Stainless steel (corrosion-resistant steel) is an alloy steel that is resistant to corrosion in the atmosphere and aggressive environments, and has heat-resistant properties. Various grades of stainless steel include chromium, nickel, carbon, nitrogen, aluminum, silicon, sulfur, titanium, copper, selenium, niobium, and molybdenum.Stainless steels are divided into three groups:corrosion-resistant steels - they are required to be resistant to corrosion in simple industrial and domestic conditions (they can be used to manufacture equipment parts for the oil and gas, light, and mechanical engineering industries, surgical instruments, household stainless steel utensils and containers);heat-resistant steels - they are required to be heat-resistant - that is, resistant to corrosion at high temperatures in highly aggressive environments (for example, in chemical plants and thermal power plants). As a rule, these are complex alloy steels containing, in addition to chromium and nickel, tungsten, niobium, molybdenum, vanadium, titanium and other metals;heat-resistant steels - they are required to have heat resistance - that is, good mechanical strength at high temperatures.