Test pieces of various kinds of steels and brass were first subjected to the ordinary repeated impact test at various numbers of repetition without rupture, and then broken by Charpy machine, and the energy required for the break-down and the angle of bend were measured. The relation between the breaking energy and the angle of bend was always a straight line passing through the origin. By the newly proposed theory which the author suggested basing on the present results, a newly defined true breaking strength n bending rupture could be obtned. Also, in tension rupture, a newly defined true breaking strength could equally be obtained by a newly suggested theory based on the straight line relation between breaking energy and breaking elongation.

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The behaviour of a state of cold-working was studied in detail with Al single crystal cold-worked locally. Also, samples of ordinary steel which had been cold-worked (by repeated impact test) locally and annealed at low temperature were studied. The results thus obtained were very remarkable, an intense decrease reaching from 30 kgm to 0.15 kgm being observed. This result is, however, in my opinion easily explained: it is merely an outcome of the general tendency of cold-worked materials. Then, with test pieces subjected to the stress reversals corresponding to S-N curve, the state of cold-working was also studied fully. Thus, a theory on the stability of cold-worked metals was newly proposed by the present author.

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Diffusion coefficients of tin in molten lead have been measured at the temperature range from 450° to 600°. Since the concentration of tin is chosen at a comparatively dilute value in the present investigation, the coefficients have been estimated as constants independent of the concentration. Thus, D=0.0012exp(−5,900⁄RT) is obtained. This result shows that cations of tin diffuse in the molten lead-tin solution, because the activation energy of diffusion is of the same order as in the non-metalic solutions. Finally, the theoretical value of diffusion coefficient, which is calculated roughly by the atomistic theory of diffusion based upon the intuitive free volume model in liquid, is compared with the experimental results.

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Using Boltzmann’s method, diffusion coefficient of tin in molten lead-tin alloy has been determined with respect to many sorts of samples at 510°. A dependency of the diffusion coefficient on the concentration has been observed, through the fact that the coefficient has a minimum, where D=1.7×10⁻⁵ cm²/sec. This fact is closely related to the thermodynamic properties of the molten lead-tin system, which constitutes a positive deviation from Raoult’s law. The change of mobility with concentration is also supposed to cause the same behavior.

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Diffusion coefficients of tin under the existence of bismuth have been measured at 510° in the quasi-binary lead-tin systems. The result shows that diffusion coefficient in this system gives lower value than that of the same concentration in the binary system. This effect can be explained partly as due to the increase of activity coefficient of tin due to the addition of bismuth. This increase is estimated by the use of “interaction coefficient”, of which detailed expression has been already proposed by us.

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A new method of refining crude silicon which consists essentially in electrolysis of the Al-Si anode obtained by alloying crude silicon into molten aluminium as a solvent, has been proposed by the present writers. The principle of the method as well as the results of experimental observations concerning the behavior of the impurities contained in the crude silicon during the process have been described.
According to the experimental results, as a plan for carrying out the present refining method in practice, the flow-sheet shown in Fig. 8 has been found most suitable. The impurities contained in the refined silicon by the present method were determined to be as follows: 0.21% Al, 0.008% Fe, trace of Ca, 0.028% C, 0.001% Ti and 0.003% P.

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After alloying about 3 kg of crude silicon into about 4.5 kg of molten aluminium, the alloys thus prepared have been electrolysed in hydrochloric acid solution. The silicon crystals gathered as the anode slime have been washed with hydrofluoric acid solution and aqua regia.
The purified silicon thus obtained weighted about 1 kg (yield 30%) and the impurities contained in it have been found to be as follows: Al 0.18%, Fe 0.003%, trace of Ca, C 0.022%, Ti 0.001% and P 0.003%, The quantities of several materials, chemicals and the electric power as well as their cost have been estimated in order to produce 1 kg of purified silicon.

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The effect of the roll-temperature, the rolling temperature and the distribution of two phase compounds upon the recrystallization in cold-rolled 2S sheets was studied. The following results were obtained: The recrystallized grains become finer in size and their temperature higher, with the rise of the roll- or slab-temperature, when slab ingots are hot-rolled, even when the conditions of temperature and time of heating prior to the hot-rolling are similar. It is concluded that they are affected by the distributing conditions of two phase compounds, by the investigation of the recrystallization of rapid or slow-solidified ingots.

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A number of studies describing the coarsening textures of face-centered cubic metals have been reported, but no study have been reported concerning the coarsening phenomena in hexagonal-close packed metals. The coarsening texture produced in high purity zinc sheets cold-rolled to various degrees was investigated. The res lts of experiment are as follows: (1) Basa plane poles of large grains growing in the coarse-grained sheet are closely populated within 20∼30° from the center of the basal plane pole figure. (2) But the beviating direction of this poles is not directional. (3) Coarsening textures in zinc sheets with the {0002}⟨11\bar20⟩ texture are, in general, related to the main orientation of the matrix by rotation around the [0002] axis, and the range of rotation is approximately 0∼22°, the textures being frequently the same as the {0002}⟨11\bar20⟩ texture in the matrix. These rotation relationships almost correspond to the case of face-centered cubic metals. (4) Coarsening grains will develope closely connecting with the orientation relationship between neighboring grains shown in primary recrystallization texture, and the produced sharp orientations will depend on the reduction of cold-rolling. (5) Basal plane inclination of neighboring grains is possibly within 10∼30°.

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No study has ever been published describing the preferred orientations developed in single crystals of zinc as the results of systematic cold-rolling treatments. The changes in oriented structures produced are shown in this paper: Several kinds of single crystals of zinc (99.99% purity) having different orientations are cold-rolled progressively to reduction from about 50 to 90%. The results obtained are as follows: (a) At about 50∼60% cold-rolling reduction, four separate non-symmetrical poles corresponding almost to preferred twinned orientations are, in the basal pole figure, added to the pole of ideal rolling texture, (b) and at about 80%, these poles are diffused and changed each other towards the transverse and the central directions respectively, that the central pole showing ideal texture becomes greater in density of crystal population, (c) but at about 90% or more, the texture is again apart from the ideal and the crystals relating to twinned positions have largely but continuously been distributed around the axis of the rolling direction, (d) the {0002}⟨10\bar10⟩ texture is not always impossible as substable one, (e) these structures and their changes are rationalized by the fundamental mechanism of deformation, i.e. slip rotation and twinning of zinc crystals.

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The changes of magnetic properties of mild steel containing 0.06∼0.385% C caused by plastic elongation were investigated. With the increase of the degrec of cold work the permeability of specimen decreasee hyperbolically, the st epness of the slope of the magnetization curve decreasss also and the intensity of external field required to saturate the specimen increases. Increase of magnetic induction due to the action of elastic tension is observed and it reaches to a maximum and then decreases slowly. Ifdenote by σ_c the elastic tension under which magnetic induction of the specimen we takes a maximum value, when the external tension σ_c works on the specimen all the magnatization curves of cold worked specimen coincided with that of the annealed speeimen. The value of σ_c increases by cold working and we obtained the following relation between σ_c and the degree of cold working, ε. σ_c=αlogε+β where α and β are constants depending mainly upon the carbon content of the specimen. Both α and β increased proportionally with the carbon content. If μ₀ is the initial and μ_max the maximum permeability, the following relations were obtained, μ₀σ=k₁, μ_maxσ_c=k₂ where k₁ and k₂ are constants independent of the carbon content. These results coincide qualitatively with the theoretical relation between the initial permeability and internal stress which is deduced by Becker and Kersten, Since there are such regular relations between σ_c and the degree of cold working and between σ_c and the permeability deduced from our results, it may by possible to conclude that σ_c is a measure of residual stress caused by plastic deformation.

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The characteristics of rectification with cuprous oxide rectifiers in which the copper plates contain Sb, Cd, Zn, Ni, Fe, Al, Ag, Au and Pb were studied. The following results have been obtaind:
(1) When Sb is contained from 0.000% to 0.07%, the resistance increases in both directions and the backward character is improved. (2) When Cd content varies from 0.000% to 0.02%, the resistance in the reverse direction decreases but negligibl increaser in the forward. (3) Zn content in copper is very injurious in both directions. (4) When Ni content varies, the forward resistance increases the increase is negligible in the reverse resistance below 0.005% Ni. Cu plates containing Ni over 0.03% have worse characteristics, especially in the reverse direction. (5) Fe in Cu plates has little effects in both direction. (6) Al as impurities has little effects in the forward direction, but in the reverse, the resistance decreases. (7) Ag and Au as impurities improve the character in small contents, while the reverse resistance decreases, so Cu plate Ag or Au content in the plates must be limited to below 0.005%. In these cases, the forward currents at small voltages, for instance 0.4 V, were increased and improved. (8) With Pb below 0.04%, the characteristics improved in both directions and the forward current of small voltages was improved. (9) General discussion has been conducted on impurities in Cu plates such as S, Se, Sn, Sb, Bi, Cd, Zn, Fe, Al, Ni, As, Ag, Au and Pb.

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(i) In the former report, the authors have related that the toughness of 0.8% C steel is improved both by prolonged austempering (350°) and tempering (350°) after quenching. In this report, they have studied these effects more exactly on 0.06%C steel. As a result, it is found that by both treatment, the toughness is improved more and more as the holding time is prolonged unitil the effect reaches a maximum, and after a certain time, it gradualy diminishes. These phenomena, however, are not accompanied by any changes in the hardness or the electric resistivity. (ii) Isothermaly transformed (below Ms point) products have been studied for hardness, microstructure and electric resistivity on 0.6% C steel, and their features have been revealed to be more banitic than martensitic. Furthermore, it is tound that the toughness of these products are superior to that of tempered martensite (treating temperature of both products were 220∼240°).

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In the first and second report, we described mainly our studies on the extrusion force, properties of extruded shells and defects which arose on the wall of shells. Here, we are reporting, as the continuation thereof, our investigation mainly on the crystallographic explanation of the earing behavior and the prevention of earing, while extruding the zinc shells. Above all, the mechanism of formation of ears has been accounted for in terms of the pole figures which are constructed by X-ray studies on both rolled aud recrystallized blanks. We found the best annealing condition of the blank to check ears completely, having consedered the defects previously reported. In addition, we succeeded in progressing the yield, employing the regular polygonal blanks, such as squares and hexagons, for economical profit. The formation of ears owing to the particular shape of blanks has also been explained.

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