Flux used for brazing aluminum-based alloy

• US 4,906,307 A
• Filed: 09/20/1988
• Issued: 03/06/1990
• Est. Priority Date: 10/16/1987
• Status: Expired due to Term

• Current Assignee: Calsonic Kansei Corporation
• Original Assignee: Calsonic Kansei Corporation
• Inventors: Fujiyoshi, Tatuya
• Primary Examiner(s): McDowell, Robert
• Application Number:
  US07/246,778
• Time in Patent Office: 532 Days
• Field of Search: 148/23, 148/25, 148/26, 228/223, 228/263.17
• US Class Current: 148/26
• CPC Class Codes: B23K 35/3605 Fluorides

Abstract

Fluxes for use in brazing aluminum-based alloy pieces are disclosed. One is a flux which comprises 70 to 90% wt % K₂ SiF₆ and 30 to 10 wt % AlF₃. The other is a flux which comprises 98.5 to 94 wt % base composition which includes K₂ SiF₆ whose amount is 70 to 90 wt % of the base composition and AlF₃ whose amount is 30 to 10 wt % of the base composition; 0.5 to 3 wt % LiF; and 1 to 3 wt % NaF. In order to facilitate the application of the flux to the pieces to be brazed, polybutene is used as a dispersing agent.

Claims

1. A flux for use in brazing aluminum-based alloy pieces, comprising:

70 to 90 wt % K₂ SIf₆ ; and

30 to 10 wt % AlF₃.

2. A flux as claimed in claim 1, in which said flux contains 85 wt % K₂ SiF₆, and 15 wt % AlF₃.

3. A flux for use in brazing aluminum-based alloy pieces, comprising:

98.5 to 94 wt % base composition, said base composition including K₂ SiF₆ whose amount is 70 to 90 wt % of the base composition and AlF₃ whose amount is 30 to 10 wt % of the base composition;

0.5 to 3 wt % LiF; and

1 to 3 wt % NaF.

4. A flux as claimed in claim 3, in which said base composition occupies 96 to 98.5 wt % of the flux, and in which said base composition including K₂ SiF₆ whose amount is 85 to 90 wt % of the base composition and AlF₃ whose amount is 15 to 10 wt % of the base composition;

in which said LiF occupies 0.5 to 2 wt % of the flux, and said NaF occupies 1.0 to 3.0 wt % of the flux.

5. A method of brazing aluminum-based alloy pieces, comprising by steps:

(a) preparing a flux which comprises 70 to 90 wt % K₂ SiF₆ and 30 to 10 wt % AlF₃ ;

(b) uniformly dispersing said flux in a polybutene to provide a suspension, said polybutene being a copolymer containing isobutylene as a major part and having at its terminal end a double bond and represented by the following formula;

##STR3## (c) applying said suspension to portions which are to be brazed and brazing said pieces.

6. A method of brazing aluminum-based alloy pieces, comprising by steps:

(a) preparing a flux which comprises 98.5 to 94 wt % base composition, said base composition including K₂ SiF₆ whose amount is 70 to 90 wt % of the base composition and AlF₃ whose amount is 30 to 10 wt % of the base composition;

0.5 to 3 wt % LiF; and

1 to 3 wt % NaF;

(b) uniformly dispersing said flux in a polybutene to provide a suspension, said polybutene being a copolymer containing isobutylene as a major part and having at its terminal end a double bond and represented by the following formula;

##STR4## (c) applying said suspension to outer surfaces of aluminum-based alloy pieces which are to be brazed and brazing said pieces.

7. A method of brazing aluminum-based alloy pieces, comprising by steps:

(a) preparing a flux which comprises 65.6 to 99.9 wt % KAlF₄ and 34.4 to 0.1 wt % K₃ AlF₆ ;

(b) uniformly dispersing said flux in a polybutene to provide a suspension, said polybutene being a copolymer containing isobutylene as a major part and having at its terminal end a double bond and represented by the following formula;

##STR5## (c) applying said suspension to outer surfaces of the aluminum-based alloy pieces which are to be brazed and brazing said pieces.

8. A flux for use in brazing aluminum-based alloy pieces, comprising:

98 to 90 wt % base composition, said base composition including potassium fluorosilicate whose amount is 30 to 90 wt % to said base composition and zinc fluoride whose amount is 70 to 10 wt % to the base composition;

1 to 3 wt % sodium fluoride; and

1 to 7 % aluminum fluoride.

9. A method of brazing aluminum-based alloy pieces, comprising by steps:

(a) preparing a flux which contains 98 to 90 wt % base composition, said base composition including potassium fluorosilicate whose amount is 30 to 90 wt % to said base composition and zinc fluoride whose amount is 70 to 10 wt % to the base composition;

1 to 3 wt % sodium fluoride; and

1 to 7 % aluminum fluoride;

(b) uniformly dispersing said flux in a polybutene to provide a suspension, said polybutene being a copolymer containing isobutylene as a major part and having at its terminal end a double bond and represented by the following formula;

##STR6## (c) applying said suspension to outer surfaces of aluminum-based alloy pieces which are to be brazed and brazing said pieces.