ASTM D1415-2018 pdf free download
ASTM D1415-2018 pdf free download.Standard Test Method for Rubber Property—International Hardness
1. Scope
1.1 This test method covers a procedure for measuring the hardness of vulcanized or thermoplastic rubber. The hardness is obtained by the difference in penetration depth of a specified dimension ball under two conditions of contact with the rubber: (I) with a small initial force and (2) with a much larger final force. The differential penetration is taken at a specified time and converted to a hardness scale value. 1.2 This test method is technically similar to ISO 48. 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 of regulatory 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.
4. Significance and Use
4.1 The International Hardness test is based on measure- ment of the penetration of a rigid ball into the rubber specimen under specified conditions. The measured penetration is con- verted into IRHD, the scale of degrees being so chosen that 0 represents a material having an elastic modulus of zero, and 100 represents a material of infinite elastic modulus. 4.1.1 The scale also fulfills the following conditions over most of the normal range of hardness: one IRHD range represents approximately the same proportionate difference in Young’s modulus， and for rubber vulcanizates in the usual range of resilience， readings in IRHD are comparable with those given by a Type A durometer (Test Method D2240) when testing standard specimens. 4.1.1.1 The term “usual range of resilience” is used to exclude those compounds that have unusually high rates of stress relaxation or deformational hysteresis. For such compounds, differences in the dwell time in the two hardness tests (Test Methods D2240 and D1415) result in differences in hardness values. Readings may not be comparable when testing curved or irregularly shaped test specimens. 4.1.2 For substantially elastic isotropic materials like well- vulcanized natural rubbers， the hardness in IRHD bears a known relation to Young’s modulus， although for markedly plastic or anisotropic rubbers the relationship will be less precisely known. 4.1.3 The relation between the difference of penetration and the hardness expressed in IRHD is based on the following.
5. Apparatus
5.1 The essential parts of the apparatus are as follows, the appropriate dimensions and loads being given in Table 1: 5.1.1 Vertical Plunger, terminating in a rigid ball. 5.1.2 Force Applicator, for applying a minor force and a major force to the ball, the mass of the plunger, and of any fittings attached to it, and the force of any spring acting on it shall be included in determining the minor and major forces. This is in order that the forces actually applied to the ball shall be as specified. 5.1.3 Measuring Device—A mechanical, optical, or electri- cal device graduated either in standard units of length or in IRHD for measuring the increase in depth of penetration of the plunger caused by the major load. 5.1.4 Foot—A flat annular-shaped foot that is rigidly fas- tened to the penetration-measuring device and normal to the axis of the plunger, and which during the test is forced against the specimen in order to determine accurately the position of the upper surface.
