Steel is primarily made of iron and carbon, with carbon content typically less than 2%. Iron is the main base metal, and carbon acts as the principal hardening agent that improves steel's strength and fracture resistance compared to pure iron
. Besides iron and carbon, steel often contains small amounts of other elements such as manganese, silicon, phosphorus, sulfur, and oxygen. These elements affect various properties of steel. For example, manganese increases hardness and stabilizes the structure, while chromium (commonly around 18% in stainless steel) enhances corrosion resistance and oxidation resistance
. Other alloying elements that may be added in varying amounts to produce different steel grades include nickel, molybdenum, vanadium, titanium, boron, cobalt, and copper. These elements tailor the steel's properties for specific applications, such as improving toughness, hardness, corrosion resistance, or heat treatment response
. In summary, steel is an alloy mainly composed of:
- Iron (the base metal)
- Carbon (less than 2%)
- Small amounts of manganese, silicon, phosphorus, sulfur, oxygen
- Alloying elements such as chromium, nickel, molybdenum, vanadium, and others depending on the steel type
This composition gives steel its characteristic strength, malleability, and versatility, making it one of the most widely used engineering materials worldwide.
