Round steel short link chains for lifting purposes -- Chain slings of welded construction -- Grade 8

This document specifies the requirements, methods of rating and testing of single, double, three and four leg welded chain slings of grade 8 using components such as sling chains according to ISO 3076 together with links according to ISO 16798, hooks according to ISO 7597 and forged components according to ISO 8539. NOTE 1 For special lifting purposes not covered by this document, additionally intermediate links can be used, for example to connect components to each other having different working load limit. The range of nominal diameter, dn, covered by this document is from 4 mm to 45 mm. Chain slings according to this document are for use in the temperature range ?40 °C to +400 °C according to ISO 3056. NOTE 2 Concerning the use and maintenance of chain slings of grade 8, see ISO 3056. Chain slings according to this document comply with the general conditions of acceptance of ISO 1834 and are used for symmetrically distributed loads only. NOTE 3 For rating of chain slings with asymmetrically distributed loads, see ISO 3056. This document does not apply to mechanically joined chain slings. NOTE 4 For mechanically joined chain slings, see ISO 7593.

Chaînes de levage en acier de section ronde à maillons courts -- Elingues en chaînes assemblées par soudure -- Classe de qualité 8

General Information

Status
Published
Publication Date
13-Jun-2019
Current Stage
6060 - International Standard published
Start Date
22-May-2019
Completion Date
14-Jun-2019
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INTERNATIONAL ISO
STANDARD 4778
Second edition
2019-06
Round steel short link chains for
lifting purposes — Chain slings of
welded construction — Grade 8
Chaînes de levage en acier de section ronde à maillons courts —
Elingues en chaînes assemblées par soudure — Classe de qualité 8
Reference number
ISO 4778:2019(E)
ISO 2019
---------------------- Page: 1 ----------------------
ISO 4778:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

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
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Phone: +41 22 749 01 11
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Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 4778:2019(E)
Contents Page

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

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Requirements .......................................................................................................................................................................................................... 3

4.1 Chain sling ................................................................................................................................................................................................... 3

4.2 Components ............................................................................................................................................................................................... 4

4.2.1 Chain legs ............................................................................................................................................................................... 4

4.2.2 Master links .......................................................................................................................................................................... 4

4.2.3 Intermediate master links, joining links and end links .................................................................. 4

4.2.4 Hooks ......................................................................................................................................................................................... 5

4.2.5 Other forged components ........................................................................................................................................ 5

4.3 Working load limit (WLL) .............................................................................................................................................................. 5

4.4 Mechanical requirements .............................................................................................................................................................. 6

4.4.1 General...................................................................................................................................................................................... 6

4.4.2 Single leg chain sling..................................................................................................................................................... 7

4.4.3 Double leg chain sling .................................................................................................................................................. 8

4.4.4 Three and four leg chain sling .............................................................................................................................. 9

5 Marking .......................................................................................................................................................................................................................10

5.1 General ........................................................................................................................................................................................................10

5.2 Single leg chain sling .......................................................................................................................................................................10

5.3 Double leg chain sling ....................................................................................................................................................................11

5.4 Three and four leg chain sling.................................................................................................................................................11

6 Manufacturer's certificate .......................................................................................................................................................................11

7 Examples of chain slings ............................................................................................................................................................................12

Annex A (informative) Bases for calculation .............................................................................................................................................16

Annex B (informative) Correlations, grade 8 ............................................................................................................................................20

Annex C (informative) Compatibility of chain slings to shank hooks ..............................................................................22

Annex D (informative) Information for the calculation of the nominal diameter of links ........................24

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

© ISO 2019 – All rights reserved iii
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ISO 4778:2019(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 111, Round steel link chains, chain slings,

components and accessories, Subcommittee SC 1, Chains and chain slings.

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.

This second edition cancels and replaces the first edition (ISO 4778:1981), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— omission of grades 4 and 6;
— increased range of nominal diameters from 4 mm to 45 mm;

— modernization of the document structure and layout, following the structure already implemented

in the latest publications of ISO/TC 111/SC 1.
iv © ISO 2019 – All rights reserved
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INTERNATIONAL STANDARD ISO 4778:2019(E)
Round steel short link chains for lifting purposes — Chain
slings of welded construction — Grade 8
1 Scope

This document specifies the requirements, methods of rating and testing of single, double, three and

four leg welded chain slings of grade 8 using components such as sling chains according to ISO 3076

together with links according to ISO 16798, hooks according to ISO 7597 and forged components

according to ISO 8539.

NOTE 1 For special lifting purposes not covered by this document, additionally intermediate links can be

used, for example to connect components to each other having different working load limit.

The range of nominal diameter, d , covered by this document is from 4 mm to 45 mm.

Chain slings according to this document are for use in the temperature range –40 °C to +400 °C

according to ISO 3056.

NOTE 2 Concerning the use and maintenance of chain slings of grade 8, see ISO 3056.

Chain slings according to this document comply with the general conditions of acceptance of ISO 1834

and are used for symmetrically distributed loads only.

NOTE 3 For rating of chain slings with asymmetrically distributed loads, see ISO 3056.

This document does not apply to mechanically joined chain slings.
NOTE 4 For mechanically joined chain slings, see ISO 7593.
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 3076, Round steel short link chains for general lifting purposes — Medium tolerance sling chains for

chain slings — Grade 8
ISO 7597, Forged steel lifting hooks with latch, grade 8
ISO 8539, Forged steel lifting components for use with Grade 8 chain
ISO 16798, Links of Grade 8 for use with slings
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
© ISO 2019 – All rights reserved 1
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ISO 4778:2019(E)
3.1
nominal diameter
diameter of the sling chain used as a chain leg in a chain sling

Note 1 to entry: The nominal diameter of the chain slings is the nominal diameter of the sling chain used.

3.2
chain sling

assembly consisting of chain leg or chain legs joined to upper and lower terminal components for

attaching loads to be lifted to the hook of a crane or other lifting machine
Note 1 to entry: See Figures 5 to 8.
3.3
chain leg

component of a chain sling, consisting of a fixed number of identical chain links

3.4
upper terminal component

link or other device fitted through a joining link or links to the end of a chain leg or chain legs by means

of which it is attached to the hook of a crane or other lifting machine
Note 1 to entry: See Figures 5 to 8.
3.5
master link
parallel-sided link forming the upper terminal component
3.6
master link assembly
assembly consisting of a master link together with two intermediate master links
Note 1 to entry: See Figure 1.
Key
1 master link
2 intermediate master link
Figure 1 — Master link assembly
3.7
intermediate master link
parallel-sided link used to connect one or two chain legs to a master link
Note 1 to entry: See Figures 5 to 8.
2 © ISO 2019 – All rights reserved
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ISO 4778:2019(E)
3.8
joining link

parallel-sided link fitted to connect the chain leg to an upper or lower terminal component

Note 1 to entry: See Figures 5 to 8.
3.9
lower terminal component

end link, hook or other device fitted through a joining link to the end of a chain leg opposite to the upper

terminal component
Note 1 to entry: See Figures 5 to 8.
3.10
end link
parallel-sided link forming the lower terminal component
3.11
nominal reach

effective length of a chain leg, measured from the inside of the lower terminal component to the inside

of the upper terminal component
Note 1 to entry: See Figures 5 to 8.
3.12
working load limit
WLL
maximum mass which a chain sling is authorized to sustain in service
3.13
manufacturing proof force
MPF
force applied during manufacture to test sections of the chain sling
3.14
breaking force

maximum force which the test sections of the chain withstands during the course of a static tensile test

to destruction
3.15
inclination angle

angle between the chain leg and the vertical, separated to the range from 0° up to and including 45° and

the range from 45° up to including 60°
3.16
test section
individual section of the chain sling to be tested
4 Requirements
4.1 Chain sling

No one but the chain manufacturer, its licensee or an organization authorized by an appropriate

authority is allowed to weld, heat treat and test chain slings covered by this document.

Where components of chain slings need to be altered or repaired, this shall be undertaken only by the

chain manufacturer, his licensee, or a manufacturer authorized by an appropriate authority.

© ISO 2019 – All rights reserved 3
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ISO 4778:2019(E)

Every component shall have a working load limit not less than that of a single chain leg to which it is

connected.

When constructing the chain sling, a tolerance of chain links is permissible on the nominal reach.

After proof loading, the difference between the longest and shortest chain legs of a multi-leg chain sling,

when measured under a tension of 20 % of the working load limit, shall not exceed 10 mm for chain legs

up to 2 m in length. For chain slings in excess of 2 m, the difference between the longest and shortest

chain legs may be increased by 5 mm/m.
4.2 Components
4.2.1 Chain legs
Chain legs shall comply with ISO 3076.
4.2.2 Master links
Master links shall comply with ISO 16798.
The inside dimension and the cross-section of the material shall be such that:

a) the master link fits to a shank hook (e.g. according to ISO 17440; see Annex C);

b) the inside width of the master link is not less than 1,2 times the maximum width (see dimension b

in ISO 17440:2014, Figure A.1 and Table A.1) of the shank hook;

c) for chain slings with hooks as lower terminal components the inside dimensions and the cross-

section are such as to allow the lower terminal component when not loaded to be hooked back into

the master link while it is on the shank hook.

Master links may be of round or other suitable cross-section. But the cross-section of the material shall

be chosen so that:

a) after proof loading (see 4.4.1) the master link does not show any significant permanent deformation;

b) the minimum total ultimate elongation at fracture is at least that of the sling chain.

NOTE A method of calculating the cross-section of master links is given in Annex D.

IMPORTANT — Egg- or pear-shaped links shall be designed to exclude unintended inverting.

4.2.3 Intermediate master links, joining links and end links

Intermediate master links, joining links and end links shall comply with ISO 16798 except for the

clauses relating to link dimensions.

The internal dimensions of intermediate master links, joining links and end links shall be such that

they ensure free articulation of the links.
The cross-section of the material shall be such that:

a) after proof loading (see 4.4.1) the intermediate master links, joining links and end links do not show

any significant permanent deformation;

b) the minimum total ultimate elongation at fracture is at least that of the sling chain.

IMPORTANT — Egg- or pear-shaped links shall be designed to exclude unintended inverting.

4 © ISO 2019 – All rights reserved
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ISO 4778:2019(E)
4.2.4 Hooks

Forged steel lifting hooks with latch shall comply with ISO 7597 and shall be compatible with the sling

chains according to ISO 3076.
Hooks not otherwise covered by this document shall comply with ISO 8539.
4.2.5 Other forged components

Other forged steel components, e.g. shackles, shall comply with ISO 8539 and shall be compatible with

the sling chains according to ISO 3076.
4.3 Working load limit (WLL)

Table 1 gives values for the working load limit (WLL) calculated on the bases given in Annex A.

Table 1 — Working load limit (WLL)
Values in tonnes
1 2 3 4 5 6 7
Nominal Single leg Double leg Three- and four-leg
diame-
ter
d Intermediate
master
link
β = 0° 0° < β ≤ 45° 45° < β ≤ 60° β = 37,5° 0° < β ≤ 45° 45° < β ≤ 60°
WLL1/0° WLL2/45° WLL2/60° WLL3/37,5° WLL4/45° WLL4/60°
Load factor Load factor Load factor Load factor Load factor Load factor
1,0 1,41 1,0 1,6 2,12 1,5

[= 1 × cos 0°] [= 2 × cos 45°] [= 2 × cos 60°] [= 2 × cos 37,5°] [= 3 × cos 45°] [= 3 × cos 60°]

4 0,50 0,71 0,50 0,80 1,06 0,75
6 1,12 1,60 1,12 1,80 2,36 1,70
7 1,50 2,12 1,50 2,36 3,15 2,24
8 2,00 2,80 2,00 3,15 4,25 3,00
10 3,15 4,50 3,15 5,00 6,70 4,75
13 5,30 7,50 5,30 8,50 11,2 8,00
16 8,00 11,2 8,00 12,5 17,0 11,8
18 10,0 14,0 10,0 16,0 21,2 15,0
19 11,2 16,0 11,2 18,0 23,6 17,0
20 12,5 18,0 12,5 20,0 26,5 19,0
22 15,0 21,2 15,0 23,6 31,5 22,4
26 21,2 30,0 21,2 33,5 45,0 31,5
28 25,0 35,5 25,0 37,5 53,0 37,5
32 31,5 45,0 31,5 50,0 67,0 47,5
© ISO 2019 – All rights reserved 5
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ISO 4778:2019(E)
Table 1 (continued)
1 2 3 4 5 6 7
Nominal Single leg Double leg Three- and four-leg
diame-
ter
d Intermediate
master
link
β = 0° 0° < β ≤ 45° 45° < β ≤ 60° β = 37,5° 0° < β ≤ 45° 45° < β ≤ 60°
WLL1/0° WLL2/45° WLL2/60° WLL3/37,5° WLL4/45° WLL4/60°
Load factor Load factor Load factor Load factor Load f
...

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