Investment casting pin and method of using same

Patent metadata

Field	Value
Publication number	US-11179769-B2
Application number	US-201916271293-A
Country	US
Kind code	B2
Filing date	Feb 8, 2019
Priority date	Feb 8, 2019
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

A method of forming a component by investment casting includes disposing at least a portion of an investment casting pin within a core. The investment casting pin includes a ceramic base pin having a perimeter and a length extending perpendicular to the perimeter and a sacrificial coating disposed about the perimeter of the ceramic base pin along at least a portion of the length of the ceramic base pin. A metal casting is formed around the core. The core and the sacrificial coating are leached with a leaching solution and the investment casting pin is removed from the metal casting.

First claim

What is claimed is:

1. A method of forming a component by investment casting, the method comprising:
disposing at least a portion of an investment casting pin within a core, the investment casting pin comprising a ceramic base pin having a perimeter and a length extending perpendicular to the perimeter and a sacrificial coating disposed about the perimeter of the ceramic base pin along at least a portion of the length of the ceramic base pin;
forming a metal casting around the core;
leaching the core and the sacrificial coating with a leaching solution, the ceramic base pin being resistant to leaching by the leaching solution; and
manually removing the investment casting pin from the metal casting subsequent to leaching at least a portion of the sacrificial coating with the leaching solution, wherein the ceramic base pin is made of alumina.

2. The method of claim 1 , wherein the component is an airfoil.

3. The method of claim 1 , wherein the sacrificial coating is configured to be removed from the ceramic base pin, at least in part, in the presence of a leaching solution.

4. The method of claim 1 , wherein the sacrificial coating is a silica coating.

5. The method of claim 1 , wherein the sacrificial coating is disposed about the perimeter of the ceramic base pin along the entire length of the ceramic base pin.

6. The method of claim 1 , wherein the perimeter of the investment casting pin defines a passage through at least a portion of the metal casting.

7. The method of claim 6 , wherein at least a portion of the leaching solution flows through the passage when leaching the core.

8. The method of claim 1 , wherein the metal casting is made of a single-crystal alloy.

9. The method of claim 1 , wherein a first portion of the sacrificial coating has a first thickness and a second portion of the sacrificial coating has a second thickness which is different than the first thickness.

10. The method of claim 1 , wherein the sacrificial coating is disposed about the perimeter of the ceramic base pin along a second length which is less than the length of the ceramic base pin.

11. A method of forming a component by investment casting, the method comprising:
disposing at least a portion of an investment casting pin within a core, the investment casting pin comprising a ceramic base pin having a perimeter and a length extending perpendicular to the perimeter and a sacrificial coating disposed about the perimeter of the ceramic base pin along at least a portion of the length of the ceramic base pin;
forming a metal casting around the core, the investment casting pin defining a passage within the metal casting;
leaching the core and the sacrificial coating with a leaching solution without leaching the ceramic base pin;
directing at least a first portion of the leaching solution into the metal casting in a first direction, through the passage between the ceramic base pin and the metal casting, and a second portion of the leaching solution into the metal casting in a second direction, different than the first direction; and
removing the investment casting pin from the metal casting,
wherein the ceramic base pin is made of alumina.

12. The method of claim 11 , wherein the sacrificial coating is a silica coating.

13. The method of claim 11 , wherein the sacrificial coating is disposed about the perimeter of the ceramic base pin along the entire length of the ceramic base pin.

14. The method of claim 11 , wherein a first portion of the sacrificial coating has a first thickness and a second portion of the sacrificial coating has a second thickness which is different than the first thickness.

15. The method of claim 11 , wherein the sacrificial coating is disposed about the perimeter of the ceramic base pin along a second length which is less than the length of the ceramic base pin.

Assignees

• United Technologies Corp
• Raytheon Tech Corp

Inventors

• Bullied Steven J
• Beers Russell A
• Bochiechio Mario P

Classifications

• B22C21/14 Primary

  for reinforcing or securing moulding materials or cores, e.g. gaggers, chaplets, pins, bars · CPC title

• B22C7/02

  Lost patterns · CPC title

• B22D29/002

  by leaching, washing or dissolving · CPC title

• B22C9/04

  Use of lost patterns · CPC title

• B22C9/10

  Cores; Manufacture or installation of cores {(breaker cores B22C9/084)} · CPC title