APMP.M.H-S3 Final Report Comparison on Hardness ... - BIPM

Revision: <strong>Final</strong> <strong>Report</strong>
Date: May 25, 2012
Abstract
The <strong>APMP</strong>.M.H-<strong>S3</strong> Rockwell hardness intercomparison was initiated by NIMT,
Thailand and the required protocol was prepared by NIMT and was checked by Dr.John
Man, MNIA, Australia in 2009. In this comparison, PTB, Germany, Standards and
Calibration Laboratory (SCL), Hong Kong, National Physical Laboratory (NPLI), India,
and Korea Research Institute of Standards and Science (KRISS), Korea have
participated. This comparison exercise was focused in the measurement range of 25-100
HRBW scale and 35-85 HRA scale. The Round Robin test was done during the period
of April 2010 to October 2010. The participated NMIs have demonstrated the capability
of the machine and the operating conditions according to ISO 6508 Part3 to perform the
measurements. However, SCL, Hong Kong could demonstrate their capability to
perform the measurements only according to ISO 6508 part2. The CMC declared by the
different laboratories lie in the range of 0.30 HRA to 0.40 HRA and 0.40 HRBW to
0.75 HRBW. The CMC declared by SCL for the Rockwell B scale is 1.5HRBW due to
the reason described above. It is observed from the results that the measurement
uncertainty is estimated not less than the CMC declared by the laboratories. From the
measurement results provided by all the participated laboratories, the En ratio was
determined to establish the degree of equivalence. The En ratio was calculated by
including as well as by excluding the results of the laboratory which has performed the
test according to ISO 6508 Part2 in order to make sure that it does not affect the overall
results. It is noticed that the En ratio still found to remain less than 1.
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