Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment
Chang-sheng Li1, Bin-zhou Li2, Xin Jin1, Yu Wang1
1 State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, Liaoning, China; 2 Ansteel Group, Ansteel Beijing Research Institute, Beijing 102211, China
Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment
Chang-sheng Li1, Bin-zhou Li2, Xin Jin1, Yu Wang1
1 State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, Liaoning, China; 2 Ansteel Group, Ansteel Beijing Research Institute, Beijing 102211, China
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 °C for 2 h. Cryogenic treatment samples were quenched, cryogenically treated at - 80 and - 196 °C for 4 h, slowly returned to room temperature and thereafter tempered at 180 °C for 2 h, and finally tempered at 180 °C 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%.
Abstract：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 °C for 2 h. Cryogenic treatment samples were quenched, cryogenically treated at - 80 and - 196 °C for 4 h, slowly returned to room temperature and thereafter tempered at 180 °C for 2 h, and finally tempered at 180 °C 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%.
Chang-sheng Li,Bin-zhou Li,Xin Jin, et al. Microstructure and mechanical properties in core of a carburizing 20CrNi2MoV bearing steel subjected to cryogenic treatment[J]. Journal of Iron and Steel Research International, 2021, 28(03): 360-369.
2021, Vol. 28 
