ISO3378 and ISO3878

The hardness of a material is defined as this: the capability of the material resisting the indent made by a diamond indenter.

The method for determining Vickers hardness (HV) is to use a standard pyramid diamond sitting on a square base for penetrating the surface of a sample ant a certain load. The hardness value can be obtained by measuring the diagonal line of the indent. The preload used for cemented carbide is normally 3 kilograms(HV30). This method is widely used in the world.

Rockwell hardness(HRA) is another common method for measuring hardness. This system is to obtain the hardness value via measuring the depth penetrated by a standard conic diamond head.

Attention should be paid to the conversion of one harness to another in view of the difference in the principle for measuring Vickers harness and Rockwell hardness.