Factors affecting the accuracy of the Leeb hardness tester

- Jan 29, 2019-

Factors Affecting the Test Accuracy of the Richter Hardness Tester 1 Errors in Data Conversion The error in conversion to other hardnesses includes two aspects: one is the measurement error of the Richter hardness itself, which involves the dispersion of the test according to the method. And the measurement error for several different models of the Leeb hardness tester. On the other hand, the error caused by the hardness measured by different hardness test methods is compared. This is because there is no clear physical relationship between one of the various hardness test methods, and it is affected by the unreliable measurement in the comparison. 2 Errors caused by special materials The conversion table stored in the hardness tester may cause deviations for the following steel grades: All austenitic steel heat-resistant tool steels and Leysite chrome steel (tool steels) hard materials cause elastic modes. The amount is increased so that the L value is low. This type of steel should be tested on a cross section. Local cooling hardening will cause a high L value. Magnetic steel will have a low L value due to the influence of the magnetic field. Surface hardened steel, soft matrix, will make the L value low. When the hardened layer is larger than 0.8mm (0.2mm for the C-type impact device), the L value will not be affected. Errors in gear detection Under normal circumstances, because the tooth surface is small, the test error is relatively larger than the main working principle of the fruit hardness tester. In this regard, the user can design the corresponding tooling according to the situation, which will help reduce the error. 3 Influence of material elasticity and plasticity The value of Richter is related to the hardness and strength, and is more related to the elastic modulus. The hardness value is the characteristic parameter of the hardness and plasticity of the material, because the composition of the two must be jointly determined. In the elastic part, firstly, it is obviously affected by the E modulus. In this case, when the static hardness of the material is the same, and the E value is different, the material with a low E value, the L value is larger than the error caused by the hot rolling direction. When the hot rolling process is formed, if the test direction is consistent with the rolling direction, the test value is low due to the large 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 should be less than 300 Gauss. 4 Other factors affect the hardness of the pipe. Note: The pipe fittings should be supported by the solid steel tube hardness test method. The test point should be close to the support point and support force. Parallel, the tube wall is thinner and the appropriate core is placed in the tube.