Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 56 , Issue 10
Showing 1-13 articles out of 13 articles from the selected issue
  • [in Japanese]
    1970 Volume 56 Issue 10 Pages 1299-1300
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Fusatoshi EMOTO, Mitsuru TATE
    1970 Volume 56 Issue 10 Pages 1301-1310
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    For the purpose of clarifying the mechanism of the reduction of iron are in the high temperature range from 900°C to 1 450°C, the rate of reduction by CO gas with and without the presence of coke was studied.
    In the case of reduction by CO gas only, the rate increased with the increase of temperature, but it became smaller when are or pellet began to fuse.
    The rate of reduction was remarkably accelerated by solid coke when are or pellet fused, however, this effect of coke was weak when it remained in the solid state.
    The rate of reduction by CO gas when temperature was raised with time was also studied and it was found that there were functional relations between heating velocity and reduction rate in the temperature rangefrom 900deg;C up to the fusion temperature. When the temperature was changed linearly with time, the degree of reduction increased linearly with temperature.
    A specially designed thermobalance with strain gauge was employed in this study.
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  • Masayuki HORIO, Iwao MUCHI
    1970 Volume 56 Issue 10 Pages 1311-1322
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    A mathematical model for analysing the dynamic characteristics of blast furnace in the region between melting zone and tuyere level are developed in this paper. On the basis of this model, the fundamental informations on the responses of both the location of melting zone and temperature of molten materials at the tuyere level to the step changes of blast temperature, steam ratio, blast volume and oil-injection rate have been obtained with the aid of digital computer.
    Three principal time constants, i. e., time constant concerning the accumulation of materials in melting zone, one related to the accumulation of heat in coke zone supposedly located below melting zone and one connected with the shifting process of melting zone, have been taken into account in the analysis. It has been found that the shifting process of melting zone affects severely on the dynamic behavior of blast furnace, since the time constant connected with this process becomes large value such as several hours.
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  • Kiichi NARITA, Takasuke MORI
    1970 Volume 56 Issue 10 Pages 1323-1341
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    Solidification processes of heavy steel ingots are analogized by using computer, and internal structure is discussed in connection with distribution of chemical elements, equi-solidus line, freezing rate (velocity of averaged advancing solidus line) and staying time (staying time between liquidus and solidus temperature). The results are as follows:
    1) An intimate relation is seen among the internal structures, freezing rate and its distribution.
    2) Inverse V segregation appeared mainly in the zone with positive acceleration of freezing rate. This means that the segregation take place in granular crystal zone as well as in equi-axial crystal zone.
    3) The pouring temperature appears to have a great influence on internal structures. In discussing the internal structures, therefore, a good care must be paid on the difference between the pouring temperature of liquid steel and the solidus temperature which is subject to the chemical composition.
    4) The internal structures along an equi-time solidus line differ in top side and bottom side. There are branched columnar crystals in the top part, equi-axial crystals in the middle part and granular crystals on the bottom parts of 20t ingot along the 2 hr-solidus line after pouring.
    5) The last solidifying zone (V segregation zone) shows the gourd-like-shape, which is obviously affected by the electric arc hot-topping, and then fine equi-axial crystals or granular crystals are formed at the bottom.
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  • Masamichi KOWAKA, Jiro SATAKE, Taishi MOROISHI, Nobukatsu FUJINO
    1970 Volume 56 Issue 10 Pages 1342-1351
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    The distribution of elements in rust layer formed on low alloy steels after various periods of exposures in industrial and rural atmospheres was investigated by means of microscopic examination and electron probe microanalysis. The rust layer in large pits contains Cu, P, and Cr in a localized state. Cr and P concentrate around such defects in the rust as voids and cracks. The local concentration of Cu seems to diminish as the exposure period becomes longer. The rust layer on the flat surface surrounding large pits and also the surface layer above large pits have shown no evidence of localized concentration of Cu and P and are characterized by the fact that little Cr content is found in the rust. Si, main constituent of dusts, has been found in these parts of the rust, but none in the pits. It is supposed that Cr, P, and Cu produced by corrosion reaction presumably form far less soluble compounds than ferrous ion and are likely to precipitate in the pits while ferrousion diffuses out from the pits and precipitates on outer surface.
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  • Shigeo WAKAMATSU
    1970 Volume 56 Issue 10 Pages 1352-1364
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    A simple and accurate method has been developed for the metallographic analysis of vanadium in high strength steel.
    1. Separation of vanadium compound from steel.
    (a) The steel sample covered with close-texture filter paper as a diaphragm and connected as an anode, is dissolved into 100 to 130ml of 1% NaCl-5% EDTA electrolyte (pH 6-7) with current density of 50 mA/cm2 for 1 to 2 hr. Remove the anode, and residue is collected into the filter paper. To the residue and filter paper add 50ml of HCl (1: 4), and pass in a stream of air for 30 min at room temperature.
    (b) Filter and wash with water. Add 5ml of HNO3 and 10ml of HClO4 to the filterate and evaporate to dense white fumes, cool, dilute to 50ml and determine vanadium as (Fe, V) 3C in accordance with section 2.
    (c) Add 30ml of HNO3 and 20ml of HClO4 to the electroyte and evaporate to dense white fumes, cool, dilute to 100ml, and determine vanadium as solid solution in accordance with section 2.
    (d) Transfer the paper and residue (paragraph (b)) to a beaker, add 30ml of HCl (1:1) and boil for 5 min.
    (e) Filter and wash with water. Add 5ml of HNO3 and 10ml of HClO4 to the filterate and evaporate to dense white fumes, cool, dilute to 50ml, and determine vanadium as V2O3 in accordance with section 2.
    (f) Transfer the paper and residue (paragraph (e)) to a beaker, add 40ml of HNO3 (1:3), and boil for 5 min.
    (g) Filter and wash with water. Add 10ml of HClO4 to the filterate and evaporate to dense white fumes, cool, dilute to 50ml, and determine vanadium as V4C3 in accordance with section 2.
    (h) Transfer the paper and residue (paragraph (g)) to a beaker, add 30ml of HNO3 (1:1) and 5ml of H2O2 and boil for 10 min.
    (i) Filter and wash with water. Add 10ml of HClO4 to the filterate and evaporate to dense white fumes, cool, dilute to 50ml, and determine vanadium as VN in accordance with section 2. Discard the residue.
    2. Photometric determination of vanadium.
    Transfer 20ml of each of solutions (section 1.(b), (c), (e), (g) and (i)) to separatory funnels, add 2ml of copper solution (0.5%) and 1 drop of KMnO4 solution (1%), and let stand for 5min. Add 15ml of N-benzoylphenylhydroyxylamine chloroform solution (0.067%) and 10ml of HCl (2:1), and shake for 30 sec. Measure the absorbance of organic phase against chloroform at 530mμ.
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  • Soji NENNO, Toshio SABURI
    1970 Volume 56 Issue 10 Pages 1365-1382
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Shigeto YAMAGUCHI
    1970 Volume 56 Issue 10 Pages 1383-1395
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Kenkichi TOSHIMA
    1970 Volume 56 Issue 10 Pages 1396-1400
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Yunoshin IMAI
    1970 Volume 56 Issue 10 Pages 1401-1405
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • Ryohei TANAKA, Takayuki SHINODA, Tomoyuki ISHII
    1970 Volume 56 Issue 10 Pages 1406-1408
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
    Hexagonal carbide V2C has never been found in steel.
    The present authors, however, found that this carbide was precipitated in 16% chromium-12% nickel-0.12% carbon austenitic steels containing vanadium by the electron microscopic and electron diffraction methods.
    The carbide V2C had lattice constants of a=2.8 Å and c=4.5 Å, and axial ratio c/a of about 1.6, and dispersed as small grain-like particles, near by carbide M23C6 which precipitated in grain boundary.
    The precipitation of the V2C carbide was found to occur only in the steels with a comparatively low value of V/-(C+ N) atomic ratio, and the carbide seemed to be a transitional phase since it disappeared after a prolonged heating.
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1970 Volume 56 Issue 10 Pages 1409-1434
    Published: September 01, 1970
    Released: October 12, 2010
    JOURNALS FREE ACCESS
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  • 1970 Volume 56 Issue 10 Pages 1435-1444
    Published: September 01, 1970
    Released: December 22, 2010
    JOURNALS FREE ACCESS
    Download PDF (2554K)
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