FILLER METAL WITH FLUX FOR BRAZING AND SOLDERING AND METHOD OF MAKING AND USING SAME

Abstract

A wire (10) for use in a brazing or soldering operation has an elongated body (12) of a metallic material. The elongated body (12) has an outer surface (18). A channel (14) is formed along a length of the body. The channel (14) has an opening (A.sub.1). A flux solution (22) is deposited within the channel (14) and along the length of the body. The flux solution (22) covers a portion of the outer surface (18). A portion of the flux solution (22) is exposed through the opening (A.sub.1) in the channel (14).

Claims

1-20. (canceled)

21. A wire for brazing and soldering comprising: an elongated body of a brazing material, the elongated body having a central axis; a plurality of channels formed along the elongated body, each channel having an opening that is transverse to the central axis of the elongated body, each channel is only partially filled with a flux solution to a height below an imaginary plane spanning across the channel opening, wherein the imaginary plane is aligned with uppermost points forming the opening.

22. The wire of claim 21 formed into an annular ring.

23. The wire of claim 22 wherein each of the channel openings is along an inner circumference of the annular ring.

24. The wire of claim 22 wherein a first portion of the channel openings of the plurality of channels is along an inner circumference of the annular ring and a second portion of the channel openings of the plurality of channels is along an outer circumference of the annular ring.

25. The wire of claim 21 wherein the flux solution comprises a flux material and binder material.

26. The wire of claim 25 wherein the binder material is a polymer-base material.

27. The wire of claim 26 wherein the polymer-base material comprises a polymer selected from a group consisting of an acrylic polymer and a polymer produced from copolymerization of carbon dioxide.

28. The wire of claim 26 wherein the polymer is a poly alkylene carbonate.

29. The wire of claim 26 wherein the flux material is aluminum-based.

30. The wire of claim 26 wherein the flux material is cesium-based.

31. The wire of claim 21 wherein the brazing material of the elongated body is an aluminum alloy.

32. The wire of claim 21 wherein the brazing material of the elongated body is a zinc/aluminum alloy comprising at least having at least 2 percent by weight aluminum.

34. The wire of claim 21 wherein a surface of the flux solution in each channel is exposed through the opening in each channel.

35. The wire of claim 22 wherein the ring includes ten channels.

36. The wire of claim 21 wherein the flux solution includes a surface having an outwardly concave shape.

37. The wire of claim 21 wherein the elongated body has a generally circular cross-sectional shape between each of the plurality of channels.

38. A wire for brazing and soldering comprising: an elongated body of a brazing material, the elongated body having a central axis; a plurality of channels formed along the elongated body, each channel having an opening that is transverse to the central axis of the elongated body, each channel is only partially filled with a flux solution to a height below an imaginary plane spanning across the channel opening, wherein the imaginary plane is aligned with uppermost points forming the opening, and wherein each channel of the plurality of channels is spaced from an adjacent channel by a separating portion of the elongated body and wherein each channel extends about 10% to 50% of a height of a separating portion.

39. The wire of claim 38 formed into an annular ring wherein each of the channel openings is along an inner circumference of the annular ring.

40. The wire of claim 38 formed into an annular ring wherein a first portion of the channel openings of the plurality of channels is along an inner circumference of the annular ring and a second portion of the channel openings of the plurality of channels is along an outer circumference of the annular ring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which:

[0043] FIG. 1 is a cross-sectional view taken transverse to the length of a first braze wire of the present invention;

[0044] FIG. 2 is a cross-sectional view taken transverse to the length of a second braze wire of the present invention;

[0045] FIG. 3 is a cross-sectional view taken transverse to the length of a third braze wire of the present invention;

[0046] FIG. 4 is a cross-sectional view taken transverse to the length of a fourth braze wire of the present invention;

[0047] FIG. 5 is a perspective view of a lengthwise section of a typical braze wire of the present invention;

[0048] FIG. 6 is a perspective view of a wire of the present invention formed into an annular ring;

[0049] FIG. 7 is a cross-sectional view of the annular ring of FIG. 6;

[0050] FIG. 8 is a perspective view of a lengthwise section of a typical braze wire of the present invention;

[0051] FIG. 9 is a top view of the braze wire of FIG. 8 formed in the form of an annular ring;

[0052] FIG. 10 is a schematic view of a manufacturing method of forming a wire of the present invention;

[0053] FIG. 11 is a partial cross-sectional view of a pair of work rolls for rolling a channel into an elongated wire;

[0054] FIG. 12 is a perspective view of a flux solution chamber and a die/wiper for removing excess flux solution on a wire pf the present invention;

[0055] FIG. 13 is a cross-sectional view of a method for joining a pair of tubular members using a wire of the present invention formed as an annular ring; and

[0056] FIG. 14 is a cross-sectional view of an alternative embodiment of the braze wire of the present invention.

DETAILED DESCRIPTION

[0057] While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.

[0058] The present invention is directed to a brazing/soldering wire for use in multiple metal combinations including aluminum applications. The end use for these materials is typically industrial applications, such as automobiles and automobile component manufacturing as well as other heat transfer applications including air conditioning and refrigeration manufacture. Of course, other applications can be had as well. The brazing/soldering wire of the present invention may be used on many different materials including aluminum alloys, zinc alloys, copper alloys and silver alloys, etc. The wire itself can be produced from an aluminum alloy, a silver alloy, a copper alloy, and/or a zinc alloy.

[0059] The Wire

[0060] The present invention includes a solid wire 10 rather than a narrow sheet or strip that is preferably very robust and will not move when assembled onto component parts. This is important because in air conditioning applications, braze wire is commonly supplied in ring-form. The rings are friction fit or snuggly placed around tubes. Because current ring shaped braze wires often lose their grip on component parts, causing the rings to shift or fall off altogether, rings formed from the wire 10 of the present invention are specifically constructed so as to be less likely to plastically deform by the friction fit about the component parts. As a result, they are less likely to shift or fall off prior to the brazing or soldering process. This important aspect of the present invention is described in more detail below.

[0061] Referring to FIGS. 1 though 5, a wire 10 having an elongated body 12 with a channel 14 reformed along a length of an outer surface 18 is illustrated. The wire 10 is formed from a metallic material supplied at a diameter of about 0.031 inches to 0.125 inches (0.787 mm to 3.18 mm), preferably 0.079 inches to 0.090 inches (2.00 mm to 2.29 mm), or any range or combination of ranges therein. The wire 10 has been rolled or reformed to a new geometric shape, such as substantially rectangular or elliptical configuration having a major axis D.sub.1 of about 0.105 inches (2.67 mm) and a minor axis C.sub.1 of about 0.048 inches (1.22 mm). The overall shape of the reformed wire 10 may also be described as kidney-shaped, U-shaped, or C-shaped in cross-section. A discontinuity 20 in the outer surface 18 and, thus the shape of the wire 10, is caused by the channel 14 formed therein. It would be appreciated by one of ordinary skill in the art that dimensions of the wire 10 may vary greatly based on customer requirements.

[0062] The channel 14 typically has a substantially rectangular or conic section shape having an opening A.sub.1 parallel to a central axis 19 of the wire 10 of about 0.030 inches (0.76 mm) and a depth B.sub.1 of about 0.020 inches (0.51 mm). Preferably, the opening A.sub.1 is about 30% to 70% of the starting diameter of the wire or a major axis of the reformed wire, and the channel 14 has a depth B.sub.1, about 10% to 50% of the starting diameter of the wire or a major axis of the reformed wire. Again, it would be appreciated by one of ordinary skill in the art that dimensions of the channel 14 may vary greatly based on customer requirements.

[0063] The channel 14 is at least partially filled with a volume of flux solution 22. The volume of flux solution 22 per length of the wire 10 is determined by the end use for the wire. However, it is preferable for the entire volume of flux solution 22 to be positioned within the channel 14 and for the flux solution to be exposed through the opening in the channel 14. Thus, the remaining portions of the outer surface 18 of the wire are free of flux solution 22. A top surface of the flux solution 22 is preferably located below an imaginary line or plane 24 spanning the uppermost surface of the opening A.sub.1 of the channel 14. (See FIG. 3).

[0064] The flux solution 22 preferably comprises a polymer-based binder combined with a flux material. Because the flux solution 22 includes a polymer-based binder, the wire 10 may be manipulated into virtually any shape without disturbing the flux solution 22. Thus, the wire 10 of the present invention may be provided on spools, coils, straight rods and most importantly made to order custom performs, such as rings and the like. The wire 10 may further be supplied in unlimited wire sizes with different flux formulations as well as different alloy/flux ratios.

[0065] Referring to FIGS. 6-7, a wire 10 of the present invention has been formed into a pre-form. The pre-form may be a rod, slug, or any other custom shape. In the embodiment illustrated the pre-form is an annular ring 30. The ring 30 is formed such that the channel 14 bearing the flux solution 22 forms an inner wall 32 of the ring 30. An outer wall 34 of the ring 30 is free of flux solution 22. By locating the flux/polymer solution 22 on the inner wall of the ring 30, two advantages are realized. First, the flux, within the flux solution 22, is located adjacent one of the parts to be joined. Second, the flux solution 22 is in compression, rather than tension, wherein the solution 22 tends to remain within the channel 14 rather than flaking, pealing, or otherwise falling off of the wire 10.

[0066] Further to the structure of the inner wall of the ring 30, the imaginary straight line or plane 24, of which the top surface of the flux solution 22 is preferably below, is located entirely along the inner wall 32 of the ring 30. Thus, the opening A.sub.1 of the channel 14 is also located entirely along the inner wall 32 of the ring 30. In other words, the flux solution 22 forms a portion of the inner wall 32. More particularly, the top surface of the flux solution 22 forms at least a portion of the inner wall 32.

[0067] Referring to FIG. 8, an alternative embodiment of a wire 10 of the present invention is illustrated. In this embodiment, a plurality of channels 14 are formed in the wire 10. The channels 14 are formed along a transverse length of the elongated body 12, such that openings are transverse to the central axis 19 of the wire 10. In other words, the length of the wire 10 forming the channel 14 is transverse to the elongated body 12 of the wire 10. Each channel 14 is otherwise as described above, each channel 14 being at least partially filled with a flux solution 22, preferably filled to a height below the imaginary line or plane 24. The shapes and dimensions of the wire 10 are, likewise, as described above.

[0068] FIG. 9 is an illustration of the wire 20 of FIG. 8 reformed to an annular ring 30. The ring 30 is formed such that the channel 14 bearing the flux solution 22 forms an inner wall 32 of the ring 30. In this example, the outer wall 34 of the ring 30 includes a section or portion of each channel 14 and thus the flux solution 22 within each channel 22 also forms a portion of the outer wall 34 of the ring 30. This configuration achieves the advantages of the previous embodiment as well as the additional benefit that upon melting or liquefying, the flux in the flux solution 22 is free to flow from each channel 14 in a direction transverse to the length of the elongated body 12. It would be appreciated by one of ordinary skill in the art that the channels 14 may be completely contained along the inner wall 32 of the ring, similar to the single channel 14 of the FIGS. 6-7, or that some percentage of the channels 14 may be completely contained along the inner wall 32 of the ring 34 with some percentage of the channels 14 forming a portion of both the inner and outer walls 32,34 of the ring. It would be still further appreciated by one of ordinary skill that some percentage of the channels 14 may be completely contained on the inner wall 32, that some percentage of the channels 14 may be completely contained on the outer wall 34, and that some percentage of the channels 14 may form a portions of the inner and outer wall 32,34 of the ring 30. In other words, the channels 14 may be distributed about the circumference of the outer surface 18 of the elongated body 12.

[0069] Now referring specifically to FIG. 14, another alternative embodiment of the wire 10 of the present invention is illustrated. The dimensions of the wire 10 of this embodiment are the same or similar to the dimensions previously discussed. This wire 10 includes a plurality of channels, preferably two. Accordingly, the wire has an elongated body 12 which includes at least two channels 14a,14b located lengthwise along the outer surface 18 of the wire 10. These channels 14a,14b are separated by a portion of the outer surface 18 and are preferably located on opposing sides of the wire 10. Thus, the channels 14a,14b may be spaced 180 degrees apart and may spiral about the outer surface 18.

[0070] Each channel 14a,14b forms a separate discontinuity 20a, 20b in the outer surface 18 and has a base 40 joining a pair of opposing sidewalls 44a,44b. The discontinuities 20a,20b alter the outer surface 18 and, thus the shape of the wire 10. It would be appreciated by one of ordinary skill in the art that dimensions of the wire 10 may vary greatly based on customer requirements. Furthermore, the channels 14a,14b may have disparate volumes or may have equal volumes depending on end use requirements, and/or the volume of flux required. In other words, the ratio of the flux to the wire volume may be varied from channel to channel. Moreover, the chemistry of the flux in one channel may be varied comparatively to the chemistry of the flux in a second channel.

[0071] The base 40 is generally planar as illustrated but may be curved or bowed, either convexly or concavely or some combination thereof. The sidewalls 44a,44b angle radially outwardly from the base 40 such that the sidewalls 44a,44b form angles .sub.a,.sub.b,.sub.c,.sub.d with the base 40. The angles .sub.a,.sub.b,.sub.c,.sub.d may be less than, equal to, or greater than 90 degrees. Preferably, the angles .sub.a,.sub.b,.sub.c,.sub.d are greater than 90 degrees; more preferably, the angles .sub.a,.sub.b,.sub.c,.sub.d are between 90 and 150 degrees; and most preferably, the angles .sub.a,.sub.b,.sub.c,.sub.d are between 90 and 120 degrees; the angles .sub.a,.sub.b,.sub.c,.sub.d may be any range or combination of ranges therein, collectively (all equal) or individually (disparate values or some combination of equal and unequal values).

[0072] The channels 14a14b are at least partially filled with separate volumes of flux solution 22a,22b. The volume of flux solution 22a,22b per length of the wire 10 is determined by the end use for the wire 10. However, it is preferable for the entire volume of flux solution 22a,22b to be positioned within the channels 14a,14b and for the flux solution to be exposed through the opening in the channel 14. Thus, the remaining portions of the outer surface 18 of the wire 10 are free of flux solution 22. A top surface of the flux solution 22a,22b may be located above, below, or co-planar with the an imaginary line or plane spanning the uppermost surface of the opening A.sub.1,A.sub.2 of each channel 14a,14b. Of course, the separate top surfaces of the flux solution 22a,22b in the first and second channels 14a,14b respectively, may have different heights as shown in FIG. 14.

[0073] There are several advantages of the wires of the present invention. For example, the raw material is cheaper and the process speed is significantly faster than any other product combining wire and flux. As compared to the Omni product, the wires 10 of the present invention include a flux solution which is exposed along a length of the wire 10. The flux solution 22 is not encased. As a result, this allows the flux within the flux solution 22 to melt and release from the wire prior to the alloy of the wire melting.

[0074] The Flux Solution

[0075] The flux solution 22 is preferably prepared in the following manner. A granulated or beaded polymer is first dissolved in a solvent to form a liquefied suspension. The polymeric material may be derived from an acrylic polymer, such as a proprietary acrylic polymer manufactured by S.A. Day Mfg. Co. The polymeric material, however, is preferably derived from a carbon dioxide rather than a petroleum; it is enzyme degradable; and it is biocompatible where thermal decomposition yields a carbonate which vaporizes for complete removal, leaving minimal ash residue. The products of combustion are non-toxic (primarily carbon dioxide and water). Accordingly, the polymer is generally a thermoplastic, preferably a copolymer, more preferably a poly alkylene carbonate produced through the copolymerization of CO.sub.2 with one or more epoxides.

[0076] Once the polymer is dissolved in the solvent, a flux is then added in powder form. Any suitable flux, corrosive and non-corrosive, can be used depending on the desired end use. The resulting solution is a thick, homogeneous mixture having a paste-like consistency similar to caulk.

[0077] The Method of Manufacture

[0078] As illustrated in FIGS. 10-12, the channel 14 (or channels 14a,14b) is formed by a roll forming operation. A rolling mill 100 having an upper roll 102 and a complementary lower roll 104 imparts a specific, pre-designed shape to the wire 10. The profile of the upper and lower rolls 102,104 is determined by the characteristics desired by the rolled wire, i.e. designed to accommodate a specific volume of flux required per length of wire or flux/wire metal ratio. In short, the profiles of the complementary rolls 102,104 form the wire's profile at the bite of the rolls 102,104, and the rolls 102,104 may be changed for different profiles desired.

[0079] As the wire 10 exits the rolling operation, the flux solution 22 (or flux solutions 22a,22b) is added to the channel 14. This is accomplished by inserting the flux solution 22 within a dispensing cartridge 108. An external source of pressure, shown schematically at reference number 112, forces the solution 22 from the cartridge 108 to a holding chamber or die chamber 116 wherein a bath of the solution 22 is generated within the chamber 116. The amount of flux solution 22 forced from the cartridge 108 to the chamber 116 is controlled by a metering device.

[0080] The reformed wire 10 enters the chamber 116 through an opening at one end of the chamber 116 so that the solution 22 coats the entire surface of the wire 10. The solution 22 also enters the channel 14 through the opening A.sub.1 and fills, or partially fills, the channel 14 on the wire's outer surface 18. The coated wire 10 then exits the chamber 116 through a rubber wiper or die 120 which includes a shaped opening or passageway 124. Excess solution 22 is wiped or cleaned as the wire 10 exits the chamber, leaving only the desired amount of flux solution 22 on the wire 10, preferably only within the channel 14. In other words, the die controls the amount of solution left within the channel 14, distributes the solution 22 evenly within the channel, and ensures no excess solution 22 remains on the wire 10.

[0081] Once the channel 14 is filled with the desired volume of solution 22, the solution is dried or cured to form a solid within the channel 14. Any number of methods may be used, including ultra-violet, infra-red, heated fluid pressure, etc. In this embodiment, electrodes 128a,128b are electrically connected to the coated wire 10 wherein an electric current from a source of power 132 heats the wire 10 to the desired temperature, generally between 100 F. to 250 F. (38 C. to 121 C.), preferably between 125 F. to 175 F. (52 C. to 79 C.), most preferably 150 F. (66 C.), or any range or combination of ranges therein.

[0082] Once the solution is sufficiently dried, the wire 10 is spooled for delivery or further process.

[0083] Method of Use

[0084] An example of the present invention is illustrated in FIG. 13. A first tubular metallic part 200 is to be joined to a second tubular metallic part 204. The first tubular part 200 is passed through a ring 30 formed of the finished wire, such as the annular ring 30 illustrated in FIGS. 6-7 and 9. The flux-laden channel 14 of the ring 30 is located adjacent an outer surface 202 of the first tubular part 200. The second tubular part 204 has a radially outwardly flared flange 208 to aid in guiding an end portion of the first tubular part 200 into the second tubular part 204. Unlike rings of the prior art, the flow of the flux from the ring 30 of the present invention is not restricted and flows freely upon heating so as to permit joining of the first and second tubular parts 200,204 once the alloy of ring 30 melts.

[0085] In a second example, the ring 30 described in conjunction with the previous example is an aluminum soft temper alloy such 4047 aluminum. The first and second tubular parts 200,204 are produced from aluminum or an aluminum alloy. The flux solution 22 is produced by dissolving QPAC polymer beads manufactured by Empower Materials Inc. in a methyl ethyl ketone (MEK) solvent. The flux is a non-corrosive aluminum flux such as the aluminum potassium fluoride NOCOLOK having a melting temperature of about 1049 F. to 1062 F. (565 C. to 572 C.) or flux B sold by S.A. Day Mfg. Co. containing potassium tetrafluoroaluminate and cesium tetrafluoroaluminate having a melting temperature of about 1055 F. (560 C.).

[0086] The MEK solvent is particularly useful. MEK solvent is highly evaporative so a low heat will cure the solution 22. Thus, the flux of this example can be liquefied and released from the flux solution 22 within the desired range of between 100 F. (38 C.) and 250 F. (121 C.), most preferably about 150 F. (66 C.), or any range or combination of ranges therein. These ranges will sufficiently evaporate the solvent without causing the remaining flux/polymer mix 22 to become brittle.

[0087] In a third example, the tubular parts 200,204 are of aluminum or an aluminum alloy having a melting temperature of about 1150 F. to 1200 F. (620 C. to 650 C.). The wire is produced from a zinc/aluminum alloy having a melting temperature of about 850 F. to 950 F. (454 C. to 510 C.), such as an alloy comprising at least about 2% aluminum, preferably about 65% to 85% zinc and 15% to 35% aluminum, and most preferably 78% zinc and 22% aluminum and having a melting temperature of about 900 F. (482 C.), or any range or combination of ranges therein. The channel 14 is filled with a polymer/flux blend 22 which activates at about 788 F. to 900 F. (420 C. to 482 C.), preferably a polymer as described above with a cesium-based flux in the amount of about 56% to 66% cesium, 27% to 32.2% fluorine, and 8.6% to 11.4% aluminum or about 6.4% silicon, or any range or combination of ranges therein. Most preferably, the flux solution 22 includes a cesium-based flux which has an activation temperature of about 865 F. (463 C.), such as those produced by Chemetall GmbH of Frankfurt, Germany.

[0088] While the specific embodiments have been illustrated and described, numerous modifications are possible without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying Claims.