A novel approach of sensitivity coefficients determination for various Rockwell hardness scales using a diamond indenter

Rockwell hardness has approximately 30 scales with different indenters and test forces, and each requiring consideration of uncertainties. Sensitivity coefficients for test forces, cycles, and indenter shapes are experimentally derived, obtaining them for all scales is challenging due to extensive experiments. This study proposes a non-experimental method to determine sensitivity coefficients across Rockwell hardness scales using diamond indenters. Results show that sensitivity coefficients for total and preliminary forces can be calculated from known parameters without experiments. Coefficients for indentation velocity and test force dwell time per scale were estimated from one hardness scale, such as the commonly used C scale. Indenter angle and tip radius coefficients can be estimated via finite element analysis. Reliability of this method was confirmed by comparing uncertainties using coefficients with those determined experimentally in prior studies. Ultimately, this approach enhances the efficiency in determining uncertainty across Rockwell hardness scales, regarding effort saving and improving reliability.