列车车轮辐板断裂原因分析

Analysis on Fracture Reason of Railway Wheel Plate

通过化学成分分析、宏观及微观检验、力学性能测试、有限元分析等方法对列车车轮辐板断裂的原因进行了分析。结果表明:车轮辐板内侧面存在明显的点腐蚀,在辐板表面交变应力的作用下发生疲劳开裂,当疲劳裂纹扩展到一定长度时车轮发生断裂。点腐蚀不仅破坏了辐板表面喷丸加工所形成的高硬度残余压应力层,并在点蚀坑内部造成应力集中,形成疲劳裂纹源。因此车轮在运输、存放及使用过程中应注意防护,避免腐蚀的发生。

The fracture reason of railway wheel plate was analyzed by means of chemical composition analysis,macro and micro observation,mechanical property testing,finite element analysis and so on.The results showed that fatigue cracking originated from corrosion pit existed on the inner surface of wheel plate under alternative stress.The wheel plate was broken once the fatigue crack grown to a certain size during service.Corrosion pits did not only induce local stress concentration at the bottom of pits,but also destroy the plate surface layer with high hardness and high residual compressive stress induced by shot peening.The pitting corrosion would decrease the fatigue limit and result in fatigue cracking on the wheel plate.Therefore,the wheels need to be well protected from corrosion during transport,storage and usage.