1、Designation: E2096/E2096M 10Standard Practice forIn Situ Examination of Ferromagnetic Heat-Exchanger TubesUsing Remote Field Testing1This standard is issued under the fixed designation E2096/E2096M; the number immediately following the designation indicates the yearof original adoption or, in the ca
2、se 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 practice describes procedures to be followed duringremote field examination of insta
3、lled ferromagnetic heat-exchanger tubing for baseline and service-induced discontinui-ties.1.2 This practice is intended for use on ferromagnetic tubeswith outside diameters from 0.500 to 2.000 in. 12.70 to 50.80mm, with wall thicknesses in the range from 0.028 to 0.134 in.0.71 to 3.40 mm.1.3 This p
4、ractice does not establish tube acceptance criteria;the tube acceptance criteria must be specified by the usingparties.1.4 UnitsThe values stated in either inch-pound units orSI units are to be regarded separately as standard. The valuesstated in each system may not be exact equivalents; therefore,e
5、ach system shall be used independently of the other. Combin-ing values from the two systems may result in nonconformancewith the standard.1.5 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 practice to
6、establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing Nondestruc-tive TestingE1316 Terminology for Nondestructive Examinations2.2 Other Documents
7、:ASNT SNT-TC-1A Recommended Practice for Nonde-structive Testing Personnel Qualification and Certifica-tion3Can CGSB-48.9712-95 Qualification of NondestructiveTesting Personnel, Natural Resources Canada43. Terminology3.1 GeneralDefinitions of terms used in this practice canbe found in Terminology E1
8、316, Section A, “Common NDTTerms,” and Section C, “Electromagnetic Testing.”3.2 Definitions:3.2.1 detector, none or more coils or elements used tosense or measure magnetic field; also known as a receiver.3.2.2 exciter, na device that generates a time-varyingelectromagnetic field, usually a coil ener
9、gized with alternatingcurrent (ac); also known as a transmitter.3.2.3 nominal tube, na tube or tube section meeting thetubing manufacturers specifications, with relevant propertiestypical of a tube being examined, used for reference ininterpretation and evaluation.3.2.4 remote field, nas applied to
10、nondestructive testing,the electromagnetic field which has been transmitted throughthe test object and is observable beyond the direct couplingfield of the exciter.3.2.5 remote field testing, na nondestructive test methodthat measures changes in the remote field to detect andcharacterize discontinui
11、ties.3.2.6 using parties, nthe supplier and purchaser.3.2.6.1 DiscussionThe party carrying out the examinationis referred to as the “supplier,” and the party requesting theexamination is referred to as the “purchaser,” as required inForm and Style for ASTM Standards, April 2004. In commonusage outsi
12、de this practice, these parties are often referred to asthe “operator” and “customer,” respectively.3.3 Definitions of Terms Specific to This Standard:1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.07 onE
13、lectromagnetic Method.Current edition approved Sept. 1, 2010. Published October 2010. Originallyapproved in 2000. Last previous edition approved in 2005 as E2096 - 05. DOI:10.1520/E2096_E2096M-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
14、 serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.4Available from CGS
15、B Sales Centre; Place du Portage, Phase 3, 6B1; 11 LaurierStreet, Hull QC, Canada K1A 1G6.1*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.3.3.1 flaw characterization s
16、tandard, na standard used inaddition to the RFT system reference standard, with artificial orservice-induced flaws, used for flaw characterization.3.3.2 nominal point, na point on the phase-amplitudediagram representing data from nominal tube.3.3.3 phase-amplitude diagram, na two-dimensional rep-res
17、entation of detector output voltage, with angle representingphase with respect to a reference signal, and radius represent-ing amplitude (Fig. 1a and 1b).3.3.3.1 DiscussionIn this practice, care has been taken touse the term “phase angle” (and “phase”) to refer to an angularequivalent of time displa
18、cement, as defined in TerminologyE1316. When an angle is not necessarily representative of time,the general term “angle of an indication on the phase-amplitudediagram” is used.3.3.4 RFT system, nthe electronic instrumentation,probes, and all associated components and cables required forperforming RF
19、T.3.3.5 RFT system reference standard, na reference stan-dard with specified artificial flaws, used to set up and standard-ize a remote field system and to indicate flaw detectionsensitivity.3.3.6 sample ratethe rate at which data is digitized fordisplay and recording, in data points per second.3.3.
20、7 strip chart, na diagram that plots coordinates ex-tracted from points on a phase-amplitude diagram versus timeor axial position (Fig. 1c).3.3.8 zero point, na point on the phase-amplitude diagramrepresenting zero detector output voltage.3.3.8.1 DiscussionData on the phase-amplitude diagramare plot
21、ted with respect to the zero point. The zero point isseparate from the nominal point unless the detector is config-ured for zero output in nominal tube. The angle of a flawindication is measured about the nominal point.3.4 Acronyms:3.4.1 RFT, nremote field testing4. Summary of Practice4.1 The RFT da
22、ta is collected by passing a probe througheach tube. The electromagnetic field transmitted from theexciter to the detector is affected by discontinuities; by thedimensions and electromagnetic properties of the tube; and byobjects in and around the tube that are ferromagnetic orconductive. System sen
23、sitivity is verified using the RFT systemFIG. 1 A and B: Typical Phase-Amplitude Diagrams Used in RFT; C: Generic Strip Chart With FlawE2096/E2096M 102reference standard. System sensitivity and settings are checkedand recorded prior to and at regular intervals during theexamination. Data and system
24、settings are recorded in amanner that allows archiving and later recall of all data andsystem settings for each tube. Interpretation and evaluation arecarried out using one or more flaw characterization standards.The supplier generates a final report detailing the results of theexamination.5. Signif
25、icance and Use5.1 The purpose of RFT is to evaluate the condition of thetubing. The evaluation results may be used to assess thelikelihood of tube failure during service, a task which is notcovered by this practice.5.2 Principle of Probe OperationIn a basic RFT probe,the electromagnetic field emitte
26、d by an exciter travels outwardsthrough the tube wall, axially along the outside of tube, andback through the tube wall to a detector5(Fig. 2a).5.2.1 Flaw indications are created when (1) in thin-walledareas, the field arrives at the detector with less attenuation andless time delay, (2) discontinui
27、ties interrupt the lines ofmagnetic flux, which are aligned mainly axially, or (3) discon-tinuities interrupt the eddy currents, which flow mainly cir-cumferentially. A discontinuity at any point on the through-transmission path can create a perturbation; thus RFT hasapproximately equal sensitivity
28、to flaws on the inner and outerwalls of the tube.55.3 Warning Against Errors in Interpretation. Characteriz-ing flaws by RFT may involve measuring changes fromnominal (or baseline), especially for absolute coil data. Thechoice of a nominal value is important and often requiresjudgment. Practitioners
29、 should exercise care to use for nominalreference a section of tube that is free of damage (see definitionof “nominal tube” in 3.2.3). In particular, bends used asnominal reference must be free of damage, and tube supportplates used as nominal reference should be free of metal loss inthe plate and i
30、n adjacent tube material. If necessary, a comple-mentary technique (as described in 11.12) may be used toverify the condition of areas used as nominal reference.5.4 Probe ConfigurationThe detector is typically placedtwo to three tube diameters from the exciter, in a locationwhere the remote field do
31、minates the direct-coupling field.5Other probe configurations or designs may be used to optimizeflaw detection, as described in 9.3.5Schmidt, T. R., “The Remote Field Eddy Current Inspection Technique,”Materials Evaluation, Vol. 42, No. 2, Feb. 1984, pp. 225-230.NOTE 1Arrows indicate flow of electro
32、magnetic energy from exciter to detector. Energy flow is perpendicular to lines of magnetic flux.FIG. 2 RFT ProbesE2096/E2096M 1035.5 Comparison with Conventional Eddy-Current TestingConventional eddy-current test coils are typically configured tosense the field from the tube wall in the immediate v
33、icinity ofthe emitting element, whereas RFT probes are typically de-signed to detect changes in the remote field.6. Basis of Application6.1 The following items are subject to contractual agree-ment between the parties using or referencing this standard.6.2 Personnel QualificationIf specified in the
34、contractualagreement, personnel performing examinations to this standardshall be qualified in accordance with a nationally or interna-tionally recognized NDT personnel qualification practice orstandard such asANSI/ASNT-CP-189, SNT-TC-1A, NAS-410,or a similar document and certified by the employer or
35、certifying agency, as applicable. The practice or standard usedand its applicable revision shall be identified in the contractualagreement between the using parties.6.3 Qualification of Nondestructive Testing AgenciesIfspecified in the contractual agreement, NDT agencies shall bequalified and evalua
36、ted as specified in Practice E543, withreference to sections on electromagnetic testing. The appli-cable edition of Practice E543 shall be specified in thecontractual agreement.7. Job Scope and Requirements7.1 The following items may require agreement between theusing parties and should be specified
37、 in the purchase documentor elsewhere:7.1.1 Location and type of tube component to be examined,design specifications, degradation history, previous nonde-structive examination results, maintenance history, processconditions, and specific types of flaws that are required to bedetected, if known.7.1.2
38、 The maximum window of opportunity for work.(Detection of small flaws may require a slower probe pullspeed, which will affect productivity.)7.1.3 Size, material grade and type, and configuration oftubes to be examined.7.1.4 A tube numbering or identification system.7.1.5 Extent of examination, for e
39、xample: complete orpartial coverage, which tubes and to what length, whetherstraight sections only, and the minimum radius of bends thatcan be examined.7.1.6 Means of access to tubes, and areas where access maybe restricted.7.1.7 Type of RFT instrument and probe; and description ofreference standard
40、s used, including such details as dimensionsand material.7.1.8 Required operator qualifications and certification.7.1.9 Required tube cleanliness.7.1.10 Environmental conditions, equipment, and prepara-tions that are the responsibility of the purchaser; commonsources of noise that may interfere with
41、 the examination.NOTE 1Nearby welding activities may be a major source of interfer-ence.7.1.11 Complementary methods or techniques (includingpossible tube removal) that may be used to obtain additionalinformation.7.1.12 Acceptance criteria to be used in evaluating flawindications.7.1.13 Disposition
42、of examination records and referencestandards.7.1.14 Format and outline contents of the examinationreport.8. Interferences8.1 This section describes items and conditions which maycompromise RFT.8.2 Material Properties:8.2.1 Variations in the material properties of ferromagnetictubes are a potential
43、source of inaccuracy. Impurities, segrega-tion, manufacturing process, grain size, stress history, presentstress patterns, temperature history, present temperature, mag-netic history, and other factors will affect the electromagneticresponse measured during RFT. The conductivity and perme-ability of
44、 tubes with the same grade of material are oftenmeasurably different. It is common to find that some of thetubes to be examined are newer tubes with different materialproperties.8.2.2 Permeability variations may occur at locations wherethere was uneven temperature or stress during tube manufac-ture,
45、 near welds, at bends, where there were uneven heattransfer conditions during service, at areas where there is coldworking (such as that created by an integral finning process),and in other locations. Indications from permeability variationsmay be mistaken for, or obscure flaw indications. Effects m
46、aybe less severe in tubes that were stress-relieved during manu-facture.8.2.3 Residual stress, with accompanying permeabilityvariations, may be present when discontinuities are machinedinto a reference standard, or during the integral finning process.8.2.4 RFT is affected by residual magnetism in th
47、e tubing,including residual magnetism created during a previous exami-nation using another magnetic method. Tubes with significantresidual magnetism should be demagnetized prior to RFT.8.3 Ferromagnetic and Conductive Objects:8.3.1 Objects near the tube that are ferromagnetic or con-ductive may redu
48、ce the sensitivity and accuracy of flawcharacterization in their immediate vicinity. Such objects mayin some cases be mistaken for flaws. Knowledge of themechanical layout of the component to be examined is recom-mended. Examples of ferromagnetic or conductive objectsinclude: tube support plates, ba
49、ffle plates, end plates, tubesheets, anti-vibration bars, neighboring tubes, impingementplates, loose parts, and attachments clamped or welded to atube.NOTE 2Interference from ferromagnetic or conductive objects can beof practical use when RFT is used to confirm the position of an objectinstalled on a tube or to detect where objects have become detached andhave fallen against a tube.8.3.2 Neighboring Tubes:E2096/E2096M 1048.3.2.1 In areas where there is non-constant tube spacing(bowing) or where tubes cross close to each other, there areindication
