U.S. patent application number 14/192921 was filed with the patent office on 2015-09-03 for system and process for producing a metallic article.
This patent application is currently assigned to Ford Motor Company. The applicant listed for this patent is Ford Motor Company. Invention is credited to Darryl Leigh Young.
Application Number | 20150246383 14/192921 |
Document ID | / |
Family ID | 53942504 |
Filed Date | 2015-09-03 |
United States Patent
Application |
20150246383 |
Kind Code |
A1 |
Young; Darryl Leigh |
September 3, 2015 |
SYSTEM AND PROCESS FOR PRODUCING A METALLIC ARTICLE
Abstract
According to one or more embodiments, a hot-stamping device
includes first and second die portions including an alloy of metal
M, the alloy of metal M having higher heat conductivity than
ferrous alloy, and a cooling circuit in communication with at least
one of the first and second die portions. The metal M may be
copper. The alloy of metal M may include greater than 50 percent by
weight of metal M. The first and second die portions may each
independently include a greater than 50 percent by weight of the
alloy of metal M.
Inventors: |
Young; Darryl Leigh;
(Canton, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ford Motor Company |
Dearborn |
MI |
US |
|
|
Assignee: |
Ford Motor Company
Dearborn
MI
|
Family ID: |
53942504 |
Appl. No.: |
14/192921 |
Filed: |
February 28, 2014 |
Current U.S.
Class: |
72/342.3 ;
72/372 |
Current CPC
Class: |
B21D 37/16 20130101;
B21D 37/01 20130101; B21D 22/022 20130101 |
International
Class: |
B21D 37/16 20060101
B21D037/16; B21D 22/06 20060101 B21D022/06; B21D 22/02 20060101
B21D022/02 |
Claims
1. A hot-stamping device comprising: first and second die portions
including an alloy of metal M, the alloy of metal M having higher
heat conductivity than ferrous alloy; and a cooling circuit in
communication with at least one of the first and second die
portions.
2. The hot-stamping device of claim 1, wherein the metal M is
copper.
3. The hot-stamping device of claim 1, wherein the alloy of metal M
includes greater than 50 percent by weight of metal M.
4. The hot-stamping device of claim 1, wherein the first and second
die portions each independently include a greater than 50 percent
by weight of the alloy of metal M.
5. The hot-stamping device of claim 1, wherein the first and second
die portions include first and second surface sections,
respectively, the first and second surface sections together
defining a cavity and each independently including the alloy of
metal M.
6. The hot-stamping device of claim 5, wherein the first and second
die portions include first and second body sections adjacent the
first and second surface sections, respectively, the first and
second body sections independently including at least 20 percent by
weight of the alloy of metal M less than the first and second
surface sections, respectively.
7. The hot-stamping device of claim 1, wherein the cooling circuit
includes a number of cooling channels contacting at least one of
the first and second die portions.
8. The hot-stamping device of claim 5, wherein the cooling circuit
includes a number of cooling channels contacting at least one of
the first and second surface sections.
9. The hot-stamping device of claim 8, wherein the number of
cooling channels includes ferrous alloy.
10. The hot-stamping device of claim 1, wherein the alloy of metal
M includes at least one of beryllium, tin and zinc.
11. A hot-stamping device comprising: first and second die portions
each including a copper alloy, the copper alloy including greater
than 50 percent by weight of copper; and a cooling circuit in
communication with at least one of the first and second die
portions.
12. The hot-stamping device of claim 11, the first and second die
portions each independently include greater than 50 percent by
weight of the copper alloy.
13. The hot-stamping device of claim 11, wherein the first and
second die portions include first and second surface sections,
respectively, the first and second surface sections together
defining a cavity and each independently including the copper
alloy.
14. The hot-stamping device of claim 13, wherein the first and
second die portions include first and second body sections adjacent
the first and second surface sections, respectively, the first and
second body sections independently including at least 20 percent by
weight of the copper alloy less than the first and second surface
sections, respectively.
15. The hot-stamping device of claim 11, wherein the cooling
circuit includes a number of cooling channels including ferrous
alloy and contacting at least one of the first and second die
portions.
16. The hot-stamping device of claim 14, wherein the cooling
circuit includes a number of cooling channels including ferrous
alloy and contacting at least one of the first and second surface
sections.
17. A method of hot-stamping, comprising: subjecting a metallic
part to a cavity defined by first and second die portions, at least
one of the first and second die portions including an alloy of
metal M, the alloy of metal M having a higher heat conductivity
than ferrous alloy.
18. The method of claim 17, further comprising contacting at least
one of the first and second die portions including the alloy of
metal M with a number of cooling channels.
19. The method of claim 18, further comprising forming the number
of cooling channels via casting.
20. The method of claim 17, further comprising contacting the
metallic part with both of the first and second die portions to
effect compression.
Description
TECHNICAL FIELD
[0001] The disclosed inventive concept relates generally to system
and method for producing a metallic article.
BACKGROUND
[0002] In certain existing methods, draw/form dies for hot-stamping
are often expensive to build, expensive to maintain and have
relatively short service lives compared to dies used in cold
stamping conducted at ambient temperatures. In hot-stamping, the
high temperatures of the blank which enters the die with an entry
temperature of around 800 to 850 degrees Celsius promote wear
related failure mechanisms including galling, thermal checking such
as surface fatigue, and decarburization, all of which tend to
soften the die's surface and make the die vulnerable to abrasive
wear.
[0003] It would thus be advantageous if system and method for
producing a metallic article may be provided to solve one or more
of these identified problems.
SUMMARY
[0004] The disclosed inventive concept is believed to overcome one
or more of the problems associated with producing a metallic
article.
[0005] In one or more embodiments, a hot-stamping device includes
first and second die portions including an alloy of metal M, the
alloy of metal M having higher heat conductivity than ferrous
alloys, and a cooling circuit in communication with at least one of
the first and second die portions. In certain instances, the
cooling circuit includes a number of cooling channels made of
ferrous alloys.
[0006] The metal M may be copper. The alloy of metal M may include
greater than 50 percent by weight of metal M. The first and second
die portions may each independently include greater than 50 percent
by weight of the alloy of metal M.
[0007] The first and second die portions may include first and
second surface sections, respectively, the first and second surface
sections together defining a cavity and each independently
including the alloy of metal M.
[0008] The first and second die portions may include first and
second body sections adjacent the first and second surface
sections, respectively, the first and second body sections
independently including at least 20 percent by weight of the alloy
of metal M less than the first and second surface sections,
respectively.
[0009] In one or more other embodiments, a method of hot-stamping
includes subjecting a metallic part to a hot-stamping device as
described herein.
[0010] The above advantages and other advantages and features will
be readily apparent from the following detailed description of
embodiments when taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more complete understanding of embodiments of this
invention, reference should now be made to the embodiments
illustrated in greater detail in the accompanying drawings and
described below by way of examples wherein:
[0012] FIG. 1 illustratively depicts a system for producing a
metallic article according to one or more embodiments;
[0013] FIG. 2 illustratively depicts a non-limiting process for
producing the metallic article referenced in FIG. 1;
[0014] FIG. 3A illustratively depicts a partial exploded view of
the system referenced in FIG. 1;
[0015] FIG. 3B illustratively depicts a cross-sectional view (not
to scale) of the system referenced in FIG. 3A;
[0016] FIG. 4 illustratively depicts an alternative partial
exploded view of the system referenced in FIG. 1;
[0017] FIG. 5A illustratively depicts an alternative partial
exploded view of the system referenced in FIG. 1; and
[0018] FIG. 5B illustratively depicts a cross-sectional view (not
to scale) of the system referenced in FIG. 5A.
DETAILED DESCRIPTION OF ONE OR MORE EMBODIMENTS
[0019] As referenced in the FIGS., the same reference numerals are
used to refer to the same components. In the following description,
various operating parameters and components are described for
different constructed embodiments. These specific parameters and
components are included as examples and are not meant to be
limiting.
[0020] As is described herein elsewhere, the present invention in
one or more embodiments is advantageous at least in that
hot-stamping dies may be built from a material that provides
relatively greater heat conductivity and hence more efficient
cooling for quenching the drawn/stamped part. The material may
include a metal or metal alloy that is not only suitable for the
hot-stamping environment but also provides one or more benefits
that cannot be readily delivered by the existing ferrous alloys
such as iron or steel.
[0021] In one or more embodiments, and as illustratively depicted
in FIG. 1, a hot-stamping device generally shown at 100 includes a
stamping press 110, first and second die portions 112, 114 located
in the stamping press 110 and including an alloy of metal M, the
alloy of metal M having higher heat conductivity than ferrous
alloy, and a cooling circuit 116 in communication with at least one
of the first and second die portions 112, 114.
[0022] For illustration purposes, only two pairs of first and
second die portions 112, 114 are depicted in FIG. 1. However, the
hot-stamping device 100 does not have to be limited to only two
pairs of first and second die portions 112, 114. When needed, less
or more than one two sets of first and second die portions 112, 114
may be employed and be employed in any suitable arrangements.
[0023] The hot-stamping device 100 may be used in connection with
one or more other components which can be collectively referred as
a hot-stamping system generally shown at 102 as referenced in FIG.
1.
[0024] FIG. 2 illustratively depicts a process generally shown at
200 for making a metallic article referenced in FIG. 1. In a
non-limiting example, and as depicted in FIG. 1 in view of FIG. 2,
a metallic source material is provided via a source stand 120 to a
table cutter 108; and there the metallic source material is cut
into desirable shapes to form one or more metallic parts 118. This
step is also referenced as step 202 in FIG. 2.
[0025] At step 204, one or more of the metallic parts 118 may be
transferred to a furnace 104 either manually or via a robot 106.
The one or more metallic parts are heated to an elevated
temperature within the furnace 104 at step 206.
[0026] Immediately after the heating, the one or more metallic
parts 118 may be removed at step 208, optionally via another robot
(not shown), to be placed within a cavity 122 defined by the cavity
122.
[0027] At step 210, the metallic part 118 is stamped by the first
and second die portions 112, 114 to adopt the shape defined by the
opposing surfaces of the first and second die portions 112,
114.
[0028] During the stamping and compressing, the first and second
die portions 112, 114 may each be independently cooled by being in
communication with the cooling circuit 116. The cooling effect may
be imparted onto the first and second die portions 112, 114 via a
flow of cold liquid such as cold water delivered through the
cooling circuit 116. Because at least one of the first and second
die portions 112, 114 include the alloy of metal M which has
relatively greater heat conductivity, the cooling effect delivered
by the cooling circuit 116 is enhanced by the use of the first and
second die portions 112, 114 including the alloy of metal M.
Consequently, the metallic part 118 may be cooled more effectively
and quickly by being in contact with the first and second die
portions 112, 114. A relatively quicker cooling or quenching
affords the metallic part 118 as stamped with relatively greater
strength and desirable metallic structure.
[0029] The metal M may be of any suitable metal, provided that the
alloy of metal M has a higher heat conductivity than ferrous alloy.
Without wanting to be limited to any particular theory, it is
believed that the alloy of metal M has a substantial impact on
thermal conductivity in comparison to its corresponding neat metal
M. In addition, different metal alloys may also have measurable
differences in thermal conductivity. In the case for copper, it is
generally accepted that copper alloys as a group may be several
times more thermal conductive than ferrous alloys.
[0030] A non-limiting list of metal M includes copper, silver and
aluminum. In certain instances, the metal M is copper.
[0031] The alloy of the metal M may take any suitable form.
Non-limiting examples of the alloy of the metal M include copper
alloyed with one or more of beryllium, tin and zinc. Without
wanting to be limited to any particular theory, it is believed that
beryllium helps create strength, tin helps make bronze and zinc
helps make brass.
[0032] The metal M may be greater than 50 percent by weight of the
alloy of metal M. Alloy families are typically identified by the
metal element which makes up the majority of the composition. By
way of example, a copper based alloy would contain 50% or more
elemental copper by weight. Silver alloys may be used; however,
silver alloys may be too expensive relative to copper alloys.
Aluminum alloys may also be used; however, aluminum alloys may not
have the necessary compressive strength.
[0033] The first and second die portions 112, 114 may each
independently include a greater than 50 percent by weight of the
alloy of metal M. A non-limiting consideration here is that the
first and second die portions 112, 114 may merely include the alloy
of metal M but not entirely be made of the latter for monetary
considerations. In these designs, the base of the first and second
die portions 112, 114 may be a ferrous alloy such as cast iron,
cast steel and/or wrought steel.
[0034] In certain instances, and as depicted in FIG. 3A, the first
and second die portions 112, 114 may each include first and second
surface sections 302, 304 together defining the cavity 122 therein
between, the first and second surface sections 302, 304 each
independently including the alloy of metal M. The first and second
die portions may each include first and second body sections 308,
310 adjacent the first and second surface sections 302, 304,
respectively. This may be a design wherein the first and second
body sections 308, 310 may be constructed of a relatively more cost
efficient material while the relatively enhanced heat conductivity
is delivered by the first and second surface sections 302, 304
which contact the metallic part 118 to be inserted within the
cavity 122. The thickness or weight of the first and second surface
sections 302, 304 may be varied relative to the thickness or weight
of the first and second body sections 308, 310 according to certain
specific requirements of the stamping project at hand. For
instance, the relative thickness or weight may be varied according
to the size of the metallic part 118 and/or the resultant cooling
requirement specific to the metallic part 118.
[0035] However, a general direction is that the first and second
surface sections 302, 304 should each independently contain
relatively more of the alloy of metal M than the first and second
body sections 308, 310. In certain instances, the first and second
body sections 308, 310 each independently include at least 20, 30,
40, 50, 60, 70, 80, or 90 percent by weight of the alloy of metal M
less than the first and second surface sections 302, 304,
respectively. In certain instances, the first and second body
sections 308, 310 each independently include less than 10, 5 or 1
percent by weight of the alloy of metal M.
[0036] The first and second surface sections 302, 304 may be
provided with a number of cooling channels 326. The cooling
channels 326 may be of any suitable shape in cross-section and may
be constructed of any suitable material. The cooling channels 326
may be provided as a single layer or multiple layers as needed. The
cooling channels 326 may be collectively connected to an inlet 328
and an outlet 330 for the transport of a cooling fluid, which is
optionally water.
[0037] The cooling channels 326 may be formed via machine drilling
so as to create openings in the form of channels. Drilling itself
can be both costly and labor intensive. An alternative may be to
form the channels via casting, wherein a liquid melt of a metallic
casting material is introduced into a cast preformed with cores,
the voids left behind later become the cooling channels.
[0038] Cores may generally be made from sand held together with a
binding agent. After the liquid metal solidifies the binding agent
breaks down and the crumbling sand may then be removed from the
holes, typically by shaking or sand blasting.
[0039] In these designs using sand cores, the length to diameter
ratio for making holes is typically about 5 to 1. This means that
cooling channels produced by cores may be too short and fat for
effective heat transfer. To create cast-in cooling passages that
can be used for effective heat transfer, a non-limiting way would
be to place ferrous alloy tubing in the mold and pour the copper
alloy around it.
[0040] In this casting process, using a copper-alloy containing
liquid melt in comparison to an all ferrous liquid melt provides a
synergistic benefit both in cost and performance. As all ferrous
metallic material would have the relatively high melting point, a
ferrous core would be very sensitive to the extreme heat required
and formed during an all ferrous liquid melt casting process and
may melt unfavorably. In this scenario, cooling channels may be
formed in an all ferrous die via the very labor intensive drilling
process and the casting may not be a viable option.
[0041] With the present invention in one or more embodiments,
copper-alloy has a substantially lowered melting point in
comparison to ferrous alloy; and as a result, ferrous cores may be
used in a cast with copper-alloy containing liquid melt in a
temperature that does not induce melting the cores. Accordingly,
cooling channels may be readily and relatively easily formed via
casting for the copper-alloy containing dies. In this way, not only
the copper-alloy containing dies provide relatively better cooling,
but also the cooling can be effected more economically as the
cooling channels can be formed more cost effectively. Simply put,
the present invention in one or more embodiments provides faster
and cheaper cooling all at the same time.
[0042] Ferrous alloy such as steel has one of the highest melting
points of all the commonly used metal alloys. Any metal gets very
soft and weak when it approaches it's melting point. Therefore
metal inserts in a mold can be melted or severely softened when
liquid steel enters the cavity. Steel melting point is at or around
2800.degree. F. while copper alloy melting point is at or around
1750.degree. F. If liquid copper is poured around ferrous alloy
tubing such as steel tubing, the steel tubing will stay solid and
in position. Pouring liquid steel around steel tubing puts the
tubes dangerously close to the melting point and they collapse
and/or distort as mentioned previously. The copper alloy for the
tool empowers the ability to cast-in cooling passages. To make a
cast steel die ideally tubing inserted into the mold should be made
out of something with a much higher melting point than steel,
however there are very few metals with melting points higher than
steel; mostly rare metals with no engineering significance.
[0043] Referring back to FIG. 4, and in an alternative view,
reference numerals 402, 404 collectively refer to a first surface
section of the first die portion 112 and a second surface section
of the second die portion 114, respectively. Reference numerals
408, 410 collectively refer to a first body section of the first
die portion 112 and a second body section of the second die portion
114, respectively. Reference numerals 430, 432, 434 refer to
relevant portion of the first body section 408 corresponding to the
binder 420, the binder 422, and the punch 424, respectively.
Reference numerals 440, 442, 444 refer to relevant portion of the
first surface section 402 corresponding to the binder 420, the
binder 422, and the punch 424, respectively.
[0044] FIG. 4 illustratively depicts a partial cross-section of a
variation to the system referenced in FIG. 3A. As illustratively
depicted in FIG. 4, the first die portion 112 may include binders
(a.k.a. blank-holders) 420, 422 and a punch 424 spaced apart from
both the binders 420, 422. This is particular to a draw/die
operation where the binders 420, 422, by coming closer to the
second die part 114, provide a reasonably good positioning of the
metallic part 118 as located within the cavity 122. Once the
metallic part 118 is positioned within the cavity 122 and flexibly
secured by the binders 420, 422 and the second die portion 114, the
punch 424 may then come into contact with the metallic part 118 to
impart the drawing. The term "flexibly secured" refers to the
operation that is particular to the draw/die operation, in which
the metallic part 118 is still movable through the area defined
between each of the binders 420, 422 and the second die portion
114, as may be needed to feed the metallic material into the area
defined between the punch 424 and the second die portion 114.
[0045] FIG. 3A and FIG. 4 both illustratively depict that the first
and second die portions 112, 114 include surface sections and body
sections. In the alternative (not shown), the first and second die
portions may be constructed entirely of the material forming the
surface sections. Because the material forming the surface sections
tend to be relatively more costly, the practicality of the first
and second die portions 112, 114 made entirely out of the material
forming the surface sections may be limited by cost consideration.
However, as mentioned herein elsewhere, the increased cost in
building such die portions may be mitigated by a reduction in cost
for forming the cooling channels. Therefore, such design is
believed to still be useful relative some existing designs where
die portions are constructed entirely of ferrous alloys.
[0046] FIG. 5A illustratively depicts a variation of the
cross-section referenced in FIG. 3A or FIG. 4, with FIG. 5B showing
a cross-section taken along lines 5B-5B. A notable difference in
FIG. 5A with comparison to FIG. 3A or FIG. 4 lies in the shape and
construction of cooling channels 526, which are configured in
"wafer" style. Cooling liquid may be provided via a bottom surface
of the second die part 114 and flows through each of the cooling
channels and returns back out via an outlet (not shown).
[0047] In one or more embodiments, the disclosed invention as set
forth herein overcomes the challenges faced by known production of
metallic articles. However, one skilled in the art will readily
recognize from such discussion, and from the accompanying drawings
and claims that various changes, modifications and variations can
be made therein without departing from the true spirit and fair
scope of the invention as defined by the following claims.
* * * * *