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Kanayama, Hideyuki*; Hiyoshi, Noritake*; Ogawa, Fumio*; Kawabata, Mie*; Ito, Takamoto*; Wakai, Takashi
Zairyo, 68(5), p.421 - 428, 2019/05
This study presents creep damage assessment method for Mod. 9Cr-1Mo steel by sampling creep testing with thin plate specimen. Tensile creep rupture tests were performed using three different sizes of specimen under two different test environments to verify the creep testing with the thin plate specimen. Time to rupture of Mod. 9Cr-1Mo steel using three different sizes were almost same. In addition, there was no effect of environment on time to rupture. Pre-damaged thin plate specimens were machined from a bulk specimen's gage section that pre-damage test was performed with. Pre-damage based on life fraction rule were 8%, 16% and 25%. No effect of the process of machining pre-damaged specimen on time to rupture was confirmed by verification tests in same test condition as pre-damage test. Stress acceleration creep rupture tests were performed to estimate creep damage assessment. Creep damage assessment by stress acceleration creep rupture tests was sufficiently accurate estimate. Creep damage assessments by Vickers hardness and lath width were compared with the assessment by stress acceleration creep rupture tests to study applicability of these methods.
Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Kurishita, Hiroaki*
no journal, ,
Fracture toughness is an important property when ferritic martensitic steel (FMS) is irradiated and thermally aged. The goal of this study is to develop reasonably miniaturized fracture toughness test technique which can be applied for irradiated or sampled from welded small specimen. In this phase, the capability of miniature 3-point bend (3PB) test technique for evaluating toughness, and the side groove effect on miniatured specimen were confirmed. A miniature 3PB type J test conforming to ASTM 1820 was applied to the PNC-FMS developed for the fast reactor. The effect of the root radius of the side groove that controls the crack propagation was verified for the specimen miniaturized to 5 mm thickness, 3 mm width and 22.5 mm length according to the thickness of the wrapper tube. The crack winded and/or branched with root radius of 0.5 mm, the standard size of ASTM1820. But by making it 0.05 mm, it was possible to control the crack propagation along the side groove. As a result, J
= 300 kJ/m
was obtained, and a prospect of this technique was obtained for the fracture toughness evaluation of the wrapper tube by improving the side groove.
Tanno, Takashi; Yano, Yasuhide; Oka, Hiroshi*; Kurishita, Hiroaki*
no journal, ,
Miniature 3 point bend test was applied to evaluate fracture toughness of ferritic/martensitic steel (PNC-FMS) for fast reactor subassembly wrapper tube. In this work, it was clarified that pre-crack length and open angle of side groove are important to obtain the certain and conservative fracture toughness with miniatured specimen. Finally, the fracture toughness value J
of PNC-FMS could be obtained with miniaturized specimen which can be applied to wrapper tube thickness.
Tanno, Takashi; Fujita, Koji; Yano, Yasuhide; Kurishita, Hiroaki*
no journal, ,
Miniature 3 point bend test was applied to evaluate fracture toughness of ferritic/martensitic steel (PNC-FMS) for fast reactor subassembly wrapper tube. In this work, the anisotropy in toughness of rolled PNC-FMS was successfully confirmed with the specimen which was modified in the geometry. In addition, it was confirmed that data can be obtained with good reproducibility for specimens having plural geometries.
Tanno, Takashi; Fujita, Koji; Shizukawa, Yuta
no journal, ,
no abstracts in English
Tanno, Takashi
no journal, ,
no abstracts in English
Tanno, Takashi; Shizukawa, Yuta; Fujita, Koji
no journal, ,
The evaluation of the fracture toughness of thermal-aged PNC-FMS was conducted using the miniature three-point bending fracture toughness evaluation technique under development. The results implied that although the Charpy impact properties of PNC-FMS after thermal aging for 6000 hours at 600
C degraded, the fracture toughness at room temperature did not degraded. Furthermore, as a result of comparing the cases where fatigue pre-crack was introduced to the test specimen before and after thermal aging, it was found that there was no significant difference under the present thermal aging conditions.