History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s4.28

v1.c13.s4.28

The world famous ‘Wootz’ steel swords were made by forge welding small rods of wrought iron and steel cakes in a very narrow range of temperature and then giving it the traditional ‘watering’ treatment. This must have been possible only by the extensive knowledge about the hot workability of various iron carbon alloys. The cast structure of high carbon hyper eutectoid steel consists of massive platelets of Cementite separating out on Widmanstatten planes and Ledeburite and it is extremely difficult to hot forge it without cracking. Yater (1983,1983-84) and Verhoevens (1987) have discussed the technicalities of forging such steels to produce Damascus swords. The process generally consisted of careful forging of the ingot in cherry red hot (~750°C) condition followed by spherodizing treatment to convert the Cementite plates into spherical massive Cementite. This treatment was followed by cold forging of the sharp edge and low temperature annealing (~800°C). The forged sword blade was cleaned and given proper surface finish before it was hardened.