PTA浆料输送泵泵轴断裂原因分析

Failure analysis of pump shaft of a PTA slurry conveying pump

叶轮经修复的精对苯二甲酸(PTA)浆料输送泵的泵轴在工作一段时间后于键槽端部发生断裂。通过断口宏观和微观形貌观察、化学成分分析、显微组织观察和力学性能测试等方法,对该泵轴的断裂原因进行分析。结果表明:该泵轴的断裂原因为疲劳断裂。由于修复后的叶轮跳动较大,引起叶轮与泵轴之间的连接键震动,反复挤压导致键槽侧壁萌生微裂纹,材料的塑性很差导致在循环应力作用下疲劳裂纹快速扩展,最终导致脆性断裂。

The pump shaft of a PTA slurry pump fractured at the end of the key groove after working for a period of time after the impeller of the pump was repaired.The fracture reason of the pump shaft was analyzed by macroscopic and microscopic observation,chemical composition analysis,microstructure observation and mechanical property test.The results show that the fracture reason of the pump shaft is fatigue fracture.Due to the large jump of the repaired impeller,the vibration of the connection key between the impeller and the pump shaft is caused.Repeated extrusion leads to micro cracks in the side wall of the key groove.The poor plasticity of the material led to the rapid propagation of fatigue cracks under cyclic stress,and finally leads to brittle fracture.