Section
1 General requirements
1.1 Scope
1.1.1 This Section
gives the general requirements for steel castings intended for use
in the construction of ships, other marine structures, machinery,
boilers, pressure vessels and piping systems.
1.1.3 As an alternative to Ch 4, 1.1 Scope 1.1.2, C and C-Mn steel castings and alloy steel castings
which comply with National or proprietary specifications may be accepted provided that
these specifications give reasonable equivalence to the requirements of this Chapter or
alternatively are approved for a specific application. Generally, survey and
certification are to be carried out in accordance with the requirements of Ch 1 General Requirements.
1.1.4 Where small
castings are produced in large quantities, or where castings of the
same type are produced in regular quantities, alternative survey procedures,
in accordance with Ch 1, 2.4 Materials Quality Scheme, may
be adopted.
1.2 Manufacture
1.2.1 Castings
are to be made at foundries approved by LR. The steel used is to be
manufactured by a process approved by Clasifications Register (hereinafter
referred as 'LR').
1.2.2 All flame
cutting, scarfing or arc-air gouging to remove surplus metal is to
be undertaken in accordance with recognised good practice and is to
be carried out before the final heat treatment. Preheating is to be
employed where necessitated by the chemical composition and/or thickness
of the casting. The affected areas are to be either machined or ground
smooth for a depth of about 2 mm unless it has been shown that the
material has not been damaged by the cutting process. Special examination
will be required to find any cracking in way of the cut surfaces.
1.2.3 Where two or more castings are joined by welding to form a composite item,
details of the proposed welding procedure are to be submitted for approval. The welding
procedure and welders are to be qualified in accordance with Ch 12 Welding Qualifications.
1.2.4 Temporary welds made for operations such as lifting, handling, staging, etc. are to be
in accordance with approved welding procedures and qualified welders, and are to be
removed, ground, and inspected using suitable surface NDE methods. All temporary welds
shall be recorded for traceability purposes.
1.3 Quality of castings
1.3.1 All castings
are to be free from surface or internal defects which would be prejudicial
to their proper application in service. The surface finish is to be
in accordance with good practice and any specific requirements of
the approved specification.
1.3.2 The surfaces
are not to be hammered, peened or treated in any way which may obscure
defects.
1.3.3 The locations
of all chaplets are to be noted and to be subject to close visual
inspection (and when necessary ultrasonic examination) to ensure complete
fusion.
1.3.4 In the event of any casting proving to be defective during subsequent machining or
testing it is to be rejected notwithstanding any previous certification.
1.4 Chemical composition
1.4.1 All castings
are to be made from killed steel. The chemical composition of the
ladle sample is to be within the limits given in the relevant Section
of this Chapter. Where general overall limits are specified, the chemical
composition is to be appropriate for the type of steel, dimensions
and required mechanical properties of the castings.
1.5 Heat treatment
1.5.1 All castings are to be heat treated in accordance with the requirements
given in the relevant Section of this Chapter.
1.5.2 Heat treatment is to be carried out in a properly constructed furnace which
is efficiently maintained and has adequate means of temperature control. The furnace
dimensions are to be such as to allow the steel castings to be uniformly heated to the
necessary temperature. Sufficient thermocouples are to be connected to the steel
castings to show that their temperature is adequately uniform and the temperatures are
to be recorded throughout the heat treatment. The records are to identify the furnace
that was used and give details of the individual steel castings, the heat treatment
temperature and time at temperature and the date. The Surveyor is to examine the charts
and confirm the details on the certificate. In the case of very large components which
require heat treatment, alternative methods will be specially considered.
1.5.3 As an alternative procedure to the connection of thermocouples as required
by Ch 4, 1.5 Heat treatment 1.5.2, temperature uniformity surveys of
the heat treatment furnace may be accepted subject to approval by LR, Materials and NDE
department. An initial temperature uniformity survey in the furnace fully loaded
condition is required to be carried out in accordance with recognised standards (e.g.
ASTM A991/A991M). Regular temperature uniformity surveys are then subsequently required
at a frequency of at least once per year.
1.5.4 If a casting is locally reheated, or any straightening operation is
performed after the final heat treatment, a subsequent stress relieving heat treatment
may be required in order to avoid the possibility of harmful residual stresses. The
manufacturer shall have strict control of this temperature in order to avoid any
detrimental effects on the final heat treatment and resultant microstructure and
mechanical properties of the casting.
1.6 Test material and test specimens
1.6.1 Test material sufficient for the tests specified in Sections Ch 4, 2 Castings for ship and other structural applications to Ch 4, 9 Steel castings for container corner fittings and for possible re-test purposes is to be
provided for each casting. The size of the test samples for mechanical testing is to be
such that the heat treatment and microstructure is representative of the ruling section
of the casting, i.e., the section for which the specified mechanical properties apply
(as referenced in ISO 683-1 and ISO 683-2). For C and C-Mn steel castings this is in
general to be achieved as follows: The test samples are to be either integrally cast or
gated to the castings and shall have a thickness (ts) of not less than
the ruling section of the casting, or 30 mm, whichever is larger.
1.6.2 For large thickness castings other than stern tube, stern frame, anchor and
rudder horn,(ts) does not normally need to exceed 150 mm. The length
and width of the test sample is normally to be at least three times ts, as
shown in Figure 4.1.1 Specimen position relative to
test sample dimension taken as ts x 3ts x
3ts for section thickness greater than 56 mm, unless otherwise agreed with LR.
Longer or wider test samples may be necessary in order to accommodate the required test
specimens. For castings for stern tubes, stern frames, anchors and rudder horns, the
test sample thickness ts shall represent the ruling section.
Note Shorter widths or lengths may be accepted for test samples
where the actual casting width or length (tA) is in the range
between (ts) and (3ts).
Note 1. For a general casting with dimensions 140 x 160 x 1250 mm
the required test sample size would typically be 140 x 160 x 420 mm (that is:
ts x tA x 3ts).
1.6.3 For alloy steel castings the manufacturer shall propose dimensions for the test sample
and demonstrate that they are representative.
Figure 4.1.1 Specimen position relative to
test sample dimension taken as ts x 3ts x
3ts for section thickness greater than 56 mm
Figure 4.1.2 Note 2: test sample gated to
stern tube casting
1.6.4 For test samples with thicknesses up to and including 56 mm, the
longitudinal axis of the test specimens is to be located not lower than 14 mm from the
surface in the thickness direction. For test samples with thicknesses greater than 56
mm, the longitudinal axis of the test specimens is to be located not lower than ¼
ts from the surface in accordance with the requirements of ISO
4990. Test specimens shall be taken in such a way that no part of the gauge length is
machined from material closer than ts to any of the other surfaces.
For impact testing, this requirement shall apply to the complete test specimen,
see
Figure 4.1.1 Specimen position relative to
test sample dimension taken as ts x 3ts x
3ts for section thickness greater than 56 mm for location of test specimens in
relation to the test sample.
1.6.5 The test
samples are not to be detached from the casting until the heat treatment
specified in Ch 4, 1.5 Heat treatment 1.5.1 has been completed
and they have been properly identified.
1.6.6 As an alternative
to Ch 4, 1.6 Test material and test specimens 1.6.1 and Ch 4, 1.6 Test material and test specimens 1.6.5, where a number of small castings
of about the same size, each of which is under 1000 kg in mass, are
made from one cast and heat treated in the same furnace charge, a
batch testing procedure may be adopted, using separately cast test
samples of suitable dimensions. The test samples are to be properly
identified and heat treated together with the castings which they
represent. At least one test sample is to be provided for each batch
of castings.
1.6.7 The test specimens are to be prepared in accordance with the requirements of
Ch 2 Testing Procedures for Metallic Materials. One tensile test specimen and one set of impact tests are
to be taken from each test sample. Tensile test specimens are to have a cross-sectional
area of not less than 150 mm2.
1.7 Visual and surface Non-Destructive
Examination
1.7.1 This Section gives the general requirements for non-destructive examination
of steel castings. As an alternative, castings may be examined in accordance with a
National Specification, provided it gives reasonable equivalence to these Rules.
1.7.2 All castings are to be cleaned and adequately prepared for inspection.
Suitable methods include pickling, caustic cleaning, wire brushing, local grinding, and
shot or sand blasting. Castings are to be examined in the final delivery condition.
Where a casting is supplied in semi-finished condition, the manufacturer is to take into
account the quality level, including the functional and performance requirements, of
final finished machined components.
1.7.3 The surfaces are not to be hammered, peened or treated in any way which may
obscure defects.
1.7.4 Unless otherwise agreed, the accuracy and verification of dimensions are the
responsibility of the manufacturer, and a report on the relevant examinations is to be
submitted to the Surveyor, who may require checks to be made and to witness such checks.
Where intermediate inspections have been performed, the manufacturer is to provide
reports of the results upon the request of the Surveyor.
1.7.5 All castings are to be subjected to 100 per cent visual examination of all
accessible surfaces by the manufacturer and are then to be presented to the Surveyor for
visual examination. Where applicable, this is to include the examination of internal
surfaces. Castings are to be subject to magnetic particle examination or liquid
penetrant testing (for austenitic stainless steel castings, see
Ch 4, 8 Stainless steel castings) in accordance with Ch 4, 1.7 Visual and surface Non-Destructive Examination 1.7.9, unless more specific requirements for
Non-Destructive Examination are included in subsequent Sections of this Chapter, other
parts of the Rules or the agreed specification. Viewing conditions at the inspected
surfaces are to be in accordance with a nationally or internationally recognised
standard.
1.7.6 Where specified or required by the Rules, Non-Destructive Examination is to
be carried out before acceptance. All tests are to be in accordance with the
requirements of Ch 1, 5 Non-destructive examination. Non-Destructive Testing applied for acceptance
purposes to support final casting certification is to be made after the final heat
treatment of the casting.
1.7.7 The manufacturer is to provide the Surveyor with a signed report confirming
that non-destructive examination has been carried out and that such inspection has not
revealed any significant defects.
1.7.8 Where magnetic particle examination is specified or required, this is to be
carried out using a suspension of magnetic particles in a suitable fluid. The dry powder
method is not acceptable for the final inspection. Prods are not permitted on finished
machined surfaces.
1.7.9 Where required, magnetic particle or liquid penetrant testing is to be
carried out by the manufacturer whenever appropriate and also when the castings are in
the finished condition. For surface inspection NDE methods, the surface quality is to be
a minimum value of Ra less than or equal to 6,3 μm. The tests are to
be made in the presence of the Surveyor unless otherwise specially agreed. The castings
are to be examined in the following areas in addition to any areas defined in subsequent
Sections of this Chapter:
-
At all accessible fillets and changes of section.
-
At positions where surplus metal has been removed by flame cutting,
scarfing or arc-air gouging.
-
In way of fabrication weld preparations, for a distance not less than
50 mm from the edge.
-
In way of welds.
-
In way of chaplets.
-
At other positions agreed with the Surveyor to include areas which
may be subjected to high stress in service.
1.7.10 The testing procedures, apparatus and conditions of magnetic particle testing and liquid
penetrant testing are to comply with recognised National or International Standards.
Magnetic particle testing is preferable to penetrant testing except in the following
cases:
- Austenitic stainless steels.
- Interpretation of open visual or magnetic particle indications.
- At the instruction of the Surveyor, where a particular need for penetrant testing
has been identified.
1.7.11 For magnetic particle testing, attention is to be paid to the contact between the
casting and the clamping devices of stationary magnetisation benches in order to avoid
local overheating or burning damage at the casting’s surface. Prods are not permitted on
finished machined items. Note that the use of solid copper at the prod tips must be
avoided due to the risk of copper contamination of the casting. The poles of the magnets
are to have close contact with the component.
1.7.12 The AC magnetisation method is normally used, as it is more sensitive for
detecting surface indications. Where the DC magnetisation method is used, this is to be
in agreement with LR, and the reason for use clearly justified.
1.8 Volumetric Non-Destructive Examination
1.8.1 Where required by subsequent Sections or by the agreed specification,
ultrasonic examination is to be carried out by the manufacturer, but Surveyors may
request to be present in order to verify that the examination is carried out in
accordance with the agreed procedure. Ultrasonic testing is to be carried out after
the castings have been ground, machined or shot blasted to a suitable condition,
with a minimum value surface quality of Ra less than or equal to
12,5 μm. The surfaces of castings to be examined are to be such that adequate
coupling can be established between the probe and the casting and that excessive
wear of the probe is avoided. This examination is to be carried out in the following
areas:
- At positions which may be subjected to high stresses in service, as agreed with
the Surveyor.
- In way of fabrication weld preparations, for a distance not less than 50 mm from
the edge.
- At positions where subsequent machining may expose filamentary shrinkage or
other defects (e.g. bolt holes, bearing bores).
- In way of welding.
- In way of riser positions.
- At positions where experience shows that significant internal defects may occur
– these are to be agreed between the manufacturer and the Surveyor.
1.8.2 In the case of castings such as rudder horns, which may have a large surface area
still untested after the above inspections have been applied, an additional
ultrasonic inspection of the untested areas is to be made along continuous
perpendicular grid lines on nominal 225 mm centres, scanning may be from one surface
only.
1.8.3 Volumetric inspection is normally to be carried out by ultrasonic
testing using the contact method with normal (0°) beam and/or angle beam technique.
The testing procedures, apparatus and conditions of ultrasonic testing are to comply
with the recognised National or International Standards.
1.8.5 In some cases, due to the shape, nature, or complexity of casting, or defect type or
orientation, there may be a need for radiographic testing. In such cases,
radiographic testing may be carried out on the basis of prior agreement with LR.
Where radiographic testing is to be used, National or International Standards for
both the testing method and the quality or severity level to be applied, is to be
agreed with LR. These following examples are suitable National or International
Standards as appropriate to the radiographic testing of castings, and casting
thickness.
- ASTM E446;
- ASTM E186;
- ASTM E280;
- ISO 4993.
1.8.6 Radiographic examination, where required, is to be carried out by the
manufacturer in areas generally as indicated for ultrasonic examination in Ch 4, 1.8 Volumetric Non-Destructive Examination 1.8.1. All radiographs are to be submitted to the Surveyor for review
and acceptance. The radiographic technique and acceptance standards are to be to the
satisfaction of the Surveyor and in accordance with any requirements of the approved
procedure.
1.8.7 A suitable quality level for marine castings would normally be severity Level 2 or 3
(of the above standards), or as specified by the design authority, depending on the
location zone and type of casting. Other severity levels may be applied and are to
be agreed with LR.
1.8.9 Ultrasonic scans should be made using a 0° probe of 1–4 MHz (usually 2
MHz) frequency, and angle probes, where required. Whenever possible, scanning is to
be performed from both surfaces of the casting and from surfaces perpendicular to
each other.
1.8.10 The back wall echo obtained on parallel sections is to be used to monitor variations
in probe coupling and material attenuation. Any reduction in the amplitude of the
back wall echo due to material properties is to be corrected. Attenuation in excess
of 30 dB/m could be indicative of an unsatisfactory annealing heat treatment and may
adversely affect the testing and void the results. In such cases of excessive
attenuation, this is to be investigated, and suitable mitigation measures carried
out for effective ultrasonic testing to continue, where possible.
1.8.11 Machined surfaces, especially those in the vicinity of riser locations and in the
bores of stern boss castings, are to also be subject to a near surface
(approximately 25 mm) scan using a twin crystal 0° probe.
1.8.12 Additional scans on machined surfaces are of particular importance in cases where
bolt holes are to be drilled or where surplus material such as ‘padding’ has been
removed by machining, thus moving the scanning surface closer to possible areas of
shrinkage.
1.8.13 Additionally, where possible, examination of the machined bores of castings using
circumferential scans with 70° probes are to be carried out in order that axial
radial planar flaws such as hot tears can be detected. Fillet radii are to be
examined using 45°, 60° or 70° probes scanning from the surfaces/direction likely to
give the best reflection, primarily to determine the presence of any cracks within
the radiused areas, and as an additional scan to confirm any indications that may
have been detected with 0° probe(s) within this area.
1.8.14 In the examinations of those zones nominated for ultrasonic examination,
the reference sensitivity for the 0° probe is to be established against a 6 mm
reflector. Sensitivity can be calibrated either against 6 mm diameter flat bottomed
hole(s) in a reference block (or series of blocks) corresponding to the thickness of
the casting provided that a transfer correction is made, using the DAC
(Distance-AmplitudeCorrection) method, or by using the DGS (Distance-Gain-Size)
method.
1.8.15 Where angle probes are used the reference sensitivity is to be established against an
appropriate 6 mm reflector (e.g. reference reflectors angled perpendicular to the
sound beam) for the DAC method, or equivalent using the DGS method.
1.8.16 The DGS diagrams issued by a probe manufacturer are to be used as they
identify the difference in dB between the amplitude of a back wall echo and that
expected from a 6 mm diameter disc reflector. By adding this difference to the
sensitivity level initially set by adjusting a back wall echo to a reference height,
e.g. 80 per cent, the amended reference level will be representative of a 6 mm
diameter disc reflector. Similar calculations can be used for evaluation purposes to
establish the difference in dB between a back wall reflector and disc reflectors of
other diameters, such as 12 or 15 mm.
1.8.17 Following Transfer Correction, differences in attenuation or surface
condition between the reference block and the casting, any indications received from
the nominated zones in the casting that exceed the 6 mm reference level are to be
marked for evaluation against the acceptance criteria given in Table 4.2.6 Ultrasonic Acceptance Criteria for
steel castings – Using DGS or DAC system. Evaluation is to
include additional scans with angle probes in order that the full extent of the
discontinuity can be plotted.
1.9 Reporting and personnel certification
1.9.1 All NDE, including personnel, procedural, test method and reporting
criteria, is to be in accordance with the requirements of Ch 1, 5 Non-destructive examination, and applicable Sections for NDE methods.
In addition, reports of surface inspections are to include at least the following
items:
- For penetrant testing, the penetrant system used.
- For magnetic testing, the method of magnetising, test media, and magnetic field
strength and magnetic flux indicators (where appropriate).
1.9.2 The reporting criteria for ultrasonic inspection are to be in accordance
with the requirements of Ch 1, 5.6 Non-destructive examination reports and Ch 1, 5.10 Ultrasonic testing. In addition, reports
of ultrasonic inspections should include at least the following items:
- Flaw detector.
- Probe type, size, angle and frequency.
- Calibration and reference blocks used.
- Sensitivity method including reflector size and transfer
correction.
- Maximum scanning rate.
- Couplant.
1.9.3 Personnel engaged in visual examination are to have sufficient knowledge and
experience; however, they may be exempted from formal qualifications.
1.9.4 The NDE personnel’s certificates and competence are to comprise all
industrial sectors and techniques being applied by the manufacturer or its
sub-contractors. Certificates are to be made available to LR for verification, when
requested.
1.9.5 The operator carrying out the NDE and interpreting indications should, as
a minimum, be qualified and certified to Level II in the NDE method(s) concerned.
However, operators only undertaking the gathering of data using any NDE method and
not performing data interpretation or data analysis may be qualified and certified
as appropriate, at Level I. The operator is to have adequate knowledge of materials,
weld, structures or components, NDE equipment and limitations to apply the relevant
NDE method for each application appropriately.
1.10 Pressure testing
1.10.1 Where required
by the relevant Rules, castings are to be pressure tested in the final
machined condition before final acceptance. These tests are to be
carried out in the presence of the Surveyors and are to be to their
satisfaction.
1.11 Rectification and dressing of castings
Where castings are to be repaired, the manufacturer shall exercise robust controls of
all repair operations regarding the repair of castings, with respect to dimensions, heat
treatment, inspection and quality control. Missing. Subsequent paragraph numbers
wrong.
1.11.2 When unacceptable defects are found in a casting, these are to be removed by the
following methods (or a combination of these methods):
- grinding,
- chipping,
- arc air-gouging,
- flame scarfing, or
- machining.
Where thermal methods of metal removal methods are used, e.g.
flame-scarfing or arc-air gouging, preheating shall be used and the surfaces of the
resulting excavation shall subsequently be ground smooth. Complete elimination of the
defective material is to be proven by adequate non-destructive examination.All grooves
shall have a bottom radius of approximately three times the groove depth and should be
smoothly blended with the surface area with a finish equal to that of the adjacent
surface. Shallow grooves or excavations resulting from the removal of defects may, at
the discretion of the Surveyor, be accepted provided that they will cause no appreciable
reduction in the strength of the castingsor affect the intended use, and the depth of
defect removal is not over 15 mm or 10 per cent of wall thickness, whichever is less and
that they are suitably blended by grinding. Complete elimination of the defective
material is to be verified by magnetic particle or dye penetrant testing. Small surface
irregularities sealed by welding are to be treated as weld repairs, see
Ch 4, 1.11 Rectification and dressing of castings 1.11.5.
1.11.4 Grinding
wheels for use on austenitic stainless steels are to be of an iron-free
type and shall have been used only on stainless steels.
1.11.5 All proposals to repair a defective casting by welding are to be submitted
to the Surveyor before this work is commenced. The Surveyor is to be satisfied that the
number, position and size of the defects are such that the casting can be effectively
repaired. The following apply for weld repairs:
- For C and C-Mn steel castings, weld repairs shall be suitably classified as major
or minor.
- Major repairs are those where:
- the depth is greater than 25 per cent of the wall thickness or 25 mm
whichever is less, or
- the total weld area on a casting exceeds 0,125 m2 of the
casting surface noting that, where a distance between two welds is
less than their average width, they are to be considered as one
weld.
- before welding is started, full details of the extent and location of
the repair, the proposed welding procedure, heat treatment and
subsequent inspection procedures are to be submitted for
approval.
- Minor weld repairs: Weld repairs not classified as major are considered as
minor. LR may request minor repairs in critical areas to be treated as major
repairs.
- For alloy steel castings, all repairs require approval from LR.
- After major and minor repairs are completed, the appropriate heat
treatment is to be carried out, See also
Ch 4, 1.11 Rectification and dressing of castings 1.11.13.
1.11.6 A statement and/or sketch detailing the extent and position of all welds is
to be prepared by the manufacturer. Copies of these sketches are to be submitted to
LR.
1.11.7 Welding procedures are to be qualified and shall match the final heat
treatment of the casting. All welding is to be carried out by an approved welder and in
accordance with an approved welding procedure which includes the features referred to in
Ch 4, 1.11 Rectification and dressing of castings 1.11.7 to Ch 4, 1.11 Rectification and dressing of castings 1.11.14. The welding procedures and welders are to
be qualified in accordance with Ch 12 Welding Qualifications and witnessed by the Surveyor.
Note For welding steels with a carbon content (taken as a
percentage of chemical composition) not lower than 0,23 or Ceq not lower than 0,45,
the WPQT (welding procedure qualification test) on which the WPS is based, should be
qualified on a base material having a Ceq as follows: the Ceq of the base material
should not fall below more than 0,02 of the material to be welded. (Example: WPQT for
a material with actual Ceq = 0,50 may be qualified on a material with Ceq not lower
than 0,48.)
1.11.8 Where welding
is required, a grain refining heat treatment is to be given to the
whole casting prior to carrying out welding unless agreed otherwise
with the Surveyor. Grain refining heat treatment requires heating
above the upper critical temperature.
1.11.9 Any excavations
are to be of suitable shape to allow good access for welding and,
after final preparation for welding, are to be re-examined by suitable
non-destructive testing methods to ensure that all defective material
has been eliminated.
1.11.10 All castings
in alloy steels other than austenitic and duplex stainless steels
are to be suitably preheated prior to welding. Castings in carbon-manganese
steels may also be required to be preheated, depending on their chemical
composition, the dimensions, configuration and positions of the welds.
1.11.11 Welding
is to be carried out under cover, in positions free from draughts
and adverse weather conditions. As far as possible, all welding is
to be carried out in the downhand (flat) position.
1.11.12 The welding
consumables used are to be of an appropriate composition, giving a
weld deposit with mechanical properties similar and in no way inferior
to those of the parent castings. The use of low hydrogen type welding
consumables is preferred. Welding procedure tests are to be carried
out by the manufacturer to demonstrate that satisfactory mechanical
properties can be obtained after heat treatment as detailed in Ch 4, 1.11 Rectification and dressing of castings 1.11.13, and the results of these tests
are to be presented to the Surveyor.
1.11.13 After weld repair is completed, the casting is to be given the heat
treatment specified in Ch 4, 2 Castings for ship and other structural applications to Ch 4, 9 Steel castings for container corner fittings, or a stress relieving heat treatment at a temperature of not
less than 550°C for C and C-Mn steel castings. For alloy steel castings, the heat
treatment is to be agreed with LR.. The type of heat treatment required will be
dependent on the chemical composition of the casting and the dimensions, positions and
nature of the repairs, and should not be detrimental to the properties of the casting.
1.11.14 Special
consideration may be given to a local stress relieving heat treatment
where both the welded area is small and machining of the casting has
reached an advanced stage, but prior agreement is to be obtained from
LR in writing. The welding procedure is to be such that residual stresses
are minimised.
1.11.15 On completion of heat treatment, all welds and adjacent material are to be
ground smooth and examined by magnetic particle or penetrant testing. Supplementary
examination by ultrasonic or radiographic testing may also be required depending on the
dimensions and nature of the original defect. The Surveyor is to attend at these
inspections, to witness the results of magnetic particle or penetrant examination and to
examine any radiographs. Satisfactory results are to be obtained from all forms of
Non-Destructive Examination used. The acceptance criteria for the NDE of welds are to be
in accordance with subsequent Sections of this Chapter or where these do not exist,
Table 13.2.5 Acceptance criteria for visual testing, magnetic particle and liquid penetrant
testing to Table 13.2.7 Acceptance criteria for
ultrasonic and phased array testing, as appropriate.
1.11.16 Where no
welding has been made on a casting, the manufacturer is to provide
the Surveyor with a written statement that this is the case.
1.11.17 The foundry
is to maintain full records detailing the weld procedure, heat treatment
and the extent and location of all welds made to each casting. These
records are to be available for review by the Surveyor, and copies
of individual records are to be supplied to the Surveyor on request.
1.12 Identification of castings
1.12.1 The manufacturer is to adopt a system of identification, as per the
requirements of Ch 1, 4.8 Identification of materials, which will enable
all finished castings to be traced to the original cast, and the Surveyor is to be given
full facilities to trace the castings when required.
1.12.2 Before acceptance, all castings which have been tested and inspected with
satisfactory results are to be clearly marked by the manufacturer with the following
particulars:
-
Identification number, cast number or other marking which will enable
the full history of the casting to be traced.
-
Manufacturer’s name or trade mark.
-
LR or Clasifications Register and the abbreviated name of LR's local
office.
-
Personal stamp of Surveyor responsible for inspection.
-
Test pressure, where applicable.
-
Date of final inspection.
1.12.3 Where small castings are manufactured in large numbers, modified arrangements for
identification may be specially agreed with the Surveyor, noting the general
requirements of Ch 1, 4.8 Identification of materials.
1.12.4 Where a number of light similar or identical products, such as sections and bars,
weighting ≤ 50 kg per meter, are securely fastened together in bundles, the manufacturer
may brand only each bundle. A firmly fastened durable label containing the
identification may be attached to each bundle.
1.13 Certification of materials
1.13.2 The manufacturer
is to provide the Surveyor with a written statement giving the following
particulars for each casting or batch of castings which has been accepted:
-
Purchaser's name and
order number.
-
Description of castings
and steel grade.
-
Identification number.
-
Steel-making process,
cast number, chemical analysis of ladle samples and, in the case of
the Special grade (see
Ch 4, 2 Castings for ship and other structural applications), the chemical analysis of the product or test bar.
-
General details of
heat treatment including the temperature and time at temperature.
-
Results of mechanical
tests.
-
Test pressure, where
applicable.
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