Characterization of material strain and thermal softening effects in the cutting process

Abstract

Abstract Accurate descriptions of workpiece behaviors are indispensable for achieving reliable simulations of the cutting process. However, the material plastic constitutive models obtained through conventional material tests do not apply in the ranges of strain and strain rate encountered in the realistic machining processes. To address this issue, in this study, we attempt to develop a methodology to understand and identify the plastic deformation behaviors based on high-speed filming and induction preheating during the cutting tests. Different levels of strain, strain rate, and temperature are realized by varying the rake angle, cutting velocity, and initial workpiece temperature, respectively. The plastic deformation and temperature rise in the primary shear zone are characterized by the fine-scale digital image correlation technique and heat convection–conduction equation, respectively, thus rendering the machining test into a high-dynamic-material testing method. The material exhibits strain softening in the primary shear zone and a reduced thermal softening effect under rapid heating conditions. These initial findings can deepen the understanding of material behaviors during the cutting process and can be further developed for implementation in numerical machining models.