Single-cast, high-temperature, thin wall structures and methods of making the same

A method of making a multi-wall alloy structure comprising:

• providing a main core corresponding to a void in said structure;
• providing a first removable pattern material covering said main core corresponding to a first wall of said structure;
• providing a thin core having a density greater than 70 percent in fixed relationship to said main core so as to correspond to a thin passageway in said structure;
• providing a second removable pattern material covering said thin core so as to correspond to a thin wall in said structure having a thickness of less than 0.03 inches;
• surrounding said second removable pattern with a casting mold so as to define the outer surface of said thin wall;
• removing said patterns to leave said cores in fixed relationship with each other and said casting mold;
• charging said casting mold with molten alloy and varying the charge pressure with time so that said thin wall is formed without causing said casting mold to creep;
• solidifying said molten alloy and removing said casting mold and said cores to provide said multi-wall alloy structure.

A method comprising:

• providing a main ceramic core;
• covering said main ceramic core with a first pattern where an alloy is to be cast;
• placing a very thin core on said pattern, said thin core having a thickness less than about 0.02 inches and a density greater than about 70 percent, and said thin core positioned to have a curved shape;
• providing a hole through said curved thin core, first pattern and into said main core to form a pocket in said main core to receive a portion of a first narrow rod;
• inserting a portion of a rod through said thin core so that the longitudinal axis of said rod and the outer surface of said thin core away from said main core are at substantially right angles, through said first pattern and so that a portion of said rod is firmly received in said pocket formed of said main core;
• covering said thin core with a second pattern where an alloy is to be cast;
• providing a hole through said second pattern and into said thin core but not extending therethrough to provide an angled pocket in said thin core for receiving a second rod at a predetermined position where force is needed to keep said thin core in a position such that said thin core has a curved shape;
• inserting a second rod in the hole in said second pattern and so that said second rod is received in the pocket of said thin core;
• surrounding said second pattern with a casting mold so that said casting mold carries one end of said second rod and so that upon removing said patterns said cores are held in a fixed relationship to each other and said casting mold, and said curved thin core retains its shape.

A process of casting a molten alloy into a substantially long mold cavity defined at least partially by a ceramic shell, so that the ceramic shell defining the mold cavity is not substantially distorted and the mold cavity is not substantially expanded during the casting process comprising

• charging molten alloy into a mold reservoir which communicates with a charge line and a mold cavity defined by a ceramic shell wherein the amount of molten alloy charged into the reservoir is sufficient for the molten alloy to flow by gravity from the reservoir through the charge line and to completely fill the mold cavity;
• bleeding off molten alloy at a location above the mold cavity though a bleed line having a control orifice therein so that the alloy pressure in the mold cavity is decreased over time and so that the ceramic shell is not substantially distorted and the mold cavity is not substantially expanded during the casting process;
• and
• solidifying the molten alloy to produce a solid metal part having dimensions corresponding to the mold cavity.