Steel is an alloy of iron and carbon containing less than 2% carbon and 1% manganese and small amounts of silicon, phosphorus, Sulphur and oxygen. Steel is the world’s most important engineering and construction material. It is used in every aspect of our lives; in cars and construction products, refrigerators and washing machines, cargo ships and surgical scalpels.
Different types of steel
Steel is not a single product. There are more than 3,500 different grades of steel with many different physical, chemical, and environmental properties. During the production process, different types of steel are created and categorized by their physical, chemical, and environmental properties. These properties include the amount of carbon, the level of impurities, and the addition of other alloying elements.
Each type of steel allows for different uses and applications, and are broken down into four different groups by the chemical structures and physical properties:
Carbon steels contain trace amounts of alloying elements such as manganese, silicon, and copper. They are often dull and matte in appearance and account for 90% of total steel production. There are three sub-groups that categorize carbon steels based on their carbon content:
- Low Carbon Steel: contains less than .3% carbon and is the most common carbon steel.
- Medium Carbon Steel: contains between .3%-.6% carbon and often has manganese added.
- High Carbon Steel: contains 1.5% carbon and is the strongest of the carbon steels.
Alloy steels contain varying amounts of alloying elements (e.g., aluminum, chromium, copper, manganese, nickel, silicon, titanium). These additional elements change the steel’s properties. Some examples of these properties include corrosion resistance, strength, or ductility. These steels tend to be cheaper and are often used in auto parts, mechanical work, power generators, and pipelines.
Stainless steels have a low carbon content and typically contain between 10%-20% chromium. They are commonly found in home appliances, food processing equipment, and kitchen utensils because of their strength and resistance to both corrosion and high temperatures.
Tool steels contain varying amounts of cobalt, molybdenum, tungsten, and vanadium that make them extremely hard, durable, and heat resistant. These steels are ideal for making metal tools (hence their name) and are ideal for drilling, cutting, and stamping.
Steel is completely recyclable, possesses great durability, and, compared to other materials, requires relatively low amounts of energy to produce. Innovative lightweight steels (such as those used in in automobiles and buildings) help to save energy and resources. The steel industry has made immense efforts to limit environmental pollution in the last decades.
Producing one ton of steel today requires just 40% of the energy it did in 1960. Dust emissions have been reduced by even more.