Fracture Reason of the Compressor Connecting Rod

Fracture reason of the compressor connecting rod was analyzed by means of macro observation,optical microscope,chemical analysis,mechanical test and fracture analysis. The results show that failure model of the rod was fatigue fracture. The improper heat treatment process resulted in the decrease of yield strength and tensile strength of the rod. Micro-crack initiated at the boot of screw thread because of high stress comcentration during working process,propagated due to cyclic loading and finally caused the fatigue rupture of the rod.