CHARACTERISTIC QUALITY PARAMETERS OF MEASUREMENT -VERIFICATION AND CALIBRATION OF MATERIAL TESTING MACHINES

Dieter Schwenk, Andreas Subaric-Leitis

Abstract

The international standards for qualification of material testing machines like the ISO standards for hardness testing [1] -[3] use the relative span (range) as a repeatability parameter. Form the view of statistics and uncertainty the determination of the range is not suitable for this purpose. We propose a transition from range to standard deviation for describing the machines quality parameter which allows a direct estimate of the machines uncertainty and of the reliability of test results within the limits fixed by the ISO standards. For the transition from range to standard deviation the limits have to be transformed. We represent results of conformity decisions determined on the basis of data sets of hardness reference block calibration with reference testing machines using the limits concerning range and the equivalent limits related to the standard deviation.

Keywords

span, standard deviation, material testing machines

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IMEKO-TC5-2010-032.pdf

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IMEKO TC

TC3 - Measurement of Force, Mass, Torque, and Gravity

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