A Quick Guide to Galvanised Steel
30 March 2022
Anyone interested in ordering steel online from local suppliers needs to take the location of their site and the requirements for their products into account.
One particularly crucial point to be aware of is the reliability and durability of the required universal beams, channels or columns. If you require structural steel fabrication and products which require a high level of corrosion resistance, your best bet may be to use galvanised steel.
If you have any queries about what galvanisation is or how it can benefit you, continue reading this blog post from Buy A Beam to learn the answers to your questions.
What is Galvanising?
Galvanisation is a commonly used method to prevent the buildup of rust on steel products, which involves applying a thin coating of zinc to the surface of a metal which helps to protect against rusting and corrosion. Contrary to popular belief, galvanised steel sheets are not the same as stainless steel sheets.
Once you understand what galvanised items look like (typically those with a muted silver colouring), including lamp posts and road signs, you’ll probably notice other similar products which have undergone the process of galvanising.
Why is Galvanisation Used?
The corrosion resistance created by galvanising a steel product is vital to the product’s longevity, especially when exposed to certain elements. This is due to steel being a ferrous metal, which refers to the inclusion of iron in the metal’s chemical composition. As iron begins to rust when exposed to water, structural steel fabricators rely on methods such as galvanisation to keep the rust away and, in turn, maintain the natural physical performance properties and aesthetic benefits of steel products.
How does Galvanising Work?
Structural steel fabricators regularly use galvanisation because it's a technique that provides well-rounded corrosion resistance to any products that are at risk of developing rust.
There are two main ways this metal fabrication process helps reduce the risk of corrosion.
Protective Coating
The process of galvanising steel creates a protective layer of zinc on the surface of the metal. This, in turn, reduces the chance of heavy rainfall from reaching the base steel and causing it to oxidise.
Unfortunately, layers of zinc can wilt away if the steel is not properly handled, thus rendering the rust protection useless. This is why it’s crucial to handle the galvanised steel correctly.
Reducing Galvanic Corrosion
An additional benefit of galvanisation that not many customers are aware of is that it reduces the risk of galvanic corrosion. This occurs when an electrolyte corrodes one of two metals joined together (such as zinc and steel in the case of galvanised metal products).
Galvanising with zinc reduces this issue, as the chemical composition of zinc means it’s much more likely to be the element that corrodes, therefore preventing the steel underneath from suffering the same fate.
What Galvanising Processes are Available?
Once the decision has been made to use galvanised steel, you need to determine which type of galvanisation is best for your steel fabrication request and whether your chosen online steel suppliers can use it.
There are three commonly-used methods of galvanisation, all of which offer excellent levels of corrosion resistance:
Hot Dip Galvanising
This process involves dipping the required steel into a bath of molten zinc, forming a metallurgical bond that results in a firm layer of pure zinc. The success of this method relies on a rigorous cleaning process, removing any impurities and ensuring an even zinc coating is produced.
Pre-galvanising
This option is similar to hot-dip galvanising but is instead completed on sheet metal within a steel mill. Cleaning is required before the steel item is passed through a bath of molten zinc.
Electro-galvanising
As its name suggests, this galvanisation method involves using an electric current to transfer zinc ions onto the steel within an electrolyte solution. A vital benefit of this technique is that it creates an even coating on the steel. Still, the zinc layer is thinner than that produced using hot-dip galvanisation and has a shorter life expectancy.
Which Galvanising Process Should You Choose?
This decision depends on the specifics of your project and the tasks your galvanised steel will be used for. All three methods introduced above can create excellent results, so the best way to understand how they could all affect the longevity of your products is to contact local steel fabrication companies and learn about the options they provide.
Order Galvanised Items from Online Steel Suppliers
Buy A Beam’s online store is a brilliant way to contact online steel suppliers local to your site. You can browse items, use a structural steel beam calculator and place an order for galvanised steel at any time of day. If you’re looking to buy structural steel online today, Buy A Beam is the place to start.