open-hearthadj.
/ˌəʊp(ə)nˈhɑːθ/, U.S. /ˈoʊp(ə)nˈhɑrθ/ Metallurgy.
Relating to or designating a steel-making process (now largely disused) in which scrap iron or steel, limestone, and pig iron are melted together in a shallow reverberatory furnace, the mixture being heated by overhead gas burners which oxidize impurities in the iron. Cf. Siemens n. 1b.The furnace was invented by C. W. Siemens in 1864 and steel production using a mixture of scrap iron and pig iron was developed by P. B. E. Martin the same year. Waste gases leaving the furnace give up much of their heat to the incoming gas and air in a heat regenerator, and so increase the flame temperature achievable.
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society > occupation and work > equipment > furnace or kiln > furnace > parts of furnace > [noun] > hearth or floor of furnace
hearth1551
sole1615
laboratory1790
hearth bottom1821
mouth plate1852
open-hearth1870
shelf1879
kitchen1881
1870 Manufacturer & Builder Oct. 302/1 The furnaces employed are always reverberatories, either open-hearth or muffle-furnaces.
1897 Times 18 Oct. 12/1 To-day the open hearth system has completely asserted its supremacy.
1938 J. Newton Introd. Metall. xvi. 499 Ingot iron is commercially pure iron, with total impurities < 0·10 per cent, which is made by a special basic open-hearth process.
1946 Firth Brown Gloss. Metall. Terms 11 In the hot-metal process, iron from the blast furnace goes through the mixer to the open hearth furnace, and constitutes 75% or more of the charge.
1972 Guardian 21 June 14/5 The open hearth furnace, on which so much of Britain's former prosperity was based, is dead.
1992 N.Y. Rev. Bks. 22 Oct. 26/1 Carnegie had added the latest in open-hearth technology, built new finishing mills..and pushed overall production to unprecedented levels.
This entry has been updated (OED Third Edition, June 2004; most recently modified version published online March 2022).
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adj.1870