- Bessemer, Sir Henry
- SUBJECT AREA: Metallurgy[br]b. 19 January 1813 Charlton (near Hitchin), Hertfordshire, Englandd. 15 January 1898 Denmark Hill, London, England[br]English inventor of the Bessemer steelmaking process.[br]The most valuable part of Bessemer's education took place in the workshop of his inventor father. At the age of only 17 he went to London to seek his fortune and set himself up in the trade of casting art works in white metal. He went on to the embossing of metals and other materials and this led to his first major invention, whereby a date was incorporated in the die for embossing seals, thus preventing the wholesale forgeries that had previously been committed. For this, a grateful Government promised Bessemer a paid position, a promise that was never kept; recognition came only in 1879 with a belated knighthood. Bessemer turned to other inventions, mainly in metalworking, including a process for making bronze powder and gold paint. After he had overcome technical problems, the process became highly profitable, earning him a considerable income during the forty years it was in use.The Crimean War presented inventors such as Bessemer with a challenge when weaknesses in the iron used to make the cannon became apparent. In 1856, at his Baxter House premises in St Paneras, London, he tried fusing cast iron with steel. Noticing the effect of an air current on the molten mixture, he constructed a reaction vessel or converter in which air was blown through molten cast iron. There was a vigorous reaction which nearly burned the house down, and Bessemer found the iron to be almost completely decarburized, without the slag threads always present in wrought iron. Bessemer had in fact invented not only a new process but a new material, mild steel. His paper "On the manufacture of malleable iron and steel without fuel" at the British Association meeting in Cheltenham later that year created a stir. Bessemer was courted by ironmasters to license the process. However, success was short-lived, for they found that phosphorus in the original iron ore passed into the metal and rendered it useless. By chance, Bessemer had used in his trials pig-iron, derived from haematite, a phosphorus-free ore. Bessemer tried hard to overcome the problem, but lacking chemical knowledge he resigned himself to limiting his process to this kind of pig-iron. This limitation was removed in 1879 by Sidney Gilchrist Thomas, who substituted a chemically basic lining in the converter in place of the acid lining used by Bessemer. This reacted with the phosphorus to form a substance that could be tapped off with the slag, leaving the steel free from this harmful element. Even so, the new material had begun to be applied in engineering, especially for railways. The open-hearth process developed by Siemens and the Martin brothers complemented rather than competed with Bessemer steel. The widespread use of the two processes had a revolutionary effect on mechanical and structural engineering and earned Bessemer around £1 million in royalties before the patents expired.[br]Principal Honours and DistinctionsKnighted 1879. FRS 1879. Royal Society of Arts Albert Gold Medal 1872.Bibliography1905, Sir Henry Bessemer FRS: An Autobiography, London.LRD
Biographical history of technology. - Taylor & Francis e-Librar. Lance Day and Ian McNeil. 2005.
