International Journal of Scientific Research and Engineering Development

Dissimilar welding of austenitic stainless steel (SS 304) and mild steel (E 250A) is increasingly demanded in industries such as automotive, construction, and petrochemical manufacturing to leverage the corrosion resistance of stainless steel alongside the costeffectiveness of mild steel. However, this combination presents significant challenges due to differences in thermal properties, coefficients of thermal expansion, and the potential formation of brittle intermetallic phases. This study presents a comparative analysis of three advanced welding techniques—Gas Tungsten Arc Welding (GTAW), Laser Beam Welding (LBW), and Friction Stir Welding (FSW)—for fabricating dissimilar joints between SS 304 and E 250A plates. The research evaluates and compares the weldments based on mechanical properties (tensile strength, microhardness, and 3 point bend), microstructural characteristics (grain refinement, and heat-affected zone morphology), and Non-Destructive Test (dye penetrant test). While GTAW, often with ER309L filler, offers good control and has been shown to benefit from post-weld heat treatment to relieve residual stresses, it inherently involves significant thermal input . LBW provides a high-power-density alternative with a narrow heat-affected zone, though its performance is highly sensitive to process parameters . In contrast, FSW, a solid-state process, mitigates issues related to solidification and can produce ultra-refined microstructures that enhance mechanical performance. The findings aim to identify the FSW technique that balances joint integrity, process efficiency, and economic feasibility, offering crucial insights for selecting appropriate welding methods for hybrid material assemblies in structural and high-integrity applications.

Rachakonda Benarji, Smt. Ms K Tejaswi,"Comparative Analysis of GTAW, LBW, and FSW Welding Techniques for Dissimilar Weld Joints of SS 304 and Mild Steel (E 250A) Plates" International Journal of Scientific Research and Engineering Development, V9(2): Page(717-733) Mar-Apr 2026. ISSN: 2581-7175. www.ijsred.com. Published by Scientific and Academic Research Publishing.