U.S. patent application number 12/911099 was filed with the patent office on 2012-04-26 for system and method for near net shape forging.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Manu Mathai, Raymond Joseph Stonitsch.
Application Number | 20120096915 12/911099 |
Document ID | / |
Family ID | 45023554 |
Filed Date | 2012-04-26 |
United States Patent
Application |
20120096915 |
Kind Code |
A1 |
Mathai; Manu ; et
al. |
April 26, 2012 |
SYSTEM AND METHOD FOR NEAR NET SHAPE FORGING
Abstract
A method for near net shape forging a titanium component
includes heating a titanium billet to a temperature in the
alpha-beta temperature range and extruding the titanium billet into
a first die having a temperature approximately 500.degree. F. below
the temperature of the titanium billet. A system for near net shape
forging a titanium component includes a titanium billet having a
temperature in the alpha-beta temperature range and a punch in
contact with the titanium billet. A first die proximate to the
titanium billet for receiving the titanium billet has a temperature
approximately 500.degree. F. below the temperature of the titanium
billet.
Inventors: |
Mathai; Manu; (Chennai,
IN) ; Stonitsch; Raymond Joseph; (Simpsonville,
SC) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
45023554 |
Appl. No.: |
12/911099 |
Filed: |
October 25, 2010 |
Current U.S.
Class: |
72/342.1 ;
72/364 |
Current CPC
Class: |
C22F 1/183 20130101;
B21J 5/06 20130101; F05D 2230/25 20130101; Y02T 50/676 20130101;
B21C 23/002 20130101; B21J 5/02 20130101; Y02T 50/60 20130101; Y02T
50/671 20130101; F01D 5/18 20130101 |
Class at
Publication: |
72/342.1 ;
72/364 |
International
Class: |
B21D 37/16 20060101
B21D037/16; B21D 31/00 20060101 B21D031/00 |
Claims
1. A method for near net shape forging a titanium component
comprising: a. heating a titanium billet to a temperature in the
alpha-beta temperature range; and b. extruding the titanium billet
into a first die having a temperature approximately 500.degree. F.
below the temperature of the titanium billet.
2. The method as in claim 1, further comprising extruding the
titanium billet into the first die having a temperature
approximately 600.degree. F. below the temperature of the titanium
billet.
3. The method as in claim 1, further comprising adiabatically
heating the titanium billet.
4. The method as in claim 1, further comprising maintaining the
temperature of the titanium billet in the alpha-beta temperature
range.
5. The method as in claim 1, further comprising incrementally
moving a first section of the first die against the titanium
billet.
6. The method as in claim 5, further comprising incrementally
moving a second section of the first die against the titanium
billet.
7. The method as in claim 1, further comprising extruding the
titanium billet into a second die, wherein the second die has a
temperature approximately 500.degree. F. below the temperature of
the titanium billet.
8. The method as in claim 7, further comprising incrementally
moving a first section of the second die against the titanium
billet.
9. The method as in claim 8, further comprising incrementally
moving a second section of the second die against the titanium
billet.
10. A method for near net shape forging a titanium component
comprising: a. heating a titanium billet to a temperature in the
alpha-beta temperature range; and b. creating a differential
temperature between the titanium billet and a first die of
approximately 500.degree. F.
11. The method as in claim 10, further comprising adiabatically
heating the titanium billet.
12. The method as in claim 10, further comprising extruding the
titanium billet into the first die.
13. The method as in claim 10, further comprising extruding the
titanium billet into a second die, wherein the second die has a
temperature approximately 500.degree. F. below the temperature of
the titanium billet.
14. A system for near net shape forging a titanium component
comprising: a. a titanium billet, wherein the titanium billet has a
temperature in the alpha-beta temperature range; b. a punch in
contact with the titanium billet; and c. a first die proximate to
the titanium billet for receiving the titanium billet, wherein the
first die has a temperature approximately 500.degree. F. below the
temperature of the titanium billet.
15. The system as in claim 14, wherein the first die has a
temperature approximately 600.degree. F. below the temperature of
the titanium billet.
16. The system as in claim 14, wherein the first die is configured
to move with respect to the punch.
17. The system as in claim 14, wherein the first die comprises a
first section and a second section.
18. The system as in claim 17, wherein the first section of the
first die is configured to move independently of the second section
of the first die.
19. The system as in claim 17, wherein only a portion of the first
die is in contact with the titanium billet at a time.
20. The system as in claim 14, further comprising a second die that
receives the titanium billet from the first die.
Description
FIELD OF THE INVENTION
[0001] The present invention generally involves a system and method
for near net shape forging. In particular, embodiments of the
present invention provide a system and process for near net shape
forging titanium components in the alpha-beta temperature
range.
BACKGROUND OF THE INVENTION
[0002] Commercial equipment often includes components made from
titanium or titanium alloys. For example, compressors and turbines
typically include alternating stages of stationary vanes and
rotating blades. In aircraft engines and gas turbines, the
compressor and turbine rotating blades often have relatively
complex and curved profiles forged from high strength, light weight
titanium or titanium alloys. In particular, the rotating blades may
be forged from titanium alloys in the alpha-beta temperature
range.
[0003] Near net shape forging is technique in which the initial
shape of an item is very close ("near") to the final ("net") shape.
Near net shape forging, for example, deforms a billet into an
initial shape requiring little or no surface machining or grinding
to achieve a final shape. However, near net shape forging of
titanium alloys in the alpha-beta temperature range typically
requires expensive die materials that can withstand the elevated
forging temperatures of the alpha-beta temperature range.
Specifically, the die temperature is typically maintained at or
near the billet temperature of approximately 1,600.degree. F. to
1,800.degree. F., depending on the particular titanium alloy,
during near net shape forging of titanium alloys in the alpha-beta
temperature range to minimize any cooling of the titanium billet
during the forging process. The near net shape forging process is
typically performed in a vacuum to maintain near isothermal
conditions between the die and the billet during the forging
process. The high cost of the die and associated equipment often
prevents near net shape forging from being a cost-effective option
for forging titanium components in the alpha-beta temperature
range. As a result, compressor and turbine rotating blades made
from titanium and titanium alloys are often forged in a multi-step
process that includes open die forging, closed die forging, one or
more heat treatments, and expensive finishing. This multi-step
process results in a large amount of material wastage, additional
finishing costs, and less than optimal grain structure in the
finished product.
[0004] Presently, no forging technology exists for near net shape
forging of titanium or titanium alloys in the alpha-beta
temperature range without requiring elevated die temperatures at or
near the alpha-beta temperature range. Therefore, an improved
method for near net shape forging of titanium and titanium alloys
in the alpha-beta temperature range that does not require die
temperatures to be at or near the alpha-beta temperature range
would be useful.
BRIEF DESCRIPTION OF THE INVENTION
[0005] Aspects and advantages of the invention are set forth below
in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
[0006] One embodiment of the present invention is a method for near
net shape forging a titanium component. The method includes heating
a titanium billet to a temperature in the alpha-beta temperature
range and extruding the titanium billet into a first die having a
temperature approximately 500.degree. F. below the temperature of
the titanium billet.
[0007] Another embodiment of the present invention is a method for
near net shape forging a titanium component that includes heating a
titanium billet to a temperature in the alpha-beta temperature
range and creating a differential temperature between the titanium
billet and a first die of approximately 500.degree. F.
[0008] The present invention also includes a system for near net
shape forging a titanium component. The system includes a titanium
billet having a temperature in the alpha-beta temperature range and
a punch in contact with the titanium billet. A first die proximate
to the titanium billet for receiving the titanium billet has a
temperature approximately 500.degree. F. below the temperature of
the titanium billet.
[0009] Those of ordinary skill in the art will better appreciate
the features and aspects of such embodiments, and others, upon
review of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] A full and enabling disclosure of the present invention,
including the best mode thereof to one skilled in the art, is set
forth more particularly in the remainder of the specification,
including reference to the accompanying figures, in which:
[0011] FIGS. 1, 2, and 3 illustrate a system for near net shape
forging according to one embodiment of the present invention;
[0012] FIGS. 4 and 5 illustrate a system for near net shape forging
according to second embodiment of the present invention;
[0013] FIGS. 6, 7, and 8 illustrate a system for near net shape
forging according to a third embodiment of the present invention;
and
[0014] FIGS. 9 and 10 illustrate a system for near net shape
forging according to a fourth embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Reference will now be made in detail to present embodiments
of the invention, one or more examples of which are illustrated in
the accompanying drawings. The detailed description uses numerical
and letter designations to refer to features in the drawings. Like
or similar designations in the drawings and description have been
used to refer to like or similar parts of the invention.
[0016] Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that modifications and
variations can be made in the present invention without departing
from the scope or spirit thereof For instance, features illustrated
or described as part of one embodiment may be used on another
embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
[0017] Various embodiments of the present invention provide a
system and method for near net shape forging titanium, including
titanium alloys, in the alpha-beta temperature range. In particular
embodiments, a titanium billet in the alpha-beta temperature range
is radially and sequentially extruded through or into a die while
the temperature of the die is maintained well below the alpha-beta
temperature range for titanium. The rate of extrusion can be
controlled to regulate the amount of adiabatic heating created in
the billet to approximately equal the amount of heat lost or
transferred to the lower temperature die. In addition, the rate and
sequence of the extrusion process may be controlled to impart a
desired grain size and flow and/or residual compressive stress in
the deformed billet. The grain size and flow directly affect cycle
fatigue properties of the deformed billet, and the residual
compressive stresses enhance the crack growth resistance of the
deformed billet. In combination, the sequential extrusion process
thus allows a single deformed billet to have grains with different
sizes and orientations and residual compressive stresses at
different locations in the deformed billet. Although various
embodiments of the present invention are described and illustrated
in the context of a titanium billet forged into a dovetail or blade
of a compressor or turbine blade, one of ordinary skill in the art
will readily appreciate that the present invention is not limited
to a particular billet material or end product unless specifically
recited in the claims.
[0018] FIGS. 1, 2, and 3 illustrate a system 10 and method for near
net shape forging according to one embodiment of the present
invention. As shown, the system 10 generally includes a billet 12,
a punch 14, an extrusion container 16, and a die 18. The billet 12
may comprise titanium or titanium alloy heated to a temperature in
the alpha-beta temperature range using any heat source known to one
of ordinary skill in the art. The actual temperature of the
alpha-beta temperature range depends on the particular titanium
alloy being used and may be approximately 1,600-1,800.degree. F.,
depending on the particular titanium alloy being used. The punch 14
is in contact with the billet 12 and may be connected to any
suitable press (not shown) known in the art for supplying a desired
force or strain to the punch 14 to extrude the billet 12 through
the extrusion container 16 into or through the die 18. The
extrusion container 16 provides a volume for holding the billet 12
prior to extrusion and may comprise any suitable structure capable
of withstanding temperatures in the alpha-beta temperature range
for the particular titanium alloy being used. The die 18 is
proximate to the billet 12 for receiving the billet 12 and provides
the desired shape for the forged billet 12. The die 18 may comprise
any suitable structure capable of withstanding temperatures up to
approximately 500-1,300.degree. F.
[0019] As shown in FIG. 1, the billet 12 may be contained within
the extrusion container 16. The punch 14 may be located at a first
opening 20, and the die 18 may be located at a second opening 22 of
the extrusion container 16. In this manner, force applied to the
punch 14 may move the punch 14 with respect to the extrusion
container 16 and die 18 to extrude the billet 12 into or through
the die 18, as progressively shown in FIGS. 2 and 3.
[0020] The die 18 may have a temperature substantially lower than
the temperature of the billet 12 to reduce the cost of materials
required for the die 18. For example, the die 18 may have a
temperature approximately 500.degree. F., 600.degree. F.,
1,000.degree. F., or more below the temperature of the billet 12,
creating a corresponding differential temperature between the die
18 and the billet 12 of approximately 500.degree. F., 600.degree.
F., 1,000.degree. F., or more. The temperature difference between
the die 18 and the billet 12 results in conductive and/or
convective cooling of the billet 12. The process parameters of the
system 10 may be controlled or adjusted to regulate the amount of
adiabatic heating created in the billet 12 during the extrusion
process. For example, the size or diameter of the extrusion
container 16 and/or the strain rate applied by the punch 14 may be
controlled or adjusted to change the amount of adiabatic heating
created in the billet 12 during the extrusion process to
approximately match the heat transferred to the die 18. Depending
on the particular system, titanium alloy, size of the die 18, and
various other process parameters, adiabatic heating may increase
the temperature of the billet 12 by 50.degree. F., 70.degree. F.,
or more. As a result, the system 10 maintains the temperature of
the billet 12 in the alpha-beta temperature range during the
extrusion process, producing a near net shape titanium dovetail 24,
seen in FIG. 3, having a desired grain size and direction and
requiring little or no grinding or other finishing process.
[0021] FIGS. 4 and 5 and 6, 7, and 8 illustrate a system 30 and
method for intermediate forging according to alternate embodiments
of the present invention. The system 30 shown in FIGS. 4 and 5 and
FIGS. 6, 7, and 8 may be used in concert with or independent of the
system 10 previously described and illustrated with respect to
FIGS. 1, 2, and 3. For example, the titanium dovetail 24 produced
using the system 10 described illustrated with respect to FIGS. 1,
2, and 3 may be further forged using either embodiment illustrated
in FIGS. 4 and 5 or FIGS. 6, 7, and 8. Alternately, the system 30
illustrated in FIGS. 4 and 5 or FIGS. 6, 7, and 8 may be used as a
stand alone system for forging an intermediate titanium billet.
[0022] The system 30 shown in FIGS. 4 and 5 and FIGS. 6, 7, and 8
generally includes a billet 32 as previously described with respect
to FIGS. 1, 2, and 3. Specifically, the billet 32 may comprise
titanium or titanium alloy heated to a temperature in the
alpha-beta temperature range using any heat source known to one of
ordinary skill in the art. In addition, the system 30 includes a
stationary punch 34 and a die 36. The stationary punch 34 is in
contact with and holds the billet 32 in place.
[0023] As shown in FIGS. 4 and 6, the die 36 is proximate to the
billet 32 for receiving the billet 32 and provides the desired
shape for the forged billet 32. The die 36 may comprise any
suitable structure capable of withstanding temperatures up to
approximately 500-1,300.degree. F. and may include multiple
sections that may move sequentially and/or incrementally
independent of one another. For example, as shown in FIGS. 4 and 5
and 6, 7, and 8, the die 36 may include a first section 38 and a
second section 40. A press (not shown) may incrementally and/or
sequentially move the first and second sections 38, 40 with respect
to the stationary punch 34 to progressively extrude the billet 32
into or through the die 36. By incrementally and/or sequentially
applying pressure to multiple sections of the die 36, the contact
points between the die 36 and the billet 32 are reduced. As a
result, the strain rates needed to forge the billet 32 are reduced,
allowing a smaller capacity press to provide the desired strain
rate for forging the billet 32. In addition, the incremental and/or
sequential movement of the multiple sections of the die 36 creates
desirable residual compressive stresses in the billet 32 that
enhance crack growth resistance in the forged billet 32.
[0024] As with the die 18 described with respect to the first
embodiment, the die 36 shown in FIGS. 4 and 5 and 6, 7, and 8 may
have a temperature substantially lower than the temperature of the
billet 32 to reduce the cost of materials required for the die 36.
For example, the die 36 may have a temperature approximately
500.degree. F., 600.degree. F., 1,000.degree. F., or more below the
temperature of the billet 32, creating a corresponding differential
temperature between the die 36 and the billet 32 of approximately
500.degree. F., 600.degree. F., 1,000.degree. F., or more. The
temperature difference between the die 36 and the billet 32 again
results in conductive and/or convective cooling of the billet 32.
As a result, the process parameters of the system 30 may again be
controlled or adjusted to regulate the amount of adiabatic heating
created in the billet 32 during the extrusion process. For example,
the strain rate applied by the press alternately and/or
sequentially to the first and second sections 38, 40 may be
controlled or adjusted to change the amount of adiabatic heating
created in the billet 32 during the extrusion process. Depending on
the particular system, titanium alloy, size and number of sections
38, 40 of the die 36, and various other process parameters,
adiabatic heating may increase the temperature of the billet 32 as
needed to approximately match the heat transferred to the die 36.
As a result, the system 30 again maintains the temperature of the
billet 32 in the alpha-beta temperature range during the extrusion
process, producing the intermediate billet 32 shown in FIGS. 5 and
8.
[0025] FIGS. 9 and 10 illustrate a system 50 for near net shape
forging according to a fourth embodiment of the present invention.
As with the previous embodiments, the system 50 shown in FIGS. 9
and 10 may be used in concert with or independent of the previously
described and illustrated systems 10, 30. For example, the
intermediate billet 32 produced using the system 30 described and
illustrated with respect to FIGS. 4 and 5 or 6, 7, and 8 may be
further forged using the embodiment illustrated in FIGS. 9 and 10
to produce a near net shape component.
[0026] The system 50 shown in FIGS. 9 and 10 generally includes a
billet 52, stationary punch 54, and die 56 as previously described
with respect to the embodiment shown in FIGS. 4 and 5 and 6, 7, and
8. Specifically, the billet 52 may comprise titanium or titanium
alloy heated to a temperature in the alpha-beta temperature range
using any heat source known to one of ordinary skill in the art. In
addition, the stationary punch 54 is in contact with and holds the
billet 52 in place, and the die 56 is again proximate to the billet
52 for receiving the billet 52.
[0027] The die 56 may comprise any suitable structure capable of
withstanding temperatures up to approximately 500-1,300.degree. F.
and may include multiple sections that may move sequentially and/or
incrementally independent of one another. For example, as shown in
FIGS. 9 and 10, the die 56 may include a first section 58 and a
second section 60. A press (not shown) may incrementally and/or
sequentially move the first and second sections 58, 60 with respect
to the stationary punch 54 to progressively extrude the billet 52
into the die 56. By incrementally and/or sequentially applying
pressure to multiple sections of the die 56, the contact points
between the multiple sections of the die 56 and the billet 52 are
reduced. As a result, the strain rates needed to forge the billet
52 are reduced, allowing a smaller capacity press to provide the
desired strain rate for forging the billet 52. In addition, the
incremental and/or sequential movement of the multiple sections of
the die 56 creates desirable residual compressive stresses in the
billet 56 that enhance crack growth resistance in the forged billet
52.
[0028] As with the previous embodiments, the die 56 may have a
temperature substantially lower than the temperature of the billet
52 to reduce the cost of materials required for the die 56. For
example, the die 56 may have a temperature approximately
500.degree. F., 600.degree. F., 1,000.degree. F., or more below the
temperature of the billet 52, creating a corresponding differential
temperature between the die 56 and the billet 52 of approximately
500.degree. F., 600.degree. F., 1,000.degree. F., or more. The
temperature difference between the die 56 and the billet 52 again
results in conductive and/or convective cooling to the billet 52.
As a result, the process parameters of the system 50 may again be
controlled or adjusted to regulate the amount of adiabatic heating
produced in the billet 52 during the extrusion process. For
example, the strain rate applied by the press alternately and/or
sequentially to the first and second sections 58, 60 may be
controlled or adjusted to change the amount of adiabatic heating
created in the billet 52 during the extrusion process. Depending on
the particular system, titanium alloy, size and number of sections
58, 60 of the die 56, and various other process parameters,
adiabatic heating may increase the temperature of the billet 52 as
needed to approximately match the heat transferred to the die 56.
As a result, the system 50 again maintains the temperature of the
billet 52 in the alpha-beta temperature range during the extrusion
process, producing the near net shape billet 52, shown in FIG. 10,
having a desired grain size and orientation and residual
compressive stresses and requiring little or no grinding or other
finishing process.
[0029] One of ordinary skill in the art will readily appreciate
that the previously described embodiments may be combined
sequentially in any order to provide a system and method for
forging a near net shape titanium component having complex curves.
For example, the titanium billet 12 forged using the first die 18
described and illustrated with respect to FIGS. 1, 2, and 3 may be
subsequently forged using the second die 36 described with respect
to FIGS. 4 and 5 or 6, 7, and 8, and the intermediate titanium
billet 32 may be subsequently forged using the third die 56
described with respect to FIGS. 9 and 10. As previously described,
the sequence, amount, and strain rate applied to each die 18, 36,
56 may be adjusted or controlled to regulate the amount of
adiabatic heat created in the forged billet, thus allowing the use
of less expensive dies while still maintaining the temperature of
the billet in the alpha-beta temperature range. In addition, the
sequence, amount, and strain rate applied to each die 18, 36, 56
may be adjusted or controlled to produce a desired size, location,
and orientation of grain structures and/or residual compressive
stresses in the various titanium billets 12, 32, 52. As a result,
the combination of embodiments previously described and illustrated
may produce a titanium product with multiple zones having different
grain and compressive stress characteristics without requiring
additional finishing or processing. Lastly, the incremental and/or
sequential movement of the dies results in reduced contact points
between the dies and the billet, avoiding the need for presses
having increased strain capabilities.
[0030] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other and examples are intended to be within the
scope of the claims if they include structural elements that do not
differ from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *