Iron in Ancient India c9.s3.24

c9.s3.24

As regards the proportion of carbon contained in steel, the excess of carbon is burnt away during reheating. In this connection the remarks of Ritter Cecil von Schwarz, who was for some time in charge of the Bengal Iron Works Company, would be interesting. He wrote: "It is well known by every manufacturer of crucible cast-steel how difficult it is sometimes to get the exact degree of hardness to suit certain purposes, especially with reference to steel for cutting the blades, etc. With the ordinary process endeavours are made to reach the required degree of hardness by selecting such raw materials as on an average have the required contents of carbon in order to correspond with the required degree of hardness as far as possible. The natives (of India) reached this degree by introducing into their cast-steel an excess of carbon, by taking this excess gradually away afterwards, by means of the slow tempering process, having it thus completely in their power to attain the exact degree by interrupting this decarbonising process exactly at the proper time in order to cast steel of a quality exactly suitable for the purpose." ²