The study aims to investigate the influence of welding parameters on nugget formation, shear strength and residual stress distribution in double- and triple-layer resistance spot welding (RSW) joints, and their effects on sidewall weld deformation. It seeks to reveal the significant impact of triple-layer RSW joints on deformation patterns and maximum deformation, providing theoretical guidance for accurately simulating and controlling weld deformation in sidewall structures with multi-layer, unequal-thickness RSW joints.
This study conducted RSW experiments and established a finite element model of the thermal-electro-mechanical multi-physics field to analyze the residual stress distribution in double-layer and triple-layer RSW joints. Using the constitutive strain method, the influence of the RSW joint was incorporated into the side wall structure to evaluate its impact on welding deformation and residual stress. The research results demonstrated the significant influence of the joint configuration on the integrity of the side wall structure, providing a reliable framework for predicting and reducing welding deformation in multi-layer RSW components.
Increasing the welding current significantly enlarges the size of the weld nugget. The shear strength initially increases and then slightly decreases. Excessive current reduces the thickness of the weld nugget. The increase in electrode pressure inhibits the growth of the weld nugget thickness. The radius of the weld nugget and the shear strength initially increase and then decrease. The retention time prolonging causes the thickness of the weld nugget to increase first and then decrease, while the radius continues to increase. The shear strength initially increases and then decreases. The influence of the weld nugget thickness on the shear strength is greater than that of the radius. There are significant differences in the residual stress distribution between double-layer and triple-layer plate spot welding. The triple-layer plate forms a raised plastic strain ring due to the compression of the middle layer, and the residual stress is concentrated in the heat affected zone. The deformation of the joint side wall in triple-layer spot welding cannot be ignored. Changing the deformation mode and affecting the maximum deformation amount can provide a reference for accurately simulating and controlling the welding deformation of the side wall.
This study reveals the influence patterns of process parameters on the weld nugget size and shear properties of double-layer and three-layer uneven-thickness SUS301L stainless steel RSW joints, proving that the thickness of the weld nugget has a greater impact on the shear strength than the radius of the weld nugget, providing a reference for actual production. The differences in residual stress distribution of different plate layer structures were analyzed. After introducing the three-layer RSW joint, the welding deformation mode of the side wall changed, and the maximum deformation was affected, verifying the importance of the three-layer joint in deformation calculation, and providing a theoretical basis for accurately simulating the welding deformation of multi-layer uneven-thickness RSW joints and effectively controlling the side wall deformation.
