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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DRAFT FOR DEVELOPMENT DD ENV 583-6:2000 IC
2、S 19.100 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Non-destructive testing Ultrasonic examination Part 6: Time-of-flight diffraction technique as a method for detection and sizing of discontinuities Licensed Copy: London South Bank University, London South Bank Universit
3、y, Mon Dec 11 01:22:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This Draft for Development, having been prepared under the direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 July 2000 BSI 07-2000 ISBN 0 580 34871
4、7 DD ENV 583-6:2000 Amendments issued since publication Amd. No.DateComments National foreword This Draft for Development is the official English language version of ENV 583-6:2000. During the development of ENV 583-6, the UK expressed concern about some of its provisions. Particular attention is dr
5、awn to the points outlined in national annex NA. Attention is also drawn to the related British Standard BS 7706:1993. This publication is not to be regarded as a British Standard. The UK participation in its preparation was entrusted to Technical Committee WEE/46, Non-destructive testing, which has
6、 the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list
7、of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled International
8、Standards Correspondence Index, or by using the Find facility of the BSI Standards Electronic Catalogue. Summary of pages This document comprises a front cover, an inside front cover, the ENV title page, pages 2 to 15 and a back cover. The BSI copyright notice displayed in this document indicates wh
9、en the document was last issued. Licensed Copy: London South Bank University, London South Bank University, Mon Dec 11 01:22:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretari
10、at: rue de Stassart 36, B-1050 Brussels 2000 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. ENV 583-6:2000 E EUROPEAN PRESTANDARDENV 583-6 PRE NORME EUROPEENNE EUROPA ISCHE VORNORM January 2000 ICS 19.100 English version Non-destruct
11、ive testing Ultrasonic examination Part6: Time-of-flight diffraction technique as a method for detection and sizing of discontinuities Essais non destructifs Contro le ultrasonore Partie 6: Technique de diffraction du temps de vol utilise e comme me thode de de tection et de dimensionnement des disc
12、ontinuite s Zersto rungsfreie Pru fung Ultraschallpru fung Teil 6: Beugungslaufzeittechnik, ein Technik zum Auffinden und Ausmessen von Inhomogenita ten This European Prestandard (ENV) was approved by CEN on 21 May 1997 as a prospective standard for provisional application. The period of validity of
13、 this ENV is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the ENV can be converted into a European Standard. CEN members are required to announce the existence of this ENV in the same way as for
14、an EN and to make the ENV available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the ENV) until the final decision about the possible conversion of the ENV into an EN is reached. CEN members are the national stan
15、dards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: London South Bank University, London South Bank University, Mon Dec 11 01:22:
16、01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 2 ENV 583-6:2000 BSI 07-2000 Foreword This European Prestandard has been prepared by Technical Committee CEN/TC 138, Non-destructive testing, the Secretariat of which is held by AFNOR. According to the CEN/CENELEC Internal Regulations, the national
17、standards organizations of the following countries are bound to announce this European Prestandard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. EN 5
18、83, Non-destructive testing Ultrasonic examination consists of the following parts: EN 583-1, Non-destructive testing Ultrasonic examination Part 1: General principles. EN 583-2, Non-destructive testing Ultrasonic examination Part 2: Sensitivity and range setting. EN 583-3, Non-destructive testing U
19、ltrasonic examination Part 3: Transmission technique. EN 583-4, Non-destructive testing Ultrasonic examination Part 4: Examination for discontinuities perpendicular to the surface. EN 583-5, Non-destructive testing Ultrasonic examination Part 5: Characterization and sizing of discontinuities. ENV 58
20、3-6, Non-destructive testing Ultrasonic examination Part 6: Time-of-flight diffraction technique as a method for detection and sizing of discontinuities. Contents Page Foreword2 1Scope3 2Normative references3 3Definitions and symbols3 4General4 4.1Principle of the technique4 4.2Requirements for surf
21、ace condition and couplant4 4.3Materials and process type6 5Qualification of personnel6 6Equipment requirements6 6.1Ultrasonic equipment and display6 6.2Ultrasonic probes6 6.3Scanning mechanisms8 7Equipment set-up procedures8 7.1General8 7.2Probe choice and probe separation9 7.3Time window setting9
22、7.4Sensitivity setting9 7.5Scan resolution setting9 7.6Setting of scanning speed9 7.7Checking system performance9 8Interpretation and analysis of data10 8.1Basic analysis of discontinuities10 8.2Detailed analysis of discontinuities11 9Detection and sizing in complex geometries12 10Limitations of the
23、 technique12 10.1 Precision and resolution12 10.2 Dead zones13 11TOFD examination without data recording13 12Examination procedure13 13Examination report13 Annex A (normative) Reference blocks14 Licensed Copy: London South Bank University, London South Bank University, Mon Dec 11 01:22:01 GMT+00:00
24、2006, Uncontrolled Copy, (c) BSI Page 3 ENV 583-6:2000 BSI 07-2000 1 Scope This European Prestandard defines the general principles for the application of the Time-of-flight diffraction (TOFD) technique for both detection and sizing of discontinuities in low alloyed carbon steel components. It could
25、 also be used for other types of materials, provided the application of the TOFD technique is performed with necessary consideration of geometry, acoustical properties of the materials and the sensitivity of the examination. Although it is applicable, in general terms, to discontinuities in material
26、s and applications covered by EN 583-1, it contains references to the application on welds. This approach has been chosen for reasons of clarity as to the ultrasonic probe positions and directions of scanning. Unless otherwise specified in the referencing documents, the minimum requirements of this
27、Prestandard are applicable. Unless explicitly stated otherwise, this Prestandard is applicable to the following product classes as defined in EN 583-2: class 1, without restrictions; classes 2 and 3, restrictions will apply as stated in clause 9. The inspection of products of classes 4 and 5 will re
28、quire special procedures. These are addressed in clause 9 as well. 2 Normative references This European Prestandard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are list
29、ed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Prestandard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 473, Qualification and
30、 certification of NDT personnel General principles. EN 583-1, Non-destructive testing Ultrasonic examination Part 1: General principles. EN 583-2, Non-destructive testing Ultrasonic examination Part 2: Sensitivity and range setting. EN 12668-1, Ultrasonic examination Characterization and verificatio
31、n of ultrasonic examination equipment Part 1: Instruments. EN 12668-2, Ultrasonic examination Characterization and verification of ultrasonic examination equipment Part 2: Probes. EN 12668-3, Ultrasonic examination Characterization and verification of ultrasonic examination equipment Part 3: Combine
32、d equipment. 3 Definitions and symbols TOFD Time-of-flight diffraction. xcoordinate parallel to the scanning surface, and parallel to a predetermined reference line. In case of weld inspection this reference line should coincide with the weld. The origin of the axes may be defined as best suits the
33、specimen under examination (see Figure 1); Dximperfection length; ycoordinate parallel to the scanning surface, perpendicular to the predetermined reference line (see Figure 1); dyerror in lateral position; zcoordinate perpendicular to the scanning surface (see Figure 1); Dzimperfection height; ddep
34、th of a imperfection tip below the scanning surface; dderror in depth; Ddsscanning-surface dead zone; Ddwbackwall dead zone; csound velocity; dcerror in sound velocity; Rspatial resolution; ttime-of-flight from the transmitter to the receiver; Dttime-of-flight difference between the lateral wave and
35、 a second ultrasonic signal; dterror in time-of-flight; tdtime-of-flight at depth d; tplength (in time) of the acoustical pulse up to an amplitude of 10 % of the maximum; twtime-of-flight of the backwall echo; Shalf the distance between the index points of two ultrasonic probes; dSerror in half the
36、probe separation; Wwall thickness; dead zonezone where indications may be obscured due to the presence of signals of geometrical origin; back wall dead zone extra dead zone where signals may be obscured by the presence of the back wall echo; A-scandisplay of the ultrasonic signal amplitude as a func
37、tion of time; B-scandisplay of the time-of-flight of the ultrasonic signal as a function of probe displacement; non-parallel scan scan perpendicular to the ultrasonic beam direction (see Figure 4); parallel scan scan parallel to the ultrasonic beam direction (see Figure 5). Licensed Copy: London Sou
38、th Bank University, London South Bank University, Mon Dec 11 01:22:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 4 ENV 583-6:2000 BSI 07-2000 Figure 1 Coordinate definition 4 General 4.1 Principle of the technique The TOFD technique relies on the interaction of ultrasonic waves with the tips of
39、 discontinuities. This interaction results in the emission of diffracted waves over a large angular range. Detection of the diffracted waves makes it possible to establish the presence of the imperfection. The time-of-flight of the recorded signals is a measure for the height of the imperfection, th
40、us enabling sizing of the defect. The dimension of the imperfection is always determined from the time-of-flight of the diffracted signals. The signal amplitude is not used in size estimation. The basic configuration for the TOFD technique consists of a separate ultrasonic transmitter and receiver (
41、see Figure 2). Wide-angle beam compression wave probes are normally used since the diffraction of ultrasonic waves is only weakly dependent on the orientation of the imperfection tip. This enables the inspection of a certain volume in one scan. However, restrictions apply to the size of the volume t
42、hat can be inspected during a single scan (see 7.2). The first signal to arrive at the receiver after emission of an acoustic pulse is usually the lateral wave which travels just beneath the upper surface of the test specimen. In the absence of discontinuities the second signal to arrive at the rece
43、iver is the backwall echo. These two signals are normally used for reference purposes. If mode conversion is neglected, any signals generated by discontinuities in the material should arrive between the lateral wave and the backwall echo, since the latter two correspond, respectively, to the shortes
44、t and longest paths between transmitter and receiver. For similar reasons the diffracted signal generated at the upper tip of an imperfection will arrive before the signal generated at the lower tip of the imperfection. A typical pattern of indications (A-scan) is shown in Figure 3. The height of th
45、e imperfection can be deduced from the difference in time-of-flight of the two diffracted signals (see 8.1.5). Note the phase reversal between the lateral wave and the backwall echo, and between echoes of the upper and lower tip of the imperfection. Where access to both surfaces of the specimen is p
46、ossible and flaws are distributed throughout the specimen thickness, scanning from both surfaces will improve the overall precision, particularly in regard to flaws near the surfaces. 4.2 Requirements for surface condition and couplant Care shall be taken that the surface condition meets at least th
47、e requirements stated in EN 583-1. Since the diffracted signals may be weak, the degradation of signal quality due to poor surface condition will have a severe impact on inspection reliability. Licensed Copy: London South Bank University, London South Bank University, Mon Dec 11 01:22:01 GMT+00:00 2
48、006, Uncontrolled Copy, (c) BSI Page 5 ENV 583-6:2000 BSI 07-2000 Legend 1 2 a b Transmitter Receiver Lateral wave Upper tip c d e f Included angle Imperfection Lower tip Back wall echo Figure 2 Basic TOFD configuration Legend X Y a Amplitude Time Lateral wave b c d Upper tip Back wall echo Lower ti
49、p Figure 3 Schematic A-scan of embedded imperfection Licensed Copy: London South Bank University, London South Bank University, Mon Dec 11 01:22:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 6 ENV 583-6:2000 BSI 07-2000 Different coupling media can be used, but their type shall be compatible with the materials to be examined. Examples are: water, possibly containing an agent (wetting, anti-freeze, corrosion inhibitor), contact paste, oil, grease, cellulose paste containing wa