BS EN ISO 6507-2:2018 pdf free
BS EN ISO 6507-2:2018 pdf free.Metallic materials – Vickers hardness test
The system for measuring the diagonal of the indentation shall be verified at each magnification and for each incorporated line scale to be used. When an individual scale is used in two perpendicular axes, it shall be calibrated in both orientations. Measurements shall be performed using a calibrated stage micrometer: The maximum expanded uncertainty of the distances between the line intervals on the stage micrometer shall be as indicated in Table 3.
Measurements shall be made at a minimum of four evenly spaced intervals, arranged centrally in the field of view, covering each working range. Three measurements shall be made at each of the evenly spaced intervals. The maximum permissible error of each of the three measurements at each interval shall be as indicated in Table 3.
The testing machine shall be verified by testing reference blocks that have been calibrated in accordance with ISO 6507-3. The blocks shall have been calibrated using the same test forces that the machine will use for future testing. When verifying more than one test force, at least two reference blocks shall be selected from the hardness ranges specified below for each test force that the machine will be verified.
The set of blocks needed for verifying the machine for all the test forces shall be chosen so that at least one reference block from each hardness range is used for the verifications. When verifying testing machines using only one test force, three reference blocks shall be used, one from each of the three hardness ranges specified below. The hardness ranges should be chosen, when possible, to replicate the hardness levels most commonly tested when using the specific test forces.
一<250 HV
一400HVto600HV
一>700 HV
One of the reference indentations from the current calibration period on each reference block shall be measured. For each indentation, the difference between the mean measured value and the certified mean diagonal length shall not exceed greater than 0,001 mm or 1,25 % of the reference indentation length. If preferred, this check may instead be made on a similarly-sized indentation in a different reference block with similar hardness.BS EN ISO 6507-2 pdf download.
