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Open-hearth steelmaking had superseded the Bessemer process in UK by 1900, but elsewhere in Europe, especially in Germany, the Bessemer and Thomas processes were used until the late 1960s when they were superseded by basic oxygen steelmaking. The last open-hearth furnace in former East Germany was stopped in 1993. In the US, steel production ...
Steelmaking is the process of producing steel from iron ore and/or scrap. Steel has been made for millennia, and was commercialized on a massive scale in the 1850s and 1860s, using the Bessemer and Siemens-Martin processes. Two major commercial processes are used.
Siemens-Martin open hearth furnace. The process of refining steel in a hearth, as developed by Pierre-Émile Martin, consists of smelting a mixture of cast iron and scrap or ore, then refining it by decarburization, desulfurization and dephosphorization. This method makes it possible to produce fine and alloy steels by adding noble elements.
In the 20th century, the US industry successively adopted the open hearth furnace, then the basic oxygen steelmaking process. Since the American industry peaked in the 1940s and 1950s, the US industry has shifted to small mini-mills and specialty mills, using iron and steel scrap as feedstock, rather than iron ore.
The Bessemer process was the first inexpensive industrial process for the mass production of steel from molten pig iron before the development of the open hearth furnace. The key principle is removal of impurities from the iron by oxidation with air being blown through the molten iron. The oxidation also raises the temperature of the iron mass ...
The hearth's shape is usually elliptical; 1.5–1.8 m (4.9–5.9 ft) in length and 1–1.2 m (3.3–3.9 ft) wide. If the furnace is designed to puddle white iron then the hearth depth is never more than 50 cm (20 in). If the furnace is designed to boil gray iron then the average hearth depth is 50–75 cm (20–30 in).
Integrated steel mill in the Netherlands.The two large towers are blast furnaces.. A steel mill or steelworks is an industrial plant for the manufacture of steel.It may be an integrated steel works carrying out all steps of steelmaking from smelting iron ore to rolled product, but may also be a plant where steel semi-finished casting products are made from molten pig iron or from scrap.
U.S. Steel and Bethlehem Steel introduced the oxygen process in 1964. [3] By 1970, half of the world's and 80% of Japan's steel output was produced in oxygen converters. [3] In the last quarter of the 20th century, use of basic oxygen converters for steel production was gradually, partially replaced by the electric arc furnace using scrap steel ...