高温预回火对4Cr5MoSiV1Ti模具钢冲击韧性的影响

Influence of high temperature pretempering on impact toughness of 4Cr5MoSiV1Ti die steel

通过洛氏硬度计、万能拉伸试验机与光学显微镜(OM)、扫描电子显微镜(SEM)等分析,研究了高温预回火对4Cr5MoSiV1Ti模具钢冲击韧性的影响。结果表明:高温预回火条件下材料的金相组织为回火马氏体+碳化物,常规回火的组织为回火马氏体;与常规回火工艺相比,材料的抗拉强度基本不变,硬度与屈服强度略有下降,但仍符合使用要求;高温预回火材料的断面收缩率为49.2%,常规回火工艺的断面收缩率为43.4%,提升5.8%;高温预回火材料的冲击韧性为32.66 J/cm^-2,常规回火冲击韧性为27.5 J/cm^-2,提升约18.8%。

Through the Rockwell hardness tester, universal tensile testing machine and optical microscope(OM), scanning electron microscope(SEM) and other analysis methods, the high temperature tempering on 4 Cr5 MoSiV1 Ti steel impact toughness was studied. The results showed that the microstructure of materials at high temperature tempered condition were the pretempered martensite+carbide, the conventional tempering tempered martensite;compared with the conventional tempering process, the tensile strength of the material was basically unchanged, and the hardness and yield strength were slightly decreased, but still met the usage requirements. The reduction rate of cross section was 49.2% under high temperature pre-tempering and 43.4% under conventional tempering process, which increased by 5.8%. The impact toughness of the materials was 32.66 J/cm^-2 under high temperature pre-tempering condition and 27.5 J/cm^-2 under conventional tempering condition, which increased by about 18.8%.