PREPARATION
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The galvanizing reaction will only occur on a chemically clean surface. Therefore most of the preparation work is done with this objective in mind. In common with most coating processes the secret to achieving a good quality coating lies in the preparation of the surface. It is essential that this is free of grease, dirt and scale of the iron or steel before galvanizing. These types of contamination are removed by a variety of processes. Common practice is to degrease using an alkaline or acidic degreasing solution into which the component is dipped. The article is then rinsed in cold water and then dipped in hydrochloric acid at ambient temperature to remove rust and mill scale. Welding slag, paint and heavy grease will not be removed by these cleaning steps and should be removed before the work is sent
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to the galvanizer. After further rinsing, the components will then commonly undergo a fluxing procedure. This is normally applied by dipping in a flux solution - usually about 30% zinc ammonium chloride at around 65-80°C.
Alternatively, some galvanizing plants may operate using a flux blanket on top of the galvanizing bath. The fluxing operation removes the last traces of oxide from the surface and allows the molten zinc to wet the steel.
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