Brazing material with continuous length layer of elastomer containing a flux

Abstract

A flux coated brazing material wherein the flux coating composition is suitable for continuously coating a continuous length of brazing material. Aspects include a flux coating composition for coating or coring a brazing material useful as a flux coating for preparing a continuous length brazing material according to the described method.

Description

[0001] This application claims the benefit of U.S. Provisional Application No. 60 / 735,323, filed Nov. 10, 2005, which is hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates generally to brazing material and brazing fluxes, and more specifically to flux-coated or flux-cored brazing material. [0004] 2. Related Art [0005] Various methods are known for joining metal components, including mechanical bonding, adhesive bonding, soldering, welding and brazing. Although brazing, soldering and welding are similar, there are important differences. Soldering is generally performed at lower temperatures (below 450° Celsius), but does not produce as strong a joint. Welding is a high-temperature process in which the two metals to be joined are actually melted and fused together. Brazing is a method of joining two pieces of metal together with a third, molten filler material. Welded and brazed joints are usually at least as str...

AI Technical Summary

Benefits of technology

"The present invention provides a flux-coated brazing material that is easy to use and can conform to the contours of many joining surfaces. The flux composition has elasticity to prevent cracking, peeling, chipping, fracturing or detachment when the brazing material is bent or conformed to the contours of a brazing joint. The flux composition also has suitable surface hardness and durability during transit, handling, storage, use and disposal. The brazing material can be coated or cored on a continuous length without requiring post-cure or baked hardening. The invention also provides a method for surface preparation of brazing material for coating or coring with a flux, a method for manufacturing a continuous length of flux-coated brazing material, and a method for brazing using a continuous length of flux-coated brazing material."

Problems solved by technology

Soldering is generally performed at lower temperatures (below 450° Celsius), but does not produce as strong a joint.

The removal of residual flux increases the overall product cost due to the additional cleaning steps and the cost to dispose waste resulting from the cleaning process.

A disadvantage of currently available flux-coated and flux-cored brazing rods or wires made in the above-described manner is that the fluxes are relatively brittle.

Thus, when known flux-coated or flux-cored brazing materials are curled, bent or deformed (e.g., during transit, storage, handling or use) the flux coating or flux core easily cracks, fractures, peels or chips so that it becomes a non-continuous flux and portions of the flux coating or flux core may detach from the rods or wires.

When the flux coating or flux core becomes detached and non-continuous, it loses its usefulness and effectiveness because it may produce a joint having less mechanical bond or strength.

A further disadvantage of known flux-coated and flux-cored brazing materials is that the brittle flux-coating or flux-core does not allow the brazing material to be coiled, spooled, wound or manufactured into rings or other form factors that may be formed from the flux cored or coated wire or rod into a substantially circular, oval or elliptical shapes.

When the brazing material is formed into a circular, oval or elliptical shape it causes the brittle flux coating or flux core to crack, peel, fracture (which permit moisture to enter the flux) and possibly detach from the brazing material.

Thus, the length of the rod or wire is limited to shorter lengths (generally less than 20 inches) and non-continuous forms that cannot be transported and handled in spooled, coiled, wound, rolled form or produced in other forms capable that permit the brazing material to be packaged, transported, stored or used in compact or compressed form.

Another disadvantage is that current flux coating processes only lend themselves to coating brazing material lengths less than or equal to approximately 20 inches, such as rods, due to the required post-cure step of baking the coating to cure or harden the flux—a step necessary to impart durability to the flux coating.

The currently available form of flux coated brazing materials is limited to a rod of approximately 20 inches or less, thus limiting the usefulness of the length and causing waste, as the last inch of the rod is generally discarded as being too small to effectively use.

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