The Vickers hardness testing involves a flexible test procedure used to determine both the micro and macro hardness of a sample. It involves an optical testing technique in which the size of the indentation left by the indenter is established and indicates the hardness of sample material. The penetrator that is utilized comprises a four-sided diamond pyramid at an angle of 136 degrees. It consists of a wide range of load and it is appropriate for several applications including testing the hardness of metals, ceramics, and other materials.
Before testing any specimen on the testing equipment, ensure the surface is prepared as per the load used.
For microhardness testing, ensure that the load that is used is less or equivalent to 1 kgf and ensure the surface is either electropolished or mechanically polished.
When testing for macro hardness, ensure that the loads used are greater than 1 kgf and the surface must be grounded.
The Vickers hardness testing procedure is as follows:
- Place the equipment to the required stage of the test load.
- Carefully, position the sample on the testing surface
- Adjust the objective towards the “set” position.
- Adjust the handwheel towards the clockwise direction to ensure the sample is sharply focused on the front screen.
- Then take the inventor to the “set” position and adjust the loading, dwell, and unloading cycle.
- Adjust the objective to the “set” position again.
- Now the indentation is left on the front side of the screen.
- Then, take measurements of the diagonals in both axes of the impression and document them.