SPF/DB Gas needle improvement
AssigneeRockwell International Corporation
InventorsSeb R. Sarkisian, George W. Stacher, Arthur Martinez
Life of this patent
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Abstract
Dummy needles are used for preventing closure of gas-conveying passageways communicating the interior, and provided at the peripery, of a multi-sheet stack of titanium alloy materials during diffusion bonding. After the diffusion bonding has been carried out, the dummy needles fitted within the passageways are removed, the passageways are reamed out to ensure their circular shape, and needles adapted for superplastic forming are inserted into the newly reamed passageways.
Claims7
A method for preventing crushing of passageways terminating at the periphery of a stack of sheets of titanium aluminide material during diffusion bonding of said stack within a protective retort, the passageways extending into and through the interior of the stack for fluidly communicating said interior with a source of gas located outside said stack for effecting superplastic forming following said diffusion bonding, said method comprising:
- inserting a dummy needle within each of said passageways at said stack periphery such that one end of said needle is lodged within said passageway and the opposite, free and extends outwardly of said passageway beyond the periphery of said stack;
- disposing a crush-proof housing adjacent the free end of each of said needles so that said free end is maintained in a protected state during diffusion bonding, and
- replacing said dummy needles after completion of said diffusion bonding with conventional needles for use in effecting superplastic expansion of said diffusion bonded stack during said subsequently performed superplastic forming process.
In a stack of sheets of titanium alloy materials including gas-conveying circular passageways extending from the interior of the stack to the ambient, a method of using dummy needles to maintain the circular shape of said passageways, comprising:
- inserting a dummy needle in each stack passageway,
- performing diffusion bonding
- removing the dummy needles
- reaming out said each passageway to ensure a circular shape;
- and
- fitting said each reamed out passageway with needles adapted for superplastic forming.
Dependencies are inferred from the claim text.