How it began
Wootz steel was developed in southern India. Wikipedia dates it to the mid-1st millennium BCE, and metallurgists S. Srinivasan and S. Ranganathan of the Indian Institute of Science write that archaeological evidence from Tamil Nadu suggests the Indian crucible steel process is likely to have started before the Christian era in that region. Production sites have been identified in Tamil Nadu, Karnataka and the Hyderabad region, and related sites are known in Sri Lanka. The word wootz is an anglicized form of ukku, the word for steel in the languages of Karnataka and Andhra Pradesh.
How it works
Wootz was made by a closed crucible process. In sites studied in Tamil Nadu and Karnataka, wrought iron was packed with carbonaceous material such as stems and leaves in a small clay crucible and heated until it absorbed carbon and melted. In the Deccan a variant melted cast iron together with wrought iron. A furnace sketched by Francis Buchanan in 1807 held about fifteen conical crucibles in an ash-filled pit blown by buffalo-hide bellows. Temperatures above 1,400 degrees Celsius were reached, and firing could last up to 24 hours. The product was an ultra-high carbon steel with 1 to 2 percent carbon.
How it spread
Literary accounts indicate that steel from southern India was traded to Europe, China, the Arab world and the Middle East. Arabs took ingots of wootz to Damascus, where an industry grew up making weapons and armor from it, and the renown of that industry gave Damascus steel its name. In the 12th century the Arab writer Edrisi wrote that nothing surpassed the edge of Indian steel. By the late 1600s shipments running into tens of thousands of wootz ingots were traded from the Coromandel coast to Persia.
Who pushed back
European smiths long failed to reproduce the material. They were used to forging low-carbon steels at white heat, and wootz forged at that heat crumbled under the hammer. In 1820 Michael Faraday and the cutler Stodart wrongly concluded that additions of aluminum oxide and silica explained its properties. In the 1820s Breant of the Paris mint ran about 300 experiments before concluding that the properties came from carbon. True Damascus steels were not replicated in Europe until 1821.
What lasted
The effort to understand wootz stimulated European metallurgy. The role of carbon as the dominant element in steel was found in 1774 by the Swedish chemist Tobern Bergman, in work prompted by attempts to unravel wootz, and British, French and Russian metallography developed largely from the quest to document its structure. In 1912 Robert Hadfield recorded that Indian wootz was far superior to steel previously produced in Europe.
Where it stands today
The traditional centers that made wootz blades in India until the 19th century, among them Jaipur, Gwalior, Tanjore, Mysore and Golconda, no longer survive. Research continues: Stanford University found by 1975 that steels with 1 to 2.1 percent carbon can be superplastic, and J. D. Verhoeven and Alfred Pendray reproduced blades with the banded pattern, showing the role of trace elements such as vanadium.
