Effects of differences in hardness measurement procedures on the traceability chain and calibration process

摘要

Establishment of traceability in hardness measurement is still under discussion at the ISO TC 164 SC 3 subcommittee on hardness testing. Two paths for establishing traceability are proposed for the Rockwell hardness measurement in ISO 6508-1. One way is taking a route to SI units through direct calibration of machine components, and the other way is taking a route to a hardness measurement standard through indirect calibration of machine performance. In addition to this, the difference in hardness measurement procedures between Rockwell and Brinell/Vickers hardness causes further confusion in establishing a traceability chain and an uncertainty evaluation process. This confusion is partly caused by the characteristics of hardness value, i.e. a procedure-dependent property. In this paper, methods used for the establishment of traceability for Rockwell, Brinell and Vickers hardness measurements are discussed based on the concept defined in the VIM.