Chain components for lifting purposes -- Forged eye hook with point and latch -- Grade 4, stainless steel, solution annealed

This document specifies the requirements for forged eye hooks with point and latch of grade 4 from stainless steel and solution annealed for use preferably as a component in chain slings of welded construction of grade 4 from stainless steel and solution annealed. IMPORTANT — For other applications, e.g. steel wire rope slings or textile slings, it is important that the hook design is checked to ensure its fitness for a safe use. NOTE 1   The grade for the hook according to this document is taken from the grade of the sling chain according to ISO 1835. Both (sling chains and hooks) have identical scopes and values for the working load limit, WLL, according to Table 2 and values for the mechanical requirements according to Table 3. Thus, the direct correlation of hooks to the sling chain is given by the WLL and especially the code system on the product body itself. The grade of the hook does not define any values of the tensile strength of the hook material. For further information, see Annex B. The range of the nominal diameter, dn, of the associated sling chain according to ISO 1835 is from 4 mm to 22 mm. Hooks according to this document are for use in the temperature range –100 °C to +400 °C. These hooks are solution annealed in the finished condition and can therefore be used without restrictions with regard to the corrosion resistance of the steels according to 5.1. NOTE 2   The term “eye hook with point and latch” is taken from ISO 1837:2003, Figure 5.

Éléments de chaînes de levage -- Crochets de levage forgés en acier à bec et à œil -- Grade 4, acier inoxydable, recuit d’homogénéisation

General Information

Status
Published
Publication Date
18-Aug-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
21-Jul-2021
Completion Date
20-Jul-2021
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INTERNATIONAL ISO
STANDARD 4779
Second edition
2021-08
Chain components for lifting
purposes — Forged eye hook with
point and latch — Grade 4, stainless
steel, solution annealed
Éléments de chaînes de levage — Crochets de levage forgés en acier à
bec et à œil — Grade 4, acier inoxydable, recuit d’homogénéisation
Reference number
ISO 4779:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 4779:2021(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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 4779:2021(E)
Contents Page

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

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

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

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

4 Dimensions and designation ................................................................................................................................................................... 2

4.1 Dimensions ................................................................................................................................................................................................. 2

4.2 Designation ................................................................................................................................................................................................ 3

5 Requirements .......................................................................................................................................................................................................... 4

5.1 Material ......................................................................................................................................................................................................... 4

5.2 Manufacture .............................................................................................................................................................................................. 4

5.3 Heat treatment ........................................................................................................................................................................................ 4

5.4 Dimensions ................................................................................................................................................................................................. 4

5.5 Working load limit, WLL ................................................................................................................................................................ 5

5.6 Mechanical properties ...................................................................................................................................................................... 5

5.6.1 General...................................................................................................................................................................................... 5

5.6.2 Test force, F ....................................................................................................................................................................... 6

5.6.3 Elongation at test force ........................................................................................................................................... .... 6

5.6.4 Breaking force, F .......................................................................................................................................................... 6

5.6.5 Deformation ......................................................................................................................................................................... 6

5.7 Surface condition .................................................................................................................................................................................. 6

6 Tests ................................................................................................................................................................................................................................... 6

6.1 Qualification of personnel ............................................................................................................................................................. 6

6.2 Type tests ..................................................................................................................................................................................................... 6

6.2.1 General...................................................................................................................................................................................... 6

6.2.2 Dimension test ................................................................................................................................................................... 6

6.2.3 Surface test............................................................................................................................................................................ 7

6.2.4 Tensile test ............................................................................................................................................................................ 7

6.3 Manufacturing examination ........................................................................................................................................................ 8

6.4 End tests ....................................................................................................................................................................................................... 8

6.4.1 General...................................................................................................................................................................................... 8

6.4.2 Size of lot ...................................................................... ........................................................................................................... 8

6.4.3 Sampling.................................................................................................................................................................................. 8

6.4.4 Dimension test ................................................................................................................................................................... 8

6.4.5 Tensile test ............................................................................................................................................................................ 8

7 Marking .......................................................................................................................................................................................................................... 9

8 Certificates .................................................................................................................................................................................................................. 9

8.1 Type test certificate ............................................................................................................................................................................ 9

8.2 Manufacturer's certificate ..........................................................................................................................................................10

9 Instructions for use ........................................................................................................................................................................................10

10 Environmental issues ...................................................................................................................................................................................10

Annex A (informative) Bases for the calculation...................................................................................................................................11

Annex B (informative) Conversion sling chains/chain components ................................................................................14

Bibliography .............................................................................................................................................................................................................................15

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 4779:2021(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 on 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 the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 111, Round steel link chains, chain slings,

components and accessories, Subcommittee SC 3, Components and accessories.

This second edition cancels and replaces the first edition (ISO 4779:1986), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— limitation of the materials used to stainless steels;
— corresponding adaptation of the alloy elements and heat treatment;
— reduction of the sizes, corresponding to the related nominal chain sizes;

— including detailed formulae base for calculation of dimensions, working load limits and mechanical

requirements in Annex A.

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
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 4779:2021(E)
Chain components for lifting purposes — Forged eye hook
with point and latch — Grade 4, stainless steel, solution
annealed
1 Scope

This document specifies the requirements for forged eye hooks with point and latch of grade 4 from

stainless steel and solution annealed for use preferably as a component in chain slings of welded

construction of grade 4 from stainless steel and solution annealed.

IMPORTANT — For other applications, e.g. steel wire rope slings or textile slings, it is important

that the hook design is checked to ensure its fitness for a safe use.

NOTE 1 The grade for the hook according to this document is taken from the grade of the sling chain according

to ISO 1835. Both (sling chains and hooks) have identical scopes and values for the working load limit, WLL,

according to Table 2 and values for the mechanical requirements according to Table 3. Thus, the direct correlation

of hooks to the sling chain is given by the WLL and especially the code system on the product body itself. The

grade of the hook does not define any values of the tensile strength of the hook material. For further information,

see Annex B.

The range of the nominal diameter, d , of the associated sling chain according to ISO 1835 is from 4 mm

to 22 mm.

Hooks according to this document are for use in the temperature range –100 °C to +400 °C.

These hooks are solution annealed in the finished condition and can therefore be used without

restrictions with regard to the corrosion resistance of the steels according to 5.1.

NOTE 2 The term “eye hook with point and latch” is taken from ISO 1837:2003, Figure 5.

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 1835, Round steel short link chains for lifting purposes — Medium tolerance sling chains — Grade 4,

stainless steel
ISO 1837, Lifting hooks — Nomenclature

ISO 3452-1, Non-destructive testing — Penetrant testing — Part 1: General principles

ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:

Tension/compression testing machines — Calibration and verification of the force-measuring system

ISO 8539, Forged steel lifting components for use with Grade 8 chain

ISO 13385-1, Geometrical product specifications (GPS) — Dimensional measuring equipment — Part 1:

Design and metrological characteristics of callipers

ISO 16143-2, Stainless steels for general purposes — Part 2: Corrosion-resistant semi-finished products,

bars, rods and sections

EN 10228-2, Non-destructive testing of steel forgings - Part 2: Penetrant testing

© ISO 2021 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO 4779:2021(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1837, ISO 8539 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at https:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
nominal size

combination of numerical values without units for designation and ordering purposes, which indicates

the nominal diameter of the associated round steel link chain and the grade of the forged component

EXAMPLE 10-4
3.2
test force
force applied to the hook during the tensile test
4 Dimensions and designation
4.1 Dimensions

The bases for calculation of the values for the dimension limits listed in Table 1 are given in Annex A.

The corresponding dimension letters are shown in Figure 1. The specified values are absolute limits.

The geometry of the hook is not specified in detail. Therefore, Figure 1 specifies only where the

dimension values according to Table 1 are measured.
2 © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 4779:2021(E)
Key
A bar diameter D seat diameter L inner length
B point hight E eye dimension M outer length, see 5.6.3
C throat opening H seat hight W seat width
Figure 1 — Dimensions of hooks

Preferred nominal sizes are given in Table 1, column 1. Other nominal sizes may be used, provided the

corresponding dimensions are calculated in accordance with Annex A.
Table 1 — Dimension limits
Dimensions in millimetres
1 2 3 4 5 6 7 8 9 10
A B C C D E H L W
Nominal
size
max min min max min min max max max
4 - 4 10 12 11 14 15 10 17 62 12
6 - 4 15 17 16 21 22 15 26 93 17
8 - 4 21 23 22 27 30 20 34 124 23
10 - 4 26 29 27 35 38 25 44 157 29
13 - 4 33 38 35 45 49 33 56 202 38
16 - 4 41 47 43 55 60 40 69 248 46
18 - 4 46 52 48 61 67 45 77 277 52
20 - 4 51 58 54 69 75 50 86 311 58
22 - 4 56 64 59 75 82 55 94 340 64
4.2 Designation

The designation of the hook shall be in accordance with the general format given in Figure 2.

© ISO 2021 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO 4779:2021(E)
Figure 2 — General format
5 Requirements
5.1 Material

The steel used shall be austenitic stainless steels with molybdenum and shall be resistant against

intergranular corrosion.

NOTE 1 For example the steel with the ISO name X6CrNiMoTi17-12-2 respectively with the ISO number 4571

316-35-I according to ISO 15510.

NOTE 2 The resistance against pitting corrosion will be increased by alloying with molybdenum.

After solution annealing, intergranular corrosion is unlikely at a service temperature of +400 °C and

with an extra low carbon content of the steel. T
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 4779
ISO/TC 111/SC 3
Chain components for lifting
Secretariat: JISC
purposes — Forged eye hook with
Voting begins on:
2021­05­25 point and latch — Grade 4, stainless
steel, solution annealed
Voting terminates on:
2021­07­20
Éléments de chaînes de levage — Crochets de levage forgés en acier à
bec et à œil — Grade 4, acier inoxydable, recuit d’homogénéisation
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 4779:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 4779:2021(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
CH­1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 4779:2021(E)
Contents Page

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

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

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

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

4 Dimensions and designation ................................................................................................................................................................... 2

4.1 Dimensions ................................................................................................................................................................................................. 2

4.2 Designation ................................................................................................................................................................................................ 3

5 Requirements .......................................................................................................................................................................................................... 4

5.1 Material ......................................................................................................................................................................................................... 4

5.2 Manufacture .............................................................................................................................................................................................. 4

5.3 Heat treatment ........................................................................................................................................................................................ 4

5.4 Dimensions ................................................................................................................................................................................................. 4

5.5 Working load limit, WLL ..................................................................................................................................................................5

5.6 Mechanical properties ...................................................................................................................................................................... 5

5.6.1 General...................................................................................................................................................................................... 5

5.6.2 Test force, F .........................................................................................................................................................................

T 6

5.6.3 Elongation at test force ........................................................................................................................................... .... 6

5.6.4 Breaking force, F .............................................................................................................................................................

B 6

5.6.5 Deformation ......................................................................................................................................................................... 6

5.7 Surface condition .................................................................................................................................................................................. 6

6 Tests ................................................................................................................................................................................................................................... 6

6.1 Qualification of personnel ............................................................................................................................................................. 6

6.2 Type tests ..................................................................................................................................................................................................... 6

6.2.1 General...................................................................................................................................................................................... 6

6.2.2 Dimension test ................................................................................................................................................................... 6

6.2.3 Surface test............................................................................................................................................................................ 7

6.2.4 Tensile test ............................................................................................................................................................................ 7

6.3 Manufacturing examination ........................................................................................................................................................ 8

6.4 End tests ....................................................................................................................................................................................................... 8

6.4.1 General...................................................................................................................................................................................... 8

6.4.2 Size of lot ...................................................................... ........................................................................................................... 8

6.4.3 Sampling.................................................................................................................................................................................. 8

6.4.4 Dimension test ................................................................................................................................................................... 8

6.4.5 Tensile test ............................................................................................................................................................................ 8

7 Marking .......................................................................................................................................................................................................................... 9

8 Certificates .................................................................................................................................................................................................................. 9

8.1 Type test certificate ............................................................................................................................................................................ 9

8.2 Manufacturer's certificate ..........................................................................................................................................................10

9 Instructions for use ........................................................................................................................................................................................10

10 Environmental issues ...................................................................................................................................................................................10

Annex A (informative) Bases for the calculation...................................................................................................................................11

Annex B (informative) Conversion sling chains/chain components ................................................................................14

Bibliography .............................................................................................................................................................................................................................15

© ISO 2021 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 4779:2021(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 non­governmental, 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 on 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 the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 111, Round steel link chains, chain slings,

components and accessories, Subcommittee SC 3, Components and accessories.

This second edition cancels and replaces the first edition (ISO 4779:1986), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— limitation of the materials used to stainless steels;
— corresponding adaptation of the alloy elements and heat treatment;
— reduction of the sizes, corresponding to the related nominal chain sizes;

— including detailed formulae base for calculation of dimensions, working load limits and mechanical

requirements in Annex A.

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
---------------------- Page: 4 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 4779:2021(E)
Chain components for lifting purposes — Forged eye hook
with point and latch — Grade 4, stainless steel, solution
annealed
1 Scope

This document specifies the requirements for forged eye hooks with point and latch of grade 4 from

stainless steel and solution annealed for use preferably as a component in chain slings of welded

construction of grade 4 from stainless steel and solution annealed.

IMPORTANT — For other applications, e.g. steel wire rope slings or textile slings, it is important

that the hook design is checked to ensure its fitness for a safe use.

NOTE 1 The grade for the hook according to this document is taken from the grade of the sling chain according

to ISO 1835. Both (chain slings and hooks) have identical scopes and values for the working load limit, WLL,

according to Table 2 and values for the mechanical requirements according to Table 3. Thus, the direct correlation

of hooks to the sling chain is given by the WLL and especially the code system on the product body itself. The

grade of the hook does not define any values of the tensile strength of the hook material. For further information,

see Annex B.

The range of the nominal diameter, d , of the associated sling chain according to ISO 1835 is from 4 mm

to 22 mm.

Hooks according to this document are for use in the temperature range –100 °C to +400 °C.

These hooks are solution annealed in the finished condition and can therefore be used without

restrictions with regard to the corrosion resistance of the steels according to 5.1.

NOTE 2 The term “eye hook with point and latch” is taken from ISO 1837:2003, Figure 5.

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 1835, Round steel short link chains for lifting purposes — Medium tolerance sling chains — Grade 4,

stainless steel
ISO 1837, Lifting hooks — Nomenclature

ISO 3452­1, Non-destructive testing — Penetrant testing — Part 1: General principles

ISO 7500­1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:

Tension/compression testing machines — Calibration and verification of the force-measuring system

ISO 8539, Forged steel lifting components for use with Grade 8 chain

ISO 13385­1, Geometrical product specifications (GPS) — Dimensional measuring equipment — Part 1:

Design and metrological characteristics of callipers

ISO 16143­2, Stainless steels for general purposes — Part 2: Corrosion-resistant semi-finished products,

bars, rods and sections

EN 10228­2, Non-destructive testing of steel forgings - Part 2: Penetrant testing

© ISO 2021 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO/FDIS 4779:2021(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1837, ISO 8539 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at https:// www .electropedia .org/
— ISO Online browsing platform: available at https:// www .iso .org/ obp
3.1
nominal size

combination of numerical values without units for designation and ordering purposes, which indicates

the nominal diameter of the associated round steel link chain and the grade of the forged component

EXAMPLE 10­4
3.2
test force
force applied to the hook during the tensile test
4 Dimensions and designation
4.1 Dimensions

The bases for calculation of the values for the dimension limits listed in Table 1 are given in Annex A.

The corresponding dimension letters are shown in Figure 1. The specified values are absolute limits.

The geometry of the hook is not specified in detail. Therefore, Figure 1 specifies only where the

dimension values according to Table 1 are measured.
2 © ISO 2021 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/FDIS 4779:2021(E)
Key
A bar diameter D seat diameter L inner length
B point hight E eye dimension M outer length, see 5.6.3
C throat opening H seat hight W seat width
Figure 1 — Dimensions of hooks

Preferred nominal sizes are given in Table 1, column 1. Other nominal sizes may be used, provided the

corresponding dimensions are calculated in accordance with Annex A.
Table 1 — Dimension limits
Dimensions in millimetres
1 2 3 4 5 6 7 8 9 10
A B C C D E H L W
Nominal
size
max min min max min min max max max
4 ­ 4 10 12 11 14 15 10 17 62 12
6 ­ 4 15 17 16 21 22 15 26 93 17
8 ­ 4 21 23 22 27 30 20 34 124 23
10 ­ 4 26 29 27 35 38 25 44 157 29
13 ­ 4 33 38 35 45 49 33 56 202 38
16 ­ 4 41 47 43 55 60 40 69 248 46
18 ­ 4 46 52 48 61 67 45 77 277 52
20 ­ 4 51 58 54 69 75 50 86 311 58
22 ­ 4 56 64 59 75 82 55 94 340 64
4.2 Designation

The designation of the hook shall be in accordance with the general format given in Figure 2.

© ISO 2021 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO/FDIS 4779:2021(E)
Figure 2 — General format
5 Requirements
5.1 Material

The steel used shall be austenitic stainless steels with molybdenum and shall be resistant against

intergranular corrosion.

NOTE 1 For example the steel with the ISO name X6CrNiMoTi17-12-2 respectively with the ISO number 457

...

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