Method of brazing an aluminum material
First Claim
1. A method of brazing an aluminum material which comprises:
- a chemical conversion coating step of bringing at least a brazing desired part of the aluminum material into contact with a treating solution containing potassium and fluorine ions to form a brazing flux layer composed of potassium pentafluoroaluminate on the surface of said aluminum material; and
a brazing step of heating at least the flux layer formed part to a temperature of lower than the melting point of the aluminum material and higher than the melting point of a brazing alloy to join said aluminum material to a counterpart material with said brazing alloy.
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Abstract
In a method of brazing aluminum material, the flux is formed on the surface of the aluminum material by a chemical conversion coating step. The aluminum material is brought into contact with a treating solution containing potassium and fluorine ions to cause a chemical reaction between aluminum components and potassium and fluorine ions, thereby forming K2 AlF5. The K2 AlF5 is present on the surface of the aluminum material as a uniform coating and acts as the flux during brazing. With the treating solution further containing zinc, the flux of K2 AlF5 and a pitting corrosion inhibiting layer of metallic zinc are simultaneously formed. The treating solution may further include powdered K2 AlF5 or AlF3 to increase the amount of flux and thus to intensify the action of the flux. The chemical conversion coating may be applied either to the material to be brazed or to the material for brazing.
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Citations
32 Claims
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1. A method of brazing an aluminum material which comprises:
- a chemical conversion coating step of bringing at least a brazing desired part of the aluminum material into contact with a treating solution containing potassium and fluorine ions to form a brazing flux layer composed of potassium pentafluoroaluminate on the surface of said aluminum material; and
a brazing step of heating at least the flux layer formed part to a temperature of lower than the melting point of the aluminum material and higher than the melting point of a brazing alloy to join said aluminum material to a counterpart material with said brazing alloy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
- a chemical conversion coating step of bringing at least a brazing desired part of the aluminum material into contact with a treating solution containing potassium and fluorine ions to form a brazing flux layer composed of potassium pentafluoroaluminate on the surface of said aluminum material; and
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20. The method of brazing an aluminum material which comprises:
- a chemical conversion coating step of bringing an aluminum brazing alloy into contact with a treating solution containing potassium and fluorine ions to form a flux layer composed of K2 AlF5 on the surface of said brazing alloy; and
a brazing step of supplying the brazing alloy subjected to said chemical conversion coating step to a brazing desired part of the aluminum material and heating to a temperature of higher than the melting point of the brazing alloy and lower than the melting point of the aluminum material to braze said aluminum material to a counterpart material. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
- a chemical conversion coating step of bringing an aluminum brazing alloy into contact with a treating solution containing potassium and fluorine ions to form a flux layer composed of K2 AlF5 on the surface of said brazing alloy; and
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30. A method of brazing an aluminum material which comprises:
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(a) contacting at least part of the aluminum material with a treating solution which forms a brazing flux layer of potassium pentafluoroaluminate on the part so contacted, and (b) heating said part to a temperature which is lower than the melting point of the aluminum material and higher than the melting point of a brazing alloy used to join said aluminum material to a counterpart material. - View Dependent Claims (31)
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32. In a method of brazing an aluminum material with a brazing flux, the improvement wherein the brazing flux is substantially composed of potassium pentafluoroaluminate.
Specification