Studies were made on several sorts of iron ore, sintered ore and other raw materials for charging into a blast furnace concerning their chemical analysis, chief mineral compositions, mechanical strength, porosity, water-absorption degree, bulk density, and permanent contraction or expansion and dehydration respectively by heating. Especially microscopic inspection was made on minerals of iron oxide, the form of crystals of iron oxide as well as their compositions and structure.

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Ingot moulds are exfoliated locally and flakily at its inner surface in the steel making practice.
The author investigated these kinds of defects by means of measuring the heating and cooling temperature of the ingot moulds after pouring of the molten steel, and its microscopic inspection as well as the chemical analysis were examined.
From the foundry point of view, no peculiar fact was found by several investigations.
It was observed that the exfoliation appeared locally at the bottom side at the earlier stage of its use in the general case, and exfoliated pieces had always a simillar shape and thickness.
In comparison with the microscopic structure of the decomposition of pearlite and graphite or decarburization it was proved that these defects were not caused by "crazing" or growth of the cast iron, but seemed to be influenced by each of heating and cooling conditions that is, the temperature up to 850°C, the position and the time approximately 4hrs. of heating of the ingot mould. At the same time, the chemical composition (especially manganese content) of the ingot seemed to have relation to such exfoliation as aforementioned.
This problem will be reported with results of some other experiments in the next occasion when the succeeding study would have been completed.

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Spheroidal graphite cast iron has many good properties as an industrial material, because of its special type of graphite. Wear resisting properties of this material has been expected to be excellent since advent of spheroidal graphite cast iron. Especially, in a dry wear condition spheroidal iron is said to be superior to other types of cast iron. Much research on the wear properties this material has been made by many investigators in Japan but their opinions about wear properties of spheroidal iron differed from each other and various experimental results were obtained. Naturally, complexity of substantial wearing mechanism and diversity of experimental conditions of wearing tests caused these discrepancies. Accordingly, to permit the wearing properties of the spheroidal graphite iron to be clear, experiments should be made in practical conditions. In this report the authors compared the life of spheroidal iron brake shoes with grey iron brake shoes which had been attached to electric tram cars The results were obtained in which the wear loss by grey iron brake shoe was about three times as spheroidal iron. The authors also made brake tests with the same tram car using two types of cast iron brake shoes which were used in the wearing tests. In brake tests retardation curves were recorded by using a self-recording acceleration meter. From these retardation curves the friction coefficients between brake shoes and tires were calculated in various experimental conditions. Thus the brake·effects of these two types of cast iron brake shoes could be compared. The results were such that the friction coefficient of spheroidal iron brake shoe was larger than that of the grey iron shoes when car velocity was raised up to more than 43 kilometers per hour.

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Burning of heavy oil in gas turbines raises some special problems. Especially, "vanadium attack" is a problem of importance. This report discussed the fundamental experiment concerning vanadium attack and some methods which were being considered for preventing them.
The presence of a small quantity of the vanadium pentoxide or artifical ash, 2mg (5mg) on specimens (15×20×1mm), was sufficient to increase the loss of metal from tenfold to fiftyfold in 100 hours.
It was found that this attack was acceralated with increasing quantity of vanadium pentoxide or artifical ash. Especially, Timken 16-25-6 alloy was attached at 800-850°C very severely.
It was presumed that when this alloy with 6 pct. molybdenum content was oxidized, molybdenum trioxide appeared on its surface, and because molybdenum trioxide as well as vanadium pentoxide which had the very low melting point, fused together with the oxide film, the protecting action of the film was destroyed. In addition, molybdenum trioxide and vanadium pentoxide were the catalyser of oxidizing reactions, and thus the oxidation of the alloy was remarkably promoted.
The protection of vanadium attack would be needed either to render V₂O₅ inert (CaO, MgO etc.) or to provide some new kind of protective layer (ceramic coating etc.) over the materials.
It was found that when vanadium pentoxide was mixed with MgO or CaO, the oxidizing reaction of materials was impeded at about 700°C-800°C, and the materials which had been given ceramic coating showed very excellent results for vanadium attack at 800°C-900°C.

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It is known that the notch strength and the notch toughness are considered to be the important characteristics for constructional alloy steels possessing higher level of strength.
From the results of former investigations, one of the authors found out that low tempering temperature embrittlement of hardened alloy steels which occurred at tempering temperatures of 300-350°C markedly reduced the notch strength of the steels under various testing conditions, such as repeating impact, tensile and fatigue tests performed to see the properties of notched bar.
This report was intended to state the studies made on the effect of testing temperatures, varying from -70 to +200°C on Charpy impact values with two heats of Ni-Cr steels which were oilhardened and then tempered at various temperatures ranging from 100 to 450°C. From the results it was noted that the transition temperature, observed from impact value, was apparently a function of the tempering temperature, and that the tempering within the range of embrittlement caused a higher transition temperature, whereas the tempering at approx. 200°C resulted in the lowest transition temperature. Refering this result to the results of studies made by other investigators, on the influencing factor on low-tempering-temperature embrittlement together with the factors generally affected on the transition temperature of steels, the authors suggested the possible reduction of the embrittlement by improving steel-making process, especially by means of the careful operation in the practice of deoxidation, dephosphorization, nitrogenfixation and grain-size controlling.

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