Thermal mechanical loadings in machining process would promote material microstructure changes. The material microstructure evolution, such as grain size evolution and phase transformation could significantly influence the material flow stress behavior, which will directly affect the machining forces. An analytical model is proposed to predict cutting forces during the turning of AISI 4130 steel. The material dynamic recrystallization is considered through Johnson-Mehl-Avrami-Kolmogorov (JMAK) model. The explicit calculation of average grain size is provided in an analytical model. The grain size effect on the material flow stress is considered by introducing the Hall-Petch relation into a modified Johnson-Cook model. The cutting forces prediction are based on Oxley’s contact mechanics with consideration of mechanical and thermal loads. The model is validated by comparing the predicted machining forces with experimental measurements.
A new approach of predicting dynamic recrystallization using directly a flow stress model and its application to medium Mn steel