Question

Steel is an alloy made of iron and carbon combined in different proportions .why do you need an alloy of iron

Answer 1

People make and use alloys because metals don't have exactly the right properties for a particular job. Iron is a great building material but steel (an alloy made by adding small amounts of nonmetallic carbon to iron) is stronger, harder, and rustproof.
Alloy steels. As well as iron and carbon, alloy steels contain one or more other elements, such as chromium, copper, manganese, nickel, silicon, or vanadium. ... Alloy steels are generally stronger, harder, tougher, and more durable than carbon steels.