Final answer:
Steel is made from iron by removing impurities and adding substances to produce alloys with specific properties. Most steels contain small percentages of carbon, but excess carbon must be removed to prevent brittleness.
Step-by-step explanation:
Steel is made from iron by removing impurities and adding substances such as manganese, chromium, nickel, tungsten, molybdenum, and vanadium to produce alloys with specific properties. Most steels also contain small percentages of carbon. However, a large part of the carbon contained in iron must be removed in the manufacture of steel to prevent brittleness.