Creep−Fatigue Life Prediction Method of Gray Cast Iron Pistons for Diesel Engines

To solve the failure problems of diesel engine ductile iron pistons caused by the high temperature, high pressure and periodic thermal−mechanical loads during operation, a method combining experimental testing and numerical simulation was adopted to conduct temperature field tests and material creep−fatigue life tests on the ductile iron piston, with a certain diesel engine ductile iron piston taken as the object. A heat transfer numerical model for the ductile iron piston was established and calibrated. The temperature field, thermal stress and thermal−mechanical coupling stress of the piston under the rated condition and the maximum torque condition were analyzed. The lifespan of the ductile iron piston under creep−fatigue damage was evaluated. The results show that the maximum creep−fatigue damage of the ductile iron piston under cyclic loads of rated conditions and maximum torque conditions is 0.21, and the creep−fatigue life is 1 064 times, and failure position is located in the combustion chamber cavity of the piston.