What is the basic principle of a Rockwell hardness test?
The Rockwell hardness test measures a material's hardness based on the permanent depth of indentation under specific conditions. It uses a two-step load application: a minor (pre) load is applied first to set a reference point, followed by a major load. After removing the major load, the depth of the residual indentation is measured while the minor load is still applied. A shallower indentation depth indicates a higher hardness .