ASTM_E_2491_-_13.pdf

Designation:E249113Standard Guide forEvaluating Performance Characteristics of Phased-ArrayUltrasonic Testing Instruments and Systems1This standard is issued under the fixed designation E2491;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.1.Scope*1.1 This guide describes procedures for evaluating someperformance characteristics of phased-array ultrasonic exami-nation instruments and systems.1.2 Evaluation of these characteristics is intended to be usedfor comparing instruments and systems or,by periodicrepetition,for detecting long-term changes in the characteris-tics of a given instrument or system that may be indicative ofimpending failure,and which,if beyond certain limits,willrequire corrective maintenance.Instrument characteristicsmeasured in accordance with this guide are expressed in termsthat relate to their potential usefulness for ultrasonic examina-tions.Other electronic instrument characteristics in phased-array units are similar to non-phased-array units and may bemeasured as described in Guide E1065 or E1324.1.3 Ultrasonic examination systems using pulsed-wavetrains and A-scan presentation(rf or video)may be evaluated.1.4 This guide establishes no performance limits for exami-nation systems;if such acceptance criteria are required,thesemust be specified by the using parties.Where acceptancecriteria are implied herein they are for example only and aresubject to more or less restrictive limits imposed by customersand end users controlling documents.1.5 The specific parameters to be evaluated,conditions andfrequency of test,and report data required,must also bedetermined by the user.1.6 This guide may be used for the evaluation of a completeexamination system,including search unit,instrument,interconnections,scanner fixtures and connected alarm andauxiliary devices,primarily in cases where such a system isused repetitively without change or substitution.This guide isnot intended to be used as a substitute for calibration orstandardization of an instrument or system to inspect any givenmaterial.1.7 Required test apparatus includes selected test blocks andposition encoders in addition to the instrument or system to beevaluated.1.8 Precautions relating to the applicability of the proce-dures and interpretation of the results are included.1.9 Alternate procedures,such as examples described in thisdocument,or others,may only be used with customer approval.1.10 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.11 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 limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E317 Practice for Evaluating Performance Characteristics ofUltrasonic Pulse-Echo Testing Instruments and Systemswithout the Use of Electronic Measurement InstrumentsE494 Practice for Measuring Ultrasonic Velocity in Materi-alsE1065 Practice for Evaluating Characteristics of UltrasonicSearch UnitsE1316 Terminology for Nondestructive ExaminationsE1324 Guide for Measuring Some Electronic Characteristicsof Ultrasonic Testing Instruments3.Terminology3.1 Refer to Terminology E1316 for definitions of terms inthis guide.4.Summary of Guide4.1 Phased-array instruments and systems have similar in-dividual components as are found in traditional ultrasonic1This guide is under the jurisdiction of ASTM Committee E07 on Nondestruc-tive Testing and is the direct responsibility of Subcommittee E07.06 on UltrasonicMethod.Current edition approved June 1,2013.Published June 2013.Originallyapproved in 2006.Last previous edition approved in 2008 as E2491-08.DOI:10.1520/E2491-13.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 systems that are based on single channel or multiplexedpulse-echo units.These include pulsers,receivers,probes andinterconnecting cables.The most significant difference is thatphased-array systems form the transmitted ultrasonic pulse byconstructive phase interference from the wavelets formed offthe individually pulsed elements of the phased-array probes.4.2 Each phased-array probe consists of a series of individu-ally wired elements that are activated separately using aprogrammable time delay pattern.Varying the num