1、Designation: E2863 11Standard Practice forAcoustic Emission Examination of Welded Steel SpherePressure Vessels Using Thermal Pressurization1This standard is issued under the fixed designation E2863; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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. Scope1.1 This practice is commonly used for periodic inspectionand testing of welded steel gaseous
3、spheres (bottles) is theacoustic emission (AE) method. AE is used in place ofhydrostatic volumetric expansion testing. The periodic inspec-tion and testing of bottles by AE testing is achieved withoutdepressurization or contamination as is required for hydrostaticvolumetric expansion testing.1.2 The
4、 required test pressurization is achieved by heatingthe bottle in an industrial oven designed for this purpose. Themaximum temperature needed to achieve the AE test pressureis #250F (121C).1.3 AE monitoring of the bottle is performed with multiplesensors during the thermal pressurization.1.4 This pr
5、actice was developed for periodic inspection andtesting of pressure vessels containing Halon (UN 1044), whichis commonly used aboard commercial aircraft for fire suppres-sion. In commercial aircraft, these bottles are hermeticallysealed by welding in the fill port. Exit ports are opened byexplosivel
6、y activated burst disks. The usage of these pressurevessels in transportation is regulated under US Department ofTransportation (DOT), Code of Federal Regulations CFR 49.ADOT special permit authorizes the use of AE testing forperiodic inspection and testing in place of volumetric expan-sion and visu
7、al inspection. These bottles are spherical withdiameters ranging from 5 to 16 in. (127 to 406 mm).1.5 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are mathemati-cal conversions to SI units that are provided for informationonly and are not c
8、onsidered 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 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to
9、use. Specific precau-tionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing Nondestruc-tive TestingE650 Guide for Mounting Piezoelectric Acoustic EmissionSensorsE976 Guide for Determining the Reproducibility of Acous-tic Emissi
10、on Sensor ResponseE1316 Terminology for Nondestructive ExaminationsE2075 Practice for Verifying the Consistency of AE-SensorResponse Using an Acrylic RodE2374 Guide for Acoustic Emission System PerformanceVerification2.2 ASNT Standards:3SNT-TC-1A Recommended Practice for NondestructiveTesting Person
11、nel Qualification and CertificationANSI/ASNT CP-189 Standard for Qualification and Certi-fication of Nondestructive Testing Personnel2.3 Code of Federal Regulations:Section 49 Code of Federal Regulations, Hazardous Mate-rials Regulations of the Department of Transportation,Paragraphs 173.34, 173.301
12、, 178.36, 178.37, and 178.4542.4 Compressed Gas Association Standard:Pamphlet C-5 Service Life, Seamless High Pressure Cylin-ders53. Terminology3.1 DefinitionsSee Terminology E1316 for general termi-nology applicable to this test method.3.2 Definitions of Terms Specific to This Standard:3.2.1 marked
13、 service pressurepressure for which a vesselis rated. Normally, this value is stamped on the vessel1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.04 onAcoustic Emission Method.Current edition approved Dec
14、. 15, 2011. Published January 2012. DOI:10.1520/E2863-11.2For 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.3Ava
15、ilable fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.4Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo
16、.gov.5Available from Compressed Gas Association (CGA), 4221 Walney Rd., 5thFloor, Chantilly, VA 20151-2923, http:/.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Practice4.1 Acoustic emission (AE) sensors are mounted o
17、n apressure vessel, and emission is monitored while the pressurevessel is heated to a pre-determined temperature for achievingthe desired AE test pressure. The elevated temperature resultsin expansion of the gaseous component and causes the increaseof the internal pressure. This increasing pressure
18、applies stressin the pressure vessel wall. The ultimate pressure is calculatedbased on the contents of the pressure vessel (bottle) andmaximum operating temperature that bottle has been exposed(for example, during fast filling).4.2 Sensors are mounted in at least six positions on thevessel and are c
19、onnected to an acoustic emission signalprocessor. The signal processor uses measured times of arrivalof emission bursts to determine the location of emissionsources on the vessels surface. The locations are continuallychecked for clustering. If a cluster grows large enough (refer toAppendix X1), and
20、/or its behavior with increasing temperature(pressure) departs significantly from a linear increase (refer toAppendix X1), the vessel is declared unsatisfactory for con-tinued service.4.3 Bottles that fail this AE examination procedure cannotbe subjected to a secondary examination (for example, hydr
21、o-static volumetric expansion test) because the AE test is themore sensitive test. When a bottle has been rejected by an AEtest, it should be rendered unserviceable.4.4 To repeat a valid AE examination on a bottle, aminimum of six months interval shall be required to the bottleafter its highest prev
22、ious internal pressure.5. Significance and Use5.1 Because of safety considerations, regulatory agencies(for example, U.S. Department of Transportation) requireperiodic tests of pressurized vessels used in commercialaviation. (see Section 49, Code of Federal Regulations). AEesting has become accepted
23、 as an alternative to the commonhydrostatic proof test.5.2 An AE test should not be conducted for a period of oneyear after a common hydrostatic test. See Note 1.NOTE 1The Kaiser effect relates to the irreversibility of acousticemission which results in decreased emission during a second pressuriza-
24、tion. Common hydrostatic tests use a relatively high test pressure (200 %of normal service pressure). (See Section 49, Code of Federal Regula-tions.) If an AE test is performed too soon after such a hydrostaticpressurization, the AE results will be insensitive below the previousmaximum test pressure
25、.5.3 Acoustic Emission is produced when an increasingstress level in a material causes crack growth in the material orstress related effects in a corroded surface (for example, crackgrowth in or between metal crystallites or spalling and crackingof oxides and other corrosion products).5.4 While back
26、ground noise may distort AE data or renderit useless, heating the vessels inside an industrial oven is analmost noise free method of pressurization. Further, sourcelocation algorithms using over-determined data sets will oftenallow valid tests in the presence of otherwise interfering noisesources. B
27、ackground noise should be reduced or controlled butthe sudden occurrence of such noise does not necessarilyinvalidate a test.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 Qualification:6.2.1 I
28、f specified in the contractual agreement, personnelperforming examinations to this standard shall be qualified inaccordance with a nationally or internationally recognizedNDT personnel qualification practice or standard such asANSI/ASNT-CP-189, SNT-TC-1A, NAS-410, or a similardocumented and certifie
29、d 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 the using parties.6.2.2 The NDT personnel shall be qualified in accordancewith a nationally recognized NDT personnel qualificationp
30、ractice or standard such as ANSI/ASNT CP-189, SNT-TC-1A, or a similar document. The practice or standard used andits applicable revision shall be specified in the contractualagreement between the using parties.6.3 Qualification of Nondestructive Testing AgenciesIfspecified in the contractual agreeme
31、nt, NDT agencies shall bequalified and evaluated as described in Specification E543. Theapplicable edition of Specification E543 shall be specified inthe contractual agreement.6.4 Procedures and TechniquesThe procedures and tech-niques to be utilized shall be as specified in the contractualagreement
32、.6.5 Surface PreparationThe pre-examination surfacereparation criteria shall be in accordance with 10.2.1, unlessotherwise specified.6.6 Reporting Criteria/Acceptance CriteriaReporting cri-teria for the examination results shall be in accordance withAppendix X1 unless otherwise specified.7. Apparatu
33、s7.1 Essential features of the apparatus required for thispractice are provided in Fig. 1. Full specifications are in AnnexA1.7.2 A couplant can be used between the sensors and vesselwall. The small diameter of the sensor and significant contactpressure reduces the requirement for a couplant, but it
34、 is oftenuseful when positioning a vessel in the test frame to avoidinterfering features on its surface or when the first ASTcoupling test has failed.7.3 AE Sensors are held in place by means of spring-loadedrods mounted to the test frame.7.4 The AE sensors are continuously monitored throughoutthe p
35、ressurization.7.5 A preamplifier for each sensor is located outside theoven. The sensor cable length must not exceed 6 ft (2 m).7.6 The signal processor is a computerized instrument withindependent channels that filter, measure, and convert analoginformation into digital form for analysis, display a
36、nd perma-nent storage. A signal processor must have sufficient speed andcapacity to independently process data from all sensors simul-taneously. The signal processor must be programed to locatethe sources on the surfaces of the vessel and to detect clusteringof the sources. The instrument must be ca
37、pable of reading theE2863 112vessel temperature and controlling the industrial oven. It mustalso conduct and interpret AST tests both before and after thethermal pressurization.7.6.1 Hard copy capability should be available from aprinter or equivalent device.8. Safety Precautions8.1 This examination
38、 involves pressurization of sealed ves-sels by heating. When a significant defect is detected, there isno method of decreasing the internal pressure except cooling ofthe vessel. It is imperative that the heating cease as soon as asignificant defect is identified. This requires that theAE systemhave
39、complete control over the examination, including the preand post-examination system performance verification; theoven heaters; detecting, identifying and classifying defects andthe determination of when the defect behavior requires the testto be stopped, decreasing the possibility of an explosion. T
40、heoperator has no control over the carrying out of the test,including analysis and grading of defects or when to stop thetest for safety reasons.8.2 Maximum temperature of the ovens heating elementsurface must remain below 800F (427C). This will preventthermal decomposition of the HALON 1301 into to
41、xic byprod-ucts in the event of an accidental release.8.3 HALON 1301, itself, has low toxicity but a rapid releaseof pressure could rupture the oven and/or present an asphyxi-ation hazard in a small enclosed region.9. Calibration and Verification9.1 Annual calibration and verification of AE sensors,
42、preamplifiers, signal processor (particularly the signal proces-sor time reference), and AE electronic waveform generator,should be performed. Equipment should be adjusted so that itFIG. 1 AE System Block DiagramFIG. 2 AE Sensor Holding Fixture (sensors on the head of thespring loaded rods)E2863 113
43、conforms to equipment manufacturers specifications. Instru-ments used for calibrations must have current accuracy certi-fication that is traceable to the National Institute for Standardsand Technology (NIST).9.2 Routine electronic evaluations must be performedwithin 30 days prior to a test or any ti
44、me there is concern aboutsignal processor performance. An AE electronic waveformgenerator should be used in making evaluations. Each signalprocessor channel must respond with peak amplitude readingwithin 62 dB of the electronic waveform generator output.9.3 Routine sensor performance verification mu
45、st be per-formed within 30 days prior to the test date and any time thereis concern for sensor performance. A procedure for sensorperformance verification is found in Practice E2075.9.4 A system performance check must be conducted as partof the AE test immediately before and after thermal pressur-iz
46、ation. A performance check uses a feature of the AE systemknown as “Auto Sensor Test (AST).” When initiated, the ASTfeature injects a voltage pulse into one sensor at a time. Theresulting stress wave travels from the pulsing sensor to theremaining sensors, through the vessel metal surface and thepea
47、k amplitude of each is recorded. During pre-examinationAST, any sensor, in which the average of the amplitudesdetected by a sensor falls outside +6 dB of the average of theentire set, will cause the AST test to fail. When the pre-examination AST is failed, the sensors must be checked andreseated. On
48、ly when all sensors are within +6 dB of theaverage can the examination begin. If the post examinationAST fails, the senior engineer in charge of the system mustexamine the stored data to determine whether the AE exami-nation is valid.10. Procedure10.1 The initiation and completion of the examination
49、procedure involves several steps which must be completed bythe operator. The actual heating of the vessel is automated andunder the control of the AE system. The steps which must beconducted by the operator and the function of the automatedAE system follow:10.2 Pre-Examination Operator Procedure:10.2.1 Visually examine the exterior surfaces of the vessel.Note observations in test report.10.2.2 Note pertinent information from the vessel manufac-turers stamping (SN, etc) and record in report.10.2.3 Adjust frame for correct bottle size if necessary.10.2.4
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