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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.

History

Since the invention of the Bessemer process, steel mills have replaced ironworks, based on puddling or fining methods. New ways to produce steel appeared later: from scrap melted in an electric arc furnace and, more recently, from direct reduced iron processes.

In the late 19th and early 20th centuries the world's largest steel mill was the Barrow Hematite Steel Company steelworks located in Barrow-in-Furness, United Kingdom. Today, the world's largest steel mill is in Gwangyang, South Korea.^[1]^[2]

Integrated mill

Blast furnaces of Třinec Iron and Steel Works

An integrated steel mill has all the functions for primary steel production:

iron making (conversion of ore to liquid iron),
steel making (conversion of pig iron to liquid steel),
casting (solidification of the liquid steel),
roughing rolling/billet rolling (reducing size of blocks)
product rolling (finished shapes).

The principal raw materials for an integrated mill are iron ore, limestone, and coal (or coke). These materials are charged in batches into a blast furnace where the iron compounds in the ore give up excess oxygen and become liquid iron. At intervals of a few hours, the accumulated liquid iron is tapped from the blast furnace and either cast into pig iron or directed to other vessels for further steel making operations. Historically the Bessemer process was a major advancement in the production of economical steel, but it has now been entirely replaced by other processes such as the basic oxygen furnace.

Molten steel is cast into large blocks called blooms. During the casting process various methods are used, such as addition of aluminum, so that impurities in the steel float to the surface where they can be cut off the finished bloom.

Because of the energy cost and structural stress associated with heating and cooling a blast furnace, typically these primary steel making vessels will operate on a continuous production campaign of several years duration. Even during periods of low steel demand, it may not be feasible to let the blast furnace grow cold, though some adjustment of the production rate is possible.

Integrated mills are large facilities that are typically only economical to build in 2,000,000-ton per year annual capacity and up. Final products made by an integrated plant are usually large structural sections, heavy plate, strip, wire rod, railway rails, and occasionally long products such as bars and pipe.

A major environmental hazard associated with integrated steel mills is the pollution produced in the manufacture of coke, which is an essential intermediate product in the reduction of iron ore in a blast furnace.

Integrated mills may also adopt some of the processes used in mini-mills, such as arc furnaces and direct casting, to reduce production costs.

Minimill

A minimill is traditionally a secondary steel producer; however, Nucor (one of the world's largest steel producers) and Commercial Metals Company (CMC) use minimills exclusively. Usually it obtains most of its iron from scrap steel, recycled from used automobiles and equipment or byproducts of manufacturing. Direct reduced iron (DRI) is sometimes used with scrap, to help maintain desired chemistry of the steel, though usually DRI is too expensive to use as the primary raw steelmaking material. A typical mini-mill will have an electric arc furnace for scrap melting, a ladle furnace or vacuum furnace for precision control of chemistry, a strip or billet continuous caster for converting molten steel to solid form, a reheat furnace and a rolling mill.

Originally the minimill was adapted to production of bar products only, such as concrete reinforcing bar, flats, angles, channels, pipe, and light rails. Since the late 1980s, successful introduction of the direct strip casting process has made minimill production of strip feasible. Often a minimill will be constructed in an area with no other steel production, to take advantage of local markets, resources, or lower-cost labour. Minimill plants may specialize, for example, in making coils of rod for wire-drawing use, or pipe, or in special sections for transportation and agriculture.

Capacities of minimills vary: some plants may make as much as 3,000,000 tons per year, a typical size is in the range 200,000 to 400,000 tons per year, and some old or specialty plants may make as little as 50,000 tons per year of finished product. Nucor Corporation, for example, annually produces around 9,100,000 tons of sheet steel from its four sheet mills, 6,700,000 tons of bar steel from its 10 bar mills and 2,100,000 tons of plate steel from its two plate mills.

Since the electric arc furnace can be easily started and stopped on a regular basis, minimills can follow the market demand for their products easily, operating on 24-hour schedules when demand is high and cutting back production when sales are lower.

References

^ "Barrow". Ironbridge Gorge Museum Trust. Archived from the original on 2007-08-19. Retrieved 2007-08-25.
^ "POSCO Steel's Fourth Quarter Executive Board Meeting in India". POSCO. New Delhi. October 18, 2007. Archived from the original on 2012-07-20.

External links

[1] "Barrow". Ironbridge Gorge Museum Trust. Archived from the original on 2007-08-19. Retrieved 2007-08-25.

[2] "POSCO Steel's Fourth Quarter Executive Board Meeting in India". POSCO. New Delhi. October 18, 2007. Archived from the original on 2012-07-20.

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[2]

@@ Line 1: / Line 1: @@
+{{Short description|Plant for steelmaking}}
-{{Refimprove|date=May 2007}}
+{{For|a mechanical device that produced sparks for lighting in mines|mechanically powered flashlight#"Steel mills"}}
-[[Image:Letecky2.jpg|thumb|270px|Aerial view of [[Třinec Iron and Steel Works]]]]
+{{for|the band|Steel Mill}}
-[[Image:VysokePece1.jpg|thumb|270px|Blast furnaces of Třinec Iron and Steel Works]]
+{{Multiple issues|
-[[Image:SteelMill interior.jpg|thumb|right|300px|Interior of a steel mill]]
+{{Cleanup|date=October 2015|reason=See talk page}}
+{{Refimprove|date=October 2015}}
+}}
+[[File:Hoogovens.JPG|thumb|300px|Integrated steel mill in the [[Netherlands]]. The two large towers are [[blast furnace|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]].
+==History==
-A '''steel mill''' ([[British English]] and [[Australian English]] '''''steelworks''''') is an industrial plant for the manufacture of [[steel]].
+[[File:Otis Steel Mill, Ohio, 1929.jpg | thumb | Otis Steel Mill, Ohio, 1929]]
+Since the invention of the [[Bessemer process]], steel mills have replaced [[ironworks]], based on [[Puddling (metallurgy)|puddling]] or [[Finery forge|fining]] methods. New ways to produce steel appeared later: from scrap melted in an [[electric arc furnace]] and, more recently, from [[direct reduced iron]] processes.
+[[File:Allegheny Ludlum Steele Corp, Brackenridge, Pa.jpg| thumb | [[Brackenridge Works]], Pennsylvania, 1941]]
-Steel is an [[alloy]] of [[iron]] and [[carbon]]. It is produced in a two-stage process. First, [[iron ore]] is [[redox|reduced]] or [[smelting|smelted]] with [[Coke (fuel)|coke]] and [[limestone]] in a [[blast furnace]], producing molten iron which is either cast into [[pig iron]] or carried to the next stage as molten iron. In the second stage, known as [[steelmaking]], impurities such as [[sulfur]], [[phosphorus]], and excess [[carbon]] are removed and [[alloying]] elements such as [[manganese]], [[nickel]], [[chromium]] and [[vanadium]] are added to produce the exact steel required. In the late 19th Century and early 20th Century the world's largest steel mill was located in [[Barrow-in-Furness]], [[UK]]. Today, the world's largest steel mill is in [[Gwangyang]], [[South Korea]].<ref>{{cite web |url= http://www.ironbridge.org.uk/about_us/ironbridge_archaeology/projects/barrow/|title= Barrow|accessdate=2007-08-25 |publisher= [[Ironbridge Gorge]] Museum Trust}}</ref><ref>[http://posco-india.com/website/press-room/news/posco-board-meeting-in-india.htm http://posco-india.com/website/press-room/news/posco-board-meeting-in-india.htm POSCO Steel’s Fourth Quarter Executive Board Meeting in India] New Delhi, October 18, 2007</ref>
+In the late 19th and early 20th centuries the world's largest steel mill was the [[Barrow Hematite Steel Company|Barrow Hematite Steel Company steelworks]] located in [[Barrow-in-Furness]], [[United Kingdom]]. Today, the world's largest steel mill is in [[Gwangyang]], [[South Korea]].<ref>{{cite web |url=http://www.ironbridge.org.uk/about_us/ironbridge_archaeology/projects/barrow/ |title=Barrow |access-date=2007-08-25 |publisher=[[Ironbridge Gorge]] Museum Trust |url-status=dead |archive-url=https://web.archive.org/web/20070819160207/http://www.ironbridge.org.uk/about_us/ironbridge_archaeology/projects/barrow/ |archive-date=2007-08-19 }}</ref><ref>{{cite web |url=http://posco-india.com/website/press-room/news/posco-board-meeting-in-india.htm |title=POSCO Steel's Fourth Quarter Executive Board Meeting in India |archive-url=https://archive.today/20120720005735/http://posco-india.com/website/press-room/news/posco-board-meeting-in-india.htm |archive-date=2012-07-20 |url-status=dead |location=New Delhi |date=October 18, 2007 |website=[[POSCO]] }}</ref>
-Steel mills turn molten steel into blooms, ingots, slabs and sheet through [[Casting (metalworking)|casting]], [[hot rolling]] and [[cold rolling]].
 ==Integrated mill{{Anchor|Integrated mill}}==
+[[File:Lackawanna steel plant 1903.png|thumb|Plan of the [[Lackawanna Steel Company|Lackawanna Steel]] plant in [[Buffalo, New York]] ca. 1903, showing the various elements of an integrated steel mill]]
+[[Image:VysokePece1.jpg|thumb|Blast furnaces of [[Třinec Iron and Steel Works]]]]
+[[Image:SteelMill interior.jpg|thumb|Interior of a steel mill]]
-An integrated steel mill has all the functions for primary steel production:
+An integrated steel mill has all the functions for primary steel
+production:
-* iron making (conversion of [[ore]] to liquid iron),
+* [[ironmaking|iron making]] (conversion of [[ore]] to liquid iron),
-* steelmaking (conversion of [[pig iron]] to liquid steel),
+* [[steelmaking|steel making]] (conversion of [[pig iron]] to liquid steel),
-* casting (solidification of the liquid steel),
+* [[casting]] (solidification of the liquid steel),
-* roughing rolling/billet rolling (reducing size of blocks)
+* [[Rolling_(metalworking)|roughing rolling/billet rolling]] (reducing size of blocks)
-* product rolling (finished shapes).
+* [[Rolling mill|product rolling]] (finished shapes).
-The principal raw materials for an integrated mill are iron ore, limestone, and coal (or coke).  These materials are charged in batches into a [[blast furnace]] where the iron compounds in the ore give up excess oxygen and become liquid iron. At intervals of a few hours, the accumulated liquid iron is tapped from the blast furnace and either cast into [[pig iron]] or directed to other vessels for further steelmaking operations. Historically the [[Bessemer process]] was a major advancement in the production of economical steel, but it has now been entirely replaced by other processes such as the [[basic oxygen furnace]].
+The principal raw materials for an integrated mill are iron ore, limestone, and coal (or coke).  These materials are charged in batches into a [[blast furnace]] where the iron compounds in the ore give up excess oxygen and become liquid iron. At intervals of a few hours, the accumulated liquid iron is tapped from the blast furnace and either cast into [[pig iron]] or directed to other vessels for further steel making operations. Historically the [[Bessemer process]] was a major advancement in the production of economical steel, but it has now been entirely replaced by other processes such as the [[basic oxygen furnace]].
-Molten steel is cast into large blocks called "blooms".  During the casting process various methods are used, such as addition of [[aluminum]], so that impurities in the steel float to the surface where they can be cut off the finished bloom.
+Molten steel is cast into large blocks called ''blooms''. During the casting process various methods are used, such as addition of [[aluminum]], so that impurities in the steel float to the surface where they can be cut off the finished bloom.
-Because of the energy cost and structural stress associated with heating and cooling a blast furnace, typically these primary steelmaking vessels will operate on a continuous production campaign of several years duration. Even during periods of low steel demand, it may not be feasible to let the blast furnace grow cold, though some adjustment of the production rate is possible.
+Because of the energy cost and structural stress associated with heating and cooling a blast furnace, typically these primary steel making vessels will operate on a continuous production campaign of several years duration. Even during periods of low steel demand, it may not be feasible to let the blast furnace grow cold, though some adjustment of the production rate is possible.
-Integrated mills are large facilities that are typically only economical to build in 2,000,000 ton per year annual capacity and up.  Final products made by an integrated plant are usually large structural sections, heavy plate, strip, wire rod, [[rail tracks|railway rails]],  and occasionally [[long steel products|long products]] such as [[Structural steel|bars]] and [[pipe (material)|pipe]].
+Integrated mills are large facilities that are typically only economical to build in 2,000,000-ton per year annual capacity and up. Final products made by an integrated plant are usually large structural sections, heavy plate, strip, wire rod, [[rail tracks|railway rails]], and occasionally [[long steel products|long products]] such as [[Structural steel|bars]] and [[pipe (material)|pipe]].
-A major environmental hazard associated with integrated steel mills is the pollution produced in the manufacture of [[coke (fuel)|coke]], which is an essential intermediate product in the reduction of iron ore in a blast furnace.
+A major [[environmental hazard]] associated with integrated steel mills is the pollution produced in the manufacture of [[coke (fuel)|coke]], which is an essential intermediate product in the reduction of iron ore in a blast furnace.
 Integrated mills may also adopt some of the processes used in mini-mills, such as arc furnaces and direct casting, to reduce production costs.
+==Minimill{{Anchor|Minimill}}==
-World integrated steel production capacity is at or close to world demand, so competition between suppliers results in only the most efficient producers remaining viable.  However, due to the large employment of integrated plants, often governments will financially assist an obsolescent facility rather than take the risk of having thousands of workers thrown out of jobs.{{Nonspecific|date=July 2007}}
+[[File:Block-Grobstrasse Witten.tif|thumb|An ingot of steel entering a rolling mill]]
+A minimill is traditionally a secondary steel producer; however, [[Nucor]] (one of the world's largest steel producers) and [[Commercial Metals Company | Commercial Metals Company (CMC)]] use minimills exclusively.  Usually it obtains most of its iron from [[scrap]] steel, recycled from used automobiles and equipment or byproducts of manufacturing. [[Direct reduced iron]] (DRI) is sometimes used with scrap, to help maintain desired chemistry of the steel, though usually DRI is too expensive to use as the primary raw steelmaking material.  A typical mini-mill will have an [[electric arc furnace]] for scrap melting, a [[ladle (metallurgy)|ladle furnace]] or [[vacuum furnace]] for precision control of chemistry, a strip or billet [[Continuous Casting|continuous caster]] for converting molten steel to solid form, a [[reheat furnace]] and a [[rolling mill]].
+Originally the minimill was adapted to production of bar products only, such as [[concrete]] [[rebar|reinforcing bar]], flats, angles, channels, pipe, and light rails. Since the late 1980s, successful introduction of the [[Continuous_casting#Direct_strip_casting|direct strip casting]] process has made minimill production of strip feasible.  Often a minimill will be constructed in an area with no other steel production, to take advantage of local markets, resources, or lower-cost labour.  Minimill plants may specialize, for example, in making coils of rod for [[wire drawing|wire-drawing]] use, or pipe, or in special sections for transportation and agriculture.
-==Mini mill{{Anchor|Mini mill}}==
-A mini-mill is traditionally a secondary steel producer; however, [[Nucor]] (one of the world's largest steel producers), as well as one of its competitors, Commercial Metals Company (CMC) use mini-mills exclusively.  Usually it obtains most of its iron from [[scrap]] steel, recycled from used automobiles and equipment or byproducts of manufacturing. [[Direct reduced iron]] (DRI) is sometimes used with scrap, to help maintain desired chemistry of the steel, though usually DRI is too expensive to use as the primary raw steelmaking material.  A typical mini-mill will have an [[electric arc furnace]] for scrap melting, a ladle furnace or vacuum furnace for precision control of chemistry, a strip or billet [[Continuous Casting|continuous caster]] for converting molten steel to solid form, a [[reheat furnace]] and a [[rolling mill]].
+Capacities of minimills vary: some plants may make as much as 3,000,000 tons per year, a typical size is in the range 200,000 to 400,000 tons per year, and some old or specialty plants may make as little as 50,000 tons per year of finished product. [[Nucor Corporation]], for example, annually produces around 9,100,000 tons of sheet steel from its four sheet mills, 6,700,000 tons of bar steel from its 10 bar mills and 2,100,000 tons of plate steel from its two plate mills.
-Originally the mini-mill concept was adapted to production of bar products only, such as [[concrete]] [[rebar|reinforcing bar]], flats, angles, channels, pipe, and light rails. Since the late 1980s, successful introduction of the [[direct strip casting]] process has made mini-mill production of strip feasible.  Often a mini-mill will be constructed in an area with no other steel production, to take advantage of local resources and lower-cost labour.  Mini-mill plants may specialize, for example, making coils of rod for [[wire drawing|wire-drawing]] use, or pipe, or in special sections for transportation and agriculture.
+Since the electric arc furnace can be easily started and stopped on a regular basis, minimills can follow the market demand for their products easily, operating on 24-hour schedules when demand is high and cutting back production when sales are lower. <!-- Origins of steel mills, history, notable producers, references, PICTURES anyone? -->
-Capacities of mini-mills vary; some plants may make as much as 3,000,000 tons per year, a typical size is in the range 200,000 to 400,000 tons per year, and some old or specialty plants may make as little as 50,000 tons per year of finished product. [[Nucor Corporation]], for example, annually produces around 9,100,000 tons of sheet steel from its 4 sheet mills, 6,700,000 tons of bar steel from its 10 bar mills and 2,100,000 tons of plate steel from its 2 plate mills.
-Since the electric arc furnace can be easily started and stopped on a regular basis, mini-mills can follow the market demand for their products easily, operating on 24 hour schedules when demand is high and cutting back production when sales are lower. <!-- Origins of steel mills, history, notable producers, references, PICTURES anyone? -->
 ==See also==
 * [[Foundry]]
 * [[List of steel producers]]
+* [[Steel#Industry|Steel § Industry]]
 ==References==
+{{Reflist}}
-<references />
 ==Further reading==
-McGannon, Harold E. editor (1971). ''The Making, Shaping and Treating of Steel: Ninth Edition''. Pittsburgh, Pennsylvania: United States Steel Corporation
+* McGannon, Harold E. (editor) (1971). ''The Making, Shaping and Treating of Steel: Ninth Edition''. Pittsburgh, Pennsylvania: United States Steel Corporation.
 ==External links==
+{{Commons|Steel mill}}
-* [http://www.stahlseite.de/ An extensive picture gallery about all methods of making and shaping of iron and steel in North America and Europe]
+* [http://www.travelchannel.com/video/steel-city-usa Travel Channel video 1 of the Homestead Works]
-* [http://myweb.tiscali.co.uk/clydebridge History of steelworks in Scotland]
+* [http://www.stahlseite.de/ An extensive picture gallery of all methods of production in North America and Europe]
+* [http://myweb.tiscali.co.uk/clydebridge History of steelworks in Scotland] {{Webarchive|url=https://web.archive.org/web/20180722214317/http://myweb.tiscali.co.uk/clydebridge/ |date=2018-07-22 }}
+* [http://www.steelonthenet.com/kb/eaf-technology-trends.html Trends in EAF quality capability 1980–2010]
+{{Iron and steel production}}
-[[Category:Steelmaking]]
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+{{authority control}}
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