Various types of Steel that are available stainless, galvanised and thier applications

Steel is chemically an alloy of iron, carbon and other trace elements. Although carbon is the preferred element for blending with steel; nickel and tungsten are added to improve the quality of steel. Stainless steel and galvanized steel are the most common forms of steel available, and steel is graded into various categories depending on its composition. Stainless steel and galvanised steel are produced by entirely different chemical processes and stainless steel is perhaps the most widely used form of steel. Stainless steel is an iron-carbon alloy with 10.5% chromium; on the other hand, galvanised steel is basically steel coated with zinc to increase its durability.
A popular method of producing galvanized steel is called hot dip galvanisation. Hot dip galvanization is a process that involves passing steel through a molten bath of zinc. The zinc goes through a series of chemical reactions and chemically bonds with the steel, forming a surface coating of zinc and steel. Contrary to popular belief, galvanized steel can be used pretty much like regular steel and popular applications of galvanized steel include steel sheets, l-beams and automobile chassis.
Compared to ordinary steel, galvanized steel is rust proof and is ideal for extreme weather conditions. Galvanized steel is used for roofing and walling, making heating and cooling ducts and metal pails. Individual items like steel girders or wrought iron gates can also be hot-dip galvanized by a process called batch galvanizing. Today, hot dip galvanization has been replaced by more energy efficient and convenient techniques like electrogalvanizing.
Electrogalvanizing involves electroplating zinc on to steel and results in a thinner layer and stronger bond. Galvanized steel is still produced using hot dip galvanization but individual items like steel girders are usually galvanized using electrogalvanizing. Although stainless steel is supposed to be rust proof, there are numerous chemical and environment factors that can cause corrosion and cracking of stainless steel. Galvanized steel is thus the preferred form of steel for construction and automobile chassis.
Both techniques of galvanizing steel (namely hot dip and electrogalvanizing) have their unique advantages and applications. Although electrogalvanized steel is lighter and has a thinner coat of zinc, it is not ideal for extreme weather conditions or conditions where water will be in continuous contact with the steel. Electrogalvanized steel is used for making nails and smaller items that will not be exposed to extreme weather conditions. Galvanized steel has such a robust coating of zinc that it is used for making ship parts that are in continuous contact with salt water and the quality of galvanized steel is tested using a salt spray.
Galvanised steel also has aesthetic value as hot dip galvanization of steel produces a characteristic crystallization effect known as ‘spangle’. By adjusting the number of particles added and by regulating the rate of cooling, spangled steel can be produced with various effects. However, galvanized steel with spangles is rarely used for purposes other than statues and modern art.
In a nutshell, both stainless steel and galvanized steel have their unique properties and the choice of which steel to use is based on the area of application.

About the Author

Norman Sobol the author of this article on cold rolled steel. Find more information about cold rolled steel sheets here.