Study of effect of different shielding gases in welding AISI 304L materials using automated GTAW machine

In Gas Tungsten Arc (GTA) welding, shielding gas plays an important role in ensuring quality of welds. The selection of the shielding gas is based on kind of material to be welded. The composition of a shielding gas mixture used in GTAW process depends mostly on the chemical and metallurgical interaction between the shielding gas and the molten pool that occur during welding. The chemical interaction of the shielding gas with the molten pool has a marginal influence in the depth of penetration. The depth of penetration, mechanical properties such as Ultimate Tensile Strength, Yield Strength, and Percentage of elongation, Hardness and metallurgical micro structures in all three cases were evaluated in this study. The welding cost for these three cases were also calculated and it is found that use of shielding gas with 2 % Hydrogen + 98% Argon gives the minimum welding cost. Hex-cans of Dummy Fuel Sub Assemblies (DFSA) were fabricated from 3mm thick SS 304L sheets by forming and long seam welding. For DFSA, totally 800 meters weld length was successfully completed using Automated Gas Tungsten Machine with shielding gas mixture of 2 % Hydrogen + 98% Argon. This paper highlights the effect of three different shielding gases in welding of 3mm thick SS 304L material and welding of Hex-Cans for DFSA