The pure metal is not often encountered in commerce, but is usnally alloyed with carbon or other metals. The pure metal is very reactive chemically, and rapidly corrodes especially in moist air or at elevated temperatures. The relations of these forms are peculiar. It is hard, brittle, fairly fusible, and is used to produce other alloys, including steel. Carbon steel,is an alloy of iron with carbon, with small ampunts of Mn, 'S, P, and Si.
Alloy steels are carbori steels with other additives, such as nickel, chromium, vanadium, etc.
Iron is the cheapest and most abundant, useful, and important of all metals.