Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 59, Issue 10
Displaying 1-11 of 11 articles from this issue
  • [in Japanese]
    1973 Volume 59 Issue 10 Pages 1371-1372
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • Akira MORIYAMA
    1973 Volume 59 Issue 10 Pages 1373-1379
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    Evaporation rate of single water droplet on hot solid surface was studied.
    Theoretical rate equation was derived on the assumption that the evaporation rate of bottom part of the droplet is controlled by heat transfer through vapour film and that of upper surface of the droplet by mass transfer.
    According to this theory, the evaporation rate of upper surface of the droplet is given as a function of its volume while that of bottom part is proportional to 0.7 power of its volume. It is reasonable to neglect the inertial contribution to the flow through vapour channel between the bottom and the surface of solid at least below 800°C of the surface temperature of solid.
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  • Kazumi OGINO, Kiyoshi NOGI, Yukio KOSHIDA
    1973 Volume 59 Issue 10 Pages 1380-1387
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    By using the sessilc drop method, the wettability of solid oxide (sintered alumina and saphire) with molten iron was measured at 1600°C in atmosphere which had various oxygen potentials. The solidified metal-oxide interface was observed with optical microscope and EPMA.
    The main results are as follows;
    (1) The surface tension and contact angle of molten iron on alumina decrease with increasing of oxygen content in the metal.
    (2) The work of adhesion increascs with increase of oxygen content.
    (3) Iron diffuses into the grain-boundary of sintered alumina.
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  • Yoshikuni KAWABE, Masao KANAO, Seiichi MUNEKI
    1973 Volume 59 Issue 10 Pages 1388-1399
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    A study has been made of the effects of structural change during aging, the prior austenitic grain size and titanium addition on the tensile properties with special reference to tensile ductility of 18Ni maraging steel. The precipitation process from lath-martensitic structure to maraged structure of several stages up to overaged structure has been analyzed by using Arrhenius plots of aging hardness. The relationships between the aged structure and tensile properties have been determined.
    The results are summarized as follows:
    1) Uniform elongation increases markedly at an early stage of aging and also in overaged stage. This phenomenon is attributable to the increase of work hardening caused by the change of deformation made at former stage and γ precipitation at later stage respectively. Uniform elongation is almost independent on the prior austenite grain size.
    2) Local elongation and reduction of area decrease monotonously with increasing aging time, and show a marked decrease in overaged structure. These detrimental effects are more pronounced when the prior austenite grain size is larger and no titanium is added.
    3) The detrimental effects exhibited in overaged stage are due to the increase of void nucleation sites and increase of tendency to rupture along the prior austenite grain boundaries.
    4) The improvement of local elongation and reduction of area by titanium addition is due to the suppression of the rupture at the prior austenite grain boundaries.
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  • Hideaki SUZUKI, Tadahisa NAKAMURA
    1973 Volume 59 Issue 10 Pages 1400-1406
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    Internal friction and strain aging were studied in carburized Fe-0.5 at %Ti alloys. The carburized specimens were heated at 720°C in herium of 1atm and quenched. The Snoek damping was found to occur by the same single relaxation process as that of Fe-C alloy system, and the influence of texture, grain boundaries, cementite and magneto-mechanical damping on the relaxation strength were discussed. Strain aging was done at 15°C for 2 minutes under the unloaded and loaded condition.
    The change of the height of Snoek damping (Q-1max) and the stress increment by Snoek ordering (ΔY) with carbon content in the alloy were distinguished into three regions and discussed.
    It was found that in the region from zero to 0.12 wt% carbon and ΔY were zero, this indicating that titanium strongly binds carbon, from 0.12 to 0.15 wt% carbon Q-1max and ΔY in- creased linearly with carbon concentration, which suggests that carbon dissolves into crystal lattice, and exceeding 0.15 wt% of carbon Q-1max and ΔY decreased with carbon content, which illustrates that cementite precipitation occurs.
    It was concluded that titanium atom and carbon atom combined by the atomic ratio of 1 to 1 and that the solubility of carbon increased by 7.5 times due to the addition of 0.5 at %Ti at 720°C.
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  • Kaneyoshi KUSUNOKI, Kyozo TORII, Tatsumi ASAKURA, Noboru KOMATSU, Tohr ...
    1973 Volume 59 Issue 10 Pages 1407-1417
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    It is well known that the electrolytic boronizing is, for industrial purposes, more advantageous than other boronizing processes such as gas, pack, and salt bath processes. There is one problem in this process, however, that the boride layer tends to become less thick in a given time of processing with the repetitive use of molten borax (Na2B4O7) bath in a heat-resisting steel pot.
    In this study the cause of the deterioration of the molten salt bath were investigated and the methods to prevent it were established.
    The results obtained are summarized as follows:
    (1) The deterioration of the molten salt bath for electrolytic boronizing is considered to be due to the dissolution of iron into the bath from heat-resisting steel pot.
    (2) It is found that the deterioration can be effectively prevented by providing the passage of electric current through the bath to the pot which is to be a cathode. This method is a sort of cathodic protection.
    (3) The deterioration can be considerably reduced by the addition of ZrO2 or MgO to the bath.
    (4) The boronizing power can be restored by the removal of the iron-rich slag on the bath surface formed by the addition of a small amount of Ca, Mg, Al, Si, Zr, Ti or others into the deteriorated bath.
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  • Shozo SEKINO, Naomichi MORI, Shinogu TAMUKAI
    1973 Volume 59 Issue 10 Pages 1418-1424
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    An apparatus has been devised with which the transformation processes can be dilatometrically measured after compressive straining. With this apparatus, the deformation CCT curves can be drawn, and also the recrystallization process of austenite can be studied.
    The deformation CCT curves were drawn for a 60kg/mm2 class high tensile steel. By deformation, ferritic and bainitic transformations shifted the higher temperature and shorter time region. Ferritic transformation started along γ grain boundaries. In general, when a specimen with deformed γ grains was quenched, the micro-structure became finer and the hardness also higher.
    Recrystallization of deformed γ grains was studied by the use of an 80kg/mm2 class high tensile steel. When the degree of deformation was high, many γ grains originated along the prior γ grain boundaries and fine γ grains resulted. When the degree of deformation was low, the recrystallization was not clear, and the extraordinary grain growth occurred.
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  • Toshihiko HATA, Yoshihisa KONO, Kiyoshi SUMI
    1973 Volume 59 Issue 10 Pages 1425-1431
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
    This paper describes an analytical method for the fractionating determination of stannous sulfide and ferrous sulfide formed on the surface of some tinplates…the tinplate treated by dipping in potassium polysulfide solution and the inner face of the can of foods containing sulfide. The method is based on the difference in solubility between the sulfide and iron matrix in an dilute hydrochloric acid solution. The outline of procedure is as follows:
    To dissolve all the sulfide on the surface, sample fixed in the special dissolving vessel made of acrylic acid resin is treated with 20ml of 4N hydrochloric acid at room temperature for 20 minutes under the passing of nitrogen gas. Evolved hydrogen sulfide is absorbed in zinc acetate solution and sulfur as sulfide is determined by the methylene-blue spectrophotometric method. Then, iron in the solution is determined by the o-phenanthroline spectrophotometric method. The micro-amounts of stannous sulfide and ferrous sulfide on the surface of the sample are calculated from these analytical values.
    By this method, several samples were analysed and the satisfactory results were obtained.
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  • Kokichi ASADA
    1973 Volume 59 Issue 10 Pages 1432-1467
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • Takeo NAKA
    1973 Volume 59 Issue 10 Pages 1468-1474
    Published: September 01, 1973
    Released on J-STAGE: October 12, 2010
    JOURNAL FREE ACCESS
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  • 1973 Volume 59 Issue 10 Pages 1475-1481
    Published: September 01, 1973
    Released on J-STAGE: December 22, 2010
    JOURNAL FREE ACCESS
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