The hardness characteristic of a material is its ability to resist indention, penetration, scratching, and plastic deformation hence determining its permanent depth. A hardness test is, therefore, a mechanical analysis used, particularly on metal sheets and metal plate materials. There are different forms of calibrating this test, thus, used to measure both material properties and functionality.
The testing method depends on the characteristics and the indention dwell-time of the testing material. There are mainly four most common types of hardness testing methods;
* Brinell test
* The Rockwell test
* The Vickers test
* The Knoop test
The four methods involve the test material surface indenting and calculated by recording and comparing the amount of force applied on the material to specific geometrical attributes of the indentation, i.e. depth (diameter) or the surface area.
The Testing Procedure
Physically, the magnitude of the indentation left by the testing equipment recording as finding. The lower the indention readings, the harder the material tested. A specimen material, i.e. metal or sheet plate of a recognized load, is pressed for a specific period (dwell-time). The test (indention on the polished surface of the test material) readings are taken mainly recorded through an optical microscope.
With all the above testing methods, one is confident enough on any level of testing one can take, from shallow to deep indention, i.e. aluminum foil, glass, ceramics or steel metals. For perfect results, the testing materials should be irregular or rather be in a regular shape to get a precise reading.