Experimental study of the shunting effect on tensile-shear strength of resistance spot welds in AA2219 sheets

The shunting effect in resistance spot welding (RSW) occurs due to the side electrical current created through the previous spot welds. In creation of alternating welding points, the quality of subsequent welding points is affected by a side electric current due to electro-thermal changes. This shows that the analysis of the effect of the side current is important for achieving cognition of how different parameters affect this process. Therefore, the dimensions of the welding nuggets, the metallurgical structures and the mechanical strength of the welding points are affected by the changes in the electric current and the temperature distribution caused by this current. The amount of this current depends mostly on factors such as distance, number and size of previous spot welds. In this study, experimental research was performed to investigate the shunting effect on the tensile-shear strength of RSW spot welds in aluminum alloy 2219 sheets. The most important factor in shunting (welding distance) together with welding current and time was investigated by three design of experiment factor (DOE) within the welding range to achieve a statistical model based on tensile-shear strength results. An experimental regression model was derived. Results show that increasing the welding current or distance increases the tensile-shear strength of the joints.