Non-destructive testing - Ultrasonic testing - Characterization and sizing of discontinuities (ISO 16827:2012)

EN ISO 16827 specifies the general principles and techniques for the characterization and sizing of previously detected discontinuities in order to ensure their evaluation against applicable acceptance criteria. It is applicable, in general terms, to discontinuities in those materials and applications covered by ISO 16810.

Zerstörungsfreie Prüfung - Ultraschallprüfung - Beschreibung und Größenbestimmung von Inhomogenitäten (ISO 16827:2012)

Dieses Dokument legt die allgemeinen Grundsätze und Techniken zur Beschreibung und Größenbestimmung von vorher nachgewiesenen Inhomogenitäten fest, um deren Bewertung im Vergleich zu den gültigen Zulässigkeitskriterien sicherzustellen. Es ist allgemein für Inhomogenitäten in den Werkstoffen und für die Anwendungen anwendbar, die in ISO 16810 behandelt werden.

Essais non destructifs - Contrôle par ultrasons - Caractérisation et dimensionnement des discontinuités (ISO 16827:2012)

L'ISO 16827:2012 décrit les principes généraux et les techniques pour la caractérisation et le dimensionnement des discontinuités détectées au préalable afin de les évaluer correctement par rapport aux critères d'acceptation applicables. Elle s'applique, en termes génériques, aux discontinuités des matériaux et applications couvertes par l'ISO 16810.

Neporušitvene preiskave - Ultrazvočne preiskave - Karakterizacija in velikosti nezveznosti (ISO 16827:2012)

Standard EN ISO 16827 določa osnovna načela in tehnike za karakterizacijo in določanje velikosti prej odkritih nezveznosti, da se jih oceni na podlagi veljavnih kriterijev sprejemljivosti. Standard v splošnem velja za nezveznosti v tistih materialih in uporabah, ki jih zajema standard ISO 16810.

General Information

Status
Published
Public Enquiry End Date
29-Nov-2013
Publication Date
30-Jun-2014
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
29-May-2014
Due Date
03-Aug-2014
Completion Date
01-Jul-2014

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Zerstörungsfreie Prüfung - Ultraschallprüfung - Beschreibung und Größenbestimmung von Inhomogenitäten (ISO 16827:2012)Essais non destructifs - Contrôle par ultrasons - Caractérisation et dimensionnement des discontinuités (ISO 16827:2012)Non-destructive testing - Ultrasonic testing - Characterization and sizing of discontinuities (ISO 16827:2012)19.100Neporušitveno preskušanjeNon-destructive testingICS:Ta slovenski standard je istoveten z:EN ISO 16827:2014SIST EN ISO 16827:2014en01-julij-2014SIST EN ISO 16827:2014SLOVENSKI
STANDARDSIST EN 583-5:2001/A1:2004SIST EN 583-5:20011DGRPHãþD



SIST EN ISO 16827:2014



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN ISO 16827
March 2014 ICS 19.100 Supersedes EN 583-5:2000English Version
Non-destructive testing - Ultrasonic testing - Characterization and sizing of discontinuities (ISO 16827:2012)
Essais non destructifs - Contrôle par ultrasons - Caractérisation et dimensionnement des discontinuités (ISO16827:2012)
Zerstörungsfreie Prüfung - Ultraschallprüfung - Beschreibung und Größenbestimmung von Inhomogenitäten (ISO 16827:2012) This European Standard was approved by CEN on 9 February 2014.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 16827:2014 ESIST EN ISO 16827:2014



EN ISO 16827:2014 (E) 2 Contents
Foreword .3 SIST EN ISO 16827:2014



EN ISO 16827:2014 (E) 3 Foreword The text of ISO 16827:2012 has been prepared by Technical Committee ISO/TC 135 “Non-destructive testing” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 16827:2014 by Technical Committee CEN/TC 138 “Non-destructive testing” the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 2014, and conflicting national standards shall be withdrawn at the latest by September 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 583-5:2000. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 16827:2012 has been approved by CEN as EN ISO 16827:2014 without any modification.
SIST EN ISO 16827:2014



SIST EN ISO 16827:2014



Reference numberISO 16827:2012(E)© ISO 2012
INTERNATIONAL STANDARD ISO16827First edition2012-04-01Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities Essais non destructifs — Contrôle par ultrasons — Caractérisation et dimensionnement des discontinuités
SIST EN ISO 16827:2014



ISO 16827:2012(E)
COPYRIGHT PROTECTED DOCUMENT
©
ISO 2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56  CH-1211 Geneva 20 Tel.
+ 41 22 749 01 11 Fax
+ 41 22 749 09 47 E-mail
copyright@iso.org Web
www.iso.org Published in Switzerland
ii
© ISO 2012 – All rights reserved
SIST EN ISO 16827:2014



ISO 16827:2012(E) © ISO 2012 – All rights reserved iii Contents Page Foreword.v 1 Scope.1 2 Normative references.1 3 Principles of characterization of discontinuities.1 3.1 General.1 3.2 Requirements for surface condition.2 4 Pulse echo techniques.2 4.1 General.2 4.2 Location of discontinuity.2 4.3 Orientation of discontinuity.2 4.4 Assessment of multiple indications.3 4.5 Shape of discontinuity.3 4.5.1 Simple classification.3 4.5.2 Detailed classification of shape.4 4.6 Maximum echo height of indication.4 4.7 Size of discontinuity.4 4.7.1 General.4 4.7.2 Maximum echo height techniques.4 4.7.3 Probe movement sizing techniques.5 4.7.4 Selection of sizing techniques.5 4.7.5 Sizing techniques with focussing ultrasonic probes.6 4.7.6 Use of mathematical algorithms for sizing.6 4.7.7 Special sizing techniques.6 5 Transmission technique.7 5.1 General.7 5.2 Location of discontinuity.7 5.3 Evaluation of multiple discontinuities.7 5.4 Reduction of
signal amplitude.8 5.5 Sizing of discontinuity.8 Annex A (normative)
Analysis of multiple indications.12 A.1 Lateral characterisation.12 A.2 Transverse (Through-thickness) characterisation.12 A.3 Shadow technique.12 Annex B (normative)
Techniques for the classification of discontinuity shape.14 B.1 Simple classification.14 B.1.1 General.14 B.1.2 Reconstruction technique.14 B.1.3 Echo envelope technique.14 B.2 Detailed classification.14 B.2.1 General.14 B.2.2 Echodynamic pattern technique.15 B.2.3 Directional reflectivity.17 B.3 Combination of data.17 Annex C (informative)
Maximum echo height sizing technique.25 C.1 Distance-gain-size (DGS) technique.25 C.1.1 Principle.25 C.1.2 Applications and limitations.25 C.2 Distance-amplitude-correction (DAC) curve technique.25 C.2.1 Principle.25 Introduction.vi SIST EN ISO 16827:2014



ISO 16827:2012(E) iv © ISO 2012 – All rights reserved
C.2.2 Applications and limitations.26 Annex D (normative)
Probe movement sizing techniques.27 D.1 Fixed amplitude level techniques.27 D.1.1 Principle.27 D.1.2 Application and limitations.27 D.2 6 dB drop from maximum technique.27 D.2.1 Principle.27 D.2.2 Application and limitations.27 D.3 12 dB or 20 dB drop from maximum technique.28 D.3.1 Principle.28 D.3.2 Application and limitations.28 D.4 Drop to noise level technique.28 D.4.1 Principle.28 D.4.2 Application and limitations.28 D.5 6 dB drop tip location technique.29 D.5.1 Principle.29 D.5.2 Application and limitations.29 D.6 Beam axis tip location technique.29 D.6.1 Principle.29 D.6.2 Application and limitations.29 D.7 20 dB drop tip location technique.30 D.7.1 Principle.30 D.7.2 Application and limitations.30 Annex E (normative)
Iterative sizing technique.39 E.1 Scope.39 E.2 Normal incidence testing.39 E.2.1 Principle.39 E.2.2 Adjustment of gain.39 E.2.3 Procedure.39 E.3 Oblique incidence testing.40 Annex F (normative)
Mathematical algorithms for the estimation of the actual size of a discontinuity.45 F.1 Large planar discontinuities.45 F.2 Small planar discontinuities.46 F.3 Planar discontinuities in a cylindrical test object.48 Annex G (informative)
Examples of special sizing techniques.50 G.1 Tip diffraction techniques.50 G.2 Synthetic aperture focussing technique (SAFT).51
SIST EN ISO 16827:2014



ISO 16827:2012(E) © ISO 2012 – All rights reserved v Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 16827 was prepared by Technical Committee ISO/TC 135, Non-destructive testing, Subcommittee SC 3, Ultrasonic testing.
SIST EN ISO 16827:2014



ISO 16827:2012(E) vi © ISO 2012 – All rights reserved Introduction This International Standard is based on EN 583-5:2000+A1:2003, Non-destructive testing — Ultrasonic examination — Part 5: Characterization and sizing of discontinuities. The following International Standards are linked. ISO 16810, Non-destructive testing — Ultrasonic testing — General principles ISO 16811, Non-destructive testing — Ultrasonic testing — Sensitivity and range setting ISO 16823, Non-destructive testing — Ultrasonic testing — Transmission technique ISO 16826, Non-destructive testing — Ultrasonic testing — Examination for discontinuities perpendicular to the surface ISO 16827, Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities ISO 16828, Non-destructive testing — Ultrasonic testing — Time-of-flight diffraction technique as a method for detection and sizing of discontinuities
SIST EN ISO 16827:2014



1 1 Scope This document specifies the general principles and techniques for the characterization and sizing of previously detected discontinuities in order to ensure their evaluation against applicable acceptance criteria. It is applicable, in general terms, to discontinuities in those materials and applications covered by ISO 1S810.
2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 16810:2012, Non-destructive testing — Ultrasonic testing — General principles ISO 16811, Non-destructive testing — Ultrasonic testing — Sensitivity and range setting ISO 16823, Non-destructive testing — Ultrasonic testing — Transmission technique ISO 16828, Non-destructive testing — Ultrasonic testing — Time-of-flight diffraction technique as a method for detection and sizing of discontinuities ISO 23279, Non-destructive testing of welds — Ultrasonic testing — Characterization of indications in welds 3 Principles of characterization of discontinuities 3.1 General Characterization of a discontinuity involves the determination of those features which are necessary for its evaluation with respect to known acceptance criteria.
Characterization of a discontinuity may include: a) determination of basic ultrasonic parameters (echo height, time of flight); b) determination of its basic shape and orientation; c) sizing, which may take the form of either: i) the measurement of one or more dimensions (or area/volume), within the limitations of the methods; or ii) the measurement of some agreed parameter e.g. echo height, where this is taken as representative of its physical size; d) location e.g. the proximity to the surface or to other discontinuities; e) determination of any other parameters or characteristics that may be necessary for complete evaluation; INTERNATIONAL STANDARD ISO 16827:2012(E) Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities © ISO 2012 – All rights reservedSIST EN ISO 16827:2014



2
f) assessment of probable nature, e.g. crack or inclusion, where adequate knowledge of the test object and its manufacturing history makes this feasible. Where the examination of a test object in accordance with the principles of ISO 16810 yields sufficient data on the discontinuity for its evaluation against the applicable acceptance criteria, no further characterization is necessary.
The techniques used for characterization shall be specified in conjunction with the applicable acceptance criteria. 3.2 Requirements for surface condition The surface finish and profile shall be such that it permits sizing of discontinuities with the desired accuracy. In general the smoother and flatter the surface the more accurate the results will be.
For most practical purposes a surface finish of Ra = 6,3 µm for machined surfaces and 12,5 µm for shotblasted surfaces are recommended. The gap between the probe and the surface should not exceed 0,5 mm. The above surface requirements should normally be limited to those areas from which sizing is to be carried out as, in general, they are unnecessary for discontinuity detection.
The method of surface preparation shall not produce a surface that gives rise to a high level of surface noise.
4 Pulse echo techniques 4.1 General The principal ultrasonic characteristics/parameters of a discontinuity that are most commonly used for evaluation by the pulse echo techniques are described in 4.2 to 4.7 inclusive. The characteristics/parameters to be determined shall be defined in the applicable standard or any relevant contractual document, and shall meet the requirements of 10.1 of ISO 16810:2012. 4.2 Location of discontinuity The location of a discontinuity is defined as its position within a test object with respect to an agreed system of reference co-ordinates. It shall be determined in relation to one or more datum points and with reference to the index point and beam angle of the probe, and measurement of the probe position and beam path length at which the maximum echo height is observed.
Depending on the geometry of the test object under examination, and the type of discontinuity, it may be necessary to confirm the location of the discontinuity from another direction, or with another probe angle, to ensure that the echo is not caused e.g. by a wave mode change at a geometrical feature of the test object.
4.3 Orientation of discontinuity The orientation of a discontinuity is defined as the direction or plane along which the discontinuity has its major axis (axes) with respect to a datum reference on the test object.
The orientation can be determined by a geometrical reconstruction analogous to that described for location, with the difference that more beam angles and/or scanning directions are generally necessary than for simple location.
The orientation may also be determined from observation of the scanning direction at which the maximum echo height is obtained.
ISO 16827:2012(E) © ISO 2012 – All rights reservedSIST EN ISO 16827:2014



3 In several applications, the precise determination of the discontinuity orientation in space is not required, only the determination of the projection of the discontinuity onto one or more pre-established planes and/or sections within the test object.
4.4 Assessment of multiple indications The method for distinguishing between single and multiple discontinuities may be based on either qualitative assessment or quantitative criteria. The qualitative determination consists of ascertaining, through the observation of the variations of the ultrasonic indications, whether or not such indications correspond to one or more separate discontinuities. Figure 1 shows typical examples of signals from grouped discontinuities in a forging or casting.
Where acceptance criteria are expressed in terms of maximum allowable dimensions, preliminary quantitative measurements shall be made in order to determine whether separate discontinuities are to be evaluated individually or collectively according to pre-established rules governing the evaluation of the group.
Such rules may be based on the concentration of individual discontinuities within the group, expressed in terms of the total of their lengths, areas or volumes in relation to the overall length, area or volume of the group. Alternatively, the rules may specify the minimum distance between individual discontinuities, often as a ratio of the dimensions of the adjacent discontinuities.
Where a more accurate characterization of a group of indications is required, an attempt may be made to determine whether the echoes arise from a series of closely spaced but separate discontinuities, or from a single continuous discontinuity having a number of separate reflecting facets, using the techniques described in Annex A.
4.5 Shape of discontinuity 4.5.1 Simple classification There are a limited number of basic reflector shapes that may be identified by ultrasonic testing. In many cases evaluation against the applicable acceptance criteria only requires a relatively simple classification, described in B.1. According to this, the discontinuity is classified as either: 1) point, i.e. having no significant extent in any direction; 2) elongated, i.e. having a significant extent in one direction only; 3) complex, i.e. having a significant extent in more than one direction. When required, this classification may be sub-divided into: a) planar, i.e. having a significant extent in 2 directions only, and b) volumetric, i.e., having a significant extent in 3 directions.
Depending upon the requirements of the acceptance standard, either: a) separate acceptance criteria may apply to each of the above classifications, or b) the discontinuity, independently of its point, elongated or complex configuration, is projected on one or more pre-established sections, and each projection is conservatively treated as a crack-like planar discontinuity. Simple classification will normally be limited to the use of those probes and techniques specified in the examination procedure. Additional probes or techniques shall only be used where agreed.
ISO 16827:2012(E) © ISO 2012 – All rights reservedSIST EN ISO 16827:2014



4
4.5.2 Detailed classification of shape In order to correctly identify the discontinuity types specified in the acceptance criteria, or to make a correct fitness-for-purpose evaluation, it may be necessary to make a more detailed assessment of the shape of the discontinuity. Guidance on the methods that may be used for a more detailed classification is contained in B.O. It can require the use of additional probes and scanning directions to those specified in the examination procedure for the detection of discontinuities, and can also be aided by the use of the special techniques in Annexes E, F and G. Classification of discontinuity shape will be limited to the determination of those discontinuity shapes which are necessary for the correct evaluatio
...

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Zerstörungsfreie Prüfung - Ultraschallprüfung - Beschreibung und Größenbestimmung von Inhomogenitäten (ISO 16827:2012)Essais non destructifs - Contrôle par ultrasons - Caractérisation et dimensionnement des discontinuités (ISO 16827:2012)Non-destructive testing - Ultrasonic testing - Characterization and sizing of discontinuities (ISO 16827:2012)19.100Neporušitveno preskušanjeNon-destructive testingICS:Ta slovenski standard je istoveten z:FprEN ISO 16827kSIST FprEN ISO 16827:2013en,de01-november-2013kSIST FprEN ISO 16827:2013SLOVENSKI
STANDARD



kSIST FprEN ISO 16827:2013



EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
FINAL DRAFT
FprEN ISO 16827
August 2013 ICS 19.100 Will supersede EN 583-5:2000English Version
Non-destructive testing - Ultrasonic testing - Characterization and sizing of discontinuities (ISO 16827:2012)
Essais non destructifs - Contrôle par ultrasons - Caractérisation et dimensionnement des discontinuités (ISO 16827:2012)
Zerstörungsfreie Prüfung - Ultraschallprüfung - Beschreibung und Größenbestimmung von Inhomogenitäten (ISO 16827:2013) This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee CEN/TC 138.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. FprEN ISO 16827:2013: EkSIST FprEN ISO 16827:2013



FprEN ISO 16827:2013 (E) 2 Contents
Page Foreword .3
kSIST FprEN ISO 16827:2013



FprEN ISO 16827:2013 (E) 3 Foreword The text of ISO 16827:2012 has been prepared by Technical Committee ISO/TC 135 “Non-destructive testing” of the International Organization for Standardization (ISO) and has been taken over as FprEN ISO 16827:2013 by Technical Committee CEN/TC 138 “Non-destructive testing” the secretariat of which is held by AFNOR. This document is currently submitted to the Unique Acceptance Procedure. This document will supersede EN 583-5:2000. Endorsement notice The text of ISO 16827:2012 has been approved by CEN as FprEN ISO 16827:2013 without any modification.
kSIST FprEN ISO 16827:2013



kSIST FprEN ISO 16827:2013



Reference numberISO 16827:2012(E)© ISO 2012
INTERNATIONAL STANDARD ISO16827First edition2012-04-01Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities Essais non destructifs — Contrôle par ultrasons — Caractérisation et dimensionnement des discontinuités
kSIST FprEN ISO 16827:2013



ISO 16827:2012(E)
COPYRIGHT PROTECTED DOCUMENT
©
ISO 2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56  CH-1211 Geneva 20 Tel.
+ 41 22 749 01 11 Fax
+ 41 22 749 09 47 E-mail
copyright@iso.org Web
www.iso.org Published in Switzerland
ii
© ISO 2012 – All rights reserved
kSIST FprEN ISO 16827:2013



ISO 16827:2012(E) © ISO 2012 – All rights reserved iii Contents Page Foreword.v 1 Scope.1 2 Normative references.1 3 Principles of characterization of discontinuities.1 3.1 General.1 3.2 Requirements for surface condition.2 4 Pulse echo techniques.2 4.1 General.2 4.2 Location of discontinuity.2 4.3 Orientation of discontinuity.2 4.4 Assessment of multiple indications.3 4.5 Shape of discontinuity.3 4.5.1 Simple classification.3 4.5.2 Detailed classification of shape.4 4.6 Maximum echo height of indication.4 4.7 Size of discontinuity.4 4.7.1 General.4 4.7.2 Maximum echo height techniques.4 4.7.3 Probe movement sizing techniques.5 4.7.4 Selection of sizing techniques.5 4.7.5 Sizing techniques with focussing ultrasonic probes.6 4.7.6 Use of mathematical algorithms for sizing.6 4.7.7 Special sizing techniques.6 5 Transmission technique.7 5.1 General.7 5.2 Location of discontinuity.7 5.3 Evaluation of multiple discontinuities.7 5.4 Reduction of
signal amplitude.8 5.5 Sizing of discontinuity.8 Annex A (normative)
Analysis of multiple indications.12 A.1 Lateral characterisation.12 A.2 Transverse (Through-thickness) characterisation.12 A.3 Shadow technique.12 Annex B (normative)
Techniques for the classification of discontinuity shape.14 B.1 Simple classification.14 B.1.1 General.14 B.1.2 Reconstruction technique.14 B.1.3 Echo envelope technique.14 B.2 Detailed classification.14 B.2.1 General.14 B.2.2 Echodynamic pattern technique.15 B.2.3 Directional reflectivity.17 B.3 Combination of data.17 Annex C (informative)
Maximum echo height sizing technique.25 C.1 Distance-gain-size (DGS) technique.25 C.1.1 Principle.25 C.1.2 Applications and limitations.25 C.2 Distance-amplitude-correction (DAC) curve technique.25 C.2.1 Principle.25 Introduction.vi kSIST FprEN ISO 16827:2013



ISO 16827:2012(E) iv © ISO 2012 – All rights reserved
C.2.2 Applications and limitations.26 Annex D (normative)
Probe movement sizing techniques.27 D.1 Fixed amplitude level techniques.27 D.1.1 Principle.27 D.1.2 Application and limitations.27 D.2 6 dB drop from maximum technique.27 D.2.1 Principle.27 D.2.2 Application and limitations.27 D.3 12 dB or 20 dB drop from maximum technique.28 D.3.1 Principle.28 D.3.2 Application and limitations.28 D.4 Drop to noise level technique.28 D.4.1 Principle.28 D.4.2 Application and limitations.28 D.5 6 dB drop tip location technique.29 D.5.1 Principle.29 D.5.2 Application and limitations.29 D.6 Beam axis tip location technique.29 D.6.1 Principle.29 D.6.2 Application and limitations.29 D.7 20 dB drop tip location technique.30 D.7.1 Principle.30 D.7.2 Application and limitations.30 Annex E (normative)
Iterative sizing technique.39 E.1 Scope.39 E.2 Normal incidence testing.39 E.2.1 Principle.39 E.2.2 Adjustment of gain.39 E.2.3 Procedure.39 E.3 Oblique incidence testing.40 Annex F (normative)
Mathematical algorithms for the estimation of the actual size of a discontinuity.45 F.1 Large planar discontinuities.45 F.2 Small planar discontinuities.46 F.3 Planar discontinuities in a cylindrical test object.48 Annex G (informative)
Examples of special sizing techniques.50 G.1 Tip diffraction techniques.50 G.2 Synthetic aperture focussing technique (SAFT).51
kSIST FprEN ISO 16827:2013



ISO 16827:2012(E) © ISO 2012 – All rights reserved v Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 16827 was prepared by Technical Committee ISO/TC 135, Non-destructive testing, Subcommittee SC 3, Ultrasonic testing.
kSIST FprEN ISO 16827:2013



ISO 16827:2012(E) vi © ISO 2012 – All rights reserved Introduction This International Standard is based on EN 583-5:2000+A1:2003, Non-destructive testing — Ultrasonic examination — Part 5: Characterization and sizing of discontinuities. The following International Standards are linked. ISO 16810, Non-destructive testing — Ultrasonic testing — General principles ISO 16811, Non-destructive testing — Ultrasonic testing — Sensitivity and range setting ISO 16823, Non-destructive testing — Ultrasonic testing — Transmission technique ISO 16826, Non-destructive testing — Ultrasonic testing — Examination for discontinuities perpendicular to the surface ISO 16827, Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities ISO 16828, Non-destructive testing — Ultrasonic testing — Time-of-flight diffraction technique as a method for detection and sizing of discontinuities
kSIST FprEN ISO 16827:2013



1 1 Scope This document specifies the general principles and techniques for the characterization and sizing of previously detected discontinuities in order to ensure their evaluation against applicable acceptance criteria. It is applicable, in general terms, to discontinuities in those materials and applications covered by ISO 1S810.
2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 16810:2012, Non-destructive testing — Ultrasonic testing — General principles ISO 16811, Non-destructive testing — Ultrasonic testing — Sensitivity and range setting ISO 16823, Non-destructive testing — Ultrasonic testing — Transmission technique ISO 16828, Non-destructive testing — Ultrasonic testing — Time-of-flight diffraction technique as a method for detection and sizing of discontinuities ISO 23279, Non-destructive testing of welds — Ultrasonic testing — Characterization of indications in welds 3 Principles of characterization of discontinuities 3.1 General Characterization of a discontinuity involves the determination of those features which are necessary for its evaluation with respect to known acceptance criteria.
Characterization of a discontinuity may include: a) determination of basic ultrasonic parameters (echo height, time of flight); b) determination of its basic shape and orientation; c) sizing, which may take the form of either: i) the measurement of one or more dimensions (or area/volume), within the limitations of the methods; or ii) the measurement of some agreed parameter e.g. echo height, where this is taken as representative of its physical size; d) location e.g. the proximity to the surface or to other discontinuities; e) determination of any other parameters or characteristics that may be necessary for complete evaluation; INTERNATIONAL STANDARD ISO 16827:2012(E) Non-destructive testing — Ultrasonic testing — Characterization and sizing of discontinuities © ISO 2012 – All rights reservedkSIST FprEN ISO 16827:2013



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f) assessment of probable nature, e.g. crack or inclusion, where adequate knowledge of the test object and its manufacturing history makes this feasible. Where the examination of a test object in accordance with the principles of ISO 16810 yields sufficient data on the discontinuity for its evaluation against the applicable acceptance criteria, no further characterization is necessary.
The techniques used for characterization shall be specified in conjunction with the applicable acceptance criteria. 3.2 Requirements for surface condition The surface finish and profile shall be such that it permits sizing of discontinuities with the desired accuracy. In general the smoother and flatter the surface the more accurate the results will be.
For most practical purposes a surface finish of Ra = 6,3 µm for machined surfaces and 12,5 µm for shotblasted surfaces are recommended. The gap between the probe and the surface should not exceed 0,5 mm. The above surface requirements should normally be limited to those areas from which sizing is to be carried out as, in general, they are unnecessary for discontinuity detection.
The method of surface preparation shall not produce a surface that gives rise to a high level of surface noise.
4 Pulse echo techniques 4.1 General The principal ultrasonic characteristics/parameters of a discontinuity that are most commonly used for evaluation by the pulse echo techniques are described in 4.2 to 4.7 inclusive. The characteristics/parameters to be determined shall be defined in the applicable standard or any relevant contractual document, and shall meet the requirements of 10.1 of ISO 16810:2012. 4.2 Location of discontinuity The location of a discontinuity is defined as its position within a test object with respect to an agreed system of reference co-ordinates. It shall be determined in relation to one or more datum points and with reference to the index point and beam angle of the probe, and measurement of the probe position and beam path length at which the maximum echo height is observed.
Depending on the geometry of the test object under examination, and the type of discontinuity, it may be necessary to confirm the location of the discontinuity from another direction, or with another probe angle, to ensure that the echo is not caused e.g. by a wave mode change at a geometrical feature of the test object.
4.3 Orientation of discontinuity The orientation of a discontinuity is defined as the direction or plane along which the discontinuity has its major axis (axes) with respect to a datum reference on the test object.
The orientation can be determined by a geometrical reconstruction analogous to that described for location, with the difference that more beam angles and/or scanning directions are generally necessary than for simple location.
The orientation may also be determined from observation of the scanning direction at which the maximum echo height is obtained.
ISO 16827:2012(E) © ISO 2012 – All rights reservedkSIST FprEN ISO 16827:2013



3 In several applications, the precise determination of the discontinuity orientation in space is not required, only the determination of the projection of the discontinuity onto one or more pre-established planes and/or sections within the test object.
4.4 Assessment of multiple indications The method for distinguishing between single and multiple discontinuities may be based on either qualitative assessment or quantitative criteria. The qualitative determination consists of ascertaining, through the observation of the variations of the ultrasonic indications, whether or not such indications correspond to one or more separate discontinuities. Figure 1 shows typical examples of signals from grouped discontinuities in a forging or casting.
Where acceptance criteria are expressed in terms of maximum allowable dimensions, preliminary quantitative measurements shall be made in order to determine whether separate discontinuities are to be evaluated individually or collectively according to pre-established rules governing the evaluation of the group.
Such rules may be based on the concentration of individual discontinuities within the group, expressed in terms of the total of their lengths, areas or volumes in relation to the overall length, area or volume of the group. Alternatively, the rules may specify the minimum distance between individual discontinuities, often as a ratio of the dimensions of the adjacent discontinuities.
Where a more accurate characterization of a group of indications is required, an attempt may be made to determine whether the echoes arise from a series of closely spaced but separate discontinuities, or from a single continuous discontinuity having a number of separate reflecting facets, using the techniques described in Annex A.
4.5 Shape of discontinuity 4.5.1 Simple classification There are a limited number of basic reflector shapes that may be identified by ultrasonic testing. In many cases evaluation against the applicable acceptance criteria only requires a relatively simple classification, described in B.1. According to this, the discontinuity is classified as either: 1) point, i.e. having no significant extent in any direction; 2) elongated, i.e. having a significant extent in one direction only; 3) complex, i.e. having a significant extent in more than one direction. When required, this classification may be sub-divided into: a) planar, i.e. having a significant extent in 2 directions only, and b) volumetric, i.e., having a significant extent in 3 directions.
Depending upon the requirements of the acceptance standard, either: a) separate acceptance criteria may apply to each of the above classifications, or b) the discontinuity, independently of its point, elongated or complex configuration, is projected on one or more pre-established sections, and each projection is conservatively treated as a crack-like planar discontinuity. Simple classification will normally be limited to the use of those probes and techniques specified in the examination procedure. Additional probes or techniques shall only be used where agreed.
ISO 16827:2012(E) © ISO 2012 – All rights reservedkSIST FprEN ISO 16827:2013



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4.5.2 Detailed classification of shape In order to correctly identify the discontinuity types specified in the acceptance criteria, or to make a correct fitness-for-purpose evaluation, it may be necessary to make a more detailed assessment of the shape of the discontinuity. Guidance on the methods that may be used for a more detailed classification is contained in B.O. It can require the use of additional probes and scanning directions to those specified in the examination procedure for the detection of discontinuities, and can also be aided by the use of the special techniques in Annexes E, F and G. Classification of discontinuity shape will be limited to the determination of those discontinuity shapes which are necessary for the correct evaluation of a discontinuity against the acceptance criteria or other requirements. The validity of such a classification should be proven for the specific application, e.g. materials and configuration of the examination object, examination procedure, type of instrumentation and probes. 4.6 Maximum echo height of indication The maximum echo height from a discontinuity is related to its size, shape and orientation. It is measured by comparison with a given reference level according to the methods described in I
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