Extending the life of aluminum spot welding electrodes through oxide layer disruption

Abstract The growing prevalence of aluminum sheets in future body-in-white concepts highlights the necessity for unceasing developments in joining techniques. This necessity arises from the distinctive characteristics of aluminum in comparison to conventional steel components. A significant challenge is the optimization of electrode lifespan in resistance spot welding, a process that is widely employed due to its reliability. The brief operational lifespan of electrodes during aluminum welding can be attributed to the insulating properties of the aluminum oxide layer that forms on the surface of the metal. One potential solution to this problem is to mechanically fracture the oxide layer prior to welding. The study investigates the influence of different relative movement configurations between electrodes and sheets on electrode wear and contact resistance during spot welding processes. Experimental setups with varying movement types—rolling frictionless, rolling with friction, translational, and stationary—were analyzed to determine their impact on sheet surface, surface shear stresses, and electrode wear. Confocal microscopy revealed noticeable surface changes depending on the movement configuration, with translational and rolling with friction movements exhibiting noticeable abrasive effects. Simulations supported experimental findings, highlighting variations in shear stress distribution and oxide layer disruption.