ISO 6506-2:2014 pdf free
ISO 6506-2:2014 pdf free.Metallic materials – Brinell hardness test – Verification and calibration of testing machines
For systems where the indentation diameter is measured directly, the scale of the system shall be graduated to permit estimation of the diameter to within +0,5 %. The indentation diameter measuring system shall be calibrated for every objective lens, and for each incorporated line scale, in two perpendicular measurement axes (if applicable), by measurements made on a standard scale at a minimum of four intervals, arranged centrally in the field of view, for each working range. For each measurement, the magnitude of the difference between the measured and reference values shall not be greater than 0,5 % (see Formula A.7).
For systems where the indentation diameter is calculated from a measurement of projected area,the system shall be calibrated for every objective lens by measurements of a range of at least four standard circular reference images covering the range of areas measured. The maximum error shall not exceed 1 % of the area.
All systems shall also be verified by making measurements of certified reference indentations,such as those on hardness reference blocks calibrated in accordance with ISO 6506-3. For each ball size, at least four indentations, covering the working range of diameters, shall be measured by each objective lens. During these measurements, the type of illumination shall remain unchanged. No mean measured diameter shall differ from the certified mean diameter of the reference indentation by more than 0,5 %.
The testing cycle is to be verified by the testing machine manufacturer at the time of manufacture and when the testing machine undergoes repair which might have affected the testing cycle. Verification of the testing cycle at other times is as specified in Table 4.
The testing cycle shall be verified to conform with the testing cycle defined in ISO 6506- 1, taking into account any uncertainty associated with the timing measurements.ISO 6506-2 pdf free download.
