Effects of Shielding Gases on the Weldability of Laser Welded Austenitic Stainless Steel

Abstract

In laser welding of austenitic stainless steels, shielding gases have great potential for improving the mechanical properties of the welds, suppressing plasma plumes, and stabilizing the keyhole. Previous studies have shown that shielding gases can alter the weld geometry and microstructural constituents of the welds. Disturbances of laser beam absorption by laser-induced plasma can be controlled through shielding gas parameters such as the shielding gas composition, flow rate, and supplying direction. In addition, surface-active elements added to the shielding gas can alter the behavior of the molten pool. In this paper, previous studies are reviewed to assess the shielding gas effects on the characteristics of laser-welded austenitic stainless steel. The activated mechanism of molten pool flow by additional surface tension active elements is also discussed.