The galvanized strip is cold-rolled or hot-rolled, and the long and narrow strips of steel are plated with different layers of materials called (zinc, aluminum). Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life. The hot-dip galvanized strip substrate undergoes complex physical and chemical reactions with the molten bath to form a corrosion-resistant, compact zinc-iron alloy layer Galvanized Steel Coil Manufacturer. The alloy layer is integrated with the pure zinc layer and the strip substrate. Therefore, its corrosion resistance is strong.
Production process of galvanized coil steel:
The first stage:
The whole roll of strip is pickled and decontaminated to achieve a bright and clean surface.
1 Direct galvanizing: After pickling, it is sent to a continuous annealing furnace and then enters a galvanizing bath for galvanizing.
2 Hot-dip galvanizing: After pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, sent to a continuous annealing furnace, and then introduced into a galvanizing bath for galvanizing.
3 Hot dip zinc: After pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride. Then, it is sent to a hot dip plating bath for galvanizing.
The third phase:
After the strip is galvanized, the tray is put into storage. The galvanized layer can be generally not less than 50g/m2 according to customer requirements, and any sample should not be less than 48g/m2.
Post-treatment of galvanized coil steel:
Post-treatment of galvanized strip steel includes three aspects, passivation, pre-phosphorization and oiling. Firstly, passivation treatment of the galvanized steel strip can improve the surface structure and gloss of the galvanized layer, improve the corrosion resistance and service life of the galvanized layer, and improve the bonding force between the coating and the base metal. Passivation treatment mainly uses chromate passivation. Adding an activator such as fluoride, phosphoric acid or sulfuric acid to the passivation solution results in a thicker chromate film after passivation. When there is fluoride in the passivation solution, the surface tension of the steel strip can be lowered, the film formation reaction can be accelerated, and the chemical polishing effect can be increased to make the passivation film fine and bright.
The application of galvanized strip steel meets modern needs and is now widely used as a building material. The galvanized strip steel has many years of no rust and corrosion resistance. It can be protected from the adverse environment and maintain its performance and appearance. In the process of using galvanized steel strip, in order to improve its working efficiency and its own characteristics, the galvanized strip steel finished product can be post-treated to make its performance better.