Hot-Dipped Galvalume Steel Coils
The galvalume & aluzinc steel sheet in coil uses the cold-rolled steel sheet as a substrate and solidified by 55% aluminum, 43.4% zinc and 1.6% silicon at 600 °C. It combines the physical protection and high durability of aluminum and the electrochemical protection of zinc. It is also called aluzinc steel coil.
The surface of galvalume steel sheetfeatures a unique star-shape, smooth and plain, with silver color as primary colour. Its special plating structure could be well corrosive -proof.
Advantage of Galvalume Steel Coils
Strong corrosion resistance, 3 times that of galvanized steel sheet.
The density of 55% aluminum is smaller than the density of zinc. When the weight is the same and the thickness of the plating layer is the same, the area of the galvalume steel sheet is 3% or larger than that of the galvanized steel sheet.
The difference between galvanized and galvalume
The primary difference lies at its coating layer. For the galvanized sheet, a layer of zinc material is averagely distributed on the surface of galvanized sheet, playing as a positive sheet protective to the base metal, in another word, zinc works as substitute for corrosive-proof protecting the base metal until it is torn off.
While the galvalume sheet’s surface is a coating layer consisting of 55% aluminium, 43.5% zinc and other few elements, which appears a honeycomb structure under microscopic observation. Aluminium honeycomb wraps the zinc.Under such circustances, even though the coating of galvalume also plays its protective role as positive sheet, however, such protection decrease sharply due to declining content of zinc and no easily electrolysis when zinc wrapped by aluminium.
Therefore, once the galvalume sheet is cut open, the verge of cut would be generally losing its protector and quickly go rusting. So we should cut as less as possible, once cutting happen, use anti-rusting paint or zinc-rich paint for protecting the verge, extending its lifespan.