Cleaning the galvanized product is the beginning and the most important step of the whole process.
In fact, to ensure the best possible result of galvanizing or other type of galvanization required, the material to be treated must be completely free from impurities which would otherwise be uniformly covered.
The first stage of cleaning products is degreasing: any machining residues, oils, lubricants and greases must be completely eliminated by means of baths containing chemicals which, by emulsion, allow detachment from the object.
It is important that the galvanized product comes to the uncontaminated galvanizing phase: on the contrary, if this did not happen, the subsequent treatments and the final result would be compromised, with any defects in uniformity of the protective film and less resistance over time.
Flushing creates a thin film of saline on the entire surface, which allows to lower surface tension and facilitate wetting between the two different metals.
The flow also protects the surface from oxidation when waiting for the next step.
Hot galvanizing: The artifact, hanging, is lowered and immersed in the molten zinc bath (in the case of galvanization, the temperature is about 450 °). It remains fully immersed for a time varying between 5 and 20 minutes according to the characteristics of the same.
Cold galvanizing: The artifact is hung, positively charged and immersed in a chemical bath where the protective material is present which, negatively charged, is attracted to the article and distributed evenly throughout the surface.
Metal pieces, though no longer immersed in the galvanizing bath, are still at high temperatures and the chemical process continues. To stop the process being processed, the artefacts are cooled with a mixture of air and water.
The treatment is needed to avoid the so-called “white rust” that would form and compromise the aesthetics of building-architectural constructions, for example. It is to be specified, however, that this “white rust” does not absolutely affirm the strength and effectiveness of the underlying protective film.
With the passivation process, galvanizing treatment can be considered complete.
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