JPH08302439A - Brazing sheet for heat exchanger, excellent corrosion resistance and brazability - Google Patents

Abstract

PURPOSE: To provide a brazing sheet for heat exchanger, excellent in brazability and corrosion resistance. CONSTITUTION: One side of an Al-Mn type Al alloy core material is clad with an Al-Si type Al alloy brazing filler metal. Further, the other side of the core material is clad with a sacrificial anode cladding material of Al alloy having a composition consisting of, by weight, 0.5-3% Mg, 0.0005-0.1% Be, 0.05-1.5% Mn, and the balance Al with inevitable impurities or a sacrificial anode cladding material of Al alloy having a composition consisting of 0.5-3% Mg, 0.0005-0.1% Be, 0.05-1.5% Mn, further one or >=2 kinds among 1-12% Zn, 0.005-0.1% In, and 0.01-0.3% Sn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing sheet having excellent corrosion resistance and brazing property, which is used as various structural members such as heat exchangers, and more particularly to a brazing sheet for automobile heat exchangers.

[0002]

2. Description of the Related Art Conventionally, as a brazing sheet for a heat exchanger, JIS 3003 (% by weight, Mn: 1.0 to
1.5%, Cu: 0.05 to 0.20%, Si: 0.6
% Or less, Zr: 0.7 or less%, Zn: 0.10 or less%,
Remainder: Al and unavoidable impurities) An Al-Mn-based alloy core material is clad with an Al-Si-based Al alloy brazing material on one side, and the other side of the core material contains Mg: 0.3 to 2.5%. Al alloy sacrificial anode skin material, Mg: 0.3 to 2.5%, Z
n: Al alloy sacrificial anode skin material containing 2% or less or M
g: 0.3 to 2.5%, Mn: 0.2 to 1.5%, Cu: 0.5% or less, Cr: 0.3% or less,
A brazing sheet for a heat exchanger, which is formed by clad with an Al alloy sacrificial anode skin material containing Zr: 0.2% or less, is known (see, for example, Japanese Patent Application Laid-Open No. 2-175093).

[0003]

However, the above-mentioned JIS
Si on one surface of Al-Mn-based Al alloy core material such as 3003
Al-Si-based Al alloy brazing material containing Al is clad and Al containing Mg: 0.3 to 2.5% on the other surface of the core material.
A conventional brazing sheet for a heat exchanger, which is formed by clad with an alloy sacrificial anode skin material, has the following features:
A strong oxide film is likely to be formed on the Al alloy sacrificial anode skin material containing Al, and as a result, the sacrificial anode effect is less likely to act, and only a relatively weak portion of the oxide film is selectively corroded. , Through holes are likely to occur, (b) Mg
Has the property of reacting with the flux to inactivate it and reduce the brazeability, so of course when directly brazing the sacrificial anode skin surface like a header plate of a radiator. When the plate thickness is thin even in the brazing on the surface opposite to the sacrificial anode skin material, Mg passes through the core material by diffusion to reach the brazing material surface and hinders brazing, which causes an obstacle to thinning. There was such a problem.

[0004]

From this viewpoint, the present inventors have conducted researches to obtain a brazing sheet for a heat exchanger, which is more excellent in corrosion resistance and brazing property than conventional ones. As a result, (a) Be Has an effect of suppressing the formation of an oxide film of the Al-Mg alloy, and when Be is added to the sacrificial anode skin material of the Al-Mg alloy, the sacrificial anode effect of the sacrificial anode skin material is further improved and the corrosion is uniformly performed. Pitting is unlikely to occur, and Be has an action of suppressing the reaction between Mg and the flux, and does not hinder the brazing property because it does not reduce the action of the flux. Furthermore, Mn is added to Mg and Be.
Addition to the sacrificial anode skin material further suppresses oxide film growth during brazing of the sacrificial anode skin material, and therefore M
The sacrificial anode skin material in which Mn is added at the same time as g and Be further improves the brazing property and the sacrificial anode effect.
The contents of Mg, Be and Mn added to the sacrificial anode skin material are Mg: 0.5 to 3% and Be: 0.0005 to 0.
1%, Mn: 0.05 to 1.5%, and if necessary, Zn: 1 to 12%, In: 0.005
˜0.1%, Sn: 0.01 to 0.3%, one or more kinds are preferably contained, and the remainder preferably has a composition consisting of Al and unavoidable impurities. I got it.

The present invention has been made on the basis of the above findings, and is (1) Al-Mn-based Al in% by weight.
An Al-Si type Al alloy brazing material is clad on one surface of the alloy core material, and Mg: 0.
5-3%, Be: 0.0005-0.1%, Mn:
A brazing sheet for a heat exchanger excellent in corrosion resistance and brazing property, which is obtained by clad with an Al alloy sacrificial anode skin material having a composition of 0.05 to 1.5% and the balance of Al and unavoidable impurities. ) An Al—Mn-based Al alloy brazing material is clad on one surface of the Al—Mn-based Al alloy core material, and the other one surface of the core material is Mg: 0.5 by weight%.
~ 3%, Be: 0.0005-0.1%, Mn: 0.0
5 to 1.5%, and Zn: 1 to 12%, I
n: 0.005-0.1%, Sn: 0.01-0.3%
A brazing sheet for a heat exchanger, which is excellent in corrosion resistance and brazing property, and which is obtained by clad with an Al alloy sacrificial anode skin material having a composition containing one or more of the above and the balance consisting of Al and inevitable impurities , Are characterized.

The Al-Mn-based Al alloy core material used in the brazing sheet of the present invention is not particularly limited, but in weight%, (i) Mn: 0.8 to 1.3%, S
i: 0.3 to 1.0%, Cu: 0.05 to 0.7%, Z
r: 0.05 to 0.2%, Ti: 0.05 to 0.2%, the balance being an Al alloy core material composed of Al and inevitable impurities, (ii) Mn: 0.8 to 1 .3%, Si:
0.3-1.0%, Cu: 0.05-0.7%, Zr:
0.05-0.2%, Ti: 0.05-0.2%, M
It is preferable that the Al alloy core material has a composition containing g: 0.05 to 0.3% and the balance of Al and unavoidable impurities.

Therefore, in the brazing sheet for a heat exchanger of the present invention, in the brazing sheet according to (1) or (2), the core material may be the Al alloy core material of (i) to (ii). It has characteristics. Among them, in the brazing sheet of (1) above,
It is more preferable to use the Al alloy core material of (ii), and in the brazing sheet of (2) above,
It is more preferable to use the Al alloy core material of (i).

The brazing sheet of the present invention having excellent corrosion resistance and brazing property is particularly preferably used as a structural member of a heat exchanger, and particularly preferably used as a brazing sheet for a heat exchanger of an automobile. Next, the reason why the component composition of the brazing sheet for a heat exchanger having excellent brazing property and corrosion resistance of the present invention is limited as described above will be described.

(A) Sacrificial anode skin material Mg: Mg of the sacrificial anode skin material is a component that improves the pitting corrosion resistance and the strength of the sacrificial anode skin material.
If the content is less than 0.5%, the desired effect cannot be obtained,
On the other hand, if it exceeds 3%, the brazing property is deteriorated, which is not preferable. Therefore, the content of Mg in the sacrificial anode skin material is set to 0.5 to 3%. The more preferable range of the content of Mg is 1.0 to 2.0%.

Be: Be has the effect of suppressing the oxide film growth during brazing in the sacrificial anode skin material and improving the pitting corrosion resistance, and further suppressing the reaction between Mg and the flux to act as the flux. Although it does not decrease, if the content is less than 0.0005%, the desired effect cannot be obtained, while if it exceeds 0.1%, no further effect can be obtained, which is rather costly. It is not preferable because it is too much.
Therefore, Be: 0.0005 to 0.1% is set.
A more preferable range of the content of Be is 0.001 to 0.0.
It is 05%.

When Mn: Mn is contained together with Be, Mn has an effect of more effectively suppressing the growth of the oxide film during brazing in the sacrificial anode skin material and improving the pitting corrosion resistance. If it is less than 0.05%, the desired effect cannot be obtained. On the other hand, if it exceeds 1.5%, no further effect can be obtained, and the cost is rather high, which is not preferable. Therefore, Mn is set to 0.05 to 1.5%. A more preferable range of the Mn content is 0.05-0.
3%.

Zn, In, Sn: All of these components in the sacrificial anode skin material are components that make the potential of the sacrificial anode skin material base and improve the sacrificial anode effect. Therefore, they are added as necessary. The content of each is Zn: less than 1%, I
If n: less than 0.005% and Sn: less than 0.01%, the desired effect cannot be obtained, while Zn: more than 12% and In:
If the content exceeds 0.1% and the content of Sn exceeds 0.3%, no further effect is obtained and the cost increases. Therefore,
The contents of Zn, In, and Sn in the sacrificial anode skin material are Zn: 1 to 12%, In: 0.005 to 0.1%, and S, respectively.
n: It was set to 0.01 to 0.3%. A more preferable range of these components is Zn: 1-3%, In: 0.02-0.
05%, Sn: 0.05 to 0.15%.

Inevitable impurities: Fe and Si are the main inevitable impurities contained in the sacrificial anode skin material of the brazing sheet for a heat exchanger having excellent brazing and corrosion resistance of the present invention, but from the viewpoint of corrosion resistance, It is desirable that their contents are specified to Fe: 0.7% or less and Si: 0.3% or less.

Thickness of sacrificial anode skin material: The thickness of the sacrificial anode skin material is not particularly specified, but a desirable range is
It is 5 to 30% of the plate thickness of the brazing sheet, and more preferably 10 to 20%.

(B) Core material A used in the brazing sheet for heat exchanger of the present invention
The 1-Mn-based Al alloy core material is not particularly limited, but a more preferable Al-Mn-based Al alloy core material used in the brazing sheet for a heat exchanger of the present invention is% by weight.
And Mn: 0.8 to 1.3%, Si: 0.3 to 1.0
%, Cu: 0.05 to 0.7%, Zr: 0.05 to 0.
2%, Ti: 0.05 to 0.2%, balance Al
And an Al alloy core material composed of unavoidable impurities, M
n: 0.8 to 1.3%, Si: 0.3 to 1.0%, C
u: 0.05 to 0.7%, Zr: 0.05 to 0.2%,
Ti: 0.05-0.2%, Mg: 0.05-0.3%
And an Al alloy core material having a composition containing Al and unavoidable impurities.

The component composition of the Al-Mn-based Al alloy core material is limited as described above, because Si forms Mg and Mg ₂ Si compounds diffused from the sacrificial anode skin material, and the strength after brazing is increased. Has the effect of improving, but Si: 0.3%
If the amount is less than 1, the desired effect cannot be obtained, while Si: 1.0%
If it is contained in excess of 1.0, the brazing property will be deteriorated, which is not preferable. Cu acts as a solid solution to improve the strength after brazing and to make the potential of the core material noble to improve the corrosion resistance. Has a content of 0.05
If it is less than 0.7%, the desired effect cannot be obtained. On the other hand, if it exceeds 0.7%, the intergranular corrosion susceptibility increases and the corrosion resistance decreases, which is unfavorable. Furthermore, Zr, Ti, Mn crystallizes or precipitates as an intermetallic compound and has the effect of improving the strength after brazing, but Zr: less than 0.05%, Ti: less than 0.05%, M
If n is less than 0.8%, the desired effect cannot be obtained, while
Zr: more than 0.2%, Ti: more than 0.2%, Mn:
If it exceeds 1.3%, no further effect can be obtained, leading to an increase in cost, which is not preferable. Further, Mg is added as necessary to obtain Mg ₂ S.
It has an action of further forming the i compound and further improving the strength after brazing, but if Mg: less than 0.05%, the desired effect cannot be obtained, while if it exceeds Mg: 0.3%, it contains. This is because the brazing property is lowered, which is not preferable.

(C) Brazing material A used in the brazing sheet for heat exchanger of the present invention
The 1-Si-based Al alloy brazing material is not particularly limited as long as it is a normal Al-Si-based Al alloy brazing material, but Si contained in the brazing material lowers the melting point of the brazing material and causes fluidity. If the content is less than 5%, the desired effect cannot be obtained, while if it exceeds 15%, the fluidity is rather deteriorated, which is not preferable.
Therefore, the content of Si in the brazing material is set to 5 to 15%. A more preferable range of Si content in the brazing material is 7
~ 11%.

[0018]

EXAMPLE An Al alloy having the composition shown in Tables 1 and 2 was melted and cast to produce an ingot. The ingot was homogenized under normal conditions and hot-rolled to a thickness of 30.
mm hot rolled sheets were used to produce sacrificial anode skin materials A to U.

[0019]

[Table 1]

[0020]

[Table 2] (* Indicates a value outside the scope of the present invention)

Next, Al alloys having the compositional compositions shown in Tables 3 to 4 are melted and cast to produce an ingot. The ingot is homogenized under normal conditions and then hot rolled to obtain a thickness. : 150 mm hot-rolled plate, and core materials a to p were produced.

[0022]

[Table 3]

[0023]

[Table 4]

Further, an Al alloy having the composition shown in Table 5 was melted and cast to produce an ingot, which was homogenized under normal conditions and then hot-rolled to a thickness of:
A 20 mm hot rolled plate was used to prepare brazing filler metals a to o.

[0025]

[Table 5]

Sacrificial anode skin materials A to U having the component compositions shown in Tables 1 and 2, core materials a to p having the component compositions shown in Tables 3 to 4, and brazing filler metals a to o having the component compositions shown in Table 5. Are superposed in the combinations shown in Tables 6 to 7, clad by hot rolling, and then cold rolled while appropriately performing intermediate annealing to obtain a sheet thickness: 0.20 mm, temper H14 (final cold rolling rate. : 3
0%) brazing sheet for heat exchanger of the present invention (hereinafter,
Inventive brazing sheets) 1 to 16, comparative heat exchanger brazing sheets (hereinafter referred to as comparative brazing sheets) 1 to 4 and conventional heat exchanger brazing sheets (hereinafter referred to as conventional brazing sheets) 1 were produced.

These brazing sheets 1 to 1 of the present invention
6. Comparative brazing sheets 1 to 4 and conventional brazing sheet 1 were subjected to the following corrosion test, brazing test and tensile test to evaluate corrosion resistance, brazing property and strength after brazing.

Corrosion Test Assuming that the brazing sheet is brazed,
After subjecting the test pieces of the present brazing sheets 1 to 16, the comparative brazing sheets 1 to 4 and the conventional brazing sheet 1 to heat treatment at 600 ° C. for 5 minutes in a nitrogen atmosphere, the test pieces were added to 10 ° C. 10 ppm Cu 2 ⁺ -added tap water at 60 ° C. Soak,
The number of days until a through hole was formed was measured, and the results are shown in Tables 6 and 7, and the corrosion resistance of the brazing sheet after brazing was evaluated.

Brazing test 1 A with corrugated width: 20 mm, plate thickness: 80 μm
1-1.2% Mn-1.0% Si-1.5% Zn Al
Alloy fin material, brazing sheets 1 to 16 of the present invention having the same width as the fin material, comparative brazing sheets 1 to 1
4 and the conventional brazing sheet 1, Al alloy fin material is brought into contact with the brazing material surface of the brazing sheet at 15 positions as shown in FIG. After brazing by the Nocolock brazing method under the conditions of 600 ° C. for 5 minutes, the Al alloy fin material was peeled off. The surface of the brazing sheet obtained by peeling off the Al alloy fin material is shown in FIG. Let ΣL be the total length of the brazing wire left on the surface of the brazing sheet from which the Al alloy fin material has been stripped off, and ΣL ₀ be the total length of the brazing wire when ideal brazing is performed, ΣL / ΣL ₀ × 100
(%) Was defined as the bonding rate, the bonding rate was measured, and the results are shown in Tables 6 and 7 to evaluate the brazing property. The brazing rate has a great influence on the heat exchange efficiency and durability, and if it exceeds 90%, it is not practical.

Brazing Test 2 The brazing sheets 1 to 16 of the present invention, the comparative brazing sheets 1 to 4 and the conventional brazing sheet 1 are shown in FIG.
As shown in FIG. 2 (b), as shown in FIG. 2 (b), after being combined in an inverted T shape and brought into contact with each other, and a fluoride-based flux was applied, it was kept in a nitrogen atmosphere at 600 ° C. for 5 minutes. After brazing, the throat thickness of the brazing part on the sacrificial anode skin material side was measured, and the results are shown in Tables 6 and 7 to evaluate the brazing property.

Tensile Test The brazing sheets 1 to 16 of the present invention, the comparative brazing sheets 1 to 4 and the conventional brazing sheet 1 were heat-treated at 600 ° C. for 5 minutes in a nitrogen atmosphere, and then subjected to a tensile test. Shown in Table 6 and Table 7, the strength of the brazing sheet after brazing was evaluated.

[0032]

[Table 6]

[0033]

[Table 7]

[0034]

From the results shown in Tables 6 and 7, it is understood that the brazing sheets 1 to 16 of the present invention are superior in corrosion resistance and brazing property to the conventional brazing sheet 1. However, comparative brazing sheets 1-
It can also be seen that No. 4 is inferior in any of corrosion resistance, brazing property and strength after brazing. As described above, the brazing sheet for a heat exchanger of the present invention is excellent in both corrosion resistance and brazing property, and can greatly contribute to the development of industry.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a method of evaluating a brazing property by a brazing test.

FIG. 2 is an explanatory diagram showing a method of evaluating brazing property by a brazing test.

Claims (4)

[Claims] 1. An Al-Mn-based Al alloy core material with Al on one side.
-Si-based Al alloy brazing material is clad, and on the other side of the core material, in weight%, Mg: 0.5-3%, Be: 0.0005-0.1%, Mn: 0.05-. A brazing sheet for a heat exchanger excellent in corrosion resistance and brazing property, which is obtained by clad with an Al alloy sacrificial anode skin material having a composition of 1.5% and the balance being Al and unavoidable impurities. 2. An Al-Mn-based Al alloy core material is coated with Al on one surface.
-Si-based Al alloy brazing material is clad, and on the other side of the core material, in weight%, Mg: 0.5-3%, Be: 0.0005-0.1%, Mn: 0.05-. 1.5%, and further, one or more of Zn: 1 to 12%, In: 0.005 to 0.1%, Sn: 0.01 to 0.3%, A brazing sheet for a heat exchanger having excellent corrosion resistance and brazing property, which is obtained by clad with an Al alloy sacrificial anode skin material containing Al and unavoidable impurities with the remainder being Al. 3. The Al-Mn-based Al alloy core material, in% by weight, Mn: 0.8-1.3%, Si: 0.3-1.0%, Cu: 0.05-0. 7%, Zr: 0.05 to 0.2%, Ti: 0.05 to 0.2%, and the balance being an Al alloy core material having a composition of Al and inevitable impurities. A brazing sheet for a heat exchanger, which is excellent in corrosion resistance and brazing property according to claim 1. 4. The weight percentage of the Al—Mn-based Al alloy core material is Mn: 0.8 to 1.3%, Si: 0.3 to 1.0%, Cu: 0.05 to 0. 7%, Zr: 0.05 to 0.2%, Ti: 0.05 to 0.2%, Mg: 0.05 to 0.3%, with the balance being Al and inevitable impurities. A brazing sheet for a heat exchanger having excellent corrosion resistance and brazing properties according to claim 1 or 2, which is an Al alloy core material.