Should You Choose Galvanised Steel or Stainless Steel
16 September 2022
Stainless steel and galvanised steel are both forms of steel that provide protection from rusting and other corrosion. They work to protect the underlying metal from damage. Galvanised steel does this through a protective coating applied after fabrication whilst stainless steel uses other metals such as chromium that forms a ‘passive layer’, providing corrosion resistance.
The Difference Between Stainless Steel and Galvanised Steel
Galvanised steel relies on a protective coating added to steel to provide resistance against corrosion and rust; stainless steel contains small amounts of other metals that apply this corrosive resistance throughout the steel.
What is Stainless Steel?
Stainless steel is a form of steel that is mixed with chromium and other alloying elements that create a strong resistance to corrosion throughout the material. The chromium is added to the steel during the initial melting process, which occurs before the metal is formed into the structure it will later become.
What is Galvanised Steel?
Galvanised steel is steel coated in a layer of galvanise, a zinc coating that provides resistance to corrosion and rust, whilst this outer layer remains intact. This can be a relatively cost-effective way to protect your steel from rusting or corroding.
How Does Stainless Steel Resist Corrosion?
When steel rusts, the iron present in the structure binds with the oxygen present in the air to form iron oxide. However, the chromium and other alloying elements present in stainless steel protect the underlying structure through a chemical process called passivisation. Passivisation allows chromium oxide to form on the structure's surface, coating the iron and preventing the oxygen in the atmosphere from binding to it.
How Does Galvanised Steel Resist Corrosion?
The zinc coating applied during galvanisation forms a layer that protects the underlying steel from corrosion and rust. The zinc layer serves two different purposes; both are useful for resisting.
Firstly, the zinc coating greatly reduces the chance of rust through fully encapsulating the steel and reacting with any oxygen that it comes into contact with. On top of this, if the zinc coating is chipped or damaged, the zinc will still provide protection from rusting as zinc is more reactive than the iron in steel, meaning the oxygen will bind with the zinc molecules to form zinc oxide before it binds to the iron.
Applications of Stainless Steel
Stainless steel tends to be the more expensive option for large-scale applications. However, it is primarily used in instances where added protection to corrosion is needed, such as aerospace engine components, pharmaceutical manufacturing equipment and food processing equipment.
Applications of Galvanised Steel
Galvanised steel is a much more cost-effective method of helping steel against corrosion and rust. Some key applications include structural steel beams and columns, ducts, railings and automotive components.
Which Type of Steel Stands up Better, Galvanised or Stainless?
As always, the best choice comes down to the application. Stainless steel can be a much more durable option. However, in large-scale applications, the cost of this will often largely outweigh the benefit. Galvanised steel will often reign king in building projects where steel is used. This is because it’s a very cost-effective way to protect steel from corrosion at a much larger scale than other methods.
Order Steel Online from Local Steel Suppliers
If you’d like advice on which form of steel is right for you, or if you know what you need and want access to high-quality steel elements for your upcoming construction project, look no further! Buy A Beam’s store enables you to reach local, skilled fabrication experts that can provide you with structural galvanised steel or stainless steel elements for your construction projects.