Indenters in hardness testing

There are various types of indenters, each designed for specific hardness testing methods and material types. Below are some of the most common types:

Diamond Cone:

These indenters are mainly used in Rockwell hardness testing. The diamond cone has a tip with an opening angle of 120 degrees and is suitable for very hard materials. It offers high precision and long service life due to the extreme hardness of the diamond.

Carbide Balls:

These indenters are used in Brinell and Rockwell hardness testing. They are primarily used for softer materials such as metals and plastics. The balls come in various diameters, typically 1, 2.5, 5, and 10 mm. They offer good wear resistance and even pressure distribution. For Brinell hardness testing, the balls are often made of carbide and are also available in inch sizes.

Diamond Pyramids:

Used in Vickers hardness testing, these indenters have a pyramidal tip with a square base. The pyramid has an opening angle of 136 degrees. For measurements on thin layers and small samples, the Knoop diamond is used. This hardness testing method uses a rhombohedral pyramidal diamond indenter (long edge angle 172.5°; short edge angle 130°).

Non-magnetic Indenters:

For special applications where magnetic interference needs to be avoided, there are indenters made of non-magnetic materials. These are used in environments where the magnetic properties of the test samples could be affected, such as testing electronic components or in combination with magnetic test tables.