42CrMoA钢发动机连杆断裂分析

Fracture Analysis of Engine Connecting Rod for 42CrMoA

通过宏观检验及扫描电镜分析、化学成分分析、金相分析等方法,对42CrMoA发动机连杆转动过程中断裂的产生原因进行了分析。结果表明:该发动机连杆在转动过程中断裂现象是调质处理阶段在连杆盖处产生了淬火裂纹。发动机运转时在淬火裂纹处形成了应力集中,在发动机的长时间运转过程中还保持相接的两个边角区域逐步产生了疲劳开裂,并最终导致了连杆盖断裂。

By means of macroscopic inspection,SEM analysis,chemical composition analysis and metallographic analysis,the causes of fracture of 42CrMoA engine connecting rod during rotation are analyzed.The results show that the fracture of the engine connecting rod during rotation is caused by quenching cracks at the connecting rod cover during quenching and tempering treatment,and the stress concentration is formed at the quenching cracks during engine operation,during the long-time operation of the engine,the two edges and corners still connected gradually produce fatigue crack,and finally lead to the fracture of the connecting rod cover.