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 adheres to the surface. It is mainly produced by continuous galvanizing process, that is, the coiled steel sheet is continuously immersed in a galvanized bath with molten zinc to make galvanized steel sheet; alloyed galvanized steel sheet. This kind of steel plate is also manufactured by hot dipping method, but immediately after leaving 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.