GIS操作机构用止锁凸轮开裂失效分析

Failure Analysis of Locking Cam Used in GIS Operating Mechanism

某单位产品更新换代前,在验证操作机构性能时出现异常报警,经检查发现,该机构止锁凸轮断裂损坏。本文采用宏观断口分析、化学成分分析、硬度检测、金相检验、扫描电镜分析等方法对断裂的原因进行了分析。结果表明:原材料呈带状分布的偏析带,在热处理淬火时极易产生微裂纹;热处理不当破坏了凸轮"外硬内韧"的状态,凸轮整体呈脆性,这两个因素最终造成止锁凸轮发生沿晶脆性断裂。

Before the replacement of unit product,an abnormal alarm occurred when the performance of the operating mechanism was verified,and it was found that the locking cam of the mechanism was broken and damaged.In this pa⁃per,macro fracture analysis,chemical composition analysis,hardness testing,metallographic examination,scanning electron microscope analysis and other methods were used to analyze the causes of fracture.The results show that the raw materials were banded segregation bands,which were easy to produce microcracks during heat treatment and quenching;Improper heat treatment destroys the"hard outside and tough inside"state of the cam,and the whole cam was brittle.These two factors eventually led to intergranular brittle fracture of the locking cam.