Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 43 , Issue 8
Showing 1-14 articles out of 14 articles from the selected issue
  • Nobuo Nakamura, Yutaka Sato
    1957 Volume 43 Issue 8 Pages 785-790
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    In the past decade, the authors have investigated on the low shaft furnace with an oval section which had a capacity of up to 10 tons per day. The charcoal pig iron produced by the furnace has been used as one of raw-materials for special steel. During the investigation the authors constructed some of pelletizing pilot plants and an experimental low shaft furnace with the same section as abovementioned. This furnace had a capacity of 0.6m3 corresponding to one ton per day pig iron.
    This report dealt with three times studies in regard to rapid cooling of burdens in other various experimental operations carried out with this pilot plant. The results obtained by our investigations were summarized as follows.
    (1) To correct the positions of the burdens after cooling was very important, because some effects of their shrinkages during N2 gas blowing were observed especially at upper parts of the shaft.
    (2) Segregation of the burdens was not found, while partial draft and super-heating was observed when a side tuyere had been one-sided.
    (3) Change of pellets shape began at the lower half of the bosh, and slag-formation and separation were observed.
    (4) Strength of charged pellet was weakened once at the halfway of the shaft, but the refractoriness of the pellet under load rised in proportion to increase of the degree of reduction of the pellt.
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  • Sachio Matoba, Shiro Banya
    1957 Volume 43 Issue 8 Pages 790-796
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    A study was carried out on the equilibrium of carbon and oxygen in molten iron saturated with carbon at the temperature range of 1300-1600°C, by melting Fe-C alloys in a graphite crucible within the carbon monoxide and dioxide gas atomosphere in equilibrium with graphite. As the results of this experiment, it was proved that the carbon decreased the activity coefficient of oxygen in molten iron and the products of carbon and oxygen indicated exceedingly large values in carbon saturation. For the empirical formula indicating these relation, the following results were given.
    1. Solubility of graphite:
    2. Empirical formula indicating the equilibrium relation between the carbon and the oxygen in molten iron saturated with carbon:
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  • Yoshinobu Katsufuji, Kichizo Niwa
    1957 Volume 43 Issue 8 Pages 796-801
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    The reaction rate were measured for the desulphurization of molten Fe-C-S alloys with oxygen gas by flow method.
    As the rates were proportional to the sulphur content and remained constant at a given sulphur content under the oxygen pressure between 50-500mmHg, the reaction was found to be of the first order with respect to the sulphur content. From the results that the recarburization reaction occurred during the reaction and the rate of carbon removal was proportional to square root of the oxygen pressure, it was shown that each of these two reactions took place independently in the melt.
    The rates of desulphurization were influenced by the content of carbon and that tendency corresponded with the activity of sulphur in the melt.
    The specific rate constants were much smaller than the lime slags.
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  • Yoshinobu Katsufuji
    1957 Volume 43 Issue 8 Pages 802-806
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    The reaction rates were measured for the desulphurization of molten Fe-S and Fe-S-C alloys with hydrogen gas by flow method. The following results were found.
    As the rates were proportional to the sulphur content and its logarithm linearly changed to reaction time, the reaction was found to be of the first order with respect to sulphur.
    The rates of desulphurization were influenced by the content of sulphur and carbon, and that tendency corresponded with the activity of sulphur in the melt.
    The rate constant was much larger than that of oxygen gas and smaller than that of the lime slag.
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  • Chikao Yoshii, Kazutoshi Shimanaka
    1957 Volume 43 Issue 8 Pages 807-812
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    There are a few studies of the desulphurization of molten steel by CaC2 and CaO. In the present study, 200-350gr. of a low carbon steel was melted in a magnesia crucible, deoxidized by aluminum, and then covered the surface of molten steel by powders of CaC2 or CaO as the desulphuriser. The molten steel was reacted with it for 30-40min at 1550-1600°C, and sampled every 5min for the analysis of the sulphur and oxygen.
    The results were as follows:
    Using CaO only, the sulphur decreased from 0.09% to 0.03% during 15min but then incre- ased with time. The oxygen content of this melt was 0.003% at the initial stage and began to increase in parallel with the sulphur content for lack of the deoxidising power of CaO. By addition of carbon and silicon to the steel, as the oxygen content was retained less than 0.005% throughout the whole process, the flnal sulphur content decreased to 0.01% and hardly increased.
    Using CaC2, the sulphur content was dropped from 0.1% to 0.003% within about 15min and continued to decrease little by little. The final sulphur content depended on the initial oxygen content which was contained in molten steel before the desulphurization. The final sulphur content decreased to 0.01% in molten steel of 0.008% of the initial oxygen conteht, and 0.002% in molten steel of 0.002%.
    Whenever molten steel which was contained any oxygen content was treated by CaC2, the sulphur content decreased to lower value. Because CaC2 reacted on molten steel as an effective deoxidiser and desulphuriser.
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  • Taro Hasegawa, Osamu Ochiai
    1957 Volume 43 Issue 8 Pages 812-817
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    The authors studied the lomg-time-creep-rupture properties at 600, 650 & 700°C and short-time-tensile-test properties at room and elevated temperatures of Timken 16-25-6 at the state of "hot-cold" working (hot cold worked at 700°C and 20% of reduction from as-forged, condition), as solution treated, and as precipitation hardened.
    The results were as follows:
    1. "Hot-cold" worked specimens had higher strength at the temperature below 700°C than in the other heat treated condition anq the ductility was also sufficient for practical use.
    But the effect of strain hardening decreased along with the increase of temperature and testing time, then the strength of "hot cold" worked specimens approaches to that of the other kind of heat treatment.
    2. The strength increased and reversely the ductility decreased by precipitation hardening during the elevated temperature testing. So, the precipitation-hardened specimens had lower strength and higher ductility than solution-treated specimens. This phenomenon was evident when specimens were tested at the testing temperature and time of which the rate of precipitation hardening was great. Therefore this effect was not clear in short-time-tensile-tests and long-time or high-tempesature creep rupture tests.
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  • Manabu Ueno, Hirooki Nakashima
    1957 Volume 43 Issue 8 Pages 818-821
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    The carbides of the ball bearing steels are isolated electrolytically and their nature is investigated. The results are as follows.
    (1) Electrolytic isolation of the carbide of the annealed ball-bearing steels is more effectively performed (its efficiency is about 92%). But in case of the hardened steels its efficiency falls to about 70-80%. In some material the matrix undissolves partly and contaminates the residue of the carbides.
    (2) The annealed ball-bearing steels contain the carbide about 15%. Cr, Mn, and V are contained more in the carbide and Ni in the matrix, and particularly Cr is conspicuous. In SKF steels Cr content of cementite is 9.23%, and in home-made steels 8.79%. The carbide contains 98% (SKF) and 93% (H.M) of the total Cr.
    (3) When the bearing steels are heated above A1, the chemical composition of the non-dissolved cementite changes as follows. Cr increases with the temperature, V also a little, Mn decreases first and increases somewhat afterwards.
    (4) The ball-bearing steels are usually hardened at 820-840°C, at this state the non-dissolved cementite content is 8-9% in SKF steels and 7-8% in home-made steels. The chemical compositions of the matrix are 0.5% C, 0.5-0.6% Cr and 0.2% Mn in SKF steels and 0.5% C, 0.6-0.7% Cr and 0.3% Mn in home-made steels.
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  • Michira Uchiyama, Kazunori Kamishohara
    1957 Volume 43 Issue 8 Pages 822-825
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    The Society of Automotive Engineers, U.S.A. has recommended some methods of evaluating the quality of shot-peening, most of which are utilized widely in Japan. Accordingly, the measurements of archeight or coverage are commonly practised to control or to assure the effectiveness of peening operations.
    It was made clear, however, after study of some aspects of archeight, coverage and surface roughness under various hardness combinations of shots and specimens, that the above-mentioned SAE formulae are not always stable factors for verifying the peening effect and are valid under certain conditions.
    Furthermore, the possibility of "reflecting-surface shot-peening" is confirmed, and it's practical conditions or appicable ranges are fully explained.
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  • Koi Kawamura
    1957 Volume 43 Issue 8 Pages 826-848
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
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  • Yukio Matsushita
    1957 Volume 43 Issue 8 Pages 849-854
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1957 Volume 43 Issue 8 Pages 855-858
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
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  • 1957 Volume 43 Issue 8 Pages 859-863
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    Download PDF (436K)
  • 1957 Volume 43 Issue 8 Pages 864
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    Download PDF (106K)
  • 1957 Volume 43 Issue 8 Pages 865-866
    Published: August 01, 1957
    Released: May 26, 2009
    JOURNALS FREE ACCESS
    Download PDF (114K)
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