Iron occurs on Earth in many forms, but is primarily extracted from the iron oxide ores of Magnetite, Haematite, Ochres, Siderite and also meteoric iron. Although one of the most abundant elements in nature, mans understanding of iron evolved slowly.
The Sumerians who lived on the Euphrates River in what is now Iraq, and the Hittites who inhabited the southern part Turkey were the first people known to use iron. Around 4000 BC Egyptians and Sumerians were fabricating small items from iron extracted from meteorites. Around 1000 BC the Hittites developed a process of heating iron, hammering it into shape then quickly cooling, resulting in a metal that although limited in size was harder than bronze.
The discovery that two pieces of iron could be fused using intense heat then hammering gave rise to wrought iron, the first true form of iron known to man. What ancient ironworkers did not understand is that reducing the carbon content of iron by repeated melting and hammering would produce a more malleable product.
The term Wrought Iron is widely misused, as it is routinely applied to products created from bent and cast metals and alloys, which ironically are the products and procedures that advanced the decline of the Blacksmiths art. The skill, labor, and time required to produce Wrought iron makes it considerably more expensive than the ornamental iron commonly found today. Since true wrought ironwork is forged by hand, small irregularities are usually apparent and valued as evidence of the smith’s craft.
Cast iron is exceptionally strong, taking its name from the fact that it is cast into moulds while in a molten state. Cast iron is however brittle, and once formed cannot be reshaped even with extreme heat applications.
Steel is iron with a precise amount of carbon that can be cast into moulds from the furnace or shaped when red-hot. Although the most useful of all iron products, steel was not readily produced because its manufacture requires exacting control over carbon content that the smelting furnace could not control.
Carbon is the key variable distinguishing wrought iron, steel, and cast iron. Low carbon content delivers wrought iron, while an abundance of carbon makes cast iron, however a precisely controlled carbon content of approximately 1% will result in steel.