1、Designation: E1961 11Standard Practice forMechanized Ultrasonic Testing of Girth Welds Using ZonalDiscrimination with Focused Search Units1This standard is issued under the fixed designation E1961; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers the requirements for mechanizedultrasonic examination of girth welds.
3、 Evaluation is basedupon the results of mechanized ultrasonic examination. Accep-tance criteria are based upon flaw limits defined by anEngineering Critical Assessment (ECA) or other accept/rejectcriteria defined by the Contracting Agency.1.2 This practice shall be applicable to the development ofan
4、 examination procedure agreed upon between the users ofthis practice.1.3 The values stated in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with
5、 its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 The following documents form a part of this practice tothe extent specified herein:2
6、.2 ASTM Standards:2E164 Practice for Contact Ultrasonic Testing of WeldmentsE317 Practice for Evaluating Performance Characteristicsof Ultrasonic Pulse-Echo Testing Instruments and Systemswithout the Use of Electronic Measurement InstrumentsE543 Specification for Agencies Performing Nondestruc-tive
7、TestingE1316 Terminology for Nondestructive Examinations2.3 ASNT Standard:3ASNT Practice SNT-TC-1A Personnel Qualification andCertification in Nondestructive TestingANSI/ASNT-CP-189 Standard for Qualification and Certi-fication of Nondestructive Testing Personnel2.4 AIA Standard:NAS-410 Nondestructi
8、ve Testing Personnel Qualificationand Certification42.5 API Standard:API STD1104 Welding of Pipeline and Related Facilities52.6 CSA Standard:CSA Z-662 Oil and Gas Pipelines Systems63. Terminology3.1 Definitions:3.1.1 Definitions relating to ultrasonic examination, thatappear in Terminology E1316 sha
9、ll apply to the terms used inthis practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 acceptance criteriadefinition of acceptable/rejectable flaws as defined by an Engineering Critical Assess-ment (ECA), such as defined in CSA-Z662 or API 1104, orworkmanship criteria as defined by the
10、contracting agency.3.2.2 contract documentany document specified in thecontract between the contracting agency and contractor, includ-ing the purchase order, specification, drawings or other writtenmaterial.3.2.3 contracting agencya government agency, primecontractor or subcontractor procuring ultra
11、sonic examinationservices.3.2.4 contractorthe nondestructive examination contrac-tor engaged by the contracting agency in work covered by thispractice.3.2.5 mapping type presentationsan ultrasonic image pre-sentation whereby the digitized A-scan signal is represented ascolors or grayscale for amplit
12、ude variation along one axis1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.06 onUltrasonic Method.Current edition approved July 1, 2011. Published July 2011. Originally approvedin 1998. Last previous edit
13、ion approved in 2006 as E1961 - 06. DOI: 10.1520/E1961-11.2For 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.3Av
14、ailable fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.4Available from Aerospace Industries Association of America, Inc. (AIA), 1000Wilson Blvd., Suite 1700,Arlington, VA22209-3928, http:/www.aia-aerospace.org.5A
15、vailable from American Petroleum Institute (API), 1220 L. St., NW, Wash-ington, DC 20005-4070, http:/www.api.org.6Available from Canadian Standards Association (CSA), 5060 Spectrum Way,Mississauga, ON L4W 5N6, Canada, http:/www.csa.ca.1*A Summary of Changes section appears at the end of this standar
16、d.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.representing time of flight and the other axis is the samplingposition, or the distance along the weld.3.2.6 operator(s)the term “operator(s)” as used in thispractice shall mean the op
17、erator(s) of ultrasonic equipmentwho is (are) certified according to the requirements in 5.2 andat a level deemed acceptable to the contracting agency.4. Significance and Use4.1 This practice is intended primarily for the mechanizedultrasonic examination of pipe girth welds used in the con-struction
18、 of gas and oil pipelines. This practice, with appropri-ate modifications due to changes in weld profile, may also beused to examine repaired welds. Manual techniques such asdescribed in Practice E164 may also be used to examineproduction or repaired welds. This practice, with appropriatemodificatio
19、ns, may also be used to examine other forms of buttwelds including long seams.4.2 Techniques used are to be based on zonal discriminationwhereby the weld is divided into approximately equal verticalexamination sections (zones) each being assessed by a pair ofultrasonic search units. See Fig. 1 for t
20、ypical zones.4.3 Thicknesses of material examined are normally 7 to 25mm (0.28 to 1.00 in.) and pipe diameters 15 cm (6.0 in.) andgreater but this standard may apply to other thicknesses anddiameters if the techniques can be proven to provide therequired zonal discrimination.4.4 Examination zones ar
21、e typically 2 to 3 mm (0.08 to 0.12in.) in height. For most applications this will require the use ofcontact focused search units to avoid interfering signals origi-nating from off-axis geometric reflectors and to avoid exces-sive overlap with adjacent zones.5. Basis of Application5.1 The following
22、items are subject to contractual agree-ment between the parties using or referencing this standard.5.2 Personnel Qualification:5.2.1 If specified in the contractual agreement, personnelperforming examinations to this standard shall be qualified inaccordance with a nationally or internationally recog
23、nizedNDT personnel qualification practice or standard such asANSI/ASNT-CP-189, SNT-TC-1A, NAS-410, or a similardocument and certified by the employer or certifying agency,as applicable. The practice or standard used and its applicablerevision shall be identified in the contractual agreement be-tween
24、 the using parties.5.3 Qualification of Nondestructive AgenciesIf specifiedin the contractual agreement, NDT agencies shall be qualifiedand evaluated as described in Practice E543. The applicableedition of Practice E543 shall be specified in the contractualagreement.5.4 Procedures and TechniquesThe
25、procedures and tech-niques to be used shall be as specified in the contractualagreement.5.5 Surface PreparationThe pre-examination surfacepreparation criteria shall be in accordance with 10.2, unlessotherwise specified.5.6 Timing of ExaminationThe timing of examinationshall be in accordance with 10.
26、3, unless otherwise specified.5.7 Extent of ExaminationThe extent of examination shallbe in accordance with Section 8, unless otherwise specified.5.8 Reporting Criteria/Acceptance CriteriaReporting cri-teria for the examination results shall be in accordance withSection 11, unless otherwise specifie
27、d. Since acceptance crite-ria are not specified in this standard, they shall be specified inthe contractual agreement.5.9 Reexamination of Repaired/Reworked ItemsReexamination of repaired/reworked items is not addressed inthis standard and if required shall be specified in the contrac-tual agreement
28、.FIG. 1 Schematic Representation of Weld Zones and DiscontinuitiesE1961 1126. Examination Methods6.1 Visual ExaminationAll welds shall be visually exam-ined after completion and assessed in accordance with therequirements of surface conditions for ultrasonic examination.6.2 All bevels shall be exami
29、ned immediately after machin-ing to ensure compliance with the applicable welding proce-dure. This examination should be combined with scribing thereference line as described in 10.4.6.3 Any items of non-compliance shall be referred to thecontracting agency representative for corrective action.6.4 U
30、ltrasonic ExaminationAll girth welds identified formechanized ultrasonic examination shall be examined for100 % of their circumference and assessed in accordance withthe contracting agencys acceptance criteria. Examinationshould be conducted in accordance with procedures approvedby the contracting a
31、gency.7. Ultrasonic Equipment7.1 Ultrasonic SystemThe system shall provide an ad-equate number of examination channels to ensure the completevolumetric examination of the weld through thickness in onecircumferential scan. The instrument shall provide a linear “A”scan presentation for each channel se
32、lected. The examinationchannels will allow the volume of the weld scanned to beassessed in accordance with the examination zones as typicallydefined in Fig. 1. Instrument linearity shall be determinedaccording to the procedures detailed in Practice E317, withinsix months of the intended end use date
33、. The contractor shallretain a copy of the calibration certificate. Instrument linearityshall be such that the accuracy of any indicated amplitude iswithin 5 % of the actual full scale amplitude. This shall applyto both linear and logarithmic amplifiers. Each examinationchannel shall be selective fo
34、r: pulse-echo or through-transmission mode, gate position and length for a minimum oftwo gates, and gain. Recording thresholds shall be selectable todisplay signals between 0 and 100 % of full screen height forsimple amplitude and transit time recording and shall be from0 to 100 % for B-scan or “map
35、ping” type recording of data.Two recordable signal outputs per gate shall be available, beingeither analog or digital and representative of signal height andtime of flight. These will be suitable for recording on amulti-channel recorder or computer data acquisition softwaredisplay.7.2 Recording Syst
36、em:7.2.1 A distance measuring circuit or device suitable forconnection to the recorder or acquisition system shall providea means of electronically determining circumferential welddistance to an accuracy of typically 61 cm (0.4 in.) or better,as required by the contracting agency, over the circumfer
37、enceof the weld (an optical encoder is typically used for suchdistance measurement). Programmed scan lengths shall besufficient to ensure all probes will travel the maximum circum-ferential distance required for a pipe having a diameter with themaximum tolerance allowed by the contracting agencys sp
38、eci-fication. For equipment with encoders traveling on a track orwelding guide-band a correction factor will be incorporated toensure the circumferential distance recorded on the chartcorresponds to the search unit position on the pipe outersurface. The recording or marking system shall clearly indi
39、catethe location of discontinuities relative to the marked startingposition of the scan, with a 61 cm (0.4 in.) accuracy. Thereshall be recordings from each search unit for weld discontinui-ties and confirmation of the acoustic coupling arranged on thechart or display in a manner acceptable to the c
40、ontractingagency.7.2.2 B-scan or other form of “mapping” displays will beused for volumetric flaw detection and characterizations andTime of Flight Diffraction (TOFD) techniques may be added toimprove characterization and sizing. TOFD techniques mayaugment pulse-echo techniques but shall not replace
41、 pulse-echo techniques.7.2.3 Where TOFD techniques are employed the recordingsystem shall be capable of a 256-level grayscale display and becapable of recording full R-F wave forms for the TOFD searchunit pairs.7.3 CouplingThe coupling shall be obtained by using amedium suitable for the purpose. An
42、environmentally safewetting agent may be required to enhance acoustic coupling.No residue should remain on the pipe surface after the liquidhas evaporated. For examination where ambient temperaturesare below 0C (32F) a methyl alcohol washer fluid or a similarmedium may be used. This liquid medium ma
43、y be recoveredand filtered for re-use. For examination where pipe cool-downmay be required after welding, water spray or other agents maybe used with contracting agency approval.7.4 Search Units:7.4.1 Each search unit shall be marked with a method toidentify the manufacturers name, search unit type,
44、 exit point,incident beam angle or refracted beam angle for a specificwedge/steel velocity ratio, frequency, and crystal size.77.4.2 The search unit array design shall be specific to theproject where the examination is to be performed.7.4.3 All search units shall be contoured to match thecurvature o
45、f the pipe surface.7.5 Reference StandardsReference standards shall beused to establish sensitivity and qualify the examination systemfor field examination and to monitor the systems performanceon an ongoing basis. Reference standards shall be manufac-tured from a section of unflawed project-specifi
46、c line pipesupplied by the contracting agency. The contracting agencywill provide the contractor with details of project-specific weldgeometries and the reference reflectors required in specificareas. The contractor shall then provide a reference standarddesign that must be submitted to the contract
47、ing agency forapproval before manufacturing. No design changes to thereference standard shall be made without prior approval of thecontracting agency.AnnexA3 provides an example of a typicalreference standard.7.6 Ultrasonic Examination ProcedureThe contractorshall provide a procedure that will provi
48、de examination criteriafor the ultrasonic examination of the weld in a single pass. Itmust allow for characteristic Hi/Lo fit-ups (edge misalign-ment), weld shrinkage and be pipe-size specific. Procedures7For phased array and EMAT probes, not all of the listed items may beapplicable.E1961 113submitt
49、ed will allow zonal flaw characterization that permitsuse of the contracting agencys engineering critical assessmentacceptance criteria. It shall include but not be limited todescribing the following requirements:7.6.1 The mechanized variable speed scanner mountable onmechanical welding bands or other tracking mechanism,7.6.2 The encoder capable of accurately indicating any flawlocation about the girth weld,7.6.3 Independently loaded ultrasonic search units mountedin an array that provides independent examination of the weldfrom both sides,7.6.4 Provis
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