The ‘Umklappen’ which is the process of the formation of one martensite (α') needle, takes place in an extremely short time. This process, therefore, must be adiabatic and needs no diffusion of atoms, that is, no change of composition, consequently, when the austenite (γ) is cooled from point X (Fig. 2 and 3). it passes through point C' where the transformation would occur if it were isothermal, and yet the state does not change before the temperature falls to point K, where the entropy of γ is equal to that of α' of the same internal energy.
Moreover since the Umklappen is accompanied by the internal stress which needs some energy (W), it does not take, place even when K is reached, But it does for the first time when U is reached at which the internal energy of γ is larger by the amount W than that of α'.
The larger the stre_??_s is, the lower the temperature of U. Hence the so-called Ar'', point should coincide with the temperature of U of the α' needle having the smallest W, the existence of the temperature range of the transformation as is observed is due to the preserce of α' needles of various values of W. In the case of an extraordinary high cooling velocity, the super-cooling of point U may occur, although it does not occur in the case of the ordinary quenching. The degree of the super-cooling depends upon the activation energy for Umklappen Q', which has the different value for each α' needle in general.
This phenomenon also therefore. broadens the range of the transformation temperature.
Thus the nature of α' formation is markedly different from that of the growth-process as in the case of the super-cooled A₃ or Ar' transformation. It is to be concluded that the Ae'' line has no direct relation to the extension of α side line of A₃ transformation (GPA) in the Fe-C equilibrium diagram.

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The effect of water quenching on initial and maximum permeabilities of Fe-Al alloys in the range of the superstructure (Fe₃Al) have been measured with the forged specimens. The curves of initial and maximum permeabilities to the quenching temperature show generally a maximum range which exists in the vicinity of the temperature of super-lattice transformation; the latter curve has another maximum, range which situates in the higher temperatures. The initial permeability of an alloy_??_containing 13.92% aluminium reaches 3500 when quenched from 550°, and the maximum permeability of an alloy of 15.29% aluminium content, 34300 when quenched from 700°. The smallest value of hysteresis loss and coercive force obtained by the present experiment is 68 ergs/cm³ and 0.03 Oe respectively; the highest value of speific resistance is 144μΩ/cm³. From these facts, it is easily understood that the magnetic of iron-aluminium alloys are improved when quenchedl from the of transformation temperature as in the case of permalloy; these alloys may be used instead permalloyaccording to circumstances. Thus thel present investigators have named. these alloys “Alperm”.

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According to literature, the oxide on the surface of iron obtained by heating in the gas furnace has no preferred orientation, while that obtained by the electric-furnace heating has an orientation, in which the (101) plane of α-Fe₂O₃ being parallel to the substratum. Why does this orientation appear in some cases and not in the others ? The present paper deals with this problem. Using the pure iron oxidized at medium temperatures (300-400°) the experiment was carried out chiefly by the method of electron diffraction. The following results were obtained; (1) When iron is heated in air, it becomes, at first, to be coverd with the film of the oxide α-Fe₂O₃ of no preferred orientation, and then powder appears above this film. The powder is also the oxide α-Fe₂O₃ which has the above-mentioned orientation. The degree of orientation becomes remarkable with the growth of the powder. This orientation has no direct relation to the beating atomosphere. (2) It was concluded from the experimental facts that the oxide of the powder state was formed by the oxidation of iron atoms diffused through the oxide film. (3) Even a very small quantity of the oxide powder formed on the film can be detected by the existence of the preferred orientation by means of the electron diffraction.

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Though the electric conduction of molten alloys is mainly an electronic nature; the electrolytic conduction is also recognizable under high current density of direct current. So the composition of the alloys becomes different in the vicinities of the anode and the cathode. In this paper the relations between the electrolytic effect and various factors are studied, such as temperature, time, current density, and the composition of the alloy of Sn-Pb.
For example, 40% Sn in weight, under the current density of 600 A/cm², at 400°C for 4 brs., the Sn atoms migrate to the cathode; that is the concentration of Sn in the anode is 33.04% and that in the cathode is 46.53% so the difference is 13.49%.

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The Influence of Mo up to 7%, P up to 0._??_% respectively on the carburization of steel were studied. Mo has but slight influence on the degree of carburization while P retards the carburization. The austenitic grain size of steel including Mo is very fine, so the addition of Mo is apt to form abnormal structure. P has a tendency to graphitize the cementite.
By utilizing magnetic analysis, the nature of carbides in carburized specimens were studied; in Mo-steel the magnetic change of ferromagnetic carbides takes place at about 200° d 400°. The former is due to cemcntite while the latter is double carbide. Mo has fair solid solubility to cementite while P has none.

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The authors carried out a series of experiments with four varieties of spring steel, i.e. two Si-Mn steels, Si-Cr steels and Mn-steel. Changes in these mechanical properties brought about by different heat treatments, and in transformation points due to cooling velocity were measured.
The results of this study may be briefly summarised as follows:- (1) Elastic limits of each steels are not very different. (2) Elongation and impact value are maximum in the Si-Mn steel, but lower in the Si-Cr steel. (3) Rates of proportional limit, elastic limit and yield point to tensile strength are changed by the tempering temperature; moduls of elasticity are slightly effected by tempering temperature. (4) Resistance to bending is largest in the Si-Mn steel, while that of Si-Cr steel and Mn steel become large in some tempering temperature.

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We investigated the hardness and toughness of band saw steel due to tempering after being quenched. Isothermal treatm ent was made on the high class carbon steel containing 0.8_??_1.1% carbon which is made from magnetic sand and of the steel, containing a little nickel and chromium as a band saw steel.
The rockwell hardness of steel is 40_??_45_??_ the impact value of tempering after, quenched is larger than that of isothermal treatment. But if the steel is properly cold rolled after heat treatment, the impact value of isothermal treatments is excessive rather than that of tempering after quenched. The steel is ascertained to be most adequate as a band saw steel.

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When the round bar was once stressed by tension or torsion to the neighboring point of its yeild point, the fatigue strength was not changed, but provided that the round bar with a V-type groove was once stressed to the neighboring point of its yield point, the fatigue strength was decreased when the applied force was torsion and increased when the applied force was tension.

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The formation of complex ion in NaCl-PbCl₂ solution increases the polarization, but compact lead does not separate out. At low current density separated lead becomes more compact. Owing to the formation of PbCl₂ film at the anode it changed to the passive state and the voltage necessary for electrolysis increases alove lOV.
When an insoluble anode is used, Pb (OH)₂ and H₂ gas are produced at 2.8 V on the cathode. The pH of catholyte remains almost unchanged, but anolyte becomes acidic due to the production of Cl₂ gas. In this case separated lecd is spongy. When diaphragm is used, current efficiency increase up to 85%.

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I have investigated about the appearance, thickness, weight, scratch hardness, and anticorrosive properties of colored pure copper relating to coloring conditions in the solution of many kinds; such as copper nitrate solutions, copper acetate+ammonium acetate solution etc.
The sesults of experiments are as follows:
(1) The effects of pH, time, temperature and number of dipping of coloring solution upon the appearance, weight, thickness and scratch hardness of films were explained.
(2) The processes of generating of films were explained.
(3) The anticorrosive properties and effects of sun light upon the appearance were studied.

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White castirons composed of 2.4% C, 0.20% Si, 0.2% Mn, 0.05% S, 0.07% P, O.05_??_0.5% Al, 0_??_1.0% Cr, and 0_??_3% Ni were cast into chill mould, quenched, and annealed; Their graphitizing behaviours were examined under a microseope and by the hardness test. In the quenching temperature range of 780°_??_950°, the higher the quenching temperature, the larger the cooling rate is, and the easier becomes the graphitization by the subsequent annealing. The graphitization is remarkably promoted by both quenching and the addition of 0.2% Al. The further addition of alumimum gives only a little perceptible promotion of the graphitization. Nickel also promotes the graphitization of cast iron, although the recondary graphitization of 0.2% Al-3.0% Ni cast iron is returded due to the lowering of the Ar₁ transformation range by the addition of nikel. It is interesting that the part plastically worked by the indentor of hardness tester is easily graphitized.- the refinement of the cementite particle caused by the plastic deformation results in. the extension of its surface area, and the graphitization is easily achieved by the subsequent annealig; hence there follows the graphitization of the part plastically worked even when the other part is not graphitized.

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Quantitative emission spectral analysis of berylium contained in a solution; whose concentration as metal is between 0.03 and 0.001 per cent., was studied by using a newly deviced liquid electrode applying the combination of a cup of platinum crucible and an iron salver as shown in Fig. 1.
Berylium in a liquid solution acidified by nitric acid either in copper or in aluminium was determined basing upon the ΔS of the live pairs of Be 3131.1/Ca 3158.9 Å and Be 3131.1/Cd/3250.2 Å. Here calcium was chosen as the internal standard and cadmium as the coupling electrode. The analytical accuracy ranges were from ±4.45 to ±7.32 per cent., in this procedure.

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