42CrMo钢长轴感应淬火裂纹原因分析  

Failure analysis of induction hardening cracks in 42CrMo long shaft

作　　者：陈步超 宋翊 刘海明 陈露 王致远 牛宗冉 鞠玉琳 袁志钟[1] CHEN Buchao;SONG Yi;LIU Haiming;CHEN Lu;WANG Zhiyuan;NIU Zongran;JU Yulin;YUAN Zhizhong(School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China)

机构地区：[1]江苏大学材料科学与工程学院,江苏镇江212013

出　　处：《金属加工（热加工）》2024年第1期76-81,共6页MW Metal Forming

基　　金：国家自然科学基金(52203379)。

摘　　要：观察了感应淬火后42CrMo钢长轴开裂的微观组织、裂纹形貌并测试其化学成分和力学性能,分析了裂纹的形成原因。结果表明:裂纹沿轴向分布且仅存在于大直径区域的淬硬层,与心部相比,该区域晶粒异常粗大且部分晶界熔化,裂纹沿晶扩展,裂纹内存在氧化物,因此判断裂纹产生的主要原因是感应淬火工艺参数不当,导致在长轴直径增大区域的淬火加热温度过高,从而造成淬硬层发生过烧、晶界弱化甚至烧蚀,从而出现裂纹。相比小直径区域,大直径区域的淬硬层较厚、硬度偏低,也佐证了该论断。The microstructure,morphology of cracks,composition and mechanical properties of cracked 42CrMo long shaft after induction quenching were characterized.The causes of the cracks were analyzed.The results show that the longitudinal cracks are found at the hardened layer of the larger diameter region.The grains are abnormally coarse and parts of the grain boundaries are fused compared with those of the center region.Cracks with oxides extends interannually.Therefore,the reason is due to the inappropriate parameters of the induction hardening process for the larger diameter part,which results in the over high quenching temperature,over burned grains and fused grain boundaries and thereafter cracks in the hardened layer.The thicker hardened layer and lower hardness of the larger diameter part compared with those of the smaller diameter part also testify this judgment.

关 键 词：42CRMO钢 沿晶裂纹 感应淬火 夹杂物 过烧 

分 类 号：TG156.3[金属学及工艺—热处理]