HUNGTHAI METAL has many years of experience in producing steel coils and is a professional manufacturer dedicated to providing customers with professional steel solutions.
This article will introduce the classification of galvanized sheets and the commonly used post-treatment processes:
- Classification by manufacturing and processing
(1) Electro-galvanized sheet: The electro-galvanized sheet is produced by electrifying the steel sheet through an electrolyte with zinc ions, so that the zinc ions obtain electrons, which are converted into zinc and deposited on the surface of the steel sheet.
(2) Hot-dip galvanized sheet: A galvanized sheet produced by hot-dip galvanizing by infiltrating cold-rolled or hot-rolled steel strips into molten zinc liquid in a continuous hot-dip galvanizing production line.
- Classification by coating form
1) Hot-dip pure cold-rolled steel sheet: The zinc content in the molten zinc solution exceeds 99%.
2) Hot-dip galvanized iron alloy sheet: The zinc content in the molten zinc solution exceeds 99%. A zinc-iron alloy layer is produced on the coating through an alloy strengthening treatment process, and the iron content in the alloy coating is generally between 7 and 15%.
3) Hot-dip galvanized sheet: the content of aluminum in the molten zinc solution is about 55%, the content of silicon is about 1.6%, and the other components are zinc.
- According to the form of post-treatment, according to the form of post-treatment, the galvanized sheet is divided into passivation, oiling, passivation oiling, paint sealing, phosphating or no treatment.
(1) Passivated galvanized sheet. Passivation galvanized sheet is to reduce white rust under humid conditions, and a passivation protective film is further applied on the surface of the product after galvanizing. According to the type of passivation film, it is divided into hexavalent chromium passivation, trivalent chromium passivation, chromium-free passivation and other products, which are generally not used for zinc-iron alloy plates.
(2) Oil coated galvanized sheet. The purpose of oiling is also to prevent the product from getting wet and causing white rust. But since anti-rust oil is extremely volatile or wiped off, it only works before it is used. Oiling methods include electrostatic oiling and roller oiling. If you want to prevent the product from producing white rust during its use period, it is best to use passivation and oiling. The color-coated substrate is more suitable for light oiling treatment, and the applied oil can be cleaned and removed in the pre-treatment of the color-coated line.
(3) Paint-sealed galvanized sheet. Paint seals are commonly known as fingerprint-resistant products. In order to prevent galvanized products from leaving fingerprints during processing, a very thin anti-fingerprint protective film is applied to the surface of galvanized products, which can also improve the corrosion resistance and performance of products. The coating properties of the product. Suitable for special needs of home appliances.
(4) Phosphating galvanized sheet. Due to the poor bonding force between the galvanized sheet and the organic coating, the coating requirements cannot be met. The phosphating treatment of the galvanized sheet before coating can effectively improve its corrosion resistance and enhance its bonding force with the organic coating. .
- Post-treatment process combination and application
The surface treatment of galvanized sheet is also in order, and different surface treatment processes have different uses.