Stainless steels and their properties
Stainless steel is an iron-based alloy with at least 11-12% chromium and minimal carbon content. Most commercial grades have a minimum of 11% chromium and up to 9.8% carbon. It can also include a second alloy material, such as nickel, which is also used in many grades, or molybdenum.
The greatest benefit of stainless steel is its high resistance to corrosion, due to a spontaneous chromium oxide film that is created on the steel surface. Even though this is a very thin layer that is hardly perceptible, its adherence to the metal protects it against a wide range of corrosive agents thanks to its stability and impermeability.
It the chromium film constitutes 11% of the alloy, protection will suffice against a not very aggressive environment, such as inside a home. However, if the steel is outdoors, it is ultimately corroded. If the chromium content is increased to 18%, the steel will have greater resistance, even outdoors. That is do say, the degree of resistance of the oxide film does not depend only on the amount of chromium or the total composition of the alloy, but there are also other external factors to be taken into account, such as the grade of the corrosive medium, the temperature, and the level of aggressiveness in the environment.
Benefits of Stainless Steel
1. Corrosion resistance
The main feature of all types of stainless steel is their high degree of corrosion resistance. Low-alloy steel resists environmental corrosion well, while high-alloy steel resists more extreme corrosion, such as that of acids and high temperatures.
2. Resistance to high and low temperature
Some types of steel are prepared to withstand extreme thermal variations, and display great resistance to very high temperatures. Other types of steel, however, are characterised by their hardness in cryogenic temperatures.
3. Ease of fabrication
Most grades can be manipulated and handled with good results.
4. Mechanical strength
Stainless steel is heat-treated to create highly resistant components. Hardened steel is used in design to decrease thickness and costs.
5. Aesthetics and hygiene
Stainless steel is easy to clean and is found in many surface areas. For this reason, it is frequently used in catering, healthcare establishments, etc.