Bessemer process, process of making steel from pig iron. The pig iron is loaded into a specially designed furnace or Bessemer converter. A continuous blast of compressed air is forced through the molten metal to oxidize impurities, which are burned off or form slag. The result is molten steel. Since the 1950s, a modification of the Bessemer process, the basic oxygen process, has been in use. The Bessemer process was developed by the British inventor Sir Henry Bessemer (1813–98).
See also: Steel.