ASTM E1734-2004 Standard Practice for Radioscopic Examination of Castings《铸件的放射性检验用标准实施规程》.pdf

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1、Designation: E 1734 04Standard Practice forRadioscopic Examination of Castings1This standard is issued under the fixed designation E 1734; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in paren

2、theses 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 a uniform procedure for radio-scopic examination of castings.1.2 This practice applies only to radioscopic examination inwhich a

3、n image is finally presented on a display screen(monitor) for evaluation. Test part acceptance may be based ona static or dynamic image. The examination results may berecorded for later review. This practice does not apply to fullyautomated systems in which evaluation is performed automati-cally by

4、a computer.1.3 Due to the many complex geometries and part configu-rations inherent with castings, it is necessary to recognize thepotential limitations associated with obtaining complete radio-scopic coverage. Consideration shall be given to areas wheregeometry or part configuration does not allow

5、for completeradioscopic coverage.1.4 The values stated in inch-pound units are to be regardedas the standard. The values given in brackets are for informa-tion only.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of th

6、e 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 ASTM Standards:2E 94 Guide for Radiographic ExaminationE 543 Practice for Agencies Performing NondestructiveTestingE 747 Pr

7、actice for Design, Manufacture and MaterialGrouping Classification of Wire Image Quality Indicators(IQI) Used for RadiologyE 1000 Guide for RadioscopyE 1025 Practice for Design, Manufacture, and MaterialGrouping Classification of Hole-Type Image Quality Indi-cators (IQI) Used for RadiologyE 1255 Pra

8、ctice for RadioscopyE 1316 Terminology for Nondestructive ExaminationsE 1411 Practice for Qualification of Radioscopic SystemsE 1453 Guide for Storage of Media That Contains Analogor Digital Radioscopic DataE 1475 Guide for Data Fields for Computerized Transfer ofDigital Radiological Test Data2.2 AS

9、NT Standards:3ASNT SNT-TC-1A Personnel Qualification and Certifica-tion in Nondestructive TestingANSI/ASNT CP-189 Personnel Qualification and Certifica-tion in Nondestructive Testing2.3 Military Standard:NAS-410 NAS Certification and Qualification of Nonde-structive Personnel (Quality Assurance Comm

10、ittee)43. Terminology3.1 DefinitionsDefinitions of terms applicable to thispractice may be found in Terminology E 1316.4. Significance and Use4.1 The requirements in this practice are intended to controlthe quality of the radioscopic images to produce satisfactoryand consistent results. This practic

11、e is not intended for con-trolling the acceptability of the casting. The radioscopicmethod may be used for detecting volumetric discontinuitiesand density variations that are within the sensitivity range ofthis practice. The dynamic aspects of radioscopy are useful formaximizing defect response.5. B

12、asis of Application5.1 The following items shall be agreed upon between thepurchaser and the supplier:5.1.1 Nondestructive Testing Agency EvaluationIf speci-fied in the contractual agreement, nondestructive testing (NDT)agencies shall be qualified and evaluated as described inPractice E 543. The app

13、licable edition of Practice E 543 shallbe specified in the contractual agreement.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.01 onRadiology (X and Gamma) Method.Current edition approved February 1, 200

14、4. Published March 2004. Originallyapproved in 1995. Last previous edition approved in 1998 as E 1734 - 98.2For 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 stand

15、ards Document Summary page onthe ASTM website.3Available from The American Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518.4Available from Aerospace Industries Association of America, Inc. 1250 EyeStreet N.W., Washington, DC 20005.1Copyright ASTM

16、 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.2 Personnel QualificationIf specified in the contrac-tual agreement, personnel performing examinations to thisstandard shall be qualified in accordance with a nationally orinternationally recogniz

17、ed NDT personnel qualification prac-tice or standard such as ANSI/ANST-CP-189, SNT-TC-1A,NAS-410 or similar document and certified by the employer orcertifying agency, as applicable. The practice or standard usedand its applicable revision shall be identified in the contractualagreement between the

18、using parties.5.1.3 Recording MediaIf required, the recording media tobe used shall be specified in accordance with the requirementsof Section 6.5.1.4 Performance MeasurementsPerformance measure-ment shall be specified in accordance with the requirements ofSection 6.5.1.5 ProcedureProcedural require

19、ments shall be speci-fied in the contractual agreement.5.1.6 RecordsRecords shall be specified in the contractualagreement.6. Apparatus6.1 Success of the radioscopic process depends on theoverall system configuration and the selection of appropriatesubsystem components. Guidance on the selection of

20、sub-system components and the overall system configuration isprovided in Guide E 1000 and Practice E 1255. Guidance onthe initial qualification and periodic re-qualification of theradioscopic system is provided in Practice E 1411. The suit-ability of the radioscopic system shall be demonstrated byat

21、tainment of the required image quality and compliance withall other requirements stipulated herein.6.2 Equipment:6.2.1 Radiation Source (X-Ray or Gamma-Ray)Selectionof the appropriate source is dependent on variables regardingthe casting being examined, such as material composition andthickness. Gui

22、dance on selection of the radiation source maybe found in Practice E 1255.6.2.2 Manipulation SubsystemSelection of the appropri-ate manipulation system (where applicable) is dependent onvariables such as the size and orientation of the object beingexamined and the range of motions, speed of travel,

23、andsmoothness of motion. Guidance on selection of the manipu-lation subsystem may be found in Practice E 1255.6.2.3 Detector SubsystemSelection of the appropriate de-tection system is dependent on variables such as the materialand size of the object being examined and the energy andintensity of the

24、radiation used for the examination. Guidanceon selection of the detector subsystem may be found in PracticeE 1255.6.2.4 Image Processing SubsystemWhere agreed uponbetween the purchaser and the supplier, image processingsystems may be used for noise reduction through imageintegration or averaging, co

25、ntrast enhancement, and otherimage processing operations. Users of digital image processingare cautioned to test image processing parameters thoroughlybefore use. For example, some spatial filter functions producedirectional results and may suppress desired image informa-tion. Other spatial filters

26、can introduce artifacts into the image.6.2.5 Image Display SubsystemSelection of the appropri-ate image display is critical to the transfer of image informationfrom the radioscopic system to the person making the accept-reject decision. The image display should be suitably sized andplaced in a contr

27、olled environment with subdued lighting tomaximize the transfer of image information to the radioscopicsystem operator.6.2.6 CollimationSelection of appropriate collimation isdependent on the geometry of the object being examined. It isgenerally useful to select collimation to limit the primaryradia

28、tion beam to the detector area or region of interest,whichever is smaller, thereby limiting scatter radiation in orderto improve radioscopic image quality.6.2.7 Filters and MaskingFilters and masking may beused to improve image quality by alleviating contrast reduc-tions caused by low-energy scatter

29、ed radiation. Guidance onthe use of filters and masking is provided in Guide E 94.6.3 Performance MeasurementRadioscopic examinationsystem performance parameters must be determined initiallyand monitored regularly to ensure consistent results. The bestmeasure of total radioscopic examination system

30、performancecan be made with the system in operation, using a test objectsimilar to the test part under actual operating conditions. Thisindicates the use of an actual or simulated test object orcalibration block containing actual or simulated features thatmust be detected reliably. Such a calibratio

31、n block will providea reliable indication of the radioscopic examination systemscapabilities. Conventional wire or plaque-type image qualityindicators (IQIs) may be used in place of, or in addition to, thesimulated test object or calibration block. Performance mea-surement methods are subject to agr

32、eement between thepurchaser and the supplier of radioscopic examination services.6.3.1 Performance Measurement IntervalsSystem perfor-mance measurement techniques should be standardized so thatperformance measurement tests may be duplicated readily atspecified intervals. Radioscopic examination perf

33、ormanceshould be evaluated at sufficiently frequent intervals, as may beagreed upon between the purchaser and the supplier of radio-scopic examination services, in order to minimize the possi-bility of time-dependent performance variations.6.3.2 Measurement with IQIsSystem performance mea-surements

34、using IQIs shall be in accordance with acceptedindustry standards describing the use of IQIs. The IQIs shouldbe placed on the radiation source side of the test object, asclose as possible to the region of interest. The use of wire IQIsshould also take into account the fact that the radioscopicexamin

35、ation may exhibit asymmetrical sensitivity, in whichcase the wire diameter axis shall be oriented along the systemsaxis of least sensitivity. Selection of IQI thickness should beconsistent with the test part radiation path length.6.3.3 Measurement With a Calibration BlockThe calibra-tion block may b

36、e an actual test part with known features thatare representative of the range of features to be detected, or itmay be fabricated to simulate the test object with a suitablerange of representative features. Alternatively, the calibrationblock may be a one-of-a-kind or few-of-a-kind reference testobje

37、ct containing known imperfections that have been verifiedindependently. Calibration blocks containing known, naturalE1734042defects are useful on a single-task basis, but they are notuniversally applicable. A duplicate manufactured calibrationblock should be used where standardization among two ormo

38、re radioscopic examination systems is required. The cali-bration blocks should approximate the test object as closely asis practical, being made of the same material with similardimensions and features in the radioscopic examination regionof interest. Manufactured calibration blocks shall includefea

39、tures at least as small as those that must be detected reliablyin the actual test object in locations where they are expected tooccur. It is permissible to produce the calibration block insections where features are internal to the test object. Calibra-tion block details are a matter of agreement be

40、tween thepurchaser and the supplier of radioscopic examination services.6.3.3.1 Use of a Calibration BlockThe calibration blockshall be placed in the radioscopic examination system in thesame position as the actual test object. The calibration blockmay be manipulated through the same range of motion

41、s as areavailable for the actual test object so as to maximize theradioscopic examination systems response to the simulatedimperfections.6.3.3.2 Radioscopic Examination TechniquesTechniquesused for the calibration block shall be identical to those usedfor actual examination of the test part. Techniq

42、ue parametersshall be listed and include, as a minimum, radiation beamenergy, intensity, focal spot size, enlargement, digital imageprocessing parameters, manipulation scan plan, and scanningspeed.6.3.4 Use of Calibrated Line Pair Test Pattern and StepWedgeA calibrated line pair test pattern and ste

43、p wedge maybe used, if desired, to determine and track the radioscopicsystem performance in terms of spatial resolution and contrastsensitivity. The line pair test pattern is used without anadditional absorber to evaluate system spatial resolution. Thestep wedge is used to evaluate system contrast s

44、ensitivity.6.3.4.1 The step wedge must be made of the same materialas the test part, with steps representing 100, 99, 98, 97, and96 % of both the thickest and thinnest material sections to beexamined. The thinner steps shall be adjacent to the 100 %thickness in order to facilitate discerning the min

45、imum visiblethickness step. Other thickness steps are permissible uponagreement between the purchaser and the supplier of radio-scopic examination services.6.3.4.2 The line pair test pattern and step wedge tests shallbe conducted in a manner similar to the performance measure-ments for the IQI or ca

46、libration block. It is permissible toadjust the X-ray energy and intensity to obtain a usable linepair test pattern image brightness. In the case of a radioisotopeor X-ray generating system in which the energy or intensitycannot be adjusted, additional filtration may be added to reducethe brightness

47、 to a useful level. Contrast sensitivity shall beevaluated at the same energy and intensity levels as are usedfor the radioscopic technique.6.3.4.3 A system that exhibits a thin section contrast sensi-tivity of 3 %, a thick section contrast sensitivity of 2 %, and aspatial resolution of 3 line pairs

48、/mm may be said to have aquality level of 3%2%3lp/mm.6.3.4.4 The line pair test pattern and step wedge may beused to make more frequent periodic system performancechecks than are required in 6.3.1. Resolution and contrastsensitivity checks must be correlated with IQI or calibrationblock performance

49、measurements. This may be accomplishedby first evaluating the system performance in accordance with6.3.2 or 6.3.3 and immediately thereafter determining theequivalent spatial resolution and contrast sensitivity values.6.4 Location and Identification MarkersLead numbersand letters may be used to designate the part number andlocation number, as needed, provided they do not mask regionsof interest on the casting. On-part identification is not requiredwhere the manipulator is programmable or manipulator coor-dinates are provided as a means of ensuring that all reg