Numerical assessment of residual stresses induced by combining turning-burnishing (CoTuB) process of AISI 4140 steel using 3D simulation based on a mixed approach

The "combined turning-burnishing" ("CoTuB") process is a new methodology to perform both machining and finishing operations simultaneously. The improved surface integrity and reduction in manufacturing time and cost are the main advantages of this technique. The purpose of this paper is to develop a numerical model for combined cutting and burnishing operation, thus explaining the underlying physical phenomenon. The cutting operation is modelled using a new concept named as the "mixed approach". It consists of replacing the cutting tool by an equivalent thermo-mechanical loading applied on the external surface of the workpiece. It is possible to simulate the CoTuB process using the mixed approach combined with the burnishing ball. The residual stress from the numerical simulation was compared with the experimental results measured by the X-ray diffraction. The 2D model gave a better prediction of the residual stress in the feed direction than in the burnishing direction, whereas the 3D configuration provided a good prediction of the residual stress in both feed and burnishing directions. The developed numerical models gave qualitatively good results of the residual stress for different conditions of burnishing force and feed rate.