Hirohiko Tokunaga
Kobe Steel
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Featured researches published by Hirohiko Tokunaga.
Plasma Chemistry and Plasma Processing | 1994
Hideaki Fujimoto; Hirohiko Tokunaga; Hideki Iritani
Current users requirements for excellent product quality means that producers must discover the isothermal casting conditions which trill lead to top operating performance in the continuous casting process. In response to this requirement. a high-powered A. C. plasma arc heating system was adopted for the No. 4 Continuous Caster (No. 4CC) put into operation at Kakogawa Works. This heating system is a single-phase A.C. plasma type with two torches. This report describes research on the molten steel heating technique utilized by the A. C. plasma system, the effects of tundish atmosphere on the characteristics of plasma electric potter, and the counter- measures devised to increase the arc voltage using a suitable torch structure.
International Journal of Multiphase Flow | 1993
Manabu Iguchi; Hirohiko Tokunaga; Hideo Tatemichi; Zen-ichiro Morita
Abstract The thermal accretion (or mushroom) which is formed around the tuyere in steelmaking plants was simulated by a cold model and its formation process was observed. Single- and multi-hole nozzles were used for gas injection. The multi-hole nozzle was an artificial mushroom-like nozzle. The bubble and flow characteristics were investigated using an electrical resistivity probe and the laser Doppler velocimeter system. The process of thermal accretion formation consists of the following three stages: (1) generation of a core; (2) separation of the core and regeneration of another core; and (3) steady growth of the accretion. The shape of the thermal accretion and the bubble characteristics changed with each stage, depending on the thermal conductivity of the material of the nozzle. The bubble and liquid flow characteristics for the multi-hole nozzle were examined in comparison with those for the single-hole nozzle. The following results were obtained: (1) the bubbling jet generated by the multi-hole nozzle spread more widely in the radial direction than that generated by the single-hole nozzle; and (2) the circulation flow rate for the former nozzle was 33% larger than that for the latter nozzle.
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science | 1997
Manabu Iguchi; Hirohiko Tokunaga; Hideo Tatemichi
Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science | 1997
Manabu Iguchi; Tadatoshi Nakatani; Hirohiko Tokunaga
Archive | 1989
Yujiro Sakamoto; Toshio Kurosaka; Hirohiko Fukumoto; Toshiya Miyake; Hirohiko Tokunaga
Isij International | 1995
Hirohiko Tokunaga; Manabu Iguchi; Hideo Tatemichi
Isij International | 1994
Manabu Iguchi; Zen-ichiro Morita; Hirohiko Tokunaga; Hideo Tatemichi; Yujiro Sakamoto; Shigeo Takagi
Tetsu To Hagane-journal of The Iron and Steel Institute of Japan | 1993
Manabu Iguchi; Zen-ichiro Morita; Hirohiko Tokunaga; Hideo Tatemichi; Yujiro Sakamoto; Shigeo Takagi
Tetsu To Hagane-journal of The Iron and Steel Institute of Japan | 1992
Manabu Iguchi; Hirohiko Tokunaga; Hideo Tatemichi; Zen-ichiro Morita
Archive | 1989
Yujiro Sakamoto; Toshio Kurosaka; Hirohiko Fukumoto; Toshiya Miyake; Hirohiko Tokunaga