U.S. patent application number 14/551467 was filed with the patent office on 2016-05-26 for atomizing apparatuses, systems, and methods.
The applicant listed for this patent is ATI PROPERTIES, INC.. Invention is credited to Matthew J. Arnold, Anthony Banik.
Application Number | 20160144435 14/551467 |
Document ID | / |
Family ID | 54848887 |
Filed Date | 2016-05-26 |
United States Patent
Application |
20160144435 |
Kind Code |
A1 |
Banik; Anthony ; et
al. |
May 26, 2016 |
ATOMIZING APPARATUSES, SYSTEMS, AND METHODS
Abstract
An atomizing system and method are disclosed. A system can
include a tundish configured to hold a molten material and a nozzle
in fluid communication with the tundish. The nozzle and/or the
tundish can be comprised of a material having a composition that is
substantially similar to the composition of the molten material. An
internal channel can be defined in at least one of the tundish or
the nozzle. Additionally, a pump can be configured to pump a molten
heat transfer medium through the internal channel. A method of
atomizing the molten material can include affecting heat transfer
between the molten material and the tundish and/or the nozzle with
a molten heat transfer medium in at least one internal channel in
the tundish and/or the nozzle. The tundish and/or the nozzle can
comprise a material that is substantially similar to the molten
material.
Inventors: |
Banik; Anthony; (Monroe,
NC) ; Arnold; Matthew J.; (Charlotte, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ATI PROPERTIES, INC. |
Albany |
OR |
US |
|
|
Family ID: |
54848887 |
Appl. No.: |
14/551467 |
Filed: |
November 24, 2014 |
Current U.S.
Class: |
75/338 ;
425/7 |
Current CPC
Class: |
B22F 2009/0888 20130101;
B22F 9/082 20130101; B22F 2009/0892 20130101; B22F 2009/0856
20130101; B22F 2009/088 20130101 |
International
Class: |
B22F 9/08 20060101
B22F009/08 |
Claims
1. A system for atomizing a molten material having a first material
composition, wherein the system comprises: a tundish configured to
hold the molten material; a nozzle in fluid communication with the
tundish, wherein the nozzle is comprised of a second material
having a second material composition, and wherein the second
material composition is substantially similar to the first material
composition; an internal channel defined in at least one of the
tundish or the nozzle; and a pump configured to pump a molten heat
transfer medium through the internal channel.
2. The system of claim 1, wherein the tundish is comprised of a
third material having a third material composition, and wherein the
third material composition is substantially similar to the first
material composition.
3. The system of claim 1, wherein the internal channel is defined
in the tundish, and wherein a second internal channel is defined in
the nozzle.
4. The system of claim 1, wherein the molten heat transfer medium
comprises a material selected from a group consisting of a salt, a
metal, and an alloy.
5. The system of claim 1, wherein the boiling point of the molten
heat transfer medium is greater than the boiling point of water at
atmospheric pressure.
6. The system of claim 1, further comprising a melt chamber,
wherein the tundish is positioned in the melt chamber.
7. The system of claim 6, further comprising a melting hearth and a
refining hearth positioned in the melt chamber.
8. The system of claim 7, further comprising an atomization
chamber, wherein the nozzle protrudes into the atomization
chamber.
9. The system of claim 1, wherein the molten heat transfer medium
comprises a molten salt.
10. A method for atomizing a molten material comprising a first
material composition, wherein the method comprises: passing the
molten material through an atomization nozzle comprised of a second
material comprising a second material composition, wherein the
second material composition is substantially similar to the first
material composition, and wherein an internal channel is defined in
the nozzle; and pumping a molten heat transfer medium through the
internal channel, wherein the molten heat transfer medium is
configured to affect heat transfer to and from the atomization
nozzle.
11. The method of claim 10, further comprising providing the molten
material to a tundish in fluid communication with the atomization
nozzle, wherein the tundish is comprised of a third material
comprising a third material composition, and wherein the third
material composition is substantially similar to the first material
composition.
12. The method of claim 11, wherein a second internal channel is
defined in the tundish, and wherein the method further comprises
pumping the molten heat transfer medium through the second internal
channel.
13. The method of claim 10, wherein the molten heat transfer medium
comprises a material selected from a group consisting of a salt, a
metal, and an alloy.
14. The method of claim 10, further comprising melting the molten
material.
15. The method of claim 14, further comprising refining the molten
material.
16. A method for regulating temperature in an atomizing system,
wherein the atomizing system comprises a nozzle, and wherein the
method comprises: pumping a molten heat transfer medium through an
internal channel in the nozzle to heat the nozzle; and pumping the
molten heat transfer medium through the internal channel in the
nozzle to cool the nozzle.
16. od of claim 16, further comprising obtaining a nozzle comprised
of a first material having a first material composition, and
wherein the first material composition is substantially similar to
the material composition of the atomized powder exiting the
atomizing system.
18. The method of claim 16, wherein the atomizing system further
comprises a tundish, and wherein the method further comprises
pumping the molten heat transfer medium through a second internal
channel in the tundish to cool the tundish.
19. The method of claim 18, wherein the tundish is comprised of a
second material having a second material composition, wherein the
second material composition is substantially similar to the
material composition of the atomized powder exiting the atomizing
system.
20. The method of claim 16, wherein heating of the nozzle occurs
during a pre-atomizing stage, and wherein cooling of the nozzle
occurs during an atomizing operation.
Description
BACKGROUND OF THE TECHNOLOGY
[0001] 1.Field of Technology
[0002] The present disclosure is directed to metal and metal alloy
atomizing systems and methods. More particularly, the present
disclosure is directed to apparatuses, systems, and methods for
producing clean atomized metal and metal alloy powders.
[0003] 2.Description of the Background of the Technology
[0004] During an atomizing operation, a heat of a metal or metal
alloy is heated to high temperature and subjected to high
pressures. Typically, during atomization operations starting
materials are heated to a molten state and subjected to
high-pressure atomizing jets to produce a powder from the molten
material. When subjected to such high-temperature, high-pressure
conditions, the material being atomized may be subjected to
contaminants that are within the system or which become entrained
as a result of erosion from the molten material. For example, the
molten material may react and/or combine with elements in the
atmosphere or other materials present in the atomizing system.
[0005] To prevent contamination of a molten material with elements
in the atmosphere, the atomizing operation may be conducted within
a chamber containing a non-reactive atmosphere. For example, molten
titanium and high temperature titanium alloys are often maintained
in a vacuum or in an inert atmosphere during certain stages of the
atomizing operation. In an electron beam cold hearth furnace, a
high or substantial vacuum is maintained in the melting and casting
chambers to allow the electron beam guns to operate. In a plasma
arc cold hearth furnace, plasma torches use an inert gas, such as
helium or argon, for example, to produce plasma. The atomization
jets in an atomizing system can also utilize an inert gas to
generate the atomized powder. Atomizing of titanium in a
nonreactive atmosphere, for example, is described in U.S. Pat. No.
5,084,091, entitled "Method for Producing Titanium Particles", the
entire disclosure of which is hereby incorporated herein by
reference.
[0006] To prevent erosion and contamination of the molten material
by other material(s) in the atomizing system, the molten material
can be isolated or separated from the other materials present in
the system. For example, a solidified skull of the material being
processed can physically separate the molten material from the
materials from which the hearth(s) and/or tundish are constructed
in a melting, refining, and/or atomizing system. Additionally or
alternatively, the hearth(s) and/or tundish can be lined with
ceramic or another high melting point material, which can isolate
or inhibit contact between the molten material and the other
materials in the system. The atomizing nozzle or a lining in the
nozzle may also be comprised of ceramic or other high melting point
material. An atomizing system including a ceramic nozzle, for
example, is described in U.S. Pat. No. 5,263,689, entitled
"Apparatus for Making Alloy Powders", the entire disclosure of
which is hereby incorporated herein by reference. Despite efforts
to isolate the molten material from other material(s) in the
atomizing system, erosion and/or contamination can still occur. For
example, ceramic material in the nozzle can contaminate the molten
material, which can produce inclusions or other defects in products
formed from the powdered material.
[0007] It would be advantageous to provide an atomizing system and
method that are less susceptible to erosion and contamination of
the molten and atomized material contained therein. It would also
be advantageous to provide improved thermal transfer to and from a
tundish and an atomization nozzle. More generally, it would be
advantageous to provide an improved atomizing system and method
adapted to process titanium, other reactive materials, and metals
and metal alloys generally.
SUMMARY
[0008] According to certain non-limiting embodiments, apparatuses,
systems, and methods for producing atomized powder of metals and
metal alloys are described.
[0009] Various non-limiting embodiments according to the present
disclosure are directed to a system for atomizing a molten material
selected from a molten metal and a molten metal alloy, the molten
material having a first material composition. The system comprises
a tundish configured to hold the molten material and a nozzle in
fluid communication with the tundish, wherein the nozzle is
comprised of a second material having a second material
composition, and wherein the second material composition is
identical or substantially identical to the first material
composition. The system for atomizing the molten material further
comprises an internal channel defined in at least one of the
tundish or the nozzle and a pump configured to pump a molten heat
transfer medium through the internal channel.
[0010] In certain non-limiting embodiments of the system according
to the present disclosure, the tundish is comprised of a third
material having a third material composition, and the third
material composition is identical or substantially identical to the
first material composition.
[0011] In certain non-limiting embodiments of the system according
to the present disclosure, the internal channel is defined in the
tundish, and a second internal channel is defined in the
nozzle.
[0012] In certain non-limiting embodiments of the system according
to the present disclosure, the molten heat transfer medium
comprises at least one material selected from a molten salt, a
molten metal, and a molten metal alloy.
[0013] In at least one non-limiting embodiment of the system
according to the present disclosure, the boiling point of the
molten heat transfer medium is greater than the boiling point of
water at atmospheric pressure.
[0014] In certain non-limiting embodiments, the system according to
the present disclosure further comprises a melt chamber, and the
tundish is positioned in the melt chamber. In certain non-limiting
embodiments, the system according to the present disclosure further
comprises a melting hearth and a refining hearth positioned in the
melt chamber. In at least one non-limiting embodiment, the system
according to the present disclosure further comprises an
atomization chamber, and the nozzle protrudes into the atomization
chamber.
[0015] In certain non-limiting embodiments of the system according
to the present disclosure, the molten heat transfer medium
comprises a molten salt.
[0016] Various non-limiting embodiments according to the present
disclosure are directed to a method for atomizing a molten material
selected from a molten metal and a molten metal alloy, the molten
material having a first material composition. The method comprises
passing the molten material through an atomization nozzle comprised
of a second material having a second material composition, wherein
the second material composition is identical or substantially
identical to the first material composition, and wherein an
internal channel is defined in the nozzle. The method further
comprises pumping a molten heat transfer medium through the
internal channel, wherein the molten heat transfer medium affects
heat transfer to and from the atomization nozzle.
[0017] In certain non-limiting embodiments, the method for
atomizing a molten material according to the present disclosure
comprises providing the molten material to a tundish in fluid
communication with the atomization nozzle, the tundish is comprised
of a third material having a third material composition, and the
third material composition is identical or substantially identical
to the first material composition.
[0018] In certain non-limiting embodiments of the method according
to the present disclosure, a second internal channel is defined in
the tundish, and the method further comprises pumping the molten
heat transfer medium through the second internal channel.
[0019] In certain non-limiting embodiments of the method according
to the present disclosure, the molten heat transfer medium is at
least one of a molten salt, a molten metal, and a molten alloy.
[0020] In at least one non-limiting embodiment, the method
according to the present disclosure further comprises melting
materials to provide the molten material.
[0021] Various non-limiting embodiments according to the present
disclosure are directed to a method for regulating temperature in
an atomizing system, wherein the atomizing system comprises a
nozzle, and wherein the method comprises pumping a molten heat
transfer medium through an internal channel in the nozzle to modify
a temperature of the nozzle. According to certain embodiments of
the method, the method includes pumping the molten heat transfer
medium through the internal channel in the nozzle to heat the
nozzle. According to certain embodiments of the method, the method
includes pumping the molten heat transfer medium through the
internal channel in the nozzle to cool the nozzle.
[0022] In certain non-limiting embodiments of the method for
regulating temperature in an atomizing system according to the
present disclosure, the method further comprises obtaining a nozzle
comprised of a first material having a first material composition,
and the first material composition is identical or substantially
identical to the material composition of the atomized powder
produced by the atomizing system.
[0023] In certain non-limiting embodiments of the method for
regulating temperature in an atomizing system according to the
present disclosure, the atomizing system further comprises a
tundish, and the method further comprises pumping the molten heat
transfer medium through a second internal channel in the tundish to
cool the tundish.
[0024] In certain non-limiting embodiments of the method for
regulating temperature in an atomizing system according to the
present disclosure, the atomizing system further comprises a
tundish, the method further comprises pumping the molten heat
transfer medium through a second internal channel in the tundish to
cool the tundish, and the tundish is comprised of a second material
having a second material composition that is identical or
substantially identical to the material composition of the atomized
powder produced by the atomizing system.
[0025] In at least one non-limiting embodiment of the method for
regulating temperature in an atomizing system according to the
present disclosure, the molten heat transfer medium is pumped
through the internal channel in the nozzle to heat the nozzle
during a pre-atomizing stage, and the molten heat transfer medium
is pumped through the internal channel in the nozzle to cool the
nozzle during an atomizing operation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The various non-limiting embodiments described herein may be
better understood by considering the following description in
conjunction with the accompanying drawings, in which:
[0027] FIG. 1 is a schematic showing aspects of an atomizing system
according to various non-limiting embodiments of the present
disclosure;
[0028] FIG. 2 is a schematic showing aspects of the tundish and
nozzle of the atomizing system illustrated in FIG. 1, according to
various non-limiting embodiments of the present disclosure; and
[0029] FIG. 3 is a flow chart of a process for using the atomizing
system illustrated in FIG. 1, according to various non-limiting
embodiments of the present disclosure.
DETAILED DESCRIPTION OF CERTAIN NON-LIMITING EMBODIMENTS
[0030] According to certain non-limiting embodiments of an
atomizing system according to the present disclosure, the atomizing
system can include a tundish and/or a nozzle having an internal
channel defined therein. The tundish and/or the nozzle can be
comprised of a material having a material composition that is
identical or substantially identical to a material composition of
the molten material positioned in and/or flowing through the
tundish and/or the nozzle. A molten heat transfer medium can flow
through the internal channel(s) to facilitate heat transfer to
and/or from the tundish and/or the nozzle. For example, the molten
heat transfer medium can heat the tundish and/or the nozzle to
prevent solidification of the molten material within the nozzle.
Also, in certain embodiments, the molten heat transfer medium can
cool the tundish and/or the nozzle as the molten material flows
through the tundish and/or the nozzle.
[0031] To prevent the erosion and contamination of molten material
by other materials in an atomizing system, an atomization nozzle
and/or tundish of non-limiting embodiments of an atomizing system
according to the present disclosure can be comprised of a material
having a material composition that is identical or substantially
identical to a material composition of the molten material. As used
herein, a first material composition is "substantially identical"
to a second material composition if the materials are of the same
base alloy composition or within 1 weight percent of the base alloy
elemental composition. Contamination of a first material having a
first material composition with a second material having a
"substantially identical" second material composition will not
significantly alter the properties of the first material. According
to one non-limiting example, if while a molten first material
having a first material composition is atomized through an
atomizing nozzle comprising a second material having a
substantially identical second material composition passes through
a nozzle, and the second material erodes and contaminates the first
material, the properties of the first material will not be
significantly altered by the contamination.
[0032] According to another non-limiting example, a first material
and a second material can be the same CP grade of titanium or the
same titanium alloy. However, the first material may have been
produced at a different location and/or at different time than the
second material. Rather than having identical material
compositions, the first material and the second material may have
minor compositional differences, and contamination of the first
material with the second material, or vice versa, will not
significantly alter the properties of the contaminated material. In
such case, as the phrase is used herein, the material composition
of the first material is substantially identical to the material
composition of the second material.
[0033] To prevent erosion and contamination of molten material
passing through an atomization nozzle, the material composition of
the molten material can be substantially identical to the material
composition of a material from which the atomization nozzle is
comprised. For example, the atomization nozzle can be ceramic-free,
and can also be free of other potential contaminants that would
significantly affect properties of powder produced from the molten
material. In certain non-limiting embodiments, the molten material
and the atomization nozzle can both be comprised of the same CP
titanium grade or titanium alloy; however, the titanium grade or
alloy may have been produced at different locations and/or
different times and not be produced in the same heat. As the molten
material and the atomization nozzle are comprised of materials
having substantially identical material compositions, nozzle
material that contaminates the molten material would not
significantly affect properties of powder produced from the molten
material.
[0034] The tundish can also be comprised of a material having a
material composition that is substantially similar to the material
composition of the molten material. For example, if the molten
material is comprised of a particular CP titanium grade or titanium
alloy, the tundish can also be comprised of the same CP titanium
grade or titanium alloy. Because the material composition of the
molten material is substantially identical to the material
composition of the tundish material, the tundish material would not
significantly affect the properties of the molten material if it
were to erode or dissolve in the molten material.
[0035] If an atomization nozzle is insufficiently heated prior to
and/or during the atomizing operation, the molten material flowing
through the nozzle may solidify and obstruct the nozzle opening.
Additionally, if the nozzle is overcooled during operation of the
atomizing system, high thermal stresses between the nozzle and the
molten material may result in fracturing of the nozzle.
[0036] To provide adequate thermal transfer between the nozzle and
the molten material, a molten heat transfer medium can be used in
non-limiting embodiments of systems and methods according to the
present disclosure. For example, a molten heat transfer medium can
be used instead of conventional coolant for an atomizing nozzle,
which typically is or is comprised of water. The molten heat
transfer medium according to the present invention can comprise at
least one of a molten metal, a molten alloy, or a molten salt, for
example. To facilitate heating and/or cooling of the atomization
nozzle, the molten heat transfer medium can be circulated through
one or a plurality of internal channels in the nozzle. Additionally
or alternatively, a molten heat transfer medium can be pumped
through one or a plurality of internal channels in the tundish of
an atomizing system according to the present disclosure, for
example, and the molten heat transfer medium can facilitate thermal
transfer between the tundish and the molten material.
[0037] The molten heat transfer medium can have a boiling point
that is greater than the boiling point of water at atmospheric
pressure. As a result, the molten heat transfer medium can more
effectively be maintained at higher temperatures than water. Water
can maintain a temperature of approximately 140.degree. F.
(60.degree. C.), for example, while in various non-limiting
embodiments according to the present disclosure a molten heat
transfer medium can maintain temperatures between 500.degree. F.
(260.degree. C.) and 900.degree. F. (482.degree. C.), for example.
In other instances, the molten heat transfer medium can maintain
temperatures below 500.degree. F. (260.degree. C.) or above
900.degree. F. (482.degree. C.), for example. Accordingly, the
molten heat transfer medium can be heated to and maintain higher
temperatures within the internal channels than can be achieved with
conventional water or predominantly water-based coolant. In various
embodiments of the present system and method, the molten heat
transfer medium can assume and maintain a temperature that is
greater than the temperature achievable by conventional water or
predominantly water-based coolant and less than the temperature of
the molten material in the tundish.
[0038] The higher temperature of the molten heat transfer medium
(relative to conventional coolant) can facilitate heating of the
nozzle. For example, the nozzle can be heated by the molten heat
transfer medium, circulating as coolant, to a temperature higher
than could be achieved with conventional water or a predominantly
water-based coolant. Heating the nozzle to higher temperatures can
prevent or inhibit undesirable cooling and freezing of the molten
material within the nozzle. For example, certain molten alloys
atomized to powder can have solidus temperatures up to 3000.degree.
F. (1649.degree. C.), and the molten heat transfer medium according
to the present disclosure can heat the nozzle to temperatures
closer to 3000.degree. F. (1649.degree. C.) than can be achieved
using conventional water or predominantly water-based nozzle
coolants. Because the molten heat transfer medium according to the
present disclosure facilitates heating the nozzle to higher
temperatures than can be achieved using conventional coolant,
unintentional obstruction of the atomizing nozzle can be prevented
or inhibited.
[0039] Additionally, because the molten heat transfer medium can
achieve a higher temperature than water, the temperature difference
between the molten heat transfer medium and the molten material
processed in the atomizing system is reduced. Consequently, the
temperature difference between the tundish and/or the nozzle in an
atomizing system according to the present disclosure may be reduced
relative to certain conventional atomizing systems. This reduced
temperature differential can reduce thermal shock effects to and
the incidence of cracking of the nozzle and/or the tundish.
Moreover, because the molten heat transfer medium according to the
present disclosure can be maintained at a temperature closer to the
temperature of the molten material than can be achieved with water,
the incidence of overcooling of the tundish and/or the nozzle by
contact with the molten heat transfer medium can be avoided or
reduced.
[0040] FIG. 1 schematically illustrates certain elements of an
atomizing system 100 according to one non-limiting embodiment of
the present invention configured to produce powders of metals and
metal alloys. The atomizing system 100 includes a melting hearth
110 and a refining hearth 120. In various non-limiting embodiments,
feed materials 102 can enter the atomizing system 100 at an inlet
or material feed 104. For example, solid material 102, which may
include, for example, sponge, revert, master alloys, and other
alloying input materials can enter the melting hearth 110 at the
inlet 104. An energy source 116 can energize the solid material 102
to generate molten material 112. In various non-limiting
embodiments, the energy source 116 may be, for example, an electron
beam gun or other electron generating device or a plasma torch. In
other non-limiting embodiments, the energy source 116 can include
an electron beam gun, for example. The melting hearth 110 and the
refining hearth 120 may be configured so that the molten material
112 flows along the melting hearth 110 and to the refining hearth
120 along a path 118. In various non-limiting embodiments, an
energy source 126, such as, for example, a plasma torch, an
electron beam gun, or another electron generating device can
energize the molten material 112 in the refining hearth 120 to heat
and refine the molten material 112.
[0041] In various non-limiting embodiments, the melting hearth 110
and/or the refining hearth 120 can be comprised of copper. For
example, the melting hearth 110 and the refining hearth 120 can
comprise copper hearths. Additionally, in certain non-limiting
embodiments, the melting hearth 110 and/or the refining hearth 120
can include internal channels through which a coolant such as, for
example, water or a predominantly water-based fluid can circulate
to cool the hearths 110, 120. Accordingly, in certain non-limiting
embodiments the hearths 110, 120 can comprise water-cooled copper
hearths. In the depicted non-limiting embodiment shown in FIG. 1, a
skull 114 of the molten material that has solidified (frozen) on
the melting hearth 110 separates the molten material 112 from the
melting hearth 110. Additionally, in the depicted, non-limiting
embodiment, a skull 124 of material on the refining hearth 120
separates the molten material 112 from the refining hearth 120. In
such non-limiting embodiments, the skulls 114, 124 of solid
material can prevent erosion and/or contamination of the molten
material 112 by the copper hearths 110, 120.
[0042] Referring still to FIG. 1, the atomizing system 100 can
further include a tundish 140. The tundish 140 can receive the
molten material 112 from the refining hearth 120. For example, the
molten material 112 can flow along a path 128 and/or through a pool
130 between the refining hearth 120 and the tundish 140. As
described in greater detail herein, the tundish 140 can include one
or a plurality of internal channels through which the molten heat
transfer medium circulates.
[0043] In various non-limiting embodiments of an atomizing system
according to the present disclosure, the melting hearth 110, the
refining hearth 120, and the tundish 140 can be disposed within a
sealed melt chamber 150. In various embodiments, the melt chamber
150 can contain an environment that does not react with the molten
material. For example, a vacuum or substantial vacuum can be
maintained within the melt chamber 150 if electron beam devices or
other electron generating devices are used to melt, heat, and/or
refine material within the melt chamber 150. In embodiments in
which a plasma torch device is used to melt, heat, and/or refine
material within the melt chamber 150, the environment within the
melt chamber may include an inert gas, such as helium or argon, for
example.
[0044] Referring now to FIGS. 1 and 2, in the schematically
illustrated non-limiting embodiment of system 100, the tundish 140
is in fluid communication with an atomizing nozzle 160. The
depicted nozzle 160 extends between the tundish 140 positioned in
the melt chamber 150 and an atomization chamber 152 in which
atomized powder is formed. For example, in the system 100, the
nozzle 160 depicted in FIGS. 1 and 2 provide the only connection
between the melt chamber 150 and the atomization chamber 152. The
nozzle 160 can direct and control the molten material 112 in the
tundish 140 to enter the atomization chamber 152. For example, the
nozzle 160 can act as a throttling mechanism to stabilize the
stream 162 of molten metal 112 entering the atomization chamber
152. Additionally, the molten material 112 in the nozzle 160 can
act as a seal between the environment in the atomization chamber
152 and the environment in the melting chamber 150. In certain
non-limiting embodiments, the nozzle 160 can be separate and
distinct from the tundish 140 or, in other non-limiting
embodiments; the nozzle 160 can be integrally formed with the
tundish 140, for example.
[0045] In various non-limiting embodiments, the material
composition of the molten material 112 can be identical or
substantially identical to the material composition of material
comprising the tundish 140 and/or the atomization nozzle 160. For
example, the tundish 140 and/or the atomization nozzle 160 can be
ceramic-free, as well as free of other potential harmful
contaminants. In certain non-limiting embodiments, for example, the
molten material 112, the tundish 140, and the atomization nozzle
160 can be comprised of a particular alloy, such as Ti-6Al-4V
alloy, for example. However, the Ti-6Al-4V alloy of the molten
material 112, the tundish 140 and/or the nozzle 160 may have been
produced at different locations and/or different times and,
therefore, may vary in composition to some degree, although
remaining within the required compositional specification for
Ti-6Al4V alloy. Because the molten material 112, the tundish 140,
and the atomization nozzle 160 are comprised of substantially
identical materials, erosion and/or problematic contamination of
the molten material 112 by contact with the tundish 140 and/or the
nozzle 160 is avoided. For example, if material from the tundish
140 and/or the nozzle 160 contaminates the molten material 112, but
the materials are substantially identical in composition, the
contaminants do not significantly affect properties of the molten
material 112 or the powder formed from the molten material 112.
[0046] In various non-limiting embodiments, one or a plurality of
internal channels 142 can be defined within the tundish 140 and/or
the nozzle 160. For example, referring primarily to FIG. 2, a
channel 142 is defined within the tundish 140. The channel 142 can
extend from an inlet 144 in the tundish 140 to an outlet 146 in the
tundish 140. In certain instances, a plurality of channels 142 can
be defined within the tundish 140. The plurality of channels 142
can be fluidly connected, for example, or can define multiple
discrete fluid paths, for example. In various non-limiting
embodiments, a channel 142 or a plurality of channels 142 can be
defined in the nozzle 160. In certain non-limiting embodiments, at
least one channel in the nozzle 160 can be fluidly connected to at
least one channel in the tundish 140.
[0047] In various non-limiting embodiments, the internal channels
142 can be formed in the tundish 140 and/or the nozzle 160 by
casting or by other conventional techniques. For example, the
channels 142 can be produced using additive manufacturing
techniques. In various non-limiting embodiments, the channels 142
are formed relatively close to surfaces of the tundish 140 and/or
the nozzle 160 that are contacted by the molten material 112
positioned in the tundish 140 and passing through the nozzle 160.
For example, in certain non-limiting embodiments the channels 142
can be positioned less than 0.12 inch (3 mm) from the surfaces of
the tundish 140 and/or the nozzle 160 contacted by the molten
material during the atomization process, e.g., the outer surfaces
of the tundish 140. In certain non-limiting embodiments, the
channels 142 can be positioned less than 0.5 inches (13 mm) from
the outer surfaces of the tundish 140. In still other non-limiting
embodiments, the channels 142 can be positioned between 0.12 inch
(3 mm) and 1.0 inch (25 mm) from the outer surfaces of the
tundish.
[0048] In certain conventional tundishes, the channels are
positioned farther from the outer surface of the tundish. For
example, in a conventional tundish of that type, the channels may
be positioned between 0.5 inches (13 mm) and 1.0 inches (25 mm)
from the outer surface of the tundish.
[0049] The channels 142 can be configured to allow a heat transfer
material to flow through the tundish 140 and/or the nozzle 160. In
certain non-limiting embodiments, the heat transfer material can
comprise a molten heat transfer medium, such as a molten mineral
substance, for example. In various non-limiting embodiments, the
molten heat transfer medium can include at least one of a molten
metal, a molten alloy, and a molten salt. For example, the molten
heat transfer medium can be comprised of molten sodium. The boiling
point of the molten heat transfer medium can exceed the boiling
point of water. For example, the boiling point of molten sodium is
1650.degree. F. (899.degree. C.).
[0050] Referring primarily to FIG. 2, in certain non-limiting
embodiments, a preheating device, such as, for example, a radiant
preheating element 148, can be positioned adjacent or around the
tundish 140. The preheating element 148 can comprise a plurality of
coils 149 configured to heat the tundish 140 before the molten heat
transfer medium is introduced through the channels 142. In such
instances, preheating of the tundish 140 can prevent or inhibit the
molten heat transfer medium from freezing within the channels 142
when the molten heat transfer medium is introduced into the
channels 142.
[0051] In various non-limiting embodiments, the atomizing system
100 can include a pump 170, which can be configured to pump the
molten heat transfer medium from a source 180 into and through the
channels 142. The pump 170 can comprise an electromagnetic pump,
for example, that can pump high-temperature molten material through
the channels 142. For example, commercially available
electromagnetic pumps having suitable performance characteristics
are available from CMI Novacast, Inc., Des Plaines, Ill. Such pumps
can pump molten aluminum, zinc, sodium, mercury, potassium, NaK,
and magnesium, for example, and can pump these materials at high
temperatures, such as temperatures up to 1472.degree. F.
(800.degree. C.), for example.
[0052] Referring to FIGS. 1 and 2, at least one atomization jet 164
can be positioned within the atomization chamber 152, for example.
The atomization jet(s) 164 emit a high-pressure stream of gas or
another fluid. The atomization jet(s) 164 can be directed toward
the stream 162 of the molten material 112 exiting the nozzle 160.
For example, in certain instances, the atomization jet(s) 164 can
form a gas ring. In other instances, the jet(s) 164 can be arranged
in alternative configurations. In various non-limiting embodiments,
the atomization jet(s) 164 can force an inert gas, such as helium
or argon, for example, into the stream 162 of the molten material
112. In such instances, the pressure exerted by the atomization
jet(s) 164 can freeze the molten material into a particulate form
and produce a flume 166 of powered material within the atomization
chamber 160.
[0053] In various non-limiting embodiments, the atomization chamber
152 can comprise a chamber that is sealed from the outside
environment. Moreover, in certain instances, the atomization
chamber 152 can comprise an environment that does not react with
the molten material or the powder formed from the molten material.
For example, the atomization chamber 152 can comprise an inert gas,
such as helium or argon, for example. In various non-limiting
embodiments, the atomization chamber 152 can comprise a first inert
gas and the melt chamber 150 can comprise a second, different inert
gas. For example, the atomization jet(s) 164 can expel argon into
the atomization chamber 152 such that the atomization chamber 152
comprises argon, and the melt chamber 150 can comprise a different
inert gas, such as, for example, helium.
[0054] In certain non-limiting embodiments of system 100, the
atomization chamber 152 can be isolated from the melt chamber 150.
For example, the molten material 112 flowing through the nozzle 160
can form a seal or barrier between the melt chamber 150 and the
atomization chamber 152. In such instances, gases and/or
contaminants from the melt chamber 150 can be prevented from
entering the atomization chamber 152.
[0055] Referring now to FIG. 3, a process for using the atomizing
system 100 illustrated schematically in FIGS. 1 and 2 is depicted.
At step 190, a preheating device, such as the radiant preheating
element 148 (see FIG. 2) can be activated. Activation of the
preheating element 148 can heat a tundish, such as the tundish 140
(see FIGS. 1 and 2), for example. Referring still to FIG. 3, the
preheating element 148 can be activated before the molten heat
transfer medium is introduced into the channels 142 (FIG. 2) in the
tundish 140 and/or the nozzle 160 (FIGS. 1 and 2). In such
instances, preheating of the tundish 140 can prevent the molten
heat transfer medium from freezing within the channels 142 when it
is introduced into the channels (at step 192, for example).
[0056] Referring still to FIG. 3, at step 192, a pump, such as the
pump 170 (FIGS. 1 and 2), for example, can be activated. Activation
of the pump 170 can initiate pumping of the molten heat transfer
medium into and through the internal channels 142 (FIG. 2) in the
tundish 140 and/or the nozzle 160 (FIGS. 1 and 2). The molten heat
transfer medium can flow through the internal channels 142 to heat
the tundish 140 and/or the nozzle 160 at step 194. In such
non-limiting embodiments of the system 100, the molten heat
transfer medium can be at a temperature greater than the
temperature achievable using water or a predominantly water-based
heat transfer medium as a coolant, for example, but also can be at
a temperature that is less than the temperature of the molten
material 112 (FIGS. 1 and 2) in the system 100 (FIGS. 1 and 2), for
example. The molten heat transfer medium can heat the tundish 140
to a suitable temperature to facilitate the flow of the molten
material 112 through the tundish 140 and the nozzle 160, and into
the atomization chamber 152 (FIGS. 1 and 2), where it is atomized
to a powder.
[0057] At step 196 of the process shown in FIG. 3, the molten
material 112 can be atomized. For example, the atomization jets 164
(FIGS. 1 and 2) can force a gas into the stream 162 (FIGS. 1 and 2)
of the molten material 112 exiting the nozzle 160. The atomization
jets 164 can create a powder flume 166 (FIGS. 1 and 2) from the
molten material 112 in the stream 164. As the jets 164 atomize the
molten material 112, the molten heat transfer medium can flow
through the internal channels 142 in the tundish 140 and/or the
nozzle 160 at step 198. In such instances, the molten heat transfer
medium can cool the tundish 140 and/or the nozzle 160 during
continuous operation of the atomizing system 100. Although the
present system and method is advantageously applied to processing
very reactive metals and metal alloys, it may also be applied to
other alloys. For example, the present system and method may be
applied to nickel based alloys, cobalt based alloys, and iron based
alloys, and especially where extremely clean alloy material is
required.
[0058] It is to be understood that various descriptions of the
disclosed non-limiting system and method embodiments have been
simplified to illustrate only those features, aspects,
characteristics, and the like that are relevant to a clear
understanding of the disclosed embodiments, while eliminating, for
purposes of clarity, other features, aspects, characteristics, and
the like. Persons having ordinary skill in the art, upon
considering the present description of the disclosed non-limiting
embodiments, will recognize that other features, aspects,
characteristics, and the like may be desirable in a particular
implementation or application of the disclosed embodiments.
However, because such other features, aspects, characteristics, and
the like may be readily ascertained and implemented by persons
having ordinary skill in the art upon considering the present
description of the disclosed embodiments, and are, therefore, not
necessary for a complete understanding of the disclosed
embodiments, a description of such features, aspects,
characteristics, and the like is not provided herein. As such, it
is to be understood that the description set forth herein is merely
exemplary and illustrative of the disclosed non-limiting
embodiments and is not intended to limit the scope of the invention
as defined solely by the claims.
[0059] In the present disclosure, other than where otherwise
indicated, all numbers expressing quantities or characteristics are
to be understood as being prefaced and modified in all instances by
the term "about." Accordingly, unless indicated to the contrary,
any numerical parameters set forth in the following description may
vary depending on the desired performance and other properties one
seeks to obtain in the embodiments according to the present
disclosure. For example, the term "about" can refer to an
acceptable degree of error for the quantity measured, given the
nature or precision of the measurement. Typical exemplary degrees
of error may be within 20%, within 10%, or within 5% of a given
value or range of values. At the very least, and not as an attempt
to limit the application of the doctrine of equivalents to the
scope of the claims, each numerical parameter described in the
present description should at least be construed in light of the
number of reported significant digits and by applying ordinary
rounding techniques.
[0060] Also, any numerical range recited herein is intended to
include all sub-ranges subsumed therein. For example, a range of "1
to 10" is intended to include all sub-ranges between (and
including) the recited minimum value of 1 and the recited maximum
value of 10, that is, having a minimum value equal to or greater
than 1 and a maximum value equal to or less than 10. Any maximum
numerical limitation recited herein is intended to include all
lower numerical limitations subsumed therein, and any minimum
numerical limitation recited herein is intended to include all
higher numerical limitations subsumed therein. Accordingly,
Applicants reserve the right to amend the present disclosure,
including the claims, to expressly recite any sub-range subsumed
within the ranges expressly recited herein. All such ranges are
intended to be inherently disclosed herein such that amending to
expressly recite any such sub-ranges would comply with the
requirements of 35 U.S.C. .sctn.112, first paragraph, and 35 U.S.C.
.sctn.132(a).
[0061] The grammatical articles "one", "a", "an", and "the", as
used herein, are intended to include "at least one" or "one or
more", unless otherwise indicated. Thus, the articles are used
herein to refer to one or more than one (i.e., to at least one) of
the grammatical objects of the article. By way of example, "a
component" means one or more components, and thus, possibly, more
than one component is contemplated and may be employed or used in
an implementation of the described embodiments.
[0062] Any patent, publication, or other disclosure material that
is said to be incorporated by reference herein, is incorporated
herein in its entirety unless otherwise indicated, but only to the
extent that the incorporated material does not conflict with
existing definitions, statements, or other disclosure material
expressly set forth in this disclosure. As such, and to the extent
necessary, the express disclosure as set forth herein supersedes
any conflicting material incorporated by reference herein. Any
material, or portion thereof, that is said to be incorporated by
reference herein, but which conflicts with existing definitions,
statements, or other disclosure material set forth herein is only
incorporated to the extent that no conflict arises between that
incorporated material and the existing disclosure material.
Applicant reserves the right to amend the present disclosure to
expressly recite any subject matter, or portion thereof,
incorporated by reference herein.
[0063] The present disclosure includes descriptions of various
non-limiting embodiments. It is to be understood that all
embodiments described herein are exemplary, illustrative, and
non-limiting. Thus, the invention is not limited by the description
of the various exemplary, illustrative, and non-limiting
embodiments. Rather, the invention is defined solely by the claims,
which may be amended to recite any features expressly or inherently
described in or otherwise expressly or inherently supported by the
present disclosure. Therefore, any such amendments would comply
with the requirements of 35 U.S.C. .sctn.112, first paragraph, and
35 U.S.C. .sctn.132(a).
[0064] The various non-limiting embodiments disclosed and described
herein can comprise, consist of, or consist essentially of, the
features, aspects, characteristics, limitations, and the like, as
variously described herein. The various non-limiting embodiments
disclosed and described herein can also comprise additional or
optional features, aspects, characteristics, limitations, and the
like, that are known in the art or that may otherwise be included
in various non-limiting embodiments as implemented in practice.
[0065] The present disclosure has been written with reference to
various exemplary, illustrative, and non-limiting embodiments.
However, it will be recognized by persons having ordinary skill in
the art that various substitutions, modifications, or combinations
of any of the disclosed embodiments (or portions thereof) may be
made without departing from the scope of the invention as defined
solely by the claims. Thus, it is contemplated and understood that
the present disclosure embraces additional embodiments not
expressly set forth herein. Such embodiments may be obtained, for
example, by combining, modifying, or reorganizing any of the
disclosed steps, ingredients, constituents, components, elements,
features, aspects, characteristics, limitations, and the like, of
the embodiments described herein. Thus, this disclosure is not
limited by the description of the various exemplary, illustrative,
and non-limiting embodiments, but rather solely by the claims. In
this manner, Applicants reserve the right to amend the claims
during prosecution to add features as variously described
herein.
* * * * *