What is hot dip galvanising?
Hot dip galvanising is a popular process used to prevent steel from corrosion. Before the process can be carried out, however, the steel needs to be chemically cleaned to remove all traces of oil, rust, and mill scale from its surface. Once this has been done and the cleaning solution rinsed off, the coating process can begin.
The steel is dipped into a bath of molten zinc at a temperature of around 460°C after which it’s removed and left to cool off in a quench tank. Once it’s totally cool the zinc coating is metallurgically bonded to the steel.
Why Use Hot Dip Galvanising?
Hot dip galvanising provides many benefits and below you’ll find 10 good reasons to use it.
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Lower first cost – galvanising has a lower initial cost than other forms of anti-corrosion protective coatings for steel since it is a mechanised process as opposed to painting which is extremely labour intensive.
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Long life – Galvanising produces a surface which is easy to clean with a maintenance free life expectancy of up to 50 years (depending on the environment in which it’s being used). When it eventually becomes time to maintain it, this is pretty straightforward and doesn’t involve any complex preparations
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Low longer-term cost – Its low initial cost and long life make galvanising a versatile and economic long-term method of protecting steel. The bonuses include very little maintenance (if any), easier to access in difficult terrains, remote areas, and closely packed areas, as well as in areas where there are safety restrictions such as electricity pylons.
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Reliable – the galvanisation procedure is straightforward and closely controlled. The weight or thickness of the coating is predictable, regular, and simply specified since it conforms to AS4680:2006.
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Speedy application – While a complex paint system could take up to a week, hot dip galvanised protective coatings can be applied in just a few hours.
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Toughness – Galvanizing is different to other types of coatings because it’s bonded metallurgically to the steel which means it offers the greatest resistance to damage when being mechanically handed, stored, and transported, used in construction.
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Complete coverage – Because it’s dipped, all parts are protectively coated including outside, inside, awkward corners, and narrow gaps which other forms of protection would be unable to reach. Furthermore, the coating actually builds up in those vital areas as opposed to thinning out when being applied by brush or sprayed, for example.
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Faster construction – Galvanised steel is ready to be used right away. There is no further preparation required, touch up, or inspection. Once constructed, the steel can be used and cladding can begin, making the construction process that much quicker.
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Easy to inspect – It’s easy to inspect the finish of galvanised steel – if the coating appears sound and continuous, then usually it is!
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3-way protection – galvanisation protects steel in 3 ways. Firstly, it gives a long a predictable life because it weathers slowly; secondly, because of its sacrificial protection any areas exposed by cutting, drilling, or accidental damage are sealed by the weathering products of the zinc; lastly, if the damaged area is larger the sacrificial protection prevents rust from creeping sideways which would undermine coating of paint.
So there you have it… 10 reasons to consider hot-dip galvanised steel when looking for that all-round protection.
For further information about the galvanisation process, or if you have a fabrication project that needs completing contact Metro Steel. We’ve been in the industry for many years and have the skills and the knowledge to execute your plans both quickly and efficiently. Contact us on 07 3204 1000 or come and see us at our Kabi Circuit Fab Shop and put us to the test.