The Iron Pillar at Delhi

The massive Iron Pillar located in South Delhi has been an object of considerable interest to modern scientists and technologists for two main reasons viz., the amazing technology by which a metallic object weighing nearly seven tons could be fabricated over fifteen centuries ago and the phenomenal corrosion resistance displayed by this ancient monument despite exposure to sun, rain, wind and dust for so long. In this paper all available material on this metallurgical marvel is examined scientifically
and systematically and an attempt made to answer such questions as are likely to arise in the minds of discern-ing visitors to this impressive monument. The following important conclusions are arrived at: (1) Date of Erec-tion : 370-375 A.D., (2) Date of the Inscription : 380-385 A.D., (3) Mode of Fabrication.: Hammer forging and welding ball of hot pasty iron in many steps, and (4) Reasons for Restlessness : Il4any viz., unusual chemical composition, protective oxide film, favourable Delhi climate and slag particles at grain boundaries.