Optimization of Process Parameters for Resistance Spot Welding of 17-4PH Stainless Steel Using Response Surface Methodology

This study explores the resistance spot welding (RSW, resistance spot welding) characteristics of precipitation-hardened stainless steel 17-4PH with dissimilar thicknesses (0.3 mm and 0.66 mm) to optimize welding conditions. Widely used in aerospace applications for its high-temperature strength and corrosion resistance, 17-4PH requires precise welding methods to ensure consistent quality. A Central Composite Design (CCD, central composite design) was utilized to optimize process parameters, focusing on weld current (4-6 kA) and weld time (200-300 ms). The weldability was assessed through tensile shear strength, nugget size, and the occurrence of expulsion. Regression analysis produced models with coefficients of determination (R<sup>2</sup>) of 0.99 for both tensile strength and nugget size. ANOVA(analysis of variance) indicated weld current as the most significant factor, contributing 86.9% to tensile strength and 89.4% to nugget size. The optimal welding condition of 5.25 kA and 300 ms was verified experimentally, yielding prediction errors of 1.6% for tensile strength and 3.9% for nugget size. This research provides a robust framework for enhancing RSW processes for 17-4PH with dissimilar thicknesses, supporting its wider application in high-performance industries like aerospace.