1、Designation: B 773 96 (Reapproved 2002)e1Standard Guide forUltrasonic C-Scan Bond Evaluation of Brazed or WeldedElectrical Contact Assemblies1This standard is issued under the fixed designation B 773; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEParagraph 1.3 was corrected editorially in June 2002.INTRODUCTIONThis guidance document is th
3、e result of an investigation by the ASTM Committee B04.04 TaskForce on Ultrasonic Bond Testing of Electrical Contacts. Although ultrasonic interrogation is widelyemployed as a non-destructive evaluation method, its application to the testing of electrical contactbonds requires specific techniques.2,
4、3The desire to study the variation of technique and its effect upontest results was responsible for a round-robin test program. The program was conducted in two phasesin an attempt to standardize practices which would improve testing agreement. This study providedanalysis and suggestions for reducin
5、g the variability of test results. The decision of the committee wasto publish a summary of this information to serve as guidelines for writing specifications that willincorporate practices.1. Scope1.1 This guide describes ultrasonic testing procedures thatcan be used for evaluating the bond quality
6、 of electrical contactassemblies manufactured by brazing or welding.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with it
7、s use. It is theresponsibility of the user of this standard to become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet for this product/material as pro-vided by the manufacturer, to establish appropriate safety andhealth practices, and determine the ap
8、plicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 214 Practice for Immersed Ultrasonic Examination by theReflection Method Using Pulsed Longitudinal Waves4E 500 Terminology Relating to Ultrasonic Examination5E 1001 Practice for Detection and Evaluation of
9、Disconti-nuities by the Immersed Pulse-Echo Ultrasonic Methodusing Longitudinal Waves42.2 American Society for Nondestructive Testing Standard(ASNT):SNT-TC-1A Recommended Practice for Personnel Qualifi-cation and Certification in Nondestructive Testing63. Summary of Guide3.1 Pulse-echo TechniqueThe
10、pulse-echo technique isemployed as an ultrasonic testing method which displaysreflected energy pulses. A Piezoelectric transducer (typically1525 M Hz frequency with 0.5- to 1.5-in. (12.7- to 38.1-mm)focal length in water) converts the original electrical pulse intoa mechanical sound wave and then al
11、so acts as a receiver of thereflected mechanical energy, converting it back into usefulelectrical energy. The electrical instrumentation used with thetransducer generates, receives, amplifies, and displays thecontrolled electrical pulses. (See Practices E 214 and E 1001.)3.2 C-ScanThe amplified elec
12、trical signals as receivedfrom the transducer are gated for time/distance and establishthe depth of analysis. When the transducer (coupled through awater medium) is made to traverse in the X-Y directions, the1This guide is under the jurisdiction of ASTM Committee B02 on NonferrousMetals and Alloys a
13、nd is the direct responsibility of Subcommittee B02.11 onElectrical Contact Test Methods.Current edition approved May 10, 1996. Published July 1996. Originallypublished as B 773 87. Last previous edition B 773 87 (1991)e1.2Buckley, R. I., Commey, R. R., Jr., and Popat, P. V.,“Nondestructive Ultrason
14、icInspection of Braze Bonds in High Current Electrical Contact Assemblies,”Proceedings of the Holm Conference on Electrical Contacts, 1971, pp. 6371.3Jost, E., and Fontaine, G., “Ultrasonic In-line Inspection Technique for ContactMaterials,” Proceedings of the Holm Conference on Electrical Contacts,
15、 1979, pp.209213.4Annual Book of ASTM Standards, Vol 03.03.5Discontinued; see 1991 Annual Book of ASTM Standards, Vol 03.036Available from ASNT, 1711 Arlingate Lane, P.O. Box 28518, Columbus, OH43228-0518.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-
16、2959, United States.gated electrical signals are then used to describe a two-dimensional plan view of defects in the interior of the testedobject(s). This plan view of defect information at a given depthof analysis (that is, the brazed or welded layer within thecontact assembly) is called a C-scan.
17、(See Terminology E 500.)3.3 Data Presentation:3.3.1 The gated C-scan signals are used to drive an X-Yplotter/printer that provides a permanent record of the defectplane being examined.3.3.2 The sensitivity of the instrument (alarm levels) isadjusted with the printer circuit by a technician to provid
18、e anaccurate resolution level for the true characterization of de-fects.3.3.3 The calibrated C-scan printed display can then be usedto evaluate the bonded area (or unbonded area shapes) of anarray of contacts under examination.4. Significance and Use4.1 This guide is recommended to be used in prepar
19、ingspecifications for the non-destructive evaluation of brazed orwelded electrical contact bonded area.7The recommendedprocedures are meant to improve the reproducibility of test dataamong various laboratories. Specific differences among equip-ment models and technician skills do exist which will li
20、mitabsolute correlation. This guide provides an indication of thedegree of variability which has been observed as realisticamong industry participants.4.2 Ultrasonic testing alone does not insure an understand-ing of bonded integrity. Other attributes (that is, strength) mayrequire correlation with
21、destructive test methods.5. Procedure5.1 Fabricated StandardsStandards must be producedfrom good previously C-scanned parts from the same processand dimensions as the parts to be examined. Each standardshould contain three flat-bottomed holes: 0.015-, 0.031-, 0.062-in. (0.381-, 0.787-, 1.575-mm) dia
22、meter. The centerline spac-ing of adjacent holes should equal the diameter of the nextlarger hole. Require a flat end mill for finish cut and controldepth from 0.000 to 0.005 in. (0.000 to 0.127 mm) into theactual brazed or welded layer.5.2 System CalibrationThe ultrasonic transducer, electri-cal in
23、strumentation and display printer should be capable ofaccurate reproduction of the standard. Include this standard inevery array of tested parts as an indication of system perfor-mance.5.3 Standard PartsOften it is necessary to obtainmatched, focused transducers to achieve interlaboratory corre-lati
24、on of system resolution on fabricated standard sets. Never-theless, display sensitivity differences can exist which are bestresolved by the use of actual parts as standards. The vendor anduser select an array of parts with various degrees of bondinterface defects and these parts are shared to demons
25、tratereproducibility during each set-up.5.4 Scan Traverse ParallelismThe tank bottom or supportplane for the parts under investigation must be parallel (0.005in. (0.127 mm) maximum deviation) with the plane of the X-Yrails of the scanner. The transducer and CRT display may beused to measure this var
26、iation directly and then accomplishverification by varying the location of standards over the fulltraverse of the C-scan area.5.5 Print QualityIn addition to electrical system calibra-tions, it has been observed that printer performance cansignificantly affect the accuracy of a C-scan display. Direc
27、tparticular care towards stylus parameters and thermal papercharacteristics.5.6 Metallographic ExaminationVerification of the ultra-sonic C-scan evaluation must be conducted by destructivemetallographic examination of selected contact assemblies.Scanning at various instrument sensitivities and then
28、cuttingand peeling or mounting of contacts can provide good under-standing and correlation of results for the technician.5.7 Operator TrainingQualify the skill level of ultrasonictechnicians according to the guidelines of the American Soci-ety for Nondestructive Testing. (See SNT-TC-1A.) Compe-tence
29、 in metallographic examination and the use of areaestimating templates is also required.6. Precision and Bias6.1 PrecisionThe expected closeness of agreement isbased on tests performed during 19801982 by a number ofexperienced industry laboratories (see Table 1 and Table 2).7Janitzki, A. S., and Sch
30、aefer, B., “The Influence of the Quality of Brazing onthe Erosion of Contacts,” Proceedings of the 9th International Conference onElectrical Contact, 1978, pp. 389394.TABLE 1 First Round Robin Test Results for Brazed and Welded Electrical Contact AssembliesLot/SampleNumberTotalContactArea (in.2)Unbo
31、nded Area (in.2)Aby Laboratory NumberMean Range123456Brazed1/9 0.345 0.036 0.036 0.024 0.024 0.036 0.030 0.031 0.0122/24 0.097 0.008 0.016 0.016 0.012 0.008 0.024 0.014 0.0163/19 0.091 0.010 0.010 0.010 0.000 0.010 0.020 0.010 0.0204/4 0.309 0.039 0.026 0.104 0.052 0.104 0.156 0.080 0.1305/34 0.309
32、0.039 0.013 0.091 0.078 0.078 0.039 0.056 0.0786/20 0.309 0.156 0.208 0.182 0.182 0.260 0.260 0.208 0.104Percussion welded7/6 0.309 0.156 0.234 0.234 0.290 0.286 0.286 0.248 0.134Resolution of Fabricated Standards with Flat Bottomed Hole 0.015 In. Diameter2/STD.5/STD.0.0160.0160.0220.0000.0700.0700.
33、0700.0700.0100.0200.025.0.0360.0350.0600.070A1in.2= 645 mm2.B 773 96 (2002)e12These laboratories were all given the same parts, standards, andguidelines and involved various equipment that can be consid-ered standard in the industry.6.1.1 Table 1 provides reproducibility data from six differ-ent lab
34、oratories which examined the same seven brazed con-tacts taken from seven different lots and two of the standardsused during this study.6.1.2 Table 2 provides repeatability data from the same sixlaboratories which subsequently examined the same two con-tact assemblies taken from two of the original
35、seven lots andthe same two original standards.6.1.3 This data shows much better relative correlationamong laboratories in regard to grading the specimens in termsof unbonded area than in correlation of absolute values forunbonded area.6.2 BiasSince there is no accepted standard or referencematerial
36、suitable for determining the systematic error for thistest method of measuring bonded area, no statement on biascan be made.7. Keywords7.1 bond evaluation; braze evaluation; C-scan; contact as-semblies; electrical contacts; ultrasonic C-scan; unltrasonictestingASTM International takes no position re
37、specting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This
38、 standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Inter
39、national Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown b
40、elow.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-955
41、5 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 2 Second Round-Robin Test Results for Brazed Electrical Contact AssembliesLot/SampleNumberTotalContactArea (in.2)Unbonded Area (in.2)Aby Laboratory NumberMean Range123456Brazed2/255/340.0970.3090.0060.020.0.0060.0390.0120.0780.0040.0200.0160.0260.0090.0370.0100.058Resolution of Fabricated Standards with Flat Bottomed Hole 0.015 In. Diameter2/STD.5/STD.0.0200.024.0.0700.0700.0700.0700.020.0.0300.0700.0420.0590.0520.046B 773 96 (2002)e13
