SOME PROBLEMS USING REFERENCE RUBBER BLOCKS AS A STANDARD

Anton Stibler, Febo Menelao, Konrad Herrmann

Abstract

Reference blocks can be used for the verification of hardness testers of rubber in the same way as in the case of hardness measurement of metals. When using hardness reference blocks for verification the so called indirect verification method is applied. This method is not yet part of the standard ISO 18898: Rubber, Verification and Calibration of Hardness Testers, but there is a high chance that this method will be a mandatory part of this standard in near future.<br />This paper deals with some problems when using rubber hardness blocks as a standard for the verification of hardness testers. Mechanical properties of rubber material are relatively unstable compared with those of metals but on the other hand rubber is a very deformable material and almost completely recoverable. This fact and results obtained during practical investigations lead us to the conclusion that even several indentations performed into the same point of the surface of the blocks can give us repeatable and therefore reliable hardness values. This is not the case in hardness measurement of metals where each indentation causes total destruction of the material under and around the indenter.

Keywords

rubber hardness testers, rubber hardness blocks, calibrations

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IMEKO-TC5-2010-NP-013.pdf

DOI

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IMEKO TC

TC5 - Hardness Measurement

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