The influence of specimen size on Charpy impact testing of unirradiated HT-9

The effect of specimen size on the impact properties of HT-9 has been studied. The data from precracked and notched-only specimens of HT-9 were used along with previously published data on other steels to develop correlations that predict from subsize specimen data the ductile brittle transition temperature (DBTT) and the upper shelf energy (USE) anticipated for full size specimens. Each correlation is based on physical insight and can be applied equally well to both precracked and notched-only specimens. The correlation for USE works best for fracture energy in a range characteristic of irradiated materials, while a previously published correlation works better for more ductile materials. The DBTT correlation, however, works well on all materials for which sufficient data have been published. (orig.)