Characteristics of shunting in resistance spot welding for dissimilar unequal-thickness aluminum alloys under large thickness ratio

Highlights: • Shunting characteristics of unequal-thickness aluminum alloys 2219/5A06 resistance spot welding were investigated. • A finite element method was used to analyze the shunting effect. • Increasing the welding current is the preferred method to overcome the shunting effect than weld spacing. • Shunting effect of multiple spots welds depends on the interaction of weld spacing and temperature of specimen. This paper reports the shunting characteristics of dissimilar aluminum alloys 2219/5A06 of unequal-thickness for the resistance spot welding (RSW) process. Shunting experiments of two and multiple spot welds with different weld spacing were conducted. Numerical simulations were carried out to analyze the shunting effect by using the finite element code ANSYS. The results show that increasing the weld spacing is not an effective method to alleviate the shunting effect during RSW in dissimilar aluminum alloys with large thickness ratios because of the low bulk resistance of the aluminum alloy. Therefore, increasing the welding current is the preferred method to overcome the shunting effect. The shunting effect in multiple spot welds is influenced by a combination of effects due to both weld spacing and specimen temperature when other welding conditions are maintained constant.