Note: Descriptions are shown in the official language in which they were submitted.
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BALLISTIC APPLICATIONS OF COMPOSITE MATERIALS
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001]
This application is a continuation of, and claims priority to, U.S. Patent
Application No. 13/070,406, filed on March 23, 2011, entitled "Ballistic
Applications
of Composite Materials," U.S. Patent Application No. 13/070,383 filed, on
March 23,
2011, entitled "Composite Components Formed with Loose Ceramic Material," and
U.S. Patent Application No. 13/070,418, filed on March 23, 2011, entitled
"Composite
Components Formed by Coating a Mold with Ceramic Material," all of which are
hereby incorporated by reference in their entireties.
BACKGROUND
[0002]
Wear or impact resistant components are desirable in a variety of industrial,
commercial, and military applications. For example, mining, construction,
heavy
equipment, automotive, military, and other applications rely on components
that are
resistant to wear and impact.
[0003]
Recently, composite components formed of two materials having different
material properties have been used. For example, a composite component may be
made by combining a first material having a high hardness with a second
material
having a high toughness, to produce a composite component having
characteristics of
both materials (i.e., high hardness and toughness).
[0004]
However, manufacturing composite components is often challenging due to
the different properties of materials used to form the composite component.
For
example, different materials often have different coefficients of thermal
expansion,
different densities, different melting points, etc. A manufacturing process
that works
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well for one material may not be compatible with another material. For
example, if
two materials have different coefficients of thermal expansion, they will
expand or
contract at different rates. If the difference between coefficients of thermal
expansion
is significant, cracks and/or voids may form as a composite component made
from the
materials cools, thereby detracting from the performance of the composite
material.
[0005] Thus, there remains a need to develop new composite materials
and
methods of manufacturing such composite materials.
BRIEF SUMMARY
[0006]
This Brief Summary is provided to introduce simplified concepts relating
to techniques for casting composite components including ceramic material and
a base
metal, which are further described below in the Detailed Description. This
Summary
is not intended to identify essential features of the claimed subject matter,
nor is it
intended for use in determining the scope of the claimed subject matter.
[0007]
This disclosure relates to composite components that are subject to wear (so
called "wear parts") and/or impacts and techniques for forming such
components.
The composite components generally comprise a base metal having a ceramic
material
embedded therein. The composite components exhibit improved resistance to wear
and/or impact and, therefore, have a longer usable life or higher impact
resistance than
components formed of the base metal or ceramic material alone. Composite
components may be used to improve a usable life of virtually any wear part
and/or to
improve protection against ballistic or other impacts. While in some examples,
ceramic material may be distributed uniformly throughout a component, in other
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examples, ceramic material may be distributed non-uniformly throughout all or
part of
a composite component.
[0008] In one example, a composite component may be formed by placing one or
more ceramic cores in a mold and introducing molten base metal into the mold,
such
that the molten base metal encapsulates the one or more ceramic cores to form
the
composite component. The ceramic cores may be configured as porous ceramic
cores
made of ceramic particles held together with an adhesive. The base metal, when
introduced into the mold, substantially permeates the porous ceramic core.
Composite
materials formed using this technique may be used for a variety of
applications
including, for example, as ballistic resistant armor for military vehicles, as
a ground
engaging tool, or as a wear surface to resist sliding abrasion.
[0009] In another example, a composite component may be formed by introducing
loose ceramic particles into a mold with a molten base metal. The loose
ceramic
particles may be introduced into the mold prior to or contemporaneously with
the base
metal. In some examples, the loose ceramic particles may be held in place in a
desired
location in the mold by a retaining structure that is permeable by the molten
metal.
The retaining structure may comprise, for example, a metal mesh, a ceramic
mesh, a
fabric, or other suitable structure that can retain the particles at a desired
location in
the mold during the casting process. A portion of the retaining structure may
be
defined by a wall of the mold. In other examples, the loose ceramic particles
may be
unconstrained and may simply be poured into the mold prior to or
contemporaneously
with the molten metal. In that case, the size, shape, amount, and materials of
ceramic
particles used may be chosen based on the desired composite material
properties and
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the desired location and uniformity of the loose ceramic particles in the
composite
component. The flow rate and density, temperature, and turbulence of the
molten
metal, as well as the introduction rate, density, and temperature of the
ceramic
particles may also be chosen to achieve the desired composite material
properties and
the desired location and uniformity of the loose ceramic particles in the
composite
component.
[0010]
In yet another example, a composite component may be formed by applying a
ceramic material to a predetermined location within a mold cavity to create a
ceramic
film. The ceramic material may be applied to the mold cavity by coating all or
part of
the mold cavity with adhesive and ceramic material. The adhesive and ceramic
material may be applied concurrently (e.g., as a slurry or mixture of ceramic
and
adhesive) or sequentially (e.g., by applying the adhesive first and then
applying the
ceramic material). The adhesive and/or ceramic material may be applied by, for
example, brushing them onto the mold cavity, spraying them onto the mold
cavity,
and/or sifting them onto the mold cavity. One or more layers of ceramic film
may be
applied to the mold cavity using any of the techniques described herein.
Molten base
metal may then be introduced into the mold cavity. The molten base metal may
partially, substantially, or completely permeate the ceramic film, and may
encapsulate
the ceramic material. In some examples, the ceramic material comprises ceramic
particles and the molten base metal substantially permeates interstitial
spaces between
the ceramic particles.
[0011]
In summary, the distribution or location of the ceramic materials within the
composite components described above may be manipulated to improve the wear or
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impact characteristics described above. Moreover, a variety of different
metals may
be used as a base metal for any or all of the embodiments and techniques
described
herein. As one example, the base metal may comprise a steel alloy, such as
FeMnAl.
As used herein, the term "steel" includes alloys of iron and carbon, which may
or may
not include other constituents such as, for example, manganese, aluminum,
chromium,
nickel, molybdenum, copper, tungsten, cobalt, and/or silicon. As used herein,
the
term FeMnAl includes any alloy including iron, manganese, and aluminum in any
amounts greater than impurity levels. The techniques described herein may be
used
singly or in combination, depending on the desired characteristics of the
composite
components. The techniques to control the distribution or location of the
ceramic
materials will be discussed further below in the Detailed Description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012]
The Detailed Description is set forth with reference to the accompanying
figures. In the figures, the left-most digit(s) of a reference number
identifies the figure
in which the reference number first appears. The use of the same reference
numbers
in different figures indicates similar or identical items.
[0013]
FIG. 1 is a schematic diagram of a vehicle having an example composite
ballistic armor comprising ceramic material and a base metal.
[0014]
FIGS. 2A, 2B, and 2C are schematic diagrams of example composite
materials having three different embodiments of ceramic cores encapsulated in
a base
metal.
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[0015] FIGS. 3A and 3B are schematic diagrams of a sand mold and an investment
casting mold, respectively, usable to form example composite components using
ceramic cores.
[0016]
FIG. 4 is a flow diagram illustrating an example process of casting a
composite component having one or more ceramic cores encapsulated in a base
metal.
[0017]
FIG. 5 is a schematic diagram of a casting mold that includes a retaining
structure for loose ceramic particles.
[0018]
FIGS. 6A, 6B, and 6C are schematic diagrams of composite components
formed by a ceramic-metal casting process.
[0019] FIG. 7 is a schematic diagram of another casting mold that includes
a
retaining structure for loose ceramic particles.
[0020]
FIG. 8 is a flow diagram illustrating an example process of casting a
composite component having one or more ceramic particles encapsulated in a
base
metal.
[0021] FIGS. 9A and 9B are schematic diagrams of a casting mold in
different
stages of a casting process for a composite component.
[0022]
FIG. 10 is a flow diagram illustrating an example process of casting a
composite component by adding ceramic particles based on processing conditions
for
the composite component.
[0023] FIG. 11 is a schematic diagram of an example mold for creating a
cast part
incorporating ceramics in predetermined locations.
[0024]
FIG. 12 is a schematic diagram illustrating an example technique of spray-
coating a mold with ceramic material in predetermined locations.
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[0025]
FIG. 13 is a schematic diagram illustrating an example technique of sift-
coating a mold with ceramic material in predetermined locations.
[0026]
FIG. 14 is a schematic diagram illustrating an example technique of brush-
coating a mold with ceramic material in predetermined locations.
[0027] FIG. 15 is a flow diagram illustrating an example method of
producing a
composite component by coating a mold with ceramic material.
DETAILED DESCRIPTION
Overview
[0028]
As noted above, manufacturing of composite components is often difficult
due to the varying material properties of the materials from which the
composite
component is made. This application describes composite components comprising
ceramics and metal or metal alloy(s) that, together, exhibit improved
resistance to
wear, friction, and/or impact compared with components formed of ceramic or
metal
alone. This application also describes various techniques for manufacturing
such
composite components. By way of example and not limitation, the composite
components described herein may be used in the fields of excavation,
manufacturing,
metallurgy, milling, material handling, transportation, construction, military
applications, and the like.
[0029]
In general, composite components as described in this application include a
base metal and one or more ceramic materials. This application describes
techniques
for casting such composite components in sand and/or investment casting molds.
In
some embodiments, the ceramic materials are embedded in the base metal in the
form
of ceramic inserts or cores that are encapsulated within the base metal. In
other
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embodiments, the ceramic materials may comprise loose particles or grains of
ceramic
material placed in a mold prior to or contemporaneously with introduction of a
molten
metal or metal alloy. In yet another embodiment, the ceramic material may be
coated
or coupled to portions of the mold prior to introducing the molten metal or
metal
alloys into the mold. Composite components formed using the techniques
described
herein can be said to have the ceramic material distributed non-uniformly, in
so far as
the ceramic material is not evenly distributed throughout the entire
component.
Rather, the ceramic material in the embodiments described herein is localized
at one
or more predetermined locations of the part. The techniques described herein
may be
used singly or in combination, depending on the desired characteristics of the
composite components.
[0030]
The embodiments described herein employ carbon steel or an alloy of steel,
as the base metal. However, in other embodiments, other metals may be used
such as,
for example, iron, aluminum, manganese, stainless steel, copper, nickel,
alloys of any
of these, or the like. In one specific example, FeMnAl alloy may be used as a
base
metal for a composite material. In another specific example, high-chrome iron
(or
white iron) may be used as a base metal for a composite material.
[0031]
Also, while the embodiments described herein employ alumina and/or
zirconia as the ceramic material, other ceramic materials may also be used
such as, for
example, tungsten carbide, titanium carbide, zirconia-toughened alumina (ZTA),
partially stabilized zirconia (PSZ) ceramic, silicon carbide, silicon oxides,
aluminum
oxides with carbides, titanium oxide, brown fused alumina, combinations of any
of
these, or the like. Moreover, while the embodiments discussed herein describe
using
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relatively small particles of ceramic materials (e.g., having a particles size
in the range
of about 0.03 inches to about 0.22 inches, about 0.7 mm to about 5.5 mm), the
ceramic
materials could alternatively be provided in other sizes (e.g., larger or
smaller
particles) or forms (e.g., precast unitary cores as opposed to cores formed of
small
particles or as loose particles). In some examples, using smaller particles
may help to
minimize stresses and cracking due to differences in thermal expansion between
the
base metal and the ceramic particles.
[0032]
In one embodiment, the ceramic materials comprise ceramic particles made
of alumina and zirconia. The relative content of alumina and zirconia of the
ceramic
material may vary depending on the desired toughness, hardness, and thermal
expansion characteristics of the composite component. In general, increasing
an
amount of alumina will increase a hardness of the composite component, while
increasing an amount of zirconia will increase the toughness. In addition,
zirconia has
a coefficient of thermal expansion that closely matches that of iron and steel
and,
therefore, minimizes internal stresses and cracking of the composite
components.
These ceramic grains may be manufactured by any known technique, such as by
electrofusion, sintering, flame spraying, or by any other process allowing the
two
constituents (alumina and zirconia) to fuse.
[0033]
These and other aspects of the composite materials and components will be
described in greater detail below with reference to several illustrative
embodiments.
Example Methods of Forming Composite Components Using Ceramic Cores
[0034]
This section describes an example in which a composite component may be
formed by placing one or more ceramic cores in a mold and introducing molten
base
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metal into the mold, such that the molten base metal encapsulates the one or
more
ceramic cores to form the composite component. In some implementations, the
ceramic cores may be configured as porous ceramic cores made of ceramic
particles
held together with an adhesive, while in other implementations the cores may
comprise pre-cast porous cores. The base metal, when introduced into the mold,
substantially permeates the porous ceramic cores. Composite materials formed
using
this technique may be used for a variety of applications including, for
example, as
ballistic resistant armor for military vehicles, as a ground engaging tool, or
as a wear
surface to resist sliding abrasion. These and numerous other composite
components
can be formed according to the techniques described in this section.
[0035]
FIG. 1 is a schematic diagram of a vehicle 100 having an example
composite ballistic armor, an enlarged detail view of which is shown at 102.
Metal/ceramic materials are well suited to ballistic-resistant applications
due to the
characteristics of the materials. For example, metals typically provide a
relatively
high strength-to-weight ratio and a high toughness, while ceramics have a
relatively
high hardness. Additionally, because the crack propagation speed of ceramics
is
below the speed of a ballistic projectile, ceramic materials provide extremely
strong
defense to ballistic impacts.
[0036]
As shown in FIG. 1, the composite ballistic armor 102 comprises a sheet of
composite material having one or more porous ceramic cores 104 encapsulated in
a
base metal 106. As used herein a "sheet" means a portion of something that is
thin in
comparison to its length and breadth. A sheet may have any desired contour and
is
not limited to being planar. The porous ceramic cores 104 may be formed in a
variety
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of ways. In one example, packed-particle porous ceramic cores 104a may
comprise
ceramic particles held together with an adhesive in a desired shape and size.
In
another example, precast porous ceramic cores 104b may comprise a ceramic
lattice
or mesh-like structure formed in a desired shape and size. Regardless of the
type of
porous ceramic cores used, the porous ceramic cores 104 are configured such
that the
base metal 106 is able to substantially permeate the porous ceramic core 104
during
the casting process. In the case of porous ceramic cores 104a formed from
ceramic
particles, during the casting process the base metal 106 flows into and fills
the
interstitial spaces between the particles during the casting process.
[0037] As noted above, the base metal may comprise a variety of different
metals.
However, in the ballistic armor example of FIG. 1, the base metal comprises a
steel
alloy, such as FeMnAl, an aluminum alloy, or other metals having a relatively
high
strength-to-weight ratio, toughness, and/or hardness.
[0038]
FIGS. 2A-2C illustrate three embodiments of ceramic cores that may be
used to form composite components, such as the composite ballistic armor of
FIG. 1.
In all three embodiments, a sheet of composite material 200 comprises a
plurality of
strata, including an outer stratum 202 of solid base metal, an inner stratum
204 of
solid base metal, and a composite stratum 206, interposed between the outer
stratum
and the inner stratum. The composite stratum 206 comprises one or more porous
ceramic cores encapsulated in and substantially permeated by base metal.
[0039]
In the embodiment of FIG. 2A, the composite stratum 206 is composed of a
single ceramic core 208a, which is thinner than, but is substantially
coextensive with
the sheet of composite material 200. In this embodiment, the ceramic core 208a
is
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shaped to match the contours of a mold used to cast the sheet 200 of the
composite
component. The ceramic core 208a may be formed in a variety of known
techniques,
such as packing ceramic particles into a core mold and holding the ceramic
particles
together with an adhesive. Once the ceramic core 208a is set, it may be
removed from
the core mold and placed in a mold used for casting the composite component.
[0040]
In the embodiments of FIG. 2B and FIG. 2C, the composite stratum 206 is
composed of a plurality of porous ceramic cores 208b and 208c arranged to
provide a
substantially uniform, continuous thickness of porous ceramic cores that
extends
substantially coextensively with the sheet of composite material. In the
embodiment
of FIG. 2B, the porous ceramic cores 208b have a generally rhomboidal cross-
section.
The porous ceramic cores 208b of this embodiment are arranged in an
overlapping
fashion, as shown in FIG. 2B, such that a thickness of the composite stratum
206 is
substantially uniform along a length of the sheet of composite material 200.
In the
embodiment of FIG. 2C, the porous ceramic cores 208c have a tongue-and-groove
cross-section. The porous ceramic cores 208c of this embodiment are arranged
with a
tongue of one porous ceramic core 208c received in a groove of an adjacent
porous
ceramic core 208c, as shown in FIG. 2C, such that a thickness of the composite
stratum 206 is substantially uniform along a length of the sheet of composite
material
200.
[0041] The sheet of composite material 200 may have any desired thickness.
Moreover,
the relative thicknesses of the strata 202, 204, and 206 may vary depending on
the
application. However, when used for a ballistic armor application, such as
that shown in
FIG. 1, the sheet of composite material may have a thickness of at least about
1 inch
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and at most about 4 inches. Generally, in such ballistic armor applications,
the outer
stratum may be thinner than each of the inner stratum and the composite
stratum. For
example, the outer stratum 202 may have a thickness of at least about 0.125
inches
and at most about 0.5 inches, the inner stratum 204 may have a thickness of at
least
about 0.5 inches and at most about 1.5 inches, and the composite stratum 206
may
have a thickness of at least about 0.5 inch and at most about 2 inches. In one
specific
example, the outer stratum 202 may have a thickness of about 0.25 inches, the
inner
stratum 204 may have a thickness of about 0.75 inches, and the composite
stratum 206
may have a thickness of at least about 0.75 inch and at most about 1 inch.
[0042] In some embodiments, the base metal used for the outer stratum 202,
the
inner stratum 204, and the composite stratum 206 may be the same. However, in
other embodiments, different alloys and/or different metals may be used for
one or
more of the strata. For example, a harder alloy may be used for the outer
stratum 202
to provide deflect impacts, while a softer yet tougher alloy may be used for
the inner
stratum 204 and/or the composite stratum 206 to absorb energy of incoming
projectiles and to minimize cracking of the composite stratum 206. Whether
formed
using a single base metal or multiple different base metals or alloys, the
outer stratum 202,
inner stratum 204, and the composite stratum 206 may be formed integrally as a
single
casting.
[0043] In one specific example, the outer stratum 202, inner stratum 204,
and the
composite stratum 206 comprise FeMnAl as the base metal. In other specific
example, the composite stratum 206 comprises FeMnAl as the base metal, while
the
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outer stratum 202 and/or the inner stratum 204 comprise a steel alloy other
than
FeMnAl.
[0044]
The composite ballistic armor 102 of FIG. 1 and other composite
components may be cast using sand casting techniques or investment casting
techniques. FIG. 3A is a schematic diagram illustrating a simplified example
sand
casting process usable to cast composite components, such as the composite
ballistic
armor of FIG. 1. As shown in FIG. 3A, a casting mold 300 is formed in a shape
configured to produce a desired composite component. The casting mold 300
includes a sand container 302 and a sand mold 304 that may be formed or
arranged to
facilitate the casting of a composite component of various geometries. The
mold
geometries shown in FIG. 3A are for component with a simple rectangular cross
section. However, in other embodiments molds may be configured for components
of
any desired shape, size, and configuration. A pressing a riser 306 is provided
to press
down against the sand mold 304 to form a top surface of the composite
component.
[0045] FIG. 3B is a schematic diagram illustrating a simplified example
investment
casting process usable to cast composite components, such as the composite
ballistic
armor of FIG. 1. As shown in FIG. 3B, an investment casting mold 308 is formed
of a
refractory material in a shape configured to produce a desired composite
component.
[0046]
In both FIGS. 3A and 3B, molten base metal 106 is shown being poured
into the casting mold 300,308 and permeating a porous ceramic core 104 to form
the
composite component.
[0047]
FIG. 4 is a flow diagram illustrating a process 400 that may, but need not
necessarily, be used to cast composite components, such as the ballistic armor
of
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FIG. 1. However, the process 400 is usable to make a variety of other
composite
components including, without limitation, those listed elsewhere in this
application.
The process 400 includes, at 402, preheating one or more ceramic cores in a
sand or
investment mold and, at 404, placing the ceramic cores in the mold. In the
case of an
investment mold, placing a ceramic core in an investment mold may include
forming
the investment mold around the ceramic core. Depending on the process, the
ceramic
cores may be preheated prior to or after being placed in the mold. That is,
the ceramic
cores may be preheated and then placed in the mold, or (at least in the case
of
investment casting) may be placed in the mold and then preheated in situ. The
ceramic cores may comprise porous ceramic cores, such as the packed-particle
porous
ceramic cores 104a and/or precast porous ceramic cores 104b shown in FIG. 1.At
406,
one or more molten base metals may be introduced into the mold to partially,
substantially, or completely encapsulate the ceramic material. In one example,
the
molten base metal may comprise a steel alloy, such as FeMnAl. In other
embodiments, multiple different molten base metals may be introduced into the
mold
at different locations and/or times. For example, a first base metal may be
poured at a
first time, and a second, different base metal may be poured at a second,
later time
during the same casting process. As another example, two different base metals
may
be introduced into the mold at different locations of the mold (e.g., using
different
sprues).
[0048]
At 408, the cast composite component may be subjected to one or more heat
treatments or post processing operations, such as machining, heat treating
(e.g.,
quenching, annealing, tempering, austempering, cryogenic hardening, etc.),
polishing,
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or the like. Additional details of various heat treatments and post processing
operations are described further below in the section entitled "Illustrative
Manufacturing Processes." In some implementations, different heat treatment
operations may be applied to different sides of a composite component. For
example,
a first heat treatment operation may be applied to a first side of a ballistic-
resistant
part (e.g., to harden the first side) and a second heat treatment operation
may be
applied to a second side of the ballistic-resistant part (e.g., to relieve
stresses or
increase a ductility of the second side).
Example Methods of Forming Composite Components Using Loose Particles
[0049] This section describes examples, in which a composite component may
be
formed by introducing loose ceramic particles into a mold with a molten base
metal.
The loose ceramic particles may be introduced into the mold prior to or
contemporaneously with the base metal. In some examples, the loose ceramic
particles may be held in place in a desired location in the mold by a
retaining structure
that is permeable by the molten metal. The retaining structure may comprise,
for
example, a metal mesh, a ceramic mesh, a fabric, or other suitable structure
that can
retain the particles at a desired location in the mold during the casting
process. A
portion of the retaining structure may be defined by a wall of the mold.
[0050]
In other examples, the loose ceramic particles may be unconstrained and
may simply be poured into the mold prior to or contemporaneously with the
molten
metal. In that case, the size, shape, amount, and materials of ceramic
particles used
may be chosen based on the desired composite material properties and the
desired
location and uniformity of the loose ceramic particles in the composite
component.
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The flow rate and density, temperature, and turbulence of the molten metal, as
well as
the introduction rate, density, and temperature of the ceramic particles may
also be
chosen to achieve the desired composite material properties and the desired
location
and uniformity of the loose ceramic particles in the composite component.
[0051] FIG. 5 is a diagram of a casting mold 500 for casting composite
components (i.e., metal-ceramic components) that includes a retaining
structure 502 to
secure loose ceramic particles 504 during the casting process. The casting
mold 500
includes a sand container 506 and a sand mold 508 that may be formed or
arranged to
facilitate the casting of a metal ceramic part of various geometries. By way
of
example and not limitation, FIG. 5 shows the sand mold 508 formed to cast a
square
or rectangular composite component with a combination of substantially
horizontal
and substantially vertical surfaces. The retaining structure 502 is shown to
be in
contact with one of the substantially horizontal surfaces molded into the sand
508 in
FIG. 5. The top surface of the composite component formed by casting mold 500
is
formed by pressing a riser 510 down against the sand mold 508 to form the
molten
metal 512 into a desired shape for the composite component. The molten metal
512 is
shown being poured into the casting mold 500 in FIG. 5. In the illustrated
example, a
single retaining structure 502 is centered on the horizontal surface of the
casting mold
500. However, more than one retaining structure 502 may be placed in the sand
mold
508 during the casting process. Moreover, the size, shape, and location of the
retaining structure may be configured based on the requirements of the
composite
component to be cast. Additional embodiments that may use more than one
retaining
structure will be described in the discussion of FIGS. 6B and 6C.
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[0052]
The retaining structure 502 secures the loose ceramic particles 504 to a
desired location within the casting mold 500 such that the composite component
produced by the casting mold 500 has the ceramic particles localized in a
desired
location based on the intended use of the composite component. For example,
the
retaining structure 502 may hold the ceramic particles in place at location of
the
composite component that is anticipated to receive higher abrasion to provide
a harder
wear surface. The retaining structure 502 may comprise any structure that is
permeable to molten metal and impermeable to the loose ceramic particles 504.
For
example, the retaining structure 502 may be arranged as a mesh structure made
of
metal wire or fabric that can maintain their structural integrity when exposed
to the
molten metal 512. Also, in one embodiment, the mesh structure may only need to
maintain structural integrity for a small period of time when exposed to the
molten
metal and may not need to maintain perfect structural integrity for the entire
casting
process. Additionally, the retaining structure 502 may melt or dissolve during
the
casting process but resist the molten metal long enough such that the loose
ceramic
particles 508 are secured in the desired location prior to melting or
dissolving of the
retaining structure 502. Examples retaining structures include, without
limitation,
steel or other metal meshes or wire frames, high temperature fabrics (e.g.,
those made
of Teflon , Kevlar , or the like), or ceramic meshes or frames.
[0053] In one embodiment, as illustrated by 514, the retaining structure
502 may
have ceramic particles 504 completely enclosed within the retaining structure
502.
The retaining structure may be placed or secured to any surface within the
casting
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mold 500. Additionally, more than one type of ceramic material may be included
within the same retaining structure 502.
[0054]
In another embodiment, as illustrated by 516, the retaining structure 502 is
in contact with or secured to a surface 518 of the casting mold with the loose
ceramic
particles 504 being secured between the retaining structure 502 and the
casting mold
surface 518.
[0055]
FIGS. 6A-6C illustrate additional embodiments related to the placement of
the retaining structure 502 in the casting mold 500 to provide different
configurations
of the composite component. FIG. 6A provides a representative example of a
composite component 600 produced by the casting mold 500 embodiment
illustrated
in FIG. 5. The composite component 600 includes a metal portion 602 and a
ceramic-
metal portion 604. The location of the ceramic-metal portion 604 was imparted
to the
composite component 600 by placing the retaining structure(s) 502 at a
corresponding
location(s) within the casting mold 500. Although FIG. 6A shows that the
ceramic-
metal portion 502 is centered on the bottom surface of the composite component
600,
the ceramic-metal portion may be positioned anywhere along any surface of the
composite component 600. Further, the ceramic-metal portion 602 may have the
ceramic particles distributed in a non-uniform manner, such that the non-
uniformity of
the ceramic material within the ceramic-metal portion 602 is greater than or
equal to
10%. Put differently, in this example, the ceramic-metal portion 602
constitutes at
most 10% of the total volume of the composite component.
[0056]
FIG. 6B is an illustration of a composite component 606 that includes a
metal portion 608 and a ceramic-metal portion 610 that spans the entire bottom
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surface of the composite component 608. Also, the ceramic-metal portion 610
may
include a portion of the side surfaces of composite component 608.
[0057]
FIG. 6C illustrates another embodiment of the composite component 612
that includes a metal portion 614 and ceramic-metal portions 616, 617, and
618. This
illustrated arrangement may be produced by using multiple retaining structures
502
during the casting process. The ceramic-metal portions may be arranged
according to
the intended use of the composite component. For example, the coverage of the
ceramic-metal portions may be configured to account for wear along the bottom
surface. Also, the depth of the ceramic-metal portion into the composite
component
612 may be varied based on the intended use.
[0058]
FIG. 7 illustrates another casting mold 700 that incorporates a sand mold
design 702 that provides a reservoir or indentation for the loose ceramic
particles 704
that are secured in place by a retaining structure 706 placed over the
reservoir. The
depth and size of the reservoir may vary according to the intended use of the
composite component being manufactured. Also, several reservoirs may be
incorporated into the sand mold design and they may vary in shape or
orientation
dependent upon, again, the intended use of the composite component. In another
embodiment (not illustrated), the reservoirs may be incorporated into the
vertical walls
of the sand mold or any other surface of the sand mold and secured in place by
a
retaining structure.
[0059] FIG. 8 is a flow diagram of an example method 800 of forming a
composite
component 600. The method 800 is described with reference to the elements of
FIGS.
5-7 for convenience. However, the method 800 need not, necessarily, be
performed
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using the example molds or to produce the example composite components
described
with reference to those figures. At 802, a plurality of loose ceramic
particles 504 are
secured in a casting mold 500 using a retaining structure 502. In one
embodiment, the
casting mold is a sand mold 508 that may be arranged to form the shape of the
composite component 600. The retaining structure 502 may envelop all of the
ceramic particles 504 as shown by 514, or the ceramic particles may be secured
between the retaining structure 502 and the sand mold 508. In an alternative
embodiment, more than one retaining structure may be used in the casting
process.
For example, three retaining structures may be used to form the composite
component
606, as illustrated in FIG. 6B.
[0060]
At 804, molten metal 512 is poured into the casting mold 500. The molten
metal 512 permeates the retaining structure 502 and is diffused into the
interstitial
spaces between the loose ceramic particles 504.
[0061]
At 806, the solid composite component 600 is formed when the molten
metal 512 solidifies in the casting mold as the temperature of the molten
metal 512
decreases.
[0062]
FIGS. 9A and 9B are an illustrative example of adding loose ceramic
materials to a casting mold 900 when the molten metal 512 is being poured into
the
sand mold 902. FIG. 9A illustrates a time interval at the beginning of the
process
prior to introducing the loose ceramic materials 904 into the molten metal
512. In this
embodiment, the molten metal 512 is being poured into the sand mold 902. The
loose
ceramic particles may be added to the molten metal 512 as indicated by the
arrows
pointing from the loose ceramic particles 904 to the molten metal 512. The
timing
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and placement of the loose ceramic particles will be discussed in greater
detail in the
discussion of FIG. 10.
[0063]
FIG. 9B illustrates the casting mold 700 in FIG. 9A near the end of the
pouring process that was started in FIG. 9A. The loose ceramic particles 904
have
been introduced into the molten metal 512 and reside in a desired location in
the sand
mold 902. In this embodiment, the density of the loose ceramic particles 904
is
greater than the density of the molten metal 512 which enables the loose
ceramic
particles 904 to reside in a desired location of the sand mold 902 as the
molten metal
512 is being poured. However, in another embodiment, the density of the loose
ceramic particles may be less than the density of the molten metal 512, such
that they
float in the molten metal 512.
[0064]
FIG. 10 is a method 1000 pertaining to optimizing location of loose
particles 904 during the pouring of molten metal 512 into the sand mold 902
illustrated in FIGS. 9A and 9B. At 1002, molten metal 512 is poured into the
casting
mold 900.
[0065]
At 1004, loose ceramic particles 904 are added to the molten metal 512 at a
time determined based in part on a flow rate and a density of the molten metal
and a
desired location of the ceramic particles in the composite component 600. The
addition of the loose particles may also be based in part on a desired
uniformity/non-
uniformity or a desired density of the loose ceramic particles in the
composite
component 600. Other factors may also be used to determine when and how many
loose particles are added to the sand mold 902. For example, the factors may
include
a temperature of the molten metal, turbulence of the molten metal, a
temperature of
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the loose ceramic particles, and a density or a size of the loose ceramic
particles. In
one embodiment, the loose ceramic particles may be pre-heated to a desired
temperature prior to being introduced to the molten metal. Moreover, more than
one
amount or group of the same or different loose ceramic particles may be added
during
this process. For example, a first amount of loose ceramic particles may be
introduced
into the molten metal at a first time (e.g., t=15s) and then a second amount
of loose
ceramic particles may be introduced at a second time (e.g., t=25s). Not only
may the
amounts vary, but different types of particles may added at different times
and at
different locations in the sand mold 902. Again, these variables may be
determined by
the intended use of the composite component.
[0066]
At 1006, the composite component 600 is formed by cooling the molten
metal until it solidifies.
[0067]
The molten metal introduced into the mold in any of the methods described
in this section may include iron, carbon steel, or an alloy of iron or steel,
as the metal
alloy. However, in other embodiments, other metals may be used, such as
aluminum,
manganese, stainless steel, copper, nickel, alloys of any of these, or the
like (e.g.,
FeMnA1). Furthermore, in some embodiments, multiple different metals or alloys
may be used.
[0068]
Following the formation of the composite component 600 according to any
of the methods described in this section, the composite component 600 may be
subjected
to one or more heat treatments or post processing operations, such as
machining, heat
treating (e.g., quenching, annealing, tempering, austempering, cryogenic
hardening,
etc.), polishing, or the like. Additional details of various heat treatments
and post
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processing operations are described further below in the section entitled
"Illustrative
Manufacturing Processes."
Example Methods of Forming Composite Components by Coating a Mold
[0069]
This section describes examples, in which a composite component may be
formed by applying a ceramic material to a predetermined location within a
mold
cavity to create a ceramic film. The ceramic material may be applied to the
mold
cavity by coating all or part of the mold cavity with adhesive and ceramic
material.
The adhesive and ceramic material may be applied concurrently (e.g., as a
slurry or
mixture of ceramic and adhesive) or sequentially (e.g., by applying the
adhesive first
and then applying the ceramic material). The adhesive and/or ceramic material
may
be applied by, for example, brushing them onto the mold cavity, spraying them
onto
the mold cavity, and/or sifting them onto the mold cavity. One or more layers
of
ceramic film may be applied to the mold cavity using any of the techniques
described
herein. Molten base metal may then be introduced into the mold cavity. The
molten
base metal may partially, substantially, or completely permeate the ceramic
film, and
may encapsulate the ceramic material. In some examples, the ceramic material
comprises ceramic particles and the molten base metal substantially permeates
interstitial spaces between the ceramic particles.
[0070]
FIG. 11 is an illustration of an example mold 1100 for creating a cast part
incorporating ceramics in predetermined locations. The mold may be either a
sand
casting mold or an investment casting mold that is used to create cast parts.
The mold
cavity 1102 is formed within the mold. A refractory wash 1104 is used to wash
the
mold cavity 1102. While the cast part may be formed without a refractory wash
1104,
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in most case, the use of a refractory wash 1104 is desirable. A refractory
wash 1104 is
used to create a film that provides for a smoother finish on the cast part.
The
refractory wash 1104 also serves to eliminate sand burn-in in a sand casting
and
provides a barrier layer which is not penetrable by the molten base metal thus
preventing the molten base metal from permeating the mold itself The
refractory
wash may comprise a zircon wash and/or an alumina wash.
[0071]
Ceramic material 1108 is applied in predetermined locations prior to
pouring in a molten metal 1110. Depending on the particular needs of an
application
and the precision desired, the ceramic material 1108 may be simply poured on
the
predetermined location. In another embodiment, the ceramic material 1108 may
be
held in place by a high temperature adhesive 1106 that is applied prior to the
application of the ceramic material 1108 and after the application of the
refractory
wash 1104. As discussed in the previous section, the ceramic material 1108 may
also
be held in place by a high temperature mesh or a coated fabric instead of the
high
temperature adhesive or in addition to the high temperature adhesive. In yet
another
embodiment, the ceramic material 1108 may be mixed with a high temperature
adhesive and applied in a sludge or slurry mixture form. In either embodiment
using
an adhesive, the ceramic material stays in place and the high temperature
adhesive
disintegrates once the molten metal 1110 is poured into the mold cavity 1102.
[0072] The ceramic material 1108 may be applied in a variety of ways. For
instance, the ceramic material 1108 may be sprayed on, brushed on, sifted on,
simply
poured in, or applied using a combination of these processes. Prior to pouring
in the
molten metal, excess ceramic material 108 that may have inadvertently been
applied
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to areas other than the predetermined locations may be removed. This may be
accomplished by vacuuming out, brushing off, or blowing off the excess ceramic
material 1108. Additionally or alternatively, ceramic material may be removed
from
unwanted areas by masking the areas prior to applying the ceramic material
1108.
The masking is further discussed with reference to FIG. 12 below. As stated
earlier,
the ceramic material may include alumina and/or zirconia as well as other
materials
such as tungsten carbide, titanium carbide and zirconia-toughened alumina. The
molten metal may include iron, steel, manganese, stainless steel, copper,
nickel or any
combination or alloy of any of these (e.g., FeMnA1).
[0073] In some instances, multiple ceramic film layers may be applied to
build up
additional thickness of ceramic material. Whether or not multiple layers are
used is
determined by the desired thickness of the ceramic wear surface. Additional
thickness
in ceramic film layers may be accomplished by applying several layers of
ceramic
material in multiple applications to incrementally increase the surface
thickness. The
ceramic material used in one or more of the multiple layers may be the same
as, or
different from, that used in the other layers. Additionally, a ceramic core,
such as
those shown in FIGS. 1-3 may be placed in predetermined locations to increase
the
thickness in particularly high wear locations. The ceramic core may be held in
place
by adhesive so that no movement occurs when the molten metal in poured into
the
mold cavity 102.
[0074]
As the molten metal 1110 is poured into the mold cavity 1102, the molten
metal 1110 permeates the ceramic material 1108, i.e., the molten metal 1110
permeates the interstitial spaces between the ceramic particles. However, the
molten
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metal 1110 does not permeate the refractory wash 1104. Consequently, as the
molten
metal 1110 cools, a cast part is formed with a ceramic particle wear surface
formed
within the cast part at predetermined locations. The predetermined locations
are
typically the portion of the cast part that will be exposed to the most wear,
whether
from impact, abrasion, or other wear.
[0075]
FIG. 12 is an illustration of a mold 1200 for creating a cast part
incorporating ceramics in predetermined locations. This mold 1200 is similar
to that
described in FIG. 11 above. The mold 1200 includes a mold cavity 1202. In this
embodiment, a mask 1204 is applied to portions of the mold cavity 1202 in
which
ceramic material is not desired. The mask 1204 may be any type of material
that
prevents the ceramic material 1208 from adhering to the material or makes the
material easy to blow off, scrape off or brush off For instance, the mask 1204
may be
a removable tape with a sticky surface on one or both sides. The mask 1204 is
applied
to the areas other than the predetermined locations and held in place by one
side of the
adhesive tape. After the ceramic material 1208 is applied, the mask 1204 is
removed
prior to pouring in a molten metal, thus removing any oversprayed ceramic
material
1208. A mask 1204 provides for easy removal of the excess ceramic material
that is
located in areas where ceramic material is not desired.
[0076]
A refractory wash 1206 is applied to a predetermined location and the
ceramic material 1208 is applied to the predetermined location over the
refractory
wash 1206 using a sprayer 1210. The refractory wash 1206 may also be applied
to the
entire mold cavity 1202 before both the mask 1204 and the ceramic material
1208 are
applied. Since the refractory wash 1206 helps to provide a smoother finish to
the cast
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part and prevents sand burn-in in sand casting, it may be desirable to apply
the
refractory to the entire mold cavity 1202 and not just the predetermined
locations. In
this embodiment, ceramic material is applied concurrently with an adhesive by
the
sprayer 1210. However, in other embodiments, the adhesive may be applied first
to
the predetermined locations and the ceramic material may be applied
subsequently by
pouring or sifting the ceramic material onto the locations coated with the
adhesive.
While a hand sprayer is shown, the spraying mechanism may be part of a
manufacturing operation and be automated.
[0077]
After the excess ceramic material 1208 is removed from the areas other than
the predetermined locations, the molten metal in poured into the mold cavity
1202 and
allowed to cool to form a cast part. This embodiment also allows the cast part
to be
formed in thin sizes that are smaller than those normally able to be cast with
a ceramic
wear surface.
[0078]
FIG. 13 illustrates another embodiment of a mold 1300 for creating a cast
part incorporating ceramics in predetermined locations. This mold 1300 is
similar to
that described in FIG. 12 above except for the means for applying the ceramic
material. The mold 1300 includes a mold cavity 1302. A mask 1304 is applied to
portions of the mold cavity 1302 in which ceramic material is not desired. A
refractory wash 1306 is applied to the mold cavity 1302. Finally, the ceramic
material
1308 is applied to the predetermined locations using a sifter 1310. Again, if
desired,
multiple layers of the ceramic material 1308 may be applied to create a
desired
thickness of ceramic material. In addition to or in lieu of the multiple
layers, a
ceramic core may also be placed in the predetermined locations to increase the
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ceramic wear surface thickness in certain areas. Since a sifter 1310 is not as
precise as
other application methods, the use of the mask 1304 may be more useful for
removing
the excess ceramic material from use of the sifter 1310 prior to pouring in a
molten
metal to form a cast part. After the overspray is removed, the molten metal is
poured
into the mold cavity 1302 and allowed to cool to form a cast part.
[0079]
FIG. 14 is another embodiment of a mold 1400 for creating a cast part
incorporating ceramics in predetermined locations. This mold 1400 is similar
to that
described in FIG. 12 above except for the means for applying the ceramic
material.
The mold 1400 includes a mold cavity 1402. In this embodiment, the ceramic
material 1406 is applied to the predetermined locations using a brush 1408.
The use
of a mask is optional given the more precise application of using a brush
1408. In the
event a mask is used, the mask is applied to portions of the mold cavity 1402
in which
ceramic material is not desired. A refractory wash 1404 is again applied to
the mold
cavity 1402 to improve the finish of the cast part and maintain mold
integrity. Finally,
the ceramic material 1406 is applied to the predetermined locations using a
brush
1408. Again, if desired, multiple layers of the ceramic material 1406 may be
applied
to create a desired thickness of ceramic material. In addition to or in lieu
of the
multiple layers, a ceramic core may be placed in the predetermined locations
to
increase the ceramic wear surface thickness in certain areas. After the excess
ceramic
material 1406 is removed, the molten metal in poured into the mold cavity 1402
and
allowed to cool to form a cast part.
[0080]
FIG. 15 is a flow diagram illustrating a method 1500 of producing a cast
part. At 1502, a mold cavity is provided that is formed to produce the cast
part. The
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mold cavity is washed with a refractory wash to create a film over the mold
cavity at
operation 1504. The refractory wash provides for a smoother finish on the cast
part
and provides a barrier to prevent the molten metal from permeating the mold. A
high
temperature adhesive is applied over the refractory wash to predetermined
locations in
operation 1506. The predetermined locations are selected based on the location
of the
wear surfaces of the cast part. Typically, the ceramic material is applied to
a wear
surface in those areas where the most wear occurs.
[0081]
The ceramic material is applied to the predetermined locations in operation
1508. The ceramic material is penetrable by the molten metal, i.e., the molten
metal
permeates the interstitial spaces between the ceramic particles. The ceramic
material
may be applied in many different ways, including pouring on, spraying on,
brushing
on and sifting on. In addition, the ceramic material and adhesive may be
applied
separately as just described or the ceramic material and adhesive may be mixed
together prior to application such that the mixture in the form of a sludge or
slurry
type of mixture that can be applied to the predetermined locations. The
ceramic
material may be held in place by a high temperature mesh or a coated fabric
instead of
the high temperature adhesive or in addition to the high temperature adhesive.
[0082]
Any excess ceramic material may be removed from undesired locations at
operation 1510. The excess material may be due to overspray or spillage that
is
inadvertently applied outside the predetermined locations. The removal of the
excess
ceramic material may be accomplished by vacuuming off, blowing off, or
brushing off
the excess ceramic material, or by masking the areas prior to applying the
ceramic
material. The mask may be any type of material that prevents the ceramic
particles
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from adhering to the mold or makes the material easy to blow off, vacuum off,
scrape
off or brush off. For instance, the mask may be a removable tape with a sticky
surface
on one or both sides. This would allow the mask to be removed prior to pouring
in a
molten metal, thus removing any oversprayed or overapplied ceramic material.
[0083] In some instances, multiple ceramic film layers are built in
operation 1512.
Whether or not multiple layers are used is determined by the desired thickness
of the
ceramic wear surface. The additional thickness in ceramic film layers may be
accomplished by applying several layers of ceramic material to incrementally
increase
the surface thickness and/or a ceramic core may be placed in the mold cavity
to add
additional thickness.
[0084]
In operation 1514, molten metal is poured into the mold to produce the cast
part. The molten metal permeates the ceramic material layer/layers, but does
not
permeate the refractory wash film. As the molten metal cools, the cast part is
formed
and the ceramic wear surface becomes an integral portion of the cast part.
[0085] The embodiments described in this section allow for the formation of
cast
parts having relatively thin cross-sections ¨ smaller than those normally able
to be cast
with a ceramic wear surface. For instance, this process can be used to cast
parts as
thin as 0.25 inches. In some embodiments, this process can be used to cast
parts
having a thickness of between about 0.25 inches and about 1.5 inches. In
addition,
thicker cast parts are also able to be formed using this embodiment.
Illustrative Manufacturing Processes
[0086]
The composite components described herein can be made by a variety of
manufacturing processes. In one example, the ceramic materials are placed in a
mold
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according to one of the techniques described above. As noted above, the
ceramic
materials may be preheated prior to casting to remove moisture and/or to
elevate the
temperature of the ceramic material to slow solidification of the base metal
during the
casting process for better permeation into the ceramic material. The composite
component may then be formed by injecting molten base metal into molds using
conventional casting techniques. Subsequently, the composite component may be
subjected to one or more post processing operations, such as machining, heat
treating
(e.g., quenching, annealing, tempering, austempering, cryogenic hardening,
etc.),
polishing, or the like. Various heat treatments can implement phase changes in
the
metal of the composite component that allow the wear or impact resistant
characteristics to be varied to account for different uses of the composite
component
part. Heat treatment techniques may also be used to reduce internal stresses
in the
composite components due to different coefficients of thermal expansion of the
base
metal and the ceramic materials, thereby reducing cracking or voids in the
composite
components.
[0087]
Previous attempts to quench metal/ceramic composite materials have been
unsuccessful due to the different characteristics of the metal and ceramic
materials.
However, several processes used separately or in combination may facilitate
quenching of metal/ceramic components.
For example, internal stresses of
metal/ceramic components may be reduced by preheating the ceramic materials
prior
to casting, choosing ceramics and metals having relatively similar
coefficients of
thermal expansion, using relatively smaller ceramic particles, employing a
quench
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with a relatively higher quench temperature, such as austempering, and/or
employing
a quench medium with a relatively lower rate of quench (e.g., air).
[0088]
In one embodiment, the wear and/or impact resistance of a composite
component can be modified by austempering. Generally, austempering refers to
the
isothermal transformation of a ferrous alloy at a temperature below that of
pearlite
formation and above that of martensite formation. Further, the metal may be
cooled to
the austempering temperature fast enough to avoid transformation of austenite
during
cooling. Then the component is held at a constant temperature long enough to
ensure
complete transformation of austenite to bainite. Austenite, martensite,
pearlite, and
bainite are common metallurgical terms that represent the various phases or
crystal
structures in which ferrous alloys may exist. Austenite is a metallic non-
magnetic
allotrope of iron or a solid solution of iron, with an alloying element such
as nickel
that has a face-centered cubic structure. Pearlite is a layered crystal
structure of
cementite and ferrite formed during the cooling of austenite. Martensite is a
constituent formed in steels by rapid quenching of steel that is in the
austenite phase.
It is formed by the breakdown of austenite when the rate of cooling is large
enough to
prevent pearlite forming in the steel. The martensite crystal structure is
generally
known to be a body-centered tetragonal crystal structure. Bainite is produced
when
austenite is transformed at temperatures below the pearlite and martensite
temperature
ranges of ferrous alloys.
[0089]
By way of example and not limitation, austempering may include placing
the composite component in a salt bath that is maintained at a temperature
between
about 500C and about 900C. The temperature is maintained at a substantially
constant
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value during the austempering process to insure complete transformation of the
metal
alloy in the composite component from austenite to bainite. Also, the salt
bath may
include neutral salts that are not reactive with the metal or metal alloys
included in the
composite component.
[0090] In another embodiment, the wear and/or impact resistance of a
composite
component can be modified by air quenching. Air quenching may involve placing
the
composite component in atmospheric conditions and permitting the composite
component to cool over a period of time in order to implement a phase change
in the
metal of the composite component. In other implementations, the composite
component may be subjected to elevated or lowered air temperatures to alter
the
temperature differential between the component and the air. Additionally or
alternatively, air quenching may also include subjecting the component part to
forced
air drafts to implement a different phase change of the metal in the composite
component due changes in heat transfer caused by the forced air drafts.
[0091] In another embodiment, the wear and/or impact resistance of a
composite
component can be modified by oil quenching. Oil quenching may involve placing
the
composite component in an oil bath that is maintained at a constant
temperature. By
way of example and not limitation, the oil bath may be maintained at a
temperature of
at least about 150C. Also, the types of oil may include oils that have a high
flash
point that prevents the oil from catching fire. Additionally, the composite
component
may be placed in additional oil baths following the quenching process to
temper the
metal in the composite component. By way of example and not limitation, the
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tempering process may involve several baths with temperatures ranging from
about
150C to about 650C.
[0092]
In another embodiment, the wear and/or impact resistance of a composite
component can be modified by polymer quenching. Again, the quenching process
may include placing the composite component in a polymer bath in order to
control
the cooling rate of the metal in the composite component. By way of example
and not
limitation, the polymer bath may include a mix of water and glycol polymers at
temperatures ranging from room temperature to about 400C.
[0093]
In another embodiment, the wear and/or impact resistance of a composite
component can be modified by water quenching by placing the composite
component
in a water bath. The temperature of water bath is maintained at a value less
than the
boiling point of water.
[0094]
The heat treatments described above may be used alone or in combination
with each other. For example, an austempering process may be followed by air
quenching or oil quenching/tempering. Additionally, the liquid quenching
techniques
described above may use agitation of the liquid to modify the heat transfer
characteristics of the heat treatments to impart various wear and/or impact
resistant
characteristics to the metal in the composite component.
Conclusion
[0095] Although the disclosure uses language specific to structural
features and/or
methodological acts, the claims are not limited to the specific features or
acts
described. Rather, the specific features and acts are disclosed as
illustrative forms of
implementing the invention. For example, the various embodiments described
herein
leeehayes pllc 509.324.9256
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may be rearranged, modified, and/or combined. As another example, one or more
of
the method acts may be performed in different orders, combined, and/or omitted
entirely, depending on the composite component to be produced.
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