Galvanized steel coil, a thin steel sheet that is dipped in a bath of molten zinc to adhere a layer of zinc to its surface. It is mainly produced by continuous galvanizing process, that is, coils of steel plates are continuously dipped in a plating tank with molten zinc to make coils.
Type of substrate
Cold-rolled coil and hot-rolled pickled coil
Classification of surface treatment
1 passivation
The galvanized layer is passivated to reduce folding corrosion (white rust) under tidal temperature storage and transportation conditions. However, the anti-corrosion performance of this chemical treatment is limited and, moreover, hinders the adhesion of most paints. This kind of treatment is generally not used in the zinc-iron alloy coating. Except for the smooth surface, as a routine, the manufacturer conducts passivation treatment on other types of zinc coating.
2 oiled
Oiling can reduce steel plate corrosion under wet storage and transportation conditions, and re-oiling steel plates and steel strips after passivation treatment will further reduce corrosion under wet storage conditions. The oil layer should be able to be removed with a degreasing agent that does not damage the zinc layer.
3 paint seal
An additional corrosion protection, especially anti-fingerprint properties, can be provided by applying a very thin film of transparent organic coating. Improves lubricity when forming and acts as an adhesion primer for subsequent coats.
4 Phosphating
Through phosphating treatment, galvanized steel sheets of various coating types can be coated without further treatment except for normal cleaning. This treatment can improve the adhesion and anti-corrosion performance of the coating, and reduce the risk of corrosion during storage and transportation. After phosphating, it can be used with a suitable lubricant to improve the forming performance.