ASTM D531-15(R2019) pdf free download

ASTM D531-15(R2019) pdf free download.Standard Test Method for Rubber Property—Pusey and Jones Indentation
1. Scope
1.1 This test method covers the determination of the inden- tation 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Significance and Use
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.
4. Apparatus
4.1 Plastometer, an instrument consisting of an indentor, a mass for applying the stated force on the indentor, a microm- eter for indicating the depth of the indentation, a specimen holder and support. 4.1.1 Indentor, for indenting the specimen, consisting of a vertical steel shaft attached, at the upper end to a depth indicator gage, and terminating in a steel sphere having a diameter of 3.175 6 0.015 mm (0.1250 6 0.0005 in.) of polished, noncorrosive hard metal treated to resist wear. 4.1.2 Mass, the mass shall be 1000 6 0.01 g. 4.1.3 Depth Indicator Gage, a micrometer attached to the plastometer, either an electronic digital gage or analog dial gage, capable of displaying indentor movement (indentation) in increments ofat least 0.01 mm (0.0004 in.) and having travel of 0 (zero) to no less than 3 mm (0.12 in). 4.1.4 Support, a support frame, or fixture, for the plastometer, shall be configured so that the specimen holder and hence, the specimen, are perpendicular to the indentor support shaft and that the mass may be independently raised or lowered vertically, permitting the indentor to rest on the surface of the specimen and the mass to be subsequently applied. 4.1.5 Specimen Holder, for the standard, or reference speci- men described in 5.1, shall consist of a clamping fixture of two metal plates secured by two threaded bolts. The uppermost plate shall have a hole and a slot, as depicted in Fig. 1, to allow for the unencumbered introduction of the indentor to the specimen.
6. Procedure
6.1 Measurement of Indentation of Standard, or Reference Specimens: 6.1.1 When measuring the indentation on a standard, or reference specimen as described in 5.1, secure it in the specimen holder (refer to Fig. 1 and Section 4.1.5) with the bolts tightened sufficiently to hold it firmly without measurable compression. 6.1.2 Place the specimen holder on the support. 6.1.3 Mount the plastometer over the specimen so that the indentor shaft is perpendicular to the support and hence the specimen holder, to within 60.05 mm (60.002 in). 6.1.4 The plastometer and support shall be placed upon a flat surface in a manner that prevents unsteadiness or move- ment other than described in 6.3. 6.1.5 Lower the indentor shaft until the indentor is at the moment of contact with the specimen. 6.1.5.1 Adjust the depth indicator gage to record indenta- tions up to 3 mm (0.12 in). 6.1.5.2 Adjust the depth indicator gage so the display indicates zero.