Standard Practice for Ultrasonic Surface Testing Using Electromagnetic Acoustic Transducer (EMAT) Techniques

SIGNIFICANCE AND USE
EMAT techniques show benefits and advantages over conventional piezoelectric ultrasonic techniques in special applications where flexibility in the type of wave mode generation is desired. EMATs are highly efficient in the generation of surface waves.
Since EMATs are highly efficient in the generation of surface waves, and since acoustic techniques utilizing surface waves are proven effective for detecting surface and near-surface discontinuities, they should be considered for any applications where conventional penetrant testing and magnetic particle NDT techniques are effective but undesirable.
Since EMAT techniques are non-contacting, they should be considered for ultrasonic testing where applications involve automation, high-speed inspections, moving objects, applications in remote or hazardous locations, applications to objects at elevated temperatures, or objects with rough surfaces.
The purpose of this practice is to promote the EMAT technique of the ultrasonic method as a viable alternative to conventional PT and MPT methods for detecting the presence of surface and near-surface material discontinuities.
The use of EMATs and the selection of appropriate operating parameters presuppose a knowledge of the geometry of the component; the probable location, size, orientation, and reflectivity of the expected flaws; the allowable range of EMAT lift-off; and the laws of physics governing the propagation of ultrasonic waves. This procedure pertains to a specific EMAT surface inspection application.
SCOPE
1.1 This practice covers guidelines for utilizing EMAT techniques for detecting material discontinuities that are primarily open to the surface (for example, cracks, seams, laps, cold shuts, laminations, through leaks, lack of fusion). This technique can also be sensitive to flaws and discontinuities that are not surface-breaking, provided their proximity to the surface is less than or equal to the Rayleigh wave length.
1.2 This practice covers procedures for the non-contact coupling of surface waves into a material via electromagnetic fields.
1.3 The procedures of this practice are applicable to any material in which acoustic waves can be introduced electromagnetically. This includes any material that is either electrically conductive or ferromagnetic, or both.
1.4 This practice is intended to provide examination capabilities for in-process, final, and maintenance applications.
1.5 This practice does not provide standards for the evaluation of derived indications. Interpretation, classification, and ultimate evaluation of indications, albeit necessary, are beyond the scope of this practice. Separate specifications or agreement will be necessary to define the type, size, location, and direction of indications considered acceptable or non-acceptable.
1.6 The values stated in inch-pound units are to be regarded as the standards. The SI units given in parentheses are for information only.
1.7 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.

General Information

Status
Historical
Publication Date
31-May-2009
Technical Committee
Drafting Committee
Current Stage
Ref Project

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Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E1962 −09
StandardPractice for
Ultrasonic Surface Testing Using Electromagnetic Acoustic
1
Transducer (EMAT) Techniques
This standard is issued under the fixed designation E1962; 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.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This practice covers guidelines for utilizing EMAT
E543 Specification for Agencies Performing Nondestructive
techniques for detecting material discontinuities that are pri-
Testing
marily open to the surface (for example, cracks, seams, laps,
E587 Practice for Ultrasonic Angle-Beam Contact Testing
cold shuts, laminations, through leaks, lack of fusion). This
E1316 Terminology for Nondestructive Examinations
technique can also be sensitive to flaws and discontinuities that
E1774 Guide for Electromagnetic Acoustic Transducers
are not surface-breaking, provided their proximity to the
(EMATs)
surface is less than or equal to the Rayleigh wave length.
E1816 Practice for Ultrasonic Testing Using Electromag-
1.2 This practice covers procedures for the non-contact
netic Acoustic Transducer (EMAT) Techniques
coupling of surface waves into a material via electromagnetic
2.2 ANSI/ASNT Standards:
fields.
Recommended Practice SNT-TC-1A Personnel Qualifica-
3
1.3 The procedures of this practice are applicable to any
tion and Certification in Nondestructive Testing
material in which acoustic waves can be introduced electro- ANSI/ASNT CP-189 Standard for Qualification and Certifi-
3
magnetically. This includes any material that is either electri-
cation of Nondestructive Testing Personnel
cally conductive or ferromagnetic, or both.
2.3 Military Standard:
MIL-STD-410 Nondestructive Testing Personnel Qualifica-
1.4 This practice is intended to provide examination capa-
4
tion and Certification
bilities for in-process, final, and maintenance applications.
1.5 This practice does not provide standards for the evalu-
3. Terminology
ation of derived indications. Interpretation, classification, and
3.1 Definitions:
ultimate evaluation of indications, albeit necessary, are beyond
3.1.1 Additional related terminology is defined inTerminol-
the scope of this practice. Separate specifications or agreement
ogy E1316.
will be necessary to define the type, size, location, and
direction of indications considered acceptable or non-
3.2 Definitions of Terms Specific to This Standard:
acceptable.
3.2.1 electromagnetic acoustic transducer (EMAT)—an
electromagnetic device for converting electrical energy into
1.6 The values stated in inch-pound units are to be regarded
acoustical energy in the presence of a magnetic field.
as the standards. The SI units given in parentheses are for
3.2.2 Lorentz forces—applied to electric currents when
information only.
placed in a magnetic field. Lorentz forces are perpendicular to
1.7 This standard does not purport to address all of the
both the direction of the magnetic field and the current
safety concerns, if any, associated with its use. It is the
direction. Lorentz forces are the forces responsible behind the
responsibility of the user of this standard to establish appro-
principle of electric motors.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- Standards volume information, refer to the standard’s Document Summary page on
structive Testing and is the direct responsibility of Subcommittee E07.06 on the ASTM website.
3
Ultrasonic Method. Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
CurrenteditionapprovedJune1,2009.PublishedJuly2009.Originallyapproved 4th Floor, New York, NY 10036, http://www.ansi.org.
4
in 1998. Last previous edition approved in 2004 as E1962 - 04. DOI: 10.1520/ AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
E1962-09. 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E1962−09
3.2.3 magnetostrictive forces—forces arising from magnetic
domain wall movements within a magnetic material during
magnetization.
3.2.4 meander coil—an EMAT coil consisting of periodic,
winding, non-intersecting, and usually evenly-spaced conduc-
FIG. 2Typical EMAT Meander Coil for Generation of Surface
tors.
Waves
4
...

This document is not anASTM standard and is intended only to provide the user of anASTM 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:E1962–04
Standard Test Method for Ultrasonic Surface Examinations
Using Electromagnetic Acoustic Transducer (EMAT)
TechniquesDesignation: E 1962 – 09
Standard Practice for
Ultrasonic Surface Testing Using Electromagnetic Acoustic
1
Transducer (EMAT) Techniques
This standard is issued under the fixed designation E 1962; 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.
1. Scope
1.1 This test method practice covers guidelines for utilizing EMAT techniques for detecting material discontinuities that are
primarily open to the surface (for example, cracks, seams, laps, cold shuts, laminations, through leaks, lack of fusion). This
technique can also be sensitive to flaws and discontinuities that are not surface-breaking, provided their proximity to the surface
is less than or equal to the Rayleigh wave length.
1.2 This test method practice covers procedures for the non-contact coupling of surface waves into a material via
electromagnetic fields.
1.3 The procedures of this test method practice are applicable to any material in which acoustic waves can be introduced
electromagnetically. This includes any material that is either electrically conductive or ferromagnetic, or both.
1.4 This test method practice is intended to provide examination capabilities for in-process, final, and maintenance applications.
1.5 This test method practice does not provide standards for the evaluation of derived indications. Interpretation, classification,
and ultimate evaluation of indications, albeit necessary, are beyond the scope of this test method.practice. Separate specifications
or agreement will be necessary to define the type, size, location, and direction of indications considered acceptable or
non-acceptable.
1.6 The values stated in inch-pound units are to be regarded as the standards. The SI units given in parentheses are for
information only.
1.7 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.
2. Referenced Documents
2
2.1 ASTM Standards:
E 543 Practice for Agencies Performing Nondestructive Testing
E587Specification for Agencies Performing Nondestructive Testing
E 587 Practice for Ultrasonic Angle-Beam Examination by the Contact Method
E1316
E 1316 Terminology for Nondestructive Examinations
E 1774 Guide tofor Electromagnetic Acoustic Transducers (EMATs)
E 1816 Practice for Ultrasonic ExaminationsTesting Using Electromagnetic Acoustic Transducer (EMAT) Techniques
2.2 ANSI/ASNT Standards:
1
This test method 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 MayJune 1, 2004.2009. Published May 2004.July 2009. Originally approved in 1998. Last previous edition approved in 19982004 as
E1962-98.E 1962 - 04.
2
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
E1962–09
3
Recommended Practice SNT-TC-1A Personnel Qualification and Certification in Nondestructive Testing
3
ANSI/ASNT CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel
2.3 Military Standard:
4
MIL-STD-410 Nondestructive Testing Personnel Qualification and Certification
3. Terminology
3.1 Definitions:
3.1.1 Additional related terminology is defined in Terminology E 1316.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 electromagnetic acoustic transducer (EMAT)— an electromagnetic device for converting electrical energy into acoustical
energy in the presence of a magnetic field.
3.2.2 Lorentz forces—applied to electric currents when placed in a magnetic field. Lorentz forces are perpendicular to both the
direction of the magnetic field and the current direction. Lorentz forces are the forces responsible behind the principle of e
...

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