Abstract
An investigation has been conducted on the influence of the through-thickness sampling position on the tensile and fracture toughness properties of reactor pressure vessel forgings, using material from two actual pressurized water reactor vessels. The aim was to quantify the safety margins entailed by
extracting surveillance samples from the 1/4T and 3/4T positions, as recommended by the current legislation.
For each forging, seven layers have been considered: Inner surface, 1/8T, 1/4T, 1/2T, 3/4T, 7/8T, and outer surface; for each position, two tensile tests at room temperature and 16 fracture toughness tests in the ductile-to-brittle transition region have been performed. In terms of tensile properties, for both forgings
the strength is higher at the surfaces than in the centre, while ductility (elongations and reduction of area) is substantially unaffected. For both materials, fracture toughness is better at the surfaces than in the central portion, although differences in terms of Master Curve reference temperatures are statistically not
relevant at the 95 % confidence level. This effect is more pronounced for one of the materials, due to the larger amount of material removed with respect to the original heat-treated forging, and is qualitatively confirmed by metallographic observations.
Details
Original language | English |
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Pages (from-to) | 1-9 |
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Journal | Journal of ASTM International |
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Volume | 7 |
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Issue number | 1 |
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Publication status | Published - Jan 2010 |
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Event | Joint ASTM-ESIS Symposium on Fracture and Fatigue - ASTM, Vancouver, Canada Duration: 1 May 2009 → 1 May 2009 |
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