It is very difficult to process by the usual method the Manchurian mangauiferous ore with the low-grade manganese content, partly due to fine fibrous structure of the ore. However, it is easily reduced on account of its self-fluxing composition.
Magnetic roasting under the oxidizing atmosphere gives sometimes concentrates with about 30% manganese. In order to understand this phenomenon, the ferromagnetic properties of the products from the reaction between the oxides of iron and manganese at temperatures below 1200°C were studied.
Finally a method of utilizing the low-grade ore was proposed. According to the present method the ore is charged to a blast furnace to obtain spiegel iron with about 12% manganese, from which manganese-rich slag through oxidation of the spiegel iron is produced. The production of spiegel iron and its practical aspects were discussed, and experimental studies of the oxidation of the spiegel iron and iron ore on an industrial scale were presented. The authors concluded that the present method is not only technically practicable but also economically possible.

View full abstract

The authors carried out table tests on the silica bricks acquired from some brick making works and measured the specific weight, porosity, refractoriness, especially with regard to the plasticity at 1690°C, at which sillica bricks commonly soften. These measurements were compared with the results from the service rest of a working open hearth furnace. The table test of silica bricks concerning the plasticity was fount to gree well with the service result. It may be applied to presume the quality of silica bricks before using it in service.

View full abstract

Die Eisenerze in Dendoku (Kainantoh) bestehen wesentlich aus Mag neteisenerze in wechselnden Verhältnissen bezäglich des Hämatit und Limonit. Es enthalten in reinster Form etwa 65% Fe, 3%, SiO₂ und verhältnismässig geringen Gehalt an P und S. Die gute Reduzierbarkeit, die in dem fundamentale Versuche, erklärt wurde, lässt die Erze ganz besonders geeignet erscheinen für die Erzeugung von Eisenschwamm. Die Eisenschwämme wurden aus dieser Erze miter Zusatz von Reduktionsmittel, nämlich Holzkohle, Fuschuns Braunkohle oder Anthrazite in Hongay (französische Indochina) durch dem Drehrohrofen, der 8m im Länge und 0.7m im Innendurchmesser hat, hergestellt. Während Holzkohle und Fuschuns Braunkohle gute Leistungen aufgeweisten, bei Anthrazit wurde dagegen es slob in ruassige Zustand verwendet, so hatte es keinen Erfolg. Jedoch es gelang ihm bei Verwendung von Anthrazit. der pulverige und nichtgleich grossen Kornern hat, gute Eisenschwamm der Gehalt an metallisches Eisen rund 80% herzustellen. Mit Rücksicht auf Gebrauch und Beförderung wurden die so erhaltene Eisenschwämme ohne An-wendung eines Bindemittels durch massigen Druck brikettiert.

View full abstract

By comparison of the formation heats of metallic oxides per kilogram, an interesting and unexpected fact was found that tungsten oxides (WO₂ as well as WO₃) are more reducible than the oxides of iron or manganese. The reducing power of the electric final slag is so strong that it reduces FeO or MnO in the metal completely. It was thought that it is possible to gain a refined tungsten steel by adding wolframite (61%WO₃) on to the bare bath and reducing two hours more with sufficient coke (18% by weigh ) under normal reducing slag.
Being based on the abovementioned ideas, 35 times preliminary tests were conducted, and 1.82.4% W steels were melted 10 times in succession with the same 5-ton Héroult furnace of the Honkeiko Special Steel Co., Ltd. The excellent result was summarized as follows:
(1) The mean yield of tungsten amounted to 99.6% (nearly all tungsten was reduced) and there remained only traces in the slag.
(2) All results of the mechanical test surpassed those of their specifications. In case the reducing is preferably 30 minutes longer, the more manganese reduced and the higher tensile strength obtained.
(3) The present direct method of manufacture is more economical and less labourous than the ordinary FeW process. Following the aforementioned researches, the Honkeiko Special Steel Co., Ltd. made success in melting low-alloy tungsten steels with less than 24% W by the present method.
Again, recently the author found by the log sheets a distinct difference in the reduction speeds between Mn and W. At present, the author is expecting future possibilities in the following three lines:
(1) Higher-alloy tungsten steels to be obtained by reducing wolframite. for 6070 minutes and refinig them with a new second slag which contains no ore. ("3 slags process")
(2) Further higher-alloy tungsten steels (high speed steels) to be obtained from the WO₃ manufactured by treating the wolframite hydrometallurgically.
(3) Alloy steels with Mo, Ni, Co, Cu, Cr or Mn to be obtained by the same principle.

View full abstract

The iron ore, w ich contains nickel and chromium, may be taken as resources of the metals concerned. The mechanism of separation of chromium from nickel in the form of chromite with the aid of magnetism was explained, with special reference to the magnetic properties of nickel ferrate and the solid solution of nickel in magnetite.

View full abstract

It is very important to investigate how much the output of open hearth fnrriace Tsteel works is influenced by different unknown causes which have not found satisfactory sohations. The factors which may presumably influence the output are as follows:
(1) Worked days in the year.
(2) The time required for each heat.
(3) The time required for repairing the hearth bank.
(4) The quantity of each heat.
(5) Reformation of the furnace strUcture.
Taking these five factors into consideration, the actual result at a certain open hearth furnace steel works were examined and the influence was shown in tonnage. It was found that the difference between the actual result and the calculated figures was only 1.6%. In conclusion some reflection was made on the latest industrial situation of open hearth. furnace steel works with special reference to the factors (1), (3) and (5) and some remarks were made 'therewith respectively.

View full abstract

Die starke Neigung zum Schieferbruch ist beobachtet in dem Mittel der Stahlblöcke und such in den langsam gekühlten kleinen Blöcke, die am Schmelzpunkt langsam, aber unter 1400°C schnell abgekühlt sind. Im Gegenteil hat der mit Unreinheiten bereicherte Stahl, gegossen in kleine Form keinen Schieferbruch gezeigt. Von dieser Tatsache kommt der Schliass, dass der Schieferbruch in dem Mittel der Blöcke hauptsächlich nicht dutch die Seigerungselemente wie P, S und dergLeichen verursacht, sondern auf das langsam gekühlte grobe Primärkristallkern, das die Diffussion der Unreinheiten hemmt und sich zur Kristallseigerung neigt, zurückzuführen ist. Einflüsse auf die mechanischen Eigenscbaften und Abhängigkeit von Seigerungselmente auf Schieferbruch sind hierbei in Retracht gezogen.

View full abstract

As the cause of red-shortness, it is wellknown that copper metal freed from steel in oxidation penetrates into grain boundary and makes bending cracks on the surface of the steel at high temperatures. In our research of the low carbon steel containing copper content below 0.4% and ordinary commercial steel, we have found the fact that such low copper content is not serious factor, but heating in the strong oxidizing atomsphere is the main factor of the surface cracking; i. e. the oxidation red shortness. Over 1200°C the red shortness of the steel (on an Oelsen bending test machine) recovers and surface cracking diminishes. This suggests the existence of the temperature range of oxygen hot shortness and the authors ascertained the temperature range of the shortness both in hot bending test and hot impact test. Other factors such as sulphur are alsot conside red and heating in te atomsphere of hydrogen or mere prevention of strong oxidation surely makes less cracks.
The surface cracks of the steel containing 0.10.4% copper at the temperature range 900°1200°C may be attributed to the oxygen inclusion of the steel.

View full abstract