Method for casting aluminum alloy strips

Abstract

Method for manufacturing aluminum alloy strips with thickness<0.3 mm, to be used in the manufacture of brazed heat exchangers, with composition (% by weight): Si<1.5; Fe<2.5; Cu<0.8; Mg<1.0; Mn=<1.8; Zn<2.0; In<0.2; Sn<0.2; Bi<0.2; Ti<0.2; Cr<0.25; Zr<0.25; Si+Fe+Mn+Mg>0.8, other elements<0.05 each and<0.15 in total, with a difference of corrosion potential between the surface and the mid-thickness, measured with respect to a saturated calomel electrode according to ASTM standard G69 equal to at least 10 mV., by method steps of continuous casting at a thickness of between 1 and 30 mm under conditions that promote the formation of segregations in the strip core, optionally hot rolling, cold rolling optionally with at least one intermediate or final annealing lasting for 1 to 20 h at a temperature of between 200 and 450° C.

1 . Aluminium alloy strips with thickness<0.3 mm, to be used in the manufacture of brazed heat exchangers, with composition (% by weight): 
 Si<1.5; Fe<2.5; Cu<0.8; Mg<1.0; Mn=<1.8; Zn<2.0; In<0.2; Sn<0.2; Bi<0.2; Ti<0.2; Cr<0.25; Zr<0.25; Si+Fe+Mn+Mg>0.8, other elements<0.05 each and<0.15 in total, with a difference of corrosion potential between the surface and the mid-thickness, measured with respect to a saturated calomel electrode according to ASTM standard G69 equal to at least 10 mV.    
   
   
       2 - 10 . (canceled)  
   
   
       11 . Method for manufacturing aluminum alloy strips with thickness<0.3 mm, to be used in the manufacture of brazed heat exchangers, with composition (% by weight): 
 Si<1.5; Fe<2.5; Cu<0.8; Ma<1.0; Mn=<1.8; Zn<2.0; In<0.2; Sn<0.2; Bi<0.2; Ti<0.2; Cr<0.25; Zr<0.25; Si+Fe+Mn+Ma>0.8, other elements<0.05 each and<0.15 in total, with a difference of corrosion potential between the surface and the mid-thickness, measured with respect to a saturated calomel electrode according to ASTM standard G69 equal to at least 10 mV., by method steps comprising continuous casting at a thickness of between 1 and 30 mm under conditions that promote the formation of segregations in the strip core, optionally hot rolling, cold rolling optionally with at least one intermediate or final annealing lasting for 1 to 20 h at a temperature of between 200 and 450° C.    
   
   
       12 . Method according to  claim 11 , wherein the continuous casting is made between two cooled and shrinked rolls.  
   
   
       13 . Method according to  claim 12 , wherein the rolls apply a force during casting which is more than 100+2000/e t/m of width of the cast strip, where e is the thickness of the cast strip expressed in mm.  
   
   
       14 . Method according to  claim 12 , the metal and the rolls form a contact arc therebetween which is longer than 60 mm.  
   
   
       15 . Method according to  claim 12 , wherein the shells have a temperature which is less than 100° C.