Characterizing material properties by the use of full-size and subsize Charpy tests: An overview of different correlation procedures

A total of 565 instrumented impact tests (232 performed on full-size and 333 on subsize Charpy-V specimens) have been analyzed in order to derive meaningful assumptions on the correlations existing between test results obtained on specimens of different size. Nine materials (pressure vessel steels) have been considered, in both the asreceived and irradiated state, for a total of 19 conditions examined. For the analysis of data, conventional as well as novel approaches have been investigated; the former ones, based on a review of the existing literature, include predictions of upper-shelf energy (USE) values by the use of normalization factors (NF), shifts of index temperatures related to energy/lateral expansion/shear fracture levels, and a combination of both approaches (scaling+shifting of energy curves). More original and recent proposals have also been verified, available in the literature but also proposed by SCK·CEN in the frame of enhanced surveillance of nuclear reactor pressure vessels. Conclusions are drawn regarding the applicability and reliability of these methodologies.