The term stainless steel generally refers to iron alloys containing chrome, in quantities varying from 11% to 30%. It is the addition of chrome that gives the steel its resistance to rust and corrosion, thanks to a thin, invisible film that covers the surface of the material and self-repairs if damaged.
Stainless steel was discovered in 1872 when Woods and Clack patented a special iron alloy. However, it wasn’t until 1913 that the material was perfected and mass produced when Harry Brearley discovered that this particular type of steel did not rust when exposed to the elements.
Initially stainless steel was used for cutlery and fire arms, though once the metal industry expanded, its applications greatly increased.
Other binders may be nickel, copper, titanium, molybdenum, and niobium. The total quantity of these should not be greater than 50%, otherwise the product is no longer considered stainless steel, rather it becomes austenitic steel. The variation of each binder affects the structural and mechanical qualities of the steel, as well as its resistance to corrosion.
A steel that is made of iron, chrome, carbon, and other elements like nickel and molybdenum, is known as stainless steel 316L. Thanks to the increased levels of nickel, this stainless steel is greatly resistant to corrosion and the effects of acid. It is an ideal material for welding and requires no treatment.
The chrome in the stainless steel means that the steel is stable and elastic, thereby increasing its malleability. Its melting temperature is 1435 ° C, though during welding when the temperature reaches between 600 and 800° C the stainless steel transforms from an austenitic to ferritic structure. Thanks to its exceptional properties, stainless steel is often used in architecture, as well as the petrochemical, food, pharmaceutical, chemical, paper, and textiles industries, which is precisely the subject we will tackle in our next Focus article.