某轴承外圈滚道裂纹分析

Cracking analysis of outer ring raceway of bearing

某轴承外圈在试验过程中上侧滚道发生网状开裂和掉片,通过宏观分析、化学成分分析、硬度测试、断口分析以及金相分析等手段,对轴承外圈失效部位进行综合分析。结果表明:上侧滚道可观察到断口呈贝纹线,放射状棱线扩展,疲劳源和碎片表面存在磨削白亮层和磨削回火层,白亮层和回火层为磨削过程中的磨削工艺不当所导致,磨削白亮层和磨削回火层的存在严重影响零件的接触疲劳性能,零件在次表面发生疲劳萌生和扩展,导致轴承外圈在较短的时间内疲劳失效。

Mesh cracking and spalling were found on a bearing outer ring raceway during the testing.The failure parts of the bearing were comprehensively analyzed by the means of macroscopic analysis,chemical composition analysis,hardness test,fracture analysis and metallographic analysis.The results showed that the fracture was characterized by shell lines and the blade ridge line extend radially.Otherwise,there were grinding white layer and tempering layer on the upper side raceway surface,which were caused by improper grinding process and seriously affected the contact fatigue performance of the parts.The fatigue initiation and expansion of the parts on the secondary surface led to the fatigue failure of the outer ring of the bearing in a short time.