Surya P. Mehrotra

S P MehrotraProf. S.P. Mehrotra, an expert in metallurgy and material science, had a long academic career at IIT Kanpur, eventually heading its Metallurgical Engineering Department and its Advanced Centre for Materials Science. From 2002 to 2009, he was Director of the National Metallurgical Laboratory at Jamshedpur. He has authored numerous research papers and a book on the history of IIT Kanpur. Prof. Mehrotra has been the recipient of many awards, including the Tata Gold Medal of Indian Institute of Metals (2007) and the SAIL Gold Medal of Indian Institute of Metals (2002). Since 2012 he has been Visiting Professor at IIT Gandhinagar, where he was Dean of R&D and continues to look after External Relations; he is also Co-coordinator of IIT Gandhinagar’s Archaeological Sciences Centre.

Abstract of the lecture: Iron and Steelmaking in Ancient India

An archaeological timeline is identified when humans started using different metals / alloys. Copper is considered to be the first metal used by humans, closely followed by gold / gold-silver alloy. The timelines for the onset of the Iron Age in different parts of the world and in the Indian subcontinent are discussed. Based on several recent excavations and evidences now available, it is established that the Iron Age in the Indian subcontinent began several centuries before the timeline hitherto accepted by the global archaeological community. Iron production in India probably began as early as the Vedic era, as there is unambiguous mention of this metal in the Vedic literature. Interestingly, production of iron by pyrometallurgical extraction process was not confined to just a few locations but was well spread over different regions of southern, eastern, central and northern India. The technology used was essentially based on reduction of oxide iron ore (primarily, Haematite — Fe2O3) with wood charcoal.

In India steelmaking based on the ‘crucible’ technology was also well developed around the 1st millennium BCE. The world famous ‘Wootz’ steel, used for producing Damascus swords, was regularly exported to Syria and other Middle-Eastern countries. The commercial impact of these technologies is discussed. The unique microstructure of this steel resulted in extraordinary mechanical properties in terms of strength and ductility. Also discussed is the difficulty in reproducing the steel with a similar microstructure and mechanical properties in spite of the advanced technologies of steelmaking available today.