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Hot dip galvanising is one of the most widely used method to protect steel manufactures from corrosion. Iron does not rust because of catholic protection offered by zinc coating, that's oxidizing before steel.
. Degreasing cleaning - It is important that the material surface is properly cleaned, prior to galvanising. The expected life of hot-dip galvanised products is mainly affected by this process. To ensure a perfectly cleaned surface and that there is an absence of any substance (such as oils, grease, soil, soluble paint, etc) that will react with the zinc coating, the material is immersed in a degreaser tank which contains detergent additives.
. Rinsing - In this process, the material is rinsing in water to remove residues or deposits arising from the initial degreasing process.
. Pickling - Next, a hydrochloric acid solution is used to remove rust or scale from the steel material.
. Rinsing - Another round of rinsing occurs, to flush out any time of residues that are present from the previous pickling process.
. Fluxing - Zinc ammonium chloride solution is used for final cleaning of the steel product to prevent the clean steel from oxidation.
. Drying - A drying process is being carried out to prevent splashing during the dipping process.
. Zinc bath - The final product is immersed into the molten zinc with a temperature of 450°C.
. Cooling - A quenching tank is used to cool the steel products after the hot-dip galvanising process.
. Inspection - Upon completion of the process, all products undergoes a stringent quality control checks as well as laboratory tests on its coating thickness, adherence or uniformity of the coating as well as the physical appearance of the end product.
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