Impact of cutting tool wear on residual stresses induced during turning of a 15-5 PH stainless steel

Abstract

Abstract Finish turning is one of the key operations governing the residual stresses below the machined surface. The residual stress state depends on the cutting conditions and on the selected cutting tool system, i.e. macro geometry, cutting edge preparation as well as tool grade. However, tool wear often affects the interaction between the tool and the workpiece leading to severe modifications of the residual stress state. This work aims at investigating the influence of cutting tool wear on the surface integrity in longitudinal turning of a 15-5PH stainless steel. First, an experimental sensitivity study is performed to assess the effect of various wear modes on the residual stresses. Then a numerical model has been developed to understand the experimental observations and connect them to the thermomechanical loadings and local data within the near surface. The impact on residual stresses of three types of wear were tested (flank face wear, rake face wear and adhesion on the cutting edge) with the same cutting condition (Vc =120m/min, ap = 0.2 mm and f = 0.2 mm.rev-1). Based on the experiment, the numerical simulation proposes to observe the impact of wear on thermomechanical loadings by simulated a tool with a rounded cutting edge, a crater on the rake face and high flank face contact length. It follows that the impact of the rake face wear is extremely low, contrary to the rounded edge or the flank face wear which increased the contact length and significantly impact the loadings.