铁路货车补焊前从板断裂分析

Fracture analysis offront follower plate of freight train by repair welding

为保证铁路货车车钩缓冲装置前从板的安全性,用EDS能谱、金相分析、力学性能测试等手段,探讨前从板断裂原因。结果表明:由不合格焊补修复工艺造成焊缝魏氏组织严重,在冲击载荷作用下从板表面焊缝组织萌生裂纹,裂纹沿先共析柱状铁素体扩展,到一定程度后到达从板,大载荷条件下瞬间断裂。

To ensure the safety of couple buffer device of the freight train when the front follower plate breaks,the fracture reason of the front follower plate was analyzed by means of EDS energy spectrum,metallographic analysis,mechanical property test and so on.The results show that lots of the widmanstatten structure in the weld structure form due to the unqualified repair process;under the impact load,the cracks initiate from the weld structure of the plate surface,and then the cracks propagate along the first pro-eutectoid columnar ferrite,and reach the plate matrix after a certain degree.The instantaneous fracture occurs under large load conditions.