Wootz steel is a steel characterized by a pattern of bands or sheets of micro carbides within a tempered martensite or pearlite matrix. It is the pioneering steel alloy matrix developed in South India in the sixth century BC and exported globally. It was also known in the ancient world as Seric Iron.
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History[edit]
The Wootz steel originated in South India and Sri Lanka.[1][2] There are several ancient Tamil, Greek, Chinese and Roman literary references to high carbon Indian steel since the time ofAlexander's India campaign. The crucible steel production process started in the sixth century BC, at production sites of Kodumanal in Tamil Nadu, Golconda in Andhra Pradesh, Karnatakaand Sri Lanka and exported globally; the Tamils of the Chera Dynasty producing what was termed the finest steel in the world, i.e. Seric Iron to the Romans, Egyptians, Chinese and Arabs by 500 BC.[3][4][5] The steel was exported as cakes of steely iron that came to be known as "Wootz."[6]
The Tamilakam method was to heat black magnetite ore in the presence of carbon in a sealed clay crucible inside a charcoal furnace. An alternative was to smelt the ore first to give wrought iron, then heated and hammered to be rid of slag. The carbon source was bamboo and leaves from plants such as Avārai.[7][8] The Chinese and locals in Sri Lanka adopted the production methods of creating Wootz steel from the Chera Tamils by the 5th century BC.[9][10] In Sri Lanka, this early steel-making method employed a unique wind furnace, driven by the monsoon winds, capable of producing high-carbon steel and 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. A 200 BC Tamil trade guild in Tissamaharama, in the South East of Sri Lanka, brought with them some of the oldest iron and steel artifacts and production processes to the island from the classical period.[11][12][13][14] The Arabs introduced the South Indian/Sri Lankan wootz steel to Damascus, where an industry developed for making weapons of this steel. The 12th century Arab traveler Edrisi mentioned the "Hinduwani" or Indian steel as the best in the world.[1] Another sign of its reputation is seen in a Persian phrase – to give an "Indian answer", meaning "a cut with an Indian sword."[15] Wootz steel was widely exported and traded throughout ancient Europe and the Arab world, and became particularly famous in the Middle East.[15]
Development of modern metallurgy[edit]
From the 17th century onwards, several European travelers observed the steel manufacturing in South India, at Mysore, Malabar and Golconda. The word "wootz" appears to have originated as a mistranscription of wook, an anglicised version of ukku, the word for steel in Kannada language.[16][17] According to one theory, the word ukku is based on the meaning "melt, dissolve"; other Dravidian languages have similar sounding words for steel, derived from the Tamil language root word for the alloy, urukku.[18] Another theory says that the word is a variation of uchcha or ucha ("superior"). 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.[19][20]
Legends of wootz steel and Damascus swords aroused the curiosity of the European scientific community from the 17th to the 19th Century. The use of high carbon alloys was not known in Europe previously and thus the research into wootz steel played an important role in the development of modern English, French and Russian metallurgy.[21]
In 1790, samples of wootz steel were received by Sir Joseph Banks, President of the British Royal society, sent by Helenus Scott. These samples were subjected to scientific examination and analysis by several experts.[22][23][24]
Specimens of daggers and other weapons were sent by the Rajahs of India to the International Exhibition of 1851 and 1862. Though the arms of the swords were beautifully decorated and jeweled, they were most highly prized for the quality of their steel. The swords of the Sikhs were said to bear bending and crumpling, and yet be fine and sharp.[15]
Characteristics[edit]
Wootz is characterized by a pattern caused by bands of clustered Fe
3C particles made of microsegregation of low levels of carbide-forming elements.[25] There is a possibility of an abundance of ultrahard metallic carbides in the steel matrix precipitating out in bands. Wootz swords, especially Damascus blades, were renowned for their sharpness and toughness.
3C particles made of microsegregation of low levels of carbide-forming elements.[25] There is a possibility of an abundance of ultrahard metallic carbides in the steel matrix precipitating out in bands. Wootz swords, especially Damascus blades, were renowned for their sharpness and toughness.
Steel manufactured in Kutch particularly enjoyed a widespread reputation, similar to those manufactured at Glasgow and Sheffield.[15]
The techniques for its making died out around 1700.[citation needed] According to Sir Richard Burton,[26] the British prohibited the trade in 1866:
Reproduction research[edit]
Russian metallurgist Pavel Petrovich Anosov (see Bulat steel) was able to reproduce ancient Wootz steel with almost all its properties and the steel he created was essentially identical to traditional Wootz. He documented four different methods of producing Wootz steel that exhibited traditional patterns. He died before he could fully document and publish his research. Dr. Oleg Sherby and Dr. Jeff Wadsworth and Lawrence Livermore National Laboratory have all done research, attempting to create steels with similar characteristics to Wootz, but without success. J.D Verhoeven and Al Pendray reconstructed methods of production, proved the role of impurities of ore in the pattern creation, and reproduced Wootz steel with patterns microscopically and visually identical to one of the ancient blade patterns. There are other smiths who are now consistently producing Wootz steel blades identical to the old patterns.[citation needed]
One must remember while looking at reproduction efforts that Wootz was made over nearly a 2000 year period (the oldest sword samples date to around 200 AD) and that the methods of production of ingots, the ingredients, and the methods of forging varied from one area to the next. Some Wootz blades displayed a pattern, some did not. Heat treating was quite different as was forging, and there were many different patterns which were created by the various smiths who spanned from China to Scandinavia. It is easy to say that Wootz/Pulad/Bulat/Hindwani is one pattern and one method with one blade characteristic, but that is not a correct representation of the blades that we have or the accounts of witnessed methods from antiquity. Not all of the secrets of Wootz have been discovered, but it has essentially been recreated by Anosov, Pendray and many smiths in the 20th century. Research still continues however.
There are also experiments documented on YouTube.