U.S. patent application number 10/951660 was filed with the patent office on 2005-05-12 for method of soldering a compressor nozzle ring of a gas turbine.
This patent application is currently assigned to SNECMA MOTEURS. Invention is credited to Clement, Jean-Francois.
Application Number | 20050100442 10/951660 |
Document ID | / |
Family ID | 34307526 |
Filed Date | 2005-05-12 |
United States Patent
Application |
20050100442 |
Kind Code |
A1 |
Clement, Jean-Francois |
May 12, 2005 |
Method of soldering a compressor nozzle ring of a gas turbine
Abstract
Titanium-based metal parts (1, 3) are soldered by using as a
filler metal (7) an aluminium alloy containing magnesium and
virtually no silicon. Application to the bonding of blades (3) to
the inner shroud (1) of an aeronautical gas turbine engine
compressor nozzle ring.
Inventors: |
Clement, Jean-Francois;
(Yerres, FR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SNECMA MOTEURS
Paris
FR
75015
|
Family ID: |
34307526 |
Appl. No.: |
10/951660 |
Filed: |
September 29, 2004 |
Current U.S.
Class: |
415/209.4 |
Current CPC
Class: |
F01D 9/044 20130101;
B23K 1/0018 20130101; B23K 35/0227 20130101; B23K 35/286 20130101;
B23K 2103/14 20180801; F05D 2230/237 20130101; B23K 2101/006
20180801; F05D 2300/222 20130101; B23K 1/19 20130101; F05D 2300/125
20130101 |
Class at
Publication: |
415/209.4 |
International
Class: |
F01D 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 10, 2003 |
FR |
0311890 |
Claims
1. Method of bonding titanium-based metal parts (1, 3),
characterised in that it comprises soldering under a gas pressure
of less than 1.10.sup.-2 Pa using as a filler metal an aluminium
alloy containing magnesium and virtually no silicon.
2. Method according to claim 1, wherein the aluminium alloy
contains 0.5 to 8% magnesium by mass.
3. Method according to claim 2, wherein the aluminium alloy
contains about 5% magnesium by mass.
4. Method according to one of the preceding claims, wherein the
aluminium alloy contains no more than 0.3% silicon by mass.
5. Method according to one of the preceding claims, wherein the
metal parts (1, 3) consist of a titanium-based alloy containing 5.5
to 6.75% aluminium and 3.5 to 4.5% vanadium by mass.
6. Method according to one of the preceding claims, wherein the
maximum temperature reached by the parts to be soldered (1, 3)
during soldering is between about 660 and 670.degree. C.
7. Method according to claim 6, wherein the duration of exposure of
the parts to be soldered (1, 3) to temperatures of between about
660 and 670.degree. C. is about 10 min.
8. Method according to one of the preceding claims, wherein the
filler metal penetrates into an assembly gap or clearance (9)
between the parts to be soldered (1, 3), the gap having a width of
less than 0.8 mm.
9. Method according to one of the preceding claims, wherein the
filler metal penetrates into a gap (9) between the parts to be
soldered (1, 3), the gap having a width at least equal to 0.05
mm.
10. Method according to either of claims 8 or 9, wherein the
quantity of filler metal used is between 1.5 and 2 times the volume
of the gap.
11. Method according to one of the preceding claims, wherein the
aluminium alloy is applied in the form of a wire (8).
12. Method according to claim 11, wherein the wire (8) has a
diameter of about 0.5 to 2.5 mm.
13. Method according to one of the preceding claims, wherein the
metal parts are an inner shroud (1) and a plurality of blades (3)
of a gas turbine compressor nozzle ring, the blades being
distributed in the circumferential direction and extending radially
from the inner shroud to an outer shroud (2), each blade passing
through a corresponding aperture (4) formed in the inner shroud
(1).
14. Method according to claim 13, wherein end regions (5) of the
blades (3) project radially inwards beyond the inner shroud
(1).
15. Method according to either of claims 13 or 14, in combination
with claim 11, wherein the wire (8) is placed in contact with the
inner face (6) of the inner shroud (1) and along the profile of the
blades (3).
16. Gas turbine compressor nozzle ring comprising a titanium-based
inner shroud (1), an outer shroud (2) and a plurality of
titanium-based blades (3) distributed in the circumferential
direction and extending radially from the inner shroud to the outer
shroud, each blade passing through a corresponding aperture (4)
formed in the inner shroud, characterised in that the blades are
fixed to the inner shroud by an aluminium-based solder (7)
containing magnesium and virtually no silicon, formed by the method
according to one of claims 1 to 15.
Description
[0001] The invention relates to a method of bonding titanium-based
metal parts, in particular of the inner shroud and of the blades of
a compressor nozzle ring of an aeronautical gas turbine engine.
[0002] Currently, the fixing of the titanium-alloy blades of a
nozzle ring to the titanium-alloy inner shroud is effected by
adhesion using cold-vulcanised silicone elastomers. The service
life of these elastomers decreases when the operating temperature
of the compressor increases. Thus, for new-generation compressors
operating at temperatures close to 300.degree. C. continuously in
an atmosphere containing oil fumes, the silicone elastomer-based
adhesives suffer embrittlement that limits their useful service
life to 100 hours.
[0003] Furthermore, EP 1 148 208 A discloses a method of bonding
the blades by soldering to the inner shroud of a nozzle ring, but
without indicating the constituent materials of the parts and of
the solder. The solders generally have a sufficiently long service
life in the environment mentioned above. However, the prior art
does not teach what filler metals to use which are adapted to the
soldering of titanium-based metals.
[0004] The object of the invention is to fill this gap, and thus to
eliminate the disadvantages of the known method of adhesion by
silicone elastomers.
[0005] It has been found unexpectedly that commercially available
aluminium alloys intended for machine construction or electrical
soldering are suitable for soldering titanium-based metals.
[0006] The invention aims in particular at a method of the type
defined in the introduction and provides that this comprises
soldering under a gas pressure of less than 1.10.sup.-2 Pa using as
a filler metal an aluminium alloy containing magnesium and
virtually no silicon.
[0007] The mechanical, physical and chemical properties of the bond
obtained by the method according to the invention are an
improvement on adhesive bonds. Moreover, soldering is less
expensive than adhesion both in terms of its material and its
implementation.
[0008] The presence of silicon in the filler metal is
disadvantageous as it reduces the temperature at which the solder
can be used and its resistance to corrosion.
[0009] Optional, complementary or alternative features of the
invention are given below:
[0010] The aluminium alloy contains 0.5 to 8% magnesium by
mass.
[0011] The aluminium alloy contains about 5% magnesium by mass.
[0012] The aluminium alloy contains no more than 0.3% silicon by
mass.
[0013] The metal parts are composed of a titanium-based alloy
containing 5.5 to 6.75% aluminium and 3.5 to 4.5% vanadium by
mass.
[0014] The maximum temperature reached by the parts to be soldered
during soldering is between about 660 and 670.degree. C.
[0015] The duration of exposure of the parts to be soldered to
temperatures of between about 660 and 670.degree. C. is about 10
minutes.
[0016] The filler metal penetrates into an assembly gap or
clearance between the parts to be soldered of a width of less than
0.8 mm.
[0017] The filler metal penetrates into a gap between the parts to
be soldered of a width of at least 0.05 mm.
[0018] A quantity of filler metal is used which is between 1.5 and
2 times the volume of the said gap.
[0019] The aluminium alloy is applied in the form of a wire.
[0020] The wire has a diameter of about 0.5 to 2.5 mm.
[0021] The metal parts are an inner shroud and a plurality of gas
turbine compressor nozzle ring blades, the blades being distributed
in the circumferential direction and extending radially from the
inner shroud to an outer shroud, each one passing through a
corresponding aperture formed in the inner shroud.
[0022] End regions of the blades project radially inwards beyond
the inner shroud.
[0023] The wire is placed in contact with the inner face of the
inner shroud and along the profile of the blades.
[0024] The invention also relates to a gas turbine compressor
nozzle ring comprising a titanium-based inner shroud, an outer
shroud and a plurality of titanium-based blades distributed in the
circumferential direction and extending radially from the inner
shroud to the outer shroud, each blade passing through a
corresponding aperture formed in the inner shroud, characterised in
that the blades are fixed to the inner shroud by an aluminium-based
solder containing magnesium and virtually no silicon, formed in
particular by the method above.
[0025] The features and advantages of the invention are explained
in more detail in the description below with reference to the
attached drawings.
[0026] FIG. 1 is a partial view in axial section of a stage of an
aeronautical gas turbine engine compressor nozzle ring, showing one
blade connected to the inner shroud by the method according to the
invention.
[0027] FIG. 2 is a detail in section showing an aluminium alloy
wire positioned with a view to soldering the blade to the inner
shroud.
[0028] FIG. 3 is a view similar to FIG. 2 showing the assembly
obtained after soldering.
[0029] In FIGS. 2 and 3, for greater clarity, the shroud 1 and the
blade 3 are shown diagrammatically in the form of plane plates of
uniform thickness.
[0030] The nozzle ring stage partially shown comprises,
conventionally, an inner shroud 1 and an outer shroud 2, both
fixed, and a series of rectifying blades 3 extending in a generally
radial direction from the inner shroud to the outer shroud. The
blades 3 are distributed in the circumferential direction,
generally in a uniform manner. The inner shroud 1 is pierced with
apertures 4 whose shape is adapted to the profile of the blades.
Each aperture is traversed by a blade 3, one end region 5 of which
projects in the axial direction of the engine beyond the aperture 4
and consequently beyond the inner face 6 of the shroud 1. The
blades 3 are fixed to the outer shroud 2 e.g. by electron-beam
soldering.
[0031] According to the invention, the blades 3 are fixed to the
inner shroud 1 by solders 7 formed by using as a filler metal an
aluminium alloy containing 0.5 to 8% magnesium by mass and
virtually no silicon.
[0032] Advantageously, the aluminium alloy is realised as a wire of
a diameter of about 2 mm.
[0033] An embodiment of the invention is given below by way of
example for the soldering of blades to an inner shroud of a stage
of an aeronautical gas turbine engine compressor nozzle ring, the
blades and the inner shroud being made of the alloy TA6V, which is
a titanium-based alloy containing 6% aluminium and 4% vanadium by
mass.
[0034] The blades 3 are inserted into the apertures 4 formed in the
wall of the inner shroud 1 and adapted to the transverse
cross-section of the blades, in such a manner that an assembly gap
or clearance 9 of a width of 0.35 mm is left around the blades
between their surface and the opposite surface of the apertures 4.
An end region 5 of each blade projects in the axial direction of
the engine beyond the inner face 6 of the shroud 1. A wire 8 made
of an aluminium-based alloy containing 5% magnesium and less than
0.3% silicon by mass and having a diameter of 2 mm is placed folded
into a U around the region 5, so as to come into contact with the
opposite faces thereof and with the face 6 of the shroud, as is
shown in FIG. 2.
[0035] The assembly thus obtained is placed in a vacuum furnace
wherein the pressure is reduced to below 1.10.sup.-2 Pa. Then the
following heating cycle is applied:
[0036] increase from 20 to 400.degree. C. at 7.degree. C./min
[0037] maintain at 400.degree. C. for 30 min
[0038] increase to 600.degree. C. at 7.degree. C./min
[0039] maintain at 600.degree. C. for 10 min
[0040] increase to 660.degree. C. at 7.degree. C./min
[0041] maintain between 660 and 670.degree. C. for 10 minutes
[0042] cool under a vacuum to 400.degree. C., then under a neutral
gas.
[0043] During this treatment, the metal forming the wire 8 melts
and penetrates by capillary action into the assembly gap or
clearance 9, which it fills to form upon cooling a solder 7, which
forms joining radii 10 on each side of the shroud and the
blade.
[0044] The example given above is non-limiting. In particular, the
filler metal can be realised in a form other than a wire, e.g. in
the form of a strip, powder or paste, and can then be placed in the
gap 9, preferably overflowing on the inside and/or outside of the
shroud 1. The titanium-based metal forming the parts to be soldered
may have a different composition from that of the alloy TA6V.
* * * * *