The Hot Dip Galvanizing Process
Hot Dip Galvanizing is a process where clean steel is immersed in molten zinc to provide a metalurgically bonded coating of zinc and zinc iron alloy on the surface of the steel.
An ITP (Inspection Test Procedure) is incorporated at each stage of the galvanizing process including stores and dispatch. This procedure will ensure any problems are rectified before continuing on through the process.
Steel is cleaned prior to the galvanizing stage by immersion in heated sodium hydroxide and solvents (caustic) to remove grease and paint after which it is rinsed in water.
The steel is immersed in hydrochloric acid to remove rust and mill scale and again the steel is rinsed prior to immersion in a flux solution. The purposed of the flux is to save the steel from re-oxidizing prior to galvanizing. The flux also breaks down zinc oxide floating on the surface of the molten zinc as the product enters the zinc.
The steel is dried prior to immersion in molten zinc. The steel product is agitated within the zinc to release ash and air, then the ash and oxides are cleared away before the product is withdrawn from the zinc bath. Zinc drips are cleared away while the zinc is still in a molten state and the product is then moved to a passivation and cooling bath.
This process provides protection from early re-oxidisation, ensuring that the coating will be stable during its early life, prior to a natural zinc patina formation which will continue to develop for some years, taking the galvanizing appearance from bright silver in colour to a dull grey over time.
Our team personally undertakes a quality check of each item. Galvanized items can then be stored at Albury Galvanizing until they are required on the client’s worksite.
Albury Galvanizing will also work with clients to provide the appropriate packaging for transport. This includes developing bespoke packaging solutions for high specification projects.