The beginning temperatures of separation of α or Fe₃C from austenite are represented by super-solubility curves G₀S₀ and E₀S₀ respectively and not by solubility curves. The idea of super-solubility curves were discussed and applied to explain the Ar₁ transformation mechanism and the following results were obtained: When the steel was cooled from austenite range so show that the equilibrium state is established, (1) eutectoid reaction occurs not at the point S but at a temperature lower than S, which is the point of intersection of the lines GS and E₀S₀ (2) pearlite is produced from Fe₃C nucleus, (3) pearlitic structure appears only in hypo-eutectoid steel and not in hyper-eutectoid. steel, (4) “abnormal structure” appears only in hyper-eutectoid steel and it is an intermediale structure, which appears when the temperature was lowered before the equilibrium was established in the temperature range between PSK and P₀S₀K₀.

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The mechanisms of austempering of steel were discussed and the structures of austempered steels were explained as follows: (1) Pearlite is a decomposition product of γm in the temperature range, in which the growing Velocity of Fe₃C is faster than that of αm (2) Bainite is a decomposition product of γm in the temperature range, in which the growing velocity of αm is faster than that of Fe₃C. (3) Upper bainite is the bainite in which the Fe₃C separated out primary γm and lower bainite is the bainite in which the Fe₃G separated out secondary from αm.

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The weight-decrease as well as the decreases in tensile-strength and elongation of aluminium containing Fe, Si and Cu after immersed into NaCl (3%) and HCl(1/2N) solution have been measured. In general, the addition of Cu is most harmful for corrosion followed by the addition of Fe; the effect of Si is not so serious, As the corrosion of aluminium containing Cu belongs to the “Pitting-type”, the decrease in tensile-strength, especially in elongation is always very conspicuous compared with the weight-decrease.

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In order to improve the corrosion, resistance of 98% aluminium, containing 1.2% of iron. and 0.8% of silicon, magnesium, manganese, antimony, and silicon were added to the aluminium, and the weight-decrease as well as the decrease in tensile-strength or elongation of the alloys after being immersed into various corroding medium, have been measured.
For 3% NaCl solution, the addition of magnesium up to 3.5% is most effective followed by the addition of manganese (up to 1%) or of antimony (up to 0.5%).
For 1/2N HCl solution, the addition of antimony showed the best results followed by the addition of magnesium (up to 3.5%). The addition of manganese and silicon, however, showed negative effect for this acid.
For 1/2N NaOH solution, all of the additional elements showed no good results.

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By the impact-test the effect of N₂ on the temper-brittleness in carbon steels and low manganese steels containing nitrogen was investigated.
Specimens containing different amounts of nitrogen were made by addition of nitrified manganese in required proportions. AN specimens were quenched from 950°, tempered at temperatures from 400° to 650° for 1 to 3 hours, and water quenched or furnace-cooled.
Then the impact-value and vickers hardness were measured. From the present investigation the following results were obtained. That is,
a) The temper-brittleness in medium carbon steels appear by the addition of 0.01% nitrogen and is markedly observable as the nitrogen content increases.
b) The temperbrittleness is not affected by manganese content but increases with nitrogen content.
c) This phenomenon is due to the solubility change of nitrogen in a-iron at temperature lower than about 580°.
d) On heating at. temperatures higher than about 580° the brittleness decreases with the increase of holding time.
e) The impact value of specimens tempered at 600° or 650° and water quenched decreases with time by aging at room temperature probably owing to the carbon.

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we studied the boron on steel by the electrolysis A fused borax, using steel as cathode on which boron waa deposited.
The results of experiments were as follows 1) The cementation occumed at so low temperature as 800° and above 900° it increased expnnemiall with tomperature.
2) When 0.15%, steel was cemented for example at 900° and 10 Amp/dm² for 2 hrs, the thickness of the cemented layer was about 0.1mm and the hardness of the layer was so high as approximately 1200 Vickers hardness.
3) W, Mo or V etc. added to steel retarded the cementation of boron on iron, and C, Ti, Si, W etc. increased the hardness of the cemented layer.

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Fe-Ni alloys were obtained by electrolysis from a solution containing sulphates of both metals and ammonium sulphate. The PH value was controlled with acetic acid. We investigated the relations between compositions of solutions, temperatures, current densities or electrolysing duration and compositions of electrodeposited alloys.

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Some residua stress versus depth curves of heat treated steels are smooth while the others show minimum poiuus. the occurrence of the minimum pint in the curve is attributed to the unequal temperature of the Ary, Ar' or Ar'' transformation in the specimen when its dimenxious is large, or when its composition is not uniform by decarburizationr or carburization. The minimum point moves toward the center or surface of the specimen according to the carbon concentration or the treatment. These facts are shown in this report.

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The heat resisting steel is hitherto widely used in mechnical and chemical industries, being chiefly applied too internal ctombusinn engines. Picking up thirteen different kinds of heat resisting steels, the writers first examined their mechanical properties at room and high temperature, and brittleness due to heating in high temperature, and then tested the resistance to oxidation in high temperature.
As the resalts of this investigation., it was found that the steel containing high nickel and chromium content are naperier to other steels and high manganese-chromium steel containing a little vanadium or nitrogen are used as a substitution to high nickel-chromium steel for atemperature of or nea 800°, and high chromium steel containing silicon are most proper for use as an inlet valve of internal combusion engine.

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In this report the properties of anodic films of Al-alloys are studied. The results obtained are given in Table 1, 2. and Fig. 1, 2, 3 and 4. The characteristics are as follows:
(1) An, dic films have good bearing properties.
(2) The film consists of three layers and the hardness of these layers have each alue.
(3) On the hardness of Aluminium alloy's film:-
i. Al-Mg, Al-Zn alloys have hard film and increase by these content in aluminium.
ii. Al-Si alloy does not change by its content.
iii. In Al-Cu alloy the film becomes very hard by the vapor treatment, but softner than the Al-Mg and Al-Zn alloy's film.

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In this report the effects of thin metalic or non-metalic film on the bearing surface are studied. The results obtained are as follow.
(1) The oxide film on the Pb-Cu bearing alloy proofed its anti-seisure property.
(2) Soft and low melting point metals as Pb and magnolia metal are effective to decrease surface friction.
(3) Other chemical compound film as AgCl has also, anti-friction property.

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The writer has already ascertained the effect of each elements on the molybden-tarigsten high speed steel containing W3%. Mo 6% and its suitable conrposition.
Moreover, the writer carried out a series of experiments on the effect of each elements. i.e. C 0.7-1.2, Cr 3-6, W 0.5-2.0, Mo 3-6 and V 0.5-3.0% for standard composition containing C 0.85, Cr 4, W 1, Mo 5 and V 1.5%, and studied the changes in their hardness and microstructure brought about by different heat treatments, and also tested their cutting durability patting tiem in actual service. As the results of this investigation, there are ascertained that The steel containing C 0.8-1.0, Cr 3.5-5.0, W 1-2, Mo 4-6, V 1.3-1.8% are of suitable composition and when quenched from 1250-1300° and tempered at 550-580° they as suitable for heat treatment.

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Although a number of investipators have studied the change of the physical properties relating to the eutectoid. transformation and. artificial aging of some alloys, little attention has previously been given to above said phenomenon by means of the twisting machine. For that purpose, a simple twisting machine was designed by one author, which is shown in Fig. 1. It consists of two part; One is the vertical-typed twisting machine with a controlling spring to keep the balance between the pulley and the counter weight, which is given the simple twisting moment to the specimen. The other is the electric furnace which is cvered with an aluminium plate in order to eliminate the loss of heat. The test piece has the demension of 5mm diameter and 30mm gauge length. The present results coincided with that obtained by other investigators.

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Quantitative emission spectral analysis of boron contained in a liquid solution, whose concentration ranges between 0.015 and 0.15 per cent., was studied by using a new type liquid electrode. The amount of boron in a solution acidified with hydrochloric acid was determined from the AS of the line pair of B 2497.7 Å/Zn 2502.0 Å using zinc as an internal standard. The analytical accuracy in this procedure was ±4.36 per cent.
The method was applied to the determination of boron in tourmaline and some hot-spring waters of Akin, Miyagi Prefecture.

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In view of the inherent advantages of the so-called “Internal Electroanalysis” it is quite interesting to apply this mechanism for the determioation of coprer in iron and steels. In the previous works concerning this method, the stick or plate of metals were used as an anodic electrode. The present author has substitnted it by the liquid amalgams as have been reported by many authors. In this paper, are reported the results obtained from the following;
(1) On the influences of a forign metals on the determination of copper in iron and steels.
(2) Application of the results thus found to the actual analysis of iron and steels. Analytical procedares for each kind of materials are also proposed.

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Investigations were made on the abrasion, galling phenomenon at high temperature and corrosion resistance of the following materials of value seatings to the solutions of 3% NaCI, HCI, H₂SO₄, HNO₃ solutions in various concentrations.
(1) Co-Cr-W series.
(2) 18% Ni-Si-Mn-Cr series cast iron.
(3) 13% Cr steel etc.

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