For galvanized coils, the thin steel sheets are immersed in a molten zinc bath to adhere a layer of zinc sheet steel on the surface. It is mainly produced by continuous galvanizing process, that is, the rolled steel plate is continuously immersed in a plating tank with zinc melted to make galvanized steel plate; alloyed galvanized steel plate. This kind of steel plate is also manufactured by hot dip method, but immediately after being out of the tank, it is heated to about 500 ℃ to form an alloy coating of zinc and iron. This galvanized coil has good paint adhesion and weldability.
Galvanized Process
(1) normal 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 spangle-free coating
The coating obtained by adjusting the chemical composition of the plating solution has no visible spangle morphology and a uniform surface.
(4) zinc-iron alloy coating zinc-iron alloy coating
Heat treatment of the steel strip after passing through the galvanizing bath to form an alloy layer of zinc and iron throughout the coating. A coating that can be painted directly without further treatment other than cleaning.
(5) differential coating
For both sides of galvanized steel sheet, coatings with different zinc layer weights are required.
(6) Smooth skin pass
Skin-passing is a cold-rolling process performed on galvanized steel sheets with a small amount of deformation for one or more of the following purposes.
Improve the surface appearance of galvanized steel sheet or be suitable for decorative coating; make the finished product not see the phenomenon of slip line (Lydes line) or crease during processing to minimize temporarily, etc.
Post time: Jun-09-2022