热处理工艺对Cr12MoV钢组织及硬度的影响

Effect of heat treatment process on microstructure and hardness of Cr12MoV steel

采用金相显微镜、XRD射线衍射仪及维氏硬度计等,研究了普通热处理和深冷处理工艺对Cr12MoV钢显微组织及硬度的影响。结果表明:Cr12MoV钢经普通热处理和深冷处理淬火后的组织均为隐针马氏体+残余奥氏体+碳化物,200℃低温回火后组织转变为回火马氏体+碳化物+残余奥氏体。深冷处理可大幅减少钢中残余奥氏体,提升钢的硬度;热处理采用1020℃加热保温60 min淬火+(-196℃)深冷2 h+200℃回火保温120 min,硬度(HV30)值最高,可达780。

In this paper the effect of ordinary heat treatment and cryogenic treatment on the microstructure and hardness of Cr12MoV steel had been investigated by microstructure observation using a metallographic microscope,the retained austenite determination by XRD,and the hardness measurement.The results show that the microstructure of Cr12MoV steel after ordinary heat treatment and cryogenic treatment are crypto needle martensite and retained austenite and carbide,and the microstructure changes into tempered martensite and carbide and retained austenite after low temperature tempering at 200℃.Cryogenic treatment can greatly reduce the retained austenite in the steel and improve the hardness.The highest hardness is 780 HV30 when steel are quenched at 1020℃and held for 60 min at-196℃for 2 h and tempered at 200℃for 120 min.