Optimization of Forged 42CrMo4 Steel Piston Pin Hole Profile Using Finite Element Method

The fatigue failure of the piston pin hole is considered as a key factor affecting the service life of engines. In this work, the piston pin hole profile was designed as tapered shape following a power law. By combining finite element analysis and hydraulic pulsating fatigue tests, the pin hole profile was optimized. It has been found that the maximum contact pressure on the pin hole surface was reduced by 16,7% with appropriate increasing the radius enlarging rate of the piston pin hole, the maximum tensile stress of the piston pin seat was reduced by 13,1%, and the piston pin seat fatigue safety factor was increased by 41,4%, the piston pin hole fatigue safety factor was increased by 15,9%. The piston pin hole's hydraulic pulsating fatigue test results were found to be consistent with the FEA results. It could be concluded that appropriate increasing the radius enlarging rate of the pin hole could significantly weaken the fatigue wear of the pin hole, further improving its fatigue resistance.