1、Designation:E181414Standard Practice forComputed Tomographic(CT)Examination of Castings1This standard is issued under the fixed designation E1814;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 p
2、arentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This practice covers a uniform procedure for the exami-nation of castings by the computed tomography(CT)tech-nique.The requirements expressed in this
3、 practice are intendedto control the quality of the nondestructive examination by CTand are not intended for controlling the acceptability or qualityof the castings.This practice implicitly suggests the use ofpenetrating radiation,specifically X rays and gamma rays.1.2 This practice provides a unifo
4、rm procedure for a CTexamination of castings for one or more of the followingpurposes:1.2.1 Examining for discontinuities,such as porosity,inclusions,cracks,and shrink;1.2.2 Performing metrological measurements and determin-ing dimensional conformance;and1.2.3 Determining reverse engineering data,th
5、at is,creatingcomputer-aided design(CAD)data files.1.3 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 reg
6、ulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing NondestructiveTestingE1316 Terminology for Nondestructive ExaminationsE1441 Guide for Computed Tomography(CT)ImagingE1570 Practice for Computed Tomographic(CT)Examina-tionE1672 Guide
7、 for Computed Tomography(CT)System Se-lectionE1695 Test Method for Measurement of Computed Tomog-raphy(CT)System PerformanceE1935 Test Method for Calibrating and Measuring CTDensityE2339 Practice for Digital Imaging and Communication inNondestructive Evaluation(DICONDE)E2767 Practice for Digital Ima
8、ging and Communication inNondestructive Evaluation(DICONDE)for X-ray Com-puted Tomography(CT)Test Methods2.2 ASNT Documents:3SNT-TC-1A Recommended Practice for Personnel Qualifi-cation and Certification in Nondestructive TestingANSI/ASNT CP-189 Standard for Personnel Qualificationand Certification o
9、f Nondestructive Testing Personnel2.3 Military Standards:4NAS 410 Certification and Qualification of NondestructiveTest Personnel3.Terminology3.1 DefinitionsDefinitions of terms applicable to thispractice may be found in Terminology E1316 and GuideE1441.3.2 Definitions of Terms Specific to This Stan
10、dard:3.2.1 fixturingthe mounting hardware used to place theobject in the CT system.3.2.2 scan planscan locations and the system configura-tion parameters for a specific part examination.4.Significance and Use4.1 CT may be performed on an object when it is in theas-cast,intermediate,or final machined
11、 condition.A CTexamination can be used as a design tool to improve wax formsand moldings,establish process parameters,randomly checkprocess control,perform final quality control(QC)examina-tion for the acceptance or rejection of parts,and analyzefailures and extend component lifetimes.4.2 The most c
12、ommon applications of CT for castings arefor the following:locating and characterizing discontinuities,1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.01 onRadiology(X and Gamma)Method.Current edition appr
13、oved June 1,2014.Published June 2014.Originallyapproved in 1996.Last previous edition approved in 2007 as E1814-96(2007).DOI:10.1520/E1814-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume
14、information,refer to the standards Document Summary page onthe ASTM website.3Available fromAmerican Society for Nondestructive Testing(ASNT),P.O.Box28518,1711 Arlingate Ln.,Columbus,OH 43228-0518,http:/www.asnt.org.4Available from Standardization Documents Order Desk,DODSSP,Bldg.4,SectionD,700Robbin
15、sAve.,Philadelphia,PA19111-5098,http:/assist.daps.dla.mil.*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 States1 such as porosity,inclusions,cracks,and shrink;measuringas-cast part
16、 dimensions for comparison with design dimen-sions;and extracting dimensional measurements for reverseengineering.4.3 The extent to which a CT image reproduces an object ora feature within an object is dictated largely by the competinginfluences of spatial resolution,contrast discrimination,thespecific geometry and material of the object itself,and artifactsof the imaging system.Operating parameters strike an overallbalance between image quality,examination time,and cost.4.4 Artifacts are often
