Galvanized coil, a thin steel plate is immersed in a molten zinc bath so that a layer of zinc adheres to the surface. At present, the continuous galvanizing process is mainly used for production, that is, the rolled steel plate is continuously immersed in a plating bath containing molten zinc to make galvanized steel plate; alloyed galvanized steel plate. This kind of steel plate is also made by the hot dip method, but it is heated to about 500°C immediately after coming out of the tank to form an alloy film of zinc and iron.