For galvanized coil, the steel plate is immersed in a molten zinc bath to allow a layer of zinc to adhere to the surface of the steel plate. It is mainly produced by continuous galvanizing process. The coiled steel plate is continuously dipped in a plating tank with zinc melted to make a galvanized steel plate. This kind of steel plate is also made by a hot-dip method. After it is out of the tank, it is heated to 500 ℃ to make it form an alloy film of zinc and iron. This galvanized coil has good paint adhesion and weldability.
The surfaces of galvanized coils are of the following types:

(1) regular spangle coating

During the normal solidification process of the zinc layer, the zinc grains grow freely and form a coating with an obvious spangle shape.

(2) minimized spangle coating

During the solidification process of the zinc layer, the zinc grains are artificially restricted to form the smallest possible spangle coating.

(3)spangle-free coating

The coating obtained by adjusting the chemical composition of the plating solution has no visible spangle morphology and a uniform surface.