1. The concept and representation of hardness
Hardness refers to the ability of a material to resist the pressing of other hard objects into its surface. The magnitude of the hardness value is a conditional quantitative representation of the degree of softness and hardness of the material. It is not a purely defined physical quantity.
The hardness value depends not only on the material itself, but also on the test conditions and the measurement method, that is, the different hardness measurement methods, and the hardness values measured for the same material are not the same. Therefore, to compare the hardness between materials, the hardness values measured by the same measurement method must be comparable.
The methods commonly used to indicate hardness are as follows:
(1) Shore hardness;
(2) Rockwell hardness;
(3) Mohs hardness;