ISO 6507-3:2018 pdf download – Metallic materials — Vickers hardness test — Part 3: Calibration of reference blocks.
3? Terms and definitions No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia.org/ — ISO Online browsing platform: available at http://www.iso.org/obp 4 Manufacture of reference blocks 4.1 General The block shall be specially manufactured for use as a hardness-reference block using a manufacturing process that will give the necessary homogeneity, stability of structure, uniformity of surface hardness and time-dependent stability in hardness. 4.2 Thickness The thickness of the reference block shall not be less than 5 mm. 4.3 Test surface area The test surface area of the reference block shall not exceed 40 cm 2
4.4 Magnetism The reference blocks shall be free of magnetism. It is recommended that the manufacturer shall ensure that the blocks, if made of steel, have been demagnetized at the end of the manufacturing process (before calibration). 4.5 Flatness and parallelism The maximum deviation in flatness of the test and support surfaces shall not exceed 0,005 mm. The maximum error in parallelism shall not exceed 0,010 mm in 50 mm. 4.6 Surface roughness The test surface shall be free from scratches that interfere with the measurement of the indentations. The test surface roughness, R a , shall not exceed 0,05 µm. [1] The bottom support surface shall be a finely ground finish or better. 4.7 Prevention of the regrind of the test surface To verify that no material has been subsequently removed from the reference block, its thickness at the time of calibration shall be marked on the reference block to the nearest 0,01 mm or an identifying mark shall be made on the test surface [see Clause 9 e)]. 5 Calibration machine 5.1 General In addition to fulfilling the general requirements specified in ISO 6507-2, the calibration machine shall also meet the requirements given in 5.2 to 5.6. NOTE The criteria specified in this document for the performance of the calibration machine have been developed and refined over a significant period of time. When determining a specific tolerance that the machine needs to meet, the uncertainty associated with the use of measuring equipment and/or reference standards has been incorporated within this tolerance and it would therefore be inappropriate to make any further allowance for this uncertainty by, for example, reducing the tolerance by the measurement uncertainty. This applies to all measurements made when performing a direct verification of the calibration machine.