Fatigue Testing of Metallurgically-Bonded EBR-II Superheater Tubes

Journal Article · Thu May 01 04:00:00 EDT 2008 · Journal of Nuclear Materials

DOI:https://doi.org/10.1016/j.jnucmat.2008.02.004· OSTI ID:928078

Totemeier, T C; Wachs, D M; Porter, D L

Fatigue crack growth and impact tests were performed on 2¼Cr-1Mo steel specimens machined from ex-service Experimental Breeder Reactor – II (EBR-II) superheater duplex tubes. The tubes had been metallurgically bonded with a 100 µm thick Ni layer; the specimens incorporated this bond layer. Impact tests were performed at temperatures from –50 to 400°C; cracks propagating from the V-notch were arrested by delamination at the bond layer for all tests with one exception at –50°C. Fatigue crack growth tests were performed at room temperature in air and at 400°C in air and humid Ar; cracks were grown at varied levels of constant ?K. In all conditions the presence of the Ni bond layer was found to result in a net retardation of growth as the crack passed through the layer. The mechanism of retardation was identified as a disruption of crack planarity and uniformity after passing through the porous bond layer. Full crack arrest was only observed in a single test performed at near-threshold ?K level (12 MPa?m) at 400°C. In this case the crack tip was blunted by oxidation of the base steel at the steel-nickel interface.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-99ID13727
• OSTI ID: 928078
• Report Number(s): INL/JOU-07-12275
• Journal Information: Journal of Nuclear Materials, Journal Name: Journal of Nuclear Materials Journal Issue: 1 Vol. 376; ISSN 0022-3115; ISSN JNUMAM
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AIR
CRACK PROPAGATION
Charpy impact
EBR-II
IMPACT TESTS
OXIDATION
STEELS
SUPERHEATERS
TESTING
fatigue crack growth
nickel bonding
superheater