3D modelling of multipass welding of a 316L stainless steel pipe

Welding processes induce residual stresses and distortions which can play a major role in the mechanical strength of a component. Numerical simulation of processes is of big help to control these effects as it provides the evolution of physical quantities such as temperature, stresses and strains at any point in the structure. Simulations of single pass welding stresses give today rather satisfying results. Prediction of distortions is far much difficult as it needs 3D simulations to accurately take account of the constraining conditions induced by the weld bead. The difficulty is still increased when considering multipass welding. This paper presents the 3D finite element simulation of multipass welding of a 316L stainless steel pipe. The whole process includes 13 weld passes and the simulation has been achieved using adaptive mesh refinements and a procedure to transport the results between the different meshes. The thermo-mechanical model used as well as the simulation methodology are detailed. Computed distortions and residual stresses are compared with experimental measurements after five passes.