3.2.1 Turbine
rotors, cylinders and associated components fabricated by means of
welding will be considered for acceptance if constructed by firms
whose works are properly equipped to undertake welding to equivalent
standards, for rotors and cylinders respectively, to those required
by the Rules for Class 1 and Class 2/1 welded pressure vessels, see
Pt 5, Ch 17, 1 General to Pt 5, Ch 17, 6 Non-Destructive Examination.
3.2.3 Before
work is commenced, manufacturers are to submit for consideration details
of proposed welding procedures and their proposals for routine examination
of joints by non-destructive means.
3.2.4 Materials
used in the construction of turbine rotors, cylinders, diaphragms,
condensers, etc. are to be of welding quality.
3.2.5 Where
it is proposed to construct rotors from two or more forged components
joined by welding, full details of the chemical composition, mechanical
properties and heat treatment of the materials, together with particulars
of the welding consumables, an outline of the welding procedure, method
of fabrication and heat treatment, are to be submitted for consideration.
3.2.6 Joints
in rotors and major joints in cylinders are to be designed as full-strength
welds and for complete fusion of the joint.
3.2.7 Adequate
preheating is to be employed for mild steel cylinders and components
and where the metal thickness exceeds 44 mm, and for all low alloy
steel cylinders and components and for any part where necessitated
by joint restraint.