ASTM E690-1998(2004)e1 Standard Practice for In Situ Electromagnetic (Eddy-Current) Examination of Nonmagnetic Heat Exchanger Tubes《无磁热交换管的现场电磁(涡电流)检验》.pdf
《ASTM E690-1998(2004)e1 Standard Practice for In Situ Electromagnetic (Eddy-Current) Examination of Nonmagnetic Heat Exchanger Tubes《无磁热交换管的现场电磁(涡电流)检验》.pdf》由会员分享,可在线阅读,更多相关《ASTM E690-1998(2004)e1 Standard Practice for In Situ Electromagnetic (Eddy-Current) Examination of Nonmagnetic Heat Exchanger Tubes《无磁热交换管的现场电磁(涡电流)检验》.pdf(4页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: E 690 98 (Reapproved 2004)e1Standard Practice forIn Situ Electromagnetic (Eddy-Current) Examination ofNonmagnetic Heat Exchanger Tubes1This standard is issued under the fixed designation E 690; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorial changes made throughout in January 2004.1. Scope1.1 This practice describes p
3、rocedures to be followed duringeddy-current examination (using an internal, probe-type, coilassembly) of nonmagnetic tubing that has been installed in aheat exchanger. The procedure recognizes both the uniqueproblems of implementing an eddy-current examination ofinstalled tubing, and the indigenous
4、forms of tube-wall dete-rioration which may occur during this type of service. Thedocument primarily addresses scheduled maintenance inspec-tion of heat exchangers, but can also be used by manufacturersof heat exchangers, either to examine the condition of the tubesafter installation, or to establis
5、h baseline data for evaluatingsubsequent performance of the product after exposure tovarious environmental conditions. The ultimate purpose is thedetection and evaluation of particular types of tube integritydegradation which could result in in-service tube failures.1.2 This practice does not establ
6、ish acceptance criteria; theymust be specified by the using parties.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 a
7、pplica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E 543 Practice for Evaluating Agencies that Perform Non-destructive TestingE 1316 Terminology for Nondestructive Examinations2.2 Other Documents:SNT-TC-1A Recommended Practice for Personnel Qualifi-cation
8、 and Certification in Nondestructive Testing3ANSI/ASNT-CP-189 ASNT Standard for Qualification andCertification of Nondestructive Testing Personnel3NAS-410 NAS Certification and Qualification of Nonde-structive Personnel (Quality Assurance Committee)43. Terminology3.1 Standard terminology relating to
9、 electromagnetic ex-amination may be found in Terminology E 1316, Section C,Electromagnetic Testing.4. Summary of Practice4.1 The examination is performed by passing an eddy-current probe through each tube. These probes are energizedwith alternating currents at one or more frequencies. Theelectrical
10、 impedance of the probe is modified by the proximityof the tube, the tube dimensions, electrical conductivity,magnetic permeability, and metallurgical or mechanical dis-continuities in the tube. During passage through the tube,changes in electromagnetic response caused by these variablesin the tube
11、produce electrical signals which are processed so asto produce an appropriate combination of visual displays,alarms, or temporary or permanent records, or combinationthereof, for subsequent analysis.NOTE 1The agency performing the testing or examination shall meetthe requirements of Practice E 543.5
12、. Significance and Use5.1 Eddy-current examination is a nondestructive method oflocating discontinuities in tubing made of materials thatconduct electricity. Signals can be produced by discontinuitieslocated either on the inner or outer surfaces of the tube, or bydiscontinuities totally contained wi
13、thin the tube wall. Whenusing an internal probe, the density of eddy currents in the tube1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.07 onElectromagnetic Methods.Current edition approved January 1, 200
14、4. Published February 2004. Originallyapproved in 1979. Last previous edition approved in 1998 as E 690 98.2For 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 stand
15、ards Document Summary page onthe ASTM website.3Available from The American Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518.4Available from Aerospace Industries Association of America, Inc., 1250 EyeStreet, N.W., Washington, DC 20005.1Copyright AS
16、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.wall decreases very rapidly as the distance from the internalsurface increases; thus the amplitude of the response to outersurface discontinuities decreases correspondingly.5.2 Some indications obta
17、ined by this method may not berelevant to product quality. For example, an irrelevant signalmay be caused by metallurgical or mechanical variations thatare generated during manufacture but that are not detrimentalto the end use of the product. Irrelevant indications can maskunacceptable discontinuit
18、ies occurring in the same area. Rel-evant indications are those that result from nonacceptablediscontinuities. Any indication above the reject level, which isbelieved to be irrelevant, shall be regarded as unacceptableuntil it is proven to be irrelevant. For tubing installed in heatexchangers, predi
19、ctable sources of irrelevant indications arelands (short unfinned sections in finned tubing), dents,scratches, tool chatter marks, or variations in cold work.Rolling tubes into the supports may also cause irrelevantindications, as may the tube supports themselves. Eddy-currentexamination systems are
20、 generally not able to separate theindication generated by the end of the tube from indications ofdiscontinuities adjacent to the ends of the tube (end effect).Therefore, this examination may not be valid at the boundariesof the tube sheets.6. Basis of Application6.1 The following criteria may be sp
21、ecified in the purchasespecification, contractual agreement, or elsewhere, and mayrequire agreement between the purchaser and the supplier.6.1.1 Type of eddy-current system, and probe (coil assem-bly) configuration,6.1.2 Location of heat exchanger, if applicable,6.1.3 Size, material, and configurati
22、on of tubes to be exam-ined,6.1.4 Extent of examination, that is, length, tube sheet areas,straight length only, minimum radius of bends, etc.,6.1.5 Time of examination, that is, the date and location ofthe intended examination, and the expected environmentalconditions,6.1.6 The source and type of m
23、aterial to be used forfabricating the reference standard,6.1.7 The type(s), method of manufacture, location, dimen-sions, and number of artificial discontinuities to be placed onthe reference standard,6.1.8 Allowable tolerances for artificial discontinuities, andmethods for verifying compliance,6.1.
24、9 Methods for determining the extent of end effect,6.1.10 Maximum time interval between equipment refer-ence checks,6.1.11 Criteria to be used in interpreting and classifyingobserved indications,6.1.12 Disposition of examination records and referencestandard,6.1.13 Contents of examination report, an
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