1、Designation: E 1961 06Standard Practice forMechanized Ultrasonic Testing of Girth Welds Using ZonalDiscrimination with Focused Search Units1This standard is issued under the fixed designation E 1961; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase 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.1. Scope1.1 This practice covers the requirements for mechanizedultrasonic examination of girth weld
3、s. 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 of
4、an 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 brackets 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:2E 164 Practice for Ultrasonic Contact Examination of Weld-mentsE 317 Practice for Evaluating Performance Characteristicsof Ultrasonic Pulse-Echo Testing Instruments and Systemswithout the Use of Electronic Measurement InstrumentsE 1316 Terminology for Nondestructive Examinations2.3
7、 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 Military Standard:MIL-Std-410 Nondestructive Testing Personnel Qualifica-tion and Certificat
8、ion42.5 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 E 1316 shall apply to the terms used inthis practice.3.2
9、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 contracting agency.3.2.2 contract documentany do
10、cument 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 ultrasonic examinationservices.3.2.4 contractorthe no
11、ndestructive 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 amplitude variation along one axisrepresenting time of
12、 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 operator(s) of ultrasonic equipment1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the di
13、rect responsibility of Subcommittee E07.06 onUltrasonic Method.Current edition approved Dec. 1, 2006. Published January 2007. Originallyapproved in 1998. Last previous edition approved in 2003 as E 1961 - 98(2003)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM
14、 Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from TheAmerican Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518.4Available from
15、 Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS5Available from American Petroleum Institute, 1220 L Street, Northwest,Washington, DC 20005.6Available from Canadian Standards Association, 178 Rexdale Boulevard,Etobicoke, Ontario, Can
16、ada M9W 1R3.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.who is (are) certified according to the requirements in 6.6 andat a level deemed acceptable to the contracting agency.4. Significance and Use4.1 This practice is intended pr
17、imarily for the mechanizedultrasonic examination of pipe girth welds used in the con-struction 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 E 164 may
18、also be used to examineproduction or repaired welds. This practice, with appropriatemodifications, 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 verticalexamina
19、tion sections (zones) each being assessed by a pair ofultrasonic search units. See Fig. 1 for typical 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 te
20、chniques can be proven to provide therequired zonal discrimination.4.4 Examination zones are 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
21、to avoid exces-sive overlap with adjacent zones.5. Examination Methods5.1 Visual ExaminationAll welds shall be visually exam-ined after completion and assessed in accordance with therequirements of surface conditions for ultrasonic examination.5.1.1 All bevels shall be examined immediately after ma-
22、chining to ensure compliance with the applicable weldingprocedure. This examination should be combined with scribingthe reference line as described in 9.3.5.1.2 Any items of non-compliance shall be referred to thecontracting agency representative for corrective action.5.2 Ultrasonic ExaminationAll g
23、irth 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 agency.6. Ultrasonic Equipm
24、ent6.1 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 selected. The examinationcha
25、nnels 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 E 317, withinsix months of the intended end use date. The contractor shallret
26、ain 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 for: pulse-echo or through-
27、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 “mapping” type recording of d
28、ata.Two recordable signal outputs per gate shall be available, beingeither analog or digital and representative of signal height andFIG. 1 Schematic Representation of Weld Zones and DiscontinuitiesE1961062time of flight. These will be suitable for recording on amulti-channel recorder or computer dat
29、a acquisition softwaredisplay.6.2 Recording System:6.2.1 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
30、 by the contracting agency, over the circumferenceof 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 t
31、olerance allowed by the contracting agencys speci-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
32、recording or marking system shall clearly indicatethe 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 thechar
33、t or display in a manner acceptable to the contractingagency.6.2.2 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
34、 pulse-echo techniques but shall not replace pulse-echo techniques.6.2.3 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.6.3 CouplingThe coupling shall be obtained by
35、 using amedium suitable for the purpose. An 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 simila
36、rmedium may be used. This liquid medium may 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.6.4 Search Units:6.4.1 Each search unit shall be marked with a method toidentify
37、 the manufacturers name, search unit type, exit point,incident beam angle or refracted beam angle for a specificwedge/steel velocity ratio, frequency, and crystal size.76.4.2 The search unit array design shall be specific to theproject where the examination is to be performed.6.4.3 All search units
38、shall be contoured to match thecurvature of the pipe surface.6.5 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
39、from a section of unflawed project-specific 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 standarddes
40、ign that must be submitted to the contracting 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.6.6 Personnel QualificationIf specified in the co
41、ntractualagreement, personnel performing examinations to this practiceshall be qualified in accordance with a nationally recognizedNDT personnel qualification practice or standard such asANSI/ASNT-CP-189, SNT-TC-1A, MIL-STD-410, or a simi-lar document and certified by the employer or certifyingagenc
42、y as applicable. The practice or standard used and itsapplicable version shall be identified in the contractual agree-ment between the using parties.6.7 Ultrasonic Examination ProcedureThe contractorshall provide a procedure that will provide examination criteriafor the ultrasonic examination of the
43、 weld in a single pass. Itmust allow for characteristic Hi/Lo fit-ups (edge misalign-ment), weld shrinkage and be pipe-size specific. Proceduressubmitted will allow zonal flaw characterization that permitsuse of the contracting agencys engineering critical assessmentacceptance criteria. It shall inc
44、lude but not be limited todescribing the following requirements:6.7.1 The mechanized variable speed scanner mountable onmechanical welding bands or other tracking mechanism,6.7.2 The encoder capable of accurately indicating any flawlocation about the girth weld,6.7.3 Independently loaded ultrasonic
45、search units mountedin an array that provides independent examination of the weldfrom both sides,6.7.4 Provisions for adjusting and maintaining the align-ment of these search units,6.7.5 Provisions for recording the continuity of the cou-pling,6.7.6 Provisions for ensuring the mechanical reliability
46、 ofthe equipment,6.7.7 A technique summary stating beam angles, wavetypes, search unit frequencies, beam sizes and profiles withsketches for each geometry to be examined,6.7.8 Record analog or digital signals from the multi-channels to a common distance of rotation,6.7.9 Provide permanent copy of th
47、e scans in an easilyinterpretable format to meet archival and audit needs,6.7.10 Provide construction and accuracy details of thereference standard,6.7.11 Provide the standardization procedures to be used inthe field, and6.7.12 Standardization checks shall be established and veri-fied on a time or w
48、eld cycle defined by the contracting agency.7For phased array and EMAT probes, not all of the listed items may beapplicable.E1961063System performance between standardization checks shall becontinually monitored for degradation.7. Ultrasonic Examination Set-Up7.1 Search Unit Positioning and Primary
49、ReferenceSensitivityThe system shall be optimized for field examina-tion using the reference standard. Each search unit shall bepositioned at its operating distance from the simulated weldcenterline on the reference standard and adjusted to provide apeak signal from its target reference reflector in the searchunits examination zone. The peak signal response shall beadjusted to 80 % full-screen height (FSH) for each channel.The gain level determined for each search unit shall be theprimary reference.7.2 Gate Settings:7.2.1 Fusion-Zone Search UnitsUsin
