ASTM E243-18

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: E243 − 13 E243 − 18
Standard Practice for
Electromagnetic (Eddy Current) Examination of Copper and
Copper-Alloy Tubes
This standard is issued under the fixed designation E243; 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 the procedures that shall be followed in eddy current examination of copper and copper-alloy tubes
for detecting discontinuities of a severity likely to cause failure of the tube. These procedures are applicable for tubes with outside
diameters to 3 ⁄8 in. (79.4 mm), inclusive, and wall thicknesses from 0.017 in. (0.432 mm) to 0.120 in. (3.04 mm), inclusive, or
as otherwise stated in ASTM product specifications; or by other users of this practice. These procedures may be used for tubes
beyond the size range recommended, upon contractual agreement between the purchaser and the manufacturer.
1.2 The procedures described in this practice are based on methods making use of encircling annular examination coil systems.
1.3 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.
NOTE 1—This practice may be used as a guideline for the examination, by means of internal probe examination coil systems, of installations using
tubular products where the outer surface of the tube is not accessible. For such applications, the technical differences associated with the use of internal
probe coils should be recognized and accommodated. The effect of foreign materials on the tube surface and signals due to tube supports are typical of
the factors that must be considered. See E690 for additional details regarding the in-situ examinations using internal probes.
1.4 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.
1.5 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
2.1 ASTM Standards:
B111/B111M Specification for Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock
B395/B395M Specification for U-Bend Seamless Copper and Copper Alloy Heat Exchanger and Condenser Tubes
B543 Specification for Welded Copper and Copper-Alloy Heat Exchanger Tube
E543 Specification for Agencies Performing Nondestructive Testing
E690 Practice for In Situ Electromagnetic (Eddy Current) Examination of Nonmagnetic Heat Exchanger Tubes
E1316 Terminology for Nondestructive Examinations
2.2 Other Documents:
SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing
ANSI/ASNT CP-189 ASNT Standard for Qualification and Certification of Nondestructive Testing Personnel
NAS-410 NAS Certification and Qualification of Nondestructive Personnel (Quality Assurance Committee)
This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.07 on Electromagnetic
Method.
Current edition approved Dec. 1, 2013June 1, 2018. Published December 2013June 2018. Originally approved in 1967. Last previous edition approved in 20092013 as
E243 - 09.E243 - 13. DOI: 10.1520/E0243-13.10.1520/E0243-18.
For ASME Boiler and Pressure Vessel Code applications see related Practice SE-243 in the Code.
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 the ASTM website.
Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
Available from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, http://www.aia-aerospace.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
E243 − 18
2.3 International Standards:
ISO 9712 Non-Destructive Testing – Qualification and Certification of NDT personnel
3. Terminology
3.1 Definitions of Terms Specific to this Standard
3.1.1 The following terms are defined in relation to this standard.
3.1.1.1 artificial discontinuity reference standard—a standard consisting of a selected tube with defined artificial discontinuities,
used when adjusting the system controls to obtain some predetermined system output signal level. This standard may be used for
periodic checking of the instrument during an examination.
3.1.1.2 percent maximum unbalance standardization standard—a method of standardization that can be used with speed-
insensitive instruments (see 3.1.1.4). The acceptance level of the examination is established at the operating examination frequency
as an accurate fraction of the maximum unbalance signal resulting from the end effect of a tube. Any low-noise tube from the
production run having a squared end may be used as this standard. This standard may be used for periodic checking of the
instrument during an examination.
3.1.1.3 electrical center—the center established by the electromagnetic field distribution within the examination coil. A
constant-intensity signal, irrespective of the circumferential position of a discontinuity, is indicative of electrical centering. The
electrical center may be different from the physical center of the examination coil.
3.1.1.4 speed-sensitive equipment—examination equipment that produces a variation in signal response with variations in the
examination speed. Speed-insensitive equipment provides a constant signal response with changing examination speeds.
3.1.1.5 off-line examining—examining / in-line—eddy current examinations conducted on equipment that includes the
examination coil and means to propel individual tubes under examination through the coil at appropriate speeds and conditions.
3.1.1.6 on-line examining—eddy current examinations conducted on equipment that includes the examination coil and means
to propel tubes under examination through the coil at appropriate speeds and conditions as an integral part of a continuous tube
manufacturing sequence.
3.2 Definitions of Terms—Refer to Terminology E1316 for definitions of terms that are applicable to nondestructive
examinations in general.
4. Summary of Practice
4.1 Examining is usually performed by passing the tube lengthwise through a coil energized with alternating current at one or
more frequencies. The electrical impedance of the coil is modified by the proximity of the tube, the tube dimensions, electrical
conductivity and magnetic permeability of the tube material, and metallurgical or mechanical discontinuities in the tube. During
passage of the tube, the changes in electromagnetic response caused by these variables in the tube produce electrical signals which
are processed so as to actuate an audio or visual signaling device or mechanical marker which produces a record.
5. Significance and Use
5.1 Eddy current testing is a nondestructive method of locating discontinuities in a product. Signals can be produced by
discontinuities located either on the external or internal surface of the tube or by discontinuities totally contained within the walls.
Since the density of eddy currents decreases nearly exponentially as the distance from the external surface increases, the response
to deep-seated defects decreases.
5.2 Some indications obtained by this method may not be relevant to product quality; for example, a reject signal may be caused
by minute dents or tool chatter marks that are not detrimental to the end use of the product. Irrelevant indications can mask
unacceptable discontinuities. Relevant indications are those which result from nonacceptable discontinuities. Any indication above
the reject level that is believed to be irrelevant shall be regarded as unacceptable until it is demonstrated by re-examination or other
means to be irrelevant (see 10.3.2).
5.3 Eddy current testing systems are generally not sensitive to discontinuities adjacent to the ends of the tube (end effect).
On-line eddy current examining would not be subject to end effect.
5.4 Discontinuities such as scratches or seams that are continuous and uniform for the full length of the tube may not always
be detected.
6. Basis of Application
6.1 Personnel Qualification—Nondestructive testing (NDT) personnel shall be qualified in accordance with a nationally
recognized NDT personnel qualification practice or standard such as ANSI/ASNT CP-189, SNT-TC-1A, MIL-STD-410, NAS-410,
ISO 9712, or a similar document. The practice or standard used and its applicable revision shall be specified in the purchase
specification or contractual agreement between the using parties.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
E243 − 18
NOTE 2—MIL-STD-410 is canceled and has been replaced with NAS-410, however, it may be used with agreement between contracting parties.
6.2 Qualification of Nondestructive Testing Agencies—If specified in the purchase specification or contractual agreement, NDT
agencies shall be evaluated and qualified as described in Practice E543. The applicable edition of Practice E543 shall be identified
in the purchase specification or contractual agreement between the using parties.
7. Apparatus
7.1 Electronic Apparatus—The electronic apparatus shall be capable of energizing the examination coil with alternating currents
of suitable frequencies (for example, 1 kHz to 125 kHz), and shall be capable of sensing the changes in the electromagnetic
response of the coils. Electrical signals produced in this manner are processed so as to actuate an audio or visual signaling device
or mechanical marker which produces a record.
7.2 Examination Coils—Examination coils shall be capable of inducing current in the tube and sensing changes in the electrical
characteristics of the tube. The examination coil diameter should be selected to yield the largest practical fill-factor.
7.3 Driving Mechanism—A mechanical means of passing the tube through the examination coil with minimum vibration of the
examination coil or the tube. The device shall maintain the tube substantially concentric with the electrical center of the
examination coil. A uniform speed (65.0 % speed variation maximum) shall be maintained.
7.4 End Effect Suppression Device—A means capable of suppressing the signals produced at the ends of the tube. Individual
ASTM product specifications shall specify when an end effect suppression device is mandatory.
NOTE 3—Signals close to the ends of the tube may carry on beyond the limits of end suppression. Refer to 9.59.4.
8. Reference Standards
8.1 Artificial Discontinuity Reference Standard:
8.1.1 The tube used when adjusting the sensitivity setting of the apparatus shall be selected from a typical production run and
shall be representative of the purchaser’s order. The tubes shall be passed through the examination coil with the instrument
sensitivity high enough to determine the nominal background noise inherent in the tubes. The reference standard shall be selected
from tubes exhibiting low background noise. For on-line eddy current examining, the reference standard is created in a tube portion
existent in the continuous manufacturing sequence or in other forms as allowed by the product specification.
8.1.2 The artificial discontinuities shall be spaced to provide signal resolution adequate for interpretation. The artificial
discontinuities shall be prepared in accordance with one of the following options:
(a) A round bottom transverse notch on the outside of the tube in each of three successive transverse planes at 0, 120, and 240°
(Fig. 1).
FIG. 1 Reference Standard with Three Notches
(b) A hole drilled radially through the tube wall in each of three successive transverse planes at 0, 120, and 240° (Fig. 2).
FIG. 2 Reference Standard with Three Holes
(c) One round bottom transverse notch on the outside of the tube at 0° and another
...