There are three types of tests used with accuracy by the metals industry; they are the Brinell hardness test, the Rockwell hardness test, and the Vickers hardness test. Since the definition of metallurgic ultimate strength and hardness are rather similar, it can general be assumed that a strong metal is also a hard metal. The way the three of these hardness tests measure a metal’s hardness is to determine the metal
Resistance to the penetration of a non-deformable ball or cone.
The tests determine the depth which such a ball or cone will sink into the metal under a given load within a specific period of time.