Stainless steel plays a major role in the hygienic preparation or storage of almost everything that we eat or drink. All modern vehicles boast stainless steel components in critical areas. For example: exhausts, safety belt buckles, airbag gas cylinders and catalytic converters. Increasingly, stainless steel is finding new applications in decoration, signage, shop fittings, architecture, furniture, appliances and technology.
Stainless steel is generally seen as a family of chromium-containing alloys. All these alloys contain at least 11 percent chromium. The chrome oxide layer on the metal is what makes stainless steel corrosion resistant. This layer is only about a micron thick, but it is incredibly strong and when it is damaged, it regenerates itself as long as there is oxygen available.
The main branches of the stainless steel family tree are martensitic, ferritic, austenitic and duplex type stainless steels. Columbus Stainless makes the most commonly used types: ferritics, austenitics and duplex stainless steel.
Ferritic stainless steels are plain chromium type steels containing 12% - 18% chromium, the balance being mainly iron. Austenitic stainless steels typically contain 18% chromium and 8% nickel, with the balance being mainly iron, while some austenitic stainless steels contain 2% molybdenum for enhanced resistance to pitting corrosion.
The duplex stainless steels have a microstructure, when heat treated properly, of nearly equal proportions of austenite and ferrite. This microstructure ensures that the duplexes are much more resistant to stress corrosion cracking (SCC) than austenitic stainless steels.