Certified Miniaturized Charpy Specimens for the Indirect Verification of Small-Size Impact Machines

Abstract

Small specimen test techniques are becoming ever more popular as the need increases to characterize mechanical properties by the use of the smallest possible amount of material, because of various restrictions on material availability, irradiation, testing space, and other factors. The National Institute of Standards and Technology (NIST) is currently developing certified miniaturized Charpy V-notch (MCVN) specimens for the indirect verification of small-scale impact testing machines. The same materials used for NIST standard verification specimens are being evaluated at three energy levels (low, high, and super-high). Two specimen types are being investigated, denominated KLST (from the German Kleinstprobe, or “small specimen”) and RHS (reduced half-size). Several instrumented impact tests on miniaturized KLST and RHS specimens of low, high, and super-high energy have been performed and analyzed. The variability of MCVN data has been compared to that of full-size Charpy data from the same lots of test specimens. Although this can be considered as just the preliminary phase of this project, the results indicate that MCVN verification specimens can be used for the indirect verification of small-scale instrumented impact testers, both in terms of absorbed energy and maximum force.