Effects of Coating Weight on the Resistance Spot Weldability of Galvanized Steel

The influence of coating weight on the weldability lobe and electrode life performance of a zinc-coated steel was studied. Variations in substrate chemistry, coating weight and welding process were minimized. Statistically quantified weldability lobes were generated for each material. The size and shape of these lobes were found to be relatively invariant to coating weight over the range of coating weights studied. However, the degree of scatter in the data increased with coating weight. Surprisingly, decrease in coating weight did not result in longer electrode life. The intermediate coating weight G60* showed the longest electrode life. Even though material and process variables were substantially minimized, a significant level of scatter in the weldability data was measured. The irregular electrode wear during weld testing is thought to be a major source of this variability.