The Galvanising Process
- Material Inspection
Check for material condition, welding and drilling, if necessary and if appropriately done
- Degreasing(Caustic Cleaning)
An alkaline solution removes dirt, oil, grease, shop oil, and soluble markings.
- Pickling
Diluted hydrochloric acid is used to remove surface rust and mill scale to provide a chemically clean metallic surface.
- Fluxing
Steel is immersed in liquid flux (zinc ammonium chloride solution) to remove oxides and to prevent oxidation prior to dipping into the molten zinc bath.
- Galvanising
The article is immersed in a bath of molten zinc at around 450°C. During galvanising, the zinc metallurgically bonds to the steel, creating a series of highly abrasion-resistant zinc-iron alloy layers, commonly topped by a layer of impact-resistant pure zinc.
- Finishing
After the steel is withdrawn from the galvanizing bath, excess zinc is removed by draining or vibrating. The galvanised item is then air-cooled or quenched in liquid and sent for inspection and testing.
Process diagram
