What is the composition of steel?

Steel is primarily composed of iron along with carbon, with the carbon content typically ranging from 0.02% to 2.11%. This specific composition allows steel to exhibit a balance of strength and ductility, making it suitable for a wide range of applications, including construction, automotive parts, and tools. The presence of carbon is crucial as it acts as a hardening agent, which enhances the strength and increases the tensile properties of the iron. The limit of 2.11% carbon is significant because exceeding this percentage would classify the material as cast iron instead of steel.

Other options do not accurately reflect the recognized composition of steel. For instance, the mix of iron with aluminum and carbon does not represent standard steel but rather an alloy type that isn't commonly identified as steel. Similarly, copper and iron alloys refer to bronze and other metal mixtures that fall outside the definition of steel. Finally, stating that steel consists of only iron with no carbon content misrepresents the fundamental nature of steel, which relies on carbon as an integral component for its definition and characteristics.