1、Designation: E2669 161Standard Digital Reference Images forTitanium Castings1This standard is issued under the fixed designation E2669; 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 parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEThe designation for Volume I of the Reference Radiographs was corrected editorially in October 2016.1. Scope*1.1 The digital reference images provided in the ad
3、juncts tothis standard illustrate various types and degrees of disconti-nuities occurring in titanium castings.2Use of this standard forthe specification or grading of castings requires procurement ofthe appropriate adjunct digital reference images, which illus-trate the discontinuity types and seve
4、rity levels. They areintended to provide the following:1.1.1 A guide enabling recognition of titanium castingdiscontinuities and their differentiation both as to type anddegree through digital radiographic examination.1.1.2 Example digital radiographic illustrations of disconti-nuities and a nomencl
5、ature for reference in acceptancestandards, specifications and drawings.1.2 The digital reference images consist of twenty-fivedigital files each illustrating eight grades of increasing severity.The Volume I files illustrate seven common discontinuity typesrepresenting casting sections up to 1 in. (
6、25.4 mm). TheVolume II files illustrate five discontinuity types representingcasting sections over 1 in. (25.4 mm) to 2 in. (50.8 mm) inthickness.1.3 All areas of this standard may be open to agreementbetween the cognizant engineering organization and thesupplier, or specific direction from the cogn
7、izant engineeringorganization. These items should be addressed in the purchaseorder or the contract.NOTE 1The digital reference images are available from ASTMInternational Headquarters. Order number RRE2669 and RRE266902.Each of the digital reference images contain an image of a step densityscale an
8、d two duplex-wire gauges. Refer to Practice E2002 for wire pairdetails. Originally, only Volume I images were available and some setsmay identify these only as RRE2669 without a volume designation. Theyremain valid for use as Volume I images.1.4 The values stated in inch-pound units are to be regard
9、edas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 These digital reference images are not intended toillustrate the types or degrees of discontinuities when perform-ing film radiography. If
10、performing film radiography of tita-nium castings, refer to Reference Radiographs E1320.1.6 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
11、 and determine the applica-bility of regulatory limitations prior to use.1.7 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 purposes.2. Referenced Documents2.1 ASTM Standards:3E1316
12、Terminology for Nondestructive ExaminationsE1320 Reference Radiographs for Titanium CastingsE2002 Practice for Determining Total Image Unsharpnessand Basic Spatial Resolution in Radiography and Radios-copy2.2 SMPTE Practice:4RP1332.3 ASTM Adjuncts:Digital Reference Images for Titanium Castings:Volum
13、e I:Applicable for Thicknesses up to 1 in. (25.4 mm)5Volume II: Applicable for Thicknesses over 1 in. (25.4 mm)to 2 in. (50.8 mm)61This standard is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.02 onReference Radiological
14、 Images.Current edition approved June 1, 2016. Published June 2016. Originallyapproved in 2010. Last previous edition approved in 2011 as E2669 - 11.DOI:10.1520/E2669-16.2The digital reference images are considered to be applicable to all titaniumcastings, requiring close tolerances. Castings for wh
15、ich these images are applicablegenerally include those made by the lost wax, frozen mercury, ceramicast or shellmold processes.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information
16、, refer to the standards Document Summary page onthe ASTM website.4Available from Society of Motion Picture and Television Engineers, 3 BarkerAvenue, White Plains, NY 10601; or www.smpte.org/smpte_store/5Available from ASTM International Headquarters. Order Adjunct No.RRE2669.6Available from ASTM In
17、ternational Headquarters. Order Adjunct No.RRE266902.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 DefinitionsDefinitions of terms used in this stand
18、ardmay 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 radiographicappearance when viewed in the negative polarity such that theimages appear in the same sense
19、as they would when viewedon X-ray film. If images are viewed in the positive polarity, theterms lighter and darker will need to be reversed.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 appea
20、r 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.3.2.4 DDLdigital driving level also kn
21、own as monitorpixel value.3.2.5 system resolutionthe detector-measured resolutiondivided by the geometric magnification.3.2.6 gasGas in its various forms is usually caused by thereaction of molten titanium with the mold or residual materialleft in the mold. Gas tends to migrate to the upper portions
22、 ofthe casting. The formation of clustered or scattered gas holesresults from the generation of larger amounts of gas than asingle gas hole. Whether the larger amount of gas spreads outor is confined to a small area is dependent upon a number offactors including casting process, reaction area, solid
23、ificationrate, wall thickness, and geometry.3.2.6.1 gas holesspherical voids formed through the re-lease and subsequent entrapment of gas during solidification.Agas hole will appear as a dark round spot on the digital image.3.2.6.2 clustered gas holesa closely nested group of darkround voids concent
24、rated within a self-defined boundary area.3.2.6.3 scattered gas holesmultiple voids appearing asdark round spots on the digital image. They are randomlyspread throughout a part or area of a part to a lesser concen-tration than clustered gas holes but with the potential todegrade the casting through
25、their interaction which precludestheir evaluation on an individual basis.3.2.7 shrinkageWhile at times the appearance of shrink-age in titanium may be radiographically similar to shrinkage insteel, the faster solidification rate of titanium has a dramaticeffect on the conditions under which each shr
26、inkage type willoccur in titanium. Other factors which influence the formationof shrinkage are wall thickness and thickness transitiongradients, gate size and orientation, mold design, castingconfiguration, metal/mold temperature, and pouring rate andmethod.All the types of shrinkage described in 3.
27、2.7.1 through3.2.7.3 have a degree of overlap. However, each is most likelyto occur under a specific set of conditions primarily influencedby metal feed, section thickness and cooling rate.3.2.7.1 shrinkage cavityappears as a dark void withsmooth sides taking an appearance very similar to a gas hole
28、.A shrinkage cavity, particularly in thicker wall sections, isusually larger than a single gas hole would be. The cavity isformed during the cooling process due to a lack of feedingmetal. The cavity compensates for the rapid solidificationtaking place at the surface of the casting, thereby forming t
29、hecavity in the center area of the wall. Shrinkage cavity has adefinite tendency to occur near hot spots where walls are12-in.(12.7-mm) thick or more.3.2.7.2 scattered shrinkageappears on a digital image asdark fine lacy or filamentary voids of varying densities. Thesevoids are usually uniformly spr
30、ead throughout the area of thecasting where shrinkage is occurring and are relatively shallow.3.2.7.3 shrinkage, centerlinecharacterized by a more dis-crete dark indication than scattered shrinkage. The indicationhas definite borders consisting of a lacy network of varyingdensity or a network of int
31、erconnected elongated voids. Cen-terline shrinkage is located primarily in the center of thematerial cross section with a tendency to orient toward gates orrisers.3.2.8 foreign material, less denseappear as dark indica-tions in a variety of shapes and sizes on a digital image.Inclusions may be found
32、 in groups or appear singularly. Lessdense inclusions can be caused by contaminants in the moltentitanium, residual materials left on the surface of the mold, orbroken pieces of the mold becoming entrapped during solidi-fication.3.2.9 foreign material, more denseappear as light indica-tions in a var
33、iety of shapes and sizes on a digital image. Moredense inclusions can be caused by contaminants introduced inthe same manner as less dense inclusions, or tungsten intro-duced during weld repairs.4. Significance and Use74.1 These digital reference images are intended for refer-ence only, but are desi
34、gned such that acceptance standards,which may be developed for particular requirements, can bespecified in terms of these digital reference images. Theillustrations are digital images of castings that were producedunder conditions designed to develop the discontinuities.4.1.1 Applicability of Thickn
35、ess Designations:4.1.1.1 The discontinuity types, illustrated thickness andapplicable thickness range are summarized in Table 1 for theVolume I images and in Table 2 for the Volume II images.4.2 Image DeteriorationMany conditions can affect theappearance and functionality of digital reference images
36、. Forexample, electrical interference, hardware incompatibilities,and corrupted files and drivers may affect their appearance. ThePractice E2002 line pair gauges located in each digital refer-ence image can be used as an aid to detect image deteriorationby comparing the measured resolution using the
37、 gauges to theresolution stated on the digital reference image. Do not use the7A 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. A subsequent study was performed that
38、comparedfilm to digital modalities for the classification of titanium and steel castingdiscontinuities. Results of this study are available from ASTM as RR:E07-1006.E2669 1612digital reference images if their appearance has been adverselyaffected such that the interpretation and use of the images co
39、uldbe 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 of Application5.1 The digital reference images may be applied as accep-tance
40、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 2).5.1.1 An area of like size to that of the digital referenceimage shall be the unit a
41、reas 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 application.Different grades or acceptance limits may be s
42、pecified 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. Anymodifications to the acceptance criteria required on
43、the basis ofmultiple discontinuity types must be specified.5.1.4 Production digital images containing gas or inclusionsmay be rated by the overall condition with regard to size,number, and distribution. These factors should be considered inbalance.5.1.5 As a minimum, the acceptance criteria should c
44、ontaininformation 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 2Caution should be exercised in specifying the acceptancecriteria to be met in a casting. Cast
45、ing 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 Evaluation6.1 Select the appropriate digital reference image.6.2 Apply
46、 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 and Table2 illustrate each type of graded discontinuity in eight grades.Although eight
47、grades of each discontinuity are shown, anumerically smaller graded set of discontinuities based onthese digital reference images could be used for acceptancestandards.7.2 The step wedges shown in the Volume I digital referenceimages are made of Titanium 6 Al 4V with the step thicknesseslisted in Ta
48、ble 3. The Volume II images utilize a steppeddensity scale rather than a radiograph of a physical step wedge.TABLE 1 Volume I Digital Reference Images for Titanium Castings up to 1 in. 25.4 mmDiscontinuity Casting Process Alloy Plate Thickness, in. Applicable Casting Thickness, in.Gas hole Centrifug
49、al ram graphite Ti 6AL 4V N/A Up to 1Clustered gas holes Centrifugal precision Ti 6AL 4V14 Up to38Clustered gas holes Centrifugal precision Ti 6AL 4V12 Over38 to58Clustered gas holes Centrifugal precision Ti 6AL 4V34 Over58 to 1Scattered gas holes Top pour lost wax Ti 6AL 4V14 Up to38Scattered gas holes Top pour lost wax Ti 6AL 4V12 Over38 to58Scattered gas holes Top pour lost wax Ti 6AL 4V34 Over58 to 1Shrinkage cavity Centrifugal ram graphite Ti 6AL 4V12 Over14 to58Shrinkage cavity Centrifugal ram graphite Ti 6AL 4V34 Over58 to 1Scattered
