ISO 23279:2007
(Main)Non-destructive testing of welds — Ultrasonic testing — Characterization of indications in welds
Non-destructive testing of welds — Ultrasonic testing — Characterization of indications in welds
ISO 23279:2007 defines a procedure for classifying internal indications as planar or non-planar. This procedure is only suitable for indications located at least 5 mm below the unground surface of the joint.
Contrôle non destructif des assemblages soudés — Contrôle par ultrasons — Caractérisation des indications dans les assemblages soudés
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 23279
First edition
2007-03-15
Non-destructive testing of welds —
Ultrasonic testing — Characterization of
indications in welds
Contrôle non destructif des assemblages soudés — Contrôle par
ultrasons — Caractérisation des indications dans les assemblages
soudés
Reference number
ISO 23279:2007(E)
©
ISO 2007
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ISO 23279:2007(E)
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© ISO 2007
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ISO 23279:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Criteria . 1
3.1 General. 1
3.2 Conventions used. 2
3.3 Location of indications. 2
3.4 Echo height criteria (Stages 1 and 2). 2
3.5 Directional reflectivity criteria (Stage 3). 3
3.6 Echostatic pattern criteria (Stage 4) . 4
3.7 Echodynamic pattern criteria (Stage 5). 4
3.8 Complementary examination. 4
Annex A (normative) Classification of internal indications in welds — Flowchart procedure . 5
Annex B (informative) Examination incidence . 9
Annex C (informative) Basic echodynamic patterns of reflectors . 10
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ISO 23279:2007(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 23279 was prepared by Technical Committee ISO/TC 44, Welding and allied processes, Subcommittee
SC 5, Testing and inspection of welds.
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.
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ISO 23279:2007(E)
Introduction
Classification of indications as planar or non-planar is based on several parameters:
⎯ welding techniques;
⎯ geometrical position of the indication;
⎯ maximum echo height;
⎯ directional reflectivity;
⎯ echostatic pattern (i.e. A-scan);
⎯ echodynamic pattern.
The classification process involves comparing each parameter to all the others in order to arrive at an
accurate conclusion.
The flowchart in Annex A gives the classification of internal weld indications suitable for general applications.
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INTERNATIONAL STANDARD ISO 23279:2007(E)
Non-destructive testing of welds — Ultrasonic testing —
Characterization of indications in welds
1 Scope
This International Standard defines a procedure for classifying internal indications as planar or non-planar.
This procedure is only suitable for indications located at least 5 mm below the unground surface of the joint.
Annex A defines the procedure in the form of a flowchart. Figure 1 illustrates the location of indications.
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.
EN 1712, Non-destructive examination of welds — Ultrasonic examination of welded joints — Acceptance
levels
3 Criteria
3.1 General
The classification is carried out by the successive application of several discriminatory criteria, i.e.
⎯ echo amplitude;
⎯ directional reflectivity;
⎯ echostatic pattern (A-scan);
⎯ echodynamic pattern.
The classification is carried out in accordance with EN 1712.
The flowchart procedure is stopped as soon as one of the above criteria is fulfilled.
The probes used for the classification are, as a general rule, the same as those specified for the detection.
The flowchart procedure standardizes a quality control system of classification. Several levels are defined in
decibels (dB) by a comparison with the distance amplitude curve (DAC) or by a comparison between the
maximum echo heights from the discontinuity when tested at different angles of incidence.
Proposed dB levels for the different stages in the flowchart procedure are given in Table 1.
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ISO 23279:2007(E)
Table 1 — Proposed dB levels for the different stages in the flowchart procedure
Reflectivity level S1 S2 S3 S4
a b
Decibel DAC – 10 dB DAC + 6 dB DAC – 6 dB 9 dB /15 dB
a
Shear waves.
b
Between reflections obtained with a shear and a longitudinal wave.
The flowchart procedure calls for five stages, each having a precise aim:
⎯ Stage 1: to avoid the classification of indications with very low echo amplitudes;
⎯ Stage 2: to classify all indications with high echo amplitude as planar;
⎯ Stage 3: primarily to classify lack of fusion;
⎯ Stage 4: primarily to classify inclusions;
⎯ Stage 5: primarily to classify cracks.
NOTE The “hybrid” indications resulting from the association of an inclusion and a lack of fusion are classified as
planar by the flowchart procedure. An example of this type of flaw is given in Figure A.3.
3.2 Conventions used
The reference echoes shall be obtained on 3 mm side drilled holes.
By convention,
⎯ a negative level value means that the indication has a lower echo amplitude than the reference;
⎯ a positive level value means that the indication has a higher echo amplitude than the reference.
3.3 Location of indications
Figure 1 illustrates the location of indications.
Dimensions in millimetres
Key
A ground weld
Figure 1 — Location of indications
3.4 Echo height criteria (Stages 1 and 2)
3.4.1 Low amplitudes (Stage 1)
It is accepted that an indication with a lower echo amplitude than level S1 (DAC – 10 dB) is not significant.
For special applications, this S1 value should be lowered if agreed between the contracting parties.
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ISO 23279:2007(E)
3.4.2 High amplitudes (Stage 2)
It is assumed that an echo height that is at least equal to the level S2 (DAC + 6 dB) comes from a planar
indication.
3.5 Directional reflectivity criteria (Stage 3)
This stage of the flowchart procedure shall be applicable either to all indications or, if agreed between the
contracting parties, only to those indications exceeding a specified length. For the range of thicknesses
8 mm u t u 15 mm, this length is t, and for thicknesses over 15 mm, this length is t/2 or 20 mm, whichever is
the larger. For indications not exceeding the specified length, proceed to Stage 4.
For the criteria below, the angle of incidence of examination which gives the highest echo amplitude relative to
a DAC curve, H , is taken as referen
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