Our Galvanization Process, step-by-step
The HOT-DIPPED GALVANIZED finish is a classic steel finish, it's been used for over 100 years to protect steel parts and products in extreme environments. It is one of the most long-lasting and toughest corrosion control coatings for steel, and can last up to 70 years in most environments. The finish is virtually abrasion-proof and has an attractive crystalline lattice that starts off bright and shiny, but soon acquires a matte grey patina.
1. Alkalai Bath
The steel surface must be perfectly clean in order for the zinc to adhere to the metal. Here the rack is being dipped into a hot alkali solution to remove any organic contaminants, grease or oils.
2. First Rinse
The rack is then dipped in a rinse to remove any alkali solution that may remain. You can see that this process does not remove oxidation, there's still a bit of rust on these racks that would interfere with the coating.
3. Pickling Bath
To remove the rust, a diluted solution of heated acid removes mill scale and iron oxides (rust) from the steel surface, preparing the surface for the flux.
4. Second Rinse
The rack is then dipped into a rinse to remove any of the previous bath's acidic solution that could contaminate the flux solution. You can see here that all of the rust is gone and the surface is prepped for the first zinc solution.
A zinc ammonium chloride solution removes any remaining oxides and deposits a protective layer on the steel to prevent any further oxides from forming on the surface prior to immersion in the molten zinc.
The bike rack immersed in molten zinc and allowed to dry in ambient air, where it grows its own unique crystalline pattern. The rack is then hand-filed to remove any galvanizing flash and tested for thickness. The coating is then ready for shipping to the site.