柴油机主连杆断裂原因分析

Fracture Reason Analysis of Master Connecting Rod in Diesel Engine

采用化学分析、扫描电镜观察、力学性能测试和金相检验等方法对断裂的柴油机主连杆进行了分析。结果表明:主连杆的断裂属疲劳断裂;主连杆表层的脱碳层以及表面凹坑、折叠、裂纹等缺陷的存在是导致主连杆疲劳断裂的主要原因;基体组织中铁素体的存在则对疲劳裂纹的扩展起到了促进作用。

The fracture reasons for the master connecting rod in diesel engine were analyzed by chemical analysis,SEM observation,mechanical properties test and metallographic examination.The results show that the fracture of the master connecting rod is due to fatigue fracture.The existence of decarburized layer in the surface of the master connecting rod and the defects such as surface dents,folding and cracks are the main reasons for the fatigue fracture of the master connecting rod.The ferrite in the matrix has promoting effects on the propagation of the fatigue crack.