Stablization of Nanotwinned Microstructures in Stainless Steels Through Alloying and Microstructural Design

DTIC Science & Technology

2013-08-23

REPORT Stablization of Nanotwinned Microstructures in Stainless Steels Through Alloying and Microstructural Design 14. ABSTRACT 16. SECURITY...15. SUBJECT TERMS materials design, stainless steels , plastic deformation by twinning, computational materials science, experimental characterization...Standard Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - 30-Jun-2013 Stablization of Nanotwinned Microstructures in Stainless Steels Through

75 FR 11119 - Certain Large Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Japan...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-10

... Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Japan: Extension of Time Limit for... review of the antidumping duty order on certain large diameter carbon and alloy seamless standard, line... manufacturers/exporters: JFE Steel Corporation; Nippon Steel Corporation; NKK Tubes; and Sumitomo Metal...

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

NASA Astrophysics Data System (ADS)

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

Master curve characterization of the fracture toughness behavior in SA508 Gr.4N low alloy steels

NASA Astrophysics Data System (ADS)

Lee, Ki-Hyoung; Kim, Min-Chul; Lee, Bong-Sang; Wee, Dang-Moon

2010-08-01

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 T0 determination for the tempered martensitic SA508 Gr.4N steels.

Fume generation rates for stainless steel, nickel and aluminum alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castner, H.R.

1996-12-01

This paper describes a study of the effects of pulsed welding current on fume produced during gas metal arc welding (GMAW) of stainless steel, nickel, and aluminum alloys. This is an extension of earlier studies of mild steel electrode wire. Reduction of welding fume is important because steady current GMAW of stainless steels and nickel alloys may produce fume that exceeds recommended worker exposure limits for some of the fume constituents. Fume generation from aluminum alloy ER5356 was studied because steady current welding with this alloy produces much higher fume generation rates than ER4043 alloy electrode wire. This work showsmore » that pulsed current can reduce GMAW fume generation rates for Er308L, ER310, and ER312 stainless steel, ERNiCr-3 nickel alloy, and ER5356 aluminum-magnesium alloy electrode wires.« less

Friction Stir Welding of Steel Alloys

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey; Munafo, Paul M. (Technical Monitor)

2001-01-01

The friction stir welding process has been developed primarily for the welding of aluminum alloys. Other higher melting allows such, as steels are much more difficult to join. Special attention must be given to pin tool material selection and welding techniques. This paper addresses the joining of steels and other high melting point materials using the friction stir welding process. Pin tool material and welding parameters will be presented. Mechanical properties of weldments will also be presented. Significance: There are many applications for the friction stir welding process other than low melting aluminum alloys. The FSW process can be expanded for use with high melting alloys in the pressure vessel, railroad and ship building industries.

77 FR 67336 - Certain Small Diameter Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-09

... products subject to the order are small diameter seamless carbon and alloy (other than stainless) steel... Carbon and Alloy Seamless Standard, Line and Pressure Pipe From Romania: Final Results of Antidumping... alloy seamless standard, line and pressure pipe from Romania. The period of review is August 1, 2010...

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Cold resistant nickel-alloy steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Legostaev, Yu.L.; Karchevskaya, N.I.; Karchevnikov, V.P.

1988-05-01

Low-alloy cold-resistant steel 10GNB was developed for the construction of ships and floating drill rigs. The optimal heat-treatment regime for the steel was refinement. Reducing the carbon content improved its weldability and toughness properties. Optical metallography and electron microscopy established that the optimal structure was a tempered martensitic-bainitic mixture with uniformly distributed particles of disperse special niobium carbides NbC. The substructure and the processes of carbide and carbonitride phase segregation were studied by transmission and extraction electron microscopy. In mechanical tests the steel exhibited high resistance to brittle failure. In terms of corrosion resistance the steel corresponds to the requirementsmore » set forth for shipbuilding steels.« less

Method of making high strength, tough alloy steel

DOEpatents

Thomas, Gareth; Rao, Bangaru V. N.

1979-01-01

A high strength, tough alloy steel, particularly suitable for the mining industry, is formed by heating the steel to a temperature in the austenite range (1000.degree.-1100.degree. C.) to form a homogeneous austenite phase and then cooling the steel to form a microstructure of uniformly dispersed dislocated martensite separated by continuous thin boundary films of stabilized retained austenite. The steel includes 0.2-0.35 weight % carbon, at least 1% and preferably 3-4.5% chromium, and at least one other subsitutional alloying element, preferably manganese or nickel. The austenite film is stable to subsequent heat treatment as by tempering (below 300.degree. C.) and reforms to a stable film after austenite grain refinement.

Evaluation and control of environmental corrosion for aluminum and steel alloys

NASA Technical Reports Server (NTRS)

Franklin, D. B.

1977-01-01

Corrosion protection systems for aerospace application and the effects of surface treatments and methods of controlling stress corrosion are evaluated. Chromate pigmented systems were found to be most effective for aluminum alloys; zinc-rich coatings gave the greatest protection to steel alloys. Various steel and aluminum alloys are rated for stress corrosion resistance.

Influence of Short Austenitization Treatments on the Mechanical Properties of Low-Alloy Steels for Hot Forming Applications

NASA Astrophysics Data System (ADS)

Holzweissig, Martin Joachim; Lackmann, Jan; Konrad, Stefan; Schaper, Mirko; Niendorf, Thomas

2015-07-01

The current work elucidates an improvement of the mechanical properties of tool-quenched low-alloy steel by employing extremely short austenitization durations utilizing a press heating arrangement. Specifically, the influence of different austenitization treatments—involving austenitization durations ranging from three to 15 seconds—on the mechanical properties of low-alloy steel in comparison to an industrial standard furnace process was examined. A thorough set of experiments was conducted to investigate the role of different austenitization durations and temperatures on the resulting mechanical properties such as hardness, bending angle, tensile strength, and strain at fracture. The most important finding is that the hardness, the bending angle as well as the tensile strength increase with shortened austenitization durations. Furthermore, the ductility of the steels exhibits almost no difference following the short austenitization durations and the standard furnace process. The enhancement of the mechanical properties imposed by the short heat treatments investigated, is related to a refinement of microstructural features as compared to the standard furnace process.

77 FR 21734 - Certain Small Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Romania...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-11

... Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Romania: Extension of Time Limit for... diameter carbon and alloy seamless standard, line and pressure pipe from Romania for the period August 1... investigation based upon the allegation of the petitioner, U.S. Steel. See the memorandum to Susan Kuhbach dated...

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

Code of Federal Regulations, 2012 CFR

2012-10-01

... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and armor...

48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and armor...

48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

Code of Federal Regulations, 2014 CFR

2014-10-01

... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and armor...

48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

Code of Federal Regulations, 2013 CFR

2013-10-01

... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and armor...

48 CFR 252.225-7030 - Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of Carbon, Alloy, and Armor Steel Plate. 252.225-7030 Section 252.225-7030 Federal Acquisition... Acquisition of Carbon, Alloy, and Armor Steel Plate. As prescribed in 225.7011-3, use the following clause: Restriction on Acquisition of Carbon, Alloy, and Armor Steel Plate (DEC 2006) (a) Carbon, alloy, and armor...

Microstructural design in low alloy steels

NASA Technical Reports Server (NTRS)

Honeycombe, R. W. K.

1982-01-01

The evolution of microalloyed steels from plain carbon steels is examined with emphasis on grain size control by use of Nb, Ti and V additions and by the application of controlled rolling. The structural changes during controlled rolling are described as well as the influence of alloying elements on these changes, and on the final microstructure. The achievement of high strength and toughness is discussed including the role of inclusions.

Low-carbon martensitic steels. Alloying and properties

NASA Astrophysics Data System (ADS)

Kleiner, L. M.; Shatsov, A. A.; Larinin, D. M.

2011-03-01

Requirements on the structure of a steel with structural strength and a set of characteristics higher than those of medium-carbon steels with a structure of tempered sorbite are formulated. Principles for choosing compositions for process-adaptable low-carbon martensitic steels are presented. The combination of carbon and alloying elements providing high stability of austenite in the ranges of normal and intermediate transformations is determined, which makes it possible to obtain lath martensite in slow cooling.

75 FR 20342 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-19

...-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty Administrative Review and Rescission of...- alloy steel pipe from Mexico. See Certain Circular Welded Non-Alloy Steel Pipe From Mexico; Preliminary... remaining three respondents. See Certain Circular Welded Non-Alloy Steel Pipe from Mexico: Notice of Partial...

78 FR 60316 - Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-01

... (Second Review)] Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad... certain alloy steel wire rod from Brazil and antidumping duty orders on carbon and certain alloy steel... reviews of the antidumping duty order on carbon and certain alloy steel wire rod from Mexico. The...

Effect of Stress Relief Annealing on Microstructure & Mechanical Properties of Welded Joints Between Low Alloy Carbon Steel and Stainless Steel

NASA Astrophysics Data System (ADS)

Nivas, R.; Das, G.; Das, S. K.; Mahato, B.; Kumar, S.; Sivaprasad, K.; Singh, P. K.; Ghosh, M.

2017-01-01

Two types of welded joints were prepared using low alloy carbon steel and austenitic stainless steel as base materials. In one variety, buttering material and weld metal were Inconel 82. In another type, buttering material and weld metal were Inconel 182. In case of Inconel 82, method of welding was GTAW. For Inconel 182, welding was done by SMAW technique. For one set of each joints after buttering, stress relief annealing was done at 923 K (650 °C) for 90 minutes before further joining with weld metal. Microstructural investigation and sub-size in situ tensile testing in scanning electron microscope were carried out for buttered-welded and buttered-stress relieved-welded specimens. Adjacent to fusion boundary, heat-affected zone of low alloy steel consisted of ferrite-pearlite phase combination. Immediately after fusion boundary in low alloy steel side, there was increase in matrix grain size. Same trend was observed in the region of austenitic stainless steel that was close to fusion boundary between weld metal-stainless steel. Close to interface between low alloy steel-buttering material, the region contained martensite, Type-I boundary and Type-II boundary. Peak hardness was obtained close to fusion boundary between low alloy steel and buttering material. In this respect, a minimum hardness was observed within buttering material. The peak hardness was shifted toward buttering material after stress relief annealing. During tensile testing no deformation occurred within low alloy steel and failure was completely through buttering material. Crack initiated near fusion boundary between low alloy steel-buttering material for welded specimens and the same shifted away from fusion boundary for stress relieved annealed specimens. This observation was at par with the characteristics of microhardness profile. In as welded condition, joints fabricated with Inconel 82 exhibited superior bond strength than the weld produced with Inconel 182. Stress relief annealing

Simulation of Structural Transformations in Heating of Alloy Steel

NASA Astrophysics Data System (ADS)

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.

48 CFR 225.7011 - Restriction on carbon, alloy, and armor steel plate.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Restriction on carbon, alloy, and armor steel plate. 225.7011 Section 225.7011 Federal Acquisition Regulations System DEFENSE... on carbon, alloy, and armor steel plate. ...

48 CFR 225.7011 - Restriction on carbon, alloy, and armor steel plate.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Restriction on carbon, alloy, and armor steel plate. 225.7011 Section 225.7011 Federal Acquisition Regulations System DEFENSE... on carbon, alloy, and armor steel plate. ...

48 CFR 225.7011 - Restriction on carbon, alloy, and armor steel plate.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Restriction on carbon, alloy, and armor steel plate. 225.7011 Section 225.7011 Federal Acquisition Regulations System DEFENSE... on carbon, alloy, and armor steel plate. ...

48 CFR 225.7011 - Restriction on carbon, alloy, and armor steel plate.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Restriction on carbon, alloy, and armor steel plate. 225.7011 Section 225.7011 Federal Acquisition Regulations System DEFENSE... on carbon, alloy, and armor steel plate. ...

48 CFR 225.7011 - Restriction on carbon, alloy, and armor steel plate.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Restriction on carbon, alloy, and armor steel plate. 225.7011 Section 225.7011 Federal Acquisition Regulations System DEFENSE... on carbon, alloy, and armor steel plate. ...

Self-Pierce Riveting of Three Aluminium Alloy and Mild Steel Sheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mori, K.; Abe, Y.; Sakai, S.

2010-06-15

Three aluminium alloy and steel sheets were joined with a self-piercing rivet. Self-pierce riveting has the function of joining steel and aluminium alloys having very different melting points due to plastic joining. The requisites for joining the three sheets are the driving of the rivet leg through the middle sheet, the flaring of the rivet leg in the lower sheet and the prevention of the fracture of the lower sheet. The joinability for various combinations of the three sheets was determined. When the rivet leg is small, no driving through the middle sheet occurs, the lower sheet ruptures for amore » large rivet leg. In addition, 980 MPa high strength steel, mild steel and aluminium alloy sheets were joined by the self-pierce riveting.« less

Materials data handbook: Stainless steel alloy A-286

NASA Technical Reports Server (NTRS)

Muraca, R. F.; Whittick, J. S.

1972-01-01

A summary of the materials property information for stainless steel alloy A-286 is presented. The scope of the information includes physical and mechanical properties at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and bonding is developed.

Process for making a martensitic steel alloy fuel cladding product

DOEpatents

Johnson, Gerald D.; Lobsinger, Ralph J.; Hamilton, Margaret L.; Gelles, David S.

1990-01-01

This is a very narrowly defined martensitic steel alloy fuel cladding material for liquid metal cooled reactors, and a process for making such a martensitic steel alloy material. The alloy contains about 10.6 wt. % chromium, about 1.5 wt. % molybdenum, about 0.85 wt. % manganese, about 0.2 wt. % niobium, about 0.37 wt. % silicon, about 0.2 wt. % carbon, about 0.2 wt. % vanadium, 0.05 maximum wt. % nickel, about 0.015 wt. % nitrogen, about 0.015 wt. % sulfur, about 0.05 wt. % copper, about 0.007 wt. % boron, about 0.007 wt. % phosphorous, and with the remainder being essentially iron. The process utilizes preparing such an alloy and homogenizing said alloy at about 1000.degree. C. for 16 hours; annealing said homogenized alloy at 1150.degree. C. for 15 minutes; and tempering said annealed alloy at 700.degree. C. for 2 hours. The material exhibits good high temperature strength (especially long stress rupture life) at elevated temperature (500.degree.-760.degree. C.).

Microstructural development during solidification of stainless steel alloys

NASA Astrophysics Data System (ADS)

Elmer, J. W.; Allen, S. M.; Eagar, T. W.

1989-10-01

The microstructures that develop during the solidification of stainless steel alloys are related to the solidification conditions and the specific alloy composition. The solidification conditions are determined by the processing method, i.e., casting, welding, or rapid solidification, and by parametric variations within each of these techniques. One variable that has been used to characterize the effects of different processing conditions is the cooling rate. This factor and the chemical composition of the alloy both influence (1) the primary mode of solidification, (2) solute redistribution and second-phase formation during solidification, and (3) the nucleation and growth behavior of the ferrite-to-austenite phase transformation during cooling. Consequently, the residual ferrite content and the microstructural morphology depend on the cooling rate and are governed by the solidification process. This paper investigates the influence of cooling rate on the microstructure of stainless steel alloys and describes the conditions that lead to the many microstructural morphologies that develop during solidification. Experiments were performed on a series of seven high-purity Fe-Ni-Cr alloys that spanned the line of twofold saturation along the 59 wt pct Fe isopleth of the ternary alloy system. High-speed electron-beam surface-glazing was used to melt and resolidify these alloys at scan speeds up to 5 m/s. The resulting cooling rates were shown to vary from 7°C/s to 7.5×106°C/s, and the resolidified melts were analyzed by optical metallographic methods. Five primary modes of solidification and 12 microstructural morphologies were characterized in the resolidified alloys, and these features appear to be a complete “set” of the possible microstructures for 300-series stainless steel alloys. The results of this study were used to create electron-beam scan speed vs composition diagrams, which can be used to predict the primary mode of solidification and the

Copper modified austenitic stainless steel alloys with improved high temperature creep resistance

DOEpatents

Swindeman, R.W.; Maziasz, P.J.

1987-04-28

An improved austenitic stainless steel that incorporates copper into a base Fe-Ni-Cr alloy having minor alloying substituents of Mo, Mn, Si, T, Nb, V, C, N, P, B which exhibits significant improvement in high temperature creep resistance over previous steels. 3 figs.

Creep modeling for life evaluation and strengthening mechanism of tungsten alloyed 9-12% Cr steels

NASA Astrophysics Data System (ADS)

Park, Kyu-Seop; Bae, Dong-Sik; Lee, Sung-Keun; Lee, Goo-Hyun; Kim, Jung-Ho; Endo, Takao

2006-10-01

Recently, high strength tungsten (W) alloyed steels have been developed for use in power plants with higher steam conditions for environmental reasons as well as the improvement of thermal efficiency resulting in lower fuel costs. In order to establish a creep modeling of high strength martensitic steel and to understand the basic role of W in tungsten alloyed 9-12Cr steels, conventional martensitic steels (X20CrMoV121, X20CrMoWV121, and Mod9Cr-1Mo) and tungsten alloyed steels (NF616 and HCM12A) were employed for creep tests and creep behavior analyses by the Ω method. The proposed creep model, which takes into account both primary and tertiary creep, satisfactorily described the creep curves and accurately predicted creep life, as martensitic steel undergoes a relatively large amount of primary creep, up to nearly 30%, over its normal life. The tungsten alloyed steels exhibited a smaller minimum creep rate and a larger stress exponent compared to the conventional steels. In addition, in tungsten alloyed steel, the Ω value features strong stress dependence such that creep life is prolonged at lower stresses due to high Ω values. The importance of the Ω value from the standpoint of creep strengthening in primary and tertiary creep is discussed.

Alloy steel nuts for bolting for high-pressure and high-temperature service (ASME SA-194 with additional requirements)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This standard covers alloy steel nuts for bolting for high-pressure and high-temperature service in nuclear and associated applications. This standard does not cover bar or other starting materials. The only implied special considerations for starting materials are that they be capable of passing the required tests when processed into finished products in accordance with this standard.

Reaction of Unalloyed and Cr-Mo Alloyed Steels with Nitrogen from the Sintering Atmosphere

NASA Astrophysics Data System (ADS)

Dlapka, Magdalena; Gierl-Mayer, Christian; Calderon, Raquel de Oro; Danninger, Herbert; Bengtsson, Sven; Dudrova, Eva

2016-12-01

Nitrogen is usually regarded as an inert sintering atmosphere for PM steels; however, this cannot be taken for granted in particular for steels alloyed with nitride forming elements. Among those elements, chromium has become more and more important as an alloying element in sintered low alloy structural steels in the last decade due to the moderate alloying cost and the excellent mechanical properties obtainable, in particular when sinter hardening is applied. The high affinity of Cr to oxygen and the possible ways to overcome related problems have been the subject of numerous studies, while the fact that chromium is also a fairly strong nitride forming element has largely been neglected at least for low alloy steel grades, although frequently used materials like steels from Cr and Cr-Mo prealloyed powders are commonly sintered in atmospheres consisting mainly of nitrogen. In the present study, nitrogen pickup during sintering at different temperatures and for varying times has been studied for Cr-Mo prealloyed steel grades as well as for unalloyed carbon steel. Also the effect of the cooling rate and its influence on the properties, of the microstructure and the composition have been investigated. It showed that the main nitrogen uptake occurs not during isothermal sintering but rather during cooling. It could be demonstrated that a critical temperature range exists within which the investigated CrM-based steel is particularly sensitive to nitrogen pickup.

Optimal Recycling of Steel Scrap and Alloying Elements: Input-Output based Linear Programming Method with Its Application to End-of-Life Vehicles in Japan.

PubMed

Ohno, Hajime; Matsubae, Kazuyo; Nakajima, Kenichi; Kondo, Yasushi; Nakamura, Shinichiro; Fukushima, Yasuhiro; Nagasaka, Tetsuya

2017-11-21

Importance of end-of-life vehicles (ELVs) as an urban mine is expected to grow, as more people in developing countries are experiencing increased standards of living, while the automobiles are increasingly made using high-quality materials to meet stricter environmental and safety requirements. While most materials in ELVs, particularly steel, have been recycled at high rates, quality issues have not been adequately addressed due to the complex use of automobile materials, leading to considerable losses of valuable alloying elements. This study highlights the maximal potential of quality-oriented recycling of ELV steel, by exploring the utilization methods of scrap, sorted by parts, to produce electric-arc-furnace-based crude alloy steel with minimal losses of alloying elements. Using linear programming on the case of Japanese economy in 2005, we found that adoption of parts-based scrap sorting could result in the recovery of around 94-98% of the alloying elements occurring in parts scrap (manganese, chromium, nickel, and molybdenum), which may replace 10% of the virgin sources in electric arc furnace-based crude alloy steel production.

78 FR 76653 - Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-18

... 962 (Second Review)] Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova... orders on carbon and certain alloy steel wire rod from Brazil, Indonesia, Mexico, Moldova, Trinidad and... carbon and certain alloy steel wire rod from Brazil, Indonesia, Mexico, Moldova, Trinidad and Tobago, and...

Alternative to Nitric Acid for Passivation of Stainless Steel Alloys

NASA Technical Reports Server (NTRS)

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.

Carburizing treatment of low alloy steels: Effect of technological parameters

NASA Astrophysics Data System (ADS)

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.

Amorphous Alloy Surpasses Steel and Titanium

NASA Technical Reports Server (NTRS)

2004-01-01

In the same way that the inventions of steel in the 1800s and plastic in the 1900s sparked revolutions for industry, a new class of amorphous alloys is poised to redefine materials science as we know it in the 21st century. Welcome to the 3rd Revolution, otherwise known as the era of Liquidmetal(R) alloys, where metals behave similar to plastics but possess more than twice the strength of high performance titanium. Liquidmetal alloys were conceived in 1992, as a result of a project funded by the California Institute of Technology (CalTech), NASA, and the U.S. Department of Energy, to study the fundamentals of metallic alloys in an undercooled liquid state, for the development of new aerospace materials. Furthermore, NASA's Marshall Space Flight Center contributed to the development of the alloys by subjecting the materials to testing in its Electrostatic Levitator, a special instrument that is capable of suspending an object in midair so that researchers can heat and cool it in a containerless environment free from contaminants that could otherwise spoil the experiment.

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Effect of Alloying Elements on Tensile Properties, Microstructure, and Corrosion Resistance of Reinforcing Bar Steel

NASA Astrophysics Data System (ADS)

Panigrahi, B. K.; Srikanth, S.; Sahoo, G.

2009-11-01

The effect of copper, phosphorus, and chromium present in a semikilled reinforcing bar steel produced by in-line quenching [thermomechanical treatment (TMT)] process on the tensile properties, microstructure, and corrosion resistance of steel in simulated chloride environment has been investigated. The results have been compared with that of a semikilled C-Mn reinforcing bar steel without these alloying elements produced by the same process route. Though the amount of phosphorus (0.11 wt.%) was higher than that specified by ASTM A 706 standard, the Cu-P-Cr steel exhibited a composite microstructure, and good balance of yield stress, tensile stress, elongation, and ultimate tensile to yield stress ratio. Two conventional test methods, namely, the salt fog, and potentiodynamic polarization tests, were used for the corrosion test. The rust formed on Cu-P-Cr steel was adherent, and was of multiple colors, while the corrosion products formed on the C-Mn steel were weakly adherent and relatively darker blue. Also, the free corrosion potential of the Cu-P-Cr steel was nobler, and the corrosion current was markedly lower than that of a C-Mn rebar. The Cu-P-Cr steel did not develop any pits/deep grooves on its surface even after the prolonged exposure to salt fog. The improved corrosion resistance of the Cu-P-Cr steel has been attributed to the presence of copper, phosphorus, and small amount of chromium in the dense, adherent rust layer on the surface of reinforcing steel bar. A schematic mechanism of charge transfer has been proposed to explain the improved corrosion resistance of the Cu-P-Cr alloyed TMT rebar.

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

NASA Astrophysics Data System (ADS)

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.

Cavitation Erosion of Electro Spark Deposited Nitinol vs. Stellite Alloy on Stainless Steel Substrate

DTIC Science & Technology

2015-07-15

EROSION OF ELECTRO SPARK DEPOSITED NITINOL VS. STELLITE® ALLOY ON STAINLESS STEEL SUBSTRATE Theresa A. Hoffard Lean-Miguel San Pedro Mikhail...SUBTITLE 5a. CONTRACT NUMBER CAVITATION EROSION TESTING OF ELECTRO SPARK DEPOSITED NITINOL VS STELLITE® ALLOY ON STAINLESS STEEL SUBTRATE 5b. GRANT...of combining Nitinol (NiTi) superelastic metal alloy with ElectroSpark Deposition (ESD) technology to increase the cavitation erosion resistance of

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez, J.; University of Campinas; Ramirez, A.J., E-mail: ramirezlondono.1@osu.edu

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 showedmore » 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.« less

Steam Oxidation Behavior of Advanced Steels and Ni-Based Alloys at 800 °C

NASA Astrophysics Data System (ADS)

Dudziak, T.; Boroń, L.; Deodeshmukh, V.; Sobczak, J.; Sobczak, N.; Witkowska, M.; Ratuszek, W.; Chruściel, K.

2017-03-01

This publication studies the steam oxidation behavior of advanced steels (309S, 310S and HR3C) and Ni-based alloys (Haynes® 230®, alloy 263, alloy 617 and Haynes® 282®) exposed at 800 °C for 2000 h under 1 bar pressure, in a pure water steam system. The results revealed that all exposed materials showed relatively low weight gain, with no spallation of the oxide scale within the 2000 h of exposure. XRD analysis showed that Ni-based alloys developed an oxide scale consisting of four main phases: Cr2O3 (alloy 617, Haynes® 282®, alloy 263 and Haynes® 230®), MnCr2O4 (alloy 617, Haynes® 282® and Haynes® 230®), NiCr2O4 (alloy 617) and TiO2 (alloy 263, Haynes® 282®). In contrast, advanced steels showed the development of Cr2O3, MnCr2O4, Mn7SiO12, FeMn(SiO4) and SiO2 phases. The steel with the highest Cr content showed the formation of Fe3O4 and the thickest oxide scale.

Pressurized metallurgy for high performance special steels and alloys

NASA Astrophysics Data System (ADS)

Jiang, Z. H.; Zhu, H. C.; Li, H. B.; Li, Y.; Liu, F. B.

2016-07-01

The pressure is one of the basic parameters which greatly influences the metallurgical reaction process and solidification of steels and alloys. In this paper the history and present situation of research and application of pressurized metallurgy, especially pressurized metallurgy for special steels and alloys have been briefly reviewed. In the following part the physical chemistry of pressurized metallurgy is summarized. It is shown that pressurizing may change the conditions of chemical reaction in thermodynamics and kinetics due to the pressure effect on gas volume, solubility of gas and volatile element in metal melt, activity or activity coefficient of components, and change the physical and chemical properties of metal melt, heat transfer coefficient between mould and ingot, thus greatly influencing phase transformation during the solidification process and the solidification structure, such as increasing the solidification nucleation rate, reducing the critical nucleation radius, accelerating the solidification speed and significant macro/micro-structure refinement, and eliminating shrinkage, porosity and segregation and other casting defects. In the third part the research works of pressured metallurgy performed by the Northeastern University including establishment of pressurized induction melting (PIM) and pressurized electroslag remelting (PESR) equipments and development of high nitrogen steels under pressure are described in detail. Finally, it is considered in the paper that application of pressurized metallurgy in manufacture of high performance special steels and alloys is a relatively new research area, and its application prospects will be very broad and bright.

Effect of Sn Micro-alloying on Recrystallization Nucleation and Growth Processes of Ferritic Stainless Steels

NASA Astrophysics Data System (ADS)

He, Tong; Bai, Yang; Liu, Xiuting; Guo, Dan; Liu, Yandong

2018-04-01

We investigated the effect of Sn micro-alloying on recrystallization nucleation and growth processes of ferritic stainless steels. The as-received hot rolled sheets were cold rolled up to 80% reduction and then annealed at 740-880 °C for 5 min. The cold rolling and recrystallization microstructures and micro-textures of Sn-containing and Sn-free ferritic stainless steels were all determined by electron backscatter diffraction. Our Results show that Sn micro-alloying has important effects on recrystallization nucleation and growth processes of ferritic stainless steels. Sn micro-alloying conduces to grain fragmentation in the deformation band, more fragmented grains are existed in Sn-containing cold rolled sheets, which provides more sites for recrystallization nucleation. Sn micro-alloying also promotes recrystallization process and inhibits the growth of recrystallized grains. The recrystallization nucleation and growth mechanism of Sn-containing and Sn-free ferritic stainless steels are both characterized by orientation nucleation and selective growth, but Sn micro-alloying promotes the formation of γ-oriented grains. Furthermore, Sn micro-alloying contributes to the formation of Σ13b CSL boundaries and homogeneous γ-fiber texture. Combining the results of microstructure and micro-texture, the formability of Sn-containing ferritic stainless steels will be improved to some extent.

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

46 CFR 54.25-15 - Low temperature operation-high alloy steels (modifies UHA-23(b) and UHA-51).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Low temperature operation-high alloy steels (modifies... (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-15 Low temperature operation—high alloy steels (modifies UHA-23(b) and UHA-51). (a) Toughness...

Stress Corrosion Cracking and Hydrogen Embrittlement of Thick Section High Strength Low Alloy Steel

DTIC Science & Technology

1986-06-01

copper and especially molybdenum. Dual phase HSLA steels are comprised of islands of martensite or bainite in a ferrite matrix. The... Copper Steels", TransactionN AIME, Volume 105, pp. 133-166, 1933. 60. Creswick, W. E., "Commercial Development of a Rimmed Low Alloy Precipitation ... precipitates all serve to minimize the aggregate effects of hydrogen. 82 - ------- ------ - 3. MATERIAL 3.1 bSLA STEELS High strength low alloy

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

75 FR 21658 - Carbon and Certain Alloy Steel Wire Rod From Trinidad and Tobago

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-26

... Certain Alloy Steel Wire Rod From Trinidad and Tobago AGENCY: United States International Trade Commission... Investigation No. 731-TA-961 concerning carbon and certain alloy steel wire rod (``wire rod'') from Trinidad and... of imports of wire rod from Trinidad and Tobago that were sold in the United States at less than fair...

78 FR 41366 - Certain Large Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe (Over 4 1/2

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-10

... Carbon and Alloy Seamless Standard, Line, and Pressure Pipe (Over 4 \\1/2\\ Inches) From Japan: Preliminary... seamless standard, line, and pressure pipe (over 4 \\1/2\\ inches) (large diameter seamless pipe) from Japan.../exporters of subject merchandise, Canadian Natural Resources Limited (CNRL), JFE Steel Corporation (JFE...

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

NASA Astrophysics Data System (ADS)

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

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

NASA Astrophysics Data System (ADS)

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.

Effect of process parameters on formability of laser melting deposited 12CrNi2 alloy steel

NASA Astrophysics Data System (ADS)

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.

Influence of alloying elements in rust formed on low alloyed steels. A study by x-ray diffraction and Mössbauer spectroscopy

NASA Astrophysics Data System (ADS)

Haces, C.; Furet, N. R.; Muleshkova, L.

1991-11-01

In this research, three Bulgarian steels were employed, one carbon (08KP) and other two low alloyed (KBC) and (KORAT). These three steels were exposed on a test site affected with industrial pollution in the Cuban climate, for a period of one, two and three years. The phase composition obtained by means of XRD and Mössbauer spectroscopy is mainly a mixture of Goethite (α-FeOOH) and Lepidocrocite (γ-FEOOH) in the three steels. The mean width of the Goethite reflexions, as determined in the diffractograms, is increased in the case of the low alloyed steels, while in Mössbauer spectra two types of magnetic arrangement for Goethite appear, one antiferromagnetic (sextet) and the other superparamagnetic (doublet). This behaviour is due to the effect of the small particle size and the presence of alloying elements in the structure. In this paper, the values of the areas of both effects are discussed from the greater formation of superparamagnetic Goethite in the KORAT steel which exibits the lowest corrosion rate.

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

NASA Astrophysics Data System (ADS)

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.

New alloys to conserve critical elements. [replacing chromium in steels

NASA Technical Reports Server (NTRS)

Stephens, J. R.

1978-01-01

Previous studies and surveys on availability of domestic reserves have shown that chromium is a most critical element within the U.S. metal industry. More precisely, the bulk of chromium is consumed in the production of stainless steels, specifically Type 304 stainless steel (304SS) which contains 18% Cr. The present paper deals with means of reducing chromium in commercial stainless steels by substituting more abundant or less expensive elements with the intent of maintaining the properties of 304SS. The discussion focuses on some of the oxidation and corrosion properties of new substitute stainless steels with only 12% Cr, which represents a potential saving of 33% of the chromium consumed in the production of 304SS. The alloying elements substituted for Cr in 304SS are selected according to their potential for protective oxide formation during high-temperature oxidation; these are Al, Si, Ti, Y, and misch metal which is 99.7% rare-earth metals containing 50 to 55% cerium. Other alloying elements to impart corrosion resistance are Mn, Mo, and V.

76 FR 31940 - Circular Welded Non-Alloy Steel Pipe From Taiwan: Notice of Rescission of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-02

... Steel Pipe From Taiwan: Notice of Rescission of Antidumping Duty Administrative Review AGENCY: Import... review of the antidumping duty order on circular welded non-alloy steel pipe from Taiwan. The period of... review of the antidumping duty order on circular welded non-alloy steel pipe from Taiwan. See Antidumping...

Replacement of steel parts with extruded aluminum alloys in an automobile

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Cryo-quenched Fe-Ni-Cr alloy single crystals: A new decorative steel

DOE PAGES

Boatner, Lynn A.; Kolopus, James A.; Lavrik, Nicolay V.; ...

2016-08-31

In this paper, a decorative steel is described that is formed by a process that is unlike that of the fabrication methods utilized in making the original Damascus steels over 2000 years ago. The decorative aspect of the steel arises from a three-dimensional surface pattern that results from cryogenically quenching polished austenitic alloy single crystals into the martensitic phase that is present below 190 K. No forging operations are involved – the mechanism is entirely based on the metallurgical phase properties of the ternary alloy. The symmetry of the decorative pattern is determined and controlled by the crystallographic orientation andmore » symmetry of the 70%Fe,15%Ni,15%Cr alloy single crystals. Finally, in addition to using “cuts” made along principal crystallographic surface directions, an effectively infinite number of other random-orientation “cuts” can be utilized to produce decorative patterns where each pattern is unique after the austenitic-to-martensitic phase transformation.« less

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

NASA Astrophysics Data System (ADS)

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.

Radiation resistant austenitic stainless steel alloys

DOEpatents

Maziasz, Philip J.; Braski, David N.; Rowcliffe, Arthur F.

1989-01-01

An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01% to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties.

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

NASA Astrophysics Data System (ADS)

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.

Improvement of corrosion resistance of low-alloy steels by resurfacing using multifunction cavitation in water

NASA Astrophysics Data System (ADS)

Ijiri, Masataka; Yoshimura, Toshihiko

2018-02-01

Low-alloy steels are based on carbon steel in combination with several percent or less (in many cases, 1 mass%) alloying elements, and they offer improved resistance to corrosion at a cost slightly higher than that of carbon steel. However, these materials do not exhibit the same corrosion resistance as stainless steel. The authors have previously developed a novel multifunction cavitation (MFC) technique, which combines ultrasonic cavitation with water jet cavitation. In this study, MFC was used to modify the surface of Cr-Mo steel (SCM435) and Ni-Cr-Mo steel (SNCM630). MFC was found to improve the residual stress value of the material as the result of surface modification while also imparting high strength and superior corrosion resistance.

Mechanical alloying of lanthana-bearing nanostructured ferritic steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Somayeh Paseban; Indrajit Charit; Yaqiao Q. Wu

2013-09-01

A novel nanostructured ferritic steel powder with the nominal composition Fe–14Cr–1Ti–0.3Mo–0.5La2O3 (wt.%) was developed via high energy ball milling. La2O3 was added to this alloy instead of the traditionally used Y2O3. The effects of varying the ball milling parameters, such as milling time, steel ball size and ball to powder ratio, on the mechanical properties and micro structural characteristics of the as-milled powder were investigated. Nanocrystallites of a body-centered cubic ferritic solid solution matrix with a mean size of approximately 20 nm were observed by transmission electron microscopy. Nanoscale characterization of the as-milled powder by local electrode atom probe tomographymore » revealed the formation of Cr–Ti–La–O-enriched nanoclusters during mechanical alloying. The Cr:Ti:La:O ratio is considered “non-stoichiometric”. The average size (radius) of the nanoclusters was about 1 nm, with number density of 3.7 1024 m3. The mechanism for formation of nanoclusters in the as-milled powder is discussed. La2O3 appears to be a promising alternative rare earth oxide for future nanostructured ferritic steels.« less

Development of Low Alloy Ti-B Steels for High Temperature Service Applications

DTIC Science & Technology

1952-04-01

Ti-B steels . Ordinarily, martensite or a hardened acicular ferrite structure in steel is associated with extremely low creep strength. However, the...12000 F. The ability of the Ti-B sheet steels to suppress the ferrite transformation to the martensite or lower bainite temperature range upon air...APPROVED FOR PUBLIC mEESX_ DISTRIBUTION UNjfljarT, • WJADC TECHNICAL REPORT 52-77 DEVELOPMENT OF LOW ALLOY Ti-B STEELS FOR HIGH TEMPERATURE SERVICE

Impacts of Modification of Alloying Method on Inclusion Evolution in RH Refining of Silicon Steel.

PubMed

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.

Radiation resistant austenitic stainless steel alloys

DOEpatents

Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.

1987-02-11

An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01 to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties. 4 figs.

Microstructure and Mechanical Properties of Friction Stir Welded Aluminum Alloy/Stainless Steel Lap Joints

NASA Astrophysics Data System (ADS)

Ogura, Tomo; Nishida, Taichi; Nishida, Hidehito; Yoshikawa, Syuhei; Yoshida, Takumi; Omichi, Noriko; Fujimoto, Mitsuo; Hirose, Akio

The mechanical properties and interfacial microstructure of an aluminum alloy/stainless steel dissimilar lap joint using friction stir welding (FSW) were characterized. In an FSWed A3003 aluminum alloy-SUS304 steel lap joint, the strength on the advancing side was larger than that at the retreating side. TEM observation indicated that a sound joint can be obtained from the stage of the formation of the amorphous layer owing to the mechanical alloying effects before the formation of intermetallic compounds. This lap joining technique was also successfully applied to A6061-T6 aluminum alloy-grooved SUS304 plates. The maximum tensile strength of the lap joint was approximately the same as that of the base alloy, however, the proof stress of the joint decreased with the dissolution of the β″ phase in the A6061 aluminium alloy, which is caused by the generation of heat during friction stir welding.

The development of ultrahigh strength low alloy cast steels with increased toughness

NASA Astrophysics Data System (ADS)

Lynch, Paul C.

This work describes the initial work on the development of the next generation of ultrahigh strength low alloy (UHSLA) cast steels. These UHSLA cast steels have both ultrahigh strength levels and good impact toughness. The influence of heat treatment, secondary processing using hot isostatic processing (HIP), and chemical composition on the microstructure and properties of UHSLA cast steels have been evaluated. The extent of microsegregation reduction expected during the heat treatment of UHSLA cast steels has also been estimated by diffusion modeling. This new family of UHSLA cast steels is similar in composition and properties to UHSLA wrought steels. However, the heat treatment and secondary processing of the UHSLA cast steels is used to develop microstructures and properties typically developed through thermomechanical processing and heat treatment for wrought UHSLA steels. Two martensitic UHSLA steels, 4340+ (silicon modified 4340) and ES-1 were investigated for this study. For the 4340+ alloy, heat treatment variables evaluated include homogenization temperature and time, tempering temperature, and austempering temperature and time. For the ES-1 alloy, heat treatment variables evaluated include homogenization temperature and time, austenization temperature, cryogenic treatment, and tempering temperature. The effect of high temperature hot isostatic processing (HIP) on the 4340+ and ES- 1 alloys was also investigated. Tensile properties, charpy v-notch impact toughness (CVN), microstructures, and fractographs have all been characterized after heat treatment. The effects of HIP on microporosity reduction in the ES-1 alloy were also investigated. The experiments carried out on the investment cast 4340+ alloy have shown that increasing the homogenization temperature can increase CVN without changing the ultimate tensile strength (UTS) or yield strength (YS) of the cast material. By replacing the homogenization step in the conventional heat treatment process with

49 CFR 178.504 - Standards for steel drums.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for steel drums. 178.504 Section 178.504...-bulk Performance-Oriented Packaging Standards § 178.504 Standards for steel drums. (a) The following are identification codes for steel drums: (1) 1A1 for a non-removable head steel drum; and (2) 1A2 for...

49 CFR 178.504 - Standards for steel drums.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for steel drums. 178.504 Section 178.504...-Oriented Packaging Standards § 178.504 Standards for steel drums. (a) The following are identification codes for steel drums: (1) 1A1 for a non-removable head steel drum; and (2) 1A2 for a removable head...

49 CFR 178.504 - Standards for steel drums.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for steel drums. 178.504 Section 178.504...-Oriented Packaging Standards § 178.504 Standards for steel drums. (a) The following are identification codes for steel drums: (1) 1A1 for a non-removable head steel drum; and (2) 1A2 for a removable head...

49 CFR 178.504 - Standards for steel drums.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for steel drums. 178.504 Section 178.504...-Oriented Packaging Standards § 178.504 Standards for steel drums. (a) The following are identification codes for steel drums: (1) 1A1 for a non-removable head steel drum; and (2) 1A2 for a removable head...

49 CFR 178.504 - Standards for steel drums.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Standards for steel drums. 178.504 Section 178.504...-Oriented Packaging Standards § 178.504 Standards for steel drums. (a) The following are identification codes for steel drums: (1) 1A1 for a non-removable head steel drum; and (2) 1A2 for a removable head...

Nitride alloy layer formation of duplex stainless steel using nitriding process

NASA Astrophysics Data System (ADS)

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.

Factors affecting the strength of multipass low-alloy steel weld metal

NASA Technical Reports Server (NTRS)

Krantz, B. M.

1972-01-01

The mechanical properties of multipass high-strength steel weld metals depend upon several factors, among the most important being: (1) The interaction between the alloy composition and weld metal cooling rate which determines the as-deposited microstructure; and (2) the thermal effects of subsequent passes on each underlying pass which alter the original microstructure. The bulk properties of a multipass weld are therefore governed by both the initial microstructure of each weld pass and its subsequent thermal history. Data obtained for a high strength low alloy steel weld metal confirmed that a simple correlation exists between mechanical properties and welding conditions if the latter are in turn correlated as weld cooling rate.

An Industrial Perspective on Environmentally Assisted Cracking of Some Commercially Used Carbon Steels and Corrosion-Resistant Alloys

NASA Astrophysics Data System (ADS)

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.

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

NASA Technical Reports Server (NTRS)

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.

Transformation process for production of ultrahigh carbon steels and new alloys

DOEpatents

Strum, M.J.; Goldberg, A.; Sherby, O.D.; Landingham, R.L.

1995-08-29

Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50 C above the A{sub 1} transformation temperature, soaking the steel above the A{sub 1} temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature. 9 figs.

Transformation process for production of ultrahigh carbon steels and new alloys

DOEpatents

Strum, Michael J.; Goldberg, Alfred; Sherby, Oleg D.; Landingham, Richard L.

1995-01-01

Ultrahigh carbon steels with superplastic properties are produced by heating a steel containing ferrite and carbide phases to a soaking temperature approximately 50.degree. C. above the A.sub.1 transformation temperature, soaking the steel above the A.sub.1 temperature for a sufficient time that the major portion of the carbides dissolve into the austenite matrix, and then cooling the steel in a controlled manner within predetermined limits of cooling rate or transformation temperature, to obtain a steel having substantially spheroidal carbides. New alloy compositions contain aluminum and solute additions which promote the formation of a fine grain size and improve the resistance of the carbides to coarsening at the forming temperature.

Standard specification for carbon and alloy steel nuts. ASTM standard

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

This specification is under the jurisdiction of ASTM Committee F-16 on Fasteners and is the responsibility of Subcommittee F16.02 on Steel Bolts, Nuts, Rivets, and Washers. Current edition approved Dec. 10, 1997. Published July 1998. Originally published as A 563-66. Last previous edition A 563-96.

Alloy-steel nuts for bolting for high-pressure and high-temperature service (ASME SA-194 with additional requirements)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This standard covers alloy steel nuts for bolting for high-pressure and high-temperature service in nuclear and associated applications. This standard does not cover bar or other starting materials. The only implied special considerations for starting materials are that they be capable of passing the required tests when processed into finished products in accordance with this standard. Material shall conform to the requirements of ASME SA-194; to the requirements of the ASME Boiler and Pressure Vessel Code (ASME Code), Section III, Article NB-2000; to the requirements of NE E 8-18; and to the additional requirements of this standard.

78 FR 63450 - Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico, Moldova, Trinidad and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-24

...-805, A-274-804, A-823-812] Carbon and Certain Alloy Steel Wire Rod From Brazil, Indonesia, Mexico... on carbon and certain alloy steel wire rod (``wire rod'') from Brazil, Indonesia, Mexico, Moldova... published the notice of initiation of the sunset reviews of the antidumping duty orders on wire rod from...

Peculiarities of steel and alloy electrochemical and corrosion behavior after laser processing

NASA Astrophysics Data System (ADS)

Kuzmenko, Tat'yana G.; Kosyrev, Feliks K.; Rodin, Anatoly V.; Sayapin, V. P.

1997-04-01

Different types of laser processing can significantly increase the corrosion resistance of constructive materials, secure higher levels of metal properties in comparison with standard protection from corrosion and can be successfully used for industrial application. The research carried out in TRINITI during the last 10 years allowed us to create a data base about corrosion behavior in different chemical media of various metals, alloys and steels after welding, melting, surface alloying, etc. on technological continuous-wave carbon-dioxide-laser with average power up to 5 kilowatt. The investigated materials were subdivided into two groups: (1) without changes of phases composition after laser processing (pure metals, stainless steels); and (2) exposed to structural and phase changes under laser-matter interaction (carbon steels with different carbon content). It has allowed us to investigate the peculiarities of corrosion process mechanism depending on matter surface structure and phase composition both on laser irradiation regimes. Our research was based on the high sensitive electrochemical analysis combined with other corrosion and physical methods. The essential principles of electrochemical analysis are next. There are two main processes on metal under the interaction with electrolyte solution: anodic reaction -- which means the metal oxidation or transition of metal kations into solution; cathodic reaction -- the reoxidation of the ions or molecular of the solution. They are characterizing by the values of current densities and the rates of these reactions are dependent upon the potential arising on the metal-solution frontier. The electrochemical reactions kinetic investigations gives a unique possibility for the research of metal structure and corrosion behavior even in the case of small thickness of laser processed layers.

The corrosion performance of high chromium stainless steels and titanium alloys at a reverse osmosis plant in Arabian Gulf seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Odwani, A.; Al-Tabatabaei, M.; Carew, J.

1997-08-01

Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion performance of four high chromium stainless steels and Grade 2 titanium in flowing Arabian Gulf natural seawater. The EIS provided information concerning the changes to the interfacial impedance as a function of exposure time for these alloys. The impedance spectra for all the alloys showed slight changes at the low frequency region over the exposure period. The open-circuit potentials (OCP) of these alloys were also monitored as a function of exposure time. The stainless steel alloys exhibited slight fluctuation in potential around the initial exposure potential. However, Grade 2 titaniummore » initial potential was more active and then gradually shifted towards the noble direction. The linear polarization resistance (LPR) method indicated that Grade 2 titanium exhibited the lowest corrosion rate with respect to the stainless steel alloys. The results of the EIS analysis and OCP indicated that Grade 2 titanium performed better than the four high chromium stainless steel alloys.« less

Investigation of attenuation coefficients of some stainless steel and aluminum alloys

NASA Astrophysics Data System (ADS)

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.

Laser Overlap Welding of Zinc-coated Steel on Aluminum Alloy

NASA Astrophysics Data System (ADS)

Kashani, Hamed Tasalloti; Kah, Paul; Martikainen, Jukka

Local reinforcement of aluminum with laser welded patches of zinc-coated steel can effectively contribute to crashworthiness, durability and weight reduction of car body. However, the weld between Zn-coated steel and aluminum is commonly susceptible to defects such as spatter, cavity and crack. The vaporization of Zn is commonly known as the main source of instability in the weld pool and cavity formation, especially in a lap joint configuration. Cracks are mainly due to the brittle intermetallic compounds growing at the weld interface of aluminum and steel. This study provides a review on the main metallurgical and mechanical concerns regarding laser overlap welding of Zn-coated steel on Al-alloy and the methods used by researchers to avoid the weld defects related to the vaporization of Zn and the poor metallurgical compatibility between steel and aluminum.

Mechanical properties and oxidation and corrosion resistance of reduced-chromium 304 stainless steel alloys

NASA Technical Reports Server (NTRS)

Stephens, J. R.; Barrett, C. A.; Gyorgak, C. A.

1979-01-01

An experimental program was undertaken to identify effective substitutes for part of the Cr in 304 stainless steel as a method of conserving the strategic element Cr. Although special emphasis was placed on tensile properties, oxidation and corrosion resistance were also examined. Results indicate that over the temperature range of -196 C to 540 C the yield stress of experimental austenitic alloys with only 12 percent Cr compare favorably with the 18 percent Cr in 304 stainless steel. Oxidation resistance and in most cases corrosion resistance for the experimental alloys were comparable to the commercial alloy. Effective substitutes for Cr included Al, Mo, Si, Ti, and V, while Ni and Mn contents were increased to maintain an austenitic structure.

Surface and cut-edge corrosion behavior of Zn-Mg-Al alloy-coated steel sheets as a function of the alloy coating microstructure

NASA Astrophysics Data System (ADS)

Oh, Min-Suk; Kim, Sang-Heon; Kim, Jong-Sang; Lee, Jae-Won; Shon, Je-Ha; Jin, Young-Sool

2016-01-01

The effects of Mg and Al content on the microstructure and corrosion resistance of hot-dip Zn-Mg-Al alloycoated steel sheets were investigated. Pure Zn and Zn-based alloy coatings containing Mg (0-5 wt%) and Al (0.2-55 wt%) were produced by a hot-dip galvanizing method. Mg and Al addition induced formation of intermetallic microstructures, like primary Zn, Zn/MgZn2 binary eutectic, dendric Zn/Al eutectoid, and Zn/Al/MgZn2/ternary eutectic structures in the coating layer. MgZn2-related structures (Zn/MgZn2, Zn/Al/MgZn2, MgZn2) played an important role in increasing the corrosion resistance of Zn-Mg-Al alloy-coated steel sheets. Zn-3%Mg-2.5%Al coating layer containing a large volume of lamellar-shaped Zn/MgZn2 binary eutectic structures showed the best cut-edge corrosion resistance. The analysis indicated that Mg dissolved from MgZn2 in the early stage of corrosion and migrated to the cathodic region of steel-exposed cut-edge area to form dense and ordered protective corrosion products, leading to prolonged cathodic protection of Zn-Mg-Al alloy-coated steel sheets.

Impacts of Modification of Alloying Method on Inclusion Evolution in RH Refining of Silicon Steel

PubMed Central

Li, Huigai; Zheng, Shaobo; You, Jinglin; Han, Ke; Zhai, Qijie

2017-01-01

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. PMID:29048379

Medium-Alloy Manganese-Rich Transformation-Induced Plasticity Steels

NASA Astrophysics Data System (ADS)

Suh, Dong Woo; Ryu, Joo Hyun; Joo, Min Sung; Yang, Hong Seok; Lee, Kyooyoung; Bhadeshia, H. K. D. H.

2013-01-01

The manganese concentration of steels which rely on transformation-induced plasticity is generally less than 2 wt pct. Recent work has highlighted the potential for strong and ductile alloys containing some 6 wt pct of manganese, but with aluminum additions in order to permit heat treatments which are amenable to rapid production. However, large concentrations of aluminum also cause difficulties during continuous casting. Alloy design calculations have been carried out in an effort to balance these conflicting requirements, while maintaining the amount of retained austenite and transformation kinetics. The results indicate that it is possible by adjusting the carbon and manganese concentrations to reduce the aluminum concentration, without compromising the mechanical properties or transformation kinetics. The deformation-induced transformation of retained austenite is explained quantitatively, for a range of alloys, in terms of a driving force which takes into account the very fine state of the retained austenite.

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

Federal Register 2010, 2011, 2012, 2013, 2014

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...

Microstructure design of low alloy transformation-induced plasticity assisted steels

NASA Astrophysics Data System (ADS)

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

Influence of the pulsed plasma treatment on the corrosion resistance of the low-alloy steel plated by Ni-based alloy

NASA Astrophysics Data System (ADS)

Dzhumaev, P.; Yakushin, V.; Kalin, B.; Polsky, V.; Yurlova, M.

2016-04-01

This paper presents investigation results of the influence of high temperature pulsed plasma flows (HTPPF) treatment on the corrosion resistance of low-alloy steel 0.2C-Cr-Mn- Ni-Mo cladded by the rapidly quenched nickel-based alloy. A technique that allows obtaining a defect-free clad layer with a good adhesion to the substrate was developed. It is shown that the preliminary treatment of steel samples by nitrogen plasma flows significantly increases their corrosion resistance in the conditions of intergranular corrosion test in a water solution of sulfuric acid. A change of the corrosion mechanism of the clad layer from intergranular to uniform corrosion was observed as a result of sub-microcrystalline structure formation and homogeneous distribution of alloying elements in the plasma treated surface layer thus leading to the significant increase of the corrosion resistance.

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

NASA Astrophysics Data System (ADS)

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.

Simultaneous material flow analysis of nickel, chromium, and molybdenum used in alloy steel by means of input-output analysis.

PubMed

Nakajima, Kenichi; Ohno, Hajime; Kondo, Yasushi; Matsubae, Kazuyo; Takeda, Osamu; Miki, Takahiro; Nakamura, Shinichiro; Nagasaka, Tetsuya

2013-05-07

Steel is not elemental iron but rather a group of iron-based alloys containing many elements, especially chromium, nickel, and molybdenum. Steel recycling is expected to promote efficient resource use. However, open-loop recycling of steel could result in quality loss of nickel and molybdenum and/or material loss of chromium. Knowledge about alloying element substance flow is needed to avoid such losses. Material flow analyses (MFAs) indicate the importance of steel recycling to recovery of alloying elements. Flows of nickel, chromium, and molybdenum are interconnected, but MFAs have paid little attention to the interconnected flow of materials/substances in supply chains. This study combined a waste input-output material flow model and physical unit input-output analysis to perform a simultaneous MFA for nickel, chromium, and molybdenum in the Japanese economy in 2000. Results indicated the importance of recovery of these elements in recycling policies for end-of-life (EoL) vehicles and constructions. Improvement in EoL sorting technologies and implementation of designs for recycling/disassembly at the manufacturing phase are needed. Possible solutions include development of sorting processes for steel scrap and introduction of easier methods for identifying the composition of secondary resources. Recovery of steel scrap with a high alloy content will reduce primary inputs of alloying elements and contribute to more efficient resource use.

Process for dezincing galvanized steel

DOEpatents

Morgan, W.A.; Dudek, F.J.; Daniels, E.J.

1998-07-14

A process is described for removing zinc from galvanized steel. The galvanized steel is immersed in an electrolyte containing at least about 15% by weight of sodium or potassium hydroxide and having a temperature of at least about 75 C and the zinc is galvanically corroded from the surface of the galvanized steel. The material serving as the cathode is principally a material having a standard electrode potential which is intermediate of the standard electrode potentials of zinc and cadmium in the electrochemical series. The corrosion rate may be accelerated by (1) increasing the number density of corrosion sites in the galvanized steel by mechanically abrading or deforming the galvanized steel, (2) heating the galvanized steel to form an alloy of zinc on the surface of the galvanized steel, (3) mixing the galvanized steel with a material having a standard electrode potential which is intermediate of the standard electrode potentials of zinc and cadmium in the electrochemical series, or (4) moving the galvanized steel relative to itself and to the electrolyte while immersed in the electrolyte. 1 fig.

Process for dezincing galvanized steel

DOEpatents

Morgan, William A.; Dudek, Frederick J.; Daniels, Edward J.

1998-01-01

A process for removing zinc from galvanized steel. The galvanized steel is immersed in an electrolyte containing at least about 15% by weight of sodium or potassium hydroxide and having a temperature of at least about 75.degree. C. and the zinc is galvanically corroded from the surface of the galvanized steel. The material serving as the cathode is principally a material having a standard electrode potential which is intermediate of the standard electrode potentials of zinc and cadmium in the electrochemical series. The corrosion rate may be accelerated by (i) increasing the number density of corrosion sites in the galvanized steel by mechanically abrading or deforming the galvanized steel, (ii) heating the galvanized steel to form an alloy of zinc on the surface of the galvanized steel, (iii) mixing the galvanized steel with a material having a standard electrode potential which is intermediate of the standard electrode potentials of zinc and cadmium in the electrochemical series, or (iv) moving the galvanized steel relative to itself and to the electrolyte while immersed in the electrolyte.

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

NASA Astrophysics Data System (ADS)

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.

76 FR 34044 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Extension of Time Limits for the Preliminary...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-10

... DEPARTMENT OF COMMERCE International Trade Administration [A-201-830] Carbon and Certain Alloy Steel Wire Rod From Mexico: Extension of Time Limits for the Preliminary Results of Fifth Antidumping... carbon and certain alloy steel wire rod from Mexico, covering the period October 1, 2009, through...

Effect of alloy composition on high-temperature bending fatigue strength of ferritic stainless steels

NASA Astrophysics Data System (ADS)

Ahn, Yong-Sik; Song, Jeon-Young

2011-12-01

Exhaust manifolds are subjected to an environment in which heating and cooling cycles occur due to the running pattern of automotive engines. This temperature profile results in the repeated bending stress of exhaust pipes. Therefore, among high-temperature characteristics, the bending fatigue strength is an important factor that affects the lifespan of exhaust manifolds. Here, we report on the effect of the alloy composition, namely the weight fraction of the elements Cr, Mo, Nb, and Ti, on the high-temperature bending fatigue strength of the ferritic stainless steel used in exhaust manifolds. Little difference in the tensile strength and bending fatigue strength of the different composition steels was observed below 600 °C, with the exception of the low-Cr steel. However, steels with high Cr, Mo, or Nb fractions showed considerably larger bending fatigue strength at temperatures of 800 °C. After heating, the precipitates from the specimens were extracted electrolytically and analyzed using scanning electron microscopy energy dispersive spectrometry and transmission electron microscopy. Alloying with Cr and Mo was found to increase the bending fatigue strength due to the substitutional solid solution effect, while alloying with Nb enhanced the strength by forming fine intermetallic compounds, including NbC and Fe2Nb.

Local thermal expansions and lattice strains in Elinvar and stainless steel alloys

NASA Astrophysics Data System (ADS)

Yokoyama, Toshihiko; Koide, Akihiro; Uemura, Yohei

2018-02-01

Local thermal expansions and lattice strains in the Elinvar alloy Fe49.66Ni42.38Cr5.49Ti2.47 (Ni Span C) and the stainless steel SUS304 Fe71.98Ni9.07Cr18.09Mn0.86 (AISI304) were investigated by the temperature-dependent Cr, Fe, and Ni K -edge extended x-ray absorption fine-structure (EXAFS) measurements, combined with the path-integral effective classical potential Monte Carlo (PIECP MC) theoretical simulations. From the EXAFS analysis of the Elinvar alloy, the local thermal expansion around Fe is found to be considerably smaller than the ones around Ni and Cr. This observation can be understood simply because Fe in the Elinvar alloy exhibit an incomplete Invar-like effect. Moreover, in both the Elinvar and SUS304 alloys, the local thermal expansions and the lattice strains around Cr are found to be larger than those around Fe and Ni. From the PIECP MC simulations of both the alloys, the first-nearest neighbor Cr-Fe pair shows extraordinarily large thermal expansion, while the Cr-Cr pair exhibits quite small or even negative thermal expansion. These findings consequently indicate that the lattice strains in both the Elinvar and SUS304 alloys are concentrated predominantly on the Cr atoms. Although the role of Cr in stainless steel has been known to inhibit corrosion by the formation of surface chromium oxide, the present investigation may interestingly suggest that the Cr atoms in the bulk play a hidden new role of absorbing inevitable lattice strains in the alloys.

Prediction of Contact Fatigue Life of Alloy Cast Steel Rolls Using Back-Propagation Neural Network

NASA Astrophysics Data System (ADS)

Jin, Huijin; Wu, Sujun; Peng, Yuncheng

2013-12-01

In this study, an artificial neural network (ANN) was employed to predict the contact fatigue life of alloy cast steel rolls (ACSRs) as a function of alloy composition, heat treatment parameters, and contact stress by utilizing the back-propagation algorithm. The ANN was trained and tested using experimental data and a very good performance of the neural network was achieved. The well-trained neural network was then adopted to predict the contact fatigue life of chromium alloyed cast steel rolls with different alloy compositions and heat treatment processes. The prediction results showed that the maximum value of contact fatigue life was obtained with quenching at 960 °C, tempering at 520 °C, and under the contact stress of 2355 MPa. The optimal alloy composition was C-0.54, Si-0.66, Mn-0.67, Cr-4.74, Mo-0.46, V-0.13, Ni-0.34, and Fe-balance (wt.%). Some explanations of the predicted results from the metallurgical viewpoints are given. A convenient and powerful method of optimizing alloy composition and heat treatment parameters of ACSRs has been developed.

Frictional conditions between alloy AA6060 aluminium and tool steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wideroee, Fredrik; Welo, Torgeir

The frictional conditions in the new process of screw extrusion of aluminium have been investigated. The contact behaviour between the aluminum alloy and the tool steel in the extruder is vital for understanding the extrusion process. Using a compressive-rotational method for frictional measurements the conditions for unlubricated sticking friction between aluminum alloy AA6060 and tool steel at different combinations of temperatures and pressures have been investigated. In this method the samples in the form of disks are put under hydrostatic pressure while simultaneously being rotated at one end. Pins made from contrast material have been inserted into the samples tomore » measure the deformation introduced. This approach along with 3D simulations form a method for determining the frictional conditions. The paper describes the test method and the results. It was found that the necessary pressure for sticking to occur between the aluminum AA6060 and the different parts of the extruder is heavily influenced by the temperature.« less

Evaluation of Stress Corrosion Cracking Susceptibility Using Fracture Mechanics Techniques, Part 1. [environmental tests of aluminum alloys, stainless steels, and titanium alloys

NASA Technical Reports Server (NTRS)

Sprowls, D. O.; Shumaker, M. B.; Walsh, J. D.; Coursen, J. W.

1973-01-01

Stress corrosion cracking (SSC) tests were performed on 13 aluminum alloys, 13 precipitation hardening stainless steels, and two titanium 6Al-4V alloy forgings to compare fracture mechanics techniques with the conventional smooth specimen procedures. Commercially fabricated plate and rolled or forged bars 2 to 2.5-in. thick were tested. Exposures were conducted outdoors in a seacoast atmosphere and in an inland industrial atmosphere to relate the accelerated tests with service type environments. With the fracture mechanics technique tests were made chiefly on bolt loaded fatigue precracked compact tension specimens of the type used for plane-strain fracture toughness tests. Additional tests of the aluminum alloy were performed on ring loaded compact tension specimens and on bolt loaded double cantilever beams. For the smooth specimen procedure 0.125-in. dia. tensile specimens were loaded axially in constant deformation type frames. For both aluminum and steel alloys comparative SCC growth rates obtained from tests of precracked specimens provide an additional useful characterization of the SCC behavior of an alloy.

PERFORMANCE IMPROVEMENT OF CREEP-RESISTANT FERRITIC STEEL WELDMENTS THROUGH THERMO-MECHANICAL TREATMENT AND ALLOY DESIGN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamamoto, Yukinori; Babu, Prof. Sudarsanam Suresh; Shassere, Benjamin

Two different approaches have been proposed for improvement of cross-weld creep properties of the high temperature ferrous structural materials for fossil-fired energy applications. The traditional creep strength-enhanced ferritic (CSEF) steel weldments suffer from Type IV failures which occur at the fine-grained heat affected zone (FGHAZ). In order to minimize the premature failure at FGHAZ in the existing CSEF steels, such as modified 9Cr-1Mo ferritic-martensitic steels (Grade 91), a thermo-mechanical treatment consisting of aus-forging/rolling and subsequent aus-aging is proposed which promotes the formation of stable MX carbonitrides prior to martensitic transformation. Such MX remains undissolved during welding process, even in FGHAZ,more » which successfully improves the cross-weld creep properties. Another approach is to develop a new fully ferrtic, creep-resistant FeCrAl alloy which is essentially free from Type IV failure issues. Fe-30Cr-3Al base alloys with minor alloying additions were developed which achieved a combination of good oxidation/corrosion resistance and improved tensile and creep performance comparable or superior to Grade 92 steel.« less

Role of alloy additions on strengthening in 17-4 PH stainless steel

NASA Astrophysics Data System (ADS)

Murthy, Arpana Sudershan

Alloy modifications by addition of niobium (Nb), vanadium (V), nitrogen (N) and cobalt (Co) to cast 17-4 PH steel were investigated to determine the effect on mechanical properties. Additions of Nb, V, and N increased the yield strength from 1120 MPa to 1310 MPa while decreased the room temperature charpy V notch (CVN) toughness from 20 J to four Joules. The addition of Co to cast 17-4 PH steel enhanced the yield strength and CVN toughness from 1140 MPa to 1290 MPa and from 3.7 J to 5.5 J, respectively. In the base 17-4 PH steel, an increase in block width from 2.27 ± 0.10 μm in the solution treated condition to 3.06 ± 0.17 μm upon aging at 755 K was measured using orientation image microscopy. Cobalt inhibited recrystallization and block boundary migration during aging resulting in a finer martensitic block structure. The influence of Co on copper (Cu) precipitation in steels was studied using atom probe tomography. A narrower precipitate size distribution was observed in the steels with Co addition. The concentration profile across the matrix / precipitate interface indicated rejection of Co atoms from the copper precipitates. This behavior was observed to be energetically favorable using first principle calculations. The activation energies for Cu precipitation increased from 205 kJ/ mol in the non-cobalt containing alloy, to 243 kJ/ mol, and 272 kJ/ mol in alloys with 3 wt. %Co, and 7 wt. % Co, respectively. The role of Co on Cu precipitation in cast 17-4 PH steel is proposed as follows: (i) Co is rejected out of the Cu precipitate and sets up a barrier to the growth of the Cu precipitate; (ii) results in Cu precipitates of smaller size and narrower distribution; (iii) the coarsening of Cu precipitates is inhibited; and (iv) the activation energy for Cu precipitation increases.

Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel.

PubMed

Song, Sol-Ji; Kim, Jung-Gu

2018-01-20

This study examined the synergic effect of alloying the element Cr and the environmental element Mg 2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) tests and weight-loss tests. The Mg 2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg 2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe₂O₄ and a mixed layer (Cr oxide + FeCr₂O₄ + MgCr₂O₄) improved the corrosion resistance of the low-alloy steel in the seawater.

Resistance Element Welding of Magnesium Alloy/austenitic Stainless Steel

NASA Astrophysics Data System (ADS)

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.

49 CFR 178.512 - Standards for steel or aluminum boxes.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for steel or aluminum boxes. 178.512... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.512 Standards for steel or aluminum boxes. (a) The following are identification codes for steel or aluminum boxes: (1) 4A for a steel box; and...

49 CFR 178.512 - Standards for steel or aluminum boxes.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for steel or aluminum boxes. 178.512... FOR PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.512 Standards for steel or aluminum boxes. (a) The following are identification codes for steel or aluminum boxes: (1) 4A for a steel...

49 CFR 178.512 - Standards for steel or aluminum boxes.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for steel or aluminum boxes. 178.512... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.512 Standards for steel or aluminum boxes. (a) The following are identification codes for steel or aluminum boxes: (1) 4A for a steel box; and...

Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

NASA Astrophysics Data System (ADS)

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.

Correlation of the thermodynamic calculation and the experimental observation of Ni-Mo-Cr low alloy steel changing Ni, Mo, and Cr contents

NASA Astrophysics Data System (ADS)

Park, Sang-Gyu; Kim, Min-Chul; Lee, Bong-Sang; Wee, Dang-Moon

2010-12-01

SA508 Gr.4N Ni-Mo-Cr low alloy steel has improved fracture toughness and strength compared to commercial low alloy steels such as SA508 Gr.3 Mn-Mo-Ni low alloy steel, which has less than 1% Ni. Higher strength and fracture toughness of low alloy steels can be achieved by increasing the Ni and Cr contents. In this study, the effects of the alloying elements of Ni and Cr on the microstructural characteristics and mechanical properties of SA508 Gr.4N Ni-Mo-Cr low alloy steel are evaluated. Changes in the stable phases of SA508 Gr.4N low alloy steel with these alloying elements were evaluated using thermodynamic calculation software. These values were then compared with the observed microstructural results. Additionally, tensile tests and Charpy impact test were carried out to evaluate the mechanical properties. The thermodynamic calculations show that Ni mainly affects the change of the matrix phase of γ and α rather than the carbide phase. Contrary to the Ni effect, Cr and Mo primarily affect the precipitation behavior of the carbide phases of Cr 23C 6, Cr 7C 3 and Mo 2C. In the microscopic observations, the lath martensitic structure becomes finer as the Ni content increases without affecting the carbides. When the Cr content decreases, the Cr carbide becomes unstable and carbide coarsening occurs. Carbide Mo 2C in the form of fine needles were observed in the high-Mo alloy. Greater strength was obtained after additions of Ni and Mo and the transition properties were improved as the Ni and Cr contents increased. These results were correlated with the thermodynamic calculation results.

Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel

PubMed Central

Song, Sol-Ji; Kim, Jung-Gu

2018-01-01

This study examined the synergic effect of alloying the element Cr and the environmental element Mg2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) tests and weight-loss tests. The Mg2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe2O4 and a mixed layer (Cr oxide + FeCr2O4 + MgCr2O4) improved the corrosion resistance of the low-alloy steel in the seawater. PMID:29361710

Pitting corrosion resistance of a novel duplex alloy steel in alkali-activated slag extract in the presence of chloride ions

NASA Astrophysics Data System (ADS)

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.

Effects of stress ratio on the temperature-dependent high-cycle fatigue properties of alloy steels

NASA Astrophysics Data System (ADS)

Lü, Zhi-yang; Wan, Ao-shuang; Xiong, Jun-jiang; Li, Kuang; Liu, Jian-zhong

2016-12-01

This paper addresses the effects of stress ratio on the temperature-dependent high-cycle fatigue (HCF) properties of alloy steels 2CrMo and 9CrCo, which suffer from substantial vibrational loading at small stress amplitude, high stress ratio, and high frequency in the high-temperature environments in which they function as blade and rotor spindle materials in advanced gas or steam turbine engines. Fatigue tests were performed on alloy steels 2CrMo and 9CrCo subjected to constant-amplitude loading at four stress ratios and at four and three temperatures, respectively, to determine their temperature-dependent HCF properties. The interaction mechanisms between high temperature and stress ratio were deduced and compared with each other on the basis of the results of fractographic analysis. A phenomenological model was developed to evaluate the effects of stress ratio on the temperature-dependent HCF properties of alloy steels 2CrMo and 9CrCo. Good correlation was achieved between the predictions and actual experiments, demonstrating the practical and effective use of the proposed method.

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Quantifying Recycling and Losses of Cr and Ni in Steel Throughout Multiple Life Cycles Using MaTrace-Alloy.

PubMed

Nakamura, Shinichiro; Kondo, Yasushi; Nakajima, Kenichi; Ohno, Hajime; Pauliuk, Stefan

2017-09-05

Alloying metals are indispensable ingredients of high quality alloy steel such as austenitic stainless steel, the cyclical use of which is vital for sustainable resource management. Under the current practice of recycling, however, different metals are likely to be mixed in an uncontrolled manner, resulting in function losses and dissipation of metals with distinctive functions, and in the contamination of recycled steels. The latter could result in dilution loss, if metal scrap needed dilution with virgin iron to reduce the contamination below critical levels. Management of these losses resulting from mixing in repeated recycling of metals requires tracking of metals over multiple life cycles of products with compositional details. A new model (MaTrace-alloy) was developed that tracks the fate of metals embodied in each of products over multiple life cycles of products, involving accumulation, discard, and recycling, with compositional details at the level of both alloys and products. The model was implemented for the flow of Cr and Ni in the Japanese steel cycle involving 27 steel species and 115 final products. It was found that, under a high level of scrap sorting, greater than 70% of the initial functionality of Cr and Ni could be retained over a period of 100 years, whereas under a poor level of sorting, it could plunge to less than 30%, demonstrating the relevance of waste management technology in circular economy policies.

Oxidation and corrosion behavior of modified-composition, low-chromium 304 stainless steel alloys

NASA Technical Reports Server (NTRS)

Stephens, J. R.; Barrett, C. A.

1977-01-01

The effects of substituting less strategic elements than Cr on the oxidation and corrosion resistance of AISI 304 stainless steel were investigated. Cyclic oxidation resistance was evaluated at 870 C. Corrosion resistance was determined by exposure of specimens to a boiling copper-rich solution of copper sulfate and sulfuric acid. Alloy substitutes for Cr included Al, Mn, Mo, Si, Ti, V, Y, and misch metal. A level of about 12% Cr was the minimum amount of Cr required for adequate oxidation and corrosion resistance in the modified composition 304 stainless steels. This represents a Cr saving of at least 33%. Two alloys containing 12% Cr and 2% Al plus 2% Mo and 12% Cr plus 2.65% Si were identified as most promising for more detailed evaluation.

[Studies on the recovery of pharmaceutical drug substances from surfaces made of defined stainless-steel alloys].

PubMed

Kloss, S; Müller, U; Oelschläger, H

2005-09-01

Facilities for the manufacturing of pharmaceutical drug substances on the pilot-plant and the industrial scale as well as chemical reactors and vessels used for chemical work-up mainly consist of alloyed stainless steel. The influence of the alloy composition and the surface condition, i.e. of the roughness of the stainless-steel materials, on the adsorption of structurally diverse steroidal substances and, hence, on the quality of the products was studied. In general, stainless-steel alloys with smooth, not so rough surfaces are to be favored as reactor material. However, it was demonstrated in this study that, on account of the weak interaction between active substances and steel materials, mechanically polished materials of a medium roughness up to approx. 0.4 microm can be employed instead of the considerably more cost-intensive electrochemically polished stainless-steel surfaces. The type of surface finishing up to a defined roughness, then, has no influence on the quality of these pharmaceutical products. Substances that, because of their molecular structure, can function as "anions" in the presence of polar solvents, are adsorbed on very smooth surfaces prepared by electrochemical methods, forming an amorphous surface film. For substances with this structural characteristics, the lower-cost mechanically polished reactor materials of a medium roughness up to approx. 0.5 microm should be used exclusively.

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

NASA Technical Reports Server (NTRS)

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.

Metallic ions released from stainless steel, nickel-free, and titanium orthodontic alloys: toxicity and DNA damage.

PubMed

Ortiz, Antonio José; Fernández, Esther; Vicente, Ascensión; Calvo, José L; Ortiz, Clara

2011-09-01

The aims of this study were to determine the amounts of metallic ions that stainless steel, nickel-free, and titanium alloys release to a culture medium, and to evaluate the cellular viability and DNA damage of cultivated human fibroblasts with those mediums. The metals were extracted from 10 samples (each consisting of 4 buccal tubes and 20 brackets) of the 3 orthodontic alloys that were submerged for 30 days in minimum essential medium. Next, the determination of metals was performed by using inductively coupled plasma mass spectrometry, cellular viability was assessed by using the tetrazolium reduction assay (MTT assay) (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide), and DNA damage was determined with the Comet assay. The metals measured in all the samples were Ti(47), Cr(52), Mn(55), Co(59), Ni(60), Mo(92), Fe(56), Cu(63), Zn(66), As(75), Se(78), Cd(111), and Pb(208). The cellular viability of the cultured fibroblasts incubated for 7 days with minimum essential medium, with the stainless steel alloy submerged, was close to 0%. Moreover, high concentrations of titanium, chromium, manganese, cobalt, nickel, molybdenum, iron, copper, and zinc were detected. The nickel-free alloy released lower amounts of ions to the medium. The greatest damage in the cellular DNA, measured as the olive moment, was also produced by the stainless steel alloy followed by the nickel-free alloy. Conversely, the titanium alloy had an increased cellular viability and did not damage the cellular DNA, as compared with the control values. The titanium brackets and tubes are the most biocompatible of the 3 alloys studied. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Attack polish for nickel-base alloys and stainless steels

DOEpatents

Steeves, Arthur F.; Buono, Donald P.

1983-01-01

A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels. The chemical attack polish comprises Fe(NO.sub.3).sub.3, concentrated CH.sub.3 COOH, concentrated H.sub.2 SO.sub.4 and H.sub.2 O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

Method of polishing nickel-base alloys and stainless steels

DOEpatents

Steeves, Arthur F.; Buono, Donald P.

1981-01-01

A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels. The chemical attack polish comprises Fe(NO.sub.3).sub.3, concentrated CH.sub.3 COOH, concentrated H.sub.2 SO.sub.4 and H.sub.2 O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

Attack polish for nickel-base alloys and stainless steels

DOEpatents

Not Available

1980-05-28

A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels is described. The chemical attack polich comprises FeNO/sub 3/, concentrated CH/sub 3/COOH, concentrated H/sub 2/SO/sub 4/ and H/sub 2/O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

Nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel and stainless steel alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, D.G.; Sorensen, N.R.

1998-02-01

This report presents a nondestructive inspection assessment of eddy current and electrochemical analysis to separate inconel alloys from stainless steel alloys as well as an evaluation of cleaning techniques to remove a thermal oxide layer on aircraft exhaust components. The results of this assessment are presented in terms of how effective each technique classifies a known exhaust material. Results indicate that either inspection technique can separate inconel and stainless steel alloys. Based on the experiments conducted, the electrochemical spot test is the optimum for use by airframe and powerplant mechanics. A spot test procedure is proposed for incorporation into themore » Federal Aviation Administration Advisory Circular 65-9A Airframe & Powerplant Mechanic - General Handbook. 3 refs., 70 figs., 7 tabs.« less

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

NASA Astrophysics Data System (ADS)

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.

A comparative study of the in vitro corrosion behavior and cytotoxicity of a superferritic stainless steel, a Ti-13Nb-13Zr alloy, and an austenitic stainless steel in Hank's solution.

PubMed

Assis, S L; Rogero, S O; Antunes, R A; Padilha, A F; Costa, I

2005-04-01

In this study, the in vitro corrosion resistance of a superferritic stainless steel in naturally aerated Hank's solution at 37 degrees C has been determined to evaluate the steel for use as a biomaterial. The potentiodynamic polarization method and electrochemical impedance spectroscopy (EIS) were used to determine the corrosion resistance. The polarization results showed very low current densities at the corrosion potential and electrochemical behavior typical of passive metals. At potentials above 0.75 V (SCE), and up to that of the oxygen evolution reaction, the superferritic steel exhibited transpassive behavior followed by secondary passivation. The superferritic stainless steel exhibited high pitting resistance in Hank's solution. This steel did not reveal pits even after polarization to 3000 mV (SCE). The EIS results indicated high impedance values at low frequencies, supporting the results obtained from the polarization measurements. The results obtained for the superferritic steel have been compared with those of the Ti-13Nb-13Zr alloy and an austenitic stainless steel, as Ti alloys are well known for their high corrosion resistance and biocompatibility, and the austenitic stainless steel is widely used as an implant material. The cytotoxicity tests indicated that the superferritic steel, the austenitic steel, and the Ti-13Nb-13Zr alloy were not toxic. Based on corrosion resistance and cytotoxicity results, the superferritic stainless steel can be considered as a potential biomaterial. (c) 2005 Wiley Periodicals, Inc.

Hydrogen adsorption and diffusion, and subcritical-crack growth in high-strength steels and nickel base alloys

NASA Technical Reports Server (NTRS)

Wei, R. P.; Klier, K.; Simmons, G. W.

1974-01-01

Coordinated studies of the kinetics of crack growth and of hydrogen adsorption and diffusion were initiated to develop information that is needed for a clearer determination of the rate controlling process and possible mechanism for hydrogen enhanced crack growth, and for estimating behavior over a range of temperatures and pressures. Inconel 718 alloy and 18Ni(200) maraging steel were selected for these studies. 18Ni(250) maraging steel, 316 stainless steel, and iron single crystal of (111) orientation were also included in the chemistry studies. Crack growth data on 18Ni(250) maraging steel from another program are included for comparison. No sustained-load crack growth was observed for the Inconel 718 alloy in gaseous hydrogen. Gaseous hydrogen assisted crack growth in the 18Ni maraging steels were characterized by K-independent (Stage 2) extension over a wide range of hydrogen pressures (86 to 2000 torr or 12 kN/m2 to 266 kN/m2) and test temperatures (-60 C to +100 C). The higher strength 18Ni(250) maraging steel was more susceptible than the lower strength 200 grade. A transition temperature was observed, above which crack growth rates became diminishingly small.

STRESS CORROSION CRACKING OF ALLOY 152 WELD BUTTER NEAR THE LOW ALLOY STEEL INTERFACE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexandreanu, Bogdan; Chen, Yiren; Natesan, Ken

2015-01-01

The objective of this work was to obtain SCC growth data in Alloy 152 weld butter near the interface with Low Alloy Steel (LAS), which is a region where some dilution of Cr was expected to have occurred, thus presumably exhibiting an increased SCC-susceptibility vs. the bulk of the weld. The LAS piece used in this application was Alloy 533-Gr B from the Midland reactor lower head, and the Alloy 152 weld butter received a prototypical Post Weld Heat Treatment (PWHT) prior to joining by Alloy 152 to an Alloy 690 piece according to a procedure qualified to ASME IX.more » The compact tension specimens for SCC testing were aligned in the first layer of the Alloy 152 butter. The experimental approach based on tracking environmental enhancement vs. location was successful in identifying SCC-susceptible locations, and SCC rates ranging from 10-12 m/s to as high as 10-10 m/s were measured. The post-test examination of the specimens found that the fracture had the intergranular/interdendritic appearance typical of welds, and that the propagation was arrested wherever an intersection with the LAS occurred. The large range of SCC rates measured does not appear to correlate well with the local concentration of Cr (approx. 25% at the SCC locations), and, in fact, low Cr (20%) – high Fe “streaks” seemed to slow/arrest crack propagation. In short, simple “Cr dilution” does not seem to fully account for the “SCC-susceptible” microstructure that yielded the 10-10 m/s growth rate in this weld.« less

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

NASA Technical Reports Server (NTRS)

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.

Radiation damage studies of ion-irradiated low-activation developmental martensitic steel alloys for fusion applications

NASA Astrophysics Data System (ADS)

Mazey, D. J.; Hanks, W.; Lurcook, O. K.

1990-09-01

Five martensitic, nominally 9 and 11% Cr-W-V-Mn-Ta stainless steels which have been developed as low-activation alloys for fusion-reactor structural applications have been irradiated with 52 MeV Cr 6+ ions to 20 dpa at 475°C in the Harwell Variable Energy Cyclotron (VEC). Four of the alloys contained additions of 0.1 wt% Ta and these had been shown in prior tests to have mechanical properties comparable with the conventional FV 448 alloy. Examinations by TEM showed that irradiation-induced precipitates were present on a fine-scale in all of the alloys. These comprised Cr-rich lath-like defects in the 9Cr, Ta-free alloy; small Cr-rich particles in the 9Cr-3W-0.1Ta alloy and Cr-rich planar precipitates in the remaining alloys. Little or no irradiation-induced cavitation was observed. The other important irradiation-induced response was in the dislocation structure in the Ta-containing alloys which comprised an extensive rafted array of elongated a <100> type dislocation loops having major axes aligned in <100> directions. A significant fraction of the presumed a <100> loops contained stacking-fault fringes and analysis suggested that these were Cr 2N or Fe 4N nitride phase which it is known can form on {001} habit planes. Such nitrides are observed frequently under thermal-annealing conditions in ferritic steels, but less frequently under irradiation. Their formation in relation to the void swelling resistance of ferritic-martensitic alloys is discussed.

Alloying effect of copper on the corrosion properties of low-alloy steel for flue gas desulfurization system

NASA Astrophysics Data System (ADS)

Kim, Seon-Hong; Park, Sun-Ah; Kim, Jung-Gu; Shin, Kee-Sam; He, Yinsheng

2015-03-01

The alloying effect of Cu for a flue gas desulfurization materials was investigated using the electrochemical methods in the modified green death solution and the surface analyses. The test results demonstrated that the densely formed rust layer with high metallic Cu content improves the corrosion resistance of Cu-containing steel in the flue gas desulfurization (FGD) environment. The rust layer on the surface of the 0.02 wt% Cu steel, which has an insufficient Cu content, was less protective than others. The 0.05 wt% Cu steel represented the highest corrosion resistance due to the formation of the densely formed rust layer with optimum Cu content. Because the free standing Cu2S precipitates had the insoluble characteristic in highly acidic solution, it produced the relatively porous Cu-enriched layer on the 0.08 wt% Cu steel surface. From these phenomena, the corrosion resistance of specimen decreased as the Cu content of specimen increased from 0.05 wt% to 0.08 wt%.

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

NASA Astrophysics Data System (ADS)

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.

Corrosion and Fatigue Behavior of High-Strength Steel Treated with a Zn-Alloy Thermo-diffusion Coating

NASA Astrophysics Data System (ADS)

Mulligan, C. P.; Vigilante, G. N.; Cannon, J. J.

2017-11-01

High and low cycle fatigue tests were conducted on high-strength steel using four-point bending. The materials tested were ASTM A723 steel in the as-machined condition, grit-blasted condition, MIL-DTL-16232 heavy manganese phosphate-coated condition, and ASTM A1059 Zn-alloy thermo-diffusion coated (Zn-TDC). The ASTM A723 steel base material exhibits a yield strength of 1000 MPa. The effects of the surface treatments versus uncoated steel were examined. The fatigue life of the Zn-TDC specimens was generally reduced on as-coated specimens versus uncoated or phosphate-coated specimens. Several mechanisms are examined including the role of compressive residual stress relief with the Zn-TDC process as well as fatigue crack initiation from the hardened Zn-Fe alloy surface layer produced in the gas-metal reaction. Additionally, the effects of corrosion pitting on the fatigue life of coated specimens are explored as the Zn-TDC specimens exhibit significantly improved corrosion resistance over phosphate-coated and oiled specimens.

Ignition of steel alloys by impact of low-velocity iron/inert particles in gaseous oxygen

NASA Technical Reports Server (NTRS)

Benz, Frank J.; Mcilroy, Kenneth; Williams, Ralph E.

1988-01-01

The ignition of carbon steel and 316 and 304 stainless steels caused by the impact of low-velocity particles (a standard mixture consisting of 2 g of iron and 3 g of inert materials) in gaseous oxygen was investigated using NASA/White Sands Test Facility for the ignition test, and a subsonic particle impact chamber to accelerate the particles that were injected into flowing oxygen upstream of the target specimen. It was found that the oxygen velocities required to ignite the three alloys were the same as that required to ignite the particle mixture. Ignition occurred at oxygen velocities greater than 45 m/sec at 20 to 24 MPa and was found to be independent of pressure between 2 and 30 MPa. Comparison of the present results and the past results from Wegener (1964) with the Compressed Gas Association (CGA) oxygen velocity limits for safe operations indicates that the CGA limits may be excessively conservative at high pressures and too liberal at low pressures.

Use of steel and tantalum apparatus for molten Cd-Mg-Zn alloys

NASA Technical Reports Server (NTRS)

Bennett, G. A.; Burris, L., Jr.; Kyle, M. L.; Nelson, P. A.

1966-01-01

Steel and tantalum apparatus contains various ternary alloys of cadmium, zinc, and magnesium used in pyrochemical processes for the recovery of uranium-base reactor fuels. These materials exhibit good corrosion resistance at the high temperatures necessary for fuel separation in liquid metal-molten salt solvents.

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

PubMed Central

Matsushita, Masafumi

2011-01-01

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. PMID:28824144

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

NASA Astrophysics Data System (ADS)

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.

The effect of molten salt on high temperature behavior of stainless steel and titanium alloy with the presence of water vapor

NASA Astrophysics Data System (ADS)

Baharum, Azila; Othman, Norinsan Kamil; Salleh, Emee Marina

2018-04-01

The high temperature oxidation experiment was conducted to study the behavior of titanium alloy Ti6A14V and stainless steel 316 in Na2SO4-50%NaCl + Ar-20%O2 (molten salt) and Na2SO4-50%NaCl + Ar-20%O2 + 12% H2O (molten salt + water vapor) environment at 900°C for 30 hours using horizontal tube furnace. The sample then was investigated using weight change measurement analysis and X-ray diffraction (XRD) analysis to study the weight gained and the phase oxidation that occurred. The weight gained of the titanium alloy was higher in molten salt environment compared to stainless steel due to the rapid growth in the oxide scale but showed almost no change of weight gained upon addition of water vapor. This is due to the alloy was fully oxidized. Stainless steel showed more protection and better effect in molten salt environment compared to mixed environment showed by slower weight gain and lower oxidation rate. Meanwhile, the phase oxidation test of the samples showed that the titanium alloy consist of multi oxide layer of rutile (TiO2) and Al2O3 on the surface of the exposed sample. While stainless steel show the formation of both protective Cr-rich oxide and non-protective Fe-rich oxide layer. This can be concluded that stainless steel is better compared to Ti alloy due to slow growing of chromia oxide. Therefore it is proven that stainless steel has better self-protection upon high temperature exposure.

76 FR 78882 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Affirmative Preliminary Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-20

... Steel Wire Rod From Mexico: Affirmative Preliminary Determination of Circumvention of the Antidumping.... SUMMARY: We preliminarily determine that carbon and certain alloy steel wire rod (wire rod) with an actual.... de C.V. (Deacero) is circumventing the antidumping duty order on wire rod from Mexico (Wire Rod Order...

Dependence of magnetic permeability on residual stresses in alloyed steels

NASA Astrophysics Data System (ADS)

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.

77 FR 56809 - Certain Small Diameter Seamless Carbon and Alloy Steel Standard, Line, and Pressure Pipe From...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-14

... conveyance of water, steam, petrochemicals, chemicals, oil products, natural gas and other liquids and gasses... stress levels. Alloy pipes made to ASTM standard A-335 must be used if temperatures and stress levels... for the low temperature and pressure conveyance of water, steam, natural gas, air and other liquids...

Evaluation of advanced austenitic alloys relative to alloy design criteria for steam service

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swindeman, R.W.; Maziasz, P.J.; Bolling, E.

1990-05-01

The results are summarized for a 6-year activity on advanced austenitic stainless steels for heat recovery systems. Commercial, near-commercial, and developmental alloys were evaluated relative to criteria for metallurgical stability, fabricability, weldability, and mechanical strength. Fireside and steamside corrosion were also considered, but no test data were collected. Lean stainless steel alloys that were given special attention in the study were type 316 stainless steel, fine-grained type 347 stainless steel, 17-14CuMo stainless steel, Esshete 1250, Sumitomo ST3Cu{reg sign} stainless steel, and a group of alloys identified as HT-UPS (high-temperature, ultrafine-precipitation strengthened) steels that were basically 14Cr--16Ni--Mo steels modified by variousmore » additions of MC-forming elements. It was found that, by solution treating the MC-forming alloys to temperatures above 1150{degree}C and subsequently cold or warm working, excellent metallurgical stability and creep strength could be achieved. Test data to beyond 35,000 h were collected. The ability to clad the steels for improved fireside corrosion resistance was demonstrated. Weldability of the alloys was of concern, and hot cracking was found to be a problem in the HT-UPS alloys. By reducing the phosphorous content and selecting either CRE 16-8-2 stainless steel or alloy 556 filler metal, weldments were produced that had excellent strength and ductility. The major issues related to the development of the advanced alloys were identified and ways to resolve the issues suggested. 89 refs., 45 figs., 8 tabs.« less

Structural efficiencies of various aluminum, titanium, and steel alloys at elevated temperatures

NASA Technical Reports Server (NTRS)

Heimerl, George J; Hughes, Philip J

1953-01-01

Efficient temperature ranges are indicated for two high-strength aluminum alloys, two titanium alloys, and three steels for some short-time compression-loading applications at elevated temperatures. Only the effects of constant temperatures and short exposure to temperature are considered, and creep is assumed not to be a factor. The structural efficiency analysis is based upon preliminary results of short-time elevated-temperature compressive stress-strain tests of the materials. The analysis covers strength under uniaxial compression, elastic stiffness, column buckling, and the buckling of long plates in compression or in shear.

78 FR 2658 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Rescission of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-14

... Steel Wire Rod From Mexico: Rescission of Antidumping Duty Administrative Review; 2011-2012 AGENCY... order on carbon and certain alloy steel wire rod (``wire rod'') from Mexico for the period October 1... order on wire rod from Mexico for the period of review, October 1, 2011, through September 30, 2012.\\1...

Oxidation behavior and electrical property of ferritic stainless steel interconnects with a Cr-La alloying layer by high-energy micro-arc alloying process

NASA Astrophysics Data System (ADS)

Feng, Z. J.; Zeng, C. L.

Chromium volatility, poisoning of the cathode material and rapidly decreasing electrical conductivity are the major problems associated with the application of ferritic stainless steel interconnects of solid oxide fuel cells operated at intermediate temperatures. Recently, a novel and simple high-energy micro-arc alloying (HEMAA) process is proposed to prepare LaCrO 3-based coatings for the type 430 stainless steel interconnects using a LaCrO 3-Ni rod as deposition electrode. In this work, a Cr-La alloying layer is firstly obtained on the alloy surface by HEMAA using Cr and La as deposition electrode, respectively, followed by oxidation treatment at 850 °C in air to form a thermally grown LaCrO 3 coating. With the formation of a protective scale composed of a thick LaCrO 3 outer layer incorporated with small amounts of Cr-rich oxides and a thin Cr 2O 3-rich sub-layer, the oxidation rate of the coated steel is reduced remarkably. A low and stable electrical contact resistance is achieved with the application of LaCrO 3-based coatings, with a value less than 40 mΩ cm 2 during exposure at 850 °C in air for up to 500 h.

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

NASA Astrophysics Data System (ADS)

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.

Effect of Temperature and Dynamic Loading on the Mechanical Properties of Copper-Alloyed High-Strength Interstitial-Free Steel

NASA Astrophysics Data System (ADS)

Rana, R.; Singh, S. B.; Bleck, W.; Mohanty, O. N.

2009-04-01

Crash resistance and formability relevant mechanical properties of a copper-alloyed interstitial-free (IF) steel processed under various conditions of batch annealing (BA), continuous annealing (CA), and postcontinuous annealing aging have been studied in a wide range of strain rate (3.33 × 10-4 to 200 s-1) and temperature (-100 °C to +20 °C). These properties have been compared with similarly processed traditional mild and high-strength IF steels. Assessment of various parameters such as strength, elongation, strain rate sensitivity of stress, strain-hardening capacity, temperature sensitivity of stress, activation volume, and specific energy absorption of all these steels implies that copper-alloyed IF steel is soft and formable in CA condition. It can be made stronger and more crash resistant than the conventional mild- or high-strength IF steels when aged to peak strength after CA. Room-temperature strain rate sensitivity of stress of the investigated steels exhibits a two-stage behavior. Copper in solution in ferrite causes solid solution softening at low temperatures (≤20 °C) and at high strain rates (200 s-1).

Evaluation of pitting corrosion resistance of high-alloyed stainless steels welds for FGD plants in Korea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baek, K.K.; Sung, H.J.; Im, C.S.

1998-12-31

For successful application of high-alloyed stainless steels for Flue Gas Desulfurization (FGD) plants, pitting corrosion resistance of arc welds of N-added 6%Mo austenitic stainless steels (UNS N 08367) and super duplex stainless steels (UNS S 32550) made with various filler metals were evaluated using the Green Death solution. For Gas Tungsten Arc (GTA) and Gas Metal Arc (GMA) welds of N 08367, Critical Pitting Temperature (CPT) of base metal was 65--70 C, whereas weld made by ERNiCrMo-3 filler metal yielded CPT of 50 C. Welds made by ERNiCrMo-10 or ERNiCrMo-4 filler metals showed CPT of 60--65 C and 65--70C, respectively.more » For GTA and GMA welds of S 32550, CPT of welds made by ERNiCrMo-3 was 45--50 C, indicating that the filler metal can provide pitting corrosion resistance matching the S 32550 alloy. Thus, a proper pitting corrosion resistance of weldments of high-alloy stainless steels can be achieved by selecting filler metals having at least +10 higher Pitting Resistance Equivalent Number (PRE{sub N}) value than the base metal regardless of the type of arc welding process. The over-alloyed filler metals would compensate preferential segregation of Cr, MO along the dendrite boundary, which made the dendrite core more susceptible to pitting. Nitrogen addition to the GTA welds of N 08367 made with ERNiCrMo-3 failed to improve pitting corrosion resistance, which was attributed to the precipitation of nitrogen in the weld metal in the form of Nb-nitride.« less

Synthesis Oxide Dispersion Strengthening Stainless Steel doped with Nano Zirconia by Mechanical Alloying

NASA Astrophysics Data System (ADS)

Pawawoi; Widiansyah, Irfan; Hadi Prajitno, Djoko

2017-01-01

The oxide dispersion strengthening stainless steel of Fe-11.5wt%Cr and Fe-11.5wt%Cr-1%ZrO2 alloy by mechanical alloying method were synthesized by planetary ball milling. The methods employed for study were designing of Fe-11.5wt%Cr and Fe-11.5wt%Cr-1%ZrO2 proportion of composition alloy which is plotted to Schaffler diagram to get ferritic/martensitic stainless steel. After MA the ODS powders were compaction with pressure 80kg/mm2 and followed by sintering at the temperature of 900,1000 and 1100º C under high purity argon atmosphere for 1 hour. Characterization by XRD is used to examination phase present. Optical microscopy and SEM is used to get image microstructures. XRD analysis resulting the ferritic and martensitic is a major and minor phase respectively. There are not significant differences in the microstructure between Fe-11.5wt%Cr and Fe-11.5wt%Cr-1wt%ZrO2. An increase in the sintering temperature shift the microstructure from dendritic to equaxed. EDS examination showed that zirconia exit in the alloy Fe-11.5wt%Cr-1wt%ZrO2.The addition of 1 % nano-zirconia (ZrO2) into Fe-Cr alloy while milling process was resulted a higher Hardness Vickers Values rather than without zirconia addition. Average value of Hardness Vickers values was resulted 135.5 HV for Fe-11.5wt%Cr whereas 138.4 HV for Fe-11.5wt%Cr-1wt%ZrO2.

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

NASA Astrophysics Data System (ADS)

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.

Evaluation of the stress corrosion cracking resistance of several high strength low alloy steels

NASA Technical Reports Server (NTRS)

Humphries, T. S.; Nelson, E. E.

1980-01-01

The stress corrosion cracking resistance was studied for high strength alloy steels 4130, 4340, for H-11 at selected strength levels, and for D6AC and HY140 at a single strength. Round tensile and C-ring type specimens were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, salt spray, the atmosphere at Marshall Space Flight Center, and the seacoast at Kennedy Space Center. Under the test conditions, 4130 and 4340 steels heat treated to a tensile strength of 1240 MPa (180 ksi), H-11 and D6AC heat treated to a tensile strength of 1450 MPa (210 ksi), and HY140 (1020 MPa, 148 ksi) are resistant to stress corrosion cracking because failures were not encountered at stress levels up to 75 percent of their yield strengths. A maximum exposure period of one month for alternate immersion in salt water or salt spray and three months for seacoast is indicated for alloy steel to avoid false indications of stress corrosion cracking because of failure resulting from severe pitting.

Predictive analysis of the influence of the chemical composition and pre-processing regimen on structural properties of steel alloys using machine learning techniques

NASA Astrophysics Data System (ADS)

Krishnamurthy, Narayanan; Maddali, Siddharth; Romanov, Vyacheslav; Hawk, Jeffrey

We present some structural properties of multi-component steel alloys as predicted by a random forest machine-learning model. These non-parametric models are trained on high-dimensional data sets defined by features such as chemical composition, pre-processing temperatures and environmental influences, the latter of which are based upon standardized testing procedures for tensile, creep and rupture properties as defined by the American Society of Testing and Materials (ASTM). We quantify the goodness of fit of these models as well as the inferred relative importance of each of these features, all with a conveniently defined metric and scale. The models are tested with synthetic data points, generated subject to the appropriate mathematical constraints for the various features. By this we highlight possible trends in the increase or degradation of the structural properties with perturbations in the features of importance. This work is presented as part of the Data Science Initiative at the National Energy Technology Laboratory, directed specifically towards the computational design of steel alloys.

The Mechanical Property of Batch Annealed High Strength Low Alloy Steel HC260LA

NASA Astrophysics Data System (ADS)

Yang, Xiaojiang; Xia, Mingsheng; Zhang, Hongbo; Han, Bin; Li, Guilan

Cold rolled high strength low alloy steel is widely applied in the automotive parts due to its excellent formability and weldability. In this paper, the steel grade HC260LA according to European Norm was developed with batch annealing process. With commercial C-Mn mild steel as a benchmark, three different groups of chemistry namely C-Mn-Si, C-Mn-Nb-Ti and C-Mn-Nb were compared in terms of yield-tensile strength (Y/T) ratio. Microstructure and mechanical properties were characterized as well. Based on industrial production results, chemistry and detailed process parameters for batch annealing were identified. In the end the optimal Y/T ratio was proposed for this steel grade under batch annealing process.

Automatic flow system for simultaneous determination of iron and chromium in steel alloys employing photometers based on LEDs as radiation source

PubMed Central

Fernandes, Ridvan N.; Campos, Luís Fernando P.

2003-01-01

A multicommutated flow system for simultaneous determination of iron and chromium in steel alloys by photometry is described. The flow network consisted of an automatic injector and four solenoid valves assembled to form two independent analytical pathways, each one comprising reaction coils and a flow cell. The light source (LED) and detector (photodiode) were attached to the flow cells to form a compact unit. The flow system was microcomputer controlled by Quick BASIC 4.5 software, which carried out all steps of the analytical procedure. The feasibility of the system was proved by the determination of iron and chromium in steel alloys and its accuracy was accessed by comparing results with those obtained by plasma atomic emission spectrometry (ICP-AES). No significant difference at the 95% confidence level was observed. Other profitable features such as low reagent consumption (0.33 mg 1,10-phenantroline and 0.03 mg 1,5-diphenylcarbazide per determination); relative standard deviations (n = 5) of 0.4% for iron and 1.2% for chromium; and an analytical throughput of 160 determinations per h were also achieved. PMID:18924884

77 FR 66954 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Preliminary Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-08

... Steel Wire Rod From Mexico: Preliminary Results of Antidumping Duty Administrative Review; 2010-2011... conducting an administrative review of the antidumping duty order on carbon and certain alloy steel wire rod (wire rod) from Mexico. The period of review is October 1, 2010, through September 30, 2011, and the...

[The industrial environment in the electric-furnace steel smelting, converter and open-hearth furnace methods of manufacturing manganese-alloyed steels].

PubMed

Karnaukh, N G; Petrov, G A; Gapon, V A; Poslednichenko, I P; Shmidt, S E

1992-01-01

Inspection of the environment in manganese-alloyed steel production showed inadequate hygienic conditions of the technological processes employed. Air was more polluted by manganese oxides during the oxygen-converter process though their highest concentrations, 38 times exceeding the MAS, appeared during the casting of steel. An electric furnace coated by dust-noise-proof material and gas cleaning is preferable from a hygienic point of view. The influence of unfavourable microclimate, intensive infrared irradiation and loud noise on workers necessitates automation and mechanization of the process in order to improve the working conditions.

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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.

Low-cycle fatigue of Type 347 stainless steel and Hastelloy alloy X in hydrogen gas and in air at elevated temperatures

NASA Technical Reports Server (NTRS)

Jaske, C. E.; Rice, R. C.; Buchheit, R. D.; Roach, D. B.; Porfilio, T. L.

1976-01-01

An investigation was conducted to assess the low-cycle fatigue resistance of two alloys, Type 347 stainless steel and Hastelloy Alloy X, that were under consideration for use in nuclear-powered rocket vehicles. Constant-amplitude, strain-controlled fatigue tests were conducted under compressive strain cycling at a constant strain rate of 0.001/sec and at total axial strain ranges of 1.5, 3.0, and 5.0 %, in both laboratory-air and low-pressure hydrogen-gas environments at temperatures from 538 to 871 C. Specimens were obtained from three heats of Type 347 stainless steel bar and two heats of Hastelloy Alloy X. The tensile properties of each heat were determined at 21, 538, 649, and 760 C. The continuous cycling fatigue resistance was determined for each heat at temperatures of 538, 760, and 871 C. The Type 347 stainless steel exhibited equal or superior fatigue resistance to the Hastelloy Alloy X at all conditions of this study.

Structure and Properties of High-Temperature Multilayer Hybrid Material Based on Vanadium Alloy and Stainless Steel

NASA Astrophysics Data System (ADS)

Nechaykina, Tatyana A.; Nikulin, Sergey A.; Rozhnov, Andrey B.; Khatkevich, Vladimir M.; Rogachev, Stanislav O.

2017-03-01

The present work is devoted to the development of new structural composite material having the unique complex of properties for operating in ultrahard conditions that combine high temperatures, radiation, and aggressive environments. A new three-layer composite tube material based on vanadium alloy (V-4Ti-4Cr) protected by stainless steel (Fe-0.2C-13Cr) has been obtained by co-extrusion. Mechanism and kinetics of formation as well as structure, composition, and mechanical properties of "transition" area between vanadium alloy and stainless steel have been studied. The transition area (13- to 22- µm thick) of the diffusion interaction between vanadium alloy and steel was formed after co-extrusion. The microstructure in the transition area was rather complicated comprising different grain sizes in components, but having no defects or brittle phases. Tensile strength of the composite was an average 493 ± 22 MPa, and the elongation was 26 ± 3 pct. Annealing at 1073 K (800 °C) increased the thickness of transition area up to 1.2 times, homogenized microstructure, and slightly changed mechanical properties. Annealing at 1273 K (1000 °C) further increased the thickness of transition area and also lead to intensive grain growth in steel and sometimes to separation between composite components during tensile tests. Annealing at 1073 K (800 °C) is proposed as appropriate heat treatment after co-extrusion of composite providing balance between diffusion interaction thickness and microstructure and monolithic-like behavior of composite during tensile tests.

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

NASA Astrophysics Data System (ADS)

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.

78 FR 28190 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-14

... Steel Wire Rod From Mexico: Final Results of Antidumping Duty Administrative Review; 2010-2011 AGENCY... results of the administrative review of the antidumping duty order on carbon and certain alloy steel wire rod (wire rod) from Mexico. The period of review (POR) is October 1, 2010, through September 30, 2011...

Study of electroless Ni-W-P alloy coating on martensitic stainless steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nikitasari, Arini, E-mail: arini-nikitasari@yahoo.com; Mabruri, Efendi, E-mail: efendi-lipi@yahoo.com

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. Acidmore » 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).« less

A review of recent progress in coatings, surface modifications and alloy developments for solid oxide fuel cell ferritic stainless steel interconnects

NASA Astrophysics Data System (ADS)

Shaigan, Nima; Qu, Wei; Ivey, Douglas G.; Chen, Weixing

Ferritic stainless steels have become the standard material for solid oxide fuel cell (SOFC) interconnect applications. The use of commercially available ferritic stainless steels, not specifically designed for interconnect application, however, presents serious issues leading to premature degradation of the fuel cell stack, particularly on the cathode side. These problems include rapidly increasing contact resistance and volatilization of Cr from the oxide scales, resulting in cathode chromium poisoning and cell malfunction. To overcome these issues, a variety of conductive/protective coatings, surface treatments and modifications as well as alloy development have been suggested and studied over the past several years. This paper critically reviews the attempts performed thus far to mitigate the issues associated with the use of ferritic stainless steels on the cathode side. Different approaches are categorized and summarized and examples for each case are provided. Finally, directions and recommendations for the future studies are presented.

Deformation Characteristics and Recrystallization Response of a 9310 Steel Alloy

NASA Astrophysics Data System (ADS)

Snyder, David; Chen, Edward Y.; Chen, Charlie C.; Tin, Sammy

2013-01-01

The flow behavior and recrystallization response of a 9310 steel alloy deformed in the ferrite temperature range were studied in this work. Samples were compressed under various conditions of strain (0.6, 0.8 and multi-axial), strain rate (10-4 seconds-1 to 10-1 seconds-1) and temperature [811 K to 1033 K (538 °C to 760 °C)] using a Gleeble thermo-mechanical simulator. Deformation was characterized by both qualitative and quantitative means, using standard microscopy, electron backscatter diffraction (EBSD) analysis and flow stress modeling. The results indicate that deformation is primarily accommodated through dynamic recovery in sub-grain formation. EBSD analysis shows a continuous increase in sub-grain boundary misorientation with increasing strain, ultimately producing recrystallized grains from the sub-grains at high strains. This suggests that a sub-grain rotation recrystallization mechanism predominates in this temperature range. Analyses of the results reveal a decreasing mean dynamically recrystallized grain size with increasing Zener-Hollomon parameter, and an increasing recrystallized fraction with increasing strain.

Laser cladding of stainless steel with a copper-silver alloy to generate surfaces of high antimicrobial activity

NASA Astrophysics Data System (ADS)

Hans, Michael; Támara, Juan Carlos; Mathews, Salima; Bax, Benjamin; Hegetschweiler, Andreas; Kautenburger, Ralf; Solioz, Marc; Mücklich, Frank

2014-11-01

Copper and silver are used as antimicrobial agents in the healthcare sector in an effort to curb infections caused by bacteria resistant to multiple antibiotics. While the bactericidal potential of copper and silver alone are well documented, not much is known about the antimicrobial properties of copper-silver alloys. This study focuses on the antibacterial activity and material aspects of a copper-silver model alloy with 10 wt% Ag. The alloy was generated as a coating with controlled intermixing of copper and silver on stainless steel by a laser cladding process. The microstructure of the clad was found to be two-phased and in thermal equilibrium with minor Cu2O inclusions. Ion release and killing of Escherichia coli under wet conditions were assessed with the alloy, pure silver, pure copper and stainless steel. It was found that the copper-silver alloy, compared to the pure elements, exhibited enhanced killing of E. coli, which correlated with an up to 28-fold increased release of copper ions. The results show that laser cladding with copper and silver allows the generation of surfaces with enhanced antimicrobial properties. The process is particularly attractive since it can be applied to existing surfaces.

High Power Laser Welding. [of stainless steel and titanium alloy structures

NASA Technical Reports Server (NTRS)

Banas, C. M.

1972-01-01

A review of recent developments in high power, carbon dixoide laser welding is presented. Deep penetration welding in stainless steel to 0.5-in. thick, high speed welding in thin gage rimmed steel and gas shielded welding in Ti-6Al-4V alloy are described. The effects of laser power, power density, focusing optics, gas-shielding techniques, material properties and weld speed on weld quality and penetration are discussed. It is shown that laser welding performance in thin materials is comparable to that of electron beams. It is further shown that high quality welds, as evidenced by NDT, mechanical and metal-lographic tests, can be achieved. The potential of the laser for industrial welding applications is indicated.

49 CFR 178.512 - Standards for steel, aluminum or other metal boxes.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Standards for steel, aluminum or other metal boxes...) SPECIFICATIONS FOR PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.512 Standards for steel, aluminum or other metal boxes. (a) The following are identification codes for steel, aluminum, or other...

49 CFR 178.512 - Standards for steel, aluminum or other metal boxes.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for steel, aluminum or other metal boxes...) SPECIFICATIONS FOR PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.512 Standards for steel, aluminum or other metal boxes. (a) The following are identification codes for steel, aluminum, or other...

Vacuum Brazing TC4 Titanium Alloy to 304 Stainless Steel with Cu-Ti-Ni-Zr-V Amorphous Alloy Foil

NASA Astrophysics Data System (ADS)

Dong, Honggang; Yang, Zhonglin; Wang, Zengrui; Deng, Dewei; Dong, Chuang

2014-10-01

Dissimilar metal vacuum brazing between TC4 titanium alloy and 304 stainless steel was conducted with newly designed Cu-Ti-Ni-Zr-V amorphous alloy foils as filler metals. Solid joints were obtained due to excellent compatibility between the filler metal and stainless steel substrate. Partial dissolution of stainless steel substrate occurred during brazing. The shear strength of the joint brazed with Cu43.75Ti37.5Ni6.25Zr6.25V6.25 foil was 105 MPa and that with Cu37.5Ti25Ni12.5Zr12.5V12.5 was 116 MPa. All the joints fractured through the gray layer in the brazed seam, revealing brittle fracture features. Cr4Ti, Cu0.8FeTi, Fe8TiZr3 and Al2NiTi3C compounds were found in the fractured joint brazed with Cu43.75Ti37.5Ni6.25Zr6.25V6.25 foil, and Fe2Ti, TiCu, Fe8TiZr3 and NiTi0.8Zr0.3 compounds were detected in the joint brazed with Cu37.5Ti25Ni12.5Zr12.5V12.5 foil. The existence of Cr-Ti, Fe-Ti, Cu-Fe-Ti, and Fe-Ti-V intermetallic compounds in the brazed seam caused fracture of the resultant joints.

Microstructural-Scale Model for Surfaces Spreading of Intergranular Corrosion in Sensitized Stainless Steels and Aluminum-Magnesium (AA5XXX) Alloys

NASA Astrophysics Data System (ADS)

Jain, Swati

Components from AA5XXX (Al-Mg alloys with more than 3 wt% Mg) alloys are X attractive due to availability of low cost, high strength to weight ratio and good weldability. Therefore, these alloys have potential applications in Naval ships. However, these alloys become susceptible to IGC (intergranular corrosion) due to beta-phase precipitation due to improper heat treatment or inadvertent thermal exposure. Stainless steels may also become susceptible due to carbide precipitation and chromium depletion on grain boundaries. IGC susceptibility depends on the interplay between the metallurgical conditions, electrochemical conditions, and chemical conditions. Specific combinations cause IGC while others do not. The objective of this study is to investigate the conditions which bring about surface spreading of IGC in these alloy classes. To accomplish this goal, a microstructure scale model was developed with experimental inputs to understand the 2-D IGC spreading in stainless steels and AA5XXX alloys. The conditions strongly affecting IGC spreading were elucidated. Upon natural and artificial aging, the stainless steels become susceptible to intergranular corrosion because of chromium depletion in the grain boundaries. After aging Al-Mg (AA5XXX) alloys show susceptibility due to the precipitation of the beta-phase (Al3Mg7) in the grain boundaries. Chromium depleted grain boundaries in stainless steels are anodically more active as compared to the interior of the grains. (3-phase rich grain boundaries have lower OCP (open circuit potential) and pitting potentials as compared to the Al-Mg solid solutions. A new approach to modeling the IGC surface spreading in polycrystalline materials that is presented. This model is the first to couple several factors into one granular scale model that illustrates the way in which they interact and IGC occurs. It sheds new information on conditions which cause IGC spreading in two alloy classes and describes a new theory for the critical

Microstructural development at weld interface between Zr-based glassy alloy and stainless steel by resistance microwelding

NASA Astrophysics Data System (ADS)

Fukumoto, S.; Minami, M.; Soeda, A.; Matsushima, M.; Takahashi, M.; Yokoyama, Y.; Fujimoto, K.

2012-08-01

Zr-based bulk metallic glasses are expected to be welded to conventional structural alloys. Dissimilar welding of metallic glasses to stainless steel was carried out by resistance microwelding. The metallurgical analysis of the weld interface revealed the welding mechanism. A thin reaction layer was formed between the two liquid materials. The melting of stainless steel should be limited to obtain sound joints.

49 CFR 178.511 - Standards for aluminum and steel jerricans.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for aluminum and steel jerricans. 178... steel jerricans. (a) The following are identification codes for aluminum and steel jerricans: (1) 3A1 for a non-removable head steel jerrican; (2) 3A2 for a removable head steel jerrican; (3) 3B1 for a...

49 CFR 178.511 - Standards for aluminum and steel jerricans.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for aluminum and steel jerricans. 178... steel jerricans. (a) The following are identification codes for aluminum and steel jerricans: (1) 3A1 for a non-removable head steel jerrican; (2) 3A2 for a removable head steel jerrican; (3) 3B1 for a...

49 CFR 178.511 - Standards for aluminum and steel jerricans.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for aluminum and steel jerricans. 178... steel jerricans. (a) The following are identification codes for aluminum and steel jerricans: (1) 3A1 for a non-removable head steel jerrican; (2) 3A2 for a removable head steel jerrican; (3) 3B1 for a...

49 CFR 178.511 - Standards for aluminum and steel jerricans.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Standards for aluminum and steel jerricans. 178... steel jerricans. (a) The following are identification codes for aluminum and steel jerricans: (1) 3A1 for a non-removable head steel jerrican; (2) 3A2 for a removable head steel jerrican; (3) 3B1 for a...

49 CFR 178.511 - Standards for aluminum and steel jerricans.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for aluminum and steel jerricans. 178... steel jerricans. (a) The following are identification codes for aluminum and steel jerricans: (1) 3A1 for a non-removable head steel jerrican; (2) 3A2 for a removable head steel jerrican; (3) 3B1 for a...

Phase constitution characteristics of the Fe-Al alloy layer in the HAZ of calorized steel pipe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Yajiang; Zou Zengda; Wei Xing

1997-09-01

Mechanical properties of the welding region and phase constitution characteristics in the iron-aluminum (Fe-Al) alloy layer of calorized steel pipes were researched by means of metallography, which included the use of scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron probe microanalysis (EPMA) and an X-ray diffractometer. Experimental results indicated that the Fe-Al alloy layer of calorized steel pipe was mainly composed of an FeAl phase, an Fe{sub 3}Al phase and an {alpha}-Fe(Al) solid solution, and the microhardness in the Fe-Al coating was 600--310 HM from the surface layer to the inside. There were no higher aluminum content phases, suchmore » as brittle FeAl{sub 2}, Fe{sub 2}Al{sub 5} and FeAl{sub 3}. By controlling the aluminizing process parameters, the ability to bear deformation and weld-ability of the calorized steel pipe were remarkably improved.« less

Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

DOEpatents

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.

TAZ-8A Alloy Increases The Thermal Endurance Of Steel

NASA Technical Reports Server (NTRS)

Waters, William J.

1990-01-01

TAZ-8A exhibits high strength at temperatures as high as 1,400 degrees F (760 degrees C) and resistance to oxidation; also exhibits excellent cyclic shock resistance between 600 and 2,000 degrees F (316 and 1,093 degrees C) and superplasticity at 1,800 degrees F (982 degrees C). Converts into fine powder and then flame-, plasma-, arc-, or wire-sprayed onto inexpensive steel substrate. Surface treatment with this alloy prolongs service life and reduces costs.

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

46 CFR 56.60-5 - Steel (High temperature applications).

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2... steel, plain nickel-alloy steel, carbon-manganese-alloy steel, manganese-vanadium-alloy steel, and...

Errors in measurements by ultrasonic thickness gauges caused by the variation in ultrasonic velocity in constructional steels and metal alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalinin, V.A.; Tarasenko, V.L.; Tselser, L.B.

1988-09-01

Numerical values of the variation in ultrasonic velocity in constructional metal alloys and the measurement errors related to them are systematized. The systematization is based on the measurement results of the group ultrasonic velocity made in the All-Union Scientific-Research Institute for Nondestructive Testing in 1983-1984 and also on the measurement results of the group velocity made by various authors. The variations in ultrasonic velocity were systematized for carbon, low-alloy, and medium-alloy constructional steels; high-alloy iron base alloys; nickel-base heat-resistant alloys; wrought aluminum constructional alloys; titanium alloys; and cast irons and copper alloys.

Methods of forming steel

DOEpatents

Branagan, Daniel J.; Burch, Joseph V.

2001-01-01

In one aspect, the invention encompasses a method of forming a steel. A metallic glass is formed and at least a portion of the glass is converted to a crystalline steel material having a nanocrystalline scale grain size. In another aspect, the invention encompasses another method of forming a steel. A molten alloy is formed and cooled the alloy at a rate which forms a metallic glass. The metallic glass is devitrified to convert the glass to a crystalline steel material having a nanocrystalline scale grain size. In yet another aspect, the invention encompasses another method of forming a steel. A first metallic glass steel substrate is provided, and a molten alloy is formed over the first metallic glass steel substrate to heat and devitrify at least some of the underlying metallic glass of the substrate.

Corrosion Fatigue Characteristics of 12Cr Alloy Steel in Na2SO4 Solution

NASA Astrophysics Data System (ADS)

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.

Role of alloying elements in adhesive transfer and friction of copper-base alloys

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1978-01-01

Sliding friction experiments were conducted in a vacuum with binary-copper alloy riders sliding against a conventional bearing-steel surface with normal residual oxides present. The binary alloys contained 1 atomic percent of various alloying elements. Auger spectroscopy analysis was used to monitor the adhesive transfer of the copper alloys to the bearing-steel surface. A relation was found to exist between adhesive transfer and the reaction potential and free energy of formation of the alloying element in the copper. The more chemically active the element and the more stable its oxide, the greater was the adhesive transfer and wear of the copper alloy. Transfer occurred in all the alloys except copper-gold after relatively few (25) passes across the steel surface.

Effect of Al and Mg Contents on Wettability and Reactivity of Molten Zn-Al-Mg Alloys on Steel Sheets Covered with MnO and SiO2 Layers

NASA Astrophysics Data System (ADS)

Huh, Joo-Youl; Hwang, Min-Je; Shim, Seung-Woo; Kim, Tae-Chul; Kim, Jong-Sang

2018-05-01

The reactive wetting behaviors of molten Zn-Al-Mg alloys on MnO- and amorphous (a-) SiO2-covered steel sheets were investigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests were carried out at 460 °C and the variation in the contact angles (θc) of alloys containing 0.2-2.5 wt% Al and 0-3.0 wt% Mg was monitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the a-SiO2-covered steel exhibited nonreactive, nonwetting (θc > 90°) behavior. The MnO layer was rapidly removed by Al and Mg contained in the alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreased upon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the a-SiO2 layer were found to be sluggish, the wettability of Zn-Al-Mg alloys on the a-SiO2 layer improved upon increasing the Al and Mg contents. These results suggest that the wetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and SiO2, with Zn-Al-Mg alloys could be most effectively improved by increasing the Mg content of the alloys.

A study of microstructure, quasi-static response, fatigue, deformation and fracture behavior of high strength alloy steels

NASA Astrophysics Data System (ADS)

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.

Stress corrosion cracking behavior of irradiated model austenitic stainless steel alloys.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, H. M.; Karlsen, T. M.; Ruther, W. E.

Slow-strain-rate tensile tests (SSRTs) and posttest fractographic analyses by scanning electron microscopy were conducted on 16 austenitic stainless steel (SS) alloys that were irradiated at 289 C in He. After irradiation to {approx}0.3 x 10{sup 21} n{center_dot}cm{sup {minus}2} and {approx}0.9 x 10{sup 21} n{center_dot}cm{sup {minus}2} (E >1 MeV), significant heat-to-heat variations in the degree of intergranular and transgranular stress corrosion cracking (IGSCC and TGSCC) were observed. Following irradiation to a fluence of {approx}0.3 x 10{sup 21} n{center_dot}cm{sup {minus}2}, a high-purity laboratory heat of Type 316L SS (Si {approx} 0.024 wt%) exhibited the highest susceptibility to IGSCC. The other 15 alloysmore » exhibited negligible susceptibility to IGSCC at this low fluence. The percentage of TGSCC on the fracture surfaces of SSRT specimens of the 16 alloys at {approx}0.3 x 10{sup 21} n{center_dot}cm{sup {minus}2} (E > 1 MeV) could be correlated well with N and Si concentrations; all alloys that contained <0.01 wt.% N and <1.0 wt. % Si were susceptible, whereas all alloys that contained >0.01 wt.% N or >1.0 wt.% Si were relatively resistant. High concentrations of Cr were beneficial. Alloys that contain <15.5 wt.% Cr exhibited greater percentages of TGSCC and IGSCC than those alloys with {approx}18 wt.% Cr, whereas an alloy that contains >21 wt.% Cr exhibited less susceptibility than the lower-Cr alloys under similar conditions.« less

Effects of Zr Addition on Strengthening Mechanisms of Al-Alloyed High-Cr ODS Steels.

PubMed

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.

Effects of Zr Addition on Strengthening Mechanisms of Al-Alloyed High-Cr ODS Steels

PubMed Central

Ren, Jian; Yu, Liming; Liu, Yongchang; Liu, Chenxi; Li, Huijun; Wu, Jiefeng

2018-01-01

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. PMID:29329260

Low temperature mechanical properties, fractographic and metallographic evaluation of several alloy steels

NASA Technical Reports Server (NTRS)

Montano, J. W.

1973-01-01

The mechanical properties are presented of alloy steels, 4130, 4140, 4340, 6150, and 8740. Test specimens were manufactured from approximately 1.00 inch (2.54 cm) diameter bar stock which had been heat treated to two different hardness levels. The following mechanical tests were performed at temperatures of 80 F (+26.7 C), 0 F (-17.8 C), -100 F (-73 C), and -200 F (-129 C): (1) tensile test (Ultimate, yield, modulus, elongation, and reduction of area), (2) notched tensile test, (3) charpy V-notched impact test (impact energy), and (4) double shear strength test (ultimate and yield). The test data indicate excellent tensile strength, notched/unnotched tensile ratios, ductility, impact, and shear properties at all test temperatures, except at -200 F (-129 C) where the impact strength of the higher strength group of alloy steels, 4130 (Rc-37) and 4140 (Rc-44) decreased to approximately 9 ft. lbs. (12 joules) and 6 ft. lbs. (8 joules), respectively. Chemical, metallographic, and fractographic analyses were also performed to evaluate microstructure, microhardness and the effect of decrease in temperature on the ductile to brittle failure transition.

Effects of gaseous nitriding AISI4140 alloy steel on corrosion and hardness properties

NASA Astrophysics Data System (ADS)

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.

Surface modification of steels and magnesium alloy by high current pulsed electron beam

NASA Astrophysics Data System (ADS)

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.

Influence of laser radiation on structure and properties of steels and alloys

NASA Astrophysics Data System (ADS)

Tarasova, T.; Popova, E.

2013-03-01

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.

A comparative assessment of the fracture toughness behavior of ferritic-martensitic steels and nanostructured ferritic alloys

NASA Astrophysics Data System (ADS)

Byun, Thak Sang; Hoelzer, David T.; Kim, Jeoung Han; Maloy, Stuart A.

2017-02-01

The Fe-Cr alloys with ultrafine microstructures are primary candidate materials for advanced nuclear reactor components because of their excellent high temperature strength and high resistance to radiation-induced damage such as embrittlement and swelling. Mainly two types of Fe-Cr alloys have been developed for the high temperature reactor applications: the quenched and tempered ferritic-martensitic (FM) steels hardened primarily by ultrafine laths and carbonitrides and the powder metallurgy-based nanostructured ferritic alloys (NFAs) by nanograin structure and nanoclusters. This study aims at elucidating the differences and similarities in the temperature and strength dependences of fracture toughness in the Fe-Cr alloys to provide a comparative assessment of their high-temperature structural performance. The KJQ versus yield stress plots confirmed that the fracture toughness was inversely proportional to yield strength. It was found, however, that the toughness data for some NFAs were outside the band of the integrated dataset at given strength level, which indicates either a significant improvement or deterioration in mechanical properties due to fundamental changes in deformation and fracture mechanisms. When compared to the behavior of NFAs, the FM steels have shown much less strength dependence and formed narrow fracture toughness data bands at a significantly lower strength region. It appeared that at high temperatures ≥600 °C the NFAs cannot retain the nanostructure advantage of high strength and high toughness either by high-temperature embrittlement or by excessive loss of strength. Irradiation studies have revealed, however, that the NFAs have much stronger radiation resistance than tempered martensitic steels, such as lower radiation-induced swelling, finer helium bubble formation, lower irradiation creep rate and reduced low temperature embrittlement.

76 FR 33218 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Initiation of Anti-Circumvention Inquiry of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-08

... Steel Wire Rod From Mexico: Initiation of Anti-Circumvention Inquiry of Antidumping Duty Order AGENCY..., under 19 CFR 351.225(k)(2) to determine whether wire rod with an actual diameter between 4.75 and 5.00 millimeters (mm) is within the scope of the antidumping (AD) order on carbon and certain alloy steel wire rod...

Study made of corrosion resistance of stainless steel and nickel alloys in nuclear reactor superheaters

NASA Technical Reports Server (NTRS)

Greenberg, S.; Hart, R. K.; Lee, R. H.; Ruther, W. E.; Schlueter, R. R.

1967-01-01

Experiments performed under conditions found in nuclear reactor superheaters determine the corrosion rate of stainless steel and nickel alloys used in them. Electropolishing was the primary surface treatment before the corrosion test. Corrosion is determined by weight loss of specimens after defilming.

Larson-Miller Constant of Heat-Resistant Steel

NASA Astrophysics Data System (ADS)

Tamura, Manabu; Abe, Fujio; Shiba, Kiyoyuki; Sakasegawa, Hideo; Tanigawa, Hiroyasu

2013-06-01

Long-term rupture data for 79 types of heat-resistant steels including carbon steel, low-alloy steel, high-alloy steel, austenitic stainless steel, and superalloy were analyzed, and a constant for the Larson-Miller (LM) parameter was obtained in the current study for each material. The calculated LM constant, C, is approximately 20 for heat-resistant steels and alloys except for high-alloy martensitic steels with high creep resistance, for which C ≈ 30 . The apparent activation energy was also calculated, and the LM constant was found to be proportional to the apparent activation energy with a high correlation coefficient, which suggests that the LM constant is a material constant possessing intrinsic physical meaning. The contribution of the entropy change to the LM constant is not small, especially for several martensitic steels with large values of C. Deformation of such martensitic steels should accompany a large entropy change of 10 times the gas constant at least, besides the entropy change due to self-diffusion.

77 FR 13545 - Carbon and Certain Alloy Steel Wire Rod From Mexico: Notice of Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-07

... Steel Wire Rod From Mexico: Notice of Final Results of Antidumping Duty Administrative Review AGENCY... results of the administrative review of the antidumping duty order on carbon and certain alloy steel wire rod (wire rod) from Mexico.\\1\\ This review covers imports of wire rod from ArcelorMittal Las Truchas...

Proving the viability of manufacturing of multi-layer steel/vanadium alloy/steel composite tubes by numerical simulations and experiment

NASA Astrophysics Data System (ADS)

Nechaykina, T.; Nikulin, S.; Rozhnov, A.; Molotnikov, A.; Zavodchikov, S.; Estrin, Y.

2018-05-01

Vanadium alloys are promising structural materials for fuel cladding tubes for fast-neutron reactors. However, high solubility of oxygen and nitrogen in vanadium alloys at operating temperatures of 700 °C limits their application. In this work, we present a novel composite structure consisting of vanadium alloy V-4Ti-4Cr (provides high long-term strength of the material) and stainless steel Fe-0.2C-13Cr (as a corrosion resistant protective layer). It is produced by co-extrusion of these materials forming a three-layered tube. Finite element simulations were utilised to explore the influence of the various co-extrusion parameters on manufacturability of multi-layered tubes. Experimental verification of the numerical modelling was performed using co-extrusion with the process parameters suggested by the numerical simulations. Scanning electron microscopy and microhardness measurements revealed a defect-free diffusion layer at the interfaces between both materials indicating a good quality bonding for these co-extrusion conditions.

Surface laser alloying of 17-4PH stainless steel steam turbine blades

NASA Astrophysics Data System (ADS)

Yao, Jianhua; Wang, Liang; Zhang, Qunli; Kong, Fanzhi; Lou, Chenghua; Chen, Zhijun

2008-09-01

As a known high-quality precipitation hardening stainless steel with high strength, high antifatigue, excellent corrosion resistance and good weldability, 17-4PH has been widely used to produce steam turbine blades. However, under the impact of high-speed steam and water droplets, the blades are prone to cavitation, which could lead to lower efficiency, shorter life time, and even accidents. In this article, the 17-4PH blade's surface was alloyed using a high power CO 2 laser. The microstructure and microhardness of hardened 17-4PH were tested by scanning electronic microscope (SEM), X-ray diffraction (XRD), energy disperse spectroscopy (EDS) and a microhardness tester. After laser alloying, the surface layer was denser and the grain refined, while the microhardness of the surface (average 610HV 0.2) was about one times higher than that of the substrate material (330HV 0.2). The friction coefficient of the laser-alloyed 17-4PH layer was much lower than that of the substrate.

Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review

NASA Astrophysics Data System (ADS)

Mu, Wangzhong; Jönsson, Pär Göran; Nakajima, Keiji

2017-04-01

Intragranular ferrite (IGF), which nucleates from specific inclusion surfaces in low alloy steels, is the desired microstructure to improve mechanical properties of steel such as the toughness. This microstructure is especially important in the coarse grain heat affected zone (CGHAZ) of weldments. The latest review paper focusing on the role of non-metallic inclusions in the IGF formation in steels has been reported by Sarma et al. in 2009 (ISIJ int., 49(2009), 1063-1074). In recent years, large amount of papers have been presented to investigate different issues of this topic. This paper mainly highlights the frontiers of experimental and theoretical investigations on the effects of inclusion characteristics, such as the composition, size distribution and number density, on the IGF formation in low carbon low-alloyed steels, undertaken by the group of Applied Process Metallurgy, KTH Royal Institute of Technology. Related results reported in previous studies are also introduced. Also, plausible future work regarding various items of IGF formation is mentioned in each section. This work aims to give a better control of improving the steel quality during casting and in the heat affected zone (HAZ) of weldment, according to the concept of oxide metallurgy.

Effect of Elemental Sulfur and Sulfide on the Corrosion Behavior of Cr-Mo Low Alloy Steel for Tubing and Tubular Components in Oil and Gas Industry.

PubMed

Khaksar, Ladan; Shirokoff, John

2017-04-20

The chemical degradation of alloy components in sulfur-containing environments is a major concern in oil and gas production. This paper discusses the effect of elemental sulfur and its simplest anion, sulfide, on the corrosion of Cr-Mo alloy steel at pH 2 and 5 during 10, 20 and 30 h immersion in two different solutions. 4130 Cr-Mo alloy steel is widely used as tubing and tubular components in sour services. According to the previous research in aqueous conditions, contact of solid sulfur with alloy steel can initiate catastrophic corrosion problems. The corrosion behavior was monitored by the potentiodynamic polarization technique during the experiments. Energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) have been applied to characterize the corrosion product layers after each experiment. The results show that under the same experimental conditions, the corrosion resistance of Cr-Mo alloy in the presence of elemental sulfur is significantly lower than its resistance in the presence of sulfide ions.

78 FR 60850 - Carbon and Certain Alloy Steel Wire Rod From Brazil: Final Results of the Expedited Second Sunset...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-02

... Steel Wire Rod From Brazil: Final Results of the Expedited Second Sunset Review of the Countervailing... of the countervailing duty (CVD) order on carbon and certain alloy steel wire rod (wire rod) from...: Background On June 3, 2013, the Department initiated the second sunset review of the CVD order \\1\\ on wire...

Fracture Characteristics of Two High-Strength, Low-Alloy and Two Stainless Steels

DTIC Science & Technology

1977-01-01

conditions. The effects of hydrogen. and temper. embrittlement on the materials’ behavior when fractured under tensile and fatigue fonditions were... effects of hydrogen- and tomper-embrittlement have a bet, crystal structure, this plane has the type on the materials’ behavior when fractured under...A. Troiano, "The Role of lydrogen and Other Intersiftials high-strength, low-alloy structural steels generally used in the Mechanical Behavior ot

The effect of aluminum alloying on strength properties and deformation mechanisms of the <123> Hadfield steel single crystals

NASA Astrophysics Data System (ADS)

Astafurova, E. G.; Tukeev, M. S.; Chumlyakov, Yu. I.

2007-10-01

The role of aluminum alloying on strength properties and deformation mechanisms (slip, twinning) of <123> single crystals of Hadfield steel under tensile loading at T = 300 K is demonstrated. It is found out that aluminum alloying suppresses twinning deformation in the <123> single crystals and, during slip, results in a dislocation structure change from a uniform dislocation distribution to a planar dislocation structure.

Creep, creep-rupture tests of Al-surface-alloyed T91 steel in liquid lead bismuth at 500 and 550 °C

NASA Astrophysics Data System (ADS)

Weisenburger, A.; Jianu, A.; An, W.; Fetzer, R.; Del Giacco, Mattia; Heinzel, A.; Müller, G.; Markov, V. G.; Kasthanov, A. D.

2012-12-01

Surface layers made of FeCrAl alloys on T91 steel have shown their capability as corrosion protection barriers in lead bismuth. Pulsed electron beam treatment improves the density and more over the adherence of such layers. After the treatment of previously deposited coatings a surface graded material is achieved with a metallic bonded interface. Creep-rupture tests of T91 in lead-alloy at 550 °C reveal significant reduced creep strength of non-modified T91 test specimens. Oxide scales protecting the steels from attacks of the liquid metal will crack at a certain strain leading to a direct contact between the steel and the liquid metal. The negative influence of the lead-alloy on the creep behavior of non-modified T91 is stress dependent, but below a threshold stress value of 120 MPa at 550 °C this influence becomes almost negligible. At 500 °C and stress values of 200 MPa and 220 MPa the creep rates are comparable between them and significantly lower than creep rates at 180 MPa of original T91 in air at 550 °C. No signs of LBE influence are detected. The surface modified specimens tested at high stress levels instead had creep-rupture times similar to T91 (original state) tested in air. The thin oxide layers formed on the surface modified steel samples are less susceptible to crack formation and therefore to lead-alloy enhanced creep.

Laser surface alloying of FeCoCrAlNi high-entropy alloy on 304 stainless steel to enhance corrosion and cavitation erosion resistance

NASA Astrophysics Data System (ADS)

Zhang, S.; Wu, C. L.; Zhang, C. H.; Guan, M.; Tan, J. Z.

2016-10-01

FeCoCrAlNi high-entropy alloy coating was synthesized with premixed high-purity Co, Cr, Al and Ni powders on 304 stainless steel by laser surface alloying, aiming at improving corrosion and cavitation erosion resistance. Phase constituents, microstructure and microhardness were investigated using XRD, SEM, and microhardness tester, respectively. The cavitation erosion and electrochemical corrosion behavior of FeCoCrAlNi coating in 3.5% NaCl solution were also evaluated using an ultrasonic vibrator and potentiodynamic polarization measurement. Experimental results showed that with appropriate laser processing parameters, FeCoCrAlNi coating with good metallurgical bonding to the substrate could be achieved. FeCoCrAlNi coating was composed of a single BCC solid solution. The formation of simple solid solutions in HEAs was the combined effect of mixing entropy (ΔSmix), mixing enthalpy (ΔHmix), atom-size difference (δ) and valence electron concentration (VEC), and the effect of ΔSmix was much larger than that of the other factors. The microhardness of the FeCoCrAlNi coating was ~3 times that of the 304 stainless steel. Both the corrosion and cavitation erosion resistance of the coating were improved. The cavitation erosion resistance for FeCoCrAlNi HEA coating was ~7.6 times that of 304 stainless steel. The corrosion resistance was also improved as reflected by a reduction in the current density of one order of magnitude as compared with 304 stainless steel.

The influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes in seawater

NASA Astrophysics Data System (ADS)

Bai, Qiang; Zou, Yan; Kong, Xiangfeng; Gao, Yang; Dong, Sheng; Zhang, Wei

2017-02-01

The high strength low-alloy steels are welded by underwater wet welding with stainless steel electrodes. The micro-structural and electrochemical corrosion study of base metal (BM), weld zone (WZ) and heat affected zone (HAZ) are carried out to understand the influence of the corrosion product layer generated on the high strength low-alloy steels welded by underwater wet welding with stainless steel electrodes, methods used including, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The results indicate that the WZ acts as a cathode and there is no corrosion product on it throughout the immersion period in seawater. The HAZ and BM acts as anodes. The corrosion rates of the HAZ and BM change with the immersion time increasing. In the initial immersion period, the HAZ has the highest corrosion rate because it has a coarse tempered martensite structure and the BM exhibites a microstructure with very fine grains of ferrite and pearlite. After a period of immersion, the BM has the highest corrosion rate. The reason is that the corrosion product layer on the HAZ is dense and has a better protective property while that on the BM is loose and can not inhibit the diffusion of oxygen.

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

Federal Register 2010, 2011, 2012, 2013, 2014

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...

Modeling of grain-oriented Si-steel and amorphous alloy iron core under ferroresonance using Jiles-Atherton hysteresis method

NASA Astrophysics Data System (ADS)

Sima, Wenxia; Zou, Mi; Yang, Ming; Yang, Qing; Peng, Daixiao

2018-05-01

Amorphous alloy is increasingly widely used in the iron core of power transformer due to its excellent low loss performance. However, its potential harm to the power system is not fully studied during the electromagnetic transients of the transformer. This study develops a simulation model to analyze the effect of transformer iron core materials on ferroresonance. The model is based on the transformer π equivalent circuit. The flux linkage-current (ψ-i) Jiles-Atherton reactor is developed in an Electromagnetic Transients Program-Alternative Transients Program and is used to represent the magnetizing branches of the transformer model. Two ferroresonance cases are studied to compare the performance of grain-oriented Si-steel and amorphous alloy cores. The ferroresonance overvoltage and overcurrent are discussed under different system parameters. Results show that amorphous alloy transformer generates higher voltage and current than those of grain-oriented Si-steel transformer and significantly harms the power system safety.

A comparative assessment of the fracture toughness behavior of ferritic-martensitic steels and nanostructured ferritic alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byun, Thak Sang; Hoelzer, David T.; Kim, Jeoung Han

The Fe-Cr alloys with ultrafine microstructures are primary candidate materials for advanced nuclear reactor components because of their excellent high temperature strength and high resistance to radiation-induced damage such as embrittlement and swelling. Mainly two types of Fe-Cr alloys have been developed for the high temperature reactor applications: the quenched and tempered ferritic-martensitic (FM) steels hardened primarily by ultrafine laths and carbonitrides and the powder metallurgy-based nanostructured ferritic alloys (NFAs) by nanograin structure and nanoclusters. This paper aims at elucidating the differences and similarities in the temperature and strength dependences of fracture toughness in the Fe-Cr alloys to provide amore » comparative assessment of their high-temperature structural performance. The K JQ versus yield stress plots confirmed that the fracture toughness was inversely proportional to yield strength. It was found, however, that the toughness data for some NFAs were outside the band of the integrated dataset at given strength level, which indicates either a significant improvement or deterioration in mechanical properties due to fundamental changes in deformation and fracture mechanisms. When compared to the behavior of NFAs, the FM steels have shown much less strength dependence and formed narrow fracture toughness data bands at a significantly lower strength region. It appeared that at high temperatures ≥600 °C the NFAs cannot retain the nanostructure advantage of high strength and high toughness either by high-temperature embrittlement or by excessive loss of strength. Finally, irradiation studies have revealed, however, that the NFAs have much stronger radiation resistance than tempered martensitic steels, such as lower radiation-induced swelling, finer helium bubble formation, lower irradiation creep rate and reduced low temperature embrittlement.« less

A comparative assessment of the fracture toughness behavior of ferritic-martensitic steels and nanostructured ferritic alloys

DOE PAGES

Byun, Thak Sang; Hoelzer, David T.; Kim, Jeoung Han; ...

2016-12-07

The Fe-Cr alloys with ultrafine microstructures are primary candidate materials for advanced nuclear reactor components because of their excellent high temperature strength and high resistance to radiation-induced damage such as embrittlement and swelling. Mainly two types of Fe-Cr alloys have been developed for the high temperature reactor applications: the quenched and tempered ferritic-martensitic (FM) steels hardened primarily by ultrafine laths and carbonitrides and the powder metallurgy-based nanostructured ferritic alloys (NFAs) by nanograin structure and nanoclusters. This paper aims at elucidating the differences and similarities in the temperature and strength dependences of fracture toughness in the Fe-Cr alloys to provide amore » comparative assessment of their high-temperature structural performance. The K JQ versus yield stress plots confirmed that the fracture toughness was inversely proportional to yield strength. It was found, however, that the toughness data for some NFAs were outside the band of the integrated dataset at given strength level, which indicates either a significant improvement or deterioration in mechanical properties due to fundamental changes in deformation and fracture mechanisms. When compared to the behavior of NFAs, the FM steels have shown much less strength dependence and formed narrow fracture toughness data bands at a significantly lower strength region. It appeared that at high temperatures ≥600 °C the NFAs cannot retain the nanostructure advantage of high strength and high toughness either by high-temperature embrittlement or by excessive loss of strength. Finally, irradiation studies have revealed, however, that the NFAs have much stronger radiation resistance than tempered martensitic steels, such as lower radiation-induced swelling, finer helium bubble formation, lower irradiation creep rate and reduced low temperature embrittlement.« less

Precipitation of Second Phases in High-Interstitial-Alloyed Austenitic Steel

NASA Astrophysics Data System (ADS)

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.

75 FR 13729 - Circular Welded Non-Alloy Steel Pipe from the Republic of Korea: Extension of Time Limit for the...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-23

... Steel Pipe from the Republic of Korea: Extension of Time Limit for the Final Results and Rescission in Part of the Antidumping Duty Administrative Review AGENCY: Import Administration, International Trade... Welded Non-Alloy Steel Pipe from the Republic of Korea: Preliminary Results and Rescission in Part of the...

Microscopic Observations of Adiabatic Shear Bands in Three Different Steels

DTIC Science & Technology

1988-09-01

low thermal conductivity, and a high thermal softening rate. Examples include alloys of titanium. aluminum, copper , as well as steels [5-221... steels : 1 (1) an AISI 1018 cold rolled steel , (2) a high strength low alloy structural steel , and deformation in shear was impo.ed to produce shear bands...stecls: (1) an AISI 1018 cold rolled steel , (2) a high strength low alloy structural steel , and (3) an AISI 4340 VAR steel tempered

Patch test reactivity to a cobalt-chromium-molybdenum alloy and stainless steel in metal-allergic patients in correlation to the metal ion release.

PubMed

Summer, Burkhard; Fink, Ulrich; Zeller, Richard; Rueff, Franziska; Maier, Sonja; Roider, Gabriele; Thomas, Peter

2007-07-01

Nickel, chromium, and cobalt released from stainless steel and CoCrMo alloys have been postulated to trigger hypersensitivity reactions. The objective of this study was to assess the ion release from a CoCrMo alloy and stainless steel in vitro and the cutaneous reactivity to it by patch test. 52 metal-allergic patients and 48 non-allergic controls were patch tested to stainless steel and CoCrMo discs. In addition, using atomic absorption spectrometry, the release of nickel, cobalt, and chromium from both materials was assessed upon 2-day exposure to distilled water, artificial sweat (AS), and cell culture medium. There was low nickel ion release from stainless steel (0.3-0.46 microg/cm(2)/2 days) and CoCrMo discs (up to 0.33 microg/cm(2)/2 days) into the different elution media. Chromium release from the 2 materials was also very low (0.06-0.38 microg/cm(2)/2 days from stainless steel and 0.52-1.36 microg/cm(2)/2 days from CoCrMo alloy). In contrast, AS led to abundant cobalt release (maximally 18.94 microg/cm(2)/2 days) from the CoCrMo discs, with concomitant eczematous reaction upon patch testing: 0 of the 52 metal-allergic patients reacted to stainless steel discs and 5 of the 52 patients to CoCrMo discs (all 5 patients were cobalt allergic and 3 also nickel and chromium allergic). None of the controls reacted to the discs. Apart from nickel being a focus of allergological research, our results point to the possibly underestimated association of cobalt release and potential hyperreactivity to CoCrMo alloy.

Corrosion-induced release of the main alloying constituents of manganese-chromium stainless steels in different media.

PubMed

Herting, Gunilla; Wallinder, Inger Odnevall; Leygraf, Christofer

2008-09-01

The main focus of this paper is the assessment of release rates of chromium, nickel, iron and manganese from manganese-chromium stainless steel grades of low nickel content. The manganese content varied between 9.7 and 1.5 wt% and the corresponding nickel content between 1 and 5 wt%. All grades were exposed to artificial rain and two were immersed in a synthetic body fluid of similar pH but of different composition and exposure conditions. Surface compositional studies were performed using X-ray photoelectron spectroscopy (XPS) in parallel to correlate the metal release process with changes in surface oxide properties. All grades, independent of media, revealed a time-dependent metal release process with a preferential low release of iron and manganese compared to nickel and chromium while the chromium content of the surface oxide increased slightly. Manganese was detected in the surface oxide of all grades, except the grade of the lowest manganese bulk content. No nickel was observed in the outermost surface oxide. Stainless steel grades of the lowest chromium content (approximately 16 wt%) and highest manganese content (approximately 7-9 wt%), released the highest quantity of alloy constituents in total, and vice versa. No correlation was observed between the release rate of manganese and the alloy composition. Released main alloy constituents were neither proportional to the bulk alloy composition nor to the surface oxide composition.

Constitutive Modeling of High-Temperature Flow Behavior of an Nb Micro-alloyed Hot Stamping Steel

NASA Astrophysics Data System (ADS)

Zhang, Shiqi; Feng, Ding; Huang, Yunhua; Wei, Shizhong; Mohrbacher, Hardy; Zhang, Yue

2016-03-01

The thermal deformation behavior and constitutive models of an Nb micro-alloyed 22MnB5 steel were investigated by conducting isothermal uniaxial tensile tests at the temperature range of 873-1223 K with strain rates of 0.1-10 s-1. The results indicated that the investigated steel showed typical work hardening and dynamic recovery behavior during hot deformation, and the flow stress decreased with a decrease in strain rate and/or an increase in temperature. On the basis of the experimental data, the modified Johnson-Cook (modified JC), modified Norton-Hoff (modified NH), and Arrhenius-type (AT) constitutive models were established for the subject steel. However, the flow stress values predicted by these three models revealed some remarkable deviations from the experimental values for certain experimental conditions. Therefore, a new combined modified Norton-Hoff and Arrhenius-type constitutive model (combined modified NH-AT model), which accurately reflected both the work hardening and dynamic recovery behavior of the subject steel, was developed by introducing the modified parameter k ɛ. Furthermore, the accuracy of these constitutive models was assessed by the correlation coefficient, the average absolute relative error, and the root mean square error, which indicated that the flow stress values computed by the combined modified NH-AT model were highly consistent with the experimental values (R = 0.998, AARE = 1.63%, RMSE = 3.85 MPa). The result confirmed that the combined modified NH-AT model was suitable for the studied Nb micro-alloyed hot stamping steel. Additionally, the practicability of the new model was also verified using finite element simulations in ANSYS/LS-DYNA, and the results confirmed that the new model was practical and highly accurate.

Investigations on Laser Beam Welding of Different Dissimilar Joints of Steel and Aluminum Alloys for Automotive Lightweight Construction

NASA Astrophysics Data System (ADS)

Seffer, Oliver; Pfeifer, Ronny; Springer, André; Kaierle, Stefan

Due to the enormous potential of weight saving, and the consequential reduction of pollutant emissions, the use of hybrid components made of steel and aluminum alloys is increasing steadily, especially concerning automotive lightweight construction. However, thermal joining of steel and aluminum is still being researched, due to a limited solubility of the binary system of iron and aluminum causing the formation of hard and brittle intermetallic phases, which decrease the strength and the formability of the dissimilar seam. The presented results show the investigation of laser beam welding for joining different dissimilar hybrid components of the steel materials HX220LAD+Z100, 22MnB5+AS150 and 1.4301, as well as the aluminum alloy AA6016-T4 as a lap joint. Among other things, the influences of the energy per unit length, the material grade, the sheet thickness t, the weld type (lap weld, fillet weld) and the arrangement of the base materials in a lap joint (aluminum-sided irradiation, steel-sided irradiation) on the achievable strengths are analyzed. The characterization of the dissimilar joints includes tensile shear tests and metallographic analyses, depending on the energy per unit length.

Femtosecond laser-induced periodic surface structures on steel and titanium alloy for tribological applications

NASA Astrophysics Data System (ADS)

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.

Hydrogen adsorption and diffusion, and subcritical-crack growth in high strength steels and nickel base alloys

NASA Technical Reports Server (NTRS)

Wei, R. P.; Klier, K.; Simmons, G. W.; Chornet, E.

1973-01-01

Embrittlement, or the enhancement of crack growth by gaseous hydrogen in high strength alloys, is of primary interest in selecting alloys for various components in the space shuttle. Embrittlement is known to occur at hydrogen gas pressures ranging from fractions to several hundred atmospheres, and is most severe in the case of martensitic high strength steels. Kinetic information on subcritical crack growth in gaseous hydrogen is sparse at this time. Corroborative information on hydrogen adsorption and diffusion is inadequate to permit a clear determination of the rate controlling process and possible mechanism in hydrogen enhanced crack growth, and for estimating behavior over a range of temperatures and pressures. Therefore, coordinated studies of the kinetics of crack growth, and adsorption and diffusion of hydrogen, using identical materials, have been initiated. Comparable conditions of temperature and pressure will be used in the chemical and mechanical experiments. Inconel 718 alloy and 18Ni(200) maraging steel have been selected for these studies. Results from these studies are expected to provide not only a better understanding of the gaseous hydrogen embrittlement phenomenon itself, but also fundamental information on hydrogen adsorption and diffusion, and crack growth information that can be used directly for design.

Creep and microstructural processes in a low-alloy 2.25%Cr1.6%W steel (ASTM Grade 23)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kucharova, K.; Sklenicka, V., E-mail: sklen@ipm.cz; CEITEC — IPM, Institute of Physics of Materials, Academy of Sciences of the Czech Republic, CZ-616 62 Brno

2015-11-15

A low-alloy 2.25%Cr1%Mo steel (ASTM Grade 22) has been greatly improved by the substitution of almost all of the 1%Mo by 1.6%W. The improved material has been standardized as P/T23 steel (Fe–2.25Cr–1.6W–0.25V–0.05Nb–0.07C). The present investigation was conducted on T23 steel in an effort to obtain a more complete description and understanding of the role of the microstructural evolution and deformation processes in high-temperature creep. Constant load tensile creep tests were carried out in an argon atmosphere in the temperature range 500–650 °C at stresses ranging from 50 to 400 MPa. It was found that the diffusion in the matrix latticemore » is the creep-rate controlling process. The results of an extensive transmission electron microscopy (TEM) analysis programme to investigate microstructure evolution as a function of temperature are described and compared with the thermodynamic calculations using the software package Thermo-Calc. The significant creep-strength drop of T23 steel after long-term creep exposures can be explained by the decrease in dislocation hardening, precipitation hardening and solid solution hardening due to the instability of the microstructure at high temperature. - Highlights: • The constant load creep tests of T23 steel were carried out at 500–650 °C. • The stress exponents of the creep rate correspond to power law (dislocation) creep. • Diffusion in the matrix lattice is the creep-rate controlling process. • The microstructure instability is the main creep degradation process in T23 steel.« less

Investigation of Electrodeposited Alloys and Pure Metals as Substitutes for Zinc and Cadmium for Protective Finishes for Steel Parts of Aircraft

DTIC Science & Technology

1949-09-01

ON LOAN FROM 7k a. **+dU fefeÄtüiÄ: .<*-#=« Investigation of Electrodeposited Alloys and Pure Metals as Substitutes for Zinc and Cadmium for...graphs Eight alloys, selected as being superior to pure zinc or cadmium for protecting steel, were evaluated on the basis of static and dynamic... zinc -silver alloy of 25% silver. A tabulated summary of the testing program on all cast and electrodeposited alloys tested is included. * and

Crack Resistance of Welded Joints of Pipe Steels of Strength Class K60 of Different Alloying Systems

NASA Astrophysics Data System (ADS)

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.

Influence of Minor Alloying Elements on Selective Oxidation and Reactive Wetting of CMnSi TRIP Steel during Hot Dip Galvanizing

NASA Astrophysics Data System (ADS)

Cho, Lawrence; Kim, Myung Soo; Kim, Young Ha; De Cooman, Bruno C.

2014-09-01

The influence of the addition of minor alloying elements on the selective oxidation and the reactive wetting of CMnSi transformation-induced plasticity (TRIP) steels was studied by means of galvanizing simulator tests. Five TRIP steels containing small alloying additions of Cr, Ni, Ti, Cu, and Sn were investigated. After intercritical annealing (IA) at 1093 K (820 °C) in a N2 + 5 pct H2 gas atmosphere with a dew point of 213 K (-60 °C), two types of oxides were formed on the strip surface: Mn-rich xMnO·SiO2 ( x > 1.5) and Si-rich xMnO·SiO2 ( x < 0.3) oxides. The addition of the minor alloying elements changed the morphology of the Si-rich oxides from a continuous film to discrete islands and this improved the wettability by molten Zn. The improved wetting effect of the minor alloying elements was attributed to an increased area fraction of the surface where the oxides were thinner, enabling a direct unhindered reaction between Fe and the Al in the liquid Zn and the formation of the inhibition layer during the hot dip galvanizing. The addition of a small amount of Sn is shown to significantly decrease the density of Zn-coating defects on CMnSi TRIP steels.

Oxidation behavior and area specific resistance of La, Cu and B alloyed Fe-22Cr ferritic steels for solid oxide fuel cell interconnects

NASA Astrophysics Data System (ADS)

Swaminathan, Srinivasan; Ko, Yoon Seok; Lee, Young-Su; Kim, Dong-Ik

2017-11-01

Two Fe-22 wt% Cr ferritic stainless steels containing varying concentrations of La (0.14 or 0.52 wt%), Cu (0.17 or 1.74 wt%) and B (48 or 109 ppm) are investigated with respect to oxidation behavior and high temperature area specific resistance (ASR) of the surface oxide scales. To determine the oxidation resistance of developed steels, continuous isothermal oxidation is carried out at 800 °C in air, for 2000 h, and their thermally grown oxide scale is characterized using dynamic SIMS, SEM/EDX, XRD and GI-XRD techniques. To assess their electrical performance, the ASR measurement by four-point probe method is conducted at 800 °C in air, for 400 h. In higher La content steel, the La-oxides at the scale/alloy interface promotes the oxygen transport which resulted in sub-surface oxidation of Mn, Cr, Ti and Al. Moreover, the inward growth of oxides contributes to increase of Fe-Cr alloy protrusions within the scale, which reduced the ASR. In contrast, sub-surface oxidation is reduced in high Cu-alloyed steel by segregated Cu at the scale/alloy interface. Thus, addition of Cu is effective to oxidation resistance and also to better electrical performance. However, no obvious impact of B on the scale sequence and/or ASR is observed.

On the Specific Role of Microstructure in Governing Cyclic Fatigue, Deformation, and Fracture Behavior of a High-Strength Alloy Steel

NASA Astrophysics Data System (ADS)

Manigandan, K.; Srivatsan, T. S.

2015-06-01

In this paper, the results of an experimental study that focused on evaluating the conjoint influence of microstructure and test specimen orientation on fully reversed strain-controlled fatigue behavior of the high alloy steel X2M are presented and discussed. The cyclic stress response of this high-strength alloy steel revealed initial hardening during the first few cycles followed by gradual softening for most of fatigue life. Cyclic strain resistance exhibited a linear trend for the variation of elastic strain amplitude with reversals to failure, and plastic strain amplitude with reversals to failure. Fracture morphology was the same at the macroscopic level over the entire range of cyclic strain amplitudes examined. However, at the fine microscopic level, the alloy steel revealed fracture to be essentially ductile with features reminiscent of predominantly "locally" ductile and isolated brittle mechanisms. The mechanisms governing stress response at the fine microscopic level, 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.

Partial-Isothermally-Treated Low Alloy Ultrahigh Strength Steel with Martensitic/Bainitic Microstructure

NASA Astrophysics Data System (ADS)

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.

Assessment of precipitation in alloy steel using nonlinear Rayleigh surface waves

NASA Astrophysics Data System (ADS)

Thiele, Sebastian; Matlack, Kathryn H.; Kim, Jin-Yeon; Qu, Jianmin; Wall, James J.; Jacobs, Laurence J.

2014-02-01

Nonlinear ultrasonic waves have shown to be sensitive to various microstructural changes in metals including coherent precipitates; these precipitates introduce a strain field in the lattice structure. The thermal aging of certain alloy steels leads to the formation of coherent precipitates, which pin dislocations and contribute to the generation of a second harmonic component. A precipitate hardenable material namely 17-4 PH stainless steel is thermally treated in this research to obtain different precipitation stages, and then the influence of precipitates on the acoustic nonlinearity parameter is assessed. Conclusions about the microstrucutural changes in the material are drawn based on the results from a nonlinear Rayleigh surface wave measurement and complementary thermo-electric power, hardness and ultrasonic velocity measurements. The results show that the nonlinear parameter is sensitive to coherent precipitates in the material and moreover that precipitation characteristics can be characterized based on the obtained experimental data.

Elastic properties of paramagnetic austenitic steel at finite temperature: Longitudinal spin fluctuations in multicomponent alloys

NASA Astrophysics Data System (ADS)

Dong, Zhihua; Schönecker, Stephan; Chen, Dengfu; Li, Wei; Long, Mujun; Vitos, Levente

2017-11-01

We propose a first-principles framework for longitudinal spin fluctuations (LSFs) in disordered paramagnetic (PM) multicomponent alloy systems and apply it to investigate the influence of LSFs on the temperature dependence of two elastic constants of PM austenitic stainless steel Fe15Cr15Ni. The magnetic model considers individual fluctuating moments in a static PM medium with first-principles-derived LSF energetics in conjunction with describing chemical disorder and randomness of the transverse magnetic component in the single-site alloy formalism and disordered local moment (DLM) picture. A temperature-sensitive mean magnetic moment is adopted to accurately represent the LSF state in the elastic-constant calculations. We make evident that magnetic interactions between an LSF impurity and the PM medium are weak in the present steel alloy. This allows gaining accurate LSF energetics and mean magnetic moments already through a perturbation from the static DLM moments instead of a tedious self-consistent procedure. We find that LSFs systematically lower the cubic shear elastic constants c' and c44 by ˜6 GPa in the temperature interval 300-1600 K, whereas the predominant mechanism for the softening of both elastic constants with temperature is the magneto-volume coupling due to thermal lattice expansion. We find that non-negligible local magnetic moments of Cr and Ni are thermally induced by LSFs, but they exert only a small influence on the elastic properties. The proposed framework exhibits high flexibility in accurately accounting for finite-temperature magnetism and its impact on the mechanical properties of PM multicomponent alloys.

Development of new generation reduced activation ferritic-martenstic steels for advanced fusion reactors

DOE PAGES

Tan, Lizhen; Snead, Lance Lewis; Katoh, Yutai

2016-05-26

International development of reduced activation ferritic-martensitic (RAFM) steels has focused on 9 wt percentage Cr, which primarily contain M 23C 6 (M = Cr-rich) and small amounts of MX (M = Ta/V, X = C/N) precipitates, not adequate to maintain strength and creep resistance above ~500 °C. To enable applications at higher temperatures for better thermal efficiency of fusion reactors, computational alloy thermodynamics coupled with strength modeling have been employed to explore a new generation RAFM steels. The new alloys are designed to significantly increase the amount of MX nanoprecipitates, which are manufacturable through standard and scalable industrial steelmaking methods.more » Preliminary experimental results of the developed new alloys demonstrated noticeably increased amount of MX, favoring significantly improved strength, creep resistance, and Charpy impact toughness as compared to current RAFM steels. Furthermore, the strength and creep resistance were comparable or approaching to the lower bound of, but impact toughness was noticeably superior to 9–20Cr oxide dispersion-strengthened ferritic alloys.« less

High-Strength Low-Alloy Steel Strengthened by Multiply Nanoscale Microstructures

NASA Astrophysics Data System (ADS)

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.

Effect of microstructure on transformation-induced plasticity of silicon-containing low-alloy steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomita, Yoshiyuki; Morioka, Kojiro

1997-04-01

Fe-0.6C-1.5Si-0.8Mn steel was studied to determine the effect of the microstructure on transformation-induced plasticity (TRIP) of silicon-containing low-alloy steel. A remarkable increase in elongation through TRIP can develop in the steel subjected to the following heat treatments: (1) austemper combined with subcritical annealing (SA Aus-T): subcritical annealing at 993K followed by austempering at 673K and then light tempering (after austenitization at 1173K); (2) austemper coupled with interrupted quenching (IQ Aus-T): interrupted quenching at 533K followed by austempering at 673K and light tempering (after austenization at 1,173K). The SA Aus-T treatment produced the triple structures of carbide-free upper bainite, retained austenitemore » ({gamma}R), and free ferrite. As a result of the IQ Aus-T treatment, the triple structures of carbide-free upper bainite, {gamma}R, and tempered martensite appeared. The results are described and microstructural factors in TRIP are discussed.« less

Study of magnetism in Ni-Cr hardface alloy deposit on 316LN stainless steel using magnetic force microscopy

NASA Astrophysics Data System (ADS)

Kishore, G. V. K.; Kumar, Anish; Chakraborty, Gopa; Albert, S. K.; Rao, B. Purna Chandra; Bhaduri, A. K.; Jayakumar, T.

2015-07-01

Nickel base Ni-Cr alloy variants are extensively used for hardfacing of austenitic stainless steel components in sodium cooled fast reactors (SFRs) to avoid self-welding and galling. Considerable difference in the compositions and melting points of the substrate and the Ni-Cr alloy results in significant dilution of the hardface deposit from the substrate. Even though, both the deposit and the substrate are non-magnetic, the diluted region exhibits ferromagnetic behavior. The present paper reports a systematic study carried out on the variations in microstructures and magnetic behavior of American Welding Society (AWS) Ni Cr-C deposited layers on 316 LN austenitic stainless steels, using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The phase variations of the oscillations of a Co-Cr alloy coated magnetic field sensitive cantilever is used to quantitatively study the magnetic strength of the evolved microstructure in the diluted region as a function of the distance from the deposit/substrate interface, with the spatial resolution of about 100 nm. The acquired AFM/MFM images and the magnetic property profiles have been correlated with the variations in the chemical compositions in the diluted layers obtained by the energy dispersive spectroscopy (EDS). The study indicates that both the volume fraction of the ferromagnetic phase and its ferromagnetic strength decrease with increasing distance from the deposit/substrate interface. A distinct difference is observed in the ferromagnetic strength in the first few layers and the ferromagnetism is observed only near to the precipitates in the fifth layer. The study provides a better insight of the evolution of ferromagnetism in the diluted layers of Ni-Cr alloy deposits on stainless steel.

Preliminary Investigation of the Corrosion Behavior of Proprietary Micro-alloyed Steels in Aerated and Deaerated Brine Solutions

NASA Astrophysics Data System (ADS)

Onyeji, Lawrence; Kale, Girish

2017-12-01

The corrosion performance of fairly new generation of micro-alloyed steels was compared in different concentrations of aerated and deaerated brines. Electrochemical polarization, weight loss and surface analyses techniques were employed. The results showed a threshold of corrosion rate at 3.5 wt.% NaCl in both aerated and deaerated solutions. The average corrosion current density for steel B, for example, increased from 1.3 µA cm-2 in 1 wt.% NaCl to 1.5 µA cm-2 in 3.5 wt.% NaCl, but decreased to 1.4 µA cm-2 in 10 wt.% deaerated NaCl solutions. The aerated solutions exhibited an average of over 80% increase in corrosion current density in the respective concentrations when compared with the deaerated solution. These results can be attributed to the effects of dissolved oxygen (DO) which has a maximum solubility in 3.5 wt.% NaCl. DO as a depolarizer and electron acceptor in cathodic reactions accelerates anodic metal dissolution. The difference in carbon content and microstructures occasioned by thermo-mechanical treatment contributed to the witnessed variation in corrosion performance of the steels. Specifically, the results of the various corrosion techniques corroborated each other and showed that the corrosion rate of the micro-alloyed steels can be ranked as CRSteel A < CRX65 < CRSteel B < CRSteel C.

Hot cracking susceptibility of Alloy 52M weld overlays onto CF8 stainless steel

NASA Astrophysics Data System (ADS)

Chu, H. A.; Young, M. C.; Chu, H. C.; Tsay, L. W.; Chen, C.

2013-02-01

In this study, weld overlays of Alloy 52M (a nickel-based filler metal) onto CF8 stainless steel (SS) were performed using the gas tungsten arc welding process. Hot cracking in the weld overlays was observed particularly near the interfacial region of the Alloy 52M/CF8 weld overlay. In general, the hot cracks were most likely to occur at the sites with high dilution rates, e.g., at the weld start/end locations of a single pass or in the first and second passes in multi-pass overlays. The region near the weld interface between Alloy 52M and the CF8 SS had a higher hot cracking tendency than the other regions. It was found that the dilution rate and the formation of eutectic-type constituents (i.e., γ/NbC) both played significant roles in the determination of the hot cracking susceptibility of these weld overlays. Nevertheless, hot cracks were entirely eliminated by proper deposition of a SS buffer layer prior to overlaying with Alloy 52M.

Characterization and comparative analysis of the tensile properties of five tempered martensitic steels and an oxide dispersion strengthened ferritic alloy irradiated at ≈295 °C to ≈6.5 dpa

DOE PAGES

Maloy, Stuart A.; Saleh, Tarik A.; Anderoglu, Osman; ...

2015-08-06

Tensile test results at 25 and 300 °C on five 9-12Cr tempered martensitic steels and one 14Cr oxide dispersion strengthened alloy, that were side-by side irradiated to 6.5 dpa at 295 °C in the Advanced Test Reactor (ATR), are reported. The engineering stress–strain curves are analyzed to provide true stress–strain constitutive σ(ε) laws for all of these alloys. In the irradiated condition, the σ(ε) fall into categories of: strain softening, nearly perfectly plastic and strain hardening. Increases in yield stress (Δσ y) and reductions in uniform strain ductility (e u) are observed, where as the latter can be understood inmore » terms of the alloy's σ(ε) behavior. Increases in the average σ(ε) in the range of 0–10% strain are smaller than the corresponding Δσ y, and vary more from alloy to alloy. The data are analyzed to establish relations between Δσ y and coupled changes in the ultimate stresses as well as the effects of both test temperature and the unirradiated yield stress (σ yu). The latter shows that higher σ yu correlates with lower Δσ y. In five out of six cases the effects of irradiation are generally consistent with previous observations on these alloys. However, the particular heat of the 12Cr HT-9 tempered martensitic steel in this study has a much higher e u than observed for earlier heats. The reasons for this improved behavior are not understood and may be microstructural in origin. However, it is noted that the new heat of HT-9, which was procured under modern quality assurance standards, has lower interstitial nitrogen than previous heats. As a result, notably lower interstitial solute contents correlate with improved ductility and homogenous deformation in broadly similar steels.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

DebRoy, Tarasankar

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 amore » 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.« less

Alloy Effects on the Gas Nitriding Process

NASA Astrophysics Data System (ADS)

Yang, M.; Sisson, R. D.

2014-12-01

Alloy elements, such as Al, Cr, V, and Mo, have been used to improve the nitriding performance of steels. In the present work, plain carbon steel AISI 1045 and alloy steel AISI 4140 were selected to compare the nitriding effects of the alloying elements in AISI 4140. Fundamental analysis is carried out by using the "Lehrer-like" diagrams (alloy specific Lehrer diagram and nitriding potential versus nitrogen concentration diagram) and the compound layer growth model to simulate the gas nitriding process. With this method, the fundamental understanding for the alloy effect based on the thermodynamics and kinetics becomes possible. This new method paves the way for the development of new alloy for nitriding.

Joining of Aluminium Alloy and Steel by Laser Assisted Reactive Wetting

NASA Astrophysics Data System (ADS)

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.

76 FR 77770 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-14

...-Alloy Steel Pipe From Mexico: Final Results of Antidumping Duty Administrative Review AGENCY: Import... Department of Commerce (the Department) published the preliminary results of the administrative review of the...: Preliminary Results of Antidumping Duty Administrative Review, 76 FR 49437 (August 10, 2011) (Preliminary...

Effects of alloying on aging and hardening processes of steel with 20% nickel

NASA Technical Reports Server (NTRS)

Bogachev, I. N.; Zvigintsev, N. V.; Maslakova, T. M.

1981-01-01

Measurements of hardness, thermal emf, and electrical resistance were used to study the effects of Co, Mo, Ti and Al contents on aging and hardening processes in Fe 20%Ni steel. It is shown that the effects of these alloying elements differ substantially. Anomalies which arise in the temperature dependence of physical properties due to the presence of cobalt and molybdenum are reduced by the inclusion of titanium and aluminum (and vice versa).

Effect of Alloying on the Strength Properties and the Hardening Mechanisms of Nitrogen-Bearing Austenitic Steels after Hot Deformation and Annealing

NASA Astrophysics Data System (ADS)

Bannykh, I. O.

2017-11-01

The main mechanisms of hardening nitrogen-bearing austenitic steels that operate under various thermomechanical treatment conditions at various steel compositions are considered. The strength properties of the steels are shown to depend on the content of interstitial elements, namely, carbon and nitrogen, and the influence of these elements on the stacking fault energy is estimated. The ratios of the main alloying elements that favor an increase or a decrease in the stacking fault energy are found to achieve the desirable level of strain hardening provided that an austenitic structure of steel is retained.

Molybdenum-A Key Component of Metal Alloys

USGS Publications Warehouse

Kropschot, S.J.

2010-01-01

Molybdenum, whose chemical symbol is Mo, was first recognized as an element in 1778. Until that time, the mineral molybdenite-the most important source of molybdenum-was believed to be a lead mineral because of its metallic gray color, greasy feel, and softness. In the late 19th century, French metallurgists discovered that molybdenum, when alloyed (mixed) with steel in small quantities, creates a substance that is remarkably tougher than steel alone and is highly resistant to heat. The alloy was found to be ideal for making tools and armor plate. Today, the most common use of molybdenum is as an alloying agent in stainless steel, alloy steels, and superalloys to enhance hardness, strength, and resistance to corrosion.

Cyclic Strain Resistance, Stress Response, Fatigue Life, and Fracture Behavior of High Strength Low Alloy Steel 300 M

NASA Astrophysics Data System (ADS)

Manigandan, K.; Srivatsan, T. S.; Tammana, Deepthi; Poorgangi, Behrang; Vasudevan, Vijay K.

2014-05-01

The focus of this technical manuscript is a record of the specific role of microstructure and test specimen orientation on cyclic stress response, cyclic strain resistance, and cyclic stress versus strain response, deformation and fracture behavior of alloy steel 300 M. The cyclic strain amplitude-controlled fatigue properties of this ultra-high strength alloy steel revealed a linear trend for the variation of log elastic strain amplitude with log reversals-to-failure, and log plastic strain amplitude with log reversals-to-failure for both longitudinal and transverse orientations. Test specimens of the longitudinal orientation showed only a marginal improvement over the transverse orientation at equivalent values of plastic strain amplitude. Cyclic stress response revealed a combination of initial hardening for the first few cycles followed by gradual softening for a large portion of fatigue life before culminating in rapid softening prior to catastrophic failure by fracture. Fracture characteristics of test specimens of this alloy steel were different at both the macroscopic and fine microscopic levels over the entire range of cyclic strain amplitudes examined. Both macroscopic and fine microscopic observations revealed fracture to be a combination of both brittle and ductile mechanisms. The underlying mechanisms governing stress response, deformation characteristics, fatigue life, and final fracture behavior are presented and discussed in light of the competing and mutually interactive influences of test specimen orientation, intrinsic microstructural effects, deformation characteristics of the microstructural constituents, cyclic strain amplitude, and response stress.

Evaluation of mechanically alloyed Cu-based powders as filler alloy for brazing tungsten to a reduced activation ferritic-martensitic steel

NASA Astrophysics Data System (ADS)

de Prado, J.; Sánchez, M.; Ureña, A.

2017-07-01

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.

Influence of the thermodynamic parameters on the temper embrittlement of SA508 Gr.4N Ni-Cr-Mo low alloy steel with variation of Ni, Cr and Mn contents

NASA Astrophysics Data System (ADS)

Park, Sang-Gyu; Lee, Ki-Hyoung; Min, Ki-Deuk; Kim, Min-Chul; Lee, Bong-Sang

2012-07-01

It is well known that SA508 Gr.4N low alloy steel offers improved fracture toughness and strength compared to commercial low alloy steels such as SA508 Gr.3 Mn-Mo-Ni low alloy steel. In this study, the effects of Cr, Mn, and Ni on temper embrittlement in SA508 Gr.4N low alloy steel were evaluated from the viewpoint of thermodynamic parameters such as P diffusivity and C activity. The changes of the ductile-brittle transition temperatures before and after aging were correlated with varying alloying element content, and the diffusivity of P and the activity of C were calculated and correlated with the transition behaviors. The addition of Ni, Cr, and Mn reduce the resistance to temper embrittlement, showing increased Transition-Temperature Shift (TTS) and an increased fraction of intergranular fracture. Although the diffusivity of P is changed by the addition of alloying elements, it does not considerably affect the temper embrittlement. The Mn and Cr content in the matrix significantly reduce the C activity, with showing an inversely proportional relationship to TTS. The change of susceptibility to temper embrittlement caused by Cr and Mn addition could be explained by the variation of C activity. Unlike Cr and Mn, Ni has little effect on the temper embrittlement and C activity.

75 FR 69626 - Certain Welded Carbon Steel Standard Pipes and Tubes From India: Final Results of Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-15

... DEPARTMENT OF COMMERCE International Trade Administration [A-533-502] Certain Welded Carbon Steel... order on certain welded carbon steel standard pipes and tubes from India. The period of review is May 1... carbon steel standard pipes and tubes from India. See Certain Welded Carbon Steel Standard Pipes and...

The effect of alloying elements and microstructure on the strength and fracture resistance of pearlitic steel

NASA Astrophysics Data System (ADS)

Nakase, K.; Bernstein, I. M.

1988-11-01

The processes of ductile and brittle fracture in fully pearlitic steel and their relation to both the scale of the microstructure and the presence of substitutional alloy elements have been investigated at room temperature using smooth tensile and over a range of temperatures using V-notched Charpy impact specimens. The results show that the early stages of cracking, revealed in both types of specimen, are largely the result of shear cracking of the pearlite lamellae. These cracks grow and can reach a size when they impinge upon the prior austenite boundary; afterward the character of fracture can be either microvoid coalescence or cleavage, depending on test conditions and metallurgical variables. Further, the carbide plates of the pearlite lamellae can act as barriers to the movement of dislocations as is the case normally with grain boundaries. For pearlite an optimum spacing of approximately 0.2 μm resulting from a balance between carbide plate thickness and interlamellar spacing was found to enhance toughness, although such changes are much smaller than corresponding changes due to varying alloy elements. Specific alloy elements used herein strengthened the lamellar ferrite in pearlite, inhibiting the movement of dislocations while also usually decreasing the lamellar cementite plate thickness for the same spacing. This dual behavior results in enhanced resistance to the initiation and propagation of microcracks leading to an improvement in strength, ductility, and toughness. The most effective alloy elements for the composition ranges studied in fully pearlitic steels are Si and Ni for strength improvement, and Ni and Mn for toughness.

Microstructure and Mechanical Properties of a Low Alloyed MnB Cast Steel

NASA Astrophysics Data System (ADS)

Luo, Kaishuang; Bai, Bingzhe

2010-08-01

The microstructure and mechanical properties of a low alloyed MnB cast steel designed for coupler castings of trucks were studied. The results show that the microstructure of the MnB cast steel after water quenching is lath martensite and a small amount of massive islands in the matrix of lath martensite. The average size of the martensite packets is about 10 μm in length. Carbides precipitated dispersively at the tempering temperature of 450 °C. The carbides are slender and fibrous, of which the microstructure was θ-phase (Fe, Mn)3C characterized by TEM. The MnB cast steel has good hardenability and tempering stability. Excellent combination of strength, ductility and low-temperature toughness were obtained after water-quenching and 450 °C tempering: Rm = 960-1040 MPa, ReL = 880-900 MPa, A = 19-21%, Z = 56-58%. Especially, the impact energy of the Charpy V-Notch (CVN) specimens reached 70-88 J at -40 °C. The fracture mechanism is transcrystalline fracture both for ambient temperature uniaxial tensile test specimens and for CVN impact test specimens broken at -40 °C, where the whole surfaces were manifested as voids and dimples.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Behnamian, Yashar, E-mail: behnamia@ualberta.ca

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) inmore » 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.« less

Quantitative observations of hydrogen-induced, slow crack growth in a low alloy steel

NASA Technical Reports Server (NTRS)

Nelson, H. G.; Williams, D. P.

1973-01-01

Hydrogen-induced slow crack growth, da/dt, was studied in AISI-SAE 4130 low alloy steel in gaseous hydrogen and distilled water environments as a function of applied stress intensity, K, at various temperatures, hydrogen pressures, and alloy strength levels. At low values of K, da/dt was found to exhibit a strong exponential K dependence (Stage 1 growth) in both hydrogen and water. At intermediate values of K, da/dt exhibited a small but finite K dependence (Stage 2), with the Stage 2 slope being greater in hydrogen than in water. In hydrogen, at a constant K, (da/dt) sub 2 varied inversely with alloy strength level and varied essentially in the same complex manner with temperature and hydrogen pressure as noted previously. The results of this study provide support for most of the qualitative predictions of the lattice decohesion theory as recently modified by Oriani. The lack of quantitative agreement between data and theory and the inability of theory to explain the observed pressure dependence of slow crack growth are mentioned and possible rationalizations to account for these differences are presented.

Metallurgical/Alloy Optimization of High Strength and Wear Resistant Structural Quench and Tempered Steels

NASA Astrophysics Data System (ADS)

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.

76 FR 49437 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Preliminary Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

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...

On the toughness scatter in low alloy C-Mn steel samples fabricated using wire arc additive manufacturing

DOE PAGES

Sridharan, Niyanth S.; Noakes, Mark W.; Nycz, Andrzej; ...

2017-12-06

Low alloy carbon manganese (C-Mn) steel builds were fabricated using a wire based additive manufacturing system developed at Oak Ridge National Laboratory. Specimens were fabricated in the X,Y and Z direction and detailed mechanical testing was performed. The mechanical testing results showed a significant scatter in tensile ductility and significant variation in Charpy toughness. Further detailed microstructure characterization showed significant microstructural heterogeneity in builds fabricated in each direction. The scatter in mechanical properties was then rationalized based on the microstructural observations and the underlying changes in the local heat transfer conditions. Lastly, the results indicate that when fabricating parts usingmore » C-Mn low alloy steel welds the process parameters and tool path should be chosen such that the cooling rate from 800 °C to 500 °C is greater than 30 s to avoid formation of martensite austenite (MA) phases, which leads to toughness reductions.« less

On the toughness scatter in low alloy C-Mn steel samples fabricated using wire arc additive manufacturing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sridharan, Niyanth S.; Noakes, Mark W.; Nycz, Andrzej

Low alloy carbon manganese (C-Mn) steel builds were fabricated using a wire based additive manufacturing system developed at Oak Ridge National Laboratory. Specimens were fabricated in the X,Y and Z direction and detailed mechanical testing was performed. The mechanical testing results showed a significant scatter in tensile ductility and significant variation in Charpy toughness. Further detailed microstructure characterization showed significant microstructural heterogeneity in builds fabricated in each direction. The scatter in mechanical properties was then rationalized based on the microstructural observations and the underlying changes in the local heat transfer conditions. Lastly, the results indicate that when fabricating parts usingmore » C-Mn low alloy steel welds the process parameters and tool path should be chosen such that the cooling rate from 800 °C to 500 °C is greater than 30 s to avoid formation of martensite austenite (MA) phases, which leads to toughness reductions.« less

Influence of Al content on the corrosion resistance of micro-alloyed hot rolled steel as a function of grain size

NASA Astrophysics Data System (ADS)

Qaban, Abdullah; Naher, Sumsun

2018-05-01

High-strength low-alloy steel (HSLA) has been widely used in many applications involving automobiles, aerospace, construction, and oil and gas pipelines due to their enhanced mechanical and chemical properties. One of the most critical elements used to improve these properties is Aluminium. This work will explore the effect of Al content on the corrosion behaviour of hot rolled high-strength low-alloy steel as a function of grain size. The method of investigation employed was weight loss technique. It was obvious that the increase in Al content enhanced corrosion resistance through refinement of grain size obtained through AlN precipitation by pinning grain boundaries and hindering their growth during solidification which was found to be beneficial in reducing corrosion rate.

Characterization of an Additive Manufactured TiAl Alloy-Steel Joint Produced by Electron Beam Welding.

PubMed

Basile, Gloria; Baudana, Giorgio; Marchese, Giulio; Lorusso, Massimo; Lombardi, Mariangela; Ugues, Daniele; Fino, Paolo; Biamino, Sara

2018-01-17

In this work, the characterization of the assembly of a steel shaft into a γ-TiAl part for turbocharger application, obtained using Electron Beam Welding (EBW) technology with a Ni-based filler, was carried out. The Ti-48Al-2Nb-0.7Cr-0.3Si (at %) alloy part was produced by Electron Beam Melting (EBM). This additive manufacturing technology allows the production of a lightweight part with complex shapes. The replacement of Nickel-based superalloys with TiAl alloys in turbocharger automotive applications will lead to an improvement of the engine performance and a substantial reduction in fuel consumption and emission. The welding process allows a promising joint to be obtained, not affecting the TiAl microstructure. Nevertheless, it causes the formation of diffusive layers between the Ni-based filler and both steel and TiAl, with the latter side being characterized by a very complex microstructure, which was fully characterized in this paper by means of Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, and nanoindentation. The diffusive interface has a thickness of about 6 µm, and it is composed of several layers. Specifically, from the TiAl alloy side, we find a layer of Ti₃Al followed by Al₃NiTi₂ and AlNi₂Ti. Subsequently Ni becomes more predominant, with a first layer characterized by abundant carbide/boride precipitation, and a second layer characterized by Si-enrichment. Then, the chemical composition of the Ni-based filler is gradually reached.

New alloys to conserve critical elements

NASA Technical Reports Server (NTRS)

Stephens, J. R.

1978-01-01

Based on availability of domestic reserves, chromium is one of the most critical elements within the U.S. metal industry. New alloys having reduced chromium contents which offer potential as substitutes for higher chromium containing alloys currently in use are being investigated. This paper focuses primarily on modified Type 304 stainless steels having one-third less chromium, but maintaining comparable oxidation and corrosion properties to that of type 304 stainless steel, the largest single use of chromium. Substitutes for chromium in these modified Type 304 stainless steel alloys include silicon and aluminum plus molybdenum.

Effect of alloying elements and coiling temperature on the recrystallization behavior and the bainitic transformation in TRIP steels

NASA Astrophysics Data System (ADS)

Han, Seongho; Seong, Hwangoo; Ahn, Yeonsang; Garcia, C. I.; DeArdo, A. J.; Kim, Inbae

2009-08-01

The effects of alloying elements and coiling temperature on recrystallization behavior and bainitic transformation were investigated based on 0.07C-Mn-Cr-Nb steel with a low carbon equivalent. Based on the ferrite recrystallization behavior, the proper intercritical annealing temperature of all studied steels was suggested to produce TRIP steel with good strength and elongation balance. All steels coiled at 550 °C showed much faster ferrite recrystallization behavior than steels coiled at 700 °C. In addition to the coiling temperature, the effect of increasing carbon content on the ferrite recrystallization was minor at a coiling temperature of 550 °C, but much more prominent at a coiling temperature of 700 °C. The highest Mo added steel showed the best strength and elongation balance, and the highest carbon and Mo added steel showed the highest tensile strength at a coiling temperature of 550 °C. The steel containing a higher amount of elemental Al (0.7 wt.% Al) exhibited much better elongation than the lower Al added steel (0.04 wt.% Al) in TS 780 MPa grade, about 24 % and 19 %, respectively.

Dissimilar Joining of Stainless Steel and 5083 Aluminum Alloy Sheets by Gas Tungsten Arc Welding-Brazing Process

NASA Astrophysics Data System (ADS)

Cheepu, Muralimohan; Srinivas, B.; Abhishek, Nalluri; Ramachandraiah, T.; Karna, Sivaji; Venkateswarlu, D.; Alapati, Suresh; Che, Woo Seong

2018-03-01

The dissimilar joining using gas tungsten arc welding - brazing of 304 stainless steel to 5083 Al alloy had been conducted with the addition of Al-Cu eutectic filler metal. The interface microstructure formation between filler metal and substrates, and spreading of the filler metal were studied. The interface microstructure between filler metal and aluminum alloy characterized that the formation of pores and elongated grains with the initiation of micro cracks. The spreading of the liquid braze filler on stainless steel side packed the edges and appeared as convex shape, whereas a concave shape has been formed on aluminum side. The major compounds formed at the fusion zone interface were determined by using X-ray diffraction techniques and energy-dispersive X-ray spectroscopy analysis. The micro hardness at the weld interfaces found to be higher than the substrates owing to the presence of Fe2Al5 and CuAl2 intermetallic compounds. The maximum tensile strength of the weld joints was about 95 MPa, and the tensile fracture occurred at heat affected zone on weak material of the aluminum side and/or at stainless steel/weld seam interface along intermetallic layer. The interface formation and its effect on mechanical properties of the welds during gas tungsten arc welding-brazing has been discussed.

Welding of High-Strength Steels for Aircraft and Missile Applications

DTIC Science & Technology

1959-10-12

40 PRECIPITATION -HARDENING STAINLESS STEELS ...... .............. .. 40 Single-Treatment Martensitic Steelse ...metal. A survey of the procedures currently being used is presented. Low - Alloy Martensitic Steels AISI 4340, AMS 6434, XZOO, 300M, and 17-Z2AS all are...in roughly decreasing order of industry-wide interest: low - alloy martensitic steels , hot-work die steels , martensitic stainless steels , and

Mechanical properties of low-alloy-steels with bainitic microstructures and varying carbon content

NASA Astrophysics Data System (ADS)

Weber, A.; Klarner, J.; Vogl, T.; Schöngrundner, R.; Sam, G.; Buchmayr, B.

2016-03-01

Materials used in the oilfield industry are subjected to special conditions. These requirements for seamless steel tubes are between the priorities of strength, toughness and sour gas resistance. Steels with bainitic microstructure provide a great opportunity for those harsh environmental conditions. With different morphologies of bainite, like carbide free, upper or lower bainite, the interaction of high tensile strength and elongation is assumed to be better than with tempered martensite. To form carbide free bainite two ways of processing are proposed, isothermal holding with accurate time control or controlled continuous cooling. Both require knowledge of time-temperature transformation behaviour, which can be reached through a detailed alloying concept, focused on the influence of silicon to supress the carbide nucleation and chromium to stabilize the austenite fraction. The present work is based on three alloys with varying silicon and chromium contents. The carbide free microstructure is obtained by a continuous cooling path. Additionally different heat treatments were done to compare the inherent performance of the bainitic morphologies. The bainitic structures were characterized metallographically for their microstructure and the primary phase by means of transmission electron microscopy. The mechanical properties of carbide-free structures were analysed with quasi-static tensile tests and Charpy impact tests. Moreover, investigations about hydrogen embrittlement were done with focus on the effect of retained austenite. The results were ranked and compared qualitatively.

Water Droplet and Cavitation Erosion Behavior of Laser-Treated Stainless Steel and Titanium Alloy: Their Similarities

NASA Astrophysics Data System (ADS)

Mann, B. S.

2013-12-01

This article deals with water droplet and cavitation erosion behavior of diode laser-treated X10CrNiMoV1222 stainless steel and Ti6Al4V alloy. After laser surface treatment, the water droplet and cavitation erosion resistance (WDER and CER) of these materials improved significantly. The main reason for the improvement is the increased surface hardness and formation of fine-grained microstructures after laser surface treatment. It is observed that there is a similarity in both the phenomena. The WDER and CER can be correlated with a single mechanical property based on modified ultimate resilience (MUR) provided the laser-treated layers are free from microcracks and interface defects. The CER and WDER behavior of HPDL-treated X10CrNiMoV1222 stainless steel and Ti6Al4V alloy samples using different test equipment as per ASTM G32-2003 and ASTM G73-1978, their correlation with MUR, and their damage mechanism compared on the basis of XRD analyses, optical and scanning electron micrographs are discussed and reported in this article.

Friction Stir Spot Welding of Advanced High Strength Steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hovanski, Yuri; Grant, Glenn J.; Santella, M. L.

Friction stir spot welding techniques were developed to successfully join several advanced high strength steels. Two distinct tool materials were evaluated to determine the effect of tool materials on the process parameters and joint properties. Welds were characterized primarily via lap shear, microhardness, and optical microscopy. Friction stir spot welds were compared to the resistance spot welds in similar strength alloys by using the AWS standard for resistance spot welding high strength steels. As further comparison, a primitive cost comparison between the two joining processes was developed, which included an evaluation of the future cost prospects of friction stir spotmore » welding in advanced high strength steels.« less

Role of copper in precipitation hardening of high-alloy Cr-Ni cast steels

NASA Astrophysics Data System (ADS)

Gajewski, Mirosław

2006-02-01

The mechanism of strengthening with second-phase particles that results from heat treatment, i.e., precipitate hardening, plays an important role in modern alloys. The strengthening effect of such particles can result from their coherence with the matrix, inhibition of dislocation slip, inhibition of grain boundary slip, as well as hampering recovery processes due to dislocation network pinning. The results of investigations into high-alloy Cr-Ni-Cu cast steels precipitate hardened with highly dispersed ɛ phase particles are presented within. The influence of heat treatment on changes in microstructure, mechanical properties, and morphology of fracture surfaces obtained under loading have been analyzed. It has been demonstrated that, with the appropriate selection of heat treatment parameters, it is possible to control the precipitation of the hardening ɛ phase and, thus, to change the final mechanical and functional properties.

Comparison of spring characteristics of titanium-molybdenum alloy and stainless steel

PubMed Central

Salehi, Anahita; Asatourian, Armen

2017-01-01

Background Titanium-molybdenum alloy (TMA) and stainless steel (SS) wires are commonly used in orthodontics as arch-wires for tooth movement. However, plastic deformation phenomenon in these arch-wires seems to be a major concern among orthodontists. This study aimed to compare the mechanical properties of TMA and SS wires with different dimensions. Material and Methods Seventy-two wire samples (36 TMA and 36 SS) of three different sizes (19×25, 17×25 and 16×22) were analyzed in vitro, with 12 samples in each group. Various mechanical properties of the wires, including spring-back, bending moment and stiffness were determined using a universal testing machine. Student’s t-test showed statistically significant differences in the mean values of all the groups. In addition, metallographic comparison of SS and TMA wires was conducted under an optical microscope. Results The degree of stiffness of 16×22-sized SS and TMA springs was found to be 12±2 and 5±0.4, respectively, while the bending moment was estimated to be 1927±352 (gm-mm) and 932±16 (gm-mm), respectively; the spring-back index was determined to be 0.61±0.2 and 0.4±.09, respectively (p<0.001). There were no statistically significant differences in spring-back index in larger dimensions of the wires. Conclusions Systematic analysis indicated that springs made of TMA were superior compared to those made of SS. Although both from economic and functionality viewpoints the use of TMA is suggested, further clinical investigations are recommended. Key words:Bending moment, optical microscope, spring-back, stainless steel, stiffness, titanium‒molybdenum alloy. PMID:28149469

Flight Planning for the International Space Station-Levitation Observation of Dendrite Evolution in Steel Ternary Alloy Rapid Solidification

NASA Technical Reports Server (NTRS)

Flemings, M. C.; Matson, D. M.; Loser, W.; Hyers, R. W.; Rogers, J. R.; Curreri, Peter A. (Technical Monitor)

2002-01-01

The paper is an overview of the status and science for the LODESTARS (Levitation Observation of Dendrite Evolution in Steel Ternary Alloy Rapid Solidification) research project. The program is aimed at understanding how melt convection influences phase selection and the evolution of rapid solidification microstructures.

78 FR 34342 - Certain Circular Welded Non-Alloy Steel Pipe From Mexico: Final Results and Partial Rescission of...

Federal Register 2010, 2011, 2012, 2013, 2014

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...

Influence of Filler Alloy Composition and Process Parameters on the Intermetallic Layer Thickness in Single-Sided Cold Metal Transfer Welding of Aluminum-Steel Blanks

NASA Astrophysics Data System (ADS)

Silvayeh, Zahra; Vallant, Rudolf; Sommitsch, Christof; Götzinger, Bruno; Karner, Werner; Hartmann, Matthias

2017-11-01

Hybrid components made of aluminum alloys and high-strength steels are typically used in automotive lightweight applications. Dissimilar joining of these materials is quite challenging; however, it is mandatory in order to produce multimaterial car body structures. Since especially welding of tailored blanks is of utmost interest, single-sided Cold Metal Transfer butt welding of thin sheets of aluminum alloy EN AW 6014 T4 and galvanized dual-phase steel HCT 450 X + ZE 75/75 was experimentally investigated in this study. The influence of different filler alloy compositions and welding process parameters on the thickness of the intermetallic layer, which forms between the weld seam and the steel sheet, was studied. The microstructures of the weld seam and of the intermetallic layer were characterized using conventional optical light microscopy and scanning electron microscopy. The results reveal that increasing the heat input and decreasing the cooling intensity tend to increase the layer thickness. The silicon content of the filler alloy has the strongest influence on the thickness of the intermetallic layer, whereas the magnesium and scandium contents of the filler alloy influence the cracking tendency. The layer thickness is not uniform and shows spatial variations along the bonding interface. The thinnest intermetallic layer (mean thickness < 4 µm) is obtained using the silicon-rich filler Al-3Si-1Mn, but the layer is more than twice as thick when different low-silicon fillers are used.

Delamination Fracture Related to Tempering in a High-Strength Low-Alloy Steel

NASA Astrophysics Data System (ADS)

Yan, Wei; Sha, Wei; Zhu, Lin; Wang, Wei; Shan, Yi-Yin; Yang, Ke

2010-01-01

The delamination or splitting of mechanical test specimens of rolled steel plate is a phenomenon that has been studied for many years. In the present study, splitting during fracture of tensile and Charpy V-notch (CVN) test specimens is examined in a high-strength low-alloy plate steel. It is shown that delamination did not occur in test specimens from plate in the as-rolled condition, but was severe in material tempered in the temperature range 500 °C to 650 °C. Minor splitting was seen after heating to 200 °C, 400 °C, and 700 °C. Samples that had been triple quenched and tempered to produce a fine equiaxed grain size also did not exhibit splitting. Microstructural and preferred orientation studies are presented and are discussed as they relate to the splitting phenomenon. It is concluded that the elongated as-rolled grains and grain boundary embrittlement resulting from precipitates (carbides and nitrides) formed during reheating were responsible for the delamination.

Experimental investigation of various surface integrity aspects in hard turning of AISI 4340 alloy steel with coated and uncoated cermet

NASA Astrophysics Data System (ADS)

Das, Anshuman; Patel, S. K.; Sateesh Kumar, Ch.; Biswal, B. B.

2018-03-01

The newer technological developments are exerting immense pressure on domain of production. These fabrication industries are busy finding solutions to reduce the costs of cutting materials, enhance the machined parts quality and testing different materials, which can be made versatile for cutting materials, which are difficult for machining. High-speed machining has been the domain of paramount importance for mechanical engineering. In this study, the variation of surface integrity parameters of hardened AISI 4340 alloy steel was analyzed. The surface integrity parameters like surface roughness, micro hardness, machined surface morphology and white layer of hardened AISI 4340 alloy steel were compared using coated and uncoated cermet inserts under dry cutting condition. From the results, it was deduced that coated insert outperformed uncoated one in terms of different surface integrity characteristics.

Influence of mill scale and rust layer on the corrosion resistance of low-alloy steel in simulated concrete pore solution

NASA Astrophysics Data System (ADS)

Shi, Jin-jie; Ming, Jing

2017-01-01

Electrochemical impedance spectroscopy, cyclic potentiodynamic polarization measurements, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to investigate the influence of mill scale and rust layer on the passivation capability and chloride-induced corrosion behaviors of conventional low-carbon (LC) steel and low-alloy (LA) steel in simulated concrete pore solution. The results show that mill scale exerts different influences on the corrosion resistance of both steels at various electrochemical stages. We propose that the high long-term corrosion resistance of LA steel is mainly achieved through the synergistic effect of a gradually formed compact, adherent and well-distributed Cr-enriched inner rust layer and the physical barrier protection effect of mill scale.

Grindability of dental magnetic alloys.

PubMed

Hayashi, Eisei; Kikuchi, Masafumi; Okuno, Osamu; Kimura, Kohei

2005-06-01

In this study, the grindability of cast magnetic alloys (Fe-Pt-Nb magnetic alloy and magnetic stainless steel) was evaluated and compared with that of conventional dental casting alloys (Ag-Pd-Au alloy, Type 4 gold alloy, and cobalt-chromium alloy). Grindability was evaluated in terms of grinding rate (i.e., volume of metal removed per minute) and grinding ratio (i.e., volume ratio of metal removed compared to wheel material lost). Solution treated Fe-Pt-Nb magnetic alloy had a significantly higher grinding rate than the aged one at a grinding speed of 750-1500 m x min(-1). At 500 m x min(-1), there were no significant differences in grinding rate between solution treated and aged Fe-Pt-Nb magnetic alloys. At a lower speed of 500 m x min(-1) or 750 m x min(-1), it was found that the grinding rates of aged Fe-Pt-Nb magnetic alloy and stainless steel were higher than those of conventional casting alloys.

Special Features of Structure Formation in Pipes from Medium-Carbon Low-Alloy Steel 32G2F Under Heat Treatment

NASA Astrophysics Data System (ADS)

Stepanov, A. I.; Belikov, S. V.; Musikhin, S. A.; Burmasov, S. P.; Popov, A. A.

2017-03-01

Special features of formation of structure and properties of seamless pipes from medium-carbon low-alloy steel for oil and gas applications are considered and associated with chemical inhomogeneity of the metal of the pipes.

Irradiation effects on 17-7 PH stainless steel, A-201 carbon steel, and titanium-6-percent-aluminum-4-percent-vanadium alloy

NASA Technical Reports Server (NTRS)

Hasse, R. A.; Hartley, C. B.

1972-01-01

Irradiation effects on three materials from the NASA Plum Brook Reactor Surveillance Program were determined. An increase of 105 K in the nil-ductility temperature for A-201 steel was observed at a fluence of approximately 3.1 x 10 to the 18th power neutrons/sq cm (neutron energy E sub n greater than 1.0 MeV). Only minor changes in the mechanical properties of 17-7 PH stainless steel were observed up to a fluence of 2 x 10 to the 21st power neutrons/sq cm (E sub n greater than 1.0 MeV). The titanium-6-percent-aluminum-4-percent-vanadium alloy maintained its notch toughness up to a fluence of 1 x 10 to the 21st power neutrons/sq cm (E sub n greater than 1.0 MeV).

Tensile and pack compressive tests of some sheets of aluminum alloy, 1025 carbon steel, and chromium-nickel steel

NASA Technical Reports Server (NTRS)

Atchison, C S; Miller, James A

1942-01-01

Tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves are given for longitudinal and transverse specimens of 17S-T, 24S-T, and 24S-RT aluminum-alloy sheet in thicknesses from 0.032 to 0.081 inch, 1025 carbon steel sheet in thicknesses of 0.054 and 0.120 inch, and chromium-nickel steel sheet in thicknesses form 0.020 to 0.0275 inch. Significant differences were found between the tensile and the compressive stress-strain curves, and also the corresponding corollary curves; similarly, differences were found between the curves for the longitudinal and transverse directions. These differences are of particular importance in considering the compressive strength of aircraft structures made of thin sheet. They are explored further for the case of compression by giving tangent modulus-stress curves in longitudinal and transverse compression and dimensionless curves of the ratio of tangent modulus to Young's modulus and of the ratio of reduced modulus for a rectangular section to Young's modulus, both plotted against the ratio of stress to secant yield strength.

Wear of tin coating and Al-Si alloy substrate against carburized steel under mixed lubrication

NASA Astrophysics Data System (ADS)

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.

Effects of silicon and titanium on the corrosion of low-alloy steels in a simulated coal gasification environment at 600 C

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soler, J.L.J.; Baxter, D.J.; Norton, J.F.

1999-12-01

Results of corrosion tests carried out on a series of Fe-12% Cr alloys in coal gasification environments t 600 C were studied. Effects of Si and Ti on corrosion resistance were assessed using data obtained from a commercial 12% Cr alloy, type 410 (UNS S41000), three specially cast model 12% Cr alloys containing 2.7% Si with Ti levels of 0%, 0.4% and 0.7%, respectively, and a higher alloy (type 28 [UNS N08028]) heat exchanger steel. Corrosion tests were carried out using simulated dry-feed entrained slagging gasifier gas The gas (64% carbon monoxide [CO], 3.8% carbon dioxide [CO{sub 2}], 0.8% hydrogenmore » sulfide [H{sub 2}S], and balance H{sub 2} [in vol%]) was premixed and passed over the test pieces at a rate high enough to prevent thermodynamic equilibrium achievement. Results showed that Si had a strongly beneficial influence on corrosion resistance. Ti, depending upon the amount added, exerted a positive or negative influence on corrosion resistance and reduced problems associated with workability. The kinetics of corrosion were presented in terms of weight-change and metal-loss measurements, the synergistic influences of Si and Ti were discussed, and corrosion resistance was compared with that exhibited by a commercial 12% Cr steel and type 28, the higher alloy material.« less

Steel selection for UBC steel bridge

NASA Astrophysics Data System (ADS)

Liu, Haoyu

2018-03-01

This report conducts a material selection of different types of steel for UBC Steel Bridge Team. I am a third-year material engineering student, so the result from this material selection can only be taken into consideration but not fully adopted. As part of my academic journey, it is possible for technical mistakes in this material selection process. The mechanic properties are the most effective category of properties, making it necessary to be justified from the steel bridge design and chosen in accordance with the objective of the team. An introduction for currently-used steel properties and the expected steel properties is provided. The examination focus on how different alloy compositions of steel changes its properties. The properties of the steel are examined in three main aspects: hardness, strength, and toughness. The results suggest that more nickel, manganese, and chromium in the steel provide better steel for the team to use. Further research is needed if a more precise material selection is required.

Fracture-tough, corrosion-resistant bearing steels

NASA Technical Reports Server (NTRS)

Olson, Gregory B.

1990-01-01

The fundamental principles allowing design of stainless bearing steels with enhanced toughness and stress corrosion resistance has involved both investigation of basic phenomena in model alloys and evaluation of a prototype bearing steel based on a conceptual design exercise. Progress in model studies has included a scanning Auger microprobe (SAM) study of the kinetics of interfacial segregation of embrittling impurities which compete with the kinetics of alloy carbide precipitation in secondary hardening steels. These results can define minimum allowable carbide precipitation rates and/or maximum allowable free impurity contents in these ultrahigh strength steels. Characterization of the prototype bearing steel designed to combine precipitated austenite transformation toughening with secondary hardening shows good agreement between predicted and observed solution treatment response including the nature of the high temperature carbides. An approximate equilibrium constraint applied in the preliminary design calculations to maintain a high martensitic temperature proved inadequate, and the solution treated alloy remained fully austenitic down to liquid nitrogen temperature rather than transforming above 200 C. The alloy can be martensitically transformed by cryogenic deformation, and material so processed will be studied further to test predicted carbide and austenite precipitation behavior. A mechanistically-based martensitic kinetic model was developed and parameters are being evaluated from available kinetic data to allow precise control of martensitic temperatures of high alloy steels in future designs. Preliminary calculations incorporating the prototype stability results suggest that the transformation-toughened secondary-hardening martensitic-stainless design concept is still viable, but may require lowering Cr content to 9 wt. pct. and adding 0.5 to 1.0 wt. pct. Al. An alternative design approach based on strain-induced martensitic transformation during

Co-reduction of Copper Smelting Slag and Nickel Laterite to Prepare Fe-Ni-Cu Alloy for Weathering Steel

NASA Astrophysics Data System (ADS)

Guo, Zhengqi; Pan, Jian; Zhu, Deqing; Zhang, Feng

2018-02-01

In this study, a new technique was proposed for the economical and environmentally friendly recovery of valuable metals from copper smelting slag while simultaneously upgrading nickel laterite through a co-reduction followed by wet magnetic separation process. Copper slag with a high FeO content can decrease the liquidus temperature of the SiO2-Al2O3-CaO-MgO system and facilitate formation of liquid phase in a co-reduction process with nickel laterite, which is beneficial for metallic particle growth. As a result, the recovery of Ni, Cu, and Fe was notably increased. A crude Fe-Ni-Cu alloy with 2.5% Ni, 1.1% Cu, and 87.9% Fe was produced, which can replace part of scrap steel, electrolytic copper, and nickel as the burden in the production of weathering steel by an electric arc furnace. The study further found that an appropriate proportion of copper slag and nickel laterite in the mixture is essential to enhance the reduction, acquire appropriate amounts of the liquid phase, and improve the growth of the metallic alloy grains. As a result, the liberation of alloy particles in the grinding process was effectively promoted and the metal recovery was increased significantly in the subsequent magnetic separation process.

Effect of molybdenum additions on the microstructures and corrosion behaviours of 316L stainless steel-based alloys

DOE PAGES

Rahman, T.; Ebert, W. L.; Indacochea, J. E.

2018-02-28

Alloys were made by alloying 5, 10, 15, 17.5, and 20 wt % Mo with Type 316L stainless steel. Sigma phases containing 21–29 wt % Mo formed along the austenite grain boundaries with the addition of 5 wt % Mo and increased with additions up to 15 wt % Mo, but they decreased with further additions. Laves phases containing 33–40 wt % Mo co-precipitated at additions of 10 wt % Mo which increased with further Mo increases. The corrosion resistance, assessed by potentiodynamic polarisation in a 10 mM NaCl solution adjusted to pH 4, increased relative to Type 316L formore » alloys made with 5 and 10 wt % added Mo, but decreased with further additions due to preferential corrosion of the Laves phase. The alloy made with 10 wt % added Mo had the highest corrosion resistance due primarily to the high Mo content of the austenite.« less

Effect of molybdenum additions on the microstructures and corrosion behaviours of 316L stainless steel-based alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, T.; Ebert, W. L.; Indacochea, J. E.

Alloys were made by alloying 5, 10, 15, 17.5, and 20 wt % Mo with Type 316L stainless steel. Sigma phases containing 21–29 wt % Mo formed along the austenite grain boundaries with the addition of 5 wt % Mo and increased with additions up to 15 wt % Mo, but they decreased with further additions. Laves phases containing 33–40 wt % Mo co-precipitated at additions of 10 wt % Mo which increased with further Mo increases. The corrosion resistance, assessed by potentiodynamic polarisation in a 10 mM NaCl solution adjusted to pH 4, increased relative to Type 316L formore » alloys made with 5 and 10 wt % added Mo, but decreased with further additions due to preferential corrosion of the Laves phase. The alloy made with 10 wt % added Mo had the highest corrosion resistance due primarily to the high Mo content of the austenite.« less

24 CFR 200.949 - Building product standards and certification program for exterior insulated steel door systems.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Doors and Frames; (viii) ISDSI-107-80—Thermal Performance Standard for Insulated Steel Door Systems; (ix... certification program for exterior insulated steel door systems. 200.949 Section 200.949 Housing and Urban... program for exterior insulated steel door systems. (a) Applicable standards. (1) All Exterior Insulated...

21 CFR 872.3350 - Gold or stainless steel cusp.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or alloys...

21 CFR 872.3350 - Gold or stainless steel cusp.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or alloys...

21 CFR 872.3350 - Gold or stainless steel cusp.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or alloys...

21 CFR 872.3350 - Gold or stainless steel cusp.

Code of Federal Regulations, 2010 CFR

2010-04-01

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

21 CFR 872.3350 - Gold or stainless steel cusp.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gold or stainless steel cusp. 872.3350 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3350 Gold or stainless steel cusp. (a) Identification. A gold or stainless steel cusp is a prefabricated device made of austenitic alloys or alloys...

High temperature alloy

NASA Technical Reports Server (NTRS)

Frank, R. G.; Semmel, J. W., Jr.

1968-01-01

Molybdenum is substituted for tungsten on an atomic basis in a cobalt-based alloy, S-1, thus enabling the alloy to be formed into various mill products, such as tubing and steels. The alloy is weldable, has good high temperature strength and is not subject to embrittlement produced by high temperature aging.

75 FR 18153 - Certain Large Diameter Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Japan...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-09

... Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Japan: Extension of Time Limit for... review of the antidumping duty order on certain large diameter carbon and alloy seamless standard, line... Carbon and Alloy Seamless Standard, Line and Pressure Pipe from Japan: Extension of Time Limit for...

75 FR 27428 - Safety Standards for Steel Erection

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

... in National Highway System construction projects to comply with a number of standards, policies, and...://www.fhwa.dot.gov/bridge/lrfd/index.htm .) For projects involving bridge construction (e.g., temporary... of these requirements will enhance the safety of employees operating on or near structural steel...

[Stainless steels for medical instruments].

PubMed

Feofilov, R N

1981-01-01

Both in the USSR and abroad similar types of martensitic and austenitic stainless steel are used for the manufacture of medical instruments. Martensitic steel, the cheapest and most economically alloyed, has the best combination of properties necessary for medical instruments. The analysis of the Soviet and foreign experience in using different grades of steel for the production of medical instruments demonstrates the expediency and possibility of improving the quality of martensitic steel and rolled stock, as well as that of medical instruments manufactured from these materials, by improving, the operations of the metallurgical and technological processes and by specifying more precisely the requirements for medical instruments. The possibility and expediency of using, in some technically justified cases, lower grades of alloyed steel instead of grade 12X18H9T for clamps and other instruments made of stainless steel, as well as highly corrosive grades of steel for microinstruments, have been established.

Investigation of the Phase Formation of AlSi-Coatings for Hot Stamping of Boron Alloyed Steel

NASA Astrophysics Data System (ADS)

Veit, R.; Hofmann, H.; Kolleck, R.; Sikora, S.

2011-01-01

Hot stamping of boron alloyed steel is gaining more and more importance for the production of high strength automotive body parts. Within hot stamping of quenchenable steels the blank is heated up to austenitization temperature, transferred to the tool, formed rapidly and quenched in the cooled tool. To avoid scale formation during the heating process of the blank, the sheet metal can be coated with an aluminium-silicum alloy. The meltimg temperature of this coating is below the austenitization temperature of the base material. This means, that a diffusion process between base material and coating has to take place during heating, leading to a higher melting temperature of the coating. In conventional heating devices, like roller hearth furnaces, the diffusion process is reached by relatively low heating rates. New technologies, like induction heating, reach very high heating rates and offer great potentials for the application in hot stamping. Till now it is not proofed, that this technology can be used with aluminum-silicon coated materials. This paper will present the results of comparative heating tests with a conventional furnace and an induction heating device. For different time/temperature-conditions the phase formation within the coating will be described.

The Tribological Difference between Biomedical Steels and CoCrMo-Alloys

PubMed Central

Fischer, Alfons; Weiß, Sabine; Wimmer, Markus A.

2012-01-01

In orthopedic surgery different self-mating metal couples are used for sliding wear applications. Despite the fact that in mechanical engineering self-mating austenitic alloys often lead to adhesion and seizure in biomedical engineering the different grades of Co-base alloys show good clinical results e.g. as hip joints. The reason stems from the fact that they generate a so-called tribomaterial during articulation, which consists of a mixture of nanometer small metallic grains and organic substances from the interfacial medium, which act as boundary lubricant. Even though stainless steels also generate such a tribomaterial they were ruled out from the beginning already in the 1950 as “inappropriate”. On the basis of materials with a clinical track record this contribution shows that the cyclic creep characteristics within the shear zone underneath the tribomaterial are another important criterion for a sufficient wear behavior. By means of sliding wear and torsional fatigue tests followed by electron microscopy it is shown, that austenitic materials generate wear particles of either nano- or of microsize. The latter are produced by crack initiation and propagation within the shear fatigue zone which is related to the formation of subsurface dislocation cells and, therefore, by the fact that a Ni-containing CrNiMo solid solution allows for wavy-slip. In contrast to this a Ni-free CrMnMo solid solution with further additions of C and N only shows planar slip. This leads to the formation of nanosize wear particles and distinctly improves the wear behavior. Still the latter does not fully achieve that of CoCrMo, which also shows solely planar-slip behavior. This explains why for metallurgical reasons the Ni-containing 316L-type of steels had to fail in such boundary lubricated sliding wear tribosystems. PMID:22498283

Assessment of Boron Steels for Army Use

DTIC Science & Technology

1978-11-01

I IA-79-0120 5 ys-g Aofc34V5 TECHNICAL LIBRARY AD ASSESSMENT OF BORON STEELS FOR ARMVlysr 3 ,% gL&tm tew^ / „»-^~ « "’"s4...ej ASSESSMENT OF BORON STEELS FOR ARMY USE 5. TYPE OF REPORT & PERIOD COVERED Final Report 6 PERFORMING ORG. REPORT NUMBER 7...reverse side 11 necessery rmd identify by block number) Boron steels Alloy conservation Alloy substitution Materials shortages 20. ABSTRACT

A Metallurgical Investigation of the Direct Energy Deposition Surface Repair of Ferrous Alloys

NASA Astrophysics Data System (ADS)

Marya, Manuel; Singh, Virendra; Hascoet, Jean-Yves; Marya, Surendar

2018-02-01

Among additive manufacturing (AM) processes, the direct energy deposition (DED) by laser is explored to establish its applicability for the repair of ferrous alloys such as UNS G41400 low-alloy steel, UNS S41000 martensitic stainless steel, UNS S17400 precipitation-strengthened martensitic stainless steel, and UNS S32750 super-duplex stainless steel. Unlike plating, thermal spray, and conventional cladding weld, DED laser powder deposition offers potential advantages, e.g., thin deposits, limited dilutions, narrow heat-affected zones (HAZ), potentially improved surface properties. In this investigation, all AM deposits were completed with an IREPA CLAD™ system using a powder feed of UNS N06625, an alloy largely selected for its outstanding corrosion resistance. This investigation first addresses topological aspects of AM deposits (including visual imperfections) before focusing on changes in microstructure, microhardness, chemical composition across AM deposits and base materials. It has been established that dense, uniform, hard ( 300 HVN), crack-free UNS N06625-compliant AM deposits of fine dendritic microstructures are reliably produced. However, except for the UNS S32750 steel, a significant martensitic hardening was observed in the HAZs of UNS G41400 ( 650 HVN), UNS S41000 ( 500 HVN), and UNS S17400 ( 370 HVN). In summary, this investigation demonstrates that the DED laser repair of ferrous parts with UNS N06625 may restore damaged surfaces, but it also calls for cautions and complementary investigations for alloys experiencing a high HAZ hardening, for which industry standard recommendations are exceeded and lead to an increased risk of delayed cracking in corrosive environments.

Predicting the Oxidation/Corrosion Performance of Structural Alloys in Supercritical CO 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, Ian; Kung, Steven; Shingledecker, John

This project was the first research to address oxidation of alloys under supercritical CO 2 conditions relevant to a semi-open Allam Cycle system. The levels of impurities expected in the CO 2 for typical operation were determined by thermodynamic and mass balance calculations, and a test rig was assembled and used to run corrosion tests at temperatures from 650 to 750°C in CO 2 at 200 bar for up to 5,000h, with and without impurities. Oxidation rates were measured for seven alloys representing high-strength ferritic steels, standard austenitic steels, and Ni-based alloys with higher-temperature capabilities. The very thin, protective scalesmore » formed on the high-temperature alloys provided significant challenges in characterization and thickness measurement. The rates of mass gain and scale thickening were possibly slower when oxidizing impurities were present in the sCO 2, and the scale morphologies formed on the ferritic and austenitic steels were consistent with expectations, and similar to those formed in high-pressure steam, with some potential influences of C. Some surface hardening (possibly due to carbon uptake) was identified in ferritic steels Grade 91 and VM12, and appeared more severe in commercially-pure CO 2. Hardening was also observed in austenitic steel TP304H, but that in HR3C appeared anomalous, probably the result of work-hardening from specimen preparation. No hardening was found in Ni-base alloys IN617 and IN740H. An existing EPRI Oxide Exfoliation Model was modified for this application and used to evaluate the potential impact of the scales grown in sCO 2 on service lifetimes in compact heat exchanger designs. Results suggested that reduction in flow area by simple oxide growth as well as by accumulation of exfoliated scale may have a major effect on the design of small-channel heat exchangers. In addition, the specific oxidation behavior of each alloy strongly influences the relationship of channel wall thickness to service lifetime.« less

Spectrophotometric determination of titanium with tannin and thioglycollic acid and its application to titanium-treated steels and ferrous and non-ferrous alloys.

PubMed

Banerjee, S

1986-04-01

A sensitive spectrophotometric method for the determination of titanium by formation of its complex with tannin and thioglycollic acid at pH 4 has been developed. The intense yellow colour is measured at 400 nm and the system obeys Beer's law over the range 0.2-5 ppm titanium in the solution measured. The method is applicable to titanium-treated steels, stainless steels, permanent magnet alloys and duralumin alloys. The interference of Co, Ni, Cr, Mn, V, Mo and W can be eliminated by prior separation of titanium by controlled addition of cupferron in the presence of thioglycollic acid (TGA). Copper can be quantitatively separated by precipitation with TGA and determined complexometrically with EDTA, with PAN as indicator. Niobium interferes even in traces.

Computational Modeling Develops Ultra-Hard Steel

NASA Technical Reports Server (NTRS)

2007-01-01

Glenn Research Center's Mechanical Components Branch developed a spiral bevel or face gear test rig for testing thermal behavior, surface fatigue, strain, vibration, and noise; a full-scale, 500-horsepower helicopter main-rotor transmission testing stand; a gear rig that allows fundamental studies of the dynamic behavior of gear systems and gear noise; and a high-speed helical gear test for analyzing thermal behavior for rotorcraft. The test rig provides accelerated fatigue life testing for standard spur gears at speeds of up to 10,000 rotations per minute. The test rig enables engineers to investigate the effects of materials, heat treat, shot peen, lubricants, and other factors on the gear's performance. QuesTek Innovations LLC, based in Evanston, Illinois, recently developed a carburized, martensitic gear steel with an ultra-hard case using its computational design methodology, but needed to verify surface fatigue, lifecycle performance, and overall reliability. The Battelle Memorial Institute introduced the company to researchers at Glenn's Mechanical Components Branch and facilitated a partnership allowing researchers at the NASA Center to conduct spur gear fatigue testing for the company. Testing revealed that QuesTek's gear steel outperforms the current state-of-the-art alloys used for aviation gears in contact fatigue by almost 300 percent. With the confidence and credibility provided by the NASA testing, QuesTek is commercializing two new steel alloys. Uses for this new class of steel are limitless in areas that demand exceptional strength for high throughput applications.

49 CFR 178.506 - Standards for metal drums other than steel or aluminum.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Standards for metal drums other than steel or... drums other than steel or aluminum. (a) The following are the identification codes for metal drums other than steel or aluminum: (1) 1N1 for a non-removable head metal drum; and (2) 1N2 for a removable head...

49 CFR 178.506 - Standards for metal drums other than steel or aluminum.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Standards for metal drums other than steel or... drums other than steel or aluminum. (a) The following are the identification codes for metal drums other than steel or aluminum: (1) 1N1 for a non-removable head metal drum; and (2) 1N2 for a removable head...

49 CFR 178.506 - Standards for metal drums other than steel or aluminum.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Standards for metal drums other than steel or... drums other than steel or aluminum. (a) The following are the identification codes for metal drums other than steel or aluminum: (1) 1N1 for a non-removable head metal drum; and (2) 1N2 for a removable head...

49 CFR 178.506 - Standards for metal drums other than steel or aluminum.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Standards for metal drums other than steel or... drums other than steel or aluminum. (a) The following are the identification codes for metal drums other than steel or aluminum: (1) 1N1 for a non-removable head metal drum; and (2) 1N2 for a removable head...

49 CFR 178.506 - Standards for metal drums other than steel or aluminum.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Standards for metal drums other than steel or... drums other than steel or aluminum. (a) The following are the identification codes for metal drums other than steel or aluminum: (1) 1N1 for a non-removable head metal drum; and (2) 1N2 for a removable head...

Effects of alloying elements and heat treatments on mechanical properties of Korean reduced-activation ferritic-martensitic steel

NASA Astrophysics Data System (ADS)

Chun, Y. B.; Kang, S. H.; Noh, S.; Kim, T. K.; Lee, D. W.; Cho, S.; Jeong, Y. H.

2014-12-01

As part of an alloy development program for Korean reduced-activation ferritic-martensitic (RAFM) steel, a total of 37 program alloys were designed and their mechanical properties were evaluated with special attention being paid to the effects of alloying elements and heat treatments. A reduction of the normalizing temperature from 1050 °C to 980 °C was found to have a positive effect on the impact resistance, resulting in a decrease in ductile-brittle transition-temperature (DBTT) of the program alloys by an average of 30 °C. The yield strength and creep rupture time are affected strongly by the tempering time at 760 °C but at the expense of ductility. Regarding the effects of the alloying elements, the addition of trace amounts of Zr enhances both the creep and impact resistance: the lowest DBTT was observed for the alloys containing 0.005 wt.% Zr, whereas the addition of 0.01 wt.% Zr extends the creep rupture-time under an accelerated condition. The enhanced impact resistance owing to the normalizing at lower temperature is attributed to a more refined grain structure, which provides more barriers to the propagation of cleavage cracks. Solution softening by Zr addition is suggested as a possible mechanism for enhanced resistance to both impact and creep of the program alloys.

Modification of Low-Alloy Steel Surface by High-Temperature Gas Nitriding Plus Tempering

NASA Astrophysics Data System (ADS)

Jiao, Dongling; Li, Minsong; Ding, Hongzhen; Qiu, Wanqi; Luo, Chengping

2018-02-01

The low-alloy steel was nitrided in a pure NH3 gas atmosphere at 640 660 °C for 2 h, i.e., high-temperature gas nitriding (HTGN), followed by tempering at 225 °C, which can produce a high property surface coating without brittle compound (white) layer. The steel was also plasma nitriding for comparison. The composition, microstructure and microhardness of the nitrided and tempered specimens were examined, and their tribological behavior investigated. The results showed that the as-gas-nitrided layer consisted of a white layer composed of FeN0.095 phase (nitrided austenite) and a diffusional zone underneath the white layer. After tempering, the white layer was decomposed to a nano-sized (α-Fe + γ'-Fe4N + retained austenite) bainitic microstructure with a high hardness of 1150HV/25 g. Wear test results showed that the wear resistance and wear coefficient yielded by the complex HTGN plus tempering were considerably higher and lower, respectively, than those produced by the conventional plasma nitriding.

Computational Design of a Novel Medium-Carbon, Low-Alloy Steel Microalloyed with Niobium

NASA Astrophysics Data System (ADS)

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.

Study of biocompatibility of medical grade high nitrogen nickel-free austenitic stainless steel in vitro.

PubMed

Li, Menghua; Yin, Tieying; Wang, Yazhou; Du, Feifei; Zou, Xingzheng; Gregersen, Hans; Wang, Guixue

2014-10-01

Adverse effects of nickel ions being released into the living organism have resulted in development of high nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also improves steel properties. The cell cytocompatibility, blood compatibility and cell response of high nitrogen nickel-free austenitic stainless steel were studied in vitro. The mechanical properties and microstructure of this stainless steel were compared to the currently used 316L stainless steel. It was shown that the new steel material had comparable basic mechanical properties to 316L stainless steel and preserved the single austenite organization. The cell toxicity test showed no significant toxic side effects for MC3T3-E1 cells compared to nitinol alloy. Cell adhesion testing showed that the number of MC3T3-E1 cells was more than that on nitinol alloy and the cells grew in good condition. The hemolysis rate was lower than the national standard of 5% without influence on platelets. The total intracellular protein content and ALP activity and quantification of mineralization showed good cell response. We conclude that the high nitrogen nickel-free austenitic stainless steel is a promising new biomedical material for coronary stent development. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of LIBS to the in-line process control of liquid high-alloy steel under pressure.

PubMed

Hubmer, Gerhard; Kitzberger, Reinhard; Mörwald, Karl

2006-05-01

A process optimization and control system called VAI-CON Chem has been developed that uses laser-induced breakdown spectroscopy (LIBS) to quasi-continuously chemically analyze liquid high-alloy steel under pressure. The beam from a Nd:YAG laser, located on safe ground and operating at its fundamental wavelength, is guided by a mirror system to a process tuyere below bath level. Passing through the approximately 1.5 m long tuyere, the beam is then focused onto the steel bath. Light emitted from the induced plasma passes back through the tuyere, which is coupled to a fiber optic cable that carries the information over a distance of approximately 10 m back to an Echelle spectrometer located beside the laser. Calibrations were performed using the complete system, located in a laboratory, during system testing. An induction furnace was used to simulate the AOD converter, wherein the samples were molten and superheated to a temperature of approximately 1600 degrees C and kept at a pressure of approximately 1.7 bar under an argon atmosphere. Twelve different high alloyed reference samples taken from normal AOD production with Fe concentrations of >48 wt.% and non-Fe element concentrations of up to 25 wt.% were available for calibration. The mean residual deviations (defined as the square root of the variance of the concentration ratios determined by LIBS and the reference element concentration ratios) obtained were close to those reported for other comparable high-alloy samples that were investigated at room temperature under normal atmospheric pressure.

A high-strength silicide phase in a stainless steel alloy designed for wear-resistant applications.

PubMed

Bowden, D; Krysiak, Y; Palatinus, L; Tsivoulas, D; Plana-Ruiz, S; Sarakinou, E; Kolb, U; Stewart, D; Preuss, M

2018-04-10

Hardfacing alloys provide strong, wear-resistant and corrosion-resistant coatings for extreme environments such as those within nuclear reactors. Here, we report an ultra-high-strength Fe-Cr-Ni silicide phase, named π-ferrosilicide, within a hardfacing Fe-based alloy. Electron diffraction tomography has allowed the determination of the atomic structure of this phase. Nanohardness testing indicates that the π-ferrosilicide phase is up to 2.5 times harder than the surrounding austenite and ferrite phases. The compressive strength of the π-ferrosilicide phase is exceptionally high and does not yield despite loading in excess of 1.6 GPa. Such a high-strength silicide phase could not only provide a new type of strong, wear-resistant and corrosion-resistant Fe-based coating, replacing more costly and hazardous Co-based alloys for nuclear applications, but also lead to the development of a new class of high-performance silicide-strengthened stainless steels, no longer reliant on carbon for strengthening.

76 FR 44608 - Carbon and Alloy Seamless Standard, Line, and Pressure Pipe From Japan and Romania; Scheduling of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-26

... Alloy Seamless Standard, Line, and Pressure Pipe From Japan and Romania; Scheduling of Expedited Five-Year Reviews Concerning the Antidumping Duty Orders on Carbon and Alloy Seamless Standard, Line, and... the antidumping duty orders on carbon and alloy seamless standard, line, and pressure pipe from Japan...

Improved the microstructures and properties of M3:2 high-speed steel by spray forming and niobium alloying

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, L.; Hou, L.G., E-mail: lghou@skl.ustb.edu.cn; Zhang, J.X.

The microstructures and properties of spray formed (SF) high-speed steels (HSSs) with or without niobium (Nb) addition were studied. Particular emphasis was placed on the effect of Nb on the solidification microstructures, decomposition of M{sub 2}C carbides, thermal stability and mechanical properties. The results show that spray forming can refine the cell size of eutectic carbides due to the rapid cooling effect during atomization. With Nb addition, further refinement of the eutectic carbides and primary austenite grains are obtained. Moreover, the Nb addition can accelerate the decomposition of M{sub 2}C carbides and increase the thermal stability of high-speed steel, andmore » also can improve the hardness and bending strength with slightly decrease the impact toughness. The high-speed steel made by spray forming and Nb alloying can give a better tool performance compared with powder metallurgy M3:2 and commercial AISI M2 high-speed steels. - Highlights: • Spray forming can effectively refine the microstructure of M3:2 steel. • Niobium accelerates the decomposition of M{sub 2}C carbides. • Niobium increases the hardness and bending strength of spray formed M3:2 steel. • Spray-formed niobium-containing M3:2 steel has the best tool performance.« less

The improvement of cryogenic mechanical properties of Fe-12 Mn and Fe-8 Mn alloy steels through thermal/mechanical treatments

NASA Technical Reports Server (NTRS)

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

1979-01-01

An investigation has been made to improve the low temperature mechanical properties of Fe-8Mn and Fe-12Mn-0.2 Ti alloy steels. A reversion annealing heat treatment in the two-phase (alpha + gamma) region following cold working has been identified as an effective treatment. In an Fe-12Mn-0.2Ti alloy a promising combination of low temperature (-196 C) fracture toughness and yield strength was obtained by this method. The improvement of properties was attributed to the refinement of grain size and to the introduction of a uniform distribution of retained austenite (gamma). It was also shown that an Fe-8Mn steel could be grain-refined by a purely thermal treatment because of its dislocated alpha-prime martensitic structure and absence of epsilon martensite. As a result, a significant reduction of ductile to brittle transition temperature was obtained.

Alloy Shrinkage factors for the investment casting of 17-4PH stainless steel parts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabau, Adrian S; Porter, Wallace D

2008-01-01

In this study, the alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. Dimensions of the die tooling, wax pattern, and casting were measured using a Coordinate Measurement Machine. For all the properties, the experimental data available in the literature did not cover the entire temperature range necessary for process simulation. A comparison between the predicted material property data measured property data is made. It was found that most material properties weremore » accurately predicted over the most of the temperature range of the process. Several assumptions were made in order to obtain a complete set of mechanical property data at high temperatures. Thermal expansion measurements for the 17-4PH alloy were conducted at heating and cooling. As a function of temperature, the thermal expansion for both the alloy and shell mold materials showed different evolution at heating and cooling. Thus, one generic simulation were performed with thermal expansion obtained at heating and another one with thermal expansion obtained at cooling. The alloy dimensions were obtained from numerical simulation results of solidification, heat transfer, and deformation phenomena. As compared with experimental results, the numerical simulation results for the shrinkage factors were slightly over-predicted.« less

Alloy Shrinkage Factors for the Investment Casting of 17-4PH Stainless Steel Parts

NASA Astrophysics Data System (ADS)

Sabau, Adrian S.; Porter, Wallace D.

2008-04-01

In this study, alloy shrinkage factors were obtained for the investment casting of 17-4PH stainless steel parts. For the investment casting process, unfilled wax and fused silica with a zircon prime coat were used for patterns and shell molds, respectively. The dimensions of the die tooling, wax pattern, and casting were measured using a coordinate measurement machine (CMM). For all the properties, the experimental data available in the literature did not cover the entire temperature range necessary for process simulation. A comparison between the predicted material property data and measured property data is made. It was found that most material properties were accurately predicted over most of the temperature range of the process. Several assumptions were made, in order to obtain a complete set of mechanical property data at high temperatures. Thermal expansion measurements for the 17-4PH alloy were conducted during heating and cooling. As a function of temperature, the thermal expansion for both the alloy and shell mold materials showed a different evolution on heating and cooling. Thus, one generic simulation was performed with thermal expansion obtained on heating, and another one was performed with thermal expansion obtained on cooling. The alloy dimensions were obtained from the numerical simulation results of the solidification, heat transfer, and deformation phenomena. As compared with experimental results, the numerical simulation results for the shrinkage factors were slightly overpredicted.

Nickel: makes stainless steel strong

USGS Publications Warehouse

Boland, Maeve A.

2012-01-01

Nickel is a silvery-white metal that is used mainly to make stainless steel and other alloys stronger and better able to withstand extreme temperatures and corrosive environments. Nickel was first identified as a unique element in 1751 by Baron Axel Fredrik Cronstedt, a Swedish mineralogist and chemist. He originally called the element kupfernickel because it was found in rock that looked like copper (kupfer) ore and because miners thought that "bad spirits" (nickel) in the rock were making it difficult for them to extract copper from it. Approximately 80 percent of the primary (not recycled) nickel consumed in the United States in 2011 was used in alloys, such as stainless steel and superalloys. Because nickel increases an alloy's resistance to corrosion and its ability to withstand extreme temperatures, equipment and parts made of nickel-bearing alloys are often used in harsh environments, such as those in chemical plants, petroleum refineries, jet engines, power generation facilities, and offshore installations. Medical equipment, cookware, and cutlery are often made of stainless steel because it is easy to clean and sterilize. All U.S. circulating coins except the penny are made of alloys that contain nickel. Nickel alloys are increasingly being used in making rechargeable batteries for portable computers, power tools, and hybrid and electric vehicles. Nickel is also plated onto such items as bathroom fixtures to reduce corrosion and provide an attractive finish.

Effects of Preheat on Weldments of NICOP Steel.

DTIC Science & Technology

1983-09-01

copper in this low alloy steel . Taken into solid solution in the austenite phase , the copper can precipitate as fine... low alloy steel was intro- duced which contains 1.0-1.3% copper with a maximum of 0.07% carbon. This steel is designated as AST4 A710 grade A for... ferrite has formed, some copper may precipitate as a fine epsilon copper phase in the ferrite as the solubility of

Influence of Hot Plastic Deformation in γ and (γ + α) Area on the Structure and Mechanical Properties of High-Strength Low-Alloy (HSLA) Steel.

PubMed

Sas, Jan; Kvačkaj, Tibor; Milkovič, Ondrej; Zemko, Michal

2016-11-30

The main goal of this study was to develop a new processing technology for a high-strength low-alloy (HSLA) steel in order to maximize the mechanical properties attainable at its low alloy levels. Samples of the steel were processed using thermal deformation schedules carried out in single-phase (γ) and dual-phase (γ + α) regions. The samples were rolled at unconventional finishing temperatures, their final mechanical properties were measured, and their strength and plasticity behavior was analyzed. The resulting microstructures were observed using optical and transmission electron microscopy (TEM). They consisted of martensite, ferrite and (NbV)CN precipitates. The study also explored the process of ferrite formation and its influence on the mechanical properties of the material.

Surface Modification of Micro-Alloyed High-Strength Low-Alloy Steel by Controlled TIG Arcing Process

NASA Astrophysics Data System (ADS)

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.

Brittle intermetallic compound makes ultrastrong low-density steel with large ductility.

PubMed

Kim, Sang-Heon; Kim, Hansoo; Kim, Nack J

2015-02-05

Although steel has been the workhorse of the automotive industry since the 1920s, the share by weight of steel and iron in an average light vehicle is now gradually decreasing, from 68.1 per cent in 1995 to 60.1 per cent in 2011 (refs 1, 2). This has been driven by the low strength-to-weight ratio (specific strength) of iron and steel, and the desire to improve such mechanical properties with other materials. Recently, high-aluminium low-density steels have been actively studied as a means of increasing the specific strength of an alloy by reducing its density. But with increasing aluminium content a problem is encountered: brittle intermetallic compounds can form in the resulting alloys, leading to poor ductility. Here we show that an FeAl-type brittle but hard intermetallic compound (B2) can be effectively used as a strengthening second phase in high-aluminium low-density steel, while alleviating its harmful effect on ductility by controlling its morphology and dispersion. The specific tensile strength and ductility of the developed steel improve on those of the lightest and strongest metallic materials known, titanium alloys. We found that alloying of nickel catalyses the precipitation of nanometre-sized B2 particles in the face-centred cubic matrix of high-aluminium low-density steel during heat treatment of cold-rolled sheet steel. Our results demonstrate how intermetallic compounds can be harnessed in the alloy design of lightweight steels for structural applications and others.

Microstructural and Mechanical Properties of Hot Roll Bonded Titanium Alloy/Low Carbon Steel Plate

NASA Astrophysics Data System (ADS)

Yu, Chao; Qi, Zi-chen; Yu, Hui; Xu, Cheng; Xiao, Hong

2018-03-01

In this paper, a titanium alloy and low carbon steel were bonded via hot rolling in a vacuum, and the effect of roll bonding temperature and reduction ratio on the microstructural and mechanical properties of the plate was studied. When the bonding temperature was between 850 and 1050 °C, the shear strength of the interface increased with an increasing reduction ratio from 18 to 70%. At a bonding temperature of 950 °C and at a rolling reduction ratio of 70%, the best bonding strength was obtained, and a shear fracture occurred on the low carbon steel matrix. At 1050 °C, brittle compounds, i.e., TiC, FeTi, and Fe2Ti, formed at the interface, which decreased the bonding strength. The large reduction ratio can break up compounds at the interface and extrude fresh metal for bonding, thereby increasing the bonding strength.

Fatigue Properties of Butt Welded Aluminum Alloy and Carbon Steel Joints by Friction Stirring

NASA Astrophysics Data System (ADS)

Okane, M.; Shitaka, T.; Ishida, M.; Chaki, T.; Yasui, T.; Fukumoto, M.

2017-05-01

The butt dissimilar joints of Al-Mg-Si alloy JIS A6063 and carbon steel JIS S45C by means of friction stir welding were prepared for investigating fatigue properties of the joints. The joining tool used has cemented carbide thread probe and a shoulder made of alloy tool steel. All the fatigue tests were carried out under a load-controlled condition with a load ratio R=0.1 in air at room temperature. From the experimental results, it was found that hardness near the interface in A6063 was lower than that of base material. Three types of fatigue fracture occurred even in case of same welding condition. The first one was fracture at boundary between the lower hardness region and base material in A6063, the second type was initiated in the stir zone by FSW process and the last one was fracture at interface. Fatigue strength in case of the second one was lower than others. Furthermore, to investigate the effect of heat treatment on fatigue properties of the dissimilar joints, fatigue tests were also carried out with using the specimens which were heat treated under the same condition to aging process in T6 treatment. Fatigue fracture was initiated at interface between A6063 and S45C in case of the heat treated specimen, but fatigue strength was improved approximately 25% as compared with that of the non-heat treated specimen.

Rolling contact fatigue of low hardness steel for slewing ring application

NASA Astrophysics Data System (ADS)

Knuth, Jason A.

This thesis discusses the rolling contact fatigue of steel utilized in anti-friction bearings, also referred to as slewing bearings. These slewing bearings are utilized in cranes, excavators, wind turbines and other similar applications. Five materials composed of two different material types were tested. The two material types were high carbon steel and medium carbon alloy steel. The test specimens were processed from forged rolled rings. Two machines were evaluated a ZF-RCF and 3-Ball test machine. The evaluation was to determine which machine can best simulate the application in which the slewing bearing is utilized. Initially, each specimen will be pretested to determine the appropriate testing direction from within the forged rolled rings. Pretesting is needed in order to establish consistent failure modes between samples. The primary goal of the test is to understand the life differences and failure modes between high carbon steel and medium carbon alloy steel. The high carbon steel ring was cut into two sections, one of which was stress relieved and the other was quenched and tempered. The medium carbon alloy steel was cut into three sections, all of which were quenched and tempered to different hardness levels. The test program was dynamically adjusted based upon the previous sample's life and load. An S-N curve was then established from the 5 materials tested at two target loads. The samples were run until the first sign of a crack was detected by an eddy current. At the completion of the rolling contact test, select sample's microstructure was evaluated for crack initiation location. The selected samples were divided into four groups which represent different maximum shear stress levels. These samples displayed indications of material deformation in which the high carbon steel experienced an increased amount of cold work when compared to medium carbon alloy steel. The life of the high carbon steel was nearly equivalent to the expected life of the medium

Biocompatibility and characterization of a Kolsterised(®) medical grade cobalt-chromium-molybdenum alloy.

PubMed

Conti, Malcolm Caligari; Karl, Andreas; Wismayer, Pierre Schembri; Buhagiar, Joseph

2014-01-01

High failure rates of cobalt-chromium-molybdenum (Co-Cr-Mo) metal-on-metal hip prosthesis were reported by various authors, probably due to the alloy's limited hardness and tribological properties. This thus caused the popularity of the alloy in metal-on-metal hip replacements to decrease due to its poor wear properties when compared with other systems such as ceramic-on-ceramic. S-phase surface engineering has become an industry standard when citing surface hardening of austenitic stainless steels. This hardening process allows the austenitic stainless steel to retain its corrosion resistance, while at the same time also improving its hardness and wear resistance. By coupling S-phase surface engineering, using the proprietary Kolsterising(®) treatment from Bodycote Hardiff GmbH, that is currently being used mainly on stainless steel, with Co-Cr-Mo alloys, an improvement in hardness and tribological characteristics is predicted. The objective of this paper is to analyze the biocompatibility of a Kolsterised(®) Co-Cr-Mo alloy, and to characterize the material surface in order to show the advantages gained by using the Kolsterised(®) material relative to the original untreated alloy, and other materials. This work has been performed on 3 fronts including; Material characterization, "In-vitro" corrosion testing, and Biological testing conforming to BS EN ISO 10993-18:2009 - Biological evaluation of medical devices. Using these techniques, the Kolsterised(®) cobalt-chromium-molybdenum alloys were found to have good biocompatibility and an augmented corrosion resistance when compared with the untreated alloy. The Kolsterised(®) samples also showed a 150% increase in surface hardness over the untreated material thus predicting better wear properties.

Biocompatibility and characterization of a Kolsterised® medical grade cobalt-chromium-molybdenum alloy

PubMed Central

Conti, Malcolm Caligari; Karl, Andreas; Wismayer, Pierre Schembri; Buhagiar, Joseph

2014-01-01

High failure rates of cobalt-chromium-molybdenum (Co-Cr-Mo) metal-on-metal hip prosthesis were reported by various authors, probably due to the alloy's limited hardness and tribological properties. This thus caused the popularity of the alloy in metal-on-metal hip replacements to decrease due to its poor wear properties when compared with other systems such as ceramic-on-ceramic. S-phase surface engineering has become an industry standard when citing surface hardening of austenitic stainless steels. This hardening process allows the austenitic stainless steel to retain its corrosion resistance, while at the same time also improving its hardness and wear resistance. By coupling S-phase surface engineering, using the proprietary Kolsterising® treatment from Bodycote Hardiff GmbH, that is currently being used mainly on stainless steel, with Co-Cr-Mo alloys, an improvement in hardness and tribological characteristics is predicted. The objective of this paper is to analyze the biocompatibility of a Kolsterised® Co-Cr-Mo alloy, and to characterize the material surface in order to show the advantages gained by using the Kolsterised® material relative to the original untreated alloy, and other materials. This work has been performed on 3 fronts including; Material characterization, “In-vitro” corrosion testing, and Biological testing conforming to BS EN ISO 10993–18:2009 - Biological evaluation of medical devices. Using these techniques, the Kolsterised® cobalt-chromium-molybdenum alloys were found to have good biocompatibility and an augmented corrosion resistance when compared with the untreated alloy. The Kolsterised® samples also showed a 150% increase in surface hardness over the untreated material thus predicting better wear properties. PMID:24451266

Human biomonitoring of chromium and nickel from an experimental exposure to manual metal arc welding fumes of low and high alloyed steel.

PubMed

Bertram, Jens; Brand, Peter; Schettgen, Thomas; Lenz, Klaus; Purrio, Ellwyn; Reisgen, Uwe; Kraus, Thomas

2015-05-01

The uptake and elimination of metals from welding fumes is currently not fully understood. In the Aachen Workplace Simulation Laboratory (AWSL) it is possible to investigate the impact of welding fumes on human subjects under controlled exposure conditions. In this study, the uptake and elimination of chromium or chromium (VI) respectively as well as nickel was studied in subjects after exposure to the emissions of a manual metal arc welding process using low or high alloyed steel. In this present study 12 healthy male non-smokers, who never worked as welders before, were exposed for 6h to welding fumes of a manual metal arc welding process. In a three-fold crossover study design, subjects were exposed in randomized order to either clean air, emissions from welding low alloyed steel, and emissions from welding high alloyed steel. Particle mass concentration of the exposure aerosol was 2.5mg m(-3). The content of chromium and nickel in the air was determined by analysing air filter samples on a high emission scenario. Urine analysis for chromium and nickel was performed before and after exposure using methods of human biomonitoring. There were significantly elevated chromium levels after exposure to welding fumes from high alloyed steel compared to urinary chromium levels before exposure to high alloyed welding fumes, as well as compared to the other exposure scenarios. The mean values increased from 0.27 µg l(-1) to 18.62 µg l(-1). The results were in good agreement with already existing correlations between external and internal exposure (German exposure equivalent for carcinogenic working materials EKA). The variability of urinary chromium levels was high. For urinary nickel no significant changes could be detected at all. Six-hour exposure to 2.5mg m(-3) high alloyed manual metal arc welding fumes lead to elevated urinary chromium levels far higher (7.11-34.16 µg l(-1)) than the German biological exposure reference value (BAR) of 0.6 µg l(-1) directly after

Anomolous Fatigue Crack Growth Phenomena in High-Strength Steel

NASA Technical Reports Server (NTRS)

Forth, Scott C.; James, Mark A.; Johnston, William M., Jr.; Newman, James C., Jr.

2004-01-01

The growth of a fatigue crack through a material is the result of a complex interaction between the applied loading, component geometry, three-dimensional constraint, load history, environment, material microstructure and several other factors. Previous studies have developed experimental and computational methods to relate the fatigue crack growth rate to many of the above conditions, with the intent of discovering some fundamental material response, i.e. crack growth rate as a function of something. Currently, the technical community uses the stress intensity factor solution as a simplistic means to relate fatigue crack growth rate to loading, geometry and all other variables. The stress intensity factor solution is a very simple linear-elastic representation of the continuum mechanics portion of crack growth. In this paper, the authors present fatigue crack growth rate data for two different high strength steel alloys generated using standard methods. The steels exhibit behaviour that appears unexplainable, compared to an aluminium alloy presented as a baseline for comparison, using the stress intensity factor solution.

Design of Fully Austenitic Medium Manganese Steels

NASA Astrophysics Data System (ADS)

Luan, G.; Volkova, O.; Mola, J.

2018-06-01

Due to their higher ferrite potential compared to high Mn twinning-induced plasticity (TWIP) steels, medium Mn steels usually exhibit austenitic-ferritic microstructures, which makes them suitable for third-generation advanced high-strength steel applications. Nevertheless, the strain hardening characteristics of medium Mn steels are inferior to those of fully austenitic high Mn steels. The present work introduces alloy design strategies to obtain fully austenitic medium Mn steels capable of the TWIP effect. To achieve a fully austenitic microstructure, the martensite start temperature is reduced by raising the C concentration to above 1 mass-%, which in turn facilitates the formation of cementite. The formation of cementite during cooling from austenitization temperature is counteracted by alloying with Al. Microstructural examination of slowly-cooled Fe‑Mn‑Al‑C and Fe‑Mn‑C steels indicated that Al changes the morphology of intergranular cementite from plate-shaped to equiaxed.

Spectral emissivity of candidate alloys for very high temperature reactors in high temperature air environment

NASA Astrophysics Data System (ADS)

Cao, G.; Weber, S. J.; Martin, S. O.; Sridharan, K.; Anderson, M. H.; Allen, T. R.

2013-10-01

Emissivity measurements for candidate alloys for very high temperature reactors were carried out in a custom-built experimental facility, capable of both efficient and reliable measurements of spectral emissivities of multiple samples at high temperatures. The alloys studied include 304 and 316 austenitic stainless steels, Alloy 617, and SA508 ferritic steel. The oxidation of alloys plays an important role in dictating emissivity values. The higher chromium content of 304 and 316 austenitic stainless steels, and Alloy 617 results in an oxide layer only of sub-micron thickness even at 700 °C and consequently the emissivity of these alloys remains low. In contrast, the low alloy SA508 ferritic steel which contains no chromium develops a thicker oxide layer, and consequently exhibits higher emissivity values.

Steel Structures for Civil Works, General Considerations for Design and Rehabilitation

DTIC Science & Technology

1993-08-01

34Weathering Steel Requires Proper Detailing," Chicago, IL. US Army Corps of Engineers. 1989. "Mechanical Properties and Corrosion Behavior of Stainless...types of corrosion and corro- sion protection are addressed. In Part X, authored by Dr. John Jaeger, vari- ous cases of distressed hydraulic steel ...guide in selecting a steel appropriate for a given application. Effects of alloying elements 8. Alloying elements are added to steel to effect

Galvanic corrosion behavior of orthodontic archwire alloys coupled to bracket alloys.

PubMed

Iijima, Masahiro; Endo, Kazuhiko; Yuasa, Toshihiro; Ohno, Hiroki; Hayashi, Kazuo; Kakizaki, Mitsugi; Mizoguchi, Itaru

2006-07-01

The purpose of this study was to provide a quantitative assessment of galvanic corrosion behavior of orthodontic archwire alloys coupled to orthodontic bracket alloys in 0.9% NaCl solution and to study the effect of surface area ratios. Two common bracket alloys, stainless steels and titanium, and four common wire alloys, nickel-titanium (NiTi) alloy, beta-titanium (beta-Ti) alloy, stainless steel, and cobalt-chromium-nickel alloy, were used. Three different area ratios, 1:1, 1:2.35, and 1:3.64, were used; two of them assumed that the multibracket appliances consists of 14 brackets and 0.016 inch of round archwire or 0.016 x 0.022 inch of rectangular archwire. The galvanic current was measured for 3 successive days using zero-impedance ammeter. When the NiTi alloy was coupled with Ti (1:1, 1:2.35, and 1:3.64 of the surface area ratio) or beta-Ti alloy was coupled with Ti (1:2.35 and 1:3.64 of the surface area ratio), Ti initially was the anode and corroded. However, the polarity reversed in 1 hour, resulting in corrosion of the NiTi or beta-Ti. The NiTi alloy coupled with SUS 304 or Ti exhibited a relatively large galvanic current density even after 72 hours. It is suggested that coupling SUS 304-NiTi and Ti-NiTi may remarkably accelerate the corrosion of NiTi alloy, which serves as the anode. The different anode-cathode area ratios used in this study had little effect on galvanic corrosion behavior.

Microstructure and properties of thermomechanically strengthened reinforcement bars: A comparative assessment of plain-carbon and low-alloy steel grades

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ray, A.; Mukerjee, D.; Sen, S.K.

1997-06-01

An extensive investigation has been carried out to study structure-property characteristics and corrosion behavior in three varieties of thermomechanically treated (TMT) reinforcement bars (rebars) produced in an integrated steel plant under the Steel Authority of India Limited. Three experimental steel heats--one of plain-carbon and two of low-alloy chemistry--were chosen for the study. Of the two low-alloy heats, one was copper-bearing and the other contained both copper and chromium for improved corrosion resistance. Hot-rolled bars for each specific chemistry were subjected to in-line thermomechanical treatment, where quenching parameters were altered to achieve different yield strength levels. All the TMT rebars, regardlessmore » of chemistry and strength level, exhibited a composite microstructure consisting of ferrite-pearlite at the core and tempered martensite at the rim. Although a tendency toward formation of Widmanstaetten ferrite was evident in bars of 500 and 550 MPa yield strength levels, no adverse effect on their strength and ductility was observed. From the standpoint of mechanical properties, the rebars not only conformed to minimum yield strength requirements, but also exhibited high elongation values (21 to 28%) and excellent bendability. Corrosion studies of both TMT and cold-twisted and deformed (CTD) rebars subjected to different laboratory tests indicated that corrosion resistance increased in this order: CTD, plain-carbon TMT, copper-bearing TMT, and copper/chromium-bearing TMT.« less

Effect of Heat Treatment on the Impact Toughness of `High-Chromium Cast Iron - Low Alloy Steel' Bimetal Components

NASA Astrophysics Data System (ADS)

Özdemir, Z.

2017-03-01

A bimetallic `low-alloy steel - high-chromium cast iron' composite obtained by successive sand casting is studied and shown to have good cohesion on the interface and no casting defects. The hardness and the impact toughness of the bimetal increase simultaneously. The microstructure is more homogeneous after diffusion annealing at 1040°C, rapid cooling, and 3-h tempering at 270°C.

Microstructure and Properties of Lap Joint Between Aluminum Alloy and Galvanized Steel by CMT

NASA Astrophysics Data System (ADS)

Niu, Song; Chen, Su; Dong, Honggang; Zhao, Dongsheng; Zhang, Xiaosheng; Guo, Xin; Wang, Guoqiang

2016-05-01

Lap joining of 1-mm-thick Novelist AC 170 PX aluminum alloy to 1.2-mm-thick ST06 Z galvanized steel sheets for automotive applications was conducted by cold metal transfer advanced welding process with ER4043 and ER4047 filler wires. Under the optimized welding parameters with ER4043 filler wire, the tensile shear strength of joint was 189 MPa, reaching 89% of the aluminum alloy base metal. Microstructure and elemental distribution were characterized by optical metalloscope and electron probe microanalysis. The lap joints with ER4043 filler wire had smaller wetting angle and longer bonded line length with better wettability than with ER4047 filler wire during welding with same parameters. The needle-like Al-Fe-Si intermetallic compounds (IMCs) were spalled into the weld and brought negative effect to the tensile strength of joints. With increasing welding current, the needle-like IMCs grew longer and spread further into the weld, which would deteriorate the tensile shear strength.

Atom probe tomography of intermetallic phases and interfaces formed in dissimilar joining between Al alloys and steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lemmens, B.

While Si additions to Al are widely used to reduce the thickness of the brittle intermetallic seam formed at the interface during joining of Al alloys to steel, the underlying mechanisms are not clarified yet. The developed approach for the site specific atom probe tomography analysis revealed Si enrichments at grain and phase boundaries between the θ (Fe{sub 4}Al{sub 13}) and η (Fe{sub 2}Al{sub 5}) phase, up to about ten times that of the concentration in Al. The increase in Si concentration could play an important role for the growth kinetics of the intermetallic phases formed for example in hot-dipmore » aluminizing of steel. - Highlights: •Si additions to Al reduce thickness of intermetallic seam in joining with steel. •Approach developed for the site specific APT analysis of the intermetallic seam •Si enrichment at grain and phase boundaries possibly affects growth of intermetallics.« less

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

NASA Astrophysics Data System (ADS)

Zhang, Zhenbo; Pantleon, Wolfgang

2017-07-01

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 systematically investigated by high-resolution transmission electron microscopy. The majority of oxide nanoparticles were identified to be orthorhombic YAlO3. During hot consolidation and extrusion, they develop a coherent interface and a near cuboid-on-cube orientation relationship with the ferrite matrix in the material. After annealing at 1200 °C for 1 h, however, the orientation relationship between the oxide nanoparticles and the matrix becomes arbitrary, and their interface mostly incoherent. Annealing at 1300 °C leads to considerable coarsening of oxide nanoparticles, and a new orientation relationship of pseudo-cube-on-cube between oxide nanoparticles and ferrite matrix develops. The reason for the developing interfaces and orientation relationships between oxide nanoparticles and ferrite matrix under different conditions is discussed.

Microstructure and properties of thermally sprayed Al-Sn-based alloys for plain bearing applications

NASA Astrophysics Data System (ADS)

Marrocco, T.; Driver, L. C.; Harris, S. J.; McCartney, D. G.

2006-12-01

Al-Sn plain bearings for automotive applications traditionally comprise a multilayer structure. Conventionally, bearing manufacturing involves casting the Al-Sn alloy and roll-bonding to a steel backing strip. Recently, high-velocity oxyfuel (HVOF) thermal spraying has been used as a novel alternative manufacturing route. The present project extends previous work on ternary Al-Sn-Cu alloys to quaternary systems, which contain specific additions for potentially enhanced properties. Two alloys were studied in detail, namely, Al-20wt.%Sn-1wt.%Cu-2wt.%Ni and Al-20wt.%Sn-1wt.%Cu-7wt.%Si. This article will describe the microstructural evolution of these alloys following HVOF spraying onto steel substrates and subsequent heat treatment. The microstructures of powders and coatings were investigated by scanning electron microscopy, and the phases were identified by x-ray diffraction. Coating microhardnesses were determined under both as-sprayed and heat-treated conditions, and by the differences related to the microstructures that developed. Finally, the wear behavior of the sprayed and heat-treated coatings in hot engine oil was measured using an industry standard test and was compared with that of previous work on a ternary alloy.

Synergistic Computational and Microstructural Design of Next- Generation High-Temperature Austenitic Stainless Steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karaman, Ibrahim; Arroyave, Raymundo

The purpose of this project was to: 1) study deformation twinning, its evolution, thermal stability, and the contribution on mechanical response of the new advanced stainless steels, especially at elevated temperatures; 2) study alumina-scale formation on the surface, as an alternative for conventional chromium oxide, that shows better oxidation resistance, through alloy design; and 3) design new generation of high temperature stainless steels that form alumina scale and have thermally stable nano-twins. The work involved few baseline alloys for investigating the twin formation under tensile loading, thermal stability of these twins, and the role of deformation twins on the mechanicalmore » response of the alloys. These baseline alloys included Hadfield Steel (Fe-13Mn-1C), 316, 316L and 316N stainless steels. Another baseline alloy was studied for alumina-scale formation investigations. Hadfield steel showed twinning but undesired second phases formed at higher temperatures. 316N stainless steel did not show signs of deformation twinning. Conventional 316 stainless steel demonstrated extensive deformation twinning at room temperature. Investigations on this alloy, both in single crystalline and polycrystalline forms, showed that deformation twins evolve in a hierarchical manner, consisting of micron–sized bundles of nano-twins. The width of nano-twins stays almost constant as the extent of strain increases, but the width and number of the bundles increase with increasing strain. A systematic thermomechanical cycling study showed that the twins were stable at temperatures as high as 900°C, after the dislocations are annealed out. Using such cycles, volume fraction of the thermally stable deformation twins were increased up to 40% in 316 stainless steel. Using computational thermodynamics and kinetics calculations, we designed two generations of advanced austenitic stainless steels. In the first generation, Alloy 1, which had been proposed as an alumina

Effects of combined silicon and molybdenum alloying on the size and evolution of microalloy precipitates in HSLA steels containing niobium and titanium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavlina, Erik J., E-mail: e.pavlina@deakin.edu.au; Van Tyne, C.J.; Speer, J.G.

2015-04-15

The effects of combined silicon and molybdenum alloying additions on microalloy precipitate formation in austenite after single- and double-step deformations below the austenite no-recrystallization temperature were examined in high-strength low-alloy (HSLA) steels microalloyed with titanium and niobium. The precipitation sequence in austenite was evaluated following an interrupted thermomechanical processing simulation using transmission electron microscopy. Large (~ 105 nm), cuboidal titanium-rich nitride precipitates showed no evolution in size during reheating and simulated thermomechanical processing. The average size and size distribution of these precipitates were also not affected by the combined silicon and molybdenum additions or by deformation. Relatively fine (< 20more » nm), irregular-shaped niobium-rich carbonitride precipitates formed in austenite during isothermal holding at 1173 K. Based upon analysis that incorporated precipitate growth and coarsening models, the combined silicon and molybdenum additions were considered to increase the diffusivity of niobium in austenite by over 30% and result in coarser precipitates at 1173 K compared to the lower alloyed steel. Deformation decreased the size of the niobium-rich carbonitride precipitates that formed in austenite. - Highlights: • We examine combined Si and Mo additions on microalloy precipitation in austenite. • Precipitate size tends to decrease with increasing deformation steps. • Combined Si and Mo alloying additions increase the diffusivity of Nb in austenite.« less

Thermally Stable Nanocrystalline Steel

NASA Astrophysics Data System (ADS)

Hulme-Smith, Christopher Neil; Ooi, Shgh Woei; Bhadeshia, Harshad K. D. H.

2017-10-01

Two novel nanocrystalline steels were designed to withstand elevated temperatures without catastrophic microstructural changes. In the most successful alloy, a large quantity of nickel was added to stabilize austenite and allow a reduction in the carbon content. A 50 kg cast of the novel alloy was produced and used to verify the formation of nanocrystalline bainite. Synchrotron X-ray diffractometry using in situ heating showed that austenite was able to survive more than 1 hour at 773 K (500 °C) and subsequent cooling to ambient temperature. This is the first reported nanocrystalline steel with high-temperature capability.

Effect of Sintering Atmosphere and Solution Treatment on Density, Microstructure and Tensile Properties of Duplex Stainless Steels Developed from Pre-alloyed Powders

NASA Astrophysics Data System (ADS)

Murali, Arun Prasad; Mahendran, Sudhahar; Ramajayam, Mariappan; Ganesan, Dharmalingam; Chinnaraj, Raj Kumar

2017-10-01

In this research, Powder Metallurgy (P/M) of Duplex Stainless Steels (DSS) of different compositions were prepared through pre-alloyed powders and elemental powders with and without addition of copper. The powder mix was developed by pot mill for 12 h to obtain the homogeneous mixture of pre-alloyed powder with elemental compositions. Cylindrical green compacts with the dimensions of 30 mm diameter and 12 mm height were compacted through universal testing machine at a pressure level of 560 ± 10 MPa. These green compacts were sintered at 1350 °C for 2 h in hydrogen and argon atmospheres. Some of the sintered stainless steel preforms were solution treated at 1050 °C followed by water quenching. The sintered as well as solution treated samples were analysed by metallography examination, Scanning Electron Microscopy and evaluation of mechanical properties. Ferrite content of sintered and solution treated DSS were measured by Fischer Ferritoscope. It is inferred that the hydrogen sintered DSS depicted better density (94% theoretical density) and tensile strength (695 MPa) than the argon sintered steels. Similarly the microstructure of solution treated DSS revealed existence of more volume of ferrite grains than its sintered condition. Solution treated hydrogen sintered DSS A (50 wt% 316L + 50 wt% 430L) exhibited higher tensile strength of 716 MPa and elongation of 17%, which are 10-13% increment than the sintered stainless steels.

Electrochemical and passive behaviour of tin alloyed ferritic stainless steel in concrete environment

NASA Astrophysics Data System (ADS)

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.

National Standard Catalog (Selected Pages).

DTIC Science & Technology

1987-09-11

Sodium thiosulphate - Iodine content method for measuring copper B 223.19-82 Chemical analysis of 63. 12.31 82.7.9 e.4. 1 steel iron and alloy...82.6.21 83.3.1 st ibium; Using burning iodine content to determine sulphur GB 3253.7-82 Chemical analysis of 82.6.21 83.3.1 stibium; Using 3, 3’ - two...Standard ID Standard Name __ _ Year Month Day Using iodine content to determinate stibium oxide GB 3254.2-82 Chemical analysis of 82.6.21 83.3.1

Alloy Design and Development of Cast Cr-W-V Ferritic Steels for Improved High-Temperature Strength for Power Generation Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klueh, R L; Maziasz, P J; Vitek, J M

2006-09-23

Economic and environmental concerns demand that the power-generation industry seek increased efficiency for gas turbines. Higher efficiency requires higher operating temperatures, with the objective temperature for the hottest sections of new systems {approx} 593 C, and increasing to {approx} 650 C. Because of their good thermal properties, Cr-Mo-V cast ferritic steels are currently used for components such as rotors, casings, pipes, etc., but new steels are required for the new operating conditions. The Oak Ridge National Laboratory (ORNL) has developed new wrought Cr-W-V steels with 3-9% Cr, 2-3% W, 0.25% V (compositions are in wt.%), and minor amounts of additionalmore » elements. These steels have the strength and toughness required for turbine applications. Since cast alloys are expected to behave differently from wrought material, work was pursued to develop new cast steels based on the ORNL wrought compositions. Nine casting test blocks with 3, 9, and 11% Cr were obtained. Eight were Cr-W-V-Ta-type steels based on the ORNL wrought steels; the ninth was COST CB2, a 9Cr-Mo-Co-V-Nb cast steel, which was the most promising cast steel developed in a European alloy-development program. The COST CB2 was used as a control to which the new compositions were compared, and this also provided a comparison between Cr-W-V-Ta and Cr-Mo-V-Nb compositions. Heat treatment studies were carried out on the nine castings to determine normalizing-and-tempering treatments. Microstructures were characterized by both optical and transmission electron microscopy (TEM). Tensile, impact, and creep tests were conducted. Test results on the first nine cast steel compositions indicated that properties of the 9Cr-Mo-Co-V-Nb composition of COST CB2 were better than those of the 3Cr-, 9Cr-, and 11Cr-W-V-Ta steels. Analysis of the results of this first iteration using computational thermodynamics raised the question of the effectiveness in cast steels of the Cr-W-V-Ta combination versus the

Characterization and cytotoxicity of ions released from stainless steel and nickel-titanium orthodontic alloys.

PubMed

Eliades, Theodore; Pratsinis, Harris; Kletsas, Dimitris; Eliades, George; Makou, Margarita

2004-01-01

The purpose of this study was to qualitatively and quantitatively characterize the substances released from orthodontic brackets and nickel-titanium wires and to comparatively assess the cytotoxicity of the ions released from these orthodontic alloys. Two full sets of stainless steel brackets of 20 brackets each (weight 2.1 g) and 2 groups of 0.018 x 0.025 Ni-Ti archwires of 10 wires each (weight 2.0 g) were immersed in 0.9% saline solution for a month. The immersion media were analyzed with inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and the ionic content was statistically analyzed with 1-way analysis of variance (ANOVA). Human periodontal ligament fibroblasts and gingival fibroblasts were exposed to various concentrations of the 2 immersion media; nickel chloride was used as a positive control for comparison purposes. The cytotoxic or cytostatic activity of the media was investigated with the MTT and the DNA synthesis assays. The results of the cytotoxicity assay were analyzed with 2-way ANOVA and the Tukey test with solution and concentration variants as discriminating variables (alpha=0.05). The results indicated no ionic release for the nickel-titanium alloy aging solution, whereas measurable nickel and traces of chromium were found in the stainless steel bracket-aging medium. Concentrations of the nickel chloride solution greater then 2 mM were found to reduce by more than 50% the viability and DNA synthesis of fibroblasts; however, neither orthodontic materials-derived media had any effect on the survival and DNA synthesis of either cells.

Oxidation of Slurry Aluminide Coatings on Cast Stainless Steel Alloy CF8C-Plus at 800oC in Water Vapor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haynes, James A; Armstrong, Beth L; Dryepondt, Sebastien N

A new, cast austenitic stainless steel, CF8C-Plus, has been developed for a wide range of high temperature applications, including diesel exhaust components, turbine casings and turbocharger housings. CF8C-Plus offers significant improvements in creep rupture life and creep rupture strength over standard CF8C steel. However, at higher temperatures and in more aggressive environments, such as those containing significant water vapor, an oxidation-resistant protective coating will be necessary. The oxidation behavior of alloys CF8C and CF8C-Plus with various aluminide coatings were compared at 800oC in air plus 10 vol% water vapor. Due to their affordability, slurry aluminides were the primary coating systemmore » of interest, although chemical vapor deposition (CVD) and pack cementation coatings were also compared. Additionally, a preliminary study of the low cycle fatigue behavior of aluminized CF8C-Plus was conducted at 800oC. Each type of coating provided substantial improvements in oxidation behavior, with simple slurry aluminides showing very good oxidation resistance after 4,000 h testing in water vapor. Preliminary low cycle fatigue results indicated that thicker aluminide coatings degraded high temperature fatigue properties of CF8C-Plus, whereas thinner coatings did not. Results suggest that appropriately designed slurry aluminide coatings are a viable option for economical, long-term oxidation protection of austenitic stainless steels in water vapor.« less

Heat-Resistant Alloys for Ordnance Materiel and Aircraft and Naval Engine Parts (N-102): Part 1 - Heat Resistant Alloys of the 21%Cr:9%Ni Type

DTIC Science & Technology

1945-06-29

10.555Ni Alloy 22 Sigma and Ferrite In 22.3#r:7.7*Ni Alloy 23 Ferrite Mosaic In 22.3#r:7.7#Ni Alloy 24 Precipitated Carbides In 21.2*Cr:8.7*Ni... ferritic steels and heat resistant cast irons are widely applied. Where plasticity is essential,steels must be used. The irons exhibit some...ductility above 900°F, but they are seldom able to survive sudden thermal or mechanical stresses that exceed their elastic strength. Ferritic steels, of

PHOTOCOPY OF STANDARD USDA/USFS PLAN FOR 13' X 13' STEEL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PHOTOCOPY OF STANDARD USDA/USFS PLAN FOR 13' X 13' STEEL LOOKOUT HOUSE (CAB); ELEVATIONS, SECTIONS, MISC. DETAILS; DATED 1961 - North Mountain Lookout, Stanislaus National Forest, Groveland, Tuolumne County, CA

Surface Alloying of SUS 321 Chromium-Nickel Steel by an Electron-Plasma Process

NASA Astrophysics Data System (ADS)

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.

Effect of solute concentration on grain boundary migration with segregation in stainless steel and model alloys

NASA Astrophysics Data System (ADS)

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.

Sporicidal efficacy of thermal-sprayed copper alloy coating.

PubMed

Shafaghi, Romina; Mostaghimi, Javad; Pershin, Valerian; Ringuette, Maurice

2017-05-01

Approximately 200 000 Canadians acquire healthcare-associated bacterial infections each year and several-fold more acquire food-borne bacterial illnesses. Bacterial spores are particularly problematic because they can survive on surfaces for several months. Owing to its sporicidal activity, copper alloy sheet metal is sometimes used in hospital settings, but its widespread use is limited by cost and incompatibility with complex furniture and instrument designs and topographies. A potential alternative is the use of thermal spray technology to coat surfaces with copper alloys. We compared the sporicidal activity of thermally sprayed copper alloy on stainless steel with that of copper alloy sheet metal against Bacillus subtilis spores. Spores remained intact for at least 1 week on uncoated stainless steel, whereas spore fragmentation was initiated within 2 h of exposure to either copper surface. Less than 15% of spores were viable 2 h after exposure to either copper surface, as compared with stainless steel. By day 7, only degraded spores and petal-like nanoflowers were present on the copper surfaces. Nanoflowers, which are laminar arrangements of thin crystal sheets composed of carbon - copper phosphate, appeared to be derived from the degraded spores. Altogether, these results indicate that a thermal-sprayed copper alloy coating on stainless steel provides sporicidal activity similar to that afforded by copper alloy sheet metal.

High yttria ferritic ODS steels through powder forging

NASA Astrophysics Data System (ADS)

Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

2017-05-01

Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y2O3 (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility.

TEM and HRTEM study of oxide particles in an Al-alloyed high-Cr oxide dispersion strengthened ferritic steel with Hf addition

NASA Astrophysics Data System (ADS)

Dou, Peng; Kimura, Akihiko; Kasada, Ryuta; Okuda, Takanari; Inoue, Masaki; Ukai, Shigeharu; Ohnuki, Somei; Fujisawa, Toshiharu; Abe, Fujio; Jiang, Shan; Yang, Zhigang

2017-03-01

The nanoparticles in an Al-alloyed high-Cr oxide dispersion strengthened (ODS) ferritic steel with Hf addition, i.e., SOC-16 (Fe-15Cr-2W-0.1Ti-4Al-0.62Hf-0.35Y2O3), have been examined by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Relative to an Al-alloyed high-Cr ODS ferritic steel without Hf addition, i.e., SOC-9 (Fe-15.5Cr-2W-0.1Ti-4Al-0.35Y2O3), the dispersion morphology and coherency of the oxide nanoparticles in SOC-16 were significantly improved. Almost all the small nanoparticles (diameter <10 nm) in SOC-16 were found to be consistent with cubic Y2Hf2O7 oxides with the anion-deficient fluorite structure and coherent with the bcc steel matrix. The larger particles (diameter >10 nm) were also mainly identified as cubic Y2Hf2O7 oxides with the anion-deficient fluorite structure. The results presented here are compared with those of SOC-9 with a brief discussion of the underlying mechanisms of the unusual thermal and irradiation stabilities of the oxides as well as the superior strength, excellent irradiation tolerance and extraordinary corrosion resistance of SOC-16.

Study on the Effect of Secondary Banded Structure on the Fatigue Property of Non-Quenched and Tempered Micro Alloyed Steel

NASA Astrophysics Data System (ADS)

Yajie, Cheng; Qingliang, Liao; Yue, Zhang

Due to composition segregation and cooling speed, streamline or banded structure were often obtained in the thermal forming parts along the direction of parts forming. Generally speaking, banded structure doesn't decrease the longitudinal mechanical properties, so the secondary banded structure can't get enough attention. The effect of secondary banded structure on the fatigue properties of micro alloyed DG20Mn and 35CrMo steel was investigated using the axial tensile fatigue test of stress ratio of 0.1. The result shows that secondary banded structure was obtained in the center of the steel parts, because of the composition segregation and the lower cooling rate in center part of steel. Secondary banded structure has no significant effect on axial tensile properties of both DG20Mn and 35CrMo, but decreases the axial tensile fatigue performance of DG20Mn steel. This study suggests that under the high cyclic tensile stress, multi-source damage cracks in steel initiated by large strain of pearlite of secondary banded structure, which is larger than damage strain, is the major factor of the decrease of fatigue life of steel.

Quantification of oxide particle composition in model oxide dispersion strengthened steel alloys.

PubMed

London, A J; Lozano-Perez, S; Moody, M P; Amirthapandian, S; Panigrahi, B K; Sundar, C S; Grovenor, C R M

2015-12-01

Oxide dispersion strengthened ferritic steels (ODS) are being considered for structural components of future designs of fission and fusion reactors because of their impressive high-temperature mechanical properties and resistance to radiation damage, both of which arise from the nanoscale oxide particles they contain. Because of the critical importance of these nanoscale phases, significant research activity has been dedicated to analysing their precise size, shape and composition (Odette et al., Annu. Rev. Mater. Res. 38 (2008) 471-503 [1]; Miller et al., Mater. Sci. Technol. 29(10) (2013) 1174-1178 [2]). As part of a project to develop new fuel cladding alloys in India, model ODS alloys have been produced with the compositions, Fe-0.3Y2O3, Fe-0.2Ti-0.3Y2O3 and Fe-14Cr-0.2Ti-0.3Y2O3. The oxide particles in these three model alloys have been studied by APT in their as-received state and following ion irradiation (as a proxy for neutron irradiation) at various temperatures. In order to adequately quantify the composition of the oxide clusters, several difficulties must be managed, including issues relating to the chemical identification (ranging and variable peak-overlaps); trajectory aberrations and chemical structure; and particle sizing. This paper presents how these issues can be addressed by the application of bespoke data analysis tools and correlative microscopy. A discussion follows concerning the achievable precision in these measurements, with reference to the fundamental limiting factors. Copyright © 2015 Elsevier B.V. All rights reserved.

Performance Steel Castings

DTIC Science & Technology

2012-09-30

Development of Sand Properties 103 Advanced Modeling Dataset.. 105 High Strength Low Alloy (HSLA) Steels 107 Steel Casting and Engineering Support...to achieve the performance goals required for new systems. The dramatic reduction in weight and increase in capability will require high performance...for improved weapon system reliability. SFSA developed innovative casting design and manufacturing processes for high performance parts. SFSA is

Steeling and Resilience in Art Education

ERIC Educational Resources Information Center

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…

Comparative study on the corrosion behavior of the cold rolled and hot rolled low-alloy steels containing copper and antimony in flue gas desulfurization environment

NASA Astrophysics Data System (ADS)

Park, S. A.; Kim, J. G.; He, Y. S.; Shin, K. S.; Yoon, J. B.

2014-12-01

The correlation between the corrosion and microstructual characteristics of cold rolled and hot rolled low-alloy steels containing copper and antimony was established. The corrosion behavior of the specimens used in flue gas desulfurization systems was examined by electrochemical and weight loss measurements in an aggressive solution of 16.9 vol % H2SO4 + 0.35 vol % HCl at 60°C, pH 0.3. It has been shown that the corrosion rate of hot rolled steel is lower than that of cold rolled steel. The corrosion rate of cold rolled steel was increased by grain refinement, inclusion formation, and preferred grain orientation.

Fe-Al-Mn-C lightweight structural alloys: a review on the microstructures and mechanical properties.

PubMed

Kim, Hansoo; Suh, Dong-Woo; Kim, Nack J

2013-02-01

Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe-Al-Mn-C alloys were patented in 1950s for replacement of nickel or chromium in corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structural material. Strengthening without loss of ductility has been a triumph in steel research, but lowering the density of steel by mixing with light elements will be another prospect that may support the competitiveness against emerging alternatives such as magnesium alloys. In this paper, we review recent studies on lightweight steels, emphasizing the concept of alloy design for microstructures and mechanical properties. The influence of alloying elements on the phase constituents, mechanical properties and the change of density is critically reviewed. Deformation mechanisms of various lightweight steels are discussed as well. This paper provides a reason why the success of lightweight steels is strongly dependent on scientific achievements even though alloy development is closely related to industrial applications. Finally, we summarize some of the main directions for future investigations necessary for vitalizing this field of interest.

Fe–Al–Mn–C lightweight structural alloys: a review on the microstructures and mechanical properties

PubMed Central

Kim, Hansoo; Suh, Dong-Woo; Kim, Nack J

2013-01-01

Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe–Al–Mn–C alloys were patented in 1950s for replacement of nickel or chromium in corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structural material. Strengthening without loss of ductility has been a triumph in steel research, but lowering the density of steel by mixing with light elements will be another prospect that may support the competitiveness against emerging alternatives such as magnesium alloys. In this paper, we review recent studies on lightweight steels, emphasizing the concept of alloy design for microstructures and mechanical properties. The influence of alloying elements on the phase constituents, mechanical properties and the change of density is critically reviewed. Deformation mechanisms of various lightweight steels are discussed as well. This paper provides a reason why the success of lightweight steels is strongly dependent on scientific achievements even though alloy development is closely related to industrial applications. Finally, we summarize some of the main directions for future investigations necessary for vitalizing this field of interest. PMID:27877553

Low activation ferritic alloys

DOEpatents

Gelles, David S.; Ghoniem, Nasr M.; Powell, Roger W.

1986-01-01

Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

Low activation ferritic alloys

DOEpatents

Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.

1985-02-07

Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

Superplasticity in a lean Fe-Mn-Al steel.

PubMed

Han, Jeongho; Kang, Seok-Hyeon; Lee, Seung-Joon; Kawasaki, Megumi; Lee, Han-Joo; Ponge, Dirk; Raabe, Dierk; Lee, Young-Kook

2017-09-29

Superplastic alloys exhibit extremely high ductility (>300%) without cracks when tensile-strained at temperatures above half of their melting point. Superplasticity, which resembles the flow behavior of honey, is caused by grain boundary sliding in metals. Although several non-ferrous and ferrous superplastic alloys are reported, their practical applications are limited due to high material cost, low strength after forming, high deformation temperature, and complicated fabrication process. Here we introduce a new compositionally lean (Fe-6.6Mn-2.3Al, wt.%) superplastic medium Mn steel that resolves these limitations. The medium Mn steel is characterized by ultrafine grains, low material costs, simple fabrication, i.e., conventional hot and cold rolling, low deformation temperature (ca. 650 °C) and superior ductility above 1300% at 850 °C. We suggest that this ultrafine-grained medium Mn steel may accelerate the commercialization of superplastic ferrous alloys.Research in new alloy compositions and treatments may allow the increased strength of mass-produced, intricately shaped parts. Here authors introduce a superplastic medium manganese steel which has an inexpensive lean chemical composition and which is suited for conventional manufacturing processes.

A comprehensive review on cold work of AISI D2 tool steel

NASA Astrophysics Data System (ADS)

Abdul Rahim, Mohd Aidil Shah bin; Minhat, Mohamad bin; Hussein, Nur Izan Syahriah Binti; Salleh, Mohd Shukor bin

2017-11-01

As a common material in mould and die application, AISI D2 cold work tool steel has proven to be a promising chosen material in the industries. However, challenges remain in using AISI D2 through a modified version with a considerable progress having been made in recent years. This paper provides a critical review of the original as-cast AISI D2 cold work tool steel up to the modified version. The main purpose is to develop an understanding of current modified tool steel trend; the machinability of AISI D2 (drilling, milling, turning, grinding and EDM/WEDM; and the microstructure evolution and mechanical properties of these cold work tool steels due to the presence of alloy materials in the steel matrix. The doping of rare earth alloy element, new steel fabrication processes, significant process parameter in machinability and surface treatment shows that there have been few empirical investigations into these cold work tool steel alloys. This study has discovered that cold work tool steel will remain to be explored in order to survive in the steel industries.

24 CFR 200.949 - Building product standards and certification program for exterior insulated steel door systems.

Code of Federal Regulations, 2012 CFR

2012-04-01

... certification program for exterior insulated steel door systems. 200.949 Section 200.949 Housing and Urban... program for exterior insulated steel door systems. (a) Applicable standards. (1) All Exterior Insulated Steel Door Systems shall be designed, manufactured, and tested in compliance with the following...

24 CFR 200.949 - Building product standards and certification program for exterior insulated steel door systems.

Code of Federal Regulations, 2013 CFR

2013-04-01

... certification program for exterior insulated steel door systems. 200.949 Section 200.949 Housing and Urban... program for exterior insulated steel door systems. (a) Applicable standards. (1) All Exterior Insulated Steel Door Systems shall be designed, manufactured, and tested in compliance with the following...

Fracture Behavior of Ultra-Low-Carbon Steel Plate and Heat-Affected-Zone.

DTIC Science & Technology

1990-12-01

ferrite . This effect on the transformation kinetics of steel is shown in Fig. 2. This alloying addition, however, has experienced...V-notch ITT of -76’F (-600C). The design philo.ophy used for this alloy required that the steel be low carbon with a nearly 100% acicular ferrite ...line pipe fitting steel by International Nickel Company and was called IN 787. It is a low carbon-manganese steel strengthened with a fine precipitate

Multiphase Microstructure in a Metastability-Assisted Medium Carbon Alloy Steel

NASA Astrophysics Data System (ADS)

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.

Tungsten solution kinetics and amorphization of nickel in mechanically alloyed Ni-W alloys