Research Information System
Hittite Journal of Science and Engineering, vol.12, no.1, pp.51-58, 2025 (Peer-Reviewed Journal)
Resistance spot welding (RSW) is widely utilized in the automotive industry due to its high efficiency, flexibility, and compatibility with automation. These advantages make it a preferred method for joining advanced high-strength steels, enabling lightweight designs without compromising structural integrity. This study explores the mechanical properties of resistance spot-welded joints between ultra-high-strength MS1500 steel and hot-rolled DD11 steel, with a focus on single-pulse and double-pulse welding strategies. The effects of varying current levels were evaluated in terms of tensile-shear strength, failure energy, nugget diameter, hardness distribution, and microstructural transformations. In single-pulse welding, expulsion was observed at a current of 8.6 kA, limiting joint performance. Conversely, the double-pulse welding strategy provided enhanced control, yielding superior results. Optimal performance was achieved at a second welding current of 8.4 kA, with a tensile-shear strength increase of 11.6% and a fracture energy enhancement of 32.2% compared to single-pulse welding. Beyond 8.6 kA, expulsion caused inconsistencies in mechanical properties, highlighting the importance of current optimization in welding strategies. The findings demonstrate the effectiveness of the double-pulse welding strategy in improving the strength and quality of resistance spot-welded joints.