ASTM E2422-2005 Standard Digital Reference Images for Inspection of Aluminum Castings《检验铝铸件的标准数字参考图像》.pdf

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1、Designation: E 2422 05Standard Digital Reference Images forInspection of Aluminum Castings1This standard is issued under the fixed designation E 2422; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num

2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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. Scope1.1 These digital reference images illustrate the types andd

3、egrees 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 the

4、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.1.4 These digital reference images are not intended toillustrate the types and degrees of discontinuities found inaluminum-a

5、lloy castings when performing film radiography. Ifperforming film radiography of aluminum-alloy castings, referto Reference Radiographs E 155.1.5 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

6、 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 the software and images shall beutilized for production inspection. A copy of the ASTM/Userlicense agreement shall be kept on file for audit purp

7、oses.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 andcontain an image of a step wedge and two line pair gauges. Refer toPractice

8、E 2002 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 contained inReference Radiographs E 505.2. Referenced Documents2.1 ASTM Standards:2E94 Guide for Radiographic ExaminationE 155 Reference Radiographs fo

9、r Inspection of Aluminumand Magnesium CastingsE 505 Reference Radiographs for Inspection of Aluminumand Magnesium Die CastingsE 1316 Terminology for Nondestructive TestingE 2002 Practice for Determining Total Image Unsharpnessin Radiology2.2 SMPTE Practice:3RP133 SMPTE Recommended Practice Specifica

10、tions 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 E 1316.3.2 Definit

11、ions 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 iscapable of repr

12、oducing. 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 image thatmakes the change in digital driving level versus change inthickness equal for both images.1This st

13、andard 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 October 1, 2005. Published November 2005.2For referenced ASTM standards, visit the ASTM website, www.astm

14、.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 Television Engineers, 3 BarkerAvenue White Plains, NY 10601; or http:/www.smpte

15、.org/smpte_store/4Available from ASTM International Headquarters. Order Reference Radio-graph No. RRE2422.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.4 DDLdigital driving level also known as monitorpixel value.3.2.5 foreign m

16、aterialsappear 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.3.2.6 gas holesappear as round or elongated, smooth-edge

17、d 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 through the entire casting.3.2.8 measured resolutionthe chara

18、cteristic resolution ofa digital 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)alocalized lacy or honeycombed darkened area in a negati

19、veimage.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, whichmay be developed for particular requirements, can be

20、 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 in thethickness range up to and including12-in. 12.7 mm.

21、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 images. Forexample, electrical interference, hardware incompatibi

22、lities,and corrupted files or drivers may affect their appearance. TheASTM E 2002 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 measured resolutionusing the gauges to the resolution stated on the d

23、igital 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-neering organization and the supplier that the system used byth

24、e 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 digital reference images as acceptance standardsshould be base

25、d 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 area shall meet the require-ments as defined for acceptability.5.

26、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 be speci-fied for different regions or zones of a component.5.1

27、.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 Production digital images containing porosity, gas orinclusions may be

28、 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 applicable), theacceptance severity level for each discontinuity type,

29、 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. It is advisable to consult with themanufacturer/foundry befor

30、e 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 Perform the contrast normalization (window width nor-malization) between the production image and the referenceimage.6.3 Once co

31、ntrast normalization has been performed, con-trast (window width) shall not be altered in either imagewithout re-performing contrast normalization prior to productevaluation.7. Description7.1 The digital reference images listed in Table 1 illustrate5A study was performed that compared film to digita

32、l modalities for theclassification of aluminum casting discontinuities. Results of this study are availablefrom ASTM as RR: E07-1004.TABLE 1 Digital Reference Images for Aluminum CastingsDiscontinuity CastingThickness in.AApplicable CastingThickness in.AGas holes14 up to12 , inclGas holes34 over12 t

33、o 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 to 2, inclForeign material (less

34、 dense)14 up to12 , inclForeign material (less dense)34 over12 to 2, inclForeign material (more dense)14 up to12 , inclForeign material (more dense)34 over12 to 2, inclA1 in. = 25.4 mm.E2422052each type of discontinuity in eight grades. Although eightgrades of each discontinuity are shown, a numeric

35、ally smallergraded set of discontinuities based on these digital referenceimages could be used for acceptance standards. The radio-graphic technique used is in agreement with Guide E94.7.2 The alloys used to reproduce the various discontinuitiesare as listed in Table 2.7.3 The step wedges shown in t

36、he 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 arenot illustrated, as they are readily identifiable by surface inspection or byother means of nondestructive testing.8. Digital Imag

37、e 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 installation unless instructed otherwise during the loadprocess.8.3 The software will require the user

38、 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 digitalreference image resolution to be specified to the nearest10-micron increment. Select the reso

39、lution 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 detector resolution as follows:8.5.1 Use the ASTM E 2002 unsharpness gauge to deter-mine the measured spatial res

40、olution.8.5.2 Measurements shall be taken approximately five de-grees from the vertical orientation and approximately fivedegrees from the horizontal orientation.8.5.3 Position the gauge directly on the detector.8.5.4 Use a focal spot size and focal detector distancetypical of production conditions.

41、8.5.5 Using the line profile tool, take line profile statisticsperpendicular to the wire pairs.8.5.6 Select the first wire pair that displays a dip betweenthe wires of less than 20 %.8.5.7 Select the wire pair results with the highest unsharp-ness value.8.5.8 Determine the measured resolution. The m

42、easuredresolution is one-half of the measured unsharpness. Refer toPractice E 2002 to determine wire pair corresponding unsharp-ness values.8.5.9 Compare the measured resolution to the theoreticalresolution determined by pixel size. If the measured resolutiondiffers by no more than 30 % from the the

43、oretical resolutionuse the theoretical resolution as the detector resolution.8.5.10 If the measured resolution 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 scan

44、index.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. Thisaverage value is then the pixel value for the pixels of the same size andlocation as the su

45、bject bins.9. Viewer Software Requirements9.1 Viewer software shall be capable of importing thedigital reference images as either a 16-bit grayscale uncom-pressed single strip TIFF format or in the DICONDE format.9.2 Viewer software shall be capable of importing andstoring digital reference images a

46、t 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 possible to view production and digitalreference images simultaneously on a s

47、ingle monitor or op-tionally, on several monitors that are matched to provide equalbrightness for a given digital driving level.9.5 Viewer software shall provide a contrast normalizationfeature that will allow for the normalization of contrastbetween a production digital image and a reference image,

48、when both exposures have step wedges of AL 6061 aluminumcovering the thickness range of the area of interest. Thenormalization will be such that the change in gray scale versuschange in thickness will be the same in both images.9.6 Viewer software shall provide the capability to lock thezoom levels

49、of the production and reference digital images, sothat both images are simultaneously adjusted.9.7 Viewer software shall be capable of 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 thecontrast (window width) of the production image. Contrastadjustment of the production image shall di