1、Designation: E664/E664M 10E664/E664M 15Standard Practice for theMeasurement of the Apparent Attenuation of LongitudinalUltrasonic Waves by Immersion Method1This standard is issued under the fixed designation E664/E664M; the number immediately following the designation indicates the yearof original a
2、doption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This practice describes a procedure for measuring the apparent
3、 attenuation of ultrasound in materials or components withflat, parallel surfaces using conventional pulse-echo ultrasonic flaw detection equipment in which reflected indications aredisplayed in an A-scan presentation.1.2 The measurement procedure is readily adaptable for the determination of relati
4、ve attenuation between materials. Forabsolute (true) attenuation measurements, indicative of the intrinsic nature of the material, it is necessary to correct for specimengeometry, sound beam divergence, instrumentation, and procedural effects. These results can be obtained with more specializedultra
5、sonic equipment and techniques.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems m
6、ay result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regul
7、atorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E214 Practice for Immersed Ultrasonic Testing by the Reflection Method Using Pulsed Longitudinal Waves (Withdrawn 2007)3E317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-EchoTesting Instruments and Sy
8、stems without theUse of Electronic Measurement InstrumentsE543 Specification for Agencies Performing Nondestructive TestingE1316 Terminology for Nondestructive Examinations2.2 Other Documents:SNT-TC-1A Recommended for Personnel Qualification and Certification of Nondestructive Testing Personnel3ANSI
9、/ASNT CP-189 ASNT Standard for Qualification and Certification of Nondestructive Testing Personnel2NAS-410 NAS Certification and Qualification of Nondestructive Personnel (Quality Assurance Committee)4ISO 9712 Non-destructive TestingQualification and Certification of NDT Personnel53. Terminology3.1
10、DefinitionsFor definitions of terms used in this practice, see Terminology E1316.4. Summary of Practice4.1 This practice describes a procedure for determining apparent attenuation by measuring the decay of multiple back reflectionsof longitudinal ultrasonic waves introduced into specimens with flat,
11、 parallel surfaces by the immersion technique.1 This practice is under the jurisdiction ofASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.06 on Ultrasonic Method.Current edition approved June 1, 2010June 1, 2015. Published July 2010 June 2015. Origin
12、ally approved in 1978. Last previous edition approved in 20052010 asE664 - 93E664 - 10.(2005). DOI: 10.1520/E0664_E0664M-10.10.1520/E0664_E0664M-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standar
13、dsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.Available from American Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518,
14、http:/www.asnt.org.4 Available from Aerospace Industries Association of America, Inc., 1250 Eye St., NW, Washington, DC 20005.5 Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http:/www.iso.org.This document is not
15、 an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate
16、. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.
17、Significance and Use5.1 The measurement of apparent attenuation in materials is useful in applications such as the comparison of heat treatmentsof different lots of material or the assessment of the degradation of materials due to environment.5.2 Several different modes of wave vibration can be prop
18、agated in solids. This practice is concerned with the attenuationassociated with longitudinal waves introduced into the specimen by the immersion method.5.3 This practice allows for the comparison of the apparent attenuations of geometrically similar specimens.5.4 For the determination of apparent a
19、ttenuation, the procedures described herein are valid only for measurements in the farfield of the ultrasonic beam.6. Basis of Application6.1 The following items are subject to contractual agreement between the parties using or referencing this standard.6.2 Personnel Qualification6.2.1 If specified
20、in the contract agreement, personnel performing examinations to this standard shall be qualified in accordancewith a nationally or internationally recognized NDT personnel qualification practice or standard such as ANSI/ASNT-CP-189,SNT-TC-1A, NAS-410, ISO 9712 or similar document and certified by th
21、e employer or certifying agency, as applicable. Thepractice or standard used and its applicable revision shall be identified in the contractual agreement between the using parties.6.3 Qualification of Nondestructive AgenciesIf specified in the contractual agreement, NDT agencies shall be qualified a
22、ndevaluated as described in Specification E543. The applicable edition of Specification E543 shall be specified in the contractualagreement.6.4 Procedures and TechniquesThe procedures and techniques to be utilized shall be as specified in the contractual agreement.6.5 Timing of ExaminationThe timing
23、 of examination shall be identified in the contractual agreement between the usingparties.6.6 Extent of ExaminationThe extent of the examination shall be identified in the contractual agreement between the usingparties.6.7 Reporting Criteria/Acceptance CriteriaReporting criteria for the examination
24、results shall be in accordance with Section10 unless otherwise specified. Since acceptance criteria are not specified in this standard, they shall be specified in the contractualagreement.6.8 Re-examination of Repair/Reworked ItemsRe-examination of repaired/reworked items is not addressed in this st
25、andardand if required shall be specified in the contractual agreement.7. Apparatus7.1 Ultrasonic Flaw Detection System A system capable of generating, receiving, and displaying electrical pulsesultrasonicenergy at the frequency of interest. Display shall be an A-scan presentation.7.1.1 Performance C
26、haracteristicsThe vertical linearity limits shall be determined as specified in Practice E317. Allmeasurements shall be made only within the linear ranges of the system.7.2 Search UnitThe size and frequency should be determined to suit the application, and only non-focused search units maybe used.7.
27、3 CouplantNormally water. See PracticeTerminology E214E1316 for alternatives7.4 Reference BlockThe use of a reference block is suggested to evaluate the stability of the measurement system ifmeasurements will be made over a period of time. The reference block should have acoustic properties similar
28、to those of theexamined material in the frequency range of interest.8. Specimen8.1 Geometric SimilarityWhen comparing the apparent attenuations of two or more materials or components, the specimensused must be geometrically similar. They must be flat and parallel within 0.008 in. 0.20 mm/in. 25.4 mm
29、 of diameter or crosssection and differ in thickness by no more than a factor of 2. The cross section of each specimen must meet the requirements of7.28.2.8.2 Minimum DimensionsThe thickness of the specimen (parallel to the ultrasonic beam) shall be of a dimension so that atleast two back surface re
30、flections can be resolved at the frequency of interest. The dimensions normal to the ultrasonic beam shallbe much greater than the beam width and wavelength (at least three times the transducer dimension) so that side wall echoes donot interfere with the measurements.NOTE 1For the determination of t
31、rue attenuation, careful consideration must be made of parameters such as front surface and back surface parallelism,surface finish, etc. However, useful apparent attenuation information can be obtained if the requirements of 7.18.1 and 7.28.2 are satisfied.E664/E664M 1529. Procedure9.1 Measure the
32、thickness of the specimen to an accuracy of 60.001 in. 60.03 mm or 60.1 %, whichever is greater.9.2 Place the sample in a suitable immersion tank.9.3 Place the search unit in a fixture suitable for manipulating the sound entry angle and lateral position. Position the searchunit over the sample, and
33、angulate the beam to obtain the maximum number of back reflections. See Fig. 1. The water path shouldbe such that the entry surface is in the far field of the ultrasonic beam.NOTE 2If the frequency and dimensions of the transducers available do not readily permit the top surface of sample to be in t
34、he far field, this methodmay be used provided the back reflections measured and recorded are in the far field of the sound beam.9.3.1 With the reject level set at zero, measure and record the amplitudes of any two back reflections that show decreasingamplitude with increase in back reflection number
35、.NOTE 3If the apparent attenuation of two or more materials or components are to be compared, the same two back reflections should be selectedfor each sample.9.3.2 Determine the apparent attenuation by the relationship indicated below. The apparent attenuation will be in terms ofdecibels per unit le
36、ngth as defined by the units of thickness.Apparent attenuation520 log10 AmAn2n 2m! Twhere:Am andAn = amplitudes of the mth and nth back reflections (n m), andT = specimen thickness.NOTE 4When instruments are used that have dB calibrated gain control, the measurements in decibels may be used instead
37、of amplitudemeasurements. The dB control is used to bring the amplitude of the nth reflection up to the amplitude of the mth reflection and the gain in decibels issubstituted for the numerator in the attenuation formula. The formula then becomes:dB2n 2m! T10. Report10.1 The report should include the
38、 following:10.1.1 Instrument make, model, and serial number,10.1.2 Pertinent equipment settings such as gain, pulse length, damping, etc.,10.1.3 Search unit type, frequency, serial number and transducer size,10.1.4 Specimen dimensions,10.1.5 Amplitudes and numbers of each of the back reflections use
39、d to calculate the attenuation parameter,10.1.6 Attenuation parameter, and10.1.7 Water path length.FIG. 1 Typical A-Scan Presentation Showing Multiple Back Reflections for Evaluation of Apparent Attenuation.E664/E664M 15311. Keywords11.1 apparent attenuation; attenuation; immersion method; nondestru
40、ctive examination; ultrasonic examinationSUMMARY OF CHANGESCommittee E07 has identified the location of selected changes to this standard since the last issue (E664) thatmay impact the use of this standard.(1) Section 2, Reference DocumentsRemoved E214, which was withdrawn in 2007.(2) Inserted Secti
41、on 6, Basis of Application, and renumbered subsequent sections.(3) Section 7.1,ApparatusRemoved “electrical pulses” and replaced with “ultrasonic energy.” This conforms to the TerminologyE1316-14 definition under “Apparent Attenuation.”(4) Section 7.3Removed reference to E214 and referred to Termino
42、logy E1316.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such
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