Fracture analysis of crankshaft of heavy truck engine

The crankshaft of diesel engine of a heavy duty vehicle broke during running. By means of macroscopic and microscopic observation of the fracture, chemical composition and metallographic structure analysis, and mechanical property test, the cause of the fracture of the crankshaft was studied. The results showed that the surface hardness of the journal was not up to standard, the wear and tear were serious, and local burns were suffered. The fatigue brittle fracture of crankshaft shaft journal and connecting rod was caused by abnormal external force. It is suggested to control the heat treatment and manufacturing process of crankshaft, optimize the structural design, improve the assembly precision and improve the lubrication system