BS EN ISO 4545-3:2015 pdf download

BS EN ISO 4545-3:2015 pdf download.Draft BS EN ISO 4545-3 Metallic materials – Knoop hardness test Part 3: Calibration of reference blocks.
3.7 To verify that no material is subsequently removed from the reference block, the thickness at the time of calibration shall be marked on it, to the nearest 0.1 mm, or an identifying mark shall be made on the test surface Lsee 8.1.e)J.
4 Calibration machine
4.1 In addition to fulfilling the general requirements specified in ISO 4545-2, the calibration machine shall also meet the requirements given in 4.2 to 47.
NOTE Examples of procedures for adjustment of illumination systems are given in Annex A.
4.2 The mactune shall have been directly verified in intervals not exceeding 12 months
Direct verification involves:
a) calibration of the test force;
b) verification of the indenter;
C) calibration and verification of the diagonal measuring system;
d) verification of the testing cycle.
4.3 The instruments used for verification and calibration shall be traceable to national standards,
4.4 Each test force shall b€ verified at 3 different positions of the plunger, spaced at approximately equal increments covering the limits of travel used during testing. Al each position, the force shal be measured three times using an elastic proving device according to ISO 376 Class 0.5 or better, or by another method having the same or better accuracy. Each measurement shall agree with the nominal value to within ±0,5 %.
4.5 The indenter shall comply with ISO 4545-2 clause 4.3 arid meet the following requirements:
a) The angle 8 (see ISO 4545-1, Figure 1). between opposite edges at the vertex of the diamond pyramid. shall be (130± 0,1).
b) The angle between the axis of the diamond pyramid arid the axis of the indenter holder (normal to the seating surface) shall not exceed 0,3. The four faces shall meet at a point; the length of any common jwiction between opposite faces being less than 0,000 3mm.
4.6 The diagonal measuring system shall be verIfied at a minimum of frye evenly spaced Intervals over each working range against an accurately ruled stage micrometer The accuracy of the line intervals on the stage micrometer shall be 0.0001 mm or 0,05 %. whichever is greater.
The maximum permissible error of the diagonal measuring system at each interval shall be ± 0,0002 mm or 0.25 % whichever is greater
4.7 The maximum allowable vibrational acceleration reaching the machine shall be less than O.OO5g (g being the acceleration due to gravity (g – 9806 65 rn/s2)]
5 Calibration procedure
The reference blocks shall be calibrated in a calibration machine as specified in Clause 4, at a temperature of (23 ± 5) C, using the general procedure described in ISO 4545-1.
During calibration, the thermal drift should not exceed 1 C.
8.3 Each delivered reference block shall be accompanied with a document giving at least the following information:
a) a reference to this part of ISO 4545;
b) the identity of the block;
c) the date of calibration;
d) Ihe test force used to perform the calibration;
e) the arithmetic mean of the hardness values in the format defined ii ISO 4545-1. 4.2, and the value characterizing the non-uniformity & the block;
f) information about the location of each reference indentation together with the length of the long diagonal.
9 Validity
The reference block is only valid for the scale for which It was calibrated.
The calibration vabdity should be linited to a duration of 5 years. Attention is drawn to the fact that, for Al- end Cu-alloys, the calibration validity could be reduced to 2-3 years.
Marking
Each reference block shall be marked with the following particulars:
arithmetic mean of the hardness values found in the calibration test, for example 249 HK 1, if possible; name or mark of the supplier or manufacturer; serial number; name or mark of the calibrating agency; thickness of the block, or an identifying mark on the test surface (see 3.7); year of calibration, If not indicated in the senal number.
My mark put on the side of the block shall be the right way up when the test surface is the upper face.