Effect of Spot Welding Parameters on Tensile Properties of DP 600 Steel Sheet Joints

In this study, the electric resistance spot welding process has been applied to dual-phase (DP 600 type) steel sheets. Spot welding parameters, namely, electrode form, electrode material, and electrode force were stayed constant, and welding current and welding time have been changed to detect the optimum welding parameters for maximum joint strength. The sample welded joints have been carried out as 1.0 mm-1.0mm, 1.2 mm-1.2mm, and 1.0 mm-1.2mm in three different thickness combinations in 4, 5, 6, 7, and 8 kA welding currents and 5, 10, 15, 20, and 25 cycles welding times. The strengths of the joints under uniaxial tensile-shear and tensile-peel loading have been studied and compared with the conventional spot welds of maximum joint strength for similar thickness steel sheets. The microstructure and hardness of spot welded joint samples have also been studied andrecommendations were given to users showing the optimum welding parameters.