US2002041822A1PendingUtilityA1

Aluminum filler alloy containing sodium for fluxless brazing

35
Priority: Jun 22, 2000Filed: Jun 21, 2001Published: Apr 11, 2002
Est. expiryJun 22, 2020(expired)· nominal 20-yr term from priority
Inventors:David L. Childree
B23K 2103/10B23K 35/286
35
PatentIndex Score
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Cited by
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References
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Claims

Abstract

An aluminum filler alloy, particularly useful in fluxless controlled atmosphere brazing (CAB), contains from about 4% to 20% wt. % silicon (Si) and about 0.0008% to 0.06% sodium (Na). In addition to the sodium, the alloy may also contain bismuth (Bi) and/or potassium (K) in the ranges of about 0.0005% to 0.03% K, and from about 0.03% to 0.133% Bi. The filler metals can be clad to aluminum core alloys preferably from the 3XXX, 5XXX, or 6XXX alloys series.

Claims

exact text as granted — not AI-modified
What is claimed is:  
     
         1 . A process for controlled atmosphere brazing comprising, 
 brazing an aluminum alloy without flux in a controlled atmosphere, using a filler alloy comprising, 
 a) 4-20 wt. % silicon;  
 b) 0.0008-0.06 wt. % sodium; and  
 c) the balance aluminum and incidental impurities.  
   
     
     
         2 . The process for controlled atmosphere brazing of  claim 1 , wherein said filler alloy comprises 0.005-0.05 wt. % sodium.  
     
     
         3 . The process for controlled atmosphere brazing of  claim 2 , wherein said filler alloy comprises 0.006-0.03 wt. % sodium.  
     
     
         4 . The process for controlled atmosphere brazing of  claim 1 , wherein said filler alloy further comprises at least one element selected from the group comprising 0.0005-0.03 wt. % potassium and 0.03-0.133 wt. % bismuth.  
     
     
         5 . The process for controlled atmosphere brazing of  claim 4 , wherein said filler alloy comprises both 0.0005-0.03 wt. % potassium and 0.03-0.133 wt. % bismuth.  
     
     
         6 . The process for controlled atmosphere brazing of  claim 4 , wherein said filler alloy comprises 0.005-0.05 wt. % sodium.  
     
     
         7 . The process for controlled atmosphere brazing of  claim 6 , wherein said filler alloy comprises 0.006-0.03 wt. % sodium.  
     
     
         8 . The process for controlled atmosphere brazing of  claim 4 , wherein said filler alloy comprises 0.001-0.03 wt. % potassium.  
     
     
         9 . The process for controlled atmosphere brazing of  claim 4 , wherein said filler alloy comprises 0.03-0.1 wt. % bismuth.  
     
     
         10 . The process for controlled atmosphere brazing of  claim 9 , wherein said filler alloy comprises 0.03-0.08 wt. % bismuth.  
     
     
         11 . The process for controlled atmosphere brazing of  claim 1 , further comprising, providing a core alloy upon which said filler alloy is clad.  
     
     
         12 . The process for controlled atmosphere brazing of  claim 11 , wherein said core alloy is selected from the group consisting of 3XXX, 5XXX and 6XXX series alloys.  
     
     
         13 . The process for controlled atmosphere brazing of  claim 1 , wherein said controlled atmosphere is a non-oxidizing gas.  
     
     
         14 . The process for controlled atmosphere brazing of  claim 13 , wherein said non-oxidizing gas is nitrogen or argon.  
     
     
         15 . The process for controlled atmosphere brazing of  claim 13 , wherein said non-oxidizing gas contains less than 100 ppm of oxygen.  
     
     
         16 . The process for controlled atmosphere brazing of  claim 1 , wherein said incidental impurities include no more than 0.1 wt % magnesium and not more than 1.5 wt % manganese.  
     
     
         17 . The process of  claim 1 , further including the steps of providing an aluminum article to be brazed and cleaning said article with a caustic NaOh containing cleaner prior to brazing said aluminum article with said filler alloy.  
     
     
         18 . An aluminum filler alloy comprising, 
 a) 4-20 wt. % silicon;    b) 0.0008-0.06 wt. % sodium, and    c) the balance aluminum and incidental impurities.    
     
     
         19 . The aluminum filler alloy of  claim 18 , wherein said alloy comprises 0.005-0.05 wt. % sodium.  
     
     
         20 . The aluminum filler alloy of  claim 19 , wherein said alloy comprises 0.006-0.03 wt. % sodium.  
     
     
         21 . The aluminum filler alloy of  claim 18 , wherein said alloy further comprises at least one element selected from the group comprising 0.0005-0.03 wt. % potassium and 0.03-0.133 wt. % bismuth.  
     
     
         22 . The aluminum filler alloy of  claim 21 , wherein said alloy comprises 0.005-0.05 wt. % sodium.  
     
     
         23 . The aluminum filler alloy of  claim 22 , wherein said alloy comprises 0.006-0.03 wt. % sodium.  
     
     
         24 . The aluminum filler alloy of  claim 21 , wherein said alloy comprises both 0.0005-0.03 wt. % potassium and 0.03-0.133 wt. % bismuth.  
     
     
         25 . The aluminum filler alloy of  claim 21 , wherein said alloy comprises 0.001-0.03 wt. % potassium.  
     
     
         26 . The aluminum filler alloy of  claim 21 , wherein said alloy comprises 0.03-0.1 wt. % bismuth.  
     
     
         27 . The aluminum filler alloy of  claim 26 , wherein said alloy comprises 0.03-0.08 wt. % bismuth.  
     
     
         28 . The aluminum filler alloy of  claim 18 , wherein said incidental impurities include not more than 0.1 wt % magnesium and not more than 1.5 wt % manganese.

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