The complete guide to galvanised steel

The complete guide to galvanised steel

Galvanised steel is one of the most commonly used metals in industry. It’s used both indoors and out and is known for its reliability and weather resistance.

But what is galvanised steel? How is it made? How is it used?

If you’re planning a project and are wondering whether to use plain steel or galvanised steel, this guide can help.

We’re going to explain what galvanised steel is, how it’s made, its key properties and how you can use it.

What is galvanised steel?

Galvanised steel is standard steel that has been galvanised with a thin layer of zinc to protect the metal underneath.

That layer of zinc is hard and almost impermeable. It helps reduce the risk of rust and reduces the potential for staining and discolouration.

How is galvanised steel made?

Galvanised steel is created using galvanisation. There are several ways you can do it but the most popular is hot-dip galvanising.

This is where the steel is dipped into a bath of molten zinc. The zinc adheres to the steel forming layers of zinc-iron alloy on the surface.

The adhesion is so complete that there is very little separation between the steel and the zinc. The layer is total, with very few holes or areas where rust or the environment can get at the steel, which is why it’s so robust.

The galvanising process looks a little like this:

  1. The steel is formed and thoroughly cleaned to remove dirt and debris
  2. The material is then pickled, dipped into a bath of hot sulfuric acid
  3. It’s then fluxed, dipped into a bath of zinc-ammonium chloride
  4. The steel is then dipped into a bath of molten zinc to galvanise it
  5. The steel is then removed from the bath and inspected to ensure complete coverage
  6. It’s then allowed to air dry

Once dipped, the steel is removed from the hot-dip bath and allowed to dry naturally.

As it dries, the zinc forms zinc oxide (ZnO) and zinc carbonate (ZnCO3). Both of which provide a very effective barrier that fully protects the steel underneath.

There are other types of galvanisation, galvannealing, thermal diffusion galvanisation, electro-galvanisation and a few others, but hot-dip galvanising is by far the most popular.

The advantages of galvanised steel

We alluded to some of the primary advantages of galvanised steel earlier, but let’s discuss them a little more.

Long operating life – As galvanised steel is protected from the elements and oxidisation, it has a long operating life. It isn’t unusual for galvanised steel to still be fully functional in excess of 50 years later, even in harsh environments.

Low cost – Relatively speaking, galvanised steel is a low cost material to use compared to other types of steel. The process does add to the initial cost but the lifetime cost is much lower as it needs very little preparation, maintenance or protection.

Resists rust – That zinc layer will be a complete layer, with no gaps or holes for moisture to reach the steel underneath. This helps galvanised steel resist rust much more effectively than plain or even painted steel.

Weather resistant – For the same reasons as above, galvanised steel can resist the worst weather the British climate can throw at it. The zinc layer makes galvanised steel almost impervious to wind, rain and sun.

Where is galvanised steel used?

As you can probably appreciate, galvanised steel has a lot of potential uses. It is used everywhere, across industries but can often be found in the following.

Renewable energy

Galvanised steel is used extensively in renewable energy as it’s predictable, consistent, requires little maintenance and has proven reliable.

In situations like wind turbines where the material is exposed to the elements, galvanised steel has more than proven its worth. It can also be used as frames for solar panels and a variety of uses.

Plumbing and heating

Galvanised steel is used in pipes, tubes, fixings, tools, air conditioning and some of the machinery used in both plumbing and heating.

The moisture resistance of galvanised steel makes it ideal for wet areas, which is why it’s used extensively within buildings.

Vehicle manufacture

The automotive industry uses a lot of galvanised steel for its rust resistance. The motor industry has fully adopted galvanised steel to avoid the reputation some car makers once had for rusting as soon as they were driven off the forecourt.

Now, almost every vehicle manufacturer uses galvanised steel for the body and chassis of vehicles.


The construction industry has also fully accepted galvanised steel. It is used in buildings to form part of the structure as well as air conditioning, some plumbing and heating uses.

Galvanised steel can often be used architecturally too. Installations, exposed ductwork, metal stairs, garden installations and other areas may use the material.


Galvanised steel is used throughout the telecommunications industry too. It’s often found in areas exposed to the elements where you see the most of this material.

Phone masts, aerials, equipment boxes, fixtures and fittings, satellite dish frames and other uses are just some of the ways it’s used.

Galvanised steel and its uses

Galvanised steel is a popular material used across industry because of its relatively low cost and low maintenance requirements.

It is also weather and corrosion resistant, making it ideal for use across industry and in areas exposed to a wide range of conditions.

Whether you’re considering using it for a home DIY project or in a multimillion dollar development, there are few better, more flexible materials to use than galvanised steel!

Speak to the experts at Buy Metal Online to get galvanised steel products that are made from high-grade metals and can be cut to size for free.


Share this post