JP2006249482A - Aluminum alloy fin material for heat exchanger and heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy fin material for a heat exchanger excellent in strength characteristic, brazability and self-corrosion-resistance, and a heat exchanger. <P>SOLUTION: A composition consisting of, by weight, >0.6 to <1.2% Si, >1.5 to 2.5% Mn, >0.15 to 1% Ni, 0.01 to <0.03% Mg, ≤0.5% Fe, >1 to 5% Zn and the balance Al with inevitable impurities is provided as an aluminum alloy fin material for a heat exchanger, whereby the brazability of the fin material at the time of assembling a heat exchanger by brazing is improved and a high strength fin material excellent in self-corrosion-resistance is obtained; therefore the aluminum alloy fin material for a heat exchanger can be reduced in thickness and weight and the reliability of the fin material and the resulting heat exchanger is improved. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aluminum alloy fin material for a heat exchanger used in an aluminum alloy heat exchanger manufactured by a brazing method and a heat exchanger provided with the same.

In recent years, with the reduction in weight of automobiles, heat exchangers for automobiles are also required to be reduced in weight, and in order to cope with this, thinner fin materials and higher strength are required.
Conventionally, 1000 series or 3000 series aluminum alloys have been used as fin materials for heat exchangers. However, the fin material manufactured from the above-described aluminum alloy does not necessarily have sufficient strength after brazing, and there is a possibility that the strength may be insufficient when the fin material is thinned.

  In order to improve the strength of the brazed fin material, an aluminum alloy fin material for a heat exchanger made of an aluminum alloy in which Zn or the like is added to an Al—Mn—Si—Ni system has been proposed (for example, Patent Document 1). .

  Further, an aluminum fin material for a heat exchanger has been proposed in which, in an aluminum alloy fin material having a plate thickness of 0.1 mm or less, the size of an intermetallic compound of 90% or more is set to a maximum value of 5 μm or less (for example, Patent Documents). 2).

Further, the material of the fin material is Cu: 0.10 to 0.25 wt%, Zn: 2.0 to 3.5%, Si: 0.6 to 1.5%, and Mn: 0.5 to 2.0. %, The balance Al and unavoidable impurities, and when the Cu content (%) is [Cu] and the Zn content (%) is [Zn], [Cu] and [Zn] When the relationship is 0.10 ≦ [Cu] ≦ 0.15 ([Zn] −2) / [Cu] ≦ 8 and 0.15 <[Cu] ≦ 0.25 ([Zn] −3) / [Cu] ≦ 4/3 has been proposed for an aluminum alloy fin material for a heat exchanger (for example, Patent Document 3).
JP 2004-59939 A JP 2001-226730 A Japanese Patent No. 3521105

The aluminum alloy fin material for heat exchangers described in Patent Document 1 is superior in strength after brazing as compared to the conventional fin material because it is composed of the above-described component composition.
However, in the configuration of the aluminum alloy fin material for heat exchanger of Patent Document 1, since the Ni content is more than 1% and not more than 5%, when the Mn content is set high, the Al content is reduced during the casting of the fin material. The -Mn-Ni intermetallic compound is likely to be coarsened, and the workability of the fin material may be reduced.

The aluminum alloy fin material for heat exchangers described in Patent Document 2 prevents fatigue failure by setting the intermetallic compound size to 5 μm at the maximum.
However, in the structure of the aluminum alloy fin material for heat exchangers of Patent Document 2, the amount of Si-based low-melting compound precipitated at the grain boundaries of the fin material increases due to the heat treatment during brazing, and the grain boundary Local melting tends to occur, and wax erosion may increase.

The aluminum alloy fin material for heat exchangers described in Patent Document 3 has improved corrosion resistance and strength by satisfying the above-described element amount definition and Cu and Zn addition amount defining formula.
However, in the configuration of the aluminum alloy fin material for heat exchanger of Patent Document 3, the amount of Si-based low-melting compound precipitated at the grain boundary of the fin material is increased by the heat treatment during brazing, and the grain boundary is Local melting tends to occur, and wax erosion may increase.

  Regarding brazing properties of aluminum alloy fin materials for heat exchangers, with the recent thinning of fin materials, brazing of the fin materials during brazing has become a major problem. When the Al—Si brazing used for joining the tube material erodes the fin material, the fin material is buckled, which may lead to a decrease in durability and heat exchange efficiency of the heat exchanger. For this reason, the fin material which is excellent in brazing property and brazing corrosion resistance has been demanded.

  This invention is made | formed in view of the said situation, and it aims at providing the aluminum alloy fin material for heat exchangers and heat exchangers which were excellent in intensity | strength characteristic, brazing property, and self-corrosion resistance.

The present applicant has repeatedly studied to obtain an aluminum alloy fin material for a heat exchanger having excellent strength characteristics, brazing properties, and self-corrosion properties, and to obtain an aluminum alloy fin material for a heat exchanger having the following configuration. It came.
(1) Invention according to claim 1 By weight%: Si: more than 0.6% and less than 1.2%, Mn: more than 1.5% and not more than 2.5%, Ni: more than 0.15% and not more than 1%, Mg: 0.01% or more and less than 0.03%, Fe: 0.5% or less, Zn: more than 1% and 5% or less, the balance being aluminum and inevitable impurities, aluminum for heat exchangers Alloy fin material.
(2) Invention of Claim 2 The said aluminum alloy fin material for heat exchangers is further Zr: 0.05% or more and 0.3% or less, Cr: 0.05% or more and 0.3% or less, Ti: 0.00. The aluminum alloy fin for heat exchanger according to claim 1, comprising at least one of 05% to 0.3% and V: 0.05% to 0.3%. Wood.
(3) Invention according to claim 3 The aluminum alloy fin material for heat exchanger according to claim 1 or 2 is used as a core material, and an Al-Si alloy brazing material is clad on both surfaces of the core material. A featured aluminum alloy fin material for heat exchangers.
(4) Invention of Claim 4 The heat exchanger provided with the aluminum alloy fin material for heat exchangers in any one of Claims 1-3.

In the aluminum alloy fin material for heat exchanger of the present invention, by weight, Si: more than 0.6% and less than 1.2%, Mn: more than 1.5% and less than 2.5%, Ni: more than 0.15% and 1% Hereinafter, Mg: 0.01% or more and less than 0.03%, Fe: 0.5% or less, Zn: more than 1% and 5% or less, and the balance Al and inevitable impurities are contained.
Thereby, the brazing property at the time of assembling the heat exchanger by brazing the fin material is improved, and the fin material having high strength and excellent self-corrosion resistance is obtained.
Therefore, the aluminum alloy fin material for heat exchanger can be made thinner and lighter, and the reliability of the fin material and the heat exchanger is improved.
In the aluminum alloy fin material for a heat exchanger of the present invention, Zr: 0.05% to 0.3%, Cr: 0.05% to 0.3%, Ti: 0.05% to 0.3%. The strength of the fin material is further improved by adopting a constitution containing at least one of 3% or less and V: 0.05% or more and 0.3% or less.
In the heat exchanger equipped with the aluminum alloy fin material for heat exchanger of the present invention, it is possible to further reduce the thickness and weight by adopting the fin material having excellent strength characteristics and brazing properties, and the reliability is improved. To do.

Embodiments of an aluminum alloy fin material for a heat exchanger according to the present invention will be described below.
The aluminum alloy fin material for heat exchanger of the present embodiment (hereinafter sometimes abbreviated as fin material) is Si: more than 0.6% and less than 1.2%, and Mn: more than 1.5%. 5% or less, Ni: more than 0.15% and 1% or less, Mg: 0.01% or more and less than 0.03%, Fe: 0.5% or less, Zn: more than 1% and 5% or less, and the balance Al And inevitable impurities are contained.
Further, if necessary, Zr: 0.05% to 0.3%, Cr: 0.05% to 0.3%, Ti: 0.05% to 0.3%, V: 0.00. It is good also as a structure containing at least 1 or more types within 05% or more and 0.3% or less.
Hereinafter, the reason for limiting the numerical value of the alloy composition of the fin material of the present embodiment will be described.

[Mg]
Magnesium (Mg) easily reacts with a fluoride-based nocollock flux used for the purpose of removing an oxide film of an Al alloy during brazing, and produces a compound such as MgF ₂ to reduce brazing. Further, Mg tends to continuously precipitate a low melting point compound such as Mg ₂ Si continuously at the grain boundary during brazing. At this time, when brazing with a clad material or the like, the molten brazing diffuses into the fin material, so that local melting occurs near the grain boundary and near the grain boundary, and erosion of the solder to the grain boundary of the fin material is likely to occur. Become.
The Mg content is preferably in the range of 0.01% or more and less than 0.03% by weight.
By setting the Mg content in the range of 0.01% or more and less than 0.03%, the amount of low melting point compound precipitated at the grain boundaries during brazing can be greatly reduced, and the fin material brazing Adhesiveness and resistance to wax erosion can be improved.
As a result of intensive studies on the optimum content of Mg fin material by the present applicant for the purpose of improving brazing (brazing erosion resistance), the Mg content is in the range of 0.01% or more and less than 0.03%. In this case, it has been clarified that the brazing property (brazing erosion resistance) is most improved (see Examples described later).
If the Mg content in the fin material is 0.03% or more, the amount and size of the Mg-Si low melting point compound that precipitates at the grain boundaries will greatly increase, and the molten brazing will diffuse during brazing. As a result, local melting is likely to occur, and the erosion of the wax into the grain boundaries of the fin material may increase.
If Mg contained in the fin material is less than 0.01%, the amount of Mg that forms a compound with Si is small, so the amount of Si in a free state increases at the grain boundary. For this reason, the amount of Si-based low-melting compound precipitated at the grain boundaries increases due to the heat treatment during brazing, and local melting of the grain boundaries tends to occur due to diffusion of the molten braze, and the brazing of the fin material to the grain boundaries There is a risk of increased erosion.

[Si]
Silicon (Si) coexists with Mn to produce Al-Mn-Si fine precipitates, and improves the strength after brazing of the fin material and the high temperature buckling resistance during brazing heat.
The Si content is preferably in the range of more than 0.6% and less than 1.2% by weight.
By setting the Si content in the range of more than 0.6% and less than 1.2%, the strength after brazing of the fin material and the high-temperature buckling resistance during brazing addition heat are improved.
If the Si content is 0.6% or less, the amount of precipitation of the low melting point compound can be reduced, but the effect of improving the strength by adding Si is reduced.
If the Si content is 1.2% or more, the melting point of the fin material is lowered, and the fin material may melt during brazing. Further, when the Si content is increased, when the Mg content is in the range of 0.01% or more and less than 0.03%, the amount of precipitation of the low melting point Si-based compound at the grain boundary increases during brazing, There is a possibility that the erosion of the wax into the grain boundary of the fin material may increase.

[Mn]
Manganese (Mn) improves the strength of the aluminum alloy and also produces Al—Mn-based precipitates (Al ₆ Mn) or Al—Mn—Si-based fine intermetallic compounds. Improves strength after brazing and high temperature buckling resistance during brazing heat.
The Mn content is preferably in the range of more than 1.5% to 2.5% by weight.
As described above, by setting the Mg content in the range of 0.01% or more and less than 0.03%, and the Mn content in the range of more than 1.5% to 2.5% or less, the fin material Of Mg-Si and Si low-melting compounds that promote the formation of Mn-Si compounds that contribute to improving the strength of steel and reduce brazing and brazing corrosion resistance at grain boundaries The amount can be reduced.
When the content of Mn is 1.5% or less, the effect of improving the strength by adding Mn becomes small. In addition, since the amount of Mn that forms a compound with Si decreases and Si in a free state increases, the amount of precipitation of a low melting point Si-based compound increases at the grain boundary during brazing, and the fin material There is a possibility that the erosion of the wax into the grain boundary becomes large.
If the Mn content exceeds 2.5%, the intermetallic compound becomes coarse during casting of the fin material, and the workability and various properties of the fin material may be deteriorated.

[Ni]
Nickel (Ni) improves the strength after brazing and the high-temperature buckling resistance during brazing additional heat.
The Ni content is preferably in the range of more than 0.15% and 1% or less by weight.
As described above, the Mg content is 0.01% or more and less than 0.03%, the Mn content is in the range of more than 1.5% and 2.5% or less, and the Ni content is 0.15. By setting the content in the range of more than 1% and 1% or less, the precipitation amount of the low melting point compound on the grain boundary is reduced, the brazing property and the brazing corrosion resistance are improved, and the Al-Mn-Ni-based metal By producing the compound, the strength is improved.
When the Ni content is 0.15% or less, the effect of improving the strength by adding Ni becomes small.
When the Ni content exceeds 1%, when the Mn content is set higher than 1.5% and less than 2.5%, the Al-Mn-Ni intermetallic compound becomes coarse during the casting of the fin material. It is easy and workability may be reduced. Moreover, since the amount of Mn that forms a compound with Si decreases due to an increase in Al-Mn-Ni intermetallic compounds, Si in a free state increases, and at the time of brazing, grain boundaries In addition, since the precipitation amount of the low melting point Si compound increases, the erosion of the wax into the grain boundaries of the fin material may increase.

[Fe]
While iron (Fe) improves the strength of the fin material by dispersion strengthening, it tends to produce coarse intermetallic products, and the intermetallic products become the core of recrystallization. The grains become fine, are susceptible to wax erosion, and the brazeability may be reduced.
For this reason, it is preferable that content of Fe is 0.5% or less by weight%.
By setting the Fe content to 0.5% or less, it is possible to simultaneously improve the strength, brazing property, and brazing corrosion resistance.
When the content of Fe exceeds 0.5%, as described above, the brazing property may be deteriorated.

[Zn]
Zinc (Zn) makes the potential of the fin material base (minus) and gives a sacrificial anode effect.
The Zn content is preferably in the range of more than 1% and 5% or less by weight.
By making the Zn content in the range of more than 1% and not more than 5%, a sufficient sacrificial anode effect can be obtained between the fin material and the tube material.
If the Zn content is 1% or less, a sufficient sacrificial anode effect due to the addition of Zn may not be obtained.
If the Zn content exceeds 5%, the self-corrosion resistance of the fin material may be reduced.
Although it is possible to obtain a sacrificial anode effect by adding In or Sn, when 0.1% or more of In or Sn is added, the self-corrosion resistance of the fin material may be lowered.

[Zr, Cr, Ti, V]
Zirconium (Zr), chromium (Cr), titanium (Ti), and vanadium (V) all improve the strength of the fin material after brazing and the high temperature buckling resistance during brazing additional heat.
The content of Zr, Cr, Ti, V is preferably in the range of 0.05% to 0.3% by weight.
By setting the content of any element of Zr, Cr, Ti, and V to 0.05% or more and 0.3% or less, as described above, the strength after brazing and the resistance to brazing heat High temperature buckling can be improved.
When the content of Zr, Cr, Ti, V is less than 0.05%, the effect of improving the strength after brazing and the high temperature buckling resistance during brazing additional heat is reduced.
If the content of Zr, Cr, Ti, V exceeds 0.3%, workability may be reduced.

  As described above, Zr, Cr, Ti, and V are all elements that improve the strength of the fin material. Therefore, one or more of these elements may be added.

  When manufacturing the fin material of the present embodiment, for example, an aluminum alloy having a composition in the above appropriate range is melted and cast and homogenized. Subsequently, hot rolling, cold rolling, intermediate annealing, and cold rolling are performed to obtain a fin material.

  In addition, you may use the aluminum alloy fin material for heat exchangers of this embodiment as a structure which clad the Al-Si type alloy brazing material on both surfaces of this core material as this core material.

FIG. 1 shows an exploded perspective view of a radiator (heat exchanger) 10 for an automobile as an example in which the aluminum alloy fin material for a heat exchanger of the present invention is used.
In FIG. 1, reference numeral 1 is a fin (fin material), reference numeral 2 is a tube, reference numeral 3 is a header, and reference numeral 4 is a side support. The radiator shown in FIG. 1 is manufactured by integrating the tube 2, the fin 1 and the header 3 by brazing using a fluoride-based flux, and further attaching a resin tank by mechanical joining (caulking).
The brazing heat treatment is preferably performed at about 600 ° C. in a nitrogen gas atmosphere, and the holding time is preferably about 3 minutes. By the heat treatment at this time, various intermetallic compounds are generated in the alloy structure of the fin material, and the strength of the fin material can be improved.

As described above, according to the aluminum alloy fin material for a heat exchanger of the present invention, brazing properties when the heat exchanger is assembled by brazing the fin material due to the inclusion of the element having the above-described composition. In addition, a fin material having high strength and excellent self-corrosion resistance can be obtained.
Therefore, it is possible to reduce the thickness and weight of the fin material, and improve the reliability of the fin material and the heat exchanger.

Below, the Example of the aluminum alloy fin material for heat exchangers concerning this invention is described.
An aluminum alloy fin material for heat exchanger according to the present invention and a conventional fin material (comparative example) according to the present invention were prepared under various component composition conditions shown in the respective examples and comparative examples described later, and various evaluation tests were performed.
Below, the preparation process of a fin material and each evaluation test item are demonstrated.

[Production process]
Using an aluminum alloy ingot having a thickness of 20 mm × length 52 mm × width 125 mm having the composition shown in each of the examples and comparative examples to be described later, after chamfering 1/4 inch per side, homogenized at a predetermined temperature. And hot rolling. Further, after cold rolling to a predetermined plate thickness, intermediate annealing and cold rolling are performed, and the aluminum alloy fin material for heat exchanger according to the present invention having a thickness of 0.05 mm and the conventional fin material (comparative example) ) Was obtained for each component composition.
In addition, about brazing heat processing, after hold | maintaining for 3 minutes at the temperature of 600 degreeC in nitrogen gas atmosphere, it cooled to room temperature (25 degreeC) with the cooling rate of -100 degreeC / min.

[Strength test]
A tensile test piece having a width of 12.5 mm and a length of 180 mm was produced using the fin material according to the present invention obtained in the above production process and the conventional fin material. Using these test pieces as samples, using a Shimadzu AG-GI 10 kn as a tensile tester, and performing a tensile test at a tensile speed of 2 mm / min, the tensile strength after brazing (proof stress: MPa) It was measured.
Based on the tensile test results, the strength evaluation was determined according to the following criteria (represented by ◎ ΔΔ ×).
(1) A: Tensile strength exceeded 55 MPa.
(2) ○: The tensile strength was in the range of more than 50 MPa and less than 55 MPa.
(3) Δ: Tensile strength was in the range of more than 45 MPa and less than 50 MPa.
(4) x: The tensile strength was less than 45 MPa.

[Self-corrosion resistance test]
Using the fin material according to the present invention obtained in the above production process and the conventional fin material, a strip-shaped sample having a size of 25 mm × 120 mm was produced, and an SST (salt spray test) was performed. Suga Test Instruments Co., Ltd .: ISO-3-CY * R was used as a salt sprayer, and the test was performed for 48 hours under the test conditions based on JIS Z 2371.
Corrosion weight loss was measured after the above test, and the self-corrosion resistance evaluation was judged according to the following criteria (represented by ◎ ○ △ ×).
(1) A: Corrosion weight loss was less than 25 mg / dm ² .
(2) ○: Corrosion weight loss was in the range of 25 mg / dm ² or more and less than 50 mg / dm ² .
(3) Δ: Corrosion weight loss was in a range of 50 mg / dm ² or more and less than 100 mg / dm ² .
(4) x: Corrosion weight loss was 100 mg / dm ² or more.

[Brassability (brazing erosion resistance) test]
Samples obtained by corrugating the fin material according to the present invention obtained in the above production process and the conventional fin material were each produced, and a tube material having a thickness of 0.3 mm (brazing sheet: core material 3003 / brazing material 4045 (10 % Brazing)) was applied to the brazing material surface, and flux was applied, followed by brazing in a high purity nitrogen gas atmosphere. The brazing treatment was performed by holding at a temperature of 600 ° C. for 3 minutes.
After the brazing treatment, a cross section of the core (fin material / tube) was observed using an optical microscope to evaluate brazing properties. The evaluation was made according to the following criteria based on the confirmation result of the wax erosion to the grain boundary of the fin material.
(1) A: The wax erosion depth to the fin material grain boundary was less than 10 μm.
(2) O: Depth of wax erosion to fin material grain boundaries was 10 μm or more and less than 20 μm.
(3) Δ: The depth of wax erosion to the fin material grain boundary was 20 μm or more and less than 30 μm.
(4) x: The depth of wax erosion to the fin material grain boundary was 30 μm or more.

[Measurement of dispersion state of low melting point intermetallic compound]
The SEM observation of the crystal grain boundary was performed using a scanning electron microscope: JSM-6360LA manufactured by JEOL Ltd., using the fin material of each component composition obtained in the above production process and the conventional fin material as samples. For a plurality of crystal grains in one sample, the number of low-melting-point compounds on a crystal grain boundary having a total length of 10 mm was measured by particle analysis.
The compound to be measured was a low melting point compound (Mg—Si or Si compound) having a particle size (equivalent circle diameter) of 0.1 to 3 μm.

  Table 1 shows a list of results in each evaluation test.

[Example 1]
By weight%: Si: 0.7, Mn: 1.7%, Ni: 0.5%, Mg: 0.015%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% A fin material according to the present invention was produced, which contains the balance Al and inevitable impurities.
As a result of the strength test, the yield strength was 62 MPa, and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 28 mg / dm ² and the evaluation was good.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 4 μm and the evaluation was ◎.
The number of low melting point compounds on the grain boundaries was 2 × 10 ² .

[Example 2]
In weight%: Si: 0.7, Mn: 1.7%, Ni: 0.5%, Mg: 0.025%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% A fin material according to the present invention was produced, which contains the balance Al and inevitable impurities.
As a result of the strength test, the yield strength was 62 MPa, and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 29 mg / dm ² and the evaluation was good.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 5 μm and the evaluation was ◎.
The number of low melting point compounds on the grain boundaries was 2 × 10 ² .

[Example 3]
By weight%: Si: 0.7, Mn: 1.7%, Ni: 0.3%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% A fin material according to the present invention was produced, which contains the balance Al and inevitable impurities.
As a result of the strength test, the yield strength was 59 MPa and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 20 mg / dm ² and the evaluation was ◎.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 3 μm and the evaluation was ◎.
The number of low melting point compounds on the grain boundaries was 2 × 10 ² .

[Example 4]
Si: 0.7, Mn: 1.7%, Ni: 0.8%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% by weight% A fin material according to the present invention was produced, which contains the balance Al and inevitable impurities.
As a result of the strength test, the yield strength was 65 MPa, and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 40 mg / dm ² and the evaluation was good.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 13 μm, and the evaluation was good.
The number of low melting point compounds on the grain boundaries was 3 × 10 ² .

[Example 5]
Si: 0.7, Mn: 1.6%, Ni: 0.5%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% by weight A fin material according to the present invention was produced, which contains the balance Al and inevitable impurities.
As a result of the strength test, the yield strength was 59 MPa and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 25 mg / dm ² and the evaluation was good.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 12 μm and the evaluation was good.
The number of low melting point compounds on the grain boundaries was 3 × 10 ² .

[Example 6]
Si: 0.7, Mn: 2.4%, Ni: 0.5%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% by weight% A fin material according to the present invention was produced, which contains the balance Al and inevitable impurities.
As a result of the strength test, the yield strength was 63 MPa, and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 38 mg / dm ² and the evaluation was ◎.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 3 μm and the evaluation was ◎.
The number of low melting point compounds on the grain boundaries was 1 × 10 ² .

[Comparative Example 1]
In weight%: Si: 0.7, Mn: 1.7%, Ni: 0.5%, Mg: 0.007%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% A conventional fin material containing the balance Al and inevitable impurities was prepared.
As a result of the strength test, the yield strength was 62 MPa, and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 27 mg / dm ² and the evaluation was good.
As a result of the brazing (brazing erosion resistance) test, the brazing depth of the brazing was 28 μm and the evaluation was Δ.
The number of low melting point compounds on the grain boundaries was 4 × 10 ⁵ .

[Comparative Example 2]
By weight%: Si: 0.7, Mn: 1.7%, Ni: 0.5%, Mg: 0.032%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% A conventional fin material containing the balance Al and inevitable impurities was prepared.
As a result of the strength test, the yield strength was 62 MPa, and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 29 mg / dm ² and the evaluation was good.
As a result of the brazing (brazing erosion resistance) test, the brazing depth of the brazing was 22 μm and the evaluation was Δ.
The number of low melting point compounds on the grain boundaries was 6 × 10 ⁴ .

[Comparative Example 3]
By weight%: Si: 0.7, Mn: 1.7%, Ni: 0.05%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% A conventional fin material containing the balance Al and inevitable impurities was prepared.
As a result of the strength test, the yield strength was 47 MPa, and the evaluation was Δ.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 15 mg / dm ² and the evaluation was ◎.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 5 μm and the evaluation was ◎.
The number of low melting point compounds on the grain boundaries was 1 × 10 ² .

[Comparative Example 4]
By weight%: Si: 0.7, Mn: 1.7%, Ni: 1.2%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% A conventional fin material containing the balance Al and inevitable impurities was prepared.
As a result of the strength test, the yield strength was 68 MPa, and the evaluation was ◎.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 85 mg / dm ² and the evaluation was Δ.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 24 μm and the evaluation was Δ.
The number of low melting point compounds on the grain boundaries was 5 × 10 ⁵ .

[Comparative Example 5]
Si: 0.7, Mn: 1.2%, Ni: 0.5%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% by weight% A conventional fin material containing the balance Al and inevitable impurities was prepared.
As a result of the strength test, the yield strength was 49 MPa, and the evaluation was Δ.
As a result of the self-corrosion resistance test, the weight loss by corrosion was 22 mg / dm ² and the evaluation was good.
As a result of the brazing (brazing erosion resistance) test, the erosion depth of the brazing was 22 μm, and the evaluation was good.
The number of low melting point compounds on the grain boundaries was 2 × 10 ⁵ .

[Comparative Example 6]
Si: 0.7, Mn: 2.7%, Ni: 0.5%, Mg: 0.02%, Fe: 0.01%, Zn: 1.5%, Zr: 0.1% by weight% A conventional fin material containing the balance Al and inevitable impurities was prepared. However, when the test sample was manufactured, cracks occurred on the surface due to processing difficulties, and an evaluation test using the test sample could not be performed.

  Based on the above results, the aluminum alloy fin material for heat exchangers was, by weight, Si: more than 0.6% and less than 1.2%, Mn: more than 1.5% and less than 2.5%, Ni: more than 0.15% 1 %: Mg: 0.01% or more and less than 0.03%, Fe: 0.5% or less, Zn: more than 1% and 5% or less, and by making the component composition consisting of the balance Al and inevitable impurities It was revealed that a fin material having excellent strength characteristics, brazing properties, and self-corrosion resistance can be obtained.

It is a figure which shows an example of the aluminum alloy fin material for heat exchangers of this invention, and is a perspective view explaining the example which assembled | attached the aluminum alloy fin material for heat exchangers to the heat exchanger for motor vehicles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Aluminum alloy fin material (fin material) for heat exchangers, 2 ... Tube, 3 ... Header, 4 ... Side support, 10 ... Radiator (heat exchanger)

Claims (4)

By weight, Si: more than 0.6% and less than 1.2%, Mn: more than 1.5% and 2.5% or less, Ni: more than 0.15% and 1% or less, Mg: 0.01% or more and 0.03 %: Fe: 0.5% or less, Zn: more than 1% and 5% or less,
An aluminum alloy fin material for heat exchangers, characterized by comprising balance Al and inevitable impurities.   The aluminum alloy fin material for heat exchanger is further Zr: 0.05% to 0.3%, Cr: 0.05% to 0.3%, Ti: 0.05% to 0.3%, The aluminum alloy fin material for a heat exchanger according to claim 1, wherein at least one of V: 0.05% to 0.3% is contained.   An aluminum alloy fin material for heat exchangers, characterized in that the aluminum alloy fin material for heat exchanger according to claim 1 or 2 is used as a core material, and an Al-Si alloy brazing material is clad on both surfaces of the core material. . The heat exchanger provided with the aluminum alloy fin material for heat exchangers in any one of Claims 1-3.

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