Iron is the most common element in the world. It makes up 35% of the Earth, but most of it is in the Earth’s core.
Iron is never found in its pure form in the Earth’s crust. Instead it is found in iron ores, which must be heated in a blast furnace to extract the iron.
The chemical symbol for iron is Fe from ferrum, the Latin word for iron. Iron compounds are called either ferrous or ferric.
Iron has an atomic number of 26 and an atomic weight of 55.85.
Iron melts at 1535°C and boils at 3000°C. It conducts heat and electricity quite well and dissolves in water very slowly. Iron is easily magnetized. It also loses its magnetism easily, but steel can be permanently magnetic.
Iron combines readily with oxygen to form iron oxide, especially in the presence of moisture. This is rusting. Pouring molten iron into a steelmaking furnace in a steel mill. The temperature of the liquid metal is about 1500°C. A solid-state laser can cut through carbon steel like butter even though steel is incredibly tough.
Cast iron is iron with 2 to 4% carbon and 1 to 3% silicon. It is suitable for pouring into sand moulds. Wrought iron is almost pure iron with carbon removed to make it easy to bend and shape for railings and gates.
Iron is made into steel by adding traces of carbon for making cars, railway lines, knives and much more. Alloy steels are made by adding traces (for tools) and chromium (for ball bearings).
60% of steel is made by the basic oxygen process in which oxygen is blasted over molten iron to burn out impurities.
Special alloy steels such as chromium steels can be made from scrap iron (which is low in impurities) in an electric arc furnace.