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Damascus steel

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For Damascus Twist barrels, see Skelp.
For the album of the same name, see Damascus Steel (album).
Close-up of a 16th century Iranian crucible forged Damascus steel sword

Damascus steel was a term used by several Western cultures from the Medieval period onward to describe a type of steel used in swordmaking from about 300 BC to 1700 AD. These swords are characterized by distinctive patterns of banding and mottling reminiscent of flowing water. Such blades were reputed to be not only tough and resistant to shattering, but capable of being honed to a sharp and resilient edge.[1]

The original method of producing Damascus steel is not known. Due to differences in raw materials and manufacturing techniques, modern attempts to duplicate the metal have failed. Today, the term is used to describe steel that mimics the appearance and performance of Damascus steel, usually that which is produced by the techniques of crucible forging or pattern welding.

The reputation and history of Damascus steel has given rise to many legends, such as the ability to cut through a rifle barrel, or cut a hair falling across the blade.[2] No evidence exists to support such claims. But National Geographic and others have reported on research revealing nanowires and carbon nanotubes (which was the first time this had been seen in steel). Whatever the lost methods of making Damascus steel, of ore refinement and forging, they accidentally harnessed impurities and changes at the molecular level. Although modern steel still outperforms these swords, the microscopic chemical reactions may have made the blades more resilient for their time. Other experts are unsurprised, and expect to discover such nanotubes in more and more relics as they are looked at more closely.[3][4]

Etymology

Several theories on the origins of the term "Damascus steel" exists, but none of them may be confirmed definitively.[5] Damascus may refer to:

  • The swords forged in Damascus. For instance, al-Kindi, refers to swords made in Damascus as Damascene. This word has often been employed as an epithet in Eastern European legends (Sabya Damaskinya or Sablja Dimiskija meaning "Damascene saber"), including the Serbian and Bulgarian legends of Prince Marko, a historical figure of the late 14th century in what is currently the Republic of Macedonia.
  • The swords sold in Damascus. [6]
  • The name of the swordsmith. For instance, the author al-Beruni refers to swords made by a man he names Damashqi.
  • The comparison of the patterns found on the swords to Damask fabrics woven in the Byzantine empire.[6]

History

Historians such as Hobson, Sinopoli, and Juleff state that the material used to produce the original damascus was ingots of Wootz steel, which originated in India and Sri Lanka[7] and later spread to Persia.[8] From the 3rd century to the 17th century, India was shipping steel ingots to the Middle East for use in Damascus steel.[9]

In Europe, research has demonstrated that high quality swords with damask patterns were produced by various pattern welding techniques since at least the 3rd century BC by the Celts and Germanic peoples.[10]

Close-up of a modern pattern welded damascus sheath knife

Loss of the technique

The process was lost to metalsmiths after production of the patterned swords gradually declined and eventually ceased circa 1750. Several modern theories have ventured to explain this decline, including the breakdown of trade routes to supply the needed metals, the lack of trace impurities in the metals, the possible loss of knowledge on the crafting techniques through secrecy and lack of transmission, or a combination of all the above.[11][12][13]

The raw material for producing the original Damascus steel is believed to be wootz imported from India.[11][12] Due to the distance of trade for this raw material, a sufficiently lengthy disruption of the trade routes could have ended the production of Damascus steel and eventually led to the loss of the technique. As well, the need for key trace impurities of tungsten or vanadium within the materials needed for production of the steel may be absent if this material was acquired from different production regions or smelted from ores lacking these key trace elements.[11] The technique for controlled thermal cycling after the initial forging at a specific temperature could also have been lost, thereby preventing the final damask pattern in the steel from occurring.[11][12]

The discovery of carbon nanotubes in the Damascus steel's composition supports this hypothesis, since the precipitation of carbon nanotubes likely resulted from a specific process that may be difficult to replicate should the production technique or raw materials used be significantly altered.[13] If this is true, Damascus swords, once manufactured, underwent a process of testing, and the small percentage that possessed the qualifications of Damascus swords were selected for delivery.

Reproduction attempts

Since pattern welding was a prominent technique used for swords and knives, and produced surface patterns similar to those found on Damascus blades, a belief existed that Damascus blades were made using a pattern welding technique. Pattern-welded steel has been sold currently as "Damascus steel", even though research suggests the original Damascus steel was created with a different technique. Pattern-welded Damascus is made from several[specify] types of steel and iron slices, which are then welded together to form a billet. The patterns vary depending on how the smith works the billet. The billet is drawn out and folded until the desired number of layers are formed. The belief that Damascus steel was pattern welded was challenged in the 1990s when J. D. Verhoeven and A. H. Pendray published an article on their experiments on reproducing the elemental, structural, and visual characteristics of Damascus steel.[11]

The Russian bulat steel contains many similar properties, albeit they are achieved by a different process. Experimental archaeology is a means by which Damascus steel has been attempted to be recreated. A different technique was proposed by Wadsworth and Sherby.

Verhoeven and Pendray started with a cake of steel that matched the properties of the original wootz steel from India, which also matched a number of original Damascus swords to which Verhoeven and Pendray had access. The wootz was in a soft, annealed state, with a grain structure and beads of pure iron carbide which were the result of the hypereutectoid state of the wootz. Verhoeven and Pendray had already determined that the grains on the surface of the steel were grains of iron carbide, so their question was how to reproduce the iron carbide patterns they saw in the Damascus blades from the grains in the wootz.

Although such material could be worked at low temperatures to produce the striated Damascene pattern of intermixed ferrite and cementite bands in a manner identical to pattern-welded Damascus steel, any heat treatment sufficient to dissolve the carbides would destroy the pattern permanently. However, Verhoeven and Pendray discovered that in samples of true Damascus steel, the Damascene pattern could be recovered by aging at a moderate temperature. Their investigations found that certain carbide forming elements, one of which was vanadium, did not disperse until higher temperatures than those needed to dissolve the carbides. Therefore, though a high heat treatment could remove the visual evidence of patterning associated with carbides, it did not remove the underlying patterning of the carbide forming elements; a subsequent lower temperature heat treatment, at a temperature at which the carbides were again stable, could recover the structure by the binding of carbon by those elements.

Modern methods

Two types of modern forged steel has patterning and physical properties resembling the original Damascus steel:

  • Forged crucible steel: Ingots consisting of high carbon steel with added metallic impurities are created by melting and allowing them to slowly cool and crystallize in its crucible. The resulting ingots are then slowly forged at "red heat" until the desired shape is achieved.
  • Pattern welded steel: Steels pieces of different carbon content are welded together with the aid of flux and continually bent, twisted, and forged until the piece is solid and its steel grain is of correct form and dimensions.

Most modern steels intended to mimic the appearance of original Damascus are a lamination of folded steels selected with cosmetic qualities, with grinding and polishing specifically to expose the layers. A limited amount of steel makers attempt to recreate the original Damascus steel by using ingots produced through wootz methods.

Several steelmaking techniques, other than the original wootz steel (such as Damascened steel and sometimes watered steel), can result in patterned surfaces, though not for the same reasons, and have been sold as Damascus steel. Historically authentic Damascus steel is processed from wootz steel or equivalent. A technique currently used for producing a similar material in appearance is pattern welding, which is widely used for custom knife making.[6] Modern materials intended to mimic the appearance of Damascus steel are usually made by pattern welding two tool steels, one with high nickel content, appearing bright, the other appearing more grey so that alternating steels produce light-dark stripes. Treating or pickling the steel with dilute acid after polishing enhances the pattern by darkening one of the steels more than the other. Folding and twisting while hammer forging the steel controls the striped pattern, and the method used is often trademarked. Experienced bladesmiths can manipulate the layered patterns to mimic the designs found in the surface of the medieval Damascus steel.

Celtic sword with Damascene pattern

One explanation of the legendary properties of the original is that the pattern consists of alternating bands of harder, brittle iron carbide or cementite and softer, more flexible iron. Another possibility is that the steel contains a small quantity of vanadium, which would theoretically strengthen the blade.[14] Original Damascus steel billet was formed from a small disk that was folded and forged by a hammer into its final shape. Unlike northern European methods, the ferro-smelting technique in Iran during the Middle Ages involved crucibles with a lid, baked in an oven similar to that used for bread.

Carbon nanotubes and nanowires were found in a sample of a 17th century sword forged from Damascus steel. The process of forging and annealing is thought to have accounted for the nano-scale structures.[15]

Manufacture

A team of researchers based at the Technical University of Dresden that used x-rays and electron microscopy to examine Damascus steel discovered the presence of cementite nanowires[16] and carbon nanotubes.[17] Peter Paufler, a member of the Dresden team, says that these nanostructures are a result of the forging process.[15][18]

Lefever Grade G shotgun with Pattern welded "Damascened steel" Barrels

Prior to the early 20th century, all shotgun barrels were forged by heating narrow strips of iron and steel and shaping them around a mandrel.[19][20] This process was referred to as "laminating" or "Damascus" and these barrels were found on shotguns that sold for $12.[19][20] These types of barrels earned a reputation for weakness and were never meant to be used with modern smokeless powder, as well as any kind of moderately powerful explosive.[20] Because of the appearance to Damascus steel, higher-end barrels were made by Belgian and British gun makers.[19][20] These barrels are proof marked and meant to be used with light pressure loads.[19] Current gun manufacturers such as Caspian Arms make slide assemblies and small parts such as triggers and safeties for Colt M1911 pistols from powdered Swedish steel resulting in a swirling two-toned effect; these parts are often referred to as "Stainless Damascus".[21]

See also

References

  1. ^ Figiel, Leo S. (1991). On Damascus Steel. pp. 10–11. ISBN 9780962871108. {{cite book}}: Unknown parameter |Publisher= ignored (|publisher= suggested) (help)
  2. ^ Becker, Otto Matthew (1910). High-speed steel: the development, nature, treatment, and use of high-speed steels, together with some suggestions as to the problems involved in their use. New York. pp. 10–14. {{cite book}}: Unknown parameter |Publisher= ignored (|publisher= suggested) (help)CS1 maint: location missing publisher (link)
  3. ^ http://archaeology.about.com/od/ancientweapons/a/damascus_steel_2.htm which itself cites various sources
  4. ^ http://news.nationalgeographic.com/news/2006/11/061116-nanotech-swords.html
  5. ^ Williams, Alan R. (2003). The knight and the blast furnace: a history of the metallurgy of armour in the Middle Ages & the early modern period Volume 12 of History of warfare. pp. 10–14. ISBN 9789004124981. {{cite book}}: Unknown parameter |Publisher= ignored (|publisher= suggested) (help)
  6. ^ a b c Goddard, Wayne (2000). The Wonder of Knifemaking. Krause. pp. 107–120. ISBN 9780873417983. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  7. ^ G. Juleff (1996). "An ancient wind powered iron smelting technology in Sri Lanka". Nature. 379: 60. doi:10.1038/379060a0.
  8. ^ Hobson, John M. (2004). The Eastern Origins of Western Civilisation. Cambridge University Press. p. 85. ISBN 0521547245.
  9. ^ Sinopoli, Carla M. (2003). The Political Economy of Craft Production: Crafting Empire in South India, c. 1350–1650. Cambridge University Press. p. 192. ISBN 0521826136.
  10. ^ Stefan Mäder: "Stähle, Steine und Schlangen. Zur Kultur- und Technikgeschichte von Schwertklingen des frühen Mittelalters", dissertation, Berlin 2001, pp. 275-282
  11. ^ a b c d e J. D. Verhoeven, A. H. Pendray, and W. E. Dauksch (1998). "The key role of impurities in ancient damascus steel blades". Journal of Mettalurgy. 50: 58.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  12. ^ a b c J. Wadsworth and O. D. Sherby (1980). "On the Bulat — Damascus steel revisited". Prog. Materials Science. 68: 25.
  13. ^ a b Lionel Milgrom (2009). "Carbon nanotubes: Saladin's secret weapon".
  14. ^ Talmadge, Joe. Knife Steel FAQ zknives.com. October 2005. Retrieved on 2010-07-11.
  15. ^ a b K. Sanderson (2006). "Sharpest cut from nanotube sword". Nature. 444: 286. doi:10.1038/news061113-11.
  16. ^ Kochmann, W. (2004). "Nanowires in ancient Damascus steel". Journal of Alloys and Compounds. 372: L15–L19. doi:10.1016/j.jallcom.2003.10.005. ISSN 0925-8388. {{cite journal}}: Cite has empty unknown parameter: |quotes= (help)
    Levin, A. A.; Meyer, D. C.; Reibold, M.; Kochmann, W.; Pätzke, N.; Paufler, P. (2005). "Microstructure of a genuine Damascus sabre" (PDF). Crystal Research and Technology. 40 (9): 905–916. doi:10.1002/crat.200410456.
  17. ^ Reibold, M.; Paufler, P; Levin, AA; Kochmann, W; Pätzke, N; Meyer, DC (November 16, 2006). "Materials:Carbon nanotubes in an ancient Damascus sabre". Nature. 444 (7117): 286. doi:10.1038/444286a. PMID 17108950.
  18. ^ Legendary Swords' Sharpness, Strength From Nanotubes, Study Says
  19. ^ a b c d Simpson, Layne (2003). Shotguns & Shotgunning. Krause Publications. p. 256. ISBN 978-0873495677. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  20. ^ a b c d Matunas, Edward A. (2003). Do-It-Yourself Gun Repair. Woods N' Water Inc. p. 240. ISBN 978-0972280426. {{cite book}}: Cite has empty unknown parameter: |coauthors= (help)
  21. ^ Hopkins, Cameron (2000). "Damascus Knight .45". American Handgunner Magazine. 20 (4): 128. {{cite journal}}: Cite has empty unknown parameter: |coauthors= (help)

Further reading

  • Eric M. Taleff, Bruce L. Bramfitt, Chol K. Syn, Donald R. Lesuer, Jeffrey Wadsworth, and Oleg D. Sherby, "Processing, structure, and properties of a rolled ultrahigh-carbon steel plate exhibiting a damask pattern," Materials Characterization 46 (1), 11-18 (2001).
  • J. D. Verhoeven, "A review of microsegregation induced banding phenomena in steels", J. Materials Engineering and Performance 9 (3), 286-296 (2000).

External links

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