Process Optimization in Resistance Spot Welding for Enhanced Weld Quality and Energy-Efficient Steel Joining

This study investigates the optimization of resistance spot welding (RSW) parameters to improve weld quality and reduce energy consumption in the joining of SPSC 440 steel sheets, a material commonly used in automotive part manufacturing. The experimental work focused on 1.6 mm thick sheets and examined the effects of electrode material, welding current, clamping force, and holding time across 18 controlled trials using an industrial-grade RSW machine. Weld strength was assessed by using a universal tensile testing machine, while weld morphology was evaluated through optical microscopy. Analysis of variance (ANOVA) and signal-to-noise (S/N) ratio analysis revealed that welding current is the dominant factor influencing both energy input and nugget formation. Electrode material, particularly the Z-Trode type, was found to have the most significant impact on mechanical performance and weld appearance, producing stronger joints with reduced surface defects. Beyond mechanical strength, weld quality was also evaluated based on consistency, spatter minimization, and nugget stability-factors critical for maintaining dimensional accuracy and minimizing distortion in downstream manufacturing processes. These findings are especially relevant for high-speed automated assembly lines where process reliability and low defect rates are essential. This research provides practical insights and parameter guidelines for achieving high-quality, energy-efficient spot welds, contributing to improved production outcomes and reduced environmental impact.