Section 10-3 Offshore Chains and Chain Accessories

1021. Application

1. The requirements in this Section apply to the tests and inspection for the approval of manufacturing process of the offshore chain and chain accessories (hereinafter called chains and chain accessories) specified in Pt 4, Ch 8, 401. 2 of the Guidance.

2. Chains and chain accessories are to comply with the additional requirements, which are 1001 for offshore chains and 1011 for offshore chain accessories, other than the above 1.

1022. Materials

1. Kind of materials, mechanical properties used in chains and chain accessories are to comply with

Pt 2, Annex 2-9 of the Guidance.

2. Manufacturers propriety specifications for R4S and R5 may vary subject to design conditions and the acceptance of the Society.

3. Each Grade is to be individually approved. Approval for a higher grade does not constitute appro- val of a lower grade.

1023. Chain Approval of manufacturing process

1. Chains are to be manufactured only by works approved by the Society.

2. Data to be submitted

(1) Kind of chains

(2) Manufacturing process

(3) Materials

(4) Heat treating method (including furnace types, controlling and recording of temperature and chain speed and allowable limits, quenching bath and agitation, cooling method after exit)

(5) Diameter of test chain, maximum chain diameter

(6) In addition to the above, the following reference data are to be submitted for approval and re- view to the Society.

(A) Bar heating and bending including method, temperatures, temperature control and recording

(B) Proof and break loading including method, method of measurement, and recording

(C) Manufacturer’'s surface quality requirement of mooring components

(D) Manufacturing process, manufacturing facilities and Welding machines description according to 1001. (6) (A) (a) and (b)

(E) Working standards

(a)

Inspection organization chart

(b) Contents of inspection at the reception of raw materials

(c)

Bar cutting, heating and bending including method, temperatures, temperature control and recording

(d) Working standards applicable to each size of chain link for flash butt welding (welding current, force, time, flash allowance, upsetting allowance, preheating temperature and pe-

riod, etc.)

(e)

(f)

Flash removal including method and inspection Stud manufacturing process and dimensions

(g) Stud insertion method for stud link chain

(h) Non-destructive examination procedures

(i)

Details of product inspection

3. Calibration of furnaces

Calibration of furnaces shall be verified by measurement and recording of a calibration test piece with dimensions equivalent to the maximum size of link manufactured. Thermocouples are to be placed both on the surface and in a drilled hole located to the mid thickness position of the cali- bration block.

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4. Approval test

(1) Approval test

The approval test is to be carried out on each chain under application for each manufacturing factory. The contents of approval test are to be as indicated in Table 2.10.3 and the test is to be carried out in the presence of the Surveyor unless otherwise specified.

(2) Test chains

The link and test specimens used in the approval test are to be taken from the test chains in the presence of the Surveyor.

5. Changes in the approval content

When major changes are intended to be made in the manufacturing process already approved, the application procedure required for a new approval application is to be taken. The major changes in- clude the items given below where, however, the witness of the approval test by the Surveyor may be dispensed with, or reduction in the approval test items may be accepted for the manufacturer whose product quality control standards and inspection standards are considered appropriate. In this case, however, submission of the results of tests on material properties and related data is required.

(1) Increase in the maximum diameter of chain to be manufactured

(2) Change in casting procedure

(3) Changes in heat treatments (quenching, annealing, tempering, etc.)

(4) New installation of welding machine

(5) New installation of furnace for heat treatment

(6) Other changes for which approval test is considered necessary

1024. Approval of quality system at chain and accessory manufacturers

Chain and accessory manufacturers are to have a documented and effective quality system approved by Ch 2, 104. 2. The quality system is to be additionally submitted during witnessing of tests by Surveyor in order to approve the chain and chain accessories.

1025. Approval of forges and foundries for chain accessories

1. Forges and foundries intending to supply finished or semi-finished accessories are to be approved by the Society. The approval is to be limited to a nominated supplier of forged or cast material. If an accessory manufacturer wishes to use material from a number of suppliers, a separate approval must be carried out for each supplier.

2. The approval will

normally be limited to the type of accessory and

the IACS designated mooring

grade of material up to the maximum diameter or thickness equal to that of the completed ac-

cessory used for

qualification. Qualification of accessory pins to

maximum diameters is also

required. Individual accessories of complex geometries will be subject

to the Society requirements.

3. Forges and foundries are to provide evidence that the manufacturing process produces material that is resistant to strain ageing, temper embrittlement and for R4S and R5 grades, hydrogen embrittlement. A heat treatment sensitivity study simulating accessory production conditions shall be applied in order to verify mechanical properties and establish limits for temperature and time combinations. (Cooling after tempering shall be appropriate to avoid temper embrittlement). All test details and results are to be submitted to the Classification society.

4. For initial approval, Three CTOD tests are to be tested with a standard 2 × 1 single edge notched bend specimen in accordance with a recognized international standard such as BS 7448 Parts 1 &

2. The specimen location is as shown in Table 2.10.3 notes 7. The minimum test piece size shall be 50 × 25 mm for chain diameters less than 120 mm, and 80 × 40 mm for diameters 120 mm and

above. The tests are to be taken at minus 20 ℃ and the results are to be submitted to the Society.

5. Calibration of furnaces shall be verified by measurement and recording of a calibration test piece with dimensions equivalent to the maximum size of link manufactured. Thermocouples are to be placed both on the surface and in a drilled hole located to the mid thickness position of the cali- bration block.

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Table 2.10.3 Approval Test Items and Acceptance Criteria for Offshore Chains

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Table 2.10.3 Approval Test Items and Acceptance Criteria for Offshore Chains(continue)

Test chains for approval test

6. Temperatures of impact test are to be in accordance with following tables.

7. CTOD test required for offshore mooring chain is to comply with the followings

For initial approval, CTOD tests are to be tested in accordance with a recognized international standard such as BS 7448 Parts 1 & 2. The CTOD test piece is to be a standard 2 × 1 single edge notched bend piece, test location as shown in Figure 1. The minimum test piece size shall be 50 × 25 mm for chain diameters less than 120 mm, and 80 × 40 mm for diameters 120 mm and above. CTOD specimens are to be taken from both the side of the link containing the weld and from the opposite side. Three links are to be selected for testing, a

total of six CTOD specimens. The tests are to be taken at minus 20 ℃ and the acceptance criteria is to be

the values and more than the values indicated below:

BM : Base metal WM : Weld metal

8. For R4S and R5 chain, prior to approval, the manufacturer is to have undertaken experimental tests or have relevant supporting data to develop the chain material. The tests and data may include fatigue tests, hot ductil- ity tests (no internal flaws are to develop whilst bending in the link forming temperature range), welding pa- rameter research, heat treatment study, strain age resistance, temper embrittlement study, stress corrosion crack- ing (SCC) data and hydrogen embrittlement (HE) study, using slow strain test pieces in hydrated environments. Reports indicating the results of experimental tests are to be submitted.

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6. Approval test

(1) Approval test

The approval test is to be carried out on each item of chain accessories under application for each manufacturing factory. The details of approval test are to be as indicated in Table 2.10.4 and the test is to be carried out in the presence of the Surveyor unless otherwise specified.

(2) Test chain accessories

The test specimens used in the approval test are to be taken from the test chain accessories un- der application in the presence of the Surveyor.

7. Changes in the manufacturing process

Where major changes significantly affecting the manufacturing process already approved have been made, the requirements in 1023. 5 are to apply.

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Table 2.10.4 Approval Test Items and Acceptance Criteria for Offshore Chains Accessories

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