United Technologies Corporation

Bryant H Walker

Donald G MacNitt, Jr

Raymond M Walker

Steven D Jenkel

Ralph B Bogard

William D Carruthers

A method is taught for the isostatic forging of integrally bladed rotors, in which deformable hollow single crystal blades are protected from deformation during diffusion bonding to the disk by encapsulation in a ceramic protective shell. The ceramic shell serves to occupy the areas between the blades and the surrounding forging die set, so that during application of high temperatures and pressures, damage to the blades is prevented without the use of complex segmented die assemblies.

Integrally bladed rotor fabrication

A die package for forming a central disc structure having a plurality of integrally formed appendages extending therefrom includes a cylindrical array of appendage forming, abutting die segments which are prevented from tilting or moving in a circumferential direction by means of pins extending into slots formed along the parting lines between abutting die segments in the upper surfaces of the segments. In one embodiment, the pins extend upwardly from between opposed, parallel, radially and axially extending walls of each slot and fit tightly between said walls. The upper ends of the pins are secured to a rigid annular ring overlying the slots. The slots extend radially inwardly of the pins to allow the die segments to be moved radially outwardly after forging to release the forging from the die package.

Forging die package

A die package for forging a central disc structure having a plurality of integrally formed appendages extending radially outwardly therefrom includes a circumferential array of abutting die segments defining a central cavity within the array and appendage forming cavities between the segments. Each die segment has a locating hole in its upper surface, and an annular support member overlies the holes and has a plurality of locating holes therein, one hole corresponding to each hole in said die segments. A non-metallic rod, such as a glass rod, is disposed tightly within and extends between each pair of aligned holes, thereby locating the die segments accurately relative to each other and to a central axis of the die package. The rods are shearable at elevated temperatures to enable radial movement of the die segments after forging for releasing the forged component from the die package.

Forging method and die package therefor

A component, such as a turbine disk, made from a metal or metal alloy which has been processed to display superplastic properties at elevated temperatures, is diffusion bonded to a component or components, such as turbine blades, made from another metal or metal alloy, by disposing the components in a press with the surfaces to be bonded in mating contact. Moisture and oxygen are removed from between the surfaces. Heat and pressure are then applied, such as by forging at an elevated temperature or by hot isostatic pressing, to cause superplastic deformation of at least one of the components at the bonding surfaces. The heat and pressure are held sufficiently long to diffusion bond the surfaces. The new integral assembly is then heat treated to obtain desired properties. Consistently good diffusion bonds are achieved by this method.

Process for fabricating multi-alloy components

The present invention provides methods and apparatus improving the dimensional accuracy of forged components. Uniformity of like component details is sought and a specific object is to provide a die package for forming closely toleranced appendages integrally with a central disk structure from which the appendages extend. In one effective embodiment incorporating concepts of the present invention, the forging dies include a stationary die and a movable die comprising at least two separately movable elements which are mounted on a common axis with the stationary die. A plurality of arcuate die segments are adjacently placed in cylindrical array about the stationary and movable dies. The arcuate die segments form cavities of the inverse geometry of the appendages to be formed and in at least one embodiment are interlocked to prevent tilting of the segments in the die package. The movable die elements are sequenceable to form a billet of material into a workpiece having an intermediate configuration, and subsequently into a workpiece of final configuration. In at least one embodiment, pressure pads are disposed against one of the movable dies to prevent displacement of that die by the billet material as the intermediate configuration is formed.

Forging method and apparatus

Forging apparatus

The present invention provides a technique for improving the dimensional accuracy of forged components. Uniformity of like component details is sought and a specific object is to provide a die package for forming closely toleranced appendages integrally with a central disk structure from which the appendages extend. In one effective embodiment incorporating concepts of the present invention, the forging dies include a stationary die 26 and a moveable die 28 which are mounted on a common axis and a plurality of arcuate die segments 30 which are adjacently placed in cylindrical array about the stationary and moveable dies. The arcuate die segments form cavities of the inverse geometry of the appendages to be formed and are interlocked to prevent tilting of the segments in the die package. A collar 40 extends from the stationary die to interlocking engagement with a channel 46 in the inwardly facing surface of each arcuate die segment.

Die assembly for use in forging operation

A forging apparatus has an upper die and lower die with the lower die being positioned on a die stack with the upper die being movable by a ram, said upper and lower dies having cylindrical portions extending towards each other where the rim of the formed disc is to be located. Blade dies are positioned around the radial opening presented between the two faces of the upper and lower die as they rest on a preformed blank, said cylindrical array of blade dies being held in position by two wires around their outer circumference and supported in the forging operation by a cylindrical back-up die; the cylindrical array of blade dies being slanted outwardly at its upper and lower edge from where they engage the cylindrical portions, forming an upper and lower annular cam surface. Ring members are positioned around both of said cylindrical sections for slidable movement thereon, said ring members being of wedge-shape cross-section so that as they are moved inwardly, when they contact said cam surfaces, they will cam said blade dies radially outward. Actuating pins extend from each of said ring members to a location above and below their respective upper and lower dies where they can be actuated by spider arms fixed to an actuating shaft which extends through their respective ram or die stack. Knockout pins are located in the upper and lower dies and are actuated by rods extending through each of the actuating shafts.

Forging apparatus having means for radially moving blade die segments

A rotor for a gas turbine engine has a wrought superalloy disk with ceramic blades. The rotor is formed by placing ceramic blades in a fixture with their ceramic blade roots extending inwardly and between the upper and lower rims of a disk or disk halves. The facing upper and lower circumferential rims are cut away to provide for the ceramic blade roots. Said disk or disk halves being of a wrought superalloy having a fine grain size microstructure which can be placed in a superplastic condition. A compliant layer material is placed between the ceramic blade roots and the rims of the disk, and the disk and compliant layer are then heated so as to place the disk in a superplastic condition and pressed into intimate contact with the ceramic blade root, and if disk halves are being used, they are bonded together at inner mating surfaces. The rotor is then heat treated to return the disk to its normal condition of high strength and hardness. The compliant layer can be a thin layer of material inserted between the blade root and disk, or it can be a material applied directly to the blade root or disk slot such as by plating, sputtering, or flame spraying.

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Stuart, FL, United States of America

Bryant H Walker