Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 78, Issue 9
Displaying 1-12 of 12 articles from this issue
  • Masao TOYODA
    1992 Volume 78 Issue 9 Pages 1407-1413
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
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  • Eiichi SATO, Kazuhiko KURIBAYASHI, Ryo HORIUCHI
    1992 Volume 78 Issue 9 Pages 1414-1421
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
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  • Ken-ichi TAKAGI
    1992 Volume 78 Issue 9 Pages 1422-1430
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
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  • Masaki KITAGAWA, Koji YAMAGUCHI
    1992 Volume 78 Issue 9 Pages 1431-1440
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
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  • Keisuke ITO, Makoto KISHIMOTO, Katsumi MORI
    1992 Volume 78 Issue 9 Pages 1441-1448
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    The removal rates of tin and antimony in high carbon iron melt containing sulfur by evaporation have been investigated by the method of blowing argon onto the melt surface or reducing the furnace pressure. From an X-ray diffraction analysis of materials condensed, it was confirmed that tin was evaporated as SnS if sulfur coexisted but antimony was evaporated as metallic vapor. The removal rate was proportional to the 1/2 power of gas flow rate and the reciprocal of furnace pressure. An apparent activation energy for the removal process was calculated to be about 160 kJ · mol-1 from a plot of logarithm of apparent rate coefficient, R, against 1/T. This value was mainly attributed to the enthalpy change for each reaction. It was found from the results that the overall rate of removal was controlled by the diffusion rate of evaporated species in the gas phase under the present experimental conditions.
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  • Shiro BAN-YA, Fujio ISHII, Daigoro OHTAKI
    1992 Volume 78 Issue 9 Pages 1449-1455
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    The deoxidation equilibrium of hafnium in liquid iron and nickel has been measured at the temperature range from 1600°C to 1750°C using hafnia crucibles with a view to understanding the equilibrium between hafnium and oxygen in iron and nickel.
    The results obtained are summarized as follows:
    Liquid iron, log KHf(Fe) ( = aHf·a2O) = - 35840/T + 11.39
    log K'Hf(Fe) ( = [ %Hf] [ % O]2) = log KHf(Fe) + 5.85 (2[%Hf] + 11.1[%O]) (0.010.1 mass% Hf)
    Liquid nickel, log KHf(Ni) (= aHf·a2O = - 33800/T + 8.40
    log K'Hf(Ni) (= [%Hf][%O]2) = log KHf(Ni)) + 9.75(2[%Hf]+ 11.1[%O]) (0.0020.1mass% Hf)
    The activity coefficients of oxygen and hafnium in nickel-iron alloys based on pure liquid nickel are expressed by the following equation:
    logƒFeO(Ni) + 1/2 logƒFeHf(Ni) = -0.025[ %Fe]
    up to 10 mass pct of iron at temperatures between 1600°C and 1650°C.
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  • Manabu IGUCHI, Akira KAWAJIRI, Hiroshi TOMIDA, Zen-ichiro MORITA
    1992 Volume 78 Issue 9 Pages 1456-1463
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    Water and aqueous glycerol solutions were used to examine the effects of the viscosity of liquids on the bubble dispersion in a vertical bubbling jet. Bubble frequency, gas holdup, and bubble rising velocity were measured with two kinds of electro-resistivity probes. Observation of bubbles was made by means of a Schlieren method and a high speed video camera, and mean bubble diameter and bubble rising velocity were determined. With increasing the viscosity, bubbles became to flock together around the centerline of the vessel and to rise after the foregoing bubble. This phenomenon was termed "channeling of bubbles". Variations in the radial distributions of gas holdup with respect to the axial distance from the nozzle were classified into four types as functions of gas flow rate and the viscosity of liquid. The limits between the four types were determined.Correlations for gas holdup proposed so far for air-water bubbling jet were applicable to bubbling jet formed in aqueous glycerol solutions with viscosity up to about 20 mPa·s. In other words, if the bubble Reynolds number is greater than about 400 and hence the flow behind the bubble is turbulent, the correlations for gas holdup are valid.
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  • Hiroyuki TANAKA, Akira IMAMURA, Ryoji NISIHARA
    1992 Volume 78 Issue 9 Pages 1464-1471
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    Steel sheet defect caused by inclusions is a serious quality problem.
    It is said that the vertical bending type CC machine has a larger effect on removal of inclusions than the bending type CC machine.
    But the most effective vertical length for inclusion removal in a CC machine has not been studied.
    In this paper, the effective vertical length for the inclusion removal is described. This study included the investigation of steel sheet defect and the development of three dimensional numerical analysis for the study of fluid flow in the continuous caster mold. The three dimensional numerical simulation technique used in this study is the k-ε turbulence model.
    The most effective length for inclusion removal is found to be 2.53.0 m, and is found to be constant for casting conditions.
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  • Yoshiko FUNAHASHI, Sachiko TANIMOTO, Naoshi YOSHIDA, Yasuharu MATSUMUR ...
    1992 Volume 78 Issue 9 Pages 1472-1479
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    Based on the studies of electrochemical stability of precipitates in 9Cr-1Mo steels, a method for selective separation and state analysis of Laves phase was established.
    By use of this method, precipitation behavior of Laves phase and carbides was examined and the effect of Laves phase on the mechanical properties of this steel after long-time aging was studied.
    The results are summerized as follows.
    (1)Laves phase extracted from 9Cr-1Mo steel was electrochemically less stable than carbides (M23C6), and was selectively decomposed and separated from carbides by controlled-potential electrolysis at +0.8V vs. SCE in 10% acetylacetone-5%LiCl-methanol (secondary electrolysis).
    (2)The amount of Laves phase can be calculated from the total dissolved amount of Fe, Cr, Mo and Si after the secondary electrolysis. The amount of carbides (M as M23C6) can be analyzed from the total amount of Fe, Cr, and Mo in insoluble residues after the secondary electrolysis.
    (3) In the steels aged for 1000h, Laves phase was found at temperatures between 550 and 625°C, the amount was maximum at 600°C, and increased with aging.
    (4)Precipitation of Laves phase decreased the Charpy absorved energy of 9Cr-1Mo steel ; when precipitated 0.5 mass% of Laves phase, about 120J of Charpy absorved energy decreased.
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  • Koh-ichi SUGIMOTO, Noboru USUI, Mitsuyuki KOBAYASHI, Shun-ichi HASHIMO ...
    1992 Volume 78 Issue 9 Pages 1480-1487
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    The effects of silicon and manganese contents on volume fraction and stability of retained austenite in 0.2C-(1.0-2.5) Si-(1.0-2.5) Mn (mass%) TRIP-aided dual-phase steels were investigated. And, relationship between the above retained austenite parameters and ductility at room and moderate temperatures was discussed through studies on strain-induced transformation behavior of retained austenite.
    Increasing silicon and manganese contents except for 2.5mass% manganese steel, initial volume fraction of retained austenite increased with reducing carbon concentration in retained austenite. It was found that ductilities of these steels became maximum at a given temperature between 23°C and 175°C, i.e., peak temperature. The peak temperature of ductility was concluded to differ among the steels and agree well with the temperature at which strain-induced martensite transformation of retained austenite was suppressed moderately. Moreover, the peak temperature TP (°C) was related to estimated martensite-start temperature MS(°C) of the retained austenite as TP=3.04·MS+187. Strength-ductility balance at the peak temperature linearly increased with an increase in initial volume fraction of the retained austenite.
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  • Kiyotaka MATSUURA, Hirotaka SATO, Youichi ITOH, Toshio NARITA
    1992 Volume 78 Issue 9 Pages 1488-1494
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A new method has been proposed for the estimation of the distribution of the three-dimensional grain diameter in a polycrystalline material from the measured distribution of the two-dimensional grain diameter on the cross section of the material. This method has been applied to the estimation of the three-dimensional grain diameter distribution of SUS310S stainless steel during the grain growth. The three-dimensional and the two-dimensional distributions have been compared.
    The three-dimensional grain diameter distribution had the larger average value and the smaller variation coefficient, compared with the two-dimensional grain diameter distribution. The activation energy for the grain growth was larger for the analysis of the three-dimensional average grain diameters than for the two-dimensional analysis, and the value was close to those for the grain boundary diffusion of Fe, Cr and Ni.
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  • Shozaburo NAKASHIMA, Kunihide TAKASHIMA, Jirou HARASE
    1992 Volume 78 Issue 9 Pages 1495-1501
    Published: September 01, 1992
    Released on J-STAGE: May 29, 2009
    JOURNAL FREE ACCESS
    A study was made on the effect of the cooling condition in hot-band annealing on the secondary recrystallization of the grain-oriented electrical steel produced by use of MnS and AlN as inhibitors with additional Sn. The following conclusions were obtained.
    In the specimen without Sn, perfect secondary recrystallization was observed under the cases of air cooling and quenching in boiling water, and no secondary recrystallization under quenching in water. The failure of secondary recrystallization under quenching in water is attributed to the small amount of the product of {110} pole density and {111} pole density, that is, presumably, the small opportunity of meeting of Goss nuclei with easily consumable grains. In the specimen with Sn, perfect secondary recrystallization was obserbed in the all cases of cooling conditions mentioned above. The following factors are considered to be the reason why the secondary recrystallization occurs more easily in case of Sn addition ; the small size of primary grains, the large amount of the product of {110} pole density and {111} pole density in the primary texture, the large amount of MnS and AlN, and, the fine and uniform dispersion of precipitates after decarburizing annealing.
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