Cast components and manufacture and use methods
A method comprises: providing a spiral metallic workpiece having a cast structure associated with such spiral; and at least partially flattening the workpiece.
1. A method comprising:
casting a metallic workpiece having a spiral gap wherein the spiral gap is formed in the casting step; and
at least partially flattening the workpiece by unrolling.
2. The method of claim 1 wherein:
the metallic workpiece has a single crystal (SX) structure.
3. The method of claim 1 wherein:
the metallic workpiece has a modified single crystal (SX) structure characterized by a progressively circumferentially varying crystallographic orientation.
4. The method of claim 1 wherein:
the spiral of the spiral gap is about an axis within 5° of a <001> or <111> direction of the workpiece.
5. The method of claim 1 wherein:
the metallic workpiece is a right circular cylinder with said spiral gap.
6. The method of claim 1 wherein:
the metallic workpiece is a hollow right circular cylinder with said spiral gap.
7. The method of claim 1 wherein:
the workpiece is a nickel-based superalloy.
8. The method of claim 1 further comprising:
securing ends of the workpiece to each other or to ends of other similar workpieces so as to form a full hoop.
9. The method of claim 8 wherein:
the securing comprises welding.
10. The method of claim 1 wherein the casting comprises withdrawing from a furnace in a direction within 1° of parallel to an axis of the spiral of the spiral gap.
11. The method of claim 1 wherein the casting comprises forming a mold by shelling a spiral core.
12. The method of claim 11 further comprising forming the spiral core by bending a refractory metal sheet and ceramic coating the sheet.
13. The method of claim 11 further comprising forming the spiral core by rolling into a spiral a sandwich of a cloth sheet and wax.