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Galvanised Steel Withstands Corrosion
Galvanised steel is obtained by passing the metal through a molten bath of zinc at a temperature over 450°C. The zinc coating oxidizes to zinc oxide that further reacts with atmospheric carbon dioxide to form zinc carbonate. The zinc carbonate coating so formed is seen to prevent further corrosion of the metal that it covers.
During galvanizing, the zinc reacts with the iron in the steel to form a series of zinc/iron alloy layers. Thus, it is not just a coating that is formed on the top layer. The top layer consists of almost entirely of zinc; the intermediate layers are a mixture and the internal layer is pure steel.
Lead is usually added to the molten zinc during galvanizing to improve its flow. This prevents excess zinc accumulation on the galvanised product.
Galvanised steel is used in applications where corrosion resistance is important. Such steel shows amazing resistance to saltwater and moisture. It is thus popular as a fabrication component.
Steel is galvanised through the hot-dip galvanizing process. Such steel can be welded and used for high temperature applications. This steel can be used for roofing and walling applications. A common use is in coating metal buckets.
Hot-dip galvanizing has been used for more than a hundred years as an effective method against corrosion control. Studies have shown that hot dipped galvanised steel components greater than 1/4-inch thick can remain maintenance-free for more than 70 years in an industrial environment.
Steel can also be electrogalvanised. This kind of galvanised steel is used extensively for automotive parts. Batch galvanizing, a modern technique, is being used to galvanize objects like wrought-iron gates and girders.
aSteel is mostly galvanised after being formed into shapes. However, galvanised steel withstands a minimal amount of bending and forming without flaking of the zinc. Steel pipe
aGalvanised steel is also popular because of the fact that it can be recycled and reused many times.
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