Comparative Study of the Mechanical Properties of Spot Welded Joints

This work presents a comparative study of the mechanical properties of resistance spot welded joints (RSW). RSW is widely used in sheet joining. Hence, the mechanical properties and their strength are presented. The main parameter is the welding current that has a big role on the heat generation and joint strength. The strength improvement due to the current increasing is regular and more effective than the weld time and the electrode pressure. Stainless steel has good weldability in sheet form. Galvanized steel, aluminum and carbon steel have been widely spot-welded. Moreover, dissimilar materials are also spot weldable where the two sheets of different metals can be joined. For the same sheet thickness at 1 mm, it was shown the shear strength of mild steel 3.8 KN, while for aluminum 1.4 KN this mean the shear strength of mild steel higher than aluminum. For the same metals, the increasing of the thickness will increase the strength. This is due to the weld area increasing. All the values were taken at the pull-out fracture condition. Hence, the suitable weld area at the welding condition was assumed. Fatigue strength for some metals has been presented. Fatigue strength of MS1300 is higher than those of steel DQSK, and steel DP800 at the for 1.6 mm thickness and stress ratio, R= 0.1. Because of the thickness, it has a minor effect on the fatigue properties of spot welded joints.