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Last edited 27 Nov 2020
Pure iron (sometimes referred to as ferrite) is relatively soft but it is significantly hardened and strengthened during the smelting process by impurities such as carbon. Pig iron, with a high carbon content (3.8-4.7%) is produced in a blast furnace by heating iron ore with limestone and coke. Steel is produced by further refining pig iron with oxygen, reducing the carbon content to 0.04-1.5%. Steel can be up to 1,000 times harder than pure iron. Carbon steel is typically classified as low, medium, or high carbon steel.
Wrought iron is a very low carbon metal, historically made by intensive hand work using small scale production methods. Confusingly, the term 'wrought iron' can also be applied to decorative hand made steel artefacts as 'wrought' means to make by hand (to wrought).
The term 'cast iron' refers to a range of iron-carbon alloys, with a carbon content that is typically between 2 and 4%. During the Industrial Revolution, before the widespread development of the steel industry, cast iron was commonly used in a wide range of architectural applications because of to its relative affordability.
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