The rotor discs are commonly manufactured of grey cast
iron[1]. The SAE maintains a specification for the
manufacture of grey iron for various applications[2]. It is
primarily composed of Iron 95%, Carbon 2 to 5%,
Silicon 1 to 3%, & also contains small percentage of
Sulphur, Manganese & Phosphorus. Grey cast iron has
high specific heat capacity & thermal conductivity which
makes them suitable for making of rotor disc. Other
properties are young’s Modulus of Elasticity, Torsional
Modulus of Elasticity, Crushing Strength, Brinell
hardness & Endurance Limit. The material properties of
grey cast iron are:
Density- 7100 kg/m3 Young
modulus- 125 GPa
Poisson’s ratio- 0.25 Specific
heat- 586 J/Kg.K
Thermal conductivity- 54 W/m.K