1. Material Preparation
The raw material of galvanized steel coils is ordinary steel coils, which are cut, ground, leveled and longitudinally sheared to obtain flat sheets of the required size. In these steps, it is undoubtedly crucial to ensure the dimensional accuracy of the steel coil and the smoothness of the sheared edges.
2.Surface treatment
Before galvanizing, steel coils need to undergo surface treatment. First, it is acid-washed with hydrochloric or sulfuric acid to remove surface rust and dirt. Then, it is thoroughly rinsed with water and dried with compressed air. This is done to ensure that the galvanized layer adheres closely to the steel surface, thus enhancing its corrosion resistance.
3. Hot-dip galvanizing
Hot-dip galvanizing is a key process in the production of galvanized steel coils. The processed steel coil is immersed in a galvanizing bath where molten zinc covers the surface to form a zinc alloy. The process is carried out at high temperatures, usually controlled between 450 and 500°C. In addition, the thickness of the zinc layer needs to be adjusted to achieve optimum corrosion resistance.
4. Cooling and passivation
After hot-dip galvanizing, steel coils are cooled and passivated. Cooling, which can be achieved by water or air cooling, is aimed at rapidly reducing the temperature of the coil to prevent any structural or performance effects on the zinc layer. Passivation, on the other hand, is aimed at improving the corrosion resistance of the zinc layer and is usually applied to the surface with a chromium-based passivator.
Galvanized coils are mainly used in the following industries.
A large number of thin galvanized coils are used in automotive manufacturing, refrigerated containers, construction, ventilation and heating facilities and furniture manufacturing. Galvanizing has become an important method of corrosion protection for iron and steel, not only because zinc forms a dense protective layer on the surface of the steel, but also because of its cathodic effect, which prevents corrosion of the ferrous base material through cathodic protection when the galvanized layer is broken.
Construction industry: roofs, roofing components, balcony rolls, tables, kiosks, warehouses, roller shutters, heaters, rainwater pipes and so on.
Household appliances: refrigerators, washing machines, switchgear, air conditioners, microwave ovens, toasters, photocopiers, vending machines, electric fans, vacuum cleaners and so on.
Furniture industry: lampshades, closets, bookshelves, counters, signboards, medical equipment and so on.
Transportation industry: auto ocean ceiling rolls, car shell compartment rolls, tractors, trams, containers, highway walls, ship bulkhead rolls, etc.
Other aspects: musical instrument shell dumpster, billboards, clocks and watches, photographic equipment, meters, etc. Color coated steel coil is hot-dip galvanized coil, hot-aluminum-zinc plated coil, electro-galvanized coil, etc. as the base coil, after the surface pre-treatment.
