Ferrous Metallurgy in Ancient India

The discovery of fire and its controlled use in Pyro-technology has been an important landmark in the progress of human civilization and materials technology. The paper discusses the knowledge of the ancient pyrometallurgical
process of iron production, the smelting furnace design, construction and its operation used by Munda and Agaria tribes. It also discusses thermo-chemistry and the physico-chemical processes those go on inside the ancient iron smelting furnace and the principles of its process control. The wrought iron produced by the bloomery furnace contained a maximum of 0.4% C which was carburised to produce case carburised, and laminated steel. Another type of steel produced in the country since 400 BC was known as 'ukku' in the southern language and it became world
famous by the name of Wootz steel. Two distinct processes. viz., (i) carburization of wrought iron and melting carried out inside a closed refractory crucible, and the other (ii) process of manufacture of steel by decarburiz-ation of white cast iron by its reaction with synthetic
slag have been described. Lastly the paper gives a brief description of the ancient smithy craft used for producing some of the heaviest forgings of the world like iron pill-ars at Delhi and Dhar, iron beams of Konark and the iron guns of Bijapur and Tanjore. The forging and heat treat-ment of Wootz steel containing ultra high carbon required
special skill known only to the Indian blacksmiths, and latter learnt by Syrians to produce world famous Damascus sword made of this steel.The surface finish known as Water-ing mark or Damask pattern was the hallmark of original Wootz steel sword.