PSI - Issue 19

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2019) 000–000

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ScienceDirect

Procedia Structural Integrity 19 (2019) 284–293

Fatigue Design 2019 Discussion of Effect of Disk Grinding Surface Finish on Fatigue Strength of the Nuclear Component Material Motoki Nakane a *, Yun Wang b , Hisamitsu Hatoh b , Akihiko Hirano c , Kentaro Hayashi d a Hitachi-GE Nuclear Energy, Ltd, 2-2, Omika-cho 5-chome, Hitachi-shi, 319-1221, Japan b Hitachi,Ltd. Research & Development Group, 7-1-1, Omika-cho, Hitachi-shi, 319-1292, Japan a Hitachi-GE Nuclear Energy, Ltd, 1-1, Saiwai-cho 3-chome, Hitachi-shi, 317-0073, Japan d The Kansai Electric Power Co., 5-3, 66 kawasakayama, Nyu, Mihama-cho, Mikata-gun, Fukui-ken 919-1201, Japan Abstract Disk grinding is often used to repair the scratches of the surface of the component and also used to weld toe finish to mitigate undesirable stress concentration. This study investigates the effect of disk grinding surface finish on fatigue strength of the nuclear component materials. In order to achieve this objective, fully reversed tension-compression strain-controlled fatigue tests of disk grinding finished austenitic stainless steel SUS316L plate are conducted at RT in air. Two types of disk grinding directions, which are parallel and perpendicular to the cyclic loading direction, are considered in this study, and fatigue test results are compared to S-N curves obtained by emery polishing and lathe machining finished specimens. It is found that the disk grinding surface finish decreases fatigue strength of materials and, in some cases, the fatigue strength of disk grinding finished materials is lower than that of lathe machining finished specimens with maximum height roughness Rz over 100  m . In order to find out the mechanism of fatigue strength reduction due to the disk grinding, metallographic observations and some measurements such as roughness, hardness and residual stress of the surface are carried out. In addition, the effect of stress concentration and texture of the micro grooves introduced to the surface of the material by disk grinding are discussed. Fatigue Design 2019 Discussion of Effect of Disk Grinding Surface Finish on Fatigue Strength of the Nuclear Component Material Motoki Nakane a *, Yun Wang b , Hisamitsu Hatoh b , Akihiko Hirano c , Kentaro Hayashi d a Hitachi-GE Nuclear En rgy, Ltd, 2-2, Omika cho 5-chome, Hitachi-shi, 319- 221, Jap n b Hitachi,Ltd. Research & D velopment Group, 7 1-1, Omika-cho, Hitachi-shi, 319-1292, J pan a Hitachi-GE Nuclear Energy, Ltd, 1-1, Saiwai-cho 3-chome, Hitachi-shi, 317-0073, Japan d The Kansai Electric Power Co., 5-3, 66 kawasakayama, Nyu, Mihama-cho, Mikata-gun, Fukui-ken 919-1201, Japan Abstract Disk grinding is oft used to repair the scratches of t e surface of the component nd also used to weld toe finish to mitigate undesirable stress concentration. This study nvestigates the eff ct of isk grinding su face finish on fatigue strength of the nuclear component materi l . I order to achieve this objective, fully reversed tension-compression strain-controlle fatigu ests of d sk g inding finished austen tic stainless steel SUS316L plate are conducte at RT in air. Two types of disk grinding di ctions, which are parall l and perpendicular to the cyclic loading directio , are considered in this study, and f tigu te t results are compared to S-N curves obtained by emery pol shing and lathe m chining finished specimens. It is fou d that t disk grinding surface finish decreases fatigue stre gt of materials and, in some cases, the fatigue strength of disk grinding finished materials is lower than that of lathe machining finished specimens with maximum height oughness Rz over 100  m . In order to find out the mechanism of fatigue strength reduction due to the disk grinding, metallographic observations and some measureme ts such as roughness, hardn s and residual stre s of the surface are carrie out. I addition, the effect of stress concentration and texture of the micro grooves introduced to the surface of the material by disk grinding are discussed.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. Keywords: Fatigue strength, Surface finish, Disk griding, Nuclear component material Keywords: Fatigue strength, Surface finish, Disk griding, Nuclear component material

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. * Correspon ing author. Tel.: +81-294-55-4802; fax: +81-294-55-9918. E-mail address: motoki. nakane. ze@hitachi.com * Corresponding author. Tel.: +81-294-55-4802; fax: +81-294-55-9918. E-mail address: motoki. nakane. ze@hitachi.com

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 10.1016/j.prostr.2019.12.031