Experiments and Simulations Study on Resistance Spot Welding of HSLA Steel Sheets: Process Parameters and Quality Analysis

Abstract

This paper presents the experimental and simulation works done to elucidate the effect of Resistance Spot Welding (RSW) process parameters on weld quality of high-strength low-alloy (HSLA) 340 steel sheets. Experiments were conducted to measure the nugget size, hardness, and joint failure type and energy. Further, the coupled electrical-thermal-mechanical simulations were made, and the predicted current density, temperature distribution, nugget size, thermal cycles and stress distribution were analyzed, and found that the predicted nugget sizes in good agreement with the measured data. Hardness variation across the weld zones with process parameters found to be less significant because of rapid heating and cooling rates, and it was confirmed by the formation of fully martensite. Tensile-shear test and fractography results confirmed interfacial (brittle) failure for the nugget diameter, d<4t, else pull-out (ductile) failure. Henceforth, the authors strongly recommend to use the coupled phenomena model and design the optimal weld schedule to yield a pull-out failure of the RSWed lap joints with low residual stresses in a cost-effective manner in contrast to the tedious experimental route. © ASM International 2025.