U.S. patent application number 11/184927 was filed with the patent office on 2006-02-02 for shot, devices, and installations for ultrasonic peening, and parts treated thereby.
This patent application is currently assigned to SONATS-SOCIETE DES NOUVELLES APPLICATIONS DES TECHNIQUES DE SURFACES. Invention is credited to Patrick Cheppe, Vincent Desfontaine, Jean-Michel Duchazeaubeneix.
Application Number | 20060021410 11/184927 |
Document ID | / |
Family ID | 35730639 |
Filed Date | 2006-02-02 |
United States Patent
Application |
20060021410 |
Kind Code |
A1 |
Cheppe; Patrick ; et
al. |
February 2, 2006 |
Shot, devices, and installations for ultrasonic peening, and parts
treated thereby
Abstract
Shot for use in a peening installation, the shot having:
hardness greater than or equal to 800 HV; density greater than or
equal to 8 g/cm.sup.3; and pieces having a maximum dimension less
than or equal to 1.5 mm.
Inventors: |
Cheppe; Patrick;
(Basse-Goulaine, FR) ; Desfontaine; Vincent;
(Sainte Lumine de Coutais, FR) ; Duchazeaubeneix;
Jean-Michel; (Les Sorinieres, FR) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
SONATS-SOCIETE DES NOUVELLES
APPLICATIONS DES TECHNIQUES DE SURFACES
Reze
FR
|
Family ID: |
35730639 |
Appl. No.: |
11/184927 |
Filed: |
July 20, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60599364 |
Aug 6, 2004 |
|
|
|
Current U.S.
Class: |
72/53 |
Current CPC
Class: |
Y10S 72/707 20130101;
C21D 10/00 20130101; C21D 7/06 20130101; Y10T 29/479 20150115; B24C
5/005 20130101 |
Class at
Publication: |
072/053 |
International
Class: |
B21D 31/06 20060101
B21D031/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 30, 2004 |
FR |
04 08493 |
Claims
1. Shot for use in a peening installation, the shot having:
hardness of at least 800 HV; density of at least 8 g/cm.sup.3; and
pieces having a maximum dimension not greater than 1.5 mm.
2. Shot according to claim 1, wherein the installation is an
ultrasonic peening installation.
3. Shot according to clam 1, wherein the hardness is at least 1300
HV.
4. Shot according to claim 1, wherein each piece is substantially
spherical.
5. Shot according to claim 1, wherein the shot is spherical with a
maximum tolerance of .+-.60 .mu.m.
6. Shot according to claim 1, wherein the density is at least to 12
g/cm.sup.3.
7. Shot according to claim 1, wherein a surface of the shot
comprises at least one non-ferrous material.
8. Shot according to claim 7, wherein the surface comprises at
least tungsten carbide.
9. Shot according to claim 8, the shot being made entirely of
tungsten carbide.
10. Shot for use in an ultrasonic peening installation including at
least one sonotrode, the shot comprising at least one non-ferrous
material at a surface thereof, and including a density of at least
3 g/cm.sup.3.
11. Shot according to claim 10, wherein the non-ferrous material is
tungsten carbide.
12. Shot according to claim 10, wherein the density is at least 12
g/cm.sup.3.
13. Shot for use in a peening installation including at least one
sonotrode, each piece of shot comprising a core made of at least
one first material, and at least one second material different from
the first material in a shell surrounding the core.
14. Shot according to claim 13, wherein the second material has a
hardness greater than that of the first material.
15. Shot according to claim 14, wherein the second material is a
non-ferrous material.
16. Shot according to claim 15, wherein the second material has a
hardness of at least 800 HV.
17. Shot according to claim 16, wherein the hardness of the second
material is at least 1300 HV.
18. Shot according to claim 1, wherein the second material
comprises tungsten carbide.
19. A peening device comprising at least one sonotrode for setting
at least one piece of shot into motion, said sonotrode including at
least one surface for coming into contact with the shot, wherein
the sonotrode comprises a metal body coated with a surface deposit
of a material that is harder than a base metal and has a thickness
of at least 0.5 mm.
20. A device according to claim 19, wherein the metal body
comprises titanium.
21. A device according to claim 19, wherein the thickness of the
deposit is at least 0.75 mm.
22. A device according to claim 21, wherein the thickness is at
least 0.9 mm.
23. A device according to claim 19, wherein the deposit is based on
tungsten carbide.
24. A device according to claim 19, wherein the sonotrode comprises
a body that is made at least in part of titanium.
25. A peening device comprising at least one sonotrode for setting
at least one piece of shot into motion, the sonotrode comprising a
body made at least in part of titanium, at least part of which is
forged titanium.
26. A device for treating at least one part by peening, the device
comprising at least one sonotrode and a treatment chamber in which
shot can be set into motion by the sonotrode, the device including
at least one of an elastically-deformable wall and an
elastically-deformable projection for coming to bear against the
part for treatment.
27. A device according to claim 26, including a filler element of
shape that substantially matches a shape of a face of the part for
treatment that is situated facing away from the sonotrode.
28. An installation for peening a part for treatment, the
installation comprising: at least one sonotrode; and at least one
piece of shot including a surface of non-ferrous material, an
amplitude of vibration of the sonotrode being selected in such a
manner as to induce stresses in the part for treatment
corresponding to an ALMEN intensity of at least F8A.
29. A device for peening at least one part for treatment, the
device comprising a sonotrode for projecting shot against the part
for treatment, the sonotrode including at least one cavity into
which the part for treatment is partially engaged.
30. A device according to claim 29, wherein the cavity is formed as
a hollow in a substantially planar end face of the sonotrode.
31. A peening installation comprising at least one sonotrode and at
least one piece of shot as defined in claim 1.
32. An installation according to claim 31, wherein the sonotrode is
excited at a frequency lying in a range of about 10 kHz to about 60
kHz.
33. A method of treating at least one root of a blade including a
longitudinal axis in a peening installation, said peening
installation comprising shot and a peening device comprising a
sonotrode including a longitudinal axis, wherein the root of the
blade is placed in such a manner that the longitudinal axis of the
blade is substantially perpendicular to the longitudinal axis of
the sonotrode.
34. A method according to claim 33, wherein at least one of an
elastically-deformable wall and an elastically-deformable
projection is placed on an end face of the blade root that faces
substantially away from the blade.
35. A method according to claim 33, wherein a space situated behind
the face of the blade root facing away from the sonotrode is filled
with a filler element of shape that substantially matches a shape
of said face.
36. A part treated in a peening installation using at least one
piece of shot as defined in claim 1, the part including a peened
surface with no ferrous deposit and no ferrous encrustation and
including at least one concave portion with a radius of curvature
not greater than 1.5 mm.
37. A part according to claim 36, wherein the surface exposed to
peening includes, after treatment, a stress level corresponding to
an ALMEN intensity greater than F8A.
Description
[0001] This non provisional application claims the benefit of
French Application No. 04 08493 filed on Jul. 30, 2004 and U.S.
Provisional Application No. 60/599,364 filed on Aug. 6, 2004.
[0002] The present invention relates to shot, devices, and
installations for ultrasonic peening, and also to parts thus
treated by peening.
BACKGROUND
[0003] Methods and installations for ultrasonic peening are
described in particular in French patents FR 2 815 280 and FR 2 815
281, using at least one sonotrode comprising a titanium body for
putting shot into motion for inducing compression stresses in the
treated part.
[0004] The following publications also relate to ultrasonic
peening: U.S. Pat. No. 6,490,899 B2, U.S. Pat. No. 6,343,495 B1,
U.S. Pat. No. 6,467,321 B2, U.S. Pat. No. 6,336,844 B1, U.S. Pat.
No. 6,289,705 B1, U.S. Pat. No. 6,508,093 B2, US 2003/0115922 A1,
U.S. Pat. No. 6,505,489 B2, and U.S. Pat. No. 6,536,109 B2.
[0005] The shot used and described in the past in those patents
mainly comprises steel balls having a diameter of about 2
millimeters (mm) for example. The use of such shot does not enable
treatment to be sufficiently intense on concave surfaces that
present a radius of curvature smaller than that of the balls, or in
the bottoms of certain setbacks.
SUMMARY
[0006] In a first of its aspects, the present invention seeks to
remedy that drawback, and it achieves this by means of shot for use
in a peening installation, in particular an ultrasonic peening
installation in which the shot is propelled by at least one
sonotrode, the shot being characterizable by the fact that it
presents:
[0007] hardness greater than or equal to a Vickers hardness number
800 HV, preferably greater than or equal to 1300 HV;
[0008] density greater than or equal to 8 grams per cubic
centimeter (g/cm.sup.3), better greater than or equal to 12
g/cm.sup.3; and
[0009] pieces having a maximum dimension less than or equal to 1.5
mm.
[0010] The use of such shot makes it possible to treat zones that
are difficult to access using conventional pieces having small
radii of curvature, and in particular less than 1.5 mm, the shot
nevertheless being capable of acquiring sufficient kinetic energy
to generate the desired level of stress in the part and remaining
compatible with the use of a sonotrode.
[0011] The pieces of shot are preferably substantially spherical,
in particular with maximum tolerance of .+-.60 micrometers (.mu.m)
on sphericity.
[0012] The shot preferably comprises at least one non-ferrous
material at its surface, advantageously tungsten carbide (WC). The
shot may be made entirely out of tungsten carbide.
[0013] Furthermore, the presence of iron in conventional steel shot
for prior art peening installations leads to a ferrous deposit
being formed on the treated part and/or to encrustations that must
subsequently be eliminated, since otherwise they will oxidize, and
that requires parts to be cleaned after they have been peened. The
cleaning operation is also known as decontamination and it is
performed in baths. For example, chemical etching baths are used,
but they also lower the level of residual stresses and reduce the
fatigue strength of the part.
[0014] In another of its aspects, the invention seeks to avoid that
additional treatment, thereby maintaining the fatigue strength of
the treated part.
[0015] The invention achieves this by means of shot for use in a
peening installation, in particular a peening installation in which
the shot is set into motion by at least one sonotrode, the shot
comprising at least one non-ferrous material at its surface, and
presenting density greater than or equal to 3 g/cm.sup.3, better
greater than or equal to 12 g/cm.sup.3.
[0016] The non-ferrous material is advantageously tungsten carbide
(WC).
[0017] In another of its aspects, independently or in combination
with the above, the invention provides shot for use in a peening
installation, in particular an installation for ultrasonic peening
and including at least one sonotrode, each piece of shot
comprising:
[0018] a core made of at least one first material; and
[0019] at least one second material different from the first in a
shell surrounding the core.
[0020] Such composite pieces of shot can make it possible, for
example, to make the core out of a material that is less expensive
than the material used for making the shell, thereby contributing
to reducing costs. This can also make it possible for the core to
be made of a material of greater density, but presenting
insufficient hardness.
[0021] Preferably, the second material presents hardness greater
than that of the first, in particular hardness greater than or
equal to 800 HV, better greater than or equal to 1300 HV, and also
preferably the second material is a non-ferrous material, e.g.
tungsten carbide (WC).
[0022] In another of its aspects, individually or in combination
with the above, the invention also provides a peening device having
at least one sonotrode for setting at least one piece of shot into
motion, in particular shot as defined above, said sonotrode
presenting at least one face for coming into contact with the shot,
the device being characterizable by the fact that the sonotrode has
a metal body, preferably made of titanium, coated in a deposit of a
material that is not as hard as the base metal, to a thickness
greater than or equal to 0.5 mm, and advantageously based on
tungsten carbide.
[0023] Such a device makes it possible to obtain a sonotrode having
much greater resistance to wear (abrasion), in particular when
using shot presenting the above-defined characteristics, but
without harming the acoustic operation of the sonotrode.
[0024] The thickness is preferably greater than or equal to 0.75
mm, e.g. lying in the range 0.9 mm to 1.1 mm.
[0025] In another of its aspects, independently or in combination
with the above, the invention also provides a device for treating
at least one part by peening, the device comprising at least one
sonotrode for setting at least one piece of shot into motion, e.g.
shot as defined above, said sonotrode comprising a body made at
least in part out of titanium, the device being characterizable by
the fact that the body is made at least in part and preferably
entirely out of forged titanium.
[0026] The Applicant has found that forged titanium can be used for
fabricating a sonotrode, thus making it possible for example to
diversify sources of supply in the event of there being a shortage
of titanium obtained by rolling, as has been used until now for
fabricating sonotrodes.
[0027] In this particular aspect, the invention is not limited to
sonotrodes used for ultrasonic peening, and it can be applied to
sonotrodes used for ultrasonic welding. The invention thus also
provides a sonotrode considered in isolation and made at least in
part out of forged titanium.
[0028] In another of its aspects, independently or in combination
with the above, the invention also provides a device for treating
at least one part by peening, the device comprising at least one
sonotrode and a treatment chamber in which shot is set into motion
by the sonotrode, wherein the chamber includes at least one wall or
projection for coming to bear against the part for treatment.
[0029] Such a device may present the advantage of enabling pieces
of shot of relatively small size to be used, without any fear of
them becoming engaged in an opening in the treated part, for
example, with such an opening being closed by the wall or
projection, and with the advantage of defining treatment zones,
thereby avoiding the need for masking and demasking operations.
[0030] In another of its aspects, independently or in combination
with the above, the invention also provides a device for treating
at least one part by peening, the device comprising at least one
sonotrode and a treatment chamber in which shot can be set into
motion by the sonotrode, the device including a filler element of
shape that matches substantially the shape of a face of the part
for treatment that faces away from the sonotrode.
[0031] Such a filler element can serve to accelerate the return of
shot to the sonotrode or to avoid some shot failing to return to
the sonotrode.
[0032] In another of its aspects, independently or in combination
with the above, the invention also provides an installation for
peening a part for treatment, the installation comprising:
[0033] at least one sonotrode; and
[0034] at least one piece of shot presenting a surface made of
non-ferrous material, the amplitude of vibration of the sonotrode
being selected in such a manner as to induce in the part for
treatment stresses that correspond to an ALMEN intensity of at
least F8A.
[0035] In another of its aspects, independently or in combination
with the above, the invention also provides a device for peening at
least one part for treatment, the device comprising a sonotrode for
propelling shot against the part for treatment, said sonotrode
having at least one cavity in which a portion of the part for
treatment is engaged. The part for treatment is thus not engaged
inside said cavity.
[0036] By way of example, the cavity is made in a substantially
plane end face of the sonotrode.
[0037] Such a device makes it easier and quicker to treat parts
that have projecting portions, which portions can be engaged in
part in the sonotrode cavity, thereby reducing treatment time.
[0038] The path between the vibrating surface of the sonotrode and
the treated part can be shortened and, for example, the cavity can
be made to have inclined faces contributing to directing the shot
towards certain zones of the part for treatment, which zones would
otherwise be more difficult to reach, and/or contributing to
reducing the angle of incidence of the shot, thereby increasing its
impact force and reducing treatment time.
[0039] The invention also provides a peening installation
comprising a sonotrode and at least one piece of shot as defined
above. In such an installation, the sonotrode is excited, for
example, at a frequency lying in the range 10 kilohertz (kHz) to 60
kHz, e.g. a frequency of about 15 kHz, 20 kHz, or 40 kHz.
[0040] Furthermore, U.S. Pat. No. 6,536,109 teaches treating a
plurality of blade roots by peening, with the roots being placed in
an enclosure, and the longitudinal axes of the blades being
directed parallel to the longitudinal axis of the sonotrode.
[0041] In another of its aspects, the invention seeks to further
improve the treatment of blade roots.
[0042] The invention achieves this by means of a method of treating
at least one blade root in a peening installation, the blade having
a longitudinal axis, the peening installation comprising a peening
device comprising a sonotrode with a longitudinal axis and shot set
into motion by the sonotrode, the method being characterizable by
the fact that the root is placed in such a manner that the
longitudinal axis of the blade is substantially perpendicular to
the longitudinal axis of the sonotrode.
[0043] An elastically-deformable endpiece may be placed against an
end face of the blade root, situated substantially opposite from
the blade.
[0044] Advantageously, the space situated behind the side face of
the root that is facing away from the sonotrode is filled with a
filler element of a shape that substantially matches the shape of
said face.
[0045] In another of its aspects, independently or in combination
with the above, the invention also provides a part treated in a
peening installation using at least one piece of shot as defined
above, the part presenting a peened surface free from any ferrous
deposit or encrustation and having at least one concave portion
with a radius of curvature less than or equal to 1.5 mm, in
particular less than or equal to 0.7 mm. The peened surface
preferably presents a stress level having an ALMEN intensity
greater than or equal to F8A.
[0046] In another of its aspects, independently or in combination
with the above, the invention also provides a device for peening a
part having cells that open out radially in its periphery, the
device comprising a treatment chamber that is open to the
sonotrode, said treatment chamber allowing a peripheral region of
the part that includes the cells to pass therethrough, the part
being driven to rotate relative to the sonotrode about an axis
substantially parallel to the longitudinal axis of the
sonotrode.
[0047] In another of its aspects, independently or in combination
with the above, the invention also provides a device for peening a
part having a peripheral annular groove, in particular a groove
presenting a cross-section with a constriction, the device
comprising a treatment chamber having side walls disposed on either
side of the part, in particular side walls covering the side faces
of the part, an end wall uniting the side walls, said end wall
being pierced by an opening that opens out to the sonotrode so as
to enable shot to impact the sonotrode and be set into motion
thereby inside the treatment chamber, the treatment chamber being
disposed in such a manner as to be capable of allowing the part to
pass therethrough, the part being driven to rotate about an axis
substantially perpendicular to the longitudinal axis of the
sonotrode.
[0048] In another of its aspects, independently or in combination
with the above, the invention also provides a peening device
comprising a treatment chamber open to a sonotrode and a deflector
for deflecting shot present in the treatment chamber and set into
motion by the sonotrode so that they are directed towards the
surface for treatment.
[0049] By way of example, the deflector may be conical in shape so
as to enable a tubular wall to be treated, e.g. a through hole. By
way of example, the treatment chamber may be defined between a top
portion comprising the deflector and a bottom portion comprising
the sonotrode.
[0050] In another of its aspects, independently or in combination
with the above, the invention also provides a device for peening a
cylindrical part provided at one end with a set of teeth, the
device comprising a sonotrode and a treatment chamber through which
the teeth pass, the part being driven to rotate about an axis
perpendicular to the longitudinal axis of the sonotrode, the
treatment chamber including a deflector for deflecting the shot
towards the bottoms of the grooves formed between the teeth in the
set.
[0051] In a variant, the part is driven to rotate about an axis
that is substantially parallel to the longitudinal axis of the
sonotrode, and the treatment chamber includes sloping walls for
deflecting the shot towards the radially-inner and radially-outer
faces of the teeth in the set.
[0052] In another variant, the set of teeth is fully engaged in the
treatment chamber, which chamber may include a central conical
deflector enabling shot to be deflected towards the radially-inner
surfaces of the teeth in the set, and a peripheral deflector
enabling the shot to be deflected towards the radially-outer
surfaces of the teeth in the set. The part may be optionally driven
relative to the sonotrode about an axis that is substantially
parallel to the longitudinal axis of the sonotrode.
[0053] In another of its aspects, independently or in combination
with the above, the invention also provides a device for peening a
part including a tapped hole, the device comprising a sonotrode and
a treatment chamber defined at least in part by a deflector that is
inserted inside the tapped hole, said deflector including a wall
that is inclined relative to the longitudinal axis of the sonotrode
so as to deflect shot towards a thread of the tapped hole. The axis
of the sonotrode may be substantially parallel to the axis of the
tapped hole. Means may be provided for causing the deflector to
move relative to the part for treatment. The part for treatment may
be driven in rotation about the longitudinal axis of the sonotrode,
for example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] The invention can be better understood on reading the
following detailed description of non-limiting embodiments thereof,
and on examining the accompanying drawings, in which:
[0055] FIG. 1 is a diagrammatic view of an example of a piece of
shot in one aspect of the invention;
[0056] FIG. 2 is a fragmentary and diagrammatic section view of a
part having a concave portion presenting a small radius of
curvature;
[0057] FIG. 3 is a cross-section in a midplane of a piece of
composite shot in accordance with another aspect of the
invention;
[0058] FIG. 4 is a diagrammatic and fragmentary view of a peening
installation in another aspect of the invention;
[0059] FIG. 5 shows a detail V of FIG. 4;
[0060] FIG. 6 is a diagrammatic and fragmentary axial section view
of a sonotrode made in accordance with another aspect of the
invention;
[0061] FIGS. 7 and 8 are diagrammatic and fragmentary views of an
installation for peening blade roots in accordance with another
aspect of the invention;
[0062] FIG. 9 is a diagrammatic and fragmentary view of an example
of a part for treatment;
[0063] FIG. 10 is a diagrammatic view of a peening installation
suitable for use in treating the FIG. 9 part;
[0064] FIGS. 11 to 13 show other examples of a peening
installation;
[0065] FIG. 14 is a diagrammatic and fragmentary view of another
example of a part for treatment;
[0066] FIGS. 15 to 17 show examples of peening installations
suitable for use in treating the FIG. 15 part; and
[0067] FIGS. 18 and 19 show other examples of peening
installations.
MORE DETAILED DESCRIPTION
Shot
[0068] In one of its aspects, the invention relates to shot for use
in a peening installation comprising a sonotrode that is set into
vibration at ultrasound frequencies by a suitable generator. The
shot may be characterized by hardness greater than or equal to 800
HV, density greater than or equal to 8 g/cm.sup.3, and pieces
having a maximum dimension that is less than or equal to 1.5
mm.
[0069] FIG. 1 shows a piece of shot 1 satisfying this definition,
and that is substantially spherical shape, with the above-mentioned
maximum dimension corresponding to the diameter d of the sphere.
Preferably, the tolerance on its sphericity is better than .+-.60
.mu.m.
[0070] Its hardness is preferably greater than or equal to 1300 HV,
and its density is preferably greater than or equal to 12
g/cm.sup.3.
[0071] By way of example, the shot 1 is made entirely out of
tungsten carbide or any other material presenting the required
hardness and density. The tungsten carbide includes a binder of
cobalt or nickel, for example.
[0072] The material used is preferably non-ferrous, thereby
presenting the advantages explained above.
[0073] In an embodiment of the invention, the piece of shot 1 is a
ball of diameter d equal to 0.91 mm, and made of tungsten carbide
(WC). By way of example, such a piece of shot is used in an
ultrasonic peening installation and is propelled by the vibrating
surface of a sonotrode in which the amplitude of vibration lies,
for example, in the range 60 .mu.m to 80 .mu.m, approximately, so
that the kinetic energy of the shot impacting against the part for
treatment can generate stresses presenting an ALMEN intensity of
least F8A once the part has been treated.
[0074] By way of example, the excitation frequency of the sonotrode
lies in the range 10 kHz to 60 kHz, e.g. 20 kHz. The frequency may
be selected as a function of the characteristics of the zone to be
treated and of the characteristics of the required treatment, for
example.
[0075] The small size of the piece of shot 12 makes it possible to
treat concave surfaces having a radius of curvature r that is
relatively small, as shown in FIG. 2, e.g. a radius of curvature r
less than or equal to 0.7 mm.
[0076] In another aspect of the invention, the shot 1 may be
composite, as shown in FIG. 3, e.g. each piece comprising a core 2
of a first material and a shell 3 of a second material, preferably
harder than the first and non-ferrous, the hardness of the second
material being greater than or equal to 800 HV, and better greater
than or equal to 1300 HV, for example, and said second material
preferably being tungsten carbide.
[0077] By way of example, the core may be made of steel, of
uranium, or of any other material that is compatible with having
the second material deposited thereon and with obtaining the
compression stresses that are generated by peening.
Sonotrodes
[0078] In accordance with another aspect of the invention, as shown
in FIGS. 4 and 5, the sonotrode 11 used for setting the shot 1 into
motion, in particular the above-mentioned tungsten carbide shot,
may comprise a body 4 made of titanium, coated on its side that is
to be impacted by the shot in a deposit 5 of material that is
harder than titanium, to a thickness e that is greater than or
equal to 0.5 mm. The outside surface of the deposit is preferably
prepared (rectified or machined) so as to return the sonotrode to
its initial shape. By way of example, the material constituting the
deposit 5 is tungsten carbide deposited on the titanium by any
suitable method, in particular by a method implemented by the
French supplier TECHNOGENIA (Saint Joriez). The thickness e may be
greater than or equal to 0.75 mm, for example, and better greater
than or equal to 0.9 mm, e.g. being about 1 mm.
[0079] In another aspect of the invention, the body 4 of the
sonotrode can be made, independently of the optional presence of
the deposit 5, at least in part out of forged titanium, e.g.
titanium Ti 10.2.3. Forged titanium withstands the internal
stresses induced by the ultrasonic vibration while the sonotrode is
in operation.
[0080] In another aspect of the invention, shown in FIG. 6, the
vibrating face 7 of the sonotrode 11 that is impacted by the shot
may present at least one cavity 8 in which the part 93 to be
treated is partially engaged. The vibrating face 7, with the
exception of the cavity 8, is plane, for example, extending
substantially perpendicularly to the longitudinal axis X of the
sonotrode 11.
[0081] By way of example, the portion of the part 9 that is engaged
in the cavity 8 may be a blade root or platform, or a shoulder on a
shaft.
[0082] By way of example, the cavity 8 is defined by sloping walls
90 and 91 which may form a V-shape when the portion of the part 9
being treated is substantially rectilinear, for example.
[0083] The inclination of the walls 90 and 91 enables the shot to
reach the opposite faces of the portion of the part 9 that is
engaged in the cavity 9 at a smaller angle of incidence.
Peening Installations
[0084] The peening installations to which the invention applies
comprise at least one sonotrode and at least one piece of shot set
into motion by the sonotrode so as to impact against the part for
treatment, either directly or after being reflected on at least one
deflector, which may be constituted by a wall of the treatment
chamber, for example.
[0085] By way of example, the shot may be one of the varieties
defined above, in particular being made out of tungsten carbide, or
out of steel, or having a composite structure.
[0086] The amplitude of vibration of the sonotrode is selected so
as to induce stresses in the part for treatment that corresponds to
an ALMEN intensity greater than or equal to F8A, for example. This
amplitude preferably lies in the range 1 .mu.m to 300 .mu.m.
[0087] Depending on the nature and in particular on the shape of
the part for treatment, the peening installation may present a
variety of configurations.
[0088] When the part for treatment is a blade, for example, having
a longitudinal axis Y as shown in FIGS. 7 and 8, and including a
root 10 for enabling it to be fastened to a support of annular
shape, then the blade 9 is preferably oriented with its
longitudinal axis Y substantially perpendicular to the longitudinal
axis X of the sonotrode 11, thus making it easier to treat the side
faces 17 and 18 of the root 10.
[0089] For such a part, the shot that is used is preferably made up
of small tungsten carbide balls of diameter less than or equal to
1.2 mm, e.g. about 0.91 mm.
[0090] In this example, the installation 12 advantageously includes
a removable portion 13a supporting a filler element 14 presenting a
portion 15 of shape matching the shape of the side face 17 that
faces away from the sonotrode, a movable portion 13b and a
stationary portion 13c placed above the sonotrode 11 at a distance
that is less than the diameter of a piece of shot, and preferably
substantially equal to one-third the shot diameter.
[0091] The function of the stationary portion 13c is to keep shot
at rest on the sonotrode so as to leave the portions 13a and 13b
free for handling without running any risk of dispersing shot
outside the treatment chamber 30.
[0092] Where appropriate, the removable portion 13a may have a
second filler element 19 presenting a portion 20 of shape that
matches that of the other side face 18 so as to enable the side
face 17 to be treated after the removable portion 13b has been
turned over.
[0093] This portion is held in place in a housing 22 defined in the
example being described between two portions 24 and 25 that are
capable of being displaced relative to each other, e.g. by being
pivoted, as shown. The inside face of each of the portions 24 and
25 that comes into contact with the blade 9 may be defined by a
removable portion 26 of shape that matches that of the blade 9,
thus enabling the installation to be adapted to other parts for
treatment merely by changing the removable portion 26.
[0094] The portions 24 and 25 may also include gaskets 27 of
elastically-deformable material, these gaskets 27 serving to close
the treatment chamber 30 in shot-tight manner.
[0095] In particular when the root 10 includes at least one opening
in its end face 33 remote from the blade 9, an endpiece 31 of
elastically-deformable material may be pressed against said end
face 33, specifically for preventing shot from penetrating into the
above-mentioned opening(s). The endpiece 31 may be secured to the
end of a support 32, e.g. made of a synthetic material that
withstands impacts from the shot throughout the duration of
treatment to the root 10.
[0096] Naturally, the invention may be applied to a wide variety of
parts.
[0097] In the example shown in FIGS. 9 and 10, the part 41 for
treatment presents cells 40 that are distributed around its
circumference.
[0098] This part 41 can be driven in rotation about an axis of
rotation parallel to the longitudinal axis of the sonotrode 11, the
cells 40 passing through a treatment chamber 42 having its bottom
closed by the sonotrode 11 and its top closed by a wall 43 that is
suitable for being replaced by the sonotrode 11 so as to enable the
opposite face to be treated simultaneously.
[0099] For a part presenting an annular groove 44 in its periphery,
as shown in FIG. 11, the installation may comprise, for example,
side walls 44 that cover the sides of the parts to be treated and
an end wall 47 for interconnecting the side walls 45 and closing
the treatment chamber 44, said wall 47 being pierced by an opening
46 enabling the shot 1 set into motion by the sonotrode 11 to
impact against the part that is to be treated.
[0100] By way of example, this part may be driven to rotate about
an axis W placed perpendicular to the longitudinal axis X of the
sonotrode.
[0101] In order to treat the inside edge 49 of a hole 50 in a part
51, as shown in FIG. 12, it is possible for example to provide a
treatment chamber 50 that is closed at its top end and that opens
out at its bottom end to the vibrating face of the sonotrode
11.
[0102] Where appropriate, and as shown in FIG. 13, it is possible
to make the treatment chamber with at least one central deflector
52, e.g. of conical shape, so that by bouncing against the
deflector, the shot can reach the edge 49 at a smaller angle of
incidence.
[0103] In order to treat a part 60 that is, for example,
cylindrical in shape with one end carrying a set of teeth 61, also
known as a dog or curvic coupling, as shown in FIG. 14, it is
possible to use one of the installations shown in FIGS. 15 to 17,
for example.
[0104] In the configuration of FIG. 15, the part 60 is driven to
rotate about an axis K that is perpendicular to the longitudinal
axis X of the sonotrode 4, and the peening treatment of the set of
teeth 61 is performed by causing said set of teeth to pass through
a treatment enclosure 63 having an obliquely sloping wall 64 for
deflecting shot coming from the vibratory surface of the sonotrode
11 into the bottoms of the grooves formed between the teeth, the
wall 64 sloping at an angle of substantially 45.degree., for
example, relative to the longitudinal axis X of the sonotrode
11.
[0105] In the configuration of FIG. 16, the part 60 is driven in
rotation about an axis T that is parallel to the axis X of the
sonotrode 11, the bottoms of the grooves formed between the teeth
in the set 61 facing the vibrating surface of the sonotrode 11.
[0106] The treatment chamber may include walls 66 that slope
obliquely relative to the longitudinal axis X of the sonotrode so
as to deflect the shot towards the radially-outer and
radially-inner faces 68 and 69 respectively of the teeth in the set
61.
[0107] In the configuration of FIG. 17, the sonotrode 11 is large
enough to treat all of the teeth in the set 61 simultaneously, the
treatment chamber presenting, for example, a conical deflector 62
in its center enabling the shot to be deflected towards the
radially-inner face 69 of the part 60.
[0108] The treatment chamber may also present a peripheral wall 70
of conical shape, enabling the shot to be deflected towards the
radially-outer face 68 of the part 60. The part may optionally be
driven in rotation about an axis coinciding with the longitudinal
axis X of the sonotrode.
[0109] FIG. 18 shows the possibility of treating a hole 73 together
with the two inlet faces 74 and 75 of the part 72.
[0110] FIG. 19 shows the possibility of peening a tapped hole 78 by
inserting therein a deflector 79 defining at least part of a
treatment chamber, presenting a wall 80 that slopes relative to the
longitudinal axis X of the sonotrode 11, thereby enabling shot to
be directed towards the threads 81 of the tapped hole 78.
[0111] In all of the above examples, a plurality of sonotrodes can
be used simultaneously for treating a single part.
[0112] These various configurations can be applied statically.
However, when the part is driven in rotation, it can be driven
continuously, or intermittently.
[0113] Where appropriate, it is possible to use a mixture of shot
of different natures and/or different dimensions.
[0114] The invention is not limited to the examples described
above, and can be applied to any part used in aviation or in the
automobile industry, in particular for blades, vanes, turbines,
threads, slots for receiving blade roots, fastener members of all
kinds, welding beads, coupling radii between a blade and a flow
path, inter-disk pockets, etc.
[0115] Throughout the description, including in the claims, the
term "comprising a" should be understood as being synonymous with
"comprising at least one", unless specified to the contrary.
[0116] The characteristics of the various embodiments of the
invention can be combined with one another.
[0117] In particular, the shot of FIGS. 1 and 3 can optionally be
used in the examples of FIGS. 4 to 19.
[0118] The sonotrode of the example of FIGS. 4 to 5 can optionally
be used in the examples of FIGS. 6 to 19.
[0119] Although the present invention herein has been described
with reference to particular embodiments, it is to be understood
that these embodiments are merely illustrative of the principles
and applications of the present invention. It is therefore to be
understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised
without departing from the spirit and scope of the present
invention as defined by the appended claims.
* * * * *