Welding Zinc Coated Sheet Metal

When galvanized steel is arc welded the heat of the welding arc vaporizes the zinc coating in the weld area.

Welding zinc coated sheet metal.

The heat of the arc will burn off the zinc coating without problems. Zinc is the coating used on galvanized metals and when you heat the metal it produces vaporized metal droplets which are called fumes. Welding galvanized steel is a dangerous task since the galvanized zinc coating on the metal becomes extremely toxic when it s heated. Do you weld on galvanized metals.

Unless there is a thick zinc coating flux core welding is the same process as welding non galvanized steel you select your volts and the amp output of your welder according to the thickness of the metal you re welding. Take the proper safety precautions by wearing a welding mask a good welding respirator gloves and an apron. Coated steels mainly having zinc coatings are readily welded provided that the important factors are understood and the process is set up appropriately. The challenge is welding over the zinc coating.

When any fusion welding methods are used the heat input must be as minimal as possible in order to limit the heated zone in the metal coated sheet. Welding of zinc coated steel can be done but specific precautions should be taken. However the resulting weld may present many issues such as excessive porosity unacceptable bead appearance lack of fusion cracks and excessive spatter. Similar to scratched areas of the coating also in the narrow weld the sacrificial effect of the zinc based coating provides cathodic corrosion protection.

The zinc volatilizes and leaves the base metal adjacent to the weld. This is because the boiling point of zinc is below the melting point of steel. One of the most significant health hazards in the welding process is the generation of fumes and gasses.