Statistical modeling and optimization of the resistance welding process with simultaneous expulsion magnitude consideration for high-strength low alloy steel

In this investigation, the regression analysis together with the desirability function approach was involved to optimize the resistance welding parameters for the high-strength steel HSLA 420. The Box-Behnken experimental design (BBD) was employed for the control factors of welding time, welding current, and electrode pressure. The values of nugget diameter, ultimate peak load, maximum displacement, and absorption energy were identified and processed using the approach of multiple-objective optimization based on ratio analysis (MOORA). The weight loss of the base metal before and after welding was measured and computed to estimate the welding expulsion magnitude. The calculated statistical parameters displayed that the welding current had the most momentous influence on the welding quality and welding expulsion. The welding joints free of expulsion with sufficient mechanical properties can be achieved at the welding current of 8.4 kA, electrode pressure of 0.5 MPa, and welding time of 13 cycles.