Leeb Hardness Test

The Leeb (also known as an Equotip) test is a modern electronic version of the Scleroscope. It uses a carbide ball hammer that is spring rather than gravity powered. An electronic sensor measures the velocity of the hammer as it travels toward and away from the surface of the sample. The Leeb value is the hammer's rebound velocity divided by the impact velocity times 1000. The result is Leeb hardness from 0 to 1000 that can be related to other hardness scales such as Rockwell and Vickers.

Since the devise is electronic in nature, most instruments are designed to automatically convert from the Leeb number to a more conventional hardness scale. By using a variety of different conversions to suit the modulus of different materials, a wide range of metallic parts can be tested. The main limitations are that the parts must have a good finish and a minimum weight of 5kg. Leeb testers are portable and can be used at different angles as long as they are perpendicular to the test surface.


Leeb test methods are defined in the ASTM A 956 standard.