Highly corrosion-resistant aluminum alloy for heat exchanger tube and method for manufacturing heat exchanger tube using the same

Abstract

Disclosed are a highly corrosion-resistant aluminum alloy for a heat exchanger tube and a method for manufacturing a heat exchanger tube using the same. The highly corrosion-resistant aluminum alloy includes 0.05 to 0.5 wt % of iron, 0.05 to 0.2 wt % of silicon, 0.6 to 1.2 wt % of manganese, 0.15 to 0.45 wt % of copper, 0.05 to 0.3 wt % of at least one of zirconium and boron, and the remainder of aluminum and impurities. The aluminum alloy aluminum alloy for a heat exchanger tube improves corrosion resistance without affecting the physical properties other than corrosion resistance, through improvement in composition of the alloy, and ensures sufficient corrosion resistance without thermal arc spraying of zinc, resulting in a simple process, which leads to improvement in manufacturing efficiency and productivity of products.

1 . A highly corrosion-resistant aluminum alloy for a heat exchanger tube, comprising:
 0.05 to 0.5 wt % of iron, 0.05 to 0.2 wt % of silicon, 0.6 to 1.2 wt % of manganese, 0.15 to 0.45 wt % of copper, 0.05 to 0.3 wt % of at least one of zirconium and boron, and the remainder of aluminum and impurities.   
     
     
         2 . The highly corrosion-resistant aluminum alloy for a heat exchanger tube according to  claim 1 ,
 wherein the content of iron is 0.05 to 0.3 wt %.   
     
     
         3 . The highly corrosion-resistant aluminum alloy for a heat exchanger tube according to  claim 2 ,
 wherein the content of zirconium or boron is 0.05 to 0.2 wt %.   
     
     
         4 . A highly corrosion-resistant aluminum alloy for a heat exchanger tube, comprising:
 0.05 to 0.5 wt % of iron, 0.05 to 0.2 wt % of silicon, 0.3 to 0.7 wt % of manganese, 0.3 to 0.7 wt % of copper, 0.05 to 0.3 wt % of at least one of zirconium and boron, and the remainder of aluminum and impurities.   
     
     
         5 . The highly corrosion-resistant aluminum alloy for a heat exchanger tube according to  claim 4 ,
 wherein the content of iron is 0.05 to 0.3 wt %.   
     
     
         6 . The highly corrosion-resistant aluminum alloy for a heat exchanger tube according to  claim 5 ,
 wherein the content of zirconium or boron is 0.05 to 0.2 wt %.   
     
     
         7 . A method for manufacturing a heat exchanger tube, comprising:
 thermally treating a billet or a wire rod at a temperature range between 450 and 650° C. for 10 to 25 hours, the billet or the wire rod being made from an aluminum alloy comprising 0.05 to 0.5 wt % of iron, 0.05 to 0.2 wt % of silicon, 0.6 to 1.2 wt % of manganese, 0.15 to 0.45 wt % of copper, 0.05 to 0.3 wt % of at least one of zirconium and boron, and the remainder of aluminum and impurities; and   performing a direct extrusion or a conform extrusion on the billet or the wire rod to manufacture a heat exchanger tube.   
     
     
         8 . The method for manufacturing a heat exchanger tube according to  claim 7 ,
 wherein the content of iron is 0.05 to 0.3 wt %.   
     
     
         9 . The method for manufacturing a heat exchanger tube according to  claim 8 ,
 wherein the content of zirconium or boron is 0.05 to 0.2 wt %.   
     
     
         10 . The method for manufacturing a heat exchanger tube according to  claim 9 ,
 wherein an alloy molten metal is poured at a temperature range between 750 and 900° C. to produce the billet by continuous casting or to produce the wire rod by continuous casting and rolling (properzi).   
     
     
         11 . The method for manufacturing a heat exchanger tube according to  claim 10 , further comprising:
 performing thermal arc spraying (TAS) on the surface of the heat exchanger tube.   
     
     
         12 . The method for manufacturing a heat exchanger tube according to  claim 11 ,
 wherein the heat exchanger tube has a controlled crystal grain size of 50 μm or less after the direct extrusion or the conform extrusion and a controlled crystal grain size of 70 μm or less after the brazing-thermal treatment.   
     
     
         13 . A method for manufacturing a heat exchanger tube, comprising:
 thermally treating a billet or a wire rod at a temperature range between 450 and 650° C. for 10 to 25 hours, the billet or the wire rod being made from an aluminum alloy comprising 0.05 to 0.5 wt % of iron, 0.05 to 0.2 wt % of silicon, 0.3 to 0.7 wt % of manganese, 0.3 to 0.7 wt % of copper, 0.05 to 0.3 wt % of at least one of zirconium and boron, and the remainder of aluminum and inevitable impurities; and   performing a direct extrusion or a conform extrusion on the billet or the wire rod to manufacture a heat exchanger tube.   
     
     
         14 . The method for manufacturing a heat exchanger tube according to  claim 13 ,
 wherein the content of iron is 0.05 to 0.3 wt %.   
     
     
         15 . The method for manufacturing a heat exchanger tube according to  claim 14 ,
 wherein the content of zirconium or boron is 0.05 to 0.2 wt %.   
     
     
         16 . The method for manufacturing a heat exchanger tube according to  claim 15 ,
 wherein an alloy molten metal is poured at a temperature range between 750 and 900° C. to produce the billet by continuous casting or to produce the wire rod by continuous casting and rolling (properzi).   
     
     
         17 . The method for manufacturing a heat exchanger tube according to  claim 16 , further comprising:
 performing thermal arc spraying on the surface of the heat exchanger tube.   
     
     
         18 . The method for manufacturing a heat exchanger tube according to  claim 17 ,
 wherein the heat exchanger tube has a controlled crystal grain size of 50 μm or less after the direct extrusion or the conform extrusion and a controlled crystal grain size of 70 μm or less after the brazing-thermal treatment.