SIST EN ISO 17640:2018

SLOVENSKI STANDARD
oSIST prEN ISO 17640:2016
01-junij-2016
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Non-destructive testing of welds - Ultrasonic testing - Techniques, testing levels, and
assessment (ISO/DIS 17640:2016)
Zerstörungsfreie Prüfung von Schweißverbindungen - Ultraschallprüfung - Techniken,
Prüfklassen und Bewertung (ISO/DIS 17640:2016)
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Ta slovenski standard je istoveten z: prEN ISO 17640
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
oSIST prEN ISO 17640:2016 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 17640:2016

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oSIST prEN ISO 17640:2016
DRAFT INTERNATIONAL STANDARD
ISO/DIS 17640
ISO/TC 44/SC 5 Secretariat: AFNOR
Voting begins on: Voting terminates on:
2016-03-17 2016-06-17
Non-destructive testing of welds — Ultrasonic testing —
Techniques, testing levels, and assessment
Contrôle non destructif des assemblages soudés — Contrôle par ultrasons — Techniques, niveaux d’essai
et évaluation
ICS: 25.160.40
ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for
Standardization (ISO), and processed under the ISO lead mode of collaboration
as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member
bodies for a parallel three month enquiry.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
To expedite distribution, this document is circulated as received from the
IN ADDITION TO THEIR EVALUATION AS
committee secretariat. ISO Central Secretariat work of editing and text
BEING ACCEPTABLE FOR INDUSTRIAL,
composition will be undertaken at publication stage.
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 17640:2016(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 2016

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oSIST prEN ISO 17640:2016
ISO/DIS 17640:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, 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
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Tel. +41 22 749 01 11
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copyright@iso.org
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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
Contents Page
Foreword .iv
1 Scope.5
2 Normative references .5
3 Symbols and definitions .6
4 Principle .7
5 Information required prior to testing.7
5.1 Items to be specified .7
5.2 Specific information required before testing .8
5.3 Written test procedure .9
6 Requirements for personnel and equipment .9
6.1 Personnel qualifications .9
6.2 Equipment .9
6.3 Probe parameters.9
7 Testing volume . 11
8 Preparation of scanning surfaces. 11
9 Parent metal testing . 11
10 Range and sensitivity setting . 13
10.1 General . 13
10.2 Reference for sensitivity setting. 13
10.3 Evaluation levels . 15
10.4 Transfer correction . 15
10.5 Signal to noise ratio . 15
11 Testing levels . 15
12 Testing techniques. 16
12.1 General . 16
12.2 Manual scan path . 16
12.3 Testing for imperfections perpendicular to the testing surface. 16
12.4 Location of indications . 16
12.5 Evaluation of indications . 17
13 Test report . 18
Annex A (normative) Testing levels for various types of welded joints . 21

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oSIST prEN ISO 17640:2016
ISO 17640:2016(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 17640 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).
This second edition cancels and replaces the first edition (ISO 17640:2005), which has been technically
revised.
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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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and
assessment
1 Scope
This International Standard specifies techniques for the manual ultrasonic testing of fusion-welded joints in metallic materials of thickness greater than or
equal to 8 mm which exhibit low ultrasonic attenuation (especially that due to scatter) at object temperatures from 0 °C to 60 °C. It is primarily intended for
use on full penetration welded joints where both the welded and parent material are ferritic.
Where material-dependent ultrasonic values are specified in this International Standard, they are based on steels having an ultrasonic sound velocity of
(5 920  50) m/s for longitudinal waves and (3 255  30) m/s for transverse waves.
This International Standard specifies four testing levels, each corresponding to a different probability of detection of imperfections. Guidance on the selection
of testing levels A, B, and C is given in Annex A.
This International Standard specifies that the requirements of testing level D, which is intended for special applications, be in accordance with general
requirements. Testing level D can only be used when defined by specification. This includes tests of metals other than ferritic steel, tests on partial
penetration welds, tests with automated equipment, and tests at object temperatures outside the range 0 °C to 60 °C.
This International Standard can be used for the assessment of indications, for acceptance purposes, by either of the following techniques:
a) evaluation based primarily on length and echo amplitude of the indication;
b) evaluation based on characterization and sizing of the indication by probe movement techniques.
The techniques used shall be specified.
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
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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
ISO 9712, Non-destructive testing — Qualification and certification of personnel
ISO 11666:2010, Non-destructive testing of welds — Ultrasonic testing of welded joints — Acceptance levels
ISO 16810, Non-destructive testing - Ultrasonic testing - General principles
ISO 16811, Non-destructive testing - Ultrasonic testing - Sensitivity and range setting
ISO 16826, Non-destructive testing - Ultrasonic testing - Examination for discontinuities perpendicular to the surface
ISO 17635, Non-destructive testing of welds — General rules for metallic materials
ISO 23279, Non-destructive testing of welds — Ultrasonic testing — Characterization of discontinuities in welds
EN 1330-4, Non-destructive testing — Terminology — Part 4: Terms used in ultrasonic testing
EN 12668 (all parts), Non-destructive testing — Characterization and verification of ultrasonic examination equipment
3 Symbols and definitions
3.1 For the purposes of this International Standard, the definitions given in EN 1330-4 and ISO 17635 apply.
3.2 For symbols, their definitions, and units, see Table 1.
Indications shall be considered to be either longitudinal or transverse, depending on the direction of their major dimension with respect to the weld axis, x, in
accordance with Figure 2.
Table 1 — Symbols, their definitions, and units
Symbol Definition Unit
D diameter of the disk-shaped reflector mm
DSR
h extension of the indication in depth direction mm
l length of the indication mm
l projected length of the indication in the x-direction mm
x
l projected length of the indication in the y-direction mm
y
p full skip distance mm
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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
t thickness of parent material * mm
x position of the discontinuity in the longitudinal direction mm
y position of the discontinuity in the transverse direction mm
z position of the discontinuity in depth mm
 * If the joined parts have no equal thickness, the smallest thickness shall be considered
4 Principle
The purpose of this International Standard is to describe general techniques of ultrasonic weld testing, using standard criteria, for the most commonly used
welded joints at object temperatures in the range 0 °C to 60 °C. The specific requirements of this International Standard cover the equipment, preparation,
performance of the testing, and reporting. The parameters specified, in particular those for the probes, are compatible with the requirements of ISO 11666
and ISO 23279.


5 Information required prior to testing
5.1 Items to be specified
These include:
a) method for setting the reference level;
b) method to be used for evaluation of indications;
c) acceptance levels;
d) testing level;
e) manufacturing and operation stage(s) at which the testing is to be carried out;
f) qualification of personnel;
g) extent of the testing for transverse indications;
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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
h) requirements for additional tandem testing (see ISO 16826);
i) parent metal testing prior to and/or after welding;
j) whether or not a written testing procedure is required;
k) requirements for written testing procedures.
5.2 Specific information required before testing
Before any testing of a welded joint can begin, the operator shall have access to the following essential information:
a) written testing procedure, if required (see 5.3);
b) type(s) of parent material and product form (i.e. cast, forged, rolled);
c) manufacturing or operation stage at which testing is to be made, including heat treatment, if any;
d) time and extent of any post-weld heat treatment;
e) joint preparation and dimensions;
f) requirements for surface conditions;
g) welding procedure or relevant information on the welding process;
h) reporting requirements;
i) acceptance levels;
j) extent of testing, including requirements for transverse indications, if relevant;
k) testing level;
l) personnel qualification level;
m) procedures for corrective actions when unacceptable indications are revealed.
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oSIST prEN ISO 17640:2016
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5.3 Written test procedure
The definitions and requirements in this International Standard normally satisfy the need for a written test procedure.
Where this is not the case, or where the techniques described in this International Standard are not applicable to the weld joint to be examined, additional
written test procedures shall be used, if required by specification.
6 Requirements for personnel and equipment
6.1 Personnel qualifications
Personnel performing testing in accordance with this International Standard shall be qualified to an appropriate level in ultrasonic testing in accordance with
ISO 9712 or equivalent in the relevant industrial sector.
In addition to a general knowledge of ultrasonic weld testing, personnel shall also be familiar with testing problems specifically associated with the type of
welded joints to be examined.
6.2 Equipment
Any equipment used for testing in conjunction with this International Standard shall comply with the requirements of EN 12668 (all parts).
6.3 Probe parameters
6.3.1 Test frequency
The frequency shall be within the range 1,5 MHz to 5 MHz, and shall be selected to comply with the specified acceptance levels.
For the initial testing, the frequency shall be as low as possible, within the above range, when the evaluation is carried out according to acceptance levels
based on length and amplitude, e.g. ISO 11666. Higher frequencies may be used to improve range resolution if this is necessary when using standards for
acceptance levels based on characterization of discontinuities, e.g. ISO 23279.
Frequencies of approximately 1 MHz may be used for testing at long sound paths where the material shows above average attenuation.
6.3.2 Angles of incidence
When testing is carried out with transverse waves and techniques that require the ultrasonic beam to be reflected from an opposite surface, care shall be
taken to ensure that the angle between the beam and the normal to the opposite reflecting surface is between 35° and 70°. Where more than one probe
angle is used, at least one of the angle probes used shall conform with this requirement. One of the probe angles used shall ensure that the weld fusion faces
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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
are examined at, or as near as possible to, normal incidence. When the use of two or more probe angles is specified, the difference between the nominal
beam angles shall be 10° or greater.
Angles of incidence at the probe and opposite reflecting surface, when curved, may be determined by drawing a sectional view of the weld or in accordance
with the techniques given in ISO 16811. Where angles of incidence cannot be determined as specified by this International Standard, the testing report shall
contain a comprehensive description of the scans used and the extent of any incomplete coverage caused, together with an explanation of the difficulties
encountered.
6.3.3 Element size
The element size shall be chosen according to the ultrasonic path to be used and the frequency.
The smaller the element, the smaller the length and width of the near field, and the larger the beam spread in the far field at a given frequency.
Small probes having 6 mm to 12 mm diameter elements (or rectangular elements of equivalent area) are therefore most useful when working at short beam
path ranges. For longer ranges, i.e. greater than 100 mm for single normal beam probes and greater than 200 mm for angle beam probes, an element size of
12 mm to 24 mm is more suitable.
6.3.4 Adaptation of probes to curved scanning surfaces
The gap, g, between test surface and bottom of the probe shoe shall not be greater than 0,5 mm.
For cylindrical or spherical surfaces, this requirement can be checked with Equation (1):
2
g = a /4D (1)
where
a is the dimension, in millimetres, of the probe shoe in the direction of testing;
D is the diameter, in millimetres, of the component.
If a value for g larger than 0,5 mm results from the equation, the probe shoe shall be adapted to the surface and the sensitivity and range shall be set
accordingly.
6.3.5 Coupling media
The coupling media shall be in accordance with ISO 16810. The coupling medium used for range and sensitivity setting and for the test shall be the same.
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7 Testing volume
The testing volume (see Figure 1) is defined as the zone which includes weld and parent material for at least 10 mm on each side of the weld, or the width of
the heat-affected zone, whichever is greater.
In all cases, scanning shall cover the whole testing volume. If individual sections of this volume cannot be covered in at least one scanning direction, or if the
angles of incidence with the opposite surface do not meet the requirements of 6.3.2, alternative or supplementary ultrasonic techniques or other non-
destructive techniques shall be agreed upon. This may, in some cases, require removal of the weld reinforcement.
Supplementary techniques may require testing using dual-element angle-beam probes, creeping wave probes, further ultrasonic techniques or any other
suitable method, e.g. liquid penetrant, magnetic particle, radiographic testing. In selecting alternative or supplementary techniques, due consideration should
be given to the type of weld and probable orientation of any imperfections to be detected.
8 Preparation of scanning surfaces
Scanning surfaces shall be wide enough to permit the testing volume (see Figure 1) to be fully covered. Alternatively, the width of the scanning surfaces may
be smaller if equivalent coverage of the testing volume can be achieved by scanning from both the upper and the lower surface of the joint.
Scanning surfaces shall be even and free from foreign matter likely to interfere with probe coupling (e.g. rust, loose scale, weld spatter, notches, grooves).
Waviness of the test surface shall not result in a gap between the probe and test surfaces greater than 0,5 mm. These requirements shall be ensured by
dressing if necessary. Local variations in surface contour, e.g. along the edge of the weld, which result in a gap beneath the probe of up to 1 mm, can only be
permitted if at least one additional probe angle is employed from the affected side at the weld. This additional scanning is necessary to compensate for the
reduced weld coverage that will occur with a gap of this dimension.
Scanning surfaces and surfaces from which the sound beam is reflected shall allow undisturbed coupling and reflection.
9 Parent metal testing
The parent metal, in the scanning zone area (see Figure 1), shall be examined with straight-beam probes prior to or after welding, unless it can be
demonstrated (e.g. by previous testing during the fabrication process) that the angle-beam testing of the weld is not influenced by the presence of the
imperfections or high attenuation.
Where imperfections are found, their influence on the proposed angle-beam testing shall be assessed and, if necessary, the techniques adjusted
correspondingly. When satisfactory coverage by ultrasonic testing is seriously affected, other inspection techniques (e.g. radiography) shall be considered.
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oSIST prEN ISO 17640:2016
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Dimensions in millimetres

Key
1 position 1
2 position 2
3 position 3
a w idth of testing volume
b scanning zone w idth
Figure 1 — Example of testing volume to be covered when scanning for longitudinal indications
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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
10 Range and sensitivity setting
10.1 General
Setting of range and sensitivity shall be carried out prior to each testing in accordance with this International Standard and ISO 16811, taking the influence of
temperature into account. The temperature difference during range and sensitivity setting and during the test shall be within 15 °C.
Checks to confirm these settings shall be performed at least every 4 h and on completion of the testing. Checks shall also be carried out whenever a system
parameter is changed or changes in the equivalent settings are suspected.
If deviations greater than 2 dB, resp. 1 % of range, are found during these checks, the corrections given in Table 2 shall be carried out.
Table 2 — Sensitivity and range corrections
Sensitivity
1 Deviations ≤ 4 dB Setting shall be corrected before the testing is continued.
2 Setting shall be corrected and all testing carried out w ith
Reduction of the sensitivity  4 dB
the equipment over the previous period shall be
repeated.
3 Setting shall be corrected and all recorded indications
Increase in sensitivity  4 dB
shall be re-examined.
Range
1 Setting shall be corrected before testing is continued.
Deviations ≤ 2 % of the range
2 Setting shall be corrected and testing carried out w ith the
Deviations  2 % of the range
equipment over the previous period shall be repeated.

10.2 Reference for sensitivity setting
One of the following techniques for setting the reference shall be used.
The use of these techniques may not result in equal test results.
Different testing results may occur by usage of different techniques for sensitivity setting.
a) Technique 1: the reference is a distance-amplitude curve (DAC) for side-drilled holes of diameter 3 mm.
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oSIST prEN ISO 17640:2016
ISO 17640:2016(E)
b) Technique 2: the references for transverse and longitudinal waves using the distance gain size (DGS) system based on the diameter of the disk-shaped
reflector (DSR) are given in Tables 3 and 4 respectively.
c) Technique 3: the reference notch shall be 1 mm wide, rectangular, with a depth of 1 mm. This technique applies only for the thickness range 8 mm
≤ t  15 mm and for beam angles ≥ 70°.
d) Technique 4: for the tandem technique, the reference is a flat-bottomed hole of 6 mm diameter (for all thicknesses), perpendicular to the scanning
surface. This technique is applicable only for beam angle 45° and thickness t ≥ 40 mm.
The length of the side-drilled holes and notches shall be greater than the width of the sound beam measured at 20 dB.


Table 3 — Reference levels for acceptance levels 2 and 3 for technique 2 using angle-beam scanning with transverse waves
Thickness of parent material, t
Nominal probe
frequency
8 mm t  15 mm 15 mm t  40 mm 40 mm t  100 mm
MHz AL 2 AL 3 AL 2 AL 3 AL 2 AL 3
1,5 to 2,5 — — D = 2,5 mm D = 2,5 mm D = 3,0 mm D = 3,0 mm
DSR DSR DSR DSR
3,0 to 5,0 D = 1,5 mm D = 1,5 mm D = 2,0 mm D = 2,0 mm D = 3,0 mm D = 3,0 mm
DSR DSR DSR DSR DSR DSR
D is the diameter of the disk-shaped reflector.
DSR

Table 4 — Reference levels for acceptance levels 2 and 3 for technique 2 using straight-beam scanning with longitudinal waves
Thickness of parent material, t
Nominal probe
frequency
8 mm t  15 mm 15 mm t  40 mm 40 mm t  100 mm
MHz AL 2 AL 3 AL 2 AL 3 AL 2 AL 3
1,5 to 2,5 — — D = 2,5 mm D = 2,5 mm D = 3,0 mm D = 3,0 mm
DSR DSR DSR DSR
3,0 to 5,0 D = 2,0 mm D = 2,0 mm D = 2,0 mm D = 2,0 mm D = 3,0 mm D = 3,0 mm
DSR DSR DSR DSR DSR DSR
D is the diameter of the disk-shaped reflector.
DSR

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10.3 Evaluation levels
All indications equal to or exceeding the following levels shall be evaluated.
The evaluation levels for techniques 1 to 4 are given in ISO 11666:20xx, Table A.1.
10.4 Transfer correction
When separate blocks are used for establishing reference levels, a measurement shall be made of the transfer differences, bet ween test object and block, at
a representative number of locations. Suitable techniques are described in ISO 16811.
If the differences are less than 2 dB, correction is not required.
If the differences are greater than 2 dB but smaller than 12 dB, they shall be compensated for.
If transfer losses exceed 12 dB, the reason shall be considered and further preparation of the scanning surfaces shall be carried out, if applicable.
When there are no apparent reasons for high correction values, the attenuation, at various locations on the test object, shall be measured and, where it is
found to vary significantly, corrective actions shall be considered.
10.5 Signal to noise ratio
During testing of the weld, the noise level, excluding spurious surface indications, shall remain at least 12 dB below the evaluation level. This requirement
may be relaxed subject to specification.
11 Testing levels
Quality requirements for welded joints are mainly associated with the material, welding process and service conditions. To accommodate all of these
requirements, this International Standard specifies four testing levels (A, B, C, and D).
From testing level A to testing level C, an increasing probability of detection is achieved by an increasing testing coverage, e.g.
...