ASTM_E_2337_-_E_2337M_-_10_2015.pdf

Designation:E2337/E2337M10(Reapproved 2015)Standard Guide forMutual Inductance Bridge Applications for Wall ThicknessDeterminations in Boiler Tubing1This standard is issued under the fixed designation E2337/E2337M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide describes a procedure for obtaining relativewall thickness indications in ferromagnetic and non-ferromagnetic steels using the mutual inductance bridgemethod.The procedure is intended for use with instrumentscapable of inducing two substantially identical magnetic fieldsand noting the change in inductance resulting from differingamounts of steel.It is used to distinguish acceptable wallthickness conditions from those which could place tubularvessels or piping at risk of bursting under high temperature andpressure conditions.1.2 This guide is intended to satisfy two general needs forusers of industrial Mutual Inductance Bridge(MIB)equip-ment:(1)the need for a tutorial guide addressing the generalprinciples of Mutual Inductance Bridges as they apply toindustrial piping;and(2)the need for a consistent set of MIBperformance parameter definitions,including how these per-formance parameters relate to MIB system specifications.Potential users and buyers,as well as experienced MIBexaminers,will find this guide a useful source of informationfor determining the suitability of MIB for particular examina-tion problems,for predicting MIB system performance in newsituations,and for developing and prescribing new scan pro-cedures.1.3 This guide does not specify test objects and test proce-dures for comparing the relative performance of different MIBsystems;nor does it treat electromagnetic examinationtechniques,such as the best selection of scan parameters,thepreferred implementation of scan procedures,the analysis ofimage data to extract wall thickness information,or theestablishment of accept/reject criteria for a new object.1.4 Standard practices and methods are not within thepurview of this guide.The reader is advised,however,thatexamination practices are generally part and applicationspecific,and industrial MIB usage is new enough that in manyinstances a consensus has not yet emerged.The situation iscomplicated further by the fact that MIB system hardware andperformance capabilities are still undergoing significant evo-lution and improvement.Consequently,an attempt to addressgeneric examination procedures is eschewed in favor ofproviding a thorough treatment of the principles by whichexamination methods can be developed or existing onesrevised.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.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 and determine the applica-bility of regulatory requirements prior to use.2.Referenced Documents2.1 ASTM Standards:2E1316 Terminology for Nondestructive Examinations3.Terminology3.1 DefinitionsThe definitions of terms relating to conven-tional magnetic examination methods can be found in Termi-nology E1316.3.2 Definitions of Terms Specific to This Standard:3.2.1 inductancethe property of an electric circuit ordevice whereby an electromotive force is created by a changeof current in it or in a circuit near it.3.2.2 mutual inductancethe electrical property of circuitsthat enables a current flowing in one conductor(or coil)toinduce a current in a nearby conductor(or coil).3.2.3 mutual inductance bridge(MIB)a nondestructiveexamination method,which employs a magnetic induction1This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-tive Testing and is the direct responsibility of Subcommittee E07.07 on Electro-magnetic Method.Current edition approved June 1,2015.Published June 2015.Originallyapproved in 2004.Last previous edition approved in 2010 as E2337-10.DOI:10.1520/E2337_E2337M-10R15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 method for the detection and assessment of variations of wallthickness in tubular vessels.In this procedure,an appropriatemagnetic field is first induced into two identical sections offerromagnetic or non-ferromagnet