(1) We considered fusion of iron and vaporization of molten iron from rate process theory.
(2) Advantages of mathematical statistics were shown in adjustments of matters in steel making operations.

View full abstract

In the steel casting foundry, properties of the steel which satisfy tbe casting are hitherto been neglected, but for manufacturing the good steel castings the properties of the steel are very important. And melting practice whicl satisfies these properties is necessary. Properties which are demanded for the steel castings are as follows:
1. Free from blow holes, pin holes.
2. Safety for the hot tear.
3. Good fluidity.
4. Mechanical property.
5. Good. weldability.
These properties are satisfied by the melting practice under the conditions.
1. Elimination of H₂, O₂-
2. Control of the composition.
3. Control of the temperature of the molten steel.
So that, the melting of the steel castines by the basic electric furnace should be differ from that of the ingot making. And following should be demanded.
1. An object of the oxidizing period is to eliminate H₂.
2. Moderate decurburizing speed should be necessary and other composition should not be decreased as possible.
3. Deosidizing should be forced as possible in the deoxidizing period.
4. Consequelltly. non metallic inclusions are allowed unavoidably.
5. S should be decreased as small as possible to avoid the hot tear.
6. Mn should be added much more than the quantity which needed for the deoxidation to prevent the hot tear.
7. Elimination of the gases in the molten steel is the most important which decide the fini-shing condition of the steel.
8. Tapping temperature should be higher than 1520°C.

View full abstract

(1) In case the time of sand mixing with the additional clay is constant, it is less effective to add such amount of additional clay as becoming a washed clay.
(2) In view of enhancing the effect of additional Clay, small grain of the raw sand itself sball be removed.
(3) Even increasing the time of sand mixing, the sana grains would not be broken in proportion thereto.
(4) In case sand mixing takes a long time it shall be performed after small grains have been removed just like in the case of (2).

View full abstract

In this experiments the action of outer stress for the flake-like defects formation is studied.
(1) The effect of outer stress stressed before the pickling on the number or shape of defects is not so clear.
(2) The effect of outir stress stressed after the pickling and just before the breaking is not also clear. But from this experiment it is confirmed that the effeot of small inner notch is important for the flakb-formation.
(3) The quenched and tempered test pieces of various steel in pickled under the outer stress. It is confirmed that the flake-like defects is appeared during the pickling under the stress larger than the definite value.
(4) From this results, it is supposed that the existence of outer stress larger than the definite value would be essential for the flake formation with the supersaturated hydrogen in steel.

View full abstract

The structure of the scale of the Fe-Al, Fe-Cr-Al and Fe-Si alloys was observed.
The relation between the thickness of each layer of the scale and aluminium content when the Fe-Al alloys were heated in the air at 1200°C for 1 hour, were shown in fig. 1. The chemical compositions of the I, II, III and IV layer were Fe₂O₃, Fe₃O₄, FeO and FeO·(Fe, Al)₂O₃, respectively. The Fe-Al alloys produced α-Al₂O₃ film on their surface. On the Fe-Cr-Al alloys which contained comparatively small content of aluminium and Chromium, the three layered scale which was consiste of Fe₂O₃, Fe₃O₄ and FeO·(Fe, Cr, Al)₂O₃, was produced. The thickness of the scale of the Fe-Si alloys was shown in fig. 6 with reference to silicon content. The scale of the Fe-Si alloys lower than about 3% Si, was consisted of four layees Fe₂O₃, Fe₃O₄, FeO and Fe₂SiO₄ one. On the surface of the high silicon alloys, SiO₂ (β-tridymite) film was produced.

View full abstract

The author carried out the experiments with three varieties of spring materials, i.e. Si-Mn steel, 13% Cr steel and W-Cr steel for parallel slide gate value at high temperature and pressure.
The experiments were carrid out the measurements of tensile test, hardness, microstructure, compression test at room and high temperature at about 500°C.
The results of experiments were concluded that the best spring material was W-Cr steel.

View full abstract

The author carried out a series of experiments on the effect of 0.3-1.0% V for three kinds of 0.19, 0.23, 0.28% C tool steel for hot working contaning low tungsten -chromium, and studied changes in their hardness brought about by different heat treatments, and then hot hardness and impact value are also measured.
AS the results of this investigation, it is ascertained that the steel containing C 0.2-0.25, Cr 2.5, W 5% are most moderate in containing of 0.4-0.7% V for hot working operation.

View full abstract

In Japan integrated iron aad steel plants being located near sea ports it is convenient to import their raw materials and export their products.
In the States our attention is especialy paid to the yield problem, while in Japan 30-40% in case of plate and 40% in wire rod is cut away and wasted. This will never happen in the States.
I hope I can send an expert engineer in this line from the U.S.A. when I go back home.
I think it will become very difficult to keep up small non-integrated plants in future. Electric furnace operation uneconomical to be used for making pig iron or steel ingots.
Production schedule should be made by the demand. Plants should be kept always clean so as to ensure good products.
Japan must promote export industry especially of iron and steel to cover her lost market for silk. Japan has enough capacity of open hearth, blast furnace and rolling mill to meet the demand by Philippines, Australia and India for Japanese products, especally for galvanized sheet.
To promote export it is essential to make goop products enough to meet the specification of customers.
One of the important things for the industry is to reduce the cost.
After 10 months' survey of the industry in Japan I discovered that expensive items are coke and labor. The labor expense for blast furnace operation is nearly 2 time higher than that in the States. To cut down the coke price the mining should be made efficient with mechanized equipment and curtailed labor. As the coal price has a grave influence on all economic field, every possible effort should be made to bring the price down.
Also the importation of coal should be decreased and Japanese coal be utilized to the full.
The mixing method of various kinds of coals as will as the utilization of coalite should be studied. Although I do not have any objection against the importation of coal, I think the funds should be used for more necessary items, and importation should be made with careful consideration.

View full abstract