ASTM_B_773_-_96_2008.pdf

Designation:B77396(Reapproved 2008)Standard Guide forUltrasonic C-Scan Bond Evaluation of Brazed or WeldedElectrical Contact Assemblies1This standard is issued under the fixed designation B773;the number immediately following the designation indicates the year oforiginal adoption or,in the case 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.INTRODUCTIONThis guidance document is the 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.2,3The 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 reducing 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 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 its use.It is theresponsibility of the user of this standard to become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet(MSDS)for this product/materialas provided by the manufacturer,to establish appropriatesafety and health practices,and determine the applicability ofregulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:4E214 Practice for Immersed Ultrasonic Testing by the Re-flection Method Using Pulsed Longitudinal Waves(With-drawn 2007)5E500 Standard Definitions of Terms Relating to UltrasonicTesting(Withdrawn 1990)5E1001 Practice for Detection and Evaluation of Discontinui-ties by the Immersed Pulse-Echo Ultrasonic MethodUsing Longitudinal Waves2.2 American Society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 pulse-echo technique isemployed as an ultrasonic testing method which displaysreflected energy pulses.A Piezoelectric transducer(typically1This guide is under the jurisdiction of ASTM Committee B02 on NonferrousMetals and Alloys and is the direct responsibility of Subcommittee B02.11 onElectrical Contact Test Methods.Current edition approved March 1,2008.Published March 2008.Originallyapproved in 1987.Last previous edition approved in 2002 as B773 96(2002)1.DOI:10.1520/B0773-96R08.2Buckley,R.I.,Commey,R.R.,Jr.,and Popat,P.V.,“Nondestructive UltrasonicInspection 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,1979,pp.209213.4For 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.5The last approved version of this historical standard is referenced onwww.astm.org.6Available fromAmerican Society for Nondestructive Testing(ASNT),P.O.Box28518,1711 Arlingate Ln.,Columbus,OH 43228-0518,http:/www.asnt.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesNOTICE:This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International(www.astm.org)for the latest information1 1525 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 also 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 E214 and E1001.)3.2 C-ScanThe amplified electrical 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,thegated electrical signals are then used to describe a two-dimensional plan view of defects in the interior