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Alloy Steels

Alloy steels play an important role in all fields of industry. They are produced by the introduction of certain non-ferrous metals into low-carbon steels, notably tungsten, manganese, nickel and chromium.

One of the earliest alloy steels was introduced by R.F.Mushet who by adding tungsten to steel discovered self-hardening steel in 1868. Tools made by this method revolutionized machining processes, and it was also upon Mushet's self-hardening steel that the experiments were based, which led to the production of the high-speed steels developed later in America.

In 1893 Robert Hadfield made an important step forward in this field by incorporating manganese in steel. This alloy was found to possess remarkable tensile strength, elongation and hardness, and became invaluable for all machinery and plant subject to abrasive action such as railway crossings, dredger buckets and the like. These types of steel, however, did not provide a steel suitable for general constructional purposes, a start in this direction being made by J.Riley of Glasgow, who in 1889 by small additions of nickel to steel markedly increased the strength and toughness without decreasing the ductility. By addition of a further alloying element, chromium, H. Brearley in 1913 founded a class of constructional steels which, in addition to strength and resistance to wear, were also resistant to corrosion.

These alloy steels heralded in the Alloy Steel Age, and so great was their development that at the outbreak of the 1939 war there were no less than 2,000 different specifications dealing solely with alloys having various proportions of nickel, chromium and small additions of other elements. With such developments as jet propulsion, nuclear fusion as a source of power and space technology, the acceleration in alloys is likely to continue.

 



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