Stainless steel is a steel alloy in which metal is added like chromium, nickel and molybdenum. Because of an extremely thin but very strong oxide layer on stainless steel, the material is durable, strong and there is no corrosion (rust). However it is not indestructible. If the material comes into contact with iron or iron particles (e.g. by welding, grinding) it can damage the protective coating and can lead to corrosion.
Stainless steel is mainly used in areas that are used intensifely and where hygiene is important.