Brinell hardness test

Diagram depicting the Brinell hardness test: Penetration depth of a ball in a material

The Brinell hardness test is a standardised hardness test but is not suitable for very hard materials or thin surface layers.

The test involves pressing a sintered hard metal ball with a diameter $D$ into the surface of the sample or workpiece to be tested with a defined test Force for a specific period (duration of exposure). Once the force has been removed, the diameter $d$ of the indentation left in the Material by the ball due to plastic deformation (indentation cup) is measured. This is an indication of the material's hardness.

The test conditions must be defined by specifying the hardness number, the test method (ball penetrator material), the ball diameter, the test force and, in the case of test periods longer than 15 seconds, the duration of exposure.