ASTM B721-91(1999)

1.1 This test method covers determination of the microhardness of powder metallurgy (P/M) parts and applications of microhardness test results to methods for determination of the case depth. Technique for measurement of case depth of P/M parts by observation is also outlined.

1.2 Part A: Microhardness Measurement-This procedure covers test methods to determine the microhardness of P/M parts with the Knoop (HK) or the Vickers (HV) indenters. Procedures for surface preparation of the P/M material prior to microhardness measurement are included.

1.3 Part B: Case Depth Measurement-Procedures and methods for determination of both effective case depth and observed case depth for P/M parts are included. The principles of Part A on Microhardness Measurement are utilized to measure case depth.

1.4 The values stated in inch-pound units are to be regarded as the standard. The values in parentheses are for information only.

1.5 This standard does not purport to address the safety problems 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.