Tetsu-to-Hagane

CARACTERE DE LAITIERS FONDUS CONTENANT L'OXYDE DE CHROME A HAUT FOURNEAU

Yukio Matsushita

1956 Volume 42 Issue 10 Pages 945-950
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_945

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En ayant pour but de rechercher comment l'oxyde de chrome se conduit-il dans les laitiers fondus à haut fourneau, nous avons preparé les échantillons des laitiers comme suit et nous avons mesuré le longeur d'onde λ_m dans le domaine visible correspondant au maximum de pénétrabilité par le moyen de spectrophotomètre. Alors nous avons fondu et refrigéré en forme vitreuse sous vide en ordre de 1/1000mm Hg le système quaternaire de CaO-SiO₂-Al₂O₃-l'oxyde de chrome préparé synthetiquement, duquel chaque feuille transparente a été decoupée.
Dans ce cas les essais ont ete faits par la méthode de "3×3 Latin carré" avec la composition des laitiers de 15% Al₂O₃, 3% Cr₂O₃ et 0.8-1.2 CaO/SiO₂, ainsi que la température maximume de chauffage et l'heure maintenue limitées comme 1360-1400°C, 2-6h respectivement.
Ainsi nous pouvons conduire les conclusions suivantes.
(1) Dans ces laitiers fondus l'oxyde de chrome prend la forme prédominante de CrO stoichiomètriquement, parce que les échantillons réfrigérés sont de couleurs bleues, mais en même temps un peu vertes.
(2) Ce système expérimental est arrivé à l'état stationnaire, et l'oxyde de chrome se comporte comme l'un acide ou l'autre basique ep accord avec CaO/SiO₂, soi-disant la basicité des laitiers, prenant les valeurs plus d'un ou moins d'un respectivement, parce que λ_m déjà exprimé augmente avec l'accroissement de la basicité.
(3) Ensuite, au contraire, λ_m diminue avec l'augmentation de la température de chauffage. Ce fait dépondra de la décroissance de pression partielle d'oxygène dans l'atomosphère.
(4) Nous pourrions avoir la connaissance intime au lien des silicates fondus, si nous examinions en moyen ici pris les manières des atomes transitoires de quelques valences, par exemple, fer, manganèse, titane, vanadium et ainsi de suite.

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AERODYNAMIC CONSTITUTION OF OPEN-HEARTH FURNACE (I)

INTRODUCTION

Hidefumi Hashimoto

1956 Volume 42 Issue 10 Pages 950-955
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_950

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From the view point of productivity, improvement in open-hearth furnace means shortening the time for each heat and keeping high production rate for a long period. Productive characteristics of open-hearth furnaces are expressed in formulas using the characteristic constants K (the latent production rate at initial state) and a (the decline of production rate per production of unit amount), which make it possible to compare a variety of opeo-hearth furnaces each other as to their productivities.
Many factors affect K and a, they are mainly related to types and arrangement of the following constotuents.
(1) The checker chamber, the fantail and the slag pocket
(2) The air-uptake and the end wall
(3) The furnace head (end roofs, dog houses, side walls and throats)
(4) The fuel jet
(5) The furnace chamber (ceilings and walls).
In studying the factors throughly and extensively to improve open-hearth furnace rationally, it is more easy, more efficient and less expensive to study them by means of smallscale models. Model experiments under suitable considerations represent phenomena in actual furnaces satisfactorily.
When an open-hearth furnace or other furnaces are built, they willbe designed rationally by the aids of model experiments. The method is not a quite new one, but it has been applied as an indispensable procedure in the case of aircraft or ship building.

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STUDIES ON THE INGOT MAKING PROCESS IN NITROGEN ATMOSPHERE (I)

Jenichiro Takao, Takaaki Shimose, Katsumi Saito

1956 Volume 42 Issue 10 Pages 956-961
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_956

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This paper compares results of the nitrogen blowing process with the ordinary and floating boards process for prevention of molten steel from oxidation in pouring process. Results obtained are summarized as follows:
1) Floating boards are not much effective.
2) Nitrogen is effective.
3) Oxidation of molten steel in ingot molds cannot be neglected from consideration of scum formation in ingot molds.

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RESEARCH ON THE NON-METALLIC INCLUSIONS OF KILLED STEEL (I)

Yosaku Koike, Sahei Noda

1956 Volume 42 Issue 10 Pages 962-968
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_962

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The microscopic and macroscopic non-metallic inclusions concerning the practical killed steel-ingot of 5 tons were investigated. The results obtained were as follows.
(1) Microscopic inclusions
(i) The microscopic non-metallic inclusions in the practical ingots changed their apperances corresponding to the positions in them (so-called, top or bottom). The cleanness and thickness of inclusions observed in the practical billets were different from those in the 2kg sample-ingot taken under the ladle.
(ii) The conditions of the inclusions were not influenced extremely by the change of pouring method (top-poured or bottom-poured) and Al-amount added in the ladle.
(iii) By observation of the maximum sizes of A-type (elongated) and B-type (not elongated) inclusions about both samples, taken under the ladle and from the practical billets, A-type inclusions showed a large difference between both samples, but B-type were nearly the same.
(2) Macroscopic inclusions (streak seams)
(i) When 430g/t Al was added in the ladle, at top pouring the Al₂O₃ type seams were found at the ingot-bottom and within the end of columnar crystals. These seams decreased, when 220g/t Al was added in the ladle.
(ii) The tendency of distribution of these seams in the bottom poured ingot was not so clear as the top poured ingot.
(iii) The rate of occurrence of these seams between the ingots of the same charge was influenced by the teeming velocity and other conditions of the ingot-making.
(iv) The rate of occurrence of the seams increased, when the molten steel was viscous by the effect of low temperature or other causes.

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THE DIMENSIONAL STABILITY OF BALL BEARING STEEL (II)

Takashi Hattori

1956 Volume 42 Issue 10 Pages 969-974
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_969

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Smaller specimen rings were examined under the same testing condition as mentioned in the previousr eport No. 1 (Tetsu-to-Hagane Vol. 42, No. 7, p.556-561) and effects of cooling rate due to variation of specimen size have been studied primarily. Then specimens quenched from 830°C and 850°C have been scrutinized from various standpoints employing subzero treatment in order to clarify its effects, and at the same time crushing loads for these test rings were recorded.
The results were as follows:
1) Dimensional changes by aging for these specimens were smaller compared with larger rings previously tested. This decrease of dimensional changes is due to decomposing of retained austenite that takes place promptly in between quenching and tempering operations as a result of rapid cooling of smaller rings.
2) Effects of subzero treatment were as follows: At 830°C oil quenching, dimensional changes were contractive due to increase of martensite, moreover crushing values dropped and its standard deviation decreased. At 850°C oil quenching, crushing values dropped further and could not be increased very much by raising oil temperature. Very little effect was recognized even by applying marquenching and subzero treatment jointly.

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ON THE CASE-HARDENING OF STEELS BY MODIFIED GAS UTIILIZING O2 (IV)

On the Material of the Container

Naoto Shirai

1956 Volume 42 Issue 10 Pages 975-979
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_975

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The material of the container must not absorb the gas used for the special carbonitriding of steels in view of both the efficiency of the gascarbonitriding and the life of the container. In this paper the protecting power against the gas of the electro-plated steels, calo-rized steels and the various alloy cast irons were examined. It was found that the mild steel was calorized and then oxidized fully in air, and the iron alloyed with 10% Si and 1% Al or with 10% Si, 1% Al and 10% Co was the most protective against the gas.

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ON THE TRIAL MANUFACTURING OF HOT TORSION TESTING MACHINE

Kikuo Tajima, Keijiro Kugai

1956 Volume 42 Issue 10 Pages 980-985
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_980

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This report deals with the newly-designed hot torsion testing machine, and this machine cis designed to investigate the workability i.e. the strength and malleability of steels at high speed, high temperature corresponding to general hot-working processes.
This machine consists of the torque pick-up, a resistance furnace, a motor and reduction gears etc, and its capacity is as follows;
(1) Twisting speed of specimens can be changed from 30 to 1500r.p.m. by nine steps.
(2) Testing temperature range is below 1400°C.
The feature of this machine is the use of strain gage as torque measuring apparatus, and in this way, torque can be measured accurately even at initial instant of twisting.
In this article, one example of experimental resuits were described together with the construction of this machine.

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NEW RAPID METHOD FOR DETERMINATION OF GASEOUS CONTENTS IN IRON AND STEEL (II)

Determination of Hydrogen Contents in Iron and Steel

Noboru Yoneda, Hiroshi Kitagawa

1956 Volume 42 Issue 10 Pages 986-988
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_986

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Continued from p. 673; No. 8 (1956) Vol. 42 Tetsu-to-Hagane.
In this paper, the apparatus and auxiliary parts for determination of the rapid hydrogen content are described and its roles in operation are also additionally described.

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MANUFACTURING AND PROPERTIES OF TINPLATE

-A Review-

Takuo Ando

1956 Volume 42 Issue 10 Pages 989-997
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_989

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[title in Japanese]

1956 Volume 42 Issue 10 Pages 998-1004
Published: October 01, 1956
Released on J-STAGE: July 09, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.42.10_998

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