Question

why steel has carbon in its structure? is there any simple explanation? it's for homework

Answer 1

Historically, the most simple and affordable technology was coke smelting of iron, and with some technological modifications, it is still used nowadays. so processed iron ore contains carbon due to technological process applied. moreover, it turned out that carbon adds strength to steel in contrast to pure iron which is rather soft (in fact, softer than allumunium). thus, historically present, carbon proved to be beneficial addon to steel. other chemicals (nearly all from table of elements) are used, yet carbon is applied most.