Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 57 , Issue 14
Showing 1-14 articles out of 14 articles from the selected issue
  • [in Japanese]
    1971 Volume 57 Issue 14 Pages 2169-2170
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Hiroshi NAGAYAMA
    1971 Volume 57 Issue 14 Pages 2171-2183
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    In order to investigate the source of oxide inclusions orignated from refractories of casting-pit in top-teeming ingots, Al2O3-SiO2 refractory zircon (Containing 10% and 40% as ZrO5) were used as the bottom lining of trough and ladle, trough nozzle, and the lining of mould top.
    The behaviors of oxide inclusions originated from refractories of casting-pit were studied by determining ZrO2 content in oxide inclusions extracted from steel specimens.
    The following results are obtained.
    (1) The entrapped quantity of the trough bottom brick into oxide inclusions was about 10% and the entrapped quantity into oxide inclusions was in the order of; trough bottom brick>ladle bottom brick trough mortar>trough nozzle brick>trough ramming materials>castable refractories for mould top.
    (2) Some comparisons were made between zircon tracer method and R.I. method in the investigation of the formation of oxide inclusions originated from refractories of casting-pit.
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  • Tsuneo MIYASHITA, Mitsuru OHTSUKI
    1971 Volume 57 Issue 14 Pages 2184-2196
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    An investigation was made on the oxygen enrichment to blowing gas up to 40% by using an experimental blast furnace.The oxygen ratio in this experiment was increased under the condition of constant bosh gas volume per unit time.Coke rate was slightly decreased with inc: easing the oxygen content up to 25%. In further increase of oxygen content beyond 25%, the coke rate was increased to about 2.5kg/t HNI for each 1% of oxygen enrichment, but increase of prcductivity of iron of 5% was obtained.
    Gas temperature distribution was measured to make clear the heat exchange phenomena between gases and solids, and the temperature of solids was estimated by simulation calculation. From this result, it was deduced that the oxygen enrichment blowing operation was limited due to the shortening of the length of thermal reserve zone with increase of oxygen enrichment.
    The main reason for the increase of the coke rate could be explained by calculated results of decreasing indirect reduction rate of ores which was influenced by the above temperature distribution change.
    This became another commercial limit of oxygen enrichment blowing.
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  • Rokuro SAKAGAMI, Takashi SASAI
    1971 Volume 57 Issue 14 Pages 2197-2206
    Published: December 01, 1971
    Released: December 22, 2010
    JOURNALS FREE ACCESS
    The kinetics of dissolution of SiO2 into liquid iron has been investigated by a method of rapid rise of the temperature of the melt in silica crucible from 1550° to 1600°, or 1635°.
    The oxygen increase of liquid iron is rate-controlled solely by interfacial reaction, until the equilibrium at these temperatures is reached.The following reaction in which the oxygen adsorbed at the crucible-melt interface takes part as a reactant explained well the experimental results.
    SiO2+O(ads)=Si+2O+O(ads)
    It is impossible to discuss the phenomena of the Si-deoxidation under the assumption that the local equilibrium is kept at the interface where the reaction proceeds.
    The oxygen adsorption isotherm for the interface is-estimated.
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  • Kiichi NARITA, Shinji KOYAMA, Takehisa MAKINO, Masayoshi OKAMURA
    1971 Volume 57 Issue 14 Pages 2207-2218
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    Kinetics of nitrogen desorption reaction of liquid iron and steel has been investigated by means of blowing various gas on the surface of the melt.
    The nitrogen desorption reaction of liquid iron is of second order, and the reaction rate is remarkably affected by oxygen content in liquid iron.The rate constant decreases in inverse proportion to the second power of oxygen content above 0.03%, increases gradually below this value of oxygen content and tends to approach a constant value below 0.01% of oxygen.
    From the standpoint of chemisorption of nitrogen atoms on the surface of liquid iron, these results lead to the conclusion that the rate-controlling step is the reaction between these atoms, which is disturbed by adsorbed oxygen atoms.
    The activation energy of nitrogen desorption reaction is 39 kcal/mole in liquid iron containing oxygen less than 001%.
    When the decarburization and the nitrogen desorption reactions proceed simultaneously by blowing argon and oxygen mixed gas to liquid steel, the latter reaction is deviated from the second order, and its rate becomes considerably slow in comparison with that of liquid iron by blowing only argon. These facts are considered to be caused by the disturbance of the reaction of nitrogen atoms by the oxygen atoms adsorbed on the surface of liquid steel.
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  • Kanae SUZUKI, Kazumi MORI
    1971 Volume 57 Issue 14 Pages 2219-2229
    Published: December 01, 1971
    Released: December 22, 2010
    JOURNALS FREE ACCESS
    The interdiffusivity of oxygen in molten iron was measured by the capillary method over the temperature range from 1560 to 1660°. The sample melt in a magnesia crucible reacted with Ar-H2OH2gas.
    When the initial oxygen content was below about 002%, the oxygen concentration in the lower part of the melt was increased abnormally during the process of diffusion. On the other hand, when the initial oxygen content was higher than about 002%, the abnormal behavior of oxygen was not observed.The abnormal phenomenon may be ascribed to surface diffusion of oxygen along the cruciblemelt interface. The diffusivity of oxygen which was obtained from the normal concentration profile agreed with that calculated from the total amount of oxygen diffused into the melt.
    The result is expressed by the following Arrhenius-type equation.
    D=(5.59±0.80)×10-3 exp(-19500/±750/RT) (cm2/sec)
    The present result is in good agreement with that obtained by MCCARRON and BELTON.
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  • Yasutsugu TOSHIOKA, Munemitsu FUKAGAWA, Yoshinori SAIGA
    1971 Volume 57 Issue 14 Pages 2230-2242
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    To draw benefits from fast quenching to strengthen and toughen as well as to increase the fatigue strength by taking advantage of residual stress, the stresses given rise to in steels during and after quenching were computed.
    The quenching stress, which is due to thermal strain and transformation strain, was presented as a function of changes of temperature distribution, while the method of quenching and the sizes of steel articles were conceived as the factors that determined the temperature distribution.For the steel articles state during quenching, elastic parts and plastic parts were discriminated on the basis of the maximum shear stress theory, and the transient stress distributions were obtained by integrating the stress from the quenching temperature down to an instantanius temperature.
    The computations revealed:
    1) The superficial tensile stress becomes maximum during quenching just before the transformation at the center is completed, whereas, in cases of imperfect quench, the central tensile stress becomes maximum when the steel as a whole is cooled to the room temperature.
    2) For the case of perfect quench, the superficial tensile stress is the greater the severer the quenching, though it decreases beyond a certain limit of quenching speed even becoming comperession.
    3) For imperfect quench, the stress distribution, though much depends on the quenched structure and the severity of quenching, is generally such that the superficial stress is compressive and often a sharp peak of tensile stress exists at just below the surface.
    A few practical applications have been presented and discussed.
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  • Tadashi ICHIYAMA, Ikushi YOSHIDA, Mizuo EJIMA, Osamu MATSUMURA
    1971 Volume 57 Issue 14 Pages 2243-2252
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    The effects of aluminum and nitrogen contents on recovery, recrystallization and texture-development in Fe-Al-N alloys were investigated.The specimens could be classified into two types according to their annealing behaviors.Alloys which contained less than 0.02% aluminum belonged to type I, and those which contained more than 0.060% aluminum or both aluminum (0.06%) and nitrogen were classified as type II.
    During annealing, type I alloys recovered to a greater extent than type II in which recovery was inhibited.
    In type I alloys, the recrystallization proceeded gradually after it had started.At 720°C, these alloys gave the {544}‹225›oriented recrystallization texture. This orientation became prominent as aluminum content was increased.
    On the other hand, in type II alloys, the recrystallization proceeded rapidly once it had started because of their larger driving force for grain boundary migration.At 720°C, some specimens which contained 0.06% aluminum and less than 0.005% nitrogen yielded the {111}‹110›+ {554}‹225›oriented recrystallization texture, but the others, which contained excess amount of aluminum or nitrogen, showed a wider scatter from these orientations.
    Discussions were made concerning the processes of texture development in Fe-Al-N alloys.
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  • Kiichi NARITA
    1971 Volume 57 Issue 14 Pages 2253-2272
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Hiroshi MIMURA
    1971 Volume 57 Issue 14 Pages 2273-2284
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Yoshihide ENDO, Yuki NAKAHARA
    1971 Volume 57 Issue 14 Pages 2285-2299
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Seita SAKUI
    1971 Volume 57 Issue 14 Pages 2300-2314
    Published: December 01, 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • 1971 Volume 57 Issue 14 Pages 2315-2322
    Published: December 01, 1971
    Released: December 22, 2010
    JOURNALS FREE ACCESS
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  • 1971 Volume 57 Issue 14 Pages 2326
    Published: 1971
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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