Clad sheets for heat exchangers

Abstract

This application discloses a material comprising an aluminum metal alloy cladding fusion-cast to a metal alloy core. Also disclosed is a material comprising a metal core comprising a high content of scrap metal and having two sides, a first aluminum metal cladding fusion cast to the first side of the core layer, and a second aluminum metal cladding fusion cast to the second side of the core layer. The materials can be in a form of a sheet. Sheets are roll bonded together to create permanent metallurgical bonds except at regions where a weld-stop ink is applied. The sheets are used to make corrosion resistant heat exchangers.

1 . A composite metal sheet comprising a first clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt % and a core layer, wherein the first clad layer is adjacent to a first side of the core layer. 
     
     
         2 . The composite metal sheet of  claim 1 , further comprising a second clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt % and the second clad layer is adjacent to a second side of the core layer. 
     
     
         3 . The composite metal sheet of  claim 1 , wherein the core layer comprises a AA5XXX aluminum alloy. 
     
     
         4 . The composite metal sheet of  claim 2 , wherein the core layer comprises aluminum comprising scrap metal input. 
     
     
         5 . A method of making the composite metal sheet of  claim 1  comprising roll bonding the first clad layer and the core layer. 
     
     
         6 . A method of making the composite metal sheet of  claim 2  comprising fusion casting the first clad layer, the core layer and the second clad layer to form an ingot and then rolling the ingot to make the composite metal sheet. 
     
     
         7 . Use of the composite metal sheet of  claim 1  in the formation of a heat exchanger. 
     
     
         8 . A heat exchanger comprising the composite metal sheet of  claim 1 . 
     
     
         9 . A method of making a heat exchanger comprising:
 a. obtaining a first composite metal sheet comprising a first clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt % and a core layer, wherein the first clad layer is adjacent to a first side of the core layer;   b. obtaining a second composite metal sheet comprising a first clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt % and a core layer, wherein the first clad layer is adjacent to a first side of the core layer;   c. applying weld stop ink to selected regions of the first clad layer of a first composite metal sheet;   d. placing the first clad layer of the first composite metal sheet adjacent to the first clad layer of the second composite metal sheet wherein the selected regions are between the first composite metal sheet and the second composite metal sheet;   e. roll-bonding the two composite metal sheets; and,   f. inflating the selected regions to form channels.   
     
     
         10 . A method of making a heat exchanger comprising:
 a. obtaining a first composite metal sheet comprising a first clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt %, a core layer comprising aluminum scrap metal, and a second clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt %, wherein the first clad layer is adjacent to a first side of the core layer and the second clad layer is adjacent to a second side of the core layer;   b. obtaining a second composite metal sheet comprising a first clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt %, a core layer comprising aluminum scrap metal, and a second clad layer comprising an AA1XXX or an AA3XXX aluminum alloy wherein the Mg content is <0.2 wt %, wherein the first clad layer is adjacent to a first side of the core layer and the second clad layer is adjacent to a second side of the core layer;   c. applying weld stop ink to selected regions of the first or second composite metal sheet;   d. contacting the first composite metal sheet with the second composite metal sheet such that the selected regions are between the first composite metal sheet and the second composite metal sheet;   e. roll-bonding the two composite metal sheets; and,   f. inflating the selected regions to form channels.   
     
     
         11 . A heat exchanger made by the method of  claim 9 . 
     
     
         12 . A heat exchanger made by the method of  claim 10 . 
     
     
         13 . Use of the composite metal sheet of  claim 2  in the formation of a heat exchanger. 
     
     
         14 . A heat exchanger comprising the composite metal sheet of  claim 2 .