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Iyota, Muneyoshi*; Matsuda, Tomoki*; Sano, Tomokazu*; Shigeta, Masaya*; Shobu, Takahisa; Yumoto, Hirokatsu*; Koyama, Takahisa*; Yamazaki, Hiroshi*; Semba, Yasunori*; Ohashi, Haruhiko*; et al.
Journal of Manufacturing Processes, 94, p.424 - 434, 2023/05
Times Cited Count：3 Percentile：83.33(Engineering, Manufacturing)Shobu, Takahisa; Shiro, Ayumi*; Muramatsu, Toshiharu*
SPring-8/SACLA Riyo Kenkyu Seikashu (Internet), 9(5), p.318 - 323, 2021/08
Laser welding has already been put into practical use for various metal materials because the irradiation area is very small and the control is easy. In this study, we evaluated strain, stress, deformation, etc. near the processing affected area by high-energy synchrotron radiation X-ray diffraction method, which is one of the problems of laser welding of different materials that are expected to be put into practical use. As a result of internal deformation measurement of the bonding of dissimilar materials of copper and iron, it was confirmed that the copper side with a high coefficient of linear expansion was hardly deformed, strong tensile strain on the iron side, and a plastic deformation region on the heat-affected zone. In addition, a retained austenite phase, which is thought to be caused by the mixture of copper, was observed in the plastic deformation region of iron, and further problems were clarified in the evaluation of material strength in the mixed metallic materials.
Wakai, Takashi; Kobayashi, Sumio; Kato, Shoichi; Ando, Masanori; Takasho, Hideki*
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 7 Pages, 2017/07
This paper describes a thermal fatigue test on a structural model with a dissimilar welded joint. In the present design of JSFR, there may be dissimilar welded joints between ferritic and austenitic steels especially in IHX and SG. Creep-fatigue is one of the most important failure modes in JSFR components. However, the creep-fatigue damage evaluation method has not been established for dissimilar welded joint. To investigate the evaluation method, structural test will be needed for verification. Therefore, a thermal fatigue test on a thick-wall cylinder with a circumferential dissimilar welded joint between Mod.9Cr-1Mo steel and 304SS was performed. Since the coefficients of thermal expansion of these steels were significantly different, buttering layer of Ni base alloy was installed between them. After the completion of the test, deep cracks were observed at the HAZ in 304SS, as well as at HAZ in Mod.9Cr-1Mo steel. There were many tiny surface cracks in BM of 304SS. According to the fatigue damage evaluation based on the finite element analysis results, the largest fatigue damage was calculated at HAZ in 304SS. Large fatigue damage was also estimated at BM of 304SS. Fatigue cracks were observed at HAZ and BM of 304SS in the test, so that analytical results are in a good agreement with the observations. However, though relatively small fatigue damage was estimated at HAZ in Mod.9Cr-1Mo steel, deep fatigue cracks were observed in the test. To identify the cause of such a discrepancy between the test and calculations, we performed a series of finite element analyses. Some metallurgical investigations were also performed.
Akita, Koichi; Shibahara, Masakazu*; Ikushima, Kazuki*; Nishikawa, Satoru*; Furukawa, Takashi*; Suzuki, Hiroshi; Harjo, S.; Kawasaki, Takuro; Vladimir, L.*
Yosetsu Gakkai Rombunshu (Internet), 35(2), p.112s - 116s, 2017/06
