【摘要】 对断裂失效的螺栓件进行宏观分析、化学成分分析、力学性能试验、断口分析、金相分析和硬度测试,结果表明,该螺栓属于起裂螺纹根部表面的单向弯曲疲劳断裂,断裂螺栓起裂区断口为穿晶和少量沿晶混合的疲劳断口,扩展区断口为穿晶疲劳断口,终断区很窄,为韧窝断口,说明螺栓起裂过程除受到弯曲疲劳应力外,还受到氢的作用,螺栓终断时弯曲应力并不大。螺栓镀锌后残留氢偏高和工作中存在振动是导致螺栓发生疲劳断裂的主要原因。更多还原

【Abstract】 A broken bolt was analyzed by macro analysis, chemical composition analysis, mechanical properties testing,fracture analysis, metallographic analysis and hardness testing, the results show that the bolt is unidirectional bending fatigue fracture at surface of thread boot. It is mix fracture of transcrystalline and a few intergranular rupture in initiation zone. In extension zone it is transcrystalline fatigue fracture. The bolt splitting process is influenced by the bending fatigue stress and hydrogen, the bending stress is slight when the bolt broken. The main reasons for bolt fatigue rupture are higher remain H after zinc plating and vibration in working process.更多还原