Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 46, Issue 14
Displaying 1-14 of 14 articles from this issue
  • [in Japanese]
    1960 Volume 46 Issue 14 Pages 1731-1732
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
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  • Study on continuous casting of steel-III
    Yoshio Aketa, Kiyoto Ushijima
    1960 Volume 46 Issue 14 Pages 1733-1740
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    In the first report of this series (ib., Tetsu-to-Hagané, 45 (1959), No. 12, p. 1341) the effect of the grimary cooling on the billet surface was studied, and it was revealed that the improper condition of corner radius, uneven cooling, too-high casting temperature and too- high casting speed induced the longitudinal surface crack of billets. In this report, the mechanism of the evolution of this longitudinal crack on the surface of a continuous cast billet was investigated.
    The mechanism of the evolution of cracks on the billet surface is essentially the same as that in the normal ingot casting. In continuous casting, however, because of the higher linear rate of casting, the tendency of the surface crack is greater than that in the normal ingot casting.
    Ferrostatic pressure of the inner molten steel causes the bending stress in the outer solid shell at the time when the shell looses contact with mold. Formula of this stress σ which consists of ferrostatic pressure ω and thickness of solid shell d is as follows:
    σ=3/16·ω·l (2x-l/3) /dd2
    On the other hand, the strength of the shell depends upon the temperature.
    Results of the experiment and the calculation reveal that the stress has a possibility of being greater than the strength. That is, the longitudinal crack may appear as soon as the billet looses contact with the mold.
    The primary cooling conditions, corner radius, evenness of cooling, casting temperature and casting speed are all related with ω, d and temperature of the billet. And, the experimental results in the first report can be explained by this mechanism of the evolution of cracks.
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  • Effect of heating rate in heat treatment-III
    Seita Sakui, Tsutomu Mori
    1960 Volume 46 Issue 14 Pages 1740-1744
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    By applying rapid heating and slow heating, 2000°C/s and 10°C/mn respectively, the effect of heating rate on some properties of a cold-rolled low-carbon steel after heat-treatment was studied.
    The results obtained were as follows:
    The temperature at which the specimen was softened completely was increased by 100°C in a rapid heating. A rapid heating resulted in the smaller grain size than that in a slow heating immediately after recrystallization. An X-ray photograph, which was taken with the recrystallized specimens, showed that a rapid heating yielded more grains with random orientations. A3 transformation was completed at 50°C in slow heating and at 30°C in rapid heating. The rapid heating refimed the grain size more effectively than the slow heating A3 transformation.
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  • Eiji Miyoshi
    1960 Volume 46 Issue 14 Pages 1744-1751
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Macroscopic non-metallic inclusions are usually inspected by naked eyes on the surface of tubes cut by the lathe. Sometimes there are many small inclusions whose length is ranged from 0·1mm to 0·4mm, but whose width is quite thin. The accuracy of this inspection was discussed here.
    At first, the accuracy caused by the individual inspector, the variance between the different inspector and the variance inspected at different times by the same inspector were tested. The results proved that the variance was large enough to cover the commercially permissible number.
    The macroscopic non-metallic inclusions are compared with the number of non-metallic inclusions counted through a microscope. The former were proved to be about 10% of the latter. This means the uncertainty of this method of inspection. This should be paid attention from the commercial point of view.
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  • Kiyoji Deguchi, Yoshimichi Matsumoto
    1960 Volume 46 Issue 14 Pages 1751-1757
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Investigations were made on the character and mechanism of the occurrence of fine (extra small) sand marks which appeared in bearing-steel SUJ 3 molten by an acid furnace.
    Further comparative tests of acid and basic furnace products were carried out.
    1) The fine sand marks appeared only in acid furnace products and the appearance of fine sand marks depended on cutting conditions. When the cutting speed was fast and the edge angle of bite small, the fine sand marks can be distinguished well.
    2) In the comparative tests, it was found that normal sand marks in basic furnace products were more numerous than in an acid furnace but A and B-type inclusions in the former were much less than in the latter and A-type inclusions were chiefly sulphide system and B-type alumina.
    3) The fine sand marks are caused by numerous A and B-type inclusions and partly by the fiber structure, and not the same as normal sand marks.
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  • Ryuichi Nakagawa, Yasuo Otoguro
    1960 Volume 46 Issue 14 Pages 1758-1764
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    In previous reports (ib. Tetsu-to-Hagané, 45 (1959), 126; 46 (1960), 377) the authors reported the effect of Nb and Ti on properties of 18Cr-12Ni austenitic stainless steels.
    This report concerned the effect of Mo and W aging behavior, microstructure, precipitates, tensile properties at various temperatures and creep-rupture strength of the same steel.
    The following results were obtained. :
    1) The steel was hardened during aging by precipitation of M6C.
    2) The precipitates of M6C, Cr23C6, Fe2Mo, Fe2W and σ phase were observed.
    The amounts of the precipitates of Fe2Mo, Fe2W and σ phase were increased as the aging temperature was elevated and as the C content was decreased and as the Mo, the W content was increased.
    3) The precipitation occurred at first on grain boundaries and secondarily within grains, and subsequently, coagulation of precipitates on grain boundaries began.
    4) Resistance to oxidation in the air at 1100°C was decreased with the Mo ahd the W contents.
    5) Tensile strength was increased linearly with the Mo or the W content at each temperature.
    The rate of increase of tensile strength was about 1kg/mmmm2 with a percent of Mo and from 1·5 to 2·0kg/mmmm2 with a percent of W.
    6) Creep rupture strength was increased with the content. The rate of increase of this strength for the steels with the higher C content was greater than that for the steels with the lower C content because of the precipitation of M6C.
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  • Study on the effect of P on properties of heat-resisting steel-II
    Naomichi Yamanaka, Kunio Kusaka, Akira Tonooka
    1960 Volume 46 Issue 14 Pages 1764-1771
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The effect of phosphorus on properties of 19-9DL type heat-resisting steels with or without addition of boron and rare earth elements was studied. The results obtained were as follows:
    (1) The phosphorus increased the maximum hardness obtained by aging after water-quenching from 1150°C, and the addition of phosphorus more than 0·2% accelerated overaging at temperatures higher than 750°C.
    (2) The phosphorus greatly improved the rupture strength at 650°C ahd 700°C, but the rupture elongation and impact value was decreased with increasing phosphorus content.
    Small addition of rare earth elements improved the ductility of the 19-9DL type heatresisting steel containing 0·15% P, and the stress-rupture values at 650°C or 700°C were equivalent to hot-cold-worked 19-9DL heat-resisting steel.
    (3) Small addition of boron improved the rupture life and ductility of the 19-9DL type heat-resisting steel containing 0·15% P with or without addition of rare earth elements.
    The new type heat-resisting steel invented by the authors contained 0·3% C, 19% Cr, 9% Ni, 1·5% W, 1·5% Mo, 0·5% Cb, 0·2% Ti, 0·15% P, 0·1% B and 0·3% rare earth elements, and the stress-rupture values at 700°C were higher than those of the LCN-155 Alloy.
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  • 1960 Volume 46 Issue 14 Pages 1771
    Published: 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
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  • Sadao Koshiba, Asao Inata
    1960 Volume 46 Issue 14 Pages 1772-1776
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The effect of V addition up to 5% on properties of high C-5Cr-W-Mo, high C-8Cr-W-Mo and high-C-12Cr-Mo steel was investigated in comparison with high C-high Cr steel (CRD).
    By the addition of V, each transformation temperature was raised and appropriate quenching temperature range was heightened. At the same time, the amount of the retained austenite was decreased and fine structure was gained.
    Such properties as dimensional change, toughness and wear resistance of these specimens were improved as the V content were raised as well as the Cr at the same V content series.
    The specimens containing a high V content in 5% Cr and 8% Cr base steels showed better wear resistance, while the toughness was generally inferior to those of CRD steel. However the specimens of a higher V content in 12% Cr-base steels were superior in toughness and wear resistance to CRD steel.
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  • Yoichi Kitamura
    1960 Volume 46 Issue 14 Pages 1777-1797
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1960 Volume 46 Issue 14 Pages 1798-1801
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
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  • [in Japanese], [in Japanese]
    1960 Volume 46 Issue 14 Pages 1802-1803
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Download PDF (731K)
  • 1960 Volume 46 Issue 14 Pages 1804-1805
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Download PDF (649K)
  • 1960 Volume 46 Issue 14 Pages 1809-1810
    Published: December 01, 1960
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Download PDF (569K)
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