Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 65, Issue 1
Displaying 1-17 of 17 articles from this issue
  • [in Japanese], Chikao YOSHII
    1979 Volume 65 Issue 1 Pages 1-2,157
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
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  • Tsuneyo IKI
    1979 Volume 65 Issue 1 Pages 3-23
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
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  • Yoshiaki IGUCHI, Makio IIDA, Michio INOUYE
    1979 Volume 65 Issue 1 Pages 24-33
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The pore-radius distribution of the reduced iron from hematite containing several foreign oxides was measured by the mercury penetration method. Hematite was reduced by hydrogen and carbon-monoxide at about 800° and 1000°C.
    These foreign oxides were grouped into four types depending on the effect on the pore radius.
    (1) The oxides such as Al2O3, Cr2O3 and TiO2 which are considerably soluble in hematite and magnetite but practically insoluble in wustite.
    (2) The oxides such as CaO which are considerably soluble in wustite but have limited solubilities.
    (3) The oxides such as MgO which form continuous solid solutions with wustite and do not have limited solubilities.
    (4) The oxides such as SiO2 which are almost insoluble in any iron oxides.
    According to the present work, the effects of those oxides on the pore radius in reduced iron are as follows.
    The oxides in group 1 form the micro pores of the radius which decreases with increasing the amount. The oxides in group 2 form the macro pores of the radius which increases with increasing the amount. The oxides in group 3 show practically little effect on the pore radius. The oxides in group 4 do not influence the pore radius.
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  • Yoshiaki IGUGHI, Michio INOUYE
    1979 Volume 65 Issue 1 Pages 34-43
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The pore-radius distributions in the reduced iron from magnetite and wustite containing several foreign oxides were measured by the mercury penetration method, and the cross sections of the wustite grains in the partially reduced samples were observed.
    The following results were obtained.
    (1) Wustite grains reduced from magnetite containing Al2O3 are reduced nontopochemically and the micro pores are formed in the reduced iron. However, this behavior is not observed when the wustite as a starting material contains Al2O3.
    (2) Wustite grains which are reduced from magnetite and wustite containing CaO are reduced nontopochemically and the pore radius becomes larger with increasing the quantities of CaO.
    (3) Wustite grains containing MgO are reduced topochemically as in the case of pure wustite grains and the addition of MgO gives little effect to the pore-adius of reduced iron.
    (4) It is concluded that those effects of Al2O3 and also CaO can be found when the compounds of the foreign oxides with iron oxides are precipitated in wustite during the reduction.
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  • Kiichi NARITA, Shin-ichi INABA, Isao KOBAYASHI, Ken-ichi OKIMOTO, Masa ...
    1979 Volume 65 Issue 1 Pages 44-52
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The gas temperature distribution in the throat of the blast furnace is divided into two patterns. One is named the spire type, in which the temperature is extremely high only in the central narrow part. Another is named the hill type, in which the temperature is high over the wide region of center.
    The gas temperature distribution seems to be closely related to the descending rate of burden. For the spire type, the descending rate measured by a sounding probe is higher than the average rate calculated from the charging volume of burden. For the hill type, in which the measured rate is lower than the average, the descending rate in the central part is thought to be higher than the average.
    The difference in descending rate between the central and the peripheral parts results in variation of the distribution of ore to coke ratio in stack. The variation of the layer thickness of burden in throat is theoretically calculated considering the distribution of descending rate.
    The distribution pattern of top gas temperature is closely related to the thermal condition of blast furnace, and its change usually occurs six to ten hours before the beginning of variation in the temperature of pig iron.
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  • Kazuo AMANO, Koin ITO, Hiroshi SAKAO
    1979 Volume 65 Issue 1 Pages 53-59
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Measurements have been done on the decarburization rate of the levitated Fe-13%Cr droplets with CO2-CO and CO2-Ar mixtures. The decarburization with CO2-CO mixture proceeded by keeping the value of %C×%O constant in the extent of no oxide appearance. The rate equation obtained from the analysis of the decarburization of molten iron was applied to the experimental results. It was confirmed that the reaction was determined by the mass transfer between the two phases. Also measurements have been done on the decarburization of the molten alloy in Ar atmosphare with chromic oxide, which is formed during the reaction with CO2-Ar mixture. It was estimated from the consideration that the reduction rate of the chromic oxide with carbon dissolved in the molten alloy was determined by the dissolution rate of the chromic oxide at the high concentration of carbon and by the transfer of carbon to the interface of the reaction with oxygen dissolved from the oxide at the low concentration of carbon.
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  • Kantaro SASAKI, Yasuo SUGITANI, Sumio KOBAYASHI, Susumu ISHIMURA
    1979 Volume 65 Issue 1 Pages 60-69
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The influence of the fluid flow induced by an electromagnetic stirrer and the solidification rate on the formation of the negative segregation zone in carbon steel ingots was investigated.
    The results obtained are summarized as follows.
    (1) In the region solidified in the presence of the fluid flow, the growth of columnar dendrite is suppressed and the negative segregation of all the solute elements is generated. These tendencies become remarkable when the fluid flow becomes vigorous or when the solidification rate becomes slow.
    The following relation was obtained experimentally,
    U/V≤130Ke=1-4.17x10-2 (1-k0) (U/V) 0.58U/V>≥130 Ke=0.54 (element C), 0.86 (element Mn) 0.44 (element P) where Ke is the degree of the negative segregation, U (m/sec) the flow rate of the bulk liquid, V (cm/sec) the solidification rate, and k0 the equilibrium distribution coefficient.
    (2) The washed depths in the interdendrite generated by the fluid flow were calculated for each elements by the complete mixing model. It was found that the washed depth for each element well agreed with each other and that the washed depth becomes deep when the fluid flow becomes vigorous or when the solidification rate becomes slow.
    (3) The calculated results showed that the influence of the diffusion of solute elements in the interdendrite along the solidification direction on the calculated washed depth was negligible.
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  • Akihiko HOSHINO, Keishi NAKANO, Masao KANAO
    1979 Volume 65 Issue 1 Pages 70-79
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The variation in toughness of Fe-Cr-Ni alloys having variable amount of austenite (γ) have been investigated in order to estimate the influence of γ on the susceptibility to 475°C embrittlement and σ phase embrittlement of two phase stainless steels, and the principal results are summarized as follows.
    (I) In case of heating at 700°C, the ferritic alloy was embrittled immediately by carbide precipitation. In the alloys containing more than 20%γ, there observed no embrittlement by carbide precipitation. However, marked embrittlement is observed after prolonged heating by formation of σ phase. The embrittlement by σ phase produced by decomposition of ferrite could not be reduced by coexisting γ.
    (2) On aging at 500°C of water-quenched specimens, the maximum increases in hardness and Charpy impact transition temperature appeared at 20% γ, where the maximum residual stress of ferrite was observed by means of X-ray measurement. It was supposed that this promoting action for 475°C embrittlement resulted partially from the residual stress in ferrite produced by rapid quenching of two phase alloys.
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  • Susumu HORIBE, Ryuhei SAGAWA, Toshio FUJITA, Toru ARAKI
    1979 Volume 65 Issue 1 Pages 80-89
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    The relationships between microstructures and fatigue properties in a pure iron, Fe-Ni alloys and an Fe-Ni-Cu alloy have been investigated by mechanical testing and optical or electron microscopy. Results obtained are as follows:
    (1) The degree of fatigue damage is affected by the existent states of interstitial elements and ferrite grain size in a pure iron.
    (2) Solid solution hardening by Ni or Cu restricts the softening during cycling and increases the fatigue life. The aged structures in an Fe-Ni-Cu alloy harden the alloy during cycling, which is thought to be due to the interaction between dislocations and precipitates.
    (3) Fatigue crack propagation property reflects the fatigue damage process in low ΔK level, and is affected by the grain size in a pure iron. In an Fe-Ni-Cu alloy it is improved by precipitation hardening of the Cu-rich zone.
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  • Kantaro SASAKI, Yasuo SUGITANI, Morio KAWASAKI
    1979 Volume 65 Issue 1 Pages 90-96
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Heat transfer coefficient of water spray cooling of continuous casting was investigated. A steel plate was heated in a furnace and then water spray cooling was applied with various spray nozzles. The change of the surface temperature of the steel plate was measured. The experiments were carried out in the range of the water flow rate from 0.01 to 0.25 l/cm2·min with the surface temperature of the steel plate from 700 to 1200°C. Heat transfer coefficient was calculated using the temperature measurement data of the experiment.
    The results obtained are as follows.
    (1) Heat transfer coefficient is markedly affected by water flow rate and surface temperature of a steel plate. Heat transfer coefficient can be expressed by the following equation.
    h=2.83×107W0.75·Ts-1.2+100
    where h is heat transfer coefficient (Kcal/m2·hr·°C), W is water flow rate (1/cm2·min) and Ts is surface temperature of the steel plate (°C).
    (2) The effect of water temperature on heat transfer coefficient is not remarkable, and the effect of water pressure, nozzle type and relative position between nozzle and a steel plate is negligible.
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  • Tohru IUCHI
    1979 Volume 65 Issue 1 Pages 97-106
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    A method for simultaneous measurement of both temperature and emissivity was developed by using multi-reflecting effect of radiation energy in a cavity. Each relative error of the measurement was within 1% in temperature, and 10% in emissivity respectively.
    This method brought forth a new measuring apparatus, which could not only measure the true temperature of a measuring body, but also obtain some surface informations associated with the emissivity. An on-line system of this method was developed. This system is now operated in a coated steel strip process, where it controls the furnace of the process with temperature information and the quality of the coated strips with emissivity information simultaneously.
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  • Shigekazu SUMITA, Niro KIKUCHI, Takashi MAEKAWA, Masahiro SHINMEI, Tos ...
    1979 Volume 65 Issue 1 Pages 107-112
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    X-ray fluorescence spectroscopy was applied to BF and LD slags. The following points were deduced from the results.
    1) It is estimated from Si Kα energy shifts that the basicity of the BF slag is nearly equal to that of the alkali metal orthosilicate, while that of the LD slag is somewhat larger. This is consistent with the results of the chemical analysis of these slags.
    2) The coordination number of aluminium in the slag is expected to be 4 which is reasonable considering the basic nature of the slag.
    3) Ca Kα shifts indicate that calcium is present mainly as calcium orthosilicate in the BF slag. On the other hand, in the LD slag the shift is more positive than that of the BF slag. Thus, the value implys the presence of free CaO, in accordance with chemical analysis.
    4) Chemical shifts of Mn Kβ1, 3 and Kα1 show that manganese is present as divalent ion (probably MnO).
    5) From the mathematical separation of the profile of S Kα spectra, the sulfate/sulfide ratio is evaluated. The sulfate content is about 45 and 20% in the LD and BF slags respectively.
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  • Norio FUKASAKO, Hirokazu MURASE, Kiyoshi KITA
    1979 Volume 65 Issue 1 Pages 113-119
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Anodic polarization and immersion tests in 3% NaCl solution and other chloride solutions at 35°C have been carried out using mild steels, alloy steels and aluminum alloy in order to investigate the relation between number of pits per unit area and pit diameter, shape of pit and the difference between the pit occurring by anodic polarization and that occurring by immersion.
    The results obtained are summarized as follows:
    (1) In the case of the immersion test, growth of pit is closely related to pH of the solution. Pits grow more easily in low pH solution than in high pH solution.
    (2) In the case of anodic polarization test, number of pits per unit area and their morphology depend greatly on the potential applied. The morphology of pits occurring in SUS316 by the anodic polarization test less than 0.3 VSCE is nearly same as that of naturally occured one.
    (3) It was observed that pits occured at triple points of grain boundary and at nonmetallic inclusions.
    (4) Grain boundaries, micro-pits and crystallographic morphology were observed at the bottom of pit in SUS316 after immersion in FeCl3 solution.
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  • Yoshihide ENDO, Yasuharu MATSUMURA, Takashi SUGIHARA
    1979 Volume 65 Issue 1 Pages 120-125
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
    JOURNAL FREE ACCESS
    Determination of several elements in steel by X-ray fluorescence method with chemical analysis technique was studied. Techniques used were (A) chemical separation-glass bead method, (B) precipitation separation-direct method, and (C) gasification separation-direct method. The method of item (A) was applied to the determination of niobium and tantalum, and of zirconium and hafnium. The method of (B) was applied to the determination of trace amount of tungsten and (C) was applied to arsenic determination. The method of (A) enables to determine with ease the elements, which are difficult to separate each other by conventional chemical analysis method, such as niobium and tantalum, or zirconium and hafnium. The method of (B) and (C) are suitable to trace analysis. These methods have several merits: (1) procedures are simple and rapid analysis is available, (2) obtained values agreed accurately with the certified values by chemical analysis method, (3) proper separation method is applicable, (4) it is possible to standardize with standard reagent.
    Coefficient of variation (CV) were 6%, 4%, 2% and 7% for the niobium and the tantalum of 0.04% content, the zirconium and the hafnium of 0.02% content, the arsenic of (0.001-0.005) % content, and the tungsten of 0.005% content, respectively.
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  • Yasuya OHMORI
    1979 Volume 65 Issue 1 Pages 126-137
    Published: January 01, 1979
    Released on J-STAGE: March 25, 2010
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  • Kyoji NAKANISHI, Koji SANBONGI
    1979 Volume 65 Issue 1 Pages 138-147
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
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  • Shogo TAKANASHI
    1979 Volume 65 Issue 1 Pages 148-154
    Published: January 01, 1979
    Released on J-STAGE: February 22, 2010
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