Heat Resistant Aluminum Alloy for Heat Exchangers

Abstract

The invention relates to a heat-resistant aluminium alloy for heat exchangers, a method for producing an aluminium strip or sheet for heat exchangers, and a corresponding aluminium strip or sheet. The aim of the invention is to provide an aluminium alloy and an aluminium strip or sheet which has a good recycling capacity, a Solidus temperature of at least 620° C., and an improved heat-resistance after welding. To this end, the inventive aluminium alloy comprises the following parts of alloy constituents in wL %: 0.3%≦Si≦1%, Fe≦0.5%, 0.3%≦Cu≦0.7%, 1.1%≦Mn≦1.8%, 0.15%≦Mg≦0.6%, 0.01%≦Cr≦0.3%, Zn≦0.10%, Ti≦0.3%, unavoidable impurities separately representing a maximum of 0.1%, and together a maximum of 0.15%, the remainder being aluminium.

1 . A heat resistant aluminium alloy for heat exchangers,  
     wherein 
 that the aluminium alloy comprises the following proportions of alloy components in weight percent:  
 0.3%≦Si≦1%,  
 Fe≦0.5%,  
 0.3%≦Cu≦0.7%,  
 1.1%≦Mn≦1.8%,  
 0.15%≦Mg≦0.6%,  
 0.01%≦Cr≦0.3%,  
 Zn≦0.10%,  
 Ti≦0.3%,  
 unavoidable impurities separately representing a maximum of 0.1%, together a maximum of 0.15%, and the remainder being aluminium.  
 
   
   
       2 . The aluminium alloy for heat exchangers according to  claim 1 ,  
     wherein 
 the aluminium alloy comprises the following proportions of alloy components in weight percent:  
 0.15%≦Mg≦0.3%  
 Zn≦0.05%  
 0.01%≦Ti≦0.3%.  
 
   
   
       3 . The aluminium alloy according to  claim 1 ,  
     wherein 
 that the aluminium alloy comprises the following proportions of the alloy components Si, Fe, Mn in weight percent:  
 0.5%≦Si≦0.8%  
 Fe≦0.35%,  
 1.1%≦Mn≦1.5%.  
 
   
   
       4 . A method for producing an aluminium strip or aluminium sheet for heat exchangers from a heat resistant aluminium alloy according to  claim 1 ,  
     wherein 
 a rolling ingot is cast in a continuous casting process, the rolling ingot is preheated at 400 to 500° C. prior to hot rolling, the rolling ingot is rolled to a hot strip, with the hot strip temperature being 250 to 380° C. and the hot strip thickness being 3 to 10 mm at the end of the hot rolling and the hot strip is cold rolled to final thickness.  
 
   
   
       5 . The method for producing an aluminium strip or aluminium sheet for heat exchangers according to  claim 4 ,  
     wherein 
 the rolling ingot is homogenized prior to the preheating.  
 
   
   
       6 . The method for producing an aluminium strip or aluminium sheet for heat exchangers according to  claim 4 ,  
     wherein 
 the hot strip is intermediately annealed at a temperature of 300 to 450° C.  
 
   
   
       7 . The method for producing an aluminium strip or aluminium sheet for heat exchangers according to  claim 4 ,  
     wherein, 
 during the cold rolling, the aluminium strip is intermediately annealed at a temperature of 300 to 450° C. prior to reaching the final thickness.  
 
   
   
       8 . The method for producing an aluminium strip or aluminium sheet for heat exchangers according to  claim 4 ,  
     wherein 
 subsequent to the cold rolling, a phase annealing step to the final state takes place at a temperature of 250 to 400° C.  
 
   
   
       9 . The method for producing an aluminium strip or aluminium sheet for heat exchangers according to  claim 4 ,  
     wherein 
 prior to the preheating, the rolling ingot is provided on one or two sides with plates made of another alloy.  
 
   
   
       10 . The method for producing an aluminium strip or aluminium sheet for heat exchangers according to  claim 9 ,  
     wherein 
 the plates are comprised of a solder alloy and as solder alloy there is used an aluminium solder, in particular an aluminium alloy comprising 6 to 13 weight percent Si, preferably an AMSi7.5 alloy or AlSi10 alloy.  
 
   
   
       11 . The method for producing an aluminium strip or aluminium sheet for heat exchangers according to  claim 4 ,  
     wherein 
 the hot strip is cold rolled to a final thickness of 0.1 to 2.0 mm.  
 
   
   
       12 . Aluminium strip or aluminium sheet comprised of an aluminium alloy according to  claim 1  produced according to a method according to  claim 4 .  
   
   
       13 . The aluminium strip or aluminium sheet according to  claim 12 ,  
     wherein 
 the aluminium strip is a tube strip, a tube plate strip, a side part strip or a disk strip for producing a heat exchanger.  
 
   
   
       14 . The aluminium strip or aluminium sheet according to  claim 13 ,  
     wherein 
 the tube strip has a final thickness of 0.15 to 0.6 mm, preferably 0.15 to 0.4 mm, the tube plate strip a final thickness of 0.8 to 2.5 mm, preferably 0.8 to 1.5 mm or the side part strip a final thickness of 0.8 to 1.8 mm, preferably 0.8 to 1.2 mm or the disk strip a final thickness of 0.3 to 1.0 mm, preferably 0.3 to 0.5 mm.