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1
Lad’yanov, V. I., G. A. Dorofeev, E. V. Kuz’minykh, V. A. Karev, and A. N. Lubnin. "ALUMINOBAROTHERMIC SYNTHESIS OF HIGH-NITROGEN STEEL." Izvestiya. Ferrous Metallurgy 62, no. 2 (March 30, 2019): 154–62. http://dx.doi.org/10.17073/0368-0797-2019-2-154-162.
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High-nitrogen austenitic steels are promising materials, combining high strength, plasticity and corrosion resistance properties. However, to produce high-nitrogen steel by conventional metallurgical methods under high nitrogen pressure, powerful and complex metallurgical equipment is required. From energy-saving viewpoint, an alternative and simpler method for producing high-nitrogen steels can be aluminothermy (reduction of metal oxides by metallic aluminum) under nitrogen pressure. Thermodynamic modeling of aluminothermic reactions in a nitrogen atmosphere was carried out by the authors. Aluminothermy under nitrogen pressure was used to produce high-nitrogen nickel-free Cr – N and Cr – Mn – N stainless steels with a nitrogen content of about 1 %. Microstructure (X-ray diffraction, metallography and transmission electron microscopy techniques) and mechanical properties were examined. Thermodynamic analysis has shown that the aluminothermic reduction reactions do not go to the end. The most important parameter of the synthesis is the ratio of Al and oxygen in the charge, the correct choice of which provides a compromise between completeness of oxides reduction, content of aluminum and oxygen in steel (the degree of deoxidation), and its contamination with aluminum nitride. Cr – N steel ingots in the cast state had the structure of nitrogen perlite (ferrite-nitride mixture), and Cr – Mn – N steel – ferrite-austenite structure with attributes of austenite discontinuous decomposition with Cr2 N precipitations. Quenching resulted in complete austenization of both steels. The compliance of the austenite lattice parameter obtained from the diffractograms for quenched Cr – Mn – N steel with the parameter predicted from the known concentration dependence for Cr – Mn – N austenitic steels indicated that all alloying elements (including nitrogen) were dissolved in austenite during aging at quenching temperature and fixed in the solid solution by quenching. Study of the mechanical properties of quenched Cr – Mn – N steel has shown a combination of high strength and ductility. It is concluded that by the aluminothermic method a high-nitrogen steel can be obtained, which, by mechanical properties, is not inferior to industrial steel – analog manufacted by electroslag remelting under nitrogen pressure.
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Lucaci, Mariana, Magdalena Lungu, Eugeniu Vasile, Virgil Marinescu, Dorinel Talpeanu, Gabriela Sbarcea, Nicolae Stancu, et al. "Advanced High Strength Steel (AHSS) Alloys." Journal of the American Romanian Academy of Arts and Sciences 1, no. 1 (August 15, 2017): 46–50. http://dx.doi.org/10.14510/araj.2017.4122.
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Bui, Anh-Hoa, and Hoang Le. "STRENGTH AND MICROSTRUCTURE OF COLD-ROLLED IF STEEL." Acta Metallurgica Slovaca 22, no. 1 (March 29, 2016): 35. http://dx.doi.org/10.12776/ams.v22i1.690.
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<p>With the emerge of vacuum technology, it is possible to produce ultra low carbon (ULC) steels with carbon content of less than 0.005 %mass which is called interstitial free (IF) steels. In this study, strength and microstructure of IF steel after cold-rolling have been determined. The initial steel plates were cold-rolled using two different cold reductions (CR) as 80 and 90% in total, thereafter the steel sheets were cut into specimens for tensile test and optical microscopy. Ultimate tensile strength (UTS) of the cold-rolled steel was high (650¸807 MPa), but the elongation (EL) was low (3.5¸5.3%). Meanwhile, UTS of the annealed steels was decreased to 290 MPa when soaking temperature was 800<sup>o</sup>C because of stress relief and recrystallization. It was concluded that higher CR (more severe deformation) increased the strength but decreased the ductility of the IF steels. In consistence with micrograph of the steels, X-ray diffraction (XRD) results showed that microstructure of the cold-rolled and annealed IF steels was only ferrite. Textures, one of the most important factors affecting the recrystallization, were found in cold-rolled steels.</p>
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Hu, Min. "Study on Welding Technology of Low Alloy High Strength Steel." Key Engineering Materials 814 (July 2019): 242–47. http://dx.doi.org/10.4028/www.scientific.net/kem.814.242.
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WELDOX series steels are commonly used structural steels. The effects of welding voltage, welding current and arc height on penetration and weld width of WELDOX960 steel sheet were studied. The mechanical properties and microstructure of WELDOX960E high strength steel welded joints were study by tensile, bending, impact, hardness and metallographic analysis.
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Song, Quan Ming, and David Wert. "State of the Art Stainless Steel Provides Improved Properties for Widely Varying Applications." Advanced Materials Research 413 (December 2011): 341–46. http://dx.doi.org/10.4028/www.scientific.net/amr.413.341.
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Carpenter Technology Corporation’s Custom 465® stainless steel is a state-of-the-art alloy which has seen its applications expanding at a rapid rate. This alloy is a premium double vacuum melted (VIM/VAR) martensitic precipitation hardening stainless steel that offers an excellent combination of strength, toughness, and corrosion resistance. With its exceptional properties, design engineers have specified the alloy for high-performance components in various industries, such as aerospace, industrial, energy, consumer and medical. The high strength, greater than 250 ksi (1722 MPa) typical, and toughness of the alloy have allowed Custom 465 stainless to be used as a high-strength upgrade to conventional PH stainless steels such as 13-8 and 17-4. The addition of corrosion resistance to the high strength and toughness properties has allowed the alloy to be used as a stainless alternative to non-stainless steels such as AISI 4340 and 300M. This paper will compare mechanical and corrosion resistance properties of Custom 465 stainless steel to those of other PH stainless steels such as 17-4, 15-5, and 13-8, as well as to those of other aerospace alloys such as 300M and AerMet® 100 alloy. In addition, examples of the varied uses of the alloy will be provided, these examples will highlight the benefits obtained by the use of Custom 465 stainless steel over the previous alloys of choice for the applications.
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Montemarano, T. W., B. P. Sack, J. P. Gudas, M. G. Vassilaros, and H. H. Vanderveldt. "High Strength Low Alloy Steels in Naval Construction." Journal of Ship Production 2, no. 03 (August 1, 1986): 145–62. http://dx.doi.org/10.5957/jsp.1986.2.3.145.
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The Naval Sea Systems Command has recently certified a lower-cost alternative steel to the HY-80 steel presently used in construction of naval surface ships. This alternative steel is based on the commercial development of high strength low alloy (HSLA) steels originally directed to the offshore oil exploration platform and gas line transmission industries. The certification is a result of an ongoing research and development program begun in 1980. This paper addresses several aspects of the HSLA steel development effort, including a discussion of the properties and metallurgy of this steel, and the cost savings which are achievable. Finally, the status of the current and planned Navy HSLA usage and the R&D program is described.
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Zhang, Mei, Jun Zhang, Yu Xiang Ning, Tao Wang, and Zi Wan. "Springback Behavior of Advanced High Strength Steel (AHSS) CP800." Advanced Materials Research 820 (September 2013): 45–49. http://dx.doi.org/10.4028/www.scientific.net/amr.820.45.
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800MPa grade Advanced High Strength Steels (AHSS), Complex Phase steel CP800, containing microalloying elements, are chosen to test the stamping properties in different test conditions and compared with traditional high strength low alloy (HSLA) steels HSLA S700MC. Tensile test, and HAT shape stamping test are taken to investigate the properties of the materials. Test results indicate that the studied 800MPa grade AHSS shows a better strength ductility balance compared with the reference HSLA steels. Under the same HAT shape springback stamping condition, HSLA steels S700MC always show the largest springback deformation among the investigated steels. While springback angles of all the AHSS studied are markedly smaller than that of steel S700MC. Among the 3 kinds of AHSS researched, CP800T always show the largest springback deformation. Domestic steel CP800 and imported CP800S show much smaller springback deformation respectively. In BHF of 100KN condition, springback deformation of 3 kinds of AHSS reaches the top value among all the BHF conditions. However, steel CP800 indicates an outstanding springback restrain trend in blank holding force (BHF) further increasing attempt. Thus, springback behavior can be restricted obviously by using a larger blank holding force (BHF) in steel CP800 stamping cases.
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Kazior, Jan, Aneta Szewczyk-Nykiel, Tadeusz Pieczonka, Marek Hebda, and Marek Nykiel. "Properties of Precipitation Hardening 17-4 PH Stainless Steel Manufactured by Powder Metallurgy Technology." Advanced Materials Research 811 (September 2013): 87–92. http://dx.doi.org/10.4028/www.scientific.net/amr.811.87.
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Alloys from austenitic and ferritic stainless steel found to be satisfactory for a great many applications. However, for applications that require higher levels of strength and hardness from the martensitic grades are frequently specified. Martensitic stainless steels offer significantly higher strengths but have to low ductility. For this reason for application where high levels of strength and a moderate ductility is required, the precipitation strengthened stainless steels are often considered. One of the most popular alloy of this kind of stainless steel is 17-4 PH. The aim of the present paper was to examined the influence the process parameters in conventional powder metallurgy processing on the mechanical properties of the 17-4 PH alloy in both as-sintered and heat treated conditions. In was found that temperature of aged is a very sensitive parameter for obtained high strength and acceptable ductility.
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Rogachev, S. O., A. Ya Stomakhin, S. A. Nikulin, M. V. Kadach, and V. M. Khatkevich. "STRUCTURE AND MECHANICAL PROPERTIES OF AUSTENITIC Cr – Ni – Ti STEELS AFTER HIGH-TEMPERATURE NITRIDING." Izvestiya. Ferrous Metallurgy 62, no. 5 (June 19, 2019): 366–73. http://dx.doi.org/10.17073/0368-0797-2019-5-366-373.
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Alloying of corrosion-resistant austenitic steels with nitrogen is widely used in production to stabilize austenite and to improve the strength and other properties of the metal. The possibility of alloying titanium-containing steels with nitrogen by introducing nitrogen into the melt is not possible, as it causes formation of the coarse defects in steel during casting and solidification of the metal (twisting of the peel, large nitride inclusions, accumulations of nitrides, etc.). The method of high-temperature gas nitriding can be alternative to liquid-phase nitriding for alloying austenitic titanium-containing chromium-nickel steels with nitrogen in order to increase their strength properties. In this work, we investigated the possibility of increasing the strength characteristics of thin-sheet austenitic corrosion-resistant Cr – Ni – Ti (Kh18N12T type) steel, containing 1.5 % and 3 % of titanium, through the use of solid-phase high-temperature nitriding. The nitriding was carried out at a temperature of 1000 – 1100 °С in an atmosphere of pure nitrogen for 5 or 8 hours. The average mass fraction of nitrogen in the samples after nitriding for 5 hours was 0.6 % and 0.7 % for the steels with 1.5 and 3 % of titanium, respectively, and after nitriding for 8 hours – 0.8 % and 0.9 %. It was shown that high-temperature nitriding followed by annealing provides a significant (by 2 – 3 times) increase in the metal strength characteristics compared with the state before nitriding, but reduces the ductility. Ductility of the steel is restored during final processing. For Kh18N12Т type steel with 1.5 % of titanium, an increase in the yield strength is obtained – by 3.3 times (from 180 to 600 MPa), strength – by 1.8 times (from 540 to 970 MPa), with a relative elongation of 28 %. An additional increase in strength properties was not found for the steel with 3 % titanium. The obtained results show the possibility of obtaining thin-sheet titanium-containing high-nitrogen steel (or products from it, for example, thin-walled pipes) by applying solid-phase high-temperature nitriding.
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Swindeman, R. W., and M. Gold. "Developments in Ferrous Alloy Technology for High-Temperature Service." Journal of Pressure Vessel Technology 113, no. 2 (May 1, 1991): 133–40. http://dx.doi.org/10.1115/1.2928737.
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Developments during the past twenty-five years are outlined for the technology of ferrous alloys needed in elevated temperature service. These developments include new alloys with improved strength and corrosion resistance for use in nuclear, fossil, and petrochemical applications. Specific groups of alloys that are addressed include vanadium-modified low alloy steels, 9Cr-1Mo-V steel, niobium-modified lean stainless steels, and high chrome-nickel iron alloys. A brief description of coating and claddings for improved corrosion resistance is also provided.
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Lu, Qi, Wei Xu, and Sybrand van der Zwaag. "A Material Genomic Design of Advanced High Performance, Non-Corroding Steels for Ambient and High Temperature Applications." Materials Science Forum 783-786 (May 2014): 1201–6. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.1201.
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This work presents an artificial intelligence based design of a series of novel advanced high performance steels for ambient and high temperature applications, following the principle of the materials genome initiative, using an integrated thermodynamics/kinetics based model in combination with a genetic algorithm optimization routine. Novel steel compositions and associated key heat treatment parameters are designed both for applications at the room temperature (ultra-high strength maraging stainless steel) and at high temperatures (ferritic, martensitic and austenitic creep resistant steels). The strength of existing high end alloys of aforementioned four types are calculated according to the corresponding design criteria. The model validation studies suggest that the newly designed alloys have great potential in outperforming existing grades.
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Jena, B. K., N. Gupta, B. Singh, and G. S. Ahoo. "Mechanical properties of low alloy high phosphorus weathering steel." Journal of Mining and Metallurgy, Section B: Metallurgy 51, no. 1 (2015): 81–87. http://dx.doi.org/10.2298/jmmb140120005j.
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Mechanical behaviour of two low alloy steels (G11 and G12) was studied with respect to different phosphorus contents. Tensile strength and yield strength increased while percentage elongation at fracture decreased on increasing phosphorus content. The SEM and light optical photomicrograph of low phosphorus steel (G11) revealed ferrite and pearlite microstructure. On increasing phosphorus content from 0.25 wt.% to 0.42 wt.%, the morphology of grain changed from equiaxed shape to pan-cake shape and grain size also increased. The Charpy V notch (CVN) impact energy of G11 and G12 steel at room temperature was 32 J and 4 J respectively and their fractographs revealed brittle rupture with cleavage facets for both the steels. However, the fractograph of G11 steel after tensile test exhibited ductile mode of fracture with conical equiaxed dimple while that of G12 steel containing 0.42 wt. % P exhibited transgranular cleavage fracture. Based on this study, G11 steel containing 0.25 wt. % P could be explored as a candidate material for weathering application purpose where the 20?C toughness requirement is 27 J as per CSN EN10025-2:2004 specification.
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Zhang, Mei, Yu Xiang Ning, Jun Zhang, Zi Wan, and Tao Wang. "Forming Performance of 800MPa Grade Advanced High Strength Steels." Applied Mechanics and Materials 455 (November 2013): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amm.455.173.
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800MPa grade Advanced High Strength Steels (AHSS), including Complex Phase steel CP800 and Ferrite-Bainite steel FB800, were chosen to test the forming performance in different test conditions and compared with the reference traditional high strength low alloy (HSLA) steels HR700LA. Tensile test, hole expansion (HE) test, and HAT shape stamping test were taken to investigate the forming performance of the materials. Test results indicated that the studied 800MPa grade AHSS showed a better strength ductility balance compared with the reference steel. Among all the steels researched, FB800 showed the best hole expansion ratio (HER), and CP800 the worst. Springback angles of AHSS after HAT shape stamping tests were markedly smaller than those of HR700LA steels, though the springback angles of HR700LA decreased continuously with blank holding force (BHF) increasing. Steel FB800, CP800S and CP800B had much better shape stability compared with steels HR700LA. AHSS showed much smaller springback behavior under the same stamping condition, especially for steels CP800-B, FB800-2 and FB800-1. When increasing the BHF to 100KN, AHSS showed the largest springback deformation. Among the three kinds of CP800 steels researched, steel CP800-B indicated outstanding springback restrain trend in BHF further increasing attempt. So, springback behavior could be restricted obviously by using a larger BHF in AHSS CP800B forming operations.
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Bastidas, David M., Jacob Ress, Juan Bosch, and Ulises Martin. "Corrosion Mechanisms of High-Mn Twinning-Induced Plasticity (TWIP) Steels: A Critical Review." Metals 11, no. 2 (February 7, 2021): 287. http://dx.doi.org/10.3390/met11020287.
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Twinning-induced plasticity (TWIP) steels have higher strength and ductility than conventional steels. Deformation mechanisms producing twins that prevent gliding and stacking of dislocations cause a higher ductility than that of steel grades with the same strength. TWIP steels are considered to be within the new generation of advanced high-strength steels (AHSS). However, some aspects, such as the corrosion resistance and performance in service of TWIP steel materials, need more research. Application of TWIP steels in the automotive industry requires a proper investigation of corrosion behavior and corrosion mechanisms, which would indicate the optimum degree of protection and the possible decrease in costs. In general, Fe−Mn-based TWIP steel alloys can passivate in oxidizing acid, neutral, and basic solutions, however they cannot passivate in reducing acid or active chloride solutions. TWIP steels have become as a potential material of interest for automotive applications due to their effectiveness, impact resistance, and negligible harm to the environment. The mechanical and corrosion performance of TWIP steels is subjected to the manufacturing and processing steps, like forging and casting, elemental composition, and thermo-mechanical treatment. Corrosion of TWIP steels caused by both intrinsic and extrinsic factors has posed a serious problem for their use. Passivity breakdown caused by pitting, and galvanic corrosion due to phase segregation are widely described and their critical mechanisms examined. Numerous studies have been performed to study corrosion behavior and passivation of TWIP steel. Despite the large number of articles on corrosion, few comprehensive reports have been published on this topic. The current trend for development of corrosion resistance TWIP steel is thoroughly studied and represented, showing the key mechanisms and factors influencing corrosion processes, and its consequences on TWIP steel. In addition, suggestions for future works and gaps in the literature are considered.
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Efthymiadis, Panos, and Khalid Nor. "Laser Welding Dissimilar High-Strength Steel Alloys with Complex Geometries." Metals 8, no. 10 (October 3, 2018): 792. http://dx.doi.org/10.3390/met8100792.
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Laser welding of dissimilar high-strength steels was performed in this study for two different geometries, flat and circular samples with material thicknesses of 5 and 8 mm. The material combinations were a low carbon to a medium or high carbon steel. Three different welding systems were employed: a Nd:YAG, a CO2 and a fiber laser. The process stability was evaluated for all the experiments. The resulting full penetration welds were inspected for their surface quality at the top and bottom of the specimens. Cross sections were taken to investigate the resulting microstructures and the metallurgical defects of the welds, such as cracks and pores. Significant hardening occurred in the weld region and the highest hardness values occurred in the Heat Affected Zone (HAZ) of the high carbon steel. The occurrence of weld defects depends strongly on the component geometry. The resulting microstructures within the weld were also predicted using neural network-simulated Continuous Cooling Transformation (CCT) diagrams and predicted the occurrence of a mixture of microstructures, such as bainite, martensite and pearlite, depending on the material chemistry. The thermal fields were measured with thermocouples and revealed the strong influence of component geometry on the cooling rate which in term defines the microstructures forming in the weld and the occurring hardness.
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Yang, Guanghui, and Jin-Kyung Kim. "An Overview of High Yield Strength Twinning-Induced Plasticity Steels." Metals 11, no. 1 (January 10, 2021): 124. http://dx.doi.org/10.3390/met11010124.
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Twinning-induced plasticity (TWIP) steel is a second-generation advanced high strength steel grade developed for automotive applications. TWIP steels exhibit an excellent combination of strength and ductility, mainly originating from the activation of deformation twinning. However, TWIP steels generally exhibit a relatively low yield strength (YS), which limits their practical applications. Thus, developing high YS TWIP steels without ductility loss is essential to increase their industrial applications. The present work summarizes and discusses the recent progress in improving the YS of TWIP steels, in terms of precipitation strengthening, solid solution strengthening, thermomechanical processing, and novel processes. Novel processes involving sub-boundary strengthening, multi-phase structure, and gradient structure as well as the control of thermomechanical processing (recovery annealing and warm rolling) and precipitation strengthening were found to result in an excellent combination of YS and total elongation.
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Cho, Lawrence, Yuran Kong, John G. Speer, and Kip O. Findley. "Hydrogen Embrittlement of Medium Mn Steels." Metals 11, no. 2 (February 20, 2021): 358. http://dx.doi.org/10.3390/met11020358.
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Recent research efforts to develop advanced–/ultrahigh–strength medium-Mn steels have led to the development of a variety of alloying concepts, thermo-mechanical processing routes, and microstructural variants for these steel grades. However, certain grades of advanced–/ultrahigh–strength steels (A/UHSS) are known to be highly susceptible to hydrogen embrittlement, due to their high strength levels. Hydrogen embrittlement characteristics of medium–Mn steels are less understood compared to other classes of A/UHSS, such as high Mn twinning–induced plasticity steel, because of the relatively short history of the development of this steel class and the complex nature of multiphase, fine-grained microstructures that are present in medium–Mn steels. The motivation of this paper is to review the current understanding of the hydrogen embrittlement characteristics of medium or intermediate Mn (4 to 15 wt pct) multiphase steels and to address various alloying and processing strategies that are available to enhance the hydrogen-resistance of these steel grades.
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Chandra-ambhorn, Somrerk, Shigenari Hayashi, Laurence Latu-Romain, and Patthranit Wongpromrat. "CHAPTER 4 High Temperature Oxidation of Stainless Steels." Solid State Phenomena 300 (February 2020): 81–106. http://dx.doi.org/10.4028/www.scientific.net/ssp.300.81.
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This chapter is dedicated to the description of high temperature oxidation of both chromia and alumina forming alloys. The defect structures of iron and chromium are firstly reviewed. The effects of elements on stainless steel oxidation behaviour are further addressed. For the chromia-forming stainless steel, the oxidation rate is reduced with the increased silicon content but not in a monotonic manner. Titanium and niobium can reduce breakaway oxidation of Fe–18Cr–10Ni austenitic stainless steel. Titanium can enhance the adhesion of scale to the Fe–18Cr by mechanical keying effect of TiO2 formed at the steel/scale interface. For the alumina-forming stainless steel, the formation of alumina and its transformation during oxidation are reviewed. Chromium can be added to reduce the critical aluminium content in the steels in order to form alumina at high temperatures. The addition of reactive elements with appropriate level can improve scale adhesion and reduce the steel oxidation rate. Refractory element like molybdenum can increase strength of material but also accelerate the oxidation rate of the steels containing reactive elements. The development of new alumina-forming austenitic alloy grades is finally described.
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Klenam, D. E. P., L. H. Chown, M. J. Papo, and L. A. Cornish. "Phase proportions, carbon equivalent, mechanical properties and their effect on material cost of railway axle steels." MRS Advances 3, no. 37 (2018): 2169–81. http://dx.doi.org/10.1557/adv.2018.348.
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AbstractCommuter trains with solid axle configuration are produced from medium carbon steel due to cost restrictions. High-speed trains have hollow axle configuration for reduced weight and are made from high strength low-alloy (HSLA) steels. The HSLA steels have higher amounts of C, Cr, Ni, Mo, V and Nb, and are more expensive than medium carbon steels. The effects of phase proportions, carbon equivalent (CE), yield strength and ultimate tensile strength (UTS) on material costs of existing railway axle steels were studied using Thermo-Calc. Medium carbon rail axle steels had higher Fe3C phase proportions than the HSLA steel rail axle grades. Higher affinity of Cr, Mo and V for C than Fe resulted in decreased cementite proportions. The HSLA steels had yield strengths above 370 MPa, and UTS above 750 MPa, with increased material cost above $3300 per ton. A scattered distribution was observed for the pearlite weight fraction and material costs, with most between $3200 and $3400. The yield and tensile strengths increased with increasing carbon equivalent and pearlite weight fraction. The data aided the selection and design of alloys with better mechanical and corrosion properties at reduced material cost.
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Kučerová, Ludmila, Hana Jirkova, and Andrea Jandová. "THERMO-MECHANICAL TREATMENT OF 42SICR AND 42MNSI STEELS." Acta Metallurgica Slovaca 23, no. 3 (September 27, 2017): 244. http://dx.doi.org/10.12776/ams.v23i3.968.
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<p class="AMSmaintext">Two high strength low alloyed steels with 0.4%C, 0.6%Mn, 2%Si and either 1.3% of chromium or without chromium were used in this work to evaluate the effect of chromium on the final microstructure obtained by thermo-mechanical processing. Various heating temperatures, cooling rates and bainitic hold temperatures were tested. High strengths around 1700 MPa were achieved for the chromium alloyed steel, however total elongation reached only 9%. Chromium-free steel turned out to be better suited for TRIP (transformation induced plasticity) processing. The relatively high strengths around 900 MPa were in this case accompanied by very high total elongations exceeding 30%. The final microstructure of chromium-free steel was also more typical for TRIP steel, as it consisted mainly of the mixture of bainite and polygonal ferrite. </p>
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Gavrilyuk, V. G., and H. Berns. "High-strength austenitic stainless steel." Metal Science and Heat Treatment 49, no. 11-12 (November 2007): 566–68. http://dx.doi.org/10.1007/s11041-007-0104-8.
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Petrakov, A. F., O. K. Revyakina, and L. P. Kapranova. "A high-strength maraging steel." Metal Science and Heat Treatment 35, no. 11 (November 1993): 633–38. http://dx.doi.org/10.1007/bf00712285.
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Ahlborn, Theresa M., and Timothy C. DenHartigh. "Comparative Bond Study of Stainless and High-Chromium Reinforcing Bars in Concrete." Transportation Research Record: Journal of the Transportation Research Board 1845, no. 1 (January 2003): 88–95. http://dx.doi.org/10.3141/1845-10.
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Concrete bridge decks in corrosive environments have used several methods to prevent corrosion of the reinforcing steel including the use of alternative steels as reinforcement. While research has been conducted on corrosion resistance, very little information is available about the bond strength of alternative metallic reinforcement such as solid stainless steels and high-strength, high-chromium (HSHC) alloys. Therefore, the tensile bond strengths of three alternative metallic steel reinforcements in concrete are compared with conventional A615 Grade 60 steel reinforcement. Two types of stainless steel were considered, 316LN and 2205 duplex. An HSHC microcomposite bar was also considered. A total of 250 bond tests were performed with beam-end specimens similar to the ASTM A944 specimen. Bonded lengths of 4 to 12 in. were used for No. 4 and No. 6 reinforcing bars. Concrete clear cover for all tests was 1½ in. to produce cracking bond failure. No transverse reinforcement was present. The normal strength concrete was typical of that used in Michigan bridge decks. Statistical comparisons of bond test results with predicted values for bond strength of A615 reinforcement revealed there was no reason to believe the bond strength of the alternative metallic reinforcing bars was less than predicted. The conservatism of the current development-length relationships generally predicted lower bond strengths than were observed. Therefore, no modifications are suggested when estimating the development length of these reinforcements as a one-to-one replacement for A615 Grade 60 reinforcement, No. 4 to No. 6 bars, using standard development-length relationships.
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Il'ina, V. P., and R. I. �ntin. "Structural strength of high-strength steel Kh5MSFA." Metal Science and Heat Treatment 33, no. 6 (June 1991): 459–62. http://dx.doi.org/10.1007/bf00775381.
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West, John C. "The Benefits of a Modified-Chemistry, High-Strength, Low-Alloy Steel." Journal of Ship Production 3, no. 02 (May 1, 1987): 111–18. http://dx.doi.org/10.5957/jsp.1987.3.2.111.
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Steels with 50 ksi and up yield points usually acquire their strength from some form of heat treatment. Most of these steels, 11/2 in. thick and up, must be welded using sustained preheat and controlled interpass temperatures, plus controlled welding heat input of approximately 50 to 60 kJ/in. These two items can add as much as 50 percent to the cost of submerged-arc welding, and increases of up to 30 percent are common for manual welding when compared with lower-strength steels previously used. To reduce costs, a quenched and precipitation-hardened steel, ASTM A710 Grade A Class 3, with a high degree of weldability, was tested. This steel, which can be welded without sustained preheat and almost unlimited heat input, has been extensively tested in thicknesses from 21/4 through 6 in. Although this steel costs more than the usual quenched-and-tempered plates at these strength levels, reductions of 40 to 75 percent in welding labor costs are probable. In addition, sizeable material savings should be realized when these items are used in place of HY-80 and HY-100.
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Wisutmethangoon, S., T. F. Kelly, P. P. Camus, J. E. Flinn, D. J. Larson, and M. K. Miller. "Analysis of Nanometer-Scale Precipitation in a Rapidly Solidified Stainless Steel." Microscopy and Microanalysis 3, S2 (August 1997): 981–82. http://dx.doi.org/10.1017/s143192760001179x.
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Though stainless steels are important technologically for a wide range of applications, they are not generally known for their very high strength. We have rapid-solidification-processed many stainless steels by gas atomization and achieved strength improvements of over 50% relative to conventionally-processed stainless steels with concomitant improvement in corrosion and oxidation behavior. These strength improvements are most pronounced after aging treatments when elevated concentrations of oxygen and vanadium are present in the stainless steel. An austenitic (FCC) stainless steel (Fe-16%Ni-9%Cr-0.5%Mn-0.2%V-0.0137%N-0.008%O by weight) was prepared by gas atomization and consolidated by hot extrusion at 900°C. These specimens were heat treated for 1 hour at 1000°C and aged at 600°C for 500 hours.The microstructure of each alloy composition was observed in TEM with bright field imaging. After aging, most alloys showed the same precipitate morphology as before aging. An obvious change, however, was found only in the alloy with highest oxygen content.
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Kaščák, Ľuboš, and Emil Spišák. "Effect of Welding Parameters on the Quality of Spot Welds Combining AHSS Steel and HSLA Steel." Key Engineering Materials 586 (September 2013): 162–65. http://dx.doi.org/10.4028/www.scientific.net/kem.586.162.
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The resistance spot welding of dissimilar materials is generally more challenging than that of similar materials due to differences in the physical, chemical and mechanical properties of the base metals. Advanced high strength steels and high strength low alloy steels are utilized in automotive industry to reduce weight of the vehicle body and consequently lowering the fuel consumption to achieve the lowest possible fuel consumption, high active and passive safety of passengers while decreasing the amount of emission. The influence of the primary welding parameters, especially welding current, microhardness and tensile shear load bearing capacity of dissimilar welds between TRIP 40/70 as an Advanced High Strength Steel and H220PD as a High-Strength Low-Alloy steel has been investigated in this paper.
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Scherbakov, A. P. "Material and method selection for increasing the wear resistance of construction machines components." Russian Automobile and Highway Industry Journal 17, no. 4 (August 28, 2020): 464–75. http://dx.doi.org/10.26518/2071-7296-2020-17-4-464-475.
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Introduction. The article examines the problem of choosing a material and method for increasing the wear resistance of construction machines elements. The performance of construction machines is affected by the reliability of the parts used. The selection of materials for their manufacture allows to calculate the probability of how such elements will affect its ability to work and productivity.Materials and methods. In the process of determining the material and the method for increasing the wear resistance of construction machines, structural steels with various chemical compositions were selected: lowcarbon 08ps (as a model material), 10, 20.30, St3 and low-alloy steels 09G2S and 10HSND, as well as high-carbon steel 65G and boron steel 30MnB5. The methods as high temperature annealing, normalization, injection and high temperature release, thermocyclic processing, cold plastic deformation, thermocyclic processing of steels after cold plastic deformation were used.Results. During the experiment, it was found that both for low-carbon 08ps, 10, 20, 30, St3, and for low-alloy structural steels 09G2S and 10HSND, as well as for high-carbon steel 65G and for boron-containing steel 30MnB5, an increase in the number of TCT cycles (thermal cycling) leads to an increase in the strength properties of the metal. With an increase in the number of cycles over 3-6, the increase in strength properties slows down significantly. Conclusion. In contrast to heat treatment, TCO allows to identify the positive effect of alloying on strength and plastic properties to a greater extent. At the same time, significantly increasing the strength and plasticity, it is possible to obtain previously unattainable values of the work of destruction of alloy steels in the process of various types of loading. Accordingly, the preliminary preparation of steel for the production of individual elements of machines and mechanisms will increase their strength and wear resistance.
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Dong, Zhong Bo, Han Xiong Dong, and Xia Hong. "Simulation Research on Process Adaptability of Alloy Structural Steel 50Mn2V." Advanced Materials Research 573-574 (October 2012): 1178–81. http://dx.doi.org/10.4028/www.scientific.net/amr.573-574.1178.
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This paper analyzes the adaptability of process of alloy structural steel 50Mn2V by simulating research. Through the high temperature tensile test、the multi-pass deformation test we study the deforming resistance characteristics of 50Mn2V steel, and carry on the contrast with high strength steels P20（3Cr2Mo）of a factory; Through thermo-plasticity test the high temperature thermoplastic of 50Mn2V steel is studied. The test result indicates a factory has ability to produce the high strength 50Mn2V steel completely with present equipment.
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Stradomski, Z., S. Stachura, and G. Stradomski. "Fracture Mechanisms in Steel Castings." Archives of Foundry Engineering 13, no. 3 (September 1, 2013): 88–91. http://dx.doi.org/10.2478/afe-2013-0066.
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Abstract The investigations were inspired with the problem of cracking of steel castings during the production process. A single mechanism of decohesion - the intergranular one - occurs in the case of hot cracking, while a variety of structural factors is decisive for hot cracking initiation, depending on chemical composition of the cast steel. The low-carbon and low-alloyed steel castings crack due to the presence of the type II sulphides, the cause of cracking of the high-carbon tool cast steels is the net of secondary cementite and/or ledeburite precipitated along the boundaries of solidified grains. Also the brittle phosphor and carbide eutectics precipitated in the final stage solidification are responsible for cracking of castings made of Hadfield steel. The examination of mechanical properties at 1050°C revealed low or very low strength of high-carbon cast steels.
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Timokhina, Ilana B., Peter D. Hodgson, Simon P. Ringer, Rong Kun Zheng, and Elena V. Pereloma. "Characterization of Nano-Scale Particles in Hot-Rolled, High Strength Low Alloy Steels (HSLA)." Materials Science Forum 561-565 (October 2007): 2083–86. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.2083.
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The contribution of nano-scale particles observed using Atom Probe Tomography in an increase of yield strength of conventional and advanced HSLA steels was studied. The advanced HSLA steel showed higher yield strength than conventional HSLA steel. There were two types of carbides, which primarily contribute to an increase in yield strength of conventional HSLA steel: (i) coarse TiC with average size of 25±5nm and (ii) fine TiC with average radius of 3±1.2nm. The presence of two types of carbides was found in the microstructure of advanced HSLA steel: (i) nano-scale Ti0.98Mo0.02C0.6 carbides with average radius of 2.2±0.5nm, and (ii) C19Cr7Mo24 particles with an average radius of 1.5±0.3nm. The contribution of precipitation hardening in the yield strength of advanced HSLA steel due to the nano-scale particles was 174MPa, while this value in the conventional HSLA steel was 128MPa.
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Shirazi, H., Mahmoud Nili-Ahmadabadi, A. Fatehi, and S. Hossein Nedjad. "Effect of Severe Plastic Deformation on Mechanical Properties of Fe-Ni-Mn High Strength Steel." Advanced Materials Research 83-86 (December 2009): 16–23. http://dx.doi.org/10.4028/www.scientific.net/amr.83-86.16.
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Fe-Ni-Mn martensitic steels show excellent age hardenability but suffer from embrittlement after aging. Discontinuous coarsening of grain boundary precipitates was found as the main source of embrittlement. Effect of cold rolling and equal channel angular pressing on the mechanical properties of an Fe-10Ni-7Mn steel was investigated. Cold rolling for 20%, 40%, 60%, 80% and 90% and equal channel angular pressing for four passes through the Bc route were carried out on a solution annealed material with subsequent aging at 753 K. Hardness measurement, tensile test and scanning electron microscopy were used to study mechanical properties and microstructural features of the as-deformed and aged alloys. Improvement in tensile properties of the as-deformed and aged alloys was found. A tensile strength of about 1840 MPa along with 3% elongation were determined for cold rolled by 90% thickness reduction and aged alloy, while conventional steel shows a premature fracture stress of 820 MPa with zero ductility. It was also indicated that after heavy cold rolling ductility increases in comparison to the equal channel angular pressed and aged alloy.
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Liu, Yu, Dongwei Fan, Raymundo Arróyave, and Ankit Srivastava. "Microstructure-Based Modeling of the Effect of Inclusion on the Bendability of Advanced High Strength Dual-Phase Steels." Metals 11, no. 3 (March 5, 2021): 431. http://dx.doi.org/10.3390/met11030431.
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Advanced high strength dual-phase steels are one of the most widely sought-after structural materials for automotive applications. These high strength steels, however, are prone to fracture under bending-dominated manufacturing processes. Experimental observations suggest that the bendability of these steels is sensitive to the presence of subsurface non-metallic inclusions and the inclusions exhibit a rather discrete size effect on the bendability of these steels. Following this, we have carried out a series of microstructure-based finite element calculations of ductile fracture in an advanced high strength dual-phase steel under bending. In the calculations, both the dual-phase microstructure and inclusion are discretely modeled. To gain additional insight, we have also analyzed the effect of an inclusion on the bendability of a single-phase material. In line with the experimental observations, strong inclusion size effect on the bendability of the dual-phase steel naturally emerge in the calculations. Furthermore, supervised machine learning is used to quantify the effects of the multivariable input space associated with the dual-phase microstructure and inclusion on the bendability of the steel. The results of the supervised machine learning are then used to identify the contributions of individual features and isolate critical features that control the bendability of dual-phase steels.
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Węgrzyn, Tomasz, Tadeusz Szymczak, Bożena Szczucka-Lasota, and Bogusław Łazarz. "MAG Welding Process with Micro-Jet Cooling as the Effective Method for Manufacturing Joints for S700MC Steel." Metals 11, no. 2 (February 5, 2021): 276. http://dx.doi.org/10.3390/met11020276.
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Advanced high-strength steel (AHSS) steels are relatively not very well weldable because of the dominant martensitic structure with coarse ferrite and bainite. The utmost difficulty in welding these steels is their tendency to crack both in the heat affected zone (HAZ) and in weld. The significant disadvantage is that the strength of the welded joint is much lower in comparison to base material. Adopting the new technology regarding micro-jet cooling (MJC) after welding with micro-jet cooling could be the way to steer the microstructure of weld metal deposit. Welding with micro-jet cooling might be treated as a very promising welding S700MC steel process. Tensile and fatigue tests were mainly carried out as the main destructive experiments for examining the weld. Also bending probes, metallographic structure analysis, and some non-destructive measurements were performed. The welds were created using innovative technology by MAG welding with micro-jet cooling. The paper aims to verify the fatigue and tensile properties of the thin-walled S700MC steel structure after welding with various parameters of micro-cooling. For the first time, micro-jet cooling was used to weld S700MC steel in order to check the proper mechanical properties of the joint. The main results are processed in the form of the Wöhler’s S–N curves (alternating stress versus number cycles to failure).
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Ueda, Keiji, Daichi Izumi, Toshinori Ishida, and Yoshiaki Murakami. "Effect of Alloying Element on Mechanical Properties of High Strength Austenitic Steel." Materials Science Forum 1016 (January 2021): 678–84. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.678.
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A high strength austenitic steel is expected as a structural material for cryogenic use because fcc material does not cause a cleavage fracture despite high strength. High manganese steel which is a strong candidate material of the cryogenic high strength austenitic steel was originally famous for the Hadfield steel and widely applicable in actual use. In general, an excellent cryogenic toughness of the high manganese steels is achieved by obtaining stable fcc microstructure with an adequate amount manganese which is a typical austenite former alloy. However, as addition of manganese is not effective for increasing strength, other strengthening alloying elements like carbon and chromium need to be added. In this study, an effect of alloying elements on strength and cryogenic toughness of the high manganese austenitic steel is studied.
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Souto Maior Tavares, Sérgio, Adriana da Cunha Rocha, Manoel Ribeiro da Silva, Carlos Augusto Silva de Oliveira, and Rachel Pereira Carneiro da Cunha. "Microstructural Characterization of New Super-Ferritic-Martensitic Stainless Steel." Solid State Phenomena 257 (October 2016): 52–55. http://dx.doi.org/10.4028/www.scientific.net/ssp.257.52.
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The demand for high strength materials with improved corrosion resistance boosted the development of supermartensitic steels from conventional martensitic stainless steels The first alloys were designed with 11-13%Cr, extra-low carbon and nickel addition. More recently, experimental alloys with higher Cr (15-17%) and other ferritizing elements (Mo, W, Nb,…) were developed with the aim of obtain higher corrosion resistance in high chloride environments. In this work, the microstructure features of a new 17%Cr stainless steel were investigated.
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Jirková, Hana, Kateřina Opatová, Štěpán Jeníček, Jiří Vrtáček, Ludmila Kučerová, and Petr Kurka. "USE OF MULTI-PHASE TRIP STEEL FOR PRESS-HARDENING TECHNOLOGY." Acta Metallurgica Slovaca 25, no. 2 (June 28, 2019): 101. http://dx.doi.org/10.12776/ams.v25i2.1267.
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<p class="AMSmaintext">Development of high strength or even ultra-high strength steels is mainly driven by the automotive industry which strives to reduce the weight of individual parts, fuel consumption, and CO<sub>2</sub> emissions. Another important factor is to improve passenger safety. In order to achieve the required mechanical properties, it is necessary to use suitable heat treatment in addition to an appropriate alloying strategy. The main problem of these types of treatments is the isothermal holding step. For TRIP steels, the holding temperature lies in the field of bainitic transformation. These isothermal holds are economically demanding to perform in industrial conditions. Therefore new treatments without isothermal holds, which are possible to integrate directly into the production process, are searched. One way to produce high-strength sheet is the press-hardening technology. Physical simulation based on data from a real-world press-hardening process was tested on CMnSi TRIP steel. Mixed martensitic-bainitic structures with ferrite and retained austenite (RA) were obtained, having tensile strengths in excess of 1000 MPa.</p>
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Kostina, M. V., P. Yu Polomoshnov, V. M. Blinov, S. O. Muradyan, and V. S. Kostina. "Cold resistance of new casting Cr – Mn – Ni – Mo – N steel with 0.5 % of N. Part. 1." Izvestiya. Ferrous Metallurgy 62, no. 11 (December 23, 2019): 894–906. http://dx.doi.org/10.17073/0368-0797-2019-11-894-906.
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The authors have studied cold resistance of thelaboratorymetal of a new austenitic grade of nitrogen-containing casting steel (21 – 22) Cr – 15Mn – 8Ni – 1.5Mo – V (Russian grade 5Kh21АG15N8МFL) with nitrogen content of 0.5 % and yield strength of ~400 MPa. The temperature dependence of impact toughness was constructed in the range +20 ... –160 °C and it was shown that the steel is characterized by a wide temperature range of the viscous-brittle transition with T DBT = –75 °C, at which KCV = 120 ± 10 J/cm2. Comparison material – industrial, centrifugally cast 18Cr – 10Ni steel (grade 12Kh18N10-CC) has such a KCV level at +20 °C. It is not prone to viscous-brittle transition, its impact strength decreases more gently and at temperatures lower than –80 °C and its KCV level is higher than that of nitrous steel. However, in the entire range of climatic temperatures, nitrous casting steel with 0.5 % of N exceeds its impact strength. The studied steels have residual δ-ferrite in the cast structure in an amount of up to ~10 % in Cr– Ni industrial steel and a smaller amount in laboratory nitrous steel. It is enriched by chromium, up to 26 and 34 wt. % respectively, and contains ~14 % of Mn in nitrogen steel. Presence of Mn does not affect the nature of fractures at climatic temperatures. However, δ-ferrite of nitrous steel at –160 °C is beyond the cold brittle threshold. Therefore, its fracture obtained at this temperature contains numerous cracks in δ-ferrite crystals. The critical fragility temperature below which this material is not recommended for use is Тк ≈ –110 °С; it was determined by the criterion method. It corresponds to a level of KCV of 68 – 83 J/cm2, higher than the level of KCU at +20 °C, allowed by the standard of the Russian Federation for castings from austenitic class of steels (up to 59 J/cm2 ). Based on a comparison of literature and our own data, it was concluded that it is impossible to ensure high cold resistance and, at the same time, high strength, due to alloying of economically alloyed nickel (up to 4 %) corrosion-resistant steels by 0.5 – 0.6 % of N.
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Cao, Yuxin, Xiangliang Wan, Feng Zhou, Yu Shen, Yu Liu, Guangqiang Li, and Kaiming Wu. "Impact of Mo content on the microstructure– toughness relationship in the coarse-grained heat-affected zone of high-strength low-alloy steels." International Journal of Materials Research 112, no. 2 (February 1, 2021): 98–107. http://dx.doi.org/10.1515/ijmr-2020-7842.
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Abstract The present study elucidates the influence of Mo content on the microstructure – toughness relationship in the coarsegrained heat-affected zone of high-strength low-alloy steels. The low-Mo and high-Mo steels were subjected to 100 kJ cm–1 heat input welding thermal cycling. The results indicated that (Ti,Mo)-carbonitrides were formed in high-Mo steel, whereas (Ti,Nb)-carbonitrides were formed in low-Mo steel. The finer and dispersed precipitates in high-Mo steel refined the prior austenite grain in the coarse-grained heat-affected zone based on the grain boundary pinning effect. However, the smaller prior austenite grain and excessive Mo content induced the formation of an entirely bainitic microstructure in high-Mo steel. Furthermore, a higher fraction of martensite –austenite constituents was observed in high-Mo steel. These results could be responsible for the deterioration of the toughness in the coarse-grained heat-affected zone of high-Mo steel.
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Neto, J. C. de Macêdo, J. C. M. da Costa, E. R. S. Teixeira, R. M. Teixeira Júnior, J. B. de Oliveira, T. G. Barros, T. M. Maquiné, A. C. Kieling, and G. G. d. Pino. "Mechanical Resistance of High-Speed Steels Cr-W-Mo-V, Si-Mn-Cr-Mo-V-Co, Si-Mn-Cr-Mo-V and Si-Mn-Cr-Mo-V-Co Heat Treated." Materials Science Forum 1012 (October 2020): 319–24. http://dx.doi.org/10.4028/www.scientific.net/msf.1012.319.
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In the Metal Market, it has been important to understand the structure of steels, so that it is possible to develop new cutting materials at lower costs and more resistant to high temperatures and wear. This is possible by raising the mechanical strength for solid solution in fast steels, ie, addition of alloying elements to the steel in its solid state, the alloys fundamental to this process were: cobalt, manganese, silicon, tungsten and vanadium. Among the thermal treatments, tempering and quenching were used to raise the degree of hardness and strength of the steel. The samples studied were high speed steels HS6-5-3, HS6-5-3-5, K190 e K390. Hardness and metallographic tests were carried out on the samples and with the results generated, it was possible to draw a comparison and understand which alloying elements provide the least oxidation, corrosion and greater impact strength of fast steel.
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Vinogradov, V. N., G. M. Sorokin, and S. N. Bobrov. "Special high-strength engineering steel D5." Metal Science and Heat Treatment 31, no. 2 (February 1989): 145–55. http://dx.doi.org/10.1007/bf00738152.
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Du, Congcong, Guoying Liu, Baoru Sun, Shengwei Xin, and Tongde Shen. "A 2.9 GPa Strength Nano-Grained and Nano-Precipitated 304L-Type Austenitic Stainless Steel." Materials 13, no. 23 (November 27, 2020): 5382. http://dx.doi.org/10.3390/ma13235382.
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Austenitic stainless steel has high potential as nuclear and engineering materials, but it is often coarse grained and has relatively low yield strength, typically 200–400 MPa. We prepared a bulk nanocrystalline lanthanum-doped 304L austenitic stainless steel alloy by a novel technique that combines mechanical alloying and high-pressure sintering. The achieved alloy has an average grain size of 30 ± 12 nm and contains a high density (~1024 m−3) of lanthanum-enriched nanoprecipitates with an average particle size of approx. 4 nm, leading to strong grain boundary strengthening and dispersion strengthening effects, respectively. The yield strength of nano-grained and nano-precipitated stainless steel reaches 2.9 GPa, which well exceeds that of ultrafine-grained (100–1000 nm) and nano-grained (<100 nm) stainless steels prepared by other techniques developed in recent decades. The strategy to combine nano-grain strengthening and nanoprecipitation strengthening should be generally applicable to developing other ultra-strong metallic alloys.
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Xu, Baoyu, Peng Chen, Zhengxian Li, Di Wu, Guodong Wang, Jinyu Guo, Rendong Liu, R. D. K. Misra, and Hongliang Yi. "The Significance of Optimizing Mn-Content in Tuning the Microstructure and Mechanical Properties of δ-TRIP Steels." Metals 11, no. 3 (March 23, 2021): 523. http://dx.doi.org/10.3390/met11030523.
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The δ-TRIP steel has attracted a lot of attention for its potential application in automotive components, owing to the low density, good combination of strength, and ductility. As the difficulty in yield strength further increasement is caused by large fraction ferrite, the work hardening ability was enhanced by optimizing the manganese (Mn)-content in this study. Three δ-TRIP steels with different manganese (Mn)-content were designed to explore the significant effect of Mn content on the work hardening behavior in order to develop high strength steel suitable for the industrial continuous annealing process. The detailed effect of Mn on microstructure evolution and deformation behavior was studied by scanning electron microscope (SEM), interrupted tensile tests, X-ray diffraction (XRD), and in-situ electron backscattered diffraction (EBSD). The study suggested that 2 Mn steel has the lowest degree of bainitic transformation, as a result of fine grain size of prior austenite. The large TRIP effect and dislocation strengthening improve the work hardening rate, resulting in 2 Mn steel exhibiting comparable mechanical properties with the QP980 steels. The retained austenite in 1.5 Mn steel progressively transformed into martensite and sustained the strain to a high strain value of 0.40, showing a good strength-ductility balance.
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Bodnar, R. L., J. R. Michael, S. S. Hansen, and R. I. Jaffee. "Progress in the Design of an Improved High-Temperature 1 Percent CrMoV Rotor Steel." Journal of Engineering Materials and Technology 112, no. 1 (January 1, 1990): 99–115. http://dx.doi.org/10.1115/1.2903194.
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Silicon-deoxidized, tempered bainitic 1 percent CrMoV steel is currently used extensively for high-temperature steam turbine rotor forgings operating at temperatures up to 565°C due to its excellent creep rupture properties and relative economy. There is impetus to improve the creep rupture strength of this steel while maintaining its current toughness level and vice versa. The excellent creep rupture ductility of the low Si version of this steel allows the use of a higher austenitizing temperature or tensile strength level for improving creep rupture strength without loss in creep ductility or toughness. When the tensile strength of this steel is increased from 785 to 854 MPa, the creep rupture strength exceeds that of the more expensive martensitic 12CrMoVCbN steel currently used for high-temperature rotor applications where additional creep rupture strength is required. The toughness of 1 percent CrMoV steel is improved by lowering the bainite start (Bs) temperature in a “superclean” base composition which is essentially free of Mn, Si, P, S, Sb, As and Sn. The Bs temperature can be lowered through the addition of alloying elements (i.e., C, Ni, Cr, and Mo) and/or increasing the cooling rate from the austenitizing temperature. Using these techniques, the 50 percent FATT can be lowered from approximately 100°C to below room temperature, which provides the opportunity to eliminate the special precautionary procedures currently used in the startup and shutdown of steam turbines. The most promising steels in terms of creep rupture and toughness properties contain 2.5 percent Ni and 0.04 percent Cb (for austenite grain refinement and enhanced tempering resistance). In general, the creep rupture strength of the superclean steels equals or exceeds that of the standard 1 percent CrMoV steel. In addition, the superclean steels have not been found to be susceptible to temper embrittlement, nor do they alter the room temperature fatigue crack propagation characteristics of the standard 1 percent CrMoV steel. These new steels may also find application in combination high-temperature-low-temperature rotors and gas turbine rotors.
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Wiewiórowska, S. "Analysis of the Influence of Drawing Process Parameters on the Mechanical Properties of Trip-Structure Steel Wires." Archives of Metallurgy and Materials 58, no. 2 (June 1, 2013): 573–78. http://dx.doi.org/10.2478/amm-2013-0040.
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The research concerned with wire drawing processes of medium-carbon steel with TRIP effect classified into group of AHSS (Advanced High Strength Steel) steels, which are the multiphase steels offering a unique combination of high strength and ductility, has been shown in the work. Such combination is achieved through the transformation of retained austenite to martensite in deformation process called TRIP effect (Transformation Induced Plasticity). Studies reported in the literature relate mainly to the research on the car body sheet rolling and heat treatment processes, which does not allow the results of this research to be referred to the analysis of drawing processes. Therefore, the need has arisen for developing and conducting comprehensive studies on the process of drawing TRIP steels wires and identification the new application areas for these materials.
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Bulatović, Srđan, Vujadin Aleksić, Ljubica Milović, and Bojana Zečević. "AN ANALYSIS OF IMPACT TESTING OF HIGH STRENGTH LOW-ALLOY STEELS USED IN SHIP CONSTRUCTION." Brodogradnja 72, no. 3 (July 1, 2021): 1–12. http://dx.doi.org/10.21278/brod72301.
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Brittle damages have been examined widely since welding became common practice when it comes to carrying out robust structures. Welded structure of the ship hull has to be continuous. Brittle damages that occur on hull structures have always been examined thoroughly. Cracks are most commonly initiated at locations where stress concentrators exist. These concentrators can originate due to flaws that occur during the design phase or due to mistakes that occur during the assembly of the structure. When it comes to failures and damages that occur at ship structures, it has been noticed that damages due to brittleness practically always happen at low temperatures. Impact test analysis is significant due to the fact that it replicates the ductile to brittle transition of steel in practically identical range of temperatures for all ship structures. Impact of ductile-brittle transition temperature is an important factor especially because there have been many ship failures and damages in history. In ship structures made of welded joints of high strength low-alloy (HSLA) steels with their segments (parent metal, weld metal and heat-affected-zone), the toughness test determines the tendency of steel to brittle fracture, respectively the tendency to increase brittleness during exploitation. Parameters obtained by testing the properties of plasticity are the fundamental for the composition of ship structures with the aim of realize strengths under tested load. The test results of high strength low-alloy steel toughness assessment at different test temperatures show that temperature significantly affects the impact toughness of steels and their alloys.
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Aromaa, Jari, Antero Pehkonen, Sönke Schmachtel, Istvan Galfi, and Olof Forsén. "Electrochemical Determination of Hydrogen Entry to HSLA Steel during Pickling." Advances in Materials Science and Engineering 2018 (2018): 1–7. http://dx.doi.org/10.1155/2018/3676598.
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Pickling with hydrochloric acid is a standard method to clean steel surfaces before hot-dip galvanizing. When normal low strength steels are pickled, hydrogen formed in pickling reactions does not have any significant harmful effect on the mechanical properties of steel. However, in pickling of steels with higher strength, the penetration of hydrogen into the steel may cause severe damages. The effect of pickling of high-strength low-alloy (HSLA) steels was investigated using a cell construction based on the Devanathan-Stachurski method with modified anodic surface treatment and hydrogen production using acid. The penetration and the permeability of hydrogen were measured using an electrochemical cell with hydrochloric acid on the one side of the steel sample and a solution of NaOH on the other side. No protective coating, for example, palladium on the anodic side of the sample, is needed. The penetration rate of hydrogen into the steel and exit rate from the steel were lower for higher strength steel.
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Sydorchuk, O. M. "Steel with control austenitic transformation during operation." Metaloznavstvo ta obrobka metalìv 98, no. 2 (June 7, 2021): 47–53. http://dx.doi.org/10.15407/mom2021.02.047.
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The intermediate class of steels, which at room temperature belong to the ferritic state, and at operating temperature pass into the austenitic region, are called steels with control of austenitic transformation during operation. The possibility of increasing the service life of such intermediate steels at high temperatures (above the critical point A3) is shown. For the first time, the cast structure and phase-structural state of steel (grade 4Kh3N5М3F) obtained by electroslag remelting were studied. An improved composition of steel (4Kh4N5М3F) for the production of stamping tools for hot pressing of copper, copper and aluminum alloys is proposed. When setting the critical points (A1 and A3) of the investigated steel, which was confirmed by the results of high-temperature X-ray phase analysis, it was possible to optimize the heat treatment (annealing) of steel 4Kh3N5M3F and 4Kh4N5M4F2 in cast and forged condition, which facilitated processing tool. The results of researches on optimization of modes of heat treatment (hardening, tempering) of steel are given. The mechanical properties (strength, toughness, heat resistance) of steel in cast and forged state depending on the tempering and tempering temperature are determined. The tempering brittleness of the experimental steel is determined. An experimental-industrial test of a stamping tool (die dies, extruder parts) made of the investigated steel was carried out. The possibility of using stamped steel with adjustable austenitic transformation for a wide range of operating temperatures of hot deformation of aluminum alloy AK7h (450-500 ºC), copper M1 (600-630 ºC) and copper-nickel alloy MNZh 5-1 (900-950 ºC) with increased service life in comparison with steels of ferrite class 4Kh5МF1S and 3Kh3М3F. Keywords: die steel, composition, thermal treatment, structure, mechanical properties.
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Jiang, Han, Yanlin He, Li Lin, Rendong Liu, Yu Zhang, Weisen Zheng, and Lin Li. "Microstructures and Properties of Auto-Tempering Ultra-High Strength Automotive Steel under Different Thermal-Processing Conditions." Metals 11, no. 7 (July 14, 2021): 1121. http://dx.doi.org/10.3390/met11071121.
Full textAbstract:
Automotive steels with ultra-high strength and low alloy content under different heating and cooling processes were investigated. It was shown that those processes exhibited a great influence on the performance of the investigated steels due to the different auto-tempering effects. Compared with the steels under water quenching, there was approximately a 70% increase in the strength and elongation of steels under air cooling, in which the martensite was well-tempered. Although the elongation of the steel with a microstructure composed of ferrite, well-tempered martensite and less-tempered martensite could exceed 15%, the hole expansion ratio was still lower because of the undesirable hardness distribution between the hard phases and the soft phases. It followed from the calculation results based on SEM, TEM and XRD analyses, that for the steel under air cooling, the strengthening mechanism was dominated by the solid solution strengthening and the elongation was determined by the auto-tempering of martensite. Experiments and analyses aimed to explore the strengthening and plasticity mechanisms of auto-tempering steels under the special process of flash heating.
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Bae, Hyo Ju, Kwang Kyu Ko, Hyoung Seok Park, Jae Seok Jeong, Jung Gi Kim, Hyokyung Sung, and Jae Bok Seol. "Development of 1.2 GPa Ferrite-based Lightweight Steels via Low-temperature Tempering." Korean Journal of Metals and Materials 59, no. 10 (October 5, 2021): 683–91. http://dx.doi.org/10.3365/kjmm.2021.59.10.683.
Full textAbstract:
Previously reported low-Mn ferritic-based lightweight steels are potential candidates for industrial applications, however, they typically exhibit lower strength, with < 1 GPa and lower strength-ductility balance, than medium- and high-Mn austenitic lightweight steels. Herein, we introduce a low-temperature tempering-induced partitioning (LTP) treatment that avoids the strength-ductility dilemma of low-Mn ferriticbased steels. When the LTP process was performed at 330 oC for 665 s, the strength of typical ferritic base Fe-2.8Mn5.7Al0.3C (wt%) steel with heterogeneously sized metastable austenite grains embedded in a ferrite matrix, exceeded 1.1 GPa. Notably, the increased strength-ductility balance of the LTP-processed ferritic steel was comparable to that of the high-Mn based austenitic lightweight steel series. Using microscale to nearatomic scale characterization we found that the simultaneous improvement in strength and total elongation could be attributed to size-dependent dislocation movement, and controlled deformation-induced martensitic transformation.