Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 44, Issue 4
Displaying 1-13 of 13 articles from this issue
  • Effeet of Si, P on Mn-S equilibrium in C-Saturated molten iron-Part 1
    Kokichi Sano, Michio Inouye
    1958 Volume 44 Issue 4 Pages 461-466
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    In a previous paper it was shown that the high sulphur potential in carbon-saturated liquid iron resulted in the effective desulphurization by manganese. (Tetsu-to-Hagané vol. 43, 1957 pp. 517 & 535)
    In this second report, the effect of silicon and phosphorus addition to carbon-saturated iron melts on the Mn-S equilibrium was investigated.
    The results showed that the silicon addition improved desulphurization by manganese in higher silicon range, but on the contrary the phosphorus addition had somewhat reverse effect.
    However, since such effects were negligible in their lower contents such as below 2%, it should be especially emphasized that the desulphurization limit of normal blast-furnace pig iron was wholly dependent upon the carbon saturation.
    The effect of silicon or phosphorus addition presumably was ascribed to increase or decrease of activity coefficient of the sulphur in those melts, which was estimated referring to the previous data of the experiment on Fe-Csat-Mn-S system.
    The results approximately agreed with those calculated by Wagner's, equation in their lower contents.
    Finally, the effect of dissolved sulphur on the solubility of carbon in Fe-C-Si and Fe-C-P melts were discussed.
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  • Sampling method of molten steel near the solidus in the large ingot during solidification process
    Shizuya Maekawa, Yoshitaka Nakagawa
    1958 Volume 44 Issue 4 Pages 467-470
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    The defects that appear in an ingot such as flakes, ghóst streaks and sand marks are produced the moment the steel solidifies from liquid into solid by the difference of physical and chemical properties between molten and solid steel. But even if physical and chemical properties both in liquid and solid steel were known completely, yet it would be very difficult to grasp the actual situations of what were going on during each of the various processes which manifold kinds of molten steel must go through in actual casting operation until they became solidified.
    Then the author wished to investigate the variation of chemical element and gases content of molten steel near the solidus in the large ingot during solidification process. For the purpose of this investigation the author established a method of sampling of molten steel near the solidus.
    A sampler as shown in Fig. 2 and Photo. 4 was immersed into molten steel in a mold and let it approach nearly to solidus, then was kept for a certain period of time in that position.
    The copper plate would soon melt away to fill the molten steel into the guartz tube which was then withdrawn.
    The author collected the molten steel from the position without failure by dipping the sampler in the molten steel for between 35 and 75 seconds under the conditions of the temperature at 1480-1510°C at the sinkhead part of an ingot of 9-20 tons below surface of the molten steel 1-2.5m.
    The molten steel in the tube was water-cooled and used for analytical samples of chemical components including hydrogen, oxygen, nitrogen and various oxides.
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  • On the formation of pearlite-free structure
    Kiyoshi Yoshida
    1958 Volume 44 Issue 4 Pages 471-475
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    The microstructure of low-carbon rimmed steel specimens cooled continuously from their austenite range to the room temperature at the various cooling rates was investigated in relation to their cooling rates. All specimens were first given a homogenizing annealing at 950°C for 30mn. They were then rapidly coold at the rates of 300°C/mn, 150°C/mn, or 20°C/mn to the different temperatures, 800°C, 750°C, 700°C and 650°C and subsequently cooled slowly to the room temperature at the rate within the range from 3°C/mn to 96°C/mn.
    The results obtained were as follows.
    1) Cooling slowly at the rate 3°C/mn below 700°C a pearlite-free structure was formed with the 0.08% C specimens cooled at the rate above 150°C/mn to 700°C and with the 0.05% C specimens cooled at the rate above 20°C/mn to the same temperature. In other words, the formation of the pearlite-free structure was affected by the temperature at which the slow cooling began and also by the slow cooling rate.
    2) The specimens which showed the pearlite-free structure gave the exceedingly high Charpy impact values in comparison with the annealed specimens of the same chemical composition.
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  • Ca uses of formation of duplex-grain structures in steels (Part-1)
    Yoshiaki Masuko
    1958 Volume 44 Issue 4 Pages 476-479
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    By the systematic experiments and some theoretical considerations from the view point of grain-growth characteristics of austenite, causes of formation of duplex-grain structures in steels were made clear, and some suggestions were given in relation to the prevention of such structures.
    Results of these investigations are summarized as follows:
    (1) "Uniform duplex-grains" appear in the stage of abrupt coarsening of austenite resulting from the dissolution of grain-growth inhibitors into it.
    (2) "Non-uniform duplex-grains" are due to the primary segregation of grain-growth inhibitors leading to the non-uniform distribution of initial austenite grains on heating through the critical point.
    (3) Grain-growth inhibitors are predominantly AIN in Al-treated steels, and the relation between the amount of AlN and its degree of segregation determines whether these steels have "uniform duplex-grains" or "non-uniform duplex-grains".
    (4) For the prevention of "duplex-grains", it is necessary to reduce the primary segregation as little as possible and to preserve the suitable amount of AlN in steels.
    (5) In addition, it is indicated that "uniform duplex-grains" appear also in the stage of grain-growth after recrystallization of hot-worked steels and "non-uniform duplex-grains" appear also in hyper-eutectoid steels resulting from the primary segregation of carbides.
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  • Yunoshin Imai, Hiroshi Hirotani
    1958 Volume 44 Issue 4 Pages 480-482
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    A new oxidizing method for revealing austenitic grains is examined by using borax. When the specimen is exposed to air at high temperatures for a few seconds, the austenitic grain boundary is usually more oxidized than the matrix, and when such oxidized specimen is dipped into molten borax, the thin film of oxide melts away into borax, and the grain boundary appears clearly as a thin groove.
    According to the results with some carbon steels and special steels, the present method seems to be superior to others in practical use on account of its simple and reliable technique.
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  • Manabu Ueno, Hirooki Nakashima
    1958 Volume 44 Issue 4 Pages 483-486
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    In isolation of carbides of bearing steels their matrices do not always completely dissolve electrolytically. There is the so-called "peeling phenomenon" of the matrix in some samples.
    In this report, effect of the electrolytic potential and the copper content in steels on this phenomenon is discussed.
    (1) In electrolytic isolation of carbides of bearing steels the peeled matrix increases its amount, when the steel is quenched from higher temperature. This phenomenon is due to the reason why retained austenite increases at the higher quenching temperature and electrolytic potential of the matrix becomes nobler.
    (2) The less copper content in steels, the baser the electrolytic potential of the steels without current and the less the amount of the peeled matrix. Electrolytic potential of bearing steel specimen is baser in the annealed than in the quenched state.
    (3) The amount of the peeled matrix has a distinct relation to the copper content of the steels: its coefficient of correlation is 0.86. It is presumed that even a slight copper content in steels has at least a great influence on electrochemical properties of the steels.
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  • Sadao Koshiba, Kingo Kiyonaga
    1958 Volume 44 Issue 4 Pages 487-492
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    Hardenabilities of 17 self-hardening steels were investigated with reference to the relation of hardness vs. "half-temperature time". Mass effects of these steels were deduced from the grossmann's diagram, and the results showed good coincidence with experimental values. Due to the above investigation, it became obvious that there was a considerable difference ameng hardenabilities of various self-hardening steels.
    Further, the authors referred to the secondary hardening characteristics of these steels due to tempering after slack quenching at various cooling rates. As the results, bainite seemed to be stable for temper-softening and qualifiedfor the transformation and precipitation which led to a secondary hardening.
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  • [in Japanese], [in Japanese]
    1958 Volume 44 Issue 4 Pages 493-504
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
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  • Tasaburo Yamada
    1958 Volume 44 Issue 4 Pages 505-514
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
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  • 1958 Volume 44 Issue 4 Pages 515
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
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  • 1958 Volume 44 Issue 4 Pages 516-523
    Published: April 01, 1958
    Released on J-STAGE: January 22, 2010
    JOURNAL FREE ACCESS
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  • 1958 Volume 44 Issue 4 Pages 524
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    Download PDF (97K)
  • 1958 Volume 44 Issue 4 Pages 525-527
    Published: April 01, 1958
    Released on J-STAGE: May 26, 2009
    JOURNAL FREE ACCESS
    Download PDF (167K)
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