Robert Forester Mushet
Encyclopedia
Robert Forester Mushet was a British
metallurgist
and businessman, born April 8, 1811, in Coleford
, in the Forest of Dean
, Gloucestershire
, England
. He was the youngest son of Scottish parents, Agnes Wilson and David Mushet
; an ironmaster
, formerly of the Clyde, Alfreton and Whitecliff Ironworks
.
In 1818/9 David Mushet built a foundry at Darkhill
, in the Forest of Dean
. Robert spent his formative years studying metallurgy with his father and took over the management of Darkhill in 1845. 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 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'.
In 1876 he was awarded the Bessemer Gold Medal by the Iron and Steel Institute, their highest award.
Robert Mushet died on January 29, 1891 in Cheltenham
. He is buried with his wife and daughter, Mary, in Cheltenham Cemetery.
The remains of Darkhill are now preserved as an Industrial Archaeological Site of International Importance and are open to the public.
.
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
, 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
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.
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.
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.
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.
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 delivered to Derby Midland railway station
, where "it was ... laid down early in 1857 at a heavily trafficked part of the line where the iron rails had to be renewed 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.
(RMS) in 1868. It was both the first true tool steel
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. Self-hardening (or tungsten) steel machine tools 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
.
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
metallurgist
Metallurgy
Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use...
and businessman, born April 8, 1811, in Coleford
Coleford, Gloucestershire
Coleford is a small market town in Gloucestershire, England in the west of the Forest of Dean with a population of 8,351 . It is situated some four miles east of the Welsh border, and is close to the Wye Valley, a popular walking and canoeing area...
, in the Forest of Dean
Forest of Dean
The Forest of Dean is a geographical, historical and cultural region in the western part of the county of Gloucestershire, England. The forest is a roughly triangular plateau bounded by the River Wye to the west and north, the River Severn to the south, and the City of Gloucester to the east.The...
, Gloucestershire
Gloucestershire
Gloucestershire is a county in South West England. The county comprises part of the Cotswold Hills, part of the flat fertile valley of the River Severn, and the entire Forest of Dean....
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. He was the youngest son of Scottish parents, Agnes Wilson and David Mushet
David Mushet
David Mushet was a Scottish metallurgist and the youngest son of Margaret Cochran and William Mushet.-Early life:Mushet was born on October 2, 1772, in Dalkeith, near Edinburgh. He was educated at Dalkeith Grammar School....
; an ironmaster
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....
, formerly of the Clyde, Alfreton and Whitecliff Ironworks
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:...
.
In 1818/9 David Mushet built a foundry at Darkhill
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 hamlet called Gorsty Knoll, just to the west of...
, in the Forest of Dean
Forest of Dean
The Forest of Dean is a geographical, historical and cultural region in the western part of the county of Gloucestershire, England. The forest is a roughly triangular plateau bounded by the River Wye to the west and north, the River Severn to the south, and the City of Gloucester to the east.The...
. Robert spent his formative years studying metallurgy with his father and took over the management of Darkhill in 1845. 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 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'.
In 1876 he was awarded the Bessemer Gold Medal by the Iron and Steel Institute, their highest award.
Robert Mushet died on January 29, 1891 in Cheltenham
Cheltenham
Cheltenham , also known as Cheltenham Spa, is a large spa town and borough in Gloucestershire, on the edge of the Cotswolds in the South-West region of England. It is the home of the flagship race of British steeplechase horse racing, the Gold Cup, the main event of the Cheltenham Festival held...
. He is buried with his wife and daughter, Mary, in Cheltenham Cemetery.
The remains of Darkhill are now preserved as an Industrial Archaeological Site of International Importance and are open to the public.
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, PrussiaPrussia
Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...
.
... "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 eisenSpiegeleisenSpiegeleisen is a ferromanganese alloy containing approximately 15% manganese and small quantities of carbon and silicon. Historically, this was the standard form in which manganese was traded and used in steel making...
, 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
Bessemer process
The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron. The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855. The process was independently discovered in 1851 by William Kelly...
, 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
Henry Bessemer
Sir Henry Bessemer was an English engineer, inventor, and businessman. Bessemer's name is chiefly known in connection with the Bessemer process for the manufacture of steel.-Anthony Bessemer:...
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.
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.
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.
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 railsRail profile
The rail profile is the cross sectional shape of a railway rail, perpendicular to the length of the rail.In all but very early cast iron rails, a rail is hot rolled steel of a specific cross sectional profile designed for use as the fundamental component of railway track.Unlike some other uses of...
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 delivered to Derby Midland railway station
Derby Midland railway station
Derby railway station , also known as Derby Midland Station, is a main line railway station serving the city of Derby in England. Owned by Network Rail and managed by East Midlands Trains, the station is also used by CrossCountry services and one Northern Rail service...
, where "it was ... laid down early in 1857 at a heavily trafficked part of the line where the iron rails had to be renewed 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. 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'Mushet steel
Mushet steel, also known as Robert Mushet's Special Steel , self-hardening steel and air-hardening steel, is considered the first tool steel and air-hardening steel. It was invented in 1868 by Robert Forester Mushet. Prior to Mushet steel, steel had to be quenched to harden it...
(RMS) in 1868. It was both the first true tool steel
Tool steel
Tool steel refers to a variety of carbon and alloy steels that are particularly well-suited to be made into tools. Their suitability comes from their distinctive hardness, resistance to abrasion, their ability to hold a cutting edge, and/or their resistance to deformation at elevated temperatures...
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. Self-hardening (or tungsten) steel machine tools 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
High speed steel
High speed steelMost copyeditors today would tend to choose to style the unit adjective high-speed with a hyphen, rendering the full term as high-speed steel, and this styling is not uncommon . However, it is true that in the metalworking industries the styling high speed steel is long-established...
.
Further reading
- Fred M. Osborn, The Story of the Mushets, London, Thomas Nelson & Sons (1952)