S45C-A电机转轴疲劳试验断裂原因分析及其应对措施

Analysis on the cause of fracture of the rotating shaft of S45C-A motor in the process of fatigue test and its countermeasures

某S45C-A电机转轴在进行疲劳试验的过程中发生断裂。通过宏观形貌分析、金相显微组织分析、化学成分分析及扫描电镜微观形貌分析等方法,对发生断裂的转轴试样进行了失效原因分析。分析结果表明:转轴断裂是由表面擦伤引起的疲劳断裂,表面擦伤属于零件表面微动磨损的一种。预防零件表面微动磨损,首先要对零件连接部位加强紧配合,使之不出现微振,其次是在零件连接部位填充润滑油等隔离接触表面。

The rotating shaft of a S45C-A motor was broken in the process of fatigue test,the causes of which were studied by the methods such as macroscopic morphology analysis,metallographic microstructure analysis,chemical composition analysis and scanning electron microscope(SEM)microscopic morphology analysis.The results showed:the fracture was a kind of fatigue fracture caused by surface scratch,which was a kind of fretting wears on the surface of parts.In order to avoid fretting wears on the surface of parts,firstly,the tight fit at the joint between connecting parts must be strengthened to avoid micro-vibration.Secondly,lubricating oil should be placed at the joint to separate contact surfaces.