某钢结构螺栓断裂失效分析

Failure Analysis on Frature of a Bolt for Steel Construction

某公司一户外钢结构楼梯螺栓发生断裂失效,采用宏观分析、化学成分分析、金相分析、硬度测试、断口分析等方法对螺栓断裂原因进行了分析。结果表明:螺栓断裂主要是因为螺栓部分新鲜表面暴露在空气中,在腐蚀性环境和应力的共同作用下,应力集中的螺栓根部开始萌生裂纹,裂纹由外向内扩展,最终造成一次性断裂。

The bolt used in a company＇s outdoor steel construction stair fractured,and means such as macro analysis,chemical composition analysis,metallographic analysis,hardness test and fracture analysis were used to analyze the fracture causes of the bolt.The results show that the fracture of the bolt was mainly due to the fresh surface of the bolt being exposed to the air.Under the combined action of the corrosive environment and stress,cracks initiated at the root of the bolt where the stress was concentrated.The cracks propagated from the outside to the inside and eventually caused a one-time fracture.