深冷处理时间对M2高速钢红硬性的影响

使用洛氏硬度计、X射线衍射仪、扫描电子显微镜和透射电子显微镜等手段研究了深冷处理时间对M2高速钢的硬度和红硬性的影响及其机理.结果表明:深冷处理提高了M2钢的室温硬度和红硬性,深冷12h使650℃红硬性的改善最显著.随着深冷时间的延长残余奥氏体含量不断降低,其形貌由长条形块状转变为薄膜状分布在马氏体板条间;马氏体轴比和...

Effect of Deep Cryogenic Treatment Time on Red Hardness of M2 High Speed Steel

The effect of deep cryogenic treatment time on the room temperature hardness and red hardness of M2 high speed steel was investigated by means of Rockwell hardness tester, X-ray diffractometer, scanning electron microscope and transmission electron microscope. The results show that the room-temperature hardness and red hardness of M2 steel were improved by deep cryogenic treatment, and the red hardness at 650℃ was improved most significantly after deep cryogenic treatment for 12 hours. With the increasing deep cryogenic time, the amount of retained austenite decreased, the shape of retained austenite between martensitic laths changed from strip-like to film-like, the axial ratio and carbon content of martensite decreased gradually, and twin martensite was thinned; the segregation of primary carbides alleviated, and the amount of secondary carbides increased. The increase in the amount of secondary carbides can enhance the precipitation strengthening, and inhibit the decomposition of martensite at high temperatures. In addition, the further transformation of retained austenite to martensite and the thinning of twin martensite also favor the enhancement of room-temperature hardness and red hardness.