US2004031140A1PendingUtilityA1
Methods for salvaging a cast article
Priority: Dec 23, 1996Filed: Aug 11, 2003Published: Feb 19, 2004
Est. expiryDec 23, 2016(expired)· nominal 20-yr term from priority
B23K 20/021Y02T50/60F01D 5/005B23P 15/02Y10T29/49975C23C 4/18C23C 4/01B23P 2700/06C23C 4/00F01D 5/288B23P 6/007
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Claims
Abstract
A method of salvaging a cast article by correcting the dimensional characteristics of the cast article and forming a protective coating. The dimensional differences are determined between pre-repair cast article dimensions and desired post repair cast article dimensions to correct a casting defect in the article. The determination may be made by determining the location and approximate volume of a void in the surface of the article. The determination may also be made by determining an amount of buildup volume required to make at least a portion of the surface of the cast article built up to the desired post repair dimensions. The article is coated in at least an area of the casting defect with a high-density coating material capable of forming a diffusion boundary between the coating material and the article. The coating material may comprise an alloy with substantially no oxide forming constituents so as to avoid the formation of oxide inclusions in the coating material. The coating material may be applied using a coating process that is effective to create a coating on the surface of the article that will be diffusion bonded to the article after the hot isostatic heat treatment. The hot isostatic heat treatment process is performed to form the diffusion boundary between the coating material and the article
Claims
exact text as granted — not AI-modified1 ) A method of correcting the dimensional characteristics of a cast article, comprising the steps of:
Determining dimensional differences between pre-repair cast article dimensions and desired post repair cast article dimensions to correct a casting defect in the article; Coating the article in at least an area of the casting defect with a high-density coating material capable of forming a diffusion boundary between the coating material and the article; and Performing a hot isostatic heat treatment process to form the diffusion boundary between the coating material and the article.
2 ) A method of correcting the dimensional characteristics of a cast article according to claim 1; further comprising the step of removing material in an area of the casting defect before the step of coating the article.
3 ) A method of correcting the dimensional characteristics of a cast article according to claim 1; wherein the casting defect being caused by at least one of an inclusion at a surface of the article, an air bubble at the surface of the article, undercasting, a void and shrinkage
4 ) A method of correcting the dimensional characteristics of a cast article according to claim 1; further comprising the step of performing a sintering heat treatment before the step of performing the hot isostatic heat treatment to limit the occurrence bubbles on the surface of the coating material after an isostatic heat treatment.
5 ) A method of correcting the dimensional characteristics of a cast article according to claim 4; wherein the sintering heat treatment is performed at a temperature substantially the same as the temperature of the hot isostatic heat treatment.
6 ) A method of correcting the dimensional characteristics of a cast article according to claim 1; wherein the coating material comprises an alloy with substantially no oxide forming constituents so as to avoid the formation of oxide inclusions in the coating material.
7 ) A method of correcting the dimensional characteristics of a cast article according to claim 6; wherein the coating material comprises:
Element
Percentage
Nickel
Balance
Chromium
9.0
Cobalt
10.0
Carbon
0.14
Molybdenum
8.6
Tungsten
12.5
Boron
0.015
Columbium
1.0
8 ) A method of applying a protective coating to a metal article, comprising the steps of:
Providing a metal article; Coating the metal with a high-density coating material capable of forming a diffusion boundary between the coating material and the article, the coating material comprising an alloy with substantially no oxide forming constituents so as to avoid the formation of oxide inclusions in the coating material; and Performing a hot isostatic heat treatment process to form the diffusion boundary between the coating material and the article whereby the substantially oxide free coating and the diffusion boundary provide a protective coating to protect the article from damage.
9 ) A method of applying a protective coating to a metal article according to claim 8; further comprising the step of performing a sintering heat treatment before the step of performing the hot isostatic heat treatment to limit the occurrence bubbles on the surface of the coating material after an isostatic heat treatment.
10 ) A method of applying a protective coating to a metal article according to claim 9; wherein the sintering heat treatment is performed at a temperature substantially the same as the temperature of the hot isostatic heat treatment.
11 ) A method of applying a protective coating to a metal article according to claim 8; wherein the coating material comprises an alloy with substantially no oxide forming constituents so as to avoid the formation of oxide inclusions in the coating material.
12 ) A method of applying a protective coating to a metal article according to claim 11; wherein the coating material comprises:
Element
Percentage
Nickel
Balance
Chromium
9.0
Cobalt
10.0
Carbon
0.14
Molybdenum
8.6
Tungsten
12.5
Boron
0.015
Columbium
1.0
13 ) A method of repairing a turbine engine airfoil part, comprising the steps of:
Determining dimensional differences between pre-repair airfoil dimensions of a turbine engine airfoil part substrate and desired post repair airfoil dimensions of the turbine engine airfoil part substrate, the pre-repair airfoil dimensions having different airfoil characteristics than the post-repair aifoil dimensions, the turbine engine airfoil part being comprised of a metal alloy; Coating the engine airfoil part with a coating capable of forming a diffusion boundary with the turbine engine airfoil part substrate, the coating material comprising an alloy with substantially no oxide forming constituents so as to avoid the formation of oxide inclusions in the coating material; and Performing a hot isostatic heat treatment process to obtain a post-repair turbine engine airfoil part having the desired post-repair dimensions and having a substantially oxide free coating and diffusion bonding between the coating material and the turbine engine airfoil part substrate to provide a protective coating to protect the article from damage.
14 ) A method of repairing a turbine engine airfoil part according to claim 13; further comprising the step of performing a sintering heat treatment before the step of performing the hot isostatic heat treatment to limit the occurrence bubbles on the surface of the coating material after an isostatic heat treatment.
15 ) A method of repairing a turbine engine airfoil part according to claim 14; wherein the sintering heat treatment is performed at a temperature substantially the same as the temperature of the hot isostatic heat treatment.
16 ) A method of applying a protective coating to a metal article according to claim 13; wherein the coating material comprises:
Element
Percentage
Nickel
Balance
Chromium
9.0
Cobalt
10.0
Carbon
0.14
Molybdenum
8.6
Tungsten
12.5
Boron
0.015
Columbium
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