Miniaturized Charpy Specimens for the Indirect Verification of Small-Scale Charpy Machines: Initial Qualification Phase (Revised)

Publication Title: Miniaturized Charpy Specimens for the Indirect Verification of Small-Scale Charpy Machines: Initial Qualification Phase (Revised)

Subject: Impact testing
Metals
Indirect verification
KLST
MCVN
Miniaturized Charpy specimens
Small specimens
Small-scale impact testers

Government Author: Commerce Department, National Institute of Standards and Technology (NIST) .

Abstract: Small specimen test techniques become ever more popular as the need increases to characterize mechanical properties by use of the smallest possible amount of material, due to various restrictions on material availability, irradiation, testing space, and other factors. NIST is currently developing reference 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 lot of test specimens. Although this can be considered 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. Additional aspects have also been investigated, such as the influence of shear lip symmetry and specimen fracture on absorbed energy and the correlation between miniaturized and full-size Charpy data.