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Watanabe, Miku*; Miyamoto, Goro*; Zhang, Y.*; Morooka, Satoshi; Harjo, S.; Kobayashi, Yasuhiro*; Furuhara, Tadashi*
ISIJ International, 64(9), p.1464 - 1476, 2024/07
Kadoi, Kota*; Kanno, Yudai*; Aoki, So; Inoue, Hiroshige*
ISIJ International, 64(9), p.1450 - 1456, 2024/07
The influence of the chemical composition on the pitting corrosion in the weld metal of austenitic stainless steel were investigated. The specimens containing higher content of chromium and molybdenum showed the lower the reactivation rate. The addition of titanium drastically deteriorated the pitting corrosion resistance. The chromium depleted region was formed near the carbide such as MC and TiC. Besides, TiC phase which formed during solidification acted as nucleation sites for MC precipitation. The depleted region caused by chromium diffusion because of the MC precipitation, induced to deteriorate the pitting corrosion resistance.
Ueji, Rintaro*; Gong, W.; Harjo, S.; Kawasaki, Takuro; Shibata, Akinobu*; Kimura, Yuji*; Inoue, Tadanobu*; Tsuchida, Noriyuki*
ISIJ International, 64(2), p.459 - 465, 2024/01
Times Cited Count:0 Percentile:0.00(Metallurgy & Metallurgical Engineering)Yamashita, Takayuki*; Harjo, S.; Kawasaki, Takuro; Morooka, Satoshi; Gong, W.; Fujii, Hidetoshi*; Tomota, Yo*
ISIJ International, 64(2), p.192 - 201, 2024/01
Times Cited Count:0 Percentile:0.00(Metallurgy & Metallurgical Engineering)Zhang, Y.*; Marusawa, Kenji*; Kudo, Kohei*; Morooka, Satoshi; Harjo, S.; Miyamoto, Goro*; Furuhara, Tadashi*
ISIJ International, 64(2), p.245 - 256, 2024/01
Times Cited Count:2 Percentile:71.29(Metallurgy & Metallurgical Engineering)Harjo, S.; Gong, W.; Kawasaki, Takuro; Morooka, Satoshi; Yamashita, Takayuki*
ISIJ International, 62(10), p.1990 - 1999, 2022/10
Times Cited Count:1 Percentile:10.52(Metallurgy & Metallurgical Engineering)Koyama, Motomichi*; Yamashita, Takayuki*; Morooka, Satoshi; Sawaguchi, Takahiro*; Yang, Z.*; Hojo, Tomohiko*; Kawasaki, Takuro; Harjo, S.
ISIJ International, 62(10), p.2036 - 2042, 2022/10
Times Cited Count:15 Percentile:84.05(Metallurgy & Metallurgical Engineering)Koyama, Motomichi*; Yamashita, Takayuki*; Morooka, Satoshi; Yang, Z.*; Varanasi, R. S.*; Hojo, Tomohiko*; Kawasaki, Takuro; Harjo, S.
ISIJ International, 62(10), p.2043 - 2053, 2022/10
Times Cited Count:9 Percentile:66.16(Metallurgy & Metallurgical Engineering)Iwamoto, Chihiro*; Takamura, Masato*; Ueno, Kota*; Kataoka, Minami*; Kurihara, Ryo*; Xu, P. G.; Otake, Yoshie*
ISIJ International, 62(5), p.1013 - 1022, 2022/05
Times Cited Count:2 Percentile:21.00(Metallurgy & Metallurgical Engineering)Amemiya, Yutaro*; Nakada, Nobuo*; Morooka, Satoshi; Kosaka, Makoto*; Kato, Masaharu*
ISIJ International, 62(2), p.282 - 290, 2022/02
Times Cited Count:3 Percentile:31.34(Metallurgy & Metallurgical Engineering)Oba, Yojiro; Morooka, Satoshi; Oishi, Kazuki*; Suzuki, Junichi*; Tsuchiyama, Toshihiro*
ISIJ International, 62(1), p.173 - 178, 2022/01
Times Cited Count:3 Percentile:31.34(Metallurgy & Metallurgical Engineering)Nakayama, Yuta*; Ogawa, Fumio*; Hiyoshi, Noritake*; Hashidate, Ryuta; Wakai, Takashi; Ito, Takamoto*
ISIJ International, 61(8), p.2299 - 2304, 2021/08
Times Cited Count:5 Percentile:32.89(Metallurgy & Metallurgical Engineering)This study discusses the creep-fatigue strength for Mod.9Cr-1Mo steel at a high temperature under multiaxial loading. A low-cycle fatigue tests in various strain waveforms were performed with a hollow cylindrical specimen. The low cycle fatigue test was conducted under a proportional loading with a fixed axial strain and a non-proportional loading with a 90-degree phase difference between axial and shear strains. The low cycle fatigue tests at different strain rates and the creep-fatigue tests at different holding times were also conducted to discuss the effects of stress relaxation and strain holding on the failure life. In this study, two types of multiaxial creep-fatigue life evaluation methods were proposed: the first method is to calculate the strain range using Manson's universal slope method with considering a non-proportional loading factor and creep damage; the second method is to calculate the fatigue damage by considering the non-proportional loading factor using the linear damage law and to calculate the creep damage from the improved ductility exhaustion law. The accuracy of the evaluation methods is much better than that of the methods used in the evaluation of actual machines such as time fraction rule.
Adachi, Nozomu*; Ueno, Haruki*; Onoe, Katsuhiko*; Morooka, Satoshi; Todaka, Yoshikazu*
ISIJ International, 61(8), p.2320 - 2322, 2021/08
Times Cited Count:4 Percentile:26.64(Metallurgy & Metallurgical Engineering)Igarashi, Takahiro; Otani, Kyohei; Kato, Chiaki; Sakairi, Masatoshi*; Togashi, Yusuke*; Baba, Kazuhiko*; Takagi, Shusaku*
ISIJ International, 61(4), p.1085 - 1090, 2021/04
Times Cited Count:2 Percentile:12.81(Metallurgy & Metallurgical Engineering)In order to clarify the effect of metal cations (Zn, Mg, Na) in aqueous solution on hydrogen permeation into iron, the amount of hydrogen permeation from iron surface was measured by electrochemical tests with a laser ablation. Moreover, in order to obtain the basic mechanism of hydrogen permeation with metal cation, first-principles calculations were used to acquire the adsorption potential of the metal cation and the electronic state around iron surface. By Zn in solution, anodic reaction on ablated surface by laser irradiation was suppressed. Also, by quantum analysis Zn atoms were chemically bonded stronger than Na and Mg atoms to iron surface. It was suggested that the dissolution reaction of iron was suppressed by the formation of the Zn layer, and that lead suppression of hydrogen permeation into iron.
Shibayama, Yuki; Hojo, Tomohiko*; Koyama, Motomichi*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Matsuno, Takashi*; Akiyama, Eiji*
ISIJ International, 61(4), p.1322 - 1329, 2021/04
Times Cited Count:7 Percentile:38.77(Metallurgy & Metallurgical Engineering)Nishimura, Hayato*; Hojo, Tomohiko*; Ajita, Saya*; Shibayama, Yuki*; Koyama, Motomichi*; Saito, Hiroyuki*; Shiro, Ayumi*; Yasuda, Ryo*; Shobu, Takahisa; Akiyama, Eiji*
ISIJ International, 61(4), p.1170 - 1178, 2021/04
Times Cited Count:6 Percentile:32.89(Metallurgy & Metallurgical Engineering)Harjo, S.; Kawasaki, Takuro; Tsuchida, Noriyuki*; Morooka, Satoshi; Gong, W.*
ISIJ International, 61(2), p.648 - 656, 2021/02
Times Cited Count:7 Percentile:44.23(Metallurgy & Metallurgical Engineering)Hosoya, Yoshihiro*; Matsumura, Yuta*; Tomota, Yo*; Onuki, Yusuke*; Harjo, S.
ISIJ International, 60(9), p.2097 - 2106, 2020/09
Times Cited Count:6 Percentile:26.89(Metallurgy & Metallurgical Engineering)Islam, M. S.*; Otani, Kyohei; Sakairi, Masatoshi*
ISIJ International, 58(9), p.1616 - 1622, 2018/09
Times Cited Count:7 Percentile:34.08(Metallurgy & Metallurgical Engineering)To elucidate the role of Zn on corrosion of coated steel, the effects of metal cations on the corrosion of carbon steel in the concentrated Cl aqueous solutions were studied by immersion tests, surface analysis and electrochemical tests. Among the examined metal cations, Zn showed the significant effect on corrosion inhibition of carbon steel in the Cl aqueous solution at high concentration. XPS analysis results elucidated that Zn can remain on the steel surface after immersed in the solutions with Zn. EIS measurements showed higher impedance in the solution with Zn than other solutions, and the results suggested that Zn reduced the defect points in the thin oxide film by forming a metal cation layer. Based on the experimental results, Zn may form a layer on the oxide film that protects the Cl attack in the solution. The findings demonstrated that the formation of Zn layer on the oxide film is one of the main reason for showing high and longtime corrosion resistance of Zn coated steel substrate.
Sato, Shigeo*; Shobu, Takahisa; Sato, Kozue*; Ogawa, Hiromi*; Wagatsuma, Kazuaki*; Kumagai, Masayoshi*; Imafuku, Muneyuki*; Tashiro, Hitoshi*; Suzuki, Shigeru*
ISIJ International, 55(7), p.1432 - 1438, 2015/07
Times Cited Count:13 Percentile:52.07(Metallurgy & Metallurgical Engineering)To characterize the distribution and anisotropy of dislocations in cold-drawn pearlitic steel wires, X-ray diffraction line-profile analysis was performed using synchrotron radiation micro-beams. The plastic shear strain was generally more severe near the surface than the center of the wire, whereas the dislocation density distribution was almost constant from the center to the surface. On the other hand, the dislocation rearrangement, which evolves the dislocation cell structure, progressed closer to the surface. It was also revealed that a difference between the hardness in axial and transverse wire directions could be explained by anisotropic dislocation density. Line-profile analysis based on diffraction data at elevated temperatures was performed. Whereas the cementite recovery progressed at a constant rate, the ferrite phase recovery rate was temperature-dependent, suggesting that the ferrite phase recovery was less related to that of the cementite phase.