Estimate of the INMETRO's primary standardization system's best measurement capability for the calibration of brinell hardness reference blocks

This work aims the presentation of the methodology for the determination of the best measurement capability in Brinell hardness of the Hardness Primary Standard Machine installed at the Brazilian National Metrology Institute INMETRO. All calculations and calibrations were carried out in accordance to the methods of the relevant ISO standards and the Guide to the Expression of the Measurement Uncertainty in Hardness. This way, the determination of the strongest influencing factors for the measurements in the Hardness Machine followed the quantitative and statistical methods listed in the Guide. Three hardness reference blocks HBW 2.5/187.5 were used in the hardness ranges 100 (low), 300 (medium) e 600 (high). The best measurement capability was estimated as 1.3 HBW or 0.38%.