Galvanized process flow of cast iron pipe fittings

Galvanized process flow of cast iron pipe fittings

1. Pretreatment rust removal: Use mechanical or chemical methods to remove rust, oxides and impurities on the surface of pipe fittings. Pickling: Immerse the pipe into the acid solution to further remove surface oxides and impurities. Water washing: Rinse pipe fittings with clean water to remove acid residue.

2. Flux cleaning Use organic solvents (such as trichloroethylene) to clean pipe fittings to remove oil and water.

3. Auxiliary plating The pipe fittings are immersed in the auxiliary plating solution to form a film and promote the adhesion of the zinc solution.

4. Galvanized the pipe is immersed in molten zinc solution to form a layer of zinc coating on the surface of the pipe. Galvanizing time and temperature are determined according to pipe size and desired coating thickness.

5. Cooling The galvanized pipe fittings are removed from the zinc liquid and cooled naturally in the air.

6. Post-treatment passivation: the pipe fittings are immersed in the passivation solution to form a protective film to prevent zinc coating oxidation. Water washing: Rinse the pipe fittings with clean water to remove the passivation liquid residue. Drying: Put the pipe in the oven to dry and remove water.

Precautions The surface of the pipe fittings must be thoroughly cleaned before galvanizing, otherwise the adhesion of the zinc coating will be affected. Galvanizing temperature and time must be strictly controlled to ensure the formation of a uniform, dense coating. After galvanizing, passivation should be timely to prevent oxidation of zinc coating. The waste water and waste gas generated during the galvanizing process should be properly treated to avoid environmental pollution.