Experimental analysis on the influence quantities in the Rockwell C hardness Test

Hardness is a conventional quantity defined by means operational rules in procedures described in the relevant standards. As it is well known, this method gives some problems on the side of uncertainty evaluation. The intrinsic limit is the difficulty to evaluate the sensitivity coefficients of all the influence parameters involved in the measurement procedure. This subject was recently faced in the framework of the European cooperation for Accreditation of Laboratories. IMGC has carried out an experimental analysis, limited to Rockwell C scale, within which a quasi-factorial experimental plan has been used to evaluate the influence of time and velocity of all indentation phases. The results of this analysis could be useful as support for the evaluation of uncertainty, made following the recent International and European guides.