Learn About Vickers Hardness Tester

Vickers hardness tester was proposed by R. L. Smith and C. E. Sandland in 1925. Vickers Armstrong, a British company, has trial produced the first hardness tester tested in this way.

Introduction to Vickers hardness tester Vickers hardness tester has more test force, so Vickers hardness tester is also widely used. For other materials or workpieces that can be measured by hardness tester, as long as the roughness of workpiece surface meets the standard. Vickers hardness tester can detect. The Vickers hardness tester presses the workpiece surface through the stepping motor, and then the length of the diagonal of the indentation is measured by the reading microscope. Then Vickers hardness is measured by using a conversion relationship between diagonal and test force. In addition, the Vickers hardness tester measurement software can be installed to display the image through the computer display screen, which is more convenient and fast to operate and measure the hardness value.

Vickers hardness testers are generally classified into three types:

I Vickers hardness tester generally refers to a Vickers hardness testing machine with a maximum load of 10-50kg

II Small load Vickers hardness tester generally refers to the Vickers hardness tester with a maximum load of 5kg

III Micro Vickers hardness tester generally refers to the Vickers hardness testing machine with a maximum load of 1kg

Test principle of Vickers hardness tester

The quotient of the test force divided by the indentation surface area is the Vickers hardness value. Calculation formula of Vickers hardness value: HV = constant × Test force / indentation surface area ≈ 0.1891 f / D2...... where: HV - Vickers hardness symbol; F -- test force (unit: n); D -- arithmetic mean of the two diagonal lines D1 and D2 of the indentation (unit: mm). In practice, the Vickers hardness value can be obtained by looking up the table according to the diagonal length D. The national standard stipulates that the diagonal length range of Vickers hardness indentation is 0.020 ~ 1.400mm. See the schematic diagram of Vickers hardness tester test above.

Classification of Vickers hardness tester tests

Vickers hardness tester is divided into three kinds of tests according to different test forces: 1. Vickers hardness test; 2. Low load Vickers hardness test; 3. Micro Vickers hardness test. The selection of test force depends on the type of sample, sample thickness and expected hardness range. The standard stipulates that the thickness of the sample or test layer shall be at least 1.5 times the diagonal length of the indentation.

Representation of Vickers hardness tester

The Vickers hardness tester is expressed as HV, and the value in front of the Vickers hardness symbol HV is the hardness value, followed by the test force value. The standard test holding time is 10 ~ 15s. However, for non-ferrous metals, it shall not be less than 30 seconds. If the selected time exceeds this range, the holding time shall be noted after the force value. For example:

300hv30 refers to the hardness value of 300 when the test force of 294.2n (30kg) is adopted and the holding time is 10 ~ 15s.

450hv30 / 25 - indicates that the hardness value obtained when the test force of 294.2n (30kg) is used and the holding time is 25s is 450.