Rockwell hardness test

Diagram depicting the Rockwell hardness test

The Rockwell hardness test measures a material's hardness based on the penetration depth of an indenter.

The process can be automated and is therefore primarily used in the manufacturing sector for rapid hardness testing. It is not suitable for soft, flexible materials.

The indenter, a 120° diamond cone, subjects the sample to a load. The two-stage test method uses two different loads - a minor load (preload) and a major load (the actual test Force) which, depending on the material, acts for around two to eight seconds. This is followed by elastic recovery. with the residual penetration depth a measure of the Rockwell hardness.

Hard metal balls are sometimes also used as indenters.