Effect of Different Shielding Gases on the Metallurgical and Mechanical Properties of Double‐Pulse Metal Inert Gas‐Welded SS 304H

This study seeks to analyze the impact of various shielding gas compositions on the mechanical properties of stainless steel 304 H plates joined using the double pulse metal inert gas process. The investigation focuses on three shielding gases—100% CO 2 , 100% argon, and a mixture of 80% argon with 20% CO 2 —and their influence on the overall weld quality. Depth of penetration, bead width, tensile strength (TS), and impact toughness, are used to assess weld quality. Microstructural analysis is done using electron backscatter diffraction (EBSD), scanning electron microscopy, and energy dispersive spectroscopy. The study reveals that using 100% CO 2 as the shielding gas results in a significant increase in TS, ≈21% higher than the base material. The microstructures at the weld centers and interfaces exhibit a combination of columnar dendrites and equiaxed grains. EBSD analysis indicates a high percentage of high‐angle grain boundaries in the weld center, interface, and heat‐affected zone. It is also noted that, irrespective of the shielding gases used, the ferrite fractions in the welds are restricted to below 5%.