Welding Zinc Coated Sheet Metal

Three major problems with welding zinc coated steels are high spatter amount poor bead appearance and high internal porosities.

Welding zinc coated sheet metal.

This is because the boiling point of zinc is below the melting point of steel. The zinc volatilizes and leaves the base metal adjacent to the weld. Do you weld on galvanized metals. A reaction takes place between the zinc and steel surface to produce a chemically bonded alloyed coating.

Similar to scratched areas of the coating also in the narrow weld the sacrificial effect of the zinc based coating provides cathodic corrosion protection. Steel in the form of strip plate girders beams piping or fabricated articles is cleaned by means of an acid pickle or by shotblasting and then dipped in molten zinc. One of the most significant health hazards in the welding process is the generation of fumes and gasses. In addition the residuals left after welding on the surface of the plate can affect the corrosion resistance by interfering with the coating process.

This results from the variation in boiling points between zinc lower and steel. This is the smoky haze which consists of fine particles of metals or silicates. Welding of zinc coated steel can be done but specific precautions should be taken. Zinc is the coating used on galvanized metals and when you heat the metal it produces vaporized metal droplets which are called fumes.

When welding zinc coated steel you need to be extra careful to avoid inhaling the fumes.