马达轴断裂失效分析

Fracture failure analysis of motor shaft

某型重卡的风扇冷却系统的马达,在使用约125小时,车辆行驶3580公里后出现断轴现象,该马达轴的材质为40Cr,采用断口分析、化学成分分析、金相分析等方法对断裂轴进行了分析,结果表明,马达轴断裂的根本原因为渗氮工艺中键槽未做好保护,导致键槽表面渗氮,受力时在键槽底部过渡角应力集中,渗氮层受拉力后起源开裂。

The motor shaft of the fan cooling system for heavy truck was fractured when the truck was performed about 125 hours and3580 kilometers,The material of the motor shaft was 40Cr,Fracture of shaft was analyzed by using fracture analysis,chemical composition and metalgraphic testing and other methods,the results showed that the keyway was not well protected during nitriding process,which was the main cause leading to fracture failure.