Electrode tip life improvement in resistance microwelding of nickel-plated steel thin sheets

The effect of the TiC composite coating on electrode degradation was analyzed during series-mode micro-resistance welding of very thin sheets of nickel-plated steel to sheets of nickel. In order to compare the effectiveness of the composite coating on dispersion strengthened versus precipitation strengthened electrode material, electrodes of both types were subjected to controlled welding trials in both coated and uncoated conditions. Scanning electron microscopy (SEM) examination revealed that the surface of the electrode tip was relatively smooth and clean even after a few hundred of welds. It was found that the TiC composite coating increased the tip lives of Cu-Cr-Zr and Cu-Al2O3 electrodes by 70%.