铝合金活塞板断裂失效分析

Failure Analysis of Fractureon Piston Plate

某活塞气动执行机构失效的原因为铝合金活塞板断裂。采用宏观观察、金相组织观察、化学成分分析及扫描电镜分析等方法,对出现断裂的活塞板进行了失效原因分析。结果表明,活塞板的开裂为疲劳破坏,密封槽底部存在严重的应力集中,且由于使用高强的7A19铝合金,在交变载荷作用下最终导致活塞板断裂。综合评定后,选用5083铝合金,通过适当工艺改进,使活塞板寿命明显提高。

A failure of piston pneumatic actuator was observed,which was caused by the fracture of the piston plate.In order to understand the cause for the fracture of piston plate in this batch,the failure analysis of coupling in each case was performed by microstructure observation,chemical composition analysis,scanning electron microscopic analysis.The results show that the fracture of piston plate in this batch belongs to fatigue fracture,which are caused by serious stress concentration existed at the bottom of sealing groove.Meanwhile,a higher strength aluminum alloy 7A19 was used which accelerated the fatigue cracking.Through selecting 5083 alloy,service life of piston plate was improved greatly with technological modification.