Assessment of the ductile-to-brittle transition region with 1X-WOL specimens

Several of the nuclear reactor surveillance programs that were started in the early 1970s incorporated some 1X-WOL type fracture mechanics specimens. The 1X-WOL is an early specimen design intended specifically to obtain valid K Ic values on highly embrittled materials. This specimen is now known to...

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Bibliographic Details
Published in:Engineering fracture mechanics 1997-11, Vol.58 (4), p.285-292
Main Authors: Liendo, M.F., Landes, J.D., McCabe, D.E.
Format: Article
Language:English
Subjects:
1X-WOL
A 533 grade B
elastic-plastic
fracture mechanics
KJc
transition temperature
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Summary:Several of the nuclear reactor surveillance programs that were started in the early 1970s incorporated some 1X-WOL type fracture mechanics specimens. The 1X-WOL is an early specimen design intended specifically to obtain valid K Ic values on highly embrittled materials. This specimen is now known to be unsuitable when the material being tested has sufficient fracture toughness to develop elastic-plastic performance. The objective of this project was to evaluate modifications that can be easily made by machining within the hot cell to make the specimens viable for evaluation in the ductileto-brittle transition region using elastic-plastic data development and analyses. Three modifications were tried: (1) remove 7.4 mm from the back face to make the compact specimen H/W ratio of 0.6; (2) a side groove of 25% to decrease the initial remaining ligament strength; and (3) combining side grooving and back face removal, both in lesser amounts, to weaken the remaining ligament strength. An A 533 grade B steel that had already been well documented in toughness properties was selected for this work. The first modification did not work because the remaining ligament was made too small to sufficiently control loss of constraint. The second and third modifications were successful from the standpoint of reproducing the results of the previous material characterization. A recommendation is made for the adoption of the second modification since it is more easily performed as a machining operation in the hot cell.
ISSN:0013-7944
1873-7315
DOI:10.1016/S0013-7944(97)00130-6