1.1 This specification covers vacuum-treated carbon and alloy steel forgings for turbine rotors and shafts. 1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The valu This specification covers vacuum-treated carbon and alloy steel forgings for turbine rotors and shafts. Materials shall be manufactured and treated by: melting process via basic electric-furnace; secondary melting process via electrode-electroslag or v