Braze product including additive particles and methods of brazing
Additive particles are introduced to a braze joint by combining the additive particles with a flux and using the flux with additive particles to form a core or coating of a braze product including braze alloy and flux. Additive particles are selected to provide some improvement to the finished braze joint that cannot be achieved by combining the additive particles directly into the braze alloy. Methods of brazing include application of vibration to a braze joint while the braze joint is maintained at a brazing temperature. Vibration applied to the materials being joined is transmitted through the flux, molten braze alloy and additive particles, producing a braze joint of increased strength and uniformity.
1 . A wire, rod, sheet or preform for brazing, said wire, rod, sheet, or preform comprising:
a braze filler metal formed into a body of the wire, rod, sheet, or preform and having a channel, cavity, core, or coating, said braze filler metal having a first melting temperature;
brazing flux disposed in the channel, cavity, core, or coating, said brazing flux having a second melting temperature; and
additive particles comprising metal particles evenly distributed in the brazing flux, said metal particles having a particle size between 1 and 200 microns,
wherein the metal particles are present in a proportion of between .5% and 8% of the braze filler metal by weight, said metal particles released from the channel, cavity, core, or coating when the brazing flux is melted at the second melting temperature and said metal particles are soluble in the braze filler metal when the braze filler metal has melted at said first melting temperature, and at least some of said metal particles having a size greater than 20 microns remain partially undissolved after a brazing operation.
2 . The wire, rod, sheet, or preform for brazing of claim 1 , wherein the additive particles are metal particles having a third melting temperature greater than said first melting temperature.
3 . The wire, rod, sheet, or preform for brazing of claim 1 , wherein said additive particles are metal particles consisting of an elemental metal having a third melting temperature at least 100° C. greater than said first melting temperature.
4 . The wire, rod, sheet, or preform for brazing of claim 2 , wherein said metal particles have an average diameter between 13 and 17 microns, with a maximum diameter of 45 microns.
5 . The wire, rod, sheet, or preform for brazing of claim 1 , wherein the additive particles have a first size range and a second size range, the size of metal particles in the second size range being from 2 to 40 times the size of metal particles in the first size range.
6 . The wire, rod, sheet, or preform for brazing of claim 5 , wherein the first size range is between 1 micron and 10 microns and the second size range is between 20 microns and 40 microns.
7 . The wire, rod, sheet, or preform for brazing of claim 1 , wherein the body of the wire or rod is formed from an elongate strip of filler metal having longitudinal edges, the elongate strip formed to surround the brazing flux and additive particles, with the longitudinal edges of the elongate sheet adjacent each other.
8 . The wire, rod, sheet, or preform for brazing of claim 2 , wherein the metal particles are soluble in the filler metal when the filler metal has melted, the metal particles having a first size range between 1 and 10 microns dissolving into the molten filler metal at a first time after the wire, rod, sheet, or preform is heated to said first melting temperature, and the metal particles in a second size range between 20 and 40 microns dissolving into the molten filler metal at a second time after the wire, rod, sheet, or preform is heated to said first melting temperature, said second time being greater than said first time.
9 . The wire, rod, sheet or preform for brazing of claim 4 , wherein the metal particles are nickel particles and the braze filler metal comprises between 20% and 30% Cu by weight.
10 . The wire, rod, sheet or preform for brazing of claim 4 , wherein the braze filler metal comprises between 40% and 50% Ag, between 20% and 30% Cu and less than 5% Ni by weight and the metal particles are nickel particles.
11 . The wire, rod, sheet or preform for brazing of claim 4 , wherein the metal particles are nickel or nickel alloy particles and the combined total of nickel in the braze filler metal and metal additive particles does not exceed 10% of the braze filler metal by weight.
12 . The wire, rod, sheet or preform for brazing of claim 1 , wherein the metal additive particles have complete solid solubility in at least one metal present in the braze filler metal.
13 . The wire, rod, sheet or preform for brazing of claim 12 , wherein the metal additive particles are nickel or nickel alloy and the braze filler metal includes between 20% and 30% copper by weight.
14 . The wire, rod, sheet or preform for brazing of claim 12 , wherein the metal additive particles have solid solubility with iron.