The resistance spot weldability of zinc coated steel was investigated during the early stages of electrode life experiments. Three different zinc coated steels were welded: galvanized, galvannealed, and electrogalvanized. The results of the weldability tests were evaluated and compared using welding current ranges and electrode carbon imprints. The tests were also performed with oiled and cleaned surfaces to better understand the influence of oiling on the shift in welding range curves and the resulting changes in electrode wear properties. Electrodes from selected tests were examined with electron probe microanalysis and light optical microscopy to compare the phases which formed on the electrode surface from different zinc coatings. It was determined that the change in the electrode contact area from electrode wear processes was the main reason for a shift in the welding current ranges. To better explain the results, the electrical contact resistance was measured at the electrode sheet interface during welding experiments on single sheets and the values were compared and discussed as a function of zinc coating and stage of electrode wear.
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