This article provides an overview of the galvanization process, which is found in all ferrous and nonferrous metals. The galvanization process is the application of a metal coating using molten zinc. The main processes, such as dipping, immersing, and electroplating, are established processes that protect steel products from corrosion caused by external harm and environmental damage.
Galvanization: a history
In the 1800s many scientists were interested in how metals and electricity behaved. In 1824, Sir Humphrey Davy was experimenting with the corrosive rates of dissimilar metals when immersed in water. He concluded that when two different metals were electrically connected whilst immersed in water, one metal would corrode more quickly whilst the other received some protection from corrosion. This knowledge was then used to preserve the hulls of wooden naval ships, as iron or zinc plates were attached to the copper bottoms.
In 1836, Stanislas Sorel applied for a patent for the process of cleaning steel and then coating it by immersing it in molten zinc. This has become known as hot-dip galvanizing.
Hot-dip galvanizing
The majority of zinc-coated steel in the world is produced using hot-dip galvanizing. In this process, zinc is supplied to a heated flux bath. The product to be coated is then moved through the bath, where it picks up a coating of molten zinc. You can find examples of galvanized wire at balingwiredirect.com.
This process usually takes place in a continuous or semi-continuous line and depends on conveying equipment and various alloys that are used to make the galvanized coating adhere to the base metal. After galvanizing, the product may be wet or dry, depending on whether deoxidants have been added.
Electro-galvanizing (plating)
Electro-galvanizing is a process where an electric current is passed through a tank containing a solution of zinc sulfate and the steel components that need protection. The parts are suspended on electrically conductive strings or rods.
The electric current deposits zinc from the zinc sulfate solution onto the steel as a protective coating of zinc. The parts are continuously lowered into the bath by an automatic feed system, and the current is passed through them using an external source connected to each string or rod.
Sherardizing
Sherardizing is a process where a zinc coating is formed on ferrous materials by rolling zinc powder onto the parts to be protected in a hot sealed drum. This leads to a protective zinc alloy forming on the surface of the component.
Zinc spray galvanizing
The zinc spray galvanizing process is where zinc in its powder form is sprayed onto the surface using a plasma flame. It is used when the shape of the component being protected is too complex for the hot-dip galvanization process.
The galvanization process involves using molten zinc to coat ferrous and nonferrous metals. This is used to prevent corrosion because zinc provides a sacrificial layer that protects the metal from degradation due to water, air, and other corrosive agents. The different processes for galvanization include hot-dip, electroplating, Sherardizing, and the zinc spray method. The hot-dip method is the most common galvanization process in use today because it is relatively cheap, but it uses high temperatures which can be dangerous.
