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Influence of Side-Groove Depth and Heat Treatment on Super-High Energy Charpy Specimens of 9310 Steel



Enrico Lucon


NIST provides certified reference Charpy specimens to companies and laboratories around the world for the indirect verification of impact machines in accordance with ASTM E23. Specimens are available at three energy levels, low (15 J at 40 C), high (100 J at -40 C), and super-high (200 J at room temperature). Specimens of this latter energy level have been out of stock from the late 2000s until the late 2010s, when specimens of AISI 9310 steel were found to be suitable for standardization, provided they were side-grooved in order to prevent the formation of shear lips. This study was aimed at establishing an optimal combination of heat treatment (specifically, final tempering temperature) and side-groove depth for Charpy specimens of 9310 steel, and was conducted by testing almost 900 specimens corresponding to six different combinations. As a result of this study, a recommendation for the heat treatment and side-groove depth of future super-high energy specimen lots was formulated.
NIST Interagency/Internal Report (NISTIR) - 8424
Report Number


ASTM E23, final tempering temperature, NIST Charpy Machine Program, shear lips formation, side-groove depth, super-high energy Charpy specimens


Lucon, E. (2022), Influence of Side-Groove Depth and Heat Treatment on Super-High Energy Charpy Specimens of 9310 Steel, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed May 26, 2024)


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Created June 8, 2022, Updated November 29, 2022