Editing Basic oxygen steelmaking (section)

==History==
The basic oxygen process developed outside of the traditional "big steel" environment. It was developed and refined by a single man, Swiss engineer [[Robert Durrer]], and commercialized by two small steel companies in [[allied-occupied Austria]], which had not yet recovered from the destruction of [[World War II]].<ref name=S97>Smil, p. 97.</ref>

In 1856, [[Henry Bessemer]] had patented a steelmaking process involving oxygen blowing for decarbonizing molten iron (UK Patent No. 2207).  For nearly 100 years commercial quantities of oxygen were not available or were too expensive, and steelmaking used air blowing. During WWII German (Karl Valerian Schwarz), Belgian ([[John Miles Steel|John Miles]]) and Swiss ([[Robert Durrer]] and [[Heinrich Heilbrugge]]) engineers proposed their versions of oxygen-blown steelmaking, but only Durrer and Heilbrugge brought it to mass-scale production.<ref name=S97/>

In 1943, Durrer, formerly a professor at the [[Technische Hochschule]] in Charlottenburg (now [[Technische Universität Berlin]]), returned to [[Switzerland]] and accepted a seat on the board of [[Roll AG]], the country's largest steel mill. In 1947 he purchased the first small 2.5-ton experimental converter from the US, and on April 3, 1948 the new converter produced its first steel.<ref name=S97/> The new process could conveniently process large amounts of [[scrap metal]] with only a small proportion of primary metal necessary.<ref name=S978/> In the summer of 1948, Roll AG and two Austrian state-owned companies, VÖEST and ÖAMG, agreed to commercialize the Durrer process.<ref name=S978>Smil, pp. 97–98.</ref>

By June 1949, VÖEST developed an adaptation of Durrer's process, known as the LD (Linz-Donawitz) process.<ref name=T313>Tweraser, p. 313.</ref><ref name=S98>Smil, p. 98.</ref> In December 1949, VÖEST and ÖAMG committed to building their first 30-ton oxygen converters.<ref name=S98/> They were put into operation in November 1952 (VÖEST in Linz) and May 1953 (ÖAMG, Donawitz)<ref name=S98/> and temporarily became the leading edge of the world's steelmaking, causing a surge in steel-related research.<ref name=B39>Brock and Elzinga, p. 39.</ref> Thirty-four thousand businesspeople and engineers visited the VÖEST converter by 1963.<ref name=B39/> The LD process reduced processing time and capital costs per ton of steel, contributing to the [[competitive advantage]] of Austrian steel.<ref name=T313/> VÖEST eventually acquired the rights to market the new technology.<ref name=S98/> Errors by the VÖEST and the ÖAMG management in licensing their technology made control over its adoption in [[Japan]] impossible. By the end of the 1950s, the Austrians lost their competitive edge.<ref name=T313/>

In the original LD process, oxygen was blown over the top of the molten iron through the water-cooled nozzle of a vertical lance. In the 1960s, steelmakers introduced bottom-blown converters and developed [[inert gas]] blowing for stirring the molten metal and removing [[phosphorus]] impurities.<ref name=S99/>

In the Soviet Union, some experimental production of steel using the process was done in 1934, but industrial use was hampered by lack of efficient technology to produce liquid oxygen. In 1939, the [[Russians|Russian]] physicist [[Pyotr Kapitsa]] perfected the design of the centrifugal [[turboexpander]]. The process was put to use in 1942–1944. Most turboexpanders in industrial use since then have been based on Kapitsa's design and centrifugal turboexpanders have taken over almost 100% of industrial gas liquefaction, and in particular the production of liquid oxygen for steelmaking.<ref name=Almqvist>{{cite book|author=Ebbe Almqvist|title=History of Industrial Gases|edition=First|publisher=Springer|year=2002|isbn=0-306-47277-5|page=[https://archive.org/details/historyofindustr00almq/page/165 165]|url-access=registration|url=https://archive.org/details/historyofindustr00almq/page/165}}</ref>

Big American steelmakers were late adopters of the new technology. The first oxygen converters in the US were launched at the end of 1954 by [[McLouth Steel]] in [[Trenton, Michigan]], which accounted for less than 1% of the national steel market.<ref name=S99/> [[U.S. Steel]] and [[Bethlehem Steel]] introduced the oxygen process in 1964.<ref name=S99/> By 1970, half of the world's and 80% of Japan's steel output was produced in oxygen converters.<ref name=S99/> 

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 and iron. In Japan the share of LD process decreased from 80% in 1970 to 70% in 2000; worldwide share of the basic oxygen process stabilized at 60%.<ref name=S99/>