车轮径向疲劳试验中高强螺栓断裂原因分析

Fracture Analysis of High Strength Bolt in Wheel Radial Fatigue Test

短双扁高强螺栓在车轮径向疲劳试验过程中,出现多根不同程度断裂现象。通过疲劳断裂机理和对失效螺栓进行宏观检验、化学成分分析、力学性能试验、金相检验等方法,分析螺栓断裂的原因,发现晶体夹杂物、热处理不当、螺栓安装预紧力过小等,造成螺栓表面部分区域强度和疲劳下降,出现应力裂纹,最终导致疲劳断裂失效。

During the wheel radial fatigue test,several high strength bolts fractured in different degrees.Through the fatigue fracture mechanism and macro inspection,chemical composition analysis,mechanical property test,metallographic examination and other methods,the causes of bolt fracture are analyzed.It is found that crystal inclusions,improper heat treatment and inadequate pre-tightening force of bolt installation cause the strength and fatigue of some areas on the bolt surface decrease,and stress cracks appear,which will lead to fatigue fracture failure.