Production process of hot-dip galvanized steel pipe
Production process of hot-dip galvanized steel pipe
Hot dip galvanized steel pipe, also known as hot dip galvanized pipe, is a kind of steel pipe that is galvanized to improve its service performance. Based on the principle of combination and wide application, it is determined that the alloy layer is produced by the reaction of the substrate, thus combining the substrate with the coating. How are hot-dip galvanized steel pipes processed? The process flow of hot-dip galvanized steel pipe is divided into the following steps:
1. Alkali washing: some steel pipes have oil stains on the surface, so alkali washing is required.
2. Pickling: hydrochloric acid is selected for pickling to remove the oxide skin on the steel pipe surface.
3. Rinsing: mainly to remove the residual acid and iron salt attached to the steel pipe surface.
4. Dipping aids: the role of flux is to remove all impurities from the steel pipe surface, ensure clean contact between the steel pipe and the zinc solution, and form a good coating.
5. Drying: mainly to prevent the steel pipe from being immersed in the zinc pot and blasting.
6. Hot dip galvanizing: the temperature of zinc liquid in the zinc pot shall be strictly controlled at 450+5 ° C, the steel pipe shall be put into the galvanizing furnace and rolled into the three zinc dipping spirals in the galvanizing machine. The three spirals have different phases, making the steel pipe inclined on the spirals. With the rotation of the spirals, the steel pipe moves downward at one side to form an angle of inclination, and then enters the zinc bath, continues to move downward, and automatically falls on the slide rail in the zinc pot; When the steel pipe is lifted to the magnetic mixing surface, it will be attracted and moved to the pulling wheel track.
7. External blowing: the steel pipe passes through the external blowing ring to compress the air and blow away the excess zinc liquid from the steel pipe to obtain a smooth and clean appearance.
8. Pulling out: The amount of zinc can be controlled and the zinc consumption can be reduced by appropriately reducing the pulling-out speed.
9. Internal blowing: remove the excess zinc liquid on the inner surface of the steel pipe to obtain a smooth and clean inner surface. The removed zinc liquid forms zinc powder for recycling.
10. Water cooling: the temperature of the water cooling tank shall be controlled at 80 ℃, and the galvanized pipe shall be cooled.
11. Passivation: the passivation solution is sprayed on the finished pipe of the blow ring to make the pipe surface passivated. After the external blow ring, the excess passivation solution is blown off with compressed air.
12. Inspection: the galvanized steel pipe falls on the inspection bench, after inspection, the missing galvanized pipe is put into the waste basket, and the finished pipe is packed and put into storage.
