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某厂生产的钢板弹簧在台架疲劳试验中发生早期断裂失效,为了找出其失效原因并制定防止断裂失效的预防措施,通过宏观观察、扫描电镜、金相检验等方法对断裂钢板弹簧进行了失效分析。结果表明:断裂发生在板簧紧固处附近,断口起源于板簧喷丸面;断口区域有明显的贝纹线特征,该断裂属于疲劳断裂;弹簧扁钢局部发生过热,出现组织晶粒粗大和全脱碳等异常组织。通过降低加热温度和减少在加热炉内高温段的停留时间,选择合适的加热速度,并控制炉内气氛等措施,可减少甚至避免热处理过程中局部过热造成的板簧早期断裂失效。
In order to find out the causes of failure and to make preventive measures to prevent the failure, a leaf spring manufactured by a factory occurred early fracture failure in the bench fatigue test. The rupture leaf spring was examined by macro observation, scanning electron microscopy and metallographic examination Failure Analysis. The results show that the fracture occurs near the plate spring and the fracture originates from the plate spring peening surface. The fracture area has the obvious characteristics of shell line and the fracture belongs to the fatigue fracture. The spring flat steel locally overheats and the coarse grains And all decarbonization and other abnormal tissue. By reducing the heating temperature and reducing the residence time in the high temperature section of the furnace, selecting the appropriate heating rate and controlling the atmosphere in the furnace, etc., the early failure of the leaf spring caused by local overheating during the heat treatment can be reduced or avoided.