Dispersion in the values of reference Rockwell hardness gauges

Abstract

1. The sagging in gauges increases with a rising number of indentations, with the exception of gauges 9, 9′, and 10 (Fig. 3). 2. The maximum sagging decreases with a rising thickness of gauges (Table 3). 3. The mean HRC value of every 40 indentations does not change with the number of applied indentations (Table 2). 4. The maximum dispersion and the quadratic mean error increases with a rising number of indentations only in thin gauges (6, 6′ and 7′). In the remaining gauges the maximum dispersion even decreases slightly. 5. No direct relationship has been established between the maximum sagging of gauges and maximum dispersion. Gauges with a maximum dispersion (6′ and 10) have the roughest clusters of cementite over a background of martensite.