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DNV-OS-E302 Offshore Mooring Chain
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Ch.2
SECTION 2
Mooring Chain Cables and AccessoriesCh.2 Sec.2
A. General Requirements
Ch.2 Sec.2
A 100 Scope
Ch.2 Sec.2 A
101 Sub-section A specifies the general requirements for mooring
chain and accessories in grade R3, R3S, R4, R4S and R5. The materials
used shall comply with the requirements in Sec.1.Ch.2 Sec.2
A 200 Inspection
Ch.2 Sec.2 A
201 Chain and accessories are subject to visual inspection, non-destructive
testing (NDT) and measurements of dimensions as detailed in B and
C. The manufacturer shall prepare written procedures for NDT. NDT
personnel shall be qualified and certified according to ISO 9712,
EN 473, SNT-TC-1A or equivalent. NDT operators shall be qualified
to at least level I.Ch.2 Sec.2
A 300 Repair
Ch.2 Sec.2 A
301 Defects may be removed by grinding as specified in B and C.
The resulting grooves shall have a bottom radius of approximately
three times the depth and shall be blended into the surrounding
surface to avoid any sharp contours. Complete elimination of the
defective material shall be verified by suitable NDT. Ch.2 Sec.2
A 400 Identification
Ch.2 Sec.2 A
401 Identification marks shall be legible and, as far as possible,
permanent throughout the expected service life of the chains and
accessories.Ch.2 Sec.2
A 500 Records
Ch.2 Sec.2 A
501 The manufacturer shall maintain traceable records of the following
and present them to the purchaser on request:- materials, as detailed in Sec.1
- manufacture and heat treatment of chain and accessories
- proof load testing
- breaking load testing
- mechanical testing
- measurement of dimensions
- inspection
- repair.
Ch.2 Sec.2 A
502 The manufacturer is responsible for storing, in a safe and retrievable
manner, all records for at least ten years.Ch.2 Sec.2
B. Mooring Chain
Ch.2 Sec.2
B 100 Scope
Ch.2 Sec.2 B
101 These requirements are supplementary to A and apply to stud
link and stud less mooring chain. Ch.2 Sec.2
B 200 Design
Ch.2 Sec.2 B
201 For stud link mooring chain, the form and proportion of links
shall be in accordance with ISO 1704. The stud shall be designed
to give an impression radius not less than 4 mm and a depth of impression
between 2 and 6% of the nominal chain diameter.
Ch.2 Sec.2 B
202 For stud less mooring chain, the nominal outside length shall
be six times nominal diameter and the nominal outside width shall
be 3.35 times nominal diameter unless otherwise agreed between manufacturer
and purchaser. Links having different proportions must be able to
accommodate adjacent links and connectors.Ch.2 Sec.2
B 300 Manufacture
Ch.2 Sec.2 B
301 Mooring chains shall be manufactured in continuous lengths
by flash butt welding.
Ch.2 Sec.2 B
302 Blanks for links shall be heated by electric resistance or in
a furnace. For electric resistance heating, the heating phase shall
be controlled by an optical heat sensor. For furnace heating, the
temperature shall be controlled and continuously recorded using
thermocouples in close proximity to the bars. In both cases, the
controls shall be checked at least once every eight hours and records
made.
Ch.2 Sec.2 B
303 The following welding parameters shall be controlled during
welding of each link:
| — | platen motion |
| — | current as a function of time |
| — | hydraulic upset pressure. |
The controls shall be checked at least every four hours and records
made.
Ch.2 Sec.2 B
304 Excess flash weld material shall be removed. A clean fusion
zone, including the zone where the stud is pressed into the link,
shall be maintained. The trimming knives used for flash removal
shall be systematically and periodically controlled in order to
monitor the degree of deterioration. The knives shall be changed
out at regular intervals as specified in the applicable work procedure.
Ch.2 Sec.2
B 400 Welding of studs
Ch.2 Sec.2 B
401 Studs may be welded for grade R3 and R3S chains. Welding shall
be completed before the chain is heat treated. Welding of studs
in grade R4, R4S and R5 chain is not permitted.
Ch.2 Sec.2 B
402 Stud welds shall be made by qualified operators or welders
using qualified procedures and low-hydrogen processes or consumables.
The stud ends must be a good fit inside the link and the weld shall
be confined to the stud end opposite the flash butt weld. The full
periphery of the stud end shall be welded. The size of the stud
welds shall be according to API Specification 2F.Ch.2 Sec.2
B 500 Heat treatment
Ch.2 Sec.2 B
501 Mooring chains shall be heat treated in continuous furnaces.
Batch heat treatment is not permitted except for short lengths of
chain such as adaptor pieces and chafe chains.
Ch.2 Sec.2 B
502 Grade R3 and R3S shall be supplied in the normalised, normalised
and tempered, or quenched and tempered condition. Grade R4, R4S
and R5 shall be supplied in the quenched and tempered condition.
Tempering temperatures shall not be less than 570°C and cooling
after tempering shall be in water.
Ch.2 Sec.2 B
503 The temperature uniformity of furnaces shall be checked at
least annually during normal furnace operations and whenever production
changes to a chain diameter that differs by more than 15% from
the previous check. Furnaces shall be checked by a monitoring link
similar to the production links and instrumented with two thermocouples;
one attached to the surface of the straight portion and one imbedded
in the centre of the straight portion. The strip chart recording
shall indicate that the surface temperature never exceeds the maximum
specified after the core has reached the minimum temperature specified. The
combinations of temperatures and soaking times shall be sufficient
to accomplish the heat treatment objectives.
Ch.2 Sec.2 B
504 Furnaces shall be fully stabilised before the production chain
enters. The leading and trailing ends of the production chain shall
be provided with sufficient scrap chain to ensure uniform conditions
during heat treatment.
Ch.2 Sec.2 B
505 Furnace zone temperatures, chain speed and quenching water
temperature shall be controlled and continuously recorded. The records
shall identify each chain length treated.
Ch.2 Sec.2 B
506 To further control heat treatment of grade R4, R4S and R5
chains exceeding 700 meters length, hardness surveys along the length
shall be made every 100 meters provided every heat of steel is represented.
Hardness tests shall also be made on each link subjected to mechanical
tests. Indentations shall be made at the same place on each link,
preferably on the straight portion, after suitable surface preparation.
A minimum of five indentations should be made on each link to obtain
an average hardness value. Each link not tested for mechanical properties
shall have an average value within 15% of the link(s) from
the same heat that has been satisfactorily tested for mechanical
properties. If the results do not comply, the link with the largest
deviation shall be cut out and subjected to mechanical testing.
No further action is required if the mechanical properties are met.
Hardness surveys shall be recorded.Ch.2 Sec.2
B 600 Proof load testing
Ch.2 Sec.2 B
601 Each length of chain shall be proof load tested in the condition
of supply and shall withstand the proof load specified in Table C1 without fracture. The
applied load may exceed the specified minimum load by up to 15% in
order to fasten studs and or to adjust dimensions.
Ch.2 Sec.2 B
602 In the event of a test failure, two additional breaking load
tests shall be made; one from each side of the failed link. The
length shall be considered acceptable if both additional tests meet
the requirement and if it has been determined by examination that
the probable cause of failure is not present in any of the remaining
links.Ch.2 Sec.2
B 700 Breaking load testing
Ch.2 Sec.2 B
701 Samples of the chain shall be subjected to breaking load testing
in the condition of supply. The frequency of sampling shall be in
accordance with Table C2 provided
that every heat of steel is represented. End links and enlarged
links heat treated with the chain need not be tested provided that
common links from the same heat of steel are tested.
Ch.2 Sec.2 B
702 A sample consists of at least three links, except that for chain
with nominal diameter 100 mm or above, the sample may consist of
one link provided that terminations of similar size and geometry
providing a good fit are used.
Ch.2 Sec.2 B
703 Sample links for testing shall be made as part of the chain
cable. They may be removed prior to heat treatment provided that:| — | each sample is properly identified
with the chain represented, and |
| — | each sample is securely attached to and heat treated
with the chain represented. |
Where multiple samples are needed to represent a continuous length,
these shall be attached to both ends of the chain. Where sub-lengths
of chain are temporarily joined for continuous passage through the
furnace, samples shall also be attached in-between if the number
permits.
Ch.2 Sec.2 B
704 Each sample shall withstand the breaking load specified in
Table C1. It shall be considered acceptable if the samples show
no sign of fracture after application of the minimum specified load
for 30 seconds. If the capacity of the manufacturer's testing
machine is insufficient, the testing shall be carried out at another
place recognised by the purchaser.
Ch.2 Sec.2 B
705 In the event of a test failure, two further breaking load tests
shall be made. The sampling length shall be considered acceptable
if both additional tests meet the requirement and if it has been
determined by examination that the probable cause of failure is
not present in any of the remaining links.
Ch.2 Sec.2
B 800 Mechanical testing
Ch.2 Sec.2 B
801 Samples of the chain shall be subjected to mechanical testing
after proof load testing, except as provided in 802. The frequency
of sampling shall be in accordance with Table
C2 provided that every heat of steel is represented. End
links and enlarged links heat treated with the chain need not be
tested provided that common links from the same heat of steel are tested.
Ch.2 Sec.2 B
802 Prior proof load testing of sample links may be omitted provided
it is documented that the properties, when determined after proof
load testing, generally equal or exceed those of links without prior
proof load testing. Test results from at least three heats of a
particular grade shall be provided for this purpose.
Ch.2 Sec.2 B
803 A sample consists of at least one link. Sample links for testing
shall be made as part of the chain cable. They may be removed prior
to heat treatment provided that:| — | each sample is properly identified with the chain
represented, and |
| — | each sample is securely attached to and heat treated
with the chain represented. |
Where multiple samples are needed to represent a continuous length,
these shall be attached to both ends of the chain. Where sub-lengths
of chain are temporarily joined for continuous passage through the
furnace, samples shall also be attached in-between if the number
permits.
Ch.2 Sec.2 B
804 One tensile and nine Charpy V-notch test pieces shall be taken
from each sample, see Figure 1. The tensile test piece and three
impact test pieces shall be taken from the side of the link opposite
the flash weld. Three impact test pieces shall be taken across the
flash weld with the notch centred in the middle. The position of
the weld shall be accurately identified by etching with a suitable
reagent before cutting the notches. Three impact test pieces shall
be taken from the outer bend region, except as provided in 805.
The longitudinal axis of the test pieces shall be one third radius
below the surface.
Ch.2 Sec.2 B
805 The frequency of impact testing at the bend may be reduced
subject to agreement between the manufacturer and purchaser. In
such cases it shall be documented that the requirements are consistently
achieved. Test results from at least five heats of a particular
grade shall be provided for this purpose.
Ch.2 Sec.2 B
806 The preparation of test pieces and the procedures used for
mechanical testing shall comply with the relevant requirements of
DNV-OS-B101. The results shall comply with the mechanical properties
specified in Table C3.
Ch.2 Sec.2 B
807 If the tensile test fails, two further test pieces selected from
the same sample shall be tested. If either of the re-tests fails,
the sampling length represented is rejected.
Ch.2 Sec.2 B
808 If the impact test fails, three further test pieces selected from
the same sample shall be tested. The values shall be added to those
previously obtained to form a new average. This average shall comply
with the requirements. No more than two individual results shall
be lower than the specified minimum average and no more than one
individual result shall be below the specified minimum single value.
If the re-test fails, the sampling length represented is rejected.
Ch.2 Sec.2 B
809 Rejected lengths may be submitted to re-heat treatment after
agreement between manufacturer and purchaser. In such cases the
tests previously performed shall be repeated and the results must
meet the requirements.
Fig. 1 Position of test pieces
Ch.2 Sec.2
B 900 Dimensions and tolerances
Ch.2 Sec.2 B
901 After proof load testing, the pitch length in chain intended
to work in way of windlass and fairlead shall be measured five links
at a time with an overlap of at least one link. The measurements
shall be made over the entire length of chain while the chain is
either loaded to approximately 10% of the proof load or
otherwise suitably arranged to enable correct measurements. The
length over five links shall meet the tolerances given in Table C1. The links held in the
end blocks may be excluded from these measurements.
Ch.2 Sec.2 B
902 If a five link length is short, the chain may be stretched by
loading as detailed in 601. If a five link length exceeds the plus
tolerance, the affected links are rejected.
Ch.2 Sec.2 B
903 Measurements of all other dimensions, as detailed in 904 to
907, shall be made on at least 5% of the links distributed over
the length.
Ch.2 Sec.2 B
904 The diameter shall be measured at the crown. The average diameter
based on two perpendicular measurements must have no negative tolerance
and the plus tolerance shall not exceed 5% of nominal diameter.
As a result of being bent around the anvil, however, a particular
diameter may be smaller than the nominal:| ¾ | for nominal diameter up to 84 mm: | - 2 mm |
| ¾ | for nominal diameter 85 through 122 mm: | - 3 mm |
| ¾ | for nominal diameter 123 through 152
mm: | - 4 mm |
| ¾ | for nominal diameter 153 through 184
mm: | - 6 mm |
| ¾ | for nominal diameter 185 through 210
mm: | - 7.5 mm |
Ch.2 Sec.2 B
905 The largest diameter at the flash weld area shall be checked.
The plus tolerance shall not exceed 15% of nominal chain
diameter.
Ch.2 Sec.2 B
906 The outside length and width shall be measured. Tolerances
shall not exceed 2.5%.
Ch.2 Sec.2 B
907 The stud position and alignment shall be measured. The stud
shall be located in the link centrally, and at right angles to the
sides of the link. The following tolerances are acceptable provided
that the stud fits snugly and its ends lie flush against the inside
of the link:| — | maximum off-centre distance
shall be 10% of the nominal chain diameter |
| — | maximum angular misalignment shall be four degrees. |
Ch.2 Sec.2 B
908 If one or two links fail to meet tolerance requirements, measurements
of the particular dimension shall be made on 20 more links on each
side of the affected links. If a third link fails to meet tolerance
requirements, measurements of the particular dimension shall be
made on all links. Links that fail to meet the requirements shall
be rejected, unless otherwise agreed with the purchaser.Ch.2 Sec.2
B 1000 Inspection
Ch.2 Sec.2 B
1001 After proof load testing, all links shall be visually inspected
and non-destructive tested. Prior to inspection the surfaces shall
be cleaned by shot or sand blasting.
Ch.2 Sec.2 B
1002 All accessible surfaces, including the outer bends, shall be
visually inspected. Links shall be free from burrs, rough edges,
cracks, dents, cuts, distinct trimming marks, and other injurious
imperfections. Studs shall be securely fastened; no axial or lateral
movement is permitted.
Ch.2 Sec.2 B
1003 The flash butt welds and the areas gripped by the clamping
dies shall be magnetic particle tested (MT). Additionally, for chain
with nominal diameter 132 mm or above, 10% of the links
distributed over the length shall be tested on all accessible surfaces.
Testing shall be performed in accordance with ASTM E709 or another
recognised standard using wet continuous magnetisation technique.
Links shall be free from:| — | relevant linear indications
exceeding 1.6 mm in transverse direction |
| — | relevant linear indications exceeding 3.2 mm in longitudinal
direction |
| — | relevant non-linear indications exceeding 4.8 mm. |
Ch.2 Sec.2 B
1004 The flash butt welds shall be ultrasonic tested (UT) in accordance
with ASTM E587 or another recognised standard using single probe,
angle-beam shear waves in the range from 45 to 70°. Guidance note:
It should be recognised that the single probe technique has
limitations as far as testing of the central region is concerned
and that flash weld imperfections such as flat spots may have poor
reflectivity. However, the central region would normally not contain the
typical imperfections that can occur in flash butt welds. Where
it is deemed necessary, detectability of imperfections can be improved
by using a tandem technique. ---e-n-d---o-f---G-u-i-d-a-n-c-e---n-o-t-e---
Ch.2 Sec.2 B
1005 UT equipment shall be calibrated using IIW blocks. The search
unit shall be checked for beam exit point and angle of reflection
at least once per working shift or 8 hours, whichever comes first.
Ch.2 Sec.2 B
1006 UT reference blocks shall be made from a chain link that is
similar in diameter, surface condition, chemistry, and processing
history to the production links. The block shall contain two surface
notch reflectors in the plane of the weld oriented 180° apart; one
located on the inner surface adjacent to the stud, and one located
on the outer surface. The notch shall be maximum 3 mm wide and cut
to a depth 4% of nominal diameter or 5 mm, whichever is
smaller. The notch shall be cut circular with radius 15 mm. With
the search unit positioned, the instrument is calibrated to obtain
indication amplitude from both reflectors of approximately 75% of
full screen height. The procedure shall be repeated from the other
side of the weld.
Ch.2 Sec.2 B
1007 UT of production links shall be performed by scanning along
the circumference from both sides of the weld with the amplitude
calibration increased by 6 dB. Indications equal to or larger in
amplitude to that of the reference notch, when properly corrected
for distance, are not accepted.
Ch.2 Sec.2 B
1008 Stud welds, if used, shall be visually inspected. The toes
of the fillets shall have a smooth transition to the link with no
undercuts exceeding 1.0 mm. Additionally, at least 10% of the
stud welds distributed through the length shall be liquid penetrant
or magnetic particle tested. Cracks, lack of fusion or gross porosity
are not accepted. If defects are found, testing shall be extended
to all stud welds in that length. Ch.2 Sec.2
B 1100 Repair
Ch.2 Sec.2 B
1101 Defects may be removed by grinding to a depth of 5% of
the nominal diameter.
Ch.2 Sec.2 B
1102 Rejected links shall be cut out and replaced by connecting
common links (splice links) or detachable joining shackles.
Ch.2 Sec.2 B
1103 Splice links to connect lengths of heat treated chain or to
replace cut out links without the necessity for re-heat treatment
of the whole length shall be made in accordance with a procedure
approved by the purchaser. The manufacture and heat treatment of
splice links shall not affect the properties of the adjoining links.
The temperature reached by adjoining links shall not exceed 300°C.
Ch.2 Sec.2 B
1104 The use of splice links is restricted to three links, on average,
in each 100 m of chain. Each splice link included in a chain shall
be proof load tested, measured, inspected, and identified as detailed
in 600, 900, 1000, and 1200.
Ch.2 Sec.2 B
1105 A second identical splice link shall be made for mechanical
testing as detailed in 800. Where a number of splice links are included
and these are made in series, the link for mechanical testing may
represent five splice links from the same heat of steel.
Ch.2 Sec.2 B
1106 Detachable joining shackles to connect lengths of heat treated
chain or to replace cut out links shall be in accordance with C.
The use of these is subject to the approval of the purchaser in
terms of the number and type permitted.Ch.2 Sec.2
B 1200 Identification
Ch.2 Sec.2 B
1201 Each length of chain shall be identified with at least the following:| — | identification number or other
marking that will enable the history of the length to be traced |
| — | chain grade designation |
| — | connecting common links, if used, shall have unique identification
numbers. |
Ch.2 Sec.2 B
1202 The chain shall be marked at the following places:| — | at each end |
| — | at intervals not exceeding 100 m |
| — | on connecting common links |
| — | on links next to shackles or connecting common links. |
Ch.2 Sec.2 B
1203 The identification marks shall be placed on the studs or,
in the case of stud less links, on the outside of the link opposite
the flash weld. Marking by welding is not permitted on stud less
links.Ch.2 Sec.2
C. Chain Accessories
Ch.2 Sec.2
C 100 Scope
Ch.2 Sec.2 C
101 These requirements are supplementary to A and apply to chain
accessories.
Ch.2 Sec.2 C
102 Where the manufacture of materials and accessories, heat treatments,
machining, testing and inspections involve several parties, the
purchaser should establish by contract agreement, at the time of
ordering, the responsibility of the various parties for meeting
the requirements.Ch.2 Sec.2
C 200 Design
Ch.2 Sec.2 C
201 Accessories shall be manufactured in accordance with ISO 1704
or purchaser-approved drawings showing the finished dimensions and
the surfaces that will be subjected to significant loading. Accessories
of unconventional design shall have their drawings accompanied by
calculations or design reports.
Ch.2 Sec.2 C
202 Detailed design of Kenter shackles shall be according to API
Spec 2F. Machining of Kenter shackles shall result in fillet radius
minimum 3% of nominal diameter.Ch.2 Sec.2
C 300 Proof load testing
Ch.2 Sec.2 C
301 All accessories shall be proof load tested in the condition of
supply and shall withstand without fracture the proof load prescribed
in Table C1 for the stud link
chain grade and size for which they are intended.
Ch.2 Sec.2 C
302 In the event of a test failure, the accessory shall be rejected.
Testing of the remaining accessories shall be considered acceptable
if they meet the requirement and if it has been determined by examination
that the probable cause of failure is not present in any of the
remaining accessories.Ch.2 Sec.2
C 400 Breaking load testing
Ch.2 Sec.2 C
401 At least one accessory out of every test unit shall be breaking
load tested in the condition of supply and shall withstand without
fracture the breaking load prescribed in Table C1 for the chain
grade and size for which they are intended. It shall be considered
acceptable if the samples show no sign of fracture after application
of the specified minimum load for 30 seconds.
Ch.2 Sec.2 C
402 A test unit shall consist of up to 25 accessories of the same
type, grade and size, made from the same heat of steel, and heat
treated in the same furnace charge.
Ch.2 Sec.2 C
403 For individually produced accessories or less than five produced
accessories, alternative testing may be agreed between the manufacturer
and purchaser.
Ch.2 Sec.2 C
404 Except as provided in 405, accessories that have been breaking
load tested shall be discarded and not used as part of an outfit.
Ch.2 Sec.2 C
405 Accessories that have been breaking load tested may be used
as part of an outfit provided that: | — | the accessories are of increased
dimensions or alternatively a material with higher strength characteristics
is used, and |
| — | it is verified by procedure test that such accessories
are so designed that the breaking strength is not less than 1.4 times
the breaking load of the chain cable for which they are intended. |
Ch.2 Sec.2 C
406 In the event of a test failure, two further breaking load tests
shall be made. The test unit shall be considered acceptable if both
additional tests meet the requirement and if it has been determined
by examination that the probable cause of failure is not present
in any of the remaining accessories.Ch.2 Sec.2
C 500 Mechanical testing
Ch.2 Sec.2 C
501 At least one accessory out of every test unit shall be tensile
and impact tested in the condition of supply. Except as provided
in 503, test pieces shall be taken from proof load tested or breaking
load tested full size accessories. For each test unit, one tensile
and three Charpy-V-notch test pieces shall be taken.
Ch.2 Sec.2 C
502 A test unit shall consist of up to 25 accessories of the same
type, grade and size, made from the same heat of steel, and heat
treated in the same furnace charge.
Ch.2 Sec.2 C
503 For individually produced accessories or less than five produced
accessories, alternative to testing full size accessories may be
agreed between the manufacturer and purchaser provided that: | — | the alternative testing is described
in a written procedure, and |
| — | the separately forged coupon have a cross-section and
a reduction ratio similar to that of the accessories represented,
and |
| — | it is verified by procedure test that coupon properties
are representative of accessory properties. |
Ch.2 Sec.2
C 600 Dimensions and tolerances
Ch.2 Sec.2 C
601 After proof load testing, at least one accessory out of every
test unit shall be checked for dimensions. Where applicable, the
measurements shall include detachable component parts.
Ch.2 Sec.2 C
602 The diameter must have no negative tolerance. Unless otherwise
specified by the purchaser, the plus tolerance on diameter shall
not exceed 5% and tolerances on other dimensions shall
not exceed plus or minus 2.5%.
Ch.2 Sec.2 C
603 If an accessory fails to meet the tolerance requirements or
if Kenter shackles or similar designs are loose upon re-assembly,
it shall be rejected and all remaining accessories in the test unit
shall be measured.Ch.2 Sec.2
C 700 Inspection
Ch.2 Sec.2 C
701 After proof load testing, all accessories shall be visually inspected
and non-destructive tested. Prior to inspection the non-machined
surfaces shall be cleaned by shot or sand blasting. Where applicable,
the accessories shall be dismantled for inspection of internal surfaces.
Ch.2 Sec.2 C
702 All accessible surfaces shall be visually inspected and be free
from burrs, rough edges, cracks, dents, cuts, and other injurious
imperfections.
Ch.2 Sec.2 C
703 All machined surfaces, fillets, abrupt changes in section, and
surfaces that will be subjected to significant loading, as indicated
on drawings, shall be magnetic particle tested (MT). Testing shall
be performed in accordance with standards referenced in Sec.1 A600. Surfaces shall be free
from:| — | relevant linear indications
exceeding 1.6 mm in transverse direction |
| — | relevant linear indications exceeding 3.2 mm in longitudinal
direction |
| — | relevant non-linear indications exceeding 4.8 mm. |
Ch.2 Sec.2 C
704 Requirements for ultrasonic testing are given in Sec.1 C600 (forgings) and D600 (castings).Ch.2 Sec.2
C 800 Repair
Ch.2 Sec.2 C
801 Defects on non-machined surfaces may be removed by grinding
to a depth of 5% of the nominal diameter. Grinding is not
permitted on machined surfaces, except for slight inspection grinding
on plane surfaces in order to investigate spurious indications.Ch.2 Sec.2
C 900 Identification
Ch.2 Sec.2 C
901 Each accessory shall be identified in a low stress area with
at least the following:| — | identification number or other
marking that will enable the history of the accessory to be traced |
| — | chain grade designation. |
Ch.2 Sec.2 C
902 Each detachable component part shall be marked with an identifying
number to avoid mix-up of parts.
Ch.2 Sec.2 C
903 Accessories that have been breaking load tested and are used
as part of an outfit, as permitted in C400, shall be marked with
the grade of chain for which they are intended.Ch.2 Sec.2 C
| Table C1 Formulas
for proof and breaking test loads, weight, and five link length |
| | Grade
R3 | Grade
R3S | Grade
R4 | Grade
R4S | Grade
R5 |
| Proof load, stud link (kN) | 0.0156d2
(44-0.08d) | 0.0180d2
(44-0.08d) | 0.0216d2
(44-0.08d) | 0.0240d2
(44-0.08d) | 0.0251d2
(44-0.08d) |
| Proof load, stud less (kN) | 0.0156d2
(44-0.08d) | 0.0174d2
(44-0.08d) | 0.0192d2
(44-0.08d) | 0.0213d2
(44-0.08d) | 0.0223d2
(44-0.08d) |
| Breaking load (kN) | 0.0223d2
(44-0.08d) | 0.0249d2
(44-0.08d) | 0.0274d2
(44-0.08d) | 0.0304d2
(44-0.08d) | 0.0320d2
(44-0.08d) |
| Weight, stud link (kg/m) | 0.0219d2 |
| Five link length (mm) | Minimum 22d and
maximum 22.55d |
| d is the chain nominal diameter |
Ch.2 Sec.2 C
| Table C2 Frequency
of breaking load and mechanical tests |
| Nominal
chain diameter (mm) | Maximum
sampling interval (m) |
| 74 - 85 | 152 |
| 86 - 98 | 175 |
| 99 - 111 | 198 |
| 112 - 124 | 222 |
| 125 - 137 | 250 |
| 138 - 149 | 274 |
| 150 -162 | 297 |
| 163 - 175 | 322 |
| 176 - 186 | 346 |
| 187 - 199 | 370 |
| 200 - 210 | 395 |
Ch.2 Sec.2 C
| Table C3 Minimum
mechanical properties for chain cables |
| Grade | Yield stress | Tensile strength | Elongation | Reduction of area | Charpy V-notch |
| | | | | | Base | Weld |
| Re | Rm | A5 | Z | Temperature 1) | Average energy | Single energy | Average energy | Single energy |
| N/mm2 | N/mm2 | % | % | °C | J | J | J | J |
| R3 | 410 | 690 | 17 | 50 2) | 0 | 60 | 45 | 50 | 38 |
| -20 | 40 | 30 | 30 | 23 |
| R3S | 490 | 770 | 15 | 50 2) | 0 | 65 | 49 | 53 | 40 |
| -20 | 45 | 34 | 33 | 25 |
| R4 | 580 | 860 | 12 | 50 3) | -20 | 50 | 38 | 36 | 27 |
| R4S | 700 | 960 | 12 | 50 3) | -20 | 56 | 42 | 40 | 30 |
| R5 | 760 | 1000 | 12 | 50 3) | -20 | 58 | 44 | 42 | 32 |
1) For grade R3 and R3S, testing
may be carried out at either 0°C or -20°C.
2) For cast accessories, the
minimum value shall be 40%.
3) For cast accessories, the
minimum value shall be 35%. |
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