbon low alloy steels. This exclusive study covers procedure, the effects and possible outcomes of various heat treatments on medium carbon steels. In the present work, other related heat treatments like annealing and special treatments for property alterations which serve as pretreatments for spheroidizing are also reviewed. Medium carbon steels with property alterations by various heat treatment processes are finding increased responsiveness in transportation, aerospace, space, underwater along with other variegated fields. Improved tribological and mechanical properties consisting of impact resistance, stiffness, abrasion and strength are the main reasons for the increased attention of these steels in various industries. In the present scenario for the consolidation of important aspects of various heat treatments and effects on mechanical properties of medium carbons steel, a review of different research papers has been attempted. This review may be used as a guide to provide practical data for heat treatment industry, especially as a tool to enhance workability and tool life.

  8. Medium carbon vanadium micro alloyed steels for drop forging

    International Nuclear Information System (INIS)

    Jeszensky, Gabor; Plaut, Ronald Lesley

    1992-01-01

    Growing competitiveness of alternative manufacturing routes requires cost minimization in the production of drop forged components. The authors analyse the potential of medium carbon, vanadium microalloyed steels for drop forging. Laboratory and industrial experiments have been carried out emphasizing deformation and temperature cycles, strain rates and dwell times showing a typical processing path, associated mechanical properties and corresponding microstructures. The steels the required levels of mechanical properties on cooling after forging, eliminating subsequent heat treatment. The machinability of V-microalloyed steels is also improved when compared with plain medium carbon steels. (author)

  9. A detailed investigation of the strain hardening response of aluminum alloyed Hadfield steel

    Science.gov (United States)

    Canadinc, Demircan

    The unusual strain hardening response exhibited by Hadfield steel single and polycrystals under tensile loading was investigated. Hadfield steel, which deforms plastically through the competing mechanisms slip and twinning, was alloyed with aluminum in order to suppress twinning and study the role of slip only. To avoid complications due to a grained structure, only single crystals of the aluminum alloyed Hadfield steel were considered at the initial stage of the current study. As a result of alloying with aluminum, twinning was suppressed; however a significant increase in the strain hardening response was also present. A detailed microstructural analysis showed the presence of high-density dislocation walls that evolve in volume fraction due to plastic deformation and interaction with slip systems. The very high strain hardening rates exhibited by the aluminum alloyed Hadfield steel single crystals was attributed to the blockage of glide dislocations by the high-density dislocation walls. A crystal plasticity model was proposed, that accounts for the volume fraction evolution and rotation of the dense dislocation walls, as well as their interaction with the active slip systems. The novelty of the model lies in the simplicity of the constitutive equations that define the strain hardening, and the fact that it is based on experimental data regarding the microstructure. The success of the model was tested by its application to different crystallographic orientations, and finally the polycrystals of the aluminum alloyed Hadfield steel. Meanwhile, the capability of the model to predict texture was also observed through the rotation of the loading axis in single crystals. The ability of the model to capture the polycrystalline deformation response provides a venue for its utilization in other alloys that exhibit dislocation sheet structures.

  10. Alloying element effect on the mechanical properties of high-strength stainless steels and welds

    International Nuclear Information System (INIS)

    Pustovit, A.I.; Yushchenko, K.A.; Fortunatova, N.N.

    1977-01-01

    Experimental steels containing 11-17% Cr, 3-13% Ni, 0-2% Mo, 0-1% Ti, 1-2% Cu, 0-4% Co, 0-1% He, < 0.03% C and their welded joints have been studied. The ''MRA-1'' program was used to obtain mathematical description (in the form of regression equations) of the effect of alloying elements on strength and plasticity of the steels and the welded joints at 20...-196 deg C. The dependences obtained make it possible to predict the properties of the steels and the joints in a satisfactory agreement with their actual behaviour at 20...-196 deg C

  11. Effects of LWR environments on fatigue life of carbon and low-alloy steels

    International Nuclear Information System (INIS)

    Chopra, O.K.; Shack, W.J.

    1995-03-01

    SME Boiler and Pressure Vessel Code provides construction of nuclear power plant components. Figure I-90 Appendix I to Section III of the Code specifies fatigue design curves for structural materials. While effects of environments are not explicitly addressed by the design curves, test data suggest that the Code fatigue curves may not always be adequate in coolant environments. This paper reports the results of recent fatigue tests that examine the effects of steel type, strain rate, dissolved oxygen level, strain range, loading waveform, and surface morphology on the fatigue life of A 106-Gr B carbon steel and A533-Gr B low-alloy steel in water

  12. Interim fatigue design curves for carbon, low-alloy, and austenitic stainless steels in LWR environments

    International Nuclear Information System (INIS)

    Majumdar, S.; Chopra, O.K.; Shack, W.J.

    1993-01-01

    Both temperature and oxygen affect fatigue life; at the very low dissolved-oxygen levels in PWRs and BWRs with hydrogen water chemistry, environmental effects on fatigue life are modest at all temperatures (T) and strain rates. Between 0.1 and 0.2 ppM, the effect of dissolved-oxygen increases rapidly. In oxygenated environments, fatigue life depends strongly on strain rate and T. A fracture mechanics model is developed for predicting fatigue lives, and interim environmentally assisted cracking (EAC)-adjusted fatigue curves are proposed for carbon steels, low-alloy steels, and austenitic stainless steels

  13. Influence of microstructure of high-strength low-alloy steels on their weldability

    International Nuclear Information System (INIS)

    Cwiek, J.; Labanowski, J.

    2003-01-01

    Microstructure of steel before welding has influence on the steel's susceptibility to cold cracking because it influences hardenability and maximum hardness of heat affected zone (HAZ). Two high-strength low-alloy (HSLA) steel grades 18G2AV and 14HNMBCu, in various heat treatment conditions, were subjected to simulated welding thermal cycles. It was revealed that maximum HAZ hardness is influenced by microstructure presented before thermal cycle was applied. The higher HAZ hardness was observed for quenched and tempered condition, comparing to full annealed and overheated conditions. (author)

  14. Corrosion of steels in molten gallium (Ga), tin (Sn) and tin lithium alloy (Sn–20Li)

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Masatoshi, E-mail: kondo.masatoshi@nr.titech.ac.jp [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Ishii, Masaomi [Department of Nuclear Engineering, School of Engineering, Tokai University, 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Muroga, Takeo [Department of Helical Plasma Research, National Institute for Fusion Science, Toki, Gifu 502-5292 (Japan)

    2015-10-15

    Graphical abstract: Corrosion of RAFM steel, JLF-1, in liquid Sn–20Li was caused by the formation of Fe-Sn alloyed layer. - Highlights: • The corrosion tests were performed for the reduced activation ferritic martensitic steel JLF-1 and the austenitic steel SUS316 in liquid Ga, Sn and Sn-20Li at 873 K up to 750 h. • The weight loss of the specimens exposed to liquid Ga, Sn and Sn-20Li was evaluated. • The corrosion of the steels in liquid Ga was caused by the alloying reaction between Ga and Fe on the steel surface. • The corrosion of the steels in liquid Sn was caused by the alloying reaction between Sn and Fe on the steel surface. • The corrosion of the steels in liquid Sn-20Li was caused by the formation of the Fe-Sn alloyed layer and the diffusion of Sn and Li into the steel matrix. - Abstract: The compatibility of steels in liquid gallium (Ga), tin (Sn) and tin lithium alloy (Sn–20Li) was investigated by means of static corrosion tests. The corrosion tests were performed for reduced activation ferritic martensitic steel JLF-1 (JOYO-HEAT, Fe–9Cr–2W–0.1C) and austenitic steel SUS316 (Fe–18Cr–12Ni–2Mo). The test temperature was 873 K, and the exposure time was 250 and 750 h. The corrosion of these steels in liquid Ga, Sn and Sn–20Li alloy was commonly caused by the formation of a reaction layer and the dissolution of the steel elements into the melts. The reaction layer formed in liquid Ga was identified as Fe{sub 3}Ga from the results of metallurgical analysis and the phase diagram. The growth rate of the reaction layer on the JLF-1 steel showed a parabolic rate law, and this trend indicated that the corrosion could be controlled by the diffusion process through the layer. The reaction layer formed in liquid Sn and Sn–20Li was identified as FeSn. The growth rate had a linear function with exposure time. The corrosion in Sn and Sn–20Li could be controlled by the interface reaction on the layer. The growth rate of the layer formed

  15. Corrosion of steels in molten gallium (Ga), tin (Sn) and tin lithium alloy (Sn–20Li)

    International Nuclear Information System (INIS)

    Kondo, Masatoshi; Ishii, Masaomi; Muroga, Takeo

    2015-01-01

    Graphical abstract: Corrosion of RAFM steel, JLF-1, in liquid Sn–20Li was caused by the formation of Fe-Sn alloyed layer. - Highlights: • The corrosion tests were performed for the reduced activation ferritic martensitic steel JLF-1 and the austenitic steel SUS316 in liquid Ga, Sn and Sn-20Li at 873 K up to 750 h. • The weight loss of the specimens exposed to liquid Ga, Sn and Sn-20Li was evaluated. • The corrosion of the steels in liquid Ga was caused by the alloying reaction between Ga and Fe on the steel surface. • The corrosion of the steels in liquid Sn was caused by the alloying reaction between Sn and Fe on the steel surface. • The corrosion of the steels in liquid Sn-20Li was caused by the formation of the Fe-Sn alloyed layer and the diffusion of Sn and Li into the steel matrix. - Abstract: The compatibility of steels in liquid gallium (Ga), tin (Sn) and tin lithium alloy (Sn–20Li) was investigated by means of static corrosion tests. The corrosion tests were performed for reduced activation ferritic martensitic steel JLF-1 (JOYO-HEAT, Fe–9Cr–2W–0.1C) and austenitic steel SUS316 (Fe–18Cr–12Ni–2Mo). The test temperature was 873 K, and the exposure time was 250 and 750 h. The corrosion of these steels in liquid Ga, Sn and Sn–20Li alloy was commonly caused by the formation of a reaction layer and the dissolution of the steel elements into the melts. The reaction layer formed in liquid Ga was identified as Fe 3 Ga from the results of metallurgical analysis and the phase diagram. The growth rate of the reaction layer on the JLF-1 steel showed a parabolic rate law, and this trend indicated that the corrosion could be controlled by the diffusion process through the layer. The reaction layer formed in liquid Sn and Sn–20Li was identified as FeSn. The growth rate had a linear function with exposure time. The corrosion in Sn and Sn–20Li could be controlled by the interface reaction on the layer. The growth rate of the layer formed in

  16. Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

    KAUST Repository

    Kanoun, Mohammed; Goumri-Said, Souraya

    2014-01-01

    We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young's modulus, and Poisson's ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

  17. Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

    KAUST Repository

    Kanoun, Mohammed

    2014-09-01

    We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young\\'s modulus, and Poisson\\'s ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

  18. Characterization of Desulfovibrio desulfuricans biofilm on high-alloyed stainless steel: XPS and electrochemical studies

    Energy Technology Data Exchange (ETDEWEB)

    Dec, Weronika [Institute of Industrial Organic Chemistry, Branch Pszczyna, Doświadczalna Street 27, 43-200 Pszczyna (Poland); Mosiałek, Michał; Socha, Robert P. [Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, Niezapominajek Street 8, 30-239 Kraków (Poland); Jaworska-Kik, Marzena [Department of Biopharmacy, Medical University of Silesia, Jedności Street 8, 41-200 Sosnowiec (Poland); Simka, Wojciech [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego 6 Street, 44-100 Gliwice (Poland); Michalska, Joanna, E-mail: joanna.k.michalska@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego 6 Street, 44-100 Gliwice (Poland)

    2017-07-01

    Results on D. desulfuricans biofilm formation on austenitic-ferritic duplex (2205 DSS) and superaustenitic (904L) stainless steels are presented. Surface characterization including the structure, configuration and chemical composition of biofilms were carried out using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical impedance spectroscopy (EIS) measurements were used to monitor the attachment activity of bacteria on the steels' surface and to determine the effect of bacteria on passivity. It was proved that investigated steels are rapidly colonized by bacteria. The presence of biofilm caused significant ennoblement of 904L steel surface, while retarded the attainment of high passive state of 2205 DSS. XPS analysis revealed significant sulphidation of the biofilm and its layered structure. Accumulation of sulphides and hydroxides was proved in the outermost layer, while the increasing contents of disulphides, organometallic and C-N bonds were detected in the internal part of the biofilm. Irreversible bondings between steel matrix and biofilm had also been observed. - Highlights: • High-alloyed steels are rapidly colonized by sulphate-reducing bacteria. • Higher Ni content stimulates more intensive biofilm growth. • Extracellular polymeric substances indelibly bind to the high-alloyed steels. • Sulphate-reducing bacteria caused irreversible sulphidation of passive films.

  19. Characterization of Desulfovibrio desulfuricans biofilm on high-alloyed stainless steel: XPS and electrochemical studies

    International Nuclear Information System (INIS)

    Dec, Weronika; Mosiałek, Michał; Socha, Robert P.; Jaworska-Kik, Marzena; Simka, Wojciech; Michalska, Joanna

    2017-01-01

    Results on D. desulfuricans biofilm formation on austenitic-ferritic duplex (2205 DSS) and superaustenitic (904L) stainless steels are presented. Surface characterization including the structure, configuration and chemical composition of biofilms were carried out using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical impedance spectroscopy (EIS) measurements were used to monitor the attachment activity of bacteria on the steels' surface and to determine the effect of bacteria on passivity. It was proved that investigated steels are rapidly colonized by bacteria. The presence of biofilm caused significant ennoblement of 904L steel surface, while retarded the attainment of high passive state of 2205 DSS. XPS analysis revealed significant sulphidation of the biofilm and its layered structure. Accumulation of sulphides and hydroxides was proved in the outermost layer, while the increasing contents of disulphides, organometallic and C-N bonds were detected in the internal part of the biofilm. Irreversible bondings between steel matrix and biofilm had also been observed. - Highlights: • High-alloyed steels are rapidly colonized by sulphate-reducing bacteria. • Higher Ni content stimulates more intensive biofilm growth. • Extracellular polymeric substances indelibly bind to the high-alloyed steels. • Sulphate-reducing bacteria caused irreversible sulphidation of passive films.

  20. Nano-structureal and nano-chemical analysis of Ni-based alloy/low alloy steel dissimilar metal weld interfaces

    International Nuclear Information System (INIS)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun

    2012-01-01

    The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

  1. Nano-structureal and nano-chemical analysis of Ni-based alloy/low alloy steel dissimilar metal weld interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kyoung Joon; Shin, Sang Hun; Kim, Jong Jin; Jung, Ju Ang; Kim, Ji Hyun [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan (Korea, Republic of)

    2012-06-15

    The dissimilar metal joints welded between Ni-based alloy, Alloy 690 and low alloy steel, A533 Gr. B with Alloy 152 filler metal were characterized by using optical microscope, scanning electron microscope, transmission electron microscope, secondary ion mass spectrometry and 3-dimensional atom probe tomography. It was found that in the weld root region, the weld was divided into several regions including unmixed zone in Ni-base alloy, fusion boundary, and heat-affected zone in the low alloy steel. The result of nanostructural and nanochemical analyses in this study showed the non-homogeneous distribution of elements with higher Fe but lower Mn, Ni and Cr in A533 Gr. B compared with Alloy 152, and the precipitation of carbides near the fusion boundary.

  2. Behavior of the elements in the mechanically alloyed and cast ferritic steels and a type 316 stainless steel in a flowing sodium environment

    International Nuclear Information System (INIS)

    Suzuki, T.; Mutoh, I.

    1988-01-01

    Sodium corrosion behavior of a mechanically alloyed ferritic steel, dispersion-strengthened with addition of Y 2 0 3 and Ti, two kinds of melted/cast ferritic steels and a Type 316 stainless steel was examined by using a non-isothermal sodium loop system, constructed of another Type 316 stainless steel, with a direct resistance electrical heater. The sodium conditions were 675 0 C, 4.0 m/s in velocity and 1-2 ppm oxygen concentration and a cumulative exposure time of the specimens was about 3000 h. The absorption of Ni and selective dissolution of Cr played an important role in the corrosion of the mechanically alloyed ferritic steel as in the case of the cast ferritic steels. However, the region of Ni absorption and Cr diminution was deeper than that of the cast ferritic steels. Peculiar finding for the mechanically alloyed ferritic steel was the corroded surface with irregularly shaped protuberance, that might be related with formation of sodium titanate, and the absorption of carbon and nitrogen to form carbide and nitride of titanium. It seems that these facts resulted in the irregular weight loss of the specimens, which depended on the downstream position and the cumulative exposure time. However, the tensile properties of the mechanically alloyed ferritic steel did not noticeably change by the sodium exposure

  3. Thermal plasma synthesis of transition metal nitrides and alloys

    International Nuclear Information System (INIS)

    Ronsheim, P.; Christensen, A.N.; Mazza, A.

    1981-01-01

    Applications of arc plasma processing to high-temperature chemistry of Group V nitrides and Si and Ge alloys are studied. The transition metal nitrides 4f-VN, 4f-NbN, and 4f-TaN are directly synthesized in a dc argon-nitrogen plasma from powders of the metals. A large excess of N 2 is required to form stoichiometric 4f-VN, while the Nb and Ta can only be synthesized with a substoichiometric N content. In a dc argon plasma the alloys V 3 Si, VSi 2 , NbSi 2 , NbGe 2 , Cr 3 Si, and Mo 3 Si are obtained from powder mixtures of the corresponding elements. The compounds are identified by x-ray diffraction patterns and particle shape and size are studied by electron microscopy

  4. The Effect of Microstructure on the Abrasion Resistance of Low Alloyed Steels

    NARCIS (Netherlands)

    Xu, X.

    2016-01-01

    The thesis attempts to develop advanced high abrasion resistant steels with low hardness in combination with good toughness, processability and low alloying additions. For this purpose, a novel multi-pass dual-indenter (MPDI) scratch test approach has been developed to approach the real continuous

  5. Inverse Processing of Undefined Complex Shape Parts from Structural High Alloyed Tool Steel

    Czech Academy of Sciences Publication Activity Database

    Monková, K.; Monka, P.; Hloch, Sergej

    -, č. 1 (2014), s. 1-11 ISSN 1687-8132 Institutional support: RVO:68145535 Keywords : 3D digitization * complex shape parts * high alloyed tool steel Subject RIV: JQ - Machines ; Tools Impact factor: 0.575, year: 2014 http://www.hindawi.com/journals/ame/aip/478748/

  6. Practical measurement of silicon in low alloy steels by differential pulse stripping voltammetry

    International Nuclear Information System (INIS)

    Rahier, A.; Lunardi, S.; Triki, C.

    2005-01-01

    A sensitive differential pulse anodic stripping voltammetry has been adapted to allow the determination of Si in low-alloy steels using a hanging mercury drop electrode. The method has been qualified using certified ASTM standards and is now running in routine. The present report describes the experimental details, thereby allowing the reader to carry out the measurements precisely. (author)

  7. 75 FR 26273 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China

    Science.gov (United States)

    2010-05-11

    ...)] Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From China AGENCY: United States... materially injured or threatened with material injury, or the establishment of an industry in the United States is materially retarded, by reason of subsidized and less-than-fair-value imports from China of...

  8. Corrosion resistance of Zn-Co-Fe alloy coatings on high strength steel

    NARCIS (Netherlands)

    Lodhi, Z.F.; Mol, J.M.C.; Hovestad, A.; Hoen-Velterop, L. 't; Terryn, H.; Wit, J.H.W.de

    2009-01-01

    The corrosion properties of electrodeposited zinc-cobalt-iron (Zn-Co-Fe) alloys (up to 40 wt.% Co and 1 wt.% Fe) on steel were studied by using various electrochemical techniques and compared with zinc (Zn) and cadmium (Cd) coatings in 3.5% NaCl solution. It was found that with an increase in Co

  9. Improved hardness of laser alloyed X12CrNiMo martensitic stainless steel

    CSIR Research Space (South Africa)

    Adebiyi, DI

    2011-07-01

    Full Text Available The improvement in hardness of X12CrNiMo martensitic stainless steel laser alloyed with 99.9% pure titanium carbide, stellite 6 and two cases of premixed ratio of titanium carbide and stellite 6 [TiC (30 wt.%)- stellite 6 (70 wt.%) and TiC (70 wt...

  10. Effect of Mechanical Alloying Atmospheres and Oxygen Concentration on Mechanical Properties of ODS Ferritic Steels

    International Nuclear Information System (INIS)

    Noh, Sanghoon; Choi, Byoungkwon; Han, Changhee; Kim, Kibaik; Kang, Sukhoon; Chun, Youngbum; Kim, Taekyu

    2013-01-01

    Finely dispersed nano-oxide particles with a high number density in the homogeneous grain matrix are essential to achieve superior mechanical properties at high temperatures, and these unique microstructures can be obtained through the mechanical alloying (MA) and hot consolidation process. The microstructure and mechanical property of ODS steel significantly depends on its powder property and the purity after the MA process. These contents should be carefully controlled to improve the mechanical property at elevated temperature. In particular, appropriate the control of oxygen concentration improves the mechanical property of ODS steel at high temperature. An effective method is to control the mechanical alloying atmosphere by high purity inert gas. In the present study, the effects of mechanical alloying atmospheres and oxygen concentration on the mechanical property of ODS steel were investigated. ODS ferritic alloys were fabricated in various atmospheres, and the HIP process was used to investigate the effects of MA atmospheres and oxygen concentration on the microstructure and mechanical property. ODS ferritic alloys milled in an Ar-H 2 mixture, and He is effective to reduce the excess oxygen concentration. The YH 2 addition made an extremely reduced oxygen concentration by the internal oxygen reduction reaction and resulted in a homogeneous microstructure and superior creep strength

  11. Passivation of Cu-Zn alloy on low carbon steel electrodeposited from a pyrophosphate medium

    Science.gov (United States)

    Yavuz, Abdulcabbar; Yakup Hacıibrahimoğlu, M.; Bedir, Metin

    2018-01-01

    The motivation of this study is to understand whether zinc-based alloy also has a passivation behaviour similar to zinc itself. Cu-Zn alloys were electrodeposited potentiostatically from a pyrophosphate medium on a carbon steel electrode and their corrosion behaviours were studied. Pt and carbon steel electrodes were used in order to examine the corrosion/passivation behaviour of bare Cu, bare Zn and Cu-Zn alloy coatings. The passivation behaviour of all brass-modified electrodes having Zn content between 10% and 100% was investigated. The growth potential affects the morphology and structure of crystals. The brass coatings are more porous than their pure components. The crystalline structure of Cu-Zn alloys can be obtained by changing the deposition potential. The zinc content in brass increases when the deposition voltage applied decreases. However, the growth potential and the ratio of zinc in brass do not affect the passivation behaviour of the resulting alloys. The coatings obtained by applying different growth potentials were immersed in tap water for 24 h to compare their corrosion behaviours with carbon steel having pitting formation.

  12. Impurity content of reduced-activation ferritic steels and a vanadium alloy

    International Nuclear Information System (INIS)

    Klueh, R.L.; Grossbeck, M.L.; Bloom, E.E.

    1997-01-01

    Inductively coupled plasma mass spectrometry was used to analyze a reduced-activation ferritic/martensitic steel and a vanadium alloy for low-level impurities that would compromise the reduced-activation characteristics of these materials. The ferritic steel was from the 5-ton IEA heat of modified F82H, and the vanadium alloy was from a 500-kg heat of V-4Cr-4Ti. To compare techniques for analysis of low concentrations of impurities, the vanadium alloy was also examined by glow discharge mass spectrometry. Two other reduced-activation steels and two commercial ferritic steels were also analyzed to determine the difference in the level of the detrimental impurities in the IEA heat and steels for which no extra effort was made to restrict some of the tramp impurities. Silver, cobalt, molybdenum, and niobium proved to be the tramp impurities of most importance. The levels observed in these two materials produced with present technology exceeded the limits for low activation for either shallow land burial or recycling. The chemical analyses provide a benchmark for the improvement in production technology required to achieve reduced activation; they also provide a set of concentrations for calculating decay characteristics for reduced-activation materials. The results indicate the progress that has been made and give an indication of what must still be done before the reduced-activation criteria can be achieved

  13. Simultaneous Co-deposition of Zn-Mg Alloy Layers on Steel Strip by PVD Process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Yeob [POSCO Technical Research Laboratories, Gwangyang (Korea, Republic of); Goodenough, Mark [Strategic Marketing, Tata Steel, Warwickshire (United Kingdom)

    2011-12-15

    This is the first release of an interim report on the development of coating technology of Zn-Mg alloy layers on steel strip by EML-PVD (electromagnetic levitation - physical vapor deposition) process in an air-to-air type continuous PVD pilot plant. It intends to introduce a basic principle of the EML-PVD process together with the high speed PVD pilot plant built in Posco. Due to the agitation effect provided by the high frequency induction coil, simultaneous evaporation of Zn and Mg from a droplet could produce alloy coating layers with Mg content of 6% to 12% depending on the composition of the droplet inside the coil. For its superior corrosion resistance, Zn-Mg alloy coated steel would be a very promising material for automotive, electrical appliances, and construction applications.

  14. Perspective on present and future alloy development efforts on austenitic stainless steels for fusion application

    International Nuclear Information System (INIS)

    Maziasz, P.J.

    1984-01-01

    The purpose of this paper is to address important questions concerning how to effect further alloy development of austenitic stainless steels for resistance, and to what extent the behavior of other properties under irradiation, such as strength/embrittlement, fatigue/irradiation creep, corrosion (under irradiation), and radiation-induced activation must be influenced. To summarize current understanding, helium has been found to have major effects on swelling and embrittlement, but several metallurgical avenues are available for significant improvement relative to type 316 stainless steel. Studies on fatigue and irradiation creep, particularly including helium effects, are preliminary but have yet to reveal engineering problems requiring additional alloy development remedies. The effects of irradiation on corrosion behavior are unknown, but higher alloy nickel contents make thermal corrosion in lithium worse. 67 refs

  15. Simultaneous Co-deposition of Zn-Mg Alloy Layers on Steel Strip by PVD Process

    International Nuclear Information System (INIS)

    Kim, Tae Yeob; Goodenough, Mark

    2011-01-01

    This is the first release of an interim report on the development of coating technology of Zn-Mg alloy layers on steel strip by EML-PVD (electromagnetic levitation - physical vapor deposition) process in an air-to-air type continuous PVD pilot plant. It intends to introduce a basic principle of the EML-PVD process together with the high speed PVD pilot plant built in Posco. Due to the agitation effect provided by the high frequency induction coil, simultaneous evaporation of Zn and Mg from a droplet could produce alloy coating layers with Mg content of 6% to 12% depending on the composition of the droplet inside the coil. For its superior corrosion resistance, Zn-Mg alloy coated steel would be a very promising material for automotive, electrical appliances, and construction applications

  16. Adsorption and inhibitive properties of Tryptophan on low alloy steel corrosion in acidic media

    Directory of Open Access Journals (Sweden)

    Hesham T.M. Abdel-Fatah

    2017-02-01

    Corrosion inhibition was studied using electrochemical methods (electrochemical impedance spectroscopy; EIS and the new technique electrochemical frequency modulation; EFM and weight loss measurements. The influence of inhibitor concentration, solution temperature, and immersion time on the corrosion resistance of low alloy steel (LAS has been investigated. Trp proved to be a very good inhibitor for low alloy steel acid corrosion. EFM measurements showed that Trp is a mixed type inhibitor. Trp behaved better in 0.6 M HCl than in 0.6 M HSO3NH2. Moreover, it was found that the inhibition efficiency increased with increasing inhibitor concentration, while a decrease was detected with the rise of temperature and immersion time. The associated activation energy (Ea has been determined. The values of Ea indicate that the type of adsorption of Trp on the steel surface in both acids belongs to physical adsorption. The adsorption process was tested using Temkin adsorption isotherm.

  17. Application of Different Extraction Methods for Investigation of Nonmetallic Inclusions and Clusters in Steels and Alloys

    Directory of Open Access Journals (Sweden)

    Diana Janis

    2014-01-01

    Full Text Available The characterization of nonmetallic inclusions is of importance for the production of clean steel in order to improve the mechanical properties. In this respect, a three-dimensional (3D investigation is considered to be useful for an accurate evaluation of size, number, morphology of inclusions, and elementary distribution in each inclusion particle. In this study, the application of various extraction methods (chemical extraction/etching by acid or halogen-alcohol solutions, electrolysis, sputtering with glow discharge, and so on for 3D estimation of nonmetallic Al2O3 inclusions and clusters in high-alloyed steels was examined and discussed using an Fe-10 mass% Ni alloy and an 18/8 stainless steel deoxidized with Al. Advantages and limitations of different extraction methods for 3D investigations of inclusions and clusters were discussed in comparison to conventional two-dimensional (2D observations on a polished cross section of metal samples.

  18. Thermal Effects That Arise upon Different Heat Treatments in Austenitic Steels Alloyed with Titanium and Phosphorus

    Science.gov (United States)

    Arbuzov, V. L.; Berger, I. F.; Bobrovskii, V. I.; Voronin, V. I.; Danilov, S. E.; Kazantsev, V. A.; Kataev, N. V.; Sagaradze, V. V.

    2018-04-01

    Structural and microstructural changes that arise in the course of the heat treatment of Cr-Ni-Mo austenitic stainless steels with different concentrations of titanium and phosphorus have been studied. It has been found that the alloying with phosphorus decreases the lattice parameter of these steels. The phosphorus contribution to this effect is 0.015 ± 0.002 Å/at %. Aging at a temperature of 670 K for about 20 h leads to the precipitation of dispersed needle-like particles, which are most likely to be iron phosphides. In the temperature range of 700-800 K, in austenitic steels, the atomic separation of the solid solution occurs, the intensity of which decreases upon alloying with titanium or phosphorus at concentrations of 1.0 and 0.1 wt %, respectively. At higher temperatures (about 950 K), the formed precipitates of the Ni3Ti (γ') phase increase in size to 7-10 nm.

  19. Investigation of models to predict the corrosion of steels in flowing liquid lead alloys

    International Nuclear Information System (INIS)

    Balbaud-Celerier, F.; Barbier, F.

    2001-01-01

    Corrosion of steels exposed to flowing liquid lead alloys can be affected by hydrodynamic parameters. The rotating cylinder system is of interest for the practical evaluation of the fluid velocity effect on corrosion and for the prediction of the corrosion behavior in other geometries. Models developed in aqueous medium are tested in the case of liquid metal environments. It is shown that equations established for the rotating cylinder and the pipe flow geometry can be used effectively in liquid lead alloys (Pb-17Li) assuming the corrosion process is mass transfer controlled and the diffusion coefficient of dissolved species is known. The corrosion rate of martensitic steels in Pb-17Li is shown to be independent of the geometry when plotted as a function of the mass transfer coefficient. Predictions about the corrosion of steel in liquid Pb-Bi are performed but experiments are needed to validate the results obtained by modeling

  20. Phase transitions in alloys of the Ni-Mo system

    International Nuclear Information System (INIS)

    Ustinovshikov, Y.; Shabanova, I.

    2011-01-01

    Graphical abstract: The structure of Ni-20 at.% Mo and Ni-25 at.% Mo alloys was studied by methods of TEM and XPS. It is shown that at high temperatures the tendency toward phase separation takes place in the alloys and crystalline bcc Mo particles precipitate in the liquid solution. At 900 deg. C and below, the tendency toward ordering leads to the dissolution of Mo particles and precipitation of the particles of Ni 3 Mo, Ni 2 Mo or Ni 4 Mo chemical compounds. Highlights: → 'Chemical' phase transition 'ordering-phase separation' is first discovered in alloys of the Ni-Mo system. → It is first shown that the phase separation in the alloys studied begins at temperatures above the liquidus one. → The formation of Ni 3 Mo from A1 has gone through the intervening stage of the Ni 4 Mo and Ni 2 Mo coexistence. - Abstract: The structure of Ni-20 at.% Mo and Ni-25 at.% Mo alloys heat treated at different temperatures was studied by the method of transmission electron microscopy. X-ray photoelectron spectroscopy was used to detect the sign of the chemical interaction between Ni and Mo atoms at different temperatures. It is shown that at high temperatures the tendency toward phase separation takes place. The system of additional reflections at positions {1 1/2 0} on the electron diffraction patterns testifies that the precipitation of crystalline bcc Mo particles begins in the liquid solution. At 900 deg. C and below, the tendency toward ordering leads to the precipitation of the particles of the chemical compounds. A body-centered tetragonal phase Ni 4 Mo (D1 a ) is formed in the Ni-20 at.% Mo alloy. In the Ni-25 at.% Mo alloy, the formation of the Ni 3 Mo (D0 22 ) chemical compound from the A1 solid solution has gone through the intervening stage of the Ni 4 Mo (D1 a ) and Ni 2 Mo (Pt 2 Mo) formation.

  1. The Effects of Alloy Chemistry on Localized Corrosion of Austenitic Stainless Steels

    Science.gov (United States)

    Sapiro, David O.

    This study investigated localized corrosion behavior of austenitic stainless steels under stressed and unstressed conditions, as well as corrosion of metallic thin films. While austenitic stainless steels are widely used in corrosive environments, they are vulnerable to pitting and stress corrosion cracking (SCC), particularly in chloride-containing environments. The corrosion resistance of austenitic stainless steels is closely tied to the alloying elements chromium, nickel, and molybdenum. Polarization curves were measured for five commercially available austenitic stainless steels of varying chromium, nickel, and molybdenum content in 3.5 wt.% and 25 wt.% NaCl solutions. The alloys were also tested in tension at slow strain rates in air and in a chloride environment under different polarization conditions to explore the relationship between the extent of pitting corrosion and SCC over a range of alloy content and environment. The influence of alloy composition on corrosion resistance was found to be consistent with the pitting resistance equivalent number (PREN) under some conditions, but there were also conditions under which the model did not hold for certain commercial alloy compositions. Monotonic loading was used to generate SCC in in 300 series stainless steels, and it was possible to control the failure mode through adjusting environmental and polarization conditions. Metallic thin film systems of thickness 10-200 nm are being investigated for use as corrosion sensors and protective coatings, however the corrosion properties of ferrous thin films have not been widely studied. The effects of film thickness and substrate conductivity were examined using potentiodynamic polarization and scanning vibrating electrode technique (SVET) on iron thin films. Thicker films undergo more corrosion than thinner films in the same environment, though the corrosion mechanism is the same. Conductive substrates encourage general corrosion, similar to that of bulk iron

  2. Zr/ZrC modified layer formed on AISI 440B stainless steel by plasma Zr-alloying

    Science.gov (United States)

    Shen, H. H.; Liu, L.; Liu, X. Z.; Guo, Q.; Meng, T. X.; Wang, Z. X.; Yang, H. J.; Liu, X. P.

    2016-12-01

    The surface Zr/ZrC gradient alloying layer was prepared by double glow plasma surface alloying technique to increase the surface hardness and wear resistance of AISI 440B stainless steel. The microstructure of the Zr/ZrC alloying layer formed at different alloying temperatures and times as well as its formation mechanism were discussed by using scanning electron microscopy, glow discharge optical emission spectrum, X-ray diffraction and X-ray photoelectron spectroscopy. The adhesive strength, hardness and tribological property of the Zr/ZrC alloying layer were also evaluated in the paper. The alloying surface consists of the Zr-top layer and ZrC-subsurface layer which adheres strongly to the AISI 440B steel substrate. The thickness of the Zr/ZrC alloying layer increases gradually from 16 μm to 23 μm with alloying temperature elevated from 900 °C to 1000 °C. With alloying time from 0.5 h to 4 h, the alloyed depth increases from 3 μm to 30 μm, and the ZrC-rich alloyed thickness vs time is basically parabola at temperature of 1000 °C. Both the hardness and wear resistance of the Zr/ZrC alloying layer obviously increase compared with untreated AISI 440B steel.

  3. Development of high nickel austenitic steels for the application to fast reactor cores, (I). Alloy design with the aid of the d-electrons concept

    International Nuclear Information System (INIS)

    Murata, Yoshinori; Morinaga, Masahiko; Yukawa, Natsuo; Ukai, Shigeharu; Nomura, Shigeo; Okuda, Takanari; Harada, Makoto

    1999-01-01

    The design of high nickel austenitic steels for the core materials of the fast reactors was performed following the d-electrons concept devised on the basis of molecular orbital calculations of transition-metal based alloys. In this design two calculated parameters are mainly utilized. The one is the d-orbital energy level (Md) of alloying transition elements, and the other is the bond order (Bo) that is a measure of the covalent bond strength between atoms. Using the Md-bar - Bo-bar phase stability diagram accurate prediction become possible for the phase stability of the austenite phase and 5% swelling at 140 dpa for nickel ions. Here, Md-bar and Bo-bar are the compositional average of Md and Bo parameters, respectively. On the basis of the phase stability diagram and preliminary experiments, guidelines for the alloy design of carbo-nitrides precipitated high nickel austenitic steels were constructed. Following the guidelines several new austenitic steels were designed for the fast reactors core material. (author)

  4. Resistance of heat resisting steels and alloys to thermal and mechanical low-cycle fatigue

    International Nuclear Information System (INIS)

    Tulyakov, G.A.

    1980-01-01

    Carried out is a comparative evalUation of resistance of different materials to thermocyclic deformation and fracture on the base of the experimental data on thermal and mechanical low-cycle fatigUe. Considered are peculiarities of thermal fatigue resistance depending on strength and ductility of the material. It is shown, that in the range of the cycle small numbers before the fracture preference is given to the high-ductility cyclically strengthening austenitic steels of 18Cr-10Ni type with slight relation of yield strength to the σsub(0.2)/σsub(B) tensile strength Highly alloyed strength chromium-nickel steels, as well as cyclically destrengthening perlitic and ferritic steels with stronger σsub(0.2)/σsub(B) relation as compared with simple austenitic steels turn to be more long-lived in the range of the cycle great numbers berore fracture. Perlitic steels are stated to have the lowest parameter values of the K crack growth intensity under the similar limiting conditions of the experiment, while steels and alloys with austenite structure-higher values of the K parameter

  5. Investigation of fretting corrosion of vacuum-chrome-plated vt3-1 titanium alloy in pair with unprotected vt3-1 alloy and 40khnma steel

    International Nuclear Information System (INIS)

    Rojkh, I.L.; Koltunova, L.N.; Vejtsman, M.G.; Birman, Ya.N.; Skosarev, A.V.; Kogan, I.S.

    1978-01-01

    The character of destruction of contacting surfaces in the process of fretting corrosion of titanium alloy VT3-1 chromized in vacuum in pair with unprotected alloy VT3-1 and steel 40KhNMA has been studied by scanning electron microscopy, electronography, and recording the surface profile. The specific load was 200 kg/cm 2 , vibration amplitude 50 mkm and frequency 500 Hz. It has been established that pairs unprotected with coating are subjected to intensive fretting corrosion especially when they are made of titanium alloy. For the pair chromized alloy VT3-1 - unprotected alloy VT3-1 no destruction of a chromized surface is observed. Vacuum chromium coating in the pair with steel 40KhNMA reveals similar properties as in pair with a titanium alloy. The surface of a steel sample is destroyed because of fretting corrosion, though the intensity of corrosion is lower than in the case of unprotected pairs. Vacuum chromium coating is recommended for protection of titanium alloy VT3-1 from fretting corrosion in pair with steel 40KhNMA or an alloy VT3-1 especially in those cases when various organic coatings are unsuitable

  6. Nickel-based materials and high-alloy, special stainless steels. 2. new rev. and enl. ed.

    International Nuclear Information System (INIS)

    Heubner, U.; Brill, U.; Hoffmann, T.; Jasner, M.; Kirchheiner, R.; Koecher, R.; Richter, H.; Rockel, M.; White, F.

    1993-01-01

    The book is intended as a source of information on nickel-based materials and special stainless steels and apart from the up-to-date materials data presents information on recent developments and knowledge gained, so that it may be a valuable aid to materials engineers looking for cost-effective resolutions of their materials problems in the chemical process industry, power plant operation, and high-temperature applications. The book presents eight individual contributions entitled as follows: (1) Nickel-base alloys and high-alloy, special stainless steels. - Materials survey and data sheets (Ulrich Heubner). (2) Corrosion of nickel-base alloys and special stainless steels (Manfred Rockel). (3) Welding of nickel-base alloys and high-alloy, special stainless steels (Theo Hoffmann). (4) High-temperature resistant materials (Ulrich Brill). (5) Application and processing of nickel-base materials in the chemical process industry and in pollution abatement equipment (Reiner Koecher). (6) Selected examples of applications of nickel-base materials in chemical plant (Manfred Jasner, Frederick White). (7) Applications of nickel-base alloys and special stainless steels in power plant. (8) The use of nickel-base alloys and stainless steels in pollution abatement processes (R. Kirchheiner). (orig./MM). 151 figs., 226 refs [de

  7. Alloying and heat treatment optimization of Fe/Cr/C steels for improved mechanical properties

    International Nuclear Information System (INIS)

    Sarikaya, M.

    1979-06-01

    The effects of alloying elements and heat treatments on the microstructural changes and strength-toughness properties were investigated in optimization of vacuum melted Fe/Cr/C base steels. The structure of the steels in the as-quenched conditions consisted of highly dislocated autotempered lath martensite (strong phase) and thin continuous interlath films of retained austenite (tough phase). It has been emphasized again that the mechanical properties of the steels are sensitive to the amount and the stability of retained austenite. To increase the stability of retained austenite in the as-quenched condition 2 w/o Mn or 2 w/o Ni was added to the base steel, viz., Fe/3Cr/0.3C. Partial replacement of Cr by about 0.5 w/o Mo did not alter the beneficial microstructure

  8. Formability of high-alloy dual-phase Cr-Ni steels

    International Nuclear Information System (INIS)

    Elfmark, J.

    2004-01-01

    The formability of dual-phase high-alloy Cr-Ni steel within the temperature range from 900 to 1250 C was studied using laboratory tensile and torsion tests. The dual-phase steels on 24% Cr basis are characterized by poor hot formability due to very low stable deformation values and slow recrystallization. Mathematical description of deformation stability exhaustion was derived, as well as a model of formability control based on analysis of the gradual diffuse deformation stability from the stability limit to the moment when the deformation starts to concentrate in a small volume of the test piece. Rolling simulation of dual-phase steel strip was used as an example demonstrating the draught scheme optimization technique which avoids the danger of crack occurrence during the rolling of dual-phase steel strip. (orig.)

  9. Austenitic stainless steels and high strength copper alloys for fusion components

    International Nuclear Information System (INIS)

    Rowcliffe, A.F.; Zinkle, S.J.; Alexander, D.J.; Stubbins, J.F.

    1998-01-01

    An austenitic stainless steel (316LN), an oxide-dispersion-strengthened copper alloy (GlidCop A125), and a precipitation-hardened copper alloy (Cu-Cr-Zr) are the primary structural materials for the ITER first wall/blanket and divertor systems. While there is a long experience of operating 316LN stainless steel in nuclear environments, there is no prior experience with the copper alloys in neutron environments. The ITER first wall (FW) consists of a stainless steel shield with a copper alloy heat sink bonded by hot isostatic pressing (HIP). The introduction of bi-layer structural material represents a new materials engineering challenge; the behavior of the bi-layer is determined by the properties of the individual components and by the nature of the bond interface. The development of the radiation damage microstructure in both classes of materials is summarized and the effects of radiation on deformation and fracture behavior are considered. The initial data on the mechanical testing of bi-layers indicate that the effectiveness of GlidCop A125 as a FW heat sink material is compromised by its strongly anisotropic fracture toughness and poor resistance to crack growth in a direction parallel to the bi-layer interface. (orig.)

  10. Nitride alloy layer formation of duplex stainless steel using nitriding process

    Science.gov (United States)

    Maleque, M. A.; Lailatul, P. H.; Fathaen, A. A.; Norinsan, K.; Haider, J.

    2018-01-01

    Duplex stainless steel (DSS) shows a good corrosion resistance as well as the mechanical properties. However, DSS performance decrease as it works under aggressive environment and at high temperature. At the mentioned environment, the DSS become susceptible to wear failure. Surface modification is the favourable technique to widen the application of duplex stainless steel and improve the wear resistance and its hardness properties. Therefore, the main aim of this work is to nitride alloy layer on the surface of duplex stainless steel by the nitriding process temperature of 400°C and 450°C at different time and ammonia composition using a horizontal tube furnace. The scanning electron microscopy and x-ray diffraction analyzer are used to analyse the morphology, composition and the nitrided alloy layer for treated DSS. The micro hardnesss Vickers tester was used to measure hardness on cross-sectional area of nitrided DSS. After nitriding, it was observed that the hardness performance increased until 1100 Hv0.5kgf compared to substrate material of 250 Hv0.5kgf. The thickness layer of nitride alloy also increased from 5μm until 100μm due to diffusion of nitrogen on the surface of DSS. The x-ray diffraction results showed that the nitride layer consists of iron nitride, expanded austenite and chromium nitride. It can be concluded that nitride alloy layer can be produced via nitriding process using tube furnace with significant improvement of microstructural and hardness properties.

  11. APFIM investigation of clustering in neutron-irradiated Fe-Cu alloys and pressure vessel steels

    International Nuclear Information System (INIS)

    Auger, P.; Pareige, P.; Blavette, D.

    1996-01-01

    Pressure vessel steels used in PWRs are known to be prone to hardening and embrittlement under neutron irradiation. The changes in mechanical properties are commonly supposed to result from the formation of point defects, dislocation loops, voids and copper-rich precipitates. However, the real nature of the irradiation induced damage, in these particularly low copper steels (>0,1 wt%), has not been clearly identify yet. A new experimental work has been carried out thanks to atom probe and field ion microscopy (APFIM) facilities and, more particularly with a new generation of atom probe recently developed, namely the tomographic atom probe (TAP), in order to improve: the understanding of the complex behavior of copper precipitation which occurs when low-alloyed Fe-Cu model alloys are irradiated with neutrons; the microstructural characterization of the pressure vessel steel of the CHOOZ A reactor under various fluences (French Surveillance Programme). The investigations clearly reveal the precipitation of copper-rich clusters in irradiated Fe-Cu alloys while more complicated Si, Ni, Mn and Cu-solute 'clouds' were observed to develop in the low-copper ferritic solid solution of the pressure vessel steel. (authors)

  12. Evaluation of microstructural difference in low alloy steel (SA508 CI.3) by magnetic measurements

    International Nuclear Information System (INIS)

    Chi, Se Hwan; Park, Duck Gun; Hong, Jun Hwa; Kuk, Il Hium; Song, Sook Hyang; Shur, Dong Soo

    1997-01-01

    Magnetic measurements on SA 508 Cl. 3 low alloy reactor pressure vessel (RPV) steels of three different refining processes were conducted to prepare baseline magnetic properties for future comparison with that of irradiated one and to examine the correlation between microstructures and magnetic parameters. TEM(transmission electron microscopy) on thin films and carbon replications were performed for microstructural investigation, and microhardness, tensile and fracture toughness tests were conducted for mechanical properties measurement. Barkhausen noise analysis was conducted and hysteresis parameters were measured. Microstructure, mechanist and magnetic properties were interpreted together to explore their inter-relationship. Also the applicability of a magnetic nondestructive evaluation method for monitoring fine microstructural changes in low alloy steels of complicated microstructure was examined. The results showed that, of all magnetic parameters, Barkhausen noise amplitudes show consistent change with microstructure (grain size, carbide microstructure, lath width) and hardness of the materials. For monitoring microstructural and mechanical property changes of low alloy steel under service environment of reactor pressure vessel steels, Barkhausen noise amplitude and coercivity appear to be as key magnetic parameters useful for nondestructive evaluation.

  13. Evaluation of interfacial microstructures in dissimilar joints of aluminum alloys to steel using nanoindentation technique

    International Nuclear Information System (INIS)

    Ogura, Tomo; Hirose, Akio; Saito, Yuichi; Ueda, Keisuke

    2009-01-01

    The characteristics of interfacial microstructures with additional elements in dissimilar 6000 system aluminum/steel joints were basically evaluated using tensile test, EPMA, TEM and nanoindentation. For Si (and Cu)-added alloy (S1 and SC), EPMA analysis showed that Si (and Cu) was enrichment in the reaction layers, which were formed during diffusion bonding. SAED pattern clarified that the reaction compounds at the interface changed from AlFe intermetalic compounds to AlFeSi intermetalic compounds by Si addition. Nanoindentation technique was successfully applied to the interfacial microstructures to understand directly the nanoscopic mechanical properties in the interfacial microstructures. The hardness and Young's modulus of Al 3 Fe intermetalic compounds was lower than those of Al 2 Fe 5 intermetalic compounds. Moreover, the hardness and Young's modulus of AlFeSi(Cu) compounds were lower than those of Al 3 Fe, indicating that the crystal system changed from orthorhombic structure to cubic structure. Joint strength of SC/steel joints was higher than that of the aluminum alloy with no additional element (Base)/ steel joint, indicating that interfacial microstructure was modified by the addition of Si and Cu to the 6000 system aluminum alloy. These results suggest that the nanoscopic mechanical properties at the interface microstructures affect greatly the macroscopic deformation behavior of the aluminum /steel dissimilar joints.

  14. Effect of nitrogen alloying on the microstructure and abrasive wear of stainless steels

    International Nuclear Information System (INIS)

    Hawk, J.A.; Simmons, J.W.; Rawers, J.C.

    1994-01-01

    Alloying stainless steels with nitrogen has distinct advantages. Nitrogen is a strong austenite stabilizer and a potent solid-solution strengthener, and nitrogen has greater solubility than carbon iron. This study investigates the relationship among nitrogen concentration, precipitate microstructure, and abrasive wear using two high-nitrogen stainless steel alloys: Fe-19Cr-5Mn-5Ni-3Mo (SS1) and Fe-16Cr-7Mn-5Ni(SS2). Alloy SS1 contained 0.7 wt% N and was solution annealed at 1,150 C, thereby dissolving the nitrogen interstitially in the austenite. Subsequent aging, or cold work and aging, at 900 C led to the grain-boundary, cellular, and transgranular precipitation of Cr 2 N. Alloy SS2 was remelted in a high-pressure (200 MPa) N 2 atmosphere, leading to a spatial gradient of nitrogen in the alloy in the form of interstitial nitrogen and Cr 2 N and CrN precipitates. Nitrogen contents varied from a low of approximately 0.7 wt% at the bottom of the billet to a high of 3.6 wt% at the top. Nitrogen in excess of approximately 0.7 wt% formed increasingly coarser and more numerous Cr 2 N and CrN precipitates. The precipitate morphology created in alloy SS1 due to aging, or cold work and aging, had little effect on the abrasive wear of the alloy. However, a decrease in the abrasive wear rate in alloy SS2 was observed to correspond to the increase in number and size of the Cr 2 N and CrN precipitates

  15. Zr/ZrC modified layer formed on AISI 440B stainless steel by plasma Zr-alloying

    Energy Technology Data Exchange (ETDEWEB)

    Shen, H.H.; Liu, L.; Liu, X.Z.; Guo, Q.; Meng, T.X.; Wang, Z.X.; Yang, H.J.; Liu, X.P., E-mail: liuxiaoping@tyut.edu.cn

    2016-12-01

    Highlights: • A Zr/ZrC modified layer was formed on AISI 440B stainless steel using plasma surface Zr-alloying. • The thickness of the modified layer increases with alloying temperature and time. • Formation mechanism of the modified layer is dependent on the mutual diffusion of Zr and substrate elements. • The modified surface shows an improved wear resistance. - Abstract: The surface Zr/ZrC gradient alloying layer was prepared by double glow plasma surface alloying technique to increase the surface hardness and wear resistance of AISI 440B stainless steel. The microstructure of the Zr/ZrC alloying layer formed at different alloying temperatures and times as well as its formation mechanism were discussed by using scanning electron microscopy, glow discharge optical emission spectrum, X-ray diffraction and X-ray photoelectron spectroscopy. The adhesive strength, hardness and tribological property of the Zr/ZrC alloying layer were also evaluated in the paper. The alloying surface consists of the Zr-top layer and ZrC-subsurface layer which adheres strongly to the AISI 440B steel substrate. The thickness of the Zr/ZrC alloying layer increases gradually from 16 μm to 23 μm with alloying temperature elevated from 900 °C to 1000 °C. With alloying time from 0.5 h to 4 h, the alloyed depth increases from 3 μm to 30 μm, and the ZrC-rich alloyed thickness vs time is basically parabola at temperature of 1000 °C. Both the hardness and wear resistance of the Zr/ZrC alloying layer obviously increase compared with untreated AISI 440B steel.

  16. A fracture mechanics approach for estimating fatigue crack initiation in carbon and low-alloy steels in LWR coolant environments

    International Nuclear Information System (INIS)

    Park, H. B.; Chopra, O. K.

    2000-01-01

    A fracture mechanics approach for elastic-plastic materials has been used to evaluate the effects of light water reactor (LWR) coolant environments on the fatigue lives of carbon and low-alloy steels. The fatigue life of such steel, defined as the number of cycles required to form an engineering-size crack, i.e., 3-mm deep, is considered to be composed of the growth of (a) microstructurally small cracks and (b) mechanically small cracks. The growth of the latter was characterized in terms of ΔJ and crack growth rate (da/dN) data in air and LWR environments; in water, the growth rates from long crack tests had to be decreased to match the rates from fatigue S-N data. The growth of microstructurally small cracks was expressed by a modified Hobson relationship in air and by a slip dissolution/oxidation model in water. The crack length for transition from a microstructurally small crack to a mechanically small crack was based on studies on small crack growth. The estimated fatigue S-N curves show good agreement with the experimental data for these steels in air and water environments. At low strain amplitudes, the predicted lives in water can be significantly lower than the experimental values

  17. ''Global and local approaches of fracture in the ductile to brittle regime of a low alloy steel''

    International Nuclear Information System (INIS)

    Renevey, S.

    1998-01-01

    The study is a contribution to the prediction of flow fracture toughness of low alloy steel and to a better knowledge of fracture behavior in the ductile to brittle transition region. Experiments were performed on a nozzle cut-off from a pressurized water reactor vessel made of steels A508C13 type steel. Axisymmetrical notched specimens were tested to study the fracture onset in a volume element while pre-cracked specimens were used to investigate cleavage fracture after stable crack growth. Systematic observations of fracture surfaces showed manganese sulfide inclusions (MnS) at cleavage sites or in the vicinity. The experimental results were used for modelling by the local approach to fracture. In a volume element the fracture is described by an original probabilistic model. This model is based on volume fraction distributions of MnS inclusions gathered in clusters and on the assumption of a competition without interaction between ductile and cleavage fracture modes. This model was applied to pre-cracked specimens (CT specimens). It is able to describe the scatter in the toughness after a small stable crack growth if a temperature effect on the cleavage stress is assumed. So, the modelling is able to give a lower bound of fracture toughness as a function of temperature. (author)

  18. Replacement of steel parts with extruded aluminum alloys in an automobile

    Science.gov (United States)

    Daggula, Manikantha Reddy

    Over the past years, vehicle emissions have shown a negative impact on environment and human health. A new strategy has been used by automakers to reduce a vehicle's weight which significantly reduce fuel consumption and C02 emissions. A very light car consumes very less fuel as it needs to overcome less inertia, decreasing the required power to movie the vehicle. Reducing weight is the easiest way to increase fuel economy and making it by just 10% can increase its efficiency 6 to 8 percent. For a normal scale 80% of vehicles weight is shared among chassis, power train and other exterior components. Almost 60% of the vehicles weight is comprised of steel and the remaining is with cast and extruded aluminum and magnesium alloys. Our main aim is to look for the parts like Fuel tank holder, Fuel filler neck, Turbo inlet assembly, and Brake lines, Dash board frame which are made from steel and replace them with extruded aluminum alloys, to analyze a conventional rear wheel aluminum drive shaft and replace it with a new design and with a new aluminum alloy. The current project involves dismantling an automobile and looking for feasible steel parts and making samples, analyzing the hardness of the samples. These parts are optimally analyzed using Ansys Finite element analysis tool, these parts are subjected to the constraints such as three-point bending, tensile testing, hydrostatic pressure and also torsional stress action on the drive shaft, the deformation and stress are observed in these parts. The results show the current steel parts can be replaced with 3000 series aluminum alloy and the drive shaft can be replaced with new design with 6061-T6 Al-alloy which decreases 25% of the shaft weight.

  19. Spin glass transition in canonical AuFe alloys: A numerical study

    International Nuclear Information System (INIS)

    Zhang, Kai-Cheng; Li, Yong-Feng; Liu, Gui-Bin; Zhu, Yan

    2012-01-01

    Although spin glass transitions have long been observed in diluted magnetic alloys, e.g. AuFe and CuMn alloys, previous numerical studies are not completely consistent with the experiment results. The abnormal critical exponents of the alloys remain still puzzling. By employing parallel tempering algorithm with finite-size scaling analysis, we investigated the phase transitions in canonical AuFe alloys. Our results strongly support that spin glass transitions occur at finite temperatures in the alloys. The calculated critical exponents agree well with those obtained from experiments. -- Highlights: ► By simulation we investigated the abnormal critical exponents observed in canonical SG alloys. ► The critical exponents obtained from our simulations agree well with those measured from experiments. ► Our results strongly support that RKKY interactions lead to SG transitions at finite temperatures.

  20. 75 FR 78216 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2010-12-15

    ... Non-Alloy Steel Pipe from Brazil, the Republic of Korea (Korea), Mexico, and Venezuela and Amendment..., Director, Office 7 to Michael Walsh, Director, AD/CVD Revenue Policy & Programs, U.S. Customs and Border...

  1. Microscopy of Alloy Formation on Arc Plasma Sintered Oxide Dispersion Strengthen (ODS) Steel

    Science.gov (United States)

    Bandriyana, B.; Sujatno, A.; Salam, R.; Dimyati, A.; Untoro, P.

    2017-07-01

    The oxide dispersed strengthened (ODS) alloys steel developed as structure material for nuclear power plants (NPP) has good resistant against creep due to their unique microstructure. Microscopy investigation on the microstructure formation during alloying process especially at the early stages was carried out to study the correlation between structure and property of ODS alloys. This was possible thanks to the arc plasma sintering (APS) device which can simulate the time dependent alloying processes. The ODS sample with composition of 88 wt.% Fe and 12 wt.% Cr powder dispersed with 1 wt.% ZrO2 nano powder was mixed in a high energy milling, isostatic compressed to form sample coins and then alloyed in APS. The Scanning Electron Microscope (SEM) with X-ray Diffraction Spectroscopy (EDX) line scan and mapping was used to characterize the microstructure and elemental composition distribution of the samples. The alloying process with unification of each Fe and Cr phase continued by the alloying formation of Fe-Cr by inter-diffusion of both Fe and Cr and followed by the improvement of the mechanical properties of hardness.

  2. Optimization of mechanical alloying parameters in 12YWT ferritic steel nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Rahmanifard, R., E-mail: rahmanifrd@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Advanced Materials Group, School of Materials Research, NSTRC, P.O. Box 31585-4395 Karaj (Iran, Islamic Republic of); Farhangi, H. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Novinrooz, A.J. [Advanced Materials Group, School of Materials Research, NSTRC, P.O. Box 31585-4395 Karaj (Iran, Islamic Republic of)

    2010-10-15

    Research highlights: {yields} Detailed studies of microstructural properties of ODS steels. {yields} Investigation of effects of different mechanical alloying parameters such as milling time; milling speed; ball-to-powder weight ratio and ball diameter on the microstructural characteristics. {yields} Interpretation of the experimental data using theoretical model by X-ray diffraction line profile analysis. - Abstract: The effects of different mechanical alloying parameters on the microstructural characteristics and morphology of ODS-ferritic steel nanocomposite powders were investigated. The steady state between the welding and fracturing of the particles was obtained within about 30 h using 8 mm ball diameter and 420 rpm milling speed with the ball-to-powder weight ratio of 10:1. However, for perfect dissolution of the used alloying elements, the mechanical alloying process must be continued up to 80 h of milling. Evaluation of the microstructural characteristics calculated by X-ray diffraction profile analysis revealed that although the average crystallite size reduced more sharply at the initial milling stages under the above conditions, with further milling, it eventually reached nearly the same value in all specimens. The distribution changes of crystallite size also showed a similar behavior of crystallite size. Among the investigated mechanical alloying parameters, milling speed had a considerable effect on the dislocation density so that it was reduced by about one order of magnitude when the milling speed decreased from 420 to 300 rpm.

  3. Braze alloy process and strength characterization studies for 18 nickel grade 200 maraging steel with application to wind tunnel models

    Science.gov (United States)

    Bradshaw, James F.; Sandefur, Paul G., Jr.; Young, Clarence P., Jr.

    1991-01-01

    A comprehensive study of braze alloy selection process and strength characterization with application to wind tunnel models is presented. The applications for this study include the installation of stainless steel pressure tubing in model airfoil sections make of 18 Ni 200 grade maraging steel and the joining of wing structural components by brazing. Acceptable braze alloys for these applications are identified along with process, thermal braze cycle data, and thermal management procedures. Shear specimens are used to evaluate comparative shear strength properties for the various alloys at both room and cryogenic (-300 F) temperatures and include the effects of electroless nickel plating. Nickel plating was found to significantly enhance both the wetability and strength properties for the various braze alloys studied. The data are provided for use in selecting braze alloys for use with 18 Ni grade 200 steel in the design of wind tunnel models to be tested in an ambient or cryogenic environment.

  4. Microstructural features of dissimilar welds between 316LN austenitic stainless steel and alloy 800

    International Nuclear Information System (INIS)

    Sireesha, M.; Sundaresan, S.

    2000-01-01

    For joining type 316LN austenitic stainless steel to modified 9Cr-1Mo steel for power plant application, a trimetallic configuration using an insert piece (such as alloy 800) of intermediate thermal coefficient of expansion (CTE) has been sometimes suggested for bridging the wide gap in CTE between the two steels. Two joints are thus involved and this paper is concerned with the weld between 316LN and alloy 800. These welds were produced using three types of filler materials: austenitic stainless steels corresponding to 316,16Cr-8Ni-2Mo, and the nickel-base Inconel 182 1 . The weld fusion zones and the interfaces with the base materials were characterised in detail using light and transmission electron microscopy. The 316 and Inconel 182 weld metals solidified dendritically, while the 16-8-2(16%Cr-8%Ni-2%Mo) weld metal showed a predominantly cellular substructure. The Inconel weld metal contained a large number of inclusions when deposited from flux-coated electrodes, but was relatively inclusion-free under inert gas-shielded welding. Long-term elevated-temperature aging of the weld metals resulted in embrittling sigma phase precipitation in the austenitic stainless steel weld metals, but the nickel-base welds showed no visible precipitation, demonstrating their superior metallurgical stability for high-temperature service. (orig.)

  5. Numerical simulation of continuous cooling of a low alloy steel to predict microstructure and hardness

    International Nuclear Information System (INIS)

    Kakhki, M Eshraghi; Kermanpur, A; Golozar, M A

    2009-01-01

    In this work, a numerical model was developed to simulate the continuous cooling of a low alloy steel. In order to simulate the kinetics of diffusional phase transformations, the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation and additivity rule were employed, while a new model was applied for martensitic transformation. In addition, a novel approach was applied for computing the actual phase fractions in the multiphase steel. Effects of latent heat release during phase transformations, temperature and phase fractions on the variation of thermo-physical properties were considered. The developed numerical model was applied to simulate the cooling process during the Jominy end quench test as well as the quenching of a steel gear in water and oil. In this respect, precise models were used to simulate the complex boundary conditions in the Jominy test and a stainless steel probe was used for determining the heat transfer coefficients of quenching media by an inverse method. The present model was validated against cooling curve measurements, metallographic analysis and hardness tests. Good agreement was found between the experimental and simulation results. This model is able to simulate the continuous cooling and kinetics of phase transformation and to predict the final distribution of microstructures and hardness in low alloy steels

  6. Quantitative consideration for the tempering effect during multi-pass thermal cycle in HAZ of low-alloy steel

    International Nuclear Information System (INIS)

    Yu, Lina; Nakabayashi, Yuma; Saida, Kazuyoshi; Mochizuki, Masahito; Nishimoto, Kazutoshi; Kameyama, Masashi; Hirano, Shinro; Chigusa, Naoki

    2011-01-01

    A new Thermal Cycle Tempering Parameter (TCTP) to deal with the tempering effect during multi-pass thermal cycles has been proposed by extending Larson-Miller parameter (LMP). Experimental result revealed that the hardness in synthetic HAZ of the low alloy steel subjected to multi tempering thermal cycles has a good linear relationship with TCTP. By using this relationship, the hardness of the low-alloy steel reheated with tempering thermal cycles can be predicted when the original hardness is known. (author)

  7. Effects of the Microstructure on Segregation behavior of Ni-Cr-Mo High Strength Low Alloy RPV Steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Gyu; Wee, Dang Moon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Min Chul; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-10-15

    SA508 Gr.4N Ni-Cr-Mo low alloy steel has an improved fracture toughness and strength, compared to commercial Mn-Mo-Ni low alloy RPV steel SA508 Gr.3. Higher strength and fracture toughness of low alloy steels could be achieved by adding Ni and Cr. So there are several researches on SA508 Gr.4N low alloy steel for a RPV application. The operation temperature and time of a reactor pressure vessel is more than 300 .deg. C and over 40 years. Therefore, in order to apply the SA508 Gr.4N low alloy steel for a reactor pressure vessel, it requires a resistance of thermal embrittlement in the high temperature range including temper embrittlement resistance. S. Raoul reported that the susceptibility to temper embrittlement was increasing a function of the cooling rate in SA533 steel, which suggests the martensitic microstructures resulting from increased cooling rates are more susceptible to temper embrittlement. However, this result has not been proved yet. So the comparison of temper embrittlement behavior was made between martensitic microstructure and bainitic microstructure with a viewpoint of boundary features in SA508 Gr.4N, which have mixture of tempered bainite/martensite. In this study, we have compared temper embrittlement behaviors of SA508 Gr.4N low alloy steel with changing volume fraction of martensite. The mechanical properties of these low alloy steels) were evaluated after a long-term heat treatment(450 .deg. C, 2000hr. Then, the images of the segregated boundaries were observed and segregation behavior was analyzed by AES. In order to compare the misorientation distributions of model alloys, grain boundary structures were measured with EBSD

  8. Microstructures and properties of low-alloy fire resistant steel

    Indian Academy of Sciences (India)

    Unknown

    hardening. In a quenched and self-tempered 600 MPa class TMT reinforcement bar steel (YS: 624 MPa), low ..... of processing (1000–1050°C), static, dynamic as well as metadynamic recrystallization of austenite can occur (Poliak and Jonas ...

  9. Modeling the Gas Nitriding Process of Low Alloy Steels

    Science.gov (United States)

    Yang, M.; Zimmerman, C.; Donahue, D.; Sisson, R. D.

    2013-07-01

    The effort to simulate the nitriding process has been ongoing for the last 20 years. Most of the work has been done to simulate the nitriding process of pure iron. In the present work a series of experiments have been done to understand the effects of the nitriding process parameters such as the nitriding potential, temperature, and time as well as surface condition on the gas nitriding process for the steels. The compound layer growth model has been developed to simulate the nitriding process of AISI 4140 steel. In this paper the fundamentals of the model are presented and discussed including the kinetics of compound layer growth and the determination of the nitrogen diffusivity in the diffusion zone. The excellent agreements have been achieved for both as-washed and pre-oxided nitrided AISI 4140 between the experimental data and simulation results. The nitrogen diffusivity in the diffusion zone is determined to be constant and only depends on the nitriding temperature, which is ~5 × 10-9 cm2/s at 548 °C. It proves the concept of utilizing the compound layer growth model in other steels. The nitriding process of various steels can thus be modeled and predicted in the future.

  10. Viscosity and plasticity rise and reduction of anisotropy of low-alloy steel properties

    International Nuclear Information System (INIS)

    Matrosov, Yu.I.; Polyakov, I.E.

    1976-01-01

    Based on the published data, consideration is given to the possibilities of upgrading the toughness and plastic properties of low-alloy structural steels (16GS, 09G20S, 18G2, etc.) through the reduction in carbon and detrimental impurity (including sulphur) contents and also by treating the steels with the elements which are active with respect to sulphur (rare-earth metals, titanium, zirconium) and provide for the modifying action on sulphide inclusions. Drawing the impact strength properties on lateral samples nearer to those on longitudinal samples may be very favourable to the higher reliability of the structural components [ru

  11. Extractive-photometric determination of niobium with N-benzoylphenylhydroxylamine and lumogallion in alloyed steels

    International Nuclear Information System (INIS)

    Patratij, Yu.V.; Pilipenko, A.T.

    1978-01-01

    An extractive-photometric method has been developed to determine niobium (5) present as a heteroligand complex with N-benzoylphenylhydroxylamine (BPH) and lumogallion in alloyed steels. The method is based on preliminary extraction of niobium in a complex with BPH from concentrated HCl and subsequent determination of niobium in a 5-n (with respect to HCl) solution with lumogallion added. Sensitivity of the method is 2.0 μg of niobium in 10 ml of extract. The method has been tested on standard steels specimens

  12. Sulphide stress corrosion behaviour of a nickel coated high-strength low-alloyed steel

    Energy Technology Data Exchange (ETDEWEB)

    Salvago, G; Fumagalli, G; Cigada, A; Scolari, P

    1987-01-01

    The sulphide stress corrosion cracking (SSCC) of the quenched and tempered AISI 4137 H steel either bare or coated with nickel alloys was examined. Both traditional electrochemical and linear elastic fracture mechanics methods were used to examine cracking in the NACE environment and in environments simulating the geothermal fluids found in the area of Larderello in Italy. Some tests were carried out on a geothermal well in Ferrara. High nickel content coatings seem to increase the SSCC resistance of the AISI 4137-H steel. Galvanic couplings effects are possible factors responsible for the behaviour in SSCC.

  13. EVALUATION OF METHODS FOR ESTIMATING FATIGUE PROPERTIES APPLIED TO STAINLESS STEELS AND ALUMINUM ALLOYS

    Directory of Open Access Journals (Sweden)

    Taylor Mac Intyer Fonseca Junior

    2013-12-01

    Full Text Available This work evaluate seven estimation methods of fatigue properties applied to stainless steels and aluminum alloys. Experimental strain-life curves are compared to the estimations obtained by each method. After applying seven different estimation methods at 14 material conditions, it was found that fatigue life can be estimated with good accuracy only by the Bäumel-Seeger method for the martensitic stainless steel tempered between 300°C and 500°C. The differences between mechanical behavior during monotonic and cyclic loading are probably the reason for the absence of a reliable method for estimation of fatigue behavior from monotonic properties for a group of materials.

  14. Steeling and Resilience in Art Education

    Science.gov (United States)

    Heise, Donalyn

    2014-01-01

    Steel is an incredibly strong alloy of iron and carbon. Due to its incredible strength and durability, this resilient material is commonly used for constructing buildings. The transitive verb "steeling" is defined in Miriam-Webster dictionary as "to fill with resolution or determination, as in, she 'steeled herself to face the…

  15. A thermostatistical theory for solid solution effects in the hot deformation of alloys: an application to low-alloy steels

    International Nuclear Information System (INIS)

    Galindo-Nava, E I; Rivera-Díaz-del-Castillo, P E J; Perlade, A

    2014-01-01

    The hot deformation of low-alloy steels is described by a thermostatistical theory of plastic deformation. This is based on defining a statistical entropy term that accounts for the energy dissipation due to possible dislocation displacements. In this case, dilute substitutional and interstitial atom effects alter such paths. The dislocation population is described by a single parameter equation, with the parameter being the average dislocation density. Solute effects incorporate additional dislocation generation sources. They alter the energy barriers corresponding to the activation energies for dislocation recovery, grain nucleation and growth. The model is employed to describe work hardening and dynamic recrystallization softening in fifteen steels for a wide range of compositions, temperatures and strain rates. Maps for dynamic recrystallization occurrence are defined in terms of processing conditions and composition. (paper)

  16. Bonding tungsten, W–Cu-alloy and copper with amorphous Fe–W alloy transition

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song, E-mail: wangsongrain@163.com [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Ling, Yunhan, E-mail: yhling@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Zhao, Pei [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zang, Nanzhi [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Wang, Jianjun [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China); Guo, Shibin [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Jun [Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Xu, Guiying [Laboratory of Special Ceramics and Powder Metallurgy, University of Science and Technology Beijing, Beijing 100083 (China)

    2013-05-15

    W/Cu graded materials are the leading candidate materials used as the plasma facing components in a fusion reactor. However, tungsten and copper can hardly be jointed together due to their great differences in physical properties such as coefficient of thermal expansion and melting point, and the lack of solid solubility between them. To overcome those difficulties, a new amorphous Fe–W alloy transitional coating and vacuum hot pressing (VHP) method were proposed and introduced in this paper. The morphology, composition and structure of the amorphous Fe–W alloy coating and the sintering interface of the specimens were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The thermal shock resistance of the bonded composite was also tested. The results demonstrated that amorphous structure underwent change from amorphous to nano grains during joining process, and the joined W/Cu composite can endued plasma thermal shock resistance with energy density more than 5.33 MW/m{sup 2}. It provides a new feasible technical to join refractory tungsten to immiscible copper with amorphous Fe–W alloy coating.

  17. Mechanical properties and microstructure of copper alloys and copper alloy-stainless steel laminates for fusion reactor high heat flux applications

    Science.gov (United States)

    Leedy, Kevin Daniel

    A select group of copper alloys and bonded copper alloy-stainless steel panels are under consideration for heat sink applications in first wall and divertor structures of a planned thermonuclear fusion reactor. Because these materials must retain high strengths and withstand high heat fluxes, their material properties and microstructures must be well understood. Candidate copper alloys include precipitate strengthened CuNiBe and CuCrZr and dispersion strengthened Cu-Alsb2Osb3 (CuAl25). In this study, uniaxial mechanical fatigue tests were conducted on bulk copper alloy materials at temperatures up to 500sp°C in air and vacuum environments. Based on standardized mechanical properties measurement techniques, a series of tests were also implemented to characterize copper alloy-316L stainless steel joints produced by hot isostatic pressing or by explosive bonding. The correlation between mechanical properties and the microstructure of fatigued copper alloys and the interface of copper alloy-stainless steel laminates was examined. Commercial grades of these alloys were used to maintain a degree of standardization in the materials testing. The commercial alloys used were OMG Americas Glidcop CuAl25 and CuAl15; Brush Wellman Hycon 3HP and Trefimetaux CuNiBe; and Kabelmetal Elbrodur and Trefimetaux CuCrZr. CuAl25 and CuNiBe alloys possessed the best combination of fatigue resistance and microstructural stability. The CuAl25 alloy showed only minimal microstructural changes following fatigue while the CuNiBe alloy consistently exhibited the highest fatigue strength. Transmission electron microscopy observations revealed that small matrix grain sizes and high densities of submicron strengthening phases promoted homogeneous slip deformation in the copper alloys. Thus, highly organized fatigue dislocation structure formation, as commonly found in oxygen-free high conductivity Cu, was inhibited. A solid plate of CuAl25 alloy hot isostatically pressed to a 316L stainless steel

  18. Literature Survey on the Stress Corrosion Cracking of Low-Alloy Steels in High Temperature Water

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.P

    2002-02-01

    The present report is a summary of a literature survey on the stress corrosion cracking (SCC) behaviour/ mechanisms in low-alloy steels (LAS) in high-temperature water with special emphasis to primary-pressure-boundary components of boiling water reactors (BWR). A brief overview on the current state of knowledge concerning SCC of low-alloy reactor pressure vessel and piping steels under BWR conditions is given. After a short introduction on general aspects of SCC, the main influence parameter and available quantitative literature data concerning SCC of LAS in high-temperature water are discussed on a phenomenological basis followed by a summary of the most popular SCC models for this corrosion system. The BWR operating experience and service cracking incidents are discussed with respect to the existing laboratory data and background knowledge. Finally, the most important open questions and topics for further experimental investigations are outlined. (author)

  19. Remediation of phosphate-contaminated water by electrocoagulation with aluminium, aluminium alloy and mild steel anodes.

    Science.gov (United States)

    Vasudevan, Subramanyan; Lakshmi, Jothinathan; Jayaraj, Jeganathan; Sozhan, Ganapathy

    2009-05-30

    The present study provides an electrocoagulation process for the remediation of phosphate-contaminated water using aluminium, aluminium alloy and mild steel as the anodes and stainless steel as the cathode. The various parameters like effect of anode materials, effect of pH, concentration of phosphate, current density, temperature and co-existing ions, and so forth, and the adsorption capacity was evaluated using both Freundlich and Langmuir isotherm models. The adsorption of phosphate preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. The results showed that the maximum removal efficiency of 99% was achieved with aluminium alloy anode at a current density of 0.2 A dm(-2), at a pH of 7.0. The adsorption process follows second-order kinetics.

  20. Microstructural characterization of atom clusters in irradiated pressure vessel steels and model alloys

    International Nuclear Information System (INIS)

    Auger, P.; Pareige, P.; Akamatsu, M.; Van Duysen, J.C.

    1993-01-01

    In order to characterize the microstructural evolution of iron solid solution under irradiation, two pressure vessel steels irradiated in service conditions, and, for comparison, low copper model alloys irradiated with neutrons and electrons, have been studied through small angle neutron scattering and atom probe experiments. In Fe-Cu model alloys, copper clusters are formed containing uncertain proportions of iron. In the low copper industrial steels, the feature is more complex; solute atoms such as Ni, Mn and Si, sometimes associated with Cu, segregate as ''clouds'' more or less condensed in the iron solid solution. These silicides, or at least Si, Ni, Mn association, may facilitate the copper segregation although the initial iron matrix contains a low copper concentration. (authors). 24 refs., 3 figs., 2 tabs

  1. Evaluation of High Temperature Corrosion Resistance of Finned Tubes Made of Austenitic Steel And Nickel Alloys

    Directory of Open Access Journals (Sweden)

    Turowska A.

    2016-06-01

    Full Text Available The purpose of the paper was to evaluate the resistance to high temperature corrosion of laser welded joints of finned tubes made of austenitic steel (304,304H and nickel alloys (Inconel 600, Inconel 625. The scope of the paper covered the performance of corrosion resistance tests in the atmosphere of simulated exhaust gases of the following chemical composition: 0.2% HCl, 0.08% SO2, 9.0% O2 and N2 in the temperature of 800°C for 1000 hours. One found out that both tubes made of austenitic steel and those made of nickel alloy displayed good resistance to corrosion and could be applied in the energy industry.

  2. Investigation of attenuation coefficients of some stainless steel and aluminum alloys

    Science.gov (United States)

    Caner, Zafer; Tufan, Mustafa ćaǧatay

    2018-02-01

    In this study, attenuation coefficients of two different stainless steel alloys (AISI 304 and AISI 310), which have a wide range of applications from home appliances to the automotive sector, and two different aluminum alloys (6013 and 5083), which have a high mechanical strength and a light weight structure and are used in many fields from aviation to military vehicles, has been determined. For this purpose, we used gamma spectrometer system with NaI(Tl) detector. In our measurements, we used Eu-152, Ra-226 and Co-60 as gamma ray sources. To narrow the beam of gamma rays, we designed the new steel based collimator. We also investigated the effect of using collimator. Obtained results were compared with the NIST XCOM values.

  3. High strength H2S resistant steels and alloys for oil field tubular products

    International Nuclear Information System (INIS)

    Straatmann, J.A.; Grobner, P.J.

    1976-01-01

    New sources of oil and natural gas are more frequently occurring at greater depths in hostile surface and underground environments. The materials utilized in drilling and completing the wells require higher strength along with improved resistance to corrosive/embrittling attack by contaminants present in the deep, high pressure-high temperature formations. Higher strength steels having yield strengths in excess of 690 MPa and possessing improved resistance to sulfide stress corrosion cracking (SSC) have been developed and are currently being evaluated by the oil industry. The research to develop these new steels combined modifications of chemical compositions, heat treatment and processing variables. For most severe SSC environments and deep wells, it was necessary to provide even better alloys for tubular materials. The successful solution to the problem was found with the utilization of nickel-base alloys. These materials are being evaluated in commercial applications

  4. Corrosion life-time assessment of carbon steel and stainless alloys for geological disposal facility

    International Nuclear Information System (INIS)

    Kosaki, Akio; Komada, Hiroya

    1993-01-01

    The disposal facility for radioactive wastes requires long-term integrity. Metal is being considered for use as the engineered barrier which constructs the outer walls in such a facility, in order to prevent groundwater percolation. Thus, the most important problem for the integrity of the engineered barrier is corrosion by groundwater. There are two ways for using metal as an engineered barrier; one is as a structural material; and the other is as the inner-lining material of a concrete wall. This report discusses the corrosion lifetime assessment of carbon steel used as a structural and lining material, and stainless alloys, Type 304 steel and Titanium alloys used as lining materials. Corrosion potential and crevice corrosion are measured in the environment of neutral and alkalized water

  5. The influence of deep cryogenic treatment on the properties of high-vanadium alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haizhi [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Tong, Weiping, E-mail: wptong@mail.neu.edu.cn [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Cui, Junjun [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Zhang, Hui [Key Laboratory of Electromagnetic Processing of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Chen, Liqing [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Zuo, Liang [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang 110819 (China)

    2016-04-26

    Deep cryogenic treatment can improve the mechanical properties of many metallic materials, but there are few reports of the effect of deep cryogenic treatment on high-vanadium alloy steel. The main objective of this work is to investigate the effect of deep cryogenic treatment on the microstructure, hardness, impact toughness and abrasive wear resistance of high-vanadium alloy steel. The results show that large amounts of small secondary carbide precipitation after deep cryogenic treatment and microcracks were detected and occurred preferentially at carbide/matrix interfaces; except for the hardness, the mechanical properties increased compared to those of the conventional treatment sample. By increasing the deep cryogenic processing time and cycle number, impact toughness and abrasive wear resistance can be further improved, the carbide contents continuously increase, and the hardness decreases.

  6. Corrosion Fatigue Characteristics of 12Cr Alloy Steel in Na2SO4 Solution

    Science.gov (United States)

    Bae, D. H.; Cho, S. Y.

    In order to estimate reliability of 12Cr alloy steel using as the turbine blade material of the steam power plant, its corrosion fatigue characteristics in Na2SO4 solution considering its percentage and temperature that were determined from the polarization test results were investigated, and compared with the results in air. The corrosion characteristic of 12Cr alloy steel was remarkably susceptible in 12.7wt.% (IM) Na2SO4 solution, and its susceptibility increased with the solution temperature increase. The corrosion fatigue characteristics in 12.7wt.% Na2SO4 solution were similar to that of in air at 25°C. The crack growth rate was however increased with the temperature of solution increase. The reasons showing such results are due to the difference of the crack growth mechanism according to the electro-chemical activity of the corrosion factors.

  7. Microstructural characterization of atom clusters in irradiated pressure vessel steels and model alloys

    Energy Technology Data Exchange (ETDEWEB)

    Auger, P; Pareige, P [Rouen Univ., 76 - Mont-Saint-Aignan (France); Akamatsu, M; Van Duysen, J C [Electricite de France (EDF), 77 - Ecuelles (France)

    1994-12-31

    In order to characterize the microstructural evolution of iron solid solution under irradiation, two pressure vessel steels irradiated in service conditions, and, for comparison, low copper model alloys irradiated with neutrons and electrons, have been studied through small angle neutron scattering and atom probe experiments. In Fe-Cu model alloys, copper clusters are formed containing uncertain proportions of iron. In the low copper industrial steels, the feature is more complex; solute atoms such as Ni, Mn and Si, sometimes associated with Cu, segregate as ``clouds`` more or less condensed in the iron solid solution. These silicides, or at least Si, Ni, Mn association, may facilitate the copper segregation although the initial iron matrix contains a low copper concentration. (authors). 24 refs., 3 figs., 2 tabs.

  8. Alloying effect on the structure and properties of austenitic heat-resistant steels

    International Nuclear Information System (INIS)

    Levitin, V.V.; Grabovskij, V.Ya.; Korostelev, V.F.; Ryvkin, Yu.A.

    1978-01-01

    Investigated have been mechanical properties at test temperatures of 20-95O deg C, wear resistance, softening at thermomechanical cycling and microstructure of cast austenitic chromium-nickel steels (13%Cr + 35%Ni), produced by electroslag remelting with variations in Ti, Mo, Nb and W contents. Regression equations for relationship of the investigated characteristics to alloying element content have been obtained. Titanium, molybdenum and niobium increasing hardness and strength limit at room and high temperatures promote a decrease in ductility. Tungsten increases strength properties, wear resistance and thermal stability of the steels without negative effect on the impact strength. The impact strength decrease with an increase in alloying is due to brittle precipitations along the boundaries of as-cast grains, containing Ti, Mo, Nb and Si

  9. Fouling and biocorrosion of a high-alloy steel in the Golden Horn bay

    International Nuclear Information System (INIS)

    Koryakova, M.D.; Nikitin, V.M.; Suponina, A.P.; Kharchenko, U.V.; Zvyagintsev, A.Yu.

    2002-01-01

    The studies on the effect of contamination of the Golden Horn bay waters (the Peter the Great Bay in the Japanese Sea) on formation of the community of the bacterio- and macrofouling and corrosion resistance of the Kh18N10T high-alloy steel are continued. The dissolved and chemically absorbed oxygen, pH, saprophytes, oil-oxidizing, sulfate-reducing bacteria and heavy metals are among the medium indicators, characterizing the level of pollution of the regions of the samples testing. It is shown, that the obtained experimental data extend our understanding of the dependent effect of three factors: the sea medium → fouling → corrosion resistance of the Kh18N10T high-alloy steel [ru

  10. Characterization of atom clusters in irradiated pressure vessel steels and model alloys

    International Nuclear Information System (INIS)

    Auger, P.; Pareige, P.; Akamatsu, M.; Van Duysen, J.C.

    1993-12-01

    In order to characterize the microstructural evolution of the iron solid solution under irradiation, two pressure vessel steels irradiated in service conditions and, for comparison, low copper model alloys irradiated with neutrons and electrons have been studied. The characterization has been carried out mainly thanks to small angle neutron scattering and atom probe experiments. Both techniques lead to the conclusion that clusters develop with irradiations. In Fe-Cu model alloys, copper clusters are formed containing uncertain proportions of iron. In the low copper industrial steels, the feature is more complex. Solute atoms like Ni, Mn and Si, sometimes associated with Cu, segregate as ''clouds'' more or less condensed in the iron solid solution. These silicides, or at least Si, Ni, Mn association, may facilitate the copper segregation although the initial iron matrix contains a low copper concentration. (authors). 24 refs., 3 figs., 2 tabs

  11. Corrosion studies on Cu-Ni alloys and ferritic steel in salt water for desalination service

    International Nuclear Information System (INIS)

    Shibad, P.R.; Balachandra, J.

    1975-01-01

    Corrosion studies on In 838 and In 848 alloys in 3% NaCl solution, synthetic sea water and in 3% NaCl at pH3 and pH10 indicate that the latter alloy is more corrosion resistant than the former at room (28 0 C), and boiling temperature (101 0 C) and at 125 0 C. Ferritic steel is unaffected in boiling synthetic sea water. In boiling 3% NaCl solution at pH3 and pH10, (the pH values adjusted at room temperature) increase in the rate of corrosion of ferritic steel compared to that at room temperature has been observed. A fair correlation between polarization characteristics and dissolution rates in these solutions is seen for all these materials. (author)

  12. Microstructural Characterization of Clad Interface in Welds of Ni-Cr-Mo High Strength Low Alloy Steel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong-Eun; Kim, Min-Chul; Lee, Ho-Jin; Kim, Keong-Ho [KAERI, Daejeon (Korea, Republic of); Lee, Ki-Hyoung [KAIST, Daejeon (Korea, Republic of); Lee, Chang-Hee [Hanyang Univ., Seoul (Korea, Republic of)

    2011-08-15

    SA508 Gr.4N Ni-Cr-Mo low alloy steel, in which Ni and Cr contents are higher than in commercial SA508 Gr.3 Mn-Mo-Ni low alloy steels, may be a candidate reactor pressure vessel (RPV) material with higher strength and toughness from its tempered martensitic microstructure. The inner surface of the RPV is weld-cladded with stainless steels to prevent corrosion. The goal of this study is to evaluate the microstructural properties of the clad interface between Ni-Cr-Mo low alloy steel and stainless weldment, and the effects of post weld heat treatment (PWHT) on the properties. The properties of the clad interface were compared with those of commercial Mn-Mo-Ni low alloy steel. Multi-layer welding of model alloys with ER308L and ER309L stainless steel by the SAW method was performed, and then PWHT was conducted at 610°C for 30 h. The microstructural changes of the clad interface were analyzed using OM, SEM and TEM, and micro-Vickers hardness tests were performed. Before PWHT, the heat affected zone (HAZ) showed higher hardness than base and weld metals due to formation of martensite after welding in both steels. In addition, the hardness of the HAZ in Ni-Cr-Mo low alloy steel was higher than that in Mn-Mo-Ni low alloy steel due to a comparatively high martensite fraction. The hardness of the HAZ decreased after PWHT in both steels, but the dark region was formed near the fusion line in which the hardness was locally high. In the case of Mn-Mo-Ni low alloy steel, formation of fine Cr-carbides in the weld region near the fusion line by diffusion of C from the base metal resulted in locally high hardness in the dark region. However, the precipitates of the region in the Ni-Cr-Mo low alloy steel were similar to that in the base metal, and the hardness in the region was not greatly different from that in the base metal.

  13. Microstructural Characterization of Clad Interface in Welds of Ni-Cr-Mo High Strength Low Alloy Steel

    International Nuclear Information System (INIS)

    Kim, Hong-Eun; Kim, Min-Chul; Lee, Ho-Jin; Kim, Keong-Ho; Lee, Ki-Hyoung; Lee, Chang-Hee

    2011-01-01

    SA508 Gr.4N Ni-Cr-Mo low alloy steel, in which Ni and Cr contents are higher than in commercial SA508 Gr.3 Mn-Mo-Ni low alloy steels, may be a candidate reactor pressure vessel (RPV) material with higher strength and toughness from its tempered martensitic microstructure. The inner surface of the RPV is weld-cladded with stainless steels to prevent corrosion. The goal of this study is to evaluate the microstructural properties of the clad interface between Ni-Cr-Mo low alloy steel and stainless weldment, and the effects of post weld heat treatment (PWHT) on the properties. The properties of the clad interface were compared with those of commercial Mn-Mo-Ni low alloy steel. Multi-layer welding of model alloys with ER308L and ER309L stainless steel by the SAW method was performed, and then PWHT was conducted at 610°C for 30 h. The microstructural changes of the clad interface were analyzed using OM, SEM and TEM, and micro-Vickers hardness tests were performed. Before PWHT, the heat affected zone (HAZ) showed higher hardness than base and weld metals due to formation of martensite after welding in both steels. In addition, the hardness of the HAZ in Ni-Cr-Mo low alloy steel was higher than that in Mn-Mo-Ni low alloy steel due to a comparatively high martensite fraction. The hardness of the HAZ decreased after PWHT in both steels, but the dark region was formed near the fusion line in which the hardness was locally high. In the case of Mn-Mo-Ni low alloy steel, formation of fine Cr-carbides in the weld region near the fusion line by diffusion of C from the base metal resulted in locally high hardness in the dark region. However, the precipitates of the region in the Ni-Cr-Mo low alloy steel were similar to that in the base metal, and the hardness in the region was not greatly different from that in the base metal.

  14. Corrosion Characterization in Nickel Plated 110 ksi Low Alloy Steel and Incoloy 925: An Experimental Case Study

    Science.gov (United States)

    Thomas, Kiran; Vincent, S.; Barbadikar, Dipika; Kumar, Shresh; Anwar, Rebin; Fernandes, Nevil

    2018-04-01

    Incoloy 925 is an age hardenable Nickel-Iron-Chromium alloy with the addition of Molybdenum, Copper, Titanium and Aluminium used in many applications in oil and gas industry. Nickel alloys are preferred mostly in corrosive environments where there is high concentration of H2S, CO2, chlorides and free Sulphur as sufficient nickel content provides protection against chloride-ion stress-corrosion cracking. But unfortunately, Nickel alloys are very expensive. Plating an alloy steel part with nickel would cost much lesser than a part make of nickel alloy for large quantities. A brief study will be carried out to compare the performance of nickel plated alloy steel with that of an Incoloy 925 part by conducting corrosion tests. Tests will be carried out using different coating thicknesses of Nickel on low alloy steel in 0.1 M NaCl solution and results will be verified. From the test results we can confirm that Nickel plated low alloy steel is found to exhibit fairly good corrosion in comparison with Incoloy 925 and thus can be an excellent candidate to replace Incoloy materials.

  15. 77 FR 73015 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2012-12-07

    ... Steel Pipe From the Republic of Korea: Preliminary Results of Antidumping Duty Administrative Review... antidumping duty order on circular welded non-alloy steel pipe (CWP) from the Republic of Korea (Korea). The... preliminarily found that one respondent has made sales of the subject merchandise at prices below normal value...

  16. Effect Mo Addition on Corrosion Property and Sulfide Stress Cracking Susceptibility of High Strength Low Alloy Steels

    International Nuclear Information System (INIS)

    Lee, Woo Yong; Koh, Seong Ung; Kim, Kyoo Young

    2005-01-01

    The purpose of this work is to understand the effect of Mo addition on SSC susceptibility of high strength low alloy steels in terms of microstructure and corrosion property. Materials used in this study are high strength low alloy (HSLA) steels with carbon content of 0.04wt% and Mo content varying from 0.1 to 0.3wt%. The corrosion property of steels was evaluated by immersion test in NACE-TM01-77 solution A and by analyzing the growth behavior of surface corrosion products. SSC resistance of steels was evaluated using constant load test. Electrochemical test was performed to investigate initial corrosion rate. Addition of Mo increased corrosion rate of steels by enhancing the porosity of surface corrosion products. however, corrosion rate was not directly related to SSC susceptibility of steels

  17. Study of a low alloy steel rust using Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Maier, I.A.; Saragovi-Badler, C.; Labenski, F.

    1978-01-01

    Moessbauer spectroscopy has been used to analyze the internal and external rust layers of a weathering steel exposed for ten months to an urban-industrial atmosphere. Superparamagnetic α-FeOOH and γ-FeOOH were found in both layers. The external one also contained small sized delta-FeOOH and/or amorphous iron oxyhydroxide. These compounds were not present in the internal layer at this stage of the patina formation. (author)

  18. Crack growth behavior of low-alloy bainitic 51CrV4 steel

    OpenAIRE

    Canadinç, Demircan; Lambers, H. G.; Gorny B.; Tschumak, S.; Maier, H.J.

    2010-01-01

    The crack growth behavior of low-alloy bainitic 51CrV4 steel was investigated. The current results indicate that the stress state present during the isothermal bainitic transformation has a strong influence on the crack propagation behavior in the near threshold regime, when the crack growth direction is perpendicular to the loading axis of the original sample undergoing phase transformation. However, the influence of stresses superimposed during the bainitic transformation on the crack growt...

  19. Fracture toughness of welded joints of a high strength low alloy steel

    International Nuclear Information System (INIS)

    Veiga, S.M.B. da; Bastian, F.L.; Pope, A.M.

    1985-10-01

    The fracture toughness of the different regions of welded joints of a high strength low alloy steel, Niocor 2, was evaluated at different temperatures and compared with the toughness of the base metal. The studied regions were: the weld metal, fusion boundary and heat affected zone. The welding process used was the manual metal arc. It is shown that the weld metal region has the highest toughness values. (Author) [pt

  20. Welding of Nb micro-alloyed steel by the submerged arc process using Brazilian consumables

    International Nuclear Information System (INIS)

    Scotti, A.; Quites, A.M.

    1982-01-01

    A set of procedures was established for welding of Nb micro-alloyed steel by the submerged arc process, using national consumables, in order to simultaneously achieve a more economic welding and better mechanical properties. From all the wire-flux combinations the better were the correspondent to AWS F84ED1, F74EM12K and F84EH14, the last being the best. (Author) [pt

  1. Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

    Science.gov (United States)

    Wang, Jing; Lu, Min-xu; Zhang, Lei; Chang, Wei; Xu, Li-ning; Hu, Li-hua

    2012-06-01

    To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by energy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corrosion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG welding. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints produced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.

  2. Influence of alloying elements on the corrosion properties of shape memory stainless steels

    International Nuclear Information System (INIS)

    Della Rovere, C.A.; Alano, J.H.; Silva, R.; Nascente, P.A.P.; Otubo, J.; Kuri, S.E.

    2012-01-01

    Highlights: ► The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape-memory stainless steels (SMSSs) were compared with those of a type 304 (SS 304) austenitic stainless steel. ► A considerably high Si content (about 40 at%) is present in the anodic passive films formed on SMSSs in 0.5 M H 2 SO 4 solution. ► The high protectiveness of the anodic passive film formed on SMSSs in 0.5 M H 2 SO 4 solution results from a protective film consisting of a (Fe, Cr)–mixed silicate. ► The SMSSs exhibited higher corrosion resistance than SS 304 in highly oxidizing environments. ► The SMSSs showed poor corrosion resistance in 3.5% NaCl solution compared to that of SS 304. - Abstract: The corrosion properties of three Fe–Mn–Si–Cr–Ni–(Co) shape memory stainless steels were studied based on X-ray photoelectron spectroscopy (XPS) analyses, immersion and polarization tests. The test results were compared with those of a type 304 austenitic stainless steel. The XPS analyses indicated substantial Si content in the anodic passive films formed on shape memory stainless steels in sulfuric acid solution and that the high protectiveness of these films results from a protective film consisting of a (iron, chromium)–mixed silicate. The corrosion rate of the shape memory stainless steels in boiling nitric acid solution was lower than that of austenitic stainless steel. The high silicon content was found to play an important role in the corrosion behavior of these shape memory alloys in highly oxidizing environments. Due to their high manganese content, the shape memory stainless steels showed poor corrosion behavior in 3.5% sodium chloride solution when compared with austenitic stainless steel.

  3. A study on corrosion resistance of electrodeposited Zn-base alloy steel sheet

    International Nuclear Information System (INIS)

    Park, Hyun Soon

    1986-01-01

    Effects of electrodeposits of Zn-Ni or Zn-Co alloy with small amounts of Mo or W in sulphate bath on the corrosion resistance of plated steel sheet were studied. 1) The electrodeposition of Zn-Ni and Zn-Co alloy shows both anomalous codeposition behavior. The grade of anomalous codeposition of Zn-Co alloy rises with adding Mo or W in bath. 2) The Ni content in Zn-Ni deposits increases with decreasing cathode current density and with increasing bath temperature. 3) In case of electroplating of Zn-Co, the increase of cathodic current density of bath bring on increasing of the Co content, but on decreasing of the Mo content in deposits. And rising bath temperature increases both Co and Mo deposits. 4) The corrosion resistance of the Zn-Ni electrodeposited steel sheet is shown a maximum at the Ni content of 10-17%. The structure of Zn-Ni of these composition range was finegrained γ-phase. 5) The corrosion resistance of the Zn-Co electrodeposited steel sheet is improved with increasing Co content. The corrosion resistance of the Zn-Co-Mo or Zn-Co-W deposits electroplated by proper plating conditions was improved much more than that of Zn-Co deposits. (Author)

  4. Synthesis of electric discharge alloyed nickel–tungsten coating on tool steel and its tribological studies

    International Nuclear Information System (INIS)

    Arun, Ilangovan; Duraiselvam, Muthukannan; Senthilkumar, V.; Narayanasamy, R.; Anandakrishnan, V.

    2014-01-01

    Highlights: • Electrical discharge alloying/coating made on AISI D2 tool steel. • The hardness of EDA layer is three to four time higher than the base material. • The dry sliding wear tests performed on EDA layer at different temperatures. • The alloyed layer acts as a self-lubricant at higher temperature. - Abstract: The present study examines the method of depositing nickel and tungsten on die steel surface by means of dispersing these elements in dielectric fluid in an electrical discharge alloying (EDA) process. The modified surface was mechanically and metallurgically characterized using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX), microhardness tester and Pin-on-disc tribometer. The phase transformations that occurred during EDA process were evaluated by XRD. The deposition of Ni and W on die steel surfaces yielded minimal cracks with excellent metallurgical bonding. Higher hardness (∼1059 HV 0.3 ) with little brittleness resulted in superior wear resistance properties, a property which was retained even at elevated temperature

  5. X-ray photoelectron spectroscopy characterization of high dose carbon-implanted steel and titanium alloys

    Science.gov (United States)

    Viviente, J. L.; García, A.; Alonso, F.; Braceras, I.; Oñate, J. I.

    1999-04-01

    A study has been made of the depth dependence of the atomic fraction and chemical bonding states of AISI 440C martensitic stainless steel and Ti-6Al-4V alloy implanted with 75 keV C + at very high doses (above 10 18 ions cm -2), by means of X-ray photoelectron spectroscopy combined with an Ar + sputtering. A Gaussian-like carbon distribution was observed on both materials at the lowest implanted dose. More trapezoidal carbon depth-profiles were found with increasing implanted doses, and a pure carbon layer was observed only on the titanium alloy implanted at the highest dose. The implanted carbon was combined with both base metal and carbon itself to form metallic carbides and graphitic carbon. Furthermore, carbon-enriched carbides were also found by curve fitting the C 1s spectra. The titanium alloy showed a higher carbidic contribution than the steel implanted at the same C + doses. A critical carbon concentrations of about 33 at.% and 23 at.% were measured for the formation of C-C bonds in Ti-6Al-4V and steel samples, respectively. The carbon atoms were bound with metal to form carbidic compounds until these critical concentrations were reached; when this C concentration was exceeded the proportion of C-C bonds increased and resulted in the growth of carbonaceous layers.

  6. Influence of Cyclic Straining on Fatigue, Deformation, and Fracture Behavior of High-Strength Alloy Steel

    Science.gov (United States)

    Manigandan, K.; Srivatsan, T. S.; Vasudevan, V. K.; Tammana, D.; Poorganji, B.

    2016-01-01

    In this paper, the results of a study on microstructural influences on mechanical behavior of the high-strength alloy steel Tenax™ 310 are presented and discussed. Under the influence of fully reversed strain cycling, the stress response of this alloy steel revealed softening from the onset of deformation. Cyclic strain resistance exhibited a linear trend for the variation of both elastic strain amplitude with reversals-to-failure, and plastic strain amplitude with reversals-to-failure. Fracture morphology was essentially the same at the macroscopic level over the entire range of cyclic strain amplitudes examined. However, at the fine microscopic level, this high-strength alloy steel revealed fracture to be mixed-mode with features reminiscent of "locally" ductile and brittle mechanisms. The macroscopic mechanisms governing stress response at the fine microscopic level, resultant fatigue life, and final fracture behavior are presented and discussed in light of the mutually interactive influences of intrinsic microstructural effects, deformation characteristics of the microstructural constituents during fully reversed strain cycling, cyclic strain amplitude, and resultant response stress.

  7. Formation Energies and Electronic Properties of Vanadium Carbides Found in High Strength Steel Alloys

    Science.gov (United States)

    Limmer, Krista; Medvedeva, Julia

    2013-03-01

    Carbide formation and stabilization in steels is of great interest owing to its effect on the microstructure and properties of the Fe-based alloys. The appearance of carbides with different metal/C ratios strongly depends on the carbon concentration, alloy composition as well as the heat treatment. Strong carbide-forming elements such as Ti, V, and Nb have been used in microalloyed steels; with VC showing an increased solubility in the iron matrix as compared with TiC and NbC. This allows for dissolution of the VC into the steel during heating and fine precipitation during cooling. In addition to VC, the primary vanadium carbide with cubic structure, a wide range of non-stoichiometric compositions VCy with y varying from 0.72 to 0.88, has been observed. This range includes two ordered compounds, V8C7 and V6C5. In this study, first-principles density functional theory (DFT) is employed to examine the stability of the binary carbides by calculating their formation energies. We compare the local structures (atomic coordination, bond distances and angles) and the density of states in optimized geometries of the carbides. Further, the effect of alloying additions, such as niobium and titanium, on the carbide stabilization is investigated. We determine the energetically preferable substitutional atom location in each carbide and study the impurity distribution as well as its role in the carbide formation energy and electronic structure.

  8. Influence of MAO Treatment on the Galvanic Corrosion Between Aluminum Alloy and 316L Steel

    Science.gov (United States)

    Yang, Yuanhang; Gu, Yanhong; Zhang, Lei; Jiao, Xiangdong; Che, Juntie

    2017-12-01

    To slow down the galvanic corrosion of aluminum alloy and 316L stainless steel in subsea water, a micro-arc oxidation (MAO) coating was prepared on the surface of the Al alloy, and no treatment was performed on the surface of the 316L. The surface morphology of MAO-coated Al alloy was evaluated using a scanning electron microscope (SEM) before and after corrosion. A micro-hardness tester was used to measure the micro-hardness. Corrosion behaviors were evaluated by open-circuit potential (OCP), potentiodynamic polarization (PDP) and electrode impedance spectroscopy (EIS) tests in a 3.5 g/L NaCl solution. The results of PDP testing show that the corrosion potential of the MAO-coated galvanic pair was more positive than that of the uncoated galvanic pair and that the corrosion current density was smaller than that of the uncoated galvanic pair. EIS results show that the impedance of the galvanic pair increased after MAO coating. SEM images show that the corrosion damage of the uncoated Al alloy was more severe than that of the MAO-coated one, and the post-corrosion images of the surface of the 316L connected with MAO-coated Al alloy were more compact than those of the 316L connected with uncoated Al alloy. A physical model was developed to discuss the influence of MAO treatment on the galvanic corrosion process and corrosion mechanism.

  9. Effects of solute elements on irradiation hardening and microstructural evolution in low alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Katsuhiko, E-mail: fujiik@inss.co.jp [Institute of Nuclear Safety System Inc., 64 Sata, Mihama 919-1205 (Japan); Ohkubo, Tadakatsu, E-mail: OHKUBO.Tadakatsu@nims.go.jp [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Fukuya, Koji, E-mail: fukuya@inss.co.jp [Institute of Nuclear Safety System Inc., 64 Sata, Mihama 919-1205 (Japan)

    2011-10-01

    The effects of the elements Mn, Ni, Si and Cu on irradiation hardening and microstructural evolution in low alloy steels were investigated in ion irradiation experiments using five kinds of alloys prepared by removing Mn, Ni and Si from, and adding 0.05 wt.%Cu to, the base alloy (Fe-1.5Mn-0.5Ni-0.25Si). The alloy without Mn showed less hardening and the alloys without Ni or Si showed more hardening. The addition of Cu had hardly any influence on hardening. These facts indicated that Mn enhanced hardening and that Ni and Si had some synergetic effects. The formation of solute clusters was not confirmed by atom probe (AP) analysis, whereas small dislocation loops were identified by TEM observation. The difference in hardening between the alloys with and without Mn was qualitatively consistent with loop formation. However, microstructural components that were not detected by the AP and TEM were assumed to explain the hardening level quantitatively.

  10. Review of corrosion phenomena on zirconium alloys, niobium, titanium, inconel, stainless steel, and nickel plate under irradiation

    International Nuclear Information System (INIS)

    Johnson, A.B. Jr.

    1975-01-01

    The role of nuclear fluxes in corrosion processes was investigated in ATR, ETR, PRTR, and in Hanford production reactors. Major effort was directed to zirconium alloy corrosion parameter studies. Corrosion and hydriding results are reported as a function of oxygen concentration in the coolant, flux level, alloy composition, surface pretreatment, and metallurgical condition. Localized corrosion and hydriding at sites of bonding to dissimilar metals are described. Corrosion behavior on specimens transferred from oxygenated to low-oxygen coolants in ETR and ATR experiments is compared. Mechanism studies suggest that a depression in the corrosion of the Zr--2.5Nb alloy under irradiation is due to radiation-induced aging. The radiation-induced onset of transition on several alloys is in general a gradual process which nucleates locally, causing areas of oxide prosity which eventually encompass the surface. Examination of Zry-2 process tubes reveals that accelerated corrosion has occurred in low-oxygen coolants. Hydrogen contents are relatively low, but show some localized profiles. Gross hydriding has occurred on process tubes containing aluminum spacers, apparently by a galvanic charging mechanism. Titanium paralleled Zry-2 in corrosion behavior under irradiation. Niobium corrosion was variable, but did not appear to be strongly influenced by radiation. Corrosion rates on Inconel and stainless steel were only slightly higher in-flux than out-of-reactor. Corrosion rates on nickel-plated aluminum appeared to vary substantially with preexposure treatments, but the rates generally were accelerated compared to rates on unirradiated coupons. (59 references, 11 tables, 12 figs.)

  11. Diode Laser Welding/Brazing of Aluminum Alloy to Steel Using a Nickel Coating

    Directory of Open Access Journals (Sweden)

    Jin Yang

    2018-06-01

    Full Text Available Joining Al alloy to steel is of great interest for application in the automotive industry. Although a vast number of studies have been conducted to join Al to steel, the joining of Al to steel is still challenging due to the formation of brittle Fe–Al intermetallic compounds. In this work, the microstructure and mechanical properties of the dissimilar Al/steel joints with and without a nickel coating are comparatively investigated. A homogenous reaction layer composed of FeZn10 and Fe2Al5 is formed at the interface in the joints without Ni coating, and the joint facture load is only 743 N. To prevent the formation of brittle Fe2Al5, Ni electroplated coating is applied onto a steel surface. It has been shown that a nonhomogeneous reaction layer is observed at the interfacial region: Ni5Zn21 is formed at the direct irradiation zone, while Al3Ni is formed at the fusion zone root. The microhardness of the interfacial layer is reduced, which leads to the improvement of the joint mechanical properties. The average fracture load of the Al/Ni-coated steel joints reaches 930 N. In all of the cases, failure occurs at the Ni coating/fusion zone interface.

  12. Enhanced hot ductility of a Cr–Mo low alloy steel by rare earth cerium

    International Nuclear Information System (INIS)

    Jiang, X.; Song, S.-H.

    2014-01-01

    The hot ductility of a 1Cr–0.5Mo low alloy steel is investigated over a temperature range of 700–1050 °C using a Gleeble thermomechanical simulator in conjunction with various characterization techniques. The steel samples undoped and doped with cerium are heated at 1300 °C for 3 min and then cooled with a rate of 5 K s −1 down to different test temperatures, followed by tensile deformation until fracture. The results show that the hot ductility of the steel, evaluated by the reduction in area, can be substantially enhanced by a minor addition of cerium, especially in the range 800–1000 °C. In the austenite–ferrite dual-phase region, cerium may delay the formation of proeutectoid ferrite layers along austenite grain boundaries, thereby increasing the hot ductility of the steel. In the single austenite region, grain boundary segregation of cerium may increase the grain boundary cohesion, toughening the steel and thus raising the resistance to grain boundary sliding as well as promoting dynamic recrystallization. Consequently, the hot ductility of the steel is enhanced

  13. Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys

    Directory of Open Access Journals (Sweden)

    Masafumi Matsushita

    2011-07-01

    Full Text Available Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.

  14. Effect of structure and alloying elements on void formation in austenitic steels and nickel alloys

    International Nuclear Information System (INIS)

    Levy, V.; Azam, N.; Le Naour, L.; Didout, G.; Delaplace, J.

    1977-01-01

    In the development of the fast breeder reactors the phenomenon of metal swelling due to the formation of radiation induced voids is a large problem. In the complex alloys small fluctuations in composition can have a considerable effect on swelling and a great deal of investigation on the effect of both major and minor alloying elements is needed to be able to predict swelling. To provide more insight a research program involving irradiation of both commercial or specially cast alloys by 500 keV Ni + ions or 1 MeV electrons has been developed. The major results are presented

  15. Mechanical and wear properties of pre-alloyed molybdenum P/M steels with nickel addition

    Directory of Open Access Journals (Sweden)

    Yamanoglu R.

    2012-01-01

    Full Text Available The aim of this study is to understand the effect of nickel addition on mechanical and wear properties of molybdenum and copper alloyed P/M steel. Specimens with three different nickel contents were pressed under 400 MPa and sintered at 1120ºC for 30 minutes then rapidly cooled. Microstructures and mechanical properties (bending strength, hardness and wear properties of the sintered specimens were investigated in detail. Metallographical investigations showed that the microstructures of consolidated specimens consist of tempered martensite, bainite, retained austenite and pores. It is also reported that the amount of pores varies depending on the nickel concentration of the alloys. Hardness of the alloys increases with increasing nickel content. Specimens containing 2% nickel showed minimum pore quantity and maximum wear resistance. The wear mechanism changed from abrasive wear at low nickel content to adhesive wear at higher nickel content.

  16. Effect of Mn Content and Solution Annealing Temperature on the Corrosion Resistance of Stainless Steel Alloys

    Directory of Open Access Journals (Sweden)

    Ihsan-ul-Haq Toor

    2014-01-01

    Full Text Available The corrosion behavior of two specially designed austenitic stainless steels (SSs having different Nickel (Ni and Manganese (Mn contents was investigated. Prior to electrochemical tests, SS alloys were solution-annealed at two different temperatures, that is, at 1030°C for 2 h and 1050°C for 0.5 h. Potentiodynamic polarization (PD tests were carried out in chloride and acidic chloride, whereas linear polarization resistance (LPR and electrochemical impedance spectroscopy (EIS was performed in 0.5 M NaCl solution at room temperature. SEM/EDS investigations were carried out to study the microstructure and types of inclusions present in these alloys. Experimental results suggested that the alloy with highest Ni content and annealed at 1050°C/0.5 hr has the highest corrosion resistance.

  17. Characterization of the Interface of an Alloy 625 Overlay on Steels Using Nanoindentation

    Science.gov (United States)

    Dai, Tao; Lippold, John

    2018-06-01

    Industry standards require postweld heat treatment (PWHT) to reduce the heat-affected zone hardness of steels such as F22 (2.25Cr-1Mo) and AISI 8630 overlaid (clad) with Alloy 625 weld metal. PWHT results in carbon diffusion and accumulation at the interface between the steel and overlay. The accumulation of carbon in a planar solidification growth zone adjacent to the fusion boundary results in high hardness and the potential for hydrogen-assisted cracking. The planar growth zone (PGZ) is so narrow that normal Vickers hardness testing cannot fully reveal the hardness distribution in this zone. This study focused on the application of nanoindentation to characterize the hardness in the narrow microstructural regions adjacent to the fusion boundary. The development of nanohardness maps revealed that the PGZ is not necessarily the region that exhibits peak hardness after PWHT. The highest hardness values were associated with clusters of M7C3 carbides in specific subregions in the PGZ and also in the partially-mixed zone adjacent to the fusion boundary or in steel "swirl" structures. It was also confirmed in this study that nanohardness has a linear correlation with Vickers hardness values. The results presented here provide new insight into the role of carbon diffusion during PWHT and its effect on interface embrittlement associated with Alloy 625 overlays on steel.

  18. Microstructure and mechanical properties of a new type of austempered boron alloyed high silicon cast steel

    Directory of Open Access Journals (Sweden)

    Chen Xiang

    2013-05-01

    Full Text Available In the present paper, a new type of austempered boron alloyed high silicon cast steel has been developed, and its microstructures and mechanical properties at different temperatures were investigated. The experimental results indicate that the boron alloyed high silicon cast steel comprises a dendritic matrix and interdendritic eutectic borides in as-cast condition. The dendritic matrix is made up of pearlite, ferrite, and the interdendritic eutectic boride is with a chemical formula of M2B (M represents Fe, Cr, Mn or Mo which is much like that of carbide in high chromium white cast iron. Pure ausferrite structure that consists of bainitic ferrite and retained austenite can be obtained in the matrix by austempering treatment to the cast steel. No carbides precipitate in the ausferrite structure and the morphology of borides remains almost unchanged after austempering treatments. Secondary boride particles precipitate during the course of austenitizing. The hardness and tensile strength of the austempered cast steel decrease with the increase of the austempering temperature, from 250 篊 to 400 篊. The impact toughness is 4-11 J昪m-2 at room temperature and the impact fracture fractogragh indicates that the fracture is caused by the brittle fracture of the borides.

  19. Systematic investigation of the fatigue performance of a friction stir welded low alloy steel

    International Nuclear Information System (INIS)

    Toumpis, Athanasios; Galloway, Alexander; Molter, Lars; Polezhayeva, Helena

    2015-01-01

    Highlights: • The fatigue behaviour of a friction stir welded low alloy steel has been assessed. • The welds’ fatigue lives outperform the International Institute of Welding’s recommendations for fusion welds. • The slow weld exhibits the best fatigue performance of the investigated welds. • Fracture surface analysis shows that minor embedded flaws do not offer crack initiation sites. • Process-related surface breaking flaws have a significant effect on the fatigue life. - Abstract: A comprehensive fatigue performance assessment of friction stir welded DH36 steel has been undertaken to address the relevant knowledge gap for this process on low alloy steel. A detailed set of experimental procedures specific to friction stir welding has been put forward, and the consequent study extensively examined the weld microstructure and hardness in support of the tensile and fatigue testing. The effect of varying welding parameters was also investigated. Microstructural observations have been correlated to the weldments’ fatigue behaviour. The typical fatigue performance of friction stir welded steel plates has been established, exhibiting fatigue lives well above the weld detail class of the International Institute of Welding even for tests at 90% of yield strength, irrespective of minor instances of surface breaking flaws which have been identified. An understanding of the manner in which these flaws impact on the fatigue performance has been established, concluding that surface breaking irregularities such as these produced by the tool shoulder’s features on the weld top surface can be the dominant factor for crack initiation under fatigue loading

  20. Effect of surface decarburization on the mechanical properties of high strength low alloy steel

    International Nuclear Information System (INIS)

    Saqib, S.

    1993-01-01

    An attempt has been made to study the relationship of mechanical properties with the microstructure of a high strength low alloy steel. A thorough investigation was conducted on the steel sheet and variation in mechanical properties was observed across its thickness with a change in the microstructure. Change in hardness and tensile strength at the surface compare to the core of the material is attributed to decarburization. The current research indicates that the correlation between hardness and tensile strength is not valid for steels if the hardness is determined on the surface only. Great care should be taken at the time of determination of tensile strength by using conversion charts/tables on the basis of hardness values obtained by practical means. (author)

  1. Effect of Tryptophan on the corrosion behavior of low alloy steel in sulfamic acid

    Directory of Open Access Journals (Sweden)

    Hesham T.M. Abdel-Fatah

    2016-11-01

    Full Text Available Sulfamic acid is widely used in various industrial acid cleaning applications. In the present work, the inhibition effect of Tryptophan (Tryp on the corrosion of low alloy steel in sulfamic acid solutions at four different temperatures was studied. The investigations involved electrochemical methods (electrochemical impedance spectroscopy; EIS and the new technique electrochemical frequency modulation; EFM as well as gravimetric measurements. The inhibition efficiency and the apparent activation energy have been calculated in the presence and in the absence of Tryp. It is most probable that the inhibition property of Tryp was due to the electrostatic adsorption of the protonated form of Tryp on the steel surface. Adsorption of the inhibitor molecule, onto the steel surface followed the Temkin adsorption isotherm. The thermodynamic parameters of adsorption were determined and discussed. All of the obtained data from the three techniques were in close agreement, which confirmed that EFM technique can be used efficiently for monitoring the corrosion inhibition under the studied conditions.

  2. The measurement of phosphorus in low alloy steels by electrochemical methods

    International Nuclear Information System (INIS)

    Rahier, A.; Campsteyn, A.; Verheyen, E.; Verpoucke, G.

    2008-01-01

    The oscillo-polarographic method reported by Chen for the determination of phosphorus in silicates, iron ores, carbonates and tea leaves has been thoroughly studied and enhanced in view of the determination of P in various steels. Together with a carefully selected sample dissolution method, the chromatographic separation reported by Hanada et al. for eliminating the matrix has also been examined. The results of these investigations allowed finding out a path towards the successful electrochemical measurement of P in low alloy ferritic steels without eliminating the matrix. The limit of detection is 5.2 micro gram -1 in the metal. The precision ranges between 5 and 15 % relative to the mean measured values. The finely tuned method has been successfully validated using five NIST standard steels. The chromatographic method remains an option for addressing other metals in the future, should they contain unacceptable levels of possibly interfering elements.. Detailed experimental procedures are given.

  3. The measurement of phosphorus in low alloy steels by electrochemical methods

    Energy Technology Data Exchange (ETDEWEB)

    Rahier, A.; Campsteyn, A.; Verheyen, E.; Verpoucke, G.

    2008-08-15

    The oscillo-polarographic method reported by Chen for the determination of phosphorus in silicates, iron ores, carbonates and tea leaves has been thoroughly studied and enhanced in view of the determination of P in various steels. Together with a carefully selected sample dissolution method, the chromatographic separation reported by Hanada et al. for eliminating the matrix has also been examined. The results of these investigations allowed finding out a path towards the successful electrochemical measurement of P in low alloy ferritic steels without eliminating the matrix. The limit of detection is 5.2 micro gram{sup -1} in the metal. The precision ranges between 5 and 15 % relative to the mean measured values. The finely tuned method has been successfully validated using five NIST standard steels. The chromatographic method remains an option for addressing other metals in the future, should they contain unacceptable levels of possibly interfering elements.. Detailed experimental procedures are given.

  4. Compatibility of 316L stainless steel with the liquid alloy Pb17Li

    International Nuclear Information System (INIS)

    Broc, M.; Fauvet, P.; Flament, T.; Terlain, A.; Sannier, J.

    1988-01-01

    The behavior of 316L austenitic stainless steel in liquid eutectic lead alloy is investigated. The 316L is a possible structural material for fusion reactors. The obtained results are summarized and compared with other experimental data. The mechanisms which control the corrosion process are discussed. The investigation shows that whatever, the hydraulic flow, the corrosion of 316L stainless steel exposed to Pb17Li is characterized by the formation of a porous ferritic layer. The corrosion kinetics is mainly dependent on temperature, hydraulic flow and metallurgical state of the steel. At 400 0 C in turbulent flow, the corrosion rate at steady state of 316L solution annealed is estimated to 27 microns/year to which a depth of 25 microns has to be added to take into account the initial transient period. From overall available results, dissolution and solid state transformation in case of turbulent flow and diffusion in liquid phase for laminar flow, may be suggested

  5. Wetting Behavior of Molten AZ61 Magnesium Alloy on Two Different Steel Plates Under the Cold Metal Transfer Condition

    Directory of Open Access Journals (Sweden)

    ZENG Cheng-zong

    2017-04-01

    Full Text Available The wetting behavior and interfacial microstructures of molten magnesium AZ61 alloy on the surface of two different Q235 and galvanized steel plates under the condition of cold metal transfer were investigated by using dynamic sessile drop method. The results show that the wetting behavior is closely related to the wire feed speed. Al-Fe intermetallic layer was observed whether the substrate is Q235 steel or galvanized steel, and the formation of Al-Fe intermetallic layer should satisfy the thermodynamic condition of such Mg-Al/Fe system. The wettability of molten AZ61 magnesium alloy is improved with the increase of wire feed speed whether on Q235 steel surface or on galvanized steel surface, good wettability on Q235 steel surface is due to severe interface reaction when wire feed speed increases, good wettability on galvanized steel surface is attributed to the aggravating zinc volatilization. When the wire feed speed is ≤10.5m·min-1, the wettability of Mg alloy on Q235 steel plate is better than on galvanized steel plate. However, Zn vapor will result in instability for metal transfer process.

  6. Features of argon-arc welding of aluminium alloy AD1 to stainless steel 12Kh18N10T

    International Nuclear Information System (INIS)

    Sadov, I.I.

    1982-01-01

    Welding of pipes made of the 12Kh18N10T stainless steel and the AD1 aluminium alloy is proposed to perform using one-sided aluminizing. It is recommended to use shields in order to protect internal and external surfaces of pipes, aluminizing of which is impossible. It is shown that developed technological process for welded joints made of aluminium and stainless steel for cryogenic apparatus permits to create light-duty cryostat assembly using aluminium alloys instead of copper alloys, to increase reliability of apparatus (usage of welded joints instead of soldered ones), and to improve labour conditions

  7. Atom probe study of the microstructural evolution induced by irradiation in Fe-Cu ferritic alloys and pressure vessel steels

    International Nuclear Information System (INIS)

    Pareige, P.

    1996-04-01

    Pressure vessel steels used in pressurized water reactors are low alloyed ferritic steels. They may be prone to hardening and embrittlement under neutron irradiation. The changes in mechanical properties are generally supposed to result from the formation of point defects, dislocation loops, voids and/or copper rich clusters. However, the real nature of the irradiation induced-damage in these steels has not been clearly identified yet. In order to improve our vision of this damage, we have characterized the microstructure of several steels and model alloys irradiated with electrons and neutrons. The study was performed with conventional and tomographic atom probes. The well known importance of the effects of copper upon pressure vessel steel embrittlement has led us to study Fe-Cu binary alloys. We have considered chemical aging as well as aging under electron and neutron irradiations. The resulting effects depend on whether electron or neutron irradiations ar used for thus. We carried out both kinds of irradiation concurrently so as to compare their effects. We have more particularly considered alloys with a low copper supersaturation representative of that met with the French vessel alloys (0.1% Cu). Then, we have examined steels used on French nuclear reactor pressure vessels. To characterize the microstructure of CHOOZ A steel and its evolution when exposed to neutrons, we have studied samples from the reactor surveillance program. The results achieved, especially the characterization of neutron-induced defects have been compared with those for another steel from the surveillance program of Dampierre 2. All the experiment results obtained on model and industrial steels have allowed us to consider an explanation of the way how the defects appear and grow, and to propose reasons for their influence upon steel embrittlement. (author). 3 appends

  8. Neutron irradiation test of copper alloy/stainless steel joint materials

    International Nuclear Information System (INIS)

    Yamada, Hirokazu; Kawamura, Hiroshi

    2006-01-01

    As a study about the joint technology of copper alloy and stainless steel for utilization as cooling piping in International Thermonuclear Experimental Reactor (ITER), Al 2 O 3 -dispersed strengthened copper or CuCrZr was jointed to stainless steel by three kinds of joint methods (casting joint, brazing joint and friction welding method) for the evaluation of the neutron irradiation effect on joints. A neutron irradiation test was performed to three types of joints and each copper alloy. The average value of fast neutron fluence in this irradiation test was about 2 x 10 24 n/m 2 (E>1 MeV), and the irradiation temperature was about 130degC. As post-irradiation examinations, tensile tests, hardness tests and observation of fracture surface after the tensile tests were performed. All type joints changed to be brittle by the neutron irradiation effect like each copper alloy material, and no particular neutron irradiation effect due to the effect of joint process was observed. On the casting and friction welding, hardness of copper alloy near the joint boundary changed to be lower than that of each copper alloy by the effect of joint procedure. However, tensile strength of joints was almost the same as that of each copper alloy before/after neutron irradiation. On the other hand, tensile strength of joints by brazing changed to be much lower than CuAl-25 base material by the effect of joint process before/after neutron irradiation. Results in this study showed that the friction welding method and the casting would be able to apply to the joint method of piping in ITER. This report is based on the final report of the ITER Engineering Design Activities (EDA). (author)

  9. Internal stresses in steel plate generated by shape memory alloy inserts

    International Nuclear Information System (INIS)

    Malard, B.; Pilch, J.; Sittner, P.; Davydov, V.; Sedlák, P.; Konstantinidis, K.; Hughes, D.J.

    2012-01-01

    Graphical abstract: Display Omitted Highlights: ► Thermoresponsive internal stresses introduced into steel by embedding SMA inclusions. ► Neutron strain scanning on steel plate coupons with NiTi inserts at 21 °C and 130 °C. ► Internal stress field in steel evaluated directly from strains and by FE simulation. ► Internal stress generation by SMA insert resistant to thermal and mechanical fatigue. - Abstract: Neutron strain scanning was employed to investigate the internal stress fields in steel plate coupons with embedded prestrained superelastic NiTi shape memory alloy inserts. Strain fields in steel were evaluated at T = 21 °C and 130 °C on virgin coupons as well as on mechanically and thermally fatigued coupons. Internal stress fields were evaluated by direct calculation of principal stress components from the experimentally measured lattice strains as well as by employing an inverse finite element modeling approach. It is shown that if the NiTi inserts are embedded into the elastic steel matrix following a carefully designed technological procedure, the internal stress fields vary with temperature in a reproducible and predictable way. It is estimated that this mechanism of internal stress generation can be safely applied in the temperature range from −20 °C to 150 °C and is relatively resistant to thermal and mechanical fatigue. The predictability and fatigue endurance of the mechanism are of essential importance for the development of future smart metal matrix composites or smart structures with embedded shape memory alloy components.

  10. Mechanical properties and hot-rolled microstructures of a low carbon bainitic steel with Cu-P alloying

    International Nuclear Information System (INIS)

    Cui, W.F.; Zhang, S.X.; Jiang, Y.; Dong, J.; Liu, C.M.

    2011-01-01

    Highlights: → Mechanical properties and microstructures of low carbon bainite steel are examined. → Cu-P alloying promotes strengthening and uniform plastic deformation. → Cu-P alloying delays recovery process during rolling interval. → Lowering rolling temperature is favorable to increasing toughness. - Abstract: A low carbon bainitic steel with Cu-P alloying was developed. The new steel aims to meet the demand of high strength, high toughness and resistance to chloride ion corrosion for the components used in the environment of sea water and oceanic atmosphere. Mechanical properties of the steel were tested and strengthening and toughening mechanisms were analyzed by comparing hot-rolled microstructures of the low carbon bainitic steels with and without Cu-P alloying. The results show that Cu-P alloying provided strong solution strengthening with weak effect on ductility. The toughness loss caused by Cu-P alloying could be balanced by increasing the amount of martensite/remained austenite (M/A island) at lower finishing temperature. The static recovery process during rolling interval was delayed by the interaction of phosphorous, copper atoms with dislocations, which was favorable to the formation of bainitic plates. Super-fine Nb(C, N) particles precipitated on dislocations had coherency with bainite ferrite at 830 deg. C finishing temperature. Raising finishing temperature to 880 deg. C, Nb(C, N) particles were prone to coarsening and losing coherency. It was also found that no accurate lattice match relationship among retained austenite, martensite and bainite in granular bainitic microstructure.

  11. Mechanical properties and hot-rolled microstructures of a low carbon bainitic steel with Cu-P alloying

    Energy Technology Data Exchange (ETDEWEB)

    Cui, W.F., E-mail: wenfangcui@yahoo.com.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China); Zhang, S.X. [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China); Technology Center of Laiwu Iron and Steel (Group) Co. Ltd., Laiwu 271104 (China); Jiang, Y. [School of Chemical Engineering, University of Queensland, Brisbane 4072 (Australia); Dong, J. [Technology Center of Laiwu Iron and Steel (Group) Co. Ltd., Laiwu 271104 (China); Liu, C.M. [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China)

    2011-08-15

    Highlights: {yields} Mechanical properties and microstructures of low carbon bainite steel are examined. {yields} Cu-P alloying promotes strengthening and uniform plastic deformation. {yields} Cu-P alloying delays recovery process during rolling interval. {yields} Lowering rolling temperature is favorable to increasing toughness. - Abstract: A low carbon bainitic steel with Cu-P alloying was developed. The new steel aims to meet the demand of high strength, high toughness and resistance to chloride ion corrosion for the components used in the environment of sea water and oceanic atmosphere. Mechanical properties of the steel were tested and strengthening and toughening mechanisms were analyzed by comparing hot-rolled microstructures of the low carbon bainitic steels with and without Cu-P alloying. The results show that Cu-P alloying provided strong solution strengthening with weak effect on ductility. The toughness loss caused by Cu-P alloying could be balanced by increasing the amount of martensite/remained austenite (M/A island) at lower finishing temperature. The static recovery process during rolling interval was delayed by the interaction of phosphorous, copper atoms with dislocations, which was favorable to the formation of bainitic plates. Super-fine Nb(C, N) particles precipitated on dislocations had coherency with bainite ferrite at 830 deg. C finishing temperature. Raising finishing temperature to 880 deg. C, Nb(C, N) particles were prone to coarsening and losing coherency. It was also found that no accurate lattice match relationship among retained austenite, martensite and bainite in granular bainitic microstructure.

  12. Effect of Aluminum and Silicon on Atmospheric Corrosion of Low-alloying Steel under Containing NaHSO3 Wet/dry Environment

    International Nuclear Information System (INIS)

    Xinhua, Chen; Junhua, Dong; Enhou, Han; Wei, Ke

    2008-01-01

    The atmospheric corrosion performance of Al-alloying Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at 30 .deg. C and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% NaHSO 3 (pH∼4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage: and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of Fe 3 O 4 and α-FeOOH. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as FeAl 2 O 4 , (Fe, Si) 2 (Fe, Al)O 4 ). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere

  13. Analisa pertumbuhan keausan pahat karbida coated dan uncoated pada alloy steel AISI 4340

    Directory of Open Access Journals (Sweden)

    Sobron Lubis

    2017-03-01

    Full Text Available Abstrak: Keausan pahat merupakan data yang sangat penting dalam perencanaan pemesinan. Penelitian ini menjelaskan tentangpercobaan pertumbuhan keausan pahat pada karbida coated dan uncoated dalam pembubutan bahan alloy steel AISI 4340.Penelitian dilakukan dengan memperhatikan pertumbuhan keausan pada menit 12, 24, 36, 48, 60 sampai didapat VB sebesar0.3 mm untuk kedua mata pahat, sedangkan kondisi pemotongan lain seperti gerak makan, kedalaman potong, kecepatanpotong konstan. Tujuan penelitian ini adalah untuk mengkaji secara ilmiah pertumbuhan keausan yang terjadi pada mata pahatkarbida coated dan uncoated pada proses pemotongan alloy steel AISI 4340. Metode grafik digunakan untuk analisispercobaan, untuk melihat perbandingan pertumbuhan keausan mata pahat karbida coated dan uncoated serta mekanismekeausan yang terjadi, serta korelasi pertumbuhan keausan dengan kekasaran permukaan benda kerja. Hasil penelitianmendapatkan keausan pahat karbida coated pada menit 60 dengan VB sebesar 0.366 mm, sedangkan pada karbida uncoatedpada menit 36 sebesar 0.45 mm. Mekanisme keausan yang terjadi adalah keausan adhesi.Kata Kunci: Pahat potong karbida, baja paduan, keausan pahat, keausan tepi. Abstract: A tool life is an important data in planning a machining process. In this research, an experiment describe about growth of toolwear on carbide coated and uncoated cutting tools used in turning process of an alloy steel of AISI 4340. The experiment wasconducted by observing the growth of tool wear on minutes 12, 24, 36, 48, 60 until get VB 0.3 mm for both of cutting tools, whilethe other cutting conditions such a feed rate, depth of cut, cutting speed constant. The purpose of this experiment is to examinescientifically the growth of tool wear on carbide coated and uncoated in turning process of and alloy steel of AISI 4340. Graphicalmethod used for analisis of the experiment, to compare the growth of tool wear on cutting tool carbide coated and uncoated, andthe

  14. An Industrial Perspective on Environmentally Assisted Cracking of Some Commercially Used Carbon Steels and Corrosion-Resistant Alloys

    Science.gov (United States)

    Ashida, Yugo; Daigo, Yuzo; Sugahara, Katsuo

    2017-08-01

    Commercial metals and alloys like carbon steels, stainless steels, and nickel-based super alloys frequently encounter the problem of environmentally assisted cracking (EAC) and resulting failure in engineering components. This article aims to provide a perspective on three critical industrial applications having EAC issues: (1) corrosion and cracking of carbon steels in automotive applications, (2) EAC of iron- and nickel-based alloys in salt production and processing, and (3) EAC of iron- and nickel-based alloys in supercritical water. The review focuses on current industrial-level understanding with respect to corrosion fatigue, hydrogen-assisted cracking, or stress corrosion cracking, as well as the dominant factors affecting crack initiation and propagation. Furthermore, some ongoing industrial studies and directions of future research are also discussed.

  15. Electrically induced phase transition in GeSbTe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, Gunnar; Schlockermann, Carl; Woda, Michael; Wuttig, Matthias [I. Physikalisches Institut Ia, RWTH Aachen, 52056 Aachen (Germany)

    2008-07-01

    While phase change materials have already successfully been applied in rewriteable optical data storage, they are now also promising to form the basis for novel non-volatile electrical data storage devices. To understand the physical concepts of these so-called Phase Change Random Access Memory (PCRAM) it is mandatory to gain a deeper insight into the switching process between the highly resistive amorphous and the lowly resistive crystalline phase. The fast phase transitions between the amorphous and crystalline state of GeSbTe-based alloys has so far often been studied using pulsed laser irradiation. In this work an alternative approach is employed to investigate this transition. Electrical pulses are used to rapidly and reversibly switch between the two states. For these experiments a setup was built with a specially designed contacting circuit board to meet the requirements of electrical measurements on a nanosecond timescale. The influence of the pulse parameters on the change of device resistance was determined for different initial states. Furthermore the high time resolution of 0.4 ns allows investigation of transient electrical effects like the so-called threshold switching first described by Ovshinsky in the late 1960s.

  16. Electrically induced phase transition in GeSbTe alloys

    International Nuclear Information System (INIS)

    Bruns, Gunnar; Schlockermann, Carl; Woda, Michael; Wuttig, Matthias

    2008-01-01

    While phase change materials have already successfully been applied in rewriteable optical data storage, they are now also promising to form the basis for novel non-volatile electrical data storage devices. To understand the physical concepts of these so-called Phase Change Random Access Memory (PCRAM) it is mandatory to gain a deeper insight into the switching process between the highly resistive amorphous and the lowly resistive crystalline phase. The fast phase transitions between the amorphous and crystalline state of GeSbTe-based alloys has so far often been studied using pulsed laser irradiation. In this work an alternative approach is employed to investigate this transition. Electrical pulses are used to rapidly and reversibly switch between the two states. For these experiments a setup was built with a specially designed contacting circuit board to meet the requirements of electrical measurements on a nanosecond timescale. The influence of the pulse parameters on the change of device resistance was determined for different initial states. Furthermore the high time resolution of 0.4 ns allows investigation of transient electrical effects like the so-called threshold switching first described by Ovshinsky in the late 1960s

  17. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    Science.gov (United States)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-10-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  18. A New Vacuum Brazing Route for Niobium-316L Stainless Steel Transition Joints for Superconducting RF Cavities

    Science.gov (United States)

    Kumar, Abhay; Ganesh, P.; Kaul, R.; Bhatnagar, V. K.; Yedle, K.; Ram Sankar, P.; Sindal, B. K.; Kumar, K. V. A. N. P. S.; Singh, M. K.; Rai, S. K.; Bose, A.; Veerbhadraiah, T.; Ramteke, S.; Sridhar, R.; Mundra, G.; Joshi, S. C.; Kukreja, L. M.

    2015-02-01

    The paper describes a new approach for vacuum brazing of niobium-316L stainless steel transition joints for application in superconducting radiofrequency cavities. The study exploited good wettability of titanium-activated silver-base brazing alloy (CuSil-ABA®), along with nickel as a diffusion barrier, to suppress brittle Fe-Nb intermetallic formation, which is well reported during the established vacuum brazing practice using pure copper filler. The brazed specimens displayed no brittle intermetallic layers on any of its interfaces, but instead carried well-distributed intermetallic particles in the ductile matrix. The transition joints displayed room temperature tensile and shear strengths of 122-143 MPa and 80-113 MPa, respectively. The joints not only exhibited required hermeticity (helium leak rate high vacuum but also withstood twelve hour degassing heat treatment at 873 K (suppresses Q-disease in niobium cavities), without any noticeable degradation in the microstructure and the hermeticity. The joints retained their leak tightness even after undergoing ten thermal cycles between the room temperature and the liquid nitrogen temperature, thereby establishing their ability to withstand service-induced low cycle fatigue conditions. The study proposes a new lower temperature brazing route to form niobium-316L stainless steel transition joints, with improved microstructural characteristics and acceptable hermeticity and mechanical properties.

  19. Cold-workability limits for carbon and alloy steels

    Science.gov (United States)

    El-Domiaty, A.

    1999-04-01

    In metalforming, the success in accomplishing the required deformation without failure of the forming tools or cracking of the work material represents the major concern for manufacture and design engineers. The degree of deformation that can be achieved in a particular metalworking process without creating an undesirable condition is defined as workability. In the present work, an experimental investigation was carried out to determine the cold-workability limits for five different types of steel: AISI 1018, 1045, 1078, 4140, and 4340. The upset (compression) test was used to determine the workability limit for each type. The upset dies and specimen geometries were designed to give different strain paths covering the range from homogeneous deformation (ɛz/ɛθ=-2.0) to close to plane-strain condition (ɛz/ɛθ=0.0). Grid pattern was printed on the specimen surface in order to measure the axial and hoop strain components during deformation. Specific elements were selected on the specimen surface, and their strain paths were determined. Each strain path was terminated once surface cracking had been observed. The ends of the strain paths, at which macrocracks were observed, were connected to obtain the workability limit on the forming-limit diagram. The workability limit of AISI 1018 is the highest among the other types of steel.

  20. Compatibility of graphite with a martensitic-ferritic steel, an austenitic stainless steel and a Ni-base alloy up to 1250 C

    International Nuclear Information System (INIS)

    Hofmann, P.

    1994-08-01

    To study the chemical interactions between graphite and a martensitic-ferritic steel (1.4914), an austenitic stainless steel (1.4919; AISI 316), and a Ni-base alloy (Hastelloy X) isothermal reaction experiments were performed in the temperature range between 900 and 1250 C. At higher temperatures a rapid and complete liquefaction of the components occurred as a result of eutectic interactions. The chemical interactions are diffusion-controlled processes and can be described by parabolic rate laws. The reaction behavior of the two steels is very similar. The chemical interactions of the steels with graphite are much faster above 1100 C than those for the Ni-base alloy. Below 1000 C the effect is opposite. (orig.) [de

  1. Evaluation of the Precipitation Behavior in SA508 Gr. 4N Low Alloy Steel Using a Thermodynamic Calculation

    International Nuclear Information System (INIS)

    Park, Sang Gyu; Wee, Dang Moon; Kim, Min Chul; Lee, Bong Sang

    2007-01-01

    Low carbon low alloy steels, used as nuclear pressure vessels, steam generators and so on, hold a large portion of materials for nuclear power plants, and they are very important materials since they determine the safety and the life span of nuclear power plants. In addition, they are utilized for a long period under very severe conditions such as a high pressure, high temperature, neutron irradiation and corrosion, so they need a good combination of strength and toughness, a good weldability and an excellent neutron irradiation resistance and so on. SA508 Gr.3 steel shows the upper bainite microstructure, which is a less tough, so the steel is more difficult to obtain good toughness than to have good strength. And then, if a loss of toughness due to a neutron irradiation during service is considered, above all improving the toughness is important when a pressure vessel is fabricated It is known that a higher strength and fracture toughness of low alloy steels could be achieved by increasing the Ni and Cr contents. In this study, we have performed a thermodynamic calculation based on the microstructure of SA508 Gr.4N low alloy steel which has higher Ni and Cr contents than SA508 Gr.3 low alloy steel. Based on the microstructure/property relations obtained from literature research experimental works on SA508 Gr.4N steels, and by predicting the constitutional changes with alloying elements (such as Mn, Cr) during individual steps of a steel making process a using thermodynamic calculation, fundamental information for an alloy design have been discussed

  2. Ultra-sonic testing for brittle-ductile transition temperature of ferritic steels

    International Nuclear Information System (INIS)

    Nomakuchi, Michiyoshi

    1979-01-01

    The ultra-sonic testing for the brittle-ductile transition temperature, the USTB test for short, of ferritic steels is proposed in the present paper. And also the application of the USTB test into the nuclear pressure vessel surveillance is discussed. The USTB test is based upon the experimental results in the present work that the ultrasonic pressure attenuation coefficient of a ferritic steel has the evident transition property with its temperature due to the nature from which the brittle-ductile fracture transition property of the steel come and for four ferritic steels the upper boundary temperatute of the region in which the transition of the attenuation coefficient of a steel takes place is 4 to 5 0 C higher than the sub(D)T sub(E), i.e. the transition temperature of the fracture absorption energy of the steel by the DWTT test. The USTB test estimates the crack arrest temperature which is defined to be the fracture transition elastic temperature by the upper boundary temperature. (author)

  3. Irradiation enhanced diffusion and irradiation creep tests in stainless steel alloys

    International Nuclear Information System (INIS)

    Loelgen, R.H.; Cundy, M.R.; Schuele, W.

    1977-01-01

    A review is given of investigations on the rate of phase changes during neutron and electron irradiation in many different fcc alloys showing either precipitation or ordering. The diffusion rate was determined as a function of the irradiation flux, the irradiation temperature and the irradiation dose. It was found that the radiation enhanced diffusion in all the investigated alloys is nearly temperature independent and linearly dependent on the flux. From these results conclusions were drawn concerning the properties of point defects and diffusion mechanisms rate determining during irradiation, which appears to be of a common nature for fcc alloys having a similar structure to those investigated. It has been recognized that the same dependencies which are found for the diffusion rate were also observed for the irradiation creep rate in stainless steels, as reported in literature. On the basis of this observation a combination of measurements is suggested, of radiation enhanced diffusion and radiation enhanced creep in stainless steel alloys. The diffusion tests will be performed at the Euratom Joint Research Centre in Ispra, Italy, and the irradiation creep tests will be carried out in the High Flux Reactor /9/ of the Euratom Joint Research Centre in Petten, The Netherlands. In order to investigate irradiation creep on many samples at a time two special rigs were developed which are distinguished only by the mode of stress applied to the steel specimens. In the first type of rig about 50 samples can be tested uniaxially under tension with various combinations of irradiation temperature and stress. The second type of rig holds up to 70 samples which are tested in bending, again with various combinations of irradiation temperature and stress

  4. Carbonitriding of low alloy steels: Mechanical and metallurgical responses

    Energy Technology Data Exchange (ETDEWEB)

    Dal' Maz Silva, W., E-mail: waltermateriais@me.com [Institut Jean Lamour – UMR CNRS–Université de Lorraine, 7198, Parc de Saurupt, Nancy 54011 (France); Institut de Recherche Technologique M2P, Metz 57070 (France); Dulcy, J., E-mail: jacky.dulcy@univ-lorraine.fr [Institut Jean Lamour – UMR CNRS–Université de Lorraine, 7198, Parc de Saurupt, Nancy 54011 (France); Ghanbaja, J., E-mail: jaafar.ghanbaja@univ-lorraine.fr [Institut Jean Lamour – UMR CNRS–Université de Lorraine, 7198, Parc de Saurupt, Nancy 54011 (France); Redjaïmia, A., E-mail: abdelkrim.redjaimia@univ-lorraine.fr [Institut Jean Lamour – UMR CNRS–Université de Lorraine, 7198, Parc de Saurupt, Nancy 54011 (France); Michel, G., E-mail: gregory.michel@irt-m2p.fr [Institut de Recherche Technologique M2P, Metz 57070 (France); Thibault, S., E-mail: simon.thibault@safran.fr [Safran Tech, Magny les Hameaux (France); Belmonte, T., E-mail: thierry.belmonte@univ-lorraine.fr [Institut Jean Lamour – UMR CNRS–Université de Lorraine, 7198, Parc de Saurupt, Nancy 54011 (France)

    2017-05-02

    Metallurgical and mechanical responses of alloys 16NiCrMo13 and 23MnCrMo5 to the addition of carbon and/or nitrogen were investigated. Diffusion profiles of these interstitial elements were established by atmospheric pressure carburizing, austenitic nitriding, and a sequence of carburizing and nitriding – the carbonitriding. All treatments were performed at 1173 K under CO-H{sub 2} and/or NH{sub 3} based atmospheres. After enrichment, each sample was (i) room-temperature oil-quenched and (ii) immersed in boiling nitrogen prior to (iii) the stress relief treatment. Cross-section hardness profiles were evaluated after each of these steps. Electron probe microanalysis (EPMA) allowed for the determination of both carbon and nitrogen diffusion profiles after quenching. In order to estimate the fraction of nitrides formed during the enrichment of the alloys, these measured profiles were employed in the simulation of local equilibrium at each evaluated position. This allowed for the computation of total solid solution interstitial content, which was expressed in atomic fraction. Plots of as-quenched hardness against the square root of the computed interstitial content, i.e. the sum of solution carbon and the remaining nitrogen, show the complementary character of these elements in determining the mechanical properties of the materials prior to stress relief treatment. Tempering of carbon-nitrogen martensite resulted in hardness drop to a lesser degree than the one measured on carbon martensite with equivalent interstitial content. In order to investigate this behavior, transmission electron microscopy (TEM) analyses were performed. Results showed the precipitation of two morphologies of Fe{sub 16}N{sub 2} in the nitrogen-rich case and image analysis confirmed the simulated fraction of nitrides.

  5. Toughness degradation evaluation of low alloyed steels by electrical resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Nahm, S H; Yu, K M; Kim, S C [Korea Research Inst. of Standards and Science, Taejon (Korea, Republic of); Kim, A [Department of Mechanical Engineering, Kongju Univ., Kongju, Chungnam (Korea, Republic of)

    1997-09-01

    Remaining life of turbine rotors with a crack can be assessed by the fracture toughness on the aged rotors at service temperature. DC potential drop measurement system was constructed in order to evaluate material toughness nondestructively. Test material was 1Cr-1Mo-0.25V steel used widely for turbine rotor material. Seven kinds of specimen with different degradation levels were prepared according to isothermal aging heat treatment at 630 deg. C. Electrical resistivity of test material was measured at room temperature. It was observed that material toughness and electrical resistivity decreased with the increase of degradation. The relationship between fracture toughness and electrical resistivity was investigated. Fracture toughness of a test material may be determined nondestructively by electrical resistivity. (author). 13 refs, 7 figs.

  6. Study of interactions between liquid lead-lithium alloy and austenitic and martensitic steels

    International Nuclear Information System (INIS)

    Simon, N.

    1992-06-01

    In the framework of Fusion Technology, the behaviour of structural materials in presence of liquid alloy Pb17Li is investigated. First, the diffusion coefficients of Fe and Cr have been determined at 500 deg C. Then mass transfer experiments in Pb17Li have been conducted in an anisothermal container with pure metals (Fe, Cr, Ni), Fe-Cr steels and austenitic steels. These experiments showed a very high loss of Nickel, which is an accordance with its high solubility, and Cr showed mass-losses one order of magnitude higher than for pure iron, as the diffusion coefficient of Cr is three orders of magnitude higher than for pure Fe. The corrosion rate of binary Fe-Cr and pure Fe are identical. In austenitic steels, the gamma lattice allows a higher mass-transfer of Cr than the alpha lattice, the presence of Cr slows downs the dissolution of Ni, and the porosity of corrosion layers results of losses of Cr and Ni. Finally, a review of our results and those of other laboratories allowed an identification of the corrosion limiting step. In the case of 1.4914 martensitic steel it is the diffusion of Fe in Pb17Li, while in the case of 316L austenitic steel it is the diffusion of Cr in Pb17Li

  7. The effect of alloying elements on the creep and impact properties of high Cr steels

    International Nuclear Information System (INIS)

    Kim, S. H.; Song, B. J.; Ryu, W. S.

    2000-01-01

    The effect of minor alloying elements on the creep and impact properties in high Cr steels has been studied. The addition of W and N in creased the creep rupture strength without the decrease of the impact toughness. During deformation, growth of lath width and agglomeration of precipitates and precipitation of Laves phase occurred. These microstructural changes made the steels soften. The degree of softening was delayed by the addition of W and N. In W added steel, the Laves phase had a important role in increasing the creep rupture strength. But the impact toughness was rapidly degraded by the addition of W after aging at 600 .deg. C for 5000 hours. So it needs to evaluate more accurately the effect of Laves phase on creep and impact properties. In N added steel, V(C,N) was precipitated in lath boundary and interior of lath. The size of the precipitates was 20-50nm. The increase of creep rupture strength in N added steel may be due to the precipitate of the V(C,N). So it needs more test to clarify the effect of N on the creep and impact properties

  8. Effects of Si as alloying element on corrosion resistance of weathering steel

    International Nuclear Information System (INIS)

    Mejía Gómez, J.A.; Antonissen, J.; Palacio, C.A.; De Grave, E.

    2012-01-01

    Highlights: ► Weathering steels with different concentrations of Si as alloying element were exposed to laboratory atmospheric conditions. ► The iron oxides formed as corrosion products were characterized and analyzed by XRD, TEM and Mössbauer spectroscopy. ► Silicon affects the corrosion resistance of weathering steels. ► Silicon promotes the formation of goethite as corrosion product with small particle size. - Abstract: The corrosion resistance in saline conditions of weathering steel with different concentrations of Si (1, 2 and 3 wt.%) exposed to dip dry tests (simulating wet/dry cycles of atmospheric corrosion) was studied by weight loss, X-ray diffraction, Mössbauer spectroscopy and transmission electron microscopy. The results showed that the steels exhibit better corrosion performance with increasing Si concentration. The formation of Fe-oxides such as goethite, lepidocrocite and magnetite was observed. Superparamagnetic goethite is the dominant phase in the rust developed on the Si steels, indicating that Si favors the formation of goethite with small particle size.

  9. Effects of Zr Addition on Strengthening Mechanisms of Al-Alloyed High-Cr ODS Steels.

    Science.gov (United States)

    Ren, Jian; Yu, Liming; Liu, Yongchang; Liu, Chenxi; Li, Huijun; Wu, Jiefeng

    2018-01-12

    Oxide dispersion strengthened (ODS) steels with different contents of zirconium (denoted as 16Cr ODS, 16Cr-0.3Zr ODS and 16Cr-0.6Zr ODS) were fabricated to investigate the effects of Zr on strengthening mechanism of Al-alloyed 16Cr ODS steel. Electron backscatter diffraction (EBSD) results show that the mean grain size of ODS steels could be decreased by Zr addition. Transmission electron microscope (TEM) results indicate that Zr addition could increase the number density but decrease the mean diameter and inter-particle spacing of oxide particles. Furthermore, it is also found that in addition to Y-Al-O nanoparticles, Y-Zr-O oxides with finer size were observed in 16Cr-0.3Zr ODS and 16Cr-0.6Zr ODS steels. These changes in microstructure significantly increase the yield strength (YS) and ultimate tensile strength (UTS) of ODS steels through mechanisms of grain boundary strengthening and dispersion strengthening.

  10. Effects of alloying elements on sticking occurring during hot rolling of ferritic stainless steels

    International Nuclear Information System (INIS)

    Ha, Dae Jin; Kim, Yong Jin; Lee, Yong Deuk; Lee, Sung Hak; Lee, Jong Seog

    2008-01-01

    In this study, effects of alloying elements on the sticking occurring during hot rolling of five kinds of ferritic STS430J1L stainless steels were investigated by analyzing high-temperature hardness and oxidation behavior of the rolled steels. Hot-rolling simulation tests were conducted by a high-temperature wear tester which could simulate actual hot rolling. The simulation test results revealed that the sticking process proceeded with three stages, i.e., nucleation, growth, and saturation. Since the hardness continuously decreased as the test temperature increased, whereas the formation of Fe-Cr oxides in the rolled steel surface region increased, the sticking of five stainless steels was evaluated by considering both the high-temperature hardness and oxidation effects. The addition of Zr, Cu, or Si had a beneficial effect on the sticking resistance, while the Ni addition did not show any difference in the sticking. Particularly in the case of the Si addition, Si oxides formed first in the initial stage of high-temperature oxidation, worked as initiation sites for Fe-Cr oxides, accelerated the formation of Fe-Cr oxides, and thus raised the sticking resistance by about 10 times in comparison with the steel without Si content

  11. High-alloy steels and nickel alloys for construction of industrial plants. Pt. 2

    International Nuclear Information System (INIS)

    2007-01-01

    Vol. 2 of the 8. Dresden Corrosion Protection Seminar comprises eight papers, most of which are in the form of PowerPoint presentations: High-temperature materials and their applications in chemical engineering (J. Kloever); Alloy 602 CA in metal dusting conditions; Material requirements in future power plants (H. Schneider); Status report on material qualification for the 700 C technology in coal power plants (R. Mohrmann); Materials for nuclear fusion (M. Paju); The degradation mechanism relaxation cracking as exemplified by the alloys 800 H and 617 (H.C. van Wortel); Specific requirements on the design of a pressurised manifold of Alloy 800 H in refineries, a case study (I. Rommerskirchen et al.); Materials for electro-surfacing for corrosion protection in conditions of high-temperature corrosion (M.Spiegel) [de

  12. Welding of Aluminum Alloys to Steels: An Overview

    Science.gov (United States)

    2013-08-01

    and deformations are a few examples of the unwanted consequences which somehow would lead to brittle fracture, fatigue fracture, shape instability...was made under the copper tips of the spot welding machine. The fatigue results showed higher fatigue strength of the joints with transition layer...kHz ultrasonic butt welding system with a vibration source applying eight bolt-clamped Langevin type PZT transducers and a 50 kW static induction

  13. Is galvanic corrosion between titanium alloy and stainless steel spinal implants a clinical concern?

    Science.gov (United States)

    Serhan, Hassan; Slivka, Michael; Albert, Todd; Kwak, S Daniel

    2004-01-01

    Surgeons are hesitant to mix components made of differing metal classes for fear of galvanic corrosion complications. However, in vitro studies have failed to show a significant potential for galvanic corrosion between titanium and stainless steel, the two primary metallic alloys used for spinal implants. Galvanic corrosion resulting from metal mixing has not been described in the literature for spinal implant systems. To determine whether galvanic potential significantly affects in vitro corrosion of titanium and stainless steel spinal implant components during cyclical compression bending. Bilateral spinal implant constructs consisting of pedicle screws, slotted connectors, 6.35-mm diameter rods and a transverse rod connector assembled in polyethylene test blocks were tested in vitro. Two constructs had stainless steel rods with mixed stainless steel (SS-SS) and titanium (SS-Ti) components, and two constructs had titanium rods with mixed stainless steel (Ti-SS) and titanium (Ti-Ti) components. Each construct was immersed in phosphate-buffered saline (pH 7.4) at 37 C and tested in cyclic compression bending using a sinusoidal load-controlling function with a peak load of 300 N and a frequency of 5 Hz until a level of 5 million cycles was reached. The samples were then removed and analyzed visually for evidence of corrosion. In addition, scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were used to evaluate the extent of corrosion at the interconnections. None of the constructs failed during testing. Gross observation of the implant components after disassembly revealed that no corrosion had occurred on the surface of the implants that had not been in contact with another component. The Ti-Ti interfaces showed some minor signs of corrosion only detectable using SEM and EDS. The greatest amount of corrosion occurred at the SS-SS interfaces and was qualitatively less at the SS-Ti and Ti-SS interfaces. The results from this study indicate

  14. Research of Steel-dielectric Transition Using Subminiature Eddy-current Transducer

    Science.gov (United States)

    Dmitriev, S. F.; Malikov, V. N.; Sagalakov, A. M.; Ishkov, A. V.

    2018-05-01

    The research aims to develop a subminiature transducer for electrical steel investigation. The authors determined the capability to study steel characteristics at different depths based on variations of eddy-current transducer amplitude at the steel-dielectric boundary. A subminiature transformer-type transducer was designed, which enables to perform local investigations of ferromagnetic materials using an eddy-current method based on local studies of the steel electrical conductivity. Having the designed transducer as a basis, a hardware-software complex was built to perform experimental studies of steel at the interface boundary. Test results are reported for a specimen with continuous and discrete measurements taken at different frequencies. The article provides the key technical information about the eddy current transformer used and describes the methodology of measurements that makes it possible to control steel to dielectric transition.

  15. Temperature and environmentally assisted cracking in low alloy steel

    International Nuclear Information System (INIS)

    Auten, T.A.; Monter, J.V.

    1995-01-01

    Environmentally assisted cracking (EAC) can be defined as the propagation of fatigue cracks in water at rates that are anywhere from 3 to over 40 times the growth rates expected in air. In the present work, five ASTM A 508 Class 2 forgings with ladle and check analyses that ranged from 0.010 to 0.019 wt% S were tested in high purity deaerated water in the temperature range of 93 to 260 C. At 260 C these forgings did not undergo EAC, reinforcing earlier results for two similar forgings. This broad sampling indicates a strong resistance to EAC for this class of forging at 260 C. On the other hand, EAC occurred consistently in the three of these forgings that were tested below 204 C, provided the test conditions were high enough to produce a high baseline fatigue crack growth rate (FCGR), where the baseline FCGR is that expected in air. At 149 C, EAC occurred at test conditions that combined to yield a baseline FCGR greater than ∼2E-6 mm/s. At 204, 121, and 93 C, this ''critical crack growth rate'' appeared to shift to lower baseline values. The EAC that occurred at lower temperatures was a factor of 3 to 12 times higher than baseline air rates, which was not as strong as the effect for higher sulfur steels at 240 to 290 C. Also, no plateau in the growth rates occurred as it does with the higher sulfur steels. In another approach, EAC was induced at 93 and at 260 C by raising the dissolved oxygen content of the water from 15 ppb. In this case, the EAC growth rates decreased to non-EAC levels when the oxygen supply was shut off. The oxygen-related EAC occurred over a broader range of baseline growth rates than found for the EAC driven by the baseline crack tip speed. Again, this can be rationalized by the buildup of sulfur in the crack tip water, which can be associated with the higher corrosion potential of the bulk water

  16. Characterization of the dissimilar welding - austenitic stainless steel with filler metal of the nickel alloy

    International Nuclear Information System (INIS)

    Soares, Bruno Amorim; Schvartzman, Monica Maria de Abreu Mendonca; Campos, Wagner Reis da Costa

    2007-01-01

    In elevated temperature environments, austenitic stainless steel and nickel alloy has a superior corrosion resistance due to its high Cr content. Consequently, this alloys is widely used in nuclear reactors components and others plants of energy generation that burn fossil fuel or gas, chemical and petrochemical industries. The object of the present work was to research the welding of AISI 304 austenitic stainless steel using the nickel alloy filler metals, Inconel 625. Gas tungsten arc welding, mechanical and metallographic tests, and compositional analysis of the joint were used. A fundamental investigation was undertaken to characterize fusion boundary microstructure and to better understand the nature and character of boundaries that are associated with cracking in dissimilar welds. The results indicate that the microstructure of the fusion zone has a dendritic structure, inclusions, and precipitated phases containing Ti and Nb are present in the inter-dendritic region. In some parts near to the fusion line it can be seen a band in the weld, probably a eutectic phase with lower melting point than the AISI 304, were the cracking may be beginning by stress corrosion. (author)

  17. Microstructural evolution of ferritic steel powder during mechanical alloying with iron oxide

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Yuren; Liu, Yong; Liu, Donghua; Tang, Bei [Central South Univ., State Key Lab. of Powder Metallurgy, Changsha (China); Liu, C.T. [The Hong Kong Polytechnic Univ., Dept. of Mechanical Engineering, Hong Kong (China)

    2011-02-15

    Mechanical alloying of mixed powders is of great importance for preparing oxide dispersion strengthened ferritic steels. In this study, the microstructural evolution of ferritic steel powder mixed with TiH{sub x}, YH{sub 2} and Fe{sub 2}O{sub 3} in the process of mechanical alloying is systematically investigated by using X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy and microhardness tests. It is found that titanium, yttrium hydrides and iron oxide are completely dissolved during milling, and homogeneous element distribution can be achieved after milling for 12 h. The disintegration of the composite powder particles occurs at 24 h and reaches the balance of welding and fracturing after 36 h. The oxygen content increases sharply with the disintegration of powder particles due to the absorption of oxygen at the solid/gas interface from the milling atmosphere, which is the main source of extra oxygen in the milled powder. Grain refinement down to nanometer level occurs due to the severe plastic deformation of particles; however, the grain size does not change much with further disintegration of particles. The hardness increases with milling time and then becomes stable during further milling. The study indicates that the addition of iron oxide and hydrides may be more beneficial for the dispersion and homogenization of chemical compositions in the powder mixture, thus shortening the mechanical alloying process. (orig.)

  18. A study of roll-bonding MS90 alloy to steel utilizing chromized interlayer

    International Nuclear Information System (INIS)

    Tolaminejad, B.; Arabi, H.

    2008-01-01

    This article describes a study of the application of a roll bonding technique to MS90(CuZn10) alloy strips and steel sheets using a chromized interlayer. It was found that the overall bond between these two metals resulted from two different types of bonds: a block bond, linking the MS90 alloy strips and chromium topcoat layer, and a blank bond, linking the MS90 alloy strips and bare steel surface in the area where the chromium coating has been fragmented. This study investigated the effects of plating time on the thickness of the coating layers and of the area fraction of the blank bond on the bond strength. The overall bond strength depends mainly on the strength and the area fraction of the blank bond. A linear relationship model exists between the overall bond strength and the area fraction of the blank bond. The bond strength of the blank bond was eight times greater than that of the block bond. The area fraction of the blank bond increased with increasing the coating thickness up to 55 μm, but thereafter decreased due to the rotation of the chromium blocks

  19. Oxidation of 316 stainless steel and other alloys in prototypic GCFR environments

    International Nuclear Information System (INIS)

    Acharya, R.T.

    1980-05-01

    The oxidation behavior of type 316 stainless steel and candidate advanced alloys for the gas-cooled fast reactor (GCFR) is being investigated at General Atomic Company. The test program consists of oxidation tests in prototypic GCFR environments. Two tests have been completed to date and a third test is under way. The first test was performed in an environment containing a hydrogen/water ratio of 10. The oxidation behavior of all the alloys was good to excellent in this environment. Preferential oxidation of chromium was responsible for this behavior. The second test was performed in an environment containing a hydrogen/water ratio of 0.25, where both chromium and iron oxides are thermodynamically stable. Some of the alloys and some of the ribbed type 316 stainless steel test specimens showed unacceptable oxidation resistance in this environment. In the third test, presently under way, two different pretreatment procedures are being used to control the poor oxidation behavior observed in the second test. Early results show some degree of success

  20. Wear characterization of a tool steel surface modified by melting and gaseous alloying

    International Nuclear Information System (INIS)

    Rizvi, S.A.

    1999-01-01

    Hot forging dies are subjected to laborious service conditions and so there is a need to explore means of improving die life to increase productivity and quality of forgings. Surface modification in order to produce wear resistant surface is an attractive method as it precludes the need to use expensive and highly alloyed steels. In this study, a novel, inexpensive surface modification technique is used to improve the tri biological properties of an H13 tool steel. Surface melting was achieved using a tungsten heat source and gaseous alloying produced under a shield of argon, carbon dioxide, carbon dioxide-argon mixture and nitrogen gases. The change in wear behaviour was compared through micro-hardness indentation measurements and using a dry sliding pin-on-plate wear testing machine. This study shows superior wear behaviour of the modified surfaces when compared to the untreated surfaces. The increase in wear resistance is attributed to the formation of carbides when surfaces are melted under a carbon dioxide shield. However, in the case of nitrogen and argon gaseous alloying, an increase in wear resistance can be attributed to an increase in surface hardness which in turn effects surface deformation behaviour. (author)

  1. Surface modification of steels and magnesium alloy by high current pulsed electron beam

    Science.gov (United States)

    Hao, Shengzhi; Gao, Bo; Wu, Aimin; Zou, Jianxin; Qin, Ying; Dong, Chuang; An, Jian; Guan, Qingfeng

    2005-11-01

    High current pulsed electron beam (HCPEB) is now developing as a useful tool for surface modification of materials. When concentrated electron flux transferring its energy into a very thin surface layer within a short pulse time, superfast processes such as heating, melting, evaporation and consequent solidification, as well as dynamic stress induced may impart the surface layer with improved physico-chemical and mechanical properties. This paper presents our research work on surface modification of steels and magnesium alloy with HCPEB of working parameters as electron energy 27 keV, pulse duration ∼1 μs and energy density ∼2.2 J/cm2 per pulse. Investigations performed on carbon steel T8, mold steel D2 and magnesium alloy AZ91HP have shown that the most pronounced changes of phase-structure state and properties occurring in the near-surface layers, while the thickness of the modified layer with improved microhardness (several hundreds of micrometers) is significantly greater than that of the heat-affected zone. The formation mechanisms of surface cratering and non-stationary hardening effect in depth are discussed based on the elucidation of non-equilibrium temperature filed and different kinds of stresses formed during pulsed electron beam melting treatment. After the pulsed electron beam treatments, samples show significant improvements in measurements of wear and corrosion resistance.

  2. Surface modification of steels and magnesium alloy by high current pulsed electron beam

    International Nuclear Information System (INIS)

    Hao, Shengzhi; Gao, Bo; Wu, Aimin; Zou, Jianxin; Qin, Ying; Dong, Chuang; An, Jian; Guan, Qingfeng

    2005-01-01

    High current pulsed electron beam (HCPEB) is now developing as a useful tool for surface modification of materials. When concentrated electron flux transferring its energy into a very thin surface layer within a short pulse time, superfast processes such as heating, melting, evaporation and consequent solidification, as well as dynamic stress induced may impart the surface layer with improved physico-chemical and mechanical properties. This paper presents our research work on surface modification of steels and magnesium alloy with HCPEB of working parameters as electron energy 27 keV, pulse duration ∼1 μs and energy density ∼2.2 J/cm 2 per pulse. Investigations performed on carbon steel T8, mold steel D2 and magnesium alloy AZ91HP have shown that the most pronounced changes of phase-structure state and properties occurring in the near-surface layers, while the thickness of the modified layer with improved microhardness (several hundreds of micrometers) is significantly greater than that of the heat-affected zone. The formation mechanisms of surface cratering and non-stationary hardening effect in depth are discussed based on the elucidation of non-equilibrium temperature filed and different kinds of stresses formed during pulsed electron beam melting treatment. After the pulsed electron beam treatments, samples show significant improvements in measurements of wear and corrosion resistance

  3. Effect of composition on corrosion resistance of high-alloy austenitic stainless steel weld metals

    International Nuclear Information System (INIS)

    Marshall, P.I.; Gooch, T.G.

    1993-01-01

    The corrosion resistance of stainless steel weld metal in the ranges of 17 to 28% chromium (Cr), 6 to 60% nickel (Ni), 0 to 9% molybdenum (Mo), and 0.0 to 0.37% nitrogen (N) was examined. Critical pitting temperatures were determined in ferric chloride (FeCl 3 ). Passive film breakdown potentials were assessed from potentiodynamic scans in 3% sodium chloride (NaCl) at 50 C. Potentiodynamic and potentiostatic tests were carried out in 30% sulfuric acid (H 2 SO 4 ) ar 25 C, which was representative of chloride-free acid media of low redox potential. Metallographic examination and microanalysis were conducted on the test welds. Because of segregation of alloying elements, weld metal pitting resistance always was lower than that of matching composition base steel. The difference increased with higher Cr, Mo, and N contents. Segregation also reduced resistance to general corrosion in H 2 SO 4 , but the effect relative to the base steel was less marked than with chloride pitting. Segregation of Cr, Mo, and N in fully austenitic deposits decreased as the Ni' eq- Cr' eq ratio increased. Over the compositional range studied, weld metal pitting resistance was dependent mainly on Mo content and segregation. N had less effect than in wrought alloys. Both Mo and N enhanced weld metal corrosion resistance in H 2 SO 4

  4. Study of electroless Ni-W-P alloy coating on martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Nikitasari, Arini, E-mail: arini-nikitasari@yahoo.com; Mabruri, Efendi, E-mail: efendi-lipi@yahoo.com [Research Center for Metallurgy and Materials, Indonesian Institute of Sciences (470 Building, Puspiptek, Serpong, Indonesia 15313) (Indonesia)

    2016-04-19

    Electroless nickel phospor (Ni-P) is widely used in many industries due to their corrosion and wear resistance, coating uniformity, and ability to coat non-conductive surfaces. The unique properties of tungsten such as high hardness, higher melting point, lower coefficient of linear thermal expansion, and high tensile strength have created a lot of interest in developing ternary Ni-W-P alloys. This article presents the study of electroless Ni-W-P alloys coating using acid or alkaline bath on martensitic stainless steel. Nickel sulfate and sodium tungstate were used as nickel and tungsten sources, respectively, and sodium hypophosphite was used as a reducing agent. Acid or alkaline bath refer to bath pH condition was adjusted by adding sulfuric acid. Martensitic stainless steel was immersed in Ni-W-P bath for 15, 30, and 60 minutes. The substrate of martensitic stainless steel was subjected to pre-treatment (polishing and cleaning) and activation prior to electroless plating. The plating characteristics were investigated for concentration ratio of nickel and hypophosphite (1:3), sodium tungstate concentration 0,1 M, immersion time (15 min, 30 min, 60 min), and bath condition (acid, alkaline). The electroless Ni-W-P plating was heat treated at 400°C for 1 hour. Deposits were characterized using scanning electron microscope (SEM) and corrosion measurement system (CMS).

  5. Effects of Alloying Elements (Cr, Mn) on Corrosion Properties of Carbon Steel in Synthetic Seawater

    International Nuclear Information System (INIS)

    Hyun, Youngmin; Kim, Heesan

    2016-01-01

    Effects of alloying elements, manganese and chromium, on corrosion resistance of carbon steel were examined using weight loss test and electrochemical tests (polarization test and electrochemical impedance spectroscopy (EIS)) in synthetic seawater at 60 ℃. The results from the weight loss test showed that chromium effectively improved corrosion resistance of carbon steel during the entire immersion time, but manganese improved corrosion resistance after the lowered corrosion resistance at the beginnings of immersion. Unlike the weight loss test, the electrochemical tests showed that the corrosion resistance did not increase with immersion time, in all the specimens. This disagreement is explained by the presence of rust involved in electrochemical reaction during electrochemical tests. The analysis of rust with transmission electron microscopy (TEM)−energy dispersive spectroscopy (EDS) showed that the amorphous-like rust layer located at the metal/rust interface with enriched alloying element (Cr, Mn) prevents diffusion of corrosive species into a metal/rust interface effectively, which leads to increased corrosion resistance. The initial corrosion behaviour is also affected by the rust types. In other words, manganese accelerated the formation of spinel oxides, negatively affecting corrosion resistance. Meanwhile, chromium accelerated the formation of goethite but impeded the formation of spinel oxides, positively affecting the corrosion resistance. From the above results, the corrosion resistance of steel is closely related with a rust type.

  6. Effects of Alloying Elements (Cr, Mn) on Corrosion Properties of Carbon Steel in Synthetic Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Youngmin; Kim, Heesan [Hongik University, Sejong (Korea, Republic of)

    2016-02-15

    Effects of alloying elements, manganese and chromium, on corrosion resistance of carbon steel were examined using weight loss test and electrochemical tests (polarization test and electrochemical impedance spectroscopy (EIS)) in synthetic seawater at 60 ℃. The results from the weight loss test showed that chromium effectively improved corrosion resistance of carbon steel during the entire immersion time, but manganese improved corrosion resistance after the lowered corrosion resistance at the beginnings of immersion. Unlike the weight loss test, the electrochemical tests showed that the corrosion resistance did not increase with immersion time, in all the specimens. This disagreement is explained by the presence of rust involved in electrochemical reaction during electrochemical tests. The analysis of rust with transmission electron microscopy (TEM)−energy dispersive spectroscopy (EDS) showed that the amorphous-like rust layer located at the metal/rust interface with enriched alloying element (Cr, Mn) prevents diffusion of corrosive species into a metal/rust interface effectively, which leads to increased corrosion resistance. The initial corrosion behaviour is also affected by the rust types. In other words, manganese accelerated the formation of spinel oxides, negatively affecting corrosion resistance. Meanwhile, chromium accelerated the formation of goethite but impeded the formation of spinel oxides, positively affecting the corrosion resistance. From the above results, the corrosion resistance of steel is closely related with a rust type.

  7. Effects of gaseous nitriding AISI4140 alloy steel on corrosion and hardness properties

    Science.gov (United States)

    Tamil Moli, L.; Wahab, N.; Gopinathan, M.; Karmegam, K.; Maniyarasi, M.

    2016-10-01

    Corrosion is one of the major problems in the industry especially on machinery since it weakens the structure of the machinery part and causes the mechanical failure. This will stop the production and increase the maintenance cost. In this study, the corrosion behaviour of gas nitriding on a screw press machine shaft made from AISI 4140 steel was investigated. Pitting corrosion was identified as a major cause of the shaft failure and this study was conducted to improve the corrosion resistance on the AISI 4140 alloy steel shaft by gas nitriding as a surface hardening treatment. Gas nitriding was performed with composition of 15% ammonia and 85% nitrogen at temperatures of 525 °C, 550 °C and 575 °C and with the soaking time of 30, 45 and 60 minutes, respectively. The samples were prepared as rectangular sized of 30mm x 12mm x 3mm for immersion testing. The results showed that corrosion rate of untreated samples was 77% higher compared to the nitrided samples. It was also found that hardness of the nitrided samples was higher than untreated sample. All in all, it can be concluded that gaseous nitriding can significantly improve the surface hardness and the corrosion resistance of the shaft made of AISI 4140 alloy steel, hence reduces the pitting that is the root cause of failure.

  8. The Study on Environmental Fatigue Behavior of Low Alloy Steel and Stainless Steel Pipes Using the Simplified Plant Transients

    International Nuclear Information System (INIS)

    Yoo, One; Song, M. S.; Kim, I. Y.; Park, S. H.; Lee, B. S.

    2010-01-01

    Nuclear components categorized as ASME Code Class 1 shall be evaluated for the fatigue and satisfy the fatigue acceptance criteria, CUF(cumulative usage factor) < 1 in accordance with ASME Code. However, recent studies have shown the fatigue evaluation procedure may not give conservative results when the components operate in the water environment. NRC issued Regulatory Guide 1.207 which enforces the new fatigue evaluation method or Fen(environmental fatigue correction factor) method to nuclear plants to be newly constructed. This paper describes the characteristics of the behavior of low alloy and austenitic stainless steel straight pipe related to environmental fatigue, which are obtained by using the method suggested by Regulatory Guide 1.207 and simplified plant transients

  9. Microstructure design of low alloy transformation-induced plasticity assisted steels

    Science.gov (United States)

    Zhu, Ruixian

    The microstructure of low alloy Transformation Induced Plasticity (TRIP) assisted steels has been systematically varied through the combination of computational and experimental methodologies in order to enhance the mechanical performance and to fulfill the requirement of the next generation Advanced High Strength Steels (AHSS). The roles of microstructural parameters, such as phase constitutions, phase stability, and volume fractions on the strength-ductility combination have been revealed. Two model alloy compositions (i.e. Fe-1.5Mn-1.5Si-0.3C, and Fe-3Mn-1Si-0.3C in wt%, nominal composition) were studied. Multiphase microstructures including ferrite, bainite, retained austenite and martensite were obtained through conventional two step heat treatment (i.e. intercritical annealing-IA, and bainitic isothermal transformation-BIT). The effect of phase constitution on the mechanical properties was first characterized experimentally via systematically varying the volume fractions of these phases through computational thermodynamics. It was found that martensite was the main phase to deteriorate ductility, meanwhile the C/VA ratio (i.e. carbon content over the volume fraction of austenite) could be another indicator for the ductility of the multiphase microstructure. Following the microstructural characterization of the multiphase alloys, two microstructural design criteria (i.e. maximizing ferrite and austenite, suppressing athermal martensite) were proposed in order to optimize the corresponding mechanical performance. The volume fraction of ferrite was maximized during the IA with the help of computational thermodyanmics. On the other hand, it turned out theoretically that the martensite suppression could not be avoided on the low Mn contained alloy (i.e. Fe- 1.5Mn-1.5Si-0.3C). Nevertheless, the achieved combination of strength (~1300MPa true strength) and ductility (˜23% uniform elongation) on the low Mn alloy following the proposed design criteria fulfilled the

  10. Effect of antimony on the corrosion behavior of low-alloy steel for flue gas desulfurization system

    International Nuclear Information System (INIS)

    Le, D.P.; Ji, W.S.; Kim, J.G.; Jeong, K.J.; Lee, S.H.

    2008-01-01

    The alloying effect of Sb in a new low-alloy steel for the purpose of FGD materials was investigated by potentiodynamic polarization, linear polarization resistance measurement, electrochemical impedance spectroscopy (EIS) and weight loss measurements in an aggressive solution of 16.9 vol.% H 2 SO 4 + 0.35 vol.% HCl (modified green death solution) at 60 deg. C, pH -0.3. All measurements confirmed the marked improvement in the corrosion behavior of the low-alloy steel via the addition of a small amount of Sb, particularly for the 0.10Sb steel. Pitting corrosion was detected by scanning electron microscopy (SEM) on the surface of blank steel and 0.05Sb steel, but not 0.10Sb steel, after weight loss measurements. X-ray photoelectron spectroscopy (XPS) analysis of the corroded surfaces after EIS and linear polarization measurements showed that the decrease in corrosion rates was due to the formation of a protective Sb 2 O 5 oxide film on the surface of the Sb-containing steels. Moreover, the addition of 0.10% Sb stimulated the development of high corrosion inhibiting, Cu-containing compounds which further inhibited the anodic and cathodic reactions

  11. Crystallization, the cast structure and the formation of gas blowholes in high-nitrogen steels and alloy steels

    International Nuclear Information System (INIS)

    Svyazhin, A.G.; Prokoshkina, V.; Kaputkina, L.M.; Siwka, J.; Skuza, Z.

    2001-01-01

    In the paper, the results of experimental research concerning the precipitation of nitrogen in the form of gas blowholes during the crystallization of supersaturated Fe-N, Fe-O-S-N alloys and 1Cr13 and Cr18Ni10 steels have been described. It has been found that the precipitation of nitrogen gas blowholes is more intensive and the pressure p N 2 is higher at low contents of surface active elements, i.e. oxygen and sulfur. At the concentration ([%O] +0.5%[%S]) ≥ 300 ppm, microingots exhibited a compact microstructure without gas blowholes. The result of kinetic analysis of the process of desorption of nitrogen and the thermodynamics of the investigated solution (including surface tension) confirm that the surface reaction plays a decisive role in the formation of gas blowholes. For this reason, it is possible to eliminate the formation of blowholes in ingots of ferritic and ferritic-austenitic steels by introducing such SAE admixtures, as Sb, Te or Se. Analytical expression have been obtained, which define the amount of nitrogen releasing into gas blowholes and describe the conditions of producing ingots or castings of an compact structure at cooling rates of approximately 10 3 K/s. (author)

  12. Influence of heat input on weld bead geometry using duplex stainless steel wire electrode on low alloy steel specimens

    Directory of Open Access Journals (Sweden)

    Ajit Mondal

    2016-12-01

    Full Text Available Gas metal arc welding cladding becomes a popular surfacing technique in many modern industries as it enhances effectively corrosion resistance property and wear resistance property of structural members. Quality of weld cladding may be enhanced by controlling process parameters. If bead formation is found acceptable, cladding is also expected to be good. Weld bead characteristics are often assessed by bead geometry, and it is mainly influenced by heat input. In this paper, duplex stainless steel E2209 T01 is deposited on E250 low alloy steel specimens with 100% CO2 gas as shielding medium with different heats. Weld bead width, height of reinforcement and depth of penetration are measured. Regression analysis is done on the basis of experimental data. Results reveal that within the range of bead-on-plate welding experiments done, parameters of welding geometry are on the whole linearly related with heat input. A condition corresponding to 0.744 kJ/mm heat input is recommended to be used for weld cladding in practice.

  13. Laws of alloyed cementite particles nucleation during heat-resistant steels carburizing

    Directory of Open Access Journals (Sweden)

    M. Yu. Semenov

    2014-01-01

    Full Text Available The article considers a problem analyzing a nucleation of cementite type carbides in carburized heat-resistant steels for the turbofan engines gear wheels.The verification of previously hypothesized mechanism of dislocation nucleation particles chromium-alloyed cementite during process of carburizing was accepted as an objective of the work.As a methodological basis of this paper were accepted the numerical experiments based on the kinetic theory of nucleation, as well as on the known results of experimental studies.According to the kinetic theory of nucleation, a new phase in the solid solutions take place in the defects of the crystal structure of the metal such as inter-grain boundaries and dislocations clusters. A principle feature of the inter-grain boundary mechanism of nucleation is formation of carbide lattice. It is of great practical interest because the cementite lattice drops mechanical properties of hardened parts.According to the experimental studies, the average chromium concentration in the alloyed cementite twice exceeds its Cr content in the heat-resistant steels. Furthermore, the areas of abnormally high (more than ten times in comparison with the average content chromium concentration in cementite have been experimentally revealed.Numerical experiments have revealed that the nucleation of cementite particles alloyed with chromium (chromium concentration of 3% or more occurs, mainly, by the dislocation mechanism on the concentration fluctuations of the alloying element. According to calculations, an obligatory prerequisite to start an active nucleation process of new phase in the solid solution is a local increase of the chromium concentration up to 40%.Despite the lack of physical prerequisites for the formation of chromium precipitates, this phenomenon is explained by a strong chemical affinity of chromium and carbon, causing diffusion of chromium atoms in the region of the carbon atoms clusters. The formation of carbon

  14. Surface Modification of Micro-Alloyed High-Strength Low-Alloy Steel by Controlled TIG Arcing Process

    Science.gov (United States)

    Ghosh, P. K.; Kumar, Ravindra

    2015-02-01

    Surface modification of micro-alloyed HSLA steel plate has been carried out by autogenous conventional and pulse current tungsten inert gas arcing (TIGA) processes at different welding parameters while the energy input was kept constant. At a given energy input the influence of pulse parameters on the characteristics of surface modification has been studied in case of employing single and multi-run procedure. The role of pulse parameters has been studied by considering their summarized influence defined by a factor Φ. The variation in Φ and pulse frequency has been found to significantly affect the thermal behavior of fusion and accordingly the width and penetration of the modified region along with its microstructure, hardness and wear characteristics. It is found that pulsed TIGA is relatively more advantageous over the conventional TIGA process, as it leads to higher hardness, improved wear resistance, and a better control over surface characteristics.

  15. The effect of σ-phase precipitation at 800°C on the corrosion resistance in sea-water of a high alloyed duplex stainless steel

    NARCIS (Netherlands)

    Wilms, M.E.; Gadgil, V.J.; Krougman, J.M.; Ijsseling, F.P.

    1994-01-01

    Super-duplex stainless steels are recently developed high alloyed stainless steels that combine good mechanical properties with excellent corrosion resistance. Because of a high content of chromium and molybdenum, these alloys are susceptible to σ-phase precipitation during short exposure to

  16. Influence of laser radiation on structure and properties of steels and alloys

    International Nuclear Information System (INIS)

    Tarasova, T; Popova, E

    2013-01-01

    In present study, and laser alloying of different steels and laser cladding of Ti and SiC powders mixtures was carried out, and microstructure, as well as microhardness profile and wear properties were examined. Research of the influence of lasers alloying modes on the elastic and plastic characteristics of the surface was conducted. As a result of chemical reactions in the cladded layer, a new phase (TiC) was synthesized during cladding process. The results showed that, in the clad layer, TiC was solidified to form dendrites in the clad zone. Produced coatings have high microhardness values in the upper and middle clad areas, about two time higher than clad matrix microhardness.

  17. Semiconducting properties of oxide and passive films formed on AISI 304 stainless steel and Alloy 600

    Directory of Open Access Journals (Sweden)

    Ferreira M. G. S.

    2002-01-01

    Full Text Available The semiconducting properties of passive films formed on AISI 304 stainless steel and Alloy 600 in borate buffer solution were studied by capacitance (Mott-Schottky approach and photocurrent measurements. Oxide films formed on 304 stainless steel in air at 350 ºC have also been studied. The results obtained show that, in all cases the electronic structure of the films is comparable to that of a p-n heterojunction in which the space charges developed at the metal-film and film-electrolyte interfaces have also to be considered. This is in accordance with analytical results showing that the oxide films are in all cases composed of an inner region rich in chromium oxide and an outer region rich in iron oxide.

  18. Precipitation of Second Phases in High-Interstitial-Alloyed Austenitic Steel

    Science.gov (United States)

    Lee, Tae-Ho; Ha, Heon-Young; Kim, Sung-Joon

    2011-12-01

    The precipitation reaction of an austenitic stainless steel containing N + C was investigated using transmission electron microscopy. The main precipitate formed during isothermal aging at 1123 K (850 °C) was M23C6 carbide, and its morphology gradually changed in a sequence of intergranular (along grain boundary) → cellular (or discontinuous) → intragranular (within grain interior) form with aging time. Irrespective of different morphologies, the M23C6 was consistently related to austenite matrix in accordance with the cube-on-cube orientation relationship. Based on the analysis of electron diffraction, two variants of intragranular M23C6 were identified, and they were related to each other by twin relation. Prolonged aging produced other types of precipitates—the rod-shaped Cr2N and the coarse irregular intermetallic sigma phase. The similarities and differences in precipitation behavior between N only and N + C alloyed austenitic stainless steels are briefly discussed.

  19. Effect of heat-treatment on the hardness and mechanical properties of Boron Alloyed Steel

    Directory of Open Access Journals (Sweden)

    bin Khiyon Mohammad Raffik

    2017-01-01

    Full Text Available In an automotive industry, hot stamped, die quenched structural components have been widely used to provide extra protection against crash intrusion. Boron alloyed steel exhibit limited ductility, but it also promotes improvement in impact performance. This study analyzed the effect of cooling rate on the hardness and energy absorption. Self-quenched specimens were heated to 850°C and cooled in air of room temperature, water at room temperature and cold water. Vickers hardness test and tensile test was then carried out to analyze the effect of different quenching rate. Self-quenched specimens were compared to the properties of the die-quenched specimens obtained from commercial automobile body. Result shows that boron steel with the highest cooling rate has the highest value of hardness but low in strength.

  20. Corrosion behavior of low-alloy steel in the presence of Desulfotomaculum sp

    International Nuclear Information System (INIS)

    Cetin, Demet; Aksu, Mehmet Levent

    2009-01-01

    The objective of this study was to determine the effect of sulfate-reducing Desulfotomaculum sp. bacteria isolated from a crude oil field on the corrosion of low-alloy steel. The corrosion rate and mechanism were determined with the use of Tafel slopes, mass loss method and electrochemical impedance spectroscopy (EIS). The formation of the biofilm and the corrosion products on the steel surface was determined with scanning electron microscopy (SEM) micrographs and energy dispersive X-ray spectra (EDS) analysis. It was observed from the Tafel plots that the corrosion potential exhibited a cathodic shift that verifies an increase in the corrosion rates. The semicircles tended to open at lower frequencies in the Nyquist plots which indicates the rupture of the protective film. The corrosion current density reached its maximum value at the 14th hour after the inoculation and decreased afterwards. This was attributed to the accumulation of corrosion products on the surface.

  1. Effect of heating and deformation conditions on the depth of surface defects in alloyed steel rolling

    International Nuclear Information System (INIS)

    Malygin, R.Z.; Karyakin, B.P.; Grosman, A.B.; Simovskikh, V.N.; Storozhev, V.I.

    1978-01-01

    The effect of heating and deformation conditions on the depth change of artificial defects in the 50 KhFA alloyed steel rolling on the 850 blooming and 450 section mill was studied. Quite a definite regularity in the arrangement of defects (cracks and hairlines) along the circumference of the round steel bar and obvious relation with the defect distribution on the bloom faces are established. Oxidation is shown to diminish defect depth while ingot and billet heating especially on the faces under direct firing. Blooms should be placed in the furnace with 90 deg canting in relation to the faces position while ingot heating. Round rolling must be performed with one or several 45 deg strip cantings. The defect depth for the ingots to be rolled without chipping is set up

  2. Joining of Aluminium Alloy and Steel by Laser Assisted Reactive Wetting

    Science.gov (United States)

    Liedl, Gerhard; Vázquez, Rodrigo Gómez; Murzin, Serguei P.

    2018-03-01

    Compounds of dissimilar materials, like aluminium and steel offer an interesting opportunity for the automotive industry to reduce the weight of a car body. Thermal joining of aluminium and steel leads to the formation of brittle intermetallic compounds, which negatively affects the properties of the welded joint. Amongst others, growth of such intermetallic compounds depends on maximum temperature and on the time at certain temperatures. Laser welding with its narrow well seam and its fast heating and cooling cycles provides an excellent opportunity to obtain an ultrathin diffusion zone. Joining of sheet metal DC01 with aluminium alloy AW6016 has been chosen for research. The performed experimental studies showed that by a variation of the beam power and scanning speed it is possible to obtain an ultrathin diffusion zone with narrow intermetallic interlayers. With the aim of supporting further investigation of laser welding of the respective and other dissimilar pairings a multi-physical simulation model has been developed.

  3. Standard guide for estimating the atmospheric corrosion resistance of low-alloy steels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This guide presents two methods for estimating the atmospheric corrosion resistance of low-alloy weathering steels, such as those described in Specifications A242/A242M, A588/A588M, A606 Type 4, A709/A709M grades 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M. One method gives an estimate of the long-term thickness loss of a steel at a specific site based on results of short-term tests. The other gives an estimate of relative corrosion resistance based on chemical composition. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  4. Partial-Isothermally-Treated Low Alloy Ultrahigh Strength Steel with Martensitic/Bainitic Microstructure

    Science.gov (United States)

    Luo, Quanshun; Kitchen, Matthew; Patel, Vinay; Filleul, Martin; Owens, Dave

    We introduce a new strengthening heat treatment of a Ni-Cr-Mo-V alloyed spring steel by partial isothermal salt-bath and subsequent air-cooling and tempering. Detailed isothermal treatments were made at temperatures below or above the Ms point (230°C). The salt bath time was controlled between 10 and 80 minutes. Through the new treatment, the candidate steel developed ultrahigh tensile strength 2,100 MPa, yield strength 1,800 MPa, elongation 8-10 %, hardness 580-710 HV, and V-notch Charpy toughness 10-12 J. Optical and electron microscopic observations and X-ray diffraction revealed multi-phase microstructures of bainitic/martensitic ferrites, fine carbide precipitates and retained austenite. Carbon partitioning during the bainitic/martensitic transformation was investigated for its remarkable influence on the strengthening mechanism.

  5. Synergistic enhancing effect of N+C alloying on cyclic deformation behaviors in austenitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Kang, J. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Zhang, F.C., E-mail: zfc@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Long, X.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Yang, Z.N. [National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004 (China)

    2014-07-29

    Cyclic plastic and elastic strain controlled deformation behaviors of Mn18Cr7 austenitic steel with N0.6C0.3 synergistic enhancing alloying have been investigated using tension-compression low cycle fatigue and three-point bending high cycle fatigue testing. Results of cyclic deformation characteristic and fatigue damage mechanism have been compared to that in Mn12C1.2 steel. Mn18Cr7N0.6C0.3 steel always shows cyclic softening caused by enhanced planar sliding due to the interaction between N+C and the substitutional atoms as well as the dislocation, which is totally different from cyclic hardening in Mn12C1.2 steel caused by the interaction between C members of C–Mn couples with the dislocation. Enhanced effective stress is obtained due to the solid solution strengthening effect caused by the short range order at low strain amplitude while this effect does not work at high strain amplitude. Internal stress contributes most to the cyclic softening with the increase of strain amplitudes. Significant planar slip characteristic can be observed resulting from low stacking fault energy and high short range order effects in Mn18Cr7N0.6C0.3 steel and finally the parallel or intersecting thin sheets with dislocation tangles separated by dislocation free sheets are obtained with the prolonged cycles under cyclic elastic or plastic strain controlled fatigue testing. There exist amounts of small cracks on the surface of the Mn18Cr7N0.6C0.3 steel because fatigue crack initiation is promoted by the cyclic plastic strain localization. However, the zigzag configuration of the cracks reveals that the fatigue crack propagation is highly inhibited by the planar slip characteristic, which eventually improves the fatigue life.

  6. Optimisation of the mechanical alloying process for odsferritic steels for generation IV reactors application

    International Nuclear Information System (INIS)

    Stanciulescu, M.; Carlan, P.; Mihalache, M.; Abrudeanu, M.

    2016-01-01

    ODS ferritic steels appear as promising materials for fusion and Gen IV fission reactors, offering high temperature performance, corrosion and irradiation resistance and meeting low activation criteria. Mechanical alloying (MA) is a powder metallurgy technique efficient for fabricating advanced materials, and has been used for strengthening structural materials including Fe-Cr alloys. In this paper a high-energy ball mill is used to study the microstructural evolution of 14YW alloy during the mechanical alloying process. The elemental powders are milled at a rotation speed of 250rot/min in cycles of 10min milling and 5min pause, with a ball-to-powder ration of 10:1 and in argon protective atmosphere. After 72 hours milling, the morphology and element distribution of the MA powders is investigated by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis, respectively. It is observed that the particles size increases in the first milling stages and then decreases with the milling time. Changes in the material composition are analysed by X-ray diffraction (DRX). It seems that after milling part of the W remains non-dissolved in the Fe-Cr matrix retarding the solid solution formation. (authors)

  7. Impacts of Modification of Alloying Method on Inclusion Evolution in RH Refining of Silicon Steel.

    Science.gov (United States)

    Li, Fangjie; Li, Huigai; Zheng, Shaobo; You, Jinglin; Han, Ke; Zhai, Qijie

    2017-10-19

    This study explores the effect of introducing additional alloy elements not only in a different order but also at different stages of the Ruhrstahl-Heraeus (RH) process of low-carbon silicon steel production. A more economical method, described as "pre-alloying", has been introduced. The evolution of MnO-FeO inclusions produced by pre-alloying was investigated. Results show that spherical 3FeO·MnO inclusions form first, then shelled FeO·zMnO (z = 0.7-4) inclusions nucleate on the surface of pre-existing 3FeO·MnO. Spherical FeO·zMnO (z = 3-5) is further evolved from shelled 3FeO·MnO by diffusion. Because these MnO-FeO inclusions float up into the slag before degassing, the pre-alloying process does not affect the quality of the melt in the end. Both carbon content and inclusion size conform to industry standards.

  8. Dualism of precipitation morphology in high strength low alloy steel

    International Nuclear Information System (INIS)

    Chih-Yuan, Chen; Chien-Chon, Chen; Jer-Ren, Yang

    2015-01-01

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  9. Dualism of precipitation morphology in high strength low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Chih-Yuan, Chen, E-mail: chen6563@gmail.com [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Chien-Chon, Chen [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Jer-Ren, Yang, E-mail: jryang@ntu.edu.tw [Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2015-02-25

    While the role of microalloying elements on precipitation strengthening in ferrite matrix during austenite/ferrite transformation is quite clear, some uncertainty still exists concerning the variability of the microhardness distribution of ferrite grains in the isothermal holding condition. The objective of the present study was to clarify the intrinsic characteristics of carbide precipitation morphology in the ferrite matrix under different processing temperatures and times and to correlate it with austenite decomposition kinetics to elucidate why a large microhardness distribution occurs at low isothermal holding temperature. Better understanding of carbide precipitation behavior can help researchers to determine the root cause of variation in microhardness distribution, which would allow metallurgists to produce high quality steels. Measurement with a Vickers hardness indenter revealed that, in specimens isothermally held at 625 °C, the range of Vickers hardness distribution was 240–420 after 5 min of isothermal holding, and 270–340 after 60 min. For specimens isothermally held at 725 °C, the range of Vickers hardness distribution was 200–330 for 5 min of isothermal holding, and 200–250 for 60 min. Therefore, the average microhardness decreased with the isothermal holding temperature and time, and a larger range of distribution occurred with short isothermal holding times. Transmission electron microscopy (TEM) images showed that interface precipitation and random precipitation can occur within the same ferrite grain. The reason is that the austenite decomposition rate varies with transformation temperature and time. An excessively fast austenite/ferrite interface movement velocity, which usually happens in small ferrite grains, would cause these ferrite grains with microalloying elements to exceed their solubility. Furthermore, these microalloying elements will be precipitated randomly after isothermal holding at longer times. Consequently, a large

  10. Application of electrochemical impedance spectroscopy to monitor seawater fouling on stainless steels and copper alloys

    International Nuclear Information System (INIS)

    Feron, D.

    1991-01-01

    Electrochemical impedance spectroscopy may be applied to detect and to follow seawater fouling. Experiments have been conducted with natural seawater flowing inside tube-electrodes at temperatures between 30 deg C and 85 deg C. With stainless steel tubes, mineral and organic foulings have been followed; a linear relationship between the dry weight of the organic fouling and its electrical resistance, has been observed. On copper alloy tubes, only mineral deposits have occurred and so have been detected by impedance spectroscopy. (Author). 5 refs., 6 figs

  11. Low Alloy Steel Structures After Welding with Micro-Jet Cooling

    OpenAIRE

    Węgrzyn T.; Piwnik J.; Hadryś D.; Wszołek Ł.

    2017-01-01

    The paper focuses on low alloy steel after innovate welding method with micro-jet cooling. Weld metal deposit (WMD) was carried out for welding and for MIG and MAG welding with micro-jet cooling. This method is very promising mainly due to the high amount of AF (acicular ferrite) and low amount of MAC (self-tempered martensite, retained austenite, carbide) phases in WMD. That structure corresponds with very good mechanical properties, ie. high impact toughness of welds at low temperature. Mic...

  12. Specific energy of cold crack initiation in welding low alloy high-strength steels

    International Nuclear Information System (INIS)

    Brednev, V.I.; Kasatkin, B.S.

    1988-01-01

    Methods for determination of energy spent on cold crack initiation, when testing welded joint samples by the Implant method, are described. Data on the effect of the steel alloying system, cooling rate of welded joints, content of diffusion hydrogen on the critical specific energy spent on the development of local plastic deformation upto cold crack initiation are presented. The value of specific energy spent on cold crack initiation is shown to be by two-three orders lower than the value of impact strength minimum accessible. The possibility to estimate welded joint resistance to cold crack initiation according to the critical specific energy is established

  13. Inertia and friction welding of aluminum alloy 1100 to type 316 stainless steel

    International Nuclear Information System (INIS)

    Perkins, M.A.

    1979-01-01

    The inertia and friction-welding processes were evaluated for joining aluminum alloy 1100-H14 and Type 316 vacuum-induction melted, vacuum-arc remelted (VIM VAR) stainless steel. While both processes consistently produced joints in which the strength exceeded the strength of the aluminum base metal, 100 percent bonding was not reliably achieved with inertia welding. The deficiency points out the need for development of nondestructive testing techniques for this type of joint. Additionally, solid-state volume diffusion did not appear to be a satisfactory explanation for the inertia and friction-welding bonding mechanism

  14. Some microstructural characterisations in a friction stir welded oxide dispersion strengthened ferritic steel alloy

    International Nuclear Information System (INIS)

    Legendre, F.; Poissonnet, S.; Bonnaillie, P.; Boulanger, L.; Forest, L.

    2009-01-01

    The goal of this study is to characterize microstructure of a friction stir welded oxide dispersion strengthened alloy. The welded material is constituted by two sheets of an yttria-dispersion-strengthened PM 2000 ferritic steel. Different areas of the friction stir welded product were analyzed using field emission gun secondary electron microscopy (FEG-SEM) and electron microprobe whereas nanoindentation was used to evaluate mechanical properties. The observed microstructural evolution, including distribution of the yttria dispersoids, after friction stir welding process is discussed and a correlation between the microstructure and the results of nanoindentation tests is established.

  15. Trace element assessment of low-alloy and stainless steels with reference to gamma activity

    International Nuclear Information System (INIS)

    Goddard, A.J.H.; Macmahon, T.D.; Gamberini, D.; Taylor, J.M.; Duggan, F.

    1984-01-01

    In order to predict the long-lived gamma activities leading to radiation exposure during dismantling operations it is necessary to know the likely trace element content of the reactor vessel and internals. This work has been concerned with measuring the elements Ni, Nb, Mo, Co, Ag, Eu, Sm and Ho in steels, with particular reference to light-water reactors. Various steel samples have been provided by organizations in Europe. Analyses have been carried out principally by neutron activation analysis, but also by atomic absorption (AA), inductively coupled plasma (ICP) and secondary ion microprobe spectrometry (SIMS). Analyses for Ni, Mo and Co were straightforward and results agreed with analyses carried out elsewhere. A variety of techniques were employed for Nb; ICP was the most successful and results were confirmed using SIMS. In the case of Ag only flameless AA yielded results for all samples. The low concentration of rare earth elements required the development of a preliminary ion exchange technique. Low-alloy steels examined had Nb concentrations less than 10 ppm. Ag levels in the vicinity of 1 ppm were found in all steel samples, indicating that Ag may be the most significant element at long cooling times. Rare earth concentrations from this and other work indicate that these elements are unlikely to give gamma activities exceeding those of 60 Co, 59 Ni, sup(108m)Ag and 94 Nb activities. Illustrative gamma activity decay calculations using the Origen code are presented

  16. Strain hardening of cold-rolled lean-alloyed metastable ferritic-austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Papula, Suvi [Aalto University School of Engineering, Department of Mechanical Engineering, P.O. Box 14200, FI-00076 Aalto (Finland); Anttila, Severi [Centre for Advanced Steels Research, University of Oulu, P.O. Box 4200, 90014 Oulu (Finland); Talonen, Juho [Outokumpu Oyj, P.O. Box 245, FI-00181 Helsinki (Finland); Sarikka, Teemu; Virkkunen, Iikka; Hänninen, Hannu [Aalto University School of Engineering, Department of Mechanical Engineering, P.O. Box 14200, FI-00076 Aalto (Finland)

    2016-11-20

    Mechanical properties and strain hardening of two pilot-scale lean-alloyed ferritic-austenitic stainless steels having metastable austenite phase, present at 0.50 and 0.30 volume fractions, have been studied by means of tensile testing and nanoindentation. These ferritic-austenitic stainless steels have high strain-hardening capacity, due to the metastable austenite phase, which leads to an improved uniform elongation and higher tensile strength in comparison with most commercial lean duplex stainless steels. According to the results, even as low as 0.30 volume fraction of austenite seems efficient for achieving nearly 40% elongation. The austenite phase is initially the harder phase, and exhibits more strain hardening than the ferrite phase. The rate of strain hardening and the evolution of the martensite phase were found to depend on the loading direction: both are higher when strained in the rolling direction as compared to the transverse direction. Based on the mechanical testing, characterization of the microstructure by optical/electron microscopy, magnetic balance measurements and EBSD texture analysis, this anisotropy in mechanical properties of the cold-rolled metastable ferritic-austenitic stainless steels can be explained by the elongated dual-phase microstructure, fiber reinforcement effect of the harder austenite phase and the presence and interplay of rolling textures in the two phases.

  17. Microstructure evolution of the oxide dispersion strengthened CLAM steel during mechanical alloying process

    Energy Technology Data Exchange (ETDEWEB)

    Song, Liangliang [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Science, Hefei, Anhui, 230031 (China); University of Science and Technology of China, Hefei, Anhui, 230031 (China); Liu, Shaojun, E-mail: shaojun.liu@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Science, Hefei, Anhui, 230031 (China); Mao, Xiaodong [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Science, Hefei, Anhui, 230031 (China)

    2016-11-15

    Highlights: • A nano-sized oxides dispersed ODS-CLAM steel was obtained by MA and HIP. • A minimum saturated grain size of down to 30 nm was achieved by varying the milling time from 0 to 100 h. • Solution of W in the MA powder could be significantly improved by increasing MA rotation speed. - Abstracts: Oxide dispersion strengthened Ferritic/Martensitic steel is considered as one of the most potential structural material for future fusion reactor, owing to its high mechanical properties and good irradiation resistance. The oxide dispersion strengthened China Low Activation Martensitic (ODS-CLAM) steel was fabricated by mechanical alloying (MA) and hot isostatic pressing (HIP). The microstructural evolutions during the process of ball milling and subsequent consolidation were investigated by SEM, XRD and TEM. The results showed that increasing the milling time during the first 36 h milling could effectively decrease the grain size to a value of around 30 nm, over which grain sized remained nearly constant. Increasing the rotation speed promoted the solution of tungsten (W) element obviously and decreased the grain size to a certain degree. Observation on the consolidated and further heat-treated ODS-CLAM steel samples indicated that a martensite microstructure with a high density of nano-particles was achieved.

  18. Comparing the cyclic behavior of concrete cylinders confined by shape memory alloy wire or steel jackets

    International Nuclear Information System (INIS)

    Park, Joonam; Choi, Eunsoo; Kim, Hong-Taek; Park, Kyoungsoo

    2011-01-01

    Shape memory alloy (SMA) wire jackets for concrete are distinct from conventional jackets of steel or fiber reinforced polymer (FRP) since they provide active confinement which can be easily achieved due to the shape memory effect of SMAs. This study uses NiTiNb SMA wires of 1.0 mm diameter to confine concrete cylinders with the dimensions of 300 mm × 150 mm (L × D). The NiTiNb SMAs have a relatively wider temperature hysteresis than NiTi SMAs; thus, they are more suitable for the severe temperature-variation environments to which civil structures are exposed. Steel jackets of passive confinement are also prepared in order to compare the cyclic behavior of actively and passively confined concrete cylinders. For this purpose, monotonic and cyclic compressive loading tests are conducted to obtain axial and circumferential strain. Both strains are used to estimate the volumetric strains of concrete cylinders. Plastic strains from cyclic behavior are also estimated. For the cylinders jacketed by NiTiNb SMA wires, the monotonic axial behavior differs from the envelope of cyclic behavior. The plastic strains of the actively confined concrete show a similar trend to those of passive confinement. This study proposed plastic strain models for concrete confined by SMA wire or steel jackets. For the volumetric strain, the active jackets of NiTiNb SMA wires provide more energy dissipation than the passive jacket of steel

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

    International Nuclear Information System (INIS)

    Ehrnsten, U.; Toivonen, A.; Ivanchenko, M.; Nevdacha, V.; Yagozinskyy, Y.; Haenninen, H.

    2004-01-01

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

  20. EXAMINATION OF THE OXIDATION PROTECTION OF ZINC COATINGS FORMED ON COPPER ALLOYS AND STEEL SUBSTRATES

    International Nuclear Information System (INIS)

    Papazoglou, M.; Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G.; Skolianos, S.

    2010-01-01

    The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steel substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.

  1. Acoustic emission during the elastic-plastic deformation of low alloy reactor pressure vessel steels. I

    International Nuclear Information System (INIS)

    Holt, J.; Goddard, D.J.

    1980-01-01

    Measurements of the acoustic emission behaviour of A533B and C-Mn low alloy reactor pressure vessel steels subjected to uniaxial tensile deformation are described. The effects on the emission activity of the rolling plane orientation and the carbide morphology were examined. Detailed discussions are given of the stress dependence of the emission activity below yield and of its recovery by annealing at the stress relief temperature. It is shown that the dominant emission source is the same in both steels and is associated with inclusions, such as MnS, elongated by the rolling process, the carbide morphology being relatively unimportant. A criterion for the occurrence of an emission is obtained which is directly analogous to the general criterion for yielding. It is also shown that a large fraction, at least, of the emission activity arises from a recoverable process such as localized yielding around inclusions or limited inclusion decohesion and not from inclusion fracture. Low activity in C-Mn steel taken from reactor pressure vessels, previously attributed to spheroidization of carbides, is shown to be due to the limited acoustic recovery of these relatively high sulphur content steels when annealed at the stress relief temperature. It is concluded that the limited amplitudes of these emissions during deformation severely restrict their potential application in practice. (Auth.)

  2. Two-step superconducting transition in Cu-V-Si alloys

    International Nuclear Information System (INIS)

    Sharma, R.G.; Krishna, M.M.; Narlikar, A.V.

    1980-01-01

    Copper ternary alloys containing small amounts of vanadium and silicon exhibit a two-step superconducting resistive transition. The first transition occurs around 17 K, the transition temperature of β-W V 3 Si, followed by a plateau and a second transition around 10 K. The resistivity, however, does not drop to zero down to 2.5 K. Reduction of the wire diameter causes the two transitions to shift to lower temperatures. Complete superconductivity in these specimens is absent for two reasons. Firstly, the superconducting volume fraction present in these alloy-wires is below the threshold given by either the effective-medium theory or the site percolation theory. Secondly, the superconducting phase V 3 Si does not precipitate in copper matrix in a fine structure and the proximity effect does not operate strongly. Annealing causes the superconducting particles to coalesce and grow in size and suppresses the proximity effect and superconductivity further in these alloy wires. (author)

  3. Effect of alloying element partitioning on ferrite hardening in a low alloy ferrite-martensite dual phase steel

    Energy Technology Data Exchange (ETDEWEB)

    Ebrahimian, A., E-mail: ebrahimiana@yahoo.com; Ghasemi Banadkouki, S.S.

    2016-11-20

    In this paper, the effect of carbon and other alloying elements partitioning on ferrite hardening behavior were studied in details using a low alloy AISI4340 ferrite-martensite dual phase (DP) steel. To do so, various re-austenitised samples at 860 °C for 60 min were isothermally heated at 650 °C from 3 to 60 min and then water–quenched to obtain the final ferrite-martensite DP microstructures containing different ferrite and martensite volume fractions. Light and electron microscopic observations were supplemented with electron dispersive spectroscopy (EDS) and nanoindentation tests to explore the localized compositional and hardening variations within ferrite grains in DP samples. The experimental results showed that the ferrite hardness was varied with progress of austenite to ferrite phase transformation in DP samples. In the case of a particular ferrite grain in a particular DP sample, despite a homogeneous distribution of carbon concentration, the ferrite hardness was significantly increased by increasing distance from the central location toward the interfacial α/γ areas. Beside a considerable influence of martensitic phase transformation on adjacent ferrite hardness, these results were rationalized in part to the significant level of Cr and Mo pile-up at α/γ interfaces leading to higher solid solution hardening effect of these regions. The reduction of potential energy developed by attractive interaction between C-Cr and C-Mo couples toward the carbon enriched prior austenite areas were the dominating driving force for pile-up segregation.

  4. Variation of transition temperatures from upper to lower bainites in plain carbon steels

    International Nuclear Information System (INIS)

    Oka, M.; Okamoto, H.

    1995-01-01

    Experimental results and explanations for the transition temperature from upper to lower bainites in carbon steels containing from 0.20 to 1.80 wt%C were presented metallographically and kinematically. The experimental results are summarized as follows: (1) Lower bainite is not formed in steels with less than 0.35 wt%C and no transition from upper to lower bainite occurs. (2) The transition temperature of steels containing from 0.54 to 1.10 %C indicates a constant temperature of 350 C and does not depend on the carbon content. It is important to note that a transition temperature of 350 C corresponds to the Ms temperature of a 0.55%C steel being the boundary of the martensite morphology between a lath and a plate. (3) Transition temperatures of steels with more than 1.10%C decrease along the a line below about 65 C from T 0 -composition line. The bainitic transformation is essentially a kind of the martensitic one and its nucleation site is considered to be a carbon depleted zone in austenite by the thermal fluctuation of carbon atom at an isothermal holding temperature. The supercooling of about 65 C below the T 0 -composition line at the carbon range more than 1.10 wt%C is attributed to the non-chemical free energy for the displacive growth of lower bainite. (orig.)

  5. Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y. [Chungbuk National University, Cheongju (Korea, Republic of)

    2014-07-15

    A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets.

  6. Design of Helical Self-Piercing Rivet for Joining Aluminum Alloy and High-Strength Steel Sheets

    International Nuclear Information System (INIS)

    Kim, W. Y.; Kim, D. B.; Park, J. G; Kim, D. H.; Kim, K. H.; Lee, I. H.; Cho, H. Y.

    2014-01-01

    A self-piercing rivet (SPR) is a mechanical component for joining dissimilar material sheets such as those of aluminum alloy and steel. Unlike conventional rivets, the SPR directly pierces sheets without the need for drilling them beforehand. However, the regular SPR can undergo buckling when it pierces a high-strength steel sheet, warranting the design of a helical SPR. In this study, the joining and forging processes using the helical SPR were simulated using the commercial FEM code, DEFORM-3D. High-tensile-strength steel sheets of different strengths were joined with aluminum alloy sheets using the designed helical SPR. The simulation results were found to agree with the experimental results, validating the optimal design of a helical SPR that can pierce high-strength steel sheets

  7. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    Science.gov (United States)

    Howard, Stanley R [Windsor, SC; Korinko, Paul S [Aiken, SC

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  8. Assessing mechanical properties of the dissimilar metal welding between P92 steels and alloy 617 at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. H.; Hwang, J. H.; Park, Y. S.; Kim, T. M.; Bae, D. H. [Sungkyunkwan University, Suwon (Korea, Republic of); Seo, W. B. [Institute of Mechanical Engineering, Yeungnam University, Daegu (Korea, Republic of); Han, J. W. [School of Mechanical Engineering, Hoseo University, Cheonan (Korea, Republic of)

    2016-10-15

    In this study, a new welding technology of dissimilar materials, Cr-based P92 steels and Ni-based Alloy 617 is introduced and demonstrated to investigate its reliability. Firstly, multi-pass dissimilar metal welding between P92 steel and Alloy 617 was performed using DCEN TIG welding technology, buttering welding technique and a narrow gap groove. After welding, in order to understand characteristics of the dissimilar metal welds, metallurgical micro-structures analysis by optical observation and static tensile strength assessment of the dissimilar welded joints were conducted at 700°C.

  9. Effect of process parameters on formability of laser melting deposited 12CrNi2 alloy steel

    Science.gov (United States)

    Peng, Qian; Dong, Shiyun; Kang, Xueliang; Yan, Shixing; Men, Ping

    2018-03-01

    As a new rapid prototyping technology, the laser melting deposition technology not only has the advantages of fast forming, high efficiency, but also free control in the design and production chain. Therefore, it has drawn extensive attention from community.With the continuous improvement of steel performance requirements, high performance low-carbon alloy steel is gradually integrated into high-tech fields such as aerospace, high-speed train and armored equipment.However, it is necessary to further explore and optimize the difficult process of laser melting deposited alloy steel parts to achieve the performance and shape control.This article took the orthogonal experiment on alloy steel powder by laser melting deposition ,and revealed the influence rule of the laser power, scanning speed, powder gas flow on the quality of the sample than the dilution rate, surface morphology and microstructure analysis were carried out.Finally, under the optimum technological parameters, the Excellent surface quality of the alloy steel forming part with high density, no pore and cracks was obtained.

  10. Crack Resistance of Welded Joints of Pipe Steels of Strength Class K60 of Different Alloying Systems

    Science.gov (United States)

    Tabatchikova, T. I.; Tereshchenko, N. A.; Yakovleva, I. L.; Makovetskii, A. N.; Shander, S. V.

    2018-03-01

    The crack resistance of welded joints of pipe steels of strength class K60 and different alloying systems is studied. The parameter of the crack tip opening displacement (CTOD) is shown to be dependent on the size of the austenite grains and on the morphology of bainite in the superheated region of the heat-affected zone of the weld. The crack resistance is shown to be controllable due to optimization of the alloying system.

  11. Effect of stress on the superconducting transition temperature in indium, indium-alloy, tin, and tin-alloy whisker samples

    International Nuclear Information System (INIS)

    Cook, J.W. Jr.; Davis, W.T.; Chandler, J.H.; Skove, M.J.

    1977-01-01

    The dependence of the superconducting transition temperature (T/sub c/) on stress (sigma) for pure In and Sn samples was found to be in qualitative agreement with earlier work. For convenience T/sub c/ is expressed as a function of the experimentally measured strain (epsilon), which is proportional to sigma. The effect of alloying on the initial dependence of the T/sub c/-vs-epsilon curves, (per. delta T/sub c//per. delta epsilon)/sub epsilon = 0/ = eta, was quite different for the In and Sn alloys. The In samples were alloyed with a maximum of 4.8 at.% Tl, 7.9 at.% Sn, and 6.7 at.% Pd; the Sn samples were alloyed with a maximum of 0.3 at.% Cd, 6.0 at.% In, 0.3 at.% Sb, and 2.2 at.% Bi. The addition of impurities had a large effect on eta for the In alloys, with eta reversing sign for some Sn and Pb alloy contents (chi). The T/sub c/-vs-epsilon curves also became nonlinear for some chi. The possible relationship of the In alloy results to changes in the Fermi surface due to the addition of impurities is discussed. For the Sn alloy samples, there was no change in eta with any impurity. The change in room-temperature resistivity with strain was also measured. There was only a slight decrease in the dependence of resistivity on strain for the In--Sn and In--Pb data and no effect on the In--Tl or Sn alloy data

  12. Tempering of martensitic steel for fasteners: Effects of micro-alloying on microstructure and mechanical property evolution

    OpenAIRE

    Öhlund, C.E.I.C.

    2015-01-01

    The research presented in this thesis aims to deepen our understanding of the effect of micro-alloying on the microstructure and mechanical property evolution during tempering of martensitic steel for fasteners. The ongoing trend of engine down-sizing has led to the need for stronger and more temperature resistant fasteners than currently available according to international standards. A new martensitic fastener steel called KNDS4 has been developed, that combines higher strength with improve...

  13. Application of the radioisotope process when studying the decarbonization of low-alloy multicomponent steels in sodium

    International Nuclear Information System (INIS)

    Pavlinov, L.V.; Evstratov, V.D.

    1982-06-01

    By means of the radioisotope process and the method of a planning matrix for factor experiments quantitative values have been found for the influence of alloys of chromium molybdenum, niobium, vanadium, titanium on the decarbonization of low alloy pearlitic steels in sodium at temperatures of 500 to 800 0 C. It has been proved that of all alloys with a concentration of 1 to 3% Cr, 1 to 2% Mo, 0 to 1% Nb, 0 to 0.25% V, and 0 to 0.25% Ti, which had been studied, the alloys of iron with 1-3% Cr and 1% Mo showed the greatest tendency for decarbonization in sodium where the carbon concentration decreases from 0.01 to 0.02% at the surface. An increase of the concentration of molybdenum and especially of niobium and titanium leads to a decrease of the decarbonization tendency of steel because the surface concentration of carbon remains at the level of 0.08 to 0.09% in alloys which contain up to 1% niobium and in complex alloy steels with up to 1% niobium, 0.25% vanadium, and 0.25% titanium. (orig.) [de

  14. Effect of copper precipitates on the toughness of low alloy steels for pressure boundary components

    International Nuclear Information System (INIS)

    Foehl, J.; Willer, D.; Katerbau, K.H.

    2004-01-01

    The ferritic bainitic steel 15NiCuMoNb5 (WB 36)is widely used for pressure boundary components. Due to the high copper content which leads to precipitation hardening high strength and toughness are characteristic for this type of steel. However, in the initial state, there is still a high amount of dissolved copper in an oversaturated state which makes the steel susceptible to thermal ageing. Ageing and annealing experiments were performed, and the change in microstructure was investigated by small angle neutron scattering (SANS), measurements of the residual electric resistance and hardness measurements. A correlation between micro structural changes and changes in mechanical properties could be established. It could clearly be shown that significant effects on strength and toughness have to be considered when the size of the copper rich precipitates vary in the range from 1.2 to 2.2 nm in radius. The changes in microstructure affect both, the Carpy impact transition temperature and the fracture toughness qualitatively and quantitatively in a similar way. The investigations have contributed to a better understanding of precipitation hardening by copper not only for this type of steel but also for copper containing steels and weld subjected to neutron irradiation. (orig.)

  15. Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties.

    Energy Technology Data Exchange (ETDEWEB)

    Dulikravich, George S.; Sikka, Vinod K.; Muralidharan, G.

    2006-06-01

    The goal of this project was to adapt and use an advanced semi-stochastic algorithm for constrained multiobjective optimization and combine it with experimental testing and verification to determine optimum concentrations of alloying elements in heat-resistant and corrosion-resistant H-series stainless steel alloys that will simultaneously maximize a number of alloy's mechanical and corrosion properties.

  16. Virtual Testing of Composite Structures Made of High Entropy Alloys and Steel

    Directory of Open Access Journals (Sweden)

    Victor Geantă

    2017-11-01

    Full Text Available High entropy alloys (HEA are metallic materials obtained from a mixture of at least five atomic-scale chemical elements. They are characterized by high mechanical strength, good thermal stability and hardenability. AlCrFeCoNi alloys have high compression strength and tensile strength values of 2004 MPa, respectively 1250 MPa and elongation of about 32.7%. These materials can be used to create HEA-steel type composite structures which resist to dynamic deformation during high speed impacts. The paper presents four different composite structures made from a combination of HEA and carbon steel plates, using different joining processes. The numerical simulation of the impact behavior of the composite structures was performed by virtual methods, taking into account the mechanical properties of both materials. For analyzing each constructive variant, three virtual shootings were designed, using a 7.62 × 39 mm cal. incendiary armor-piercing bullet and different impact velocities. The best ballistic behavior was provided by the composite structures obtained by welding and brazing that have good continuity and rigidity. The other composite structures, which do not have good surface adhesion, show high fragmentation risk, because the rear plate can fragment on the axis of shooting due to the combination between the shock waves and the reflected ones. The order of materials in the composite structure has a very important role in decreasing the impact energy.

  17. Femtosecond laser-induced periodic surface structures on steel and titanium alloy for tribological applications

    Science.gov (United States)

    Bonse, J.; Koter, R.; Hartelt, M.; Spaltmann, D.; Pentzien, S.; Höhm, S.; Rosenfeld, A.; Krüger, J.

    2014-10-01

    Laser-induced periodic surface structures (LIPSS, ripples) were generated on stainless steel (100Cr6) and titanium alloy (Ti6Al4V) surfaces upon irradiation with multiple femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas (5 × 5 mm2) covered homogeneously by the nanostructures. The irradiated surface regions were subjected to white light interference microscopy and scanning electron microscopy revealing spatial periods around 600 nm. The tribological performance of the nanostructured surface was characterized by reciprocal sliding against a ball of hardened steel in paraffin oil and in commercial engine oil as lubricants, followed by subsequent inspection of the wear tracks. For specific conditions, on the titanium alloy a significant reduction of the friction coefficient by a factor of more than two was observed on the laser-irradiated (LIPSS-covered) surface when compared to the non-irradiated one, indicating the potential benefit of laser surface structuring for tribological applications.

  18. Effect of solute concentration on grain boundary migration with segregation in stainless steel and model alloys

    Science.gov (United States)

    Kanda, H.; Hashimoto, N.; Takahashi, H.

    The phenomenon of grain boundary migration due to boundary diffusion via vacancies is a well-known process for recrystallization and grain growth during annealing. This phenomenon is known as diffusion-induced grain boundary migration (DIGM) and has been recognized in various binary systems. On the other hand, grain boundary migration often occurs under irradiation. Furthermore, such radiation-induced grain boundary migration (RIGM) gives rise to solute segregation. In order to investigate the RIGM mechanism and the interaction between solutes and point defects during the migration, stainless steel and Ni-Si model alloys were electron-irradiated using a HVEM. RIGM was often observed in stainless steels during irradiation. The migration rate of boundary varied, and three stages of the migration were recognized. At lower temperatures, incubation periods up to the occurrence of the boundary migration were observed prior to first stage. These behaviors were recognized particularly for lower solute containing alloys. From the relation between the migration rates at stage I and inverse temperatures, activation energies for the boundary migration were estimated. In comparison to the activation energy without irradiation, these values were very low. This suggests that the RIGM is caused by the flow of mixed-dumbbells toward the grain boundary. The interaction between solute and point defects and the effective defect concentration generating segregation will be discussed.

  19. Deformation and fracture of Cu alloy-stainless steel layered structures under dynamic loading

    International Nuclear Information System (INIS)

    McCoy, J.H.; Kumar, A.S.

    1998-01-01

    Fracture resistance of the current ITER first wall configuration, a copper alloy-stainless steel layered structure, is a major design issue. The question of dynamic crack propagation into and through the first wall structure is examined using dynamic finite element modeling (FEM). Several layered configurations that incorporate both strain and frictional energy dissipation during the fracture process are considered. With fixed overall specimen geometry, the energy required to extend a precrack is examined as a function of material properties, and the layer structure. It is found that the crack extension energies vary dramatically with the fracture strain of materials, and to a much lesser extent with the number of layers. In addition, it is found that crack propagation through the lower ductility copper alloy layer may be deflected at the stainless steel-copper interface and not result in total fracture of the structure. Although the total energy required is affected only to a small degree by the interface properties, the time to extend the precrack is strongly affected. By making proper selections of the interface and the layered material, crack propagation rates and the possibility of full fracture can be substantially reduced. (orig.)

  20. Statistical analysis of fatigue strain-life data for carbon and low-alloy steels

    International Nuclear Information System (INIS)

    Keisler, J.; Chopra, O.K.; Shack, W.J.

    1994-08-01

    The existing fatigue strain vs. life (S-N) data, foreign and domestic, for carbon and low-alloy steels used in the construction of nuclear power plant components have been compiled and categorized according to material, loading, and environmental conditions. A statistical model has been developed for estimating the effects of the various test conditions on fatigue life. The results of a rigorous statistical analysis have been used to estimate the probability of initiating a fatigue crack. Data in the literature were reviewed to evaluate the effects of size, geometry, and surface finish of a component on its fatigue life. The fatigue S-N curves for components have been determined by applying design margins for size, geometry, and surface finish to crack initiation curves estimated from the model. The significance of the effect of environment on the current Code design curve and on the proposed interim design curves for carbon and low-alloy steels presented in NUREG/CR-5999 is discussed

  1. Research and service experience with environmentally assisted cracking of low-alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Hickling, J. [Electric Power Reasearch Inst., Palo Alto, CA (United States); Seifert, H.P.; Ritter, S. [Paul Scherrer Inst. (Switzerland)

    2005-01-01

    Environmentally assisted cracking (EAC) of carbon and low-alloy steels has been identified as a possible degradation mechanism for pressure vessels and piping in nuclear power plants. Selected aspects of research and service experience with cracking of these materials in high-temperature water are reviewed, with special emphasis on the primary pressure boundary in boiling water reactors. The main factors controlling EAC susceptibility under reactor conditions are discussed with regard to both crack initiation and crack growth. The adequacy and conservatism of the relevant engineering criteria for component design and disposition of detected or postulated flaws are evaluated in the context of recent research results, e.g., on the effects of so-called ''ripple loading'' or of water chemistry transients. Finally, the relevant operating experience over the last 30 years is briefly summarized and compared with the background knowledge which has been accumulated in more recent laboratory experiments. Some of the insights gained in this work may also be of value in improving understanding and prediction of the EAC behavior of carbon and low-alloy steels in certain fossil plant components, if appropriate allowances are made for differences in temperature and water chemistry. (orig.)

  2. High-Strength Low-Alloy Steel Strengthened by Multiply Nanoscale Microstructures

    Science.gov (United States)

    Shen, Y. F.; Zuo, L.

    Recently, we have being focused on improving the strength without sacrificing ductility of High-strength low-alloy (HSLA) steels by designing nanostructures. Several developments have been obtained, summarized as the following three parts: (a) Depressively nanoscale precipitates: A ferritic steel with finely dispersed precipitates reveals a yield strength of 760 MPa, approximately three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels, and its ultimate tensile strength reaches 850 MPa with an elongation-to-failure value of 18%. The finely dispersed TiC precipitates in the matrix provide matrix strengthening. The estimated magnitude of precipitation strengthening is around 458 MPa. The effects of the particle size, particle distribution and intrinsic particle strength have been investigated through dislocation dynamics (DD) simulations. The DD results show that strengthening is not only a function of the density of the nano-scale precipitates but also of their size. (b) Ultrafinely ferritic plate: An interstitial-free (IF) steel sheet with a cold-rolling reduction of 75% shows a high tensile strength (710MPa) while preserving a considerable plastic strain (13%). The ductility recovery with increasing the rolling reduction up to 75% is related with the decreasing both in lamellar spacings and cell blocks sizes. (c) Parallel nano-laminated austenite: A composite microstructure consisting of ferrite, bainitic ferrite (BF) laths and retained austenite (RA) platelets has been found for the steel with a chemical composition of 0.19C-0.30Si-1.76Mn-1.52Al (in mass fraction), processed with annealing and bainitic holding. The sample annealed at 820oC (for 120s) and partitioned at 400oC (for 300s) has the best combination of ultimate tensile strength (UTS, 682 MPa) and elongation to failure ( 70%) with about 26% of BF plates 16% RA in its microstructure.

  3. Hydrogen diffusion and effect on degradation in welded microstructures of creep-resistant low-alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Rhode, Michael

    2016-04-04

    The main challenge for the future is to further increase the power plant thermal efficiency independent of the type of power plant concept, i.e. fossil-fired or nuclear power plant, where the material selection can directly affect reduction of CO{sub 2} emissions. In power plant design, welding is the most applied manufacturing technique in component construction. The necessary weld heat input causes metallurgical changes and phase transitions in the heat affected zone (HAZ) of the base materials and in the deposited weld metal. The weld joint can absorb hydrogen during welding or in later service - This absorption can cause degradation of mechanical properties of the materials, and in certain loading conditions, hydrogen-assisted cold cracks can occur. This cracking phenomenon can appear time delayed due to the temperature dependency of the hydrogen diffusion and the presence of a ''critical'' hydrogen concentration. Additionally, each specific weld microstructure shows a certain hydrogen diffusion and solubility that contribute to susceptibility of the cracking phenomenon. Therefore hydrogen cannot be neglected as possible failure effect, which was identified recently in the case of T24 creep-resistant tube-to-tube weld joints. It is necessary to identify and assess the hydrogen effect in weld joints of low-alloyed steel grades for to improve further early detection of possible failures. For each specific weld joint microstructure, it is necessary to separate the interdependencies between mechanical load and the hydrogen concentration. The diffusivity and solubility must be considered to identify hydrogen quantities in the material at any given time. In this case, the effects of mechanical loading were dealt with independently. For the characterization of the mechanical properties, hydrogen charged tensile specimens were investigated for the base materials and thermally simulated HAZ microstructures. The hydrogen diffusion was characterized

  4. Hydrogen diffusion and effect on degradation in welded microstructures of creep-resistant low-alloyed steels

    International Nuclear Information System (INIS)

    Rhode, Michael

    2016-01-01

    The main challenge for the future is to further increase the power plant thermal efficiency independent of the type of power plant concept, i.e. fossil-fired or nuclear power plant, where the material selection can directly affect reduction of CO 2 emissions. In power plant design, welding is the most applied manufacturing technique in component construction. The necessary weld heat input causes metallurgical changes and phase transitions in the heat affected zone (HAZ) of the base materials and in the deposited weld metal. The weld joint can absorb hydrogen during welding or in later service - This absorption can cause degradation of mechanical properties of the materials, and in certain loading conditions, hydrogen-assisted cold cracks can occur. This cracking phenomenon can appear time delayed due to the temperature dependency of the hydrogen diffusion and the presence of a ''critical'' hydrogen concentration. Additionally, each specific weld microstructure shows a certain hydrogen diffusion and solubility that contribute to susceptibility of the cracking phenomenon. Therefore hydrogen cannot be neglected as possible failure effect, which was identified recently in the case of T24 creep-resistant tube-to-tube weld joints. It is necessary to identify and assess the hydrogen effect in weld joints of low-alloyed steel grades for to improve further early detection of possible failures. For each specific weld joint microstructure, it is necessary to separate the interdependencies between mechanical load and the hydrogen concentration. The diffusivity and solubility must be considered to identify hydrogen quantities in the material at any given time. In this case, the effects of mechanical loading were dealt with independently. For the characterization of the mechanical properties, hydrogen charged tensile specimens were investigated for the base materials and thermally simulated HAZ microstructures. The hydrogen diffusion was characterized with

  5. Impact of medium-range order on the glass transition in liquid Ni-Si alloys

    Science.gov (United States)

    Lü, Y. J.; Entel, P.

    2011-09-01

    We study the thermophysical properties and structure of liquid Ni-Si alloys using molecular dynamics simulations. The liquid Ni-5% and 10%Si alloys crystallize to form the face-centered cubic (Ni) at 900 and 850 K, respectively, and the glass transitions take place in Ni-20% and 25%Si alloys at about 700 K. The temperature-dependent self-diffusion coefficients and viscosities exhibit more pronounced non-Arrhenius behavior with the increase of Si content before phase transitions, indicating the enhanced glass-forming ability. These appearances of thermodynamic properties and phase transitions are found to closely relate to the medium-range order clusters with the defective face-centered cubic structure characterized by both local translational and orientational order. This locally ordered structure tends to be destroyed by the addition of more Si atoms, resulting in a delay of nucleation and even glass transition instead.

  6. Weldability of neutron-irradiated stainless steel and nickel-base alloy

    International Nuclear Information System (INIS)

    Koyabu, Ken; Asano, Kyoichi; Takahashi, Hidenori; Sakamoto, Hiroshi; Kawano, Shohei; Nakamura, Tomomi; Hashimoto, Tsuneyuki; Koshiishi, Masato; Kato, Takahiko; Katsura, Ryoei; Nishimura, Seiji

    2000-01-01

    Degradation of of weldability caused by helium, which is generated by nuclear transmutation irradiated material, is an important issue to be addressed in planning of proactive maintenance of light water reactor core internal components. In this work, the weldability of neutron.irradiated stainless steel and nickel-base alloy, which are major constituting materials for components, was practically evaluated. The weldability was first examined by TIG welding in relation to the weld heat input and helium content using various specimens (made of SUS304 and SUS316L) sampled from reactor internal components. The specimens were neutron irradiated in a boiling water reactor to fluences from 4 x 10 24 to 1.4 x 10 26 n/ m 2 (E> l MeV ), and resulting helium generation ranged from 0.1 to 103 appm. The weld defects were characterized by dye penetrant test and cross-sectional metallography. The weldability of neutron-irradiated stainless steel was shown to be better at lower weld heat input and lower helium content. To evaluate mechanical properties of welded joints, thick plates (20 mm) specimens of SUS304 and Alloy 600 were prepared and irradiated in Japan Material Test Reactor (JMTR). The helium content of the specimens was controlled to range from 0.11 to 1.34 appm selected to determine threshold helium content to weld successfully. The welded joints had multiple passes by TIG welding process at 10 and 20 kJ/cm heat input. The welded joints of thick plate were characterized by dye penetrant test, cross-sectional metallography, tensile test, side bend test and root bend test. It was shown that irradiated stainless steel containing below 0.14 appm of helium could be welded with conventional TIG welding process (heat input below 20 kJ/cm). Nickel-base alloy, which contained as much helium as stainless steel could be welded successfully, could also be welded with conventional TIG welding process, These results served as basis to evaluate the applicability of repair welding to

  7. Microstructure Evolution and Chemical Analysis on Carbon Steels and Fe-Cr-Mo Alloys after FAC Simulation Tests

    International Nuclear Information System (INIS)

    Kim, Seunghyun; Kim, Taeho; Lee, Yun Ju; Kim, Ji Hyun

    2017-01-01

    Flow-accelerated corrosion (FAC) is an environment assisted degradation of structural materials, which usually occurs in pipelines of power plants. There have been many studies to investigate the fundamental mechanism and corresponding countermeasures against FAC, and recently the carbon steels have been replaced by ASTM A 335 P22, which contains approximately 2.2 wt.% of Cr and 1 wt.% of Mo. By enhancing passivity of P22 by Cr, it is reported that FAC rate has been greatly reduced. However, while corrosion behavior of Fe-based alloys is relatively well known, their behavior under high-temperature flowing water is not well investigated. In other words, effects of Cr and its corrosion and oxidation behavior is not clearly revealed. Furthermore, it is known that Mo enhances the pitting corrosion resistance of alloys however its mechanism is not clearly investigated. Recently, replacement of Mo in alloy contents has been widely studied because of the cost of Mo. Carbon steels undergo severe environmental-assisted degradation behavior so called FAC, and as its countermeasure the carbon steel has been replaced by P22 which contains Cr and Mo. It is generally known that Cr and Mo enhances passivity of Fe-based alloys however their corrosion and oxidation behavior has not been fully investigated especially in high-temperature flowing water environments. In this study, we employed HRTEM and synchrotron XAS techniques in order to investigate detailed microstructure evolution and chemical bonding of the commercialized carbon steel and the Fe-Cr-Mo alloys. From the analysis, it is found that while carbon steels exhibit porous oxide P22 exhibit oxide structures with thin Cr-rich oxide and spinel. Therefore, carbon steel undergoes severe FAC compared to P22 however effects of Cr and Mo and their behavior in high-temperature flowing water will be investigated.

  8. Hydrogen degradation of the 26H2MF alloy steel in H2SO4 and hydrocarbon environments

    International Nuclear Information System (INIS)

    Zielinski, A.; Swieczko-Zurek, B.; Michaliak, P.

    2004-01-01

    The Polish 26H2M alloy steel has been subjected to different heat treatment resulting in different microstructure and fracture appearance. The slow strain rate tests have been made on smooth round specimens in diluted sulphuric acid, boiler fuel and used mineral machine oil. The 26H2MF steel has become relatively immune in neutral boiler fuel and mineral oil and been heavily suffered from hydrogen degradation in acidic environment. The results demonstrate that the 26H2MF steel is highly susceptible to hydrogen degradation but in absence of stress raisers the increased hydrogen absorption in hydrocarbons can cause only small loss of its plasticity. (author) >>>

  9. A study of microstructure, quasi-static response, fatigue, deformation and fracture behavior of high strength alloy steels

    Science.gov (United States)

    Kannan, Manigandan

    The history of steel dates back to the 17th century and has been instrumental in the betterment of every aspect of our lives ever since, from the pin that holds the paper together to the Automobile that takes us to our destination steel touches everyone every day. Path breaking improvements in manufacturing techniques, access to advanced machinery and understanding of factors like heat treatment, corrosion resistance have aided in the advancement in the properties of steel in the last few years. In this dissertation document, the results of a study aimed at the influence of alloy chemistry, processing and influence of the quasi static and fatigue behavior of seven alloy steels is discussed. The microstructure of the as-received steel was examined and characterized for the nature and morphology of the grains and the presence of other intrinsic features in the microstructure. The tensile, cyclic fatigue and bending fatigue tests were done on a fully automated closed-loop servo-hydraulic test machine at room temperature. The failed samples of high strength steels were examined in a scanning electron microscope for understanding the fracture behavior, especially the nature of loading be it quasi static, cyclic fatigue or bending fatigue . The quasi static and cyclic fatigue fracture behavior of the steels examined coupled with various factors contributing to failure are briefly discussed in light of the conjoint and mutually interactive influences of intrinsic microstructural effects, nature of loading, and stress (load)-deformation-microstructural interactions.

  10. Impacts of Modification of Alloying Method on Inclusion Evolution in RH Refining of Silicon Steel

    Directory of Open Access Journals (Sweden)

    Fangjie Li

    2017-10-01

    Full Text Available This study explores the effect of introducing additional alloy elements not only in a different order but also at different stages of the Ruhrstahl-Heraeus (RH process of low-carbon silicon steel production. A more economical method, described as “pre-alloying”, has been introduced. The evolution of MnO-FeO inclusions produced by pre-alloying was investigated. Results show that spherical 3FeO·MnO inclusions form first, then shelled FeO·zMnO (z = 0.7–4 inclusions nucleate on the surface of pre-existing 3FeO·MnO. Spherical FeO·zMnO (z = 3–5 is further evolved from shelled 3FeO·MnO by diffusion. Because these MnO-FeO inclusions float up into the slag before degassing, the pre-alloying process does not affect the quality of the melt in the end. Both carbon content and inclusion size conform to industry standards.

  11. Wear of tin coating and Al-Si alloy substrate against carburized steel under mixed lubrication

    Science.gov (United States)

    Wang, Q.; Cheng, H. S.; Fine, M. E.

    1994-04-01

    Tin coatings on Al-Si alloys are widely used in the automotive industries. The soft tin coating and the harder substrate alloy form a tribological system with the advantages of low friction and reasonably high load-bearing capacity. Wear tests of tin coated Al-Si Z332 alloy in conformal contact against carburized 1016 steel have been carried out under mixed lubrications with SAE 10W30 oil to study the wear mechanisms. Two major wear mechanisms, uniform wear of the tin coating due to micro-plowing and spall pitting related to the substrate are found to contribute to the bearing material loss when the fluid lubrication film is relatively thick (Lambda about 1.6). Under conditions of thinner films (Lambda approximately = 0.8), some local coating debonding occurs. The pitting and local coating debounding are closely related to fracture in the substrate. The bonding between silicon and tin seems to be weaker than between aluminum and tin. During wear, oxidation occurs.

  12. Fabrication of Fe-Cr-Mo powder metallurgy steel via a mechanical-alloying process

    Science.gov (United States)

    Park, Jooyoung; Jeong, Gowoon; Kang, Singon; Lee, Seok-Jae; Choi, Hyunjoo

    2015-11-01

    In this study, we employed a mechanical-alloying process to manufacture low-alloy CrL and CrM steel powders that have similar specifications to their water-atomized counterparts. X-ray diffraction showed that Mo and Cr are alloyed in Fe after four cycles of planetary milling for 1 h at 150 RPM with 15-min pauses between the cycles (designated as P2C4 process). Furthermore, the measured powder size was found to be similar to that of the water-atomized counterparts according to both scanning electron microscope images and laser particle size analysis. The samples were sintered at 1120 °C, after which the P2C4-milled CrL showed similar hardness to that of water-atomized CrL, whereas the P2C4-milled CrM showed about 45% lower hardness than that of its water-atomized counterpart. Water-atomized CrM consists of a well-developed lathtype microstructure (bainite or martensite), while a higher fraction of polygonal ferrite is observed in P2C4-milled CrM. This phase difference causes the reduction of hardness in the P2C4-milled CrM, implying that the phase transformation behavior of specimens produced via powder metallurgy is influenced by the powder fabrication method.

  13. Friction welding of A 6061 aluminum alloy and S45C carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Shinoda, T. [Nagoya Univ., Furo-cho, Chikusa-ku, Nagoya (Japan); Kawata, S. [Post Graduate Student, Nagoya Univ., Nagoya (Japan)

    2004-07-01

    Many researches for friction welding of aluminum with either carbon steel or stainless steel have been carried out. From those results, it is concluded that the greatest problem is the formation of brittle intermetallic compounds at weld interface. However, it is not clearly demonstrated the effect of friction welding parameters on the formation of intermetallic compounds. This research purposes are to evaluate the formation of intermetallic compounds and to investigate the effect of friction welding parameters on the strength of welded joint. For these purposes, A6061 aluminum alloy and S45C carbon steel were used with a continuous drive vertical friction welding machine. Tensile test results revealed that the maximum tensile strength was achieved at extremely short friction time and high upset. The joint strength reached 92% of the tensile strength of A6061 base metal. Tensile strength of friction welding was increasing with increasing upset pressure when friction time 1sec. However, tensile properties were deteriorated with increasing friction time. It was observed that the amount of formed intermetallic compound was increasing with increasing friction time at weld interface. Partly formed intermetallic compound on weld interface were identified when friction time 1 sec. However, intermetallic compound layer were severely developed with longer friction time at weld interface. It was concluded that intermetallic compound layer deteriorated the tensile properties of weld joints. (orig.)

  14. Effects of LWR coolant environments on fatigue design curves of carbon and low-alloy steels

    International Nuclear Information System (INIS)

    Chopra, O.K.; Shack, W.J.

    1998-03-01

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the code specify fatigue design curves for structural materials. While effects of reactor coolant environments are not explicitly addressed by the design curves, test data indicate that the Code fatigue curves may not always be adequate in coolant environments. This report summarizes work performed by Argonne National Laboratory on fatigue of carbon and low-alloy steels in light water reactor (LWR) environments. The existing fatigue S-N data have been evaluated to establish the effects of various material and loading variables such as steel type, dissolved oxygen level, strain range, strain rate, temperature, orientation, and sulfur content on the fatigue life of these steels. Statistical models have been developed for estimating the fatigue S-N curves as a function of material, loading, and environmental variables. The results have been used to estimate the probability of fatigue cracking of reactor components. The different methods for incorporating the effects of LWR coolant environments on the ASME Code fatigue design curves are presented

  15. Galvanic corrosion between carbon steel 1018 and Alloy 600 in crevice with boric acid solution

    International Nuclear Information System (INIS)

    Kim, Dong Jin; Kim, Hong Pyo; Kim, Joung Soo; Machonald, Digby D.

    2005-01-01

    This work dealt with the evaluation of galvanic corrosion rate in a corrosion cell having annular gap of 0.5 mm between carbon steel 1018 and alloy 600 as a function of temperature and boron concentration. Temperature and boron concentration were ranged from 110 to 300 .deg. C and 2000∼10000 ppm, respectively. After the operating temperature of the corrosion cell where the electrolyte was injected was attained at setting temperature, galvanic coupling was made and at the same time galvanic current was measured. The galvanic corrosion rate decreased with time, which was described by corrosion product such as protective film as well as boric acid deposit formed on the carbon steel with time. From the galvanic current obtained as a function of temperature and boron concentration, it was found that the galvanic corrosion rate decreased with temperature while the corrosion rate increased with boron concentration. The experimental results obtained from galvanic corrosion measurement were explained by adhesive property of corrosion product such as protective film, boric acid deposit formed on the carbon steel wall and dehydration of boric acid to be slightly soluble boric acid phase. Moreover the galvanic corrosion rate calculated using initial galvanic coupling current instead of steady state coupling current was remarked, which could give us relatively closer galvanic corrosion rate to real pressurized water reactor

  16. Metallurgical/Alloy Optimization of High Strength and Wear Resistant Structural Quench and Tempered Steels

    Science.gov (United States)

    Stalheim, Douglas G.; Peimao, Fu; Linhao, Gu; Yongqing, Zhang

    Structural steels with yield strength requirements greater or equal to 690 MPa can be produced through controlled recrystallization hot rolling coupled with precipitation strengthening or purposeful heat treatment through quench and tempering (Q&T). High strength structural steel and wear/abrasion resistant requirements greater or equal to 360 Brinell hardness (BHN) are produced by the development of microstructures of tempered lower bainite and/or martensite through the Q&T process. While these Q&T microstructures can produce very high strengths and hardness levels making them ideal for 690 MPa plus yield strength or wear/abrasion resistant applications, they lack toughness/ductility and hence are very brittle and prone to cracking. While tempering the microstructures helps in improving the toughness/ductility and reducing the brittleness, strength and hardness can be sacrificed. In addition, these steels typically consist of alloy designs containing boron with carbon equivalents (CE) greater than 0.50 to achieve the desired microstructures. The higher CE has a negative influence on weldability.

  17. Threshold velocity for environmentally-assisted cracking in low alloy steels

    International Nuclear Information System (INIS)

    Wire, G.L.; Kandra, J.T.

    1997-01-01

    Environmentally Assisted Cracking (EAC) in low alloy steels is generally believed to be activated by dissolution of MnS inclusions at the crack tip in high temperature LWR environments. EAC is the increase of fatigue crack growth rate of up to 40 to 100 times the rate in air that occurs in high temperature LWR environments. A steady state theory developed by Combrade, suggested that EAC will initiate only above a critical crack velocity and cease below this same velocity. A range of about twenty in critical crack tip velocities was invoked by Combrade, et al., to describe data available at that time. This range was attributed to exposure of additional sulfides above and below the crack plane. However, direct measurements of exposed sulfide densities on cracked specimens were performed herein and the results rule out significant additional sulfide exposure as a plausible explanation. Alternatively, it is proposed herein that localized EAC starting at large sulfide clusters reduces the calculated threshold velocity from the value predicted for a uniform distribution of sulfides. Calculations are compared with experimental results where the threshold velocity has been measured, and the predicted wide range of threshold values for steels of similar sulfur content but varying sulfide morphology is observed. The threshold velocity decreases with the increasing maximum sulfide particle size, qualitatively consistent with the theory. The calculation provides a basis for a conservative minimum velocity threshold tied directly to the steel sulfur level, in cases where no details of sulfide distribution are known

  18. Friction stir weld assisted diffusion bonding of 5754 aluminum alloy to coated high strength steels

    International Nuclear Information System (INIS)

    Haghshenas, M.; Abdel-Gwad, A.; Omran, A.M.; Gökçe, B.; Sahraeinejad, S.; Gerlich, A.P.

    2014-01-01

    Highlights: • Successful lap joints of Al 5754 sheet to coated DP600 and 22MnB5 steels. • Negligible effect of welding speed on mechanical properties of Al 5754/22MnB5 joints. • Lower strength of Al 5754/22MnB5 joints compared with Al 5754/DP600 joints. - Abstract: In the present paper friction stir-induced diffusion bonding is used for joining sheets of 5754 aluminum alloy to coated high strength steels (DP600 and 22MnB5) by promoting diffusion bonding in an overlap configuration. Mechanical performance and microstructures of joints were analyzed by overlap shear testing, metallography, and X-ray diffraction. Our results show that the strength of joint is dependent upon tool travel speed and the depth of the tool pin relative to the steel surface. The thickness and types of intermetallic compounds formed at the interface play a significant role in achieving a joint with optimum performance. That is, the formation of high aluminum composition intermetallic compounds (i.e. Al 5 Fe 2 ) at the interface of the friction stir lap joint appeared to have a more negative effect on joint strength compared to the presence of high iron composition intermetallic phases (i.e. FeAl). This is in agreement with previously reported findings that FeAl intermetallic can improve the fracture toughness and interface strength in Al/St joints

  19. Influence of carbon on the formation of the surface layer in the process of electroerosion alloying of steel with tungsten

    Science.gov (United States)

    Vasil'eva, E. V.; Bochkov, V. E.; Mikheev, É. A.; Lyakishev, V. A.; Afanas'eva, T. N.

    1983-10-01

    With an increase in carbon content in the steel being treated, the thickness of the alloyed layer increases and its microhardness also increases. The carbon exerts a deoxidizing action on the layer being formed and promotes a reduction in the threshold of deerosion and also additional strengthening of the layer as the result of the formation of binary η-carbides.

  20. 75 FR 20342 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty...

    Science.gov (United States)

    2010-04-19

    ... covered in this review, but was covered in a previous review or the original less-than-fair-value (LTFV... investigation. See Final Determination of Sales at Less Than Fair Value: Circular Welded Non- Alloy Steel Pipe... for framing and support members for reconstruction or load-bearing purposes in the construction...

  1. 76 FR 77770 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty...

    Science.gov (United States)

    2011-12-14

    ... previous review or the original less-than-fair-value (LTFV) investigation, the cash deposit rate will... Determination of Sales at Less Than Fair Value: Circular Welded Non-Alloy Steel Pipe From Mexico, 57 FR 42953... structural pipe tubing used for framing and support members for reconstruction or load-bearing purposes in...

  2. Tempering of martensitic steel for fasteners : Effects of micro-alloying on microstructure and mechanical property evolution

    NARCIS (Netherlands)

    Öhlund, C.E.I.C.

    2015-01-01

    The research presented in this thesis aims to deepen our understanding of the effect of micro-alloying on the microstructure and mechanical property evolution during tempering of martensitic steel for fasteners. The ongoing trend of engine down-sizing has led to the need for stronger and more

  3. Computer simulation of the influence of the alloying elements on secondary hardness of the high-speed steels

    International Nuclear Information System (INIS)

    Dobrzanski, L.A.; Sitek, W.; Zaclona, J.

    2004-01-01

    The paper presents the method of modelling of high-speed steels' (HSS) properties, being basing on chemical composition and heat treatment parameters, employing neural networks. An example of its application possibility the computer simulation was made of the influence of the particular alloying elements on hardness and obtained results are presented. (author)

  4. The failure behavior of duplex 316 L steel-TA6V titanium alloy spherical pressure vessels

    International Nuclear Information System (INIS)

    Miannay, D.

    1980-05-01

    The purpose of this paper is to compare the experimental residual stresses of spherical vessels made of TA6V alloy which exhibits plasticity before failure in toughness testing and cracked with several configurations, with stresses estimated according to the afore mentioned theories. An internal austenitic 316 L steel is used to prevent 'leak before break' [fr

  5. Microstructural evolution at the overlap zones of 12Cr martensitic stainless steel laser alloyed with TiC

    CSIR Research Space (South Africa)

    Adebiyi, DI

    2014-09-01

    Full Text Available are not obtainable in the single tracks. X12CrNiMo steel has been laser alloyed with TiC using a 4.4 kW continuous wave (CW) Nd:YAG laser. The process parameters were first optimised after which they were kept constant for overlap ratios of 50% and 75%. The depths...

  6. 75 FR 69050 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's...

    Science.gov (United States)

    2010-11-10

    ... amended (``the Act''), that an industry in the United States is threatened with material injury by reason... case is based on the threat of material injury and is not accompanied by a finding that injury would... Alloy Steel Standard, Line, and Pressure Pipe From the People's Republic of China: Amended Final...

  7. 75 FR 69052 - Certain Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From the People's...

    Science.gov (United States)

    2010-11-10

    ... threatened with material injury by reason of imports of seamless pipe from the PRC. According to section 736... that determination is based on the threat of material injury and is not accompanied by a finding that... Alloy Steel Standard, Line, and Pressure Pipe From the People's Republic of China: Amended Final...

  8. 78 FR 34342 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results and Partial Rescission of...

    Science.gov (United States)

    2013-06-07

    ... Welded Non-Alloy Steel Pipe from Brazil, the Republic of Korea (Korea), Mexico, and Venezuela and... Proceedings: Assessment of Antidumping Duties, 68 FR 23954 (May 6, 2003) (reseller policy). This clarification... antidumping duties in accordance with the reseller policy. Cash Deposit Requirements The following cash...

  9. 76 FR 49437 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Preliminary Results of Antidumping Duty...

    Science.gov (United States)

    2011-08-10

    ... Non-Alloy Steel Pipe from Brazil, the Republic of Korea (Korea), Mexico, and Venezuela and Amendment... 23954 (May 6, 2003) (Assessment Policy Notice). Because ``as entered'' liquidation instructions do not... assessment'' regulation on May 6, 2003. See Assessment Policy Notice. This clarification will apply to POR...

  10. SCC propagation and cessation behavior near the fusion boundary of dissimilar weld joint with Ni-based weld metal and low alloy steel

    International Nuclear Information System (INIS)

    Ishizawa, Makoto; Abe, Hiroshi; Watanabe, Yutaka

    2009-01-01

    The purpose of this study is to investigate the following items focused on the microstructure near the fusion boundary of dissimilar weld joint with Ni-based weld metal and low alloy steel; (1) Microstructural characteristics near the fusion boundary, (2) Dominant factor that makes crack retardation near the fusion boundary. Main conclusions can be summarized as follows; (1) From the results of CBB tests, it has been understood that the low alloy steel has no SCC susceptibility and that there is a difference in oxidation behavior between high and low sulfur containing low alloy steel, (2) In Alloy182/LAS sample, most of crack tips were located at the fusion boundary. It has been thought that crack become less active when crack reach at fusion boundary, (3) It has been suggested that the dominant factor of crack retardation is low SCC susceptibility of low alloy steel in high temperature water. (author)

  11. Microstructural and hardness investigations on a dissimilar metal weld between low alloy steel and Alloy 82 weld metal

    International Nuclear Information System (INIS)

    Chen, Z.R.; Lu, Y.H.; Ding, X.F.; Shoji, T.

    2016-01-01

    The investigation on microstructure and hardness at the fusion boundary (FB) region of a dissimilar metal weld (DMW) between low alloy steel (LAS) A508-III and Alloy 82 weld metal (WM) was carried out. The results indicated that there were two kinds of FBs, martensite FB and sharp FB, with obvious different microstructures, alternately distributed in the same FB. The martensite FB region had a gradual change of elemental concentration across FB, columnar WM grains with high length/width ratios, a thick martensite layer and a wide heat affected zone (HAZ) with large prior austenite grains. By comparison, the sharp FB region had a relatively sharp change of elemental concentration across the FB, WM grains with low length/width ratios and a narrow HAZ with smaller prior austenite grains. The martensite possessed a K-S orientation relationship with WM grains, while no orientation relationship was found between the HAZ grains and WM grains at the sharp FB. Compared with sharp FB there were much more Σ3 boundaries in the HAZ beside martensite FB. The hardness maximum of the martensite FB was much higher than that of the sharp FB, which was attributed to the martensite layer at the martensite FB. - Highlights: •Martensite and sharp FBs with different microstructures were found in the same FB. •There were high length/width-ratio WM grains and a wide HAZ beside martensite FB. •There were low length/width-ratio WM grains and a narrow HAZ beside sharp FB. •Compared with sharp FB, there were much more Σ3 boundaries in HAZ of martensite FB. •Hardness maximium of martensite FB was much higher than that of sharp FB.

  12. Thermodynamic analysis of transition pressure of δ-stabilized binary plutonium alloys

    International Nuclear Information System (INIS)

    Wang Qinghui

    1992-01-01

    The transformation of δ-stabilized binary plutonium alloys to α-Pu was studies by thermodynamic analysis. A transition pressure-composition equation which can characterize the high pressure transformation from δ to α was derived. Values calculated by the equation and values measured by experiments of published references have the same tendency. the following facts can be explained properly by this equation. (1)The transformation pressure increases linearly with the amount of an alloying element. (2) The slope of the plot of transformation pressure versus composition of δ-Pu alloys is inversely proportional to the minimum amount of solute required to retain δ-phase at room temperature and pressure. (3) Curves showing the relationship between transformation pressure and composition of various δ-stabilized binary alloys interact at the same point of zero solute (transformation pressure axis). In addition, some transformation pressures from δ to α of δ-stabilized alloys are predicted by using the modified theoretical equation

  13. Rapid solidification growth mode transitions in Al-Si alloys by dynamic transmission electron microscopy

    International Nuclear Information System (INIS)

    Roehling, John D.; Coughlin, Daniel R.; Gibbs, John W.; Baldwin, J. Kevin; Mertens, James C.E.; Campbell, Geoffrey H.; Clarke, Amy J.; McKeown, Joseph T.

    2017-01-01

    In situ dynamic transmission electron microscope (DTEM) imaging of Al-Si thin-film alloys was performed to investigate rapid solidification behavior. Solidification of alloys with compositions from 1 to 15 atomic percent Si was imaged during pulsed laser melting and subsequent solidification. Solely α-Al solidification was observed in Al-1Si and Al-3Si alloys, and solely kinetically modified eutectic growth was observed in Al-6Si and Al-9Si alloys. A transition in the solidification mode in eutectic and hypereutectic alloys (Al-12Si and Al-15Si) from nucleated α-Al dendrites at lower solidification velocities to planar eutectic growth at higher solidification velocities was observed, departing from trends previously seen in laser-track melting experiments. Comparisons of the growth modes and corresponding velocities are compared with previous solidification models, and implications regarding the models are discussed.

  14. Corrosion of high Ni-Cr alloys and Type 304L stainless steel in HNO3-HF

    International Nuclear Information System (INIS)

    Ondrejcin, R.S.; McLaughlin, B.D.

    1980-04-01

    Nineteen alloys were evaluated as possible materials of construction for steam heating coils, the dissolver vessel, and the off-gas system of proposed facilities to process thorium and uranium fuels. Commercially available alloys were found that are satisfactory for all applications. With thorium fuel, which requires HNO 3 -HF for dissolution, the best alloy for service at 130 0 C when complexing agents for fluoride are used is Inconel 690; with no complexing agents at 130 0 C, Inconel 671 is best. At 95 0 C, six other alloys tested would be adequate: Haynes 25, Ferralium, Inconel 625, Type 304L stainless steel, Incoloy 825, and Haynes 20 (in order of decreasing preference); based on composition, six untested alloys would also be adequate. The ions most effective in reducing fluoride corrosion were the complexing agents Zr 4+ and Th 4+ ; Al 3+ was less effective. With uranium fuel, modestly priced Type 304L stainless steel is adequate. Corrosion will be most severe in HNO 3 -HF used occasionally for flushing and in solutions of HNO 3 and corrosion products (ferric and dichromate ions). HF corrosion can be minimized by complexing the fluoride ion and by passivation of the steel with strong nitric acid. Corrosion caused by corrosion products can be minimized by operating at lower temperatures

  15. Master curve characterization of the fracture toughness behavior in SA508 Gr.4N low alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Hyoung, E-mail: shirimp@kaist.ac.k [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Kim, Min-Chul; Lee, Bong-Sang [Nuclear Materials Research Division, KAERI, Daejeon 305-353 (Korea, Republic of); Wee, Dang-Moon [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2010-08-15

    The fracture toughness properties of the tempered martensitic SA508 Gr.4N Ni-Mo-Cr low alloy steel for reactor pressure vessels were investigated by using the master curve concept. These results were compared to those of the bainitic SA508 Gr.3 Mn-Mo-Ni low alloy steel, which is a commercial RPV material. The fracture toughness tests were conducted by 3-point bending with pre-cracked charpy (PCVN) specimens according to the ASTM E1921-09c standard method. The temperature dependency of the fracture toughness was steeper than those predicted by the standard master curve, while the bainitic SA508 Gr.3 steel fitted well with the standard prediction. In order to properly evaluate the fracture toughness of the Gr.4N steels, the exponential coefficient of the master curve equation was changed and the modified curve was applied to the fracture toughness test results of model alloys that have various chemical compositions. It was found that the modified curve provided a better description for the overall fracture toughness behavior and adequate T{sub 0} determination for the tempered martensitic SA508 Gr.4N steels.

  16. Overload effects on a ferritic-baintic steel and a cast aluminium alloy: two very different behaviours

    Energy Technology Data Exchange (ETDEWEB)

    Saintier, N. [Arts et Metiers Paris Tech, I2M, UMR CNRS, Universite Bordeaux 1, Talene Cedex (France); El Dsoki, C.; Kaufmann, H.; Sonsino, C.M. [Fraunhofer-Institute for Structural Durability and System Reliability LBF, Darmstadt (Germany); Dumas, C. [RENAULT, Technocentre, Guyancourt Cedex (France); Voellmecke, F.J. [BORBET GmbH, Hallenberg-Hesborn (Germany); Palin-Luc, T.; Bidonard, H.

    2011-10-15

    Load controlled fatigue tests were performed up to 10{sup 7} cycles on flat notched specimens (K{sub t} = 2.5) under constant amplitude and variable amplitude loadings with and without periodical overloads. Two materials are studied: a ferritic-bainitic steel (HE400M steel) and a cast aluminium alloy (AlSi7Mg0.3). These materials have a very different cyclic behaviour: the steel exhibits cyclic strain softening whereas the Al alloy shows cyclic strain hardening. The fatigue tests show that, for the steel, periodical overload applications reduce significantly the fatigue life for fully reversed load ratio (R{sub {sigma}} = -1), while they have no influence under pulsating loading (R{sub {sigma}} = 0). For the Al alloy overloads have an effect (fatigue life decreasing) only for variable amplitude loadings. The detrimental effect of overloads on the steel is due to ratcheting at the notch root which evolution is overload's dependent. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Effects of the phase fractions on the carbide morphologies, Charpy and tensile properties in SA508 Gr.4N High Strength Low Alloy RPV Steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Gyu; Wee, Dang Moon [KAIST, Daejeon (Korea, Republic of); Kim, Min Chul; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2011-05-15

    To improve the strength and toughness of RPV (reactor pressure vessel) steels for nuclear power plants, an effective way is the change of material specification from tempered bainitic SA508 Gr.3 Mn-Mo-Ni low alloy steel into tempered martensitic/bainitic SA508 Gr.4N Ni-Cr-Mo low alloy steel. It is known that the phase fractions of martensitic/bainitic steels are very sensitive to the austenitizing cooling rates. Kim reported that there are large differences of austenitizing cooling rates between the surface and the center locations in RPV due to its thickness of 250mm. Hence, the martensite/bainite fractions would be changed in different locations, and it would affect the microstructure and mechanical properties in Ni-Cr-Mo low alloy steel. These results may lead to inhomogeneous characteristics after austenitizing. Therefore, it is necessary to evaluate the changes of microstructure and mechanical properties with varying phase fractions in Ni-Cr-Mo low alloy steel. In this study, the effects of martensite/bainite fractions on microstructure and mechanical properties in Ni-Cr-Mo low alloy steel were examined. The changes in phase fractions of Ni-Cr-Mo low alloy steel with different cooling rates were analyzed, and then the phase fractions were correlated with its microstructural observation and mechanical properties

  18. Effect of cooling rate during solidification of Sn-9Zn lead-free solder alloy on its microstructure, tensile strength and ductile-brittle transition temperature

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu, K.N., E-mail: prabhukn_2002@yahoo.co.in [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025 (India); Deshapande, Parashuram; Satyanarayan [Department of Metallurgical and Materials Engineering, National Institute of Technology Karnataka, Surathkal, Mangalore 575 025 (India)

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer Effect of cooling rate on tensile and impact properties of Sn-9Zn alloy was assessed. Black-Right-Pointing-Pointer Both DBTT and UTS of the solder alloy increased with increase in cooling rate. Black-Right-Pointing-Pointer An optimum cooling rate during solidification would minimize DBTT and maximize UTS. - Abstract: Solidification rate is an important variable during processing of materials, including soldering, involving solidification. The rate of solidification controls the metallurgical microstructure at the solder joint and hence the mechanical properties. A high tensile strength and a lower ductile-brittle transition temperature are necessary for reliability of solder joints in electronic circuits. Hence in the present work, the effect of cooling rate during solidification on microstructure, impact and tensile properties of Sn-9Zn lead-free solder alloy was investigated. Four different cooling media (copper and stainless steel moulds, air and furnace cooling) were used for solidification to achieve different cooling rates. Solder alloy solidified in copper mould exhibited higher cooling rate as compared to other cooling media. The microstructure is refined as the cooling rate was increased from 0.03 to 25 Degree-Sign C/s. With increase in cooling rate it was observed that the size of Zn flakes became finer and distributed uniformly throughout the matrix. Ductile-to-brittle transition temperature (DBTT) of the solder alloy increased with increase in cooling rate. Fractured surfaces of impact test specimens showed cleavage like appearance and river like pattern at very low temperatures and dimple like appearance at higher temperatures. The tensile strength of the solder alloy solidified in Cu and stainless moulds were higher as compared to air and furnace cooled samples. It is therefore suggested that the cooling rate during solidification of the solder alloy should be optimum to maximize the strength and minimize the

  19. Effect of cooling rate during solidification of Sn–9Zn lead-free solder alloy on its microstructure, tensile strength and ductile–brittle transition temperature

    International Nuclear Information System (INIS)

    Prabhu, K.N.; Deshapande, Parashuram; Satyanarayan

    2012-01-01

    Highlights: ► Effect of cooling rate on tensile and impact properties of Sn–9Zn alloy was assessed. ► Both DBTT and UTS of the solder alloy increased with increase in cooling rate. ► An optimum cooling rate during solidification would minimize DBTT and maximize UTS. - Abstract: Solidification rate is an important variable during processing of materials, including soldering, involving solidification. The rate of solidification controls the metallurgical microstructure at the solder joint and hence the mechanical properties. A high tensile strength and a lower ductile–brittle transition temperature are necessary for reliability of solder joints in electronic circuits. Hence in the present work, the effect of cooling rate during solidification on microstructure, impact and tensile properties of Sn–9Zn lead-free solder alloy was investigated. Four different cooling media (copper and stainless steel moulds, air and furnace cooling) were used for solidification to achieve different cooling rates. Solder alloy solidified in copper mould exhibited higher cooling rate as compared to other cooling media. The microstructure is refined as the cooling rate was increased from 0.03 to 25 °C/s. With increase in cooling rate it was observed that the size of Zn flakes became finer and distributed uniformly throughout the matrix. Ductile-to-brittle transition temperature (DBTT) of the solder alloy increased with increase in cooling rate. Fractured surfaces of impact test specimens showed cleavage like appearance and river like pattern at very low temperatures and dimple like appearance at higher temperatures. The tensile strength of the solder alloy solidified in Cu and stainless moulds were higher as compared to air and furnace cooled samples. It is therefore suggested that the cooling rate during solidification of the solder alloy should be optimum to maximize the strength and minimize the DBTT.

  20. Computational Design of a Novel Medium-Carbon, Low-Alloy Steel Microalloyed with Niobium

    Science.gov (United States)

    Javaheri, Vahid; Nyyssönen, Tuomo; Grande, Bjørnar; Porter, David

    2018-04-01

    The design of a new steel with specific properties is always challenging owing to the complex interactions of many variables. In this work, this challenge is dealt with by combining metallurgical principles with computational thermodynamics and kinetics to design a novel steel composition suitable for thermomechanical processing and induction heat treatment to achieve a hardness level in excess of 600 HV with the potential for good fracture toughness. CALPHAD-based packages for the thermodynamics and kinetics of phase transformations and diffusion, namely Thermo-Calc® and JMatPro®, have been combined with an interdendritic segregation tool (IDS) to optimize the contents of chromium, molybdenum and niobium in a proposed medium-carbon low-manganese steel composition. Important factors taken into account in the modeling and optimization were hardenability and as-quenched hardness, grain refinement and alloying cost. For further investigations and verification, the designed composition, i.e., in wt.% 0.40C, 0.20Si, 0.25Mn, 0.90Cr, 0.50Mo, was cast with two nominal levels of Nb: 0 and 0.012 wt.%. The results showed that an addition of Nb decreases the austenite grain size during casting and after slab reheating prior to hot rolling. Validation experiments showed that the predicted properties, i.e., hardness, hardenability and level of segregation, for the designed composition were realistic. It is also demonstrated that the applied procedure could be useful in reducing the number of experiments required for developing compositions for other new steels.

  1. Surface Alloying of SUS 321 Chromium-Nickel Steel by an Electron-Plasma Process

    Science.gov (United States)

    Ivanov, Yu. F.; Teresov, A. D.; Petrikova, E. A.; Krysina, O. V.; Ivanova, O. V.; Shugurov, V. V.; Moskvin, P. V.

    2017-07-01

    The mechanisms of forming nanostructured, nanophase layers are revealed and analyzed in austenitic steel subjected to surface alloying using an electron-plasma process. Nanostructured, nanophase layers up to 30 μm in thickness were formed by melting of the film/substrate system with an electron beam generated by a SOLO facility (Institute of High Current Electronics, SB RAS), Tomsk), which ensured crystallization and subsequent quenching at the cooling rates within the range 105-108 K/s. The surface was modified with structural stainless steel specimens (SUS 321 steel). The film/substrate system (film thickness 0.5 μm) was formed by a plasma-assisted vacuum-arc process by evaporating a cathode made from a sintered pseudoalloy of the following composition: Zr - 6 at.% Ti - 6 at.% Cu. The film deposition was performed in a QUINTA facility equipped with a PINK hot-cathode plasma source and DI-100 arc evaporators with accelerated cooling of the process cathode, which allowed reducing the size and fraction of the droplet phase in the deposited film. It is found that melting of the film/substrate system (Zr-Ti-Cu)/(SUS 321 steel) using a high-intensity pulsed electron beam followed by the high-rate crystallization is accompanied by the formation of α-iron cellular crystallization structure and precipitation of Cr2Zr, Cr3C2 and TiC particles on the cell boundaries, which as a whole allowed increasing microhardness by a factor of 1.3, Young's modulus - by a factor of 1.2, wear resistance - by a factor of 2.7, while achieving a three-fold reduction in the friction coefficient.

  2. Cessation of environmentally-assisted cracking in a low-alloy steel: Theoretical analysis

    International Nuclear Information System (INIS)

    Wire, G.L.

    1997-01-01

    Environmentally Assisted Cracking (EAC) can cause increases in fatigue crack growth rates of 40 to 100 times the rate in air for low alloy steels. The increased rates can lead to very large predicted crack growth. EAC is activated by a critical level of dissolved sulfides at the crack tip. Sulfide inclusions (MnS) in the steel produce corrosive sulfides in solution following exposure by a growing crack. In stagnant, low oxygen water conditions considered here, diffusion is the dominant mass transport mechanism acting to change the sulfide concentration within the crack. The average crack tip velocity is below the level required to produce the critical crack tip sulfide ion concentration required for EAC. Crack extension analyses also consider the breakthrough of large, hypothetical embedded defects with the attendant large freshly exposed sulfide inventory. Combrade et al. noted that a large inventory of undissolved metallurgical sulfides on crack flanks could trigger EAC, but did not quantify the effects. Diffusion analysis is extended herein to cover breakthrough of embedded defects with large sulfide inventories. The mass transport via diffusion is limited by the sulfide solubility. As a result, deep cracks in high sulfur steels are predicted to retain undissolved sulfides for extended but finite periods of time t diss which increase with the crack length and the metallurgical sulfide content in the steel. The analysis shows that the duration of EAC is limited to t diss providing V eac , the crack tip velocity associated with EAC is less than V In , the crack tip velocity below which EAC will not occur in an initially sulfide free crack. This condition on V eac need only be met for a short time following crack cleanup to turn off EAC. The predicted crack extension due to limited duration of EAC is a small fraction of the initial embedded defect size and would not greatly change calculated crack depths

  3. Effect of mechanical alloying atmosphere on the microstructure and Charpy impact properties of an ODS ferritic steel

    International Nuclear Information System (INIS)

    Oksiuta, Z.; Baluc, N.

    2009-01-01

    Two types of oxide dispersion strengthened (ODS) ferritic steels, with the composition of Fe-14Cr-2W-0.3Ti-0.3Y 2 O 3 (in weight percent), have been produced by mechanically alloying elemental powders of Fe, Cr, W, and Ti with Y 2 O 3 particles either in argon atmosphere or in hydrogen atmosphere, degassing at various temperatures, and compacting the mechanically alloyed powders by hot isostatic pressing. It was found in particular that mechanical alloying in hydrogen yields a significant reduction in oxygen content in the materials, a lower dislocation density, and a strong improvement in the fast fracture properties of the ODS ferritic steels, as measured by Charpy impact tests.

  4. Zr-based conversion layer on Zn-Al-Mg alloy coated steel sheets: insights into the formation mechanism

    International Nuclear Information System (INIS)

    Lostak, Thomas; Maljusch, Artjom; Klink, Björn; Krebs, Stefan; Kimpel, Matthias; Flock, Jörg; Schulz, Stephan; Schuhmann, Wolfgang

    2014-01-01

    Zr-based conversion layers are considered as environmentally friendly alternatives replacing trication phosphatation in the automotive industry. Based on excellent electronic barrier properties they provide an effective corrosion protection of the metallic substrate. In this work, thin protective layers were grown on novel Zn-Al-Mg alloy coated steel sheets by increasing the local pH-value at the sample surface leading to deposition of a Zr-based conversion layer. For this purpose Zn-Al-Mg alloy (ZM) coated steel sheets were treated in an aqueous model conversion solution containing well-defined amounts of hexafluorozirconic acid (H 2 ZrF 6 ) and characterized after different immersion times with SKPFM and field emission SEM (FE-SEM)/EDX techniques. A deposition mechanism of Zr-based conversion coatings on microstructural heterogeneous Zn-Al-Mg alloy surfaces was proposed

  5. Tribological Behavior of Babbitt Alloy Rubbing Against Si3N4 and Steel Under Dry Friction Condition

    Science.gov (United States)

    Ji, Xianbing; Chen, Yinxia

    2016-03-01

    The tribological behavior of Babbitt alloy rubbing with Si3N4 ball and steel ball with various sliding speeds at dry friction condition was investigated. It was found that B88 alloy rubbing with Si3N4 ball and steel ball possesses a low sliding wear resistance at dry friction. The wear rate is above 10-4 mm3/Nm, and the friction coefficient is from 0.2 to 0.4. At low sliding speed of 0.05-0.1 m/s, the mainly wear mechanisms are microgroove and fatigue wear, while at high sliding speed of 0.5 m/s, the wear mechanisms depend on plastic deformation and delamination. The high wear rate indicates that it is needed to prevent Babbitt alloy from working at dry friction conditions, while the low friction coefficient suggests that it is not easy to the occurrence of cold weld.

  6. Effect of Temperature on the Toughness of Locally Manufactured Low Alloy Steel SUP9 Used for Manufacturing Leaf Springs

    Directory of Open Access Journals (Sweden)

    Muhammad Ishaque Abro

    2011-10-01

    Full Text Available The effect of heat treatment on locally manufactured low alloy steel grade SUP9 most frequently used in making leaf springs for automobiles was studied. While for determination of toughness and hardness Charpy impact testing machine and Rockwell hardness tester were used. The cryogenic test temperatures were achieved by soaking the samples in liquid nitrogen and temperature was measured using digital thermometer capable of reading the temperature from -40-200oC. Hardening, tempering and austempering treatments were conducted using muffle furnace and salt bath furnace. After heat treatment samples were quenched in oil. The results of present work confirmed that toughness and hardness are inversely related with each other and are highly dependent on the type of heat treatment employed. Highest toughness was measured after austempering at 450oC. Effect of test temperature revealed that toughness of the samples increased significantly with decreasing temperature. DBTT (Ductile to Brittle Transition Temperature of the austempered samples was observed at -10oC, whereas, that of tempered samples could not be determined. Based on the test results authors wish to recommend the 600oC tempering temperature in place of 450oC where normally tempering is practiced in Alwin industry Karachi during manufacturing of leaf spring.

  7. Electrochemical oxidation of zirconium alloys in pre-transition and post-transition kinetic regimes at corrosion in electrolyte solutions

    International Nuclear Information System (INIS)

    Barkov, A.A.; Shavshin, V.M.

    1986-01-01

    With the aim of investigation on oxidation of zirconium alloys (Zr+2.5% Nb) the critical thickness of beginning of spalling of froming oxide films in HCl and NHO 3 aqueous solutions was evaluated by coulometry with accelerated procedure. Some variants of predeposition of modificated oxide coatings are proposed increase pre-transition regime time and to decrease corrosion during post-transition regime. Increase in agressivity of solutions (addition of 1 vol.% HF) and UV irradiation are found to increase 3-4 times pre-transition period

  8. Ductile and brittle transition behavior of titanium alloys in ultra-precision machining.

    Science.gov (United States)

    Yip, W S; To, S

    2018-03-02

    Titanium alloys are extensively applied in biomedical industries due to their excellent material properties. However, they are recognized as difficult to cut materials due to their low thermal conductivity, which induces a complexity to their deformation mechanisms and restricts precise productions. This paper presents a new observation about the removal regime of titanium alloys. The experimental results, including the chip formation, thrust force signal and surface profile, showed that there was a critical cutting distance to achieve better surface integrity of machined surface. The machined areas with better surface roughness were located before the clear transition point, defining as the ductile to brittle transition. The machined area at the brittle region displayed the fracture deformation which showed cracks on the surface edge. The relationship between depth of cut and the ductile to brittle transaction behavior of titanium alloys in ultra-precision machining(UPM) was also revealed in this study, it showed that the ductile to brittle transaction behavior of titanium alloys occurred mainly at relatively small depth of cut. The study firstly defines the ductile to brittle transition behavior of titanium alloys in UPM, contributing the information of ductile machining as an optimal machining condition for precise productions of titanium alloys.

  9. Investigation of steel to dielectric transition using microminiature eddy-current converter

    Directory of Open Access Journals (Sweden)

    Malikov Vladimir

    2018-01-01

    Full Text Available The research aims to develop a microminiature converter for electrical steel investigation. The research topic is considered relevant due to the need for evaluation and forecasting of safe operating life of electric steel products. The authors determined the capability to study steel characteristics at different depths based on variations of eddy-current converter amplitude at the steel-dielectric boundary. A microminiature transformer-type converter was designed, which enables to perform local investigations of ferromagnetic materials using eddy-current method based on local studies of the steel electrical conductivity. Having the designed converter as a basis, a hardware-software complex was built to perform experimental studies of steel at the interface boundary. A system was developed for automated converter relocation above the studied object at a specified velocity. Test results are reported for a specimen with continuous and discrete measurements taken at different frequencies. Response dependence of eddy-current converter was found to demonstrate non-linear behavior at steel to dielectric transition. The effect of gap between the eddy-current converter and the test object is investigated.

  10. Low alloy steels that minimize the hydrogen-carbide reaction. Final technical report, October 1, 1978-September 30, 1979. Part I

    Energy Technology Data Exchange (ETDEWEB)

    Kar, R. J.; Parker, E. R.; Zackay, V. F.

    1979-01-01

    This report presents results obtained during the first year of a research program to investigate important metallurgical parameters that control the reactions of hydrogen with carbides in steels. Preliminary work included a detailed literature review of th phenomenon of decarburization and methane bubble formation in steels and a suitable experimental technique for investigating hydrogen attack in laboratory conditions was established. Detailed microstructural-mechanical property evaluations were carried out on two series of alloys; the first was based on a plain carbon steel to which binary and ternary alloy additions were made to vary the carbide structure and morphology and assess these effects on the observed hydrogen attack resistance. The second group of steels consisted of commercial Mn-Mo-Ni (A 533 B) and Cr-Mo (A 542 type) steels and their alloy modifications, with a view towards developing steels with improved hydrogen attack resistance.

  11. The integrity of 9Cr-1Mo to stainless steel transition joints in AGR steam generators

    International Nuclear Information System (INIS)

    James, D.W.; Neumann, P.; Soo, J.

    1982-01-01

    The metallurgical aspects of the transition joint between 9Cr-1Mo and 316 stainless steel boiler tube sections are reviewed. A large minimum superheat margin (106 0 C) between the dryout zone and the 9Cr-1Mo to stainless steel transition joint was specified in the original design to eliminate the risk of wetting the stainless steel which is susceptible to stress corrosion cracking. However, small defects were discovered in the welds between the 9Cr-1Mo and Sanicro (72%Ni-16%Cr-10%Fe) transition piece, resulting from dilution of the weld pool by nickel from the transition piece. This led to the possibility of weld failure as a result of creep crack growth in service, and any significant reduction in operating temperature would mean that the large superheat margin could not be sustained. The creep properties of the joints, together with the transition joint temperature distribution, enabled tube failure rates to be determined as a function of operating temperature. A probabilistic model was developed so that the transition joint could be operated within a temperature 'window', the lower temperature limit being determined by stress corrosion considerations and the upper limit being set by creep rate limitations. This allows full load performance from the boilers throughout the anticipated life of the plant. (author)

  12. A FeNiMnC alloy with strain glass transition

    Directory of Open Access Journals (Sweden)

    Hui Ma

    2018-02-01

    Full Text Available Recent experimental and theoretical investigations suggested that doping sufficient point defects into a normal ferroelastic/martensitic alloy systems could lead to a frozen disordered state of local lattice strains (nanomartensite domains, thereby suppressing the long-range strain-ordering martensitic transition. In this study, we attempt to explore the possibility of developing novel ferrous Elinvar alloys by replacing nickel with carbon and manganese as dopant species. A nominal Fe89Ni5Mn4.6C1.4 alloy was prepared by argon arc melting, and XRD, DSC, DMA and TEM techniques were employed to characterize the strain glass transition signatures, such as invariance in average structure, frequency dispersion in dynamic mechanical properties (storage modulus and internal friction and the formation of nanosized strain domains. It is indicated that doping of Ni, Mn and C suppresses γ→α long-range strain-ordering martensitic transformation in Fe89Ni5Mn4.6C1.4 alloy, generating randomly distributed nanosized domains by strain glass transition. Keywords: Strain glass transition, Elinvar alloys, Point defects, Nanosized domains

  13. Intermartensitic transitions in Ni-Mn-Fe-Cu-Ga Heusler alloys

    International Nuclear Information System (INIS)

    Khan, Mahmud; Gautam, Bhoj; Pathak, Arjun; Dubenko, Igor; Stadler, Shane; Ali, Naushad

    2008-01-01

    A series of Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga Heusler alloys have been investigated by means of x-ray diffraction, magnetizations, thermal expansion, and electrical resistivity measurements. In Ni 2 Mn 0.75 Cu 0.25 Ga, martensitic and ferromagnetic transitions occur at the same temperature. Partial substitution of Mn by Fe results in a decrease of the martensitic transition temperature, T M , and an increase of the ferromagnetic transition temperature, T C , resulting in separation of the two transitions. In addition to the martensitic transition, complete thermoelastic intermartensitic transformations have been observed in the Fe doped Ni 2 Mn 0.75-x Fe x Cu 0.25 Ga samples with x>0.04. An unusual transition is observed in the alloy with x = 0.04. The magnetization curve as a function of increasing temperature shows only one first-order transition in the temperature range 5-400 K, which is identified as a typical coupled magnetostructural martensitic transformation. The magnetization curve as a function of decreasing temperature shows three different transitions, which are characterized as the ferromagnetic transition, the martensitic transition and the intermartensitic transition.

  14. Magnetic susceptibility of transition metal alloys with a hcp structure

    International Nuclear Information System (INIS)

    Volkenshtejn, N.V.; Galoshina, Eh.V.; Gorina, N.B.; Korenovskij, N.L.; Polyakova, V.P.; Savitskij, E.M.

    1978-01-01

    The angular dependence of the magnetic susceptibility of single crystals of Ru-Nb, Re-W and Os-Re alloys is investigated in the region of the hexagonal closely packed structure. The spin susceptibility is estimated on the basis of available data on the electron specific heat. The principal values of the orbital component of the susceptibility are determined under the assumption of isotopy of the spin contribution to the susceptibility. In Ru-Nb alloys the magnitudes of the orbital contributions and the susceptibility anisotropy are found to increase; in Re-W the spin contribution is noticeably greater whereas the orbital susceptibility is smaller, as is the anistropy. In the Os-Re alloy the orbital contributions increase and the susceptibility anisotropy is constant. It is suggested that the addition of the second component changes the overlapping of the d-electron wave functions

  15. Microstructures and mechanical properties of magnesium alloy and stainless steel weld-joint made by friction stir lap welding

    International Nuclear Information System (INIS)

    Wei, Yanni; Li, Jinglong; Xiong, Jiangtao; Huang, Fu; Zhang, Fusheng

    2012-01-01

    Highlights: → Friction stir lap welding technology with cutting pin was successfully employed to form lap joint of magnesium and steel. → The cutting pin made the lower steel participate in deformation and the interface was no longer flat. → A saw-toothed structure formed due to a mechanical mixing of the magnesium and steel was found at the interface. → A high-strength joint was produced which fractured in the magnesium side. -- Abstract: Friction stir lap welding was conducted on soft/hard metals. A welding tool was designed with a cutting pin of rotary burr made of tungsten carbide, which makes the stirring pin possible to penetrate and cut the surface layer of the hard metal. Magnesium alloy AZ31 and stainless steel SUS302 were chosen as soft/hard base metals. The structures of the joining interface were analyzed by scanning electron microscopy (SEM). The joining strength was evaluated by tensile shear test. The results showed that flower-like interfacial morphologies were presented with steel flashes and scraps, which formed bonding mechanisms of nail effect by long steel flashes, zipper effect by saw-tooth structure and metallurgical bonding. The shear strength of the lap joint falls around the shear strength of butt joint of friction stir welded magnesium alloy.

  16. Microstructure and mechanical characterization of friction stir welded high strength low alloy steels

    Energy Technology Data Exchange (ETDEWEB)

    Ramesh, R., E-mail: rameshsmit@gmail.com [Department of Mechanical Engineering, PSG College of Technology, Coimbatore 641004, Tamilnadu (India); Dinaharan, I., E-mail: dinaweld2009@gmail.com [Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg 2006, Gauteng (South Africa); Kumar, Ravi, E-mail: nvrk@iitm.ac.in [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamilnadu (India); Akinlabi, E.T., E-mail: etakinlabi@uj.ac.za [Department of Mechanical Engineering Science, University of Johannesburg, Auckland Park Kingsway Campus, Johannesburg 2006, Gauteng (South Africa)

    2017-02-27

    Friction stir welding (FSW) is a promising technique to join HSLA steels without the problems encountered during fusion based welding processes. In the present work, 3 mm thick HSLA plates were successfully welded using FSW. A tool made of tungsten-rhenium alloy was used in this work. The relationship between microstructure and tensile strength was studied under various welding conditions i.e. change in traverse speed (57–97 mm/min). The microstructure of the weld nugget revealed the presence of upper bainite and fine ferrite phases. The amount of upper bainite reduced with increase in traverse speed. EBSD images showed a reducing trend for grain size. The details of hardness, tensile strength and bending test were reported.

  17. Electrochemical and passive behaviour of tin alloyed ferritic stainless steel in concrete environment

    Science.gov (United States)

    Luo, Hong; Su, Huaizhi; Li, Baosong; Ying, Guobing

    2018-05-01

    In the present work, the electrochemical behavior and semiconducting properties of a tin alloyed ferritic stainless steel in simulated concrete solution in presence of NaCl were estimated by conventional electrochemical methods such as potentiodynamic polarization, electrochemical impedance spectroscopy, and capacitance measurement (Mott-Schottky approach). The surface passive film was analyzed by X-ray photoelectron spectroscopy. The results revealed a good agreement between pitting corrosion, electrochemical behaviour, and electronic properties. The p and n-type bilayer structure passive film were observed. The increase of Sn4+ oxide species in the passive film shows no beneficial effects on the pitting corrosion. In addition, the dehydration of the passive film was further discussed.

  18. Deposition of Co-Ti alloy on mild steel substrate using laser cladding

    International Nuclear Information System (INIS)

    Alemohammad, Hamidreza; Esmaeili, Shahrzad; Toyserkani, Ehsan

    2007-01-01

    Laser cladding of a Co-Ti alloy on a mild steel substrate is studied. Premixed powders with the composition of 85 wt% cobalt and 15 wt% titanium are pre-placed on the substrate and a moving laser beam at different velocities is used to produce clad layers well bounded to the substrate. Characteristics of the clad are investigated using optical microscopy, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and microhardness tests. The results reveal that the intermetallic phase TiCo 3 and β (i.e. fcc) cobalt are formed in the clad layer. The clad layer can also have major dilution from the substrate depending on the laser scanning velocity. It is observed that a finer microstructure is achievable with higher laser velocities whereas higher hardness is achieved using lower velocities. The latter is due to the formation of a larger fraction of TiCo 3 phase

  19. Microstructure and mechanical characterization of friction stir welded high strength low alloy steels

    International Nuclear Information System (INIS)

    Ramesh, R.; Dinaharan, I.; Kumar, Ravi; Akinlabi, E.T.

    2017-01-01

    Friction stir welding (FSW) is a promising technique to join HSLA steels without the problems encountered during fusion based welding processes. In the present work, 3 mm thick HSLA plates were successfully welded using FSW. A tool made of tungsten-rhenium alloy was used in this work. The relationship between microstructure and tensile strength was studied under various welding conditions i.e. change in traverse speed (57–97 mm/min). The microstructure of the weld nugget revealed the presence of upper bainite and fine ferrite phases. The amount of upper bainite reduced with increase in traverse speed. EBSD images showed a reducing trend for grain size. The details of hardness, tensile strength and bending test were reported.

  20. Multiphase Microstructure in a Metastability-Assisted Medium Carbon Alloy Steel

    Science.gov (United States)

    Liu, Cheng; Cui, Xixi; Yang, Chen

    2018-05-01

    A medium carbon alloy steel is processed by austenizing at 900 °C for 30 min, then rapid quenching into a patented quenching liquid and holding at 170 °C for 5 min, finally isothermally holding at 250 °C for different times. The morphology and mechanical properties are performed by using optical microscopy and scanning electron microscopy. A multiphase microstructure characterized by a mixture of lenticular prior martensite (PM), fine needle bainitic ferrite and filmy retained austenite (RA) is obtained. It is found that the PM formed firstly upon quenching can accelerate the subsequent bainitic transformation and promote refinement of multiphase colonies. The results show that an optimum mechanical property of a 4000.9 MPa bending strength and a 2030 MPa tensile strength is achieved at 250 °C for 120 min, which is attributed to the multiphase microstructural characteristics and a high product of the volume fraction of RA and the carbon content of austenite.

  1. Hydrogen permeation inhibition by zinc-nickel alloy plating on steel XC68

    International Nuclear Information System (INIS)

    El Hajjami, A.; Gigandet, M.P.; De Petris-Wery, M.; Catonne, J.C.; Duprat, J.J.; Thiery, L.; Raulin, F.; Starck, B.; Remy, P.

    2008-01-01

    The inhibition of hydrogen permeation and barrier effect by zinc-nickel plating was investigated using the Devanathan-Stachurski permeation technique. The hydrogen permeation and hydrogen diffusion for the zinc-nickel (12-15%) plating on steel XC68 is compared with zinc and nickel. Hydrogen permeation and hydrogen diffusion were followed as functions of time at current density applied (cathodic side) and potential permanent (anodic side). The hydrogen permeation inhibition for zinc-nickel is intermediate to that of nickel and zinc. This inhibition was due to nickel-rich layer effects at the Zn-Ni alloy/substrate interface, is shown by GDOES. Zinc-nickel plating inhibited the hydrogen diffusion greater as compared to zinc. This diffusion resistance was due to the barrier effect caused by the nickel which is present at the interface and transformed the hydrogen atomic to Ni 2 H compound, as shown by GIXRD.

  2. Hydrogen permeation inhibition by zinc-nickel alloy plating on steel XC68

    Energy Technology Data Exchange (ETDEWEB)

    El Hajjami, A. [Institut UTINAM, UMR CNRS 6213, Sonochimie et Reactivite des Surfaces, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France); Coventya S.A.S., 51 rue Pierre, 92588 Clichy Cedex (France); Gigandet, M.P. [Institut UTINAM, UMR CNRS 6213, Sonochimie et Reactivite des Surfaces, Universite de Franche-Comte, 16 route de Gray, 25030 Besancon Cedex (France)], E-mail: marie-pierre.gigandet@univ-fcomte.fr; De Petris-Wery, M. [Institut Universitaire de Technologie d' Orsay, Universite Paris XI, Plateau de Moulon, 91400 Orsay (France); Catonne, J.C. [Professeur Honoraire du Conservatoire national des arts et metiers (CNAM), Paris (France); Duprat, J.J.; Thiery, L.; Raulin, F. [Coventya S.A.S., 51 rue Pierre, 92588 Clichy Cedex (France); Starck, B.; Remy, P. [Lisi Automotive, 28 faubourg de Belfort, BP 19, 90101 Delle Cedex (France)

    2008-12-30

    The inhibition of hydrogen permeation and barrier effect by zinc-nickel plating was investigated using the Devanathan-Stachurski permeation technique. The hydrogen permeation and hydrogen diffusion for the zinc-nickel (12-15%) plating on steel XC68 is compared with zinc and nickel. Hydrogen permeation and hydrogen diffusion were followed as functions of time at current density applied (cathodic side) and potential permanent (anodic side). The hydrogen permeation inhibition for zinc-nickel is intermediate to that of nickel and zinc. This inhibition was due to nickel-rich layer effects at the Zn-Ni alloy/substrate interface, is shown by GDOES. Zinc-nickel plating inhibited the hydrogen diffusion greater as compared to zinc. This diffusion resistance was due to the barrier effect caused by the nickel which is present at the interface and transformed the hydrogen atomic to Ni{sub 2}H compound, as shown by GIXRD.

  3. Comparison of Solid and Hollow Torque Transducer Shaft Response in a High Alloy Stainless Steel

    Science.gov (United States)

    Milby, Christopher L.; Hecox, Bryan G.; Wiewel, Joseph L.; Boley, Mark S.

    2007-03-01

    Recent investigations of the torque transducer response function (ambient field signal versus applied torque or shear stress) have been conducted in a 13% chromium and 8% nickel stainless steel alloy in both the hollow shaft and solid shaft configuration. An understanding of both is needed for applications with differing yield strength and hardness requirements. Axial hysteresis measurements conducted before and after heat treatment exhibited little difference in coercivity and retentivity between the two sample types. However, the field mapping and transducer sensitivity studies showed the hollow shaft configuration to have a far superior degree of polarization in the sensory region and to exhibit an enhanced sensitivity, especially after heat treatment. This is most likely due to its more efficient provision of closed circumferential geometry for the field lines and improved grain alignment during heat treatment.

  4. Statistical analysis of fatigue strain-life data for carbon and low-alloy steels

    International Nuclear Information System (INIS)

    Keisler, J.; Chopra, O.K.

    1995-03-01

    The existing fatigue strain vs life (S-N) data, foreign and domestic, for carbon and low-alloy steels used in the construction of nuclear power plant components have been compiled and categorized according to material, loading, and environmental conditions. A statistical model has been developed for estimating the effects of the various test conditions on fatigue life. The results of a rigorous statistical analysis have been used to estimate the probability of initiating a fatigue crack. Data in the literature were reviewed to evaluate the effects of size, geometry, and surface finish of a component on its fatigue life. The fatigue S-N curves for components have been determined by applying design margins for size, geometry, and surface finish to crack initiation curves estimated from the model

  5. Overlapping phase transformations on tempering of a low-alloy steel

    International Nuclear Information System (INIS)

    Valencia Morales, E; Galeano Alvarez, N.J; Vega Leiva, J; Castellanos L M; Villar C E; Antiquera Munoz J; Hernandez R J

    2006-01-01

    The kinetics of precipitation of the primary and independent carbides during tempering of a low-alloy steel are characterized by the application of the Kinetic Theory of the Overlapping Phase Transformations(KTOPT). It is based on the Avrami model and considers two simultaneous precipitation processes. The present set-up allows us to calculate the exponent of the Avrami equation for simultaneous reactions at different rates. Only the dilatometry curves on tempering are required. According to this new formulation, the treatment of the dilatometry records showed different mechanisms of nucleation and growth of the primary and independent carbides. These results are in agreement with the thin foil electron micrographs and hardness tests of the thermally treated samples (au)

  6. Ricochet of a tungsten heavy alloy long-rod projectile from deformable steel plates

    International Nuclear Information System (INIS)

    Lee, Woong; Lee, Heon-Joo; Shin, Hyunho

    2002-01-01

    Ricochet of a tungsten heavy alloy long-rod projectile from oblique steel plates with a finite thickness was investigated numerically using a full three-dimensional explicit finite element method. Three distinctive regimes resulting from oblique impact depending on the obliquity, namely simple ricochet, critical ricochet and target perforation, were investigated in detail. Critical ricochet angles were calculated for various impact velocities and strengths of the target plates. It was predicted that critical ricochet angle increases with decreasing impact velocities and that higher ricochet angles were expected if higher strength target materials are employed. Numerical predictions were compared with existing two-dimensional analytical models. Experiments were also carried out and the results supported the predictions of the numerical analysis

  7. Analysis of copper alloy to stainless steel bonded panels for ITER first wall applications

    International Nuclear Information System (INIS)

    Stubbins, J.F.; Kurath, P.; Drockelman, D.; Li, G.; Thomas, B.G.; Morgan, G.D.; McAfee, J.

    1995-01-01

    The mechanical performance of bi-layer copper alloy (Gildcop CuA115) to 316L stainless steel panels was examined. This work was to analyze potential bonding methodologies for the fabrication of ITER first wall structures, to verify the bond integrity of the fabricated panels, and to establish some mechanical performance parameters for panel structural performance. Two bonding routes were examined: explosively bonding and hot isostatically pressed (HIP) bonding. Following fabrication, the panels were mechanically loaded in tensile and fatigue tests. The mechanical performance test verified that the bond integrity was excellent, and that the primary mode of failure of the bonded panels was related to failure in the base materials rather than lack of adequate bond strength

  8. Predicting the creep life and failure mode of low-alloy steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Brear, J.M.; Middleton, C.J.; Aplin, P.F. [ERA Technology Ltd., Leatherhead (United Kingdom)

    1998-12-31

    This presentation reviews and consolidates experience gained through a number of research projects and practical plant assessments in predicting both the life and the likely failure mode and location in low alloy steel weldments. The approach adopted begins with the recognition that the relative strength difference between the microstructural regions is a key factor controlling both life and failure location. Practical methods based on hardness measurement and adaptable to differing weld geometries are presented and evidence for correlations between hardness ratio, damage accumulation and strain development is discussed. Predictor diagrams relating weld life and failure location to the service conditions and the hardness of the individual microstructural constituents are suggested and comments are given on the implications for identifying the circumstances in which Type IV cracking is to be expected. (orig.) 6 refs.

  9. Deposition of Co-Ti alloy on mild steel substrate using laser cladding

    Energy Technology Data Exchange (ETDEWEB)

    Alemohammad, Hamidreza [University of Waterloo, Department of Mechanical and Mechatronics Engineering, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada)], E-mail: shalemoh@engmail.uwaterloo.ca; Esmaeili, Shahrzad [University of Waterloo, Department of Mechanical and Mechatronics Engineering, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada); Toyserkani, Ehsan [University of Waterloo, Department of Mechanical and Mechatronics Engineering, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada)

    2007-05-15

    Laser cladding of a Co-Ti alloy on a mild steel substrate is studied. Premixed powders with the composition of 85 wt% cobalt and 15 wt% titanium are pre-placed on the substrate and a moving laser beam at different velocities is used to produce clad layers well bounded to the substrate. Characteristics of the clad are investigated using optical microscopy, X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and microhardness tests. The results reveal that the intermetallic phase TiCo{sub 3} and {beta} (i.e. fcc) cobalt are formed in the clad layer. The clad layer can also have major dilution from the substrate depending on the laser scanning velocity. It is observed that a finer microstructure is achievable with higher laser velocities whereas higher hardness is achieved using lower velocities. The latter is due to the formation of a larger fraction of TiCo{sub 3} phase.

  10. Predicting the creep life and failure mode of low-alloy steel weldments

    Energy Technology Data Exchange (ETDEWEB)

    Brear, J M; Middleton, C J; Aplin, P F [ERA Technology Ltd., Leatherhead (United Kingdom)

    1999-12-31

    This presentation reviews and consolidates experience gained through a number of research projects and practical plant assessments in predicting both the life and the likely failure mode and location in low alloy steel weldments. The approach adopted begins with the recognition that the relative strength difference between the microstructural regions is a key factor controlling both life and failure location. Practical methods based on hardness measurement and adaptable to differing weld geometries are presented and evidence for correlations between hardness ratio, damage accumulation and strain development is discussed. Predictor diagrams relating weld life and failure location to the service conditions and the hardness of the individual microstructural constituents are suggested and comments are given on the implications for identifying the circumstances in which Type IV cracking is to be expected. (orig.) 6 refs.

  11. Development and industrial mastering hot rolling procedure for low-ductile steels and alloys

    International Nuclear Information System (INIS)

    Degterenko, V.K.; Sokolov, V.A.

    1980-01-01

    The technique for the development of the sheet hot rolling procedure for low-ductile steels and alloys (0Kh17N14M2, 12Kh21N5T, 20Kh25N20C2,40Kh13, 36NKhTYu etc.) is proposed, using plastometer which permits to obtain the data on the deformation resistance in the wide range of temperatures (800-1300 deg C), of deformation degrees (0.1-0.3) and deformation rates (0.001-300 c -1 ). With the help of the plastometric data processed on the computer the calculation of the rolling regimes for the sheet with improved surface quality is carried out at the more uniform loading on the mill stands

  12. Nickel coating on high strength low alloy steel by pulse current deposition

    Science.gov (United States)

    Nigam, S.; Patel, S. K.; Mahapatra, S. S.; Sharma, N.; Ghosh, K. S.

    2015-02-01

    Nickel is a silvery-white metal mostly used to enhance the value, utility, and lifespan of industrial equipment and components by protecting them from corrosion. Nickel is commonly used in the chemical and food processing industries to prevent iron from contamination. Since the properties of nickel can be controlled and varied over broad ranges, nickel plating finds numerous applications in industries. In the present investigation, pulse current electro-deposition technique has been used to deposit nickel on a high strength low alloy (HSLA) steel substrate.Coating of nickel is confirmed by X-ray diffraction (XRD) and EDAX analysis. Optical microscopy and SEM is used to assess the coating characteristics. Electrochemical polarization study has been carried out to study the corrosion behaviour of nickel coating and the polarisation curves have revealed that current density used during pulse electro-deposition plays a vital role on characteristics of nickel coating.

  13. Low Alloy Steel Structures After Welding with Micro-Jet Cooling

    Directory of Open Access Journals (Sweden)

    Węgrzyn T.

    2017-03-01

    Full Text Available The paper focuses on low alloy steel after innovate welding method with micro-jet cooling. Weld metal deposit (WMD was carried out for welding and for MIG and MAG welding with micro-jet cooling. This method is very promising mainly due to the high amount of AF (acicular ferrite and low amount of MAC (self-tempered martensite, retained austenite, carbide phases in WMD. That structure corresponds with very good mechanical properties, ie. high impact toughness of welds at low temperature. Micro-jet cooling after welding can find serious application in automotive industry very soon. Until that moment only argon, helium and nitrogen were tested as micro-jet gases. In that paper first time various gas mixtures (gas mixtures Ar-CO2 were tested for micro-jet cooling after welding.

  14. Direct Metal Deposition of H13 Tool Steel on Copper Alloy Substrate: Parametric Investigation

    Science.gov (United States)

    Imran, M. Khalid; Masood, S. H.; Brandt, Milan

    2015-12-01

    Over the past decade, researchers have demonstrated interest in tribology and prototyping by the laser aided material deposition process. Laser aided direct metal deposition (DMD) enables the formation of a uniform clad by melting the powder to form desired component from metal powder materials. In this research H13 tool steel has been used to clad on a copper alloy substrate using DMD. The effects of laser parameters on the quality of DMD deposited clad have been investigated and acceptable processing parameters have been determined largely through trial-and-error approaches. The relationships between DMD process parameters and the product characteristics such as porosity, micro-cracks and microhardness have been analysed using scanning electron microscope (SEM), image analysis software (ImageJ) and microhardness tester. It has been found that DMD parameters such as laser power, powder mass flow rate, feed rate and focus size have an important role in clad quality and crack formation.

  15. Regularities in development of surface cracks in low-alloy steel under asymmetric cyclic bending

    International Nuclear Information System (INIS)

    Letunov, V.I.; Shul'ginov, B.S.; Plundrova, I.; Vajnshtok, V.A.; Kramarenko, I.V.

    1985-01-01

    Semielliptical cracks in low-alloy 09g2 and 12gn2mfayu steels are studied for regularities of their growth. It is shown that the growth rate of the semielliptical crack at the preset ΔK and R values is higher in the maximally depressed point of the front than in the point on the surface on the specimen under cyclic bending. A decrease of the 1/C parameter with growth of the semielliptical crack is experimentally established being attributed to the increase in difference of ΔK both in maximally depressed point of the crack front (phi=0) and in the point on the specimen surface (phi= π/2). Experiments have proved the correctness of the previously established formulas of stress-intensity factor calculation for semielliptical surface cracks under bending

  16. Creep of FINEMET alloy at amorphous to nanocrystalline transition

    NARCIS (Netherlands)

    Csach, K.; Miškuf, J.; Juríková, A.; Ocelík, V.

    2009-01-01

    The application of FINEMET-type materials with specific magnetic properties prepared by the crystallization of amorphous alloys is often limited by their brittleness. The structure of these materials consists of nanosized Fe-based grains surrounded with amorphous phase. Then the final macroscopic

  17. Production and characterization of stainless steel based Fe-Cr-Ni-Mn-Si(-Co) shape memory alloys

    International Nuclear Information System (INIS)

    Otubo, J.

    1995-01-01

    It is well known that the Fe based alloys can exhibit shape memory effect due to the γ to ε martensitic transformation. The effect may not be as striking as observed in the NiTi alloy but it might become attractive from the practical point of view. In this work, two compositions of Fe-Cr-Ni-Mn-Si(-Co) stainless steel based shape memory alloy, prepared by the VIM technique, will be presented. The results are good with shape recovery of 95% for a pre-strain of 4% after some training cycles. In terms of workability the alloys produced are worse than the usual AISI304. However, adjusting the thermo-mechanical processing, it is perfectly possible to produce wire as thin as 1,20mm in dia. or down. (orig.)

  18. Pitting corrosion resistance of a novel duplex alloy steel in alkali-activated slag extract in the presence of chloride ions

    Science.gov (United States)

    Shi, Jin-jie; Ming, Jing; Liu, Xin

    2017-10-01

    In this study, two types of reinforcing steels (conventional low-carbon steel and a novel duplex alloy steel with Cr and Mo) were exposed to chloride-contaminated extract solutions (ordinary Portland cement (OPC) extract and alkali-activated slag (AAS) extract) to investigate their pitting corrosion resistance. The results confirm that the pitting corrosion resistance of the alloy steel is much higher than that of the low-carbon steel in both extract solutions with various NaCl concentrations. Moreover, for each type of steel, the AAS extract contributes to a higher pitting corrosion resistance compared with the OPC extract in the presence of chloride ions, likely because of the formation of flocculent precipitates on the steel surface.

  19. Phase transition in a shock loaded 304 stainless steel

    International Nuclear Information System (INIS)

    Naulin, G.

    1989-11-01

    Systematic shock recovery experiments have been performed on a Z2 CN 18-10 stainless steel (304 AISI), shocked in a pressure range of 5-13 GPa. The pulse durations lay between 0.1 μs and 2 μs. The phases transformation γ (fcc) to α' (bcc) is studied. The evolution of microstructures, the nucleation and the coalescence of α' phase embryos have been observed by TEM examinations. Quantitative measurements of the α' phase allow to plot diagrams of transformed phase versus shock pressure and pulse duration. Manganin gages allow to know the pressure evolution during the impact. The Olson and Cohen model describes the development of the α' phase versus the plastic deformation. An adaptation of this model has been developed, which describes the development of the α' phase versus shock pressure and pulse duration. Theoretical laws give a good correlation with experimental results [fr

  20. Evaluation of mechanically alloyed Cu-based powders as filler alloy for brazing tungsten to a reduced activation ferritic-martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Prado, J. de, E-mail: javier.deprado@urjc.es; Sánchez, M.; Ureña, A.

    2017-07-15

    80Cu-20Ti powders were evaluated for their use as filler alloy for high temperature brazing of tungsten to a reduced activation ferritic/martensitic steel (Eurofer), and its application for the first wall of the DEMO fusion reactor. The use of alloyed powders has not been widely considered for brazing purposes and could improve the operational brazeability of the studied system due to its narrower melting range, determined by DTA analysis, which enhances the spreading capabilities of the filler. Ti contained in the filler composition acts as an activator element, reacting and forming several interfacial layers at the Eurofer-braze, which enhances the wettability properties and chemical interaction at the brazing interface. Brazing thermal cycle also activated the diffusion phenomena, which mainly affected to the Eurofer alloying elements causing in it a softening band of approximately 400 μm of thickness. However, this softening effect did not degrade the shear strength of the brazed joints (94 ± 23 MPa), because failure during testing was always located at the tungsten-braze interface. - Highlights: •W-Eurofer brazed joints, manufactured using Cu-based mechanically alloyed powders as filler is proposed. •The benefits derivate from the alloyed composition could improve the operational brazeability of the studied system. •Tested pre-alloyed fillers have a more homogeneous melting stage which enhances its spreading and flowing capabilities. •This behaviour could lead to work with higher heating rates and lower brazing temperatures.