ISO 6507-3 pdf download – Metallic materials – Vickers hardness test – – Part 3: Calibration of reference blocks

ISO 6507-3 pdf download – Metallic materials – Vickers hardness test – – Part 3: Calibration of reference blocks.
3.6 To verify that no matenal has been subsequently removed from the refeence block, its thickness at the time of calibration shall be marked on it. to the nearest 001 mm, or an identifying mark shall be made on the test surface (see 8.1 e)}.
4 Calibration machine
4.1 In addition to fulfilling the general requirements specified in ISO 6507-2. the calibration machine shall
also meet the requirements of 4.2 to 4.7.
4.2 The calibration machine shall be verified direcity at intervals not exceeding 12 months.
Dwect verification involves
a) verification of the test force.
b) verification of the indenter:
C) verification of the measuring device.
d) verification of the testing cycle: It this is not possible, at least the force versus time behaviour,
4.3 The mstruments used for venfication and calibration shall be traceable to national standards
4.4 Each test force shall be measured using an elastic proving device (or ISO 376:2004, Class 0.5 or bettor), or by another method having the same or bettor accuracy. This measurement shall agree with the nominal value to within t 0,1 % for normal and low-force hardness, and to within ± 0,5 % for microhardness,
4.5 The indenter shall meet the following requirements:
a) The four faces of the square-based diamond pyramid shall be highly polished, free from surface defects, and flat within 0.0003 mm.
b) The angle between the opposite faces of the vertex of the diamond pyramid shall be 136 ± 0,1.
The angle between the axis of the diamond pyramid and the axis of the indenter-holder (normal to the seating surface) shall be less than 0,3°
c) The point of the diamond indenter shall be examined with a high-power measuring microecope or preferably with an witerferonce microscope and, if the four faces do not meet at a point, the line of junction between opposite faces shall comply with the values In Table 1.
The nelrological chain necessary to define and disseminate hardness scales is shown in Figure D.1 in
ISO 6507-1:2005.
A.1 Direct verification of the hardness-calibration machine
A.1.1 Calibration of the test force
See ISO 6507-2:2005. Annex C.
A.1 .2 CalibratIon of the optical measuring device
See ISO 6507-2:2005. Annex C
kl.3 Verification of the Indenter
See 150 6507-2:2005. Annex C
Al .4 Verification of the test cycle
See ISO 6507-2:2005. Annex C.
A.2 Indirect calibration of the hardness-calibration machine
NOTE In this Annex, the rdex CRM (Ceiiifled Reference Matenal)’ means, according to the definhons at the hardness testing standards, Hardness Reference Block”
By the indirect verification with pnmary hardness-reference blocks, the overall function of the hardness calibration machine is checked and the repeatability, as well as the deviation of the hardness-calibration machine from the actual hardness value, are determined
The uncertainty of measurement of the indirect calibration of the twdness-cahbration machine follows from the equation.: