Ferrous metallurgy

{{Short description|Metallurgy of iron and its alloys}} [[File:Bas fourneau.png|thumb|upright|[[Bloomery]] [[smelting]] during the [[Middle Ages]]]]

'''Ferrous metallurgy''' is the [[metallurgy]] of [[iron]] and its [[alloy]]s. The earliest surviving [[prehistory|prehistoric]] iron artifacts, from the 4th millennium BC in [[Egypt]],<ref>{{cite journal |last= Rehren |first= T. |year= 2013 |title= 5,000 years old Egyptian iron beads made from hammered meteoritic iron |journal= Journal of Archaeological Science |volume= 40 |issue= 12 |pages= 4785–4792 |doi= 10.1016/j.jas.2013.06.002 |doi-access= free |bibcode= 2013JArSc..40.4785R |url = http://discovery.ucl.ac.uk/1430496/1/Rehren_et_al_2013_Petrie_iron_beads_JAS_40.pdf}}</ref> were made from [[Meteorite|meteoritic]] [[Iron–nickel alloy|iron-nickel]].<ref name=ephotos /> It is not known when or where the [[smelting]] of iron from [[ore]]s began, but by the end of the 2nd millennium BC, iron was being produced from [[iron ore]]s in the region from Greece to India,<ref name=ReferenceB>Riederer, Josef; Wartke, Ralf-B.: "Iron", Cancik, Hubert; Schneider, Helmuth (eds.): [[Brill's New Pauly]], Brill 2009</ref><ref name=UCP>Early Antiquity By I.M. Drakonoff. 1991. [[University of Chicago Press]]. {{ISBN|0-226-14465-8}}. p. 372</ref><ref>{{Cite book|last= Rao|first= Kp|chapter= Iron Age in South India: Telangana and Andhra Pradesh|url= https://www.researchgate.net/publication/332103484 |access-date=12 April 2022|language= en |title=Iron Age in South Asia |year=2018 |isbn= 978-4-9909150-1-8 |publisher=Research Group for South Asian Archaeology |editor-last1=Uesugi |editor-first1=Akinori}}</ref><ref name=miller>{{cite journal |last1= Miller |first1= Duncan E. |last2= van der Merwe |first2= N.J. |title= Early Metal Working in Sub-Saharan Africa: A Review of Recent Research |year= 1994 |journal= Journal of African History |volume= 35 |pages= 1–36 |doi= 10.1017/s0021853700025949|s2cid= 162330270 }}</ref><ref name=Stuiver>{{cite journal |last1= Stuiver |first1= Minze |last2= van der Merwe |first2= N.J. |year= 1968 |title= Radiocarbon Chronology of the Iron Age in Sub-Saharan Africa |journal= Current Anthropology |volume= 9 |pages= 54–58 |doi= 10.1086/200878 |s2cid= 145379030}}</ref><ref>Waldbaum (1978).</ref>{{page needed|date=February 2022}} The use of [[wrought iron]] (worked iron) was known by the 1st millennium BC, and its spread defined the [[Iron Age]]. During the medieval period, smiths in Europe found a way of producing wrought iron from [[cast iron]], in this context known as [[pig iron]], using [[finery forge]]s. All these processes required [[charcoal]] as [[fuel]].

By the 4th century BC southern India had started exporting [[wootz steel]], with a carbon content between [[pig iron]] and wrought iron, to ancient China, Africa, the Middle East, and Europe.{{citation needed|date= March 2021}} Archaeological evidence of [[cast iron]] appears in 5th-century BC China.<ref name=Wagner/> New methods of producing it by [[carburizing]] bars of iron in the [[cementation process]] were devised in the 17th century. During the [[Industrial Revolution]], new methods of producing [[bar iron]] emerged, by substituting [[charcoal]] in favor of [[Coke (fuel)|coke]], and these were later applied to produce [[steel]], ushering in a new era of greatly increased use of iron and steel that some contemporaries described as a new "Iron Age".<ref name=Williams>{{Citation |last= Williams |first= David |year= 1867 |title= The Iron Age [weekly journal] |journal= Iron Age |publisher= David Williams |location= New York |oclc= 5257259 |lccn= sc82008005 |issn= 0021-1508}}</ref>

In the late 1850s [[Henry Bessemer]] invented a [[Bessemer process|new steelmaking process]] which involved blowing air through molten pig-iron to burn off carbon, and so producing mild steel. This and other 19th-century and later steel-making processes have displaced [[wrought iron]]. Today, wrought iron is no longer produced on a commercial scale, having been displaced by the functionally equivalent mild or low-carbon steel.<ref name=Tylecote/>{{rp|145}}

==Meteoric iron== {{Main|Meteoric iron}} [[File:Willamette Meteorite AMNH.jpg|thumb|upright|[[Willamette Meteorite]], the sixth largest in the world, is an [[iron-nickel meteorite]].]] [[File:Widmanstatten IronMet.JPG|thumb|Iron meteorites consist overwhelmingly of nickel-iron alloys. The metal taken from these meteorites is known as meteoric iron and was one of the earliest sources of usable iron available to humans.]]

Iron was extracted from [[iron–nickel alloy]]s, which comprise about 6% of all [[meteorite fall|meteorites that fall]] on the [[Earth]]. That source can often be identified with certainty because of the unique [[crystal]]line features ([[Widmanstätten pattern]]s) of that material, which are preserved when the metal is worked cold or at low temperature. Those artifacts include, for example, spear tips and ornaments from [[ancient Egypt]] and [[Sumer]] around 4000 BC.<ref name=Tylecote3>Tylecote (1992). p. 3.</ref>

These early uses appear to have been largely ceremonial or decorative. Meteoric iron is very rare, and the metal was probably very expensive, perhaps more expensive than [[gold]]. The early [[Hittites]] are known to have [[barter]]ed iron (meteoric or smelted) for [[silver]], at a rate of 40 times the iron's weight, with [[Assyria]] in the first centuries of the [[2nd millennium BC|second millennium BC]].<ref name=Veenhof>{{cite book|last1=Veenhof|first1=Klaas |author-link1=Klaas Veenhof|last2=Eidem|first2=Jesper|author-link2=Jesper Eidem|title=Mesopotamia : Annäherungen|url=https://books.google.com/books?id=vYMmrenUywQC&pg=PA84|year=2008|publisher=Saint-Paul|isbn=978-3-525-53452-6|pages=84}}</ref>

Meteoric iron was also fashioned into tools in the [[Arctic]] when the [[Thule people]] of [[Greenland]] began making [[harpoon]]s, knives, [[ulu]]s and other edged tools from pieces of the [[Cape York meteorite]]. Typically pea-size bits of metal were cold-hammered into disks and fitted to a bone handle.<ref name=ephotos /> These artifacts were also used as trade goods with other Arctic peoples: tools made from the Cape York meteorite have been found in archaeological sites more than {{convert|1000|miles}} distant. When the [[United States|American]] polar explorer [[Robert Peary]] shipped the largest piece of the meteorite to the [[American Museum of Natural History]] in [[New York City]] in 1897, it still weighed over 33 [[ton]]s. Another example of a late use of meteoric iron is an [[adze]] from around 1000 AD found in [[Sweden]].<ref name=ephotos/>

==Native iron== {{Main|Telluric iron}} [[Native metal|Native]] iron in the metallic state occurs rarely as small inclusions in certain [[basalt]] rocks. Besides meteoritic iron, Thule people of Greenland have used native iron from the [[Disko Island|Disko]] region.<ref name=ephotos/>

==Iron smelting and the Iron Age== {{Iron Age|expand=Related topics}}

Iron smelting—the extraction of usable metal from [[oxidation|oxidized]] iron ores—is more difficult than [[tin]] and [[copper]] smelting. While these metals and their alloys can be cold-worked or melted in relatively simple furnaces (such as the kilns used for [[pottery]]) and cast into molds, smelted iron requires hot-working and can be melted only in specially designed furnaces. Iron is a common impurity in copper ores and iron ore was sometimes used as a [[Flux (metallurgy)|flux]], thus it is not surprising that humans mastered the technology of smelted iron only after several millennia of [[bronze|bronze metallurgy]].<ref name=Tylecote3/>

The place and time for the discovery of iron smelting is not known, partly because of the difficulty of distinguishing metal extracted from nickel-containing ores from hot-worked meteoritic iron.<ref name=ephotos /> The archaeological evidence seems to point to the Middle East area, during the [[Bronze Age]] in the 3rd millennium BC. However, [[wrought iron]] artifacts remained a rarity until the 12th century BC.

The [[Iron Age]] is conventionally defined by the widespread replacement of [[bronze]] weapons and tools with those of iron and steel.<ref name=Waldbaum56>Waldbaum (1978). pp. 56–58.</ref> This transition happened at different times in different places, as the technology spread. Mesopotamia was fully into the Iron Age by 900 BC. Although Egypt produced iron artifacts, bronze remained dominant until its conquest by Assyria in 663 BC. The Iron Age began in India about 1200 BC, in Central Europe about 800 BC, and in China about 300 BC.<ref name=Ceccarelli /><ref>White, W. C.: "Bronze Culture of Ancient China", p. 208. University of Toronto Press, 1956.</ref> Around 500 BC, the [[Nubia]]ns, who had learned from the Assyrians the use of iron and were expelled from Egypt, became major manufacturers and exporters of iron.<ref>Collins, Rober O. and Burns, James M. ''The History of Sub-Saharan Africa''. New York: Cambridge University Press, p. 37. {{ISBN|978-0-521-68708-9}}.</ref> The development of bloomery versus cast iron across regions may be due to influence by the applications demanded of iron within the respective socio-political environments<ref>{{cite journal|last1=Liu|first1=Y.|last2=Wood|first2=J.|title=Questioning Diversity (of Iron) in the Workplace: Bloomery Iron, Cast Iron, China and the West|journal=Internet Archaeology|date=2025|issue=69|doi=10.11141/ia.69.14|doi-access=free|url=https://intarch.ac.uk/journal/issue69/14/index.html}}</ref>

In pre-Roman Britain, iron smelting was certainly firmly established during the Middle Iron Age in Yorkshire and may be linked to the [[Arras culture]]. The large-scale, communal nature of the smelting at Thornton suggests it supported the significant demand for iron tools and funerary goods required by these communities.<ref>{{cite journal|last1=van Tongeren|first1=Tim|title=Furnace Fields: Iron Age and Roman Metalworking between York and the Humber|journal=Internet Archaeology|date=2026|issue=71|doi=10.11141/ia.71.11|doi-access=free|url=https://intarch.ac.uk/journal/issue71/11/index.html}}</ref>

===Ancient Near East=== [[File:Metal production in Ancient Middle East.svg|thumb|upright=1.65|Mining areas of the ancient [[Middle East]]. Boxes colors: [[arsenic]] in brown, [[copper]] in red (the important mines of the [[Arabah]], [[Timna Valley#Copper mining|Timna]] and [[Wadi Feynan|Feynan]], are missing from the map), [[tin]] in grey, iron in reddish brown, gold in yellow, silver in white and [[lead]] in black. The yellow area stands for [[Arsenical bronze|arsenic bronze]], while grey area stands for tin [[bronze]].]]

About 1500 BC, increasing numbers of non-meteoritic, smelted iron objects appeared in [[Mesopotamia]], Anatolia and Egypt.<ref name=ephotos>{{cite journal |last= Photos |first= E. |title= The Question of Meteoritic versus Smelted Nickel-Rich Iron: Archaeological Evidence and Experimental Results |journal= World Archaeology |volume= 20 |issue= 3 |pages= 403–421 |year= 1989 |s2cid= 5908149 |doi= 10.1080/00438243.1989.9980081 |jstor= 124562}}</ref> Nineteen meteoric iron objects were found in the [[tomb]] of [[Egypt]]ian ruler [[Tutankhamun]], who died in 1323 BC, including an iron dagger with a golden hilt, an [[Eye of Horus]], the mummy's head-stand and sixteen models of an artisan's tools.<ref>''The Tomb of Tut-Ankh-Amen: Discovered by the Late Earl of Carnarvon and Howard Carter, Volume 3''</ref> An Ancient Egyptian sword bearing the name of pharaoh [[Merneptah]] as well as a [[battle axe]] with an iron blade and gold-decorated bronze shaft were both found in the excavation of [[Ugarit]].<ref name=cowen>Richard Cowen, ''The Age of Iron'', Chapter 5 in a series of essays on Geology, History, and People prepares for a course of the University of California at Davis. [http://mygeologypage.ucdavis.edu/cowen/~GEL115/115CH5.html Online version] {{webarchive|url=https://web.archive.org/web/20100314155922/http://mygeologypage.ucdavis.edu/cowen/~GEL115/115CH5.html |date=2010-03-14 }} accessed on 2010-02-11.</ref>

Although iron objects dating from the [[Bronze Age]] have been found across the Eastern Mediterranean, bronzework appears to have greatly predominated during this period.<ref name=Waldbaum23>Waldbaum (1978): 23.</ref> As the technology spread, iron came to replace bronze as the dominant metal used for tools and weapons across the Eastern Mediterranean (the [[Levant]], [[Cyprus]], [[Greece]], [[Crete]], Anatolia and Egypt).<ref name=Waldbaum56/>

Iron was originally smelted in [[bloomery|bloomeries]], furnaces where [[bellows]] were used to force air through a pile of iron ore and burning [[charcoal]]. The [[carbon monoxide]] produced by the charcoal reduced the [[iron oxide]] from the ore to metallic iron. The bloomery, however, was not hot enough to melt the iron, so the metal collected in the bottom of the furnace as a spongy mass, or ''bloom''. Workers then repeatedly beat and folded it to force out the molten [[slag]]. This laborious, time-consuming process produced [[wrought iron]], a malleable but fairly soft alloy.<ref>{{Cite book|last=Smil|first=Vaclav|title=Still the Iron Age|publisher=Butterworth-Heinemann|year=2016|isbn=978-0128042335|location=Oxford, England|pages=2–5|language=English}}</ref>

Concurrent with the transition from bronze to iron was the discovery of [[carburization]], the process of adding carbon to wrought iron. While the iron bloom contained some carbon, the subsequent hot-working [[oxidation|oxidized]] most of it. Smiths in the Middle East discovered that wrought iron could be turned into a much harder product by heating the finished piece in a bed of charcoal, and then [[quench]]ing it in water or oil. This procedure turned the outer layers of the piece into [[steel]], an alloy of iron and [[iron carbide]]s, with an inner core of less brittle iron.

====Theories on the origin of iron smelting==== The development of iron smelting was traditionally attributed to the [[Hittites]] of Anatolia of the Late [[Bronze Age]].<ref name=mulhy>Muhly, James D. 'Metalworking/Mining in the Levant' pp. 174–183 in ''Near Eastern Archaeology'' ed. Suzanne Richard (2003), pp. 179–180.</ref> It was believed that they maintained a monopoly on iron working, and that their empire had been based on that advantage. According to that theory, the ancient [[Sea Peoples]], who invaded the Eastern Mediterranean and destroyed the Hittite empire at the end of the Late Bronze Age, were responsible for spreading the knowledge through that region. This theory is no longer held in the mainstream of scholarship,<ref name=mulhy /> since there is no archaeological evidence of the alleged Hittite monopoly. While there are some iron objects from Bronze Age Anatolia, the number is comparable to iron objects found in Egypt and other places of the same time period, and only a small number of those objects were weapons.<ref name=Waldbaum23/>

A more recent theory claims that the development of iron technology was driven by the disruption of the [[copper]] and [[tin]] trade routes, due to the collapse of the empires at the end of the Late Bronze Age.<ref name=mulhy/> These metals, especially tin, were not widely available and metal workers had to transport them over long distances, whereas iron ores were widely available. However, no known archaeological evidence suggests a shortage of bronze or tin in the Early Iron Age.<ref>Muhly 2003: 180.</ref> Bronze objects remained abundant, and these objects have the same percentage of tin as those from the Late Bronze Age.

===Indian subcontinent=== [[File:Iron Pillar, Delhi, May 2008.jpg|thumb|upright|The [[iron pillar of Delhi]]]]

The history of ferrous metallurgy in the Indian subcontinent began in the 2nd millennium BC. Archaeological sites in the [[Gangetic plains]] have yielded iron implements dated between 1800 and 1200 BC.<ref name=Tewari>{{cite journal |last=Tewari |first=Rakesh |author-link=Rakesh Tewari |title=The origins of iron-working in India: new evidence from the Central Ganga Plain and the Eastern Vindhyas |journal=Antiquity |volume=77 |pages=536–544 |number=297 |year=2003 |url=http://antiquity.ac.uk/projgall/tewari/tewari.pdf |doi=10.1017/s0003598x00092590 |url-status=live |archive-url=https://web.archive.org/web/20160305222813/http://antiquity.ac.uk/projgall/tewari/tewari.pdf |archive-date=2016-03-05 |citeseerx=10.1.1.403.4300 |s2cid=14951163 }}</ref> By the early 13th century BC, iron smelting was practiced on a large scale in India.<ref name=Tewari /> In [[Southern India]] (present day [[Mysore]]) iron was in use 12th to 11th centuries BC.<ref name=UCP /> The technology of iron metallurgy advanced in the politically stable [[Maurya Empire|Maurya]] period<ref>[[J. F. Richards]] et al. (2005).''[[The New Cambridge History of India]]''. Cambridge University Press. {{ISBN|0-521-36424-8}}. p. 64</ref> and during a period of peaceful settlements in the 1st millennium BC.<ref name=UCP/>

Iron artifacts such as [[nail (fastener)|spikes]], [[knife|knives]], [[dagger]]s, [[arrow]]-heads, [[bowl (vessel)|bowls]], [[spoon]]s, [[saucepan]]s, [[axe]]s, [[chisel]]s, [[tongs]], door fittings, etc., dated from 600 to 200 BC, have been discovered at several archaeological sites of India.<ref name=Ceccarelli>Marco Ceccarelli (2000). ''International Symposium on History of Machines and Mechanisms: Proceedings HMM Symposium''. Springer. {{ISBN|0-7923-6372-8}}. p. 218</ref> The Greek historian [[Herodotus]] wrote the first [[Western world|western]] account of the use of iron in India.<ref name=Ceccarelli /> The Indian mythological texts, the [[Upanishad]]s, have mentions of weaving, pottery and metallurgy, as well.<ref>[[Patrick Olivelle]] (1998). ''Upanisads''. Oxford University Press. {{ISBN|0-19-283576-9}}. p. xxix</ref> The [[Roman Empire|Romans]] had high regard for the excellence of steel from India in the time of the [[Gupta Empire]].<ref name=durant />

[[File:Dagger India Louvre MR13434.jpg|left|upright|thumb|Dagger and its scabbard, India, 17th–18th century. Blade: [[Damascus steel]] inlaid with gold; hilt: jade; scabbard: steel with engraved, chased and gilded decoration.]]

Perhaps as early as 500 BC, although certainly by 200 AD, high-quality steel was produced in southern India by the [[crucible steel|crucible technique]]. In this system, high-purity wrought iron, charcoal, and glass were mixed in a crucible and heated until the iron melted and absorbed the carbon.<ref name=Juleff /> Iron chain was used in Indian [[suspension bridge]]s as early as the 4th century.<ref>{{cite web|url=https://www.britannica.com/eb/article-9070493/suspension-bridge|title=Suspension bridge – engineering|website=britannica.com|url-status=live|archive-url=https://web.archive.org/web/20071016155902/https://www.britannica.com/eb/article-9070493/suspension-bridge|archive-date=2007-10-16}}</ref>

[[Wootz steel]] was produced in India and [[Sri Lanka]] from around 300 BC.<ref name=Juleff>{{cite journal|author=G. Juleff|title=An ancient wind powered iron smelting technology in Sri Lanka|journal=[[Nature (journal)|Nature]]|volume=379|issue=3|pages=60–63|year=1996|doi=10.1038/379060a0|bibcode = 1996Natur.379...60J |s2cid=205026185}}</ref> Wootz steel is famous from [[Classical Antiquity]] for its durability and ability to hold an edge. When asked by [[King Porus]] to select a gift, [[Alexander the Great|Alexander]] is said to have chosen, over [[gold]] or [[silver]], thirty pounds of steel.<ref name=durant /> Wootz steel was originally a complex alloy with iron as its main component together with various [[trace element]]s. Recent studies have suggested that its qualities may have been due to the formation of [[carbon nanotubes]] in the metal.<ref name=sword>{{cite journal |last= Sanderson |first= Katharine |title= Sharpest cut from nanotube sword: Carbon nanotech may have given swords of Damascus their edge |journal=[[Nature (journal)|Nature]] |date= 2006-11-15 |doi= 10.1038/news061113-11 |s2cid= 136774602 |url= http://www.nature.com/news/2006/061113/full/061113-11.html |access-date= 2006-11-17 |url-status= live |archive-url= https://web.archive.org/web/20061119231011/http://www.nature.com/news/2006/061113/full/061113-11.html |archive-date= 2006-11-19|doi-access= free }}</ref> According to [[Will Durant]], the technology passed to the [[Persian people|Persians]] and from them to [[Arab]]s who spread it through the Middle East.<ref name=durant>Will Durant (), ''[[The Story of Civilization]] I: Our Oriental Heritage''</ref> In the 16th century, the [[Dutch Empire|Dutch]] carried the technology from South India to Europe, where it was mass-produced.<ref>Roy Porter (2003). ''The Cambridge History of Science''. Cambridge University Press. {{ISBN|0-521-57199-5}}. p. 684</ref>

Steel was produced in [[Sri Lanka]] from 300 BC<ref name=Juleff /> by furnaces blown by the [[Monsoon of Indian subcontinent|monsoon winds]]. The furnaces were dug into the crests of hills, and the wind was diverted into the [[air vents]] by long trenches. This arrangement created a zone of high pressure at the entrance, and a zone of low pressure at the top of the furnace. The flow is believed to have allowed higher temperatures than bellows-driven furnaces could produce, resulting in better-quality iron.<ref name=Juleff1>{{cite journal|author=Juleff, G.|title=An ancient wind powered iron smelting technology in Sri Lanka|journal=[[Nature (journal)|Nature]]|volume=379|issue=3|pages=60–63|year=1996|doi=10.1038/379060a0|bibcode = 1996Natur.379...60J |s2cid=205026185}}</ref><ref>{{cite web |url=http://www.fluent.com/about/news/newsletters/04v13i1/a27.htm |title=ANSYS Fluent Software: CFD Simulation |access-date=2009-01-23 |url-status=live |archive-url=https://web.archive.org/web/20090221092502/http://fluent.com/about/news/newsletters/04v13i1/a27.htm |archive-date=2009-02-21 }}</ref><ref>Simulation of air flows through a Sri Lankan wind driven furnace, submitted to J. Arch. Sci, 2003.</ref> Steel made in Sri Lanka was traded extensively within the region and in the [[Islamic world]]. {{See also|Steel#Wootz and Damascus}}

One of the world's foremost metallurgical curiosities is an [[iron pillar of Delhi|iron pillar]] located in the [[Qutb complex]] in [[Delhi]]. The pillar is made of wrought iron (98% [[iron|Fe]]), is almost seven meters high and weighs more than six tonnes.<ref>R. Balasubramaniam (2002), ''Delhi Iron Pillar: New Insights''. Aryan Books International, Delhi {{ISBN|81-7305-223-9}}. {{cite web |url=http://www.infinityfoundation.com/mandala/t_rv/t_rv_agraw_delhi_frameset.htm |title=Review: Delhi Iron Pillar: New Insights |access-date=2007-04-27 |url-status=live |archive-url=https://web.archive.org/web/20070927224815/http://www.infinityfoundation.com/mandala/t_rv/t_rv_agraw_delhi_frameset.htm |archive-date=2007-09-27 }} {{cite web |url=http://home.iitk.ac.in/~bala/journalpaper/journal/index.htm |title=List of Publications on Indian Archaeometallurgy |access-date=2007-04-27 |url-status=live |archive-url=https://web.archive.org/web/20070312111546/http://home.iitk.ac.in/%7Ebala/journalpaper/journal/index.htm |archive-date=2007-03-12 }}</ref> The pillar was erected by [[Chandragupta II]] Vikramaditya and has withstood 1,600 years of exposure to heavy rains with relatively little [[corrosion]].

Numerous scholars have suggested that the [[Afanasievo culture]] may be responsible for the introduction of [[metallurgy]] to [[China]].<ref name="JR375">{{cite journal |last1=Rawson |first1=Jessica |title=China and the steppe: reception and resistance |journal=Antiquity |date=April 2017 |volume=91 |issue=356 |pages=375–388 |doi=10.15184/aqy.2016.276 |url=https://www.researchgate.net/publication/315991114|quote=The development of several key technologies in China —bronze and iron metallurgy and horse-drawn chariots— arose out of the relations of central China, of the Erlitou period (c. 1700–1500 BC), the Shang (c.1500–1046 BC) and the Zhou (1046–771 BC) dynasties, with their neighbours in the steppe.}}</ref><ref>{{cite book |last=Baumer |first=Christoph |author-link=Christoph Baumer |date=11 December 2012 |title=The History of Central Asia: The Age of the Steppe Warriors |url=https://books.google.com/books?id=yglkwD7pKV8C |publisher=[[I.B. Tauris]] |page=122 |isbn=978-1780760605 }}</ref> In particular, contact between the Afanasievo culture and the [[Majiayao culture]] and the [[Qijia culture]] are considered for the transmission of bronze technology.<ref>{{cite journal |last1=Wan |first1=Xiang |title=Early development of bronze metallurgy in Eastern Eurasia |journal=Sino-Platonic Papers |date=2011 |volume=213 |pages=4–5 |url=https://www.academia.edu/1086939|quote="The metal-using Afanasievo culture is probably the origin of bronze metallurgy in Northwest China." (...) "Therefore it is conspicuous that one of the earliest bronze cultures in China, the [[Qijia culture]], might well have borrowed its bronze metallurgy from the Steppe, via Siba, [[Tianshanbeilu]], and cultures in the Altai region."}}</ref>

In 2008, two iron fragments were excavated at the [[Qijia culture#Mogou site|Mogou site]], in [[Gansu]]. They have been dated to the 14th century BC, belonging to the period of [[Siwa culture]]. One of the fragments was made of bloomery iron rather than meteoritic iron.<ref>Chen, Jianli, Mao, Ruilin, Wang, Hui, Chen, Honghai, Xie, Yan, Qian, Yaopeng, 2012. ''The iron objects unearthed from tombs of the Siwa culture in Mogou, Gansu, and the origin of iron-making technology in China.'' Wenwu (Cult. Relics) 8, 45–53 (in Chinese)</ref><ref name=ReferenceA>p. xl, Historical Dictionary of Ancient Greek Warfare, J, Woronoff & I. Spence</ref>

Other than this one exception, the earliest known iron artifacts made from bloomeries in China date to end of the 9th century BC.<ref name=Lam>{{cite book|author=Wengcheong Lam |title=Everything Old is New Again? Rethinking the Transition to Cast Iron Production in the Central Plains of China |year=2014|publisher=Chinese University of Hong Kong|page=519}}</ref> Cast iron was used in [[History of China#Ancient China|ancient China]] for warfare, agriculture and architecture.<ref name=Wagner/> Around 500 BC, metalworkers in the southern [[state of Wu]] achieved a temperature of 1130 °C. At this temperature, iron combines with 4.3% carbon and melts. The liquid iron can be [[casting|cast]] into [[molding (process)|molds]], a method far less laborious than individually forging each piece of iron from a bloom.

Cast iron is rather brittle and unsuitable for striking implements. It can be [[Decarburization|''decarburized'']] to steel or wrought iron by heating it in air for several days. In China, these iron working methods spread northward, and by 300 BC, iron was the material of choice throughout China for most tools and weapons.<ref name= "Wagner">{{cite book|author=Donald B. Wagner|title=Iron and Steel in Ancient China|year=1993|publisher=Brill|isbn=978-90-04-09632-5|page=408}}</ref> A mass grave in [[Hebei]] province, dated to the early 3rd century BC, contains several soldiers buried with their weapons and other equipment. The artifacts recovered from this grave are variously made of wrought iron, cast iron, malleabilized cast iron, and quench-hardened steel, with only a few, probably ornamental, bronze weapons.

[[File:Yuan Dynasty - waterwheels and smelting.png|thumb|260px|An illustration of furnace bellows operated by waterwheels, from the ''Nong Shu'', by [[Wang Zhen (official)|Wang Zhen]], 1313 AD, during the [[Yuan dynasty]] in China]]

During the [[Han dynasty]] (202 BC–220 AD), the government established ironworking as a state monopoly, [[Discourses on Salt and Iron|repealed during the latter half of the dynasty and returned to private entrepreneurship]], and built a series of large blast furnaces in [[Henan]] province, each capable of producing several tons of iron per day. By this time, Chinese metallurgists had discovered how to fine molten pig iron, stirring it in the open air until it lost its carbon and could be hammered (wrought). In modern Mandarin-[[Chinese language|Chinese]], this process is now called ''chao'', literally [[stir frying]]. Pig iron is known as 'raw iron', while wrought iron is known as 'cooked iron'. By the 1st century BC, Chinese metallurgists had found that wrought iron and cast iron could be melted together to yield an alloy of intermediate carbon content, that is, steel.<ref>Needham (1986). Vol. 4, Part 3, p. 197.</ref><ref>Needham (1986). Vol. 4, Part 3, p. 277.</ref><ref>Needham (1986). Vol. 4, Part 3, p. 563 g</ref>

According to legend, the sword of [[Liu Bang]], the first Han emperor, was made in this fashion. Some texts of the era mention "harmonizing the hard and the soft" in the context of ironworking; the phrase may refer to this process. The ancient city of Wan ([[Nanyang, Henan|Nanyang]]) from the Han period forward was a major center of the iron and steel industry.<ref>Needham (1986). Vol. 4, Part 3, p. 86.</ref> Along with their original methods of forging steel, the Chinese had also adopted the production methods of creating Wootz steel, an idea imported from India to China by the 5th century AD.<ref>Needham (1986). Vol. 4, Part 1, p. 282.</ref>

During the Han dynasty, the Chinese were also the first to apply [[hydraulic]] power (i.e. a [[waterwheel]]) in working the bellows of the blast furnace. This was recorded in the year 31 AD, as an innovation by the Chinese mechanical engineer and politician [[Du Shi]], [[Prefect]] of Nanyang.<ref>Needham (1986). Vol. 4, Part 2, p. 370.</ref> Although Du Shi was the first to apply water power to bellows in metallurgy, the first drawn and printed illustration of its operation with water power appeared in 1313 AD, in the Yuan dynasty era text called the ''Nong Shu''.<ref>Needham (1986). Vol. 4, Part 2, p. 371.</ref>

In the 11th century, there is evidence of the production of steel in [[Song dynasty|Song China]] using two techniques: a "berganesque" method that produced inferior, heterogeneous steel and a precursor to the modern Bessemer process that utilized partial decarbonization via repeated forging under a cold blast.<ref>{{cite journal |last= Hartwell |first= Robert |title= Markets, Technology and the Structure of Enterprise in the Development of the Eleventh Century Chinese Iron and Steel Industry |year= 1966 |journal= Journal of Economic History |volume= 26 |pages= 53–54 |doi= 10.1017/S0022050700061842 |s2cid= 154556274 }}</ref> By the 11th century, there was a large amount of deforestation in China due to the iron industry's demands for charcoal.<ref name=ebrey158>(2006). 158.</ref> By this time however, the Chinese had learned to use [[Coke (fuel)|bituminous coke]] to replace charcoal, and with this switch in resources many acres of prime timberland in China were spared.<ref name=ebrey158/>

{{See also|Early Japanese iron-working techniques|l1=Early Japanese Ironworking}}

===Iron Age Europe=== {{See also|Iron Age Europe|Bronze Age Europe}} [[File:Axe of iron from Swedish Iron Age, found at Gotland, Sweden.jpg|thumb|An [[axe]] made of iron, dating from the [[Iron Age Scandinavia|Swedish Iron Age]]|176x176px]]

The earliest iron objects found in Europe date from the 3rd millennium BC, and are assigned to the [[Yamnaya culture]] and [[Catacomb culture]].<ref name="Early Iron in Eastern Europe">{{cite web |url=https://www.topoi.org/project/a-5-6/ |website=topoi.org |title=Early Iron in Eastern Europe}}</ref><ref name=":2">{{cite book |last=Anthony |first=David |title=The Horse, the Wheel, and Language |date=2007 |publisher=Princeton University Press |isbn=978-0-691-05887-0 |pages=336 |quote=One unappreciated aspect of Early Bronze Age and Middle Bronze Age steppe metallurgy was its experimentation with iron. … A Catacomb-period grave at [[Gerasimovka, Belgorod Oblast|Gerasimovka]] on the Donets (western Russia/Ukraine), probably dated around 2500 BCE, contained a knife with a handle made of arsenical bronze and a blade made of iron. The iron did not contain magnetite or nickel, as would be expected in meteoric iron, so it is thought to have been forged. Iron objects were rare, but they were part of the experiments conducted by steppe metalsmiths during the Early and Middle Bronze Ages}}</ref> Eastern Europe, especially the Cis-Ural region, shows the highest concentration of early and middle Bronze Age iron objects in western Eurasia,<ref name="Early Iron in Eastern Europe"/> though most of these are thought to consist of meteoric Iron.<ref name=":3">{{cite journal |last1=Kašuba |first1=Maja |display-authors=etal |date=2019 |title=Eisenmetallurgie in der Bronzezeit Osteuropas. Die archäologischen Quellen und ihre Interpretation |url=https://www.academia.edu/71797205 |journal=Praehistorische Zeitschrift |volume=94 |issue=1 |pages=158–209 |doi=10.1515/pz-2019-0001}}</ref> A knife blade from the Catacomb culture dated to c. 2300 BC is thought to have been made from smelted iron.<ref name=":2" /><ref name=":3" /> During most of the Middle and Late [[Bronze Age Europe|Bronze Age]] in Central Europe, iron was present, though scarce. It was used for personal ornaments and small knives, for repairs on bronzes, and for bimetallic items.<ref>{{cite web |url=https://www.britannica.com/topic/history-of-Europe/The-Iron-Age |title=The Iron Age |website=Encyclopaedia Britannica}}</ref> Early smelted iron finds from central Europe include an iron knife or sickle from Ganovce in Slovakia, possibly dating from the 18th-15th century BC,<ref>{{cite book|url=https://www.academia.edu/39962973|last1=Hansen|first1=Svend|date=2019|editor-last1=Hansen|editor-first1=Svend|editor-last2=Krause|editor-first2=Rüdiger|title=Bronze Age Fortresses in Europe|publisher=Verlag Dr. Rudolf Habelt GmbH, Bonn|pages=204|chapter=The Hillfort of Teleac and Early Iron in Southern Europe}}</ref><ref>{{cite journal |url=https://www.degruyter.com/document/doi/10.1515/prhz.2000.75.2.153/html?lang=de&srsltid=AfmBOopr-4KCxgrUCIcatZ1CiRPKvXgtEnxp9mrIv0JmeLWnOVe86QZy |journal=Praehistorische Zeitschrift |volume=75 |date=2000 |title=Eine Eisensichel aus Gánovce. Zur Interpretation des ältesten Eisengegenstandes in Mitteleuropa |last1=Furmánek |first1=Václav |issue=2 |pages=153–160 |doi=10.1515/prhz.2000.75.2.153|url-access=subscription }}</ref> an iron ring from Vorwohlde in Germany dating from circa the 15th century BC,<ref>{{cite thesis|type=PhD|last=Turnbull|first=Anne|date=1984|title=From bronze to iron : The occurrence of iron in the British later Bronze Age|publisher=Edinburgh University|pages=24|s2cid=164098953 }}</ref> and an iron chisel from Heegermühle in Germany dating from circa 1000 BC.<ref>{{cite web |url=https://artsandculture.google.com/story/life-and-belief-during-the-bronze-age-neues-museum-staatliche-museen-zu-berlin/DAVRgpAwHmLsLw?hl=en |title=Life and Belief in the Bronze Age: Belt Disc from Heegermühle |website=Neues Museum}}</ref><ref>{{cite web |url=http://www.askanier-welten.de/ur-und-fruehgeschichte/der-depotfund-von-heegermuehle-bei-eberswalde/ |title=Der Depotfund von Heegermühle bei Eberswalde |website=askanier-welten.de}}</ref> Smelted iron objects are known from Eastern Europe dating from after 1200 BC.<ref name=":3" />

In the 11th century BC iron swords replaced bronze swords in Southern Europe, especially in Greece, and in the 10th century BC iron became the prevailing metal in use.<ref>{{cite book|url=https://www.academia.edu/39962973|last1=Hansen|first1=Svend|date=2019|editor-last1=Hansen|editor-first1=Svend|editor-last2=Krause|editor-first2=Rüdiger|title=Bronze Age Fortresses in Europe|publisher=Verlag Dr. Rudolf Habelt GmbH, Bonn|pages=204–206|chapter=The Hillfort of Teleac and Early Iron in Southern Europe}}</ref> In the [[Pannonian Basin|Carpathian Basin]] there is a significant increase in iron finds dating from the 10th century BC onwards, with some finds possibly dating as early as the 12th century BC.<ref name=":0">{{cite book|url=https://www.academia.edu/39962973|last1=Hansen|first1=Svend|date=2019|editor-last1=Hansen|editor-first1=Svend|editor-last2=Krause|editor-first2=Rüdiger|title=Bronze Age Fortresses in Europe|publisher=Verlag Dr. Rudolf Habelt GmbH, Bonn|pages=214|chapter=The Hillfort of Teleac and Early Iron in Southern Europe}}</ref> Iron swords have been found in central Europe dating from the 10th century BC; however, the Iron Age began in earnest with the [[Hallstatt culture]] from 800 BC.<ref>{{cite book|url=https://www.academia.edu/39962973|last1=Hansen|first1=Svend|date=2019|editor-last1=Hansen|editor-first1=Svend|editor-last2=Krause|editor-first2=Rüdiger|title=Bronze Age Fortresses in Europe|publisher=Verlag Dr. Rudolf Habelt GmbH, Bonn|pages=211|chapter=The Hillfort of Teleac and Early Iron in Southern Europe}}</ref> Steel was produced from circa 800 BC as part of the production of swords,<ref name=":4" /> and swords made entirely of high-carbon steel are known from pre-Roman period.<ref name=":5">{{cite journal |last1=Skóra |first1=Kalina |display-authors=etal |date=2019 |title=Weaponry of the Przeworsk Culture in the light of metallographic examinations. The case of the cemetery in Raczkowice |url=https://www.academia.edu/76153774 |journal=Praehistorische Zeitschrift |volume=94 |issue=2 |pages=454–498 |doi=10.1515/pz-2019-0016 |quote=In Pre-Roman Period Europe one can see a strong diversification of sword blade technologies. There are many low quality blades made from iron or low-carbon steel; on the other hand, one also encounters artefacts made partially or entirely from high-carbon steel.}}</ref> Evidence for iron metallurgy in Britain dates from the 10th century BC,<ref>{{cite journal |url=https://www.academia.edu/95081361 |journal=Proceedings of the Prehistoric Society |volume=72 |date=2006 |pages=367–421 |title=Ironworking in the Bronze Age? Evidence from a 10th Century BC Settlement at Hartshill Copse, Upper Bucklebury, West Berkshire |last1=COLLARD |first1=Mark |display-authors=etal |doi=10.1017/S0079497X0000089X}}</ref> with the beginning of the Iron Age dated to the 8th century BC.<ref>{{Cite book |last=Cunliffe |first=Barry W. |title=Iron Age Communities in Britain: An Account of England, Scotland and Wales from the Seventh Century BC Until the Roman Conquest |edition=4th|publisher=Routledge |year=2005 |isbn=0-415-34779-3 |author-link=Barry Cunliffe |pages=32}}</ref> The production of high-carbon steel is attested in Britain from circa 490 BC.<ref name=":6">{{Cite web |date=15 January 2014 |title=East Lothian's Broxmouth fort reveals edge of steel |url=https://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-25734877 |website=BBC News}}</ref> Iron metallurgy began to be practised in [[Iron Age Scandinavia|Scandinavia]] during the later [[Nordic Bronze Age|Bronze Age]] from at least the 9th century BC,<ref>{{cite journal |last1=Lund |first1=Julie |last2=Melheim |first2=Lene |date=2011 |title=Heads and Tails – Minds and Bodies: Reconsidering the Late Bronze Age Vestby Hoard |url=https://www.academia.edu/1285488 |journal=European Journal of Archaeology |volume=14 |issue=3 |pages=441–464 |doi=10.1179/146195711798356692 |quote=iron technology was practiced in the Nordic region from at least the ninth century BC (Hjärthner-Holdar 1993; Serning 1984)}}</ref> with evidence for steel production from 800–700 BC.<ref name=":1">{{cite journal |last1=Bennerhag |first1=Carina |display-authors=etal |date=2021 |title=Hunter-gatherer metallurgy in the Early Iron Age of Northern Fennoscandia |journal=Antiquity |volume=95 |issue=384 |pages=1511–1526 |doi=10.15184/aqy.2020.248 |doi-access=free}}</ref> Iron and steel artefacts, including high-carbon steel, were manufactured in northern Sweden, Finland and Norway (in the [[Cap of the North]]) from c. 200–50 BC.<ref name=":1" /> Evidence for iron metallurgy in Italy and Sardinia dates from the Late Bronze Age (c. 1350-950 BC).<ref>{{cite book |url=https://www.academia.edu/2061542 |title=Papers in Italian Archaeology VI, Vol. I |chapter=Metallurgy in Italy between the Late Bronze Age and the Early Iron Age: the Coming of Iron |publisher=Archaeopress |date=2005 |pages=491–505 |last=Giardino |first=Claudio}}</ref><ref>{{cite book |url=https://www.ancientportsantiques.com/wp-content/uploads/Documents/PLACES/Corsica-Sardinia/Sardinia-LoSchiavo2005.pdf |title=Archaeometallurgy in Sardinia |chapter=The First Iron in Sardinia |pages=401–406 |publisher=Editions Monique Mergoil |isbn=2-907303-89-9 |last=Lo Schiavo |first=Fulvio |date=2005}}</ref> High-carbon steel tools were produced in Iberia (Portugal) from c. 900 BC.<ref>{{cite web |date=2023 |title=Steel was being used in Europe 2900 years ago |url=https://www.sciencedaily.com/releases/2023/02/230228154510.htm |website=sciencedaily.com}}</ref><ref>{{cite web |title=Stone-working and the earliest steel in Iberia: Scientific analyses and experimental replications of final bronze age stelae and tools (Gonzalez et al. 2023) |doi=10.1016/j.jas.2023.105742 |url=https://www.sciencedirect.com/science/article/abs/pii/S0305440323000201}}</ref>

From 500 BC the [[La Tène culture]] saw a significant increase in iron production, with iron metallurgy also becoming common in southern Scandinavia. The spread of ironworking in Central and Western Europe is associated with [[Celts|Celtic]] expansion.<ref name=":4">{{cite book |last1=Wells |first1=Peter |url=https://books.google.com/books?id=vkV8bcgLbiAC&q=the+celtic+world |title=The Celtic World |date=1995 |publisher=Routledge |isbn=9781135632434 |editor-last=Green |editor-first=Miranda |pages=218 |chapter=Resources and Industry}}</ref> By the 1st century BC, [[Noric steel]] was famous for its quality and sought after by the [[Roman military]].<ref>{{cite journal |url=https://www.academia.edu/80083255 |journal=Steel Research International |volume=76 |issue=9 |date=2005 |title=Norican Steel - An Assessment of the Archaeological Finds at the Magdalensberg Site, Carinthia, Compared to the "Celtic Trove" of Gründberg Hill, Linz |last1=Presslinger |first1=Hubert |display-authors=etal |pages=666–671 |doi=10.1002/srin.200506073 }}</ref> The annual output of iron in the [[Roman Empire]] is estimated at 84,750 [[tonne]]s.<ref>Craddock, Paul T. (2008): "Mining and Metallurgy", in: [[John Peter Oleson|Oleson, John Peter]] (ed.): ''The Oxford Handbook of Engineering and Technology in the Classical World'', Oxford University Press, {{ISBN|978-0-19-518731-1}}, p. 108</ref>

The production of ultrahigh carbon steel is attested at the [[Germanic peoples|Germanic]] site of [[Heeten]] in the [[Netherlands]] from the 2nd to 4th/5th centuries AD, in the [[Roman Iron Age|Late Roman Iron Age]].<ref>{{cite journal |last1=Godfrey |first1=Evelyne |last2=van Nie |first2=Matthijs |date=2004 |title=A Germanic ultrahigh carbon steel punch of the Late Roman-Iron Age |url=https://www.sciencedirect.com/science/article/abs/pii/S0305440304000202 |journal=Journal of Archaeological Science |volume=31 |issue=8 |pages=1117–1125 |doi=10.1016/j.jas.2004.02.002|bibcode=2004JArSc..31.1117G |url-access=subscription }}</ref>

===Sub-Saharan Africa=== {{Main|Iron metallurgy in Africa}} [[File:African bloomery furnace types.png|thumb|Examples of African bloomery furnace types]]

[[Archaeometallurgical]] [[History of science and technology in Africa|scientific knowledge and technological development]] originated in numerous centers of Africa; the centers of origin were located in [[West Africa]], [[Central Africa]], and [[East Africa]]; consequently, as these origin centers are located within inner Africa, these archaeometallurgical developments are thus native African technologies.<ref name="Bandama">{{cite journal |last1=Bandama |first1=Foreman |last2=Babalola |first2=Abidemi Babatunde |title=Science, Not Black Magic: Metal and Glass Production in Africa |journal=African Archaeological Review |date=13 September 2023 |volume=40 |issue=3 |pages=531–543 |doi=10.1007/s10437-023-09545-6 |doi-access=free |issn=0263-0338 |oclc=10004759980 |s2cid=261858183}}</ref> Iron metallurgical development occurred 2631 BCE – 2458 BCE at Lejja, in Nigeria, 2136 BCE – 1921 BCE at Obui, in Central Africa Republic, 1895 BCE – 1370 BCE at Tchire Ouma 147, in Niger, and 1297 BCE – 1051 BCE at Dekpassanware, in Togo.<ref name="Bandama" />

Though there is some uncertainty, some archaeologists believe that iron metallurgy was developed independently in sub-Saharan Africa (possibly in West Africa).<ref name=Eggert51>Eggert (2014). pp. [https://books.google.com/books?id=BBn1BQAAQBAJ&pg=PA51 51]–59.</ref><ref name=Holl2009>{{cite journal |last=Holl |first= Augustin F. C. |title= Early West African Metallurgies: New Data and Old Orthodoxy |journal= Journal of World Prehistory |date=6 November 2009 |volume=22 |issue=4 |pages=415–438 |doi=10.1007/s10963-009-9030-6 |s2cid= 161611760}}</ref>

Inhabitants of Termit, in eastern [[Niger]], smelted iron around 1500 BC.<ref>[http://portal.unesco.org/en/ev.php-URL_ID=3432&URL_DO=DO_TOPIC&URL_SECTION=201.html Iron in Africa: Revisiting the History] {{webarchive|url=https://web.archive.org/web/20081025192915/http://portal.unesco.org/en/ev.php-URL_ID%3D3432%26URL_DO%3DDO_TOPIC%26URL_SECTION%3D201.html |date=2008-10-25 }} – Unesco (2002)</ref>

In the region of the [[Aïr Mountains]] in [[Niger]] there are also signs of independent copper smelting between 2500 and 1500 BC. The process was not in a developed state, indicating smelting was not foreign. It became mature about 1500 BC.<ref>Ehret, Christopher (2002). ''The Civilizations of Africa''. Charlottesville: University of Virginia, pp. 136, 137 {{ISBN|0-8139-2085-X}}.</ref>

Archaeological sites containing iron smelting furnaces and slag have also been excavated at sites in the [[Nsukka]] region of southeast [[Nigeria]] in what is now [[Igbo people|Igboland]]: dating to 2000 BC at the site of [[Lejja]] (Eze-Uzomaka 2009)<ref name=Eze-Uzomaka>{{cite journal|last1=Eze–Uzomaka|first1=Pamela|title=Iron and its influence on the prehistoric site of Lejja|url=https://www.academia.edu/4103707|website=Academia.edu|publisher=University of Nigeria, Nsukka, Nigeria|access-date=12 December 2014}}</ref><ref name=Holl2009/> and to 750 BC and at the site of [[Opi (archaeological site)|Opi]] (Holl 2009).<ref name=Holl2009/> The site of Gbabiri (in the Central African Republic) has yielded evidence of iron metallurgy, from a reduction furnace and blacksmith workshop; with earliest dates of 896–773 BC and 907–796 BC respectively.<ref name=Eggert53>Eggert (2014). pp. [https://books.google.com/books?id=BBn1BQAAQBAJ&pg=PA53 53]–54.</ref> Similarly, smelting in bloomery-type furnaces appear in the [[Nok culture]] of central Nigeria by about 550 BC and possibly a few centuries earlier.<ref name=miller/><ref name=Stuiver/><ref>Tylecote (1975) (see below)</ref>{{dubious|This seems to be a 1975 (1st?) ed., never mentioned elsewhere.|date= February 2022}}<ref name=Eggert51/><ref name=Eggert53/>

There is also evidence that [[carbon steel]] was made in Western [[Tanzania]] by the ancestors of the [[Haya people]] as early as 2,300 to 2,000 years ago (about 300 BC or soon after) by a complex process of "pre-heating" allowing temperatures inside a furnace to reach 1300 to 1400 °C.<ref name=SchmidtCS>{{Cite journal |last1=Schmidt |first1=Peter |last2=Avery |first2=Donald |date=1978 |title=Complex Iron Smelting and Prehistoric Culture in Tanzania |journal=Science |volume=201 |issue=4361 |pages=1085–1089 |jstor=1746308 |doi=10.1126/science.201.4361.1085 |pmid=17830304 |bibcode=1978Sci...201.1085S |s2cid=37926350}}</ref><ref name=Schmidt1983>{{Cite journal |last1=Schmidt |first1=Peter |last2=Avery |first2=Donald |date=1983 |title=More Evidence for an Advanced Prehistoric Iron Technology in Africa |journal=Journal of Field Archaeology |volume=10 |issue=4 |pages=421–434 |doi=10.1179/009346983791504228}}</ref><ref name=SchmidtHA>{{Cite book |last=Schmidt |first=Peter |title=Historical Archaeology: A Structural Approach in an African Culture |publisher=Greenwood Press |year=1978 |location=Westport, CT}}</ref><ref>{{Cite book |title=The Culture and Technology of African Iron Production |last1=Avery |first1=Donald |last2=Schmidt |first2=Peter |publisher=University of Florida Press |year=1996 |location=Gainesville |pages=267–276 |chapter=Preheating: Practice or illusion}}</ref><ref>{{Cite book |title=A Companion to African History |last=Schmidt |first=Peter |publisher=Wiley Blackwell |year=2019 |editor-last=Worger |editor-first=W |location=Hoboken, NJ |pages=267–288 |chapter=Science in Africa: A history of ingenuity and invention in African iron technology |editor-last2=Ambler |editor-first2=C |editor-last3=Achebe |editor-first3=N}}</ref><ref>{{Cite book |title=The Culture and Technology of African Iron Production |last=Childs |first=S. Terry |publisher=University of Florida Press |year=1996 |editor-last=Schmidt |editor-first=P. |location=Gainesville, FL |chapter=Technological history and culture in western Tanzania}}</ref>

Iron and copper working spread southward through the continent, reaching the [[Cape of Good Hope|Cape]] around AD 200.<ref name=miller/><ref name=Stuiver/> The widespread use of iron revolutionized the [[Bantu languages|Bantu]]-speaking farming communities who adopted it, driving out and absorbing the rock tool using hunter-gatherer societies they encountered as they expanded to farm wider areas of [[savanna]]. The technologically superior Bantu-speakers spread across southern Africa and became wealthy and powerful, producing iron for tools and weapons in large, industrial quantities.<ref name=miller /><ref name=Stuiver/>

The earliest records of bloomery-type furnaces in [[East Africa]] are discoveries of smelted iron and carbon in [[Nubia]] that date back between the 7th and 6th centuries BC,<ref>{{cite book|url=https://books.google.com/books?id=PZcX2jQFTRcC&pg=PA61|title=A History of Sub-Saharan Africa|first1=Robert O.|last1=Collins|first2=James M.|last2=Burns|year=2007|publisher=Cambridge University Press|via=Google Books|isbn=978-0521867467}}</ref><ref>{{cite book|url=https://books.google.com/books?id=6tsaBtp0WrMC&pg=PA173|title=The Nubian Past: An Archaeology of the Sudan|first=David N.|last=Edwards|year=2004|publisher=Taylor & Francis|via=Google Books|isbn=978-0203482766}}</ref><ref name=Humphris>{{cite journal |vauthors= Humphris J, Charlton MF, Keen J, Sauder L, Alshishani F |title= Iron Smelting in Sudan: Experimental Archaeology at The Royal City of Meroe |journal= Journal of Field Archaeology |volume= 43 |issue=5 |pages= 399–416 |date= June 2018 |doi= 10.1080/00934690.2018.1479085 |doi-access= free}}</ref> particularly in [[Meroe]] where there are known to have been ancient bloomeries that produced metal tools for the Nubians and Kushites and produced surplus for their economy.

[[File:Typical bloomery iron production operational sequence.webp|thumb|Typical bloomery iron production operational sequence starting with acquiring raw materials through smelting and smithing]]

===Medieval Islamic world=== Iron technology was further advanced by several [[inventions in medieval Islam]], during the [[Islamic Golden Age]]. By the 11th century, every province throughout the [[Muslim world]] had industrial mills in operation, from [[Al-Andalus|Islamic Spain]] and [[North Africa]] in the west to the [[Middle East]] and [[Central Asia]] in the east.{{Sfn|Lucas|2005|p=10–11, 27}} There are also 10th-century references to [[cast iron]], as well as archeological evidence of [[blast furnace]]s being used in the [[Ayyubid]] and [[Mamluk]] empires from the 11th century, thus suggesting a diffusion of Chinese metal technology to the Islamic world.<ref>{{cite journal|title=Ahmad Y. Al-Hassan and Donald R. Hill, 'Islamic technology: an illustrated history'|author=R. L. Miller|journal=Medical History|volume=32|issue=4|date=October 1988|pages=466–467|doi=10.1017/s0025727300048602|doi-access=free}}</ref>

One of the most famous steels produced in the medieval Near East was [[Damascus steel]] used for [[swordmaking]], and mostly produced in [[Damascus]], [[Syria]], in the period from 900 to 1750. This was produced using the [[crucible steel]] method, based on the earlier Indian [[wootz steel]]. This process was adopted in the Middle East using locally produced steels. The exact process remains unknown, but it allowed [[carbide]]s to precipitate out as micro particles arranged in sheets or bands within the body of a blade. Carbides are far harder than the surrounding low carbon steel, so swordsmiths could produce an edge that cut hard materials with the precipitated carbides, while the bands of softer steel let the sword as a whole remain tough and flexible. A team of researchers based at the [[Technische Universität Dresden|Technical University]] of [[Dresden]] that uses [[X-ray]]s and [[electron microscopy]] to examine Damascus steel discovered the presence of [[cementite]] [[nanowires]]<ref>{{cite journal |first=W. |last=Kochmann |author2=Reibold M. |author3=Goldberg R. |author4=Hauffe W. |author5=Levin A. A. |author6=Meyer D. C. |author7=Stephan T. |author8=Müller H. |author9=Belger A. |author10=Paufler P. |year=2004 |title=Nanowires in ancient Damascus steel |journal=Journal of Alloys and Compounds |volume=372 |issue=1–2 |pages=L15–L19 |issn=0925-8388 |doi=10.1016/j.jallcom.2003.10.005 }}<br />{{cite journal |first=A. A. |last=Levin |author2=Meyer D. C. |author3=Reibold M. |author4=Kochmann W. |author5=Pätzke N. |author6=Paufler P. |year=2005 |title=Microstructure of a genuine Damascus sabre |journal=Crystal Research and Technology |volume=40 |issue=9 |pages=905–916 |doi=10.1002/crat.200410456 |bibcode=2005CryRT..40..905L |s2cid=96560374 |url=http://www.crystalresearch.com/crt/ab40/905_a.pdf |url-status=live |archive-url=https://web.archive.org/web/20070809235447/http://www.crystalresearch.com/crt/ab40/905_a.pdf |archive-date=2007-08-09 }}</ref> and [[carbon nanotube]]s.<ref>{{cite journal |first=M. |last=Reibold |author2=Levin A. A. |author3=Kochmann W. |author4=Pätzke N. |author5=Meyer D. C. |date=16 November 2006 |title=Materials:Carbon nanotubes in an ancient Damascus sabre |journal=Nature |volume=444 |page=286 |doi=10.1038/444286a |pmid=17108950 |issue=7117 |bibcode=2006Natur.444..286R|s2cid=4431079 |doi-access=free }}</ref> Peter Paufler, a member of the Dresden team, says that these nanostructures give Damascus steel its distinctive properties<ref name=jmrefs>{{cite web|url=http://news.nationalgeographic.com/news/2006/11/061116-nanotech-swords.html|title=Legendary Swords' Sharpness, Strength From Nanotubes, Study Says|website=news.nationalgeographic.com|url-status=dead|archive-url=https://web.archive.org/web/20160128192641/http://news.nationalgeographic.com/news/2006/11/061116-nanotech-swords.html|archive-date=2016-01-28}}</ref> and are a result of the [[forging]] process.<ref name=jmrefs/><ref name=sword/>

==Medieval and early modern Europe== There was no fundamental change in the technology of iron production in Europe for many centuries. European metal workers continued to produce iron in bloomeries. However, the [[Medieval]] period brought two developments—the use of water power in the bloomery process in various places (outlined above), and the first European production in cast iron.

===Powered bloomeries=== {{Main|Bloomery}} Sometime in the medieval period, water power was applied to the bloomery process. It is possible that this was at the [[Cistercian]] Abbey of [[Clairvaux Abbey|Clairvaux]] as early as 1135, but it was certainly in use in early 13th century [[France]] and Sweden.{{Sfn|Lucas|2005|p=19}} In [[England]], the first clear documentary evidence for this is the accounts of a forge of the [[Bishop of Durham]], near [[Bedburn]] in 1408,<ref>Tylecote (1992). p. 76.</ref> but that was certainly not the first such ironworks. In the [[Furness]] district of England, powered bloomeries were in use into the beginning of the 18th century, and near [[Garstang]] until about 1770.

The Catalan Forge was a variety of powered bloomery. Bloomeries with [[hot blast]] were used in upstate [[New York State|New York]] in the mid-19th century.

===Blast furnace=== {{Main|Blast furnace}} [[File:Iron-Making.jpg|thumb|upright=1.5|Ironmaking described in "[[The Popular Encyclopedia; or, Conversations Lexicon|The Popular Encyclopedia]]" vol. VII, published 1894]]

The preferred method of iron production in Europe until the development of the [[puddling (metallurgy)|puddling process]] in 1783–84. Cast iron development lagged in Europe because wrought iron was the desired product and the intermediate step of producing cast iron involved an expensive blast furnace and further refining of pig iron to cast iron, which then required a labor and capital intensive conversion to wrought iron.<ref name="Tylecote"/>

Through a good portion of the Middle Ages, in Western Europe, iron was still being made by the working of iron blooms into wrought iron. Some of the earliest casting of iron in Europe occurred in Sweden, in two sites, [[Lapphyttan]] and Vinarhyttan, between 1150 and 1350. Some scholars have speculated the practice followed the [[Mongol]]s across [[Russia]] to these sites, but there is no clear proof of this hypothesis, and it would certainly not explain the pre-Mongol datings of many of these iron-production centres. In any event, by the late 14th century, a market for cast iron goods began to form, as a demand developed for cast iron cannonballs.

===Finery forge=== {{Main|Finery forge}} An alternative method of [[decarburization|decarburising]] [[pig iron]] was the [[finery forge]], which seems to have been devised in the region around [[Namur (city)|Namur]] in the 15th century. By the end of that century, this [[Walloon process]] spread to the ''Pay de Bray'' on the eastern boundary of [[Normandy]], and then to England, where it became the main method of making wrought iron by 1600. It was introduced to Sweden by [[Louis De Geer (1587–1652)|Louis de Geer]] in the early 17th century and was used to make the [[oregrounds iron]] favoured by English steelmakers.

A variation on this was the [[Finery forge#German forge|German forge]]. This became the main method of producing [[bar iron]] in Sweden.

===Cementation process=== {{Main|Cementation process}} In the early 17th century, ironworkers in [[Western Europe]] had developed the [[cementation process]] for [[carburization|carburizing]] [[wrought iron]]. Wrought iron bars and charcoal were packed into stone boxes, then sealed with clay to be held at a red heat continually tended in an oxygen-free state immersed in nearly pure carbon (charcoal) for up to a week. During this time, carbon diffused into the surface layers of the iron, producing ''cement steel'' or ''blister steel''—also known as case hardened, where the portions wrapped in iron (the pick or axe blade) became harder, than say an axe hammer-head or shaft socket which might be insulated by clay to keep them from the carbon source. The earliest place where this process was used in England was at [[Coalbrookdale]] from 1619, where Sir Basil Brooke had two cementation furnaces (recently excavated in 2001–2005<ref>Belford and Ross, Paper: [https://www.academia.edu/175895/English_steelmaking_in_the_seventeenth_century_the_excavation_of_two_cementation_furnaces_at_Coalbrookdale English steelmaking in the seventeenth century: the excavation of two cementation furnaces at Coalbrookdale] {{webarchive|url=https://web.archive.org/web/20180510201753/http://www.academia.edu/175895/English_steelmaking_in_the_seventeenth_century_the_excavation_of_two_cementation_furnaces_at_Coalbrookdale |date=2018-05-10 }}, Academia.edu, accessdate=30 March 2017</ref>). For a time in the 1610s, he owned a patent on the process, but had to surrender this in 1619. He probably used [[Forest of Dean]] iron as his raw material, but it was soon found that oregrounds iron was more suitable. The quality of the steel could be improved by [[faggoting (metalworking)|faggoting]], producing the so-called shear steel.

===Crucible steel=== In the 1740s, [[Benjamin Huntsman]] found a means of melting blister steel, made by the cementation process, in crucibles. The resulting [[crucible steel]], usually cast in ingots, was more homogeneous than blister steel.<ref name=Tylecote>Tylecote (1992).</ref>{{rp|145}}

==Transition to coke in England== {{Further|Industrial Revolution#Iron industry}}

===Beginnings=== Early iron smelting used charcoal as both the heat source and the reducing agent. By the 18th century, the availability of wood for making charcoal was limiting the expansion of iron production, so that England became increasingly dependent for a considerable part of the iron required by its industry, on Sweden (from the mid-17th century) and then from about 1725 also on Russia.{{citation needed|date=January 2015}} Smelting with coal (or its derivative [[coke (fuel)|coke]]) was a long sought objective. The production of pig iron with coke was probably achieved by [[Dud Dudley]] around 1619,<ref name=EB1911>{{cite EB1911 |wstitle=Iron and Steel |volume=14 |page=803 |first=Henry Marion |last=Howe |author-link=Henry Marion Howe}}</ref> and with a mixed fuel made from coal and wood again in the 1670s. However this was probably only a technological rather than a commercial success. [[Shadrach Fox]] may have smelted iron with coke at Coalbrookdale in [[Shropshire]] in the 1690s, but only to make cannonballs and other cast iron products such as shells. However, in the peace after the [[Nine Years War]], there was no demand for these.<ref>{{cite journal |last= King |first= P. W. |title= Dud Dudley's contribution to metallurgy |year= 2002 |journal= Historical Metallurgy |volume= 36 |issue=1 |pages= 43–53}}</ref><ref>{{cite journal |last= King |first= P. W. |year= 2001 |title= Sir Clement Clerke and the adoption of coal in metallurgy |journal= Trans. Newcomen Soc. |volume= 73 |issue= 1 |pages= 33–52 |doi= 10.1179/tns.2001.002 |s2cid= 112533187}}</ref>

===Abraham Darby and his successors=== {{Main|Abraham Darby I}} In 1707, [[Abraham Darby I]] patented a method of making cast iron pots. His pots were thinner and hence cheaper than those of his rivals. Needing a larger supply of pig iron he leased the blast furnace at Coalbrookdale in 1709. There, he made iron using coke, thus establishing the first successful business in Europe to do so. His products were all of cast iron, though his immediate successors attempted (with little commercial success) to fine this to bar iron.<ref>A. Raistrick, ''A dynasty of Ironfounders'' (1953; 1989); N. Cox, 'Imagination and innovation of an industrial pioneer: The first Abraham Darby' ''Industrial Archaeology Review'' 12(2) (1990), 127–144.</ref>

[[Wrought iron|Bar iron]] thus continued normally to be made with charcoal pig iron until the mid-1750s. In 1755 [[Abraham Darby II]] (with partners) opened a new coke-using furnace at [[Horsehay]] in Shropshire, and this was followed by others. These supplied coke pig iron to finery forges of the traditional kind for the production of [[wrought iron|bar iron]]. The reason for the delay remains controversial.<ref>A. Raistrick, ''Dynasty''; C. K. Hyde, ''Technological change and the British iron industry 1700–1870'' (Princeton, 1977), 37–41; P. W. King, 'The Iron Trade in England and Wales 1500–1815' (Ph.D. thesis, Wolverhampton University, 2003), 128–141.</ref>

===New forge processes=== [[File:Puddling furnace.jpg|thumb|Schematic drawing of a puddling furnace]]

It was only after this that economically viable means of converting pig iron to bar iron began to be devised. A process known as [[potting and stamping]] was devised in the 1760s and improved in the 1770s, and seems to have been widely adopted in the [[West Midlands (region)|West Midlands]] from about 1785. However, this was largely replaced by [[Henry Cort]]'s puddling process, patented in 1784, but probably only made to work with grey pig iron in about 1790. These processes permitted the great expansion in the production of iron that constitutes the Industrial Revolution for the iron industry.<ref>G. R. Morton and N. Mutton, 'The transition to Cort's puddling process' ''Journal of Iron and Steel Institute'' 205(7) (1967), 722–728; R. A. Mott (ed. P. Singer), ''Henry Cort: The great finer: creator of puddled iron'' (1983); P. W. King, 'Iron Trade', 185–193.</ref>

In the early 19th century, Hall discovered that the addition of iron oxide to the charge of the puddling furnace caused a violent reaction, in which the pig iron was [[decarburization|decarburised]], this became known as 'wet puddling'. It was also found possible to produce steel by stopping the [[puddling (metallurgy)|puddling process]] before decarburisation was complete.

==Hot blast== {{Main|Hot blast}}

The efficiency of the blast furnace was improved by the change to [[hot blast]], patented by [[James Beaumont Neilson]] in Scotland in 1828.<ref name=EB1911/> This further reduced production costs. Within a few decades, the practice was to have a 'stove' as large as the furnace next to it into which the waste gas (containing CO) from the furnace was directed and burnt. The resultant heat was used to preheat the air blown into the furnace.<ref>A. Birch, ''Economic History of the British Iron and Steel Industry'', 181–189; C. K. Hyde, ''Technological Change and the British iron industry'' (Princeton 1977), 146–159.</ref>

==Industrial steelmaking== {{Main|Steelmaking}} [[File:Bessemer converter.jpg|thumb|right|Schematic drawing of a Bessemer converter]]

Apart from some production of [[puddled steel]], English steel continued to be made by the cementation process, sometimes followed by remelting to produce crucible steel. These were batch-based processes whose raw material was bar iron, particularly Swedish oregrounds iron.

The problem of mass-producing cheap steel was solved in 1855 by Henry Bessemer, with the introduction of the [[Bessemer process|Bessemer converter]] at his steelworks in [[Sheffield]], England. (An early converter can still be seen at the city's [[Kelham Island Museum]]). In the Bessemer process, molten pig iron from the blast furnace was charged into a large crucible, and then air was blown through the molten iron from below, igniting the dissolved carbon from the coke. As the carbon burned off, the melting point of the mixture increased, but the heat from the burning carbon provided the extra energy needed to keep the mixture molten. After the carbon content in the melt had dropped to the desired level, the air draft was cut off: a typical Bessemer converter could convert a 25-ton batch of pig iron to steel in half an hour.

In the 1860s development of regenerative furnaces and higher temperature refractory lining allowed to melt steel in an [[open hearth]]. That was slow and energy intensive, but allowed to better control the chemical makeup of the product and recycle iron scrap.

The acidic refractory lining of Bessemer converters and early open hearths didn't allow to remove phosphorus from steel with lime, which prolonged the life of puddling furnaces in order to utilize phosphorous iron ores abundant in Continental Europe. However, in the 1870s [[Gilchrist–Thomas process]] was developed, and later basic lining was adopted for the open hearths as well.

Finally, the [[Basic oxygen steelmaking|basic oxygen process]] was introduced at the Voest-Alpine works in 1952; a modification of the basic Bessemer process, it lances oxygen from above the steel (instead of bubbling air from below), reducing the amount of nitrogen uptake into the steel. The basic oxygen process is used in all modern steelworks; the last Bessemer converter in the U.S. was retired in 1968. Furthermore, the last three decades have seen a massive increase in the mini-mill business, where scrap steel only is melted with an [[electric arc furnace]]. These mills only produced bar products at first, but have since expanded into flat and heavy products, once the exclusive domain of the integrated steelworks.

Until these 19th-century developments, steel was an expensive commodity and only used for a limited number of purposes where a particularly hard or flexible metal was needed, as in the cutting edges of tools and springs. The widespread availability of inexpensive steel powered the [[Second Industrial Revolution]] and modern society as we know it. Mild steel ultimately replaced wrought iron for almost all purposes, and wrought iron is no longer commercially produced. With minor exceptions, alloy steels only began to be made in the late 19th century. [[Stainless steel]] was developed on the eve of [[World War I]] and was not widely used until the 1920s.

==Modern steel industry== {{See also|History of the steel industry (1850–1970)|History of the steel industry (1970–present)|Global steel industry trends|Steel production by country|List of steel producers}} [[File:Steel production by country map 2023.png|thumb|upright=2.3|Steel production (in million tons) by country in 2023]] The steel industry is often considered an indicator of economic progress, because of the critical role played by steel in infrastructural and overall [[economic development]].<ref>{{cite web|title = Steel Industry|url = http://bx.businessweek.com/steel-industry/|access-date = 2009-07-12|url-status=dead|archive-url = https://web.archive.org/web/20090618230340/http://bx.businessweek.com/steel-industry/|archive-date = 2009-06-18}}</ref> In 1980, there were more than 500,000 U.S. steelworkers. By 2000, the number of steelworkers had fallen to 224,000.<ref>"''[https://books.google.com/books?id=iOgfSDKecCcC&pg=PA4557 Congressional Record V. 148, Pt. 4, April 11, 2002 to April 24, 2002]''". [[United States Government Printing Office]].</ref>

The [[boom and bust|economic boom]] in China and India caused a massive increase in the demand for steel. Between 2000 and 2005, world steel demand increased by 6%. Since 2000, several Indian<ref>{{cite web |author= Chopra, Anuj |title= India's steel industry steps onto world stage |work= Cristian Science Monitor |date=12 February 2007 |url= http://csmonitor.com/2007/0212/p07s02-wosc.html |access-date= 2009-07-12}}</ref> and Chinese steel firms have risen to prominence,{{according to whom|date=October 2016}} such as [[Tata Steel]] (which bought [[Corus Group]] in 2007), [[Baosteel Group]] and [[Shagang Group]]. {{As of|2017}}, though, [[ArcelorMittal]] is the world's [[List of steel producers|largest steel producer]].<ref>{{cite web|url=https://www.worldsteel.org/en/dam/jcr:1a0978ce-d387-4ce9-8d1b-5f929f343ac1/2017_2016+top+steel+producers_Extended+list.pdf|publisher=World Steel Association|title=Top Steelmakers in 2017|access-date=August 22, 2018|archive-url=https://web.archive.org/web/20180823005844/https://www.worldsteel.org/en/dam/jcr:1a0978ce-d387-4ce9-8d1b-5f929f343ac1/2017_2016+top+steel+producers_Extended+list.pdf|archive-date=August 23, 2018|url-status=dead}}</ref> In 2005, the [[British Geological Survey]] stated China was the top steel producer with about one-third of the world share; Japan, Russia, and the US followed respectively.<ref>{{cite web |title=Long-term planning needed to meet steel demand |work=The News |date=2008-03-01 |url=http://www.hellenicshippingnews.com/index.php?option=com_content&task=view&id=1576&Itemid=46 |access-date=2010-11-02 |archive-url=https://archive.today/20240525020105/https://www.webcitation.org/5twr3Sstf?url=http://www.hellenicshippingnews.com/index.php%3Foption=com_content&task=view&id=1576&Itemid=46 |archive-date=2024-05-25 |url-status=dead }}</ref>

The large production capacity of steel results in a significant amount of carbon dioxide emissions inherent related to the main production route. In 2019, it was estimated that 7 to 9% of the global carbon dioxide emissions resulted from the steel industry.<ref>{{Cite journal|date=2019-12-01|title=Carbon capture and utilization in the steel industry: challenges and opportunities for chemical engineering|url=https://biblio.ugent.be/publication/8635595/file/01H8XFTKEF30019BF0QCCJDKB9.pdf|journal=Current Opinion in Chemical Engineering|language=en|volume=26|pages=81–87|doi=10.1016/j.coche.2019.09.001|issn=2211-3398|last1=De Ras|first1=Kevin|last2=Van De Vijver|first2=Ruben|last3=Galvita|first3=Vladimir V.|last4=Marin|first4=Guy B.|last5=Van Geem|first5=Kevin M.|bibcode=2019COCE...26...81D |hdl=1854/LU-8635595 |s2cid=210619173}}</ref> Reduction of these emissions are expected to come from a shift in the main production route using cokes, more recycling of steel and the application of carbon capture and storage or carbon capture and utilization technology.<ref>{{Cite journal|title=Retrofitting Blast Furnaces for Producing Green Steel and Green Urea|url=https://www.ijee.latticescipub.com/wp-content/uploads/papers/v5i2/B187105021125.pdf |journal=Indian Journal of Environment Engineering|language=en|volume=5|pages=19–25|doi=10.54105/ijee.B1871.05021125|issn= 2582-9289|last1=Nallapaneni|first1=Sasidhar|date=2025 |issue=2 |access-date=21 November 2025}}</ref>

In 2008, steel began [[commodity market|trading as a commodity]] on the [[London Metal Exchange]]. At the end of 2008, the steel industry faced a sharp downturn that led to many cut-backs.<ref>{{cite news|url=https://www.nytimes.com/2009/01/02/business/02steel.html?_r=1&partner=permalink&exprod=permalink|title=Steel Industry, in Slump, Looks to Federal Stimulus|last=Uchitelle|first=Louis|date=2009-01-01|newspaper=The New York Times|access-date=2009-07-19|author-link=Louis Uchitelle}}</ref>

==See also== * [[Bintie]], a type of refined iron * [[Steel#History|History of steelmaking]] * [[Iron Age]] * [[List of alloys]] * [[Nok culture]] * [[Non-ferrous extractive metallurgy]] * [[Roman metallurgy]]

==Citations== {{Reflist|2}}

==Bibliography== {{refbegin}} * Ebrey, Walthall, Palais (2006). ''East Asia: A Cultural, Social, and Political History''. Boston: Houghton Mifflin Company.{{ISBN?}} * {{Cite book |last=Eggert |first=Manfred |title=Nok: African Sculpture in Archaeological Context |chapter= Early iron in West and Central Africa |publisher=Africa Magna Verlag Press |year= 2014 |editor-last= Breunig |editor-first=P |location= Frankfurt |isbn= 978-3937248462 |url= https://books.google.com/books?id=BBn1BQAAQBAJ |access-date= 21 February 2022}} * {{cite journal |last= Lucas |first= Adam Robert |year= 2005 |title= Industrial Milling in the Ancient and Medieval Worlds: A Survey of the Evidence for an Industrial Revolution in Medieval Europe |journal= Technology and Culture |volume= 46 |issue=1 |pages= 1–30 |doi=10.1353/tech.2005.0026 |s2cid= 109564224}} * Needham, Joseph (1986). ''Science and Civilization in China: Volume 4, Part 2''; Needham, Joseph (1986). ''Science and Civilization in China: Volume 4, Part 3''. * {{cite book |last= Tylecote |first=R. F. |title= A History of Metallurgy |edition=2nd |year= 1992 |publisher= Maney Publishing, for the Institute of Materials |location= London |isbn= 978-0901462886}} * {{cite book |last= Waldbaum |first= Jane C. |title= From Bronze to Iron: The Transition from the Bronze Age to the Iron Age in the Eastern Mediterranean |publisher= Paul Åström |location=[[Gothenburg]] |series= Studies in Mediterranean Archaeology, vol. LIV |year= 1978 |isbn= 9185058793}} {{refend}}

==Further reading== * Knowles, Anne Kelly. (2013). ''Mastering Iron: The Struggle to Modernize an American Industry, 1800–1868'' (University of Chicago Press) 334 pages {{ISBN?}} * Lam, Wengcheong (2014). ''Everything Old is New Again? Rethinking the transition to Cast Iron Production in the Plains of Central China'', Chinese University of Hong Kong {{ISBN?}} * Pleiner, R. (2000). ''Iron in Archaeology. The European Bloomery Smelters'', Praha, Archeologický Ústav Av Cr. {{ISBN?}} * Pounds, Norman J. G. (1957). "Historical Geography of the Iron and Steel Industry of France". ''Annals of the Association of American Geographers'' 47#1, pp. 3–14. {{JSTOR|2561556}}. * Wagner, Donald (1996). ''Iron and Steel in Ancient China''. Leiden: E.J. Brill. {{ISBN?}} * Woods, Michael and Mary B. Woods (2000). ''Ancient Construction (Ancient Technology)'' Runestone Press {{ISBN?}}

==External links== * {{Cite NIE|wstitle=Iron and Steel, Metallurgy of|short=x}}

[[Category:4th-millennium BC establishments]] [[Category:History of metallurgy]] [[Category:Steelmaking]]