Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment  

作　　者：Chang-sheng Li Bin-zhou Li Xin Jin Yu Wang 

机构地区：[1]State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang,110819,Liaoning,China [2]Ansteel Group,Ansteel Beijing Research Institute,Beijing,102211,China

出　　处：《Journal of Iron and Steel Research International》2021年第3期360-369,共10页

基　　金：The authors are grateful to the funding by National High Technology Research and Development Program of China(863 Program,Grant No.2012AA03A503).

摘　　要：Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment were investigated.Conventional treatment sample was quenched and tempered at 180℃ for 2 h.Cryogenic treatment samples were quenched,cryogenically treated at−80 and−196℃ for 4 h,slowly returned to room temperature and thereafter tempered at 180℃ for 2 h,and finally tempered at 180℃ for 2 h.The scanning electron microscope,electron backscattering diffraction,X-ray diffraction and transmission electron microscope were adopted for microstructure characterization.The results show that cryogenic treatment increases the fraction of high-angle grain boundaries and the precipitation of finely dispersed carbides in the matrix,decreases the volume fraction of inter-lath retained austenite,and hence improves the strength and hardness.Compared with the conventional treatment,the hardness,yield strength and ultimate tensile strength of the steel after cryogenic treatment are increased by 11.7%,12.6%and 18.3%,respectively,while the impact energy is decreased by 9.8%.

关 键 词：Bearing steel Cryogenic treatment Lath martensite Retained austenite Mechanical property 

分 类 号：TG142.1[一般工业技术—材料科学与工程]