1、Designation: B 548 03Standard Test Method forUltrasonic Inspection of Aluminum-Alloy Plate for PressureVessels1This standard is issued under the fixed designation B 548; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers pulse-echo ultrasonic inspectionof aluminum-alloy plate of thickness equal to or greater than0
3、.500 in. (12.7 mm) for use in the fabrication of pressurevessels. The ultrasonic test is employed to detect gross internaldiscontinuities oriented in a direction parallel to the rolledsurface such as cracks, ruptures, and laminations, and toprovide assurance that only plate that is free from rejecta
4、blediscontinuities is accepted for delivery.1.2 The inspection method and acceptance criteria includedin this standard shall be limited to plate of the followingaluminum alloys: 1060, 1100, 3003, Alclad 3003, 3004, Alclad3004, 5050, 5052, 5083, 5086, 5154, 5254, 5454, 5456, 5652,6061, and Alclad 606
5、1.1.3 This test method applies only to ultrasonic tests usingpulsed longitudinal waves which are transmitted and receivedby a search unit containing either a single crystal or acombination of electrically interconnected multiple crystals.Ultrasonic tests employing either the through-transmission ort
6、he angle-beam techniques are not included.1.4 This test method shall be used when ultrasonic inspec-tion as prescribed herein is required by the contract, purchaseorder, or referenced plate specification.1.5 The values stated in inch-pound units are to be regardedas the standard. The values given in
7、 parentheses are forinformation only.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 lim
8、itations prior to use.2. Referenced Documents2.1 The following documents of the issue in effect on dateof material purchase form a part of this specification to theextent referenced herein:2.2 ASTM Standards:2E 114 Practice for Ultrasonic Pulse-Echo Straight-BeamExamination by the Contact MethodE 21
9、4 Practice for Immersed Ultrasonic Examination by theReflection Method Using Pulsed Longitudinal WavesE 317 Practice for Evaluating Performance Characteristicsof Ultrasonic Pulse-Echo Testing Systems Without the Useof Electronic Measurement Instruments2.3 Other Standards:ASNT Recommended Practice fo
10、r Nondestructive TestingPersonnel Qualification and CertificationUltrasonicTesting MethodSNT-TC-1A33. Summary of Method3.1 The plate is inspected ultrasonically by scanning onerolled surface with a beam of pulsed longitudinal waves whichis oriented in a direction perpendicular to the entry surface o
11、fthe plate. The ultrasound is transmitted into the plate either bythe direct contact, immersion, or liquid-column couplingmethod. During the scan, an indication representing the firstback reflection is observed on the A-scan screen of the testinstrument.3.2 When the test system sensitivity level is
12、appropriatelyadjusted, a discontinuity is detected during the scan by notingan isolated indication associated with a loss of the first backreflection indication. The apparent size of the discontinuity isdetermined by measuring the total area in the scanned entrysurface of the plate where the isolate
13、d indication and the lossof back reflection persist. The estimated discontinuity size andlocation are then compared with suitable acceptance criteria.NOTE 1Additional information describing ultrasonic tests by thedirect contact method and by the immersion method is available inPractices E 114 and E
14、214.1This test method is under the jurisdiction of ASTM Committee B07 on LightMetals and Alloys and is under the jurisdiction of Subcommittee B07.03 onAluminum Alloy Wrought Products.Current edition approved Nov. 1, 2003. Published November 2003. Originallyapproved in 1971. Last previous edition app
15、roved in 1997 as B 548 90 (1997).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 The American
16、 Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4. Significance and Use4.1 A number of factors such as the condition of the entrya
17、nd back surfaces of the plate, the inclination of the ultrasonicbeam with respect to the entry surface, and the performancecharacteristics of the test system may cause either a reductionof isolated indications or a substantial loss of back reflectionand thereby could seriously impair the reliability
18、 of the testprocedure outlined in this standard.4.2 Accurate evaluations of discontinuity size also may belimited significantly by variations in beam characteristicswhich exist in most search units. For this reason, discontinuitysize as determined by the test procedure outlined in this methodis rega
19、rded as “apparent” or “estimated” in recognition of thelimited quantitative value of the measurement.4.3 Because a large number of interacting variables in a testsystem can adversely influence the results of an ultrasonic test,the actual quantitative effects of detected discontinuities uponthe mecha
20、nical properties of the inspected plate are difficult toestablish. Consequently, this ultrasonic inspection method isnot applicable as an exclusive indicator of the ultimate qualityand performance of pressure vessels but provides a reliablecontrol of plate quality to avoid failure during the forming
21、process for fabrication of vessels.5. Apparatus5.1 Test InstrumentAny electronic device that producespulsed longitudinal waves and displays ultrasonic reflectionson an A-scan indicator when used with an appropriate searchunit is satisfactory. The instrument shall provide stable, linearamplification
22、of received pulses at a selected test frequency andshall be free from significant interface signal interference at therequired sensitivity level.5.2 Search UnitThe search unit recommended for thisstandard is the flat nonfocusing type, and contains a piezoelec-tric crystal which generates and receive
23、s longitudinal waves atthe rated frequency when connected to the test instrumentthrough a suitable coaxial cable. A dual-crystal search unitcontaining both a transmitting and a receiving crystal in onecontainer may be used provided the test instrument willaccommodate two-crystal operation and the re
24、sulting pulse-echo test is equivalent to that obtained with a search unitcontaining a single-crystal.5.2.1 The total effective area of the crystal or combinationof crystals in the search unit used for initial scanning shall notbe less than 0.4 in.2(2.6 cm2) nor greater than 3.0 in.2(19.4cm2).5.2.2 T
25、he effective diameter of the round search unit used toevaluate discontinuity size shall not exceed 0.75 in. (19 mm).NOTE 2For control purposes, the performance characteristics of thetest instrument and search unit may be established in accordance withprocedures outlined in Practice E 317.5.3 TankFor
26、 tests by the immersion method, any con-tainer is satisfactory that will facilitate the accurate, stablepositioning of both the search unit and the plate to beinspected.5.4 Scanning ApparatusDuring the inspection procedure,the search unit is supported by any one of the followingdevices. The scanning
27、 apparatus shall permit measurement ofboth the scan distance and the index distance within 60.1 in.(62 mm).5.4.1 Manipulator and BridgeWhen a manipulator isused in tests by the immersion method, the manipulator shalladequately support a search tube containing a search unit andshall provide fine adju
28、stment of angle within 1 in two verticalplanes that are perpendicular to each other. The bridge shall beof sufficient strength to provide rigid support for the manipu-lator and shall allow smooth, accurate positioning of the searchunit. Special search unit supporting fixtures may be usedprovided the
29、y meet the requirements prescribed for a manipu-lator and bridge.5.4.2 Liquid Coupling NozzleFor tests by the liquid-column coupling method, the nozzle is usually positionedmanually and shall be capable of containing the couplant whilerigidly supporting the search unit with its active surfaceimmerse
30、d in the couplant. The couplant distance shall bemaintained so that the second couplant reflection is to the rightof the first back reflection on the instrument cathode ray tube(CRT). The couplant path shall not vary more than 614 in. (6.4mm) during calibration, initial scanning, and discontinuityev
31、aluation. The recommended minimum inside dimension ofthe nozzle is 1.0 in. (25 mm) greater than the maximumdimension of the crystal surface in the search unit. Provisionsalso should be included for adjustment of search unit inclina-tion within 1 in two vertical planes that are perpendicular toeach o
32、ther.NOTE 3Nozzles containing either sealed or unsealed openings may beused for inspecting plate provided the test results obtained with eitherdevice are equivalent to those obtained by the immersion method.5.4.3 Contact Scanning UnitDuring tests by the contactmethod, the search unit usually is supp
33、orted and positionedmanually on the entry surface of the inspected plate. However,special fixtures for contact scanning may be employed pro-vided their use ensures conformance to the requirements in thisspecification.5.5 CouplantClean, deaerated water at room temperatureis the recommended couplant f
34、or tests either by the immersionmethod or by the liquid-column coupling technique. Inhibitorsor wetting agents or both may be used. For tests by the contactmethod, the recommended couplant is clean, light-grade oil.NOTE 4Other coupling liquids may be employed for inspecting plateprovided their use d
35、oes not adversely affect test results.6. Personnel Requirements6.1 The testing operator performing the ultrasonic examina-tion prescribed in this standard shall be qualified and certifiedto at least a Level IUltrasonic Testing in accordance with theASNT Recommended Practice SNT-TC-1A.6.2 The require
36、d documentation supporting qualificationand certification of ultrasonic testing operators shall be estab-lished by the certifying agency and shall be available uponrequest by the purchaser.7. Condition of Plate7.1 The entry and back surfaces of the inspected plate shallbe sufficiently clean, smooth,
37、 and flat to maintain a first backB548032reflection amplitude greater than 50 % of the initial standard-ization amplitude while scanning an area in the plate that doesnot contain significant isolated ultrasonic discontinuities.7.2 The inspected plate shall be at room temperature duringthe test.8. Pr
38、ocedure8.1 Preferred MethodThe ultrasonic test may be per-formed by either the liquid column coupling, the direct contact,or the immersion methods. However, the immersion method ispreferred.8.1.1 Maintain the couplant distance so that the secondcouplant reflection is to the right of the first back r
39、eflection onthe instruments A-scan display. The couplant path shall notvary more than 614 in. (6.4 mm) during calibration, initialscanning, and discontinuity evaluation.8.2 Test FrequencyWhen using any of the three methodslisted in 8.1, the recommended test frequency is 5.0 MHz.Other test frequencie
40、s between 2.0 MHz and 10.0 MHz may beemployed when necessary to minimize possible adverse effectsof plate thickness, microstructure, and test system characteris-tics upon test results and thereby maintain a clean, easilyinterpreted A-scan screen pattern throughout the inspection.8.3 Sensitivity Stan
41、dardizationStandardize the sensitivitylevel of the test system operating at the selected frequency byadjusting the instrument gain control to obtain a first backreflection amplitude of 75 6 5 % of the vertical limit exhibitedby the A-scan indicator when the search unit is positioned overan area free
42、 from significant discontinuities in the plate to beinspected. During tests by either the immersion method or theliquid column coupling method, adjust the angular alignmentof the search unit to obtain a maximum number of backreflections before the final sensitivity level is established.8.4 ScanningW
43、ith no further adjustments of the instru-ment gain controls, locate the search unit over one corner of theplate to be inspected so that the edge of the crystal in the searchunit is about 1 in. (25 mm) from either edge of the plate.8.4.1 Subsequent to checking the angular alignment of thesearch unit
44、with respect to the rolled entry surface to ensure amaximum first back reflection, proceed to scan the platecontinuously by moving the search unit at a constant scanningrate (see 8.6) from the initial starting position to the oppositeedge in a direction perpendicular to the predominant rollingdirect
45、ion of the plate.8.4.2 During the scan, note the occurrence of isolateddiscontinuity indications and monitor the amplitude of the firstback reflection by continuously observing the A-scan indicatorscreen.NOTE 5Auxiliary monitoring devices may be employed in the testsystem to enhance detection reliab
46、ility during the scan.8.5 Scan IndexWhen the initial scan is completed, movethe search unit over a predetermined scan index distance in adirection parallel to the predominant rolling direction of theplate and proceed with a second scan along a line parallel to theinitial scanning direction while obs
47、erving the test pattern on theA-scan indicator screen. Calculate the scan index distance asfollows:Scan index distance in.!, Si5 0.8 1 0.7 Ds(1)Scan index distance mm!, Si5 20 1 0.7 Ds(2)where:Ds= actual crystal diameter.8.5.1 Continue the inspection by constantly observing thetest pattern on the A-
48、scan indicator while successively scan-ning the plate at a constant scanning rate in a directionperpendicular to the predominant rolling direction of the plateand indexing the search unit through the index distancecalculated in 8.5.8.5.2 During the inspection procedure, check the test systemsensitiv
49、ity standardization periodically by noting the amplitudeof the first back reflection when the search unit is repositionedover the reference area of the plate and by adjusting theinstrument gain control as required to maintain the sensitivitystandardization specified previously in 8.3.8.6 Scanning RateWhen the screen pattern on the A-scanindicator is monitored visually by the test operator during theinspection, the scanning rate shall not be greater than 12 in./s(305 mm/s).NOTE 6Scanning rates greater than 12 in./s (305 mm/s) may beemployed if auxiliary mo
