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Takano, Katsutoshi; Koizumi, Norikiyo; Serizawa, Hisashi*; Tsubota, Shuho*; Makino, Yoshinobu*
Yosetsu Gakkai Rombunshu (Internet), 33(2), p.126 - 132, 2015/06
A radial plates (RP), which is used in Toroidal field (TF) coil in ITER, is significantly large, such as 13 m height and 9 m wide, but thin, such as 10 cm thick, and are made of full-austenite stainless steel. Even though they are very large structures, high manufacturing tolerances are required. In addition, it is required that each RP is fabricated every three weeks. Therefore, the authors develop efficient manufacturing methods of RP. The laser welding is selected as a welding method of RP. But the development of the high power laser welding technology is necessary to avoid hot cracking of the materials used for RP, namely full austenite stainless steel with high nitrogen content. The authors carried out trial aiming at an application of the laser welding to RP. As a result, it is effective to optimize the angle of inclination of the weld head. It also seems sensitivity of hot cracking can be less by optimizing the chemical composition of materials to use for RP. It was therefore demonstrated that the application of the laser welding technology in the full austenite stainless steel.
Koizumi, Norikiyo; Matsui, Kunihiro; Hemmi, Tsutomu; Takano, Katsutoshi; Chida, Yutaka; Iguchi, Masahide; Nakajima, Hideo; Shimada, Mamoru*; Osemochi, Koichi*; Makino, Yoshinobu*; et al.
IEEE Transactions on Applied Superconductivity, 22(3), p.4200404_1 - 4200404_4, 2012/06
Times Cited Count：9 Percentile：47.58(Engineering, Electrical & Electronic)JAEA started sub- and full-scale trials to qualify and optimize manufacturing procedure of ITER TF coil from March, 2009. As major outcome of these trials, automatic winding system with accuracy in conductor length measurement of 0.01% has been established and the elongation of the conductor length due to heat treatment was measured to be 0.06%. To confirm validity of these outcomes, the authors carried out winding of a one-third scale dummy double pancake (DP), followed by its insulation and impregnation trial, and, in addition, heat treatment of one-third scale DP with real a TF conductor. The details about these trials are described in the other paper. The authors also performed trial manufacture of full scale RP and CPs for dummy double pancake, which will be made in near future. The full scale RP is manufactured by machining 10 segments in parallel to shorten machining duration and joining each segment by welding. In our trial manufacture of the full scale RP, hot-rolled SS316LN plates are machined to a final dimension, namely without additional material, and these segments are laser-welded. From these trials, manufacturing procedure of a thick hot-roll SS316LN plate is qualified and machining procedure is established, while more optimization may be necessary to achieve the required schedule and cost.
Koizumi, Norikiyo; Matsui, Kunihiro; Shimizu, Tatsuya; Nakajima, Hideo; Iijima, Ami*; Makino, Yoshinobu*
Teion Kogaku, 47(3), p.186 - 192, 2012/03
In the ITER TF coil, cover plates (CP) are welded to teeth of a radial plate (RP) to fix a conductor in the groove of the RP. Though total length of welds is approximately 1.5 km and height and width of an RP are 14 m and 9 m, respectively, the welding deformation better than 1 mm in local distortion and several milli-meters in in-plane deformation is required. Therefore, laser welding is used for the CP welding to reduce welding deformation as possible. However, a gap of a welding joint is expected to be 0.5 mm at the maximum. Therefore, at first, the laser welding technique to enable welding on the gap of 0.5 mm width is developed in this study. Using this technology, CP welding trial using an RP mock was successfully performed. The achieved flatness is 0.6 mm. In addition, the welding deformation of a full-scale RP is estimated by the analysis using the inherent strain. The results show that the flatness of 1 mm is achievable and profile of 5 mm can be achieved. Since the in-plane deformation can be corrected by welding somewhere to originate artificial welding deformation, it is confident that the required tolerance of several milli-meters in in-plan profile is achievable.
Takano, Katsutoshi; Koizumi, Norikiyo; Shimizu, Tatsuya; Nakajima, Hideo; Esaki, Koichi*; Nagamoto, Yoshifumi*; Makino, Yoshinobu*
Teion Kogaku, 47(3), p.178 - 185, 2012/03
In the ITER TF coil, the tight tolerances of 1 mm in flatness and a few mm in profile are required in manufacturing a radial plate (RP), although the height and width of an RP are 13 m and 9 m, respectively. In addition, since cover plates (CP) should be fitted to a groove of an RP with tolerance of 0.5 mm, the tight tolerances are also required to a CP. Thus, we can conclude that the manufacturing procedure of the RP and CP has been demonstrated.
Shiihara, Katsunori*; Makino, Yoshinobu*; Ogawa, Tsuyoshi*; Asai, Satoru*; Kanahara, Toshio*; Senda, Ikuo*; Okuno, Kiyoshi; Koizumi, Norikiyo; Matsui, Kunihiro
Proceedings of 26th International Congress on Applications of Lasers & Electro-Optics (ICALEO 2007) (CD-ROM), p.316 - 324, 2007/10
The toroidal field coil is manufactured as one of superconducting coil systems in the ITER. For welding the cover plate of TF coil, the prevention of the thermal effect on the coil and the deformation of the whole coil are required. Moreover, the application of high efficient welding is required in consideration for the productivity. Therefore, laser-arc hybrid welding process was investigated for the application to the cover plate welding, because its process is superior in the tolerance of the joint gap and the ease of the control for the heat input. In the experiment, it was confirmed that the application of laser-arc hybrid welding with the double gas shielding for high concentration arc and the filler wire for controlling the deposit amount is effective in the joint gap up to 0.8mm. Besides, twin spot laser head with the arc was developed in order to weld the both sides of cover plate simultaneously. By the optimization of welding condition for twin spot laser-arc hybrid welding process, it was confirmed to be effective in the prevention of the gap movement during welding and the acquisition of the proper penetration without the weld defect. Finally, the effectiveness of laser-arc hybrid welding for the welding deformation and the weldability on the quality was verified by the scale model test with the actual shape.
Asai, Satoru*; Ogawa, Takeshi*; Makino, Yoshinobu*; Shiihara, Katsunori*; Senda, Ikuo*; Okuno, Kiyoshi; Koizumi, Norikiyo; Matsui, Kunihiro
no journal, ,
no abstracts in English
Ogawa, Tsuyoshi*; Asai, Satoru*; Makino, Yoshinobu*; Shiihara, Katsunori*; Senda, Ikuo*; Okuno, Kiyoshi; Koizumi, Norikiyo; Matsui, Kunihiro
no journal, ,
no abstracts in English
Asai, Satoru*; Ogawa, Tsuyoshi*; Makino, Yoshinobu*; Shiihara, Katsunori*; Senda, Ikuo*; Okuno, Kiyoshi; Koizumi, Norikiyo; Matsui, Kunihiro
no journal, ,
no abstracts in English
Makino, Yoshinobu*; Goto, Yu*; Kanahara, Toshio*; Nagamoto, Yoshifumi*; Osemochi, Koichi*; Koizumi, Norikiyo; Takano, Katsutoshi; Matsui, Kunihiro; Nakajima, Hideo
no journal, ,
The toroidal field coil is manufactured as one of superconducting coil systems in the ITER. For welding the radial plate of TF coil, the prevention of the welding deformation and the high quality of the joints among the radial plates are required. Moreover, the application of high efficient welding is required in consideration for the productivity. Therefore, 10kW high power laser welding process was investigated for the application to the radial plate welding, because its process is superior in the productivity for the joints and the ease of the control for the heat input. In the experiment, it was confirmed that the application of the high power laser welding with the 6 axes industrial robots is effective in the welding deformation less than approximately 0.5mm for the small model. Finally, the effectiveness of the laser welding for the welding deformation and the weldability on the quality was verified by the real scale test with the actual shape.
Makino, Yoshinobu*; Goto, Yu*; Kanahara, Toshio*; Nagamoto, Yoshifumi*; Osemochi, Koichi*; Koizumi, Norikiyo; Takano, Katsutoshi; Matsui, Kunihiro; Nakajima, Hideo
no journal, ,
no abstracts in English
