oSIST prEN ISO 5817:2021

Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) - Quality levels for imperfections (ISO/DIS 5817:2021)

Schweißen - Schmelzschweißverbindungen an Stahl, Nickel, Titan und deren Legierungen (ohne Strahlschweißen) - Bewertungsgruppen von Unregelmäßigkeiten (ISO/DIS 5817:2021)

Dieses Dokument enthält Bewertungsgruppen von Unregelmäßigkeiten an Schmelzschweißverbindungen (ausgenommen Strahlschweißen) für alle Sorten von Stahl, Nickel, Titan und deren Legierungen. Es gilt für Werkstückdicken ≥ 0,5 mm. Es behandelt voll durchgeschweißte Stumpfnähte und alle Arten von Kehlnähten. Die Grundsätze dieses Dokuments dürfen auch für teilweise durchgeschweißte Stumpfnähte angewendet werden.
Bewertungsgruppen für strahlgeschweißte Verbindungen an Stahl enthält ISO 13919-1.
Die drei Bewertungsgruppen sind so festgelegt, dass sie eine breite Anwendung in der schweißtechnischen Fertigung erlauben. Sie werden bezeichnet durch Kennbuchstaben B, C und D. Bewertungsgruppe B entspricht den höchsten Anforderungen an die Schweißnaht.
Es werden einige Arten von Belastungen berücksichtigt, z. B. statische Belastung, Wärmebelastung, Korrosionsbelastung, Druckbelastung. Zusätzliche Richtlinien für Ermüdungsbeanspruchungen sind in Anhang C angegeben.
Die Bewertungsgruppen beziehen sich auf die Produktion und auf eine gute Fertigungsqualität.
Dieses Dokument gilt für:
a) unlegierte und legierte Stähle;
b) Nickel und Nickellegierungen;
c) Titan und Titanlegierungen;
d) manuelles, mechanisiertes und automatisiertes Schweißen;
e) alle Schweißpositionen;
f) alle Schweißverbindungen, z. B. Stumpfnähte, Kehlnähte und Rohrabzweigungen;
g) die folgenden Schweißprozesse und ihre zugeordneten Einzelprozesse nach ISO 4063:
- 11 Metall-Lichtbogenschweißen ohne Gasschutz;
- 12 Unterpulverschweißen;
- 13 Metall-Schutzgasschweißen;
- 14 Wolfram-Schutzgasschweißen;
- 15 Plasmaschweißen;
- 31 Gasschweißen mit Sauerstoff-Brenngas-Flamme (nur für Stahl).
Metallurgische Gesichtspunkte, z. B. Korngröße, Härte, werden von diesem Dokument nicht erfasst.

Soudage - Assemblages en acier, nickel, titane et leurs alliages soudés par fusion (soudage par faisceau exclu) - Niveaux de qualité par rapport aux défauts (ISO/DIS 5817:2021)

Varjenje - Talilno zvarjeni spoji na jeklu, niklju, titanu in njihovih zlitinah (izključeno varjenje s snopom) - Stopnje sprejemljivosti nepravilnosti (ISO/DIS 5817:2021)

General Information

• Status: Not Published
• Public Enquiry End Date: 01-Oct-2021
• ICS: 25.160.40 - Welded joints and welds
• Technical Committee: VAR - Welding
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 12-Aug-2021
• Due Date: 30-Dec-2021
• Completion Date: 04-Oct-2021
• Ref Project: prEN ISO 5817 - Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) - Quality levels for imperfections (ISO/DIS 5817:2021)

RELATIONS

• Revised: SIST EN ISO 5817:2014 - Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) - Quality levels for imperfections (ISO 5817:2014)
• Effective Date: 01-Sep-2021

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 5817:2021
01-september-2021

Varjenje - Talilno zvarjeni spoji na jeklu, niklju, titanu in njihovih zlitinah (izključeno

varjenje s snopom) - Stopnje sprejemljivosti nepopolnosti (ISO/DIS 5817:2021)

Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding

excluded) - Quality levels for imperfections (ISO/DIS 5817:2021)
Schweißen - Schmelzschweißverbindungen an Stahl, Nickel, Titan und deren
Legierungen (ohne Strahlschweißen) - Bewertungsgruppen von Unregelmäßigkeiten
(ISO/DIS 5817:2021)

Soudage - Assemblages en acier, nickel, titane et leurs alliages soudés par fusion

(soudage par faisceau exclu) - Niveaux de qualité par rapport aux défauts (ISO/DIS

5817:2021)
Ta slovenski standard je istoveten z: prEN ISO 5817
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
oSIST prEN ISO 5817:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 5817:2021
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oSIST prEN ISO 5817:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 5817
ISO/TC 44/SC 10 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-08-05 2021-10-28
Welding — Fusion-welded joints in steel, nickel, titanium
and their alloys (beam welding excluded) — Quality levels
for imperfections

Soudage — Assemblages en acier, nickel, titane et leurs alliages soudés par fusion (soudage par faisceau

exclu) — Niveaux de qualité par rapport aux défauts
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 5817:2021(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 2021
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols .......................................................................................................................................................................................................................... 3

5 Assessment of imperfections ................................................................................................................................................................... 4

Annex A (informative) Examples of determination of percentage (%) porosity .................................................20

Annex B (informative) Additional information and guidelines for use of this document .........................22

Annex C (informative) Additional requirements for welds in steel subject to fatigue ..................................23

Bibliography .............................................................................................................................................................................................................................26

© ISO 2021 – All rights reserved iii
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(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 10, Quality management in the field of welding.

This fourth edition cancels and replaces the third edition (ISO 5817:2014), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— the document was editiorial updated,

— figures to imperfection no. 1.4, 1.11, 1.16, 1.19, 1.11 and 4.1 in Table 1 have been changed.

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.
iv © ISO 2021 – All rights reserved
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
Introduction

This document should be used as a reference in the drafting of application codes and/or other application

standards. It contains a simplified selection of fusion weld imperfections based on the designations

given in ISO 6520-1.

Some of the imperfections described in ISO 6520-1 have been used directly and some have been grouped

together. The basic numerical referencing system from ISO 6520-1 has been used.

The purpose of This document is to define dimensions of typical imperfections which might be

expected in normal fabrication. It may be used within a quality system for the production of welded

joints. It provides three sets of dimensional values from which a selection can be made for a particular

application. The quality level necessary in each case should be defined by the application standard or

the responsible designer in conjunction with the manufacturer, user and/or other parties concerned.

The quality level shall be prescribed before the start of production, preferably at the enquiry or order

stage. For special purposes, additional details may be prescribed. If the welds will be subsequently

coated with a protective coating, lining or paint, the welds might require more thorough post weld

treatment or surface finishing to achieve the requirements in ISO 8501-3.

The quality levels given in this document provide basic reference data and are not specifically related

to any particular application. They refer to types of welded joint in fabrication and not to the complete

product or component itself. It is possible, therefore, that different quality levels are applied to

individual welded joints in the same product or component.

It would normally be expected that for a particular welded joint the dimensional limits for imperfections

could all be covered by specifying one quality level. In some cases, it may be necessary to specify

different quality levels for different imperfections in the same welded joint. The choice of quality

level for any application should take account of design considerations, subsequent processing (e.g.

surfacing), mode of stressing (e.g. static, dynamic), service conditions (e.g. temperature, environment)

and consequences of failure. Economic factors are also important and should include not only the cost

of welding but also of inspection, testing and repair.

Although this document includes types of imperfection relevant to the fusion welding processes listed

in Clause 1, only those which are applicable to the process and application in question need to be

considered.

Imperfections are quoted in terms of their actual dimensions, and their detection and evaluation

may require the use of one or more methods of non-destructive testing. The detection and sizing of

imperfections is dependent on the testing methods and the extent of testing specified in the application

standard or contract.

This document does not address the methods used for the detection of imperfections. However,

ISO 17635 contains a correlation between the quality level and acceptance level for different NDT

methods.

This document is directly applicable to visual testing of welds and does not include details of

recommended methods of detection or sizing by non-destructive means. It should be considered

that there are difficulties in using these limits to establish appropriate criteria applicable to non-

destructive testing methods such as ultrasonic testing (UT), radiographic testing (RT), eddy current

testing (ET), penetrant testing (PT), magnetic particle testing (MT) and may need to be supplemented

by requirements for inspection, examining and testing.

The values given for imperfections are for welds produced using normal welding practice. Requirements

for smaller (more stringent) values as stated in quality level B may include additional manufacturing

processes, e.g. grinding, TIG dressing.
Annex C gives additional guidance for welds subject to fatigue.
© ISO 2021 – All rights reserved v
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oSIST prEN ISO 5817:2021
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oSIST prEN ISO 5817:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 5817:2021(E)
Welding — Fusion-welded joints in steel, nickel, titanium
and their alloys (beam welding excluded) — Quality levels
for imperfections
1 Scope

This document provides quality levels of imperfections in fusion-welded joints (except for beam

welding) in all types of steel, nickel, titanium and their alloys. It applies to material thickness ≥ 0,5 mm.

It covers fully penetrated butt welds and all fillet welds. Its principles can also be applied to partial-

penetration butt welds.
Quality levels for beam-welded joints in steel are presented in ISO 13919-1.

Three quality levels are given in order to permit application to a wide range of welded fabrication. They

are designated by symbols B, C and D. Quality level B corresponds to the highest requirement on the

finished weld.

Several types of loads are considered, e.g. static load, thermal load, corrosion load, pressure load.

Additional guidance on fatigue loads is given in Annex C.
The quality levels refer to production and good workmanship.
This document is applicable to
a) non-alloy and alloy steels,
b) nickel and nickel alloys,
c) titanium and titanium alloys,
d) manual, mechanized and automated welding,
e) all welding positions,
f) all types of welds, e.g. butt welds, fillet welds and branch connections

g) the following welding processes and their sub-processes, as defined in ISO 4063:

— 11 metal arc welding without gas protection;
— 12 submerged arc welding;
— 13 gas-shielded metal arc welding;
— 14 gas-shielded arc welding with non-consumable tungsten electrode;
— 15 plasma arc welding;
— 31 oxyfuel gas welding (for steel only).

Metallurgical aspects, e.g. grain size, hardness, are not covered by this document.

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 2021 – All rights reserved 1
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)

ISO 6520-1, Welding and allied processes — Classification of geometric imperfections in metallic

materials — Part 1: Fusion welding
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/TR 25901 (all parts) 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 https:// www .electropedia .org/
3.1
quality level

description of the quality of a weld on the basis of type, size and amount of selected imperfections

3.2
fitness for purpose

ability of a product, process or service to serve a defined purpose under specific conditions

3.3
short imperfections in welds 100 mm long or longer

imperfections whose total length is not greater than 25 mm in the 100 mm of the weld which contains

the greatest number of imperfections
3.4
short imperfections in welds less than 100 mm long

imperfections whose total length is not greater than 25 % of the length of the weld

3.5
systematic imperfections

imperfections that are repeatedly distributed in the weld over the weld length to be examined, the size

of a single imperfection being within the specified limits
3.6
projected area

area where imperfections distributed along the volume of the weld under consideration are imaged

two-dimensionally

Note 1 to entry: In contrast to the cross-sectional area, the occurrence of imperfections is dependent on the weld

thickness when exposed radiographically (see Figure 1).
3.7
cross-sectional area
area to be considered after fracture or sectioning
3.8
smooth weld transition

even surface with no irregularities or sharpness at the transition between the weld bead and the parent

material and/or the adjacent welding bead(s)
3.9
fatigue class
FATx

classification reference to S-N curve, in which x is the stress range in MPa at 2 · 10 cycles

Note 1 to entry: Fatigue properties are described by S-N-Curves (Stress-Number of cycle- curves).

Note 2 to entry: See Annex C.
2 © ISO 2021 – All rights reserved
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
Key
1 direction of X-rays 3 6-fold thickness 5 2-fold thickness
2 4 pores per volume unit 4 3-fold thickness 6 1-fold thickness

Figure 1 — Radiographic films of specimens with identical occurrence of pores per volume unit

4 Symbols
The following symbols are used in Table 1 and Table C.1.
a nominal throat thickness of the fillet weld (see also ISO 2553)

a actual throat thickness (throat thickness of the finalized weld) (see ISO TR 25901-1)

A area surrounding the gas pores
b width of weld reinforcement
d diameter of gas pore
d diameter of area surrounding the gas pores
h height or width of imperfection
l length of imperfection in longitudinal direction of the weld
l length of projected or cross-sectional area
s nominal butt weld thickness
t wall or plate thickness (nominal size)
w width of the weld or width or height of the cross-sectional area
z leg length of a fillet weld (see also ISO 2553)
α angle of weld toe
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
β angle of angular misalignment
i penetration in fillet welds
r radius of weld toe
5 Assessment of imperfections
Limits for imperfections are given in Table 1.

If, for the detection of imperfections, macro-examination is used, only those imperfections shall be

considered which can be detected with a maximum of tenfold magnification. Excluded from this are

micro lack of fusion (see Table 1, 1.5) and microcracks (see Table 1, 2.2).

Systematic imperfections are only permitted in quality level D, provided other requirements of Table 1

are fulfilled.

A welded joint should usually be assessed separately for each individual type of imperfection (see

Table 1, 1.1 to 3.2).

Different types of imperfection occurring at any cross-section of the joint need special consideration

(see multiple imperfections in Table 1, 4.1).

The limits for multiple imperfections (see Table 1) are only applicable for cases where the requirements

for a single imperfection are not exceeded.

Any two adjacent imperfections separated by a distance smaller than the major dimension of the

smaller imperfection shall be considered as a single imperfection.
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oSIST prEN ISO 5817:2021
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© ISO 2021 – All rights reserved 5
Table 1 — Limits for imperfections
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B
1 Surface imperfections
1.1 100 Crack ≥ 0,5 Not permitted Not permitted Not permitted
1.2 104 Crater crack ≥ 0,5 Not permitted Not permitted Not permitted

1.3 2017 Surface pore On the weld face or the weld root 0,5 to 3 butt welds d ≤ 0,3 s Not permitted Not permitted

Maximum dimension of a single pore fillet welds d ≤ 0,3 a
> 3 butt welds d ≤ 0,3 s, but butt welds d ≤ 0,2 s, but Not permitted
max. 3 mm max. 2 mm
fillet welds d ≤ 0,3 a , fillet welds d ≤ 0,2 a , but
A A
but max. 3 mm max. 2 mm

1.4 2025 End crater — butt welds 0,5 to 3 butt welds h ≤ 0,2 t Not permitted Not permitted

pipe
d ≤ 0,3 s
fillet welds h ≤ 0,2a ,
d ≤ 0,3 a

— fillet welds > 3 butt welds h ≤ 0,2 t, but butt welds h ≤ 0,1 t, but Not permitted

max. 2 mm max. 1 mm
d ≤ 0,3 s, but max. 3 mm d ≤ 0,2 s, but max. 2 mm
fillet welds h ≤ 0,2 a , fillet welds h ≤ 0,1 a , but
A A
but max. 2 mm max. 1 mm
d ≤ 0,3 a , but max. d ≤ 0,2 a , but max. 2 mm
A A
3 mm
1.5 401 Lack of fusion — ≥ 0,5 Not permitted Not permitted Not permitted
(incomplete
fusion)

Micro lack of Only detectable by micro examination ≥ 0,5 Permitted Permitted Not permitted

fusion

1.6 4021 Incomplete Only for single side butt welds ≥ 0,5 Short imperfections: Not permitted Not permitted

root penetra- h ≤ 0,2 t but max. 2 mm
tion
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oSIST prEN ISO 5817:2021
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6 © ISO 2021 – All rights reserved
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B

1.7 5011 Continuous Smooth transition is required. 0,5 to 3 Short imperfections: Short imperfections: Not permitted

undercut This is not regarded as a systematic imperfec- h ≤ 0,2 t h ≤ 0,1 t
tion.

5012 Intermittent > 3 h ≤ 0,2 t, but max. 1 mm h ≤ 0,1 t, but max. 0,5 mm h ≤ 0,05 t, but max.

undercut 0,5 mm
(short imper-
fection)

1.8 5013 Shrinkage Smooth transition is required. 0,5 to 3 Short imperfections: Short imperfections: Not permitted

grooves h ≤ 0,1 t + 0,2 mm h ≤ 0,1 t
> 3 Short imperfections: Short imperfections: Short imperfections:
h ≤ 0,2 t, but max. 2 mm h ≤ 0,1 t, but max.1 mm h ≤ 0,05 t, but max.
0,5 mm

1.9 502 Excess weld Smooth transition is required between the cap ≥ 0,5 h ≤ 0,25 b + 1 mm, but h ≤ 0,15 b + 1 mm , but h ≤ 0,1 b + 1 mm ,but

metal (butt of the weld and the plate surface and/or the adja- max. 10 mm max. 7 mm max. 5 mm

weld) cent welding bead(s)
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
© ISO 2021 – All rights reserved 7
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B

1.10 503 Excessive con- Smooth transition is required between the cap ≥ 0,5 h ≤ 0,25 b + 1 mm, but h ≤ 0,15 b + 1 mm, but h ≤ 0,1 b + 1 mm, but

vexity (fillet of the weld and the plate surface and/or the adja- max. 5 mm max. 4 mm max. 3 mm

weld) cent welding bead(s)
1.11 504 Excessive 0,5 to 3 h ≤ 0,6 b + 1 mm h ≤ 0,3 b + 1 mm h ≤ 0,1 b + 1 mm
penetration
> 3 h ≤ 1,0 b + 1 mm, but h ≤ 0,45 b +1 mm,but max. h ≤ 0,2 b + 1 mm,but
max. 5 mm 4 mm max. 3 mm
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
8 © ISO 2021 – All rights reserved
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B
1.12 505 Incorrect weld — butt welds ≥ 0,5 α ≥ 90° α ≥ 110° α ≥ 150°
toe
— fillet welds ≥ 0,5 α ≥ 90° α ≥ 100° α ≥ 110°
α ≥ α and α ≥ α
1 2
1.13 506 Overlap ≥ 0,5 h ≤ 0,2 b Not permitted Not permitted

1.14 509 Sagging Smooth transition is required 0,5 to 3 Short imperfections: Short imperfections: Not permitted

h ≤ 0,25 t h ≤ 0,1 t

511 Incompletely > 3 Short imperfections: Short imperfections: Short imperfections:

filled groove h ≤ 0,25 t, but max. h ≤ 0,1 t, but max. 1 mm h ≤ 0,05 t, but max.
2 mm 0,5 mm
1.15 510 Burn through — ≥ 0,5 Not permitted Not permitted Not permitted
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
© ISO 2021 – All rights reserved 9
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B

1.16 512 Excessive In cases where an asymmetric fillet weld has not ≥ 0,5 h ≤ 0,2 a + 2 mm h ≤ 0,15 a + 2 mm h ≤ 0,15 a + 1,5 mm

A A A
asymmetry been prescribed.
of fillet weld
(excessive
unequal leg
length)
h= |Z - Z |
1 2

1.17 515 Root concavity Smooth transition is required. 0,5 to 3 h ≤ 0,1 t + 0,2 mm Short imperfections: Not permitted

h ≤ 0,1 t
> 3 Short imperfections: Short imperfections: Short imperfections:
h ≤ 0,2 t, but max. 2 mm h ≤ 0,1 t, but max. 1 mm h ≤ 0,05 t, but max.
0,5 mm
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oSIST prEN ISO 5817:2021
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10 © ISO 2021 – All rights reserved
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B

1.18 516 Root porosity Spongy formation at the root of a weld due to ≥ 0,5 Locally permitted Not permitted Not permitted

bubbling of the weld metal at the moment of
solidification (e. g. lack of gas backing)
1.19 517 Poor restart ≥ 0,5 Permitted Not permitted Not permitted
The limit depends on
the type of imperfec-
tion occurred due to
restart.

1.20 5213 Insufficient Not applicable to processes with proof of greater 0,5 to 3 Short imperfections: Short imperfections: Not permitted

throat thick- depth of penetration h ≤ 0,1 a + 0,2 mm h ≤ 0,2 mm
ness
> 3 Short imperfections: Short imperfections: Not permitted
h ≤ 0,1 a + 0,3 mm, but h ≤ 0,1 a + 0,3 mm,but
max. 2 mm max. 1 mm

1.21 5214 Excessive The actual throat thickness of the fillet weld is ≥ 0,5 Permitted h ≤ 0,2 a + 1 mm, but max. h ≤ 0,15 a + 1 mm, but

throat thick- too large. 4 mm max. 3 mm
ness
1.22 601 Stray arc — ≥ 0,5 Permitted, if the prop- Not permitted Not permitted
erties of the parent
metal are not affected.
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oSIST prEN ISO 5817:2021
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© ISO 2021 – All rights reserved 11
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B

1.23 602 Spatter — ≥ 0,5 Acceptance depends on Acceptance depends on Acceptance depends on

application, e.g. materi- application, e.g. material, application, e.g. material,

al, corrosion protection corrosion protection corrosion protection

1.24 610 Temper colour — ≥ 0,5 Acceptance depends on Acceptance depends on Acceptance depends on

(Discoloura- application, e.g. materi- application, e.g. material, application, e.g. material,

tion) al, corrosion protection corrosion protection corrosion protection
2 Internal imperfections

2.1 100 Cracks All types of crack except microcracks and crater ≥ 0,5 Not permitted Not permitted Not permitted

cracks

2.2 1001 Microcracks A crack usually only visible under the microscope ≥ 0,5 Permitted Acceptance depends on Acceptance depends on

(50 × ) type of parent metal with type of parent metal
particular reference to with particular refer-
crack sensitivity ence to crack sensitivity
2.3 2011 Gas pore The following conditions and limits for imper-
fections shall be fulfilled. See also Annex A for
2012 Uniformly
information.
distributed

a1) Maximum dimension of the area of the ≥ 0,5 For single layer: ≤ 2,5 % For single layer: ≤ 1,5 % For single layer: ≤ 1 %

porosity
imperfections (inclusive of systematic imperfec-
For multi-layer: ≤ 5 % For multi-layer: ≤ 3 % For multi-layer: ≤ 2 %
tion) related to the projected area
NOTE The porosity in the project area depends
on the numbers of layers (volume of the weld).
a2) Maximum dimension of the cross-sectional ≥ 0,5 ≤ 2,5 % ≤ 1,5 % ≤ 1 %
area of the imperfections (inclusive of systematic
imperfection) related to the fracture area (only
applicable to test pieces: production test, welder
or procedure qualification tests)
b) Maximum dimension for a single pore for ≥ 0,5

— butt welds d ≤ 0,4 s, but max. 5 mm d ≤ 0,3 s, but max. 4 mm d ≤ 0,2 s, but max. 3 mm

— fillet welds d ≤ 0,4 a, but max. 5 mm d ≤ 0,3 a, but max. 4 mm d ≤ 0,2 a, but max. 3 mm

---------------------- Page: 19 ----------------------
oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
12 © ISO 2021 – All rights reserved
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B
2.4 2013 Clustered ≥ 0,5 d ≤ 25 mm d ≤ 20 mm d ≤ 15 mm
A A A
(localized)
or or or
porosity
d ≤ w d ≤ w d ≤ w /2
A, max p A, max p A, max p
Reference length for l is 100 mm.
The total gas pore area within the cluster is rep-
resented by a circle of diameter d surrounding
all the gas pores.
The requirement for a single gas pore shall be
met by all the gas pores within this circle.
A permitted porous area shall be local. The possi-
bility of the pore cluster masking other imperfec-
tions shall be taken into consideration.
If D is less than d or d , whichever is smaller,
A1 A2
then the total gas pore area is represented by a
circle of diameter d , where d = d + d + D.
AC AC A1 A2
Systematic cluster porosity is not permitted.
d corresponds to d , d or d , whichever is
A A1 A2 AC
applicable.
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oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
© ISO 2021 – All rights reserved 13
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No. Remarks
ISO 6520-1 designation
D C B

2.5 2014 Linear poros- — butt welds ≥ 0,5 h ≤ 0,4 s, but max. 4 mm h ≤ 0,3 s, but max. 3 mm h ≤ 0,2 s, but max. 2 mm

ity
l ≤ s, but max. 75 mm l ≤ s, but max. 50 mm l ≤ s, but max. 25 mm

— fillet welds ≥ 0,5 h ≤ 0,4 a, but max. 4 mm h ≤ 0,3 a, but max. 3 mm h ≤ 0,2 a, but max. 2 mm

l ≤ a, but max. 75 mm l ≤ a, but max. 50 mm l ≤ a, but max. 25 mm
Case 1 (D > d )
Case 2 (D < d )
Reference length for l is 100 mm.
For case 1: d = h
For case 2: d + d + D = h
1 2
---------------------- Page: 21 ----------------------
oSIST prEN ISO 5817:2021
ISO/DIS 5817:2021(E)
14 © ISO 2021 – All rights reserved
Table 1 (continued)
t Limits for imperfections for quality levels
Reference to Imperfection
No.
...