特殊鑄鋼の研究 (VII) : 特殊鑄鋼の結晶粒度に就て

概要

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By addition of Si, Mn Ni etc. to Cr-Mo cast steels and W, V, Ti, Al etc. to Cr-Mn-Si cast steels, their effect on the grain size was investigated by means of carburization test at 925℃ for 6 honrs. Further the same examination was carried out on the effect of grain growth on the austenitic or martensitic structure by a superheated carburizing method at 900゜∿1150℃ for 6 hours and by oil quenching at the same temperature (held for 20 minutes.) As result of study on the grain growth of these steels, it was found that Cr-Mo cast steel added with Mn started to coarsen at 950℃∿1000℃, while Mn-Si cast steel added with Cr did at 1000℃. In Si, Ti, Al added cast steels, however, coarsening was not recognized at temperatures below 1100℃ Tests on these cast steels indicate that the addition of Si, W, V, Ti or Al has a marked effect on grain refining and inhibition of grain growth, but the addition of Ni or Mn has no such essential effect. Examination of many special cast steels shows that the coarsening temperature for low or medium carbon steels varies between Ac_3 points and 1100℃, but the growth of grains is especially remarkable at temperature between 950°∿1100℃., and the steels that begin to coarsen at temperatures above 1000℃ are rare. Mechanism of inhibition for austenitic grain growth was also inquired.
社団法人日本鉄鋼協会の論文
1951-12-25