3.1.1 The
materials used for major structural and machinery components are to
be manufactured and tested in accordance with the requirements of
the Rules for the Manufacture, Testing and Certification of
Materials (hereinafter referred to as the Rules for Materials).
These components include hull support structure, pod body, pod strut,
shafting and propellers.
3.1.2 Components
of novel design or components manufactured from materials not covered
by the Rules for Materials are to be subject to evaluation and approval
by LR prior to manufacture.
3.1.3 Material
specifications, see
Vol 2, Pt 4, Ch 4, 2.2 Documentation required for design review 2.2.1.(g), for propulsion shaft and slewing ring bearings, gearing and
couplings are to be approved by LR prior to manufacture. The specification
is to include details of the grade of material, including the target
range of chemical composition that is to be reported on the certificate,
the required mechanical properties, heat treatment details including
temperatures and hold times, details of necessary non-destructive
examinations including acceptance levels. Additionally, any steel
cleanness or microstructure requirements are to be included. These
components are to be manufactured under survey.
3.1.4 For
propulsion shaft rolling element bearings the amount of retained austenite
is to be determined and is not to exceed 4 per cent for nominally
bainitic structures.
3.1.5 Where
load carrying threaded fasteners screw directly into structural castings,
the integrity of the casting is to be such that there is no porosity
or shrinkage in the area of the connection.