5-9 September 2016
Prague Congress Centre
Europe/Prague timezone

P1.183 Tensile properties of F82H steel after aging at 400 to 650°C for 30,000 h

5 Sep 2016, 14:20
1h 40m
Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Foyer 2A (2nd floor), 3A (3rd floor)

Prague Congress Centre

5. května 65, Prague, Czech Republic
Board: 183
Poster I. Materials Technology P1 Poster session

Speaker

Takuya Nagasaka (National Institute for Fusion Science)

Description

A reduced-activation ferritic steel, F82H steel, is the primary candidate structural material for fusion blanket. It has been clarified that long term aging degrades both strength and ductility due to precipitation of Laves phase (Fe2W) and other changes in microstructure. In order to evaluate the degradation and to clarify its mechanisms, the present study analyzed the tensile properties of F82H after long term aging at the operation temperature. The material used was F82H-IEA heat with a composition of Fe- 7.71Cr- 1.95W- 0.091C -0.16V -0.02Ta -0.11Si -0.16Mn -0.002P -0.002S -0.006N. The final heat treatment conditions were normalizing at 1040°C for 40 min and then tempering at 750°C for 1 h. F82H was aged from 400 to 650°C for 1,000 to 30,000 h. Type SS3 tensile specimens with a gauge size of 5 x 1.2 x 0.75 mm were machined before and after the aging. Tensile tests at room temperature (RT) were conducted in the air, while high temperature tests were perfomed from 400 to 650°C in a vacuum. Ultimate tensile strength (UTS) at RT before aging was 673 MPa. UTS after aging at 500, 550, 600 and 650°C for 1,000 h was 653, 652, 651 and 583 MPa, respectively. Since the scattering of the strength is about 50 MPa in tensile tests, only the change, - 90 MPa, in UTS at 650°C is recognized as obvious degradation. Degradation more than -50 MPa was observed at 650°C for 3,000 h aging, while it was detected at 600 and 650°C for 10,000 and 30,000 h aging. In conclusion, the degradation ranged from -57 to -176 MPa, and increased with increasing aging temperature and time. The mechanisms for the change in tensile properties will be discussed.

Co-authors

Akio Sagara (National Institute for Fusion Science, Toki, Gifu 509-5292, Japan) Hideo Sakasegawa (Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212, Japan) Hiroyasu Tanigawa (Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212, Japan) Masami Ando (Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212, Japan) Takeo Muroga (National Institute for Fusion Science, Toki, Gifu 509-5292, Japan) Takuya Nagasaka (National Institute for Fusion Science, Toki, Gifu 509-5292, Japan) Teruya Tanaka (National Institute for Fusion Science, Toki, Gifu 509-5292, Japan)

Presentation Materials

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