U.S. patent application number 11/853900 was filed with the patent office on 2008-04-24 for method of making precursor hollow castings for tube manufacture.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS, INC.. Invention is credited to K. Balasubramanian, Anil K. Sachdev.
Application Number | 20080096039 11/853900 |
Document ID | / |
Family ID | 39318298 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080096039 |
Kind Code |
A1 |
Sachdev; Anil K. ; et
al. |
April 24, 2008 |
Method of making precursor hollow castings for tube manufacture
Abstract
A tubular formation technique utilizing centrifugal casting
incorporating a moveable launder system to deliver molten alloy
along an extended length within a centrifugal caster to form a
hollow tubular precursor of extended length. The technique is
adaptable to all alloy systems but may be particularly suited for
so called "hard alloys" that are susceptible to substantial work
hardening or are difficult to extrude.
Inventors: |
Sachdev; Anil K.; (Rochester
Hills, MI) ; Balasubramanian; K.; (Hyderabad,
IN) |
Correspondence
Address: |
GENERAL MOTORS CORPORATION;LEGAL STAFF
MAIL CODE 482-C23-B21, P O BOX 300
DETROIT
MI
48265-3000
US
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS,
INC.
DETROIT
MI
|
Family ID: |
39318298 |
Appl. No.: |
11/853900 |
Filed: |
September 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60862056 |
Oct 19, 2006 |
|
|
|
Current U.S.
Class: |
428/586 ;
164/114; 164/286 |
Current CPC
Class: |
Y10T 428/12292 20150115;
B22D 13/107 20130101; B22D 13/023 20130101 |
Class at
Publication: |
428/586 ;
164/114; 164/286 |
International
Class: |
B22D 13/02 20060101
B22D013/02 |
Claims
1. A casting system comprising: a centrifugal caster having an
interior and a material acceptance opening; and an elongate
moveable launder adapted for insertion through the material
acceptance opening and into the interior of the caster for delivery
of molten metal to positions along the interior of the caster
spaced away from the material acceptance opening.
2. The casting system of claim 1, wherein the elongate moveable
launder is moveable in reciprocating relation relative to the
caster.
3. The casting system of claim 2, wherein the elongate moveable
launder is mounted on rails.
4. The casting system of claim 1, wherein the molten metal is
selected from at least one of the group consisting of: aluminum,
aluminum alloys, magnesium, magnesium alloys, titanium and titanium
alloys, copper and copper alloys, and refractory metals and their
alloys.
5. Billets formed by the casting system of claim 1.
6. The casting system of claim 1, further comprising a flow forming
apparatus adapted to process billets from the caster.
7. A method of centrifugally casting a tubular billet, the method
comprising the steps of: providing a centrifugal caster having an
interior and a material acceptance opening; providing an elongate
moveable launder adapted for reciprocating insertion and withdrawal
through the material acceptance opening and into the interior of
the caster for delivery of molten metal to positions along the
interior of the caster spaced away from the material acceptance
opening; inserting a distal portion of the launder into the
interior of the caster; delivering a quantity of molten metal along
the launder from a position outside the caster to the interior of
the caster for deposit at locations spaced away from the material
acceptance opening; and expelling hollow substantially tubular
billets from the caster.
8. The method as recited in claim 7, wherein the molten metal is
deposited as the launder is moved in reciprocating relation to the
caster such that the molten metal is deposited in layers along the
length of the caster, and where the individual layers can be a
different metal or alloy.
9. The method as recited in claim 7, wherein the elongate moveable
launder is mounted on rails.
10. The method as recited in claim 7, wherein the molten metal is
selected from at least one of the group consisting of: aluminum,
aluminum alloys, magnesium, magnesium alloys, titanium and titanium
alloys, copper and copper alloys, and refractory metals and their
alloys.
11. A method of centrifugally casting and flow forming a tubular
billet, the method comprising the steps of: providing a centrifugal
caster having an interior and a material acceptance opening;
providing an elongate moveable launder adapted for reciprocating
insertion and withdrawal through the material acceptance opening
and into the interior of the caster for delivery of molten metal to
positions along the interior of the caster spaced away from the
material acceptance opening; inserting a distal portion of the
launder into the interior of the caster; delivering a quantity of
molten metal along the launder from a position outside the caster
to the interior of the caster for deposit at locations spaced away
from the material acceptance opening; expelling hollow
substantially tubular billets from the caster; and delivering the
tubular billets to a wall thinning flow forming apparatus adapted
to process the billets from the caster.
12. The method as recited in claim 11, wherein the molten metal is
deposited as the launder is moved in reciprocating relation to the
caster such that the molten metal is deposited in layers along the
length of the caster, and where the individual layers can be a
different metal or alloy.
13. The method as recited in claim 11, wherein the elongate
moveable launder is mounted on rails.
14. The method as recited in claim 11, wherein the molten metal is
selected from at least one of the group consisting of: aluminum,
aluminum alloys, magnesium, magnesium alloys, titanium and titanium
alloys, copper and copper alloys, and refractory metals and their
alloys.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of and priority from U.S.
Provisional Application 60/862,056 filed Oct. 19, 2006 the contents
of which are hereby incorporated by reference in their
entirety.
TECHNICAL FIELD
[0002] The present invention relates generally to the field of
hollow tube manufacture and more particularly to the field of
centrifugal casting of elongate hollow tube precursors adaptable
for flow forming or other treatments.
BACKGROUND OF THE INVENTION
[0003] It is well known to form tubes from materials such as
aluminum and magnesium using extrusion techniques or seam welding
rolled sheet stock. Tubes of such materials may also be formed by
drawing a hollow blank over a mandrel or flow forming an extrusion
formed precursor over a mandrel. While such techniques for forming
tubes may be suitable for many materials, they may be difficult to
apply to alloys such as high ductility aluminum alloys that exhibit
substantial work hardening or to magnesium alloys that do not
exhibit good hot deformation behavior unless extremely low
extrusion speeds are utilized. Alloys that are characterized by
substantial amounts of work hardening may be desirable to
accommodate deformation strain during fabrication of complex
shapes, or in the case of magnesium alloys for light weight.
SUMMARY OF THE INVENTION
[0004] The present invention provides advantages and alternatives
over prior practices by providing tubular formation techniques that
are particularly suited for so called "hard alloys" that are
susceptible to substantial work hardening or are difficult to
extrude.
[0005] According to one aspect, a process is provided utilizing
centrifugal casting incorporating a moveable launder system to
deliver molten alloy along an extended length within a centrifugal
caster to form a hollow tubular precursor of extended length.
[0006] According to another aspect, a process is provided utilizing
centrifugal casting incorporating a moveable launder system to
deliver layers of alloy and/or composite material along an extended
length within a centrifugal caster to form a hollow tubular
precursor of extended length.
[0007] According to still another aspect, a process is provided
wherein a centrifugal caster incorporating a moveable launder
system delivering molten alloy along an extended length within the
caster is mated with a flow forming procedure to yield a tube of
desired thickness formed from a work hardenable alloy or from
alloys that are difficult to hot work by standard methods like
extrusion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The following drawings which are incorporated in and which
constitute a part of this specification illustrate exemplary
practices in accordance with the present invention and, together
with the general description above and the detailed description set
forth below, serve to explain the principals of the invention
wherein:
[0009] FIG. 1 is a view illustrating a casting system incorporating
a retractable elongate launder in inserted relation within a
centrifugal caster;
[0010] FIG. 2 is a view similar to FIG. 1 with the launder
retracted towards the mouth of the caster;
[0011] FIG. 3A is a side view of cast billets of tubular
construction formed by the system illustrated in FIGS. 1 and 2;
[0012] FIG. 3B is an end view of cast billets of tubular
construction formed by the system illustrated in FIGS. 1 and 2;
and
[0013] FIG. 4 is a schematic view of a tube flow forming operation
that may be paired with a casting system as illustrated in FIGS. 1
and 2.
[0014] While embodiments of the invention have been illustrated and
generally described above and will hereinafter be described in
connection with certain potentially preferred procedures and
practices, it is to be understood and appreciated that in no event
is the invention to be limited to such embodiments and procedures
as may be illustrated and described herein. On the contrary, it is
intended that coverage shall extend to all alternatives and
modifications as may embrace the broad principals of the invention
within the true spirit and scope thereof.
DETAILED DESCRIPTION
[0015] Reference will now be made to the various drawings wherein
like elements are designated by like reference numerals throughout
the various views. As illustrated, in accordance with the present
invention a centrifugal caster 10 is mated with a moveable launder
20. The launder 20 preferably includes a proximal reservoir portion
22 for acceptance of a molten alloy and a distal insertion portion
24 of reduced hemispherical cross section for insertion an extended
length into the caster 10.
[0016] As shown, the launder 20 may be mounted on a carriage
assembly 30 for reciprocating movement in axial relation to the
caster 10. While the carriage assembly 30 is illustrated as a cart
mounted on rails, it is likewise contemplated that virtually any
supporting structure adapted to translate reciprocal movement to
the launder may be used.
[0017] In operation the insertion portion 24 of the launder 20 may
be projected through a mouth opening of the caster 10 a
predetermined length along the interior of the caster. While the
insertion portion 24 is within the caster 10, a molten alloy may be
delivered to the reservoir portion 22 thereby causing the alloy to
flow along the insertion portion for deposit at the interior of the
caster 10. As will be appreciated, the moveable nature of the
launder 20 permits the location of alloy deposit to be moved
inwardly away from the mouth of the caster. Moreover, the alloy can
be deposited progressively along the length of the caster 10 by
inserting or withdrawing the insertion portion 24 while the alloy
is being delivered. Moreover, by use of controlled reciprocation,
layers of similar or dissimilar material may be deposited at the
interior of the caster 10 so as to form layers within the final
cast billets. While the process may be used with substantially any
metal system, it is contemplated that the system may be
particularly useful for aluminum, aluminum alloys, magnesium,
magnesium alloys, titanium and titanium alloys, copper and copper
alloys, and refractory metals and their alloys.
[0018] By use of the reciprocating launder system it has been found
that it may be possible to increase the thickness of billets formed
within the caster 10 and/or to cast alloys that may not be suitable
for centrifugal casting or for casting into standard extrusion
billets. By way of example only, it has been found that tubes of
high ductility aluminum alloys may be formed with substantial wall
thickness on the order of about 10 mm or greater. Benefits are also
believed to be applicable to alloys of materials such as magnesium
and titanium that are characterized by limited extrudability.
[0019] It is also contemplated that billets cast using the
reciprocating launder system may be more amenable to subsequent
tubular flow forming resulting in a lengthened and thinned
structure. By way of example only and not limitation, a
representative flow forming process is illustrated in FIG. 4. As
shown, in this process a centrifugal casting 50 engages a chuck 52
with a support tool 54 held at the interior of the casting 50. As
the casting 50 is rotated, and the support tool 54 may or may not
be rotated, the casting 50 engages a spinning forming tool 56 which
causes the walls of the casting to be thinned and elongated.
[0020] It is to be understood that while the present invention has
been illustrated and described in relation to potentially preferred
embodiments, constructions, and procedures, that such embodiments,
constructions, and procedures are illustrative only and that the
invention is in no event to be limited thereto. Rather, it is
contemplated that modifications and variations embodying the
principals of the invention will no doubt occur to those of skill
in the art. It is therefore contemplated and intended that the
present invention shall extend to all such modifications and
variations as may incorporate the broad aspects of the invention
within the true spirit and scope thereof.
* * * * *