A new approach for the modelling of residual stresses induced by turning of 316L

Residual stresses induced by machining processes like turning play an important role on the lifetime of pieces. Several phenomena are responsible of these distributions: mechanical effects, thermal effects, microstructure modifications and/or a combination of the previous mechanisms. During the last 20 years, a large number of experimental investigations have shown the influence of machining parameters on the distribution of residual stresses, whereas only few works have tried to model the fundamental phenomena. Past works try to model the chip removal process by means of finite element software allowing large strains. Such models are very limited to predict accurately the residual stresses profiles in very narrow affected layers (some micrometers) and are very much CPU time consuming. The key idea presented in this paper consists in disconnecting the chip formation process on one hand and the modelling of the mechanisms leading to the residual stresses on the other hand. Indeed, this approach necessitates quantifying the thermo-mechanical load induced by the cutting tool onto the machined surface. Secondly, a finite-element model simulates the application and the movement of this thermo-mechanical load on to the machined surface so as to predict the residual stresses induced.