Galvalume steel is carbon steel coated with an aluminum-zinc alloy using a continuous hot-dip process, combining the corrosion protection and high-temperature resistance of aluminum with the formability and galvanic protection of zinc.
The galvalume coating is an alloy consisting of approximately 55% aluminum, 43.4% zinc and 1.5% silicon by weight, which is applied to steel by the continuous hot dip process. Galvalume steel sheet offers the best qualities of aluminum coated (aluminized) and zinc coated steel sheet (galvanized). The aluminum/zinc coating has barrier corrosion resistance and heat resistance similar to aluminum coated steel. It also has good bare edge galvanic protection and forming qualities similar to continuously annealed commercial quality galvanized. The appearance of Galvalume coating is quite distinctive. Its smooth, flat and fine spangle and a silvery metallic appearance make it attractive in unpainted applications.