JPH06306519A - Aluminum alloy fin material for vacuum brazing and its production - Google Patents

Abstract

PURPOSE:To provide an aliminum alloy fin material for vacuum brazing having an excellent sacrificial anodic effect and excellent in high temp. buckling resistance and to provide its producing method. CONSTITUTION:This fin material contains, by weight, 0.3 to 2.0% Mn, 0.5 to 3.0% Zn, 0.01 to 0.3% Ca, 0.005 to 0.1% In, 0.05 to 0.6 Cu, 0.1 to 1.2% Si, 0.1 to 1.0% Mg, 0.05 to 0.3% Cr, 0.05 to 0.3% Zr, 0.005 to 0.2% Ti and >=0.3% Fe and furthermore contains, at need, one more or >=two kinds among <=3.0% Ni, <=1.0% Vm <=0.5% Co, <=0.5% Hf and <=0.5% W, and the balance Al.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy fin material having an excellent sacrificial anode effect and excellent in high temperature buckling resistance, and a method for manufacturing the same, and particularly manufactured by a vacuum brazing method. It is used as a fin for radiators, heaters, condensers, etc. of heat exchangers for automobiles.

[0002]

2. Description of the Related Art Most heat exchangers for automobiles use Al and Al alloys and are manufactured by a brazing method. Usually, the brazing method uses an Al—Si based brazing material, and therefore brazing is performed at a high temperature of about 600 ° C. For example, a heat exchanger such as a radiator is shown in FIG.
As shown in FIG. 1, a plurality of flat tubes 1 are integrally formed with thin fins 2 processed into a corrugated shape, and both ends of the flat tubes 1 are opened in a space formed by a header 3 and a tank 4, respectively. The high-temperature refrigerant is sent from the space on the one tank side through the flat tube 1 to the space on the other tank 4 side, and the low-temperature refrigerant is circulated again by exchanging heat between the flat tube 1 and the thin fins 2. It is a thing.

By the way, in recent years, Zn has been added to fin materials,
Although the effect of a sacrificial anode fin is given to prevent corrosion of the flat tube, the vacuum brazing method is used to remove Z in the material.
There is a problem that n is evaporated, the amount of Zn remaining in the fin material is reduced, and the sacrificial anode effect becomes insufficient. In order to solve this problem, a method of preventing evaporation of Zn by adding Ca has been proposed. But the heat exchanger is small,
Since it is in the direction of weight reduction and thinning of the material is desired, when the conventional material is thinned, the evaporation prevention effect of Zn becomes small depending on the conditions of vacuum brazing, and the sacrificial anode effect is reduced. Deterioration, buckling of fins during brazing heating, and insufficient strength after heating are problems.

[0004]

In view of this, the present invention has an aluminum alloy fin material for vacuum brazing which has an excellent sacrificial anode effect and is excellent in high temperature buckling resistance regardless of vacuum brazing conditions. And a method of manufacturing the same. That is, the invention according to claim 1 has Mn of 0.3 to 2.0 wt%,
Zn 0.5-3.0 wt%, Ca 0.01-0.3 wt%, In 0.005
~ 0.1 wt%, Cu 0.05 ~ 0.6 wt%, Si 0.1 ~ 1.2 wt%
%, Mg0.1-1.0 wt%, Cr0.05-0.3 wt%, Zr0.
The aluminum alloy fin material for vacuum brazing is characterized by containing 05 to 0.3 wt%, Ti 0.005 to 0.2 wt%, Fe 0.3 wt% or less, and the balance being Al. Claim 2
The described invention is Mn 0.3 to 2.0 wt%, Zn 0.5 to 3.0 wt%
%, Ca 0.01 to 0.3 wt%, In 0.005 to 0.1 wt%, Cu
0.05 to 0.6 wt%, Si 0.1 to 1.2 wt%, Mg 0.1 to 1.0
wt%, Cr0.05-0.3 wt%, Zr0.05-0.3 wt%, Ti
0.005 to 0.2 wt%, Fe 0.3 wt% or less, and further one of Ni 3.0 wt% or less, V 1.0 wt% or less, Co 0.5 wt% or less, Hf 0.5 wt% or less, W 0.5 wt% or less, or It is an aluminum alloy fin material for vacuum brazing, characterized in that it contains two or more kinds and the balance is made of Al.
The invention according to claim 3 is such that Mn 0.3 to 2.0 wt% and Zn
0.5 to 3.0 wt%, Ca 0.01 to 0.3 wt%, In 0.005 to 0.1
wt%, Cu 0.05 to 0.6 wt%, Si 0.1 to 1.2 wt%, M
g 0.1-1.0 wt%, Cr 0.05-0.3 wt%, Zr 0.05-0.
An aluminum alloy ingot containing 3 wt%, Ti 0.005 to 0.2 wt%, Fe 0.3 wt% or less, and the balance being Al
After homogenizing at ~ 560 ℃ for 1 ~ 24 hours, hot rolling and then cold rolling, at least one intermediate annealing at 380 ~ 450 ℃ for 0.5 ~ 6 hours is performed. A method for producing an aluminum alloy fin material for vacuum brazing, which comprises performing cold rolling at a cold rolling rate of 20 to 40% after intermediate annealing. The invention according to claim 4 has an Mn of 0.3 to 2.0.
wt%, Zn 0.5-3.0 wt%, Ca 0.01-0.3 wt%, In
0.005-0.1 wt%, Cu 0.05-0.6 wt%, Si 0.1-1.
2 wt%, Mg0.1-1.0 wt%, Cr0.05-0.3 wt%, Z
r 0.05 to 0.3 wt%, Ti 0.005 to 0.2 wt%, Fe 0.3 wt
% Or less, Ni 3.0 wt% or less, V 1.0 wt%
Below, Co 0.5wt% or less, Hf 0.5wt% or less, W 0.5wt
% Or less, one or more kinds are contained, and the balance is Al
Aluminum alloy ingot consisting of 1 to 24 at 420 to 560 ℃
After homogenizing for a period of time, hot rolling is performed, and then cold rolling is performed by performing one or more intermediate annealings at a temperature of 380 to 450 ° C for 0.5 to 6 hours, and then performing a cold rolling reduction after the final intermediate annealing. A method for producing an aluminum alloy fin material for vacuum brazing, which comprises performing cold rolling at 20 to 40%.

[0005]

The reason for limiting the alloy composition as described above in the present invention is as follows. Mn has the function of improving the strength of the alloy. The content is limited to 0.3 to 2.0 wt% because if it is less than 0.3 wt%, sufficient strength cannot be obtained.
If it exceeds 2.0 wt%, Al-Mn-Fe or Al-Mn
This is because the amount of —Fe—Si-based crystallized substances increases, recrystallized grains become finer during brazing heating, and high temperature buckling resistance deteriorates.

Zn is added in order to impart a sacrificial anode effect to the fin material. The content of Zn is set to 0.5 to 3.0 wt%. If the content is less than 0.5 wt%, the effect is insufficient.
This is because if the content exceeds wt%, Zn evaporates during vacuum brazing and pollutes the furnace, which is not preferable in operation.

Ca is added in order to prevent Zn from evaporating during vacuum brazing, and its content is 0.01-.
The reason why the content is limited to 0.3 wt% is that if it is less than 0.01, the effect is not sufficient, and if it exceeds 0.3 wt%, the rolling property is deteriorated and the fin manufacturing becomes difficult.

In is added to give the fin material a sacrificial anode effect, and its content is 0.005 to 0.1 wt%.
Is less than 0.005 wt%, the effect is insufficient,
This is because if it exceeds 0.1 wt%, not only the effect is saturated, but also the conductivity is lowered.

Cu has the function of improving the strength of the alloy. The content was limited to 0.05-0.6 wt% because it was 0.05
If it is less than wt%, the effect cannot be obtained, and if it exceeds 0.6 wt%, the potential becomes noble, and the effect of making the potential base by the addition of Zn or In becomes insufficient and the sacrificial anode effect cannot be obtained. is there.

Si improves the strength of the alloy and A
1-Mn-Si-based fine precipitates are produced, the recrystallized grains are coarsened, and the high temperature buckling resistance during brazing is improved. The reason for limiting the content to 0.1-1.2 wt% is
If it is less than 0.1 wt%, the effect is small, and if it exceeds 1.2 wt%, the amount of Al-Mn-Fe-Si-based crystallized substances increases, and the recrystallized grains become fine during brazing and the high temperature buckling resistance is improved. It deteriorates.

Mg has the function of improving the strength of the alloy. The content of 0.1-1.0 wt% is 0.1 wt%
If the amount is less than the above, a sufficient effect cannot be obtained, and the upper limit is set to 1.0 wt% because Mg evaporates during vacuum brazing and pollutes the furnace, which is not preferable in operation.

Zr has the function of increasing the strength and coarsening the recrystallized grains to prevent the high-temperature buckling property from decreasing during brazing and heating. The content is limited to 0.05 to 0.3 wt% because the effect is insufficient if it is less than 0.05 wt%.
This is because if it exceeds wt%, cracking will occur during casting.

Cr has a function of improving strength. The content is limited to 0.05 to 0.3 wt% because if it is less than 0.05 wt%, a sufficient effect cannot be obtained, and if it exceeds 0.3 wt%, the plastic workability is deteriorated.

Ti has the effect of refining crystal grains during casting and preventing cracks during casting. Its content is 0.005 to 0.
The reason why the content is limited to 2 wt% is that if it is less than 0.005 wt%, a sufficient effect cannot be obtained, and if it exceeds 0.2 wt%, the plastic workability of the fin material deteriorates.

Fe has a function of improving strength. The content is specified to be 0.3 wt% or less because the content of Al-Mn-Fe or Al-Mn-Fe-Si exceeds 0.3 wt%.
This is because the amount of crystallized substances in the system increases, the recrystallized grains become fine during heating for brazing, and the high temperature buckling resistance deteriorates.

Ni, V, Co, Hf and W have the function of improving the strength without impairing the sacrificial anode effect. The upper limits of the respective contents are defined because the plastic workability of the fins is significantly reduced when the upper limits are exceeded.

Next, a method for manufacturing the aluminum alloy fin material of the present invention will be described. First, the reason why the aluminum alloy ingot is homogenized at 420 to 560 ° C for 1 to 24 hours is to precipitate Mn and Si, which are in solid solution during casting, as fine intermetallic compounds. The Al-Mn-Si-based particles that have been deposited on the surface improve the high temperature buckling resistance. However, if the homogenization temperature is lower than 420 ° C, the homogenization of segregation during casting is insufficient, and if it exceeds 560 ° C, the precipitates become coarse, and the effect of improving the high temperature buckling resistance cannot be obtained. The holding time of the homogenization treatment is set to 1 to 24 hours, because if it is less than 1 hour, fine precipitates are not sufficiently formed and the effect of improving the high temperature buckling resistance is insufficient. If it exceeds 24 hours, the precipitates become coarse during the holding, and the effect of improving the high temperature buckling resistance cannot be obtained.

The reason why the intermediate annealing temperature is 380 to 450 ° C. is that
If the temperature is lower than 380 ° C, extremely fine precipitates will be generated during annealing. Due to the pinning effect, recrystallization during brazing will be delayed and the high temperature buckling resistance will decrease. This is because the material becomes coarse and the high temperature buckling resistance is reduced. The holding time of the intermediate annealing is set to 0.5 to 6 hours because the high temperature buckling resistance is lowered even if it is less than 0.5 hours or more than 6 hours for the same reason as above.

After the final intermediate annealing, the final cold rolling rate until the desired finished plate thickness is set to 20 to 40% is to provide appropriate strength, corrugation property, and buckling during core assembly. This is to prevent it and improve the high temperature buckling resistance during brazing heating. If it is less than 20%, the recrystallization of the fin material is not completed during brazing and heating, and the high temperature buckling resistance deteriorates. If it exceeds 40%, the recrystallized grains during brazing become fine and the high temperature buckling resistance becomes insufficient.

[0020]

EXAMPLES The present invention will now be described in more detail with reference to Examples. Aluminum alloy ingots having the alloy compositions shown in Tables 1 to 3 were produced by water cooling casting, subjected to the homogenization treatment shown in Tables 4 to 6, and then hot rolled to obtain a plate having a plate thickness of 3.5 mm. This is subjected to cold rolling and intermediate annealing shown in Tables 4 to 6 to obtain the final plate thickness.
Finished to 0.06mm fin material. The high temperature buckling resistance and corrosion resistance of the fin material thus obtained were measured. The results are also shown in Tables 4-6. The high temperature buckling resistance is 22m wide from the aluminum alloy fin material for vacuum brazing
A sample of m and 60 mm in length is cut out, and the sample 6 is mounted on the table 7 using the fixture 8 as shown in FIGS. 2 (a) and 2 (b).
Hold it with a stick so that it protrudes 50 mm, and hold it in a vacuum furnace for 605
The sample was heated at a temperature of ° C for 10 minutes, and the drooping amount after heating was measured as shown in Fig. 2 (c). In this evaluation method, the amount of droop is 15
It was confirmed that there is no problem if the actual radiator is assembled and vacuum brazed if it is less than mm. As for corrosion resistance, as shown in Fig. 3, after corrugating the fin material, 0.5 mm thick JIS BAS131 brazing sheets were attached to both sides and brazed by vacuum brazing. The pitting corrosion depth generated in the brazing sheet was measured by performing 6000 hours accordingly.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

[Table 5]

[0026]

[Table 6]

As is clear from Tables 4 to 6, the invention sample N
o.1 to 28 have shallow pitting depth and small drooping amount,
It turns out that it is superior to the conventional example No.44. On the other hand, Comparative Examples No. 29 to 39 in which the alloy composition is out of the range of the present invention
It is understood that either of the pitting depth and the drooping amount is inferior to the inventive examples. Further, it can be seen that Comparative Examples Nos. 40 to 43 whose manufacturing methods are out of the scope of the present invention have a small pitting corrosion, but have a large drooping amount and are inferior to the inventive examples. Here, comparative alloys No. 33, 39, 42, 43 shown in Table 3
In both cases, the plastic workability was inferior and a fin material of 0.06 mm could not be obtained, so the high temperature buckling resistance test and the corrosion resistance test could not be performed.

[0028]

As described above, according to the present invention, evaporation of Zn during vacuum brazing is small, and an excellent sacrificial anode effect is exhibited.
In addition, the aluminum alloy fin material for vacuum brazing, which is excellent in high temperature buckling resistance, can be produced, which is a remarkable effect.

[Brief description of drawings]

FIG. 1 is a perspective view showing a radiator with a part cut away.

FIG. 2 is an explanatory diagram of a test method for high temperature buckling resistance of fin materials. (A) A side view showing a mounting state of the sample. (B) The same plan view. (C) A side view showing the hanging state of the sample.

FIG. 3 is a side view showing a test piece for a pitting corrosion test.

[Explanation of symbols]

 1. Flat tube 2. Thin fin 3. Header 4. Tank 5. Packing 6. Sample 7. Stand 8. Fixture 9. Fin material 10. Brazing sheet

Claims (4)

[Claims] 1. Mn 0.3-2.0 wt%, Zn 0.5-3.0 wt
%, Ca 0.01 to 0.3 wt%, In 0.005 to 0.1 wt%, Cu
0.05 to 0.6 wt%, Si 0.1 to 1.2 wt%, Mg 0.1 to 1.0
wt%, Cr0.05-0.3 wt%, Zr0.05-0.3 wt%, Ti
An aluminum alloy fin material for vacuum brazing, containing 0.005 to 0.2 wt% and Fe 0.3 wt% or less, and the balance being Al. 2. Mn 0.3-2.0 wt%, Zn 0.5-3.0 wt
%, Ca 0.01 to 0.3 wt%, In 0.005 to 0.1 wt%, Cu
0.05 to 0.6 wt%, Si 0.1 to 1.2 wt%, Mg 0.1 to 1.0
wt%, Cr0.05-0.3 wt%, Zr0.05-0.3 wt%, Ti
0.005 to 0.2 wt%, Fe 0.3 wt% or less, and further one of Ni 3.0 wt% or less, V 1.0 wt% or less, Co 0.5 wt% or less, Hf 0.5 wt% or less, W 0.5 wt% or less, or An aluminum alloy fin material for vacuum brazing, comprising two or more kinds, and the balance being Al. 3. Mn 0.3-2.0 wt%, Zn 0.5-3.0 wt
%, Ca 0.01 to 0.3 wt%, In 0.005 to 0.1 wt%, Cu
0.05 to 0.6 wt%, Si 0.1 to 1.2 wt%, Mg 0.1 to 1.0
wt%, Cr0.05-0.3 wt%, Zr0.05-0.3 wt%, Ti
An aluminum alloy ingot containing 0.005 to 0.2 wt% and Fe 0.3 wt% or less and the balance being Al at 420 to 560 ° C.
~ After homogenizing for 24 hours, hot rolling and then cold rolling 0.5 ~ 6 at 380 ~ 450 ℃
A method for producing an aluminum alloy fin material for vacuum brazing, comprising performing intermediate annealing for one time or more, and then performing cold rolling at a cold rolling rate of 20 to 40% after the final intermediate annealing. 4. Mn 0.3-2.0 wt%, Zn 0.5-3.0 wt
%, Ca 0.01 to 0.3 wt%, In 0.005 to 0.1 wt%, Cu
0.05 to 0.6 wt%, Si 0.1 to 1.2 wt%, Mg 0.1 to 1.0
wt%, Cr0.05-0.3 wt%, Zr0.05-0.3 wt%, Ti
0.005 to 0.2 wt%, Fe 0.3 wt% or less, and further one of Ni 3.0 wt% or less, V 1.0 wt% or less, Co 0.5 wt% or less, Hf 0.5 wt% or less, W 0.5 wt% or less, or Upon homogenizing an aluminum alloy ingot containing two or more kinds and the balance being Al at 420 to 560 ° C. for 1 to 24 hours, hot rolling and then cold rolling are performed.
Aluminum alloy for vacuum brazing, characterized by performing intermediate annealing at a temperature of 380 to 450 ° C for 0.5 to 6 hours at least once, and performing cold rolling at a cold rolling rate of 20 to 40% after the final intermediate annealing. Fin material manufacturing method.