Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 49 , Issue 2
Showing 1-14 articles out of 14 articles from the selected issue
  • [in Japanese]
    1963 Volume 49 Issue 2 Pages 131-132
    Published: February 01, 1963
    Released: February 22, 2010
    JOURNALS FREE ACCESS
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  • Teinosuke YAGI, Yoichi ONO
    1963 Volume 49 Issue 2 Pages 133-138
    Published: February 01, 1963
    Released: February 22, 2010
    JOURNALS FREE ACCESS
    The knowledge of activity of the carbon in liquid iron is one of the most fundamental problems of iron-and steelmaking. But accurate values in the high-carbon range are not easily obtainable. because of experimental difficulties. So a statistical thermodynamical method was developed to estimate the activities in the whole system on the basis of available data.
    Previous works assumed the “interstitial” model for the molten Fe-C system by analogy to austenite. Comparing the previous theory with experimental values, an inconsistency of the theory was found.
    Paying special attention to the characteristics of liquid, that is, the absence of a long-range orderedness in the arrangement of atoms, the “substitutional” model was assumed which was in good agreement with experimental values in the whole system.
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  • Kazuhiro GOTO, Shiro BAN-YA, Sachio MATOBA
    1963 Volume 49 Issue 2 Pages 138-143
    Published: February 01, 1963
    Released: February 22, 2010
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    The equilibrinm of CO-CO2 gas mixture with the carbon and the oxygen in molten ironnickel and iron-chromium alloys was studied in the range of 0-100% Ni and 0-30% Cr at 1560°C, and following experimental results were obtained:
    1. The relationships between the activity coefficients of the carbon or the oxygen and dissolved elements are expressed by the following equations.
    ∂logf (Ni) C/∂%Ni=0·011……<70%Ni
    ∂logf (Cr) C/∂%Cr=-0·033……<25%Cr
    ∂logf (Ni) o/∂%Ni=0·005……<60%Ni
    2. The prodnct of the carbon and the oxygen in molten iron is decreased by addition of nickel, while it is increased by addition of chromium.
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  • Mamoru NISHIHARA, Yoshiro YAGI, Kiichi NARITA, Masao KURIHARA
    1963 Volume 49 Issue 2 Pages 144-148
    Published: February 01, 1963
    Released: February 22, 2010
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    Since consumable-electrode arc-melting is carried out at a high temperature in vacuum, some alloying elements of high vapor-pressure should evaporate in this method. In many meltings the Mn content is decreased clearly, but the contents of Cu and Sn, which show a high vapor-pressure next to Mn, is not decreased noticeably. Analyses of adhered substances on the wall of a crucible make clear that the Cu and Sn also evaporate, elements remelt into molten pool as the melting proceeds is ascertained by pulling-down and a pulling-down arcmelting shows that the evaporated elements remelt into molten pool as the melting process goes on. It should be one reason for that Cu and Sn is not decreased noticeably.
    Durations of molten state under various melting conditions calculated from the shapes of molten pools are found to be rather short. Therefore the molten metal shall be solidified before various reactions will have completed.
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  • Eiichiro ASANO, Toru ISHIDA, Hideo TAN
    1963 Volume 49 Issue 2 Pages 149-154
    Published: February 01, 1963
    Released: February 22, 2010
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    Effects of addition of Ti and B on Mn-Si, Mn-Si-Cr or Mn-Si-Mo structural steel were studied in this report III, while effects of B and Mo on Mn-Si and Mn-Si-Cr steel had been studied in the last report II (Tets-to-Hagane, 47 (1961) 4, p. 585-591).
    There were 18 grades of specimens tested. The 1st group contained 6 grades of Mn-Si steel, the 2nd group contained 7 grades of Mn-Si-Cr steel and the 3rd group contained 5 grades of Mn-Si-Mo steel.
    All samples were melted with a high-frequency induction furnace and cast into about 7kg ingots, and then forged or rolled down to 16 or 35mm_??_ bars.
    Specimens were tested under various conditions such as air-cooling or furnace-cooling after heating and quench-and-tempering.
    Tensile strength, yield strength, elongation and reduction of area were determined by tensile test. Hardness-test and microstructure-tests as well as Jominy-end-quenching test to investigate into hardenability of specimens were also made.
    The results obtained were summarized as follows:
    (1) Addition of B to Mn-Si steel containning 0·3% Ti, improved hardness, tensile strength and yield point, and decreased elongation and reduction of area only a little, under the condition of air-cooling or quench-and-tempering at a point higher than 600°C.
    (2) Effects of adding B to Mn-Si-Cr steel with 0·3% Ti on mechanical properties were not recognized apparently.
    (3) Addition of B (0·0025-0·0050%) to Mn-Si-Mo steel containning 0·13% Ti was effective on improvement of hardness and tensile strength, while decrease of elongation and reduction of area was slight. This tendency was very evident in the condilion of tempering, especially.
    (4) Ti should be treated as a deoxidizer or denitrider. From the viewpoint of mechanical properties, Ti content should be less than 0·3% in Mn-Si-Cr and Mn-Si-Mo steels.
    From the viewpoint of hardenability, Ti content should be less than 0.1% in both Mn-Si steel and Mn-Si-Mo steels.
    (5) Addition of B improved hardenability of Mn-Si, Mn-Si-Cr and Mn-Si-Mo steels.
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  • Manabu UENO, Hirooki NAKJIMA, Sadao IKEDA
    1963 Volume 49 Issue 2 Pages 155-160
    Published: February 01, 1963
    Released: February 22, 2010
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    The following studies were made for bearing steels which were melted in air (1 cast), melted in vacuum with an induction furnace (2 casts), and melted in vacuum with a consumable-electrode arc furnace (2 casts) respectively.
    Comparing the content of non-metallic inclusions in five casts of these three melting processes with each other by means of point counting, the inclusion content in vacuummelted steels was decreased to about half of that in air-melted steels, and B type inclusion was especially decreased. Moreover, gas content was decreased markedly.
    In metallographic tests, both the size and its deviation of carbide in vacuum-melted steels were a little smaller than that in air-melted steel. When the steels were austenitized, there was no remarkable difference in the amount of retained carbide. In the steels which contained vanadium, dissolution of carbide was more difficult. After quenching the amount of retained austnite and the hardness were not different between five casts.
    Life tests were carried out by using the thrust-type life test machine. Cycles to flaking are 1·65×106 in air-melted steels, 2·33×106 and 2·88×106 in two casts of vacuum induction-melted steels respectively, and 2·01×107 and 6·66×106 in two casts of consumable-electrode vacuum arc-melted steels respectively. With regerd to the standard deviations of logarithm of life cycles, vacuum induction-melted steels were inferior to air-melted steels, but vacuum arcmelted steels was superior. Therefore, it seemed that consumable-electrode vacuum arc-melted steels were superior to vacuum induction-melted and air-melted steels for the bearing uses.
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  • Taro HASEGAWA, Fukunaga TERASAKI
    1963 Volume 49 Issue 2 Pages 160-165
    Published: February 01, 1963
    Released: February 22, 2010
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    In order to improve the high-temperature strength of the heat-resistant alloy A286, it was suggested from the previous work (Zairyo Shiken, 10 (1961) No. 90, p. 70; Tetsu-to-Hagané, not yet published) that grain boundary precipitates such as G phase (Ni13Si6Ti8) and η phase (Ni3Ti) had to be eliminated by proper selections of heat treatment and/or chemical composition. From a point of view as abovementioned, the effect of heat treatment on the high-temperature strength was investigated in the present work. Solution temperatures were varied from 900°C to 1100°C and aging temperatures were selected at 650°C and 718°C. Creep rupture tests and short-time tensile tests at 650°C were carried out. X-ray diffraction was tested and an electron-microscope was used for the study of microstructures.
    The results obtained showed that the grain boundary precipitates diminished with increasing solution temperature and decreasing aging temperature, and the high-temperature strength was increased with disappearance of grain boundary precipitates. In the microstructures as heat-treated with using a solution-temperature higher than 1040°C and an aging temperature of 718°C, precipitations of TiC with various flake-type morphology were observed at grain boundaries. These precipitates, however, seemed to have little effect on the high temperature strength.
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  • Renpei YODA, Heitaro YOSHIDA, Yuuichi SATO
    1963 Volume 49 Issue 2 Pages 166-173
    Published: February 01, 1963
    Released: February 22, 2010
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    For the purpose of finding some low-cost alloys that resist to rupture at high stress at a temperature of 700-900°C, heat-resisting high-manganese steels in which part of nickel was replaced by manganese were investigated. Even if part of 10% Ni in 20% Ni content was replaced by 10% Mn, the creep rupture strength of 10% Mn alloy containing proper amount of carbon, and nitrogen was superior to that of N-155 alloy, and the high-manganese steels showed the least problems that might be posed by forging of high-alloy steels.
    The reason was based on the fact that the 10% Mn alloy containing high carbon or high nitrogen could be forged, because the deformation resistance became lower as the manganese content was increased and therefore the alloy with the excellent forgeability could be prepared therewith. The alloy containing about 4% Mn had the longest creep rupture life.
    But if the carbon content in 10% Mn alloy was increased to 0·48%, or the nitrogen content in it was increased to 0·38%, the rupture life became very longer and was equal to that of 4% Mn alloy at 700°C, and alloy that was more excellent in creep strength than N-155 alloy was obtained.
    In this case, the creep rupture life of 10% Mn alloy at 700°C became longer by addition of vanadium or phosphorus, but the effects of these elements disappeared with the alloy at above 800°C. At 700°C, the rupture life of 10% Mn alloy containing phosphorus became about four times as long as that of the alloy without phosphorus addition, but the rupture elongation became lower. The oxidation-resistance was found to be less worse as the manganese content was increased, but remarkably worse by addition of vanadium or phosphorus.
    Therefore, these alloying elements had a harmful effect on forgeability of the alloy, and there was a possibility of generation of cracking when the alloy containing phosphorus was forged. The best chemical composition of a high-manganese alloy obtained from the above facts was as follows:
    C 0·21%, Cr 19·96%, Ni 9·52%, Co 20·13%, Mn 9·91%, Mo 3·01%, W 2·79%,
    Cb 0·97%, N 0·38%, P 0·012%, Si 0·10%, O2 4·6 p. p. m.
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  • Masayoshi HASEGAWA, Ichiro ONODA
    1963 Volume 49 Issue 2 Pages 174-194
    Published: February 01, 1963
    Released: February 22, 2010
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  • 1963 Volume 49 Issue 2 Pages 195-224
    Published: February 01, 1963
    Released: February 22, 2010
    JOURNALS FREE ACCESS
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  • 1963 Volume 49 Issue 2 Pages 225-237
    Published: February 01, 1963
    Released: February 22, 2010
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
    1963 Volume 49 Issue 2 Pages 238-240
    Published: February 01, 1963
    Released: February 22, 2010
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  • 1963 Volume 49 Issue 2 Pages 243-244
    Published: February 01, 1963
    Released: February 22, 2010
    JOURNALS FREE ACCESS
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  • 1963 Volume 49 Issue 2 Pages 245-248
    Published: February 01, 1963
    Released: February 22, 2010
    JOURNALS FREE ACCESS
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