High strength aluminum alloy fin stock for heat exchanger

Abstract

The present invention provides an aluminum alloy fm stock alloy material with higher strength, and improved sag resistance for use in heat exchangers. This aluminum alloy fm stock alloy material was made by direct chill (DC) casting.

1 . An aluminum alloy comprising about 0.8-1.4 wt % Si, 0.4-0.8 wt % Fe, 0.05-0.4 wt % Cu, 1.2-1.7 wt % Mn and 1.20-2.3 wt % Zn with the remainder as Al. 
     
     
       2. The aluminum alloy of  claim 1 , comprising about 0.9-1.3 wt % Si, 0.45-0.75 wt % Fe, 0.10-0.3 wt % Cu, 1.3-1.7 wt % Mn and 1.30-2.2 wt % Zn, with the remainder as Al. 
     
     
         3 . The aluminum alloy of  claim 1 , comprising about 0.9-1.2 wt % Si, 0.5-0.75 wt % Fe, 0.15-0.3 wt % Cu, 1.4-1.6 wt % Mn and 1.4-2.1 wt % Zn, with the remainder as Al. 
     
     
         4 . The aluminum alloy of  claim 1 , further comprising up to 0.2 wt % of one or both of Cr or Zr. 
     
     
         5 . An aluminum alloy fin stock material produced from the aluminum alloy of  claim 1  by a process, comprising:
 direct chill casting the aluminum alloy into an ingot; 
 preheating the ingot to 450 to 560° C. for 2 to 16 hours; 
 hot rolling the preheated ingot; 
 cold rolling the ingot; 
 inter-annealing at a temperature of 300-450° C.; and, 
 after inter-annealing, performing a final cold rolling step to achieve % cold work (%CW) of 25-35%. 
 
     
     
         6 . The aluminum alloy fin stock material of  claim 5 , wherein the ingot is preheated at 480° C. for 2-12 hours. 
     
     
         7 . The aluminum alloy fin stock material of  claim 5 , wherein the inter-annealing temperature is 300-400° C. 
     
     
         8 . The aluminum alloy fin stock material of  claim 5 , having a minimum ultimate tensile strength of ˜130 MPa, measured after brazing. 
     
     
         9 . The aluminum alloy fin stock material of  claim 5 , having a corrosion potential of −700 mV or less, measured after brazing. 
     
     
         10 . A heat exchanger comprising the aluminum alloy of  claim 1  or the aluminum alloy fin stock material of  claim 5 . 
     
     
         11 . The heat exchanger of  claim 10 , wherein the heat exchanger is an automotive heat exchanger. 
     
     
         12 . The heat exchanger of  claim 10 , wherein the heat exchanger is a radiator, a condenser or an evaporator. 
     
     
         13 . Use of the aluminum alloy of  claim 1  or the aluminum alloy fin stock material of  claim 5  for fabrication of heat exchanger fins. 
     
     
         14 . A process for making an aluminum alloy fin stock material, comprising:
 direct chill casting the aluminum alloy of  claim 1  into an ingot;   preheating the ingot to 450 to 560° C. for 2 to 16 hours;   hot rolling the preheated ingot;   cold rolling the ingot;   inter-annealing at a temperature of 300-450° C.; and,   after inter-annealing, performing a final cold rolling step to achieve % cold work (%CW) of 25-35%.   
     
     
         15 . The process of  claim 14 , wherein the ingot is preheated at 480° C. for 2-12 hours. 
     
     
         16 . The process of  claim 14 , wherein the inter-annealing temperature is 300-400° C. 
     
     
         17 . The process of  claim 15 , wherein the inter-annealing temperature is 300-400° C.