CURRENT STATUS OF SMALL SPECIMEN TECHNOLOGY IN CHARPY IMPACT TESTING

The current status of small-scale specimen technology in Charpy impact testing for ferritic steels is presented, with emphasis on the effect of the notch dimensions (notch depth, notch root radius and notch ang le) on the upper shelf energy (USE) and ductile-to-brittle transition temperature (DBTT). The USE for miniaturized specimens, normalized by Bb(2) or (Bb)(3/2) (B is the specimen thickness, b the ligament size), is essentially independent of notch geometry and has a linear relatio nship with the USE of full size specimens, regardless of irradiation a nd alloy conditions. The DBTT of miniaturized specimens depends strong ly on the notch dimensions; this dependence of the DBTT decreases as t he DBTT of full size specimens increase due to neutron irradiation or thermal aging. These results may be useful in determining the USE and DBTT for full size specimens from these for miniaturized specimens.