Stainless steel is essentially low carbon steel which contains chromium at 10% or more by weight. It is the addition of chromium that gives the steel it’s unique stainless, corrosion-resisting properties. The chromium content of the steel allows the formation of a tough, adherent, invisible, corrosion-resisting chromium oxide film on the steel surface. If damaged mechanically or chemically, this film is self-healing, provided by that oxygen, even in very small amounts, is present. The corrosion resistance and other useful properties of the steel are enhanced by increased chromium content and the addition of other elements such as molybdenum, nickel, and nitrogen. There are more than 60 grades of stainless steel. However, the entire group can be divided into four classes. Each class is identified by the alloying elements which affect its microstructure and for which each is named.
- Corrosion Resistance– Chromium is the alloying element that imparts to Stainless Steel corrosion-resistant qualities. Lower alloyed grades resist corrosion in atmospheric and pure water environments; high-alloyed grades are capable to resist corrosion in most of acid, alkaline, and chlorine bearing environments making stainless steel useful in the plant production process.
- Fire and Heat Resistance– Special high chromium and nickel-alloyed grades resist scaling and retain high strength at high temperatures. Stainless Steel is used extensively in heat exchangers, super-heaters, boilers, feedwater heaters, valves, and main streamlines as well as aircraft and aerospace applications.
- Hygiene– Cleanliness is a matter of high importance. The easy cleaning ability of stainless makes it the first choice for strict hygiene conditions, such as hospitals, kitchens, and food processing plants.
- Aesthetic Appearance– The bright easily maintained surface of stainless steel provides a modern and attractive appearance.
- Impact Resistance– The austenitic microstructure of the 300 series provides high toughness at elevated temperatures ranging far below freezing, making these steels particularly suited to cryogenic applications.
- Strength-to-Weight Advantage– The work-hardening property of austenitic grades, that results in a significant strengthening of the material from cold-working alone, and the high strength duplex grades, allow reduced material thickness over conventional grades yielding considerable cost savings.
- Ease of Fabrication– Modern steel-making techniques mean that stainless can be cut welded, bent, formed, machined, assembled, and fabricated as readily as traditional steels.
- Long-Term Value– In considering total cost, it is appropriate to consider material and production cost AND the life cycle cost. When the total life cycle costs are considered, stainless is often the least expensive material option. The cost-saving benefit of a maintenance-free product having a long life expectancy.
- 100 % Recyclable– Over 50% of new stainless comes from old remelted stainless steel scrap, thereby completing the full life cycle.