Method of forging spinel domes
AssigneeRaytheon Company
InventorsEdward A. Maguire, Richard L. Gentilman
Life of this patent
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Abstract
A method of forging spinel into complex shapes in which a spinel plate is placed in a mold while the spinel plate is heated, in an atmosphere of helium, to a temperature below its melting point and above its solid two phases transition point that allows plastic deformation to take place. Forging stresses well above the yield point of the spinel are applied to the plate by the mold to reduce the forging time.
Claims15
A method of comprising the steps of:
- placing a plate of spinel between two portion of a mold, said two portions having complementary shapes for forming a cavity of a predetermined complex shape;
- the composition of said spinel comprising a ratio of Al.sub.2 O.sub.3 :MgO in the range of greater than 1:1 to 3.5:1;
- heating said spinel to a temperature in the range below its melting point and above its single phase transition point;
- and
- applying a pressure to said mold for producing compound stresses in said spinel plate to plastically deform said spinel plate to the complex shape of the mold cavity.
A method comprising the steps of:
- forming an alumina-rich plate having a ratio of Al.sub.2 O.sub.3 :MgO in the range of greater than 1:1 to 3.5:1;
- placing said spinel plate over a lower portion of a mold having a cavity of a predetermined shape;
- placing a top portion of said mold over said spinel plate in mating relationship with said lower portion and preventing said top portion from applying significant pressure;
- heating said spinel plate to a forging temperature below its melting point at which plastic deformation of said spinel plate can take place;
- said forging temperature having a value higher than the phase transition point of said spinel for substantially preventing a change in said spinel from a single phase to a two-phase state;
- applying a pressure to said mold exceeding the yield stress in at least one portion of said spinel plate but not reaching the fracturing point of spinel;
- and
- said pressure and said mold shape producing compound stresses in said spinel plate.
The method of hot forging a plate of alumina-rich spinel, having a ratio of Al.sub.2 O.sub.3 :MgO in the range of slightly over 1:1 to 3.5:1, into a complex shape comprising the steps of:
- placing said plate over a first portion of a mold, said first portion having a cavity therein substantially defining a first complex surface;
- placing a second portion of said mold over said spinel plate without causing said second portion to exert significant pressure on said plate, said second mold portion having a second complex surface and being capable of mating with said first mold portion;
- heating said spinel plate to a forging temperature below its melting point and within the temperature range in which said spinel can exist in its solid angle phase and at which plastic deformation can readily take place;
- and
- applying pressure to said mold for producing compound stresses in portions of said spinel plate that cause said spinel plate to conform to the first and second complex surfaces of said mold, said forging temperature and stresses having values producing a minimum temperature in said spinel plate higher than the transition point of said spinel for substantially keeping said spinel in its single phase state.
Dependencies are inferred from the claim text.