ASTM_E_1962_-_14.pdf

Designation:E196214Standard Practice forUltrasonic Surface Testing Using Electromagnetic AcousticTransducer(EMAT)Techniques1This standard is issued under the fixed designation E1962;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 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 guidelines for utilizing EMATtechniques for detecting material discontinuities that are pri-marily open to the surface(for example,cracks,seams,laps,cold shuts,laminations,through leaks,lack of fusion).Thistechnique can also be sensitive to flaws and discontinuities thatare not surface-breaking,provided their proximity to thesurface is less than or equal to the Rayleigh wave length.1.2 This practice covers procedures for the non-contactcoupling of surface waves into a material via electromagneticfields.1.3 The procedures of this practice are applicable to anymaterial in which acoustic waves can be introduced electro-magnetically.This includes any material that is either electri-cally conductive or ferromagnetic,or both.1.4 This practice is intended to provide examination capa-bilities for in-process,final,and maintenance applications.1.5 This practice does not provide standards for the evalu-ation of derived indications.Interpretation,classification,andultimate evaluation of indications,albeit necessary,are beyondthe scope of this practice.Separate specifications or agreementwill be necessary to define the type,size,location,anddirection of indications considered acceptable or non-acceptable.1.6 The values stated in inch-pound units are to be regardedas the standards.The SI units given in parentheses are forinformation only.1.7 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 to use.2.Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing NondestructiveTestingE587 Practice for Ultrasonic Angle-Beam Contact TestingE1316 Terminology for Nondestructive ExaminationsE1774 Guide for Electromagnetic Acoustic Transducers(EMATs)E1816 Practice for Ultrasonic Testing Using Electromag-netic Acoustic Transducer(EMAT)Techniques2.2 ANSI/ASNT Standards:Recommended Practice SNT-TC-1A Personnel Qualifica-tion and Certification in Nondestructive Testing3ANSI/ASNT CP-189 Standard for Qualification and Certifi-cation of Nondestructive Testing Personnel32.3 Military Standard:MIL-STD-410 Nondestructive Testing Personnel Qualifica-tion and Certification43.Terminology3.1 Definitions:3.1.1 Additional related terminology is defined in Terminol-ogy E1316.3.2 Definitions of Terms Specific to This Standard:3.2.1 electromagnetic acoustic transducer(EMAT)anelectromagnetic device for converting electrical energy intoacoustical energy in the presence of a magnetic field.3.2.2 Lorentz forcesapplied to electric currents whenplaced in a magnetic field.Lorentz forces are perpendicular toboth the direction of the magnetic field and the currentdirection.3.2.3 magnetostrictive forcesforces arising from magneticdomain wall movements within a magnetic material during1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.06 onUltrasonic Method.Current edition approved Oct.1,2014.Published October 2014.Originallyapproved in 1998.Last previous edition approved in 2009 as E1962-09.DOI:10.1520/E1962-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Available from U.S.Government Printing Office Superintendent of Documents,732 N.Capitol St.,NW,Mail Stop:SDE,Washington,DC 20401.*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 magnetization,where magnetostrictive materials will undergoa strain in the presence of a magnetic field.3.2.4 meander coilan EMAT coil consisting of periodic,winding,non-intersecting,and usually evenly-spaced conduc-tors.4.Summary of Practice4.1 The techniques outlined in this practice address theelectromagnetic generation of Rayleigh acoustic wave modesfor sensitivity to surface or near-surface flaws or discontinui-ties.Flaws are detected by reflection or attenuation of acousticwaves from interactions at discontinuity interfaces.4.2 Fig.1 shows one typical EMAT setup for the gen