The process of applying a layer of zinc to steel to protect it against rusting and corrosion is known as galvanising. Galvanised steel can be used for the construction of structures and help to lower the costs of repair and maintenance. If it is not protected, moisture and atmospheric conditions will cause steel to rust to some degree, depending on its environment. Steel can be protected by other methods, such as plastic coating or painting, but these are less effective than galvanisation. When a plastic coating or a layer of paint becomes damaged, the exposed steel can corrode and become weaker, but galvanisation covers the steel completely with a coating of zinc.
What is hot-dip galvanisation?
There are two methods of galvanisation: electro-dipping and hot-dipping. The hot-dipping method is the preferred option. In this method, the metal to be treated is dipped into a bath of molten zinc. The metal is completely immersed in the zinc, which is at a temperature of approximately 450°C or 842°F. The process bonds the zinc metallurgically to the steel and protects all its surfaces against corrosion. This process is not only relatively environmentally friendly, but it also offers long-lasting protection against rusting.
Because zinc corrodes very slowly, it provides long-term protection. The zinc is bonded to the steel, where acts as a sacrificial metal. The steel benefits from cathodic protection, which means that any exposed areas will not be affected by rust. Exposed areas of steel do not need touching up in the same way that they would if the surface was painted or had a plastic layer applied.
According to the Galvanizers Association, the first patent for the process of dipping steel in molten zinc to coat it was carried out in 1836 in France by chemist Stanislaus Sorel, who gave it the name “galvanising”.
Uses for galvanised steel
There are many uses for galvanised steel, including for ductwork parts in air conditioning systems and other applications where environmental conditions would cause unprotected metals to corrode over time. These parts are available online from https://www.dustspares.co.uk/ductwork-parts/, and they need less maintenance than parts in other materials.
Galvanised steel parts also have a long life expectancy and the added advantage of being more affordable than stainless steel. One further advantage with galvanisation is that surfaces require less preparation, maintenance and inspection.