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Effect of Charpy Striker Configuration on Low- and High-Energy NIST Verification Specimens

Published

Author(s)

Enrico Lucon, Jolene D. Splett

Abstract

Charpy machines can be equipped with strikers having two different configurations, corresponding to an edge radius of 2 mm or 8 mm. Both striker types are covered by ASTM E23 and ISO 148-1. The effect of striker type on Charpy absorbed energy has been extensively investigated in the past, and clear evidence has been published showing that when using 8 mm strikers, absorbed energy (KV) tends to increase for specimens with KV ≥ 200 J. In this paper, we investigate how striking edge radius affects certified values and uncertainties for National Institute of Standards and Technology (NIST) low-energy and high- energy verification specimens. Test data from two low-energy and two high-energy Charpy lots, analyzed in a statistically rigorous manner, were somewhat contradictory and led to the decision to separately certify low-energy and high-energy lots for use with 2 mm and 8 mm strikers. This agrees with previous findings by other NIST researchers, who recommended individual certifications for the two strikers at all energy levels.
Citation
Journal of Research (NIST JRES) -
Volume
123

Keywords

Charpy test, impact hammer, striker edge radius, certified absorbed energy, uncertainties.
Created September 12, 2018