ASTM B390-92(2006) PDF

1.1 This practice for the visual comparison and classification of the apparent grain size and distribution of cemented tungsten carbides is limited to cemented tungsten carbides that contain approximately 6, 10, and 18 % cobalt.

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.