Types of galvanized steel sheet: how are oil, passivation, sealing and phosphating combined?
Galvanized steel sheet is used to prevent corrosion on the surface of the steel plate and extend its service life. The surface of the steel plate is coated with a layer of metallic zinc. This type of galvanized steel sheet is called galvanized sheet. Galvanizing is a cost-effective and effective method of corrosion protection, with approximately half of the world's zinc production used in this process.
Divided into 2 main types according to production methods
1.Electro-zinc plated sheet: A galvanized sheet produced by having zinc ions pass electrons through an electrolyte containing zinc ions to generate electrons to form zinc deposited on the surface of the strip.
2.Hot-dipped galvanized sheet: A galvanized sheet produced by galvanizing a cold-rolled or hot-rolled strip of steel in a bath of molten zinc in a continuous hot-dip galvanizing line.
Thermal zinc coated steel sheet can be divided into:
1.Hot dip pure zinc plate: The zinc content in the molten zinc solution is more than 99%.
2.Hot dip galvanized iron alloy plate: The zinc content in the molten zinc solution is more than 99%. Thereafter, a zinc-iron alloy layer is formed on the entire coating layer by alloy treatment process, and the iron content in the alloy coating layer is usually 7-15%.
3.Aluminum-zinc hot plate: The aluminum content in the molten zinc solution is about 55%, the silicon content is about 1.6%, and the rest is zinc.
According to surface treatment
The surface treatment of galvanized sheets is also sequential. It is not a random combination process. Different surface treatment processes have different uses. The following are some common combinations of surface treatment processes and their uses:
For example: The substrate is electrozinc plated plate
| motherboard | Layer 1 | Layer 2 | Layer 3 | Principal function |
|---|---|---|---|---|
| Electrical Galvanized Steel Sheet | oil | Form a protective layer on the surface of steel sheet, reduce corrosion and scratches | ||
| Phosphating | Form a dense thin phosphating film on the surface of steel to reduce corrosion. | |||
| Phosphating | oil | Reduce white rust and improve molding performance | ||
| Phosphating | Chrome-free closure | Lubrication and improve its anticorrosive ability, reduce white rust, ready for painting. | ||
| Phosphating | Chrome-free closure | oil | Reduce white rust and improve molding performance | |
| Chromium-free passivation | Application of an organic solution without hexavalent chromium to produce a passivation film | |||
| Chromium-free passivation | oil | Reduce white rust on steel surface | ||
| No chrome no fingerprint | No fingerprint would show on the steel surface with the special protection layer | |||
| Chrome-free self-lubricating | Can improve the lubrication of steel surface |