Rainbow Industrial Estate Station Approach Off Grand Drive Raynes Park SW20 0JY

Hot Dip Galvanisation


Posted on March 15, 2017 by admin



In this blog we are going to take a look at galvanisation – what does it do, how is it done, and how Surrey Steels can offer you galvanised steel.

What is Galvanisation


Galvanisation is a process whereby steel has a zinc layer added to the beams to create a protective coating. This coating is incredibly resilient, ensuring that the steel does not rust as quickly as unprotected steel. This is a much more effective process than painting the beams, as the protective coating covers all surfaces of the beam and is even effective when the zinc is damaged and the steel underneath exposed.
How is Galvanisation Done?

The most common form of galvanisation is a process called hot dipping. It is very much like it sounds – the steel is submerged in a tank with molten zinc, and the zinc sticks to the beams to create the protective coating.
There are a few simple stages here. First the beams are cleaned with a cautic solution to ensure they are free of grease and dirt. An acid is then used to remove mill scale on the beams. A flux is then added to the beams to ensure a good bond between the zinc and the beam, which is then applied via the dipping method. The beams are then cooled quickly to ensure a good finish and prevent any undesirable reactions with the metal.
The advantages of this process are that it is much cheaper than using stainless steel, but also more resilient than standard paints, which are ineffective as soon as they are chipped or exposed back to the metal underneath.

Galvanic Corrosion


The reason galvanised steel is more resilient to corrosion than standard protective paints is due to a process called galvanic corrosion. Amazingly, when the zinc layer on galvanised steel is exposed by damage or wear, the surface underneath maintains its resistance to corrosion. This is because the zinc around the damaged area is electropositive, which means that the zinc prevents the steel from reacting with moisture and the air.

Can I get Galvanised Steel from Surrey Steels?


Absolutely. Surrey Steels offer several different finishes for your steel. We can coat the beams in a protective paint, apply a fire retardant paint, provide the steel unprotected, or provide galvanised steel. We are happy to quote for any of these products – so just ask our sales team for more information or a quote.
 


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