中碳钢锻造卸扣断裂分析

Analysis on Fracture Reasons of the Medium Carbon Steel Forging Shackle

45钢锻造卸扣在使用过程中发生断裂。通过化学成分分析、断口形貌分析、金相检验和力学性能测试等方法对卸扣断裂的原因进行了分析。结果表明:该卸扣表面存在众多的锻造细小折叠裂纹,这些细小折叠裂纹扩展及延伸形成陈旧裂纹,导致卸扣的承载能力下降,当卸扣受到冲击载荷作用,便产生以陈旧裂纹为断裂源的一次脆性断裂。

The forging shackle of 45 steel broke in the process of use.The cause of fracture of shackle was analyzed by means of chemical composition analysis,fracture morphology analysis,metallographic examination and mechanical properties test.The results show that there are many forging small cracks on the surface of the shackle,and the propagation and extension of these small cracks form old cracks,which leads to the decrease of the bearing capacity of the shackle.When the shackle is subjected to the impact load,a brittle fracture with old cracks as the source of fracture occurs.