ASTM E376-11
(Practice)Standard Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current (Electromagnetic) Testing Methods
Standard Practice for Measuring Coating Thickness by Magnetic-Field or Eddy-Current (Electromagnetic) Testing Methods
SIGNIFICANCE AND USE
General—No presently available thickness gauge is applicable to all combinations of coating-substrate thicknesses and materials. The limitations of a particular instrument are generally delineated by its manufacturer.
Magnetic—Magnetic-type gauges measure either magnetic attraction between a magnet and a coating or its substrate, or reluctance of a magnetic flux path passing through the coating and substrate. These gauges are designed to measure thickness of a nonmagnetic coating on a magnetic substrate. Some of them will also measure thickness of nickel coatings on a magnetic or nonmagnetic substrate.
Eddy Current—Eddy-current-type thickness gauges are electronic instruments that measure variations in impedance of an eddy-current inducing coil caused by coating thickness variations. They can only be used if the electrical conductivity of the coating differs significantly from that of the substrate.
Accuracy—The accuracy of a measurement depends on the instrument, its calibration and standardization, and its operating conditions. The accuracy is also affected by the interferences listed in Section 5, such as part geometry (curvature), magnetic permeability, and surface roughness.
Note 2—This practice allows the coating thickness to be determined within ±10 % of its true thickness or to within ±2.5 μm (or ±0.0001-in.), whichever is the greater. (See exceptions in Appendix X2.)
SCOPE
1.1 This practice covers the use of magnetic- and eddy-current-type thickness instruments (gauges) for nondestructive thickness measurement of a coating on a metal substrate.
1.2 More specific uses of these instruments are covered by Practice D7091 and the following test methods issued by ASTM: Test Methods B244, B499, B530, and G12.
1.3 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.
1.4 Measurements made in accordance with this practice will be in compliance with the requirements of ISO 2178 as printed in 1982.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E376 − 11
Standard Practice for
Measuring Coating Thickness by Magnetic-Field or Eddy-
1
Current (Electromagnetic) Testing Methods
This standard is issued under the fixed designation E376; 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 Department of Defense.
1. Scope* by the Magnetic Method: Electrodeposited Nickel Coat-
ings on Magnetic and Nonmagnetic Substrates
1.1 This practice covers the use of magnetic- and eddy-
D7091 Practice for Nondestructive Measurement of Dry
current-type thickness instruments (gauges) for nondestructive
Film Thickness of Nonmagnetic Coatings Applied to
thickness measurement of a coating on a metal substrate.
Ferrous Metals and Nonmagnetic, Nonconductive Coat-
1.2 More specific uses of these instruments are covered by
ings Applied to Non-Ferrous Metals
Practice D7091 and the following test methods issued by
E543 Specification forAgencies Performing Nondestructive
ASTM: Test Methods B244, B499, B530, and G12.
Testing
1.3 Units—The values stated in SI units are to be regarded E1316 Terminology for Nondestructive Examinations
G12 Test Method for Nondestructive Measurement of Film
as standard. The values given in parentheses are mathematical
conversions to inch-pound units that are provided for informa- Thickness of Pipeline Coatings on Steel
3
2.2 ASNT Standards:
tion only and are not considered standard.
SNT-TC-1A Recommended Practice for Personnel Qualifi-
1.4 Measurements made in accordance with this practice
cation and Certification in Nondestructive Testing
will be in compliance with the requirements of ISO 2178 as
ANSI/ASNT-CP-189 Standard for Qualification and Certifi-
printed in 1982.
cation of NDT Personnel
1.5 This standard does not purport to address all of the
2.3 AIA Standard:
safety concerns, if any, associated with its use. It is the
NAS-410 Certification and Qualification of Nondestructive
responsibility of the user of this standard to establish appro- 4
Testing Personnel
priate safety and health practices and determine the applica-
2.4 International Standard:
bility of regulatory limitations prior to use.
ISO 2178 Nonmagnetic Coatings on Magnetic Substrate—
Measurement of Coating Thickness—Magnetic
2. Referenced Documents
5
Method
2
2.1 ASTM Standards:
NOTE 1—See Appendix X1.
B244 Test Method for Measurement of Thickness ofAnodic
Coatings on Aluminum and of Other Nonconductive
3. Terminology
Coatings on Nonmagnetic Basis Metals with Eddy-
3.1 Definitions—For definitions of terms relating to this
Current Instruments
practice, refer to Terminology E1316.
B499 Test Method for Measurement of Coating Thicknesses
by the Magnetic Method: Nonmagnetic Coatings on
4. Significance and Use
Magnetic Basis Metals
4.1 General—No presently available thickness gauge is
B530 Test Method for Measurement of Coating Thicknesses
applicable to all combinations of coating-substrate thicknesses
and materials. The limitations of a particular instrument are
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- generally delineated by its manufacturer.
structive Testing and is the direct responsibility of Subcommittee E07.07 on
Electromagnetic Method.
3
Current edition approved July 1, 2011. Published July 2011. Originally approved AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
in 1989. Last previous edition approved in 2006 as E376 – 06. DOI: 10.1520/ 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
4
E0376-11. Available fromAerospace IndustriesAssociation ofAmerica, Inc. (AIA), 1000
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or WilsonBlvd.,Suite1700,Arlington,VA22209-3928,http://www.aia-aerospace.org.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM (Replacement standard for MIL-STD-410.)
5
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
*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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E376 − 11
4.2 Magnetic—Magnetic-type gauges measure either mag- ments made too near an edge or inside corner will not be valid
neticattractionbetweenamagnetandacoatingoritssubstrate, unless the instrument is specifically standardized for such a
1 1
or reluctance
...
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:E376–06 Designation: E376 – 11
Standard Practice for
Measuring Coating Thickness by Magnetic-Field or Eddy-
1
Current (Electromagnetic) ExaminationTesting Methods
This standard is issued under the fixed designation E376; 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 Department of Defense.
1. Scope
1.1This practice covers the use of magnetic- and eddy-current-type thickness instruments (gages) for nondestructive thickness
measurement of a coating on a metal substrate. *
1.1 This practice covers the use of magnetic- and eddy-current-type thickness instruments (gauges) for nondestructive thickness
measurement of a coating on a metal substrate.
1.2 More specific uses of these instruments are covered by Practice D7091 and the following test methods issued by ASTM:
Test Methods B244, B499, B530, and G12.
1.3The values stated in SI units are to be regarded as standard.The inch-pound units in parentheses are for information only and
may be approximate.
1.3 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical
conversions to inch-pound units that are provided for information only and are not considered standard.
1.4 Measurements made in accordance with this practice will be in compliance with the requirements of ISO 2178 as printed
in 1982.
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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
B244 Test Method for Measurement of Thickness ofAnodic Coatings onAluminum and of Other Nonconductive Coatings on
Nonmagnetic Basis Metals with Eddy-Current Instruments
B499 Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic
Basis Metals
B530 Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Electrodeposited Nickel Coatings on
Magnetic and Nonmagnetic Substrates
D7091 Practice for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to Ferrous Metals
and Nonmagnetic, Nonconductive Coatings Applied to Non-Ferrous Metals
E543 Specification for Agencies Performing Nondestructive Testing
E1316 Terminology for Nondestructive Examinations
G12 Test Method for Nondestructive Measurement of Film Thickness of Pipeline Coatings on Steel
3
2.2 ASNT Standards:
SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing
ANSI/ASNT-CP-189 Standard for Qualification and Certification of NDT Personnel
2.3 AIA Standard:
4
NAS-410 Certification and Qualification of Nondestructive Testing Personnel
1
This practice is under the jurisdiction ofASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.07 on Electromagnetic
Method.
Current edition approved Dec.July 1, 2006.2011. Published January 2007.July 2011. Originally approved in 1989. Last previous edition approved in 20032006 as
E376 – 036. DOI: 10.1520/E0376-06.10.1520/E0376-11.
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.
3
Available from The American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
4
Available from Aerospace Industries Association of America, Inc., 1250 Eye St., NW, Washington, DC 20005. (Replacement standard for MIL-STD-410.)
*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
---------------------- Page: 1 ----------------------
E376 – 11
2.4 International Standard:
ISO 2178 Nonmagnetic Coatings on Magnetic Substrate—Measurement of Coating Thickness—Magnetic
5
Method
NOTE 1—See Appendix X1.
3. Terminology
3.1Definitions—Definitions of terms relating to electromagnetic examination are given in Terminolog
...
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