On macrohardness testing of Al-7 wt.% Si–Mg alloys: I. Geometrical and mechanical aspects

Geometrical aspects of Rockwell hardness testing have been reviewed. Using data obtained by optical measurements and the piling-up model of Hill et al., indentation diameter for three Rockwell scales (B, F and K) have been calculated for cast Al-7 wt.% Si–Mg alloys. Empirical relationships between Rockwell hardness number and indentation diameter have been introduced. When compensated for load and indenter diameter, all three scales produce the same mean pressure.