ASTM D785-08(2015)

4.3 For certain types of materials having creep and recovery, the time factors involved in applications of major and minor loads have a considerable effect on the results of the measurements.

4.4 The results obtained by this test method are not generally considered a measure of the abrasion or wear resistance of the plastic materials in question.

4.5 Indentation hardness is used as an indication of cure of some thermosetting materials at room temperature. Generally, an uncured specimen has a hardness reading below normal.

4.6 Each Rockwell hardness scale in Table 1 is an extension of the proceeding less severe scale, and while there is some overlap between adjacent scales, a correlation table is not desirable. Readings on one material may be satisfactory for such a table, but there is no guarantee that other plastic materials will give corresponding readings because of differences in elasticity, creep, and shear characteristics.

1.1 This test method covers two procedures for testing the indention hardness of plastics and related plastic electrical insulating materials by means of the Rockwell hardness tester.

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