高强度螺栓断裂原因分析

表面磷化处理的高强度螺栓在装配时发生断裂。对断裂螺栓进行宏观和微观检验、化学成分分析、金相检验、能谱分析和力学性能分析。结果表明：该螺栓的裂纹表面有氧化物且存在与螺栓表面相似的磷化物，裂纹处没有脱碳现象，说明裂纹在磷化处理前已存在，判断该裂纹是淬火裂纹。螺栓的断裂是由淬火裂纹造成的。

Fracture Analysis on High Strength Blot

The parkerizing high strength blot fractured during assembly.The analysis on macro and micro,chemical composition,metallographic,EDAS and mechanical property were carried out on the fractured blot.The results showed that the crack surface of blot was oxidized and phosphate similar with bolt surface existed on the crack surface,and there was no decarbonization layer on crack,which showed that the crack existed before parkerizing,so the crack was quenching crack.The bolt fractured was caused by quenching crac...