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
• 来源期刊: 钢铁研究学报（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: ORIGINAL PAPERS
• 页码范围: 360-369
• 页数: 10页
• 语种: 英文

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％.