Ancient Indian wisdom-IRON & STEEL MAKING PROCESS

Ancient Indian wisdom-IRON & STEEL MAKING PROCESS

IRON & STEEL MAKING PROCESS

Experts at the Indian Institute of Technology have resolved the mystery behind the 1600-year-old iron pillar in Delhi which has not corroded despite the capital's harsh weather. Metallurgists at Kanpur IIT have discovered that a thin layer of 'misawite', a compound of iron, oxygen and hydrogen, has protected the cast-iron pillar from rust. The protective film took form within three years of the erection of the pillar and has been growing ever so slowly since then. After 1600 years, the film has grown just one-twentieth of a millimetre thick. The protective film is formed catalytically by the presence of high amounts of phosphorous in the iron - as much as one percent against less than 0.05 per cent in today's iron.

The high phosphorous content is a result of the unique iron-making process practised by ancient Indians who reduced iron ore into steel in one step by mixing it with charcoal. Modern blast furnaces, on the other hand, use limestone in place of charcoal, yielding molten slag and pig iron that is later converted into steel.

In the ancient times Indian iron enjoyed good reputation internationally. Arabs and Persians yearned for swords made of Indian iron. The renowned metallurgist Prof. Anantraman has explained the iron-making process. Iron ore, wood and carbon powder were mixed and heated in earthen barrels up to a temperature of 1535 degrees centigrade and then gradually cooled for 24 hours to achieve iron with high carbon content. The British called it Butz. In the 18th century European metallurgists tried to manufacture iron like the Indians but they failed.

In his book "Indian science and technology in the eighteenth century" Shri Dharmpalji has mentioned the evidence given by the Europeans of the advanced method of manufacturing iron in India. In a report sent to East India Company in 1795 Dr. Benjamin Hayan describes that Ramnath Peth is a beautiful village around which there are mines and 40 iron making furnaces. The cost of iron manufactured in these furnaces is only Rs. 2 per mann, hence the company should think in this direction.

In another report James Franklin writes about steel manufacturing in Central India. He mentions iron mines in Jabalpur, Panna, Sagar, etc. and that charcoal was used in making iron all over India. A report by Captain J. Campbell in 1842 describes iron manufacturing in South India.

All these reports show that there were small furnaces all over India. Each furnace used to provide employment to nine persons and generated iron which was high in quality but cheap in price. While obtaining bar iron for railways, Campbell has emphasized that the bar iron of India is high in quality but low in cost. The best quality iron from England could not cope with the worst quality Indian iron.

90000 people worked in small iron furnaces in those days. The British established Bengal Iron Company in 1874 and started iron manufacturing on a large scale. Also more expensive iron was imported from abroad. As a result, the sale of the small furnaces went down and by the end of the 19th century the swadeshi iron industry was almost dead. The knowledge of this ancient technique is still possessed in few vanvasi families in Jharkhand.