Tetsu-to-Hagane

GEN-CONVERTER PLANT AT KUKIOKA, YAWATA WORKS

Tatsuhei Uchiyama, Shigeru Maehara

1958 Volume 44 Issue 12 Pages 1347-1354
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1347

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Some experiments were carried out in 1955-56 with a 5-ton experimental oxygen converter to see whether the pure oxgen converter could be used practically in Japan. As the result it was ascertained that this method was available even to refine the high-P, high Si molten pig in Japan and the resultant products were of superior quality.
The construction of a new pure-oxygen converter plant started in Nov., 1056. It began operationon Sept. 17, the next year. The new plant, that installed two 50-ton converters, tapping 30 charges a day in average, had already produced by the end of April, 1958, 190, 000 tons of ingots for the Tobata strip mill.
The characteristics of equipments in this plant are the well-balanced layout for making the flow of operation easier and smoother, transportation of ingots and slag pans by special automobiles, the waste-gas heat boilers and dust catchers working out most completely than any other in the World, and the special pouring method by which one charge of steel is able to be poured into the ingot-cases (8 ton ingot×6) on a wagon through one fountain, etc. The mixer iron available has the average analysis of C 4.5%, Si 0.65%, Mn 0.95%, P 0.20%, S 0.03%. The product has average compositions of P 0.020%, N<sub>2</sub> 0.002% and S 0.017%. The mechanical properties of the cold-reduced strip sheets of 0.6-1.2mm thikness have shown better elongation and Erichsen values in comparison with those of the ones produced by open hearth furnaces.

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FUNDAMENTAL INVESTIGATION OF BED LININGS OF BASIC HEROULT FURNACES

Kiyoji Deguchi, Tonitaka Nishimura

1958 Volume 44 Issue 12 Pages 1354-1360
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1354

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(1) On the magesia bed linings of Héroult furnaces, the extent of molten, steel or slag penetration and their corrosion suffered were investigated fundamentally by chemical aaalysis, polararizingmicroscopic examination and x-ray diffraction. (2) In the Iinings, with which common alloy steels were melted, the detrioratlon effect is limited only to the depth. of 10 to 15mm, and fairly amount of iron oxides and limes penetrations are found in this layer. Therefore the periclase (MgO) absorbs much iron oxides, which are contained in solid solution as magnesioferrite (MgO·Fe₂O₃). Such silicates as monticellite (CaO·MgO·SiO₂), meruwinite (3CaO·MgO·2SiO2) and dicalcium silicate (β-2CaO·SiO₂) exist in the area between pericase grains. (3) In the Iinings used, for melting of high chromium alloy steels at higher temperature, more severe chaages in quality reach the depth of about 85mm, into which much. chromic oxides, iron oxides and limes penetrate. Thus chromic oxide, iron oxides and periclase react each other and picotite-chromite solid solutions (MgO·Cr₂O₃·FeO·Cr₂O₃) are precipitated, on the other hand limes form monticellite in the matrix. (4) Besides, investigations were made on slaglike material heaped on bed lining, magnesia and chromium bricks used for furnace wall. Slaglike material is molten compound of slag, magnesia and chromium bricks, and consisted of magnetite (FeO·Fe₂O₃), forsterite (2MgO·SiO₂), monticellite, diopslde (CaO·MgO·2SiO₂), periclase and spinel (MgO·Al₂O₃) etc. Magnesia bricks are not deteriorated on account of spalling, and consisted by periclase, forsterite and monticellite. Head of chromium brick changes in quality, and its mineral components are spinel, magnetite, forsterite and glass. (5) Finally, mechanisms of corrosion of magnesia lining by slag and molten steel are considered.

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STUDIES ON COMPOSITION AND PROCESS OF FORMATION OF NON-METALLIC INCLUSIONS IN STEEL INGOTS

Takeo Ao, Taneki Tokuda

1958 Volume 44 Issue 12 Pages 1360-1365
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1360

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The present report is an outcome of the results obtained during the study of the composition and process of formation of the so-called sand marks produced in steel ingots by thepresence of non-metallic substances. The results are summarized as follows:
1. Scum patches are produced by the corrosion and spalling of the runner bricks.
2. α-Alumina aggregates are produced by oxidization of the aluminum deoxidizer during formation of steel ingots by pouring. Such aggregates are never produced if aluminum is not used.
3. Non-metallic inclusions produced in bearing steel, when extracted by dissolving the steel with hot sulfuric acid, are found to consist mainly of Spinel and a little amount of α-Alumina and Quartz.

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ON THE BRICK INCLUSION TESTS BY USING A CoO TRACER

Katusige Nagami, Minoru Koya, Susumu Katube

1958 Volume 44 Issue 12 Pages 1365-1372
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1365

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The brick inclusions that presented in the 450kg ingots (killed, bottom pouring) are occurred by the erosion and fusion of the casting refractories. In this test, the authors investigated the degree of the brick inclusions occurred by the nozzle, the trumpet and the main runner bricks by use of a CoO tracer (not radio active). These three parts were considered the most important bricks concerning the brick inclusions from the. previous several investigations. The results were as follows:
(1) Assuming that scums occurred by erosion and fusion are mixed uniformly and float throughly in the mold, the floatability of these scums caused by nozzle, trumpet and main runner bricks during casting is indicated by the proportion 17:1:2 respectively. Calculated in terms of the unit length of these refractories, the floatability of scums correspond to the proportion 3.6:1.4:1 respctively.
(2) The proportion of the amount of scums which would not float is 1:110:39 respectively. These scums should be the cause of the brick inclusions.
With a view to decrease the brick inclusions in ingots, therefore, it will be advisable to improve mainly the quality of the trumpet bricks and the main runner bricks.

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LENGTH CHANGES AND TOUGHNESS ON QUENCHING, AGING AND TEMPERING

Hot-Bath Quenching of a Low W-Cr Tool Steel (SKS 2) in Low Temperature Range-II

Tatsukawa Itsuro

1958 Volume 44 Issue 12 Pages 1372-1378
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1372

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In this article, using cylindrical specimens of a 1.0% C-1.0% Cr-1.4% W tool steel, length changes on hot-bath quenching under certain conditions at temperatures both above and below its Ms point (162°C), subsequent aging at room temperature and tempering were measured. Their intensity of magnetization, hardness and toughness in statical bending test were also measured, being compared with those in the case of oil quenching and tempering.
It was found that specimens consisting of tempered martensite, lower bainite and a lot of stabilized retained austenite, obtained by hot-bath quenching below its Ms point, under such conditions of 150°C-24h or 130°C-48h, followed by aging at room temperature for several days and tempering at 180°C, showed little length change as well as possesed much greater toughness with hardness above Rc 63 than those oil-quenched and tempered ordinarily.

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ON CARBIDES IN W-Cr-V HOT-WORK DIE STEELS

Study on Carbides in Commercial Special Steels by Electrolytic Isolation-VI

Tomo-o Sato, Taiji Nishizawa, Kousuke Murai

1958 Volume 44 Issue 12 Pages 1378-1382
Published: December 01, 1958
Released on J-STAGE: January 22, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1378

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In the present study, the carbides isolated electrolytically from two kinds of W-Cr-V hot-work die steels were examined by X-ray and chemical analyses, and by electron-microscopic observations.
The carbides in the annealed steels are M₆C+M₂₃C₆(+MC), and by austenitizing treatment, M₂₃C₆, the so-called heat-treatable carbide, preferentially dissolves into the matrix, leaving a part of M₆C(+MC) as undissoloved carbides. In tempering of these steels, a transitional carbide ₂C appears, as reported by K. Kuo (J.I.S.I. vol. 174, 1953, p. 223), and the carbide phase changes in the 4th stage of tempering are as follows;
θ→W₂C(+MC)→M₆C(+MC)→M₆C+M₂₃C₆(+MC)
W concentration in the precipitated carbides increases with the rise of tempering temperature, but V and Cr concentrations in the carbides take the maximum values in the course of tempering. This fact is considered to be due to the increase of the amount of W-rich carbide M₆C, resulting in the dilution of V-rich carbide MC and Cr-rich carbide M₂₃C₆.

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STUDY ON FRACTIONAL VACUUM FUSION METHOD FOR DETERMINATION OF THE CONSTITUENT OXIDE IN STEEL

Shizuya Maekawa, Yoshitaka Nakagawa, Minoru Shudo

1958 Volume 44 Issue 12 Pages 1382-1387
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1382

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The authors studied on the applicability of factional vacuum fusion for determination of the constituent oxides in steel. The experiments were carried out on steels which had contained only two oxides for instance ferrous oxide and alumina, ferrous oxide and silica, manganous oxide and alumina, and manganous oxide and silica respectively and which had been analysed iorine method for ferrous and manganous oxides and modified Dickenson's method for silica and alumina.
A series of steels was made from an electrolytic-iron base deoxidised in different ways, with the object of producing constituent oxides of a specific type in each steel.
The results obtained were as forrows;
i) The direct total oxygen determinations by the vacuum fusion method agrees closely with the sum of the oxygen fractions by the residue methods, but does not agree with the sum of oxygen fractions by the fractional method.
ii) Each oxides content obtained by fractional vacuum fusion does not agree with that obtained by residue method, and fractional vacuum fusion method does not given a sharp separation between two oxides.
iii) It is necessary for determination of the constituent oxides in steel that the analysis take up with two or more kind of residue methods which were suitable for each oxide respectively.

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DETERMINATION OF MnO, CaO, MgO, AND P₂O₅

Study on the Chemical Analysis of Sand Iron and IImenite-III

Shigeo Wakamatsu

1958 Volume 44 Issue 12 Pages 1387-1392
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1387

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In the report (I) and (II), the methods for the determination of total Fe, FeO, TiO₂, SiO₂, Al₂O₃, V₂O₅, and Cr₂O₃ in sand iron and ilmenite were developed. In this report, a simple photometric or volumetric methods is described for the determination of MnO, CaO, MgO, and P₃O₅ which are contained in sand iron and ilmenite. MnO is determinedby photometric or volumetric methods with the (NH₄)₂S₂O₈. CaO and MgO are determined by the EDTA titration method. P₂O₅ is determined by photometric method using the molybdenum blue.

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ON THE METHOD FOR REVEALING THE AUSTENITIC GRAIN SIZE IN STEEL

Yunoshin Imai, Hiroshi Hirotani

1958 Volume 44 Issue 12 Pages 1393-1407
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1393

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[title in Japanese]

F Wever

1958 Volume 44 Issue 12 Pages 1408-1417
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1408

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[title in Japanese]

1958 Volume 44 Issue 12 Pages 1418-1423
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1418

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[title in Japanese]

[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...

1958 Volume 44 Issue 12 Pages 1424-1429
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1424

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[title in Japanese]

1958 Volume 44 Issue 12 Pages 1430
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1430

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[title in Japanese]

1958 Volume 44 Issue 12 Pages 1431-1434
Published: December 01, 1958
Released on J-STAGE: May 26, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.44.12_1431

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