A fully 3D finite element simulation of cold pilgering

Abstract Cold pilgering is a quite complex tube forming operation, highly non steady state, where the metal undergoes a long series of small incremental deformations resulting in both diameter and thickness reduction. A simplified model, based on the slab method, has been built and used in the last few years [1]. In the present paper, we apply our 3D finite element software Forge3 to analyse one forward stroke (the elementary part of the process) of a cold pilgering operation. The main purpose of the present study is to check the hypotheses and the results of the simplified model, which is used routinely. Strain curves compare well, which is important: the simplified model is based upon an estimation of incremental strain components. Comparison of force-displacement curves show some discrepancies partly due to too coarse a discretisation. Torque, which could never be obtained in our previous studies, either experimentally of by the simplified model, is computed here. Stress maps at various locations are presented. For some of theses data, the effect of varying the difference of friction between the tube/mandrel and tube/die interfaces is described.