U.S. patent application number 10/736557 was filed with the patent office on 2005-06-23 for die casting method system and die cast product.
Invention is credited to Barnes, Chuck, Hollacher, Robert, Seaver, Sean.
Application Number | 20050133187 10/736557 |
Document ID | / |
Family ID | 34677212 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050133187 |
Kind Code |
A1 |
Seaver, Sean ; et
al. |
June 23, 2005 |
Die casting method system and die cast product
Abstract
An embodiment in accordance with the present invention provides
a method for the production of castings with incorporated tubes,
where the castings are from cast metal and where the tubes are
cast-in with a superheated molten metal. Multiple tubes or a
plurality of designs may be incorporated into the invention. The
present invention also provides a method for cooling the interior
of a cast product before, during, and after the product is
cast.
Inventors: |
Seaver, Sean; (Plainwell,
MI) ; Hollacher, Robert; (St. Joseph, MI) ;
Barnes, Chuck; (Kalamazoo, MI) |
Correspondence
Address: |
BAKER & HOSTETLER LLP
Washington Square, Suite 1100
1050 Connecticut Avenue, N.W.
WASHINGTON
DC
20036
US
|
Family ID: |
34677212 |
Appl. No.: |
10/736557 |
Filed: |
December 17, 2003 |
Current U.S.
Class: |
164/98 ; 164/100;
164/900 |
Current CPC
Class: |
B22D 17/007 20130101;
B22D 19/0072 20130101 |
Class at
Publication: |
164/098 ;
164/100; 164/900 |
International
Class: |
B22D 019/04; B22D
023/00; B22D 025/00 |
Claims
1. A method for production of a casting incorporating a passage
comprising: disposing at least one tube in a mold to form the
passage; and casting a metal around the tube, wherein a portion of
the tube is deformed during casting.
2. The method according to claim 1, wherein the metal is a
semi-solid metal.
3. The method according to claim 1, wherein the tube comprises
steel.
4. The method according to claim 1, wherein the mold comprises
guides matching the direction of the tube through the casting.
5. The method according to claim 1, wherein the metal is an
aluminum alloy.
6. The method according to claim 1, wherein the portion of the tube
is crimped or clamped.
7. The method according to claim 1, further comprising treating at
least a portion of a surface of the tube.
8. The method according to claim 7, wherein the treating comprises
spraying the surface with an aluminum composition.
9. The method according to claim 7, wherein the treating comprises
shot blasting.
10. The method according to claim 7, wherein the treating
comprising metal plating.
11. The method according to claim 1, further comprising passing
fluids through the tube before, during, or after casting.
12. A means for production of a casting incorporating a passage
comprising: disposing means that places at least one tube in a
mold; and a casting means that casts a metal around the tube.
13. The casting means according to claim 12, wherein the metal is a
semi-solid metal.
14. The casting means according to claim 12, wherein the tube
comprises steel.
15. The casting means according to claim 12, wherein the mold
comprises guides matching the direction of the tube through the
casting.
16. The casting means according to claim 12, wherein the metal is
an aluminum alloy.
17. The casting means according to claim 12, wherein the tube is
crimped or clamped.
18. The casting means according to claim 12, further comprising
treating at least a portion of a surface the tube.
19. The casting means according to claim 18, wherein the treating
comprises spraying the surface with an aluminum composition.
20. The casting means according to claim 18, wherein the treating
comprises shot blasting.
21. The casting means according to claim 18, wherein the treating
comprising metal plating.
22. A cast product, comprising: at least one tube; and metal cast
around the tube.
23. The method according to claim 1, wherein the tube comprises
aluminum.
24. The method according to claim 1, wherein the metal is a liquid
metal.
25. The method of claim 1, wherein the casting is hollow.
26. The method of claim 1, wherein the mold comprises openings to
pass a cooling medium through the casting.
27. The method of claim 1, wherein the casting is steel or
aluminum.
28. A method for production of a casting incorporating a passage
comprising: disposing a tube in a mold to form the passage, the
tube having a first end and a second end; closing the tube at the
first or second end; deforming a portion of the tube during
casting; and casting a metal around the tube to form a product.
29. The method according to claim 28, wherein the second end is
closed during casting and is opened after casting by a metal
treatment.
30. The method according to claim 28, wherein a cooling medium is
disposed in the tube.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to die casting. More
particularly, the present invention relates to the casting of
components having internal passages.
BACKGROUND OF THE INVENTION
[0002] In many applications, die cast products involving internal
passages are necessary. These passages are typically for fluids,
such as for example, water, oils, and gases, and are generally
introduced by machining the passages into the product after it has
been cast.
[0003] However, where after-cast machining is currently used, such
processing can add significant cost to the final product. In other
cases, the complex fluid flow patterns that are most desired are
often difficult, costly, or impossible to achieve using current
machining methodology.
[0004] Accordingly, it is desirable to provide a method and system
to introduce passages into a die cast product before or during the
casting of the product itself.
SUMMARY OF THE INVENTION
[0005] The foregoing needs are met, to an extent, by the present
invention, wherein in one embodiment of the present invention a
method for production of a casting incorporating a passage is
provided comprising disposing at least one tube in a mold and
casting a metal around the tube. The metal may be molten or
semi-solid metal and comprise aluminum and aluminum alloys. The
tubes of the invention may also comprise any metal, including, but
not limited to, steel, and be crimped or clamped in some
embodiments.
[0006] The outer surface of the tubes can be treated prior to
casting. Such treatments include spraying the surface with an
aluminum composition, shot blasting, and/or metal plating. In some
embodiments of the present invention, fluids may be passed through
the cast-in tubes before, during, and after casting. Molds of the
present invention may comprise passages that match the direction of
the tube through the casting.
[0007] In accordance with another embodiment of the present
invention a system for production of a casting incorporating a
passage is provided comprising a disposing means that places at
least one tube in a mold and a casting means that casts a metal
around the tube. The metal may be molten or semi-solid metal and
comprise aluminum and aluminum alloys. The tubes of the invention
may also comprise any metal, including, but not limited to, steel,
and be crimped or clamped in some embodiments.
[0008] The outer surface of the tubes can be treated prior to
casting. Such treatments include spraying the surface with an
aluminum composition, shot blasting, and/or metal plating. In some
embodiments of the present invention, fluids may be passed through
the cast-in tubes before, during, and after casting. Molds of the
present invention may comprise passages that match the direction of
the tube through the casting.
[0009] Another embodiment of the invention provides a cast product
having at least one tube and metal cast around the tube.
[0010] There has thus been outlined, rather broadly, certain
embodiments of the invention in order that the detailed description
thereof herein may be better understood, and in order that the
present contribution to the art may be better appreciated. There
are, of course, additional embodiments of the invention that will
be described below and which will form the subject matter of the
claims appended hereto.
[0011] In this respect, before explaining at least one embodiment
of the invention in detail, it is to be understood that the
invention is not limited in its application to the details of
construction and to the arrangements of the components set forth in
the following description or illustrated in the drawings. The
invention is capable of embodiments in addition to those described
and of being practiced and carried out in various ways. Also, it is
to be understood that the phraseology and terminology employed
herein, as well as the abstract, are for the purpose of description
and should not be regarded as limiting.
[0012] As such, those skilled in the art will appreciate that the
conception upon which this disclosure is based may readily be
utilized as a basis for the designing of other structures, methods
and systems for carrying out the several purposes of the present
invention. It is important, therefore, that the claims be regarded
as including such equivalent constructions insofar as they do not
depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a diagrammatic representation of a tube and mold,
designed with passages to hold the tube.
[0014] FIG. 2 is a cross-sectional view taken along the 2-2 in FIG.
1.
[0015] FIG. 3 is a diagrammatic representation of an alternate tube
design and mold, also designed with a passage to accommodate the
tube.
[0016] FIG. 4 is a cross-sectional view taken from the 4-4 in FIG.
3.
[0017] FIG. 5 is a diagrammatic representation of a tube design
that crosses over itself.
[0018] FIG. 6 is a diagrammatic representation of two tubes that
comprise an intersection.
DETAILED DESCRIPTION
[0019] The invention will now be described with reference to the
drawing figures, in which like reference numerals refer to like
parts throughout. An embodiment in accordance with the present
invention provides a method for the production of castings with
incorporated passages, where the castings are from cast metal and
where tubes are cast-in with a superheated molten metal to form the
passages.
[0020] The cast metal may be any metal including, but not limited
to steel, zinc, magnesium, or combinations thereof. In some
embodiments, aluminum and aluminum alloys are cast. Aluminum alloys
include 357 alloy, 380 alloy, ADC12 alloy, 356.2 alloy, and other
aluminum-silicon alloys.
[0021] A variety of presses and die cast methods may be used with
the present invention. For example, squeeze casting, gravity
casting, and high and low pressure die casting methods may all be
used. In some embodiments, vertical die cast presses may also be
used. Vertical die cast presses manufactured by THT Presses
preferred in some applications are disclosed in U.S. Pat. Nos.
5,660,223 and 5,429,175, assigned to and commercially available
from THT Presses, Inc., Dayton, Ohio. THT presses of this invention
may be classified as "indexing-type" or "shuttle-type." Though the
indexing press will be detailed in an embodiment below, both types
of presses may be used in the instant invention.
[0022] The THT presses, such as a 200 Ton Indexing Shot Machine, a
1000 Ton Shuttle Machine, or a 100 Ton Shuttle Machine, in
particular, are capable of operating at a higher speed and with a
shorter cycle time than previously known die casting presses and
which, as a result, produce higher quality parts with reduced
porosity. The die casting presses are also simpler and less
expensive in construction, requiring less maintenance and therefore
more convenient to service.
[0023] The casting methods of the present invention need not be
limited to die casting methods of molten metal. In fact, in some
embodiments, semi-solid metal (SSM) casting may be preferred. SSM
casting is defined broadly herein to encompass any casting
technique whereby the metal introduced into a die cavity is greater
than 20% granular (i.e., solids). SSM casting techniques that are
known in the art include, but are not limited to, rheocasting and
thixocasting.
[0024] SSM casting may be preferred in some embodiments of the
present invention because it is performed at lower temperatures
where often 20% -70% of the metal is granular and thus in a slurry,
rather than liquid state. The cooler temperatures can extend the
useful life of the dies. Moreover, the slurry state of the metal
reduces turbulence within the metal flow as it is introduced into
the die, so as to reduce the incorporation of air and gas into the
metal as it is being cast. Thus, porosity and quality control
complications are reduced.
[0025] In one embodiment, vertical die cast presses are used with
SSM casting techniques. In other words, SSM is cast using a
vertical die casting apparatus. Specifically, the indexing time
(i.e., the delay between indexing between the pour station 80 and
transfer station 85) can be used to control the time the molten
metal is cooled in the shot sleeve to reach the SSM range. That is,
the amount of time the metal spends in the shot sleeve before it is
injected into the molds can be regulated or optimized for a
desirable microstructure. Alternatively, molten metal at a
predetermined temperature may be poured into the shot sleeve of
shuttle presses, i.e. presses that lack the indexing feature.
[0026] The shear forces present in SSM casting may be more suitable
to the present invention in some embodiments over traditional
molten metal casting methods. In such an event, larger tubes
ranging from about 0.25 inches to about 0.37 inches in outer
diameter may be incorporated into the cast-in tube castings than
otherwise possible.
[0027] Many metals and alloys known in the art can be used for SSM
casting and can be employed with the instant invention. In some
embodiments aluminum-silicon alloys can be used. By definition,
aluminum alloys with up to but less than about 11.7 weight percent
Si are defined "hypoeutectic", whereas those with greater than
about 11.7 weight percent Si are defined "hypereutectic". In all
instances, the term "about" has been incorporated in this
disclosure to account for the inherent inaccuracies associated with
measuring chemical weights and measurements known and present in
the art. In yet other embodiments, aluminum-silicon copper alloys
and/or aluminum-copper alloys may be used with the present
invention.
[0028] Tubes that may be cast-in in the present invention may
comprise any metal, preferably steel or hydraulic tubing in some
embodiments. The steel tubes can have a composition with less than
about 0.17 weight percent carbon, less than about 0.35 weight
percent silicon, less than about 0.04 weight percent sulfur, less
than about 0.04 weight percent phosphorus and between about
0.40-0.80 weight percent manganese. Preferably, the tubes are free
from surface defects, blow holes and cracks.
[0029] Tubes of the present invention can be of varying wall
thickness. Where deformation of the tube is not desirable, the wall
thickness and composition is preferably strong enough to withstand
pressures of 6,000 psi to 20,000 psi and more preferably, pressures
of 8,000 psi to 12,000 psi. For steel tubes, the corresponding wall
thickness may range from about 0.02 inches to about 0.04 inches,
but a wider range may also be acceptable.
[0030] Referring now to FIGS. 1 and 2 there is shown a die 1 into
which a guide 2 has been cut. The guide 2 can be cut to fit the
path of a tube 3 which is to be embedded into the metal cast. The
tube 3 may of any design or path. For example, the tube 3 may have
one opening on one face of the mold or cast and then another
opening on another face of the mold or cast as shown in FIG. 1.
However, in some embodiments, tube 3 may have and opening on one
face and then be tapered, crimped, or clamped at the other end such
that fluids become trapped inside the cast as shown in FIGS. 3 and
4. Alternatively, tubes may have paths that cross over (FIG. 5) or
intersect (FIG. 6). All such configurations and others are within
the scope of the present invention.
[0031] In addition, more than one tube may be incorporated into a
cast-in tube mold or product. All such tubes should be accounted
for in the design of the mold such that guide 2 may be cut into
each half of the mold to accommodate the tube or tubes.
[0032] The tubes 3 may optionally be machined at one or more
openings 4. For example, threading for screws or bolts may be
inserted. In other embodiments, the outer surface of the tubes may
be coated with a thin surface layer to reduce the likelihood of
tube movement (such as slipping or rolling) within the cast
product. Coatings may include, such as, for example, alumina and
aluminum oxide, and may be sprayed on or plated. The thickness of
such coating applications will be apparent to one of ordinary skill
in the art. Other treatments to the outer surface of the tubes can
include shot blasting or grating.
[0033] Referring back to FIG. 1, once a tube design and
accompanying mold are selected, the tube 3 is generally located by
gravity in the mold 1 by predetermined guide 2 in the lower half of
the mold. The tubes are then secondarily located and secured using
a reverse passages in the upper half of the mold such that the tube
is secured and crimped or clamped in place.
[0034] Where SSM casting is desired, preferably, the metal is be
cast is heated in a range from about 10.degree. C. to about
15.degree. C. above the liquidus temperature (i.e., the semi-solid
temperature). For Al--Si alloys this generally ranges from about
585.degree. C. to about 590.degree. C. The melt temperature is then
allowed to cool to form a semi-solid slurry before it is finally
cast.
[0035] In some applications, the mold 1 and tube 3 design is such
that, optionally, a cooling medium can be passed through the tubing
before, during, and/or after the casting process is taking place.
In such an embodiment, couplers may be added to the open end of the
tube allow for entry of fluids for cooling. The couplers could then
be removed, machined, or sheared from the final cast product. This
procedure may enhance internal casting cooling rates and thus,
cycle times. Also, internal cooling has the potential to improve
the metallurgical properties and/or casting integrity of the final
cast product. Alternatively, improved tube bonding with the cast is
possible.
[0036] The many features and advantages of the invention are
apparent from the detailed specification, and thus, it is intended
by the appended claims to cover all such features and advantages of
the invention which fall within the true spirit and scope of the
invention. Further, since numerous modifications and variations
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation
illustrated and described, and accordingly, all suitable
modifications and equivalents may be resorted to, falling within
the scope of the invention.
* * * * *