The strength of coke produced in coke oven is increased by means of washing at the Works' washery. The effect on coke property is due to the following actions: By washing, coal becomes uniform in its composition and more finely crushable by the disintegrator. These were observed through measuring ash content and size fraction of charge coal. Beside it is removed of the constituent weathered during storage, it was proved by humic acid and other chemical analysis at the weathering test of Hokkaido coals.

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The basic components of slags as CaO, FeO, MnO, et al. forsake O- and give it to the complex anions SiO₄^4-, Si₂O₇^3-, PO₄^3-, et al. that are a part of the acidic components as SiO₂, P₂O₅, et al. The basicity was refined anew from the consideration of binding energies and was related to the Martens scratch hardness of 28 kinds of slag samples. This relation was found to be nearly exponential. Now other kinds of slags are considered more accurately.

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This paper deals with the graphite formation at the freezing range of cast iron, as the form and distribution of graphite is mainly influenced by the time kept at the freezing range.
Quench tests from various higher temperatures were made for normal gray cast irons and for cast irons which were treated with magnesium.
It was shown that both flaky and nodular graphite are formed directly from the melt when the iron is cooled down to the eutectic temperature.
In the case of nodular graphite cast iron, following facts were shown;
The velocity of graphite formation is much smaller as compared to normal gray cast iron.
When the magnesium contents is more than the requisite amount (for example 0.06% for some composition) nodular graphite can be formed only at a slow cooling rate. If the cooling velocity is not slow enough, white cast iron is formed.
Magnesium treated iron which has aquired the ability of nodular graphite formation, does not lose its ability, so far as the magnesium content is more than the requisite amount.
Therefore, if the magnesium treated iron is solidified and remelted under a non-oxidizing atomosphere, the nodular form can be reproduced.
When the remelting temperature reaches as high that magnesium is easily volatilized, the ability of nodular formation is gradually lost, even under the non-oxidizing atomosphere.
The authers have the opinion that magnesium treated iron has a plenty of graphite nuclei in the melt, but the cementite is stable and the graphite is difficulty to grow, and these condition relate to the nodular graphite.

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Synopsis: In order to obtain suitable colour on the surface of high carbon steel, when it was quenched, the sample was treated in the weak oxidizing atomsphere at various conditions, and the colour was measured with the Fujii's colorimeter.
The results are as follows:
1) As the oxidizing power increases, the colour varies from yellow to blue.
2) The reddish purple coloured sample has less content af white and more content of black than other coloured sample when it is measured with the Fujii's colorimeter. The rate of colour variation is maximum in the part of reddish purple.
3) When the sample is more excessively oxidized, its colour becomes all weak blue, and no other colours appear.

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According to a theoretical consideration about the solution and diffusion of hydrogen in steel, it is shown that the solution coefficient is expressed as
K=K₁ Te-T₁/T
and that the diffusion coefficient as
D=D₀ e-T₂/T
Then each constant is determined by the readjustment of the former researched results. A calculating chart for the remaining rate of hydrogen in the steel heated at constant temperature is worked out from the above-mentioned expressions; and these are ascertained to be useful for investigating semi-quantitatively into the behaviours of hydrogen in steel, as a result of comparing calculated values obtained by the chart with observed values concerning diffusion.

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Following the 1st reports, the author studied on the experiments with four varieties of spring materials i.e. Si-Mn steel, 13% Cr steel, 10% W-Cr steel and W-Cr-V steel, for valves at bigh temperature and pressure.
The experiments of the spring materials were carried out the measurement of forginability, hardness tensile test, microstructure, compression test at room and high temperature at about 500°C. The results of experiments were concluded that the best spring material was 10% W-Cr steel, and next was W-Gr-V steel. (18-4-1 type.)

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The resistance for temper softening of special steel are effected by the composition and its heat treatments. A series of experiments has been carried out to study the effect of each elements of tool steel for hot work, i.e. C 0.3%, Cr 2.5%, W 10%, V 0.3% on the resistance of temper softening and softening for high temperature, and then comparison to the other tool steel, high speed steel and heat resisting steel.
As the results of this investigation, there are ascertained moderate contents of each elements for tool steel for hot work.

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Comparing with other methods of determination of Mn in iron and steel, the estimation by measn of As₂O₃ solution is not only, quicker and economical, but also yields rather good results, so it is widely adopted as routine analysis in numerous plants. Though rapid and simple, it has, on the other hand, several defects as causing analytical errors, and there remain many points still to be cleared, in consequence of incompleteness in the theoretical explanation and the method of confirming the mechanism of reaction. In the present investigation, therefore, every condition of operation is carefully studied, and the best ones found are as follows.
(1) The time of boiling after adding (NH₄)₂S₂O₆ shall be limited to a minute. (2) The temperature of the solution at the time of titration shall be below 30°C. (3) The shorter the time required for titration is, the better is the result, but ordinary titrating velocity will do too. (4) AS regards the concentration of acid for dissolution, 30 c.c. of HNO₃(1:1) will do as shown in Gakushin Method, but the use of H₂SO₄ at the same time in more rational for certain kinds bf samples in view of the sluggishness of dissolution velocity thereof. (5) The most suitable amount of AgNO₃ to be added is 10 c.c. of 1% solution, and (6) that of (NH₄)₂S₂O₃ is 10c.c. of 25% solution just as in customary practice.

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