Prediction of Serrated Chip Formation in Metal Cutting Process by FEM

Abstract

Adiabatic shear bands have been observed in the serrated chip during high strain rate metal cutting process of carbon medium steel. The recent microscopic observations have shown that dynamic recrystallization occurs in the narrow adiabatic shear bands. However the conventional flow stress models in general do not predict the occurrence of dynamic recrystallization in the shear bands and the thermal softening effects accompanied by DRX. In the present study, based on a new flow stress model, we predict the serrated chip formation. The finite element analysis with this proposed flow stress model shows that the temperature of the shear band during cutting process rises to initiate dynamic recrystallization, dynamic recrystallization lowers the flow stress, and that adiabatic shear localized bands and the serrated chips are formed. FEA is also used to predict and compare chip formations of two flow stress models in orthogonal metal cutting with AISI 1045 steel.