1、Designation: E2868 13Standard Digital Reference Images forSteel Castings up to 2 in. (50.8 mm) in Thickness1This standard is issued under the fixed designation E2868; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 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 These digital reference images illustrate variouscategories, types, and severity levels of discontinuities occur-ring in s
3、teel castings that have section thicknesses up to 2 in.(50.8 mm). The digital reference images are an adjunct to thisstandard and must be purchased separately from ASTMInternational, if needed (see 2.3). Categories and severitylevels for each discontinuity type represented by these digitalreference
4、images are described in 1.2.NOTE 1The basis of application for these reference images requires aprior purchaser supplier agreement of radiographic examination attributesand acceptance criteria as described in Sections 4, 6, and 7 of thisstandard.1.2 These digital reference images consist of three se
5、paratevolumes (see Note 2) as follows: (I) medium voltage (nominal250-kV) X rays, (II) 1-MV X rays and Iridium-192 radiation,and (III) 2-MV to 4-MV X rays and Cobalt-60 radiation.Unless otherwise specified in a purchaser supplier agreement(see 1.1), each volume is for comparison only with production
6、digital images produced with radiation energy levels within thethickness range covered by this standard. Each volume consistsof six categories of graded discontinuities of increasing sever-ity level and four categories of ungraded discontinuities.Reference images containing ungraded discontinuities
7、areprovided as a guide for recognition of a specific castingdiscontinuity type where severity levels are not needed. Thefollowing is a list of discontinuity categories, types, andseverity levels for the adjunct digital reference images of thisstandard:1.2.1 Category A Gas porosity; severity levels 1
8、 through5.1.2.2 Category B Sand and slag inclusions; severity levels1 through 5.1.2.3 Category C Shrinkage; 4 types:1.2.3.1 Calinear shrinkage Severity levels 1 through 5.1.2.3.2 Cbfeathery shrinkage Severity levels 1 through 5.1.2.3.3 Ccsponge shrinkage Severity levels 1 through 5.1.2.3.4 Cdcombina
9、tions of linear, feathery, and spongeshrinkage Severity levels 1 through 5.1.2.4 Category DCrack; 1 illustration.1.2.5 Category EHot Tear; 1 illustration.1.2.6 Category FInsert; 1 illustration.1.2.7 Category GMottling; 1 illustration. (See Note 3.)NOTE 2The digital reference images consist of the fo
10、llowing:Volume I: Medium Voltage (nominal 250-kVp) X-Ray Reference Images Set of 34 illustrations.Volume II: 1-MV X Rays and Iridium-192 Reference Images Set of 34illustrations.Volume III: 2-MV to 4-MV X Rays and Cobalt-60 Reference Images Setof 34 illustrations.NOTE 3Although Category G Mottling is
11、 listed for all threevolumes, the appearance of mottling is dependent on the level of radiationenergy. Mottling appears reasonably prominent in Volume I; however,because of the higher radiation energy levels mottling may not be apparentin Volume II nor Volume III.1.3 All areas of this standard may b
12、e open to agreementbetween the cognizant engineering organization and thesupplier, or specific direction from the cognizant engineeringorganization. These items should be addressed in the purchaseorder or the contract.1.4 These digital reference images are not intended toillustrate the types and deg
13、rees of discontinuities found in steelcastings up to 2 in. (50.8 mm) in thickness when performingfilm radiography. If performing film radiography of steelcastings up to 2 in. (50.8 mm) in thickness, refer to ReferenceRadiographs E446.1.5 Only licensed copies of the software and images shall beutiliz
14、ed for production inspection. A copy of the ASTM/Userlicense agreement shall be kept on file for audit purposes. (SeeNote 4.)NOTE 4Each volume of digital reference images consists of 7 digitaldata files, software to load the desired format and specific instructions onthe loading process. The 34 refe
15、rence images in each volume illustrate sixcategories of graded discontinuities and four categories of ungradeddiscontinuities and contain an image of a step wedge. Available fromASTM International Headquarters, Order No: RRE2868.1.6 The values stated in inch-pound units are to be regardedas standard
16、. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the1This standard is under the jurisdiction
17、of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.02 onReference Radiological Images.Current edition approved Dec. 1, 2013. Published December 2013. Originallyapproved in 2013. DOI: 10.1520/E2868-13Copyright ASTM International, 100 Barr Harbor Driv
18、e, PO Box C700, West Conshohocken, PA 19428-2959. United States1responsibility 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 ASTM Standards:2E446 Reference Radiogra
19、phs for Steel Castings Up to 2 in.(50.8 mm) in ThicknessE1316 Terminology for Nondestructive ExaminationsE2446 Practice for Classification of Computed RadiologySystemsE2597 Practice for Manufacturing Characterization of Digi-tal Detector Arrays2.2 SMPTE Practice:3RP133 SMPTE Recommended Practice Spe
20、cifications forMedical Diagnostic Imaging Test Pattern for TelevisionMonitors and Hard-Copy Recording Cameras2.3 ASTM Adjunct2RRE2868 Digital Reference Images for Inspection of SteelCastings Up to 2 in. (50.8 mm) in Thickness3. Terminology3.1 Definitions:3.1.1 Definitions of terms used in this stand
21、ard may befound in Terminology E1316.3.2 Definitions of Terms Specific to This Standard:3.2.1 aliasing, nartifacts that appear in an image when thespatial frequency of the input is higher than the output iscapable of reproducing. This will often appear as jagged orstepped sections in a line or as mo
22、ir patterns.3.2.2 classification specification, na set of user definedacceptance criterion that prescribes the radiographic workman-ship discontinuity class requirements for a specified usercasting service application (see Sections 6 and 7).3.2.3 contrast normalization, nthe adjustment of contrastbe
23、tween the production image and the reference image thatmakes the change in digital driving level versus change inthickness equal for both images.3.2.4 DDL, ndigital driving level also known as monitorpixel value.3.2.5 discontinuity category, na nomenclature systemused for grouping discontinuity type
24、s. For example: linearshrinkage is assigned category “Ca” where “C” represents thegeneral shrinkage category and “a” represents the specificlinear shrinkage discontinuity type.3.2.6 discontinuity class, nan assigned workmanship fab-rication quality rating characterized by a discontinuity type,catego
25、ry and severity level. For example: “Ca 2” is a discon-tinuity class comprised of linear shrinkage with a severity levelof “2.”3.2.7 discontinuity severity level, na relative rank in termsof “quantity, size, and distribution” of a collection of discon-tinuities where “1” is the least and “5” is the
26、greatest “quantity,size, and distribution” present on the reference image. Ex-ample: a severity level of “1” is more restrictive (requires ahigher level of workmanship fabrication quality) than a sever-ity level of “2”.3.2.8 discontinuity type, na specific discontinuity charac-terized by its cause a
27、nd appearance. For example: linearshrinkage is a specific discontinuity type.3.2.9 graded illustrations, na category of discontinuitythat is assigned a severity level.3.2.10 measured resolution, nthe characteristic resolutionof a digital radiographic system as measured in accordancewith 10.5.3.2.11
28、production image, nan image under review forcompliance with this standard.3.2.12 prorating, vassignment of quantity, size, and dis-tribution on a production image in proportion to a similar sizearea of a reference image. For example: a production imagecovers an area that is smaller than the unit are
29、a of a referenceimage and the extent of discontinuity on the applicablereference image is reduced proportionately.3.2.13 ungraded illustrations, na category of discontinu-ity without an assigned severity level.4. Significance and Use4.1 Graded reference images are intended to provide a guideenabling
30、 recognition of specific casting discontinuity types andrelative severity levels that may be encountered during typicalfabrication processes. Reference images containing ungradeddiscontinuities are provided as a guide for recognition of aspecific casting discontinuity type where severity levels are
31、notneeded. These reference images are intended as a basis fromwhich manufacturers and purchasers may, by mutualagreement, select particular discontinuity classes to serve asstandards representing minimum levels of acceptability (seeSections 6 and 7).4.2 Reference images represented by this standard
32、may beused, as agreed upon in a purchaser supplier agreement, forenergy levels, thicknesses, or both outside the range of thisstandard when determined applicable for the casting serviceapplication.4.3 Procedures for evaluation of production images usingapplicable reference images of this standard ar
33、e prescribed inSection 8; however, there may be manufacturing-purchaserissues involving specific casting service applications where itmay be appropriate to modify or alter such requirements.Where such modifications may be appropriate for the castingapplication, all such changes shall be specifically
34、 called-out inthe purchaser supplier agreement or contractual document.Section 9 addresses purchaser supplier requisites for whereweld repairs may be required.4.4 Agreement should be reached between cognizant engi-neering organization and the supplier that the system used bythe supplier is capable o
35、f detecting and classifying the requireddiscontinuities.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.3Avai
36、lable from the Society of Motion Picture and Television Engineers, 3Barker Avenue White Plains, NY 10601; or http:/www.smpte.org/smpte_store/E2868 1325. Determination of Radiographic Acceptance Criteria5.1 For purposes of evaluation of castings, a determinationmust be made of the radiographic discon
37、tinuity acceptancecriteria to be assigned to individual castings or specific areas ofcastings. The determination of the applicable radiographicdiscontinuity criteria shall be based on an evaluation of thecasting applications, design, and service requirements. In theseevaluations, consideration shall
38、 be given to such factors aspressure, temperature, section thickness, applicable designsafety factor (preferably based on stress analysis), vibration,shock, resistance to corrosion, involvement of penetratingradiations or radiation products, and involvement of dangerousgases or liquids.5.2 For each
39、individual casting or specific area of a castingto be radiographed, the discontinuity criteria must be clearlyspecified. For example, severity level 2 might be specified forlinear shrinkage, Category Ca, and severity level 3 for gasporosity, Category A, since the latter are generally much lessdelete
40、rious to tensile properties (see Section 6).6. Acceptance Criteria Specifications6.1 The applicable radiographic discontinuity acceptancecriteria should be designated by the contracting agency informal specifications or on drawings and in specific contractsor orders. The specifications, drawings, co
41、ntracts, or ordershould also designate the sampling plan for the castings to beradiographed and the extent of radiographic coverage, radio-graphic practice to be followed, image quality desired as wellas the severity of the acceptable discontinuity for the gradedcategories.7. Evaluation Procedure7.1
42、 Select the appropriate digital reference image to matchthe condition to be evaluated in the production image.7.2 Apply contrast adjustments to the reference image usingthe method described in Section 10.5.7.3 Evaluation shall be performed against the adjustedreference image.7.4 Compare the producti
43、on images of the casting submittedfor evaluation with the reference images representing the samegeneral energy range within the thickness range of this stan-dard (unless otherwise specifiedsee Section 4).7.5 When the severity level of discontinuities in the produc-tion image being evaluated is equal
44、 to or less than the severitylevel in the specified reference image, that part of the castingrepresented by the production image shall be acceptable. If theproduction image shows discontinuities of greater severity thanthe reference image, that part of the casting shall be rejected.7.6 A unit area o
45、n the production image shall be evaluatedto a unit area of like size on the reference image. Any unitevaluation area that shares a discontinuity with an adjacent unitevaluation area shall meet the minimum unit area acceptabilityrequirements within the combined unit area. When the unitarea of interes
46、t of a production image is less than the unit areaof the applicable reference image, such unit area of theproduction image shall be prorated to the reference image area.7.7 When two or more categories of discontinuity arepresent in the same production image, the predominatingdiscontinuities, if unac
47、ceptable, shall govern without regard tothe other categories of discontinuity and the casting rejected.7.8 When two or more categories of discontinuity arepresent to an extent equal to the maximum permissible level asshown in the applicable standards for each category, then thatpart of the casting s
48、hall be judged unacceptable. When two ormore categories of discontinuity are present in the same imageto an extent less than the maximum permissible level, as shownin the applicable standards for each category, the severity levelshall be evaluated by the overall aggregate condition. Theaggregate con
49、dition is defined as the balance of quantity, size,and distribution of the collection of discontinuities and shallnot exceed the aggregate condition of the applicable referenceimage.7.9 Reference images are provided showing a variety ofshrinkage discontinuity types. Production images showingshrinkage shall be judged by the most representative referenceimage.7.10 This standard does not specify limiting criteria for asingle size of discontinuity, maximum number of discontinui-ties per unit area evaluated, specific dimensional spacing, oralig
