Cr12模具钢热处理工艺及强韧性能的研究

Study on Heat Treatment Process and Strength and Toughness of Cr12 Die Steel

采用光学显微镜、扫描电镜、X射线衍射仪、硬度及冲击试验研究了Cr12模具钢一次硬化及二次硬化热处理对强韧性能的影响。结果表明:奥氏体(A)的合金化程度、晶粒度大小以及碳化物状态是影响Cr12钢的硬化及强韧性的主要因素;随淬火温度升高,奥氏体合金化程度增加,能够获得较多的残余奥氏体(AR)同时增加马氏体(M)的抗回火软化能力,但过于粗大的晶粒尺寸会降低材料韧性;高温回火后的二次硬化行为主要由AR→M转变产生,而硬化峰值及其位置还与AR的含量和M的抗回火软化能力有关。

Effects of the first hardening and the secondary hardening heat treatment on strength and toughness of Cr12 die steel were investigated by OM, SEM, XRD, hardness test and impact test. The results show that, alloying extent of austenite （A）, average grain size and carbides state are the main factors affecting the strength and toughness of Cr12 die steel. With the increase of quenching temperature, the alloying extent of austenite increases,which can obtain more retained austenite （AR）, at the same time increase resistance to tempering softening capacity of the martensite （M）. But too coarse grain size will reduce the toughness of the material. The two hardening behavior after high temperature tempering is mainly produced by the transformation from AR to M, and the hardening peak value and its position are also related to the AR content and the resistance to tempering softening of M.