[en] An analytical technique to study the thermomechanical response of pipes during welding and subsequent to welding is presented. The numerical simulation was performed using STEALTH, a two-dimensional explicit-finite difference code. A finite difference grid was designed to represent the weld region and a portion of a long, 4-in. diameter butt-welded pipe. The thermal and temperature-dependent mechanical properties of Type 304 stainless steel were used bor both the pipe and the weldment materials. The welding area was subdivided into seven regions. The model for spatial and temporal heat deposition was compatible with the welding speed and conditions reported in relevant G.E. Reports. Since creep is not included, the residual stresses after cooling depend only on the stress-strain path and not on the total time inolved. Therefore, the excess heat in the grid at late times could be withdrawn artificially. This was done by a prescription that smoothly reduced the temperature gradients to achieve ambient conditions. Because the thermal and mechanical responses were computed simultaneously, it was desirable to reduce the disparity between the associated thermal time step and the mechanical time step (based on sound speed). This was achieved by increasing the mechanical time step by employing a density scaling factor of 7.58x10¹¹ to make the two time steps similar. A dynamic relaxation technique was then used to damp the non-physical mechanical oscillations that were generated by the thermal expansions and contractions