Galvanization is a process which includes applying a protective layer of zinc coating to steel iron or steel which protects the metal from rust and corrosion. Without protection, steel and iron will rust and corrode due to the atmosphere. For outdoor, underwater, or industrial applications, galvanized steel is one of the most essential fabrication components.
What Is the Galvanising Process?
Preparation of Work for Galvanising
It is important to ensure that material to be hot dipped galvanized is absolutely clean for the molten zinc to create a great metallurgical bond with the material. To make sure that the material surface is clean, the material is processed through a pickling process before experiencing the galvanizing kettle. This process helps remove any scale, paint, rust, and oil from the surface of the steel with suitable treatment followed by acid cleaning in sulphuric acid, followed by rinsing.
The cleaned steel piece is dipped in a flux solution, which is generally 30% zinc ammonium chloride with wetting agents, maintained at the temperature of around 65◦C. The solution washes away the oxide film from the steel piece which forms on the highly reactive steel surface after acid cleaning. The steel piece is then dried for the process of galvanizing.
The steel surface is dipped in the molten zinc which reacts to form a series of zinc-iron alloy layers. The period of immersing steel piece in the solution varies from several minutes up to half an hour or longer for larger steel pieces. The final coating is long-lasting and tough providing unmatched resistance to abrasion.
Benefits of the galvanizing process:
Lowest cost – Galvanizing is less expensive as compared to many other protective steel coatings. The application cost of labor intensive coatings like painting has increased rapidly in the past.
Less maintenance – Galvanized coating lasts longer than other types of coatings and it needs less maintenance. Higher maintenance adds to costs when steel structures are situated in remote locations.
Inspection – Galvanized coatings are quite easy to inspect by eyes, and easy non-destructive thickness testing methods can also be used.
Toughest coating – A galvanized coating has an exceptional metallurgical structure which makes the steel resistant to mechanical damage during transport and service.