Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 94, Issue 5
Displaying 1-5 of 5 articles from this issue
Chemical and Physical Analysis
Regular Article
  • —Detection of Low Carbon in Steel—
    Hiroyuki Kondo, Naoya Hamada
    Article type: Regular Article
    Subject area: Chemical and Physical Analysis
    2008 Volume 94 Issue 5 Pages 155-159
    Published: May 25, 2008
    Released on J-STAGE: June 13, 2009
    JOURNAL OPEN ACCESS
    Fluorescence of atomic carbon in steel was detected at 193.09 nm by the excitation with laser pulse tuned at 247.85 nm. Solid steel samples were irradiated by pulsed Nd:YAG laser (ablation laser) to generate atomic vapor, which was then illuminated by the probe laser. One of ionic iron lines is very close to the excitation line for carbon. However, its interaction was not found to be very significant because population of ionic iron decreased faster than that of atomic carbon in a transient plasma induced by the ablation laser. When the probe laser was coaxial with the ablation laser, fluorescence spectra with high selectivity was observed with delay of 50 μs between two lasers. Fluorescence intensities were in a good linear correlation with contents of carbon in steel samples in a range of 83–5000 μg/g, which suggested that quantitative detection of carbon would be possible with the developed method.
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Forming Processing and Thermomechanical Treatment
Regular Article
  • Masahito Katoh, Yasunori Torisaka
    Article type: Regular Article
    Subject area: Forming Processing and Thermomechanical Treatment
    2008 Volume 94 Issue 5 Pages 160-163
    Published: May 25, 2008
    Released on J-STAGE: June 13, 2009
    JOURNAL OPEN ACCESS
    Micro forging using the superplasticity was tried, at austenitic stainless steal SUS304. The grains were refined by thermomechanical treatment with reverse transformation of strain induced martensite to austenite. The average grain size was about 250 nm. In the micro forging, Vickers indentation added to surface to grinded and polished flat die were used. The grain refined material, on the surface of the sample, it was possible to add a quadrangular pyramid. Bottom line of quadrangular pyramid were about 50 μm, and height was about 10 μm. On the other hand, it was not able to be carried out this process.
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  • Tadanobu Inoue, Shiro Torizuka, Eijiro Muramatsu, Kotobu Nagai
    Article type: Regular Article
    Subject area: Forming Processing and Thermomechanical Treatment
    2008 Volume 94 Issue 5 Pages 164-172
    Published: May 25, 2008
    Released on J-STAGE: June 13, 2009
    JOURNAL OPEN ACCESS
    A caliber-rolling process with new type groove characterized by multidirectional deformation was proposed to fabricate ultrafine-grained (UFG) steel bars efficiently. To impose a large strain into center of cross-section, the groove configuration of foval (flat-like-oval) type was designed. Three-dimensional finite element simulation (FE simulation) was utilized for this purpose, and the caliber-rolling process of square/foval pass was investigated from the viewpoints of a large strain accumulation and cross-sectional shape variation in a bar. The UFG steel bars were fabricated by using the commercial caliber-rolling with the grooves designed from FE simulation. The cross-sectional shape predicted from FE simulation was in excellent agreement with the shape of the rolled bars. The strain imposed in the rolled bars has a distribution with maximum at the center. The giant strain of 5.2 is accumulative in center regardless of reduction in area of 79%. The good correlation between the strain imposed and the hardness of the rolled bars was confirmed.
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Surface Treatment and Corrosion
Regular Article
  • Yoshihisa Takada, Masayoshi Suehiro, Youichi Ikematu, Kouki Tanaka
    Article type: Regular Article
    Subject area: Surface Treatment and Corrosion
    2008 Volume 94 Issue 5 Pages 173-178
    Published: May 25, 2008
    Released on J-STAGE: June 13, 2009
    JOURNAL OPEN ACCESS
    Si, Al and Mn are readily oxidizable elements, then Si, Al, Mn steels have the drawback of poor galvanizability due to the presence of complex Si–Al–Mn oxides on their surface. In order to improve the galvanizability of Si, Al, Mn steels, the effect of the addition of Ni and Cu on the wettability and galvannealing kinetics has been investigated.
    It was shown that the addition of Ni and Cu improved wettability and increased the galvannealing rate. This improvement was due to the change of the sub-micron oxide morphology just before the galvanizing treatment. In the case of C, Si, Al, Mn steel a film of Si–Al–Mn oxide was formed. The addition of Ni and Cu made Si–Al–Mn oxide intermittent and internal oxide formed remarkably.
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Transformations and Microstructures
Regular Article
  • Natsuko Sugiura, Naoki Yoshinaga, Kaoru Kawasaki, Yukiko Yamaguchi, Ju ...
    Article type: Regular Article
    Subject area: Transformations and Microstructures
    2008 Volume 94 Issue 5 Pages 179-187
    Published: May 25, 2008
    Released on J-STAGE: June 13, 2009
    JOURNAL OPEN ACCESS
    Recovery and recrystallization behavior of the Ti added low carbon steel sheets (0.0096mass%C–0.097mass%Ti) with two different states of carbon atoms were investigated. States of carbon atoms in the hot rolled sheets were characterized by 3-dimensional atom probe (3D-AP) analysis. The recovery was delayed in the sample containing solute carbon. It is considered that this delay arised from the existence of C–Mn or C–Ti dipole. After 85% cold rolling and annealing at 800°C, the specimen without solute carbon showed {111}‹112› recrystallization texture and polygonal ferrite. In contrast, the specimen contained solute carbon showed {111}‹110› recrystallization texture and pancake shaped ferrite microstructure. It is considered that the difference of recovery behavior affects development of the recrystallization texture.
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