. Transactions. and reduction of areaare about 100 per cent. The forgeabihty should, therefore, increasewith the temperature, which was found to be the case, although the alloyforged very well at all temperatures. The per cent, titanium has,therefore, entirely changed the characteristics of the 20-per cent, alloy,probably by strengthening the intercrystalhne material relatively tothat of the crystals. The structures of these alloys were examined byMr. Pilling and are shown in Figs. 11, 12 and 13. Fig. 11 (1870-1) and Fig. 12 (1871-1) show the difference in thestructure of the non-forgeable
. Transactions. and reduction of areaare about 100 per cent. The forgeabihty should, therefore, increasewith the temperature, which was found to be the case, although the alloyforged very well at all temperatures. The per cent, titanium has,therefore, entirely changed the characteristics of the 20-per cent, alloy,probably by strengthening the intercrystalhne material relatively tothat of the crystals. The structures of these alloys were examined byMr. Pilling and are shown in Figs. 11, 12 and 13. Fig. 11 (1870-1) and Fig. 12 (1871-1) show the difference in thestructure of the non-forgeable 20-per cent, alloy 2Ni274 and theforgeable 20-per cent, alloy, 2Ni275, the only difference ,in the com-position of the two being that the latter contains per cent, titanium. 504 FORGEABILITY OF IRON-NICKEL ALLOYS The photomicrographs were obtained from the heads of the tensile testpieces, after the tensile test. Fig. 13 (1872-1) shows, similarly, thestructure of the non-forgeable 30-per cent, alloy^ 400 500 600 700Temperature, Degrees C Fig. 2. ^ Attention is called to the fact that this alloy has not passed the irreversibletransformation point, which is below room temperature, and is, therefore, largely inthe austenitic, non-magnetic state. However, examination of this alloy after beingcooled to —180° C. shows that there is no visible change in the microstructure dueto the transformation from the austenitic to the a state. (Magnetic and ElectricalProperties of Iron-nickel Alloys, Part II, Trans. Amer. Inst. Elec. Engrs., Oct., 1919.) T. D. YEXSEX 505
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
