The Iron and steel magazine . in the slowly cooled steelsa carbide of the composition Fe3C is contained, which in dissolvingthe steel in dilute acids remains behind as a heavy powder and,as we have seen above, furnishes as cement ite a constituent ofthe structure. It is striking that the quantitative determina-tion of this carbide cannot be performed by dissolving the mate- 210 The Iron and Steel Magazine rial carefully in dilute acids. Photograph 26 shows us thestructure of a white iron which was slowly cooled, hence consistsonly of free cementite and pearlite. The total carbon is cen
The Iron and steel magazine . in the slowly cooled steelsa carbide of the composition Fe3C is contained, which in dissolvingthe steel in dilute acids remains behind as a heavy powder and,as we have seen above, furnishes as cement ite a constituent ofthe structure. It is striking that the quantitative determina-tion of this carbide cannot be performed by dissolving the mate- 210 The Iron and Steel Magazine rial carefully in dilute acids. Photograph 26 shows us thestructure of a white iron which was slowly cooled, hence consistsonly of free cementite and pearlite. The total carbon is cent, and ought, according to the customary method of deter-mining carbide, remain completely in the carbide residue. Yetthe calculation of the carbon contained in this residuum gaveonly per cent, that is, a loss of — = per centcarbon, about 41 per cent of the total carbon. Photograph 27shows the structure of a slowly cooled gray iron with a totalcarbon content of per cent. If we subtract from this the. Fig. 27. Magnified 500 diameters graphite, , there remains — = per cent, com-bined carbon. The direct determination gave per cent car-bon in the carbide, wThich again corresponds to a loss of — = per cent of total combined carbon. In what waythis loss, which is also to be noted in all the other tests, can beexplained, could not be determined. Of course its regularappearance shows that the views concerning the composition ofthe different components of iron are not to be brought into agree-ment with the results of chemical analysis. The view of Benedick * that the ferrite of the different * Reeherches physiques et physico-chimiques sur lacier au car-bone, A. Felix, Leipzig. 1 />/>// Blai t 2 I I varieties of iron with more than per cent whole carbon couldhold some carbon in solution, mighl perhaps pass as a sufficienl explanation of the phenomenon for the kinds of steel which heexamined, but is not satisfac
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Keywords: ., bookcentury1800, bookdecade1890, bookidironsteel, booksubjectiron
