Tetsu-to-Hagane
Online ISSN : 1883-2954
Print ISSN : 0021-1575
ISSN-L : 0021-1575
Volume 101 , Issue 4
Showing 1-5 articles out of 5 articles from the selected issue
Chemical and Physical Analysis
Regular Article
Surface Treatment and Corrosion
Regular Article
  • Makoto Nagasawa, Michio Kaneko, Kenji Katoh, Naoki Saitoh, Takeshi Tsu ...
    2015 Volume 101 Issue 4 Pages 244-251
    Published: 2015
    Released: March 31, 2015
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    It is well known that the corrosion resistance of steels is improved by the addition of alloying elements. For stainless steels, a large amount of Cr is added to obtain good corrosion resistance and the addition of rare metals such as Mo and Ni etc. are applied for further improvement of the corrosion resistance depending on corrosion environments.
    On the other hand, we investigated the effects of combining the addition of alloying elements and surface treatment aiming to develop new corrosion resistant steel at lower cost by reducing the content of alloying elements.
    We found that 6% Cr contained steel with inorganic zinc primer showed excellent anti-rust resistance in high chloride environments. Besides, the apparent rust area and maximum corrosion depth of 6% Cr contained steel were largely reduced by the addition of Al.
  • Tatsuya Koyama, Manabu Kubota, Suguru Yoshida
    2015 Volume 101 Issue 4 Pages 252-259
    Published: 2015
    Released: March 31, 2015
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    The mechanisms of decrease of carbon concentration on the surface layer after gas carburizing with increasing Si concentration was investigated using three kinds of steel whose compositions were based on JIS SCr420 varying the Si concentration (0.25%Si steel, 1%Si steel, 2%Si steel). The carbon concentration on the surface layer after gas carburizing decreased with the increase of the Si concentration, and especially that of 2%Si steel was substantially low. The carbon concentration on the surface layer after gas carburizing of 1%Si steel was nearly equal to the thermodynamic calculation value simulating the gas carburizing reaction, whereas that of 2%Si steel was much lower. This substantial change seemed to come from the oxide formation at the surface, that is, 2%Si steel was different from the other steels in oxide formation at the surface, and the oxide of 2%Si steel densely covered the surface. These results reveal that the carbon concentration on the surface layer decreased according to the effect of the inhibition of the carburizing reaction by the oxide layer in 2%Si steel in addition to the effect of the thermodynamic interaction between Si and carbon.
Transformations and Microstructures
Regular Article
  • Teruyuki Tamaki, Kenichi Murakami, Kohsaku Ushioda
    2015 Volume 101 Issue 4 Pages 260-268
    Published: 2015
    Released: March 31, 2015
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    A grain growth model based on a two-dimensional local curvature multi-vertex model in the presence of pinning particles was developed. This model is a physical model which pursues the minimum total grain boundary energy as the evaluation function, where the unpinning conditions are as follows. The first unpinning condition is that the total energy of the unpinned grain boundary is smaller than the total energy of the pinned grain boundary. The second unpinning condition is that the energy of the grain boundary necessary to surpass the energy barrier is assumed to be smaller than the jumping energy, which is presumably assisted by thermal lattice vibration. Using only the first condition, the Zener pinning effect caused by the finely dispersed particles during normal grain growth was reproduced. With the second condition, the selective abnormal grain growth was reproduced when the abnormally grown grain was surrounded by the grains with low-energy grain boundaries.
Physical Properties
Regular Article
  • Hirotoshi Tada, Hiroshi Fujimura, Hiroyoshi Yashiki
    2015 Volume 101 Issue 4 Pages 269-273
    Published: 2015
    Released: March 31, 2015
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    To reveal the influence of magnetic anisotropy on hysteresis loss of electrical steel sheet, hysteresis loss of non-oriented electrical steel sheet with various Si and Al contents and same grain diameter, 100 μm, was analyzed by the hysteresis loss model we advanced in other times. In the result, the influence of magnetic anisotropy was be able to evaluated in isolation from the influence of inner stress or texture etc. on hysteresis loss. Hysteresis loss was proportional to magnetic anisotropy constant. This reason was inferred that as the magnetic anisotropy constant decreases, the energy of magnetic wall decreases, then the magnetic wall was difficult to be pinned by precipitates or grain boundaries.
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