The mechanical properties of metals which is Hardness is the resistance to deformation, penetration, abrasion, cutting or distortion.
The hardness of metals can be measured using standard tests where a ball is pressed against the material and the size of the dent is the measurement. The different tests are:

- Rockwell
- Brinell
- Vickers
- etc.
Hardness of a metal can be adjusted by simply using different treatments such as the heat treatment and the cold working. Metals used in structures are formed from a soft state then heated to retain the finished shape.