Investigation of Measurement Capability for Charpy V-Notch Specimens Using Typical Measurement Practices

Abstract

Abstract This paper investigates the capability of laboratories and industrial entities to measure the critical dimensions of the Charpy V-notch specimen, as defined in ASTM E23, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials. Notched impact testing is commonly used to evaluate the impact strength and behavior of metals under impact loads at various temperatures. The ASTM Subcommittee E28.07 on Impact Testing became concerned that measuring the dimensions of the V-notch, which is considered critical to the test results, may be less achievable than is generally assumed. An interlaboratory study (ILS) was conducted with ASTM member entities to evaluate the ability of laboratories with various measurement techniques to accurately measure the critical dimensions. This paper evaluates the results of the ILS, which found that the community of laboratories surveyed could not measure all of the critical dimensions with sufficient accuracy to properly reject unacceptable notches. Conclusions and recommendations are provided to improve laboratory performance and provide guidance that may be issued in a revision to ASTM E23. The authors would like to thank the National Institute of Standards and Technology for providing statistical evaluations of the sample data and for the laboratories who participated in the ILS.