EVALUATING SPOT WELDS OF DISSIMILAR METALS VIA INTEGRATED MECHANICAL TESTING AND FINITE ELEMENT MODELING

This study investigates resistance spot welding of dissimilar materials, namely 37.2 ‎carbon steel, ‎‎304 stainless steel, and commercial aluminium. The effect of welding ‎parameters on nugget ‎growth, tensile shear strength, and failure modes in various ‎material combinations was ‎investigated using a combined experimental and finite element ‎modeling (FEM) approach. ‎Experimental studies included a welding current range (5-15 ‎kA) and time range (10-30 cycles), ‎complemented by tensile testing and hardness ‎measurements. It was observed that Carbon ‎Steel-Stainless Steel (CS-SS) joints ‎achieved the highest strength (9.5 kN at 9 kA), while ‎aluminium-containing joints ‎exhibited lower strengths but required higher optimal currents. ‎Hardness profiles showed ‎extensive variations across weld zones, particularly for aluminium-‎steel joints. Failure mode ‎analysis showed a prevalence of pullout failures for CS-SS joints, in ‎contrast to more ‎interfacial failures in aluminium-steel combinations. A finite element model was ‎developed ‎and validated against experimental data, showing excellent predictive capability for ‎nugget ‎size and joint strength (R²>0.96). This study contributes to the development of ‎dissimilar ‎material welding by providing new insights into parameter optimization, failure ‎‎mechanisms, and industrial application, particularly for automotive and aerospace ‎industries.‎