ASTM D531-15(2019)

3.1 The Pusey and Jones indentation value is the depth of indentation, expressed in hundredths of a millimetre, of a ball 3.175 mm (0.1250 in.) in diameter under an expressed force of 9.8 N (2.2 lbf). This value may be used to compare the indentation resistance of rubber and rubber-like materials.

3.2 The indentation value obtained should not be confused with hardness as measured by Test Method D1415, since in the latter test the rubber immediately adjacent to the indentor is precompressed.

1.1 This test method covers the determination of the indentation of rubber or rubber-like materials by means of the Pusey and Jones type of plastometer. This apparatus is used to measure the depth of indentation of an indentor, under fixed force into the surface of a specimen.

1.2 The values stated in SI units are to be regarded as the standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.