EN 13860-2:2003
(Main)Non-destructive testing - Eddy current examination - Equipment characteristics and verification - Part 2: Probe characteristics and verification
Non-destructive testing - Eddy current examination - Equipment characteristics and verification - Part 2: Probe characteristics and verification
Migrated from Progress Sheet (TC Comment) (2000-07-10): WIs 086-088 = result of the splitting of WI 045 (TC Res 193/1998) (CC/981216)
Zerstörungsfreie Prüfung - Wirbelstromprüfung - Kenngrößen von Prüfeinrichtung und deren Verifizierung - Teil 2: Kenngrößen von Sensoren und deren Verifizierung
Essais non destructifs - Examen par courants de Foucault - Caractéristiques et vérification de l'appareillage - Partie 2: Caractéristiques du traducteur et vérifications
Neporušitveno preskušanje – Preiskave z vrtinčnimi tokovi – Karakteristike naprav in overjanje - 2. del: Karakteristike senzorjev in njihovo overjanje
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.QMHZerstörungsfreie Prüfung - Wirbelstromprüfung - Kenngrößen von Prüfeinrichtung und deren Verifizierung - Teil 2: Kenngrößen von Sensoren und deren VerifizierungEssais non destructifs - Examen par courants de Foucault - Caractéristiques et vérification de l'appareillage - Partie 2: Caractéristiques du traducteur et vérificationsNon-destructive testing - Eddy current examination - Equipment characteristics and verification - Part 2: Probe characteristics and verification19.100Neporušitveno preskušanjeNon-destructive testingICS:Ta slovenski standard je istoveten z:EN 13860-2:2003SIST EN 13860-2:2004en01-marec-2004SIST EN 13860-2:2004SLOVENSKI
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SIST EN 13860-2:2004
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13860-2February 2003ICS 19.100English versionNon-destructive testing - Eddy current examination - Equipmentcharacteristics and verification - Part 2: Probe characteristicsand verificationEssais non destructifs - Examen par courants de Foucault -Caractéristiques et vérification de l'appareillage - Partie 2:Caractéristiques du traducteur et vérificationsZerstörungsfreie Prüfung - Wirbelstromprüfung -Kenngrößen von Prüfeinrichtung und deren Verifizierung -Teil 2: Kenngrößen von Sensoren und deren VerifizierungThis European Standard was approved by CEN on 2 January 2003.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and UnitedKingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2003 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13860-2:2003 ESIST EN 13860-2:2004
EN 13860-2:2003 (E)2ContentspageForeword.31Scope.42Normative references.43Terms and definitions.44Probe and interconnecting elements characteristics.44.1General characteristics.44.2Electrical characteristics.64.3Functional characteristics.65Verification.75.1General.75.2Levels of verification.75.3Verification procedure.85.4Corrective actions.86Measurement of electrical and functional characteristics of a probe.86.1Electrical characteristics.86.2Functional characteristics.106.3Normalized impedance plane diagram.287Influence of interconnecting elements.28Annex A (informative)
Reference block A6.29A.1Nominal values and tolerances of characteristics.30A.2Manufacturing.30Bibliography.31SIST EN 13860-2:2004
EN 13860-2:2003 (E)3ForewordThis document (EN 13860-2:2003) has been prepared by CEN/TC 138 "Non-destructive testing", the secretariat ofwhich is held by AFNOR.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by August 2003, and conflicting national standards shall be withdrawn at the latest byAugust 2003.This European Standard has been prepared under a mandate given to CEN by the European Commission and theEuropean Free Trade Association.EN 13860 comprises a series of European Standards for "Eddy current examination - equipment" which is made upof the following:EN 13860-1Non-destructive testing - Eddy current examination - Equipment characteristics and verification -Part 1: Instrument characteristics and verification.EN 13860-2Non-destructive testing - Eddy current examination - Equipment characteristics and verification -Part 2: Probe characteristics and verification.prEN 13860-3Non-destructive testing - Eddy current examination - Equipment characteristics and verification -Part 3: System characteristics and verification.Annex A is informative.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,Slovakia, Spain, Sweden, Switzerland and the United Kingdom.SIST EN 13860-2:2004
EN 13860-2:2003 (E)41 ScopeThis European Standard identifies the functional characteristics of a probe and its interconnecting elements andprovides methods for their measurement and verification.The evaluation of these characteristics permits a well-defined description and comparability of an eddy currentequipment.By careful choice of the characteristics, a consistent and effective eddy current examination system can bedesigned for a specific application.Where accessories are used, these should be characterised using the principles of this standard.This standard does not give the extent of verification nor acceptance criteria for the characteristics. These aregiven in the application documents.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 1330-5:1998Non-destructive testing - Terminology - Part 5: Terms used in Eddy current testing.3 Terms and definitionsFor the purposes of this European Standard, the terms and definitions given in EN 1330-5:1998 apply.4 Probe and interconnecting elements characteristics4.1 General characteristics4.1.1 ApplicationProbes and interconnecting elements are selected to satisfy the requirements of the intended application.The design is influenced by the instrument with which they are used.4.1.2 Probe typesThe probe is described by:¾ type of material to be examined i.e. ferromagnetic, non-ferromagnetic with high or low conductivity;¾ function e.g. separate or combined transmit receive probe;¾ family e.g. coaxial probe, surface probe;SIST EN 13860-2:2004
EN 13860-2:2003 (E)5¾ measurement mode e.g. absolute, differential;¾ purpose of the examination e.g. detection of discontinuities, sorting or thickness measurement etc.;¾ specific features e.g. focused, shielded, etc.4.1.3 Interconnecting elementsThey may include:¾ cables and/or extensions;¾ connectors;¾ slip rings;¾ rotating heads;¾ transformers;¾ active devices, e.g. multiplexer, amplifier, .4.1.4 Physical characteristicsThe following are to be stated among others:¾ external size and shape;¾ weight;¾ information about mechanical mounting;¾ model number and serial number;¾ material of manufacture of probe housing;¾ composition and thickness of facing material;¾ presence and purpose of core or shield;¾ type of interconnecting elements (see 4.1.3);¾ orientation mark (direction for maximum sensitivity, see 6.2.3.3);¾ position mark (electrical centre, see 6.2.3.4).4.1.5 SafetyThe probe and its interconnecting elements shall meet the applicable safety regulations regarding electrical hazard,surface temperature, or explosion.Normal use of the probe should not create a hazard.SIST EN 13860-2:2004
EN 13860-2:2003 (E)64.1.6 Environmental conditionsThe temperature and humidity for normal use, storage and transport should be specified for the probe and itsinterconnecting elements.The tolerance of the probe and its interconnecting elements to the effects of interference noise and electromagneticradiation shall conform to electromagnetic compatibility (EMC) regulations.Materials used in the manufacture of the probe should be resistant to contaminants.4.2 Electrical characteristicsThe external electrical connections to the probe shall be clearly identified or declared in writing.The electrical characteristics of a probe connected to a specified length and type of cable are:¾ recommended range of excitation current and voltage for safe operation;¾ recommended range of excitation frequencies;¾ impedance of the excitation element in air;¾ resonant frequency of excitation element in air;¾ impedance of the receiving element(s) in air.The electrical characteristics of an extension cable shall also be clearly identified.4.3 Functional characteristicsThe functional characteristics of a probe shall be determined for a defined system.The measurement of the functional characteristics of a probe requires the use of calibration blocks. The materialused for the reference block is determined by the application.The functional characteristics of a probe are:¾ directionality;¾ response to elementary discontinuities (hole, slot);¾ length and width of coverage;¾ area of coverage;¾ minimum dimensions of discontinuities for constant response;¾ penetration characteristics;¾ geometric effects;¾ normalised impedance locus (when frequency is varied) of the exciting element with minimum probe clearancefrom a homogeneous block of a specified material.These characteristics cannot be used alone to establish the performance (e.g. resolution, smallest detectablediscontinuity…) of the probe in a given test system, for a given application.SIST EN 13860-2:2004
EN 13860-2:2003 (E)7When relevant, the influence of interconnecting elements on the functional characteristics of the probe shall bemeasured.5 Verification5.1 GeneralFor a consistent and effective eddy current examination it is necessary to verify that the performance of thecomponent parts of the eddy current test system is maintained within acceptable limits.The physical condition of the reference blocks shall be verified to be within acceptable limits before being used toverify the system, or probes.The measuring equipment used for verification shall be in a known state of calibration.For a better understanding, the verification procedure is identically described in all three parts of EN 13860.5.2 Levels of verificationThere are three levels of verification. Each level defines the time intervals between verification and the complexityof the verification.It is understood that initial type testing has already been done by the manufacturer or under his control.LEVEL 1 - Global functional checkA verification performed at regular intervals of time on the eddy current test system using reference blocks to verifythat the performance is within specified limits.The verification is usually performed at the examination location.The time interval and the reference blocks are defined in the verification procedure.LEVEL 2 - Detailed functional checkA verification on an extended time scale, performed to ensure the stability of selected characteristics of the eddycurrent instrument, probe, accessories, and reference blocks.LEVEL 3 - CharacterisationA verification performed on the eddy current instrument, probe accessories, and reference blocks to ensureconformity with the characteristics supplied by the manufacturer.The organisation requiring the verification shall specify the characteristics to be verified.The main features of verification are shown in Table 1.SIST EN 13860-2:2004
EN 13860-2:2003 (E)8Table 1 — Verification levelsLEVELOBJECTTYPICAL TIMEPERIODINSTRUMENTSRESPONSIBLEENTITY1Global functioncheckStability of systemperformance.Frequently.e.g hourly, dailyReference blocks.USER2Detailed functionalcheck andcalibrationStability of selectedcharacteristics of theinstrument, probesand accessories.Less frequently butat least annually andafter repair.Calibratedmeasuringinstruments,reference blocks.USER3CharacterisationAll characteristics ofthe instrument,probes andaccessories.Once(on release)and when required.Calibrated laboratorymeasuringinstruments andreference blocks.MANUFACTURER,USER5.3 Verification procedureThe characteristics to be verified are dependent on the application. The essential characteristics and the level ofverification shall be specified in a verification procedure.The examination procedure for the application shall refer to the verification procedure. This can restrict the numberof characteristics of a general purpose instrument to be verified for a defined application.Sufficient data on the characteristics featured in an instrument, probe, and reference block, shall be provided inorder that verification may be performed within the scope of this standard.5.4 Corrective actionsLEVEL 1 - When the performance is not within the specified limits, then a decision shall be made concerning theproduct examined since the previous successful verification. Corrective actions shall be made to bring theperformance within acceptable limits.LEVEL 2 - When the deviation of the characteristic is greater than the acceptable limits specified by themanufacturer or in the application document, then a decision shall be made concerning the instrument, the probeor the accessory being verified.LEVEL 3 - When the characteristic is out of the acceptable range specified by the manufacturer or by theapplication document, then a decision shall be made concerning the instrument, the probe or the accessory beingverified.6 Measurement of electrical and functional characteristics of a probe6.1 Electrical characteristics6.1.1 GeneralThe electrical characteristics alone do not define the probe characteristics in its application.SIST EN 13860-2:2004
EN 13860-2:2003 (E)9The methods and measuring instruments given below are for guidance; other equivalent methods andinstrumentation can be used.6.1.2 Measurement conditionsThe measurements are made at the probe connector without the use of interconnecting elements of the inspectionsystem. The probe is placed in air and away from any conductive or magnetic material.The measurements are made for each element of the probe accessible at the probe connector. The other elementsare left open circuit.When the probe is designed for use under particular conditions e.g. temperature or pressure, then any additionalmeasurements that are required shall be specified in the application document.6.1.3 Resonant frequency of the excitation element6.1.3.1 Excitation element with a single coilUsing an impedance meter, measure the resonant frequency Fres of the exciting element.6.1.3.2 Excitation elements with multiple coilsAn excitation element containing multiple coils will give multiple resonance frequencies. The lowest frequency shallbe reported/measured.6.1.4 Impedance of the excitation elementMeasure the resistance R0 using a multimeter, the inductance L0 using an impedance meter. The inductance ismeasured at the lowest frequency of the recommended operating range for the probe.The capacitance C0 is calculated:02res2041LFCp=The model of the excitation element impedance is given in Figure 1.Figure 1 — Excitation element impedance6.1.5 Impedance of the receiving element(s)Measure the resistance using a multimeter, the inductance, and the capacitance using an impedance meter. Themeasured values of impedance can be given as a curve against frequency.SIST EN 13860-2:2004
EN 13860-2:2003 (E)106.2 Functional characteristics6.2.1 GeneralThis standard characterises commonly used probe types. Probes which are designed for special (unusual)applications shall be characterised in accordance with an application document which follows the methodology ofthis standard. The characteristics described in this standard can give useful information about such probes.The functional characteristics are defined for two classes of probes: surface probes and co-axial probes.6.2.2 Measurement conditions6.2.2.1 GeneralA general purpose eddy current instrument characterised in accordance with Part 1 of EN 13860 can be used,provided that it has the required accuracy.Alternatively sufficient instrumentation comprising a voltage/current generator, synchronous detection amplifier anda voltmeter or oscilloscope can be used.When the probe does not feature a connecting cable, then the characteristics of the cable used for themeasurements shall be documented.The probe characteristics are measured within the frequency range specified by the probe manufacturer usingreference blocks containing known features such as slots and holes.The reference blocks shall be made from the material, metallurgical properties and surface finish specified in theapplication document. Its geometry shall comply with the requirements included in the following subclauses. Blocksmade with ferromagnetic material shall be demagnetized before use. The reference block can be replaced by anyother device the equivalence of which shall be demonstrated for the measured characteristic, (alternative blocks,electric circuit, coil, ball, etc.).The functional characteristics can be affected by the presence of any perturbing electromagnetic field orferromagnetic material in the zone of influence of the probe. Care shall be taken to avoid these effects whenmaking the measurements described below.The measurement conditions for each characteristic shall be recorded e.g. excitation frequency andvoltage/current, details of the reference block, etc.The measured values are the amplitude of the signal and, when applicable, the phase of the signal.6.2.2.2 Measurement of the amplitude of the signala) absolute measurementsThe amplitude of the signal is the length of the vector joining the balance point to the point corresponding to themaximum excursion of the signal from the balance point, unless otherwise specified in an application document,see Figure 2a.SIST EN 13860-2:2004
EN 13860-2:2003 (E)11Figure 2a — Amplitude measurement for an absolute signalb) differential measurementsThe amplitude of the signal is the length of the line joining the two extreme points of the signature i.e. peak topeak value, unless otherwise specified in an application document, see Figure 2bFigure 2b — Amplitude measurement for a differential signalc) other measurementsThe method shall be specified in an application document.6.2.2.3 Measurement of the phase angle of the signalThe reference for the measurement of phase angle shall be the positive X axis.The span shall be 360 °, either as 0° to 360° or 0° to ± 180°.The polarity of measurement shall be specified as follows:¾ P360: 0° to 360°, positive is counterclockwise (mathematical convention);¾ N360: 0° to 360°, positive is clockwise;¾ P180: 0 to ± 180°, positive is counterclockwise;¾ N180: 0 to ± 180°, positive is clockwise.The phase angle is the angle between the reference line and the line representing the signal amplitude determinedin 6.2.2.2.SIST EN 13860-2:2004
EN 13860-2:2003 (E)126.2.3 Surface probesUnless otherwise specified, the measurements shall be conducted with constant probe clearance, which will bespecified in the application document.6.2.3.1 Reference blocksReference blocks (A1 to A5) are described in general terms in Figure 3 below.The detailed requirements of each block shall be given in a procedure.For each of these reference blocks, the length and width shall be at least 10 times the length of coverage of theprobe as defined in the probe specifications. When this feature is not known, it shall be replaced by the largest(active) dimension of the probe in the scanning plane. A verification can be made after having measured the lengthof coverage as described in 6.2.3.8.The thickness of the reference block shall be at least twice the standard depth of penetration for the lowestfrequency nominated in the probe specification.Block A1It contains a slot in its centre.As a minimum¾ the slot shall be longer than the "minimum slot length for constant probe response" determined according tothe methodology described in 6.2.3.10;¾ the slot shall be deeper than the "minimum depth of surface-breaking slot for constant probe response"determined according to the methodology described in 6.2.3.11.¾ the slot width shall be defined in the application document.Block A2It contains a hole in its centre.The diameter of the hole is defined in the application document. It is recommended that the depth of the hole bethe same as that of the slot in block A1.Blocks A3Same as block A1, without slot, and with varying thicknesses up to three times the standard depth of penetration,or twice the active dimension of the probe.Block A4Same as block A1, with n parallel slots.¾ all the slots have the same length and width as the slot of block A1;¾ slot depth is increasing from slot 1 to n by a constant step specified in the application document;¾ the spacing between two consecutive slots shall be at least 5 times the length of coverage (6.2.3.8);¾ the distance from the first and the last slot to the adjacent edge shall be at least 2,5 times the edge effectlength.SIST EN 13860-2:2004
EN 13860-2:2003 (E)13The number of slots and their depths are defined in the application document.Block A5Same as block A1, with n parallel slots.¾ all the slots have the same depth and width as the slot of block A1;¾ slot length is increasing from slot 1 to n by a constant step specified in the application document. The ends ofthe longest slot shall be further than 2,5 times the edge effect length away from the edge;¾ the spacing between two consecutive slots shall be at least 5 times the length of coverage (6.2.3.8);¾ the distance from the first and the last slot to the adjacent edge shall be at least 2,5 times the edge effectlength;¾ all the slots are centred with respect to the block;¾ the number of slots and their lengths are defined in the application document.Figure 3 — Reference blocks for surface probesBlock A6A block is defined to obtain a transfer signal. See 6.2.3.16SIST EN 13860-2:2004
EN 13860-2:2003 (E)146.2.3.2 Reference signalReference block: block A1 shall be used for this measurement.Probe motion:Balance the probe on the block with the probe mid way between the slot and the adjacent edge of the block.Verify that no significant change occurs when moving the probe in the vicinity of this position, in the direction of theslot and that of the edge.A linear scan is performed over the middle of the slot with the preferred orientation of the probe perpendicular tothe slot (see Figure 4 below). For this measurement, the preferred orientation shall be the one defined by themanufacturer. In the case where the probe is explicitly designed for scanning slots non-perpendicular to the probemotion (e.g. parallel), an alternative procedure shall be described in the application document.Results:The instrument is adjusted so that the maximum signal corresponds to a given value of the instrument dynamicrange (e.g. 25 %). It shall be verified that no signal saturation occurs in the subsequent measurements.The reference signal Sref is the maximum value of the signal during the scan.The phase of the reference signal is taken as the origin of phases for subsequent measurements.In the following subclauses, all results shall be expressed relatively to Sref.Figure 4 — Probe motion to obtain the reference signal6.2.3.3 Angular sensitivityReference block: block A1 shall be used for this measurement.Probe motion:Scan the central portion of the slot for a range of angles of the probe preferred orientation indicated by themanufacturer with the scanning direction (a goes from 0° to 180°), in steps giving adequate resolution but notexceeding 20°, (see Figure 5). The values of a are specified in the application document.For some probes, scanning the slot in its middle does not correspond to their optimal use. In this case, analternative procedure shall be provided in the application document.SIST EN 13860-2:2004
EN 13860-2:2003 (E)15Figure 5 — Probe motion to measure angular sensitivityResults:The maximum value Smax(a) of the signal for each scan is recorded. Smax(a)/Sref is plotted against a.The orientation for which the maximum value max (Smax)/Sref of Smax(a)/Sref is obtained defines the actual preferredorientation of the probe, which shall be used for the following measurements.Where the actual preferred orientation of the probe differs significantly from the preferred orientation indicated bythe manufacturer, this situation shall be documented; a new orientation mark could be made; the correspondingvalue of Sref shall be used in all subsequent measurements.The case where there are several distinct maxima of Smax/Sref indicates that the probe has several preferredorientations. Therefore, it is desirable to measure the probe characteristics for each preferred orientation.Additional parameters can be defined through such measurement. For instance, a probe anisotropy factor may becalculated:k =
[max(Smax) – min(Smax)]/ max(Smax)where min(Smax) is the minimum of Smax(a).6.2.3.4 Position markThe position mark is different from the orientation mark. This mark placed on the body of the probe shallunambiguously define the position of the electrical centre, according to the measurement method given below.When this mark cannot be properly made on the probe, it shall be defined by means of a sketch, or the distance ofthe mark from a fixed point of the probe can be recorded.Reference block: block A1 shall be used for this measurement.Probe motion:A linear scan is performed over the middle of the slot with the preferred orientation of the probe perpendicular tothe slot.Results:Where there is one peak signal, the probe position mark is one point of the probe housing over the slot where thesignal is a maximum, e.g. absolute signal.SIST EN 13860-2:2004
EN 13860-2:2003 (E)16Where there are two maxima, the probe position mark is one point of the probe housing over the slot where thesignal is zero between the two peaks, e.g. differential signal.6.2.3.5 Edge effectReference block: block A1 shall be used for this measurementProbe motion:With the probe mid-way between the slot and the adjacent edge of the block, the probe is moved from the formerbalance position on a scanning line to the closest edge of the reference block:1) along its preferred orientation;2) perpendicular to its preferred orientation.Results:1)The edge effect is characterised by the distance from the probe position mark to the edge of the block atwhich the signal S is such that:S / Sref = A(A is a value mentioned in the application document);2)The edge effect is characterised by the distance from the secondary probe position mark to the edge ofthe block at which the signal S is such that:S / Sref = A(A is a value mentioned in the application document).6.2.3.6 Response to a holeReference block: block A2 (Figure 3) shall be used for this measurement.Probe motion:The block is scanned in a series of pa
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