Numerical simulation of thermal and residual stress fields induced by lined pipe welding

This paper investigates numerical thermal fields and residual stresses induced by single-pass weld overlay (lap-weld) and girth welding (butt-weld) in lined pipe using Tungsten Inert Gas (TIG) welding. A distributed power density of the moving heat source based on Goldak's ellipsoid heat flux distribution is used in a Finite Element (FE) simulation of the lined pipe welding process. In addition, radiation and convection have been incorporated in heat transfer coefficient user-subroutines for the FE code ABAQUS. The 3-D FE model approach has been validated using previous experimental results published for butt-welds of similar sections of carbon-manganese C-Mn steel pipe lined with stainless steel. The FE model has been developed to determine the thermal isotherms and residual stress distributions from weld overlay and girth welding. The use of an inner layer known as a liner has a considerable influence on the thermal history and residual stress distributions. Furthermore, the influence of the weld overlay has been examined thermally and mechanically as it is a key factor that can affect the quality of lined pipe welding.