Wootz steel: Difference between revisions

'''Wootz steel''', also known as '''Seric steel''', is a [[crucible steel]] characterized by a pattern of bands and high carbon content. These bands are formed by sheets of microscopic [[carbide]]s within a tempered [[martensite]] or [[pearlite]] matrix in higher-[[carbon steel]], or by [[Allotropes of iron|ferrite]] and pearlite banding in lower-carbon steels. It was a pioneering [[steel alloy]] developed in [[southern India]] in the mid-1st millennium BC and exported globally.<ref name=":0">{{Cite journal|last=J.‐S-S. Park K. Rajan R. Ramesh|title=High‐carbonHigh-carbon steel and ancient sword‐makingsword-making as observed in a double‐edgeddouble-edged sword from an Iron Age megalithic burial in Tamil Nadu, India|journal=[[Archaeometry (journal)|Archaeometry]]|year=2020|volume=62|pages=68–80|doi=10.1111/arcm.12503|doi-access=free}}</ref>

Wootz steel originated in the mid-1st millennium BCBCE in India, in present-day [[Tiruchirappalli]], [[Kodumanal]], [[Erode]], [[Tamil Nadu]].<ref name=":0" /> There are several ancient Tamil, North Indian, Greek, Chinese and Roman literary references to high-carbon Tamil steel.{{citation needed|date=June 2021}} In later times{{when|date=June 2021}}, wootz steel was also made in [[Golconda]] in [[Telangana]], [[Karnataka]] and Sri Lanka.<ref>{{cite journal |first=Sharada |last=Srinivasan |date=15 November 1994 |title=Wootz crucible steel: a newly discovered production site in India |journal=Papers from the Institute of Archaeology |volume=5 |pages=49–59 |doi=10.5334/pia.60|doi-access=free }}</ref><ref>{{Cite journal |last1=Wijepala |first1=W. M. T. B. |last2=Young |first2=Sansfica M. |last3=Ishiga |first3=Hiroaki |date=2022-04-01 |title=Reading the archaeometallurgical findings of Yodhawewa site, Sri Lanka: contextualizing with South Asian metal history |url=https://doi.org/10.1007/s41826-022-00046-0 |journal=Asian Archaeology |language=en |volume=5 |issue=1 |pages=21–39 |doi=10.1007/s41826-022-00046-0 |s2cid=247355036 |issn=2520-8101}}</ref><ref>{{cite book |first=Herbert Henery |last=Coghlan |year=1977 |title=Notes on prehistoric and early iron in the Old World |pages=99–100 |edition=2nd |publisher=[[Pitt Rivers Museum]]}}</ref><ref>{{cite journal |first=B. |last=Sasisekharan |year=1999 |url=http://www.new1.dli.ernet.in/data1/upload/insa/INSA_1/20005b66_263.pdf |title=Technology of Iron and Steel in Kodumanal |journal=[[Indian Journal of History of Science]] |volume=34 |number=4 |archive-url=https://web.archive.org/web/20150724033115/http://www.new1.dli.ernet.in/data1/upload/insa/INSA_1/20005b66_263.pdf |archive-date=24 July 2015}}</ref> The steel was exported as cakes of steely iron that came to be known as "Wootzwootz".<ref name="Davidson20">{{cite book |last=Davidson |first=Hilda Roderick Ellis |title=The Sword in Anglo-Saxon England: Its Archaeology and Literature |url=https://books.google.com/books?id=nY0T9n4zAQAC&pg=PA20 |date=1998 |publisher=Boydell & Brewer |isbn=978-0-85115-716-0 |page=20}}</ref> The method was to heat black [[magnetite]] ore in the presence of carbon in a sealed clay crucible inside a charcoal furnace to completely remove [[slag]]. An alternative was to smelt the ore first to give [[wrought iron]], then heat and hammer it to remove slag. The carbon source was bamboo and leaves from plants such as [[Senna auriculata|Avārai]].<ref name="Davidson20"/><ref name="Burton111">{{cite book |last=Burton |first=Sir Richard Francis |author-link=Richard Francis Burton |title=The Book of the Sword |year=1884 |publisher=Chatto & Windus |location=London |page=111 |url=https://archive.org/stream/booksword00unkngoog#page/n152/mode/2up}}</ref> Locals in Sri Lanka adopted the production methods of creating wootz steel from the Chera Tamils[[Cheras]] by the 5th century BC.<ref name="Manning365">{{cite book |last=Manning |first=Charlotte Speir |title=Ancient and Medieval India |volume=2 |url=https://books.google.com/books?id=nmESJR3a0RYC&pg=PA365 |isbn=978-0-543-92943-3 |page=365}}</ref> Joseph Needham in 1971 claimed China produced a similar steel also by the 5th century BCE<ref name="Needham282">{{cite book |title=Science and Civilisation in China: Volume 4, Physics and Physical Technology |date=1 April 1971 |first=Joseph |last=Needham |author-link=Joseph Needham |page=282 |publisher=[[Cambridge University Press]] |isbn=978-0-52107-060-7}}</ref> but more recent research in China (2009) showed that wootz like steel ingots was mentioned for the first time much later, during the [[Northern Wei|Bei Wei Dynasty]] (386-534 CE) under the name “Bintie” or “Pin t’ieh”, said ingots were initally given by Persian Kings as valuable presents and only started to be produced in China during the [[Tang Dynasty]] (618-907 CE) and possibly even by [[Khitans]] during the [[Liao Dynasty]] (916–1125 CE).<ref >{{cite book |title=BINTIE: THE WOOTZ STEEL IN ANCIENT CHINA from ''Indian Journal of History of Science, 44.3'' |date= 2009 |first=William |last=Lox |page=369 to 388}}https://www.tf.uni-kiel.de/matwis/amat/iss/kap_a/articles/wootz_in_china.pdf</ref> In Sri Lanka, this early steel-making method employed a unique wind furnace, driven by the monsoon winds. Production sites from antiquity have emerged, in places such as [[Anuradhapura]], [[Tissamaharama]] and [[Samanalawewa]], as well as imported artifacts of ancient iron and steel from Kodumanal. Recent archaeological excavations (2018) of the Yodhawewa site (in [[Mannar District|Mannar]] District) discovered a lower half-spherical furnace,  crucible fragments, and lid fragments related to the crucible steel production through the carburization process.<ref>{{Cite journal |last1=Wijepala |first1=W. M. T. B. |last2=Young |first2=Sansfica M. |last3=Ishiga |first3=Hiroaki |date=2022-04-01 |title=Reading the archaeometallurgical findings of Yodhawewa site, Sri Lanka: contextualizing with South Asian metal history |url=https://doi.org/10.1007/s41826-022-00046-0 |journal=Asian Archaeology |language=en |volume=5 |issue=1 |pages=21–39 |doi=10.1007/s41826-022-00046-0 |s2cid=247355036 |issn=2520-8101}}</ref> A [[Tissamaharama Tamil Brahmi inscription|200 BC Tamil trade guild in Tissamaharama]], inIn the South East of Sri Lanka, broughtthere with themwere some of the oldest iron and steel artifacts and production processes to the island from the [[classical antiquity|classical period]].<ref>''Hobbies'' (April 1963) Vol. 68, No.5, p.45, Chicago: [[Lightner Publishing Company]].</ref><ref name="Mahathevan">{{cite news |url=http://www.thehindu.com/opinion/op-ed/An-epigraphic-perspective-on-the-antiquity-of-Tamil/article16265606.ece |title=An epigraphic perspective on the antiquity of Tamil |last=Mahathevan |first=Iravatham |date=24 June 2010 |newspaper=[[The Hindu]] |publisher=The Hindu Group |access-date=31 October 2010}}</ref><ref name="Ragupathy">{{cite news |url=http://www.tamilnet.com/art.html?catid=79&artid=32303 |title=Tissamaharama potsherd evidences ordinary early Tamils among population |last=Ragupathy |first=P. |date=28 June 2010 |work=Tamilnet |access-date=31 October 2010}}</ref><ref>{{cite journal |url=http://www.archaeology.lk/wp-content/uploads/2011/02/Dinithi-Volume-1-Issue-4.pdf |date=February 2012 |title=Dinithi |volume=1 |issue=4 |journal=Sri Lanka Archaeology }}{{Dead link|date=November 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Trade between India and Sri Lanka through the [[Arabian Sea]] introduced wootz steel to Arabia. The term ''muhannad'' مهند or ''hendeyy'' هندي in pre-Islamic and early Islamic Arabic refers to sword blades made from Indian steel, which were highly prized, and are attested in [[Arabic poetry]]. Further trade spread the technology to the city of [[Damascus]], where an industry developed for making weapons of this steel. This led to the development of [[Damascus steel]]. The 12th century Arab traveler [[Muhammad al-Idrisi|Edrisi]] mentioned the "Hinduwani" or Indian steel as the best in the world.<ref name="SR_IISc">{{cite journal |first1=Sharada |last1=Srinivasan |first2=Srinivasa |last2=Ranganathan |title=India's Legendary Wootz Steel: An Advanced Material of the Ancient World |url=http://materials.iisc.ernet.in/~wootz/heritage/WOOTZ.htm |year=2004 |journal=[[Iron & Steel Heritage of India]] |pages=69–82 |oclc=82439861}}</ref> Arab accounts also point to the fame of 'Teling' steel, which can be taken to refer to the region of [[Telangana]]. The [[Golkonda|Golconda]] region of Telangana clearly being the nodal centrecenter for the export of wootz steel to West Asia.<ref name="SR_IISc"/>

From the 17th century onwards, several European travelers observed the steel manufacturing in South India, at [[Mysore]], [[Malabar region|Malabar]] and [[Golconda]]. The word "wootz" appears to have originated as a mistranscription of ''wook''Sanskrit terms; the [[Tamil languageSanskrit]] root word for the alloy is ''urukkuutsa''.<ref name="GirijaJan2002">{{cite book|url=https://books.google.com/books?id=n4vtAAAAMAAJ|title=Tradition and innovation in the history of iron making: an Indo-European perspective|last1=Pande|first1=Girija|last2=af Geijerstam|first2=Jan|publisher=Pahar Parikarma|year=2002|isbn=978-81-86246-19-1|page=45}}</ref> Another{{Which|date=November 2021}}theory says that the word is a variation of ''uchcha'' or ''ucha''{{dubious|date=November 2021}} ("superior"). According to one theory, the word ''ukku'' is based on the meaning "melt, dissolve". Other [[Dravidian languages]] have similar-sounding words for steel: ''ukku'' in [[Kannada language|Kannada]]<ref name="RoddamSrini2003">{{cite book|url=https://books.google.com/books?id=XpFxcweodqQC&pg=PA135|title=The Dynamics of Technology: Creation and Diffusion of Skills and Knowledge|last1=Narasimha|first1=Roddam|last2=Srinivasan|first2=J.|last3=Biswas|first3=S. K.|date=2003|publisher=SAGE Publications|isbn=978-0-7619-9670-5|page=135}}</ref><ref>[[Michael Faraday]], as quoted by {{cite book|title=The Philosopher's Tree|last=Day|first=Peter|date=1999-01-01|publisher=Institute of Physics Publishing|isbn=978-0-7503-0571-6|location=Bristol, UK|page=108}}</ref> and [[Telugu language|Telugu]], and ''urukku'' in [[Malayalam]]. When [[Benjamin Heyne]] inspected the Indian steel in [[Ceded Districts]] and other Kannada-speaking areas, he was informed that the steel was ''ucha kabbina'' ("superior iron"), also known as ''ukku tundu'' in Mysore.<ref name="Edward1885">{{cite book |first=Edward |last=Balfour |title=The Cyclopædia of India and of Eastern and Southern Asia, Commercial Industrial, and Scientific: Products of the Mineral, Vegetable, and Animal Kingdoms, Useful Arts and Manufactures |url=https://archive.org/details/cyclopindiaeast03balfuoft |year=1885 |publisher=Bernard Quaritch |page=[https://archive.org/details/cyclopindiaeast03balfuoft/page/1092 1092]}}</ref><ref name="Jeans1880">{{cite book |first=James Stephen |last=Jeans |title=Steel: Its History, Manufacture, Properties and Uses |url=https://books.google.com/books?id=tOZZAAAAYAAJ&pg=PA294 |year=1880 |publisher=E. & F.N. Spon |page=294}}</ref>

The distinct patterns of Wootzwootz steel that can be made through forging are wave, ladder, and rose patterns with finely spaced bands. However, with hammering, dyeing, and [[etching]] further customized patterns were made.<ref>{{Cite book|last=Durand-Charre|first=Madeleine|url=https://books.google.com/books?id=n9pRE-4W8XIC&q=wootz&pg=PA21|title=Microstructure of Steels and Cast Irons|date=2004 |publisher=Springer |isbn=978-3-540-20963-8 }}</ref>

The presence of [[cementite]] [[nanowires]] and carbon nanotubes has been identified by Peter Pepler of [[TU Dresden]] in the microstructure of wootz steel.<ref>{{cite journal |url=http://www.nature.com/news/2006/061113/full/news061113-11.html |title=Sharpest cut from nanotube sword |first=Katharine |last=Sanderson |date=15 November 2006 |journal=[[Nature (journal)|Nature]] |doi=10.1038/news061113-11|s2cid=136774602 |doi-access=free }}</ref> There is a possibility of an abundance of ultrahard metallic carbides in the steel matrix precipitating out in bands. Wootz swords were renowned for their sharpness and [[toughness]].

Wootz steel was analyzed by [[Michael Faraday]] and recorded to contain 0.01-0.07% [[aluminium]]. Faraday, Messrs (et al.), and Stodart hypothesized that aluminium was needed in the steel and was important in forming the excellent properties of wootz steel. However T. H. Henry deduced that presence of aluminium in the Wootzwootz used by these studies was due to [[slag]], forming as silicates. Percy later reiterated that the quality of wootz steel does not depend on the presence of aluminium.<ref>{{Cite book|last=Percy|first=John|url=https://archive.org/details/metallurgyartex02percgoog|page=[https://archive.org/details/metallurgyartex02percgoog/page/n204 183]|title=Metallurgy: The Art of Extracting Metals from Their Ores, and Adapting Them to Various Purposes of Manufacture|date=1864|publisher=[[John Murray (publishing house)|J. Murray]]|language=en}}</ref>

Russian metallurgist [[Pavel Petrovich Anosov]] (see [[Bulat steel]]) was almost able to reproduce ancient Wootzwootz steel with nearly all of its properties and the steel he created was very similar to traditional Wootzwootz.{{Cn|date=August 2024}} He documented four different methods of producing Wootzwootz steel that exhibited traditional patterns.{{Cn|date=August 2024}} He died before he could fully document and publish his research. Oleg Sherby and Jeff Wadsworth and [[Lawrence Livermore National Laboratory]] have all done research, attempting to create steels with characteristics similar to Wootzwootz, but without success.{{Cn|date=August 2024}} J.D Verhoeven and Alfred Pendray reconstructed methods of production, proved the role of impurities of ore in the pattern creation, and reproduced Wootzwootz steel with patterns microscopically and visually identical to one of the ancient blade patterns.{{Cn|date=August 2024}} Reibold et al.'s analyses spoke of the presence of carbon nanotubes enclosing nanowires of cementite, with the trace elements/impurities of [[vanadium]], [[molybdenum]], [[chromium]] etc. contributing to their creation, in cycles of heating/cooling/forging. This resulted in a hard high carbon steel that remained malleable<ref>{{cite bookconference |title=Discovery of Nanotubes in Ancient Damascus Steel |workbook-title=Physics and Engineering of New Materials |volume=127 |pages=305–310 |date= 2009 |doi=10.1007/978-3-540-88201-5_35 | last1 = Reibold | first1 = Marianne | last2 = Paufler | first2 = Peter | last3 = Levin | first3 = Aleksandr A. | last4 = Kochmann | first4 = Werner | last5 = Pätzke | first5 = Nora | last6 = Meyer | first6 = Dirk C.|series=[[Springer Proceedings in Physics]] |publisher=[[Springer Science+Business Media|Springer]] |bibcode=2009penm.book..305R |isbn=978-3-540-88200-8 }}</ref>

There are smiths who are now consistently producing Wootzwootz steel blades visually identical to the old patterns.<ref>{{cite journal |first1=Oleg |last1=Sherby |first2=Jeffrey |last2=Wadsworth |title=Ancient blacksmiths, the Iron Age, Damascus steels, and modem metallurgy |url=https://www.researchgate.net/figure/222563386_fig2_Fig-7-Two-Damascus-swords-and-surface-markings |journal=Journal of Materials Processing Technology |volume=117 |number=3 |pages=347–353 |date=23 November 2001 |doi=10.1016/S0924-0136(01)00794-4}}</ref> Steel manufactured in [[Kutch district|Kutch]] particularly enjoyed a widespread reputation, similar to those manufactured at [[Glasgow]] and [[Sheffield]].<ref name="Manning365" />

Wootz was made over nearly a 2,000-year period (the oldest sword samples date to around 200 ADCE){{Cn|date=August 2024}} and the methods of production of ingots, the ingredients, and the methods of forging varied from one area to the next. Some Wootzwootz blades displayed a pattern, while some did not.{{Cn|date=August 2024}} Heat treating was quite different from forging, and there were many different patterns whichthat were created by the various smiths who spanned from China to Scandinavia.{{citation needed|date=March 2020}}