326.    BRAMLEY, A., AND JINKINGS, A. J.  Gaseous Cementation of Iron and Steel.  I.  Cementation by Carbon Monoxide.  Iron and Steel Inst., Carnegie Schol. Mem., vol. 15, 1926, pp. 17-69; Chem. Abs., vol. 21, 1927, p. 1622. 

                  Carburizing action of CO is studied by placing test bars in a SiO₂ tube, glazed inside and out and heated with Nichrome wire, the gas being generated by the action of concentrated H₂SO₄ on HCOOH.  Preliminary experiments showed that it was necessary periodically to reverse the direction of flow of the gas and support the bars centrally in the furnace tube to obtain uniform carburization.  Thoroughly dry gas was essential.  A detailed study was made of the amount and distribution of C introduced during the process of cementation, as affected by (a) the rate of flow of the gas through the furnace, (b) the period of carburization, (c) the temperature of carburization, (d) the concentration of C in the original steel. Curves and photomicrographs are shown.  No evidence of the liquidation described by Giolitti was found.  In the low-C steels the increases in diameter are in the same order as the weight of C introduced.  In the bars carburized below 900° and those originally containing considerable amounts of C, the changes in dimensions were small.