U.S. patent number RE42,329 [Application Number 11/639,356] was granted by the patent office on 2011-05-10 for flux cored preforms for brazing.
This patent grant is currently assigned to Lucas-Milhaupt, Inc.. Invention is credited to Alan Belohlav, Charles E. Fuerstenau.
United States Patent |
RE42,329 |
Fuerstenau , et al. |
May 10, 2011 |
**Please see images for:
( Certificate of Correction ) ** |
Flux cored preforms for brazing
Abstract
A wire preform suitable for use in brazing components to one
another. The preform is made from a length of wire having a core of
flux material, and a longitudinal seam or gap that extends over the
length of the wire. The seam is formed so that when heated, the
flux material flows from the core and out of the seam. The length
of wire is in the form of a loop having a certain circumference so
that when the preform is heated, the flux material disperses
uniformly from the circumference of the preform for evenly treating
the surface of a component on which the preform is placed. The
length of wire may include a silver alloy.
Inventors: |
Fuerstenau; Charles E.
(Germantown, WI), Belohlav; Alan (Belgium, WI) |
Assignee: |
Lucas-Milhaupt, Inc. (Cudahy,
WI)
|
Family
ID: |
33489073 |
Appl.
No.: |
11/639,356 |
Filed: |
December 14, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
10202148 |
Jul 24, 2002 |
06830632 |
Dec 14, 2004 |
|
|
Current U.S.
Class: |
148/23;
148/24 |
Current CPC
Class: |
B23K
35/3006 (20130101); B23K 35/0227 (20130101); B23K
35/0216 (20130101); B23K 35/0266 (20130101); B23K
35/02 (20130101); B23K 35/406 (20130101); B23K
35/30 (20130101) |
Current International
Class: |
B23K
35/34 (20060101) |
Field of
Search: |
;219/137WM
;148/23,24 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1303605 |
|
Jun 1992 |
|
CA |
|
78 12546 |
|
Nov 1977 |
|
FR |
|
1180735 |
|
Feb 1970 |
|
GB |
|
63040697 |
|
Feb 1988 |
|
JP |
|
63303694 |
|
Dec 1988 |
|
JP |
|
01066093 |
|
Mar 1989 |
|
JP |
|
WO99/00444 |
|
Jan 1999 |
|
WO |
|
WO00/39172 |
|
Jul 2000 |
|
WO |
|
WO00/52228 |
|
Sep 2000 |
|
WO |
|
WO00/64626 |
|
Nov 2000 |
|
WO |
|
WO2002/000569 |
|
Jan 2002 |
|
WO |
|
WO00/31023 |
|
Apr 2002 |
|
WO |
|
WO03/068447 |
|
Aug 2003 |
|
WO |
|
WO03/089176 |
|
Oct 2003 |
|
WO |
|
Other References
International Search Report dated Dec. 21, 2007; PCT/US06/043856
filed Nov. 9, 2006. cited by other .
Written Opinion of the ISA dated May 10, 2008; PCT/US06/043856
filed Nov. 9, 2006. cited by other .
International Preliminary Report on Patentability dated May 14,
2008; PCT/US06/043856 filed Nov. 9, 2006. cited by other .
International Search Report dated Dec. 4, 2008; PCT/US08/064871
filed May 27, 2008. cited by other .
Written Opinion of the ISA dated Nov. 25, 2009; PCT/US08/064871
filed May 27, 2008. cited by other .
International Preliminary Report dated Dec. 1, 2009;
PCT/US08/064871 filed May 27, 2008. cited by other .
International Search Report dated Apr. 9, 2008; PCT/US07/025309
filed Dec. 11, 2007. cited by other .
Written Opinion of the ISA dated Jun. 11, 2009; PCT/US07/025309
filed Dec. 11, 2007. cited by other .
International Preliminary Report dated Jun. 11, 2009;
PCT/US07/025309 filed Dec. 11, 2007. cited by other .
Belova, "Understanding Brazing Fundamentals," The American Welder;
Sep.-Oct. 2000; Jul. 11, 2008;
<http://www.aws.org/wj/amwelder/9-00/fundamentals.html>.
cited by other .
International Search Report dated Nov. 8, 2007; PCT/US07/069636
filed May 24, 2007. cited by other .
Written Opinion of the ISA dated Nov. 8, 2007; PCT;US07/069636
filed May 24, 2007. cited by other .
International Preliminary Report dated Nov. 28, 2008;
PCT;US07/069636 filed May 24, 2007. cited by other.
|
Primary Examiner: Lee; Emily M.
Assistant Examiner: Zhu; Weiping
Attorney, Agent or Firm: Boyle Fredrickson, S.C.
Claims
We claim:
1. A wire .[.preform.]. suitable for use in .[.brazing.].
.Iadd.joining .Iaddend.components to one another, comprising: a
length of wire having a core of a flux material, and a longitudinal
seam .[.or gap.]. extending over the length of the wire wherein the
seam is formed so that when heated, the flux material flows from
the core and out of the seam of the wire; and the length of wire is
in .[.the.]. .Iadd.a .Iaddend.form .[.of a loop having a certain
circumference.]. so that when .[.the preform is.]. heated, flux
material is dispersed uniformly .[.from the circumference of the
preform.]. .Iadd.therefrom .Iaddend.for evenly treating a component
.[.surface on which the preform is disposed.]. .
2. A wire .[.preform.]. according to claim 1, wherein the length of
wire is formed from an elongate metal sheet, and the seam of the
wire is defined by an inner edge portion of the sheet and a
confronting outer edge portion of the sheet.
3. A wire .[.preform.]. according to claim 2, wherein the inner
edge portion of the metal sheet is angled to be embedded in the
flux material.
4. A wire .[.preform.]. according to claim 1, wherein the seam on
the length of wire is on .[.the.]. .Iadd.an .Iaddend.inner
circumference of .[.the.]. .Iadd.a ring .Iaddend.preform.
5. A wire .[.preform.]. according to claim 1, wherein the length of
wire is .Iadd.preformed in a .Iaddend.helical .[.in form.].
.Iadd.shape.Iaddend..
6. A wire .[.preform.]. according to claim 5, wherein the seam
.Iadd.is .Iaddend.on .[.the.]. .Iadd.a .Iaddend.circumference of
the preform.
7. A wire .[.preform.]. according to claim 1, wherein the wire has
a diameter of between about 0.031 inch and .Iadd.about
.Iaddend.0.125 inch.
8. A wire .[.preform.]. according to claim 1, wherein the length of
wire comprises a silver alloy.
.Iadd.9. The wire of claim 1, wherein the wire includes: a rolled
metal alloy sheet that defines an encasing perimeter that extends
around the flux material of the core; an inner angled edge portion
of the sheet is embedded in the flux material and emerges from the
core and the sheet to extend around the flux material; and an outer
edge portion of the sheet confronts the sheet proximate a location
where the inner angled edge portion of the sheet emerges from the
core, thereby forming a seam..Iaddend.
.Iadd.10. A wire according to claim 1, wherein the length of wire
is in the form of a loop having a certain circumference to aid in
dispersion of flux material from an inner circumference of the loop
during brazing..Iaddend.
.Iadd.11. The wire of claim 10, wherein a laser aids with wire and
flux formation..Iaddend.
.Iadd.12. The wire of claim 1, wherein the wire may be at least one
of: an oval, a square, a multi-form helical loop; a braze ring; a
helical shape having a circular cross-section; and a wire having a
diameter between about 0.031 and about 0.125 inches..Iaddend.
.Iadd.13. The wire of claim 1, wherein when the wire reaches a
brazing temperature between approximately 500 and approximately
1100 degrees F., flux is dispersed from the seam uniformly along a
circumference of the wire..Iaddend.
.Iadd.14. The wire of claim 1, wherein the length of wire is formed
from a metal alloy sheet is formed into a U-shaped channel by a
die; the U-shaped channel is then passed through a trough by
pulling the metal alloy sheet in a direction away from a dispensing
apparatus; wherein the flux material is a powdered flux material
conveyed from a dispenser to fill the U-shaped channel; the filled
channel is passed out of the trough and through a die where the
filled channel begins to close; the metal alloy then passes through
a die where the channel is closed and a butt seam is formed with
opposing side edge portions of the channel; a path for the flux
material is created in a center of the core to aid in release of
the flux material from the core; the metal alloy then passes
through another die where the metal alloy is formed to its final
size diameter, while maintaining the path..Iaddend.
.Iadd.15. The wire of claim 14, wherein the wire is then packaged
in spools..Iaddend.
.Iadd.16. The wire of claim 1, wherein the metal alloy sheet is an
alloy of at least one of the following: aluminum-silicone;
zinc-aluminum; copper zinc; silver-copper-zinc;
silver-copper-zinc-tin; silver-copper-zinc-tin-nickel;
silver-copper-zinc-nickel; silver-copper-tin;
silver-copper-zinc-manganese-nickel; silver-copper-zinc-cadmium;
and silver-copper-zinc-cadmium..Iaddend.
.Iadd.17. The wire of claim 14, wherein the metal alloy sheet is a
narrow elongate strip coiled onto a spool to facilitate feeding of
the metal alloy during a manufacturing process..Iaddend.
.Iadd.18. The wire of claim 1, wherein the wire is formed into a
brazing wire having a size and a cross section of a desired shape
and adopting a configuration that is complementary to various
angles and sizes of surfaces to be brazed..Iaddend.
.Iadd.19. A brazing wire suitable for use in joining components to
one another by brazing, comprising: a length of wire having a core
of a flux material, and a longitudinal seam extending over the
length of the wire wherein the seam is formed so that when the wire
is heated, the flux material flows from the core and out of the
seam of the wire and is dispersed uniformly therefrom for evenly
treating components to be joined..Iaddend.
.Iadd.20. A wire suitable for use in joining components to one
another by brazing, comprising: a length of wire having a core of a
flux material surrounded by a metal sheet, and a longitudinal seam
extending along the length of the wire; an inner angled edge
portion of the sheet embedded in the flux material; and an outer
edge portion of the sheet confronting the inner angled portion of
the sheet proximate a location where the inner angled edge portion
of the sheet emerges from the core; wherein the length of wire is
in a form so that the seam is at an inner surface to aid in
dispersion of flux material from the inner surface during heating;
wherein when the wire is heated, the flux material becomes molten
and flows from the core and out of the seam of the wire; wherein
the molten flux material treats components in preparation for
brazing..Iaddend.
Description
FIELD OF THE INVENTION
.Iadd.Notice: More than one reissue application has been filed for
the reissue of U.S. Pat. No. 6,830,632. The reissue applications
are application Ser. Nos. 11/639,356 (the present application) and
12/834,506, which is a divisional application of U.S. application
Ser. No. 11/639,356..Iaddend.
The present invention is directed to wire preforms for use in
brazing.
DISCUSSION OF THE KNOWN ART
The brazing process typically involves joining ferrous and
non-ferrous metal components together by positioning a brazing
composition (such as an aluminum or silver-bearing metal alloy) and
a flux adjacent to or between surfaces of the components to be
joined, also known as the faying surfaces. To form the joint, the
metal alloy and flux and the faying surfaces are heated to a
temperature typically above the melting temperature of the alloy
but below the melting temperature of the components to be joined.
The alloy then melts, flows into the faying surfaces by capillary
action and forms a seal that bonds the faying surfaces to one
another.
A flux composition is often applied to the faying surfaces prior to
brazing. In one application, a flux can be selected so that, when
applied, it does one or more of the following: (1) removes oxides
ordinarily present on the faying surfaces; (2) promotes the flow of
the molten brazing alloy when heated to a temperature above its
melting point; and (3) inhibits further oxide formation on the
faying surfaces.
Flux cored wire ring preforms for brazing are known to have been
made using an aluminum/silicon metal alloy. When heated, the alloy
tends to men quickly enough to allow the core flux material to
disperse fairly evenly and to enable satisfactory joints to be
made. A known supplier of flux cored aluminum rin preforms is Omni
Technologies Corporation.
Initial attempts to make silver alloy flux cored braze ring
preforms using the same design principles as the aluminum preforms
met with little initial success, however. Specifically, when the
silver preforms were heated, the flux would not disperse evenly
about the rings but, rather, would exit only from opposite ends of
the silver wire forming the preforms before melting of the wire
itself. As a result the braze joints were poor.
Accordingly, there is a need for a flux cored braze ring preform
that, during heating, will disperse its core flux material evenly
about the ring and onto a surface to be treated for brazing. In
particular there is a need for such preforms made of silver
alloys.
SUMMARY OF THE INVENTION
The present invention is directed to a flux cored brazing preform.
A metal alloy is provided as an elongated thin sheet that is rolled
around its long axis so as to encase a flux material. The rolled
metal alloy sheet thus forms a flux cored wire having a
longitudinal seam through which the flux material, when in a molten
state, can exit.
The flux cored wire is then shaped into a braze ring preform which
when heated allows the encased flux material to flow uniformly from
the seam about the circumference of the preform, and to disperse
evenly for treating a surface to be brazed.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawing:
FIG. 1 is a flow chart depicting a method of producing lengths of
seamed brazing wire for shaping into brazing preforms according to
the invention;
FIG. 2 is a cross sectional view of the brazing wire produced
according to FIG. 1; and
FIGS. 3 to 5 show brazing preforms according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
In general, seamed flux cored brazing wires can be produced in
accordance with procedures disclosed in French Patent Application
no. 78 12546, published Nov. 25, 1977, and the seam area of the
rolled sheet of metal may be modified as described herein. Other
seamed flux cored brazing or welding wires are disclosed in, for
example, U.S. Pat. No. 3,935,414 (Jan. 27, 1976); U.S. Pat. No.
1,629,748 (May 24, 19271); U.S. Pat. No. 4,379,811 (Apr. 12, 1983);
U.S. Pat. No. 2,958,941 (Nov. 8, 1960); U.S. Pat. No. 4,396,822
(Aug. 2, 1983); U.S. Pat. No. 3,642,998 (Nov. 24, 1970); and
Japanese Patent No. 63-303694 (Dec. 1, 1988).
As represented in FIG. 1, a narrow elongate strip of a metal alloy
which may have been coiled onto a spool to facilitate the feeding
thereof during the manufacturing process is formed into a U-shape
channel by a first die. The U-shaped channel is passed through a
trough by pulling the strip in a direction away from the spool or
other dispensing apparatus. A powdered flux material is conveyed
from a dispenser so as to drop from the dispenser into a trough
which contains the U-shaped channel and to overfill the trough. A
vibrating apparatus is typically employed to vibrate the trough in
order to fill the strip. Optionally, lasers may be employed to
ensure that the amount of flux that fills the metal alloy strip is
sufficient to form an adequate brazed joint. The filled strip is
passed out of the trough, though a second die where the filled
channel begins to close. The wire then passes through a third die
where the wire is closed and a butt seam is formed with the
opposing side edge portions of the strip.
The wire then passes through a fourth die which forces an edge
portion of the seam inward, e.g., about 0.005'' to 0.010''. This
portion is maintained to about 45 degrees or less of the
circumference of the wire, and leaves a gap between the opposed
edge portions of strip. The inner edge portion extends toward the
center of the cored wire, and the space between the edge portions
contains flux. See FIG. 2, It is believed that this creates a path
for the flux in the center of the core to release from the
core.
The wire then passes through a fifth die where the wire is formed
to its final size diameter, while maintaining the seam as described
above. The flux cored wire is then packaged on spools and other
suitable packaging systems.
The metal alloy strip can be any of the following alloys, among
others: aluminum-silicone; zinc-aluminum; copper zinc;
silver-copper-zinc; silver-copper-zinc-tin; silver
copper-zinc-tin-nickel; silver-copper-zinc-nickel;
silver-copper-tin; silver-copper-zinc-manganese-nickel;
silver-copper-zinc-cadmium; and silver-copper-zinc-cadmium and
nickel.
The flux-cored brazing wire formed as described above can
subsequently be formed to into brazing preforms having any desired
shape, such as a circle or oval. The preforms can then be placed
between or adjacent to faying surfaces of components to be joined.
The preforms and the faying surfaces are then heated to a suitable
brazing temperature sufficient to melt the flux and the brazing
alloy and, thus, bond the faying surfaces. The components are then
cooled to solidify the brazing alloy and to secure the bond between
the faying surfaces.
As shown in cross section in FIG. 2, the flux cored wire 10
includes the rolled metal alloy sheet 12 that defines an encasing
perimeter that extends around the flux material 14 of the core. An
inner angled edge portion 16 of the sheet 12 is embedded in the
flux material 14. Moving counterclockwise in FIG. 2, the inner
angled edge portion 16 of the sheet 12 emerges from the core and
the sheet 12 extends around the flux material, and an outer edge
portion 18 of the sheet 12 confronts the sheet 12 in the vicinity
of the location where inner angled edge portion 16 of the sheet 12
emerges from the core, thereby forming a seam 20. Between the inner
angled edge portion 16 and the outer edge portion of the sheet.
There is a gap 22, in which a portion of the flux material 14
resides. Also, the inner angle edge portion 16 is surrounded by
flux material
The metal alloy strip 12 may be formed or bowed into a brazing wire
having a cross section of any desired shape and size. For example,
the strip 12 may be rolled about its longitudinal axis in a
substantially circular manner to form the wire 10 in FIG. 2. Once
rolled, a length of the wire may be shaped, twisted or molded into
various shapes, for example, adopting a configuration that is
complementary to the various angles and sizes of the surfaces to be
brazed. In specific embodiments, as illustrated in FIGS. 3 to 5,
the wire can be formed into braze rings or helical loops having a
circular cross-section, and further having a wire diameter between
about 0.031 and 0.125 inches.
As mentioned, the seamed, flux cored brazing wire 10 may be
manufactured by other techniques that are known in the art. For
example, roll forming technology, alone and in combination with
dies, can be employed to produce a cored wire. The cored wires may
also be produced with a gap to allow flux dispersion from the
seam.
Cored wire with a butt seam may also be produced, and due to other
factors (like an oval, square or other shape of preforms made from
the wire) the flux will be allowed to escape from the seam during
brazing.
FIGS. 3 to 5 demonstrate flux distribution along the seam of
flux-coated wire preforms made according to the invention. A copper
coupon 40 is held in place by a clamping device 42 and suspended in
the horizontal position. A flux-cored ring (preform 44 made from a
length of seamed flux cored wire) is set upon the top surface of
the copper coupon 40. Heat (from a propane, butane or similar
torch) is applied to the bottom of the coupon.
When the flux-cored preform 44 reaches a temperature between 500
and 1100.degree. F., flux can be seen dispersing from the wire seam
uniformly along the full circumference of the preform 44 as shown
in FIG. 4. Note the metal alloy strip is still in solid form, but
the flux is being uniformly dispensed from the seam around the
entire ring preform.
FIG. 5 shows a multi-turn helical loop preform 50 according to the
invention, wherein the coupon 40 and the preform 50 are heated
sufficient to cause molten flux material to disperse uniformly from
a seam along the inner circumference of the preform, and the evenly
over the top surface of the coupon 40.
While there have been described what are at present considered to
be the preferred embodiments of this invention, it will be obvious
to those skilled in the art that various changes and modifications
may be made thin without departing from the true spirit and scope
of the invention defined by the following claims.
* * * * *
References