Steel is an alloy of iron with other metals. It has between
0.07 and 1.7 per cent carbon—wrought iron is practically free of carbon and cast iron has 4 per cent or more. As a result, steel can be made by adding carbon to wrought iron or removing it from cast iron. Steel is much less brittle than cast iron, and is stronger and easier to work. It is also relatively easily recycled.
The best-known steel-making method is the Bessemer converter process patented by Henry Bessemer in 1856, but steel has been produced for weapons and tools for centuries by the double shear process. Bessemer blast furnaces went out of use in most countries in the 1970s. The Siemens open-hearth furnace largely replaced Bessemer, and Siemens furnaces continue to be ...