1、Designation: E2422 11Standard 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 These digital reference images illustrate the types anddeg
3、rees of discontinuities that may be found in aluminum-alloycastings. The castings illustrated are in thicknesses of14 in.(6.35 mm) and34 in. (19.1mm).1.2 All areas of this standard may be open to agreementbetween the cognizant engineering organization and the sup-plier, or specific direction from th
4、e cognizant engineeringorganization. These items should be addressed in the purchaseorder 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
5、 considered standard.1.4 These digital reference images are not intended toillustrate 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 stand
6、ard 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 use.1.6 Only licensed copies of t
7、he software and images shall beutilized for production inspection. 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 loadingproc
8、ess. The 13 reference images illustrate eight grades of severity andcontain 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 m
9、agne-sium die castings up to 1 in. (25 mm) in thickness are contained inReference Radiographs E505.2. Referenced Documents2.1 ASTM Standards:2E155 Reference Radiographs for Inspection of Aluminumand Magnesium CastingsE505 Reference Radiographs for Inspection of Aluminumand Magnesium Die CastingsE131
10、6 Terminology for Nondestructive ExaminationsE2002 Practice for Determining Total Image Unsharpnessin RadiologyE2446 Practice for Classification of Computed RadiologySystemsE2597 Practice for Manufacturing Characterization of Digi-tal Detector Arrays2.2 SMPTE Practice:3RP133 SMPTE Recommended Practi
11、ce Specifications forMedical Diagnostic Imaging Test Pattern for TelevisionMonitors and Hard-Copy Recording Cameras2.3 ASTM Adjuncts:Digital Reference Images for Inspection of Aluminum Cast-ings43. Terminology3.1 DefinitionsDefinitions of terms used in this standardmay be found in Terminology E1316.
12、3.2 Definitions of Terms Specific to This Standard:3.2.1 The terms relating to discontinuities used in thesedigital reference images are described based upon radiographicappearance.3.2.2 aliasingartifacts that appear in an image when thespatial frequency of the input is higher than the output is1Thi
13、s standard is under the jurisdiction 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, 2011. Published December 2011. Originallyapproved in 2005. Last previous edition approved in
14、2005 as E2422 - 05. DOI:10.1520/E2422-11.2For 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.3Available from Soci
15、ety of Motion Picture and Television Engineers, 3 BarkerAvenue White Plains, NY 10601; or http:/www.smpte.org/smpte_store/4Available from ASTM International Headquarters. Order Reference Radio-graph No. RRE2422.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM Interna
16、tional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.capable of reproducing. This will often appear as jagged orstepped sections in a line or as moir patterns.3.2.3 contrast normalizationthe adjustment of contrastbetween the production image and the reference i
17、mage thatmakes the change in digital driving level versus change inthickness equal for both images.3.2.4 DDLdigital driving 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
18、 of material, nor to cavities. They may be dueto the presence of sand, slag, oxide or dross, or metal ofdifferent density.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 poro
19、sityrepresented by round or elongated darkspots in a negative image corresponding to minute voidsusually distributed through the entire casting.3.2.8 measured resolutionthe characteristic resolution ofa digital radiographic system as measured in accordance with8.5.3.2.9 shrinkage cavityappears as a
20、dendritic, filamentary,or jagged darkened area in a negative image.3.2.10 shrinkage porosity or sponge (nonferrous alloys)alocalized lacy or honeycombed darkened area in a negativeimage.3.2.11 system resolutionthe detector-measured resolutiondivided by the geometric magnification.4. Significance and
21、 Use54.1 These digital reference images are intended for refer-ence only, but are so designed that acceptance standards, whichmay be developed for particular requirements, can be specifiedin terms of these digital reference images. The illustrations aredigital images of castings that were produced u
22、nder conditionsdesigned to develop the discontinuities. The images of the14-in. (6.35-mm) castings are intended to be used 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 inclu
23、ding 2 in.(51 mm).4.2 Image DeteriorationMany conditions can affect theappearance and functionality of digital reference images. Forexample, electrical interference, hardware incompatibilities,and corrupted files or drivers may affect their appearance. TheASTM E2002 line pair gauges located in the l
24、ower right handcorner of each digital reference can be used as an aid to detectimage deterioration by comparing the measured 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
25、that the interpre-tation and use of the images could be influenced.4.3 Agreement should be reached between cognizant engi-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 digi
26、tal reference images may be applied as accep-tance standards tailored to the end use of the product. Appli-cation of these 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 tha
27、t of the digital referenceimage shall be the unit areas by which the production digitalimage is evaluated, and any such area 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 applica
28、tion.Different grades or acceptance limits may be specified for eachdiscontinuity type. Furthermore, different grades may 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. Anymod
29、ifications to the acceptance criteria required on the basis ofmultiple discontinuity types must be specified.5.1.4 Production 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 i
30、n balance.5.1.5 As a minimum, the acceptance criteria should containinformation addressing: zoning of the part (if applicable), 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
31、specifying the acceptancecriteria to be met in a casting. Casting design coupled with foundrypractice should be considered. It is advisable to consult with themanufacturer/foundry before establishing the acceptance criteria to ensurethe desired quality level can be achieved.6. Procedure for Evaluati
32、on6.1 Select the appropriate Digital Reference Image.6.2 Apply contrast adjustments to the reference image byeither method 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 di
33、scontinuity in eight grades. Although eightgrades of each discontinuity are shown, a numerically smallergraded set of discontinuities 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
34、 The step wedges shown in the digital reference imagesare made of 6061 Aluminum with the thickness of the stepslisted in Table 3.NOTE 4Misruns, core shift, cold shut, and surface irregularities are5A study was performed that compared film to digital modalities for theclassification of aluminum casti
35、ng discontinuities. Results of this study are availablefrom ASTM as RR:E07-1004.E2422 112not illustrated, as they are readily identifiable by surface inspection or byother means of nondestructive testing.8. Digital Image Installation Procedure8.1 Follow the instructions provided with the digital ref
36、er-ence images to load the reference image software.8.2 The software files will be saved to a default locationduring installation 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 thevie
37、wing format (positive or negative image) of the systemsviewing software.8.4 The software load process will require the digitalreference image resolution to be specified to the nearest10-micron increment. Select the resolution that will mostclosely match the system resolution. System resolution is th
38、edetector resolution divided by the geometric magnification tobe used during inspection.8.5 Determine the detector resolution for digital detectorarrays (DDA) as described in Practice E2597 and for CRsystems in Practice E2446.8.6 Compare the measured resolution to the theoreticalresolution determine
39、d by pixel size. If the measured resolutiondiffers by no more than 30 % from the theoretical resolutionuse the theoretical resolution as the detector resolution.8.7 If the measured resolution differs from the theoreticalresolution by more than 30 % adjust the process parametersand measure the resolu
40、tion again. For computed radiography, asuggested parameter to change is the sampling resolution.NOTE 5The resolution conversion process is performed by the pro-vided load software. This process is performed by grouping pixels intobins and calculating the average value of the pixels in the bin. Thisa
41、verage 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 thedigital reference images as either a 16-bit grayscale uncom-pressed TIFF format or in the DICONDE format.9.2 Viewer
42、 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 integrity or resolution.9.3 Digital reference images shall be selectable by discon-tinuity type.9.4 It shall be
43、possible to view production and digitalreference images simultaneously on a single monitor or op-tionally, on several monitors that are matched to provide equalbrightness for a given digital driving level.9.5 The contrast of the reference image shall be adjusted toassure the displayed image reflects
44、 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 organization.9.5.1 Manual Contrast MethodThe Radiographic LevelIII shall adjust the contrast of the reference im
45、age to provide anappropriate presentation of discontinuities. This may be ac-complished by comparison with the image in the equivalentfilm reference radiograph. Once established and secured, thewindow width of the reference image shall not be modified bythe user.9.5.2 Contrast Normalization MethodTh
46、e user shall em-ploy software tools approved by the cognizant engineeringorganization to establish a relationship between the referenceand production image such that the change in gray scale versuschange in material thickness will be similar in both images.Once established the normalized contrast re
47、lationship betweenthe production and reference image shall not be modifiedfurther by the user.9.6 Viewer software shall provide the capability to lock thezoom levels of the production and reference digital images, sothat both images are simultaneously adjusted.9.7 Viewer software shall be capable of
48、 displaying the rawdata value at the current cursor position.9.8 Viewer software shall be capable of displaying the DDLat the current cursor position.9.9 Viewer software shall be capable of displaying thedistance between two selected points.9.10 Viewer software shall allow the adjustment of thecontr
49、ast (window width) of the production image. Contrastadjustment of the production image may direct the contrast ofTABLE 1 Digital Reference Images for Aluminum CastingsDiscontinuity CastingThickness in.AApplicable CastingThickness in.AGas holes14 up to12 , inclGas holes34 over12 to 2, inclGas porosity (round)14 up to12 , inclGas porosity (round)34 over12 to 2, inclGas porosity (elongated)14 up to12 , inclGas porosity (elongated)34 over12 to 2, inclShrinkage cavity14 All thicknessesShrinkage (sponge)14 up to12 , inclShrinkage (sponge)34 over12
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