20CrMnMo钢齿轮开裂原因分析

Analysis on Cause of 20CrMnMo Steel Gear Cracking

经过渗碳、淬火、回火及再次高频感应淬火和回火的20CrMnMo钢齿轮,在磨削后发现齿面有纵向裂纹。对开裂的齿轮进行了化学成分分析、金相检验和硬度测定,以揭示其开裂的原因。结果表明:齿轮高频感应淬火后的回火不充分因而残余应力较大,且磨削工艺不当,导致齿面磨削烧伤。正是这两个因素导致齿轮表面产生磨削裂纹。

The 20 CrMnMo steel gear, subjected to carburizing, hardening, tempering and then high-frequency induction hardening and tempering again, exhibited longitudinal cracks on its tooth surface after grinding. The chemical composition analysis, metallographic examination and hardness measurements were performed for the cracked gear to discover the cause of its cracking. The results showed that the gear did not be sufficiently tempered after high-frequency induction hardening and therefore had larger residual stress, and the tooth surface displayed grinding burn due to fault in grinding practice. It was these two factors that resulted in formation of grinding cracks on the surface of the gear.