Stainless steel is the name of a high alloy steel used mainly for its anti-corrosion properties. The main characteristic of the stainless steel family is that they all contain a minimum of 10.5 percent of chromium. This enables the steel to withstand corrosive atmospheres or erosive chemical environments. There are over 60 different grades of stainless steel that is divided into 5 different categories. Stainless steel is more expensive than carbon and alloy steel and only accounts for a small number of steel used in the global market, but it is non the less a very valuable international market.
Stainless steel does not readily corrode, rust or stain with water as ordinary steel does, but despite the name it is not fully stain-proof, most notably under low oxygen, high salinity, or poor circulation environments. There are different grades and surface finishes of stainless steel to suit the environment the alloy must endure. Stainless steel is used where both the properties of steel and resistance to corrosion are required.