Claims
- 1. A method for forming non-circular pipes having different sectional shapes along a longitudinal direction thereof, comprising:
- providing a raw pipe between upper and lower dies;
- sealing ends of the raw pipe;
- applying an internal pressure within the sealed pipe;
- while maintaining at least said internal pressure, actuating at least one of said upper and lower dies to apply a load to said raw pipe in a direction perpendicular to said longitudinal direction to form an intermediate pipe having an intermediate section with a non-circular cross-section, wherein said intermediate section has a lower surface which is substantially flat; and then
- removing a portion of said intermediate pipe at said intermediate section to form two non-circular pipes.
- 2. A gas turbine part comprising a non-circular pipe formed by a method according to claim 1, wherein one end surface of said non-circular pipe exhibits a circular shape, the other end surface exhibits a substantially rectangular shape, and respective sections between the one end surface and the other end surface continuously changes from the circular shape to the substantially rectangular shape.
- 3. A gas turbine in which said gas turbine part according to claim 2 is used as a passage for conducting the gas burnt in a combustion chamber to a turbine.
- 4. A method according to claim 1, wherein the raw pipe has a circular cross-section.
- 5. A method according to claim 1, comprising a further step of providing said raw pipe with a circular cross-section along its entire length with a central section having a larger diameter than end sections.
- 6. A method according to claim 5, wherein said central section is provided with the larger diameter by applying an internal pressure to said raw pipe and expanding said central section to a predetermined contour.
- 7. A method according to claim 1, further comprising heat treating the intermediate pipe.
- 8. A method according to claim 1, wherein no axial tensile force is applied to said raw pipe during forming, whereby tensile strain in the axial direction is reduced.
Priority Claims (1)
Number |
Date |
Country |
Kind |
6-224763 |
Sep 1994 |
JPX |
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Parent Case Info
This application is a continuation application of Ser. No. 08/529,981 filed Sep. 19, 1995, now abandoned.
US Referenced Citations (2)
Non-Patent Literature Citations (2)
Entry |
Japanese Patent Unexamined Publication No. 55-77934 Date Jun. 1980. |
Japanese Patent Uenxamined Publication No. 55-55819 Date Apr. 1980. |
Continuations (1)
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Number |
Date |
Country |
Parent |
529981 |
Sep 1995 |
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