Finite element simulation of natural gas pipelines in service welding repair

Abstract This paper mainly studies the welding of annular fillet weld using carbon dioxide gas shielded welding and interrupted pulsed arc welding (IPAW) method, using ABAQUS finite element technology to simulate the in-service welding process of X80 pipeline, and comparatively analyze the carbon dioxide gas shielded welding and IPAW of the priming layer, the overall weld temperature field and the distribution of stress field. The distribution patterns of the priming layer, overall welding temperature field and stress field of carbon dioxide gas shielded welding and IPAW were comparatively analyzed. The results indicate that, in addition to the conventional carbon dioxide gas shielded welding method, improved pulse arc welding (IPAW) is also suitable for welding repair. IPAW can significantly mitigate the adverse effects on the base material during welding. It demonstrates superior performance in controlling thermal effects and stress concentration within the weld zone, resulting in a smaller heat-affected zone compared to that produced by carbon dioxide gas shielded welding, thereby effectively reducing overall residual stress. Through finite element simulation, it is possible to replicate in-service welding conditions, optimize welding process parameters, control heat input, monitor welding residual stress, and provide data-driven support for actual repair welding, ultimately enhancing repair quality.