scholarly journals Overcoming Strength-Ductility Trade-Off at Cryogenic Temperature of Low Carbon Low Alloy Steel via Controlling Retained Austenite Stability

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 157
Author(s):  
Xuelin Wang ◽  
Zhenjia Xie ◽  
Chengjia Shang ◽  
Gang Han
Keyword(s):  
Retained Austenite ◽  
Mechanical Stability ◽  
Testing Temperature ◽  
Low Carbon ◽  
Transformation Induced Plasticity ◽  
Strain Behavior ◽  
Austenite Stability ◽  
Work Hardening Rate ◽  
Multiphase Steel ◽  
Strength And Ductility

Stress–strain behavior of a low carbon low alloy multiphase steel with ferrite, tempered bainite, and retained austenite was studied at different cryogenic temperatures. Results indicated that both strength and ductility were enhanced with decreasing tensile testing temperature. The enhancement of both strength and ductility was attributed to the decreased mechanical stability of retained austenite with decreasing temperature, resulting in sufficient transformation induced plasticity (TRIP) effect for increasing work hardening rate.

Effects of Retained Austenite Stability on Mechanical Properties of High Strength TRIP Steel

2012 ◽  
Vol 602-604 ◽  
pp. 287-293
Author(s):  
Zhi Feng Li ◽  
Ren Yu Fu ◽  
Qing Shan Li
Keyword(s):  
Mechanical Properties ◽  
Trip Steel ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
High Strength ◽  
Tensile Tests ◽  
Transformation Kinetics ◽  
Austenite Stability ◽  
Kinetics Of ◽  
Strength And Ductility

Mechanical stability of retained austenite and its effect on mechanical properties of high strength TRIP steel were studied by means of OM, SEM, TEM, XRD, and mechanical testing after various heat treatments. Results revealed that the film-type retained austenite located between bainite laths with high carbon content showed gradual martensitic transformation with strain, demonstrating a good TRIP effect. Samples annealed at 800°C and held at 420°C showed an optimum value of strength and ductility product up to 18381.2MPa%. Transformation kinetics of the retained austenite were evaluated through tensile tests and fitted by the function y=0.86-0.86×exp(-Ax). The fitting results were good.

Toward the Development of AHSS for Wear Resistant Applications

2018 ◽  
Vol 941 ◽  
pp. 568-573 ◽  
Author(s):  
Preston Wolfram ◽  
Christina Hensley ◽  
Ronald Youngblood ◽  
Rachael Stewart ◽  
Emmanuel de Moor ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Retained Austenite ◽  
Process Development ◽  
High Strength ◽  
Advanced High Strength Steel ◽  
Wear Resistant ◽  
Transformation Induced Plasticity ◽  
Enhance Wear Resistance ◽  
Improve Wear Resistance ◽  
Strength And Ductility

Advanced High Strength Steel (AHSS) developments have largely focused on automotive applications using metallurgical approaches to develop retained austenite-containing microstructures in a variety of new steels, using the transformation-induced plasticity (TRIP) effect to achieve better combinations of strength and ductility. These efforts have been extended in recent studies to explore the potential to improve wear resistance, using metastable retained austenite to enhance wear resistance for earth-moving and other applications. This paper provides selected highlights of the authors’ efforts to develop wear resistant steels using AHSS processing approaches. Some attractive product/process development opportunities are identified, and it appears that martensite-austenite microstructures produced using “quenching and partitioning” exhibit increased wear resistance.

scholarly journals Quantitative Description of External Force Induced Phase Transformation in Silicon–Manganese (Si–Mn) Transformation Induced Plasticity (TRIP) Steels

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3781
Author(s):  
Zhongping He ◽  
Huachu Liu ◽  
Zhenyu Zhu ◽  
Weisen Zheng ◽  
Yanlin He ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Carbon Steel ◽  
Trip Steel ◽  
Retained Austenite ◽  
Low Carbon Steel ◽  
High Strength ◽  
High Plasticity ◽  
Low Carbon ◽  
Transformation Induced Plasticity ◽  
Trip Steels

Transformation Induced Plasticity (TRIP) steels with silicon–manganese (Si–Mn) as the main element have attracted a lot of attention and great interest from steel companies due to their low price, high strength, and high plasticity. Retained austenite is of primary importance as the source of high strength and high plasticity in Si–Mn TRIP steels. In this work, the cold rolled sheets of Si–Mn low carbon steel were treated with TRIP and Dual Phase (DP) treatment respectively. Then, the microstructure and composition of the Si–Mn low carbon steel were observed and tested. The static tensile test of TRIP steel and DP steel was carried out by a CMT5305 electronic universal testing machine. The self-built true stress–strain curve model of TRIP steel was verified. The simulation results were in good agreement with the experimental results. In addition, the phase transformation energy of retained austenite and the work borne by austenite in the sample during static stretching were calculated. The work done by austenite was 14.5 J, which was negligible compared with the total work of 217.8 J. The phase transformation energy absorption of retained austenite in the sample was 9.12 J. The role of retained austenite in TRIP steel is the absorption of excess energy at the key place where the fracture will occur, thereby increasing the elongation, so that the ferrite and bainite in the TRIP steel can absorb energy for a longer time and withstand more energy.

Effect of retained austenite stability on cyclic deformation behavior of low‐alloy transformation‐induced plasticity steels

2019 ◽  
Vol 42 (5) ◽  
pp. 1085-1099 ◽  
Author(s):  
Peter I. Christodoulou ◽  
Alexis T. Kermanidis ◽  
Gregory N. Haidemenopoulos ◽  
Daniel Krizan ◽  
Kyriaki Polychronopoulou
Keyword(s):  
Cyclic Deformation ◽  
Deformation Behavior ◽  
Retained Austenite ◽  
Transformation Induced Plasticity ◽  
Austenite Stability ◽  
Retained Austenite Stability

scholarly journals Mechanism of the Microstructural Evolution of 18Cr2Ni4WA Steel during Vacuum Low-Pressure Carburizing Heat Treatment and Its Effect on Case Hardness

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2352
Author(s):  
Bin Wang ◽  
Yanping He ◽  
Ye Liu ◽  
Yong Tian ◽  
Jinglin You ◽  
...  
Keyword(s):  
Low Temperature ◽  
Carbon Content ◽  
Retained Austenite ◽  
Mechanical Stability ◽  
Lath Martensite ◽  
Low Pressure ◽  
Low Carbon ◽  
High Carbon ◽  
Carburized Layer ◽  
Martensite Matrix

In this study, vacuum low-pressure carburizing heat treatments were carried out on 18Cr2Ni4WA case-carburized alloy steel. The evolution and phase transformation mechanism of the microstructure of the carburized layer during low-temperature tempering and its effect on the surface hardness were studied. The results showed that the carburized layer of the 18Cr2Ni4WA steel was composed of a large quantity of martensite and retained austenite. The type of martensite matrix changed from acicular martensite to lath martensite from the surface to the core. The hardness of the carburized layer gradually decreased as the carbon content decreased. A thermodynamic model was used to show that the low-carbon retained austenite was easier to transform into martensite at lower temperatures, since the high-carbon retained austenite was more thermally stable than the low-carbon retained austenite. The mechanical stability—not the thermal stability—of the retained austenite in the carburized layer dominated after carburizing and quenching, and cryogenic treatment had a limited effect on promoting the martensite formation. During low-temperature tempering, the solid-solution carbon content of the martensite decreased, the compressive stress on the retained austenite was reduced and the mechanical stability of the retained austenite decreased. Therefore, during cooling after low-temperature tempering, the low-carbon retained austenite transformed into martensite, whereas the high-carbon retained austenite still remained in the microstructure. The changes in the martensite matrix hardness had a far greater effect than the transformation of the retained austenite to martensite on the case hardness of the carburized layer.

Microstructure and Mechanical Properties of Cold-Rolled TRIP Steel Sheets

2011 ◽  
Vol 266 ◽  
pp. 280-283 ◽  
Author(s):  
Cai Nian Jing ◽  
Xiao Hui Chen ◽  
Ming Gang Wang ◽  
Qi Zhong Tian ◽  
Zuo Cheng Wang
Keyword(s):  
Retained Austenite ◽  
High Strength ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Multiphase Microstructure ◽  
Steel Sheets ◽  
High Strength Level ◽  
Cold Rolled ◽  
Level 2 ◽  
Strength And Ductility

Transformation induced plasticity (TRIP) steels have complex multiphase microstructure composed of ferrite, bainite and retained austenite [1]. These metastable retained austenite can transforms into martensite during plastic deformation, which generates a TRIP effect resulting in excellent combination of high strength and ductility even at high strength level [2-5]. For this reason, the TRIP-aided steel sheets are suitable to fabricate automobile parts, as they can offer excellent formability without sacrifice the strength and safety requirement of the steel sheets. As a result, the development of TRIP-aided steels has been a very important issue in the automobile field.

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