ASTM E494-20
(Practice)Standard Practice for Measuring Ultrasonic Velocity in Materials by Comparative Pulse-Echo Method
Standard Practice for Measuring Ultrasonic Velocity in Materials by Comparative Pulse-Echo Method
ABSTRACT
This practice covers a test procedure for measuring ultrasonic velocities in materials with conventional ultrasonic pulse echo flaw detection equipment in which results are displayed in an A-scan display, and describes a method whereby unknown ultrasonic velocities in a material sample are determined by comparative measurements using a reference material whose ultrasonic velocities are accurately known. The ultrasonic testing system that shall be used shall consist of the test instrument, search unit, couplant, and the standard reference blocks. The test procedure shall include both longitudinal and transverse wave velocity measurements, which should conform to the theoretical values of the parameters.
SIGNIFICANCE AND USE
5.1 This practice describes a test procedure for the application of conventional ultrasonic methods to determine unknown ultrasonic velocities in a material sample by comparative measurements using a reference material whose ultrasonic velocities are accurately known.
5.2 Although not all methods described in this practice are applied equally or universally to all velocity measurements in different materials, it does provide flexibility and a basis for establishing contractual criteria between users, and may be used as a general guideline for preparing a detailed procedure or specification for a particular application.
5.3 This practice is directed towards the determination of longitudinal and shear wave velocities using the appropriate sound wave form. This practice also outlines methods to determine elastic modulus and can be applied in both contact and immersion mode.
SCOPE
1.1 This practice covers a test procedure for measuring ultrasonic velocities in materials with conventional ultrasonic pulse echo flaw detection equipment in which results are displayed in an A-scan display. This practice describes a method whereby unknown ultrasonic velocities in a material sample are determined by comparative measurements using a reference material whose ultrasonic velocities are accurately known.
1.2 This procedure is intended for solid materials 5 mm (0.2 in.) thick or greater. The surfaces normal to the direction of energy propagation shall be parallel to at least ±3°. Surface finish for velocity measurements shall be 3.2 μm (125 μin.) root-mean-square (rms) or smoother.
Note 1: Sound wave velocities are cited in this practice using the fundamental units of meters per second, with inches per second supplied for reference in many cases. For some calculations, it is convenient to think of velocities in units of millimeters per microsecond. While these units work nicely in the calculations, the more natural units were chosen for use in the tables in this practice. The values can be simply converted from m/s to mm/μs by moving the decimal point three places to the left, that is, 3500 m/s becomes 3.5 mm/μs.
1.3 Ultrasonic velocity measurements are useful for determining several important material properties. Young's modulus of elasticity, Poisson's ratio, acoustic impedance, and several other useful properties and coefficients can be calculated for solid materials with the ultrasonic velocities if the density is known (see Appendix X1).
1.4 More accurate results than those obtained using this method can be obtained with more specialized ultrasonic equipment, auxiliary equipment, and specialized techniques. Some of the supplemental techniques are described in Appendix X2. (Material contained in Appendix X2 is for informational purposes only.)
Note 2: Factors including techniques, equipment, types of material, and operator variables will result in variations in absolute velocity readings, sometimes by as much as ±5 %. Relative results with a single combination of the above factors can be expected to be much more accurate (probably within a 1 % tolerance).
1.5 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI uni...
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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.
Designation: E494 − 20
Standard Practice for
Measuring Ultrasonic Velocity in Materials by Comparative
1
Pulse-Echo Method
This standard is issued under the fixed designation E494; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
NOTE 2—Factors including techniques, equipment, types of material,
1. Scope*
and operator variables will result in variations in absolute velocity
1.1 This practice covers a test procedure for measuring
readings, sometimes by as much as 65%. Relative results with a single
ultrasonic velocities in materials with conventional ultrasonic combination of the above factors can be expected to be much more
accurate (probably within a 1% tolerance).
pulse echo flaw detection equipment in which results are
displayed in an A-scan display. This practice describes a
1.5 Units—The values stated in SI units are to be regarded
method whereby unknown ultrasonic velocities in a material
as standard. The values given in parentheses after SI units are
sample are determined by comparative measurements using a
providedforinformationonlyandarenotconsideredstandard.
reference material whose ultrasonic velocities are accurately
1.6 This standard does not purport to address all of the
known.
safety concerns, if any, associated with its use. It is the
1.2 This procedure is intended for solid materials 5 mm
responsibility of the user of this standard to establish appro-
(0.2in.) thick or greater. The surfaces normal to the direction priate safety, health, and environmental practices and deter-
of energy propagation shall be parallel to at least 63°. Surface
mine the applicability of regulatory limitations prior to use.
finish for velocity measurements shall be 3.2 µm (125 µin.) 1.7 This international standard was developed in accor-
root-mean-square (rms) or smoother.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
NOTE 1—Sound wave velocities are cited in this practice using the
Development of International Standards, Guides and Recom-
fundamental units of meters per second, with inches per second supplied
mendations issued by the World Trade Organization Technical
for reference in many cases. For some calculations, it is convenient to
think of velocities in units of millimeters per microsecond. While these
Barriers to Trade (TBT) Committee.
units work nicely in the calculations, the more natural units were chosen
for use in the tables in this practice. The values can be simply converted
2. Referenced Documents
from m/s to mm/µs by moving the decimal point three places to the left,
2
that is, 3500 m/s becomes 3.5 mm/µs.
2.1 ASTM Standards:
1.3 Ultrasonic velocity measurements are useful for deter- C597Test Method for Pulse Velocity Through Concrete
E317PracticeforEvaluatingPerformanceCharacteristicsof
miningseveralimportantmaterialproperties.Young’smodulus
Ultrasonic Pulse-Echo Testing Instruments and Systems
of elasticity, Poisson’s ratio, acoustic impedance, and several
without the Use of Electronic Measurement Instruments
other useful properties and coefficients can be calculated for
E543Specification forAgencies Performing Nondestructive
solid materials with the ultrasonic velocities if the density is
Testing
known (see Appendix X1).
E797Practice for Measuring Thickness by Manual Ultra-
1.4 More accurate results than those obtained using this
sonic Pulse-Echo Contact Method
method can be obtained with more specialized ultrasonic
E1316Terminology for Nondestructive Examinations
equipment, auxiliary equipment, and specialized techniques.
3
2.2 ASNT Documents:
Some of the supplemental techniques are described in Appen-
SNT-TC-1A Recommended Practice for Nondestructive
dix X2. (Material contained in Appendix X2 is for informa-
Testing Personnel Qualification and Certification
tional purposes only.)
1 2
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- For referenced ASTM standards, visit the ASTM website, www.astm.org, or
structive Testing and is the direct responsibility of Subcommittee E07.06 on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Ultrasonic Method. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 1, 2020. Published January 2021. Originally the ASTM website.
3
approved in 1973.
...
This document is not 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. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E494 − 15 E494 − 20
Standard Practice for
Measuring Ultrasonic Velocity in Materials by Comparative
1
Pulse-Echo Method
This standard is issued under the fixed designation E494; the number immediately following the designation indicates the year of
original adoption 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 This practice covers a test procedure for measuring ultrasonic velocities in materials with conventional ultrasonic pulse echo
flaw detection equipment in which results are displayed in an A-scan display. This practice describes a method whereby unknown
ultrasonic velocities in a material sample are determined by comparative measurements using a reference material whose ultrasonic
velocities are accurately known.
1.2 This procedure is intended for solid materials 5 mm (0.2 in.) thick or greater. The surfaces normal to the direction of energy
propagation shall be parallel to at least 63°. Surface finish for velocity measurements shall be 3.2 μm (125 μin.) root-mean-square
(rms) or smoother.
NOTE 1—Sound wave velocities are cited in this practice using the fundamental units of metresmeters per second, with inches per second supplied for
reference in many cases. For some calculations, it is convenient to think of velocities in units of millimetresmillimeters per microsecond. While these
units work nicely in the calculations, the more natural units were chosen for use in the tables in this practice. The values can be simply converted from
m/s to mm/μs by moving the decimal point three places to the left, that is, 3500 m/s becomes 3.5 mm/μs.
1.3 Ultrasonic velocity measurements are useful for determining several important material properties. Young’s modulus of
elasticity, Poisson’s ratio, acoustic impedance, and several other useful properties and coefficients can be calculated for solid
materials with the ultrasonic velocities if the density is known (see Appendix X1).
1.4 More accurate results than those obtained using this method can be obtained with more specialized ultrasonic equipment,
auxiliary equipment, and specialized techniques. Some of the supplemental techniques are described in Appendix X2. (Material
contained in Appendix X2 is for informational purposes only.)
NOTE 2—Factors including techniques, equipment, types of material, and operator variables will result in variations in absolute velocity readings,
sometimes by as much as 5 %.65 %. Relative results with a single combination of the above factors can be expected to be much more accurate (probably
within a 1 % tolerance).
1.5 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided
for information only and are not considered 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1
This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.06 on Ultrasonic Method.
Current edition approved Dec. 1, 2015Dec. 1, 2020. Published December 2015January 2021. Originally approved in 1973. Last previous edition approved in 20102015
as E494 - 10.E494 – 15. DOI: 10.1520/E0494-15.10.1520/E0494-20.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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E494 − 20
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.
2. Referenced Documents
2
2.1 ASTM Standards:
C597 Test Method for Pulse Velocity Through Concrete
E317 Practice for Evaluating Performance Characteristics of Ultrasonic Pulse-Echo Testing Instruments and Systems without the
Use of Electronic Measurement Instruments
E543 S
...
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