Pure metals themselves are often not satisfactory for many practical applications. For example, pure gold is too soft for most uses and is combined with other metals to form harder, more resistant mixtures. Mixtures that contain two or more metals are known as alloys. Perhaps the best known and most widely used of all alloys is steel.
The term steel refers to a number of different substances that contain iron as their major component along with one or more other elements. Stainless steel, as an example, contains about 18% chromium, 10% nickel, and small amounts of manganese, carbon, phosphorus, sulfur, and silicon, along with iron. When niobium is added to a steel alloy, the final product has unusually great strength. The addition of cobalt produces a form of steel that withstands the high temperatures of jet engines and gas turbines, and silicon steels are used in making electrical equipment.
In the final stages of metal production, the finished product is formed into some shape that can be used in other industries to make final products. Thus, steel can be purchased in the form of flat sheets, rings, wire rope and thread, slabs, cylinders, and other shapes.
See also Metallurgy.
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David E. Newton