SIST EN ISO 11666:2018

Non-destructive testing of welds - Ultrasonic testing - Acceptance levels (ISO 11666:2018)

This document specifies two ultrasonic acceptance levels known as acceptance level 2 (AL 2) and
acceptance level 3 (AL 3) for full penetration welded joints in ferritic steels, which correspond to
ISO 5817:2014, quality levels B and C. An acceptance level corresponding to ISO 5817:2014, quality
level D is not included in this document, as ultrasonic testing is generally not requested for this weld
quality.
These acceptance levels are applicable to testing carried out in accordance with ISO 17640.
This document applies to the testing of full penetration ferritic steel welds, with thicknesses from
8 mm to 100 mm. It can also be used for other types of welds, materials and thicknesses, provided the
tests have been performed with necessary consideration of the geometry and acoustic properties of
the component, and an adequate sensitivity can be employed to enable the acceptance levels of this
document to be applied. The nominal frequency of probes used in this document is between 2 MHz
and 5 MHz, unless attenuation or requirements for higher resolution call for other frequencies. It is
important to consider the use of these acceptance levels in conjunction with frequencies outside this
range carefully.

Zerstörungsfreie Prüfung von Schweißverbindungen - Ultraschallprüfung - Zulässigkeitsgrenzen (ISO 11666:2018)

Dieses Dokument legt zwei Zulässigkeitsgrenzen für die Ultraschallprüfung, bekannt als Zulässigkeits-grenze 2 (AL 2) und Zulässigkeitsgrenze 3 (AL 3), von voll durchgeschweißten Schweißnähten in ferritischen Stählen fest, die den Bewertungsgruppen B und C von ISO 5817:2014 entsprechen. Eine Zulässigkeitsgrenze entsprechend Bewertungsgruppe D von ISO 5817:2014 wurde in dieses Dokument nicht aufgenommen, da eine Ultraschallprüfung für Schweißnähte dieser Bewertungsgruppe im Allgemeinen nicht verlangt wird.
Diese Zulässigkeitsgrenzen sind anwendbar für Prüfungen, die nach ISO 17640 durchgeführt werden.
Dieses Dokument ist anwendbar für die Prüfung von voll Schweißnähten im Wanddickenbereich von 8 mm bis 100 mm. Es kann auch für andere Schweißnahttypen, andere Werkstoffe und Wanddicken angewendet werden, vorausgesetzt, die Prüfungen wurden unter entsprechender Berücksichtigung von Geometrie und akustischen Eigenschaften des Bauteils durchgeführt und es kann eine Prüfempfindlichkeit erreicht werden, mit der die Zulässigkeitsgrenzen dieses Dokuments angewendet werden können. Die Nennfrequenz für die nach diesem Dokument verwendeten Prüfköpfe liegt bei 2 MHz bis 5 MHz, sofern nicht die Schall-schwächung oder Anforderungen an eine erhöhte Auflösung andere Frequenzen erfordern. Die Anwendung dieser Zulässigkeitsgrenzen bei Prüfungen mit Frequenzen außerhalb des genannten Bereichs bedarf zuvor einer kritischen Betrachtung.

Essais non destructifs des assemblages soudés - Contrôle par ultrasons - Niveaux d'acceptation (ISO 11666:2018)

ISO 11666:2018 spécifie deux niveaux d'acceptation, appélés niveau d'acceptation 2 (AL 2) et niveau d'acceptation 3 (AL 3) pour le contrôle par ultrasons de joints en aciers ferritiques soudés à pleine pénétration, qui correspondent aux niveaux de qualité B et C de l'ISO 5817:2014. Il n'a pas été inclus de niveau d'acceptation correspondant au niveau de qualité D de l'ISO 5817:2014 dans le présent document car le contrôle par ultrasons n'est généralement pas demandé pour cette qualité de soudure.
Ces niveaux d'acceptation sont applicables aux contrôles effectués conformément à l'ISO 17640.
ISO 11666:2018 est applicable au contrôle de joints soudés à pleine pénétration en aciers ferritiques, d'épaisseurs allant de 8 mm à 100 mm. Il peut également être utilisé pour d'autres types de soudures, de matériaux et d'épaisseurs, dans la mesure où les contrôles ont été effectués en tenant compte de la géométrie et des caractéristiques acoustiques de l'élément soudé, et où une sensibilité appropriée peut être utilisée pour permettre l'application des niveaux d'acceptation du présent document. La fréquence nominale des palpeurs utilisés dans le présent document est comprise entre 2 MHz et 5 MHz, à moins que l'atténuation ou les exigences d'une meilleure résolution ne justifient une autre fréquence. Il est important d'étudier avec soin l'adoption de ces niveaux d'acceptation en utilisant des fréquences situées en dehors de cette plage.

Neporušitveno preskušanje zvarnih spojev - Ultrazvočno preskušanje - Stopnje sprejemljivosti (ISO 11666:2018)

Ta dokument določa dve stopnji ultrazvočne sprejemljivosti, tj. stopnjo sprejemljivosti 2 (AL 2) in stopnjo sprejemljivosti 3 (AL 3) za zvarne spoje s popolno prevaritvijo pri feritnih jeklih, ki ustrezata ravnem kakovosti B in C po standardu ISO 5817:2014. Raven kakovosti D, ki ustreza standardu ISO 5817:2014, v tem dokumentu ni vključena, saj za to kakovost zvarov ultrazvočno preskušanje običajno ni potrebno.
Te stopnje sprejemljivosti veljajo za preskušanje, izvedeno v skladu s standardom ISO 17640. Ta dokument se uporablja za preskušanje zvarov s popolno prevaritvijo pri feritnih jeklih debeline od 8 mm do 100 mm. Uporablja se lahko tudi za druge vrste zvarov ter druge materiale in debeline, če so bili izvedeni preskusi z ustreznim upoštevanjem geometrijskih in akustičnih lastnosti posamezne komponente ter je mogoče uporabiti zadostno občutljivost, ki omogoča uporabo stopenj sprejemljivosti iz tega dokumenta. Nazivna frekvenca sond, uporabljenih v tem dokumentu, je med 2 MHz
in 5 MHz, razen če so zaradi slabljenja oziroma potreb po višji ločljivosti potrebne drugačne frekvence. Pri uporabi teh stopenj sprejemljivosti v povezavi s frekvencami zunaj tega obsega je potrebna previdnost.

General Information

• Status: Published
• Public Enquiry End Date: 24-May-2017
• Publication Date: 24-Jul-2018
• ICS: 25.160.40 - Welded joints and welds
• Technical Committee: VAR - Welding
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 04-May-2018
• Due Date: 09-Jul-2018
• Completion Date: 25-Jul-2018
• Ref Project: EN ISO 11666:2018 - Non-destructive testing of welds - Ultrasonic testing - Acceptance levels (ISO 11666:2018)

Relations

• Replaces: SIST EN ISO 11666:2011 - Non-destructive testing of welds - Ultrasonic testing - Acceptance levels (ISO 11666:2010)
• Effective Date: 01-Sep-2018

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 11666:2018
01-september-2018
1DGRPHãþD
SIST EN ISO 11666:2011
1HSRUXãLWYHQRSUHVNXãDQMH]YDUQLKVSRMHY8OWUD]YRþQRSUHVNXãDQMH6WRSQMH
VSUHMHPOMLYRVWL,62
Non-destructive testing of welds - Ultrasonic testing - Acceptance levels (ISO
11666:2018)
Zerstörungsfreie Prüfung von Schweißverbindungen - Ultraschallprüfung -
Zulässigkeitsgrenzen (ISO 11666:2018)
Essais non destructifs des assemblages soudés - Contrôle par ultrasons - Niveaux
d'acceptation (ISO 11666:2018)
Ta slovenski standard je istoveten z: EN ISO 11666:2018
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
SIST EN ISO 11666:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 11666:2018

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SIST EN ISO 11666:2018


EN ISO 11666
EUROPEAN STANDARD

NORME EUROPÉENNE

February 2018
EUROPÄISCHE NORM
ICS 25.160.40 Supersedes EN ISO 11666:2010
English Version

Non-destructive testing of welds - Ultrasonic testing -
Acceptance levels (ISO 11666:2018)
Essais non destructifs des assemblages soudés - Zerstörungsfreie Prüfung von Schweißverbindungen -
Contrôle par ultrasons - Niveaux d'acceptation (ISO Ultraschallprüfung - Zulässigkeitsgrenzen (ISO
11666:2018) 11666:2018)
This European Standard was approved by CEN on 21 January 2018.

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, Serbia, 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: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11666:2018 E
worldwide for CEN national Members.

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SIST EN ISO 11666:2018
EN ISO 11666:2018 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 11666:2018
EN ISO 11666:2018 (E)
European foreword
This document (EN ISO 11666:2018) has been prepared by Technical Committee ISO/TC 44 " Welding
and allied processes" in collaboration with Technical Committee CEN/TC 121 “Welding and allied
processes”, the secretariat of which is held by DIN.
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 August 2018, and conflicting national standards shall
be withdrawn at the latest by August 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11666:2010.
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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 11666:2018 has been approved by CEN as EN ISO 11666:2018 without any modification.


3

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SIST EN ISO 11666:2018

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SIST EN ISO 11666:2018
INTERNATIONAL ISO
STANDARD 11666
Second edition
2018-01
Non-destructive testing of welds —
Ultrasonic testing — Acceptance levels
Essais non destructifs des assemblages soudés — Contrôle par
ultrasons — Niveaux d'acceptation
Reference number
ISO 11666:2018(E)
©
ISO 2018

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SIST EN ISO 11666:2018
ISO 11666:2018(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

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SIST EN ISO 11666:2018
ISO 11666:2018(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Determination of discontinuity length . 2
5 Sensitivity setting and levels . 2
6 Acceptance levels . 2
6.1 General . 2
6.2 Indications from longitudinal discontinuities . 3
6.3 Indications from transverse discontinuities . 3
6.4 Grouping of discontinuities . 3
6.5 Length of acceptable discontinuities . 4
Annex A (normative) Levels . 6
Annex B (normative) Fixed-amplitude level technique .17
© ISO 2018 – All rights reserved iii

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SIST EN ISO 11666:2018
ISO 11666:2018(E)

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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 44, Welding and allied processes,
Subcommittee SC 5, Testing and inspection of welds.
This second edition cancels and replaces the first edition (ISO 11666:2010), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— this document has been editorially revised;
— the normative reference to ISO 5817 has been dated;
— Clause 5 and 6.5 have been described in more detail.
Requests for official interpretations of any aspect of this document should be directed to the Secretariat
of ISO/TC 44/SC 5 via your national standards body. A complete listing of these bodies can be found at
www .iso .org.
iv © ISO 2018 – All rights reserved

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SIST EN ISO 11666:2018
INTERNATIONAL STANDARD ISO 11666:2018(E)
Non-destructive testing of welds — Ultrasonic testing —
Acceptance levels
1 Scope
This document specifies two ultrasonic acceptance levels known as acceptance level 2 (AL 2) and
acceptance level 3 (AL 3) for full penetration welded joints in ferritic steels, which correspond to
ISO 5817:2014, quality levels B and C. An acceptance level corresponding to ISO 5817:2014, quality
level D is not included in this document, as ultrasonic testing is generally not requested for this weld
quality.
These acceptance levels are applicable to testing carried out in accordance with ISO 17640.
This document applies to the testing of full penetration ferritic steel welds, with thicknesses from
8 mm to 100 mm. It can also be used for other types of welds, materials and thicknesses, provided the
tests have been performed with necessary consideration of the geometry and acoustic properties of
the component, and an adequate sensitivity can be employed to enable the acceptance levels of this
document to be applied. The nominal frequency of probes used in this document is between 2 MHz
and 5 MHz, unless attenuation or requirements for higher resolution call for other frequencies. It is
important to consider the use of these acceptance levels in conjunction with frequencies outside this
range carefully.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 5577, Non-destructive testing — Ultrasonic testing — Vocabulary
ISO 5817:2014, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections
ISO 17635, Non-destructive testing of welds — General rules for metallic materials
ISO 17640, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and
assessment
ISO 23279, Non-destructive testing of welds — Ultrasonic testing — Characterization of discontinuities
in welds
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5577 appl
...

SLOVENSKI STANDARD
oSIST prEN ISO 11666:2017
01-maj-2017
1HSRUXãLWYHQRSUHVNXãDQMH]YDUQLKVSRMHY8OWUD]YRþQRSUHVNXãDQMH6WRSQMH
VSUHMHPOMLYRVWL,62',6
Non-destructive testing of welds - Ultrasonic testing - Acceptance levels (ISO/DIS
11666:2017)
Zerstörungsfreie Prüfung von Schweißverbindungen - Ultraschallprüfung -
Zulässigkeitsgrenzen (ISO/DIS 11666:2017)
Contrôle non destructif des assemblages soudés - Contrôle par ultrasons - Niveaux
d'acceptation (ISO/DIS 11666:2017)
Ta slovenski standard je istoveten z: prEN ISO 11666
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
oSIST prEN ISO 11666:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 11666:2017

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oSIST prEN ISO 11666:2017
DRAFT INTERNATIONAL STANDARD
ISO/DIS 11666
ISO/TC 44/SC 5 Secretariat: AFNOR
Voting begins on: Voting terminates on:
2017-03-07 2017-05-29
Non-destructive testing of welds — Ultrasonic testing —
Acceptance levels
Contrôle non destructif des assemblages soudés — Contrôle par ultrasons — Niveaux d’acceptation
ICS: 25.160.40
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 11666:2017(E)
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. ISO 2017

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oSIST prEN ISO 11666:2017
ISO/DIS 11666:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 4 ----------------------
oSIST prEN ISO 11666:2017
ISO/DIS 11666:2017(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Measurement of indication length . 1
4 Sensitivity setting and levels . 1
5 Acceptance levels . 2
5.1 General . 2
5.2 Longitudinal indications . 2
5.3 Transverse indications . 3
5.4 Grouping of indications . 3
5.5 Cumulative length of acceptable indications . 4
Annex A (normative) Levels . 5
Annex B (normative) Fixed amplitude level technique.19
© ISO 2017 – All rights reserved iii

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oSIST prEN ISO 11666:2017
ISO/DIS 11666:2017(E)

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 11666 was prepared by the European Committee for Standardization (CEN) Technical Committee
TC 121, Welding, Subcommittee SC 5, Testing of welds, in collaboration with ISO Technical Committee
TC 44, Welding and allied processes, Subcommittee SC 5, Testing and inspection of welds, in accordance
with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
Requests for official interpretations of any aspect of this International Standard should be directed to
the Secretariat of ISO/TC 44/SC 5 via your national standards body. A complete listing of these bodies
can be found at www .iso .org.
iv © ISO 2017 – All rights reserved

---------------------- Page: 6 ----------------------
oSIST prEN ISO 11666:2017
DRAFT INTERNATIONAL STANDARD ISO/DIS 11666:2017(E)
Non-destructive testing of welds — Ultrasonic testing —
Acceptance levels
1 Scope
This International Standard specifies ultrasonic acceptance levels 2 and 3 for full penetration welded
joints in ferritic steels, which correspond to ISO 5817 quality levels B and C. An acceptance level
corresponding to ISO 5817 quality level D is not included in this International Standard as ultrasonic
testing is generally not requested for this weld quality.
These acceptance levels are applicable to testing carried out in accordance with ISO 17640.
This International Standard applies to the examination of full penetration ferritic steel welds, with
thicknesses from 8 mm to 100 mm. It can also be used for other types of welds, materials and thicknesses,
provided the examinations have been performed with necessary consideration of the geometry and
acoustic properties of the component, and an adequate sensitivity can be employed to enable the
acceptance levels of this International Standard to be applied. The nominal frequency of probes used in
this International Standard is between 2 MHz and 5 MHz unless attenuation or requirements for higher
resolution call for other frequencies. The use of these acceptance levels in conjunction with frequencies
outside this range needs to be considered carefully.
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 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections
ISO 17635, Non-destructive testing of welds — General rules for metallic materials
ISO 17640, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and
assessment
ISO 23279, Non-destructive testing of welds — Ultrasonic testing — Characterization of indications in welds
3 Measurement of indication length
The length of an indication shall be determined by measuring the distance along the length over which
the echo amplitude is above the evaluation level, using the fixed amplitude level technique specified in
Annex B.
Alternative techniques for measuring indication length may be used when specified.
4 Sensitivity setting and levels
The sensitivity setting may be performed by one of the following techniques. For sensitivity setting and
the subsequent examinations, the same technique shall be used:
a) technique 1: based on 3 mm diameter side-drilled holes;
b) technique 2: based on distance gain size (DGS) curves for flat-bottom holes (disk-shaped reflectors);
© ISO 2017 – All rights reserved 1

---------------------- Page: 7 ----------------------
oSIST prEN ISO 11666:2017
ISO/DIS 11666:2017(E)

c) technique 3: using a distance-amplitude-corrected (DAC) curve of a rectangular notch of 1 mm
depth and 1 mm width;
d) technique 4: using the tandem technique with reference to a 6 mm diameter flat-bottom hole (disk-
shaped reflector).
Four levels as defined in ISO 17640 are used in this International Standard:
1) reference level;
2) evaluation level;
3) recording levels (for two acceptance levels, reference levels are derived from the relevant
acceptance level minus 4 dB);
4) acceptance levels (for two quality levels).
All levels are linked to the reference reflectors specified in Table A.1.
Annex A specifies levels.
5 Acceptance levels
5.1 General
The relationship between acceptance levels, testing levels and quality levels is given in ISO 17635. See
also Table 1.
Table 1 — Ultrasonic pulse echo technique (UT)
Quality level in accordance with Testing technique and level in Acceptance level in
...