3516. UMINO, S. Specific Heat of Iron-Carbon System at High Temperatures, and the Heat Changes Accompanying Those in Phase. Sci. Repts. T˘hoku Imp. Univ., 1st ser., vol. 23, 1935, pp. 665-793; Chem. Abs., vol. 29, 1935, p. 4253.
Heat content of 19 Fe-C alloys containing 0.07-5.07% C was measured at numerous high temperature sup to and beyond the melting point. Electrolytic Fe and sugar were used in preparing the melts. The heat of fusion of the δ-alloy containing 0.03% C is 65.31 cal.; 0.07% C, 64.90 cal.; of the γ-alloy containing 0.13% C, 67.19 cal.; 1.70% C, 57.8 cal. the heat of fusion of the eutectic is 60.91 cal. That of cementite, by extrapolation, is 65.0 cal., its melting point being estimated to be 1,600░. The heats of transformation of the a- into the γ-Fe at the A3 point are calculated to be 5.59 cal. for pure Fe and 16.60 cal. for the eutectoid at 720░. The heat of solution of Fe3C in γ-Fe of 0.90% C is 11.15 cal. at 720░; it decreases with rise in temperature and C concentration. The heat of the A0 transformation of Fe3C is estimated to be 9.35 cal.