Methods for repairing and reclassifying gas turbine engine airfoil parts

29 Pages·2013·2.44 MB·English

US006049978A
United States Patent
[19] [11] Patent Number: 6,049,978
Arnold [45] Date of Patent: Apr. 18, 2000
[54] METHODS FOR REPAIRING AND [57] ABSTRACT
RECLASSIFYING GAS TURBINE ENGINE _ _ _ _ _ _
AIRFOIL PARTS A method for repairing gas turbine engine airfoil parts. The
dimensional differences betWeen pre-repaired dimensions of
[75] Inventor; James E_ Arnold, New Haven, Conn a turbine engine airfoil part and desired post-repair dimen
sions of the turbine engine airfoil part are determined. A
[73] Assignee; Recast Airfoi] Group, North Haven, build-up thickness of coating material required to obtain the
Conn desired post-repair dimensions of the turbine engine airfoil
part is determined. A high-density coating process, such as
_ HVOF, is used to coat the turbine engine airfoil part With a
[21] Appl' NO" 09/143,643 coating material to the determined build-up thickness of
[22] Filed: Sep. 3, 1998 coating material effective to obtain the desired post-repair
dimensions after performing a sintering heat treatment and
Related US. Application Data a hot isostatic pressing treatment, and, if performed, a
re-application of a protective coating. The coating material
[63] Continuation-in-part of application No. 08/993,116, Dec. Comprises a metal alloy capable of forming a diffusion bond
18’ 1_9_97 _ _ With the substrate of the turbine engine airfoil part. After the
[60] Provlslonal apphcanon NO‘ 60/033358’ Dec‘ 23’ 1996' coating material is applied, the sintering heat treatment
[51] Int. Cl.7 .................................................... .. B23P 15/00 process is performed to prevent gas entrapment of the
[52] US. Cl. ................. .. 29/8891; 29/40207; 29/402.18 Coating material and/or the diffusion bending area during the
[58] Field of Search ............................ .. 29/8891, 402.07, hot isostatic Pressing process‘ The?’ the hot isostatic pre_ss'
29/40218 889 40206, 228/119 mg process is performed to obtam a post-repair turbine
’ ’ ’ engine airfoil part having the desired post-repair dimensions
_ and having diffusion bonding betWeen the coating material
[56] References Clted and the turbine engine airfoil substrate. Aprotective coating
U'S' PATENT DOCUMENTS may be ?rst removed from the turbine engine airfoil part
prior to performing the high-density coating process.
4,822,248 4/1989 WentZ et al. ......................... .. 29/889.1 Typically, this protective coating is present on an airfoil part
5363554 11/1994 Partridge et a1- - 29/889-1 to protect it from the hot corrosive environment it experi
5J5Z5J429 6/1996 Mannava et a1- - 29/8891 ences during service. After performing the hot isostatic
57558922 9/1996 Gut?“ et a1‘ " 29/8891 pressing process, the protective coating may be re-applied.
5’732’467 3/1998 Whlte et a1‘ ' In this case the build-up thickness may determined to take
5,743,013 4/1998 Taylor et al. ........................ .. 29/8891 into conside’ ration the additional thickness of the post
repaired part due to the addition of the protective coating.
Primary Examiner—lrene Cuda
Attorney, Agent, or Firm—John J. Daniels 31 Claims, 12 Drawing Sheets
pSreloedcutc ta ttributes of final Step One
Determine appropriate Step Two
substrate composition
Form substrate to near Step Three
finished dimensions
Determine appropriate
coating Composition Step F our
Prepare substrate for HVOF Step Five
thermal spray coating
HVOF thermal spray coat the
substrate with the determined
coating material to form a dense Step Six
coating of the coating material on
the substrate
Determine appropriate HIP Step Seven
treatment parameters
Perform HIP treatment process on
coated substrate to obtain diffusion
bonding between the coating Step Eight
material and the substrate
If necessary, machine HIP treated
coated substrate to final Step Nine
dimensions
U.S. Patent Apr. 18,2000 Sheet 1 0f 12 6,049,978
Remove protective coating Step One-A
Determine dimensional
differences Ste’p One'B
Determine build-up
thickness Step TWO
Apply high-density
Coating Step Three
Sintering heat treatment Step Four
Hot isostatic pressing treatment Step Five
Apply protective coating Step Six
Figure 1(a)
U.S. Patent Apr. 18,2000 Sheet 2 0f 12 6,049,978
Select attributes of final
product Step One
Determine appropriate
substrate composition Step TWO
7
Form substrate to near- S
f.l n.l shed di. mensi. ons te p Three
Figure 1(b)
Determine appropriate
Coating Composition Step Four
Prepare substrate for HVOF
thermal spray coating Step Five
HVOF thermal spray coat the
substrate with the determined
coating material to form a dense Step Six
coating of the coating material on
the substrate
Determine appropriate HIP
Step Seven
treatment parameters
l
Perform HIP treatment process on
coated substrate to obtain diffusion
bonding between the coating Step Eight
material and the substrate
If necessary, machine HIP treated
Step Nine
coated substrate to final
dimensions
U.S. Patent Apr. 18,2000 Sheet 3 0f 12 6,049,978
Figure 2(a) (/f
1° . Figure 2(b)
Figure 2(d)
l |
l _ _ _ _ _ __.l
Figure 2(0)
U.S. Patent Apr. 18,2000 Sheet 4 0f 12 6,049,978
6,049,978
U.S. Patent Apr. 18,2000 Sheet 5 0f 12
Clean blade Step One
TIG weld eroded edges
with the same material Step TWO
as the blade
Grind ?ush the weld Step Three
witness lines
Mask the blade Step Four
Figure 4
V
Prepare blade for Step Five
HVOF spray
HVOF spray with the same material as the blade
the unmasked portions of the balde to build up Step Six
to a thickness greater than orginal dimensions
1
HIP treat the blade Step Seven
V
Grind and polish to Step Eight
orlginal dimenslons
U.S. Patent Apr. 18,2000 Sheet 6 0f 12 6,049,978
Figure 5(a) 18
Figure 5 (b)
20/
Figure 6(b)
Figure 6(a)
U.S. Patent Apr. 18,2000 Sheet 7 0f 12 6,049,978
22 / 22
Figure 7(b)
Figure 7(a)
Figure 8(b)
U.S. Patent Apr. 18,2000 Sheet 8 0f 12 6,049,978
/
27/
/26 Figure 9(1))
Figure 9(a)
14
Figure 10
U.S. Patent Apr. 18,2000 Sheet 9 0f 12 6,049,978
Figure 1 1(a)
2% >
Figure 1 1(b)