An Investigation into the Measurement and Evaluation of Volumetric Voids in Advanced High Strength Steel Resistance Spot Welds

This study delves into the mechanism of void formation in advanced high strength steel (AHSS) resistance spot welds, which have vital applications in modern automotive manufacturing. Voids, particularly shrinkage cavities, pose significant challenges in maintaining weld integrity. Existing theories propose that these voids result from factors like material expulsion and welding conditions, but the precise mechanisms remain unclear. This study employs various AHSS grades, sheet thicknesses, and welding parameters to examine void formation. Results reveal distinct void types (Types I, II, and III) influenced by sheet strength, thickness, and welding conditions. The roundness of voids varies with thickness and material strength, impacting the volume of voids. Furthermore, the study also employs high-speed imaging to understand the role of atmospheric gas entrapment during welding in void formation.