1、Designation:E131209(Reapproved 2013)1Standard Practice forElectromagnetic(Eddy Current)Examination ofFerromagnetic Cylindrical Bar Product Above the CurieTemperature1This standard is issued under the fixed designation E1312;the number immediately following the designation indicates the year oforigin
2、al adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1NOTEChanges were made editorially in July 2013.1.Scope*1.1 This practice covers pr
3、ocedures for eddy current exami-nation of hot ferromagnetic bars above the Curie temperaturewhere the product is essentially nonmagnetic,but below2100 F(1149 C).1.2 This practice is intended for use on bar products havingdiameters of12in.(12.7 mm)to 8 in.(203 mm)at linearthroughput speeds up to 1200
4、 ft/min(366 m/min).Larger orsmaller diameters may be examined by agreement between theusing parties.1.3 The purpose of this practice is to provide a procedure forin-line eddy current examination of bars during processing forthe detection of major or gross surface discontinuities.1.3.1 The types of d
5、iscontinuities capable of being detectedare commonly referred to as:slivers,laps,seams,roll-ins(scale,dross,and so forth),and mechanical damage such asscratches,scores,or indentations.1.4 This practice does not establish acceptance criteria.They must be specified by agreement between the usingpartie
6、s.1.5 The 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.1.6 This practice does not purport to address all of thesafety concerns,if any,assoc
7、iated with its use.It is theresponsibility of the user of this practice to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing NondestructiveTes
8、tingE1316 Terminology for Nondestructive Examinations2.2 Other Documents:SNT-TC-1A Recommended Practice for Personnel Qualifi-cation and Certification in Nondestructive Testing3ANSI/ASNT-CP-189 Standard for Qualification and Certifi-cation of NDT Personnel32.3 AIA Standard:NAS 410 Certification and
9、Qualification of NondestructiveTesting Personnel43.Terminology3.1 Standard terminology relating to electromagnetic testingmay be found in Terminology E1316,Section C:Electromag-netic Testing.4.Summary of Practice4.1 PrincipleThe major advantage of examining ferro-magnetic bar product above the Curie
10、 temperature with eddycurrents is the enhanced signal-to-noise ratio obtained withoutthe need for magnetic saturation.4.2 SensorsThis examination may be performed withvarious types or designs of encircling coils or with probe coilsthat are fixed or rotating.4.2.1 One or more exciter or sensor coils
11、is used to encirclethe bar through which the product to be examined is passed.When the hot bar is in close proximity to the sensing and1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.07 onElectromagnetic M
12、ethod.Current edition approved July 15,2013.Published August 2013.Originallyapproved in 1989.Last previous edition approved in 2009 as E1312 09.DOI:10.1520/E1312-09R13E01.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual
13、Book of ASTMStandards volume 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 Aerospace Industries Association of Amer
14、ica,Inc.(AIA),1000Wilson Blvd.,Suite 1700,Arlington,VA22209-3928,http:/www.aia-aerospace.org.*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 exciting coils,eddy currents are
15、 induced in the hot product byan alternating current.The sensing coil detects the electromag-netic flux related to these currents.Changes or disruptions inthe normal flux pattern indicate the presence of discontinuities.This technique is capable of examining the entire circumfer-ence without contact
16、ing the product.4.2.2 The surface can also be examined with probe coilshaving one or more exciters and sensors which are spaced inclose proximity to the product surface.The probe is usuallysmall and does not encircle the product,making it necessary torotate either the probes or the product to obtain 100%coverageof the circumference.This is essentially a contact techniquebecause the coil is fixtured in a device that rides on thecircumference to maintain a fixed distance between the coil andproduc