Ultra-longlife, high formability brazing sheet

Abstract

The present invention relates to the process used to fabricate a multiple layer aluminum brazing sheet having a core, a braze cladding, and an interliner therebetween that, when fabricated in the fully annealed condition (O-temper), forms a continuous and dense dispersoid band in the core in addition to having an additional sacrificial layer for exceptional post brazed corrosion resistance.

1 . A process of producing a corrosion resistant aluminum brazing sheet product consisting of: 
 (a) producing a composite of an aluminum alloy interliner sandwiched between a 4xxx alloy braze cladding and a 3xxx alloy core;    (b) hot rolling the composite below 525° C. to metallurgically bond the components of the composite together; and    (c) cold rolling the composite to final gauge without exposure to a thermal treatment.    
   
   
       2 . The process of  claim 1  wherein step (a) comprises casting the braze cladding, the interliner and the core alloys as separate ingots and stacking the ingots into the composite.  
   
   
       3 . The process of  claim 1  wherein step (a) comprises simultaneously casting the core alloy and the braze cladding alloy on opposing sides of a solid interliner to produce the composite.  
   
   
       4 . The process of  claim 1  wherein step (a) comprises continuous casting the core alloy against the interliner, the interliner being pre-bonded to the braze cladding to produce the composite.  
   
   
       5 . The process of  claim 1  wherein the product rolled to final gauge is partially annealed to an —H temper.  
   
   
       6 . The process of  claim 1  wherein the product rolled to final gauge is fully annealed to an —O temper.  
   
   
       7 . The process of  claim 1  wherein the product obtained is subjected to a brazing event whereby a dense band of Mn containing dispersoids form in the core at the core/interliner interface.