1、Designation: E 243 97 (Reapproved 2004)e1Standard Practice forElectromagnetic (Eddy-Current) Examination of Copper andCopper-Alloy Tubes1This standard is issued under the fixed designation E 243; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.e1NOTEEditorial changes
3、 were made throughout the standard in January 2004.1. Scope1.1 This practice2covers the procedures that shall befollowed in eddy-current examination of copper and copper-alloy tubes for detecting discontinuities of a severity likely tocause failure of the tube. These procedures are applicable fortub
4、es with outside diameters to 318 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 productspecifications; or by other users of this practice. These proce-dures may be used for tubes beyond the size range recom-mended, u
5、pon contractual agreement between the purchaserand the manufacturer.1.2 The procedures described in this practice are based onmethods making use of encircling annular examination coilsystems.1.3 The values stated in inch-pound units are to be regardedas the standard.NOTE 1This practice may be used a
6、s a guideline for the examination,by means of internal probe examination coil systems, of installations usingtubular products where the outer surface of the tube is not accessible. Forsuch applications, the technical differences associated with the use ofinternal probe coils should be recognized and
7、 accommodated. The effectof foreign materials on the tube surface and signals due to tube supportsare typical of the factors that must be considered.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this s
8、tandard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3B 111 Specification for Copper and Copper-Alloy SeamlessCondenser Tubes and Ferrule StockB 395 Specification for U-Bend Sea
9、mless Copper and Cop-per Alloy Heat Exchanger and Condenser TubesB 543 Specification for Welded Copper and Copper-AlloyHeat Exchanger TubeE 543 Practice for Evaluating Agencies that Perform Non-destructive TestingE 1316 Terminology for Nondestructive Examinations2.2 Other Documents:SNT-TC-1A Recomme
10、nded Practice for NondestructiveTesting Personnel Qualification and Certification4ANSI/ASNT CP-189 ASNT Standard for Qualification andCertification of Nondestructive Testing Personnel4NAS-410 NAS Certification and Qualification of Nonde-structive Personnel (Quality Assurance Committee)53. Terminolog
11、y3.1 Definitions of Terms Specific to this Standard3.1.1 The following terms are defined in relation to thisstandard.3.1.1.1 artificial discontinuity reference standarda stan-dard consisting of a selected tube with defined artificialdiscontinuities, used when adjusting the system controls toobtain s
12、ome predetermined system output signal level. Thisstandard may be used for periodic checking of the instrumentduring an examination.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.07 onElectromagnetic Meth
13、ods.Current edition approved January 1, 2004. Published February 2004. Originallyapproved in 1967. Last previous edition approved in 1997 as E 243 - 97.2For ASME Boiler and Pressure Vessel Code applications see related PracticeSE-243 in the Code.3For referenced ASTM standards, visit the ASTM website
14、, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from The American Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Ln., Columbus
15、, OH 43228-0518.5Available from Aerospace Industries Association of America, Inc., 1250 EyeSt., NW, Washington, DC 20005.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1.2 percent maximum unbalance standardizationstandarda metho
16、d of standardization that can be used withspeed-insensitive instruments (see 3.1.1.4). The acceptancelevel of the examination is established at the operating exami-nation frequency as an accurate fraction of the maximumunbalance signal resulting from the end effect of a tube. Anylow-noise tube from
17、the production run having a squared endmay be used as this standard. This standard may be used forperiodic checking of the instrument during an examination.3.1.1.3 electrical centerthe center established by the elec-tromagnetic field distribution within the examination coil. Aconstant-intensity sign
18、al, irrespective of the circumferentialposition of a discontinuity, is indicative of electrical centering.The electrical center may be different from the physical centerof the examination coil.3.1.1.4 speed-sensitive equipmentexamination equipmentthat produces a variation in signal response with var
19、iations inthe examination speed. Speed-insensitive equipment provides aconstant signal response with changing examination speeds.3.1.1.5 off-line examiningeddy-current examinations con-ducted on equipment that includes the examination coil andmeans to propel individual tubes under examination throug
20、hthe coil at appropriate speeds and conditions.3.1.1.6 on-line examiningeddy-current examinations con-ducted on equipment that includes the examination coil andmeans to propel tubes under examination through the coil atappropriate speeds and conditions as an integral part of acontinuous tube manufac
21、turing sequence.3.2 Definitions of TermsRefer to Terminology E 1316 fordefinitions of terms that are applicable to nondestructiveexaminations in general.4. Summary of Practice4.1 Examining is usually performed by passing the tubelengthwise through a coil energized with alternating current atone or m
22、ore frequencies. The electrical impedance of the coilis modified by the proximity of the tube, the tube dimensions,electrical conductivity and magnetic permeability of the tubematerial, and metallurgical or mechanical discontinuities in thetube. During passage of the tube, the changes in electromag-
23、netic response caused by these variables in the tube produceelectrical signals which are processed so as to actuate an audioor visual signaling device or mechanical marker which pro-duces a record.5. Significance and Use5.1 Eddy-current examination is a nondestructive method oflocating discontinuiti
24、es in a product. Signals can be producedby discontinuities located either on the external or internalsurface of the tube or by discontinuities totally containedwithin the walls. Since the density of eddy currents decreasesnearly exponentially as the distance from the external surfaceincreases, the r
25、esponse to deep-seated defects decreases.5.2 Some indications obtained by this method may not berelevant to product quality; for example, a reject signal may becaused by minute dents or tool chatter marks that are notdetrimental to the end use of the product. Irrelevant indicationscan mask unaccepta
26、ble discontinuities. Relevant indicationsare those which result from nonacceptable discontinuities. Anyindication above the reject level that is believed to be irrelevantshall be regarded as unacceptable until it is demonstrated byre-examination or other means to be irrelevant (see 10.3.2).5.3 Eddy-
27、current examination systems are generally notsensitive to discontinuities adjacent to the ends of the tube (endeffect). On-line eddy-current examining would not be subjectto end effect.5.4 Discontinuities such as scratches or seams that arecontinuous and uniform for the full length of the tube may n
28、otalways be detected.6. Basis of Application6.1 Personnel QualificationNondestructive testing (NDT)personnel shall be qualified in accordance with a nationallyrecognized NDT personnel qualification practice or standardsuch as ANSI/ASNT CP-189, SNT-TC-1A, MIL-STD-410,NAS-410, or a similar document. T
29、he practice or standard usedand its applicable revision shall be specified in the purchasespecification or contractual agreement between the usingparties.NOTE 2MIL-STD-410 is canceled and has been replaced with NAS-410, however, it may be used with agreement between contracting parties.6.2 Qualifica
30、tion of Nondestructive Testing AgenciesIfspecified in the purchase specification or contractual agree-ment, NDT agencies shall be evaluated and qualified asdescribed in Practice E 543. The applicable edition of PracticeE 543 shall be identified in the purchase specification orcontractual agreement b
31、etween the using parties.7. Apparatus7.1 Electronic ApparatusThe electronic apparatus shallbe capable of energizing the examination coil with alternatingcurrents of suitable frequencies (for example, 1 kHz to 125kHz), and shall be capable of sensing the changes in theelectromagnetic response of the
32、coils. Electrical signals pro-duced in this manner are processed so as to actuate an audio orvisual signaling device or mechanical marker which producesa record.7.2 Examination CoilsExamination coils shall be capableof inducing current in the tube and sensing changes in theelectrical characteristics
33、 of the tube. The examination coildiameter should be selected to yield the largest practicalfill-factor.7.3 Driving MechanismA mechanical means of passingthe tube through the examination coil with minimum vibrationof the examination coil or the tube. The device shall maintainthe tube substantially c
34、oncentric with the electrical center ofthe examination coil. A uniform speed (65.0 % speed variationmaximum) shall be maintained.7.4 End Effect Suppression DeviceA means capable ofsuppressing the signals produced at the ends of the tube.Individual ASTM product specifications shall specify when anend
35、 effect suppression device is mandatory.NOTE 3Signals close to the ends of the tube may carry on beyond thelimits of end suppression. Refer to 9.5.8. Reference Standards8.1 Artificial Discontinuity Reference Standard:E 243 97 (2004)e128.1.1 The tube used when adjusting the sensitivity setting ofthe
36、apparatus shall be selected from a typical production runand shall be representative of the purchasers order. The tubesshall be passed through the examination coil with the instru-ment sensitivity high enough to determine the nominal back-ground noise inherent in the tubes. The reference standard sh
37、allbe selected from tubes exhibiting low background noise. Foron-line eddy-current examining, the reference standard iscreated in a tube portion existent in the continuous manufac-turing sequence or in other forms as allowed by the productspecification.8.1.2 The artificial discontinuities shall be s
38、paced to providesignal resolution adequate for interpretation. The artificialdiscontinuities shall be prepared in accordance with one of thefollowing options:(a) A round bottom transverse notch on the outside of thetube in each of three successive transverse planes at 0, 120, and240 (Fig. 1).(b) A h
39、ole drilled radially through the tube wall in each ofthree successive transverse planes at 0, 120, and 240 (Fig. 2).(c) One round bottom transverse notch on the outside ofthe tube at 0 and another at 180, and one hole drilled radiallythrough the wall at 90 and another at 270. Only one notch orhole s
40、hall be made in each transverse plane (Fig. 3).(d) Four round bottom transverse notches on the outside ofthe tube, all on the same element of the tube (Fig. 4).(e) Four holes drilled radially through the tube wall, all thesame element of the tube (Fig. 5).8.1.2.1 Round Bottom Transverse NotchThe not
41、ch shallbe made using a suitable jig with a 0.250-in. 6.35-mmdiameter No. 4 cut, straight, round file. The outside surface ofthe tube shall be stroked in a substantially straight lineperpendicular to the axis of the tube. The notch depth shall bein accordance with the ASTM product specification or A
42、ppen-dix X1 if the product specification does not specify and shallnot vary from the notch depth by more than 60.0005 in.60.013 mm when measured at the center of the notch (seeTable X1.1).6NOTE 4Tables X1.1 and X1.2 should not be used for acceptance orrejection of materials.8.1.2.2 Drilled HolesThe
43、hole shall be drilled radiallythrough the wall using a suitable drill jig that has a bushing toguide the drill, care being taken to avoid distortion of the tubewhile drilling. The drilled hole diameter shall be in accordancewith the ASTM product specification or Appendix X1 if theproduct specificati
44、on does not specify and shall not vary bymore than +0.001, 0.000 in. +0.026 mm of the hole diam-eter specified (see Table X1.2) (Note 4).68.1.2.3 Other Artificial DiscontinuitiesDiscontinuities ofother contours may be used in the reference standard by mutualagreement between supplier and purchaser.6
45、Tables X1.1 and X1.2 are extracted from Specifications B 111, B 395, andB 543.FIG. 1 Reference Standard with Three NotchesFIG. 2 Reference Standard with Three HolesNOTE 1A = Space to provide signal resolution adequate for interpre-tation.FIG. 3 Reference Standard with Two Notches and Two HolesNOTE 1
46、A = Space to provide signal resolution adequate for interpre-tation.FIG. 4 Reference Standard with Four Notches in LineNOTE 1A = Space to provide signal resolution adequate for interpre-tation.FIG. 5 Reference Standard with Four Holes in LineE 243 97 (2004)e138.2 Percent Maximum Unbalance Reference
47、StandardThis method of standardization shall be used only withspeed-insensitive equipment, and equipment specifically de-signed or adapted to accommodate the use of this calibrationmethod. Maximum unbalance of differential coils is obtainedby placing the squared end of a tube in only one of thediffe
48、rential coils and using an accurately calibrated attenuatorto obtain the (100 %) maximum unbalance signal. A percentageof the maximum unbalance signal shall define the examinationacceptance level at a specific operating frequency and thispercentage shall be obtained from the ASTM product specifi-cat
49、ion.8.3 Other Reference StandardsOther reference standardsmay be used by mutual agreement between supplier andpurchaser.NOTE 5Artificial discontinuities and the percent of maximum unbal-ance are not intended to be representative of natural discontinuities orproduce a direct relationship between instrument response and disconti-nuity severity; they are intended only for establishing sensitivity levels asoutlined in Section 9. The relationship between instrument response anddiscontinuity size, shape, and location is important and should
