For galvanized coils, the thin steel plate is immersed in the molten zinc tank, so that a thin steel plate with a layer of zinc is adhered to the surface. It is mainly produced by continuous galvanizing process, that is, continuous immersion of rolled steel sheets in a galvanizing tank with molten zinc to make galvanized steel sheets; alloyed galvanized steel sheets. This kind of steel plate is also manufactured by hot dipping, but immediately after it is discharged from the tank, it is heated to about 500°C to form an alloy film of zinc and iron. This galvanized coil has good paint adhesion and weldability.