Rolls-royce Corporation

Anthony L Pratt

James E Boardman

Bryan L Benn

Arnold J Pratt

A method of making a bladed disc assembly, of a kind used, for example, in the turbine or compressor sections of a gas turbine engine, includes forming a peripheral groove in the rim of the disc, positioning a plurality of bladed segments around the disc, each segment preferably including two or more blades extending radially from a root portion, each segment having its root portion located in the groove, securing the root portions in the groove by means of electron beam welding to form circumferential seam welds at either side of the root portions and axial seam welds between the root portions of adjacent segments thereby forming a vacuum seal, and diffusion bonding the root portions and the rim of the disc by means of isostatic hot gas pressure bonding.

Bladed disc assembly method by hip diffusion bonding

A method of making a titanium fan disc for a gas turbine engine comprises the steps of providing a pair of identical forged titanium cylinders each having a central bore and a flat end surface at right angles to its central axis, preparing the flat end surface of each cylinder to a high degree of smoothness, abutting the prepared surfaces of the cylinders one against the other in axial alignment, removing air from between said surfaces, and diffusion bonding the cylinders end-to-end by hot isostatic pressing to form the disc.

Diffusion bonding turbine fan disc

An electron beam welding apparatus in which the beam deflection coils controlling the weld may be modified by the superimposition of a variable input voltage so as to control the fade-out slope of the welding region.

Electron beam welding

Two titanium alloy turbine components are diffusion bonded together by preparing mating surfaces of the components to a high degree of smoothness, putting the surfaces in mating abutment, placing the components within a yoke in a vacuum furnace, evacuating the furnace, increasing the temperature of the furnace to about 960.degree. C., applying pressure across the interface between the components by means of a pressure bag between the yoke and the components, maintaining the vacuum, temperature and pressure for about 30 minutes, back filling the furnace with argon, increasing the pressure of argon to about 1000 atmospheres, maintaining that pressure and temperature for about two hours, and then reducing the pressure to atmospheric and removing the diffusion bonded components from the furnace.

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Bristol, United Kingdom

Anthony L Pratt