Effect of TiC coating on electrode tip surface on electrode degradation during micro-resistance spot welding

The effects of TiC coating on electrode tip surface on electrode degradation mechanism were studied during micro-resistance spot welding of nickel-plated steel to nickel sheet. The results indicate that the electrode degradation mechanism is basically caused by deformation at electrode tip and wear due to fracture of local welding between the electrode tip face and sheet happened at electrode surface during micro-resistance spot welding of nickel-plated steel to nickel sheet. The electrode tip life of CuCrZr electrode with TiC coating (1200 welds) doubles that of CuCrZr electrode (600 welds), because the TiC particles contained in the coating deposits can prevent local welding between the electrode surface and nickel-plated steel, then decrease the deformation of electrode surface.