Highly corrosion-resistant heat exchanger system using control of alloy composition and alloy potential

Abstract

Disclosed is a technology for improving corrosion resistance of aluminum tubes, aluminum fins, and aluminum headers of a heat exchanger. The heat exchanger includes one or more tubes made of aluminum alloy, one or more headers made of aluminum alloy, one or more brazing header clads, one or more fins (or heat sinks) made of aluminum alloy, and one or more brazing fin clads. The corrosion potential of the tube ranges from −950 mV to −650 mV, the corrosion potential of the header has a difference of 0 mV to 150 mV with respect to the corrosion potential of the tube, and the corrosion potential of the header clad has a difference of −20 mV to 100 mV with respect to the corrosion potential of the tube.

1 . A highly corrosion resistant heat exchanger system in which an alloy composition and an alloy potential are differently set for each component of the heat exchanger system, the heat exchanger system comprising:
 one or more tubes made of an aluminum alloy;   one or more headers made of an aluminum alloy;   one or more brazing header clads; and   one or more fins (or heat sinks); and   one or more brazing fin clads,   wherein a corrosion potential of the tube ranges from −950 mV to −650 mV,   a corrosion potential of the header has a difference of +0 mV to +150 mV with respect to the corrosion potential of the tube,   a corrosion potential of the header cladding has a difference of −20 mV to +100 mV with respect to the corrosion potential of the tube,   a Cu content in the aluminum alloy ranges from 0.001% to 0.50% by weight,   a Zn content in the aluminum alloy ranges from 0.001% to 5.00% by weight, and the tubes, the headers, and the fins are joined by brazing the header clads and the fin clads.   
     
     
         2 . The heat exchanger system of  claim 1 , wherein the corrosion potential of the fin (or heat sink) has a difference of −20 mV to −170 mV with respect to the corrosion potential of the tube. 
     
     
         3 . The heat exchanger system of  claim 1 , wherein the corrosion potential of the fin clad has a difference of −40 mV to +80 mV with respect to the corrosion potential of the tube. 
     
     
         4 . The heat exchanger system of  claim 1 , wherein in the aluminum alloy, a change in the content of at least one element selected from Cu, Zn, Mn, Si, Fe, and Mg is a major control factor of the corrosion potential. 
     
     
         5 . The heat exchanger system of  claim 1 , wherein the aluminum alloy contains at least one rare earth metal selected from rare earth metals ranging from La of atomic number 57 to Lu of atomic number 71 in a proportion of 0.005% to 1.00% by weight. 
     
     
         6 . The heat exchanger system of  claim 1 , wherein the aluminum alloy contains at least 0.005% to 0.25% by weight of at least one element selected from Zr and B. 
     
     
         7 . The heat exchanger system of  claim 1 , wherein at least one process selected from aging heat treatment, zinc coating, conversion coating, resin coating, and any combination thereof is additionally performed on at least one of the tube, the fin (or heat sink), the header, and any combination thereof. 
     
     
         8 . A highly corrosion resistance heat exchanger system in which an alloy composition and an alloy potential are differently set for each component of the heat exchanger system, the heat exchanger system comprising a tube made of an aluminum alloy satisfying conditions specified below (wherein M in a formula below is 1 to 5):
 a content of Cu ranges from 0.001% to 0.50% by weight;   a content of Zn ranges from 0.001% to 5.00 wt %;   a content of at least one selected from among Zr and B is 0.001% to 0.25% by weight;   a content of at least one rare earth metal selected from the group consisting of rare earth metals ranging from lanthanum atoms (La, atomic number 57) to lutetium (Lu, atomic number 71) ranges from 0.001% to 1.00% by weight; and   S % in the following equations ranges from 0.05% to 0.30% by weight,   Equations:   where Z % is the content of one or more elements selected from among Zr and B;   R % is the content of at least one element selected from elements ranging from La (atomic number 57) to Lu (atomic number 71); and   S %=((R %/M)+Z %)   
     
     
         9 . The heat exchanger system of  claim 8 , wherein:
 the content of Cu is 0.001% to 0.12% by weight;   the content of Zn is 0.001% to 3.00% by weight;   a content of Fe is 0.001% to 0.25% by weight;   the content of at least one metal selected from rare earth metals ranging from La (atomic number 57) to Lu (atomic number 71) is 0.05% to 0.50% by weight; and   the content of at least one element selected from Zr and B ranges from 0.01 to 0.07% by weight.   
     
     
         10 . The heat exchanger system of  claim 8 , wherein the aluminum alloy contains Fe in a proportion of 0.40% to 0.70% by weight. 
     
     
         11 . (canceled)