. Railway mechanical engineer . 14, which were in an entirelydifferent zone, as shown by the etching. The numbers in Fig. 2 were the ones for the original testpieces, and may be partly seen in Fig. 3, stamped into thesections. The white numbers in Fig. 4 are the ones later de-cided on, and which are used throughout this article. It appears from Fig. 5 that the changes o* =t-*-e indi- 104 February, 1918 RAILWAY MECHANICAL ENGINEER 105 cated may be divided into four principal zones. These arezone .1, the added material; zone B, the darkest one whichhas the tinest grain, having been heated above
. Railway mechanical engineer . 14, which were in an entirelydifferent zone, as shown by the etching. The numbers in Fig. 2 were the ones for the original testpieces, and may be partly seen in Fig. 3, stamped into thesections. The white numbers in Fig. 4 are the ones later de-cided on, and which are used throughout this article. It appears from Fig. 5 that the changes o* =t-*-e indi- 104 February, 1918 RAILWAY MECHANICAL ENGINEER 105 cated may be divided into four principal zones. These arezone .1, the added material; zone B, the darkest one whichhas the tinest grain, having been heated above the criticalrange and rapidly cooled by conduction of the heat to therest of the tire; zone C, the lightest one which has been heated It is important to remember that, while the zones appear tobe rather sharply defined, the temperature was not uniform inany one zone and gradations within each zone may be ob-served, except in zone D, which has been subjected only to astrong drawing heat, such as occurs some distance back of the. Fig. 3.—Sections Cut Fr the Tire for Test. within the critical range, and, therefore, softened, and zoneD, intermediate in color, which has been heated below thecritical range and, therefore, is not changed from the originalwith regard to grain size. This last represents, as nearly as
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
