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Experimental operation steps and requirements of Vickers hardness tester
2024-05-23
1. Representation method of Vickers hardness tester
The Vickers hardness tester is represented by HV, with the hardness value before the symbol and arranged in the following order after the symbol:
(1) Selected test force value
(2) Test force retention time (usually not indicated between 10-15)
Example: 640HV30 represents a Vickers hardness value of 640 when maintained for 10-15 seconds under a test force of 294.2N.
640HB30/20 indicates that the Vickers hardness value measured is 640 when maintained for 20 seconds under an experimental force of 294.2N.
2. Measurement program
(1) According to the properties of the material, select the test force in Table 1 for testing. For example, for iron metal materials with surface fire, choose HV30;
(2) Select appropriate standard blocks for verification based on the selected test force;
(3) Adjust the height of the sample to obtain a clear image of the sample surface in the eyepiece;
(4) Rotate the eyepiece so that the indenter is directly above the imaging area;
(5) Press the loading switch, and under the action of the test force, the diamond will load the surface of the sample;
(6) Uninstall after holding for a certain period of time;
(7) Rotate the eyepiece to observe a clear diagonal and read the length of the diagonal on the eyepiece;
(8) Read the corresponding Vickers hardness value from the GB/T4340.1-1999 table based on the average diagonal value L and the selected test force A.
3. Experimental environment requirements
(1) The experiment is generally conducted at room temperature of 10 ° C~35 ° C, and for laboratories with strict temperature requirements, it is 23 ° C+;
(2) Horizontal installation of Vickers hardness tester on a stable foundation;
(3) The entire environment has no vibration, no corrosive media, and a relative humidity of<65%.
4. Sample requirements
(1) The surface of the sample should be flat and smooth, free of oxides and foreign impurities, and free of grease. The surface roughness should meet the requirements of Table 2.
(2) Requirements for indentation distance of different materials
The distance between the centers of adjacent indentations on steel, copper, and copper alloys is greater than three times the diagonal of the indentation.
The distance between adjacent indentation centers for light metals, lead, tin, and alloys is 6 times greater than the diagonal of the indentation.
