起重绳轮失效分析

FAILURE ANALYSIS OF A CRANE SHEAVE

采用光学显微镜和扫描电镜(SEM)等检测方法,对起重设备上的绳轮因沿轮槽槽底分离而失效的原因进行了分析。结果表明,绳轮发生分离是由塞焊金属断裂引起的,而其断裂的原因则是焊接质量不良。同时,塞焊点布局不合理,进而引起匹配面变形,也是引起绳轮失效的原因之一。提出了建议。

A sheave on a crane consisting of two matching components （of hot press formed and joined by a plug weld）, that failed by splitting along the base of the groove while lifting a equipment, was examined using optical and SEM metallographic techniques. The examination indicated that the sheave had been failed by plug weld fracture, which was attributed to poor weld quality. During normal operation of the sheave, the loosing of inadequated plug welds would increase the stress on the remaing welds, until they all tensile overload failed. Small errors in the placement of plug welds was contributing factors in final failure because they resulted in a loss in fit and coving of the matching compments.