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What Are The Reasons For The Measurement Error Caused By Portable Hardness Testers?
Oct 18, 2018

What are the reasons for the measurement error caused by portable hardness testers?


Let's talk about the following, what are the reasons for the measurement error caused by the portable hardness tester?


1. Errors caused by data conversion


The error when converting the Leeb hardness tester to other hardnesses includes two aspects: one is the measurement error of the Leeb hardness tester itself, which involves the dispersion during the test according to the method and the measurement error for multiple Terry's hardness testers of the same type. . On the other hand, it is the error caused by the hardness measured by different hardness test methods. 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. Error in gear detection


Under normal circumstances, due to the small tooth surface, the test error is relatively large, and the user can design the corresponding tooling according to the situation, which will help reduce the error.


3. Error caused by special materials


The conversion table stored in the hardness gauge may deviate from the following steel grades: all austenitic steel heat-resistant tool steels and Leysite chrome steel hard materials cause an increase in the elastic modulus, resulting in a lower L value. This kind of steel should be tested on the cross section. Local leng but hardening will cause the L value to be higher. The magnetic steel will have a lower L value due to the influence of the magnetic field. Surface hardened steel, soft matrix, will lower the L value, and will not affect the L value when the hardened layer is larger than 0.8mm.


4. Error caused by hot rolling direction


When the workpiece to be tested is formed by the hot rolling process, 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.


5. Influence of material elasticity and plasticity


In addition to the hardness and strength, the Richter value is more related to the elastic modulus. The hardness value is a 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 respect, when the static hardness of the material is the same, and the E value is different, the material having a low E value has a large L value.