Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 54, Issue 9
Displaying 1-11 of 11 articles from this issue
  • [in Japanese]
    1968 Volume 54 Issue 9 Pages 1017-1018
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • Jun-ichiro YAGI, Keiichi SASAKI, Iwao MUCHI
    1968 Volume 54 Issue 9 Pages 1019-1031
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    In order to obtain the fundamental informations on the characteristics of blast furnace operations, the longitudinal distributions of process variables, the production rate of pig iron, and the carbon ratio were calculated numerically by the use of a mathematical model involving overall reaction rates of indirect reduction of iron are by CO and H2, carbon solution, direct reduction of molten wustite by coke, decomposition of limestone, and reaction between coke and steam.
    And these calculations were performed with the aid of digital computer under arbitrary data of operating conditions such as top gas pressure, size of charge ore, volume rate of flow of blast, blast temperature, steam ratio and enrichment of oxygen.
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  • Jun-ichiro YAGI, Keiichi SASAKI, Iwao MUCHI
    1968 Volume 54 Issue 9 Pages 1032-1037
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    On the basis of blast furnace (A), the changes of the production rate of pig iron and the carbon ratio caused by the change of the operating conditions, such as top gas pressure, average diameter of iron ores, blast volume, blast temperature, ratio of steam injection and ratio of oxygen enrichment, have been determined with the aid of the mathematical model of a blast furnace which was developed hitherto. Results obtained by use of digital computer (HITAC 5020E) are illustrated in Figs.1-9
    The production rate of pig iron increases with the increase in pressure of top gas, blast temperature, ratio of steam injection and ratio of oxygen enrichment, but the rate of the increase in production rate of pig iron for decreases with the increase in these operating factors. It is found that there is a similar tendency of the effect of the decrease in diameter of iron ores. The carbon ratio decreases with increase in top gas pressure, blast temperature and ratio of steam injection, but its variation is little in the lower region of the oxygen enrichement and increases with the oxygen enrichment in the upper region.
    For blast volume, the production rate of pig iron and the carbon ratio increase in proportion to the increase in the blast volume.
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  • Hikoya IWAI, Bunzo TSUJINO, Shigeteru ISA, Takeo Ao
    1968 Volume 54 Issue 9 Pages 1037-1046
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    The present investigation was carried out in order to obtain some fundamental information concerning the influence of non-metallic inclusions on the mechanical properties of steels.
    In most of the investigations performed by many research workers on the subject, the steel specimens were prepared by usual melting procedures. In consequence, such specimens contained many uncertain factors, affecting the mechanical properties of steels, and making it considerably difficult to investigate the influence of inclusions independently.
    In the present investigations, in order to exclude such difficulties as mentioned above as possible, steel specimens containing uniformly a certain amount of particular oxide inclusions were prepared by powder metallurgy technique.
    These steel specimens were hot-rolled under the following conditions: the rolling temperature ranges were 1250-1000°C and 1000-800°C, the rolling ratio was 1/5.
    Then, the change of inclusion in shape, composition and crystallographic structure during hot-rolling were observed. In the present experiment the behaviors of Al2O3, SiO2, TiO2, FeO·Al2O3, 2FeO·SiO2 and 2FeO·TiO2 were examined.
    The main results were as follows:
    (1) Al2O3 and SiO2 inclusions having the particle size of 105-74μ, showed fragile fracture, and the degree of fracture was increased in the case of lower rolling temperature.
    (2) Those complex oxide inclusions whose melting points were nearly the same as the rolling temperature were deformed plastically, while some others, whose melting points were higher, showed fragile fracture.They were possibly more fragile than simple oxide inclusions.
    (3) The crystalization of amorphous SiO2 was accelerated by surrounding solid iron, and most of SiO2 inclusions were transformed to α-cristobalite.
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  • Isao GOKYU, Yoshihiro SAITO
    1968 Volume 54 Issue 9 Pages 1047-1057
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    A cross-rolling technique was devised to manufacture large steel disks with high percentage yield and to improve their anisotropy of the impact value.The first half of this paper deals with a simple theory of the cross-rolling to make clear the influence of rolling conditions on the percentage yield of the disk. The last half is devoted to an experimental study of cross-rolling using plasticine as a model material to simulate the deformation of steel disks during hot cross-rolling. Finally a result oi trial manufacture of large steel disk is described.
    The results obtained are summerized as follows:
    (1) It is possible to expand the round disk keeping its shape unchanged by the orthogonal crossrolling, if the percentage reductions in the first-and second pass (cross-rolling pass) are equalized.
    (2) The percentage yield (100η) of the disk is reduced by the spread during rolling, the difference of reduction in the first-and the second pass (Δr) and angular deviation of the rolling direction of the second pass from the orthogonal direction to the first pass (oblique angle θ); and η is given by the next formula, when |Δr|<<r and |Δθ|<<1.
    where 2a and h0: diameter and thickness of a disk before rolling, R: roll radius, r= (r1+r2)/2, Δr=r1-r2 (r1 and r2 are fractinal reduction in the first-and the second pass respectively)
    (3) Concavities formed at the side surface of the disk in the early stage of repeated cross-rolling, when the thickness of the disk is relatively large, continue to grow in the suceeding rolling, causing to reduce the percentage yield of the final disk. But it is possible to increase the yield by upsettng disk before rolling to make barelling on the side surface, cross-rolling it with large reduction and reversing the direction of rolling.
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  • Tsuguyasu WADA
    1968 Volume 54 Issue 9 Pages 1058-1072
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • Toshiro KUROIWA
    1968 Volume 54 Issue 9 Pages 1073-1088
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • Chohei ASADA
    1968 Volume 54 Issue 9 Pages 1089-1092
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • Masao YUKAWA
    1968 Volume 54 Issue 9 Pages 1093-1096
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
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  • Sachio MATOBA
    1968 Volume 54 Issue 9 Pages 1097-1099
    Published: August 01, 1968
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • 1968 Volume 54 Issue 9 Pages 1100-1108
    Published: August 01, 1968
    Released on J-STAGE: December 22, 2010
    JOURNAL FREE ACCESS
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