High strength aluminium fin material for brazing

Abstract

The invention refers to an aluminium alloy, a clad or unclad material for brazed products containing said alloy as a core, as well as a method of producing materials to be used in brazed products from said alloy. The material is suitable for controlled atmosphere brazing (CAB) using fluxes that manage higher Mg levels in the materials. The alloy is intended as a fin-stock material for brazed products, such as heat exchangers. The alloy comprises 0.5-1.0 wt-% silicon, 0.25-0.6 wt-% magnesium, 0.3-0.7 wt-% manganese, and 0.05-0.25 wt-% zirconium, and optionally up to 4% Zn, the balance consisting of aluminium and unavoidable impurities. The method for producing the material comprises the steps of subjecting said alloy to a casting process and subjecting the cast alloy to hot rolling and a cold rolling process, possibly followed by an annealing process.

1 . An aluminium alloy for brazed products with high strength, characterized in that the alloy comprises 0.5-1.0 wt-% silicon, 0.25-0.6 wt-% magnesium, 0.3-0.7 wt-% manganese, and 0.05-0.25 wt-% zirconium, and optionally up to 4% Zn, the balance consisting of aluminium and unavoidable impurities, the Fe in said impurities being controlled up to 0.3%.  
     
     
         2 . An aluminium alloy according to  claim 1 , characterized in that the manganese content is 0.4-0.7 wt-%.  
     
     
         3 . An aluminium alloy according to  claim 1 , characterized in that the manganese content is 0.5-0.7 wt-%.  
     
     
         4 . An aluminium alloy according to any of claims  1 - 3 , characterized in that the silicon content is 0.6-0.9 wt-%.  
     
     
         5 . A clad material for brazed products with high strength, characterized in that the core alloy comprises 0.5-1.0 wt-% silicon, 0.25-0.6 wt-% magnesium, 0.3-0.7 wt-% manganese, and 0.05-0.25 wt-% zirconium and optionally up to 4% Zn, the balance consisting of aluminium and unavoidable impurities, the Fe in said impurities being controlled up to 0.3%.  
     
     
         6 . A clad material according to  claim 5 , characterized in that the manganese content is 0.4-0.7 wt-%.  
     
     
         7 . A clad material according to  claim 5  or  6 , characterized in that the manganese content is 0.5-0.7 wt-%.  
     
     
         8 . A clad material according to any of claims  5 - 7 , characterized in that the silicon content is 0.6-0.9 wt-%.  
     
     
         9 . A method of producing a material from the alloy of any of claims  1 - 8 , characterized by the steps of 
 subjecting said alloy to a casting process,    subjecting the obtained material to a hot rolling process    subjecting the obtained material to a cold rolling process.    
     
     
         10 . The method as claimed in  claim 9 , characterized in that after said casting process the material is scalped and clad with at least one additional layer.  
     
     
         11 . The method as claimed in claims  9  or  10 , characterized in that after said cold rolling the material is subjected to an annealing process.  
     
     
         12 . Use of the material in any of claims  1 - 8  to produce a fin-stock for heat exchangers.  
     
     
         13 . Use of the material in any of claims  1 - 8  in a brazing process where an inert atmosphere is used.  
     
     
         14 . Use of the material in any of claims  1 - 8  in a brazing process using a controlled atmosphere and a suitable flux.