1、Designation: E2984/E2984M 14Standard Practice forAcoustic Emission Examination of High Pressure, LowCarbon, Forged Piping using Controlled HydrostaticPressurization1This standard is issued under the fixed designation E2984/E2984M; the number immediately following the designation indicates the yearof
2、 original adoption or, in 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 In the preferred embodiment, this practice examinesimmerse
3、d low carbon, forged piping being immersed in a watertank with the acoustic sensors permanently mounted on thetank walls rather than temporarily on the part itself. The pipesare monitored while being internally loaded (stressed) byhydrostatic means up to 1000 bar.1.2 This practice examines either an
4、 immersed pipe, ornon-immersed pipe being stressed by internal hydrostaticmeans to create acoustic emissions when cracks are present.However, the non-immersed method is time consuming, requir-ing placement and removal of sensors for each pipe inspected,while the immersed method has sensors permanent
5、ly mounted,providing consistent sensor coupling to the tank-eliminatingreinstallation. The non-immersed method is not recommendedfor the specified reasons and only the immersed method will bediscussed throughout the remainder of the standard. This issimilar to pressure vessel testing described in Pr
6、actice E569,but uses hydrostatic means not included in that standard.1.3 This Acoustic Emission (AE) method addresses exami-nation for monitoring low carbon, forged piping systems beinginternally loaded (stressed) by hydrostatic means up to 1000bar 15,000 psi while being immersed in a water bath tof
7、acilitate sensor coupling.1.4 The basic functions of an AE monitoring system are todetect, locate, and classify emission sources. Other methods ofnondestructive testing (NDT) may be used to further evaluatethe significance of acoustic emission sources.1.5 This practice can be used to replace visual
8、methods,which are unreliable and have significant safety risks.1.6 This practice describes procedures to install and monitoracoustic emission resulting from local anomalies stimulated bycontrolled hydrostatic pressure.1.7 Other methods of nondestructive testing (NDT) may beused to further evaluate t
9、he significance of acoustic emissionsources.1.8 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the tw
10、o systems may result in non-conformancewith the standard.1.9 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-bili
11、ty of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing NondestructiveTestingE569 Practice for Acoustic Emission Monitoring of Struc-tures During Controlled StimulationE650 Guide for Mounting Piezoelectric Acoustic EmissionSenso
12、rsE750 Practice for Characterizing Acoustic Emission Instru-mentationE976 Guide for Determining the Reproducibility ofAcousticEmission Sensor ResponseE1316 Terminology for Nondestructive ExaminationsE2374 Guide for Acoustic Emission System PerformanceVerification2.2 Other Referenced DocumentsANSI/AS
13、NT CP-189 Standard for Qualification and Certifi-cation of Nondestructive Testing Personnel31This test method is under the jurisdiction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.04 onAcoustic Emission Method.Current edition approved Oct. 1, 2
14、014. Published October 2014. DOI: 10.1520/E2984_E2984M-14.2For 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
15、ailable from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1NAS-410 NDT Certification4SNT-TC-1A Personnel Qualification an
16、d Certification inNondestructive Testing53. Terminology3.1 DefinitionsDefinitions of terms relating to acousticemission may be found in Section B of Terminology E1316.3.2 Definitions of Terms Specific to This Standard:3.2.1 AE activitythe presence of acoustic emission duringan examination.3.2.2 acti
17、ve sourceone which exhibits increasing cumula-tive AE activity with increasing or constant stimulus.3.2.3 critical sourceis where the event energy rate ex-ceeds a baseline established from known good parts.3.2.4 critically intense sourceone in which the AE sourceintensity consistently increases with
18、 increasing stimulus orwith time under constant stimulus.3.2.5 hydrostatic stimulationapplies stress internally to apressure vessel stimulating any incipient defects to be inmotion yielding stress or strain waves.4. Summary of Practice4.1 Acoustic emission examination of a structure usuallyrequires
19、application of a mechanical or thermal stimulus toproduce changes in the stresses in the structure. In thisapplication, the use of internal hydrostatic pressure, over anappropriate range, stimulates changes in the stresses in thestructure. During this stimulation, AE from discontinuities(such as cra
20、cks, corrosion and inclusions), or from otheracoustic sources (such as leaks or structural motion) can bedetected by an AE instrument, using sensors which, whenstimulated by stress waves, generate electrical signals.4.2 In addition to immediate, real time, evaluation of theemissions detected during
21、the application of the stimulus, apermanent record of the number and location of emittingsources and the relative amount of AE detected from eachsource provides a basis for comparison with sources detectedduring the examination and during subsequent stimulation.This may be used to discriminate betwe
22、en AE events emittingfrom corrosion and those from the more serious cracks.5. Significance and Use5.1 High pressure fluids being pumped in all oil fieldapplications often stress iron pipes where subsequent failurecan lead to injury to personnel or equipment. These forgingsare typically constructed f
23、rom 4700 series low carbon steelwith a wall thickness in excess of 1.25 cm 0.5 in., dependenton the manufacturers specification. The standard method tocertify that these iron segments can withstand operationalpressures is to perform dye penetrant (PT) or magnetic particlepenetrant (MT) tests, or bot
24、h, to reveal defects (cracks andcorrosion). As these methods are subject to interpretation bythe human eye, it is desirable to employ a technique wherebya sensor based system can provide a signal to either pass or failthe test object. To that end, the acoustic emission (AE) methodprovides the requis
25、ite data from which acceptance/rejectioncan be made by a computer, taking the human out of the loop,providing that a human has correctly programmed the accep-tance criteria. Most of these pipe segments are not linear, thusa 3D defect location method is desirable. The 3D sourceindication represents t
26、he spatial location of the defect withoutregard to its orientation, recognizing the source location is onlyapproximate due to sound propagation through the part andwater bath.5.2 The immersed 3D approach is found to be preferabledue to the large number of parts to be examined. The 3Dsystem is easily
27、 replicated and standardized in that all sensorlocations are fixed to the exterior of the fluid bath. Multipleparts may be easily placed into an assembly, allowing all to beexamined in a single test, thus accelerating throughput. Attach-ing a minimum of eight AE sensors to the tank enhances theproba
28、bility that a sufficient number of AE hits in an event willoccur, allowing for an approximate location determination.When an indication of a defect is observed, the subject part isidentified by the spatial location allowing it to be removed forfurther examination, or rejected for service. An immerse
29、d testconfiguration is shown in Fig. 1a and b.5.3 The non-immersed examination is equally effective indetecting defects, but requires more time to assemble in thatsensors must be attached to the part for each examination.Moreover, the fluid fill and air purge times are much longerthan in the immerse
30、d bath immersion. The non-immersed test4Available from Aerospace Industries Association of America, Inc. (AIA), 1000Wilson Blvd., Suite 1700,Arlington, VA22209-3928, http:/www.aia-aerospace.org.5Available fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Colu
31、mbus, OH 43228-0518, http:/www.asnt.org.FIG. 1 (a) Immersion bath with permanently attached AE sensorson exterior (circles)FIG. 1 (b) photo of part under test (continued)E2984/E2984M 142layout and photo are shown in Fig. 2a and b. Note the sensorsare indicated with the symbol x.6. Basis of Applicati
32、on6.1 The following items are subject to contractual agree-ment between the parties using or referencing this practice.6.2 Personnel Qualification6.2.1 If specified in the contractual agreement, personnelperforming examinations to this standard shall be qualified inaccordance with a nationally and i
33、nternationally recognizedNDT personnel qualification practice or standard such asANSI/ASNT CP-189, SNT-TC-1A, NAS-410, or similar asapplicable. The practice or standard used and its applicablerevision shall be identified in the contractual agreement be-tween the using parties.6.3 Qualification of No
34、ndestructive Testing AgenciesIfspecified in the contractual agreement, NDT agencies shall bequalified and evaluated as described in Practice E543. Theapplicable edition of Practice E543 shall be specified in thecontractual agreement.6.4 Timing of ExaminationThe timing of the examinationshall be in a
35、ccordance with a contractual agreement or with anestablished internal procedure.6.5 Extent of ExaminationThis application requires sen-sor(s) placement such that the location where an AE eventoccurs can be reliably detected.6.6 Reporting Criteria/AcceptanceReporting criteria forthe examination resul
36、ts shall be in accordance with Sections11, 12, and 13.6.7 Reexamination of Repaired/Reworked ItemsReexamination of repaired or reworked items is not addressedin this standard and if required shall be specified in acontractual agreement.7. Examination Preparation7.1 Before the examination begins, mak
37、e the followingpreparations for AE monitoring:7.1.1 Sensor requirementsConsideration should be givento the fact that multiple pieces of treating iron will be testedsimultaneously. The type, number, and placement of sensors iscritical in that source location will be used to determine whichpieces are
38、emitting during a hydrotest. Three dimensionalsource location is ideal for this application if used properly.7.1.1.1 This requires knowledge of materials and physicalcharacteristics of the structure being tested as well as theliquid-filled container in which they are tested. It also requiresknowledg
39、e of wave propagation through a liquid as well as theinstrumentation used to collect and process these waves.Knowledge of overdetermined source location is also helpful.7.1.1.2 This determination is also dependent upon the re-quired precision and the accuracy of examination. It is impor-tant to use
40、an appropriate number of sensors to providesufficiently accurate 3D source location to distinguish whichpiece of iron is generating significant AE.7.1.1.3 No fewer than eight sensors are desirable for animmersion tank that is 10 ft. long by 5 ft. wide by 5 ft. deep.7.1.1.4 Tanks with dimensions grea
41、ter than these (for ac-commodating multiple pieces of treating iron) will requiremore sensors to instrument.7.1.2 The immersion tank shell (walls) shall be constructedfrom stainless steel to avoid corrosion. This allows for apermanent attachment of all AE sensors defining a stable 3Dlocation geometr
42、y. The water holding tank shall be no smallerthan 400 cm 13 ft. long by 150 cm 5 ft. wide by 90 cm 3ft. tall, with 25 cm 10 in. legs and levelers to raise the heightto be a comfortable working height and accommodate a rollunder crane for loading and unloading pipes. These dimensionsallow the loading
43、 of multiple components for a simultaneousexamination. The water bath is specified to be distilled with acorrosion inhibitor added.7.1.3 An appropriateAE sensor with a frequency range from150 to 450 kHz shall be employed to avoid ambient noisesources.7.1.4 Establish communications between the contro
44、l pointfor the application of the stimulus and the AE examinationcontrol center.7.1.5 Provide a means for continuously recording a measureof the stimulus.7.1.6 Identify potential sources of extraneous acousticnoise, such as vibration, friction, and fluid flow. Such sourcesFIG. 2 (a) is the layout, w
45、ith sensors 14, of a typical non-immersed test as is shown in the photo (b)FIG. 2 (b) Sensors 14, of a typical non-immersed test (continued)E2984/E2984M 143may require acoustic isolation or control, in order not to maskvalid acoustic emissions.7.1.7 Attach the sensors; both the couplant and sensingd
46、evice must be compatible with the surface conditions and thecomposition of the structural material being examined (seeGuide E650).7.1.8 Verify the AE monitoring system in accordance withSection 9 and Guide E2374.7.1.9 A training set of multiple known “good“ and “defec-tive“ pieces as previously dete
47、rmined by Magnetic ParticleInspection (MT) or Fluorescent Penetrant Inspection (PT) areexamined by this method. These data establish a baseline forfuture comparisons to define acceptable/reject parts, as thismethod is applicable to the repetitive examination of large setsof parts on a periodic basis
48、, and not for one time testing ofunique structures.7.1.10 AE methods can be applied to detect potential criticaldefects in high pressure piping, however 3D has an intrinsicadvantage in that cracks can be separated from other AEsources using location detection algorithms.8. Safety Precautions8.1 Hydr
49、ostatic pressurization should occur in defined stepsand holds, to minimize the chance of a sudden rupture. AEresponses above a threshold established from known goodparts, at relatively low pressure set points will signal theoperator to terminate the examination. Further, when the vesselunder test is submerged in a fluid-filled tank, the tank fluid willfurther mitigate the likelihood of personnel injury due to arupture. During pressurization stages, test personnel shouldmaintain a safe distance from the vessel under pressurization.9. Calibration and Veri
