Iron in Ancient India c7.s3.2

c7.s3.2

*Iron chisel*: The transverse section shows that the chisel has been carburised, the section showing the carburised areas to be on two sides. The carburisation varies on two faces from saturation point (‘9 per cent) to about ‘2 per cent certain on the outside edge and the depth of carburisation from the edge inwards is also shown to be variable. The presence of matensite and hardenite suggest the important information that the chisel has been quenched. Further micro-sections were prepared from the specimen cut from the nose of the chisel. These photo-micrographs also appear to carry evidence that the chisel has been quenched for the structure is in parts martensitic. Troostite is certainly also present, which is probably the result of tempering by the long lapse of time. Hadfield believes that for the first time there has been put on record evidence of the art of cementation having been known 1500 to 2000 years ago, as shown by these specimens; probably, therefore, such knowledge could be traced back still further.