The analytical method for radioactive nuclides which contaminate the metal surface was studied. The test specimens were dipped into nitrate solution of the fission products adjusted to pH of 1.4. The radioactive nuclides were removed from the surface by electrolyzing the sample as the anode. ⁹⁵Zr, ⁹⁵Nb and ⁹⁰Y were co-precipitated with the hydroxide of the metals and separated as zirconium phosphate, niobic acid and yttrium oxalate. ¹⁰⁶Ru-¹⁰⁶Rh were precipitated as sulfides from the filtrate, ⁹⁰Sr was determined as its oxalate and ¹³⁷Cs as its perchlorate. From the experimental results, it was supposed that the radioactive contamination with fission products was due to the surface adsorption of radioactive nuclides.

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In recent years, the effect of grain size upon such properties as formability, strength and earing tendencies in 70-30 brass has been recognized to be of significant magnitude in our country. The effects of iron and phosphorus as the added elements on the grain growth in high purity brass were described in the 1st report. In the present paper, the effects of small amounts of titanium and zirconium were investigated after annealing for 4,000 sec at various temperatures or rapid short-time heating at temperatures above 700°C. In the case of the ordinary annealing, titanium is more effective than either iron or phosphorus for grain-size control of brass when present at 0.004% or more. But at higher annealing temperatures, the restrictive effect of titanium was found to be weaker. On the other hand, small amounts of zirconium are exceptionally effective in retarding grain growth even at higher annealing temperatures.

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Practical problems concerning the application of our previous spectrochemical method to routine industrial analysis were studied. The differences and variation of the components between sponge titanium sample solution and spectrochemical standard solution of titanium tetrachloride and hydrochloric acid, and the evaporation of impurity elements during dissolution of titanium sponge were negligible. The time trend of Si% in spectrochemical standard solution was found by observation of relative intensity for 6 months, and its correction procedures are proposed. Various physical properties of carbon electrodes for spectrochemical analysis were determined. The effect of the quality of carbon electrodes on the analytical accuracy and precision was described. Finally, some procedures for expanding the analytical range are described.

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The chemical changes of the metallic chromium during heating in nitrogen or in air were studied. The results obtained were as follows: (1) When metallic chromium was heated in extremely pure nitrogen, a rise of the heating temperature caused a continuous increase in the amount of nitrogen absorbed. The effect of the heating temperature, however, became less notable at higher temperatures, e.g. 1,250°C and upwards. (2) It was found that both oxidation and nitrization took place on the metallic chromium during heating in air. Although nitriding was prevented remarkably by the oxygen present at relatively low temperatures, e.g. 1,000∼1,200°C, it became gradually predominant with the rise of the heating temperature and consequently the increase in weight due to nitriding was about equivalent to that due to oxidation at 1,300°C. (3) The nitrides formed during heating at 1,000°C in nitrogen was identified as Cr₂N and CrN by X-ray diffraction analyses, whereas CrN could not be found at 1,300°C. After heating in air, Cr₂N was the only phase observed to be formed, whatever the heating temperature might be. (4) No marked difference in the amount of nitrogen absorbed by heating in nitrogen was found with the two different samples of chromium employed, i.e. of electrolytic chromium and of thermit chromium. On the contrary, if they were heated in air, both oxidation and nitriding occurred in a greater degree in the former than in the latter.

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The variation of Young’s modulus of 65-35 brass resulting from cold-rolling and annealing has been studied by means of longitudinal-vibration method. The results obtained are as follows: (1) The variation of E resulting from cold-rolling was the same as that of 7-3 brass in all measuring directions. (2) The variation of E resulting from annealing showed various features according to the annealing temperature, the degree of rolling (reduction) and the measuring direction. (3) The anisotropy of E resulting from 30∼40%-rolling disappeared by annealing above the recrystallization temperature. (4) The anisotropy of E resulting from full annealing at 600°C, 700°C, after cold-rolling was different in the case of over 90% reduction as compared with the case of reduction to 80%. (5) The anisotropy of E resulting from annealing after over-90%-reduction was almost the same as that obtained before annealing excepting the case of 450°C annealing. (6) In the case of over-90%-reduction, the anisotropy of E resulting from 450°C annealing was different from that obtained by annealing at above 600°C.

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The effect of small phosphorus additions to sintered permanent-magnet alloys of the MK3 type has been studied, particularly on their densities, magnetic properties, microstructures, and transverse rupture strengths. Additon of phosphorus within a certain quantity markedly improves the qualities of Fe-Al-Ni-Co-Cu alloys prepared by sintering in pure hydrogen. With more than this optimum addition of phosphorus, a phosphorus-containing eutectic appears in the structure of the alloys; this phosphorus eutectic has, however, a detrimental effect on the magnetic properties of the alloys. Within the range of appropriate concentration, phosphorus addition causes grain growth and an increase in density transverse rupture strength, and improvement in magnetic properties.

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The fundamental conditions of photometric determination of tellurium with thiourea in nitric acid solution were investigated and applied to the analysis of cast iron. Tellurium-thiourea complex showed strong absorption at the wave-length less than 400 mμ. Because thiourea itself also showed considerable absorption at less than 345 mμ the absorption at 350 mμ was suitable for the determination. The optimum concentration of nitric acid and thiourea was 6% and 8.5%, respectively. The coloration was completed in 2 minutes and was stable within 10 minutes, and also it obeyed Beer’s law in the range of 0.05 to 0.5 mg of tellurium in 50 mL for 1 cm cell. Preliminary separation of tellurium in the sample was made in 3 N hydrochloric acid solution using stannous chloride. The other elements in ordinary cast iron did not interfere.

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The range near η solid solution of the Cu-Si-Zn system has been investigated by means of thermal analysis, measurement of electrical resistance and microscopic examination. The η solid solution, which is a Cu₃Si solid solution, has two transformations of η\ ightleftharpoonsη′ and η′\ ightleftharpoonsη″. That is, the peritectoids of γ+η\ ightleftharpoonsη′ and γ+η′\ ightleftharpoonsη″ are at 620°C and 570°C and the eutectoids of η\ ightleftharpoonsη′+Si and η′\ ightleftharpoonsη″+Si are at 558°C and 467°C respectively, in Cu-Si binary system. And in the ternary system, the non-variants to ε′+η\ ightleftharpoonsγ+η′, η\ ightleftharpoonsγ+η′+Si, ε′+η′\ ightleftharpoonsγ+η″, and γ+η′\ ightleftharpoonsη″+Si are found at 600°, 530°, 500° and 480°C, respectively. The twin of the solid solution found in the cast or annealed alloys is the annealing twin attributed to the transformations.

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The relationship between the chemical reactivity, or the degree of crystal imperfection and the electrode potential of Zn powder has been studied. The potential difference between a high-purity standard Zn plate (99.99% up) annealed in vacuum and the sample Zn powder was measured potentiometrically both in Na₂ZnO₂ and ZnCl₂ solutions. The distilled Zn powder (D-Zn) is nearly at the same potential as the standard Zn plate, while the electrolytic Zn powder (E-Zn) is the more negative than the standard Zn, the more pronounced the X-ray diffraction broadening in {103}. Exposure to air makes both E-Zn and D-Zn more positive than the standard Zn probably due to the formation of a basic carbonate film. Dissolution of the film brings back their former potential completely.

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The occluded gas in Zn powder was studied by heating in vacuo and analysing the gas evolved by using a mass spectrometer. The results indicated that the electrolytic Zn powder evolved hydrogen in a quantity correlated to the particle size and shape of the powder and also to the degree of the crystal imperfections, which is shown by the X-ray diffraction broadening in {103}. It was also established that the H₂ evolved was not formed from H₂O but from the H₂ occluded in Zn. In the case of Zn powders exposed to laboratory air, the gas evolved by heating in vacuo was composed of H₂, CO₂, CO and H₂O. Of these CO proved to be a by-product from CO₂ which reacted with heated Zn as H₂ was formed from H₂O. It was also established that ZnO alone could absorb CO₂ and H₂O and set free them as such. Thus it may be concluded that the surface of Zn particles, when oxidized, becomes coated with a basic Zn carbonate layer by absorbing CO₂ and H₂O.

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The phase diagram of the system Al-Zn-Mg-Cu (especially in the range of Al-side) has been studied by means of microscopic examination, inverse-rate thermal analysis, electric resistance measurement and X-ray analysis. The Al side of this system is divided into three ranges by the pseudo-ternary systems of Al-ω-CuAl₂ and Al-ω-S, and in these ranges no quarternary intermetallic compound appears. The reactions—ternary eutectic, quarternary eutectic and peritecto-ternary eutectic—in the range of Al-ω-CuAl₂-S and Al-ω-S-T-β were observed as follows:
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The Al-side solubility curves of the Al-ω and Al-ε alloys were lowered by addition of Cu 2% as shown in Fig. 9 and 11.

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The deformation parameter k(Ra⁄Rb, Ra: radius of ellipsoid of deformed G.P. zones parallel to the rolling direction, Rb: radius parallel to the rolling plane and perpendicular to the rolling direction) of various sizes of G.P. zones, which were formed in the quenched Al-30 wt%Zn alloy under the different annealing conditions, were measured from the X-ray small-angle-scattering effects when the reductions of thickness of specimens by cold rolling were 50%. The results obtained were as follows: (1) The values of k are 1.6∼1.2 for all specimens, and these correspond with 37.5∼17.7% reduction of thickness. (2) The value of k for the specimens annealed at 190°C for 1 min and cold-rolled is about 1.5. The values of k for specimens annealed at lower temperatures (room temp., 60°, 80°, 105°, 130°) and cold-rolled do not exceed 1.37, and these values do not depend on the difference of temperature (except 130°C) (3) The deformability of G.P. zones is not affected by their size. (4) These results are the same as the results obtained for Al-Ag alloys, and show that these spherical G.P. zones must be one of the main causes of low-temperature age-hardening.

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The changes of thermal residual stressed in low-carbon steel by quench-aging and repeated stressing were investigated using plate specimens of 0.16%C steel. For the study of the effect of quench-aging, aging at room temperature as well as aging at the temperature 100°C were chosen. In repeated stressing, four stress amplitudes above and below the endurance limit were employed. The aspects of precipitates due to various aging treatments were studied by electron micrographs. The results obtained were as follows: (1) The surface residual stresses decrease first and then increase noticeably, thenceforward diminish gradually both by aging at room temperature and accelerated aging with repeated stressing. In the latter, the increase as well as the fading of surface residual stresses are larger by the higher atress amplitudes. (2) The surface residual stress and the hardness both show their maximum value under the same condition by aging at room temperature as well as by aging at the temperature 100°C. (3) The surface residual stress and the hardness both show higher values by aging at the temperature 100°C for 1 hr than by other aging treatments. (4) In the electron micrographs, precipitates were seen in grobular forms at the early stage of aging and then they grew into plate-like forms. In repeated stressing, their features were quite similar to that of aging, indicating the accelerating effect of aging with repeated stressing. (5) The endurance limit heightens and the life lengthens considerably by this quenching. In this experiment, the rise of the endurance limit was about 53% and that of endurance life was almost 400%. It shoud be noted that the residual stresses play an important role in these improvements.

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The effect of addition of boron or simultaneous additions of boron and titanium on the recrystallization behaviour of cold rolled Al, Al-2%Mg and Al-2%Cu alloys has been studied by means of hardness measurement and microscopy. The results obtained were as follows: (1) The recrystallization temperature in Al and Al-Mg alloy lowered gradually in a slight degree with the increase of the amount of alloying boron till the content reached a certain critical amount, as shown in Table 2. When the content of boron is larger than this critical value, however, the recrystallization temperature becames almost constant. (2) The size of the recrystallized grains become progressively finer with addition of more boron till the content reaches 0.04∼0.05% in Al, Al-Mg and Al-Cu alloys, and also about 0.01% in Al-Ti alloy. In the specimens with boron of more than this content, however, the recrystallized grains are fairly fine and almost constant against the change of final annealing temperature as well as cold-rolling reduction of more than medium degree, also free of influence from the variation of the preliminary annealing temperature. (3) A simultaneous addition of boron and titanium together refines the recrystallized grains of Al more than the addition of boron alone. (4) The recrystallization diagrams for Al-B, Al-Mg-B, Al-Cu-B and Al-Ti-B alloys have been determined, as shown in Fig. 3, Fig. 4, Fig. 5 and Fig. 6.

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When one of the components Ag, Bi, Ca, Cd, Ce, Cu, Li, Misch metal, Sn, Ti and Zn were contained in magnesium as alloying elements, the solubility of Zr in the melt of such a magnesium alloy and the effects of soluble Zr in the molten alloy on the cast structures were studied and the possibility of production of intermetallic compounds by the alloying elements and Zr over the solubility limit in the molten alloys was investigated by X-ray analysis. The results obtained were as follows: The solubility of Zr at 700° was about 0.5∼0.6% in Mg-Ag-Zr, 0.45% in Mg-Bi-Zr, 0.5% in Mg-Ca-Zr, 0.55∼0.6% in Mg-Cd-Zr, 0.5∼055% in Mg-Ce-Zr, 0.4∼0.5% in Mg-Cu-Zr, 0.35∼0.5% in Mg-Li-Zr, 0.55∼0.6% in Mg-Misch metal-Zr, 0.45% in Mg-Ti-Zr, 0.75∼0.8% in Mg-Zn-Zr and considerably decreased in Mg-Sn-Zr by increase of Sn. The grain-refining effect of Zr on the cast structure depended on the quantity of Zr soluble in the molten magnesium alloy. Intermetallic compounds of the alloying elements and Zr were obtained as Mg-Cu-Zr and Mg-Sn-Zr when Zr was over the solubility limit in the molten alloy.

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Studies of the physical and technical properties of Pt-Mo alloys were carried out. The maximum solubility limit of Mo in α-phase (Pt-phase) is 15%, and the lattice parameter of α-phase (f.c.c.) lowers with the increase of the Mo content. Cold-working can be applied to α-phase alloys which contain less than 6% of Mo, and their annealing temperature is above 1,100°C. The oxidation of Pt-Mo alloys has been studied. At high temperature i.e., above 1,000°C, MoO₃ volatilizes away as rapidly as it is formed, and the β-phase transforms into α-phase by oxidation in air. A preferred oxidation of Mo in α-phase was observed by prolonged heating in air, and it oxidized according to a logarthmic-rate law.

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Since the end of World War II, and especially in the course of the latest several years a striking technological advancement has been realized in the iron and steel industry in Japan.
In iron making the attainment of the increase of blast furnace volume, the improved quality of the major raw materials, i.e. coke, iron ore and limestone and the progress of beneficiation method have raised the iron making technique of this country up to the world level. For example, the maximum production of a blast furnace is 1,063 t/day/m³ and coke ratio 612 kg/ton pig. And as the result of repeated tests of oxygen-enriched blast, about 18% of increased production is expected to be brought about.
In steel making the utilization of high purity oxygen remarkably enhanced the productivity of open hearths and arc furnaces without deteriorating the quality of steel, and it has at the same time enabled us to produce extremely low carbon steel, which has been considered hitherto hardly possible by the use of the usual ore smelting method. In the meantime the improvement of the quality of fire bricks and the advanced skill in furnace construction have served to increase the use of oxygen indirectly. The consumption of oxygen has increased in the recent 5 years to 15.7 m³/ton steel from 5.8 m³/ton steel, and fuel consumption has dropped to 730×10³ kcal/ton from 1,004 kcal/ton steel. The introduction of the L.D. type converter, however, has almost revolutionized the steel making methods. In view of the scarcity of scrap resources, in this country, this new method promises to prevail more and because of the superiority its products and the promoted productivity.
As technological improvements in the field of slab-rolling and bar-rolling, the promotion of combustion control method brought about through the reform of soaking pits and reheating furnaces, and the increased capacity and speed in rolling may be pointed out. The fuel consumption has decreased to 150×10³-180×10³ kcal/ton ingot from 200×10³ kcal/ton ingot. The amplification of the dimensions of products by the improvement of rolling mills and the spread of the quality control must not be overlooked as an indication of technological improvements. The advancement in wire-rod rolling equipment is also very notable, by which better quality of products and high efficiency have been attained by means of the high speed continuous rolling method.
In rolling heavy plates, operations far surpassing those heretofore in use in points of the quality, dimensions of the products and productivity is being carried out by using the four-high rolling stand newly equipped to the hithertoused mills. Particularly, the requirements for the carbon steel of improved quality and larger dimensions intended for huge vessels and the plates of high tensile steel (U.T.S.60, 70 and 80 kg/mm²) are getting severer, and the necessary equipments for their rolling, cooling and bettering have been gradually increased in number.
In rolling strips, the strengthening of reheating capacity of hot rolling, the augmentation of rolling capacity by using slabs of larger size, the poroduction of high grade sheets by the improved cooling method have been achieved, and in the increase of rolling speed in cold rolling (1500 f.p.m.-4000 f.p.m.) and the exactness of product gauge by the reformed measuring method of steel plates, a remarkable stride has been made. By operating the continuous galvanizing line and electrolytic tinning line, no small contribution has been brought to the correlated industries in Japan.
The technological advancement in the Japanese iron and steel making summarized above is nothing but the results of the already-published theories applied to as faithfully as possible, and embodied most economically in the actual operation, and further efforts are strongly desired to be made hereafter towards mo

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