Industry News

The process of hot dip galvanizing actually is a metallurgical bond between zinc and steel with a series of different iron-zinc alloys. It is always used for metal basket, steel racks and so on. lThe final coated steel can be used in the same way as uncoated. And a typical hot-dip galvanizing line operates as follows:

1. Steel is cleaned using a caustic solution. This process can removes oil, grease, dirt, and paint.

2. The caustic cleaning solution is rinsed off.

3. The steel is pickled in an acidic solution to remove mill scale.

4. The pickling solution is rinsed off.

5. Zinc ammonium chloride as a flux is applied to the steel to inhibit oxidation of the cleaned surface upon exposure to air. The flux is allowed to dry on the steel and aids in the process of the liquid zinc wetting and adhering to the steel.

6. The steel is dipped into the molten zinc bath and held there until the temperature of the steel equilibrates with that of the bath.

7. The steel is cooled in a quench tank to reduce its temperature and inhibit undesirable reactions of the newly formed coating with the atmosphere.

Steel strip can be hot dip galvanized in a continuous line. Hot dip galvanized steel strip is extensively used for applications requiring the strength of steel associated with the resistance to corrosion of zinc. One common use is in metal pails. Galvanized steel is also used in most heating and cooling duct systems in buildings

A Hot Dip Galvanized coating is relatively easier and cheaper than an organic paint coating of equivalent corrosion protection performance. The international standard for Hot Dip Galvanizing is BS EN ISO 1461, which specifies a minimum coating thickness to be applied to steel in relation to the steels section thickness.