Steel is used for so many applications and it is used in many different industries. It is a versatile material that is durable and can be used in different ways. Galvanisation is carried out to improve certain properties of steel and provide it with a measure of protection. Galvanisation is a process where a protective zinc coating is applied to the surface of steel or iron to withstand corrosion. Zinc is the material that is commonly used when adding a protective layer to ferrous metals such as iron or steel.
The methods by which galvanisation is carried out will differ according to the materials used and the thickness of the coating provided. Thermal spray is one such process. Here, a zinc wire is partly melted and this is then projected through compressed air into the surface that you are galvanising. This provides a very thick coating of zinc. Before a material is sent for galvanisation, it has to be prepared so that it receives the coating evenly and that the zinc adheres properly to the surface.
This will prevent any irregularities in the final finish and the material will last longer as well. One method of surface preparation is grit blasting where abrasive particles are fired at a high speed using compressed air to remove any impurities, dirt, or sand on the surface of the material. In hot dip galvanising, there is a pool of molten zinc in which the steel is immersed. There is a specific temperature for the molten zinc that is maintained throughout the procedure. Once the material is dipped into the bath, it will be pulled out which gives rise to a reaction between zinc and oxide particles in the atmosphere. This is what creates the zinc oxide layer at the end.
If you are looking for a method that provides a very thin layer of coating, electroplating is the solution. This is used for smaller-sized items that are used on a daily basis. This process includes a solution that is called the electrolyte which a constant current is passed through.
There is also a reservoir, zinc anode, plating station, rectifier, and ancillary tank used for the process. There are different materials that can be used to coat the surface such as cadmium. Zinc is not the only metal used for this purpose. An alkaline detergent is used to clean the surface to prepare it for electroplating. Acid treatment can ensure that all debris on the surface has been removed.
Sheet galvanising is a process used for steels sheets and wires. There is a thicker coating applied in this process compared to electroplating. The steel sheet is subjected to continuous pressure through a ribbon that is moving constantly. And this ribbon will apply a layer of zinc onto the surface allowing it to bond to each other. You can select the thickness that you require. Once the surface is prepared, it undergoes annealing so that the strength of steel is enhanced before galvanisation. This process is used for pipes, roofing materials, etc.