JPH11241133A - High corrosion resistant aluminum alloy clad material and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a high corrosion resistant aluminum alloy clad material capable of obtaining sufficient corrosion resistance under both acidic and alkaline corrosive environments. SOLUTION: An aluminum alloy, having a composition consisting of, by weight, 0.05-1.2% Si, 0.05-0.8% Fe, 0.003-<0.01% Cu, 0.5-2.0% Mn, and the balance Al with inevitable impurities, is used as a core material. One side of this core material is clad with an aluminum alloy having a composition consisting of, by weight, 2.0-6.0% Zn and the balance Al with inevitable impurities, as a sacrificial anode material. The resultant clad material is suited for heat exchanger use and used for tube material, header plate material, etc., for a heat exchanger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly corrosion-resistant aluminum alloy composite material and a method for producing the same, and more particularly to a highly corrosion-resistant aluminum alloy composite material suitable for a heat exchanger and applicable to both acidic and alkaline refrigerants, and a method for producing the same. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, in a heat exchanger, for example, a heat exchanger (radiator) for an automobile, fins are arranged between tube tubes through which a refrigerant passes, and header plates are attached to both ends of the tube tubes to assemble a core. After brazing this assembly, a resin tank is attached to the header plate via packing, and the refrigerant is cooled by passing the refrigerant through the tube tube of such a radiator.

[0003] The fins of such a heat exchanger include JIS.
A thin plate in which about 1.5 wt% of Zn is added to a −3003 alloy is used. JIS-3003 for the tube
Using an alloy as the core material, brazing material on one side and JIS- on the other side
Aluminum alloy composite material (brazing sheet) clad with 7072 alloy as sacrificial anode material to prevent pitting corrosion
Is used in which the sacrificial anode material is placed inside (coolant side) and subjected to electric resistance welding in a cylindrical shape. The aluminum alloy composite material of the same material as the tube tube is used for the header plate. In recent years, the weight of the heat exchanger has been required to be reduced. However, when the thickness of the member is reduced in order to reduce the weight of the heat exchanger, it is necessary to improve the corrosion resistance of the member. For this purpose, there has been proposed an aluminum alloy composite material in which an additive element is further added to a core material and a sacrificial anode material (for example, JP-A-7-41894).

[0004]

It is known that a tube tube using the above-mentioned conventional aluminum alloy composite material shows sufficient corrosion resistance in an acidic corrosion environment. However, recently, an alkaline refrigerant is sometimes used, and a material that can withstand not only an acidic environment but also an alkaline corrosive environment has been required. However, when an aluminum alloy is used for the tube, aluminum hydroxide is generated in an alkaline environment, and a thick film of aluminum hydroxide is formed on the inner surface of the tube. In the conventional tube tube, a film of aluminum hydroxide is formed on the surface of the sacrificial anode material in an alkaline environment, and in such a state, the anticorrosion effect of the sacrificial anode material on the core material is lost. I will.

[0005] In view of the above, the present inventors have conducted intensive studies and studied the components of the core material and the sacrificial anode material to find out that the aluminum alloy composite material has excellent corrosion resistance under both acidic and alkaline corrosion environments. The present inventors have found that the present invention can be realized, and have conducted further research to complete the present invention. An object of the present invention is to provide a highly corrosion-resistant aluminum alloy composite material that has sufficient corrosion resistance under both acidic and alkaline corrosion environments.

[0006]

Means for Solving the Problems The present invention (the invention according to claim 1) is based on the following facts: Si: 0.05 to 1.2 wt%, Fe:
0.05-0.8 wt%, Cu: 0.003-0.01
Less than wt%, Mn: 0.5 to 2.0 wt%, aluminum alloy consisting of the remaining Al and unavoidable impurities is used as a core material, and Zn: 2.0 to 6.0 wt% is contained on one surface of the core material. A high corrosion-resistant aluminum alloy composite material characterized by being clad as a sacrificial anode material with an aluminum alloy comprising the remaining Al and unavoidable impurities. In addition, the present invention (the invention described in claim 2) is characterized in that Si: 0.05 to 1.2.
wt%, Fe: 0.05 to 0.8 wt%, Cu: 0.0
03 to less than 0.01 wt%, Mn: 0.5 to 2.0 wt%
%, And an aluminum alloy containing the balance of Al and unavoidable impurities is used as a core material, and Zn: 2.0 to
6.0 wt%, Mn: 0.5-2.0 wt%,
A highly corrosion-resistant aluminum alloy composite material characterized by cladding an aluminum alloy consisting of the remainder Al and inevitable impurities as a sacrificial anode material.

Further, the present invention (the invention according to claim 3)
Is: Si: 0.05 to 1.2 wt%, Fe: 0.05 to
0.8 wt%, Cu: 0.003 to less than 0.01 wt%, Mn: 0.5 to 2.0 wt%, and Cr:
0.01-0.3 wt%, Zr: 0.01-0.3 wt%
%, Ti: 0.01 to 0.3 wt%, Mg 0.2 wt%
An aluminum alloy containing one or more of the following, the balance being Al and unavoidable impurities is used as a core material, and one side of the core material contains Zn: 2.0 to 6.0 wt%, A highly corrosion-resistant aluminum alloy composite material characterized by cladding an aluminum alloy comprising unavoidable impurities as a sacrificial anode material. The present invention (claim 4)
The invention described in (1) is characterized in that: Si: 0.05 to 1.2 wt%,
e: 0.05 to 0.8 wt%, Cu: 0.003 to 0.
Less than 01 wt%, Mn: 0.5 to 2.0 wt%, Cr: 0.01 to 0.3 wt%, Zr: 0.0
1 to 0.3 wt%, Ti: 0.01 to 0.3 wt%, M
g: An aluminum alloy containing one or more of 0.2 wt% or less and the balance being Al and unavoidable impurities is used as a core material, and Zn: 2.0 to 6.0 w on one surface of the core material.
t%, Mn: 0.5 to 2.0 wt%, with the balance being Al
A highly corrosion-resistant aluminum alloy composite for heat exchangers, characterized in that an aluminum alloy composed of aluminum alloy and unavoidable impurities is clad as a sacrificial anode material.

Further, the present invention (the invention according to claim 5)
Is characterized in that the core aluminum alloy of the highly corrosion-resistant aluminum alloy composite material according to any one of the above (claims 1, 2, 3, 4) is an aluminum alloy further containing B: 0.05 wt% or less. It is a high corrosion resistant aluminum alloy composite material. That is, claim 1 in claim 5
The constituent elements of the invention cited are: Si: 0.05 to 1.2.
wt%, Fe: 0.05 to 0.8 wt%, Cu: 0.0
03 to less than 0.01 wt%, Mn: 0.5 to 2.0 wt%
%, Further containing B: 0.05 wt% or less, an aluminum alloy comprising the balance of Al and unavoidable impurities as a core material, and containing Zn: 2.0 to 6.0 wt% on one surface of the core material; A highly corrosion-resistant aluminum alloy composite material characterized by cladding an aluminum alloy consisting of the remainder Al and inevitable impurities as a sacrificial anode material. Claim 5
The constitutional requirements of the invention citing claim 2 in Si are as follows:
0.05-1.2wt%, Fe: 0.05-0.8wt
%, Cu: 0.003 to less than 0.01 wt%, Mn:
0.5 to 2.0 wt%, B: 0.05 wt%
% Or less, and an aluminum alloy comprising the balance of Al and inevitable impurities is used as a core material, and Zn: 2.0
A highly corrosion-resistant aluminum alloy composite material containing -6.0 wt%, Mn: 0.5-2.0 wt%, and clad as a sacrificial anode material with an aluminum alloy containing the balance of Al and inevitable impurities.

Further, the constituent elements of the invention citing claim 3 in claim 5 are as follows: Si: 0.05 to 1.2 wt%;
Fe: 0.05 to 0.8 wt%, Cu: 0.003 to
Less than 0.01 wt%, Mn: 0.5 to 2.0 wt%, Cr: 0.01 to 0.3 wt%, Zr: 0.
01-0.3 wt%, Ti: 0.01-0.3 wt%,
One or more of Mg of 0.2 wt% or less, B: 0.05 wt% or less, and a core material of an aluminum alloy containing the balance of Al and unavoidable impurities, and Zn: A highly corrosion-resistant aluminum alloy composite material containing 2.0 to 6.0 wt% and clad as an sacrificial anode material with an aluminum alloy containing the balance of Al and inevitable impurities. In the fifth aspect, the constituent elements of the invention citing the fourth aspect are as follows: Si: 0.05
１．２1.2 wt%, Fe: 0.05-0.8 wt%, Cu: 0.003-0.01 wt%, Mn: 0.5
~ 2.0wt%, Cr: 0.01 ~ 0.3wt
%, Zr: 0.01-0.3 wt%, Ti: 0.01-
0.3 wt%, Mg: One or more of 0.2 wt% or less, B: 0.05 wt% or less, and the core material is an aluminum alloy containing Al and unavoidable impurities. Zn: 2.0 to 6.0 w on one surface of the core material
t%, Mn: 0.5 to 2.0 wt%, with the balance being Al
And an aluminum alloy comprising unavoidable impurities and a clad as a sacrificial anode material.

Further, the present invention (the invention according to claim 6)
Is an Al-Si based alloy or Al-Si
-A highly corrosion-resistant aluminum alloy composite material as described above, wherein a Zn-based alloy is clad as a brazing material. That is, an aluminum alloy having the above-described composition is used as a core material, and one side of the core material is clad with an aluminum alloy having the above-described composition as a sacrificial anode material.
A highly corrosion-resistant aluminum alloy composite material characterized by being clad with an l-Si alloy or an Al-Si-Zn alloy as a brazing material. Further, the present invention (the invention according to claim 7) is characterized in that a highly corrosion-resistant aluminum alloy composite material is used for a heat exchanger. For example, it is used for a tube material of a heat exchanger, a head blade material, a fin material, and the like. In addition, the present invention (the invention described in claim 8) is based on the above (claims 1, 2, 3, 4, 5,
A heat exchanger characterized in that any or all of a tube tube, a fin, and a header plate are formed using the highly corrosion-resistant aluminum alloy composite material according to any one of 6).

Further, the present invention (the invention according to claim 9)
Is characterized in that a sacrificial anode material is superposed on one side of a core material and hot-rolled and cold-rolled, and if necessary, intermediate annealing is performed after cold-rolling and then cold-rolled (claims 1 and 2). ,
A method for producing a highly corrosion-resistant aluminum alloy composite according to any one of 3, 4, 5). That is, a sacrificial anode material is superposed on one surface of a core material of a high corrosion-resistant aluminum alloy composite material, and hot rolling and cold rolling are performed to produce a composite material. Alternatively, after hot rolling and cold rolling, intermediate annealing is performed and then cold rolling is performed to produce a composite material. In addition, the present invention (the invention according to claim 10) provides hot rolling and cold rolling by laminating a sacrificial anode material on one surface of the core material and a brazing material on the other surface, and optionally after cold rolling. The method for producing a highly corrosion-resistant aluminum alloy composite material according to the above (claim 6), characterized by intermediately annealing and then cold rolling. That is, a composite material is manufactured by laminating a sacrificial anode material on one surface of a core material of a high corrosion-resistant aluminum alloy composite material and a brazing material on the other surface and performing hot rolling and cold rolling. Or hot rolling,
After cold rolling, intermediate annealing is performed and then cold rolling is performed to produce a composite material.

[0012]

The highly corrosion-resistant aluminum alloy composite comprising the core material and the sacrificial anode material of the present invention has excellent corrosion resistance under both acidic and alkaline corrosion environments. The significance of the added elements and the reasons for limiting the composition range will be described. In the aluminum alloy composite of the present invention, the most important components for imparting sufficient corrosion resistance under both acidic and alkaline corrosion environments are the Cu content in the core material and the Zn content in the sacrificial anode material.
Quantity.

In an aluminum alloy composite material, a thick film of aluminum hydroxide is formed in an alkaline corrosion environment. Therefore, even if a sacrificial anticorrosion material is provided, the sacrificial anticorrosion effect does not work.
For this reason, it is necessary to improve the pitting corrosion resistance of the core material itself under alkaline environment corrosion. Corrosion in an alkaline corrosive environment proceeds from a defective portion of the aluminum hydroxide film on the surface. When the film has few defects, corrosion concentrates on the defective portion, so that deep pitting occurs locally. However, since the aluminum hydroxide film itself has the function of protecting the underlying aluminum, if there are many defects in the film, the protective effect of the film is lost and the underlying aluminum is severely dissolved, increasing the amount of corrosion. I do. Therefore, in order to improve the corrosion resistance in an alkaline corrosion environment, it is necessary to control the number of defects in the coating.

As a result of examining the mechanism of the occurrence of film defects in an alkaline corrosive environment, it was found that Cu
Is found to be formed on the surface of the core material after it is dissolved in the alkaline corrosion environment, and the number of film defects in the alkali corrosion environment is controlled by controlling the Cu content in the core material. I found what I can do. By reducing the content of Cu in the core material to less than 0.01 wt%, defects in the aluminum hydroxide film are reduced, and the film can exhibit a protective effect on the underlying aluminum. Further, the content of Cu in the core material is 0.003.
By setting the content to not less than wt%, it is possible to create an appropriate number of defective portions in the coating and to prevent the occurrence of deep pitting corrosion due to the concentration of corrosion at the defective portions of the coating. From the above, C of core material
The content of u is specified to be 0.003 to less than 0.01 wt%. Desirable Cu content is 0.003-0.008w
t%. Further, when the Cu content of the core material is 0.003 to
When the content is less than 0.01 wt%, the potential becomes lower than that of the JIS-3003 alloy conventionally used as the core material. Therefore, in order to ensure corrosion resistance in an acidic environment, the sacrificial anode material must be It has been found that it is necessary to combine the Zn content with a sacrificial anode material having a Zn content of 2 wt% or more. Note that Cu
The effect of Si, Fe, Mn, Cr, Zr, Ti, M
Even if g, B, etc. are included within the scope of the present invention, the effect can be sufficiently obtained.

[0015] Si forms a solid solution in the matrix after brazing and contributes to improvement in strength. Si content of 0.05 to
The reason why the content is defined as 1.2 wt% is that if the content is less than 0.05 wt%, the effect cannot be sufficiently obtained, and if the content exceeds 1.2 wt%, simple Si is precipitated and the self-corrosion resistance of the core material is reduced. is there. Desirable content of Si is 0.05 to 0.8
wt%. Fe has a function of distributing a coarse intermetallic compound in the alloy, making crystal grains of the core material fine, and preventing cracking during forming. Fe content of 0.05 to
The reason for defining the content to be 0.8 wt% is that if the content is less than 0.05 wt%, the effect cannot be sufficiently obtained, and if the content exceeds 0.8 wt%, the self-corrosion resistance of the core material is reduced. The desirable content of Fe is 0.05 to 0.3 wt%. Mn
Disperses fine intermetallic compounds in the alloy and improves the strength without lowering the corrosion resistance. The reason for defining the content of Mn to be 0.5 to 2.0 wt% is that 0.5 wt%
If the amount is less than 2.0%, the effect cannot be sufficiently obtained, and if the amount exceeds 2.0% by weight, the workability deteriorates and the yield decreases. The desirable content of Mn is 0.5 to 1.5 wt%.

The selected elements Cr, Zr,
Ti and Mg contribute to improvement in strength. Of these, Cr, Z
If the content of each of r and Ti is less than 0.01 wt%, the effect cannot be sufficiently obtained. If the content exceeds 0.3 wt%, casting cracks may occur. The desired content of each is 0.1.
08 to 0.2 wt%. Mg contributes to the strength improvement by precipitating the Mg ₂ Si compound together with the core material Si. The reason for limiting the Mg content to 0.2 wt% or less is that, when the content exceeds 0.2 wt%, when brazing, Mg diffuses into the brazing material clad on one side of the core material and reacts with the flux to form a brazing material. Is to be reduced. Further, B contributes to refinement of the ingot structure, and its effect can be obtained at 0.05 wt% or less. The unavoidable impurity elements may be contained as long as each is 0.05 wt% or less.

Next, the alloying elements of the sacrificial anode material will be described. Zn has an effect of protecting the core material by a sacrificial anticorrosion effect in an acidic corrosive environment. The reason for defining the Zn content to be 2.0 to 6.0 wt% is that 2.0 wt%.
If the amount is less than 6.0%, the effect is not sufficient. If the amount exceeds 6.0% by weight, the rollability of the alloy is reduced, and the yield is reduced. The desirable content of Zn is 2.0 to 4.0 wt%. Mn distributes fine intermetallic compounds in the alloy,
Improves strength without changing film properties under alkaline corrosion environment. Mn content of 0.5 to 2.0 wt
The reason for defining the percentage is that if the content is less than 0.5 wt%, the effect cannot be sufficiently obtained, and if it exceeds 2.0 wt%, the workability deteriorates and the yield decreases. The desirable content of Mn is 0.5 to 1.5 wt%. Further, the amount of Mn contained in the sacrificial anode material is preferably smaller than the amount of Mn contained in the core material. Mn has the effect of making the natural potential of the aluminum alloy noble, and when the amount of Mn contained in the sacrificial anode material is larger than the amount of Mn contained in the core material, the potential difference between the sacrificial anode material and the core material decreases. In such a case, the sacrificial anticorrosive action of the sacrificial anode material in an acidic corrosive environment is reduced, and the corrosion resistance is reduced.

The above is the description of the alloy elements of the sacrificial anode material used in the present invention. As an unavoidable impurity of the sacrificial anode material, Si can be contained up to 0.5 wt%.
0.1 wt% or less is desirable. Fe can be contained up to 0.8 wt%, but is preferably 0.1 wt% or less. Elements other than the above may be contained as impurity elements as long as each is 0.05 wt% or less. In the present invention, the Al-Si alloy or Al-
The cladding is performed using a Si—Zn alloy as a brazing material.
i-based JIS-4343 alloy, JIS-4045 alloy,
JIS-4004 alloy or the like can be used.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the aluminum alloy composite of the present invention will be described. The aluminum alloy composite material of the present invention is a composite material in which an aluminum alloy having the above composition is used as a core material, and one surface of which is clad with an aluminum alloy sacrificial anode material having the above composition. Further, there is a composite material in which an aluminum alloy sacrificial anode material having the above composition is clad on one surface of a core material and an aluminum alloy brazing material having the above composition is clad on another surface.
As a method of manufacturing the composite material of the present invention, an aluminum alloy as a core material is cast, the surface is ground, and finished by hot rolling. Also, the sacrificial anode material is cast and then beveled and finished by hot rolling. In addition, brazing material is cast, and is finished by hot rolling after facing. The core material and the sacrificial anode material are stacked, and hot-rolled and cold-rolled to produce a two-layer clad material. A high corrosion-resistant aluminum alloy in which the core material and the sacrificial anode material are stacked, hot-rolled, cold-rolled, then annealed, and then cold-rolled, and the sacrificial anode material is clad on one surface of the core material. Manufacture composites. Further, the brazing material, the core material, and the sacrificial anode material are stacked in this order, and hot-rolled and cold-rolled to produce a three-layer clad high corrosion-resistant aluminum alloy composite material. In addition, the brazing material, the core material, the sacrificial anode material, three sheets are stacked, hot-rolled, cold-rolled, and then subjected to intermediate annealing,
Further, the core material is cold-rolled to produce a three-layer high corrosion-resistant aluminum alloy composite material in which a sacrificial anode material is clad on one surface of the core material.

The highly corrosion-resistant aluminum alloy composite material of the present invention is used for heat exchangers such as radiators for automobiles, heater cores, oil coolers, and the like. Used for etc. Particularly, it is suitable for a tube tube of a heat exchanger for an automobile or the like. When the aluminum alloy composite material of the present invention is used as a tube tube, a method of forming the tube by electric resistance welding or a method of forming a tube by brazing after bending is preferably used.

FIG. 1 shows an example of a heat exchanger (radiator) for an automobile, which is an application of the composite material of the present invention.
This will be described in (a) and (b). FIG. 1A is a front view of a heat exchanger (radiator) for an automobile, and FIG.
It is a sectional enlarged view. The fins 2 are arranged between the tube tubes 1 through which the refrigerant passes, and the header plates 3 are attached to both ends of the tube tubes 1 to assemble the core 4. After the assembly is brazed, the header plate 3 is inserted through the packing 5. It is manufactured with resin tanks 6 and 7 attached. The refrigerant is passed through the tube tube 1 of such a radiator to cool the refrigerant. The side surface of the core 4 is reinforced by a side plate (not shown).

The composite material of the present invention is used for any one or all of the tube 1, the fins 2, and the header plate 3. For example, the fin 2 is a thin plate having a thickness of about 0.1 mm, and the tube 1 is a thin plate having a thickness of about 0.2 mm.
A composite material (brazing sheet) having a thickness of up to 0.4 mm and subjected to electric resistance welding in a cylindrical shape with the sacrificial anode material inside (coolant side) is used. The header plate 3 has a thickness of 1.0 to
The same material as the 1.3 mm tube is used.

[0023]

Embodiment 1 A first embodiment of the present invention will be described in detail with reference to Tables 1 and 2. Table 1 shows the composition of the aluminum alloy of the core material, and Table 2 shows the composition of the alloy of the sacrificial anode material and the test results. An alloy of a core material and a sacrificial anode material having the compositions shown in Tables 1 and 2 was cast in a mold, and the core material was finished to a thickness of 40 mm by facing, and the sacrificial anode material was thickened by hot rolling after facing. 5mm
Finished. As the brazing material, a JIS-4343 alloy was cast in a mold, and the surface was cut to a thickness of 5 mm by hot rolling. Three pieces of the brazing material, the core material, and the sacrificial anode material are stacked in this order, and 5
Hot-rolled at 00 ° C. to produce a three-layer clad material, then cold-rolled to a thickness of 0.29 mm, intermediately annealed at 340 ° C. for 2 hours, and further cold-rolled to a thickness of 0.
A 25 mm H14 brazing sheet was obtained. The clad ratio of the brazing sheet in the composite material of the sacrificial material and the brazing material is 10%.

Each of the obtained brazing sheets was subjected to a corrosion resistance test in an acidic environment and an alkaline environment. The test method is shown below. [Corrosion resistance test under acidic environment] Each brazing sheet was subjected to ERW processing to form a tube tube (length: 500 mm, cross section width: 16 mm, height: 2 m)
m), a heat exchanger having the structure shown in FIG. 1 is assembled using the tube tubes, a corrosive liquid is circulated through the tube tubes of the heat exchanger for a predetermined period, and after the circulation, the tube tubes are randomly discharged from the heat exchanger. 10 samples were taken, and the pitting depth from the inner surface side of the tube material was measured. The pit depth was measured by the depth of focus method using an optical microscope. The maximum pit depth was indicated in units of 10 μm by rounding off the measured value.

The fins include Al-0.5 wt% Si-
A thin plate made of 1.0 wt% Mn-2.0 wt% Zn alloy and having a thickness of 0.1 mm, which was corrugated, was used. Header plate and side plate are both JI
A core material obtained by adding 0.15 wt% of Mg to the S-3003 alloy has a brazing material of JIS-4343 alloy on one side and an Al on the other side.
A sacrificial anode material of -1.5 wt% alloy was clad at a rate of 10
% Of an aluminum alloy composite material having a thickness of 1.2 mm. The circulation condition of the etching solution is Cl ion 1
An aqueous solution (pH 3) containing 95 ppm, 60 ppm of SO ₄ ²⁻ ions, 1 ppm of Cu ²⁺ ions, and 30 ppm of Fe ³⁺ ions was used as a corrosive liquid, and was used at 88 ° C. for 8 hours and at room temperature for 16 hours.
It was circulated alternately for 6 months.

[Corrosion Resistance Test in Alkaline Environment] In a tube tube of a heat exchanger having the same structure as that used in the corrosion resistance test, 195 ppm of Cl ^- ion and SO ₄ ^2- ion 6 were added.
0 ppm, Cu ²⁺ ion 1 ppm, Fe ³⁺ ion 3
A solution adjusted to pH 11 by adding NaOH to an aqueous solution containing 0 ppm was used as a corrosive solution, and was used at 88 ° C. for 8 hours and at room temperature for 16 hours.
It was circulated alternately for 6 months. After the circulation, the pit depth from the inner surface of the tube was measured in the same manner as in the corrosion test under an acidic environment. Table 1 shows the results of the corrosion resistance test under acidic and alkaline environments. In the column of maximum pit depth, those having a maximum pit depth of less than 100 μm are marked with “○”, and the maximum pit depth is 100 μm.
Those having m or more are indicated by x.

[Table 1]

[Table 2]

As is clear from Tables 1 and 2, No. 1 of the present invention example. Nos. 1 to 17 exhibited excellent corrosion resistance at a pit depth of 100 μm or less under both acidic and alkaline corrosion environments. On the other hand, in the comparative examples (Nos. 18 to 23) and the conventional examples (No. 24) whose alloy compositions are outside the range of the present invention, the corrosion resistance was reduced in either an acidic or alkaline corrosive environment. Comparative Example No. In No. 18, since the Cu content of the core material is small, the number of defective portions of the coating film is small under an alkaline corrosive environment, and corrosion is concentrated on the defective portions and the corrosion depth is deep. Comparative Example No. In No. 19, the Cu content of the core material was large, the number of defects in the film was large under an alkaline corrosive environment, the protective action of the film was lost, and the pit depth was deep. Comparative Example No.
In No. 20, since the Zn content of the sacrificial material is small, the sacrificial anticorrosion effect in an acidic corrosion environment is insufficient, and the pitting depth is deep. Comparative Example No. In No. 21, since the Zn content of the sacrificial material was too large, the material was broken during rolling, and an aluminum alloy composite material could not be produced. Comparative Example No. In No. 22, the core material contained a large amount of Si, and thus the self-corrosion resistance of the core material was reduced. Comparative Example No. No. 23 could not be formed as a tube tube because the Mn content of the core material was too large. Also,
Conventional example No. In No. 24, since the core material contained 0.15% of Cu, many defective portions of the film were generated in an alkaline corrosive environment, and the corrosion resistance was poor.

[0028]

Embodiment 2 A second embodiment of the present invention will be described in detail with reference to Tables 3 and 4. Table 3 shows the composition of the aluminum alloy of the core material, and Table 4 shows the composition of the alloy of the sacrificial anode material and the test results. An alloy of a core material and a sacrificial anode material having the compositions shown in Tables 3 and 4 was cast into a mold, and the core material was finished to a thickness of 40 mm by facing, and the sacrificial anode material was thickened by hot rolling after facing. 5mm
Finished. As the brazing material, a JIS-4343 alloy was cast in a mold, and the surface was cut to a thickness of 5 mm by hot rolling. Three pieces of the brazing material, the core material, and the sacrificial anode material are stacked in this order, and 5
Hot-rolled at 00 ° C. to produce a three-layer clad material, then cold-rolled to a thickness of 0.29 mm, intermediately annealed at 340 ° C. for 2 hours, and further cold-rolled to a thickness of 0.
A 25 mm H14 brazing sheet was obtained. The clad ratio of the brazing sheet in the composite material of the sacrificial material and the brazing material is 10%.

Each of the obtained brazing sheets was subjected to a tensile test and a corrosion resistance test in an acidic environment and an alkaline environment. The test method is shown below. [Tensile Test] Each of the brazing sheets was processed into a JIS No. 5 tensile test piece, heat-treated at 600 ° C. for 30 minutes in N ₂ gas as heating equivalent to brazing, and then a tensile test was performed. [Corrosion resistance test under acidic environment] Each brazing sheet was subjected to ERW processing to form a tube tube (length: 500 mm, cross-section width: 1).
6 mm, height 2 mm), assembling a heat exchanger having the structure shown in FIG. 1 using this tube tube, circulating a corrosive liquid through the tube tube of this heat exchanger for a predetermined period, and circulating the heat from the heat exchanger. Ten tube tubes were randomly sampled, and the pitting depth from the inner side of the tube material was measured. The pit depth was measured by the depth of focus method using an optical microscope.
The maximum pit depth was indicated in units of 10 μm by rounding off the measured value.

The fins include Al-0.5 wt% Si-
A thin plate made of 1.0 wt% Mn-2.0 wt% Zn alloy and having a thickness of 0.1 mm, which was corrugated, was used. Header plate and side plate are both JI
A core material obtained by adding 0.15 wt% of Mg to the S-3003 alloy has a brazing material of JIS-4343 alloy on one side and an Al on the other side.
A sacrificial anode material of -1.5 wt% alloy was clad at a rate of 10
% Of an aluminum alloy composite material having a thickness of 1.2 mm. The circulating conditions of the etching solution were as follows ^: 195 ppm of Cl ⁻ ions, 60 ppm of SO ₄ ²⁻ ions, Cu ²⁺
An aqueous solution (pH 3) containing 1 ppm of ions and 30 ppm of Fe ³⁺ ions was used as a corrosive liquid, and the solution was treated at 88 ° C. for 8 hours and at room temperature for 1 hour.
It was circulated alternately for 6 hours for 6 months.

[Corrosion Resistance Test in Alkaline Environment] In a tube tube of a heat exchanger having the same structure as that used in the corrosion resistance test, 195 ppm of Cl ^- ion and SO ₄ ^2- ion 6 were added.
0 ppm, Cu ²⁺ ion 1 ppm, Fe ³⁺ ion 3
A solution adjusted to pH 11 by adding NaOH to an aqueous solution containing 0 ppm was used as a corrosive solution, and was used at 88 ° C. for 8 hours and at room temperature for 16 hours.
It was circulated alternately for 6 months. After the circulation, the pit depth from the inner surface of the tube was measured in the same manner as in the corrosion test under an acidic environment. Table 1 shows the results of the tensile test and the corrosion resistance test under acidic and alkaline environments. In addition, the result of the tensile test
If the tensile strength is 100 MPa or more, ○, the tensile strength is 1
Those having a value of less than 00 MPa were indicated as x in the column of tensile strength. The results of the corrosion test are as follows: those with a maximum pit depth of less than 100 μm are evaluated as good, and those with a maximum pit depth of 100 μm or more are evaluated as x.
In the column of maximum pit depth.

[Table 3]

[Table 4]

As is clear from Tables 3 and 4, No. 1 of the present invention example. Nos. 31 to 44 exhibited excellent corrosion resistance at a pit depth of 100 µm or less under both acidic and alkaline corrosion environments. On the other hand, the comparative examples (Nos. 45 to 51) and the conventional examples (No. 52) in which the alloy compositions are outside the range of the present invention have reduced corrosion resistance in either an acidic or alkaline corrosive environment, or have a tensile strength of 100 MPa or less. Was inferior.
Comparative Example No. 45 is low in Cu content of the core material,
Under an alkaline corrosive environment, there are few defective portions of the film, and corrosion is concentrated on the defective portions and the corrosion depth is deep. Comparative Example N
o. In No. 46, the Cu content of the core material is large, the number of defective portions of the film is large under an alkaline corrosive environment, the protective effect of the film is lost, and the pitting depth is deep. Comparative Example No. In No. 47, since the Zn content of the sacrificial material is small, the sacrificial anticorrosion effect in an acidic corrosive environment is insufficient, and the pitting depth is deep. Comparative Example No. In No. 48, since the Zn content of the sacrificial material was too large, it was broken during rolling, and an aluminum alloy composite could not be produced. Comparative Example No. In No. 49, since the core material contains a large amount of Si, the self-corrosion resistance of the core material was reduced. Comparative Example No. 50 is because the Mn content of the core material is too large,
It could not be molded as a tube. Comparative Example No. 51
Indicates that the Mn content of the sacrificial anode material is out of the composition range of the present invention, and the corrosion resistance is good under both acidic and alkaline corrosion environments, but the tensile strength is low. Also, in Conventional Example No. In No. 52, since the core material contained 0.15% of Cu, many defects were found in the film under an alkaline corrosive environment, and the corrosion resistance was poor.

[0033]

As described above, according to the highly corrosion-resistant aluminum alloy composite material of the present invention, sufficient corrosion resistance can be obtained in both acidic and alkaline corrosion environments, and excellent corrosion resistance, strength, and forming process. It has an industrially remarkable effect as an aluminum alloy composite material for heat exchangers.

[Brief description of the drawings]

FIG. 1 (a) is a heat exchanger (radiator) for an automobile
And (b) is an enlarged cross-sectional view taken along the line AA of (a).

[Explanation of symbols]

 1 tube tube 2 corrugated fin 3 header plate 4 core 5 packing 6, 7 resin tank

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁶ identifications FI F28F 21/08 F28F 21/08 D B // C22F 1/00 627 C22F 1/00 627 640 640A 641 641A 651 651A 683 683 685 685 686 686Z

Claims (10)

[Claims] 1. Si: 0.05 to 1.2 wt%, Fe:
0.05-0.8 wt%, Cu: 0.003-0.01
Less than wt%, Mn: 0.5 to 2.0 wt%, aluminum alloy consisting of the remaining Al and unavoidable impurities is used as a core material, and Zn: 2.0 to 6.0 wt% is contained on one surface of the core material. A high corrosion-resistant aluminum alloy composite material, characterized in that an aluminum alloy comprising the remaining Al and inevitable impurities is clad as a sacrificial anode material. 2. Si: 0.05 to 1.2 wt%, Fe:
0.05-0.8 wt%, Cu: 0.003-0.01
wt.%, Mn: 0.5 to 2.0 wt.%, and an aluminum alloy containing the balance of Al and unavoidable impurities as a core material, and Zn: 2.0 to 6.0 wt.
Mn: A highly corrosion-resistant aluminum alloy composite material containing 0.5 to 2.0 wt% and clad as an sacrificial anode material with an aluminum alloy containing the balance of Al and inevitable impurities. 3. Si: 0.05 to 1.2 wt%, Fe:
0.05-0.8 wt%, Cu: 0.003-0.01
wt%, Mn: 0.5-2.0 wt%, Cr: 0.01-0.3 wt%, Zr: 0.01-
0.3 wt%, Ti: 0.01-0.3 wt%, Mg
Contains one or more of 0.2 wt% or less,
An aluminum alloy consisting of the remaining Al and unavoidable impurities is used as a core material, and Zn is 2.0 to 6.0 wt% on one surface of the core material.
A high corrosion-resistant aluminum alloy composite material, characterized in that aluminum alloy comprising the balance of Al and inevitable impurities is clad as a sacrificial anode material. 4. Si: 0.05 to 1.2 wt%, Fe:
0.05-0.8 wt%, Cu: 0.003-0.01
wt%, Mn: 0.5-2.0 wt%, Cr: 0.01-0.3 wt%, Zr: 0.01-
0.3 wt%, Ti: 0.01-0.3 wt%, Mg:
Contains one or more of 0.2 wt% or less,
An aluminum alloy consisting of the remaining Al and unavoidable impurities is used as a core material, and Zn: 2.0 to 6.0 wt.
%, Mn: 0.5 to 2.0 wt%, and a high corrosion-resistant aluminum alloy composite material characterized by being clad as an sacrificial anode material with an aluminum alloy comprising the balance of Al and inevitable impurities. 5. The core aluminum alloy of the highly corrosion-resistant aluminum alloy composite according to claim 1,
B: An aluminum alloy composite material having high corrosion resistance, characterized by being an aluminum alloy containing 0.05 wt% or less. 6. The high corrosion-resistant aluminum according to claim 1, wherein an Al-Si alloy or an Al-Si-Zn alloy is clad on the other surface of the core material as a brazing material. Alloy composite. 7. The highly corrosion-resistant aluminum alloy composite according to claim 1, wherein the highly corrosion-resistant aluminum alloy composite is used for a heat exchanger. 8. A heat exchanger comprising a tube tube, a fin, or a header plate using the high corrosion resistant aluminum alloy composite material according to claim 1. Description: 9. The method according to claim 1, wherein a sacrificial anode material is superposed on one surface of the core material, hot-rolled and cold-rolled, and if necessary, intermediately annealed after cold-rolling and then cold-rolled.
5. The method for producing a highly corrosion-resistant aluminum alloy composite according to any one of the above items 5. 10. A hot rolling and cold rolling method in which a sacrificial anode material is laminated on one side of the core material and a brazing material is laminated on the other side, and if necessary, intermediate annealing is performed after cold rolling and then cold rolling is performed. The method for producing a highly corrosion-resistant aluminum alloy composite according to claim 6, characterized in that: