ISO 4761 2022

I NTE RNATI O NAL
STAN DARD
ISO
4761
Fi rs t ed ition
2 02 2 - 01
Non-destructive testing of welds —
Phased array ultrasonic testing (UTPA) for thin-walled steel components
— Acceptance levels
Essais non destructifs des assemblages soudés — Technique ultrasons
multi-éléments (UT-PA) pour les composants en acier à paroi mince
— Niveaux d’acceptation
Reference numb er
I SO 4761 : 2 0 2 2 (E )
© ISO 2 02 2
ISO 4761:2022(E)
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© ISO 2022
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Published in Switzerland
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ISO 4761:2022(E)
Contents
Page
Foreword
1
Scope
2
Normative references
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3
Terms and definitions . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . .
4
5
6
7
8
Symbols
Sensitivity setting and levels
Acceptance levels
Evaluation of indications
Acceptance criteria for two-sided testing
9
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8 .1
G enera l . . . . .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . 3
8.2
L ongitud i na l i nd ication s . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . . 3
8.3
Tran s vers e i nd ic ation s .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. 5
8 .4
Cu mu l ative leng th o f i nd ic ation s . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . 5
Acceptance criteria for single-sided testing
. . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . .
6
9.1
G enera l . . . . .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . 6
9. 2
L ongitud i na l i nd ication s . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . . 6
9. 3
Tran s vers e i nd ic ation s .. . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. 7
9.4
Cu mu l ative leng th o f i nd ic ation s . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . 7
Bibliography
. .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. . . . . . . . . .. .
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ISO 4761:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation o f national standards
bodies (ISO member bodies). The work o f 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 o f
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 di fferent approval criteria needed for the
di fferent types o f ISO documents should be noted. This document was dra fted in accordance with the
editorial rules o f the ISO/IEC Directives, Part 2 (see www. iso . org/direc tives) .
Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f
patent rights. ISO shall not be held responsible for identi fying any or all such patent rights. Details o f
any patent rights identified during the development o f the document will be in the Introduction and/or
on the ISO list o f patent declarations received (see www.iso.org/patents) .
Any trade name used in this document is in formation given for the convenience o f users and does not
constitute an endorsement.
For an explanation o f the voluntary nature o f standards, the meaning o f ISO specific terms and
expressions related to con formity assessment, as well as in formation about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www. iso. org/iso/foreword. htm l .
This document was prepared by Technical Committee ISO/TC 44,
Subcommittee SC 5, Testing and inspection of welds.
Welding and allied processes,
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing o f these bodies can be found at www. iso . org/memb ers . htm l .
O fficial interpretations o f ISO/TC 44 documents, where they exist, are available from this page:
https://committee.iso.org/sites/tc44/home/interpretation.html .
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INTERNATIONAL STANDARD
ISO 4761:2022(E)
Non-destructive testing of welds — Phased array ultrasonic
testing (UT-PA) for thin-walled steel components —
Acceptance levels
1 Scope
This document specifies acceptance levels for the phased array ultrasonic testing technique (UT-PA) o f
full-penetration welds in low-alloy and/or fine-grained steels in the wall thickness range from 3,2 mm
to 8 mm which correspond to the quality levels o f ISO 5817.
These acceptance levels are applicable to indications detected according to ISO 20601.
2 Normative references
The following documents are re ferred to in the text in such a way that some or all o f their content
constitutes requirements o f this document. For dated re ferences, only the edition cited applies. For
undated re ferences, the latest edition o f the re ferenced document (including any amendments) applies.
ISO 5577, Non-destructive testing — Ultrasonic testing — Vocabulary
ISO 20601,
Non-destructive testing of welds — Ultrasonic testing — Use of automated phased array
technology for thin-walled steel components
ISO 23243, Non-destructive testing — Ultrasonic testing with arrays — Vocabulary
3 Terms and definitions
For the purposes o f this document, the terms and definitions given in ISO 5577, ISO 20601 and
ISO 23243 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http s://www
. org/obp
— IEC Electropedia: available at https://www.electropedia . org/
4 Symbols
l
indication length
l1 , l2
length o f individual indications
lc
correc ted length
lc u
cumulative length
lw
weld length
t
thicknes s
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ISO 4761:2022(E)
5 Sensitivity setting and levels
The setting o f the sensitivity shall be per formed on a 1,0 mm diameter side-drilled hole as specified
in ISO 20601, this is also the re ference level. This sensitivity setting shall be used for the subsequent
tes ting.
Three levels as defined in ISO 5577 are to be used:
a) re ference level, level defined by the echo amplitude o f a defined re ference reflector;
b) acceptance level, level defining limits for acceptance regarding echo height, position, classification
(i f applicable) and number o f indications or size o f discontinuities;
c) evaluation level, level above or below which indications shall be evaluated or examined further.
All levels are linked to the re ference reflector and are specified in Clauses 8 and 9 .
6 Acceptance levels
Three di fferent acceptance levels are defined. The relation between these acceptance levels and the
quality levels as mentioned in accordance with ISO 5817 are given in Table 1 .
Table 1 — Related levels for phased array ultrasonic testing of small wall thickness
Quality level according to
ISO 5817
B (stringent)
C (intermediate)
D (moderate)
Special application
Testing level according to
ISO 20601
Acceptance level according to this
document
C
1
C
2
C
3
D
By agreement
7 Evaluation of indications
Indications detected when applying ISO 20601 and having an amplitude above the evaluation level
(re ference level -12 dB) shall be evaluated according to the specified acceptance level by using the
indication length and maximum amplitude. Unless specified otherwise, indications from the object
geometry, such as weld rein forcement, are considered not relevant.
For two-sided testing, Clause 8 shall be applied. For single-sided testing, Clause 9 shall be applied.
The length o f an indication shall be determined by measuring the length along the weld using the 6 dB
drop method. Only for un focused sound beams in lateral direction, a length correction may be applied
according to Formula (1) .
= ls ×
l
c
D
O
− 2d
(1)
DO
where
l
is the corrected length;
l
is the length measured along the sur face;
c
s
D
is the outside diameter;
d
is the depth o f indication.
O
2
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ISO 4761:2022(E)
When reporting o f indications below the acceptance level is specified, the details for reporting shall
also be specified.
8 Acceptance criteria for two-sided testing
8.1 General
When indications are detected, length and maximum amplitude shall be determined in accordance
Clause 7.
with
Indications shall be evaluated according to their acceptance level and the acceptance criteria listed in
this clause.
All indications with an amplitude greater than the re ference level -12 dB shall be evaluated for
acceptance by using the criteria given in 8.2, 8.3 and 8.4 .
8.2 Longitudinal indications
Table 2 — Criteria for acceptance level 1
Indication length , l
Evaluation level
Maximum allowable amplitude
mm
dB relative to the re ference level
-1 2
dB relative to the re ference level
+6
+2
-1 2
-10
≤4
4 < l ≤ 6
l
l> 6
Key
Y
indication length, in mm
amplitude, in dB
1
reference level
X
2
3
-1 2
acceptance level 1
evaluation level
Figure 1 — Criteria for acceptance level 1
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ISO 4761:2022(E)
Table 3 — Criteria for acceptance level 2
Indication length , l
Evaluation level
Maximum allowable amplitude
mm
d B rel ative to the re ference level
d B rel ative to the re ference le vel
l≤ 4
-1 2
+6
4 < l≤ 7
-1 2
+3 , 5
l> 7
-1 2
-10
Key
X
indicatio n length, in mm
Y
amp litude, in dB
1
reference level
2
accep tance level 2
3
evaluatio n level
Figure 2 — Criteria for acceptance level 2
Table 4 — Criteria for acceptance level 3
4
Indication length , l
Evaluation level
Maximum allowable amplitude
mm
d B rel ative to the re ference level
d B rel ative to the re ference le vel
l≤ 4
-1 2
+6
4 < l≤ 8
-1 2
+5
l> 8
-1 2
-10
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ISO 4761:2022(E)
Key
X
indicatio n length, in mm
Y
amp litude, in dB
1
reference level
2
accep tance level 3
3
evaluatio n level
Figure 3 — Criteria for acceptance level 3
8.3 Transverse indications
When de te c tion o f tra n s vers e i nd ic ation s i s s p e ci fie d, the s e i nd ic ation s a re on ly accep table i f ampl itude
and leng th c an b e de term i ne d a nd me e t the accep tance level s s tate d i n 8 . 2 .
8.4 Cumulative length of indications
T he c u mu l ative leng th o f a l l i nd i vidua l ly accep table i nd ic ation s ab ove the eva luation level sh a l l b e
c a lc u late d with i n a s p e ci fie d s e c tion o f weld leng th,
lw,
a s the s u m o f leng th s o f b o th s i ngle i nd ic ation s
and l i ne arly a l igne d i nd ic ation s (s e e Figure 4) .
Key
lcu
cumulative length,
lw
weld length
lcu = l2 + l3 + l4 + l5 + l6
ln
length o f individual indicatio ns , where
n
= 1 …7
Figure 4 — Cumulative length of indications
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ISO 4761:2022(E)
For wall thickness t, the sum o f the lengths o f the individual indications measured along the weld over
a length o f 12 t shall be:
a) ≤3,5 t for acceptance level 1;
b) ≤4,0 t for acceptance level 2;
c) ≤4,5 t for acceptance level 3.
9 Acceptance criteria for single-sided testing
9.1 General
When indications are detected, length and maximum amplitude shall be determined in accordance
with Clause 7.
Indications shall be evaluated according to their acceptance level and the acceptance criteria listed in
this clause.
All indications with an amplitude greater than the re ference level -12 dB shall be evaluated for
acceptance by using the criteria given in 9.2, 9.3 and 9.4 .
For single-sided testing no acceptance criteria are defined for acceptance level 1 (stringent).
9.2 Longitudinal indications
Table 5 — Criteria for acceptance level 2 for single-sided testing
Indication length , l
Evaluation level
Maximum allowable amplitude
mm
dB relative to the re ference level
-1 2
dB relative to the re ference level
+3,5
-1 2
-10
l
≤4
l>
Key
4
Y
indication length, in mm
amplitude, in dB
1
reference level
X
2
3
acceptance level 2
evaluation level
Figure 5 — Criteria for acceptance level 2 for single-sided testing
6
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ISO 4761:2022(E)
Table 6 — Criteria for acceptance level 3 for single-sided testing
Indication length l
Evaluation level
Maximum allowable amplitude
mm
d B rel ati ve to the re ference le vel
d B rel ative to the re ference le vel
l≤
5,5
-1 2
+5
l>
5,5
-1 2
-10
Key
Y
amp litude, in dB
X
indicatio n length, in mm
1
reference level
2
accep tance level 3
3
evaluatio n level
Figure 6 — Criteria for acceptance level 3 for single-sided testing
9.3 Transverse indications
When de te c tion o f tra n s vers e i nd ic ation s i s s p e ci fie d, the s e i nd ic ation s a re on ly accep table i f ampl itude
and leng th c an b e de term i ne d a nd me e t the accep tance level s s tate d i n 9. 2 .
9.4 Cumulative length of indications
T he c u mu l ative leng th o f a l l i nd i vidua l ly accep table i nd ic ation s ab ove the eva luation level sh a l l b e
c a lc u late d with i n a s p e c i fie d s e c tion o f weld leng th,
lw,
as the s um o f leng th s o f b o th s i ngle i nd ic ation s
and l i ne arly a l igne d i nd ic ation s (s e e Figure 4) .
t, the
t sha l l b e:
For wa l l th ickne s s
a leng th o f 1 2
s u m o f the leng th s o f the i nd ividua l i nd ic ation s me a s u re d a long the weld over
a)
≤ 4, 0
t for
accep ta nce level 2 ;
b)
≤ 4, 5
t for
accep tance level 3 .
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ISO 4761:2022(E)
Bibliography
[1]
ISO 5817, Welding — Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding
excluded) — Quality levels for imperfections
[2]
ISO 9712 ,
[3]
ISO 11666,
Non-destructive testing of welds — Ultrasonic testing — Acceptance levels
ISO 13588,
Non-destructive testing ofwelds — Ultrasonic testing — Use ofautomated phased array
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
[4]
[5]
[6]
[7 ]
8
Non-destructive testing — Qualification and certification of NDT personnel
technology
assessment
Development of Acceptance Criteria for Ultrasonic Phased Array Examination
of Steel Components with Small Wall Thickness, 2019
KINT project report
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ISO 4761:2022(E)
ICS 2 5 .1 60.40
Price based on 8 pages
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