The principle of Leeb hardness tester is that the ratio of bounce speed and impact speed is converted into digital signal by electromagnetic induction coil to reflect the hardness value. When the workpiece is impacted, when the workpiece is small or the workpiece is unstable, the elastic modulus changes, which will cause hardness. The inability to display or the low hardness value proves that the elasticity has been lost, and the force of the rebound is absorbed by the workpiece.
Mainly in the measurement of hollow parts, thin plates and soft metal materials, the following provides several ways to reduce the error of the Leeb hardness tester:
1. For hollow materials such as pipes, it is difficult but not very effective to use horizontal surfaces or impact end surfaces, or to add supports in the wall. Measuring surface diameter 20mm-100mm on the Leeb hardness tester requires an optional surface support ring.
2. For sheet thicknesses above 5 mm (workpieces under 5 mm, try not to use the Leeb hardness tester). Measure the grease on the back side of the measurement. Coat well with the platform. Compress the intermediate air and do not move it. Do not apply too much butter.
3. To ensure the finish of the metal material, it should be less than 7um in RA, the better the surface finish, the higher the accuracy of the hardness value.
4. The solid cylinder ensures the stability of the workpiece, and the smaller cylinder is preferably added to the V stage.
5. When using the Leeb hardness tester to measure the Brinell hardness, the surface roughness, weight, and coupling degree of the workpiece should be improved. If the surface roughness is poor and the workpiece is not easy to handle, the G-type impact device is the best choice.