Equipment for Mooring and Anchoring
Chemical composition of butt welded and forged chain cable
Grade Chemical composition %
C max. Si Mn P max. S max. Al N max. Cr max. Ca max. Na max. Nr max. V max. Mo max.
U1 0,20 0,15-0,35 0,40 min. 0,40 0,34 - - - - - - - -
U2 0,24 0,15-0,55 0,60 max. 0,035 0,035 0,02 min. see Note 1 - - - - - - -
U3 0,33 0,15-0,35 0,90 max. 0,04 0,04 0,065 max. see Note 2 0,015 0,25 0,35 0,05 see Note 2 0,40 0,10 see Note 2 0,08
NOTES:
1. Aluminium may be partly replaced by other grain refining elements.
2. To obtain fine grain steel, at least one of these grain refining elements must be present in sufficient amount
Heat treatment of completed chain cables.
Grade Condition of supply
U1 As welded or normalised
U2 Normalised, or normalised and tempered, or quenched and tempered (see note)
U3 Normalised, or normalised and tempered, or quenched and tempered
NOTES:
Grade U2 chain may be supplied in the 'as-welded' condition provided that this is specially approved and that the number of breaking tests complies with the requirements
Welding of studs
a) Where studs are welded into the links this is to be completed before the chain cable is heat treated.

b) The stud ends must be a good fit inside the link and the weld is to be confined to the stud end opposite the flash-butt weld. The full periphery of the stud end is to be welded. If however, it can be demonstrated to the Surveyor that the quality of welding is of a high standard then partial peripheral welding may be accepted provided that welds are made only at the sides of the stud and that each run extends continuously for at least 25per cent of the stud periphery.

c) The welds are to be made by qualified welders using an approved procedure and consumables approved to Grade 3 and low hydrogen.

d) The welds are to be of good quality and free from defects lable to impair the proper use of the chain. Undercuts, end craters and similar defects shall, where necessary be ground off.

e) At least one stud weld within each length of cable is to be inspected using dye penetrant testing after the chain has been proof loaded , a crack is found, the stud welds in the adjoining links are to be inspected; if a crack is found in either link, all the stud welds in that length are to be inspected using dye penetrant 		Heat treatment of completed chain cables.
a) The completed chain cable is to be heat treated in accordance with Table - 2 for the appropriate grade of cable.

b) Special consideration will be given ot the heat treatment of certain types of drop forged chain cable.

c) In all cases, heat treatment is to be carried cut prior to the proof loading and breaking tests.

d) All test samples are to be heat treated with, and in the same way as, the chain cables they represent.

Testing of completed chain cables
a) All chain cable is to be subjected to a Proof Load test and a Breaking Load test in addition Grade U3 and grade U2 where applicable are to be subjected to mechanical tests.

b) All chain cable is to be tested in the presence of a Surveyor, at a proving establishment recognised by LR, A list of recognised proving establishments is published separately by LR. In addition to the requirements stated in this Chapter, attention must be given to any relevant statutory requirements of the National Authority of the country in which the ship is to be registered.

Proof load tests
a) Each length of chain cable is to be subjected to a proof loading test in an approved testing machine and is to withstand the load for the appropriate grade and size of cable.

b) For test purpose the lable is to be clean and free from paint and anti-corrosive coatings.

c) On completion of the test, each link is to be examined and is to be free from significant defects.

d) Should any link be found to be defective it is to be replaced by an approved connecting link (joining shackles or substitute link as detailed). The chain is then to be subjected to a repeat of the proof load test followed by re-examination.