Editing Steel (section)

===Modern===
[[File:Bessemer Converter Sheffield.jpg|thumb|upright|A [[Bessemer process|Bessemer converter]] in [[Sheffield]], England]]
Since the 17th century, the first step in European steel production has been the smelting of iron ore into [[pig iron]] in a [[blast furnace]].<ref name="Tylecote">{{cite book |last=Tylecote |first=R. F. |date=1992 |title=A History of Metallurgy |edition=2nd |publisher=Institute of Materials |location=London |pages=95–99, 102–105 |isbn=0-901462-88-8}}</ref>{{page needed|date=April 2024}} Originally employing charcoal, modern methods use [[coke (fuel)|coke]], which has proven more economical.<ref>{{cite book |last=Raistrick |first=A. |date=1953 |title=A Dynasty of Ironfounders}}</ref>{{page needed|date=April 2024}}<ref>{{cite book |last=Hyde |first=C. K. |date=1977 |title=Technological Change and the British Iron Industry |publisher=Princeton University Press}}</ref>{{page needed|date=April 2024}}<ref>{{cite book |last=Trinder |first=B. |date=2000 |title=The Industrial Revolution in Shropshire |edition=3rd |location=Chichester |publisher=Phillimore |isbn=9781860771330}}</ref>{{page needed|date=April 2024}}

====Processes starting from bar iron====
{{Main|Blister steel|Crucible steel}}
In these processes, [[pig iron]] made from raw iron ore was refined (fined) in a [[finery forge]] to produce [[bar iron]], which was then used in steel-making.<ref name="Tylecote" />

The production of steel by the [[cementation process]] was described in a treatise published in Prague in 1574 and was in use in [[Nuremberg]] from 1601. A similar process for [[case hardening]] armour and files was described in a book published in [[Naples]] in 1589. The process was introduced to England in about 1614 and used to produce such steel by Sir [[Basil Brooke (metallurgist)|Basil Brooke]] at [[Coalbrookdale]] during the 1610s.{{sfnp|Barraclough|1984a|pp=48–52}}

The raw material for this process were bars of iron. During the 17th century, it was realized that the best steel came from [[oregrounds iron]] of a region north of [[Stockholm]], Sweden. This was still the usual raw material source in the 19th century, almost as long as the process was used.<ref>{{cite journal |last=King |first=P. W. |title=The Cartel in Oregrounds Iron: trading in the raw material for steel during the eighteenth century |journal=Journal of Industrial History |volume=6 |issue=1 |date=2003 |pages=25–49}}</ref><ref name="britannicaironandsteel">{{cite book |chapter=Iron and steel industry |title=Encyclopædia Britannica |date=2007}}</ref>

Crucible steel is steel that has been melted in a [[crucible]] rather than having been [[forging|forged]], with the result that it is more homogeneous. Most previous furnaces could not reach high enough temperatures to melt the steel. The early modern crucible steel industry resulted from the invention of [[Benjamin Huntsman]] in the 1740s. Blister steel (made as above) was melted in a crucible or in a furnace, and cast (usually) into ingots.<ref name="britannicaironandsteel" />{{sfnp|Barraclough|1984b}}{{page needed|date=April 2024}}

====Processes starting from pig iron====
[[File:Siemens Martin Ofen Brandenburg.jpg|thumb|An [[open hearth furnace]] in the Museum of Industry in [[Brandenburg]], Germany]]
[[File:Allegheny Ludlum steel furnace.jpg|thumb|White-hot steel pouring out of an electric arc furnace in [[Brackenridge, Pennsylvania]]]]
The modern era in [[steelmaking]] began with the introduction of [[Henry Bessemer]]'s [[Bessemer process|process]] in 1855, the raw material for which was pig iron.<ref>{{cite book |title=History of the Manufacture of Iron in All Ages |last=Swank |first=James Moore |isbn=0-8337-3463-6 |date=1892 |publisher=Burt Franklin}}</ref> His method let him produce steel in large quantities cheaply, thus [[mild steel]] came to be used for most purposes for which wrought iron was formerly used.<ref>{{cite book |chapter=Bessemer process |chapter-url= https://www.britannica.com/technology/Bessemer-process |volume=2 |page=168 |title=[[Encyclopædia Britannica]] |edition=online |date=2005}}</ref> The Gilchrist-Thomas process (or ''basic Bessemer process'') was an improvement to the Bessemer process, made by lining the converter with a [[basic (chemistry)|basic]] material to remove phosphorus.

Another 19th-century steelmaking process was the [[Siemens-Martin process]], which complemented the Bessemer process.<ref name="britannicaironandsteel" /> It consisted of co-melting bar iron (or steel scrap) with pig iron.

These methods of steel production were rendered obsolete by the Linz-Donawitz process of [[basic oxygen steelmaking]] (BOS), developed in 1952,<ref name="zs">{{cite news |last1=Sherman |first1=Zander |title=How my great-grandfather's Dofasco steel empire rose and fell, and his descendants with it |url= https://www.theglobeandmail.com/business/rob-magazine/article-how-my-great-grandfathers-dofasco-steel-empire-rose-and-fell-and-his/ |work=[[The Globe and Mail]] |date=4 September 2019}}</ref> and other oxygen steel making methods. Basic oxygen steelmaking is superior to previous steelmaking methods because the oxygen pumped into the furnace limited impurities, primarily nitrogen, that previously had entered from the air used,<ref>{{cite book |chapter=Basic oxygen process |title=[[Encyclopædia Britannica]] |date=2007}}</ref> and because, with respect to the open hearth process, the same quantity of steel from a BOS process is manufactured in one-twelfth the time.<ref name="zs" /> Today, [[electric arc furnace]]s (EAF) are a common method of reprocessing [[scrap|scrap metal]] to create new steel. They can also be used for converting pig iron to steel, but they use a lot of electrical energy (about 440 kWh per&nbsp;metric ton), and are thus generally only economical when there is a plentiful supply of cheap electricity.{{sfnp|Fruehan|Wakelin|1998|pp=48–52}}