Effect of the interpass temperature on the predicted residual stress distributions in a multipass welded piping branch junction

Abstract

A sequentially coupled three‐dimensional thermomechanical finite element model has been developed to predict residual stress distributions in a multipass welded piping branch junction. The residual stresses at the branch and run pipe cross‐sections, as well as along the circumferential weldlines on the outer surfaces of both the run and the branch pipes and on the inner surface of the branch pipe, are predicted. Three levels of interpass temperature have been selected to investigate their effect on the peak residual stresses. It is revealed that the interpass temperature has a significant effect on the residual stresses. As the interpass temperature is increased, both the peak hoop and the axial residual stresses at the run and branch cross‐sections decrease. The peak normal stresses along the circumferential weldline on the outer surface of the run pipes are also reduced. However, increasing the interpass temperature had a negligible effect on the peak tangential residual stresses along the circumferential weld line on the inner surface of the branch pipe. The results presented and the modelling technique described in the current study can be used towards formulating a recommendation to optimize residual stress profiles in multipass welded complex geometries through better interpass temperature control.