齿轮轴齿根部裂纹产生原因分析

某公司生产的齿轮轴齿根部产生裂纹，被怀疑是锻坯质量所致。江苏省产品质量监督检验研究院对齿轮轴齿根部裂纹的进行检验分析。结果表明：裂纹均位于齿根部R角处，呈断续状由外向内发展，裂纹两侧边缘无氧化脱碳现象；在齿轮轴的次表层区域的组织中有部分魏氏组织特征，而心部组织中无魏氏组织存在，表明该齿轮轴齿根部裂纹产生的原因是热处理工艺不当。

Analysis of crack formation at tooth root of gear shaft

Since som cracks occurred at the tooth root of the gear shaft made by a certain company and they were under suspicion of being the stock forging quaulity, the crack formation at tooth root of the gear shaft was analyzed by Jiangsu Provincial Supervising ＆ Testing Research Institute for Products Quality. The analysis re-sult shows that the cracks formed at the R corner of the tooth root are discontinuously propagated inward, there is no oxidation or deearburization beside the cracks, but there is Widmannstatten structure in the subsurface, and there is no Widmannstatten structure at the center of the gear shaft. The conclusion is that the crack forma-tion is due to the improper subsequent heat treatment.