Stainless steel or stainless steel is the name given to the currently high chromium content steels, for their property of not rusting when exposed to air and water: the chromium, oxidized in contact with oxygen, is transformed into oxide chromium (CrO2) that adheres to the workpiece, preventing further oxidation (this phenomenon is known as passivation). I am an extremely important class of steels, used for many different purposes: from their discovery in 1913, thanks mainly to the subsequent progress of the metallurgy between the 40s and 60s, have extended their development and their applications; still they are refined and adapted to the demands of various industries, such as oil / petrochemical, mining, energy, nuclear and food.
For less demanding applications, you can use carbon steels only, otherwise you need to add alloying elements to increase the hardness.
Carbon: 0.6% concentration could already offer maximum hardness, however, some of the carbon combines with other elements present and therefore may be necessary to increase the content.
Manganese: has deoxidizing action, improves the hardenability and facilitates the formation of carbides.
Silicon: has deoxidizing action, increases to ‘oxidation resistance.
Chromium: increases the hardenability, stabilizes the carbides.
Vanadium:prevents the grain growth, beneficial to have high-temperature hardness.
Tungsten and molybdenum: voted for the resistance to ‘wear at high temperatures.