Hardness test methods
BrinellRockwell (DIN EN ISO 6508)
Principle:
The indenter (diamond cone or hardmetal ball) is pressed into the sample in two steps (with a preliminary test force, which determines the starting point of the indentation depth, and the additional test force). The remaining indentation depth h is measured after the additional test force under preliminary test force has been removed.
Measurement equation:
h in mm
Values of the constants N and S as well as indenter and application fields as a function of the hardness scale
| Hardness scale | Indenter | N | S | Application field |
| HRA | Diamond cone | 100 | 0.002 | Hard metals, surface-hardened parts with thin hardened layers, thin sheets (≥ 0.4 mm) |
| HRB | Ball 1.5875 mm | 130 | 0.002 | Non-ferrous metals, structural steels |
| HRC | Diamond cone | 100 | 0.002 | Hardened and tempered steels |
| HRD | Diamond cone | 100 | 0.002 | Surface-hardened parts with hardened layers of mean thickness |
| HRE | Ball 3.175 mm | 130 | 0.002 | Cast iron, Al and Mg alloys, bearing metals, plastics |
| HRF | Ball 1.5875 mm | 130 | 0.002 | annealed Cu alloys, thin sheets (≥ 0,6 mm) |
| HRG | Ball 1.5875 mm | 130 | 0.002 | phosphorous bronze, beryllium copper, malleable cast iron of not too high hardness |
| HRH | Ball 3.175 mm | 130 | 0.002 | Al, Al, Zn, Pb, grinding stones |
| HRK | Ball 3.175 mm | 130 | 0.002 | Bearing metals and other metals of very low hardness |
| HRN | Diamond cone | 100 | 0.001 | Like HRA, HRC, HRD, but for especially thin hardened layers resp. sheets |
| HRT | Ball 1.5875 mm | 100 | 0.001 | Like HRE, HRF, HRG, but for especially thin sheets (up to 0.25 mm) |
| HRY | Ball 12.700 mm | 100 | 0.001 | For metals with very low hardness and for very thin layers, e. g. thin bearing metal linings, sintered metals |