MANUFACTURE OF COMPOSITE TURBINE ROTORS

摘要

D-3005 C-3115 A method for manufacturing a turbine rotor assembly from dissimilar materials to produce a hybrid composite rotor including the steps of: preforming a hub disc of a controlled outer diameter and prefabricating a ring of airfoils including a machine slotted fixture ring of mild steel slotted to receive airfoils inserted therein; and wherein the method further includes the steps of grinding the internal diameter of the mild steel ring to expose the airfoil bases to locate them at a radius line which will correspond to the outer diameter of the hub disc rim to maintain a pressure fit relationship therebetween when the ring of airfoils is pressed or shrunk on the outer diameter of the disc and thereafter sealing exterior joint lines between the mild steel fixture ring, airfoils and hub disc to form a pressure sealed surface on the exterior of the joined parts; subjecting the full outer planar extent of the pressure sealed configuration to an elevated pressure while maintaining it under an elevated temperature to produce a hot isostatic bonding of the base of each of the airfoils against the controlled outside diameter of the hub disc for a time period to produce a diffusion bonded metallurgical joint between the parts; and thereafter removing the mild steel fixture ring from the joined parts by dissolving it in a pickling solution thereby to define precision flow passages between facing surfaces of the airfoils and the hub surface of the disc.