Research on Dynamic Evolution of Residual Stress Based on Simulation of Piston Manufacturing Process

Rather than focusing on the residual stress generated from casting, machining, or heat treatment unilaterally, a comprehensive research method to consider the whole dynamic evolution of residual stress is proposed. The cast iron piston is taken as the research object to establish a continuous simulation model for its manufacturing. Firstly, a simulation model of piston casting is established to analyze the stress change. Subsequently, through the machining and heat treatment simulation of the piston, the variation law of residual stress before and after machining is analyzed. Different process parameters are designed to study the redistribution mechanism of residual stress. Residual stress tests are further conducted on the processed piston products. The results indicate that shakeout can effectively remove 60% to 80% of the residual stress. The removal of materials results in overall residual stress release and redistribution for the piston, and the piston releases 10% to 40% of the residual stress after machining. The heat treatment of the machined piston can effectively reduce the residual stress with a maximum reduction of 27.1%. The good consistency between experimental results and simulation results further confirms the feasibility of the comprehensive research method. This study is beneficial for achieving low stress manufacturing of pistons and improving their working performance.