Galvanized coil: dip the steel sheet into the molten zinc bath to make the surface adhere with a layer of zinc. It is mainly produced by continuous galvanizing process, that is, the rolled steel plate is continuously immersed in the molten zinc plating bath to make galvanized steel plate; Alloyed galvanized steel plate. This kind of steel plate is also made by hot-dip method, but it is heated to about 500 ℃ immediately after being out of the tank to form an alloy film of zinc and iron. This galvanized coil has good coating adhesion and weldability.