抄録
Recently a number of interesting data of the substitutes for Ni-Cr steels have been published, while the chief defect of these substitutes lies in the mass effect in quenching.
The mass effect is concerned mainly with the critical cooling rate, when the thermal conductivity of specimen and the cooling capacity of quenching medium are the same, and the cooling rate in the center of cylindrical specimen is almost inversely proportional to its diameter. Thus, if the critical cooling rate is given, the mass effect may be inferred at once.
The authors determined the critical cooling rate of special steel samples and the relation of the cooling rate to the diameter when quenched in water or mineral oil, and studied the mass effect of C, Ni-Cr and Cr-Mo steels.
