ISO/FDIS 4779

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
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ISO/FDIS 4779:2021(E)
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© ISO 2021

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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 .........................................................................................................................................................................

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

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

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

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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

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

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

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

Any feedback or questions on this document should be directed to the user’s national standards body. A

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

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

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,

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

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,

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

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

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

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

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

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

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

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

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

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

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