The Hot Dip Galvanizing (HDG) process is a proven method used to protect steel from corrosion by coating it with a layer of molten zinc. Here’s a clear step-by-step procedure:
🔧 Procedure of Hot Dip Galvanizing
Steel is inspected for defects and cleaned to remove dirt, oil, grease, and paint.
2. Degreasing (Cleaning)
The material is dipped in an alkaline or acidic solution to remove organic contaminants.
3. Pickling (Acid Cleaning)
Steel is immersed in dilute hydrochloric or sulfuric acid to remove rust and mill scale.
4. Rinsing
Clean water is used to remove acid residues before the next step.
5. Fluxing
Steel is dipped in a flux solution (usually zinc ammonium chloride) to prevent oxidation before galvanizing.
6. Drying
The material is dried to ensure proper bonding with molten zinc.
7. Hot Dip Galvanizing
Steel is submerged in molten zinc at around 450°C, forming a strong metallurgical bond.
8. Cooling (Quenching)
The galvanized steel is cooled in water or air to solidify the coating.
9. Inspection & Finishing
Final inspection ensures coating thickness, uniformity, and quality.
