1、Designation: E2928/E2928M 17Standard Practice forExamination of Drillstring Threads Using the AlternatingCurrent Field Measurement Technique1This standard is issued under the fixed designation E2928/E2928M; the number immediately following the designation indicates the yearof original adoption or, i
2、n 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. Scope1.1 This practice describes procedures to be followed duringalternating current field
3、measurement examination of drill-string threads on tubulars used for oil and gas exploration andproduction for detection and, if required, sizing of service-induced surface breaking discontinuities transverse to the pipe.1.2 This practice is intended for use on threads in anymetallic material.1.3 Th
4、is practice does not establish acceptance criteria.Typical industry practice is to reject these connections ondetection of a confirmed crack.1.4 While the alternating current field measurement tech-nique is capable of detecting discontinuities in theseconnections, supplemental surface NDT methods su
5、ch asmagnetic particle testing for ferrous metals and penetranttesting for non-ferrous metals may detect more discontinuities.1.5 UnitsThe values stated in either inch-pound units orSI units are to be regarded separately as standard. The valuesstated in each system might not be exact equivalents; th
6、erefore,each system shall be used independently of the other. Combin-ing values from the two systems may result in nonconformancewith the standard.1.6 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 sta
7、ndard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles fo
8、r theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing NondestructiveTestingE1316 Terminology for Nondestructive E
9、xaminationsE2261 Practice for Examination of Welds Using the Alter-nating Current Field Measurement Technique2.2 ASNT Standards3SNT-TC-1A Personnel Qualification and Certification inNondestructive TestingANSI/ASNT-CP-189 Standard for Qualification and Certifi-cation of Nondestructive Testing Personn
10、el2.3 ISO Standard:4ISO 9712 Non-Destructive Testing: Qualification and Certi-fication of NDT Personnel3. Terminology3.1 For definitions of terms relating to this practice refer toTerminology E1316, Section A, Common NDT terms, andSection C, Electromagnetic testing. The following definitionsare spec
11、ific to the alternating current field measurement tech-nique:3.2 Definitions:3.2.1 detectorone or more coils or elements used to senseor measure a magnetic field; also known as a receiver.3.2.2 excitera device that generates a time varying elec-tromagnetic field, usually a coil energized with altern
12、atingcurrent (AC); also known as a transmitter.3.2.3 uniform fieldas applied to nondestructive testingwith magnetic fields, the area of uniform magnetic field overthe surface of the material under examination produced by aparallel induced alternating current, which has been passed1This practice is u
13、nder the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.07 onElectromagnetic Method.Current edition approved June 1, 2017. Published June 2017. Originallyapproved in 2013. Last previous edition approved in 2013 as D2928/D2928M13.DOI
14、: 10.1520/E2928_E2928M17.2For referenced ASTM standards, visit the ASTM website, 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.3Available fromAmerican Society for
15、Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.4Available from International Organization for Standardization (ISO), ISOCentral Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.Cop
16、yright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of Internat
17、ional Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1through the testpiece and is observable beyond the directcoupling of the exciting coil.3.3 Definitions of Terms Specific to This Standard:3.3.1 alternating current field me
18、asurement systemtheelectronic instrumentation, software, probes, and all associatedcomponents and cables required for performing an examinationusing the alternating current field measurement technique.3.3.2 boxthe female thread in a drillstring connection.3.3.3 Bxthe x component of the magnetic fiel
19、d, parallel tothe thread root, the magnitude of which is proportional to thecurrent density set up by the electric field.3.3.4 Bzthe z component of the magnetic field normal tothe examined pipe surface, the magnitude of which is propor-tional to the lateral deflection of the induced currents in thep
20、lane of that surface.3.3.5 configuration datastandardization data and instru-mentation settings for a particular probe stored in a computerfile.3.3.6 data sample ratethe rate at which data is digitizedfor display and recording, in data points per second.3.3.7 longitudinalfollowing from the above def
21、inition, alongitudinal discontinuity is parallel to the pipe axis andtherefore perpendicular to the scan direction.3.3.8 operational standardization blocka reference stan-dard with specified artificial notches, used to confirm theoperation of the system.3.3.9 pinthe male thread in a drillstring conn
22、ection.3.3.10 satellite signalsBx and Bz signals observed whenthe probe passes a discontinuity in an adjacent thread root.3.3.11 surface plotfor use with array probes. This type ofplot has one component of the magnetic field plotted over anarea, typically as a color contour plot or 3-D wire frame pl
23、ot.3.3.12 time base plotsthese plot the relationship betweenBx or Bz values with time.3.3.13 transverseas is normal in drilling, the terms trans-verse and longitudinal are defined in reference to the pipe axis.Therefore, a transverse discontinuity is parallel to the threadand hence to the scan direc
24、tion. This is different to the situationfor weld inspection, covered in Guide E2261.3.3.14 X-Y Plotan X-Y graph with two orthogonal com-ponents of magnetic field plotted against each other.NOTE 1Different equipment manufacturers may use slightly differentterminology. Reference should be made to the
25、equipment manufacturersdocumentation for clarification.4. Summary of Practices4.1 In a basic alternating current field measurement system,a small probe is moved around the thread root. The probecontains an exciter coil, which induces anAC magnetic field inthe material surface aligned to the directio
26、n of the thread root.This, in turn, causes alternating current to flow across thethreads. The depth of penetration of this current varies withmaterial type and frequency but is typically 0.004 in. 0.1 mmdeep in magnetic materials and 0.08 to 0.3 in. 2 to 7 mm deepin non-ferrous materials. Any surfac
27、e breaking discontinuitieswithin a short distance of either side of the scan line at thislocation will interrupt or disturb the flow of the alternatingcurrent. Measurement of the absolute quantities of the twomajor components of the surface magnetic fields (Bx and Bz)determines the severity of the d
28、isturbance (see Fig. 1) and thusthe severity of the discontinuity. Discontinuity sizes, such ascrack length and depth, can be estimated from the values ofthese quantities or the physical locations of key points, or both,selected from the Bx and Bz traces along with the standardiza-tion data and inst
29、rument settings from each individual probe.This discontinuity sizing can be performed automatically usingsystem software. Discontinuities essentially perpendicular tothe thread may be detected (in ferritic metals only) by the fluxleakage effect.4.2 Configuration data is loaded at the start of the ex
30、ami-nation. System sensitivity and operation is verified using anoperation standardization block. System operation is checkedand recorded prior to and at regular intervals during theexamination. This can be accomplished using discontinuity-sizing tables in the system software. Data is recorded in am
31、anner that allows archiving and subsequent recall for eachthread. Evaluation of examination results may be conducted atthe time of examination or at a later date. The examinergenerates an examination report detailing complete results ofthe examination.5. Significance and Use5.1 The purpose of the al
32、ternating current field measure-ment method is to evaluate threads for surface breakingdiscontinuities such as fatigue cracks running along the threadroot. The examination results may then be used to determinethe fate of the tool. This may involve re-examination by analternative technique, immediate
33、 scrapping of the tool, orreworking to remove discontinuities (beyond the scope of thisFIG. 1 Example Bx and Bz Traces as a Probe Passes Over aCrack (The orientation of the traces may differ depending uponthe instrumentation.)E2928/E2928M 172practice). This practice is not intended for the examinati
34、on ofthreads for non-surface breaking discontinuities.6. Basis of Application6.1 Personnel Qualificationif specified in the contractualagreement, personnel performing examinations to this practiceshall be qualified in accordance with a nationally or interna-tionally recognized NDT personnel qualific
35、ation practice orstandard such as ANSI/ASNT-CP-189, SNT-TC-1A, ISO9712, or a similar document and certified by the employer orcertifying agent, as applicable. The practice or standard usedand its applicable revision shall be identified in the contractualagreement between the using parties6.2 Qualifi
36、cation of Nondestructive Evaluation Agenciesifspecified in the contractual agreement, NDT agencies shall bequalified and evaluated as described in Specification E543,with reference to sections on electromagnetic examination. Theapplicable edition of Specification E543 shall be specified inthe contra
37、ctual agreement.7. Job Scope and Requirements7.1 The following items may require agreement by theexamining party and their client and should be specified in thepurchase document or elsewhere:7.1.1 Location and type of threaded component to beexamined, design specifications, degradation history, prev
38、iousnondestructive examination results, maintenance history, pro-cess conditions, and specific types of discontinuities that arerequired to be detected, if known.7.1.2 The maximum recommended probe scan speed is tobe stated by the manufacturer. However, detection of smallerdiscontinuities requires a
39、 slower probe scan speed or cleaningof surface, or both.7.1.3 Size, material grade and type, and configuration ofthreads to be examined.7.1.4 A thread numbering or identification system.7.1.5 Extent of examination, for example: complete orpartial coverage, which threads and to what extent.7.1.6 Type
40、 of alternating current field measurement instru-ment and probe; and description of operations standardizationblock used, including such details as dimensions and material.7.1.7 Required thread cleanliness.7.1.8 Environmental conditions, equipment and prepara-tions that are the responsibility of the
41、 client; common sourcesof noise that may interfere with the examination, such as motordrive for rotary table.7.1.9 Complementary methods or techniques may be usedto obtain additional information.7.1.10 Acceptance criteria to be used in evaluating discon-tinuities.7.1.11 Disposition of examination re
42、cords and referencestandards.7.1.12 Format and outline contents of the examinationreport.8. Interferences8.1 This section describes items and conditions, which maycompromise the alternating current field measurement tech-nique.8.2 Material Properties:8.2.1 Although there are unlikely to be permeabil
43、ity differ-ences in a ferromagnetic material between different parts of athread, if a probe is scanned across a permeability change suchas an area of residual magnetism, this may produce indicationswhich could be similar to those from a discontinuity. Differ-entiation between a discontinuity signal
44、and a permeabilitychange signal can be achieved by comparing scans fromneighboring threads. The signal from a discontinuity will dieaway quickly. If there is no significant change in indicationamplitude two or more threads away along the pipe axis thenthe indication is likely due to the permeability
45、 changes in thecomponent.8.3 Magnetic State:8.3.1 DemagnetizationIt must be ensured that the surfacebeing examined is in a low magnetization state, or that anymagnetization is uniform over the surface. Therefore theprocedure followed with any previous magnetic techniquedeployed must include demagnet
46、ization of the surface, orensuring that connections are magnetically saturated. This isbecause areas of remnant magnetization, particularly where theleg of a magnetic particle examination yoke was sited, canproduce loops in the X-Y plot, which may sometimes beconfused with a discontinuity indication
47、.8.4 Thread Geometry:8.4.1 When a probe scans away from the shoulder of a pinconnection, the Bx indication value will decrease with littlechange in the Bz value. In the representative plot of Fig. 2, thisappears as a drop in the X-Y plot. The Bx indication value willalso decrease as a probe approach
48、es the open end of a thread(pin or box).FIG. 2 Example X-Y Plot Produced by Plotting the Bx (vertical)and Bz (horizontal) Together (The orientation of the plot may dif-fer depending upon the instrumentation.)E2928/E2928M 1738.5 Crack Geometry Effects:8.5.1 Since the effect of a discontinuity on the
49、signals can bedetected some distance away, “satellite” signals are observedas the probe passes one thread (or two threads) away from asufficiently-large discontinuity. The satellite signals will besmaller than the main discontinuity signal, and symmetricallyspaced one thread revolution either side. Care should be takennot to classify these signals as additional discontinuities.8.5.2 A large discontinuity may jump across a thread crownfrom one root to the neighboring one. This causes a sudden risein Bx signal where the discontinuity leave
