Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 67, Issue 6
Displaying 1-22 of 22 articles from this issue
  • Keichi OSHIMA
    1981 Volume 67 Issue 6 Pages 649-660
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Takeshi KANAZAWA
    1981 Volume 67 Issue 6 Pages 661-671
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Kazumi MORI, Masamichi SANO
    1981 Volume 67 Issue 6 Pages 672-695
    Published: April 01, 1981
    Released on J-STAGE: January 18, 2010
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  • Hajime SUTO
    1981 Volume 67 Issue 6 Pages 696-702
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Shunsuke MORI, Yoichi KAYA
    1981 Volume 67 Issue 6 Pages 703-709
    Published: April 01, 1981
    Released on J-STAGE: January 18, 2010
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  • Yoshihiro TOMITA
    1981 Volume 67 Issue 6 Pages 710-719
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Junji KIHARA, Tatsuhiko AIZAWA
    1981 Volume 67 Issue 6 Pages 720-725
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • Tsutomu IKEDA, Katsuhiko INOUE, Toshiyuki UENAKA, Masaru KANEMOTO
    1981 Volume 67 Issue 6 Pages 726-735
    Published: April 01, 1981
    Released on J-STAGE: January 19, 2010
    JOURNAL FREE ACCESS
    The change in mineral phases during the indurating process was investigated quantitatively for industrially produced dolomite-fluxed pellets and was related to some reducing properties.
    The results obtained are summarized as follows:
    (1) The mineral phases of the pellets consist of hamatite, magnesioferrite-magnetite s. s., calcium ferrite and silicate slag. Calcium ferrite phase melts incongruently at about 1300°C, resulting in increase of liquid slag, and in consequence, the mineral phase bonding iron oxides changes from calcium ferrite to vitreous silicate slag. The contraction during reduction up to 1100°C, which was proved to be closely related to the actual performance of blast furnace, increases abruptly above this temperature. In order to minimize the contraction during reduction, it is important to keep induration temperature just below the decomposition temperature of calcium ferrite.
    (2) The chemical composition of the calcium ferrite solid solution is proposed to be CS-C(F, A)3. It should be noted that this ferrite can solve an appreciable amount of gangue components.
    X-ray precession photographs of this crystal show a c-centered monoclinic pseudo-cell with a-9.979Å, b=15.262Å, c=5.307Å, β=100.23° and a possible space group of C2/c.
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  • Fujio ISHII, Tasuku FUWA
    1981 Volume 67 Issue 6 Pages 736-745
    Published: April 01, 1981
    Released on J-STAGE: January 18, 2010
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    The equilibrium of sulphur dissolved in liquid iron with the H2-H2S mixture was studied at 1500°-1650°C in a resistance furnace or an induction furnace.
    As the discrepancy was observed among the results obtained by previous reseach groups, the effects of addition of argon to the gas mixture, of the flow rate and the preheating of the gas mixture on the apparent equilibrium constant of the following reaction were checked by applying different heating units:
    H2(g)+S=H2S(g).
    Except heating of metals, the same procedures were applied each for the preparation of the H2-H2S mixture, the flow rate of the gas mixture, and the sampling of liquid iron.
    The results obtained in this study show that a resistance furnace is preferable for the study of this system.
    The results obtained in the resistance furnace are as follows:
    logK(=PH2S/PH2·αs)=-1830/T-1.60±0.009
    ΔG°=8372+7.32T±0.04T (cal/mole).
    The activity coefficient of sulphur dissolved in liquid iron decreases with increase in its concentration, and log f's is expressed by the following equation:
    logf's=(-120/T+0.018)·[%S].
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  • Fujio ISHII, Tasuku FUWA
    1981 Volume 67 Issue 6 Pages 746-754
    Published: April 01, 1981
    Released on J-STAGE: January 18, 2010
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    The effect of alloying element on the activity coefficient of sulphur in liquid iron has been studied by equilibrating liquid iron alloy with the H2-H2S gas mixture at 1550°C in a resistance furnace.
    The results obtained show that the elements such as C, Al, Si, P, Mo and W increase the activity coefficient of sulphur, while V, Cr and Nb decrease as follows:
    log f CS=0.12[%C] C<3%
    log f A1S=0.041[%Al] Al<7%
    log f S1S=0.075[%Si] Si<7%
    log f PS=0.035[%P] P<9%
    log f VS=-0.019[%V] V<11%
    log f CrS=-0.011[%Cr] Cr<15%
    log f NiS=0.0
    log f NbS=-0.013[%Nb] Nb<12%
    log f MoS=0.0064[%Mo] Mo<20%
    log f WS=0.011[%W] W<15%.
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  • Yoichi ITO, Nobuhiro NARITA, Kaichi MATSUBARA
    1981 Volume 67 Issue 6 Pages 755-763
    Published: April 01, 1981
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    Three steels with carbon content below 0.04 % and sulfur content of 0.03 % having different manganese contents of 0.3, 0.6 and 1.2 %, respectively, were quenched from various temperatures on cooling subsequent to solidification. The number and volume fraction of manganese sulfides in those steels were measured, and also the relation between the sulfide distridution and microsegregation was examined in a 1 % Mo steel. Through these experiments, the precipitation behavior of sulfides in the steels which transformed from δ-ferrite to austenite after the completion of solidification was investigated.
    The results were as follows :
    (1) Sulfides were grouped into two categories, one crystallized by a eutectic reaction and the other precipitated after solidification. The latter was observed in all steels used in this work, but the former only in the 1.2 % Mn steel.
    (2) The crystallized sulfide, which was typical of colony type sulfides, coarsened remarkably in δ-ferrite, but hardly in austenite.
    (3) A small number of sulfides were precipitated in δ-ferrite, but after δ-γ transformation the number increased steeply.
    (4) The precipitated sulfides were classified into the colony type and non-colony type. The former increased but the latter decreased with increasing cooling rate and decreasing manganese content.
    (5) Most of the precipitated colony type sulfides were observed in the finally solidified region. The distribution of fine non-colony type sulfides was roughly uniform, while that of coarse one concentrated in the solute-enriched region, like the colony type sulfides did.
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  • Kameo MATSUKURA, Kazuaki SATO
    1981 Volume 67 Issue 6 Pages 764-773
    Published: April 01, 1981
    Released on J-STAGE: January 18, 2010
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    Planar anisotropy of γ value (Δγ=|γ090/2-γ45|) of Nb-treated high strength hot-rolled steel sheet is usually high. The way for decreasing Δγ was studied with laboratory melted materials and experimental rolling mill.
    Mechanism which leads to the increase of Δγ can probably be explained as follows: The rolling conditions such as rolling sequence or lubrication may affect the development of austenite texture in a temperature range where recrystallization does not take place. This texture is inherited by ferrite through the γ-α transformation.
    Unidirectional rolling makes Δγ higher than reverse rolling and water-lubrication or no-lubrication makes Δγ higher than oil-lubrication.
    Ti, V, Mo do not have such a strong effect of increasing the lowest temperature of γ recrystallization (Tc) as Nb does.
    So these elements are suitable to the additions for decreasing Δγ of high strength hot-rolled steel sheet for deep drawing.
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  • Toshio TAKAMATSU, Yasuo OTOGURO, Kazuhide SHIOTSUKA, Katsukuni HASHIMO ...
    1981 Volume 67 Issue 6 Pages 774-783
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    The effects of PWHT ( Postweld heat treatment ) on creep embrittlement in weldment of Cr-Mo steels for use of boiler and chemical reactor vessels were investigated.
    The correlation among rupture ductility, density and damping capacity was also investigated
    The following results were obtained.
    (1) The rupture ductility of HAZ (heat affected zone) increased with increasing PWHT temperature.
    (2) Intergranular cracking which reduced the ductility was observed under an optical microscope in the earlier period of the secondary creep stage when PWHT had been carried out at lower temperature.
    (3) The creep embrittlement of HAZ generally corresponded with decreasing density and increasing damping capacity.
    (4) The creep embrittlement of HAZ of 1Cr-1/2Mo steel was severer than that for 2 1/4Cr-1Mo steel.
    (5) The service temperature where the severest embrittlement occurred was between 500 and 550 °C for the HAZ of 1Cr-1/2Mo steel and between 550 and 600°C for that of 2 1/4Cr-1Mo steel.
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  • Haruhiko FUJITA, Manabu TANAKA, Tsune-aki SAKAKI
    1981 Volume 67 Issue 6 Pages 784-790
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    An analysis of stress and strain during creep was made on the notched bar specimens of austenitic 21-4N steel by finite element method.
    A decrease in the stress concentration at notch root due to creep deformation occurred more rapidly in the notch-strengthened ductile specimen with 36% of the grain boundary reaction (GBR) than in the notch-weakened brittle one of greater hardness (4%GBR). The equivalent strain at notch root was smaller than that of smooth specimen except in the early stage of creep in the ductile steel, but the former was always larger than the latter in the strongly notch-weakened one.
    In the brittle specimen, an increase in nominal stress enhanced the creep deformation at notch root and consequently lowered rupture time ratio of the notched specimen to the smooth one. Almost of the rupture life was spent in the creep deformation before the initiation of grain boundary cracks in the notched specimen as well as in the smooth specimen, independent of amount of GBR. Amount of plastic deformation necessary to initiate cracks was larger in the ductile specimen than in the brittle one. This is considered to greatly affect the rupture life of the notched specimen.
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  • Yasutaka OKADA, Tatsuro KUNITAKE
    1981 Volume 67 Issue 6 Pages 791-798
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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    As an ultra-high strength maraging steel which possesses the tensile strength of more than 2400 MPa, the 13Ni-15Co-10Mo steel is well known. However, it necessitates special treatments such as controlled rolling and repetition of rapid heating and cooling to improve ductility and toughness.
    Systematic investigations regarding to the effect of alloying elements on the tensile strength and toughness of ultra-high strength maraging steels are hardly known.
    For these reasons, effect of alloying elements, retained austenite and undissolved precipitates on the strength and toughness within the tensile strength range from 2000 MPa to 3000 MPa were investigated. Results are as follows.
    1) Relation between the tensile strength and toughness was strongly dependent on the combination of the amount of Ni and Mo.
    (a) Ni improved toughness remarkably.
    (b) Mo increased tensile strength strongly without drastic decrease of toughness below 8%.
    2) Ni and Mo definitely decreased Ms temperature. Decrease of tensile strength after aging due to the formation of retained austenite occured when the Ms temperature decreased below 140°C.
    3) Excess addition of Mo increased the solution treatment temperature to dissolve the precipitates, and this made the austenite grain size coarse and decreased the toughness.
    4) The 17.5Ni-6Mo steel was selected as the steel which showed the most suitable combination of strength and toughness.
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  • Osamu HASHIMOTO, Susumu SATOH, Tomo TANAKA
    1981 Volume 67 Issue 6 Pages 799-808
    Published: April 01, 1981
    Released on J-STAGE: January 18, 2010
    JOURNAL FREE ACCESS
    The effect of the volume fraction of γ phase on texture development has been investigated by making use of several extra low carbon sheet steels which were intercritically annealed in alpha plus gamma dual phase region. The results obtained are summarized in the following. (1) The texture with {111}component developed with increase in volume fraction of γ phase. The intensity of this compoment had two maxima; first at the γ fraction of less than 50% and second at the fraction of more than 60%. (2) The same behavior as (1) was obtained between the Lankford value and γ fraction. (3) The ratio of the {111} intensity of annealed sheet to that of cold rolled one was larger for a thinner specimen than for a thicker one, and also larger for surface layer than for midsection. (4) During slow cooling after intercritical annealing, {111} increased but {100} decreased in intensity. (5) In the residual α phase, {111} intensity increased with increase in γ fraction, and became maximum at 6090% γ phase transformed. (6) Those results were reasonably explained by the new theory on the formation mechanism of the α→γ→α transformation texture, which was proposed by the present authors.
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  • Ryutaro MATSUMOTO, Akihiro ONO, Tadashi IBATA, Takeshi UEMURA
    1981 Volume 67 Issue 6 Pages 809-817
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
    A new analytical system for measuring continuously concentration of trace amounts of nitrite and nitrate ions in the activated sludge aeration bath for treatment of ammonia liquor discharged from coke oven, has been developed. The developed system is based on the principle that nitrite and nitrate ions are spectrophotometrically determined at 355 nm and 302 nm, respectively, in the ultraviolet region after elimination of co-existing activated sludge and interferring materials. The proposed system are performed as follows: Sample solution taken from the aeration bath is subjected to centrifugal separation to eliminate the co-existing sludge. And then supernatant solution is passed through activated charcoal column to remove interferring colored materials. Subsequently, the solution is passed through anion exchange column for concentrating nitrite and nitrate ions. The both ions eluted separately from the anion exchange column by sodium chloride solution, are spectrophotometrically determined by ultraviolet detector. Down to 0.1 ppm and 1 ppm of nitrite and nitrate ions, respectively, can be simultaneously measured. The analytical results are automatically given once in every 10 minutes. The results agree well with those obtained by the manual method. The developed system is well applied to the ammonia liquor treatment process.
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  • Minoru SASABE
    1981 Volume 67 Issue 6 Pages 818-821
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • [in Japanese], [in Japanese], Manfred M. WOLF, [in Japanese]
    1981 Volume 67 Issue 6 Pages 822-831
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • 1981 Volume 67 Issue 6 Pages 825-825,833
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1981 Volume 67 Issue 6 Pages 836-839
    Published: April 01, 1981
    Released on J-STAGE: June 19, 2009
    JOURNAL FREE ACCESS
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  • 1981 Volume 67 Issue 6 Pages N118
    Published: 1981
    Released on J-STAGE: June 19, 2009
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