Effect of holding time on microstructure and mechanical properties of resistance spot welds between low carbon steel and advanced high strength steel

The unequal thickness and dissimilar spot weld joint is simplified as shown in the figure. The interface suffers a shear stress, while the half circles of the cylindrical regions A/D and B/C suffer compressive and tensile stress under the tensile shear load, respectively. The test result demonstrates that the peak load and failure mode depend on the resistance force generated via the failure zone. For a given fusion size, the increase of holding time raises the hardness of fusion zone, and affects the peak load and failure mode of weld joints via enhancing the interfacial resistance capability.77