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ASTM E1816-07

(Practice)

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

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

SCOPE
1.1 This practice covers procedures for the use of electromagnetic acoustic transducers (EMATs) for specific ultrasonic examination applications. Recommendations are given for specific applications for using EMAT techniques to detect flaws through both surface and volumetric examinations as well as to measure thickness.
1.2 These procedures recommend technical details and guidelines for the reliable and reproducible ultrasonic detection of flaws and thickness measurements using electromagnetic acoustic transducers for both the pulsing and receiving of ultrasonic waves. The EMAT techniques described herein can be used as a basis for assessing the serviceability of various components nondestructively, as well as for process control in manufacturing.
1.3 These procedures cover noncontact techniques for coupling ultrasonic energy into materials through the use of electromagnetic fields. Surface, Lamb, longitudinal, and shear wave modes are discussed.
1.4 These procedures are intended to describe specific EMAT applications. These procedures are intended for applications in which the user has determined that the use of EMAT techniques can offer substantial benefits over conventional piezoelectric search units. It is not intended that EMAT techniques should be used in applications in which conventional techniques and applications offer superior benefits (refer to Guide E 1774).
1.5 These procedures are applicable to any material in which acoustic waves can be introduced electromagnetically. This includes any material that is either electrically conductive or ferromagnetic.
1.6 The procedures outlined in this practice address proven EMAT techniques for specific applications; they do not purport to address the only variation or all variations of EMAT techniques to address the given applications. Latitude in application techniques is offered where options are considered appropriate.
1.7 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
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
30-Jun-2007
ICS
77.040.20 - Non-destructive testing of metals
Technical Committee
E07 - Nondestructive Testing
Drafting Committee
E07.06 - Ultrasonic Method
Current Stage
Ref Project

Relations

Replaces
ASTM E1816-96(2002) - Standard Practice for Ultrasonic Examinations Using Electromagnetic Acoustic Transducer (EMAT) Techniques
Effective Date
01-Jul-2007
Replaced By
ASTM E1816-12 - Standard Practice for Ultrasonic Testing Using Electromagnetic Acoustic Transducer (EMAT) Techniques
Effective Date
01-Nov-2012
Referred By
ASTM E543-21 - Standard Specification for Agencies Performing Nondestructive Testing
Effective Date
01-Jul-2007
Referred By
ASTM E213-22 - Standard Practice for Ultrasonic Testing of Metal Pipe and Tubing
Effective Date
01-Jul-2007
Referred By
ASTM E1962-19 - Standard Practice for Ultrasonic Surface Testing Using Electromagnetic Acoustic Transducer (EMAT) Techniques
Effective Date
01-Jul-2007

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ASTM E1816-07 - Standard Practice for Ultrasonic Testing Using Electromagnetic Acoustic Transducer (EMAT) TechniquesASTM E1816-07 - Standard Practice for Ultrasonic Testing Using Electromagnetic Acoustic Transducer (EMAT) Techniques
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ASTM E1816-07 - Standard Practice for Ultrasonic Testing Using Electromagnetic Acoustic Transducer (EMAT) Techniques
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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:E1816 −07
StandardPractice for
Ultrasonic Testing Using Electromagnetic Acoustic
1
Transducer (EMAT) Techniques
This standard is issued under the fixed designation E1816; 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 techniques to address the given applications. Latitude in
application techniques is offered where options are considered
1.1 This practice covers procedures for the use of electro-
appropriate.
magnetic acoustic transducers (EMATs) for specific ultrasonic
examination applications. Recommendations are given for 1.7 The values stated in inch-pound units are to be regarded
specific applications for using EMAT techniques to detect as the standard. The values given in parentheses are for
flaws through both surface and volumetric examinations as information only.
well as to measure thickness.
1.8 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.2 These procedures recommend technical details and
responsibility of the user of this standard to establish appro-
guidelinesforthereliableandreproducibleultrasonicdetection
priate safety and health practices and determine the applica-
of flaws and thickness measurements using electromagnetic
bility of regulatory limitations prior to use.
acoustic transducers for both the pulsing and receiving of
ultrasonic waves. The EMAT techniques described herein can
2. Referenced Documents
be used as a basis for assessing the serviceability of various
2
components nondestructively, as well as for process control in
2.1 ASTM Standards:
manufacturing.
E114 Practice for Ultrasonic Pulse-Echo Straight-Beam
Contact Testing
1.3 These procedures cover noncontact techniques for cou-
E494 Practice for Measuring Ultrasonic Velocity in Materi-
pling ultrasonic energy into materials through the use of
als
electromagnetic fields. Surface, Lamb, longitudinal, and shear
E587 Practice for Ultrasonic Angle-Beam Contact Testing
wave modes are discussed.
E797 Practice for Measuring Thickness by Manual Ultra-
1.4 These procedures are intended to describe specific
sonic Pulse-Echo Contact Method
EMAT applications. These procedures are intended for appli-
E1316 Terminology for Nondestructive Examinations
cations in which the user has determined that the use of EMAT
E1774 Guide for Electromagnetic Acoustic Transducers
techniques can offer substantial benefits over conventional
(EMATs)
piezoelectric search units. It is not intended that EMAT
3
2.2 ASNT Standards:
techniques should be used in applications in which conven-
SNT-TC-1A Recommended Practice for Personnel Qualifi-
tional techniques and applications offer superior benefits (refer
cations and Certification in Nondestructive Testing
to Guide E1774).
ANSI/ASNT CP-189 Standard for Qualification and Certifi-
1.5 These procedures are applicable to any material in
cation of Nondestructive Testing Personnel
which acoustic waves can be introduced electromagnetically.
2.3 Military Standard:
This includes any material that is either electrically conductive
MIL-STD-410 Nondestructive Testing Personnel Qualifica-
or ferromagnetic.
4
tion and Certification
1.6 The procedures outlined in this practice address proven
EMATtechniques for specific applications; they do not purport
to address the only variation or all variations of EMAT
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
Standards volume information, refer to the standard’s Document Summary page on
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- the ASTM website.
3
structive Testing and is the direct responsibility of Subcommittee E07.06 on AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
Ultrasonic Method. 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
4
Current edition approved July 1, 2007. Published July 2007. Originally approved Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
in 1996. Last previous edition approved in 2002 as E1816 - 96(2002). DOI: Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
10.1520/E1816-07. www.dodssp.daps.mil.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E1816−07
3. Terminology produceoscillatingstresswavesperpendiculartothesurfaceof
the material to produce surface acoustic waves. Basic EMAT
3.1 Definitions—Related terminology is defined in Termi-
de
...

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4.1 CT may be performed on an object when it is in the as-cast, intermediate, or final machined condition. A CT examination can be used as a design tool to improve wax forms and moldings, establish process parameters, randomly check process control, perform final quality control (QC) examination for the acceptance or rejection of parts, and analyze failures and extend component lifetimes.  
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1.2.2 Performing metrological measurements and determining dimensional conformance; and  
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Standard Guide for Electromagnetic Acoustic Transducers (EMATs)

SIGNIFICANCE AND USE
4.1 General—Ultrasonic testing is a widely used nondestructive method for the examination of a material. The majority of ultrasonic examinations are performed using transducers that directly convert electrical energy into acoustic energy through the use of piezoelectric crystals. This guide describes an alternate technique in which electromagnetic energy is used to produce acoustic energy inside an electrically conductive or ferromagnetic material. EMATs have unique characteristics when compared to conventional piezoelectric ultrasonic search units, making them a significant tool for some ultrasonic examination applications.  
4.2 Principle—An electromagnetic acoustic transducer (EMAT) generates and receives ultrasonic waves without the need to contact the material in which the acoustic waves are traveling. The use of an EMAT requires that the material to be examined be electrically conductive or ferromagnetic, or both. There are two basic components of an EMAT system, a magnet and a coil. The magnet may be an electromagnet or a permanent magnet, which is used to produce a magnetic field in the material under test. The coil is driven using alternating current at the desired ultrasonic frequency. The coil and AC current also induce a surface magnetic field in the material under test. In the presence of the static magnetic field, the surface current experiences Lorentz forces that produce the desired ultrasonic waves. Upon reception of an ultrasonic wave, the surface of the conductor oscillates in the presence of a magnetic field, thus inducing a voltage in the coil. The transduction process occurs within an electromagnetic skin depth. The EMAT forms the basis for a very reproducible noncontact system for generating and detecting ultrasonic waves.  
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SCOPE
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4.1 The examination is performed by passing the tube lengthwise through or near an eddy current sensor energized with alternating current of one or more frequencies. The electrical impedance of the eddy current sensor is modified by the proximity of the tube. The extent of this modification is determined by the distance between the eddy current sensor and the tube, the dimensions, and electrical conductivity of the tube. The presence of metallurgical or mechanical discontinuities in the tube will alter the apparent impedance of the eddy current sensor. During passage of the tube, the changes in eddy current sensor characteristics caused by localized differences in the tube produce electrical signals which are amplified and modified to actuate either an audio or visual signaling device or a mechanical marker to indicate the position of discontinuities in the tube length. Signals can be produced by discontinuities located either on the external or internal surface of the tube or by discontinuities totally contained within the tube wall.  
4.2 The depth of penetration of eddy currents in the tube wall is influenced by the conductivity (alloy) of the material being examined and the excitation frequency employed. As defined by the standard depth of penetration equation, the eddy current penetration depth is inversely related to conductivity and excitation frequency (Note 2). Beyond one standard depth of penetration (SDP), the capacity to detect discontinuities by eddy currents is reduced. Electromagnetic examination of seamless aluminum alloy tube is most effective when the wall thickness does not exceed the SDP or in heavier tube walls when discontinuities of interest are within one SDP. The limit for detecting metallurgical or mechanical discontinuities by way of conventional eddy current sensors is generally accepted to be approximately three times the SDP point and is referred to as the effective depth of penetration (EDP).
Note 2: The standard depth of penetratio...
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1.2 Procedures for fabrication of reference standards are given in X1.1 and X2.1.  
1.3 This practice is intended for the examination of tubular products having nominal diameters up to 4 in. (101.6 mm) and wall thicknesses up to the standard depth of penetration (SDP) of eddy currents for the particular alloy (conductivity) being examined and the examination frequency being used.  
Note 1: This practice may also be used for larger diameters or heavier walls up to the effective depth of penetration (EDP) of eddy currents as long as adequate resolution is obtained and as specified by the using party or parties.  
1.4 This practice does not establish acceptance criteria. They must be established by the using party or parties.  
1.5 Units—The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that 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, 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.

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ASTM
ASTM E3024/E3024M-22a(Practice)
Standard Practice for Magnetic Particle Testing for General Industry

SIGNIFICANCE AND USE
4.1 Description of Process—Magnetic particle testing consists of magnetizing the area to be examined, applying suitably prepared magnetic particles while the area is magnetized, and subsequently interpreting and evaluating any resulting particle accumulations. Maximum detectability occurs when the discontinuity is positioned on the surface and perpendicular to the direction of magnetic flux in the part.  
4.2 This practice establishes the basic parameters for controlling the application of the magnetic particle testing method. This practice is written so that it can be specified on the engineering drawing, specification, or contract. It is not a detailed how-to procedure to be used by the examination personnel and, therefore, must be supplemented by a detailed written procedure that conforms to the requirements of this practice.
SCOPE
1.1 This practice establishes minimum requirements for magnetic particle testing used for the detection of surface or slightly subsurface discontinuities in ferromagnetic material. This practice is intended for industrial applications. Refer to Practice E1444/E1444M for aerospace applications. Guide E709 may be used in conjunction with this practice as a tutorial.  
1.2 The magnetic particle testing method is used to detect cracks, laps, seams, inclusions, and other discontinuities on or near the surface of ferromagnetic materials. Magnetic particle testing may be applied to raw material, billets, finished and semi-finished materials, welds, and in-service parts. Magnetic particle testing is not applicable to non-ferromagnetic metals and alloys such as austenitic stainless steels. See Appendix X1 for additional information.  
1.3 All areas of this practice may be open to agreement between the Level III or the cognizant engineering organization, as applicable, and the supplier.  
1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.4.1 This standard is a combined standard, an ASTM standard in which rationalized SI units and inch-pound units are included in the same standard, with each system of units to be regarded separately as standard.  
1.5 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.  
1.6 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.

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