In order to test various metal materials with different materials, hardness and thickness, three indenters and three test forces are used in Rockwell hardness test, and the resulting nine combinations correspond to nine scales of Rockwell hardness; The surface Rockwell hardness test uses two indenters and three test forces, and the resulting six combinations correspond to six scales of the surface Rockwell hardness. (small and C-type durometers can be extended to 15 scales of Rockwell hardness or 15 scales of superficial Rockwell hardness, and can be used to test softer metals).
Selection of Rockwell hardness / superficial Rockwell hardness indenters
The indenter shall be selected according to the hardness of the material.
Diamond indenter shall be used for hard materials such as quenched and tempered steel, quenched steel, case hardened steel and cemented carbide. Ball indenter shall be used for soft metal. Small ball indenter is used for hard soft metal, large ball indenter is used for soft metal, and larger ball indenter is used for softer soft metal. See the following table for details:
English
