Pellet hardness is related to several carbon black characteristics. Among these are mass strength and attrition. The subsequent level of dispersion obtained in some mixed compounds containing the carbon black may be affected by pellet hardness. Acceptable pellet hardness must be agreed to by the user and the producer.

Note 1—Test Method D 5230 is the preferred standard for testing of individual pellet hardness. It is recognized that Test Method D 3313 relies on operator judgement, thus adding an additional source of variation for this test.

1.1 This test method covers a method for measuring the hardness of individual pellets of carbon black.

1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

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 and health practices and determine the applicability of regulatory limitations prior to use.