It is said that stainless steel was a “happy accident” discovered in 1913 by Sheffield metallurgist Harry Brearley who was experimenting with different types of steel for weapons. He then noticed that a 13% Chromium steel had not corroded after several months. Initially called “rustless steel”. It was first referred to as “stainless” after experiments proved that the steel could not be stained with vinegar.
Stainless steel is an alloy of Iron with a minimum of 10.5% Chromium. Chromium produces a thin layer of oxide on the surface of the steel that prevents the surface from corroding. The more Chromium, the better the resistance to the corrosion. This film rapidly self-renews in the presence of oxygen. Any damage by abrasion, cutting or machining is quickly repaired. This layer is described as passive, as it does not react with or influence other materials, and tenacious, as it is strongly attached to the steel and is not transferred elsewhere. This means that it will not contaminate anything that comes in contact with it. Stainless steel is an extremely low maintenance material. It also has strong aesthetic qualities as it can be polished to a satin or mirror finish achieving a clean and minimal design.
Stainless steel may also contain varying amounts of Carbon, Silicon and Manganese. In order to achieve other useful properties such as formability and increased corrosion resistance, elements such as Nickel and Molybdenum may be added as well.
Stainless steel is usually divided into 5 types:
- Precipitation hardening (PH)