Influence of multi-process parameter linkage on the formation of lack of fusion defects based on SYSWLED simulation analysis

Abstract The lack of fusion defects remains a significant challenge in narrow-gap automatic welding of pipeline circumferential joints and then becomes the primary factor affecting pipeline longevity. The influence of multi-process parameter linkage on the welding temperature field and formation of lack of fusion defects was investigated based on orthogonal experiments and SYSWELD finite element simulation. The results indicated that welding current and speed had the most significant influence on the welding temperature field. At the same time, oscillation width affected the ability to obtain arc temperature on both sides of the weld groove. Oscillation time and edge dwell time determined the duration of arc heating on one side of the groove. A serrated temperature field morphology may occur when the dwell time is too long, leading to a lack of fusion defects. There were interactive effects among various welding parameters. Increasing heat input could reduce the risk of a lack of fusion defects. Besides, a reasonable setting of oscillation width, oscillation time, and edge dwell time could also reduce the formation risk of lack of fusion defects.