or Siemens-Martin process
Steelmaking technique that for most of the 20th century accounted for most steel made in the world.
William Siemens made steel from pig iron in a reverberatory furnace of his design in 1867. The same year the French manufacturer Pierre-Émile Martin (18241915) used the idea to produce steel by melting wrought iron with steel scrap. Siemens used the waste heat given off by the furnace: he directed the fumes from the furnace through a brick checkerwork, heating it to a high temperature, and then used the same path to introduce air into the furnace; the preheated air significantly increased the flame temperature. The open-hearth process furnace (which replaced the Bessemer process ) has itself been replaced in most industrialized countries by the basic oxygen process and the electric furnace . See also reverberatory furnace .