A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v1.c14.13

v1.c14.13

"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 extact degree by interrupting this de-carbonsing process exactly at the proper time in order to cast steel of a quality exactly suitable for the purpose."