For metallic materials, the different scales of measurement are quite varied. The best known and most used ones are the Vickers
or Brinell scales.
The hardness of a material means the resistance of a surface of the sample to the penetration of a harder body, for example the ball or the tip (or indenter) of a Hardness Tester. If it withstands it well, it is said to be hard; otherwise, it is said to be soft.
Specifically, hardness is measured by correlating the size of the indentation (Vickers, Knoop and Brinell hardness) or its depth (Rockwell hardness).
This indentation is created using a Hardness Tester that applies the load via the indenter onto the sample to be tested.
Hardness measurements are standardised. Regarding hardness tests and their reference standards::
- Vickers: ISO 6507 and/or ASTM E384
- Knoop: ISO 4545 and/or ASTM E384
- Rockwell: ISO 6508 and/or ASTM E18
- Brinell: ISO 6506 and/or ASTM E10
A distinction is generally made between micro-hardness (tests with loads < in kgF) and hardness or macro-hardness for higher loads. Below, we will specifically discuss the different hardness tests and the equipment for conducting them.