原始组织对42CrMo钢磨削淬硬层的影响

Influence of Original Microstructure on Grind-Hardened Layer of 42CrMo Steel

在MKL7132X6/12数控强力成形磨床上对42CrMo钢进行磨削淬硬加工试验,通过光学显微镜、扫描电镜、显微硬度计等测试仪器测量和分析磨削淬硬层的宏观组织、显微组织、硬度以及淬硬层深度,研究原始组织对42CrMo钢磨削淬硬层组织和硬度的影响。结果表明：完全淬硬层表层由针状马氏体和少量未溶碳化物组成;中间层由略粗针状马氏体和少量未溶碳化物组成;过渡层组织因原始组织而异。原始组织对完全淬硬区组织和硬度无明显影响,显微硬度620~700 HV。但随着工件材料原始组织均匀性的提高,略粗马氏体组织距工件表面的距离变大,且磨削淬硬层深度变大。

The grind-hardening test of 42CrMo steel was carried out on a forming grinding machine. The macro-morphology, microstructures, micro-hardness and the depths of the hardened layer were measured and analyzed by OM, SEM and digital micro-hardness tester. The influences of original structure on the grinding-hardened layer of 42CrMo steel were studied. The results show that the martensite and a small amount of undissolved carbide appear in the surface layer, and slightly coarse martensite and a small amount of undissolved carbide appear in the middle layer of the completely hardened zone. Microstructure of the transition zone varies with the original structure. The microstructures and micro-hardness of the completely hardened zone have no obvious change under different original organizations, and the micro-hardness is 620-700 HV. However, the distance from the slightly coarse martensite and the depth of the hardened layer increase with the uniformity improvement of the original microstructure.