EN ISO 10863:2020

SLOVENSKI STANDARD
01-september-2020
Nadomešča:
SIST EN ISO 10863:2011
Neporušitveno preskušanje zvarov - Ultrazvočno preskušanje - Uporaba tehnike
TOFD (ISO 10863:2020)
Non-destructive testing of welds - Ultrasonic testing - Use of time-of-flight diffraction
technique (TOFD) (ISO 10863:2020)
Zerstörungsfreie Prüfung von Schweißverbindungen - Ultraschallprüfung - Anwendung
der Beugungslaufzeittechnik (TOFD) (ISO 10863:2020)
Essais non destructifs des assemblages soudés - Contrôle par ultrasons - Utilisation de
la technique de diffraction des temps de vol (TOFD) (ISO 10863:2020)
Ta slovenski standard je istoveten z: EN ISO 10863:2020
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 10863
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2020
EUROPÄISCHE NORM
ICS 25.160.40 Supersedes EN ISO 10863:2011
English Version
Non-destructive testing of welds - Ultrasonic testing - Use
of time-of-flight diffraction technique (TOFD) (ISO
10863:2020)
Essais non destructifs des assemblages soudés - Zerstörungsfreie Prüfung von Schweißverbindungen -
Contrôle par ultrasons - Utilisation de la technique de Ultraschallprüfung - Anwendung der
diffraction des temps de vol (TOFD) (ISO 10863:2020) Beugungslaufzeittechnik (TOFD) (ISO 10863:2020)
This European Standard was approved by CEN on 19 May 2020.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, 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
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10863:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 10863:2020) 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 December 2020, and conflicting national standards
shall be withdrawn at the latest by December 2020.
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 10863:2011.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 10863:2020 has been approved by CEN as EN ISO 10863:2020 without any modification.

INTERNATIONAL ISO
STANDARD 10863
Second edition
2020-05
Non-destructive testing of welds —
Ultrasonic testing — Use of time-of-
flight diffraction technique (TOFD)
Essais non destructifs des assemblages soudés — Contrôle par ultrasons
— Utilisation de la technique de diffraction des temps de vol (TOFD)
Reference number
ISO 10863:2020(E)
©
ISO 2020
ISO 10863:2020(E)
© ISO 2020
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
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 10863:2020(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 General remarks on the capabilities of the technique . 2
5 Testing levels . 3
6 Information required prior to testing . 4
6.1 Items to be defined by specification . 4
6.2 Specific information required by the operator before testing . 4
6.3 Written test instruction or procedure . 4
7 Requirements for test personnel and test equipment . 5
7.1 Personnel qualifications . 5
7.2 Test equipment . 5
7.2.1 Ultrasonic instrument . 5
7.2.2 Ultrasonic probes . 5
7.2.3 Scanning mechanisms . 5
8 Preparation for testing . 5
8.1 Volume to be tested . 5
8.2 Setup of probes . 6
8.3 Scan increment setting . 7
8.4 Geometry considerations . 7
8.5 Preparation of scanning surfaces . 7
8.6 Temperature . 8
8.7 Couplant . 8
8.8 Provision of datum points . 8
9 Testing of base material . 8
10 Range and sensitivity settings . 8
10.1 Settings . 8
10.1.1 General. 8
10.1.2 Time window . 8
10.1.3 Time-to-depth conversion . 8
10.1.4 Sensitivity settings . 9
10.2 Checking of the settings . 9
10.3 Reference blocks . 9
10.3.1 General. 9
10.3.2 Material . 9
10.3.3 Dimensions and shape .10
10.3.4 Reference reflectors .10
11 Weld testing .10
12 Interpretation and analysis of TOFD images .11
12.1 General .11
12.2 Assessing the quality of the TOFD image .11
12.3 Identification of relevant TOFD indications .11
12.4 Classification of relevant TOFD indications .11
12.4.1 General.11
12.4.2 TOFD indications from surface-breaking discontinuities .12
12.4.3 TOFD indications from embedded discontinuities .12
12.4.4 Unclassified TOFD indications .13
12.5 Determination of location .13
12.6 Definition and determination of length and height .13
ISO 10863:2020(E)
12.6.1 General.13
12.6.2 Determination of length .14
12.6.3 Determination of height .16
12.7 Evaluation against acceptance criteria .17
13 Test report .17
Annex A (informative) Reference blocks .19
Annex B (informative) Examples of TOFD scans .24
Bibliography .37
iv © ISO 2020 – All rights reserved

ISO 10863:2020(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 of 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 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 10863:2011), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the whole document has been updated to the state of the art; ISO 22232 series has been taken into
account;
— Clause 3 has been updated;
— Figure 1 to Figure 6 have been added;
— Figure B.1 to Figure B.18 have been updated.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
Official interpretations of ISO/TC 44 documents, where they exist, are available from this page: https://
committee .iso .org/ sites/ tc44/ home/ interpretation .html.
INTERNATIONAL STANDARD ISO 10863:2020(E)
Non-destructive testing of welds — Ultrasonic testing —
Use of time-of-flight diffraction technique (TOFD)
1 Scope
This document specifies the application of the time-of-flight diffraction (TOFD) technique to the
semi- or fully automated ultrasonic testing of fusion-welded joints in metallic materials of minimum
thickness 6 mm.
It applies to full penetration welded joints of simple geometry in plates, pipes, and vessels, where both
the weld and the parent material are low-alloyed carbon steel. Where specified and appropriate, TOFD
can also be used on other types of materials that exhibit low ultrasonic attenuation (especially that due
to scatter).
Where material-dependent ultrasonic parameters are specified in this document, they are based on
steels having a sound velocity of (5 920 ± 50) m/s for longitudinal waves and (3 255 ± 30) m/s for
transverse waves. It is necessary to take this fact into account when testing materials with a different
velocity.
This document makes reference to ISO 16828 and provides guidance on the specific capabilities and
limitations of TOFD for the detection, location, sizing and characterization of discontinuities in fusion-
welded joints. TOFD can be used as a stand-alone method or in combination with other non-destructive
testing (NDT) methods or techniques, for manufacturing inspection, and for in-service inspection.
This document specifies four testing levels (A, B, C, D) in accordance with ISO 17635 and corresponding
to an increasing level of testing reliability. Guidance on the selection of testing levels is provided.
This document permits assessment of TOFD indications for acceptance purposes. This assessment is
based on the evaluation of transmitted, reflected and diffracted ultrasonic signals within a generated
TOFD image.
This document does not include acceptance levels for discontinuities.
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 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 16828, Non-destructive testing — Ultrasonic testing — Time-of-flight diffraction technique as a
method for detection and sizing of discontinuities
ISO 17640, Non-destructive testing of welds — Ultrasonic testing — Techniques, testing levels, and
assessment
1)
ISO 22232-1 , Non-destructive testing — Characterization and verification of ultrasonic test equipment —
Part 1: Instruments
1) Under preparation. (Preparation at the time of publication: ISO/FDIS 22232-1.)
ISO 10863:2020(E)
2)
ISO 22232-2 , Non-destructive testing — Characterization and verification of ultrasonic test equipment —
Part 2: Probes
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5577 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
time-of-flight diffraction image
TOFD image
two-dimensional image, constructed by collecting adjacent A-scans while moving the time-of-flight
diffraction setup (3.3)
Note 1 to entry: The signal amplitude of the A-scans is typically represented by grey-scale values.
3.2
time-of-flight diffraction indication
TOFD indication
pattern or disturbance in the time-of-flight diffraction image (3.1) which can need further evaluation
3.3
time-of-flight diffraction setup
TOFD setup
probe arrangement defined by probe characteristics (e.g. frequency, probe element size, beam angle,
wave mode) and probe centre separation (3.6)
3.4
beam intersection point
point of intersection of the two main beam axes
3.5
lateral wave
longitudinal wave traveling the shortest path from transmitter probe to receiver probe
3.6
probe centre separation
PCS
distance between the index points of the two probes
Note 1 to entry: The PCS for two probes located on a curved surface is the straight-line, geometric separation
between the two probe index points and not the distance measured along the surface.
3.7
offset scan
scan parallel to the weld axis, where the beam intersection point (3.4) is not on the centreline of the weld
4 General remarks on the capabilities of the technique
General principles of the TOFD technique are described in ISO 16828. For the testing of fusion-welded
joints, some specific capabilities and limitations of the technique shall be considered.
2) Under preparation. (Preparation at the time of publication: ISO/DIS 22232-2.)
2 © ISO 2020 – All rights reserved

ISO 10863:2020(E)
The TOFD technique is an ultrasonic image-generating technique, which offers the capability of
detection, location, and sizing. To a certain extent, characterization of discontinuities in the weld
material as well as in the adjacent parent material is also possible.
Compared with purely reflection-based techniques, the TOFD technique, which is based on diffraction
as well as reflection, is less sensitive to the orientation of the discontinuity. Discontinuities oriented
perpendicular to the surface, and at intermediate angles of tilt, are detectable as well as discontinuities
in the weld fusion faces.
In certain circumstances (e.g. thickness, weld preparation, scope of testing) more than one single TOFD
setup is required.
A typical TOFD image is linear in time (vertical axis) and probe movement (horizontal axis). Because of
the V-configuration of the ultrasound paths, the location of a possible discontinuity is then non-linear.
TOFD testing shall be carried out in a correct and consistent way, such that valid images are generated
which can be evaluated correctly, e.g. coupling losses and data acquisition errors shall be avoided,
see 12.2.
The interpretation of TOFD images requires skilled and experienced operators. Some typical TOFD
images of discontinuities in fusion-welded joints are provided in Annex B.
There is a reduced capability for the detection of discontinuities close to or connected with the scanning
surface or with the opposite surface. This shall be considered especially for crack-sensitive steels or
at in-service inspections. In cases where full coverage of these zones is required, additional measures
shall be taken, e.g. TOFD can be accompanied by other NDT methods or techniques.
Diffracted signals from weld discontinuities can have small amplitude responses. The grain scatter
effect from coarse-grained material can hinder the detection and evaluation of such responses. This
shall be taken into account whenever testing such material.
5 Testing levels
This document specifies four testing levels (A, B, C and D, see Table 1). From testing level A to testing
level C an increasing reliability is achieved.
Table 1 — Testing levels
Reference block for Reference block for
Written
Testing level TOFD setup setup verification sensitivity settings Offset scan
test procedure
(see 8.2) (see 10.1.4)
A As in Table 2 No No No This document
B As in Table 2 No Yes No This document
C As in Table 2 Yes Yes a Yes
As defined by
D Yes Yes a Yes
specification
a
The necessity, number and position of offset scans shall be determined.
If the specified acceptance level requires detection of a certain discontinuity size at both surfaces or
one surface of the weld (see Clause 4), this can necessitate the use of techniques or methods outside the
scope of this document.
For manufacturing inspections (see also ISO 17635), all testing levels are applicable. Level A is only
applicable for wall thicknesses up to 50 mm. For in-service inspections, only testing level D shall be
applied.
ISO 10863:2020(E)
6 Information required prior to testing
6.1 Items to be defined by specification
Information on the following items is required:
a) purpose and extent of TOFD testing (see Clause 5 and Clause 8);
b) testing levels (see Clause 5), e.g.:
1) whether a written test procedure is required,
2) whether reference blocks are required;
c) specification of reference blocks, if required (see 10.3);
d) manufacturing or operation stage at which the testing is to be carried out;
e) requirements for: temperature, access and surface conditions (see Clause 8);
f) reporting requirements (see Clause 13);
g) acceptance criteria;
h) personnel qualifications (see 7.1).
6.2 Specific information required by the operator before testing
Before any testing of a welded joint can begin, the operator shall have access to all the information as
specified in 6.1 together with the following additional information:
a) written test instruction or procedure (see 6.3), if required;
b) type(s) of parent material and product form (i.e. cast, forged, rolled);
c) joint preparation and dimensions;
d) welding procedure or relevant information on the welding process;
e) time of testing relative to any post-weld heat treatment;
f) result of any parent metal testing carried out prior to and/or after welding;
g) discontinuity type and morphology to be detected.
6.3 Written test instruction or procedure
For testing levels A and B, this document satisfies the need for a written test procedure.
For testing levels C and D, or where the techniques described in this document are not applicable to the
welded joint to be tested, a specific written test procedure shall be used.
When data collection is performed by personnel qualified to Level 1 according to ISO 9712, a written test
instruction shall be prepared. The written test instruction shall contain as a minimum the information
listed in Clause 13.
4 © ISO 2020 – All rights reserved

ISO 10863:2020(E)
7 Requirements for test personnel and test equipment
7.1 Personnel qualifications
In addition to a general knowledge of ultrasonic weld testing, all personnel shall be competent in
the TOFD technique. Documented evidence of their competence (level of training and experience) is
required.
Preparation of written test instructions, final off-line analysis of data, and acceptance of the report shall
be performed by personnel qualified as a minimum to Level 2 in accordance with ISO 9712 or equivalent
in ultrasonic testing in the relevant industrial sector. In accordance with a written instruction and
under the supervision of Level 2 or Level 3 personnel, equipment setup, data acquisition, data storage,
and report preparation can be performed by personnel qualified to a minimum of Level 1 in accordance
with ISO 9712 or equivalent in ultrasonic testing in the relevant industrial sector.
For data acquisition, the Level 1 personnel may be supported by an assistant technician.
In cases where the above minimum qualifications are not considered adequate, job-specific training
shall be carried out.
7.2 Test equipment
7.2.1 Ultrasonic instrument
The ultrasonic instrument used for the TOFD technique shall comply with the requirements of
ISO 22232-1, where applicable.
The TOFD software shall not mask any problems such as loss of coupling, missing scan lines,
synchronization errors or electronic noise.
In addition, the requirements of ISO 16828 shall apply, taking into account the following:
a) the instrument shall be able to select an appropriate portion of the time base within which A-scans
are digitized;
b) it is recommended that a sampling rate of the A-scan of at least 6 times the nominal probe frequency
be used.
7.2.2 Ultrasonic probes
Probes used for the TOFD technique on welds shall comply with ISO 22232-2 and ISO 16828.
Adaptation of probes to curved scanning surfaces shall comply with ISO 17640.
A recommendation for the selection of probes is given in Table 2.
7.2.3 Scanning mechanisms
The requirements of ISO 16828 shall apply. To achieve consistency of the images (collected data),
guiding mechanisms may be used.
8 Preparation for testing
8.1 Volume to be tested
Testing shall be performed in accordance with ISO 16828. The purpose of the testing shall be defined by
specification. Based on this, the volume to be tested shall be determined.
ISO 10863:2020(E)
The volume to be tested is located between the probes. For testing levels A and B, the probes shall be
placed symmetrically about the weld centreline. For testing levels C and D, additional offset scans may
be required.
For manufacturing inspection, the volume to be tested 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, the whole volume to be tested shall be covered.
Normally these tests are performed in accordance with recognized standards applying acceptance
levels for quality assurance. If fitness-for-purpose methods are applied, then corresponding acceptance
criteria shall be specified.
For in-service inspections, the volume to be tested may be targeted to specific areas of interest, e.g. the
inner third of the weld body. The acceptance criteria and minimum discontinuity size to be detected in
the area of interest shall be specified.
8.2 Setup of probes
The probes shall be set up to ensure adequate coverage and optimum conditions for the initiation
and detection of diffracted signals in the area of interest. For butt welds of simple geometry and with
narrow weld crowns at the opposite surface, the testing shall be performed in one or more setups
(scans) dependent on the wall thickness (see Table 2). For other configurations, e.g. X-shaped welds,
different base metal thickness at either side of the weld, or tapering, Table 2 may be used as guidance.
In this case, the effectiveness and coverage of the setup shall be verified by using reference blocks.
Selection of probes for full coverage of the complete weld thickness should follow Table 2. Care should
be taken to choose appropriate combinations of parameters. For example, in the thickness range 15 mm
to 35 mm a frequency of 10 MHz, a beam angle of 70° and a transducer size of 3 mm can be appropriate
for a thickness of 16 mm, but not for 32 mm thickness.
For testing levels A and B, it is recommended that the TOFD setup be verified by the use of reference blocks.
For testing levels C and D, all the setups chosen for the test object shall be verified by use of
reference blocks.
If setup parameters are not in accordance with Table 2, the capability shall be verified by using
reference blocks.
For in-service inspection the intersection point of the beam centrelines should be optimized for the
specified volume to be tested.
6 © ISO 2020 – All rights reserved

ISO 10863:2020(E)
Table 2 — Recommended TOFD setups for simple butt welds dependent on wall thickness
Beam angle
Centre
Thickness Depth range (longitudinal
Transducer
frequency
Number of Beam
waves)
size
TOFD setups intersection
t Δt f α
mm mm MHz ° mm
6 to 10 1 0 to t 15 70 2 to 3 2/3 of t
>10 to 15 1 0 to t 15 to 10 70 2 to 3 2/3 of t
>15 to 35 1 0 to t 10 to 5 70 to 60 2 to 6 2/3 of t
>35 to 50 1 0 to t 5 to 3 70 to 60 3 to 6 2/3 of t
0 to t/2 5 to 3 70 to 60 3 to 6 2/6 of t
>50 to 100 2
t/2 to t 5 to 3 60 to 45 6 to 12 5/6 of t
0 to t/3 5 to 3 70 to 60 3 to 6 2/9 of t
>100 to 200 3 t/3 to 2t/3 5 to 3 60 to 45 6 to 12 5/9 of t
2t/3 to t 5 to 2 60 to 45 6 to 20 8/9 of t
0 to t/4 5 to 3 70 to 60 3 to 6 2/12 of t
t/4 to t/2 5 to 3 60 to 45 6 to 12 5/12 of t
>200 to 300 4
t/2 to 3t/4 5 to 2 60 to 45 6 to 20 8/12 of t
11/12 of t; or t
3t/4 to t 3 to 1 50 to 40 10 to 20
for α ≤ 45°
8.3 Scan increment setting
The scan increment setting shall be dependent on the wall thickness to be tested. For thicknesses up to
10 mm, the scan increment shall be no more than 0,5 mm. For thicknesses between 10 mm and 150 mm,
the scan increment shall be no more than 1 mm. Above 150 mm, the scan increment shall be no more
than 2 mm.
8.4 Geometry considerations
Care should be taken when testing welds of complex geometry, e.g. welds joining materials of unequal
thickness, materials that are joined at an angle, or nozzles. As TOFD is based on the measurement of
time intervals of sound waves taking the shortest path between the point of emission and the point
of reception via points of reflection or diffraction, some areas of interest can be obscured. Additional
scans can overcome this problem in many cases.
Planning testing of complex geometries requires in-depth knowledge of sound propagation,
representative reference blocks and sophisticated software and is beyond the scope of this document.
8.5 Preparation of scanning surfaces
Scanning surfaces shall be wide enough to permit full coverage of the volume to be tested.
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 one of the probes and test surface greater than 0,5 mm. These requirements shall be
ensured by dressing, if necessary.
Scanning surfaces may be assumed to be satisfactory if the surface roughness, Ra, is not greater than
6,3 μm for machined surfaces, or not greater than 12,5 μm for shotblasted surfaces.
ISO 10863:2020(E)
8.6 Temperature
When using conventional probes and couplants, the surface temperature of the test object shall be in
the range 0 °C to 50 °C.
For temperatures outside this range, the suitability of the equipment shall be verified.
8.7 Couplant
In order to generate proper images, a couplant shall be used which provides a constant transmission of
ultrasound between the probes and the test object.
The couplant used for calibration shall be the same as that used in subsequent testing and post-
calibrations.
8.8 Provision of datum points
In order to ensure repeatability of the testing, a permanent reference system shall be applied.
9 Testing of base material
The base material does not generally require prior testing for laminations (typically by using straight-
beam probes), as they are detected during the TOFD weld testing. Nevertheless, the presence of
discontinuities in the base material adjacent to the weld can lead to obscured areas or to difficulties in
interpretation of the data.
10 Range and sensitivity settings
10.1 Settings
10.1.1 General
Setting of range and sensitivity in accordance with this document and ISO 16828 shall be carried out
prior to each testing. Any change of the TOFD setup, e.g. probe centre separation (PCS), requires a new
setting.
Noise should be minimized, e.g. by signal averaging.
10.1.2 Time window
The time window shall at least cover the depth range as shown in Table 2:
a) for full-thickness testing using only one setup, the time window recorded should start at least 1 µs
prior to the time of arrival of the lateral wave, and should extend beyond the first mode-converted
back-wall signal, where possible;
b) if more than one setup is used, the time windows shall overlap by at least 10 % of the depth range.
The start and extent of the time windows shall be verified on the test object.
10.1.3 Time-to-depth conversion
For a given PCS, setting of time-to-depth conversion is best carried out using the lateral wave signal and
the back-wall signal with the known material velocity.
This setting shall be verified (for all testing levels) by a suitable block of known thickness (accuracy
0,05 mm). At least one depth measurement shall be performed in the depth range of interest, typically
by recording a minimum of 20 A-scans.
8 © ISO 2020 – All rights reserved

ISO 10863:2020(E)
The measured thickness or depth shall be within 0,2 mm of the actual or known thickness or depth. For
curved components geometrical corrections can be necessary.
10.1.4 Sensitivity settings
For all testing levels, the sensitivity shall be set on the test object. The amplitude of the lateral wave
shall be between 40 % and 80 % of full screen height (FSH). In cases where the use of the lateral wave
is not appropriate (e.g. because of surface conditions, use of steep beam angles), the sensitivity shall be
set such that the amplitude of the back-wall signal is between 18 dB and 30 dB above FSH. When the
use of neither a lateral wave nor a back-wall signal is appropriate, sensitivity should be set such that the
material grain noise is between 5 % and 10 % of FSH.
For testing levels B, C, and D, it shall be verified by the use of the test block(s) that the sensitivity is
sufficient to detect real discontinuities in the respective depth zone or, if not available, machined
discontinuities (e.g. notches, side-drilled holes), see 10.3.
10.2 Checking of the settings
Checks to confirm the range and sensitivity 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 a reference block was used for the initial setup, the
same reference block should be used for subsequent checks. Alternatively, a smaller block with known
transfer properties may be used, provided that this is cross-referenced to the initial reference block.
Where a reference block was not used, but instead the test object was used for checking, then subsequent
checks shall be carried out at the same location as the initial check.
If deviations from the initial settings, in accordance with 10.1.3 and 10.1.4, are found during these
checks, the corrections given in Table 3 shall be carried out.
Table 3 — Sensitivity and range corrections
Sensitivity
Deviations ≤6 dB No action required; data may be corrected by software
Settings shall be corrected and all tests carried out since
Deviations >6 dB
the last valid check shall be repeated
Range
Deviations ≤0,5 mm or 2 % of depth range,
No action required
whichever is greater
Deviations >0,5 mm or 2 % of depth range, Settings shall be corrected and all tests carried out since
whichever is greater the last valid check shall be repeated
10.3 Reference blocks
10.3.1 General
Depending on the testing level, a reference block shall be used to determine the adequacy of the testing
(e.g. coverage, sensitivity setting). Recommendations for reference blocks are given in Annex A.
10.3.2 Material
The reference block should be made of similar material to the test object (e.g. with regard to sound
velocity, grain structure and surface condition).
ISO 10863:2020(E)
10.3.3 Dimensions and shape
The thickness of the reference block should be representative of the thickness of the test object.
Therefore, the thickness should be limited to a minimum and a maximum value related to the thickness
of the test object.
Thickness of reference blocks is recommended to be between 0,8 times and 1,5 times the thickness
of the test object with a maximum difference in thickness of 20 mm compared to the test object. Care
should be taken that on the centreline between the probes there is no angle smaller than 40° at the
bottom of the reference block (see Figure A.1). The minimum thickness of the reference block should be
chosen such that the beam intersection point of the chosen setup is always within the reference block
(see Figure A.2).
The length and width of the reference block should be chosen so that all the artificial
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