拖拉机电机冷却水管疲劳断裂失效分析

Failure Analysis Fracture of Motor Cooling Water Pipe of Agricultural Tractor

拖拉机的电机冷却水管路由不锈钢管与铝制电机壳体通过过盈配合技术压制而成,在振动实验过程中,冷却水管在水管与壳体连接处发生断裂。为了保障行驶安全,采用宏观形貌分析、化学成分分析、金相显微组织分析、显微硬度测试、SEM微观形貌分析、EDS微区化学成分分析等方法,对发生断裂的电机冷却水管进行了失效原因分析。结果表明:弯管加工过程中芯棒与弯管接触处有不均匀形变,加工划痕导致了断裂区的疲劳断裂。针对分析结果,建议加强对水管生产过程的优化,并对弯管和后续热处理提出改进措施。

The motor cooling water pipe of the tractor is made of stainless steel pipe and aluminum motor shell by interference fit technology.In the process of vibration test,the cooling water pipe breaks at the connection between the water pipe and the shell.In order to ensure driving safety,the failure reasons of the broken cooling water pipe were analyzed by means of macro morphology analysis,chemical composition analysis,metallographic microstructure analysis,microhardness test,SEM micro morphology analysis,EDS microchemical composition analysis,etc.The results show that there is non-uniform deformation in the contact between mandrel and elbow during bending process,and the machining scratches lead to fatigue fracture in the fracture zone.According to the analysis results,it is suggested to strengthen the optimization of water pipe production process,and the improvement measures for the bending and subsequent heat treatment are put forward.