Residual Stresses and Their Redistribution During Annealing of a Girth-Butt Welded Thin-Walled Pipe

The redistribution of calculated welding stresses during different post weld heat treatments (PWHT) is numerically investigated for a girth-butt welded thin-walled pipe made of a micro-alloyed carbon manganese steel. A finite element analysis with assumed rotational symmetry is performed. The influence of creep, relaxation and phase transformations is included. The amount of stress reduction is found to be mainly controlled by the holding temperature. Most of this reduction was observed to occur during the end of the heating period where the transient stresses followed the fall of the yield stress with temperature.