The specific heat of the 10 alloys consisting of iron and chromium less than 55.57 percent was measured at high temperatures in annealed, quenched and baked states by an inverse rate curve method. In the case of the alloys containing less than 24.31 percent of chromium, the specific heat-temperature curves in the annealed state showed a maximum due to the magnetic transformation and an anomalous maximum at about 520° to 560°; the temperatures of the former became lower and of the latter higher with the increase in chromium content. In the alloys containing more than 28.58 percent of chromium, the both maxima combined in a new maximum. The combined maximum was most conspicuous in the alloys containing 28.58 to 36.45 percent of chromium, existing at about 570°, and when the chromium content was further increased it became smaller and its temperature lower; especially, the σ phase alloy containing 43.16 percent of chromium showed a very small maximum. However, when the alloys were baked at 475° for 200 hours, these maxima became very much larger and especially so in the σ phase alloy. When the alloys were quenched from 850°, the specific heat curves showed a minimum (heat evolution) at about 400° to 500° and a small maximum at a higher temperature. Thus, it has been concluded that the anomaly may be caused by the existence of a superstructure Fe3Cr, which is the cause of the high temperature brittleness of the alloys.
According to the rule on the small expansibility of invar, previously proposed by one of the present investigators, they expected that there would be invar and elinvar-type alloys in the system of cobalt, iron and vanadium. So, they measured the thermal expansion of the alloys containing 50 to 80 percent of cobalt and less than 13 percent of vanadium and found that an addition of vanadium to cobalt-iron alloys considerably reduced their expansibility. The smallest coefficient of linear expansion in the temperature range of 10° to 50° was 3.94×10−6 in the alloy containing 56 percent of cobalt and 9 percent of vanadium. They also measured the mean temperature coefficient of rigidity modulus of the alloys in the temperature range of 20° to 50° by a torsion pendulum method and found that the coefficients of most alloys were negative, while as the concentration approached the composition, at which the thermal expansion coefficient was minimum, the coefficient diminished, first gradually and then rapidly, became zero at a certain composition and afterwards changed its sign. Then the coefficient reached a positive maximum (+31.5×10−5) in the alloy showing a smallest expansion coefficient. Thus, it will be seen that there are many elinvar type alloys in this ternary system. Further, the rigidity modulus at 20° of the alloys was also determined with the result that the modulus showed a maximum value (8.46×105 kg/cm2) at the composition containing 55 percent of cobalt and 13 percent of vanadium and a minium (5.40×105 kg/cm2) at that containing 63 percent of cobalt and 7 percent of vanadium.
The magnetic properties of iron-silicon-aluminium alloys in weak field were measured at various temperatures. An alloy containing about 9% Si, about 5% Al and the rest iron, namely, Sendust, showed an abnormal change of magnetic properties almost at 450°. It is assumed that this abnormality is intimately connected with the formation of superlattice. Then, the statistical and dynamical magnetic properties of the specimens were measured, the compositions of which were on the line connected with Fe3Si and Fe3Al in the triangular diagram of Fe-Si-Al system. All specimens measured had an abnormal change of magnetic properties at the order-disorder transformation point.
Single crystals of Al with various orientations were lightly extended. The appearances of cluster slips and the banding behavior were checked by the orientations all over the standard stereographic projection. Cluster slips and deformation bands were found to be related to the angle of θ, (the angle between stress axis and the normal to the slip plane) and to \varphi, (the angle between slip direction and the projection of the stress axis to the slip plane). As the results, cluster slips were found to be formed in the specimen having the orientation of large angle of θ, and \varphi. Therefore, these specimen axes are oriented not only to  but also to  in the standard projection. The specimens whose axes oriented near to  have extremely cross slips. Furthermore, interesting appearances of slips which were observed are discussed.
In the first stage of polishing, it was observed that comparatively sharp reflections of Fe were overlapped with several reflections of oxides a little diffused. In the 2nd stage the diffusion of diffraction rings advanced and the discrimination of individual lines became difficult except the (111) of Fe3O4. But the position of general maximum of the intensity suggested further formation of oxides. This inclination proceded for some time. In the final stage of polishing the diffraction patterns became very akind to those so-called the general halo-patterns of polish, although the diffused (111) line of Fe3O4 never distinguished. According to the results of the experiments it was interpreted that the progression of oxidation was great in the beginning stage of polishing, while in the final stage the oxidation became weak or stopped. The displacement of the general maximum of halo-rings in the final stage might even be thought to suggest the reformation of Fe or the reduction. The resulted halo-patterns of polished Fe were interpreted to be the complicated duplication of diffused lines of Fe and Fe3O4 and the essential halo-rings by the polished structure of Fe. The surface structure of polished Fe was such that the Fe matrix was finely inlayed and all over by strongly deformed fine particles of oxides, as verified by the persistent survival of (111) line of Fe3O4.
In this report, the experiments were carried on Fe-W, Fe-C-W, Fe-C-Cr-W, Fe-C-Cr-Ni-W and Fe-C-Si-Ni-Cr-W alloys for the following items: (1) the change of HCl (37%) quantity in the 3% Cu(NH4)2Cl4·2H2O solution, (2) the relation between optimum replica solutions and corrosive reduction by HCl, (3) the concentration of Cu••, H• and Cl′, (4) the relation between optimum replica solution and structure of alloys and (5) the compositions of replica solution in Fe-C-W, Fe-C-Cr-W, Fe-C-Cr-Ni-W and Fe-C-Si-Cr-Ni-W alloys. The used samples are shown in the Tables 1 and 2. The results of experiments are shown in the Tables 3 and 4. In the chemical plating, some relations are found between the ions of Cu••, H• and Cl′ in the replica solution which varied according to the concentrations of W in the iron. Substituting the concentration of H• and Cl′ by HCl quantity, these relations are shown in the Fig. 1. In this figure, the newly gained HCl curve is symmetrical to the corrosive reduction curve against the streight line which is kept at 2/5. The replica solutions which contain HCl quantity in the range of 1.72 to 2.95 cc can be replaced in the structure of meny Fe-W alloys which are expected to be ε and δ. Next, HCl quantities in the replica solution for Fe-C-W, Fe-C-Cr-W, Fe-C-Cr-Ni-W and Fe-C-Si-Cr-Ni-W alloys are shown by the mean value of HCl quantities which were used in the case of replica of every Fe-C, Fe-Ni, Fe-Cr, Fe-Si and Fe-W alloys.
In this report, the experiments were carried on Fe-Mo, Fe-C-Cr-Mo, Fe-C-Cr-W-Mo and Fe-C-Ni-Cr-Mo alloys on following items: (1) the change of HCl (37%) quantity on the 3% Cu(NH4)2Cl4·2H2O solution, (2) the relation between optimum replica solutions and corrosive reductions by HCl, (3) the concentration of Cu••, H• and Cl′, (4) the relation between optimum replica solution and structure of alloys and (5) the compositions of replica solution on the Fe-C-Cr-Mo, Fe-C-Cr-W-Mo and Fe-C-Ni-Cr-Mo alloys. The used samples are shown in the Tables 1 and 2. The results of expeliments are shown in the Tables 3 and 4. On the chemical plating, some relations were found between the ions of Cu••, H• and Cl′ in the replica solution which varied according to the concentrations of Mo in the iron. Substituting the concentration of H• and Cl′ by HCl quantity, these relations are shown in the Fig. 1. In the figure, the newly gained HCl curve is symmetrical to the corrosive reduction curve against the streight line which is kept at 1/3. The replica solutions which contain HCl quantity in the range of 1.32 to 1.67 cc can be replaced in the structure of many Fe-Mo alloys which are expected to be δ. Next, HCl quantities in the replica solution for Fe-C-Cr-Mo, Fe-C-Cr-W-Mo and Fe-C-Cr-Ni-Mo alloys are shown by the mean value of HCl quantities which were used in the case of replica of every Fe-C, Fe-Cr, Fe-W, Fe-Ni and Fe-Mo alloys.
The effect of the reaction on steel in carburizing atmospheres mingled with ammonia, the atmosphere being produced by the combustion with dry air, was studied under various conditions and the following results were obtained. (1) Steel can absorb simultaneously carbon and nitrogen from such atmospheres. (2) The amounts of carbon and nitrogen in the case of steel increase in accordance with ammonia content at low temperature. (3) Nitrogen concentration in the case decreases with the rise of operating temperature and carbon concentration readily surpasses 2% between 700° to 800°, even in such a weak carponizing atmosphere. (4) The amount of carbonitriding is not effected by the carbon content of steel at high ammonia concentration and low temperatures.
If the specimen of mild steel of which surface is polished as flatly as a mirror, is carburized with weak carburizer, the graphite is deposited along the grain boundary of austenite. Applying this phenomena, we found a new method of determining austenite grain size, called “graphite method”, which was simpler and speedier than other methods. And the transition of austenite grain boundary by heating and cooling through A1 point was also observed.
Many studies have been attempted for years on the annealing of quenched carbon steels. In this paper, the effect of heating velocity in tempering was investigated. For this purpose, a special designed furnace was addopted for rapid heating, by which the heating rate of about 300°C/min was obtained. Using this furnace the changes of electric resistance and thermo-electro motive force in rapid tempering were measured done. The electric resistance values changed at two steps: the first steps which was seen at a low temperature, was not affected by the heating rate; but the second step which was seen at a higher temperature was affected by heating rate; in rapid heating the step shifted to the higher temperature side. The thermo-electro motive force seems to be showed only one change which was analogous to the first-step of resistance curve in temering. And the change was little affected by heating velocity, but the occuring temperature differed with carbon content of sample: the higher the carbon contents the lower the changing points of thermo-electromotive force was, and in low carbon steels the main change occured at a comparatively high temperature. This result is analogous to the relation between the Ar″ point and carbon content in quenching.
Using high chromium steels containing about 25%Cr and different carbon and titanium contents, the change of hardness and toughness due to various heat treatments, and resistivity for corrosion by HNO3 and NaCl solutions were studied. From the results obtained it is concluded that the quality of high chromium steels containing about 25% Cr is markedly refined on addition of 0.1∼0.3% of Ti and that, by rapid cooling from 800∼900°, the hardness decreased most, while the toughness increased; the less carbon content of steels shows better properties.
The steel scrap was carburized by electrode-carbon, charcoal, coke or charcoal plus CaC2, and the irons containing 3.10∼3.39% C were made. Using specimens cast in dry sand mould 14 mm in diameter, the effect was investigated of the carburizing method on the spheroidization of graphite in these irons by the addition of 0.1∼0.5% Mg in the form of Mg-Ni-Si-Fe-Cu-Al alloy containing 10% Mg, and the following results were obtained: (1) The sulphur-content in electrode-carbon-, charcoal- or coke-treated irons was higher than that in the original steel scrap, while the sulphur-content in charcoal plus CaC2-treated iron was remarkably lower than that in the original steel scrap. (2) Charcoal plus CaC2-treated iron was most suitable for the spheroidization of graphite by the magnesium-addition on account of the pig-making with the basic and reducing atmosphere accompanying the strong desulphurization. (3) In the case of charcoal plus CaC2-treated iron, the spheroidizing effect of magnesium appeared with but few addition of 0.1% Mg. While, in iron treated with charcoal, the spheroidizing effect was seen at 0.15% Mg-addition, and in irons treated with electrode-carbon or coke, it was seen at 0.2% Mg. (4) Though in iron treated with charcoal plus CaC2 the spheroidization of graphite can be completed by the magnesium-addition, the spheroidal form is gradually disintegrated in irons of the other carburizing method even by abundant addition of magnesium in the following order: charcoal, electrode-carbon, coke. This fact signifies that some elements except common ones in irons have fatal effect on the spheroidization of graphite and the so-called inherrent properties of irons caused by the pig-making method have the intimate relation with the spheroidizing of graphite.
When the solidmetal electrode was used for the quantitative pectral analysis of Al-base alloy, we recognized that extraneous elements gave some influence to the quantity of the subjected elements. For the study of this phenomenon, the author made the solution whose compositions are almost the same as the solid metal electrodes, and compared the results by the special emission method of the solutions which the results by ordinary solid metal electrode method. By the solid metal electrode method, some influence of Zn on fixing Mg quantity in Al, and of Mn on Cu quantity were recognized, but there were no influence of extraneous elements by the solution method.
Contact resistance, transference magnitude and direction, and contact plane, of some metals Ag, Cu, Cd, Zn, Sn, Pb, Bi, Sb, Fe, Ni, W, Al, Mg, Ca, Sb, in the circuit of 6 V 1 A, 6 V 10 A and, 24 V 1 A and 6 V 1 A with small inductance were observed with the following results: (1) Efficiency of the contact was affected by the increase in voltage were than that in amper in the circuit. (2) Contact property of Cd is less inferior to that of Ag. (3) Transference direction is inverted in a cirtain voltage, which is likely to be related with ionization of the contact material or the atmosphere.
Raw city gas as such can not be utilized as atmosphere for bright heating or carburizing of steels. The objects of this research was to convert raw city gas into the atmospheres for bright heating or carburizing of steels. The author devised a conversion furnace for city gas and studied its ability under various conditions. As the results, it was confirmed that the converted atomospheres can be utililized for the above purposes.