A broad, shallow hearth to refine pig iron and scrap into steel. Heat is supplied from a large, luminous flame over the surface, and the refining takes seven to nine hours. The open-hearth process has been replaced by the basic oxygen process in most modern facilities.
A furnace for melting metal, in which the bath is heated by the convection of hot gases over the surface of the metal and by radiation from the roof.
A reverbatory melting furnace with a shallow hearth, on which the charge is placed beneath a low roof. Heating of the charge is both by direct flame and by radiation from the furnace roof and sidewalls. This type of furnace is no longer used in Western Europe as a steelmaking unit as it has now been replaced, for economic and quality reasons, by the Basic Oxygen and the Electric Arc Furnace Steelmaking processes.
Developed in the middle of the last century, the open hearth or Siemens-Martins process, as it is known, accounted for a major proportion of UK steel production until the early 1970's. For economic and quality reasons it has been replaced by the Electric Arc Furnace and the Basic Oxygen Steelmaking process. There are no open hearth furnaces in use in Britain today but they are still in use in Russia and Eastern Europe.
A furnace with a shallow hearth used in steel processing. The steel is directly exposed to the heat source.
Open hearth furnaces are one of a number of kinds of furnace where excess carbon and other impurities are burnt out of pig iron to produce steel. Since steel is difficult to manufacture due to its high melting point, normal fuels and furnaces were insufficient and the open hearth furnace was developed to overcome this difficulty. Most open hearth furnaces were closed by the early 1990s, not least because of their fuel inefficiency, being replaced by basic oxygen furnace or electric arc furnace.
