Robert Forester Mushet (8 April 1811 – 29 January 1891) was a British

metallurgist Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the sc ...

and businessman, born on 8 April 1811, in Coleford, in the

Forest of Dean The Forest of Dean is a geographical, historical and cultural region in the western part of the county of Gloucestershire, England. It forms a roughly triangular plateau bounded by the River Wye to the west and northwest, Herefordshire to ...

, Gloucestershire, England. He was the youngest son of Scottish parents, Agnes Wilson and David Mushet; an

ironmaster An ironmaster is the manager, and usually owner, of a forge or blast furnace for the processing of iron. It is a term mainly associated with the period of the Industrial Revolution, especially in Great Britain. The ironmaster was usually a large ...

, formerly of the Clyde, Alfreton and

Whitecliff Ironworks Whitecliff Ironworks, sometimes referred to as Whitecliff Furnace, at Coleford, in the Forest of Dean, Gloucestershire, England, are industrial remains associated with the production of iron, using coke, in the Forest of Dean. Background The f ...

. In 1818/9 David Mushet built a foundry named

Darkhill Ironworks Darkhill Ironworks, and the neighbouring Titanic Steelworks, are internationally important industrial remains associated with the development of the iron and steel industries. Both are scheduled monuments. They are located on the edge of a small ...

in the

. Robert spent his formative years studying metallurgy with his father and took over the management of Darkhill in 1845. Anstis p. 85. In 1848 he moved to the newly constructed Forest Steel Works on the edge of the Darkhill site where he carried out over ten thousand experiments in ten years Anstis p. 157 before moving to the Titanic Steelworks in 1862. It seems that Mushet only began using his middle name 'Forester' in 1845, and only occasionally at first. In his later years he said he had been given the name from the Forest of Dean, although he variously spelled it both 'Forester' and 'Forrester'. Anstis pp. 175–176. In 1876 he was awarded the Bessemer Gold Medal by the

Iron and Steel Institute The Iron and Steel Institute was an English association organized by the iron trade of the north of England. Its object was the discussion of practical and scientific questions connected with the manufacture of iron and steel. History The first mee ...

, their highest award.

Webb Webb most often refers to James Webb Space Telescope which is named after James E. Webb, second Administrator of NASA. It may also refer to: Places Antarctica * Webb Glacier (South Georgia) * Webb Glacier (Victoria Land) * Webb Névé, Victor ...

p. 14. Robert Mushet died on 29 January 1891 in

Cheltenham Cheltenham (), also known as Cheltenham Spa, is a spa town and borough on the edge of the Cotswolds in the county of Gloucestershire, England. Cheltenham became known as a health and holiday spa town resort, following the discovery of mineral s ...

. He is buried with his wife and daughter, Mary, in Cheltenham Cemetery.

High quality steel

In the summer of 1848, Henry Burgess, editor of ''The Bankers' Circular'', brought to Mushet a lump of white crystallised metal which he said was found in

Rhenish The Rhineland (german: Rheinland; french: Rhénanie; nl, Rijnland; ksh, Rhingland; Latinised name: ''Rhenania'') is a loosely defined area of Western Germany along the Rhine, chiefly its middle section. Term Historically, the Rhinelands ...

Prussia Prussia, , Old Prussian: ''Prūsa'' or ''Prūsija'' was a German state on the southeast coast of the Baltic Sea. It formed the German Empire under Prussian rule when it united the German states in 1871. It was ''de facto'' dissolved by an e ...

''... "Being familiar with alloys of iron and manganese," says Mr. Mushet, "I at once recognized this lump of metal as an alloy of these two metals and, as such, of great value in the making of steel. Later, I found that the white metallic alloy was the product of steel ore, called also spathose iron ore, being, in fact, a double carbonate of iron and manganese found in the Rhenish mountains, and that it was most carefully selected and smelted in small blast furnaces, charcoal fuel alone being employed and the only flux used being lime. The metal was run from the furnace into shallow iron troughs similar to the old refiners' boxes, and the cakes thus formed, when cold and broken up, showed large and beautifully bright facets and crystals specked with minute spots of uncombined carbon. It was called, from its brightness, 'spiegel glanz' or spiegel eisen, i.e., looking-glass iron. Practically its analysis was: Iron, 86…25; manganese, 8…50; and carbon, 5…25; making a total of 100…00."''

Mushet carried out many experiments with the metal, discovering that a small amount added during the manufacture of steel rendered it more workable when heated. It was not until 1856, however, that he realised the true potential of this property when his friend Thomas Brown brought him a piece of steel, made using the

Bessemer Process The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is removal of impurities from the iron by oxidation ...

, asking if he could improve its poor quality. Mushet carried out experiments on the sample, based on those he had previously carried out with spiegeleisen.

Henry Bessemer Sir Henry Bessemer (19 January 1813 – 15 March 1898) was an English inventor, whose steel-making process would become the most important technique for making steel in the nineteenth century for almost one hundred years from 1856 to 1950. He ...

himself had realised that the problem of quality was due to impurities in the iron and concluded that the solution lay in knowing when to turn off the flow of air in his process; so that the impurities had been burned off, but just the right quantity of carbon remained. Despite spending tens of thousands of pounds on experiments, however, he could not find the answer. Anstis p. 147. Mushet's solution was simple, but elegant; he first burnt off, as far as possible, ''all'' the impurities and carbon, then reintroduced carbon and manganese by adding an exact amount of spiegeleisen. This had the effect of improving the quality of the finished product, increasing its malleability – its ability to withstand rolling and forging at high temperatures. Anstis p. 140.

''I saw then that the Bessemer process was perfected and that, with fair play, untold wealth would reward Mr. Bessemer and myself..."''

Mushet's dream was never to be fulfilled. While others made fortunes from his discoveries, he failed to capitalise on his successes and by 1866 was destitute and in ill health. In that year his 16-year-old daughter, Mary, travelled to London alone, to confront Bessemer at his offices, arguing that his success was based on the results of her father's work.''Sir Henry Bessemer, F.R.S. An Autobiography'', Bessemer, whose own process for producing steel was not economically viable without Mushet's method for improving quality, decided to pay Mushet an annual pension of £300, a very considerable sum, which he paid for over 20 years; possibly with a view to keeping the Mushets from legal action.

Steel rails

In 1857 Mushet was the first to make durable rails of steel rather than cast iron, providing the basis for the development of rail transportation throughout the world in the late nineteenth century. The first of Mushet's steel rails was sent to Derby Midland railway station, where it was laid down at a particularly heavily used part of the station approach where the iron rails had to be renewed at least every six months, and occasionally every three. Six years later, in 1863, the rail seemed as perfect as ever, although some 700 trains had passed over it daily. During its 16 years "life" 1,252,000 detached engines and tenders at the least, apart from trains, had passed over that rail.

Dozzles

When steel solidifies in a mould, uneven cooling causes a central cavity or 'pipe' to form in the casting. In 1861 Mushet invented the 'Dozzle'; a clay cone or sleeve, heated white hot and inserted into the top of the ingot mould near the end of the pour, and then filled with molten steel. Its purpose was to maintain a reservoir of molten steel, which drained down and filled the pipe as the casting cooled. Mushet claimed this, and other small inventions of his, saved the steelmakers of Sheffield 'many millions of pounds' (in 19th century money), yet he received neither payment nor recognition for these inventions.

p. 15. Dozzles, now called hot tops or feeder heads, are still in use today.

Steel alloys

In a second key advance in metallurgy Mushet invented 'R Mushet's Special Steel' (RMS) in 1868.''Sheffield Steel and America: A Century of Commercial and Technological Independence'' By Geoffrey Tweedale -- Cambridge University Press 1987 Page 66--68 It was both the first true

tool steel Tool steel is any of various carbon steels and alloy steels that are particularly well-suited to be made into tools and tooling, including cutting tools, dies, hand tools, knives, and others. Their suitability comes from their distinctive har ...

and the first air-hardening steel., Previously, the only way to make steel hard enough for machine tools had been to quench it, by rapid cooling in water. With self-hardening (or tungsten) steel,

machine tools A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. Al ...

could run much faster and were able to cut harder metals than had been possible previously. RMS revolutionised the design of machine tools and the progress of industrial metalworking, and was the forerunner of high speed steel.

References

Bibliography

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