1、Designation: E1901 18Standard Guide forDetection and Evaluation of Discontinuities by ContactPulse-Echo Straight-Beam Ultrasonic Methods1This standard is issued under the fixed designation E1901; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、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 guide covers procedures for the contact ultrasonicexamination of bulk materials or part
3、s by transmitting pulsedultrasonic waves into the material and observing the indica-tions of reflected waves. This guide covers only examinationsin which one search unit is used as both transmitter andreceiver (pulse-echo). This guide includes general require-ments and procedures that may be used fo
4、r detectingdiscontinuities, locating depth and distance from a point ofreference and for making a relative or approximate evaluationof the size of discontinuities as compared to a referencestandard.1.2 This guide complements Practice E114 by providingmore detailed procedures for the selection and st
5、andardizationof the examination system and for evaluation of the indicationsobtained.1.3 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.
6、1.4 This guide does not purport to address all of the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this guide to establish the appropriate safety,health, and environmental practices and determine the appli-cability of regulatory limitations prior to use.1.5
7、 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Tr
8、ade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2E114 Practice for Ultrasonic Pulse-Echo Straight-BeamContact TestingE127 Practice for Fabrication and Control of AluminumAlloy Ultrasonic Standard Reference BlocksE317 Practice for Evaluating Performance Characteristics ofUltrasonic Puls
9、e-Echo Testing Instruments and Systemswithout the Use of Electronic Measurement InstrumentsE428 Practice for Fabrication and Control of Metal, Otherthan Aluminum, Reference Blocks Used in UltrasonicTestingE543 Specification for Agencies Performing NondestructiveTestingE1158 Guide for Material Select
10、ion and Fabrication ofReference Blocks for the Pulsed Longitudinal Wave Ul-trasonic Testing of Metal and Metal Alloy ProductionMaterialE1316 Terminology for Nondestructive Examinations2.2 ASNT Standard:SNT-TC-1A Recommended Practice for Personnel Qualifi-cation and Certification in Nondestructive Te
11、sting Person-nel32.3 ANSI/ASNT Standard:ANSI/ASNT CP-189 ASNT Standard for Qualification andCertification of Nondestructive Testing Personnel32.4 Aerospace Industries Association Document:NAS-410 NAS Certification and Qualification of Nonde-structive Test Personnel41This guide is under the jurisdict
12、ion of ASTM Committee E07 on Nondestruc-tive Testing and is the direct responsibility of Subcommittee E07.06 on UltrasonicMethod.Current edition approved July 1, 2018. Published July 2018. Originally approvedin 1997. Last previous edition approved in 2013 as E1901 - 13. DOI: 10.1520/E1901-18.2For re
13、ferenced 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.
14、43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4Available from Aerospace Industries Association of America, 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 Intern
15、ational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, G
16、uides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.12.5 ISO Standard5ISO 9712 Non-destructive testing Qualification and cer-tification of NDT personnel3. Terminology3.1 DefinitionsFor definitions of terms used in this guide,see Terminology E1
17、316.4. Basis for Application4.1 Contractual AgreementThe using parties should agreeon the applicable procedural requirements, as listed herein,prior to the examination of any material.4.1.1 Materials, sizes, and shapes examined,4.1.2 Stage of manufacture when examined (time ofexamination),4.1.3 Surf
18、ace finish requirements,4.1.4 Minimum equipment requirements, as in Table 1herein,4.1.5 Search unit size, frequency and type,4.1.6 Couplant,4.1.7 Automated turning, fixturing or scanning, or both, asapplicable,4.1.8 Type of reference block standards including surfacecurvature,4.1.9 Standardization d
19、etails, including attenuation compen-sation and DAC techniques,4.1.10 The surfaces to be examined and the scanning path,4.1.11 Acceptance standards,4.1.12 Personnel certification level, and4.1.13 Instrument characteristics.4.2 Written ProcedureUltrasonic examinations performedin accordance with this
20、 guide should be detailed in a writtenprocedure. Documentation of procedure qualification should bemaintained by the preparer. Procedures should be sufficientlydetailed so that other qualified personnel may duplicate theexamination and obtain equivalent results.4.3 Personnel QualificationsIf specifi
21、ed in the contractualagreement, personnel performing examinations to this standardshall be qualified in accordance with a nationally or interna-tionally recognized NDT personnel qualification practice orstandard such asANSI/ASNT-CP-189, SNT-TC-1A, NAS-410,ISO 9712 or a similar document and certified
22、 by the employeror certifying agency, as applicable. The practice or standardused and its applicable revision should be identified in thecontractual agreement between the using parties.4.4 If specified in the contractual agreement, NDT agenciesshould be qualified and evaluated as described in Practi
23、ceE543.5. Summary of Guide5.1 This guide describes a means for obtaining an evalua-tion of discontinuities in materials by contact examinationusing longitudinal waves. Equipment, reference standards,examination and evaluation procedures, and documentation ofresults are described in detail.6. Signifi
24、cance and Use6.1 This guide provides procedures for the application ofcontact straight-beam examination for the detection and quan-titative evaluation of discontinuities in materials.6.2 Although not all requirements of this guide can beapplied universally to all examinations, situations, andmateria
25、ls, it does provide basis for establishing contractualcriteria between the users, and may be used as a general guidefor preparing detailed specifications for a particular applica-tion.6.3 This guide is directed towards the evaluation of discon-tinuities detectable with the beam normal to the entry s
26、urface.If discontinuities or other orientations are of concern, alternatescanning techniques are required.7. Apparatus7.1 Apparatus should include the following:7.1.1 Electronic EquipmentThe electronic equipmentshould be capable of producing and processing electronicsignals at frequencies in the ran
27、ge of the search unit frequen-cies being used. The equipment and its display should providecharacteristics as listed in Table 1, that are suitable for thespecific application at the specified frequency, as determined inaccordance with the procedures and tolerances described inPractice E317. The equi
28、pment, including the search unit,should be capable of producing echo amplitudes of at least60 % of full screen height from the reference reflector requiredfor the examination, with the material noise level, from front toback surface not exceeding 20 % of full screen height.Alternatively, if these co
29、nditions can be met at one half the partthickness, the part may be inspected from both sides.NOTE 1The using parties should agree on the minimum instrumentcharacteristics prior to conducting an examination.7.1.2 Voltage RegulatorIf fluctuations in line voltagecause indication amplitude variations ex
30、ceeding 612 dB, avoltage regulator should be required on the power source. Thisrequirement is not applicable to battery-operated units.5Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http:/www.iso.org.TABLE 1 Minim
31、um Equipment Requirements (Longitudinal Wave)Instrument CharacteristicsUltrasonic TestFrequency MHZ(Record)Vertical limit, in. (mm) or percentof full screen heightUpper vertical linearity limit in. (mm)or percent of full screen heightLower vertical linearity limit in. (mm)or percent of full screen h
32、eightUltrasonic sensitivity, hole size,64 ths, distance, in (mm)Entry surface resolution, in. (mm)Back surface resolution in. (mm)Horizontal limit, in. (mm) orpercent of full screen widthHorizontal linearity range, in. (mm)or percent of full screen widthE1901 1827.1.3 Search UnitsThe contact search
33、unit selected shouldbe capable of transmitting and receiving ultrasound at therequired frequencies and energy levels necessary for disconti-nuity detection in the material being examined. Only longitu-dinal wave, straight beam, non-focused search units should beused. Dual element search units may pr
34、ovide better near-surface resolution and detection of small discontinuities.Generally, round or rectangular search units are used forexamination whereas round search units with symmetricalsound beam patterns are used for evaluation. Typical searchunit sizes range from18 in. (3.2 mm) in diameter to 1
35、-18 in.(28.6 mm) in diameter with other sizes and shapes available forspecial applications. Search units may be fitted with contouredshoes to enhance coupling with curved surfaces.7.1.4 Alarm(s)For the examination of parts with regularshape and parallel surfaces such as machined cylinders, rounds,ba
36、rs, forgings, etc. an audible/visual alarm may be used inconjunction with visual monitoring of the display for thedetection of discontinuities or for the monitoring and detectionof loss of back surface reflection, or both. The alarm should beadjustable to allow triggering at commonly required indica
37、tionamplitudes, back-echo heights, and depths. During examina-tion the audible visual alarm should be easily detectable by theoperator.7.1.4.1 When reduction in the amplitude of back-surfacereflection is monitored simultaneously with the detection oflower amplitude signals from small, discrete disco
38、ntinuities,two separate gate/alarm systems are required. The negativeslaved alarm system may also provide for a significantly lowerreceiver gain at the gated depth to avoid back-echo saturation.See 10.1 and 10.4.7.1.4.2 For some applications it may be advantageous toutilize a flaw gate system in whi
39、ch the echo-amplitude alarmlevel can be varied as a function of target depth. Refer todistance/amplitude gate (DAG) in 9.3.2.1.7.2 CouplantAcouplant, usually a liquid or semi-liquid, isrequired between the face of the search unit and the examina-tion surface to permit transmittance of ultrasound fro
40、m thesearch unit into the material under examination unless thetransducer is specially designed for “dry” coupling by themanufacturer. Typical couplants include water, cellulose gel,oil and grease. Corrosion inhibitors or wetting agents or bothmay be used. Couplants selected must not be detrimental
41、to theproduct or the process. The same couplant used for standard-ization should be used for the examination. During the perfor-mance of a contact ultrasonic examination, the couplant layerbetween search unit and examination material must be main-tained such that the contact area is held constant wh
42、ilemaintaining adequate couplant thickness. Lack of couplant thatwill reduce the effective contact area, or excess couplant, willreduce the amount of energy transferred between the searchunit and the examination surface. These couplant variations, inturn, result in examination sensitivity variations
43、.7.2.1 The couplant should be selected such that its viscosityis appropriate for the surface finish of the material to beexamined. The examination of rough surfaces generally re-quires a high-viscosity couplant and will result in somedeterioration of near-surface discontinuity detection. The tem-per
44、ature of the material surface can change the couplantsviscosity as in the case of oil and grease. See Table 2 for thesuggested viscosity of oil couplants for given surface rough-nesses.7.2.2 At elevated temperatures as conditions warrant, heat-resistant coupling materials such as silicone oils, gels
45、, orgreases should be used. Further, intermittent contact of thesearch unit with the part surface or auxiliary cooling of thesearch unit may be necessary to avoid temperature changes thataffect the ultrasonic characteristics of the search unit.At highertemperatures, certain couplants based on inorga
46、nic salts orthermoplastic organic materials, high-temperature delay mate-rials (shoes) and search units that are not affected by hightemperatures may be required.7.2.3 Where constant coupling over large areas is required,as in automated examination, or where severe changes insurface roughness are fo
47、und, other methods of coupling such asliquid gap coupling will usually provide a better examination.In this case, the search unit does not contact the examinationsurface, but is separated by a distance of about 0.02 in. (0.5mm) filled with couplant. Liquid flowing through the searchunit mechanism fi
48、lls the gap. The flowing liquid provides thecoupling path and has the additional advantage of cooling thesearch unit if the examination surface is warm.7.2.4 Another means of direct contact coupling is providedby the wheel search unit. The search unit is mounted at thecorrect angle to a stationary a
49、xle about which rotates aliquid-filled flexible tire. A minimum amount of couplantprovides for ultrasonic transmission into the examinationsurface since the elastic tire material is in rolling contact andconforms closely to the surface.7.3 Reference StandardsThe production item itself maybe an adequate standard using the height of the back-wall echofor reference. For more quantitative information, charts such asDistance Gain Size (DGS, also known as AVG in Germantranslation), representing distance-amplitude relationships ofknown reflector sizes for a particular sea
