Rohr Industries, Inc.

Rohr, Inc.

USA As Represented by Secretary of the Navy

Gilbert C Cadwell

Paul M Phillips

A vertically reciprocable lower chamber has a ceramic forming chamber surrounded by a steel reinforcing jacket. A fixed upper chamber includes a metal cover surrounded by ceramic insulator blocks and and an outer steel jacket. A horizontal foam ceramic platen inside the steel cover has a serpentine radiant heating coil attached to the flat underside thereof via inserted fasteners for more efficient heating of a metal sheet positioned horizontally between the upper and lower chambers. A plurality of foam ceramic insulator blocks have secondary heating coils attached to their inwardly facing surfaces for heating the peripheral edges of the metal sheet. This ensures a gas tight seal between the metal cover and the sheet.

Cold wall superplastic forming press with surface mounted radiant heaters

An SPF press is capable of forming large generally cylindrical structures from a sheet made of a first metal such as Titanium. The sheet is first rolled into a cylindrical or conical part blank. The press has a generally cylindrical ceramic die with a surface defining the contour of a part to be formed. The part is formed by pressing a first side of the part blank against the die utilizing high pressure gas. Generally cylindrical gas impervious seals overlie the opposite ends of the cylindrical part blank on a second side thereof opposite the first side. Each of these gas impervious seals includes a support member and a seal member which are spaced apart to define a gap therebetween. A generally cylindrical seal ring is seated in each gap and contacts the second side of the cylindrical part blank. The seal rings are made of a second metal that is softened at a temperature at which the first metal becomes superplastic. This allows the seal rings to deform and provide a substantially gas impervious seal to prevent high pressure gas introduced against a medial portion of the cylindrical part blank from escaping to the ends of the part blank.

Apparatus for superplastic forming of large cylindrical structures

A method and apparatus for superplastic and diffusion bonding of hollow metal parts which are generally surfaces of rotation. A hollow frangible ceramic die having an interior shaping surface is provided. A metal part to be shaped is placed against the shaping surface (together with any other metal components to be diffusion bonded to the part during forming) and the remainder of the die is covered with sheet metal pieces, all of which are sealed together and to the part to form a gas-tight enclosure for the die. The enclosure is flushed with an inert gas and/or evacuated through an opening in the enclosure. The assembly is placed in an autoclave and exposed to an appropriate pressure and temperature to superplastic form the part outwardly against the shaping surface. The assembly is cooled and removed from the autoclave, then the enclosure is removed. The die is broken away, freeing the formed part.

Method and apparatus for superplastic forming of hollow parts

A pair of sheets of a metal capable of exhibiting superplasticity, such as Titanium, are placed in overlapping relationship and the peripheral edges of the sheets are joined, such as by welding, to provide a gas impervious seal. The joined metal sheets are lowered into a press so that they extend vertically between a pair of horizontally spaced apart, vertically extending preheated ceramic dies. The dies are previously transferred inside insulating shrouds from a preheater station before being loaded into the press. At least one of the dies is moved horizontally toward the other one of the dies so that the joined metal sheets are positioned closely adjacent to the dies. As a result, the metal sheets are heated to a predetermined temperature at which they are capable of exhibiting superplasticity. Thermostatically controlled heating platens behind the dies offset any heat losses in the dies as they radiate energy to the joined metal sheets. Thereafter a pressurized gas, such as Argon, is introduced between the joined metal sheets so that they are pushed outwardly against corresponding ones of the dies and formed against the same. At least one of the dies is thereafter moved horizontally away from the other one of the dies and the formed metal sheets are lifted out of the press. The formed metal sheets are then transferred to a cooling station. Once cooled, the formed metal sheets are cut apart to produce two or more formed pieces.

Method and apparatus for dual superplastic forming of metal sheets

A clamping method and apparatus for applying the necessary pressure to an sembly of metal parts during diffusion bonding and/or superplastic forming of the parts. Basically, the apparatus comprises a pair of opposed generally L-shaped frames having a cavity therebetween for holding the assembly of parts and associated shaping tooling. The frames are pivotable about a hinge connecting first ends, with a mechanism at the opposite ends for moving the frames together in a clamping manner or apart to allow access to the cavity. The tooling within the cavity typically includes a pressure vessel having a housing containing ceramic forming members having an internal volume within which metal parts to be shaped and/or bonded are placed. The parts are subjected to heat and pressure during processing. This apparatus and method are particularly suitable for manufacturing elongated metal products having a generally box-like cross section.

Method and apparatus for clamping large assemblies for diffusion bonding

A method and apparatus for superplastic forming and diffusion bonding of hollow metal parts. A forming assembly is prepared by surrounding a hollow tool (typically having a frusto-conical exterior) with a part blank having a corresponding shape, attaching parts, such as rings, to the exterior of the blank, then surrounding those parts with a skin blank. The forming assembly is placed in a pressure chamber, a heater is placed within the assembly and the chamber is sealed. The assembly of parts is heated to the diffusion bonding temperature of the parts while subjecting them to high gas pressure. The skin blank is deformed into intimate contact with the adjacent surfaces of the other parts and all of the parts are diffusion bonded together at all interfaces to form a unitary product. Gas pressure is released and the product is cooled and removed from the chamber and hollow tool. Any desired finish machining is accomplished and the productive is complete.

Method and apparatus for superplastic forming and diffusion bonding of

An improved method of superplastic forming comprises the steps of selecting a relatively larger driver sheet and a relatively smaller part blank, both being made of Titanium, Titanium alloy or other metal capable of exhibiting superplasticity. A ceramic die is placed on a bottom wall of an upwardly opening ceramic forming chamber having sidewalls with upper edges. The ceramic chamber has an outer supporting steel jacket. The part blank is positioned over the die. The driver sheet is positioned over the part blank so that the peripheral edges of the driver sheet rest on the upper edges of the sidewalls of the forming chamber. A cover is provided for closing the chamber. It has a peripheral seal extending from an underside thereof. The cover and the chamber are clamped together in order to impinge the seal into a periphery of the driver sheet. The driver sheet and part blank are then heated to a predetermined temperature at which they exhibit superplasticity. Next a pressurized inert gas is introduced into an interior formed by the closed cover and chamber and thereafter released so that the driver sheet presses and forms the part blank around the die. The peripheral edges of the part blank are free to draw in during the forming to thereby avoid any undesired necking or thinning. The cover is lifted from the chamber and the formed driver sheet and part blank are removed.

Superplastic drape forming

A method and apparatus for forming and bonding metal assemblies using an internally heated chamber. The parts can be both superplastic formed and diffusion bonded to other parts. A closable chamber contains a heating element near the chamber center. A ceramic die at least partially surrounding the heating element has a forming surface toward the heating element. The inner wall of the chamber is lined with a pressure bladder. A granular material, conical ceramic support, or extensible bladder fills the space between ceramic die and chamber inner wall. With the chamber closed, the heater is activated while an inert gas under pressure is introduced between heater and die and the bladder if used is pressurized. The bladder or packed granules support the outer die surface while the gas pressure presses metal parts on the die forming surface against the die. The metal parts are formed and bonded together by the substantially isostatic forces thereon. The heat is concentrated on the parts, leaving the chamber walls cold. When forming is complete, the chamber interior is cooled and the die is removed and broken away from the formed assembly. Parts can be formed and bonded rapidly with a considerable energy saving over conventional isostatic pressing ovens.

Method and apparatus for forming and bonding metal assemblies

A rotating die system for cold forming of sheet metal wherein a male die rotates relative to both an hydraulically supported resilient diaphragm backing the sheet metal blank and the driving force on the male die. The male die is pivotly connected to both a draw ring and the transmitted driving force. A sheet of metal to be formed is held in place on the upper surface of a draw ring die over a forming aperture. The male die is caused to rotate within the aperture against the sheet metal to accomplish the desired forming.

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Lakeside, CA, United States of America

Gilbert C Cadwell