Performance tests for qualifying metrological Rockwell indenters

Much work has been done on Rockwell diamond indenters to evaluate the relationship between geometry and hardness measurement results. However, it has been observed that the residual after geometrical correction is significant (within ±0,3 HRC). Some investigations on the non-geometric parameters of the Rockwell diamond indenters, as mechanical properties of the diamonds and the soldering of the diamond prism into the holder, were carried out in the past. Recently, using the INRiM primary machine, some experimental tests were carried out to investigate the possibility to correlate the differences on hardness measurements observed using different indenters to the nongeometric characteristics of indenters. The results show that this correlation exists and it can justify the discrepancies