Brinell - Hardness Test

In 1900, Brinell made his breakthrough and developed hardness testing by using a ball indentation test. In the same year of discovery, he presented this method at the World Exhibition in Paris. This test method has since been known as the Brinell hardness test method. Today this method is used to determine the hardness of materials with heterogeneous structures, soft to medium-hard metals or other materials.

The procedure

In the Brinell hardness test, a test ball made of sintered carbide is pressed onto the material and the impression is then evaluated. Originally, test balls made of hard metal or hardened steel were used. However, since 2006 these are no longer allowed. Since then only balls made of hard metal have been used for hardness testing. The diameter of the test ball is 10 mm, 5 mm, 2.5 mm, 2 mm or even 1 mm. Which ball is used is determined by the thickness of the material that is to be tested. The regular time of pressing is 10 to 15 seconds, depending on the type of material. For very soft materials, the exposure time can also be increased to up to 30 seconds.

In the Brinell hardness test, care is required to ensure that the surface of the material to be tested is smooth, flat and free of impurities. Furthermore, attention must also be paid to the shock-free and vertical penetration of the test ball.

After the compressive load, the vertical and horizontal diameter of the resulting impression is measured. From these two values the average value is determined and this diameter is used in the corresponding calculation of the Brinell hardness. The Brinell hardness is measured in HBW, short for Hardness Brinell Wolframkarbidhartmetall ("Wolframkarbidhartmetall" is German for Tunsten Carbide).