A huge range of items can be made from steel, from tiny paperclips to huge girders forming the frames for skyscrapers. One useful property of steel is that it can be recycled and used over and over again.
Steel has a long history. People in India and Sri Lanka were making small amounts of steel more than 2,500 years ago. It was very expensive and was often used to make swords and knives. In the middle Ages, steel could be made only in small amounts since the processes took a long time.
In the time since, there have been many changes to the way steel is made. In about the year 1610 steel started to be made in England, and the way it was made got better and cheaper over the next 100 years. Cheap steel helped start the Industrial Revolution in England and in Europe. The first industrial Converter (metallurgy) for making cheap steel was the Bessemer converter, followed by Siemens-Martin open-hearth process.
Today the most common way of making steel is the basic-oxygen process. The converter is a large turnip-shaped vessel. Liquid raw iron called “pig iron” is poured in and some scrap metal is added in to balance the heat. Oxygen is then blown into the iron. The oxygen burns off the extra carbon and other impurities. Then enough carbon is added to make the carbon contents as wanted. The liquid steel is then poured. It can be either cast into molds or rolled into sheets, slabs, beams and other so-called “long products”, such as railway tracks. Some special steels are made in electric arc furnaces.
Steel is most often made by machines in huge buildings called steel mills. It is a very cheap metal and is used to make many things. Steel is used in making buildings and bridges, and all kinds of machines. Almost all ships and cars are today made from steel. When a steel object is old, or it is broken beyond repair, it is called scrap. It can be melted down and re-shaped into a new object. Steel is recyclable material; that is, the same steel can be used and re-used.
Alloys of steel, in which steel is combined with other metals, can be very useful. Railway tracks are often made of an alloy of steel and manganese.
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