JPH11241136A - High corrosion resistant aluminum alloy, clad material thereof, and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high corrosion resistant aluminum alloy and a high corrosion resistant aluminum alloy clad material for heat exchanger, capable of obtaining sufficient corrosion resistance under an alkaline corrosive environment. SOLUTION: This high corrosion resistant aluminum alloy has 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. Further, the high corrosion resistant aluminum alloy clad material is constituted by using the high corrosion resistant aluminum alloy as a core material and cladding one side of this core material with an Al-Si alloy as a brazing filler metal. The high corrosion resistant aluminum alloy or clad material is excellent as a material for heat exchanger use and can be used for tube material, header plate material, etc., of 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, a highly corrosion-resistant aluminum alloy composite material and a method for producing the composite material, and more particularly to an alkaline refrigerant suitable for an exchanger produced by brazing. The present invention relates to a highly corrosion-resistant aluminum alloy, a highly corrosion-resistant aluminum alloy composite material, and a method for producing the composite material.

[0002]

2. Description of the Related Art Conventionally, a radiator of a heat exchanger, for example, a heat exchanger for an automobile, has fins 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 the assembly, a resin tank is attached to the header plate via packing, and the refrigerant is cooled by passing the refrigerant through a tube tube of such a radiator. For the fins of such a heat exchanger, 1.5 wt.
% Of the alloy is used as the core material, and Al-Si
A thin plate clad with a brazing material is used. The tube tube is made of JIS-3003 alloy or JIS-32
The one obtained by subjecting the 03 alloy to electric resistance welding in a cylindrical shape is used.
The header plate is made of JIS-3003 alloy or JIS-3203 alloy as a core material, and Al-S
An aluminum alloy composite material in which an i-type brazing material is clad is used.

[0003]

In the heat exchanger, it is desired to reduce the thickness of the member in order to reduce the weight, and to improve the corrosion resistance of the member in order to reduce the thickness of the member. Also,
In recent years, since alkaline refrigerants are widely used,
As an aluminum alloy material for a tube tube, a material that can withstand 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.

[0004] In view of the above, the present inventors have conducted intensive studies and found an aluminum alloy having excellent corrosion resistance in an alkaline corrosive environment, and have further studied to complete the present invention. An object of the present invention is to provide a highly corrosion-resistant aluminum alloy and a highly corrosion-resistant aluminum alloy composite material that can obtain sufficient corrosion resistance in an alkaline corrosion environment.

[0005]

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
A highly corrosion-resistant aluminum alloy containing less than 0.1 wt%, Mn: 0.5 to 2.0 wt%, and the balance of Al and unavoidable impurities. Further, the present invention (the invention described in claim 2) is characterized in that 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,
This is a highly corrosion-resistant aluminum alloy comprising a balance of Al and inevitable impurities.

Further, the present invention (the invention described in claim 3)
A highly corrosion resistant aluminum alloy characterized by further containing B: 0.05 wt% or less in the above aluminum alloy. That 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%, B: 0.05 wt% or less, the balance Al
And a high corrosion-resistant aluminum alloy characterized by being composed of aluminum alloy and unavoidable impurities. Also, Si: 0.05 to 1.2 w
t%, Fe: 0.05 to 0.8 wt%, Cu: 0.00
3 to less than 0.01 wt%, Mn: 0.5 to 2.0 wt%
, Cr: 0.01-0.3 wt%, 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 balance Al
And a high corrosion-resistant aluminum alloy characterized by being composed of aluminum alloy and unavoidable impurities.

Further, the present invention (the invention described in claim 4) provides
The high corrosion-resistant aluminum alloy according to any one of claims 1, 2, and 3 is used as a high corrosion-resistant aluminum alloy material for a heat exchanger.
For example, it is used for a tube material, a header plate, a fin material and the like of a heat exchanger.

Further, the present invention (the invention described in claim 5) provides
The high corrosion-resistant aluminum alloy described above (in any one of claims 1, 2 and 3) is used as a core material, and Al-
A highly corrosion-resistant aluminum alloy composite material characterized by being clad with a Si-based alloy or an Al-Si-Zn-based alloy as a brazing material. That is, 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%
%, A high corrosion-resistant aluminum alloy consisting of the balance of Al and unavoidable impurities is used as a core material, and Al-
A highly corrosion-resistant aluminum alloy composite material characterized by being clad with a Si-based alloy or an Al-Si-Zn-based alloy as a brazing material. Also, Si: 0.05 to 1.2 wt
%, Fe: 0.05 to 0.8 wt%, Cu: 0.003%
~ 0.01wt%, Mn: 0.5 ~ 2.0wt%, Cr: 0.01 ~ 0.3wt%, Zr:
0.01-0.3wt%, Ti: 0.01-0.3wt
%, Mg: one or more of 0.2 wt% or less, a high corrosion-resistant aluminum alloy containing Al and unavoidable impurities as a core material, and Al-S on one surface of the core material.
A highly corrosion-resistant aluminum alloy composite material characterized by being clad with an i-based alloy or an Al-Si-Zn-based alloy as a brazing material. Also, 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%, B: 0.05 wt% or less, and the balance A
and a core material made of a highly corrosion-resistant aluminum alloy comprising unavoidable impurities, and an Al-Si alloy or A
A highly corrosion-resistant aluminum alloy composite material characterized by cladding an l-Si-Zn-based alloy as a brazing material.
Further, Si: 0.05 to 1.2 wt%, Fe: 0.05
0.8 to 0.8 wt%, Cu: 0.003 to less than 0.01 wt%, Mn: 0.5 to 2.0 wt%, Cr: 0.
01-0.3 wt%, Zr: 0.01-0.3 wt%,
One or more of Ti: 0.01 to 0.3 wt%, Mg: 0.2 wt% or less, and B: 0.0
The core material is a high corrosion-resistant aluminum alloy containing 5 wt% or less, the balance being Al and unavoidable impurities, and one side of the core material is clad with an Al-Si alloy or an Al-Si-Zn alloy as a brazing material. Highly corrosion resistant aluminum alloy composite material.

Further, the present invention (the invention according to claim 6)
Is characterized in that the high corrosion-resistant aluminum alloy composite material (described in claim 5) is used as a high corrosion-resistant aluminum alloy composite material for a heat exchanger. For example, it is used for a tube material, a header plate, a fin material and the like of a heat exchanger. Further, the present invention (the invention according to claim 7) provides a tube tube using the high corrosion-resistant aluminum alloy material described above (claim 4) or the high corrosion-resistant aluminum alloy composite material described above (claim 6). , A fin, or a header plate.

The present invention (the invention according to claim 8)
Is characterized in that a brazing material is overlapped on one side of a core material, hot-rolled, cold-rolled, or subjected to intermediate annealing after cold-rolling and then to cold-rolling. This is a method for producing a corrosion-resistant aluminum alloy composite. That is, the brazing material is superimposed on one surface of the core material and hot-rolled and cold-rolled, wherein the brazing material is hot-rolled and cold-rolled.
A method for producing a high corrosion-resistant aluminum alloy composite material,
The high corrosion-resistant aluminum alloy composite according to claim 5 or 6, wherein a brazing material is overlapped on one surface of the core material, hot-rolled and cold-rolled, then intermediately annealed and then cold-rolled. It is a method of manufacturing a material.

[0011]

The aluminum alloy of the present invention has sufficient corrosion resistance even in an alkaline corrosive environment, and is a highly corrosion-resistant aluminum alloy suitable for heat exchangers. Regarding the alloy composition of the aluminum alloy of the present invention, the significance of the added elements and the reasons for limiting the composition range will be described. In the aluminum alloy material of the present invention, the most important component for imparting sufficient corrosion resistance under an alkaline corrosion environment is Cu.
Therefore, its content becomes a problem. 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 film.

As a result of examining the formation of film defects in an alkaline corrosion environment, it was found that after Cu in the aluminum alloy was dissolved in the alkali corrosion environment, the Cu was reprecipitated on the surface of the aluminum alloy to form a film defect. By controlling the content of Cu in the alloy, the number of film defects in an alkali corrosive environment can be controlled, whereby the corrosion resistance in an alkali corrosive environment can be improved. By reducing the content of Cu in the aluminum alloy to less than 0.01 wt%, defects in the aluminum hydroxide film are reduced, and the protective effect of the film on the underlying aluminum can be exerted. Further, the content of Cu in the aluminum alloy is set to 0.003 w
By setting it to t% or more, it is possible to create an appropriate number of defective portions in the coating and prevent the occurrence of deep pitting corrosion due to concentration of corrosion at the defective portions of the coating. As described above, the content of Cu in the aluminum alloy material is set to 0.003 to 0.01 wt%.
Specify less than. Desirable Cu content is 0.003 to
0.008 wt%. The effect of Cu is as follows:
Even if Fe, Mn, Cr, Zr, Ti, Mg, B, etc. are included within the scope of the present invention, a sufficient effect can be obtained.

[0013] Si forms a solid solution in the matrix after brazing and contributes to the improvement of strength. Si content of 0.05 to
The reason for defining the content to be 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%, Si precipitates alone and the self-corrosion resistance of the aluminum alloy material is reduced. That's why. 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 aluminum alloy material fine, and preventing cracking during forming. The reason for defining the Fe content to be 0.05 to 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 aluminum alloy material is reduced. This is because The desirable content of Fe is 0.05 to 0.3 wt%. Mn distributes a fine intermetallic compound in the alloy and improves the strength without deteriorating the corrosion resistance. Mn content of 0.5 to
The reason why the content is defined as 2.0 wt% is that if the content is less than 0.5 wt%, the effect cannot be sufficiently obtained, and if the content is more than 2.0 wt%, manufacturing workability deteriorates and the yield decreases. The desirable content of Mn is 0.5 to 1.5 wt%.

Next, elements Cr, Zr, Ti, and Mg to be added as selective elements will be described. Cr, Z
r, Ti, and Mg contribute to strength improvement. Cr,
If the content of each of Zr and Ti is less than 0.01 wt%, the effect cannot be sufficiently obtained, and if it exceeds 0.3 wt%, casting cracks may occur. Each desirable content is 0.08 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 added contributes to refinement of the ingot structure, and its content is desirably 0.05 wt% or less. Further, other unavoidable impurity elements may be contained as long as each is 0.05 wt% or less.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The aluminum alloy of the present invention has a sufficient corrosion resistance even in an alkaline corrosive environment and is suitable for heat exchangers.
It can be used as an aluminum alloy composite material in which an l-Si alloy or an Al-Si-Zn alloy is clad with a brazing material. Specifically, it is used for a tube material, a header plate, a fin material, etc. of a heat exchanger. For example, as a brazing material of an Al-Si alloy, JIS-4
343 alloy, JIS-4045 alloy, JIS-4004
An alloy or the like is used.

The highly corrosion-resistant aluminum alloy of the present invention is a cold-work hardened material which is hot-rolled and cold-rolled, and is hot-rolled, cold-rolled, then annealed, and then cold-rolled. It is a cold work hardening material. Further, the high corrosion-resistant aluminum alloy composite material is obtained by cladding a brazing material on one surface of a core material of a high corrosion-resistant aluminum alloy having a specific composition of the present invention, and specifically, laminating the brazing material on one surface of the core material, hot rolling and pressing. And cold-rolled. Further, a brazing material is clad on one side of the core material, cold-rolled, subjected to intermediate annealing, and then further cold-rolled.

The highly corrosion-resistant aluminum alloy or composite material of the present invention is used for a heat exchanger, for example, a heat exchanger (radiator) for automobiles, a heater, a cooler, and the like. Fig. 1 shows an example of a heat exchanger (radiator) for automobiles
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). For the tube tube 1, the fin 2, or the header plate 3, a bare material or a composite material of the high corrosion-resistant aluminum alloy of the present invention is used.

For example, the fin 2 is a composite thin plate having a thickness of about 0.1 mm in which a high corrosion-resistant aluminum alloy is used as a core material and one surface of which is clad with an Al-Si brazing material. The tube tube 1 used is a tube that has been subjected to electric resistance welding. The header plate 3 is made of an aluminum alloy composite material having a thickness of 1.0 to 1.3 mm in which a high corrosion-resistant aluminum alloy is used as a core material and an Al-Si brazing material is clad on one surface.

[0019]

Embodiments of the present invention will be described below in detail with reference to Tables 1 and 2. Alloys having the compositions shown in Table 1 (Examples of the present invention) and Table 2 (Comparative Examples, Conventional Examples) were cast into molds, and after face milling, hot rolling and cold rolling were performed to obtain a thickness of 0.29 mm, and 340 ° C. , And then cold-rolled to a thickness of 0.1 mm.
A 25 mm aluminum alloy material of H14 was obtained. The obtained aluminum alloy materials were subjected to a corrosion resistance test in an alkaline environment. The test method is shown below. Each aluminum alloy material is subjected to ERW processing to form a tube tube (length 500 mm, cross section width 16 mm, height 2 mm),
Using this tube tube, a heat exchanger having the structure shown in FIG. 1 is assembled, a corrosive liquid is circulated through the tube tube of this heat exchanger for a predetermined period, and after the circulation, 10 tube tubes are randomly sampled from the heat exchanger. Then, the pit 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 core material made of an alloy of 1.0 wt% Mn-2.0 wt% Zn and a corrugated thin plate having a thickness of 0.1 mm clad on both sides with a brazing material of JIS-4343 alloy were used. The header plate and the side plate are each a 1.2 mm thick aluminum alloy in which a brazing material of JIS-4343 alloy is clad at a cladding ratio of 10% on one surface of a core material obtained by adding 0.15 wt% of Mg to JIS-3003 alloy. A composite was used. The circulating conditions of the etchant are as follows:
Cl ^- ions 195ppm, _SO ^{4 2-} ions 60
ppm, Cu ²⁺ ion 1 ppm, Fe ³⁺ ion 30
A solution adjusted to pH 11 by adding NaOH to an aqueous solution containing ppm was used as a corrosive solution and circulated alternately at 88 ° C. for 8 hours and at room temperature for 16 hours for 6 months. Table 1 shows the results of the corrosion resistance test in an alkaline environment. In the column of maximum pit depth, those having a maximum pit depth of less than 100 μm are indicated by ○, and those having a maximum pit depth of 100 μm 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 19 had excellent pitting depth of 100 μm or less in an alkaline corrosive environment and exhibited excellent corrosion resistance. On the other hand, a comparative example (No.
0-23) and the conventional example (No. 24) suffered from a problem that the corrosion resistance in an alkaline corrosive environment was reduced or that a tube tube could not be manufactured. Comparative Example No. In No. 20, since the Cu content of the aluminum alloy 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. 21
Has a high Cu content in the aluminum alloy material, many defects in the film in an alkaline corrosion environment, the protective effect of the film has disappeared, and the pitting depth has become deep. Comparative Example No. 22
Is because the Mn content of the aluminum alloy material is too large,
It could not be molded as a tube. Comparative Example No. 23
Since the core material had too much Si content, the self-corrosion resistance of the aluminum alloy material was inferior. Also, in Conventional Example No. 24
Since the core material contained 0.15% of Cu, the film had many defective portions in an alkaline corrosive environment and had poor corrosion resistance.

[0022]

As described above, according to the aluminum alloy and the composite material of the present invention, excellent corrosion resistance can be obtained in an alkaline corrosion environment.
In addition, it has excellent corrosion resistance, strength and moldability, and has industrially remarkable effects for use in 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

Continuation of the front page (51) Int.Cl. ⁶ identification code FI C22F 1/00 627 C22F 1/00 627 651 651A 683 683 686 686A 1/04 1/04 B F28F 19/06 F28F 19/06 Z 21/08 21/08 A

Claims (8)

[Claims] 1. Si: 0.05 to 1.2 wt%, Fe:
0.05-0.8 wt%, Cu: 0.003-0.01
A highly corrosion-resistant aluminum alloy containing less than 0.1 wt%, Mn: 0.5 to 2.0 wt%, and the balance being Al and unavoidable impurities. 2. 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,
A highly corrosion-resistant aluminum alloy comprising a balance of Al and inevitable impurities. 3. A highly corrosion-resistant aluminum alloy, further comprising B: 0.05% by weight or less in the aluminum alloy according to claim 1. 4. The high corrosion-resistant aluminum alloy according to claim 1, wherein the high corrosion-resistant aluminum alloy is used as a high corrosion-resistant aluminum alloy material for a heat exchanger. 5. A core material comprising the high corrosion-resistant aluminum alloy according to claim 1, and an Al-Si alloy or an Al-Si-Zn alloy on one surface of the core material. High corrosion resistance aluminum alloy composite material characterized by being clad. 6. The high corrosion-resistant aluminum alloy composite according to claim 5, wherein the high corrosion-resistant aluminum alloy composite is used as a high corrosion-resistant aluminum alloy composite for a heat exchanger. 7. A high-corrosion-resistant aluminum alloy material according to claim 4 or a high-corrosion-resistance aluminum alloy composite material according to claim 6, wherein one or all of a tube tube, a fin, and a header plate are formed. Characterized heat exchanger. 8. The method according to claim 5, wherein a brazing material is overlapped on one surface of the core material, hot-rolled, cold-rolled, or subjected to intermediate annealing and cold-rolling as appropriate after cold-rolling. Manufacturing method of high corrosion resistant aluminum alloy composite.