ASTM E2904-12

5.1 This standard practice is intended to provide standardized procedures for evaluating linear phased-array ultrasonic probes. It is not intended to define performance and acceptance criteria, but rather to provide data from which such criteria may be established.

5.2 Implementation may require more detailed procedural instructions in a format of the using facility.

5.3 The measurement data obtained may be employed by users of this guide to specify, describe, or provide performance criteria for procurement and quality assurance, or service evaluation of the operating characteristics of linear phased-array ultrasonic probes. All or portions of the standard practice may be used as determined by the user.

5.4 The measurements are made primarily under pulse-echo conditions. To determine the relative performance of a probe element as either a transmitter or a receiver may require additional tests.

5.5 While these procedures relate to many of the significant parameters, others that may be important in specific applications may not be treated. These might include power handling capability, breakdown voltage, wear properties of contact units, radio-frequency interference, and the like.

5.6 Care must be taken to ensure that comparable measurements are made and that users of the standard practice follow similar procedures. The conditions specified or selected (if optional) may affect the test results and lead to apparent differences.

5.7 Interpretation of some test results, such as the shape of the frequency response curve, may be subjective. Small irregularities may be significant. Interpretation of the test results is beyond the scope of this standard practice.

5.8 Certain results obtained using the procedures outlined may differ from measurements made with phased-array ultrasonic test instruments. These differences may be attributed to differences in the nature of the experiment or the electrical characteristics of the instrumentation.

5.9 The pulse generator used to obtain the frequency response and time response of the probe must have a rise time, duration, and spectral content sufficient to excite the probe over its full bandwidth, otherwise time distortion and erroneous results may result.

1.1 This standard practice covers measurement procedures for evaluating certain characteristics of phased-array ultrasonic probes that are used with phased-array ultrasonic examination instrumentation.

1.2 This standard practice describes means for obtaining performance data that may be used to define the acoustic and electric responses of phased-array ultrasonic probes including contact (with or without a wedge) and immersion linear phased-array probes used for ultrasonic nondestructive testing with central frequencies ranging from 0.5 MHz to 10 MHz. Frequencies outside of this range may use the same methods but the testing equipment may vary.

1.3 When ultrasonic values dependent on material are specified in this document, they are based on carbon steel with an ultrasonic wave propagation speed of 5920 m/s (±50 m/s) for longitudinal wave modes and 3255 m/s (±30 m/s) for transverse or shear wave modes.

1.4 This document describes the characterization and verification procedures that are to be carried out at the end stage of the manufacturing process of phased array probes. This document does not describe the methods or acceptance criteria used to verify the performance of the entire phased array ultrasonic instrument and probe.

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

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