U.S. patent application number 13/193730 was filed with the patent office on 2013-01-31 for die casting system and method.
The applicant listed for this patent is Mario P. Bochiechio, John Joseph Marcin, Dilip M. Shah. Invention is credited to Mario P. Bochiechio, John Joseph Marcin, Dilip M. Shah.
Application Number | 20130025816 13/193730 |
Document ID | / |
Family ID | 46603669 |
Filed Date | 2013-01-31 |
United States Patent
Application |
20130025816 |
Kind Code |
A1 |
Bochiechio; Mario P. ; et
al. |
January 31, 2013 |
DIE CASTING SYSTEM AND METHOD
Abstract
A die casting system includes a die having a plurality of die
elements that define a die cavity. A charge of material is received
in the die cavity. The charge of material may comprises a
refractory metal intermetallic composite based material system. The
charge of material may also comprise a composite material.
Inventors: |
Bochiechio; Mario P.;
(Vernon, CT) ; Marcin; John Joseph; (Marlborough,
CT) ; Shah; Dilip M.; (Glastonbury, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bochiechio; Mario P.
Marcin; John Joseph
Shah; Dilip M. |
Vernon
Marlborough
Glastonbury |
CT
CT
CT |
US
US
US |
|
|
Family ID: |
46603669 |
Appl. No.: |
13/193730 |
Filed: |
July 29, 2011 |
Current U.S.
Class: |
164/312 ;
164/284 |
Current CPC
Class: |
B22D 17/10 20130101;
B22D 21/06 20130101; B22D 21/005 20130101; B22D 21/025 20130101;
B22D 17/00 20130101; B22D 25/02 20130101; C22C 27/02 20130101; B22D
21/022 20130101; B22D 17/2209 20130101; B22D 17/2218 20130101 |
Class at
Publication: |
164/312 ;
164/284 |
International
Class: |
B22D 17/00 20060101
B22D017/00; B22D 17/20 20060101 B22D017/20 |
Claims
1. A die casting system, comprising: a die having a plurality of
die elements that define a die cavity; a charge of material
communicated into said die cavity, wherein said charge of material
comprises a refractory metal intermetallic composite based material
system.
2. The die casting system as recited in claim 1, comprising a shot
tube in fluid communication with said die cavity, and a shot tube
plunger moveable within said shot tube to communicate said charge
of material into said die cavity.
3. The die casting system as recited in claim 1, wherein a portion
of said die casting system includes a highly conductive
material.
4. The die casting system as recited in claim 3, wherein said die
elements include said highly conductive material.
5. The die casting system as recited in claim 3, wherein said
highly conductive material includes a thermal conductivity of at
least of at least 310 W/m*K and a melting temperature of at least
960.degree. C. (1760.degree. F.).
6. The die casting system as recited in claim 1, comprising a
heating system that selectively heats said die elements.
7. The die casting system as recited in claim 1, comprising a
cooling system that selectively cools said die elements.
8. The die casting system as recited in claim 7, wherein said
cooling system includes liquid metal cooling.
9. (canceled)
10. The die casting system as recited in claim 1, wherein said
refractory metal intermetallic composite based material system
includes niobium silicide (NbSi).
11. The die casting system as recited in claim 1, wherein said
refractory metal intermetallic composite based material system
includes molybdenum di-silicide (NbSi2).
12. The die casting system as recited in claim 1, wherein said
refractory metal intermetallic composite based material system
includes a composite material selected from the group consisting of
Nb.sub.5Si.sub.3+NbO+SiO.sub.2;
NbSi.sub.2+Nb.sub.5Si.sub.3+SiO.sub.2;
TaSi.sub.2+Ta.sub.5Si.sub.3+SiO.sub.2; W.sub.5Si.sub.3+W+SiO.sub.2;
and WSi.sub.2+W.sub.5Si.sub.3+SiO.sub.2.
13-15. (canceled)
16. A die casting system, comprising: a die having at least one die
elements that defines a die cavity; a charge of material
communicated into said die cavity, wherein said charge of material
comprises a composite material selected from the group consisting
of niobium silicide, molybdenum di-silicide,
Nb.sub.5Si.sub.3+NbO+SiO.sub.2,
NbSi.sub.2+Nb.sub.5Si.sub.3+SiO.sub.2,
TaSi.sub.2+Ta.sub.5Si.sub.3+SiO.sub.2, W.sub.5Si.sub.3+W+SiO.sub.2,
and WSi.sub.2+W.sub.5Si.sub.3+SiO.sub.2.
17. The die casting system as recited in claim 16, wherein said die
elements includes a highly conductive material.
18-20. (canceled)
21. The die casting system as recited in claim 1, comprising a
vacuum chamber and a vacuum source that applies a vacuum to said
vacuum chamber.
22. The die casting system as recited in claim 1, comprising a
heating system that selectively heats said plurality of die
elements and a cooling system that selectively cools said plurality
of die elements.
23. The die casting system as recited in claim 22, wherein said
heating system includes a die heater and said cooling system
includes liquid metal cooling.
Description
BACKGROUND
[0001] This disclosure relates generally to casting, and more
particularly to a die casting system and method.
[0002] Casting is a known technique used to yield near net-shaped
components. For example, investment casting is often used in the
gas turbine engine industry to manufacture blades, vanes and other
components having relatively complex geometries. A component is
investment cast by pouring molten metal into a ceramic shell having
a cavity in the shape of the component to be cast. Generally, the
shape of the component is derived from a wax or SLA pattern that
defines the shape of the component. The investment casting process
is capital intensive, requires a significant amount of manual
labor, and can be time intensive.
[0003] Die casting offers another casting technique. Die casting
involves injecting molten metal directly into a reusable die to
yield a near net-shaped component. The tooling of the die casting
system, including the die, the shot tube and the shot tube plunger,
are subjected to relatively high thermal loads and stresses during
the die casting process.
SUMMARY
[0004] A die casting system includes a die having a plurality of
die elements that define a die cavity. A charge of material is
received in the die cavity. The charge of material comprises a
refractory metal intermetallic composite based material system.
[0005] In another exemplary embodiment, a die casting system
includes a die having a plurality of die elements that define a die
cavity. A charge of material is received in the die cavity. The
charge of material can include a composite material such as niobium
silicide, molybdenum di-silicide, Nb.sub.5Si.sub.3+NbO+SiO.sub.2,
NbSi.sub.2+Nb.sub.5Si.sub.3+SiO.sub.2,
TaSi.sub.2+Ta.sub.5Si.sub.3+SiO.sub.2, W.sub.5Si.sub.3+W+SiO.sub.2,
and WSi.sub.2+W.sub.5Si.sub.3+SiO.sub.2.
[0006] An exemplary method of die casting a component includes
injecting a charge of material into a die having a plurality of die
elements that define a die cavity configured to receive the charge
of material. The charge of material comprises a refractory metal
intermetallic composite based material system.
[0007] The various features and advantages of this disclosure will
become apparent to those skilled in the art from the following
detailed description. The drawings that accompany the detailed
description can be briefly described as follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 illustrates a die casting system.
[0009] FIG. 2A illustrates the die casting system of FIG. 1 during
casting of the component.
[0010] FIG. 2B illustrates the die casting system of FIG. 1 upon
separation from the casting component.
[0011] FIG. 3 illustrates additional features that can be
incorporated into a die casting system.
[0012] FIG. 4 illustrates a component cast in a die casting
process.
DETAILED DESCRIPTION
[0013] FIG. 1 illustrates an example die casting system 50
including a reusable die 52 having a plurality of die elements 54,
56 that function to cast a component 55 (See FIG. 4). Although two
die elements 54, 56 are depicted in FIG. 1, it should be understand
that the die 52 could include a greater or fewer number of die
elements, as well as other parts and configurations.
[0014] The die 52 is assembled by positioning the die elements 54,
56 together and holding the die elements 54, 56 at a desired
positioning via a mechanism 58. The mechanism 58 could include a
clamping mechanism of appropriate hydraulic, pneumatic,
electromechanical and/or other configurations. The mechanism 58
also separates the die elements 54, 56 subsequent to casting.
[0015] The die elements 54, 56 define internal surfaces 62 that
cooperate to define a die cavity 60. A shot tube 64 is in fluid
communication with the die cavity 60 via one or more ports 66
located in the die element 54, the die element 56 or both. A shot
tube plunger 68 is received within the shot tube 64 and is moveable
between a retracted and injected position (in the direction of
arrow A) within the shot tube 64 by a mechanism 80. A shot rod 31
extends between the mechanism 80 and the shot tube plunger 68. The
mechanism 80 could include a hydraulic assembly or other suitable
system including, but not limited to, pneumatic, electromechanical,
hydraulic or any combination of the systems.
[0016] The shot tube 64 is positioned to receive a charge of
material M from a melting unit 82, such as a crucible, for example.
The melting unit 82 can utilize any known technique for melting an
ingot of metallic material to prepare the charge of material M for
delivery to the shot tube 64, including but not limited to, vacuum
induction melting, electron beam melting, induction skull melting
and resistance melting. The charge of material M is melted into
molten metal in the melting unit 82 at a location that is separate
from the shot tube 64 and the die cavity 60. In this example, the
melting unit 82 is positioned in close proximity to the shot tube
64 to reduce the required transfer distance between the charge of
material M and the shot tube 64.
[0017] The charge of material M is transferred from the melting
unit 82 to the shot tube 64 in a known manner, such as pouring the
charge of material M into a pour hole 63 in the shot tube 64, for
example. A sufficient amount of molten metal is poured into shot
tube 64 to fill the die cavity 60. The shot tube plunger 68 is
actuated to inject the charge of material M under pressure from the
shot tube 64 into the die cavity 60 to cast a component 55.
Although a single component 55 is depicted, the die casting system
50 could be configured to cast multiple components in a single
shot.
[0018] Although not necessary, at least a portion of the die
casting system 50 can be positioned within a vacuum chamber 90 that
includes a vacuum source 92. A vacuum is applied in the vacuum
chamber 90 via the vacuum source 92 to render a vacuum die casting
process. The vacuum chamber 90 provides a non-reactive environment
for the die casting system 50 and reduces reaction, contamination
or other conditions that could detrimentally affect the quality of
the die cast component, such as excess porosity in the cast
component resulting from exposure to air.
[0019] In one example, the vacuum chamber 90 is maintained at a
pressure 5.times.10.sup.-3 Ton (0.66 Pascal) and 1.times.10.sup.-6
Torr (0.000133 Pascal), although other pressures are contemplated.
The actual pressure of the vacuum chamber 90 will vary based on the
type of component 55 cast, among other conditions and factors. In
the illustrated example, each of the melting unit 82, the shot tube
64 and the die 52 are positioned within the vacuum chamber 90
during the die casting process such that the melting, injecting and
solidifying of the charge of material M are each performed under
vacuum. In another example, the vacuum chamber 90 is vacuum filled
with an inert gas, such as argon, for example.
[0020] The example die casting system 50 depicted by FIG. 1 is
illustrative only and could include a greater or fewer number of
sections, parts and/or components. This disclosure extends to all
forms of die casting, including but not limited to, horizontal,
vertical, inclined or other die casting configurations.
[0021] FIGS. 2A and 2B illustrate portions of the die casting
system 50 during casting (FIG. 3A) and after the die elements 54,
56 separate (FIG. 3B). After the charge of material M solidifies
within the die cavity 70, the die elements 54, 56 are disassembled
relative to the component 55 by opening the die 52 via the
mechanism 58. In one example, ejector pins 84 are used to remove
the components 55 from the die cavity 60.
[0022] A die release agent may be applied to the die elements 54,
56 of the die 52 prior to injection to achieve a simpler release of
the component 55 from the die 52 post-solidification. The cast
component 55 may include an equiaxed structure upon solidification,
or could include other structures. An equiaxed structure includes a
randomly oriented grain structure having multiple grains.
[0023] In one example, a composite material is used to die cast the
component 55. In this disclosure, "composite" is defined as a
refractory metal intermetallic composite (or, RMIC). RMIC's contain
a member or members of the family of refractory elements. These
elements include tungsten, rhenium, tantalum, molybdenum, and
niobium. These elements are combined with an intermetallic element
such as silicon. Example composites include, but are not limited
to, niobium silicide (NbSi) and molybdenum di-silicide (MoSi2).
Further included are the following example composites:
Nb.sub.5Si.sub.3+NbO+SiO.sub.2;
NbSi.sub.2+Nb.sub.5Si.sub.3+SiO.sub.2;
TaSi.sub.2+Ta.sub.5Si.sub.3+SiO.sub.2; W.sub.5Si.sub.3+W+SiO.sub.2;
and WSi.sub.2+W.sub.5Si.sub.3+SiO.sub.2.
[0024] Additional intermetallic compounds include, but are not
limited to, Nickel Aluminides of general composition NiAl and Ni3Al
(but can contain alloying elements such as: Co, Cr, Pt, Si, Re, Rh,
Ta, Y, Er, Gd, Zr and/or Hf); Titanium Aluminide of the general
compositions TiAl, TiAl2, TiAl3 (but can contain alloying elements
such as Mn, V, Nb, Ta, Fe, Co, Cr, Ni, B, W, Mo, Cu, Zr, and/or
Si); and Platinum Aluminide of general composition PtAl (but can
contain alloying elements such as, but not limited to, Ni, Co, Cr,
Pt, Si, Rh, Ta, Y, Er, Gd, and/or Hf).
[0025] Die casting components using a charge of material such as
the RMIC's noted above provides an improved casting process without
the need to develop or reengineer the ceramic systems that are used
in a traditional investment casting process.
[0026] FIG. 3 illustrates additional features that can be
incorporated into the die casting system 50. The die elements 54,
56 can be selectively heated with a heating system 100, such as a
die heater, if necessary. In addition, die inserts of the die
elements 54, 56 can include layers of a highly conductive material
to aid in the temperature control of the die inserts. Example
highly conductive materials could include a thermal conductivity of
at least 310 W/m*K and a melting temperature of at least
960.degree. C. (1760.degree. F.). Materials such as copper, gold
and silver are examples of such highly conductive materials that
can be used in the construct of portions of the die elements 54,
56. The highly conductive material rapidly conducts heat away from
the die elements 54, 56 during the casting process to extend
tooling life.
[0027] The die elements 54, 56 can also be selectively cooled with
a cooling system 104 as necessary due to the extreme heat
experienced during the casting process. For example, a die casting
hot oil technology can be used, or other radiative or conductive
cooling techniques such as liquid metal cooling, in order to cool
the die elements 54, 56 and a die base 102 during the casting
process.
[0028] FIG. 4 illustrates an example component 55 that can be cast
in a die casting process. In this example, the component 55 is an
airfoil for a gas turbine engine. However, this disclosure is not
limited to the casting of airfoils. For example, the example die
casting system 50 of this disclosure may be utilized to cast
aeronautical components including blades, vanes, combustor panels,
blade outer air seals (boas), or any other components that could be
subjected to extreme environments, including non-aeronautical
components.
[0029] The die cast component 55 can include an internal geometry
38 defined within the component 55 (i.e., the component 55 is at
least partially hollow). In this example, the internal geometry 38
defines a microcircuit cooling scheme for a turbine vane. However,
the internal geometry 38 could also define other advanced cooling
schemes to facilitate additional heat transfer. Additionally,
weight reduction tongues (i.e., voids) can be included to reduce
the rotational inertia and/or weight of the final component.
[0030] The component 55, including its internal geometry 38, can be
cast using the example die casting system 50 described above. Die
casting of the component 55 with the materials noted above allows
for the production of a fine, uniform grain size that will improve
the properties and materials. Furthermore, solidification rates
will be increased significantly by transitioning refractory metal
alloys and/or composite to die casting. Additionally, the rapid
melting of the charge of material from ingot stock reduces the
potential for reactivity with the die casting system 50 tooling due
to the ability of the die casting tooling to disperse heat away
from the final casting geometry. In other words, the bulk of the
die tooling is able to absorb the heat and effectively move it to
other areas of the die.
[0031] The foregoing description shall be interpreted as
illustrative and not in any limiting sense. A worker of ordinary
skill in the art would understand that certain modifications could
come within the scope of this disclosure. For these reasons, the
following claims should be studied to determine the true scope and
content of this disclosure.
* * * * *