Calibration of hardness testers is carried out at the completion of hardness testers production. Calibration is performed by VNIIFTRI - National Metrological Institute of Russia. For all hardness testers a "Calibration certificate" of the established form is issued, which is included into the hardness tester delivery set.
Calibration of portable hardness testers of "MET" series is performed using hardness reference test blocks by a direct method on all main hardness scales - Rockwell, Brinell, Vickers and Shore.
Calibration on additional scales H1, H2, H3 (for instance, on HL, HBW, HRB, HRN, HRT and other hardness scales), as well as on metals which differ significantly by their properties from steel (for instance, aluminum and copper alloys), is carried out by the user according to the instructions listed in the hardness tester passport.
All hardness testers of "MET" series are introduced into state Register of Measuring Equipment of Russia and have Certificates of Approval of measuring equipment type. Centre MET have licenses for their production.