Aluminum Alloy Heat Exchanger

Abstract

A core material contains Mn: 0.3-2.0 mass % (hereinafter, abbreviated to %), Si: 1.5% or less, Fe: 0.1-1.0% and Cu: 0.05-1.0%, and comprises a remainder Al and unavoidable impurities, and the sacrificial anode material contains Fe: 0.05-1.0% and Zn: 0.5-5.0%, and comprises a remainder Al and unavoidable impurities. A potential at the joint section between the header pipe and the tube is lower by 30 mV or less than potentials at the header pipe surface and the tube surface, and the potential at the joint section is lower by 30-100 mV than a potential at a position in a depth of one quarter of the overall thickness from the header pipe surface and a potential at a position in a depth of one quarter of the overall thickness from the tube surface.

1 . An aluminum alloy heat exchanger, wherein
 a plurality of tubes comprising fluid passages therein are arranged in parallel to each other,   a corrugated fin is sandwiched between the adjacent tubes,   header pipes are arranged on both ends of the tubes, and   the tubes, the fins and the header pipes are integrated by brazing, wherein:   the header pipe is composed of an aluminum alloy cladding material comprising an aluminum alloy core material and a sacrificial anode material for cladding at least one side of the core material;   the core material contains Mn: 0.3-2.0 mass % (hereinafter, abbreviated to %), Si: 1.5% or less, Fe: 0.1-1.0% and Cu: 0.05-1.0%, and comprises a remainder Al and unavoidable impurities;   the sacrificial anode material contains Fe: 0.05-1.0% and Zn: 0.5-5.0%, and comprises a remainder Al and unavoidable impurities;   a potential at the joint section between the header pipe and the tube is less noble by 30 mV or less than potentials at the header pipe surface and the tube surface; and   the potential at the joint section is less noble by 30-100 mV than a potential at a position in a depth of one quarter of the overall thickness from the header pipe surface and a potential at a position in a depth of one quarter of the overall thickness from the tube surface.   
     
     
         2 . The aluminum alloy heat exchanger according to  claim 1 , wherein:
 a braze-functionalized sacrificial anode material is used instead of the sacrificial anode material; and   the braze-functionalized sacrificial anode material contains Si: 2.5-15.0%, Fe: 0.05-1.0% and Zn: 0.5-5.0%, and comprises a remainder Al and unavoidable impurities.   
     
     
         3 . The aluminum alloy heat exchanger according to  claim 1 , wherein the alloy component of the core material of the header pipe further contains one or more selected from Mg: 0.1-1.0%, Ti: 0.05-0.3%, Zr: 0.05-0.3%, Cr: 0.05-0.3%, and V: 0.05-0.3%. 
     
     
         4 . The aluminum alloy heat exchanger according to  claim 1 , wherein the alloy component of the sacrificial anode material or the braze-functionalized sacrificial anode material further contains one or more selected from Mn: 0.05-1.0%, Ti: 0.05-0.3%, Zr: 0.05-0.3%, Cr: 0.05-0.3%, V: 0.05-0.3%, Na: 0.001-0.05% and Sr: 0.001-0.05%. 
     
     
         5 . The aluminum alloy heat exchanger according to  claim 1 , wherein:
 the core material on the side opposite to a surface on which the header pipe core material is cladded with the sacrificial anode material of the header pipe or the braze-functionalized sacrificial anode material is cladded with a brazing material; and   the brazing material contains Si: 2.5-15.0%, Fe: 0.05-1.0%, further contains one or more selected from Mn: 0.05-1.0%, Ti: 0.05-0.3%, Zr: 0.05-0.3%, Cr: 0.05-0.3%, V: 0.05-0.3%, Na: 0.001-0.05% and Sr: 0.001-0.05%, and comprises a remainder Al and unavoidable impurities.   
     
     
         6 . The aluminum alloy heat exchanger according to  claim 1 , wherein the header pipe is an electric resistance welded tube processed by electric resistance welding. 
     
     
         7 . The aluminum alloy heat exchanger according to  claim 1 , wherein the header pipe is an extruded tube processed by extrusion of aluminum. 
     
     
         8 . The aluminum alloy heat exchanger according to  claim 1 , wherein:
 the tube is composed of the aluminum alloy cladding material comprising the aluminum alloy core material and the braze-functionalized sacrificial anode material for cladding at least one side of the core material;   the core material contains Mn: 0.5-2.0%, Si: 1.5% or less, Fe: 0.1-1.0%, Cu: 0.1-1.0%, further contains one or more selected from Mg: 0.1-1.0%, Ti: 0.05-0.3%, Zr: 0.05-0.3%, Cr: 0.05-0.3%, and V: 0.05-0.3%, and comprises a remainder Al and unavoidable impurities; and   the braze-functionalized sacrificial anode material contains Si: 2.5-15.0%, Fe: 0.05-1.0%, Zn: 0.5-5.0%, further contains one or more selected from Mn: 0.05-1.0%, Ti: 0.05-0.3%, Zr: 0.05-0.3%, Cr: 0.05-0.3%, V: 0.05-0.3%, Na: 0.001-0.05% and Sr: 0.001-0.05%, and comprises a remainder Al and unavoidable impurities.   
     
     
         9 . The aluminum alloy heat exchanger according to  claim 1 , wherein:
 the tube is composed of the aluminum alloy core material and a Zn thermal spraying material formed on a surface of the core material; and   the core material contains Si: 1.5% or less, Fe: 0.1-1.0%, Cu: 0.1-1.0%, further contains one or more selected from Mg: 0.1-1.0%, Ti: 0.05-0.3%, Zr: 0.05-0.3%, Cr: 0.05-0.3%, and V: 0.05-0.3%, and comprises a remainder Al and unavoidable impurities.