Abstract
This report describes the results of suplementary comparison of National primary hardness machines on the Brinell scales of four national metrological institutes. The report presents the results of measurements of participants, the expanded uncertainty of hardness measurements on Brinell scales, the reference values of comparisons, expanded uncertainties of the reference values, criteria of the correlation of the measurement results and proposed minimum expanded uncertainties of hardness measurements on Brinell scales for CMC lines. Main text To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ . The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).