Mushet
NAME: Mushet, Robert Forester
ACHIEVEMENT(S): Machine tool steel
NICKNAME/ALIAS: None
DATE/PLACE OF BIRTH: 8 April 1811, at Coleford, Forest of Dean,
Gloucestershire, England
DATE/PLACE/AGE AT DEATH: 19 January 1891, in Cheltenham, Gloucestershire,
England. Aged 79
DISCIPLINE: Metallurgist and iron and steel maker
FIELD: Metallurgy
LANGUAGE: English
PARENTS: David Mushet (1772-1847) and Agnes Wilson, married 1798
SIBLINGS: Six elder siblings: Margaret (b. 1799), Hariot (b. 1801),
Henrietta (b. 1802), William (b. 1803), David (b. 1805), James (b. 1807) and
Agnes (b. 1809)
SPOUSE: Mary Ann Thomas (1819-1914), married 1841
CHILDREN: Edward Maxwell Tom (1842-1908), Henry Charles Brooklyn (1845-1923)
and Lisowna Mary (1850-75)
EDUCATION: National School, Coleford, 1816-21; Bell's Grammar School,
Newland, 1821-23
MAJOR WORK: 'The Bessemer-Mushet Process or Manufacture of Cheap Steel',
1883
LIFE AND TIMES: Mushet was the youngest child of David Mushet, the well-known metallurgist, coal-mine owner and iron and steel manufacturer.
In 1844, his father travelled to Edinburgh in order to give evidence in a case brought by <a pal of> Neilson*, the son of his old partner, against an iron works which was refusing to pay royalties for using Neilson’s hot blast method. Robert Mushet, now 34, with his two surviving brothers (George and David), was given the Darkhill Ironworks and two coal works nearby.
Mushet continued administering his father's many businesses 1847 when he went into partnership with a Birmingham merchant as R.Mushet & Co. and set up a "small, experimental steelworks" at Coleford.
The principle equipment consisted of a crucible furnace and a pair of wooden tilt hammers (an early form of mechanical hammer), and here Mushet - with about ten workmen - began to make cast steel based on the method his father had patented in 1800, in which iron ore was melted with charcoal and manganese oxide in clay crucibles and then poured into moulds to make steel ingots.
In the summer of 1848, a few months after the works had begun to operate, Mushet was visited by Henry Burgess, editor of the 'Bankers' Circular', who brought him a lump of white crystallised metal from a mountain in Prussia. Mushet immediately recognised the metal as an alloy of iron and manganese known as 'spiegeleisen,' from which the famous Prussian steel was produced. Mushet immediately ordered 12 tons, combined the metal with iron and steel, and discovered that a very small amount of spiegeleisen increased the steel’s hardness and elasticity.
For financial reasons, during the early 1850s Mushet did not invest in this discovery, but continued making cast steel by the old formula. Then, in 1856 <work related to> Bessemer* patented his process for mass-producing good quality steel cheaply by
removing the impurities from pig iron with a cold air blast. Bessemer claimed that this process (called the 'pneumatic process' because it uses only cold air) could produce good quality steel.
In August 1856 Mushet's friend Thomas Brown brought him a copy of Bessemer's paper read to the British Association two days earlier, as well as a piece of Bessemer steel. Mushet came to the conclusion that the steel was of poor quality, and that Bessemer's process did not remove all the impurities in the iron.
The solution, he decided, was to remove, as far as possible, all the impurities and all the carbon from the iron, and then reintroduce carbon and manganese in precisely the quantities needed.
He then carried out experiments based on those he had carried out on spiegeleisen eight years earlier, mixing spiegeleisen into molten iron purged of all impurities and carbon, and produced the first bar of perfect cast steel. He immediately began proceedings for a patent in Britain and France, which he received in late 1856, and another in the United States in 1857. Meanwhile, Brown, who was the managing partner of the Ebbw Vale Iron Co., in Wales, offered to erect a small Bessemer converter and there, in 1856 Mushet made the first steel rail, used by the Midland Railway Co.
However, Mushet failed either to talk to Bessemer (who was desperate to learn of Mushet's discovery) or pay him any royalties for the use of his process, and for this reason failed to make any money from his discovery. In 1859 by mistake the stamp duty on the patents were not paid, and Mushet immediately lost all patent rights and his invention became public property.
Mushet continued his business at his works, producing steel according to his father's process. Although short of money, he also continued his experiments (over 10,000
during the next 10 years), concentrating especially on steel alloys, mixing titanium (with which his father had experimented 60 years earlier), manganese, chromium and tungsten in turn and in combination with steel in order to improve its quality, and taking out 48 patents in 10 years.
One of his discoveries was a hard steel made from iron and titanium which he called Titanic cast steel, and in October 1862 the Titanic Steel & Iron Co. Ltd was launched and a huge new works was built. In 1868, after Mushet pulverized and melted a lump of pig iron cast from ore rich in manganese, and then added some finely powered metallic tungsten, Mushet produced a much harder type of steel and immediately began to use this (unpatented) process to produce the forerunner of all the special alloy steels made today.
For two years the process was a financial success, but by 1870 bad management caused the Titanic Steelworks to fail, and Mushet sold the business and retired.
ASSESSMENT: Revolutionized bridge and building construction.
EXTRA CONNECTIONS: None
ONELINER: Robert Mushet, alloy steel pioneer
BIBLIOGRAPHY:
Anstis, Ralph, Man of Iron - Man of Steel: The Lives of David and Robert Mushet, Coleford, Glos.: Albion House, 1997