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The NIST Charpy V-Notch Verification Program: Overview and Operating Procedures



Christopher N. McCowan, Thomas A. Siewert, D P. Vigliotti


Charpy impact testing is often specified as ,in acceptance test for structural materials, and companies performing acceptance tests are typically required to verify the performance of their impact machine periodically. The procedure for verifying the performance of Charpy impact machines has a physical part and an engineering part. The physical put covers the direct verification of the impact machine, through a detailed evaluation of the machine dimensions, alignment, etc. The engineering part covers the indirect verification of the machine performance, which entails breaking sets of Charpy impact reference specimens. The indirect verification procedure was added about forty years ago, because the use of direct verification procedures alone could not explain some unacceptable differences among the results of the machines tested. Often these differences could be traced to interactions between the machine components and the specimens, and only test-mg with verification specimens could resolve these effects. NIST supplies the impact reference specimens used to indirectly verify the performance of machines according to ASTM Standard E23. The procedures used to conduct this program are the focus of this report.
NIST Interagency/Internal Report (NISTIR) - 1500-9
Report Number


charpy V-notch test, charpy verification program, impact test, verification program


McCowan, C. , Siewert, T. and Vigliotti, D. (2003), The NIST Charpy V-Notch Verification Program: Overview and Operating Procedures, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed May 23, 2024)


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Created September 1, 2003, Updated February 19, 2017