ASTM E2985_E2985M-14R19 - Standard Practice for Determination of Metal Purity Based on Elastic Constant Measurements Derived from Resonant Ultrasound Spectroscopy

1.1 This practice is intended for use with resonant ultrasound spectrometers capable of exciting, measuring, recording, and analyzing multiple whole body mechanical vibration resonant frequencies within parts exhibiting acoustical ringing in the acoustic or ultrasonic, or both, resonant frequency ranges.

1.2 This practice uses Resonant Ultrasound Spectroscopy (RUS) to distinguish conforming parts, as determined from qualified training sets, from those containing significant anomalies in their elastic properties.

1.3 The basic functions of a RUS monitoring system are to detect and classify resonance phenomena. Solid structure resonances are governed by the part’s dimensions, density, and elastic properties. When a material substitution occurs in a precious metal, the chosen metals have almost identical densities and unchanged dimensions, leaving only the elastic properties to affect the resonances.

1.4 This practice can be used to replace destructive methods, which damage the test object through drilling or melting, or both.

1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

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

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.