Manual

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4.4 Surface curvature and selecting the right support ring

When the radius of the surface curvature is ˂30 mm, we recommend you to use the smaller

support ring with an outer diameter of approx. 14 mm. If the radius of the surface curvature is ˃30

mm, the larger support ring with an outer diameter of approx. 20 mm should be used.

5 Background information

5.1 Measuring principle

Measurements are made in line with the Leeb principle, i. e. an impact body that has a certain

weight hits the surface of the material to be tested at a given speed. The speed of the impact and

of the rebound of the impact body will then be measured 1 mm above the point of impact.

Formula: HL = 1000 * B / A

HL = Leeb hardness

B = Rebound speed

A = Impact speed