1、Designation: E309 11E309 16Standard Practice forEddy-Current Eddy Current Examination of Steel TubularProducts Using Magnetic Saturation1This standard is issued under the fixed designation E309; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This pr
3、actice2 covers a procedure for applying the eddy-current eddy current method to detect discontinuities inferromagnetic pipe and tubing (Note 1) where the article being examined is rendered substantially non-magnetic by the applicationof a concentrated, strong magnetic field in the region adjacent to
4、 the examining coil.NOTE 1For convenience, the term tube or tubular product will hereafter be used to refer to both pipe and tubing.1.2 The procedure is specifically applicable to eddy-current eddy current testing methods using an encircling-coil assembly.However, eddy-current eddy current technique
5、s that employ either fixed or rotating probe-coil assemblies may be used to eitherenhance discontinuity sensitivity on the large diameter tubular products or to maximize the response received from a particular typeof discontinuity.1.3 This practice is intended for use on tubular products having outs
6、ide diameters from approximately 14 to 10 in. (6.35 to 254.0mm). These techniques have been used for smaller and larger sizes however, and may be specified upon contractual agreementbetween the purchaser and the supplier.1.4 This practice does not establish acceptance criteria; they must be specifie
7、d by the using party or parties.1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information only and are not considered standard.1.6 This standard does not purport to address all o
8、f the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E543 Specification for Ag
9、encies Performing Nondestructive TestingE1316 Terminology for Nondestructive Examinations2.2 Other Documents:SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing4ANSI/ASNT CP-189 ASNT Standard for Qualification and Certification of Nondestructive Tes
10、ting Personnel4NAS-410 NAS Certification and Qualification of Nondestructive Test Personnel5ISO 9712 Nondestructive TestingQualification and Certification of Nondestructive Testing Personnel61 This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct r
11、esponsibility of Subcommittee E07.07 on ElectromagneticMethod.Current edition approved Feb. 15, 2011June 1, 2016. Published March 2011June 2016. Originally approved in 1966. Last previous edition approved in 20062011 asE309 - 95E309 - 11.(2006). DOI: 10.1520/E0309-11.10.1520/E0309-16.2 For ASME Boil
12、er and Pressure Vessel Code applications see related Recommended Practice SE 309 in Section V of that Code.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standa
13、rds Document Summary page on the ASTM website.4 Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.5 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Phil
14、adelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.Aerospace Industries Association (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209, http:/www.aia-aerospace.org.6 Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8,
15、CP 401, 1214 Vernier, Geneva,Switzerland, http:/www.iso.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all chan
16、ges accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Bar
17、r Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12.3 Military Standard:MIL-STD-410E Nondestructive Testing Personnel Qualification and Certification53. Terminology3.1 GeneralFor definitions of terms used in this practice, refer to Terminology E1316.4. Summary of Practice4
18、.1 The examination is conducted using one of two general techniques shown in Fig. 1.4.1.1 One technique employs one or more exciter and sensor coils that encircle the tube and through which the tubular productto be examined is passed. Some circuit configurations employ one or more coils that concurr
19、ently function as both exciters andsensors. Alternating current passes through the exciting coil which, by reason of its proximity, induces corresponding currents(eddy currents) to flow in the tubular product. The sensor coil detects the resultant electromagnetic flux related to these currents.The p
20、resence of discontinuities in the tubular product will alter the normal flow of currents and this change is detected by thesensor. The encircling-coil technique is capable of examining the entire circumference of a tubular product.4.1.2 Another technique employs a probe coil with one or more sensors
21、 that are in close proximity to the surface of the tubularproduct to be examined. Since the probe is generally small and does not encircle the article being examined, it examines only alimited area in the vicinity of the probe. This technique is frequently used for examination of welded tubular prod
22、ucts in whichonly the weld is examined by scanning along the weld zone.4.1.3 The magnetic permeability of ferromagnetic materials severely limits the depth of penetration of induced eddy currents.Furthermore, the permeability variations inherent in ferromagnetic tubular products often cause anomalou
23、s test results. A usefulsolution to this problem involves the application of a strong external magnetic field in the region of the examining coil or probe.(a) Encircling Coil.(b) Probe Coillongitudinal scanning of weld seam only.(c) Probe Coilscanning along a spiral path.FIG. 1 Encircling-Coil and P
24、robe-Coil Techniques for Electromagnetic Testing of Tubular ProductsE309 162This technique, known as magnetic saturation, is applied to a magnetic material, such as a steel tube, to suppress the magneticcharacteristics of permeability, hysteresis, etc., so that the material under examination is effe
25、ctively rendered nonmagnetic. Whenachieved, this condition allows an eddy-current eddy current system to measure and detect electrical resistivity and geometricalvariations (including defects) independent of concurrent variations in magnetic properties.4.1.4 Changes in electromagnetic response cause
26、d by the presence of discontinuities are detected by the sensor, amplified, andmodified in order to actuate audio or visual indicating devices, or both, a mechanical marker, or a signal-recording device, or acombination of these. Signals can be caused by outer surface, inner surface, or subsurface d
27、iscontinuities if the eddy-current eddycurrent frequency provides sufficient depth of penetration (see 5.4). The eddy-current eddy current method is sensitive tometallurgical variations that occur as a result of processing, thus all received indications are not necessarily indicative of defectivetub
28、ing.5. Significance and Use5.1 The purpose of this practice is to outline a procedure for the detection and location of discontinuities such as pits, voids,inclusions, cracks, or abrupt dimensional variations in ferromagnetic tubing using the electromagnetic (eddy-current) (eddycurrent) method. Furt
29、hermore, the relative severity of a discontinuity may be indicated, and a rejection level may be set withrespect to the magnitude of the indication.5.2 The response from natural discontinuities can be significantly different than that from artificial discontinuities such as drilledholes or notches.
30、For this reason, sufficient work should be done to establish the sensitivity level and set-up required to detectnatural discontinuities of consequence to the end use of the product.5.3 Eddy-current Eddy current testing systems are generally not sensitive to discontinuities adjacent to the ends of th
31、e tube. Theextent of the end effect region can be determined in accordance with 8.6.5.4 Since the density of eddy currents decreases nearly exponentially as the distance from the external surface increases, theresponse to deep-seated discontinuities decreases and some deep-seated discontinuities may
32、 give no detectable repsonse.5.5 Discontinuity orientation also affects the system response and should be taken into consideration when establishing theexamination sensitivity.5.6 In preparing a reference standard for welded tubing, artificial discontinuities should be placed in both the weld metal
33、andthe parent metal when the responses are expected to be different and if both are to be examined. The apparatus is then adjustedto obtain an optimum signal-to-noise ratio.5.6.1 When examining only the weld area, the discontinuities shall be placed only in the weld area.5.7 The examination frequenc
34、y and the type of apparatus being used should be considered when choosing the examining speed.Certain types of equipment are effective only over a given speed range; therefore, the examining speed should fall within this range.5.8 Discontinuities such as scratches or seams that are continuous and un
35、iform over the full length of the tube may not alwaysbe detected with differential encircling coils or probes scanned along the tube length.6. Basis of Application6.1 The following acceptance criteria may be specified in the purchase specification, contractual agreement, or elsewhere, andmay require
36、 agreement between the purchaser and the supplier:6.1.1 Time of examination or point(s) in the manufacturing process at which the material will be examined,6.1.2 Maximum time interval between equipment calibration checks,6.1.3 Methods for determining the extent of end effect,6.1.4 Size and type of p
37、roduct,6.1.5 Type, method of manufacture, dimensions, location, and number of artificial discontinuities to be placed on the referencestandard,6.1.6 Methods of verifying dimensions and allowable tolerances of artificial discontinuities,6.1.7 Extent of examination, and6.1.8 Disposition of material wi
38、th indications.6.1.9 Operator Qualification and Certification If required, NDT personnel specified in the contractual agreement, personnelperforming examinations to this standard shall be qualified in accordance with a nationally or internationally recognized NDTpersonnel qualification practice or s
39、tandard such as ANSI/ASNT-CP-189, SNT-TC-1A, MIL-STD-410, NAS-410, ISO 9712, or asimilar document. document and certified by the employer or certifying agency, as apllicable. The practice or standard used andits applicable revision shall be documentedidentified in the contractual agreement between t
40、he using parties.NOTE 2MIL-STD-410 is canceled and has been replaced with NAS-410; however, it may be used with agreement between contracting parties.6.1.10 Qualification of Nondestructive AgenciesIf specified in the contractual agreement, NDT agencies shall be qualified andevaluated in accordance w
41、ith Practice E543. The applicable edition of Practice E543 shall be specified in the contractualagreement.E309 1637. Apparatus7.1 Electronic ApparatusThe electronic apparatus shall be capable of energizing the coils or probes with alternating currentsof a selected frequency and shall be capable of s
42、ensing the changes in the electromagnetic response of the sensors. Equipment mayinclude appropriate signal processing circuits such as a phase discriminator, filter circuits, etc., as required for the particularapplication.7.2 Encircling-Coil AssemblyThe encircling-coil assembly shall consist of one
43、 or more electrical coils that encircle the articlebeing examined.7.3 Probe-Coil AssemblyThe probe-coil assembly normally contains an exciting coil and a sensor, although in some cases theexciter and sensor are one and the same.7.4 Magnetic Saturation SystemThe magnetic saturation system shall consi
44、st of a suitable method of applying a strongmagnetic field to the region of the tube adjacent to the coil or probe-coil assembly so as to render that region of the tube effectivelynonmagnetic. Typical systems employ either permanent magnets or electromagnets.7.5 Driving MechanismThe movement of the
45、tube through the coil or past the probe shall be performed at uniform speed andwith minimum vibration of the tube, coil, and probe.7.6 Reference StandardThe standard used to adjust the sensitivity of the apparatus shall be free of interfering discontinuitiesand shall be of the same nominal alloy, te
46、mper, and dimensions as the tubes to be examined on a production basis. It shall be ofsufficient length to permit the spacing of artificial discontinuities to provide good signal resolution and be mechanically stablewhile in the examining position in the apparatus. Artificial discontinuities placed
47、in the tube shall be one or more of the followingtypes. (See Fig. 2.)7.6.1 NotchesNotches may be produced by Electric Discharge Machining (EDM), milling, or other means. Longitudinal,transverse, or both may be used (Note 32). Orientation, dimensions (width, length, and depth), and configuration of t
48、he notchesaffect the response of the eddy-current eddy current system. Notch depth is usually specified as a percentage of nominal wallthickness of the tubular product being examined. Notches may be placed on the outer, inner, or both surfaces of the referencestandard. Outer surface notches provide
49、an indication of system response to discontinuities originating on the outer tube surface;whereas inner surface notches provide an indication of system response to discontinuities originating on the inner tube surface.NOTE 2Longitudinal notch standards are normally used when testing with a rotating-probe system.7.6.2 HolesDrilled holes may be used. They are usually drilled completely through the wall. Care should be taken duringdrilling to avoid distortion of the tube and hole.7.6.3 The configuration, orientation, and dimensions (diameter of holes and the wid
