奥氏体化温度对1.2367热作模具钢显微组织及性能的影响

Effect of austenitizing temperature on microstructure and properties of 1.2367 hot working die steel

通过热力学计算并采用光镜、扫描电镜、X射线衍射仪、洛氏硬度计及冲击试验机等,研究了奥氏体化温度对1.2367热作模具钢显微组织及性能的影响。结果表明,1.2367钢的室温平衡组织为铁素体基体上分布着M_(23)C_(6)、M_(6)C和MC型碳化物,而在1025~1080℃之间淬火时,随着奥氏体化温度的升高碳化物逐渐减少、残留奥氏体量逐渐增加,淬火态组织为马氏体+碳化物+残留奥氏体。在615℃保温2 h两次回火后的组织为回火马氏体+碳化物,随奥氏体化温度的升高,硬度逐渐增加,最高硬度达49.05 HRC,冲击吸收能量逐渐降低。1050℃淬火+615℃回火后,1.2367热作模具钢可获得最佳强韧性匹配。

Effect of austenitizing temperature on microstructure and properties 1.2367 hot working die steel was studied by means of thermodynamic calculation,optical microscope,scanning electron microscope,X-ray diffractometer,Rockwell hardness tester and impact testing machine.The results show that the room temperature equilibrium structure of the 1.2367 steel is distributed with M_(23)C_(6),M_(6)C and MC carbides on the ferrite matrix,while when quenched between 1025℃and 1080℃,the carbide content gradually decreases and the retained austenite content gradually increases with the increase of austenitizing temperature,and the quenched microstructure is martensite+carbides+retained austenite.After twice rounds of tempering at 615 C for 2 h,the microstructure is tempered martensite+carbides,and with the increase of austenitizing temperature,the hardness gradually increases,with the maximum hardness of 49.05 HRC,but the impact absorbed energy gradually reduces.After quenching at 1050℃and tempering at 615℃,the 1.2367 hot working die steel can achieve the best strength and toughness matching.