A Comparison of the Resistance Spot Weldability of Hot-Dip and Electrogalvanized Sheet Steels

The majority of exposed and semi-exposed light gauge automotive components are being rapidly converted to metallic zinc coated steels. Since resistance spot welding is the dominant method of joining these parts, the weldability of a. variety of coated products was evaluated to facilitate direct comparison between hot-dip and electrogalvanized steels. The results indicate that the electrode life of electrogalvanized zinc and zinc-iron and hot-dip galvanized A40 materials are far superior to that of hot-dip galvanized zinc products. Some difference in current level for producing acceptable welds was observed between hot-dip and electro products. However, the substitution of electrogalvanized for hot-dip galvanized products of the same coating type will probably require only minor, if any, changes in current level in production situations. Further work is required to fully explain the differences in weldability noted between hot-dip and electrogalvanized materials.