Have you ever wondered how hot-dip galvanized steel coil is produced? Today, we’ll show you how it is produced and packaged.

The Basic Steps of Hot Dip Galvanizing Process can be concluded as follows:

The hot-dip galvanizing process consists of three basic steps:

#1 Surface preparation

#2 Galvanizing

#3 Product inspection

Below we will look into the detailed measures.

#1 Surface preparation

Fabricated steel coils are first unrolled and brought to the surface preparation line, where the steel is cleaned and processed for hot drip treatment. Surface preparation is a critical step in the production of galvanized steel as inadequate surface preparation can lead to premature failure of the metal. Surface preparation involves three steps:

1) Degreasing, where the steel coil is bathed into a hot alkali solution to remove any organic contaminants from its surface to promote strong zinc-iron bonding.

2) Pickling, where the alkali-treated steel coil is exposed to a bath of heated sulfuric acid to remove iron oxides from the steel surface.

3) Fluxing, where the steel coil is further treated to a zinc ammonium chloride solution, to remove any remaining traces of oxides and form a protective layer onto the steel surface to prevent the reforming of oxides.

#2 Galvanizing

Once the surface has been prepared, the steel coil is now ready for a splash in a molten zinc bath. This stage of the process is called galvanizing. Solid zinc is molten in a kettle at 815°F to 850°F. The cleaned steel coil is then immersed into the kettle, while the original temperature of the kettle is retained. The iron atoms in the steel metallurgically bond with zinc atoms to form an intermetallic zinc-iron alloy layer on the surface of the steel coil.

The coated steel coil is then slowly withdrawn from the kettle. Any excess zinc is removed by centrifuging, vibrating and/or draining. The final step of the galvanizing stage involves the cooling of the zinc-coated steel coil. This is done either by leaving the steel out in the open or immersing it in a passivation solution. Steel has now been transformed into galvanized steel.

#3 Product Inspection

To ensure that the hot-dip galvanized steel complies with international manufacturing and safety standards, the product is tested and scrutinized for coating thickness and surface condition. If everything is okay, galvanized steel is then packaged and loaded for shipment. And that’s how hot-dipped galvanized steel is produced.

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