At present, the most effective rust prevention method for iron fences is hot-dip galvanizing. A zinc iron alloy layer and a pure zinc layer are formed on the surface of the molten zinc liquid to prevent oxidation of the oxidized workpiece. The rust prevention period can reach 20-50 years, without maintenance, safe and reliable, making it a better rust prevention method for forged iron workpieces.

Hot dip galvanizing process

1. Inspection and treatment before pickling

Check whether the forged iron workpiece has factory machined holes (exhaust holes, night zinc, suspension holes), the degree of corrosion on the surface of the forged iron workpiece, whether the surface cover can be removed with hydrochloric acid (if there is paint), and whether grease should be burned, ground, alkali washed, etc.).

2. Degreasing (alkaline washing)

It is equipped with heating equipment to eliminate grease and paint on the surface of iron workpieces.

3. Washing

Remove alkaline water and deposits on the surface of forged iron workpieces.

4. Pickling

Remove other surface coverings, such as rust and scale

5. Check and handle after pickling:

Is  pickling effect ideal? For example, if pickling is insufficient and pickling is repeated, if  treatment before pickling is not thorough, it needs to be re treated before pickling.

6. Wash

Remove acidic water and other deposits from the surface of forged iron workpieces

7. Upper plating agent

Before galvanizing, clean the surface of workpiece again to ensure that the surface does not rust.

8. Drying

Raise temperature of forged iron workpiece to avoid excessive moisture on the surface of  forged iron and explosion during galvanizing.

9. Hot dip galvanizing

Immerse the workpiece in a molten zinc solution at 440 ° C-470 ° C for a certain period of time, and then obtain a layer of zinc iron alloy and pure zinc on the surface of the forged iron workpiece.

10. Passivation

Provide corrosion resistance to the surface of the workpiece, reducing or prolonging appearance of white rust.

11. Heat dissipation

Prevent the workpiece from cooling and retracting to prevent tissue rupture.

12. Organize

Remove gamma zinc and zinc dust adhering to the coating surface

13. Inspection

Inspect and measure the coating, visually inspect the workpiece.