1、Designation:E286913Standard Digital Reference Images forMagnesium Castings1This standard is issued under the fixed designation E2869;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 parentheses in
2、dicates 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 the types anddegrees of discontinuities that may be found in magnesium-alloy castings.The castings illustrated are in thi
3、cknesses of14in.(6 mm)and34in.(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 purchaseorder or the contract.1.3 The
4、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 toillustrate the types and degrees of disc
5、ontinuities found inmagnesium-alloy castings when performing film radiography.If performing film radiography of magnesium-alloy castings,refer to Reference Radiographs E155.1.5 Only licensed copies of the software and images shall beutilized for production examination.Acopy of theASTM/Userlicense ag
6、reement shall be kept on file for audit purposes.NOTE1The set of digital reference images consists of 14 digital files,software to load the desired format and specific instructions on the loadingprocess.The 14 reference images illustrate eight grades of severity andcontain an image of a step wedge a
7、nd two duplex wire gauges.1.6 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 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior
8、 to use.2.Referenced Documents2.1 ASTM Standards:2E155 Reference Radiographs for Inspection of Aluminumand Magnesium CastingsE1316 Terminology for Nondestructive ExaminationsE2002 Practice for Determining Total Image Unsharpness inRadiologyE2446 Practice for Classification of Computed RadiologySyste
9、msE2597 Practice for Manufacturing Characterization of Digi-tal Detector Arrays2.2 SMPTE Practice3RP133 SMPTE Recommended Practice Specifications forMedical Diagnostic Imaging Test Pattern for TelevisionMonitors and Hard-Copy Recording Cameras2.3 ASTM Adjuncts4Digital Reference Images for Magnesium
10、Castings3.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 described based upon radiologicalappearance.(See No
11、te 2.)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.3.2.3 contrast normalizationthe adjustment of contrastbetween the producti
12、on image and the reference image 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.1This standard is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct r
13、esponsibility of Subcommittee E07.02 onReference Radiological Images.Current edition approved June 1,2013.Published August 2013.DOI:10.1520/E286913.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards v
14、olume 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.org/smpte_store/4Available from ASTM International Headquarters.Order Adjunct No.RRE2869.Origin
15、al adjunct produced in 2013.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.5 foreign materialsappear as isolated,irregular,orelongated variations in brightness,not corresponding to varia-tions in thickness of material,nor to cavities
16、.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 porosityrepresented 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 of adigital radiographic system as mea
