Steel is primarily made up of iron and carbon, with the carbon content typically ranging between about 0.02% and 2.14% by weight. The presence of carbon makes steel harder and stronger than pure iron. In addition to iron and carbon, steel often contains other alloying elements such as manganese, chromium, nickel, molybdenum, vanadium, titanium, boron, and copper. These elements are added intentionally to modify properties like hardness, corrosion resistance, strength, toughness, and weldability. Small amounts of other elements like phosphorus, sulfur, silicon, oxygen, and nitrogen may also be present, some of which may be considered impurities or have specific effects on the steel’s performance. Overall, steel is an alloy primarily of iron and carbon with various other elements added depending on the steel grade and its intended use.