Galvanized steel is metal that undergoes the galvanization process. The galvanization process is the process of applying a thin coating of zinc to different types of metals. Different methods are used to galvanize metal, including hot dipping, pre-galvanizing, and electro galvanizing.

You can tell that metal is galvanized when it has a pattern to it that is known as a spangle pattern. Carbon steel is the most common type of metal that we galvanized.

Different methods of galvanizing

When steel is brought into contact with molten zinc, a chemical reaction takes place, which bonds zinc on the surface of the steel. Thus, a zinc layer over steel acts as a layer that protects it from being corroded. The most common method of applying a zinc coating over steel is hot dip galvanization; however, there are various other processes that are also used for galvanizing steel, such as:

Hot dip galvanization – In this method, a steel sheet is dipped in a bath of molten zinc kept at a temperature of 860°F (460°C). When the steel comes into contact with this molten zinc, an iron zinc alloy is formed and when the steel sheet is taken out in a normal atmosphere, zinc oxide is formed, which prevents corrosion.

Zinc electroplating – In this method, a steel sheet is dipped into the zinc ion solution and an electric current is passed through it, which uniformly spreads the zinc ion solution on the metal sheet.

Mechanical plating – In this method, zinc powder, along with glass beads and a special reducing agent, are coated on the steel sheet, which bonds zinc particles on the surface of the sheet.

Sherardizing – In this method, a steel sheet is heated up to a temperature of 752°F (400°C) and passed through zinc powder. At this high temperature, diffusion between zinc and steel molecules occurs.

Continuous strip galvanizing and galvanized wire – In this method, a steel strip or steel wire is passed through a solution of molten zinc at a high speed of 590 feet (180 meters) per minute in a controlled air pumping. This applies a zinc coat on the metal sheet.

Zinc metal spray – In this method, a steel sheet is cleaned to Class III level, and then zinc powder is sprayed on top of it with the help of a plasma flame gun.

Advantages of Galvanized Steel

Rust Resistance: Iron in steel is incredibly prone to rust, but zinc acts as a protective buffer between moisture, oxygen, and steel.

Easy Inspection: It’s fairly simple to tell how strong a galvanized coating is, just by looking at it. Quick stress tests can tell you how thick the zinc is.

Galvanizing is Cost-effective: The true cost of protecting steelwork from corrosion has to take into consideration two important elements, the initial cost of protection and the lifetime cost.

Sacrificial Anode: This ensures that any damaged steel is protected by the surrounding zinc coating. It doesn’t matter if the steel section is completely exposed; the zinc will still corrode first.

Galvanizing is Durable: A galvanized coating is one of the most durable forms of corrosion protection on the market. An average coating thickness of 85 microns, the same thickness as a sheet of A4 paper, can protect a steel structure for the better part of 50 years.