水泥选粉机40CrMoA钢轴断裂原因

Fracture reason of 40CrMoA steel shaft of cement separator

某水泥选粉机40CrMoA钢轴在服役10 d后出现断裂事故,采用宏观观察、化学成分分析、力学性能测试、金相检验等方法对其断裂原因进行分析。结果表明:钢轴显微组织为回火索氏体+条状或块状铁素体,组织中存在硫化物等非金属夹杂物和带状组织,夹杂物和带状组织处容易产生应力集中;裂纹在缺陷处萌生并扩展,最终导致钢轴断裂。

The 40CrMoA steel shaft of a cement separator fractured after 10 days of service.The fracture causes were analyzed by means of macroscopic observation,chemical composition analysis,mechanical property test and metallographic examination.The results show that the microstructure of the steel shaft was tempered sorbite+strip or block ferrite.There were non-metallic inclusions such as sulfide and banded structure in the microstructure,which was easy to produce stress concentration at the inclusions and banded structure.The crack initiated and propagated at the defect,eventually leading to the fracture of the steel shaft.