Low-current TIG arc-assisted high-speed laser welding process for stainless steel plates

To overcome the technical bottleneck that high quality and high efficiency are difficult to simultaneously improve in traditional welding processes of thin stainless steel plates, a low-current TIG arc-assisted high-speed laser welding process was proposed, and the effects of welding process parameters on weld appearance were systematically studied using 1.2 mm thick 409L ferritic stainless steel plates. The results show that when the distance between laser and tungsten electrode is 3 ~ 4 mm, and the welding current is 50 A, the laser and TIG arc generate a strong coupling effect, which can effectively stabilize the arc while achieving low heat input welding, and the welding speed can reach 4~5 m/min. Compared with the TIG welding process, the welding efficiency of this process is improved by 2.8 times; the heat input is reduced by 63.1%, and the formation of undercut and humping weld defects is fundamentally suppressed. This process exhibits wide applicability in the welding of stainless steel plates. For 2.0 mm thick 304 austenitic stainless steel and 409L ferritic stainless steel plates, the welding speeds reach 3.2 m/min and 3.0 m/min, respectively, and the elongations after fracture are 88.9% and 76.4% of those of the base metal, respectively, realizing the high-quality, high-efficiency, and low heat input welding of thin stainless steel plates.