Multi-response optimization and machinability research of forging and heat treatment parameters in piston production

In this study, the effect of sulfur content of the material, forging temperature, quenching medium, tempering temperature and cooling rate on mechanical properties and machinability in forged DIN42CrMoS4 steel used as engine part were investigated. Hardness measurements, Charpy V notch impact tests and tensile tests were performed to determine the mechanical properties of the investigated pistons. The effects of forging parameters on machinability were analyzed by evaluating the cutting forces. The cutting force measurements were applied with a Kistler piezoelectric drill dynamometer and amplifier. The response surface method (RSM) was carried out to evaluate the results of the experiments and to reveal the relationship between them. The accuracy of the model based on the ANOVA tables was investigated, and regression equations were obtained. A multi-response optimization was performed to optimize forging and heat treatment parameters for minimum cutting force and optimum mechanical properties.