锥形弹簧垫片断裂失效分析

Fracture Analysis of Conical Spring Washer

通过观察锥形弹簧垫片的断裂位置与断口形貌,结合金相组织、化学成分、显微硬度等试验结果,确定该垫片的断裂类型为低应力疲劳断裂。断裂原因为外圆光亮带较小和外圆面粗糙,它们分别由冲裁间隙过大引起和冲压成型后表面修复不充分造成。它们形成严重的微区应力集中,在动载荷的作用下萌生微裂纹,导致疲劳断裂。

Through observing the fracture position and fracture morphology of conical spring washer, combined with the test results of microstrtucture, chemical composition and microhardness, it is determined that the fracture type of the washer is low stress fatigue fiacture. The fracture reasons are the smaller euphoric zone and the larger roughness of the external cylindrical surface, which are caused by larger blanking clearance and insufficient surface restoring after the stamping forming respectively. They form serious micro area stress concentration, then micro-cracks produce and lead to fatigue fracture under the dynamic load.