Galvanized sheet refers to a steel sheet with a layer of zinc plated on the surface. Galvanized sheet can be divided into ordinary spangle, fine spangle, flat spangle, no spangle and phosphating treatment according to the surface state. Galvanized sheet is divided into two types according to packaging: cut-to-length galvanized sheet and coiled galvanized sheet. Galvanized sheets are generally packaged with iron sheets, and the galvanized sheets should be bundled firmly to prevent mutual friction between the galvanized sheets. HUNGTHAI METAL has many years of production experience, providing customers with high-quality galvanized steel coils, color-coated steel coils.
The main reasons for the corrosion of galvanized sheet in use are mainly reflected in the following three aspects:
- During the entire service life of the galvanized sheet, the first corrosion that occurs is the oxidation of the surface galvanized layer, resulting in white rust. After a long time, the white rust on the surface further reacts with impurity gases such as carbon dioxide in the humid air to form black spots. When the galvanized sheet is used for a long time and the corrosion of the galvanized layer is serious, the steel base loses the sacrificial anti-corrosion effect of zinc, and begins to oxidize, resulting in red rust. Once the steel base begins to oxidize, the corrosion rate becomes rapid and the galvanized sheet ends its life.
- In addition, there are two special corrosion conditions of galvanized sheet called blackening. One is that after the galvanized sheet has been used for a period of time, due to the influence of elements such as lead in the galvanized layer, the dull part of the zinc flower will turn black, and the blackened galvanized layer still has a protective effect on the steel base. It just has a certain effect on lifespan.
- The corrosion resistance of galvanized sheet in dry environment or pollution-free environment is very good. However, in a polluted environment, the service life will be greatly shortened, and it must be pre-coated to form a color plate before use.