采用化学成分分析、金相分析、显微硬度测试以及残余应力测定等方法对某20CrMnMo钢渗碳齿轮磨削裂纹产生原因进行了分析。结果表明：该齿轮产生磨削裂纹主要是由于磨削过程中表面产生严重的二次淬火烧伤和回火烧伤, 二次淬火烧伤的次表面及边缘回火烧伤区硬度大幅下降及表面受拉应力, 两者共同作用下产生了磨削裂纹;另外, 渗碳层中存在针状马氏体和大量残余奥氏体, 增加了齿轮磨削开裂的敏感性, 这是齿轮产生磨削裂纹的另一个重要原因。

The forming reasons for grinding cracks of 20CrMnMo steel carburized gears were analyzed by means of chemical composition analysis, metallographic examination, microhardness test and residual stress test. The results show that the main reasons for the grinding cracks were secondary quenching burn and tempering burn on the gear surface during grinding. Grinding cracks were caused by the combined effects of serious decline in hardness and surface tensile stress at the subsurface of the secondary quenching burn area and the edge tempering burn area. Besides, the grinding cracking sensitivity was increased due to the acicular martensite and massive retained austenite existing in the carburized layer, which was also an important reason for the grinding cracks.