The name stainless steel is given to a certain group of high tempered steel alloys that are resistant to corrosion. This high level of resistance is due to chromium oxide build up on the surface of the metal. Ordinary carbon steel corrodes easily from rain. This corrosion is seen as a brown oxide, which we call rust.

Once the rust begins it will eventually overtake an entire piece of metal. To reduce this, a coating that is 10% chromium is added. This then transforms the surface of ordinary steel into what we call stainless. There are several types or grades of stainless steel available for public use.

The simplest form of stainless steel is the one most commonly found in products like knives and razor blades. Basic steel is considered to be ferrite. The manufacturers increase the carbon content. This type of steel is harder to weld and is brittle. It is labeled type S42000 and is in the family of Martensitic steel.

Kitchen sinks are made form a different type of stainless steel, Austenitic. S30400 is also used in the production of building facades and food processing equipment and chemical piping. These are in the family of duplex stainless steels. They are created from 50% ferrite and 50% austenite. The most common duplex stainless steel is 2205 including both S31803 and S32205 and these are used for hot water tanks.

The higher the nitrogen content that is added to the ferrite and austenite makes it even stronger and this is the steel that seafaring tankers and naval ships. The amount of nitrogen needed to form this strong steel is 0.15%.

There is one more family of stainless steel and this is the one used in the aerospace industries and by manufacturers of equipment for the defense department. A typical example of this is S17400. These stainless steel products also incorporate other metals into their formulas for more structural integrity. These are the beams you will see used to put up skyscrapers.

A final thought about stainless steel is that it is recyclable. This makes it a green material, which has of late become very important in most countries. The grades that contain nickel can bring a lot of money if recycled. The beauty of this is that the recycling makes a new form of stainless steel that can be used to make different products. Most of the steel sold today has been made using the recycled steel of yesterday.