Viscoplastic behaviour of steels during welding

Abstract

In most numerical simulations of welding, viscoplastic phenomena are neglected, because of shortness of the process. The aim of this paper is to accurately assess the effect of such phenomena upon predicted residual stresses and distortions, through comparison of simulations using both elastic–plastic and elastic–viscoplastic constitutive laws, and experiments. These experiments are performed on a mock-up developed at INSA Lyon and especially designed for the study of the material behaviour in the heat affected zone of a welded component; this mock-up is sufficiently simple to allow for cheap 2D axisymmetric simulations, but nevertheless complex enough to represent a real welded structure, albeit in a schematic way. It is found that incorporation of viscous effects into the description of the material behaviour has a marginal influence upon predicted residual stresses but a significant one upon predicted residual distortions, which agree much better with measured ones when viscous effects are accounted for.