Today’s environment exerts immense pressures on product material requirements. Products must withstand a diversification of atmospheric conditions, such as, high pollution, marine locations, and high humidity climates. Additionally, one must protect the product against cleaning agents/solutions and ideally the product should offer hypo-allergenic properties.
Stainless steel is “a general description for a group of steel products that consist of a minimum of 12% chrome in conjunction with varying quantities of nickel, molybdenum, titanium and carbon”Stainless steel is renowned for the following two properties: resistance to corrosion and low maintenance requirements.
Stainless steel corrosion resistance is attributable to the presence of a thin, durable film of passive, but stable, chromium oxide. Being inserting, invisible, extremely adherent and self-repairing, this film provides an unrivalled protection for the steel; should the film be damaged or removed it will reform independently, provided that oxygen is present to allow the reaction to occur with the chromium content or the steel. Thus the necessity to ensure regular cleaning maintenance.
There are several types of stainless steel, all of which are corrosion resistant to differing degrees. The most common and important type within the stainless steel family is known as austenitic and contains nominally 18% chromium and 8% nickel, 18/8, resulting in improved corrosion resistance.
The advantages of this particular type are twofold: temperatures of – 160 deg.C up to melting point of the steel (approximately 1450deg.C) can be withstood and offering the best protection corrosion-wise.
Within the austenite group two particular grades are of particular interest, known as AISI:
- 304, possesses the property of corrosion resistance in natural atmospheric environments, however, only non-acid based cleaning solutions can be used.
- 316 (an addition of an extra 2-3% molybdenum and nickel), has enhanced corrosion resistance suitable for