The error of Leeb hardness meter

The error of Leeb hardness and other hardness tester includes two aspects,on the one hand, the measurement error of the Leeb hardness tester for metalic materialwhich involves the dispersion when tested by the method and the measurement error for multiple Leeb hardness testers of the same model. On the other hand, it is to compare the hardness errors measured by different hardness test methods. This is due to the fact that there is no clear physical relationship between one of the hardness test methods, and it is due to the unreliable measurement in comparison.

The conversion is stored in the digital hardness tester,which may deviate from the following steel grades, All austenitic steels have heat-resistant tool and clayless chromium, tool steels of hard materials will cause an increase in the elastic modulus, thus making L  value is low. This type of steel should be tested in cross-section. Local cooling hardening will cause high L-value magnetic steel due to magnetic field, will make L value low. Surface-hardened steels shore hardness tester with a soft matrix will have a low L-value. When the hardened layer is greater than 0.8 mm (0.2 mm for a C-type impact device), it does not affect the L-value.

Under normal circumstances, due to the small tooth surface, the test error of hardness meter for pencil is relatively large, for which the user can design the corresponding tooling according to the situation, which will help reduce the error. In addition to hardness and strength, the Richter scale is related to the elastic modulus. The hardness value is a characteristic parameter of the material hardness and plasticity, because the two components must be jointly determined.In the elastic part, the first is obviously influenced by the E modulus. In this respect, when the ultrasonic hardness meter of the material is the same, and the E value is different, the material with a low E value has a larger L value.

When measured workpiece is formed by the hot rolling process, if the test direction of ultrasonic pencil hardness meter is consistent with the rolling direction, the test value will be lower due to the larger elastic modulus E, so the test direction should be perpendicular to the hot rolling direction. For example: When measuring the hardness of a cylindrical section, it should be tested in the radial direction. (General cylindrical hot rolling direction is axial). The influence of sample weight, roughness and thickness shall be less than 300 Gauss. The hardness of the test piece shall be less than 300 gauss. When measuring the hardness of the pipe fittings, attention shall be paid: the pipe shall pay attention to the stable support, the test point shall be close to the support point and parallel to the support force, and the pipe wall shall be thinner