Effect of Double-Pulse Resistance Spot Welding on the Mechanical Properties of High Strength Low Alloy S700 Steel

In this study, the impact of single-pulse and double-pulse resistance spot welding strategies on hot- rolled high-strength low alloy structural steel, specifically S700 with a thickness of 1.2 mm, has been examined regarding their influence on the mechanical strength and fracture characteristics of joints. Samples prepared using different welding currents were investigated for their tensileshear strengths, fracture energies, fracture modes, and geometric properties of the joints. It has been determined that when doublepulse resistance spot welding is used, expulsion occurs later during the joining process, allowing for larger nugget diameters to be achieved as a result. As a result, in double-pulse welding applications, the tensile-shear strength and fracture energy have been improved by 4.5% and 14.6%, respectively, compared to single-pulse welding. Additionally, in double-pulse welding applications, mechanical strengths have become more stable, and the standard deviations in measurements have decreased significantly.