1、Designation: E2422 17Standard Digital Reference Images forInspection of Aluminum Castings1This standard is issued under the fixed designation E2422; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These digital reference images illustrate the types anddegrees of discontinuities that may be found in aluminum-alloycastings. The castings
3、 illustrated are in thicknesses of14 in.(6.35 mm) and34 in. (19.1 mm).1.2 All areas of this standard may be open to agreementbetween the cognizant engineering organization and thesupplier, or specific direction from the cognizant engineeringorganization. These items should be addressed in the purcha
4、seorder or the contract.1.3 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 These digital reference images are not intended toillustr
5、ate the types and degrees of discontinuities found inaluminum-alloy castings when performing film radiography. Ifperforming film radiography of aluminum-alloy castings, referto Reference Radiographs E155.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with
6、 its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 Only licensed copies of the software and images shall beutilized for production inspection.
7、 A copy of the ASTM/Userlicense agreement shall be kept on file for audit purposes.NOTE 1The set of digital reference images consists of 13 digital files,software to load the desired format and specific instructions on the loadingprocess. The 13 reference images illustrate eight grades of severity a
8、ndcontain an image of a step wedge and two line pair gauges.Available fromASTM International Headquarters, Order No: RRE02422. Refer toPractice E2002 for line pair gauge details.NOTE 2Reference radiographs applicable to aluminum and magne-sium die castings up to 1 in. (25 mm) in thickness are contai
9、ned inReference Radiographs E505.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade
10、Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E155 Reference Radiographs for Inspection of Aluminumand Magnesium CastingsE505 Reference Radiographs for Inspection of Aluminumand Magnesium Die CastingsE1316 Terminology for Nondestructive Examinatio
11、nsE2002 Practice for Determining Total Image Unsharpnessand Basic Spatial Resolution in Radiography and Radios-copy2.2 SMPTE Practice:3RP133 SMPTE Recommended Practice Specifications forMedical Diagnostic Imaging Test Pattern for TelevisionMonitors and Hard-Copy Recording Cameras2.3 ASTM Adjuncts:Di
12、gital Reference Images for Inspection of AluminumCastings43. Terminology3.1 DefinitionsDefinitions of terms used in this standardmay be found in Terminology E1316.3.2 Definitions of Terms Specific to This Standard:3.2.1 The terms relating to discontinuities used in thesedigital reference images are
13、described based upon radiographicappearance.3.2.2 aliasingartifacts 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 moir patterns.1This standard is under the jurisdi
14、ction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.02 onReference Radiological Images.Current edition approved Nov. 1, 2017. Published November 2017. Originallyapproved in 2005. Last previous edition approved in 2011 as E2422 - 11. DOI:10.1520
15、/E2422-17.2For 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.3Available from Society of Motion Picture and Telev
16、ision Engineers, 3 BarkerAvenue White Plains, NY 10601; or http:/www.smpte.org/smpte_store/4Available from ASTM International Headquarters. Order Reference Radio-graph No. RRE2422.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO
17、 Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued b
18、y the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.3 contrast normalizationthe adjustment of contrastbetween the production image and the reference image thatmakes the change in digital driving level versus change inthickness equal for both images.3.2.4 DDLdigital drivin
19、g level also known as monitorpixel value.3.2.5 foreign materialsappear as isolated, irregular, orelongated variations in brightness, not corresponding to varia-tions in thickness of material, nor to cavities. They may be dueto the presence of sand, slag, oxide or dross, or metal ofdifferent density.
20、3.2.6 gas holesappear as round or elongated, smooth-edged dark spots in a negative image, occurring individually, inclusters, or distributed throughout the casting.3.2.7 gas porosityrepresented by round or elongated darkspots in a negative image corresponding to minute voidsusually distributed throu
21、gh the entire casting.3.2.8 measured resolutionthe characteristic resolution of adigital radiographic system as measured in accordance with8.5.3.2.9 shrinkage cavityappears as a dendritic, filamentary,or jagged darkened area in a negative image.3.2.10 shrinkage porosity or sponge (nonferrous alloys)
22、alocalized lacy or honeycombed darkened area in a negativeimage.3.2.11 system resolutionthe detector-measured resolutiondivided by the geometric magnification.4. Significance and Use54.1 These digital reference images are intended for refer-ence only, but are so designed that acceptance standards, w
23、hichmay be developed for particular requirements, can be specifiedin terms of these digital reference images. The illustrations aredigital images of castings that were produced under conditionsdesigned to develop the discontinuities. The images of the14-in. (6.35-mm) castings are intended to be used
24、 in thethickness range up to and including12-in. (12.7 mm). Theimages of the34-in. (19.1-mm) castings are intended to be usedin the thickness range of over12 in., up to and including 2 in.(51 mm).4.2 Image DeteriorationMany conditions can affect theappearance and functionality of digital reference i
25、mages. Forexample, electrical interference, hardware incompatibilities,and corrupted files or drivers may affect their appearance. TheASTM E2002 line pair gauges located in the lower right handcorner of each digital reference can be used as an aid to detectimage deterioration by comparing the measur
26、ed resolutionusing the gauges to the resolution stated on the digital referenceimage. Do not use the digital reference images if theirappearance has been adversely affected such that the interpre-tation and use of the images could be influenced.4.3 Agreement should be reached between cognizant engi-
27、neering organization and the supplier that the system used bythe supplier is capable of detecting and classifying the requireddiscontinuities.5. Basis for Application5.1 The digital reference images may be applied as accep-tance standards tailored to the end use of the product. Appli-cation of these
28、 digital reference images as acceptance standardsshould be based on the intended use of the product and thefollowing considerations (see Note 3).5.1.1 An area of like size to that of the digital referenceimage shall be the unit areas by which the production digitalimage is evaluated, and any such ar
29、ea shall meet the require-ments as defined for acceptability.5.1.2 Any combination or subset of these digital referenceimages may be used as is relevant to the particular application.Different grades or acceptance limits may be specified for eachdiscontinuity type. Furthermore, different grades may
30、be speci-fied for different regions or zones of a component.5.1.3 Special considerations may be required where morethan one discontinuity type is present in the same area. Anymodifications to the acceptance criteria required on the basis ofmultiple discontinuity types must be specified.5.1.4 Product
31、ion digital images containing porosity, gas orinclusions may be rated by the overall condition with regard tosize, number, and distribution. These factors should be consid-ered in balance.5.1.5 As a minimum, the acceptance criteria should containinformation addressing: zoning of the part (if applica
32、ble), theacceptance severity level for each discontinuity type, and thespecified area to which the digital reference images are to beapplied.NOTE 3Caution should be exercised in specifying the acceptancecriteria to be met in a casting. Casting design coupled with foundrypractice should be considered
33、. It is advisable to consult with themanufacturer/foundry before establishing the acceptance criteria to ensurethe desired quality level can be achieved.6. Procedure for Evaluation6.1 Select the appropriate Digital Reference Image.6.2 Apply contrast adjustments to the reference image byeither method
34、 described in 9.5.6.3 Evaluation shall be performed against the adjustedreference image.7. Description7.1 The digital reference images listed in Table 1 illustrateeach type of discontinuity in eight grades. Although eightgrades of each discontinuity are shown, a numerically smallergraded set of disc
35、ontinuities based on these digital referenceimages could be used for acceptance standards.7.2 The alloys used to reproduce the various discontinuitiesare as listed in Table 2.7.3 The step wedges shown in the digital reference imagesare made of 6061 Aluminum with the thickness of the stepslisted in T
36、able 3.5A study was performed that compared film to digital modalities for theclassification of aluminum casting discontinuities. Results of this study are availablefrom ASTM as RR:E07-1004.E2422 172NOTE 4Misruns, core shift, cold shut, and surface irregularities arenot illustrated, as they are read
37、ily identifiable by surface inspection or byother means of nondestructive testing.8. Digital Image Installation Procedure8.1 Follow the instructions provided with the digital refer-ence images to load the reference image software.8.2 The software files will be saved to a default locationduring insta
38、llation unless instructed otherwise during the loadprocess.8.3 The software will require the user to specify either apositive or negative image. Select the option to match theviewing format (positive or negative image) of the systemsviewing software.8.4 The software load process will require the dig
39、italreference image resolution to be specified to the nearest10-micron increment. Select the resolution that will mostclosely match the system resolution. System resolution is thedetector resolution divided by the geometric magnification tobe used during inspection.8.5 Determine the system spatial r
40、esolution (also referred toas SRbimageor SRmin) at the magnification to be used forproduction imaging using the duplex wire gauge as describedin Practice E2002.8.6 Compare the measured system spatial resolution to thetheoretical resolution determined as the nominal pixel sizedivided by the geometric
41、 magnification. Where parts are placeddirectly on the detector, use the nominal pixel size as thetheoretical resolution. If the measured spatial resolution differsby no more than 30 % from the theoretical resolution, use thetheoretical resolution as the detector resolution.8.7 If the measured resolu
42、tion differs from the theoreticalresolution by more than 30 % adjust the process parametersand measure the resolution again. For computed radiography, asuggested parameter to change is the sampling resolution.NOTE 5The resolution conversion process is performed by theprovided load software. This pro
43、cess is performed by grouping pixels intobins and calculating the average value of the pixels in the bin. Thisaverage value is then the pixel value for the pixels of the same size andlocation as the subject bins.9. Viewer Software Requirements9.1 Viewer software shall be capable of importing thedigi
44、tal reference images as either a 16-bit grayscale uncom-pressed TIFF format or in the DICONDE format.9.2 Viewer software shall be capable of importing andstoring digital reference images at resolutions in 10 micronincrements starting from 10 microns, and displaying theseimages without loss of data i
45、ntegrity or resolution.9.3 Digital reference images shall be selectable by discon-tinuity type.9.4 It shall be possible to view production and digitalreference images simultaneously on a single monitor oroptionally, on several monitors that are matched to provideequal brightness for a given digital
46、driving level.9.5 The contrast of the reference image shall be adjusted toassure the displayed image reflects a suitable gray value changecommensurate with material thickness change. Contrast adjust-ment shall be performed in accordance with 9.5.1 or 9.5.2 asdirected by the cognizant engineering org
47、anization.9.5.1 Manual Contrast MethodThe contrast of the refer-ence image shall be adjusted to provide an appropriate presen-tation of discontinuities. This may be accomplished, forexample, by comparison with the image in the equivalent filmreference radiograph. The stepwedge image may be used togu
48、ide the establishment of the display contrast for the referenceimages. This may be accomplished by performing a histogramequalization on defined steps of the stepwedge or by setting thedisplay window width to a fixed value. The specific method tobe used for establishing the display of the reference
49、image,including the acceptable range of the window width, shall bedocumented and approved by the Level 3. Once establishedand approved by the Level 3, the window width of thereference image shall not be modified by the user.9.5.2 Contrast Normalization MethodThe user shall em-ploy software tools approved by the cognizant engineeringorganization to establish a relationship between the referenceTABLE 1 Digital Reference Images for Aluminum CastingsDiscontinuity CastingThickness in.AApplicable CastingThickness in.AGas holes14 up to12, inclGas holes34 over12
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