Ultrahigh-carbon “wootz” from crucible carburization of molten iron: Hypereutectoid steel from “Tamil Nadu Process” at Mel-siruvalur

Abstract

ABSTRACTAs European and Mediterranean accounts indicate, India has been famed for the production of steel, apparently made by crucible processes. Late medieval traveler’s accounts record the making of “wootz” steel in several places in southern India. This material was used for the fabled Damascus swords, which were later found to be of ultrahigh-carbon steel. Whereas studies on Asian crucible steel making from India, Central Asia and Sri Lanka have discussed various processes ranging from co-fusion of cast iron and wrought iron to solid-state carburization of wrought iron, it has been difficult to find clear evidence relating to an end product of ultrahigh-carbon steel. In this light, the archeometallurgical evidence from Mel-siruvalur in Tamil Nadu, presented in this paper, is significant in that it shows unmistakable remnants in crucibles of ultrahigh-carbon, hyper-eutectoid steel, with a likely production mechanism of molten carburization of wrought iron to steel. The favorable comparison with ultrahigh-carbon steel finds dated to early historic or megalithic times in Tamil Nadu and southern India also suggest that this method of crucible steel manufacture, which may be described as the “Tamil Nadu process”, might have been earlier or more archaic than the co-fusion process.