JPH1112671A - High strength aluminum alloy brazing sheet excellent in brazability and corrosion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high strength aluminum alloy brazing sheet excellent in corrosion resistance as well as in brazability at brazing performed at the time of producing a heat exchanger. SOLUTION: This aluminum alloy brazing sheet is produced by cladding a core material, having a composition consisting of, by weight, 1.0-1.8% Mn, 0.30-0.60% Cu, 0.30-1.0% Si, 0.02-0.09% Mg, 0.05-0.15% Zr, <=0.50% Fe, and the balance Al with the inevitable impurities, with an Al-Si alloy brazing filler metal. Further, either or both of 0.05-0.25 wt.% Ti and 0.05-0.15 wt.% V can be incorporated into the above core material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength aluminum alloy brazing sheet excellent in brazing properties and corrosion resistance suitable for use as a tube (tube) of a heat exchanger of an automobile or the like.

[0002]

2. Description of the Related Art Conventionally, in a heat exchanger, a large number of tubes are connected to a pipe called a header pipe, and the internal space of each tube communicates with the internal space of the header pipe.
2. Description of the Related Art There is known a heat exchanger having a structure in which a fin member is arranged between a plurality of tubes to enhance heat exchange property. In the heat exchanger having this configuration, the medium is circulated between the inside of the header pipe and the inside of each tube, so that heat can be efficiently exchanged through the fins arranged between the tubes.
Also, conventionally, the core material is composed of an Al-Mn-based alloy,
Using a brazing sheet clad with an Al-Si alloy brazing material on the core material, forming a tube with the brazing sheet, forming a fin material with an Al alloy bare material,
Heat exchangers manufactured by brazing these tubes and fin materials using a fluoride-based flux are known, and such heat exchangers have become the mainstream in automotive heat exchangers. I have.

[0003]

On the other hand, Mg is added to the Al alloy.
Is known to improve the mechanical strength,
It is conceivable that the mechanical strength of the heat exchanger can be improved by forming the brazing sheet using an Al alloy containing Mg, but if an Al alloy containing Mg is used as the core material of the brazing sheet, And the flux react during brazing, and the brazing property is remarkably reduced, so that the core material made of an Al alloy containing Mg has been rarely used conventionally.

However, improving the mechanical strength of the heat exchanger and improving the corrosion resistance are always required in this field. There is a demand for the development of an aluminum alloy brazing sheet that is strong and has excellent corrosion resistance.

The present invention has been made in view of the above circumstances, and has an excellent brazing property, a high corrosion resistance, and a high strength aluminum alloy at the time of brazing performed when manufacturing a heat exchanger. It is intended to provide a brazing sheet.

[0006]

According to the present invention, in order to solve the above-mentioned problems, Mn is 1.0 to 1.8 wt% and Cu is 0.30.
~ 0.60 wt%, Si: 0.30 ~ 1.0 wt%, Mg: 0.3.
Al-Si-based or A-containing core material containing 0.05 to 0.15 wt% of Zr and 0.55 wt% or less of Fe, and the balance of Al and unavoidable impurities.
It is formed by cladding an l-Si-Zn alloy brazing material.

In order to solve the above-mentioned problems, the present invention provides Mn: 1.0 to 1.8 wt% and Cu: 0.30 to 0.60.
wt%, Si: 0.30 to 1.0 wt%, Mg: 0.02 to 0.0
09 wt%, Zr: 0.05-0.15 wt%, and Fe is set to 0.50 wt% or less, and Ti: 0.05-0.5 wt%.
0.25 wt%, V: 0.05 to 0.15 wt%, one or two
The core material containing seeds and the balance of Al and unavoidable impurities
It is formed by cladding an Al-Si-based or Al-Si-Zn-based brazing alloy.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. The brazing sheet according to the first embodiment of the present invention has a Mn of 1.0 to 1.8 wt%, a C
u: 0.30 to 0.60 wt%, Si: 0.30 to 1.0 wt%
%, Mg: 0.02 to 0.09 wt%, Zr: 0.05 to 0.05%
0.15 wt%, Fe is 0.50 wt% or less, and the core material composed of the balance of Al and unavoidable impurities contains Al-S
It is formed by cladding an i-based or Al-Si-Zn-based alloy brazing material.

Next, a brazing sheet according to a second embodiment of the present invention has a Mn of 1.0 to 1.8 wt% and a Cu of 0.1 wt%.
30 to 0.60 wt%, Si: 0.30 to 1.0 wt%, M
g: 0.02 to 0.09 wt%, Zr: 0.05 to 0.15 wt%
%, Fe is 0.50 wt% or less, Ti: 0.05 to 0.25 wt%, and V: 0.05 to 0.1 wt%.
Al-Si-based or Al-Si-Z containing 5 wt% of one or two kinds, with the balance consisting of Al and unavoidable impurities
It is made by cladding an n-type brazing alloy. In this specification, the composition range of the additive element is, for example, 1.
When expressed as 0 to 1.8%, the lower and upper critical values are included, so 1.0 to 1.8% means 1.0% or more and 1.8% or less. Shall be.

The reasons for limiting each of the additional elements will be described below. Mg: Although the strength of an Al alloy is improved by adding Mg to Al, if the content is less than 0.02% by weight, the effect of improving the strength is almost negligible, and the content is reduced to 0.2%.
If the content exceeds 09% by weight, the brazing property of the brazing sheet is undesirably deteriorated. Therefore, the amount of Mg added is set to 0.1.
It is necessary to be in the range of 02 to 0.09 wt%. Mn,
Si: Mn and Si are elements added mainly for improving the strength. When Mn is less than 1.0 wt% and Si is less than 0.3 wt%, the strength improving effect is insufficient.
Exceeds 1.8 wt%, the workability deteriorates, and the Si content becomes 1.0 wt%.
%, It is not preferable because the melting point of the material lowers and melting occurs due to heating during brazing. Therefore, it is preferable that the addition amount of Mn be in the range of 1.0 to 1.8 wt% and the Si content be in the range of 0.30 to 0.60 wt%.

Cu: Cu improves the strength of Al alloy and increases
Added to lower the potential of the alloy core material, but 0.3 wt%
If less than 0.6 wt., These effects are not sufficient.
%, The corrosion rate of the Al alloy core material is undesirably increased. Therefore, it is preferable that the addition amount of Cu be in the range of 0.3 to 0.6 wt%.

Zr: Zr is added in order to flatten the crystal grain structure of the core material at the time of brazing and to suppress the erosion of the braze core material. If the Zr content is less than 0.05 wt%, the effect of preventing erosion is insufficient, and if the Zr content exceeds 0.15 wt%, A
It is not preferable because the workability of the material as an alloy deteriorates. Therefore, it is preferable that the addition amount of Zr be in the range of 0.05 to 0.15 wt%.

Ti, V: Ti and V are added to promote the effect of adding Zr, and Ti and V are added in order to effectively exert the effect of preventing erosion and the effect of preventing the deterioration of workability by adding Zr. 0.05 to 0.25 wt%, V: 0.05 to 0.2%
It is preferable to add in the range of 15 wt%. Fe: Fe is an element that is not preferable as an element contained in the Al alloy for the brazing sheet, so that it is preferable to keep it as low as possible, and it is preferable that the content be 0.5 wt% or less.

FIG. 1 shows an example of a heat exchanger constituted by using the brazing sheet according to the present invention. In this example, a heat exchanger A is a header which is arranged at right and left sides and extends vertically. Pipes 1 and 2 and these header pipes 1 and 2 are parallel to each other with a gap between each other,
Further, it is mainly composed of a plurality of tubes 3 joined at right angles to the header pipes 1 and 2 and a plurality of corrugated fin members 4 brazed to the tubes 3. The header pipes 1 and 2, the tube 3, and the fin member 4 are each made of Al or an Al alloy having excellent thermal conductivity. Among them, for example, the tube 3 is a core material of the Al alloy having the above composition. And a brazing sheet made of an Al-Si or Al-Si-Zn alloy brazing material layer provided on the surface thereof, and the fin member 4 is made of an Al alloy bare material.

In order to braze the fin member 4 to the tube 3 when manufacturing the heat exchanger A having the above-mentioned structure, the brazing material layer on the joining surface in a state where the fin member 4 is in contact with the tube 3 made of a brazing sheet. Is melted, and then the melted portion is cooled and solidified to form the fillet portion 6a, so that brazing can be performed. At the time of this brazing, A
Tube 3 made of brazing sheet made of 1 alloy
Is used, the brazing property does not decrease even if Mg is contained, and the tube 3 itself exhibits excellent mechanical strength. Further, since the tube 3 is also excellent in corrosion resistance, it has a feature that it is hardly corroded even if it is used as a heat exchanger for a long time and placed in a corrosive environment.

[0016]

EXAMPLE A structure shown in FIG. 1 was adopted as a heat exchanger.
Using an Al alloy having the composition shown in FIG.
An Al alloy brazing material having a composition of 7.5% Si was used, and a brazing material layer was clad-pressed to a core material to obtain a brazing sheet having a thickness of 0.3 mm. AA7072 is used as a fin material.
An Al alloy having a composition of (Al-1% Zn) was used. The brazing is performed by a Nocolok brazing method in a flux-applied N ₂ gas atmosphere at 600 ° C. for 3 minutes. The brazing material layer at the contact portion between the bent portion of the fin member and the tube is melted and solidified to exchange heat. The vessel was assembled. In addition, the results of measuring the tensile strength when a brazing sheet having a core material having the composition shown in Table 1 below was brazed and heat-treated were measured with a tensile tester, and the results when the brazing sheet and the fin were combined and brazed. The result of measuring the joining rate,
Table 2 shows the results of measuring the residual ratio of core material and workability after the heat treatment for brazing.

[0017]

[Table 1]

[0018]

[Table 2]

In Table 2, the brazing property was evaluated by brazing a single brazing sheet and measuring the tensile strength. The corrosion resistance was evaluated by combining a fin and a brazing sheet and measuring the maximum pitting depth of the brazing sheet after SWAAT (ASTMG85-65).
The core material erosion degree was evaluated by a core material residual ratio after brazing heat treatment (core material thickness after brazing / core material thickness before brazing).
The workability was evaluated by the occurrence of cracks at the end of the plate during cold working (rolling). The mark ○ indicates no problem, and the mark ● indicates that the crack progresses to the center of the plate when clad-bonded to the brazing material layer. The brazing sheet cannot be produced. Note that N
In the sample of o.14, the core material was melted during brazing.

The samples of Nos. 1 to 6 shown in Table 1 correspond to the invention examples of the present invention, and all the samples have any of tensile strength, brazing property, core material remaining rate, pit depth, and workability. Excellent results were also obtained. On the other hand, in the samples of Nos. 7 and 8 in which the Mg content was outside the scope of the claims, the sample of No. 7 had low strength and the sample of No. 8 had poor brazing properties. (The joint with the fin material cannot be made.) Next, in the sample in which Zr is out of the range of the claims, the sample of No. 9 has poor core erosion (low core material remaining ratio), .10
It is clear that the workability of sample No. is low and a brazing sheet cannot be produced. Further, in the samples of Nos. 11 and 12 in which Cu was out of the scope of the claims,
It is clear that the pit depth is remarkably large and the corrosion resistance is inferior, and the tensile strength of the sample of No. 11 is also low. Further, N is used in which Si is out of the scope of the claims.
The sample No. 13 could not produce a brazing sheet when clad-pressed, and the sample No. 14 melted the core material during brazing, making it impossible to measure each characteristic.

[0021]

As described above, according to the present invention, a specific amount of Mn, Cu, Si, Mg, and Zr is contained in Al.
Content is kept low, and the effect of adding a specific amount of Mg ensures sufficient strength and brazing properties as a brazing sheet for heat exchangers, and the effect of adding a specific amount of Zr ensures workability and brazing properties. In addition, due to the effect of adding a specific amount of Cu, it has a feature excellent in corrosion resistance. In addition, by adding specific amounts of Ti and V in addition to the above composition,
It is possible to provide a brazing sheet in which the erosion of the brazing material into the brazing material during brazing can be further suppressed, and the brazing property is improved.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of a heat exchanger configured using a brazing sheet according to the present invention.

FIG. 2 is a sectional view showing a joint between a tube and a fin member in the heat exchanger shown in FIG.

[Explanation of symbols]

A: heat exchanger, 1, 2: header pipe, 3: tube, 4: fin member, 6: brazing portion, 6a: fillet portion.

Claims (2)

[Claims] 1. Mn: 1.0-1.8 wt%, Cu: 0.3
0 to 0.60 wt%, Si: 0.30 to 1.0 wt%, Mg:
0.02 to 0.09 wt%, Zr: 0.05 to 0.15 wt%, Fe is 0.50 wt% or less, and the balance is Al
A high-strength aluminum alloy brazing sheet excellent in brazing properties and corrosion resistance, wherein an Al-Si-based or Al-Si-Zn-based alloy brazing material is clad on a core material made of unavoidable impurities. 2. Mn: 1.0-1.8 wt%, Cu: 0.3
0 to 0.60 wt%, Si: 0.30 to 1.0 wt%, Mg:
0.02 to 0.09 wt%, Zr: 0.05 to 0.15 wt%,
And Fe is 0.50 wt% or less, and
Ti: 0.05 to 0.25 wt%, V: 0.05 to 0.15 wt%
% Or more, and a core material comprising the balance of Al and unavoidable impurities is clad with an Al-Si-based or Al-Si-Zn-based alloy brazing material. High strength aluminum alloy brazing sheet with excellent corrosion resistance.