Transactions . and ^were provisionally comprised under the name * Proc. Inst. Mech. Eng., April, 1895, p. Thesis, Gauthier-Villars, Paris, 1895. 892 MICROSTRUCTURE OF STEEL AND THEORIES OF HARDENING. of ? iron. We ought even, at present, to consider it possible,in view of the experiments of Dr. Ball* and M. Curie, that itmay still be necessary to subdivide y iron. A small difficulty now presents itself which had not hithertobeen raised. Mr. Sauveur does not seem to be quite certainthat the points A3 and A., of the iron are included in the doubleor triple points A3,2 or As, 2,1 of the ste
Transactions . and ^were provisionally comprised under the name * Proc. Inst. Mech. Eng., April, 1895, p. Thesis, Gauthier-Villars, Paris, 1895. 892 MICROSTRUCTURE OF STEEL AND THEORIES OF HARDENING. of ? iron. We ought even, at present, to consider it possible,in view of the experiments of Dr. Ball* and M. Curie, that itmay still be necessary to subdivide y iron. A small difficulty now presents itself which had not hithertobeen raised. Mr. Sauveur does not seem to be quite certainthat the points A3 and A., of the iron are included in the doubleor triple points A3,2 or As, 2,1 of the steels. To me, however,the existence of such a doubt seems impossible for the follow-ing reasons: 1. When conducting experiments on the cooling of steelswith an increasing percentage of carbon, it is easy to fol-low the displacement and running together of the critical points. 2. Prof. Arnoldf has calculated the numbers of calories re-leased at the point Arv at the same time deducting the sum of Fig. 5. Pure Iron. 600 500 400 300 200 100 Temperatures (degrees C.) Relative Proportions of Each Variety of Iron Occurring in Pure Iron During Slow Cooling. Ar3 + Ar2 from the supposed triple points, and has found thatthese calories were proportional to the percentage of carbon upto per cent. It is true that the method of calculation wasnot very exact; but the results, though approximate, well justifythe hypothesis. 3. The appearance of magnetism, which is characteristic ofthe point Ar„ occurs in points Ar»,2 or Ars,2,i, which, it is ad-mitted, include 4. The curves of thermo-electric power§ and of electrical re- * Jour. Iron and Steel Inst., 1S90, No. I., p. 85. t Proc. Inst. Civ. Eng., vol. exxiii., p. 152, I Hopkinson, Proc. Roy. Soc., vol. xlviii., 1890, p. 442. \ Osmond, Transformations of Iron and Carbon, pi. vii. and viii. MICROSTRUCTURE OF STEEL AND THEORIES OP HARDENING. 893 sistance,* considered in relation to temperature, reveal the ex-istence at the point A3, wh
Size: 1275px × 1960px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
