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Causes of measurement errors in portable hardness testers
Oct 26, 2018

Causes of measurement errors in portable hardness testers


Let's take a look at the following small series, which causes the measurement error of the portable hardness tester.


1. Error in gear detection


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


2, the error caused by special materials


The conversion table stored in the hardness tester may deviate from the following steel grades:


All austenitic steel heat-resistant tool steels and Leysite chrome steel (tool steel) hard materials cause an increase in the modulus of elasticity, resulting in a lower L value. This kind of steel should be tested on the cross section. Local cooling hardening will cause the L value to be high. The magnetic steel will have a low L value due to the influence of the magnetic field.


Surface hardened steel, soft matrix, will lower the L value. When the hardened layer is larger than 0.8mm (0.2mm for C-type impact device), the L value will not be affected.


3. Errors caused by data conversion


The error in conversion of Richter hardness to other hardness includes two aspects: on the one hand, the measurement error of the Leeb hardness tester itself, which involves the dispersion in the test according to the method and the measurement error for several pairs of the same type of Leeb hardness tester. 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 the various hardness test methods, and it is affected by the unreliable measurement in the comparison.


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