【摘要】 应用光学金相显微镜、透射电镜、洛氏硬度计对P20塑料模具钢进行了显微组织观察和硬度测定 研究了其在不同回火热处理工艺下得到的不同回火组织 (粒状贝氏体回火组织和马氏体回火组织 )及其硬度的变化规律 ,并分析了它们的异同 结果发现 ,回火热处理工艺对粒状贝氏体和马氏体的影响类似 ,只是粒状贝氏体的抗回火性能比马氏体高 650℃回火时 , 2种组织及硬度差别不大 ,且能满足塑料模具钢的使用硬度要求更多还原

【Abstract】 The microstructure was analyzed by the optical microscope,the transmission electron microscope(TEM),and the hardness was measured by the HRC sclerometre.The changing rule of the tempered microstructure (the tempered microstructure of granular bainite and martensite) and the hardness of P20 steel in different heat treatment processes was studied,and the similarities and differences of the two kinds of microstructure and their hardness were compared.The result shows the effect of the tempered heat treatment process on granular bainite and martensite is similar,but the ability of resisting temper of granular bainite is bigger than that of martensite.There is a little difference between two kinds of microstructure and between their hardness and the requirement of the hardness of plastic die steel can be satisfied when P20 steel is tempered at 650 ℃更多还原