This is material with a chrome content >10.5% and carbon <1.2%, elements needed to create, in contact with the oxygen present in the atmosphere or in water, a corrosion-resistant layer (layer known as passive), from which its stainless qualities derive.

Stainless steels are particularly resistant to oxidation and corrosion phenomena. The addition of elements such as molybdenum, the different amount of carbon or the treatment with titanium generate the different types of stainless steel, each of which has different qualities and a specific resistance property, which determine its applications and practical uses. Stainless steels are distinguished by their characteristics and properties through the conventional Aisi (American Iron and Steel Institute) nomenclature. Aisi identifies 5 series of stainless steels, including the austenitic chromium-nickel and chromium-nickel-molybdenum steel series, identified by the number “3”, followed by two digits and, possibly, a letter such as “l” ( which shows a corresponding but “low carbon” alloy, that is, with a lower carbon content “.