The equilibrium relation among SO2 gas and oxygen and sulphur in molten copper, calculated from the theoretical equation obtained in the previous report, was numerically compared with the observed data in a reverberatory furnace and a copper alloying furnace. The results obtained may be summarized as follows: The effect of sulphur content in heavy oil is small in anode copper refining and on the other hand, is great in wire bar refining in a reverberatory furnace. If sulphur content in heavy oil is >0.3%, it is obtained numerically that the sulphur content of copper increases rapidly from 0.005% to 0.007% when the oxygen content is <0.045∼0.05%, and the partial pressure of SO2 is 1×10−3∼5×10−4 atmosphere at 1200°. In these cases, many large blowholes appear in the cast copper. This phenomenon is so called overpoling due to SO2 gas evolution. Next it is shown that in a copper alloying furnace, the observed data are approximately distributed on the equilibrium curves.
Experiments were carried out on the immersion method of electrolytic hardening of steel. The results revealed the following points: (1) The characteristics of electrolytic hardening by various electrolytes were determined. Such metallic salts as K2CO3 or Na2CO3, showed good results. (2) Experiments were made on electrolytes, HCl and Na2CO3, having various concentrations, and 2% HCl and 10% Na2CO3 salutions gave good results. (3) Under equal voltage, the higher the temperature of the electrolyte, the lower the voltage that may be used to heat the specimens. But the optimum temperature is below 40°. (4) Heating can be made effectively when the surface area of the anode is more than 1.14 times that of the cathode (specimen). (5) The distance between the specimen and the anode was varied between 10∼100 mm, but under 210 V, the difference of this distance shows no effect on the current density.
As it has been known that working not only at room temperature but also at high temperature has effects (mainly acceleration) on phase change such as Ar″ and isothermal transformation, it is considered some effects on phase change may be occasioned by KRK treatment. In this paper, the effects of KRK treatment on the precipitation of variously cold-worked corson alloy was examined. As the degree of precipitation is determined by the increase of strength, the tensile strength was measured and the following results were obtained: For quenching specimens, difference in tensile strength by ordinary tempering and by KRK is so small that no acceleration of precipitation is recognised, except in severely cold-worked specimens because the strength becomes larger by KRK than by ordinary tempering regularly in accordance with conditions of KRK. For 20∼60% cold-worked specimens, an acceleration of precipitation is recognised from the hardness and the electrical conductivity but KRK appears to retard precipitation from the fact that the tensile strength by KRK is lower than that by ordinary tempering. This lowering of strength is due to fractures by accelerated precipitation at grain boundaries with lower tensile stress than the true one.
The slide-wear of austenite steel was studied. According to the study much difference was recognized on the wearing phenomena and the factors concerning wear from ordinary steel, as follows. (1) Austenite steel has superiority in the property of thermal and corrosive resistances. Against dry wear, it is more resisting, while against lubricant wear, it is inferior to other steels of which the hardness is higher at room temperature. (2) High manganess steel has high toughness and when deformed at the worn surface, γ phase and also ε phase transform into martensite, and the resistance to wear increases. (3) The worn amount decreases with the increase of the hardness, even if the hardness increases by influence of the working stress. Such an increase of hardness is comparatively stable even under frictional heat, and serves to heighten the wear resistance. Such results may be considered to be opposite to the wearing properties of ordinary steels.
In production of spheroidal graphite cast iron, the production condition varies the size of spheroidal graphite. It has been already confirmed that spheroidal graphite cast-iron is highly superior in wear resisting property than the ordinary flaky graphite cast-iron. In this experiment, the effects of graphite nodule size and the distribution figure among the pearlite matrix on the wear resistivity of spheroidal graphite cast-iron were studied from the view point of establishing a rational estimation for the application of such cast-iron to the brake shoe of cars. The conclusion may be summarized as follows: The spheroidal graphite cast-iron which has rather large graphite nodules is superior to that of small graphite nodules in wear resistivity in spite of the fact the former is appreciably lower in hardness.
The determination of several elements in ferrosilicon is increasing in importance with the newer developments in metallurgy. But often, there is a difference between the actual contents and its analytical values, caused by segregation or errors in the analytical procedure. This paper reports on the standard deviation (σ) for each method, and studies the results with reference to the allowance that is tolerated in practice.
The Wiedemann effect, namely the torsion caused by a circular magnetic field due to an electric current passed through the specimen and a longitudinal field, has been measured at high temperatures with annealed specimens of 13 Fe-Al alloys. With the addition of Al to Fe, the torsion increases at first gradually, but after reaching a maximum at the concentration of about 13% Al, it decreases rapidly. The Wiedemann effects of Fe-Al alloys containing less than about 6% Al at elevated temperatures are similar to that of iron, while the effect of alloys containing more than about 6% Al are similar to that of “Alfer”.
A novel technique using single light figure has been devised for the determination of orientation of small crystal grains, to which the orthodox light-figure method using two light figures cannot be applied. This simple technique, of which the accuracy is at least 1°, can readily be applied to crystal grains with the smallest area of about 1 mm2. It also serves as a simple method of determining the orientation of single crystal rods of arbitrary shapes. Various examples of its application are shown.
To examine the mechanism of solid phase welding, a pair of polished surfaces of the same or different metals were contacted, and then heated and/or compressed together. In these experiments the following results were obtained. It is necessary for a successful solid phase bonding that interface should be heated above the recrystallization temperature at least of one of the metals by means of heating from surroundings, plastic deformation or friction. Only at higher temperatures than the recrystallization temperature of one of the pair, an exerted pressure can reduce the time required to finish bonding. The friction between the contact surfaces can generate a heat at the interface, and the heat can cause bonding only when the temperature of the heated interface has exceeded the recrystallization temperature or melting point of one of the pair. Crystallographically, the solid phase bonding is affected by the relative magnitude of interface and free surface energies. Namely, the bonding is finished the faster the smaller is the interface energy than the free surface energies of the metals. The strength is affected by the ability of grain growth across the interface. Exerting a pressure can accelerate the diffusion and grain growth across the interface. In metals undergoing solid phase transformation, the boundary at the interface disappears when the bonding temperature has exceeded the critical temperature. That is, in solid phase bonding, the solid phase transformation has the same effects as melting.
The corrosion reaction of iron in acid solutions have been studied by means of chemical kinetics. The cathodes of local cells in iron are oxygen electrodes at higher pH than 4 and hydrogen electrodes at lower pH than 4. The corrosion ersistivity of metals K is related to the standard electrode potential EM0 and the specific reaction rate constant of hydrogen electrode K1 by the expression (This article is not displayable. Please see full text pdf.) \
oindentwhere n is the valency of metal ions. 1>α>0, T the absolute temperature and R and F are universal constants. There seems to be some relation between K and the work function of metals. The general Eq. of corrosion rate are as follows: (This article is not displayable. Please see full text pdf.) \
oindentwhere β is a constant of the anode film, β≥1, C is the concentration of adsorbed water molecule on metals, DM is the diffusion constant of metal ions and δm the thickness of diffusion layer.
By constructing the following electrode concentration cell, the author measured the electromotive force corresponding to the change in Si and C in molten Fe-Si-C alloys: ⊕ Fe, Si, C|silicate slag|Si \ominusThe following equations were derived from this experiment in the range up to NSi=0.25 at 1,540°: & logγ_Si’=-2.5(1-N_Si)^2+0.13(1-N_Si)^-3 & logγ_Si=-2.5(1-N_Si-N_C)^2+0.13(1-N_Si-N_C)^-3where γSi′ and γSi are the activity coefficients in Fe-Si and Fe-Si-C alloys respectively. Then the interaction coefficients, γSiC, and γCSi are discussed from the experimental results and theoretical calculations. Furthermore, the iso-activity lines of Si and C have been established in such alloys.
In this report the author made clear the influence of the banded structure of carbon steel bars on their dimensional changes due to heating and cooling and investigated its mechanism. When low carbon steel bars are heated and cooled, the transformations don’t proceed uniformly over the whole of a specimen, the α-phase and γ-phase are banded in parallel to the rolling direction, and the widths of bands of the two phases change relatively, so if the α-band yields, then the dimension decreases in the direction of the length of banded structure and increases in the transverse direction. When a eutectoid steel bar is heated and cooled, the A1 transformation does not proceed uniformly over the whole of a specimen, the pearlite and γ-phase are banded in parallel to the rolling direction. And the widths of the both bands change relatively, so if the γ-band yields, then the dimension increases in the rolling direction and decreases in the transverse direction. Dimensional changes of medium carbon steel bars due to heating and cooling diminish owing to the above contrary tendencies. In the case of hyper-eutectoid steel bars, the tendency of the above mentioned plastic deformation in the A1 transformation of the eutectoid steel bar is decreased by the existence of primary cementite.
The bainite transformation was studied by examining the surface distortions of various steels during thermal treatments. The relation between the relief structure and etched structure was also discussed. The results are follows: (1) Relief markings were observed during bainite transformation but pearlite did not produce any relief effect. (2) Each relief marking corresponds to the dotted line of carbide in the upper bainte structure and to the acicular structure of the lower bainite. (3) The relief marking due to bainite formation grows slowly and the rate of growth increases as the transformation temperature increases. The calculated value of the activation energy for the growth of the relief marking was about 19,000 cal/mol. (4) The growth rate of the relief marking at constant temperature was independent of the time of transformation. (5) The Widmannstätten figures of ferrite of various carbon and alloy steels produced distinct relief effects.
Thermal dilatometric measurements have been carried out on cold-worked specimens of Cu-Zn and Cu-Al alloys. Several changes in thermal dilatation have been observed in the temperature ranges of anneal hardening. These changes are more pronounced with increase of cold working degree and still more so with higher concentration of the solute. They are considered as anisotropy of cold-worked structure, because their amount is conspicuously larger than may be expected from the changes in density. These changes are also presumed to be due to the release of internal stresses brought about by the preferential migration of solute atoms or lattice defects, which are anisotropically distributed in the cold-worked direction.