Section 5 Short link chain cables

5.1.1 This Section gives the requirements for electrically welded steel short link chain cable for marine use but excluding those applications covered by the Code for Lifting Appliances in a Marine Environment.

5.1.2 Provision is made for grade M(4), as defined in ISO 1834.

5.2.1 Short link chain cables are to be manufactured at works approved by LR. A list of approved manufacturers for short link chain cable is published separately by LR.

5.2.2 The chain is to be supplied in either the normalised or quenched and tempered condition. Heat treatment is to be carried out prior to proof and breaking load testing.

5.2.3 The chain may be galvanised using a hot dipping process provided that this is carried out prior to proof and breaking load testing. If galvanised, it is recommended that the thickness of the zinc coating be not less than 70 microns.

5.2.4 Unless otherwise agreed, the finished chain is to be free from coatings other than zinc.

5.3.1 Bars for the manufacture of short link chain cable are to be made and tested in accordance with the appropriate requirements of Ch 3, 1 General requirements and to the requirements of an International or acceptable National Standard.

5.3.2 The bars are to be made at a works approved by LR.

5.3.3 The steel is to be fully killed and fine grain treated.

5.3.4 The steel is to have mechanical properties which will allow the chain to meet the mechanical test requirements of Ch 10, 5.4 Testing and inspection of chain cables 5.4.7 and Table 10.5.1 Mechanical test requirements for short link chain cables.

5.4.1 All chain cable of 12,5 mm diameter and above, and all steering chains irrespective of diameter, are to be tested in the presence of a Surveyor at a proving establishment recognised by LR. A list of recognised proving establishments is published by LR. In addition to the requirements stated in this Chapter, attention is to be given to any relevant statutory requirements of the National Authority of the country in which the ship or other marine structure is to be registered.

5.4.2 For chain of diameter less than 12,5 mm, other than steering chains, the manufacturer's tests will be acceptable.

5.4.3 After completion of all manufacturing processes, including heat treatment and galvanising, the whole of the chain is to be subjected to the appropriate proof load specified in Table 10.5.1 Mechanical test requirements for short link chain cables.

5.4.4 The whole of the chain is to be inspected after the proof load test and is to be free from significant defects.

5.4.5 At least one sample, consisting of seven or more links, is to be selected by the Surveyor from each 200 m or less of chain for breaking load tests. Two additional links may be required for engagement in the jaws of the testing machine. These extra links are not to be taken into account in determining the total elongation, see Ch 10, 5.4 Testing and inspection of chain cables 5.4.7.

5.4.6 The breaking load is to comply with the appropriate requirements of Table 10.5.1 Mechanical test requirements for short link chain cables.

5.4.7 The total elongation of the breaking load sample at fracture, expressed as a percentage of the original inside length of the sample after proof loading, is to be not less than 20 per cent.

5.5.1 The form and proportions of links are to be in accordance with Figure 10.5.1 Form and proportions of links.

Figure 10.5.1 Form and proportions of links

5.5.2 Manufacturing tolerances are to be within the following limits:

Nominal diameter, d n	± 5%
Pitch of chain, p 1	± 3%
Length measured over 11 links	± 2%
Inside width, w 1	1,35 d n minimum
Outside width, w	3,6 d n maximum

The tolerances are to apply after galvanising. All measurements are to be taken after proof testing.

5.6.1 All lengths of cable are to be stamped with the following identification marks:

1. Inspector's mark and date.

2. Reference mark or number of certificate.

3. Manufacturer's mark or name.

4. Chain cable quality mark, M, is to be stamped on at least each twentieth link or at intervals of one metre, whichever is the lesser distance.

5.6.2 Where the inspection is performed under LR`s supervision, the inspector's mark and date are to be replaced by LR and the abbreviated name of LR's local office issuing the certificate.

5.7.1 The manufacturer is to supply the Surveyor with a certificate stating compliance with an appropriate ISO standard, and also, in the event of the requirements of Ch 10, 5.4 Testing and inspection of chain cables being undertaken other than in the presence of the Surveyor, stating that the test and inspection requirements have been complied with at a recognised proving establishment.

5.7.2 Each test certificate is to include the following particulars:

1. the quality and description of chain,

2. identification mark,

3. nominal size of chain,

4. proof load,

5. breaking load,

6. total elongation at fracture,

7. where appropriate, the name of the proving establishment.