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DNV-OS-B101 Metallic Materials
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Ch.2 Sec.6
C. Miscellaneous
Ch.2 Sec.6
C 100 Chemical composition
Ch.2 Sec.6 C
101 The chemical composition of samples taken from each ladle
of each cast shall be determined by the manufacturer in an adequately
equipped and competently staffed laboratory and shall comply with
the appropriate requirements of this standard.
Ch.2 Sec.6 C
102 The manufacturer's declared analysis will be accepted subject
to occasional checks if required by the purchaser.Ch.2 Sec.6
C 200 Heat treatment
Ch.2 Sec.6 C
201 All materials shall be supplied in a condition complying with
the appropriate requirements of this standard.
Ch.2 Sec.6 C
202 Heat treatment shall be carried out in properly constructed
furnaces which are efficiently maintained and have adequate means
for control and recording of temperature. The furnace dimensions
shall be such as to allow the material to be uniformly heated to
the specified temperature.Temperature uniformity of heat treatment furnace shall be
verified by the manufacturer.
Ch.2 Sec.6 C
203 In the case of very large castings or forgings alternative methods
for heat treatment will be specially considered.
Ch.2 Sec.6
C 300 Selection of test material
Ch.2 Sec.6 C
301 Test material sufficient for the required tests and preferably
also for possible retest purposes shall be provided. The test material
shall be representative of the test unit or sample product and shall
not be separated until all the specified heat treatment has been
completed, unless otherwise agreed. Ch.2 Sec.6
C 400 Testing
Ch.2 Sec.6 C
401 The appropriate tests specified in this section shall be carried
out at the place of manufacture before materials are dispatched.
If the necessary facilities are not available at the manufacturer's
works, the testing shall be carried out at a recognised testing
laboratory.
Ch.2 Sec.6 C
402 In the event of any material proving unsatisfactory during
subsequent processing or fabrication, such material shall be rejected,
notwithstanding any previous certification. The purchaser may require
further tests of materials from affected test units.Ch.2 Sec.6
C 500 Retesting
Ch.2 Sec.6 C
501 When the result of any test, other than impact test and Z-testing,
fail to meet the requirements, two further tests may be made from
the same sample. If both of these additional tests are satisfactory,
the test unit may be accepted.
Ch.2 Sec.6 C
502 When the results from a set of three impact test pieces fail
to meet the requirements, three additional test pieces from the
same sample may be tested and the results added to those previously
obtained to form a new average. If this new average complies with
the requirements and if not more than two individual results are
lower than the required average and, of these, not more than one
result is below 70% of the specified average value, the
test unit may be accepted.
Ch.2 Sec.6 C
503 If unsatisfactory results are obtained from retests representative
of a test unit, the sample product from which the tests were made
shall be rejected. The remaining material in the test unit may be
accepted provided that two further sample products are tested with
satisfactory result.
Ch.2 Sec.6 C
504 When a test unit is rejected, the remaining sample products
in the test unit may be resubmitted individually for test, and those
which give satisfactory results may be accepted.
Ch.2 Sec.6 C
505 At the option of the manufacturer, rejected material may be
resubmitted after heat treatment or re-heat treatment, or may be
resubmitted as another grade and may then be accepted provided the
required tests are satisfactory.
Ch.2 Sec.6 C
506 If any test piece fails because of faulty preparation, visible
defects or (in the case of tensile test) because of fracturing outside
the range permitted for the appropriate gauge length, the defective
test piece may be disregarded and replaced by an additional test
piece of the same type.Ch.2 Sec.6
C 600 Non-destructive testing
Ch.2 Sec.6 C
601 All finished material shall have a workmanlike finish and
shall be free from internal and surface defects prejudicial to the
use of the material for the intended application. Otherwise the
material shall comply with the appropriate specific requirements
of this standard.Ch.2 Sec.6
C 700 Correction of defects
Ch.2 Sec.6 C
701 When unacceptable defects are found, these shall be removed
by appropriate methods and rectified in accordance with the applicable
requirements of this standard. Shallow grooves or depression resulting
from the removal of defects may, by agreement, be accepted provided
that they will cause no appreciable reduction in the strength of
the material and that they are suitably smoothed and contoured.
Ch.2 Sec.6 C
702 Repair of defects by welding shall only be carried out when
permitted by the appropriate specific requirements. Proposals to
repair a defective material by welding shall be submitted to the
purchaser for acceptance before this work is commenced. Such proposals
shall include appropriate details of the extent and position of
defects. The manufacturer may be required to carry out welding procedure
qualification tests to demonstrate that satisfactory mechanical
properties can be obtained.
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