JP2951585B2 - Manufacturing method of aluminum alloy fin material for brazing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a highly heat-conductive aluminum alloy fin material which can be reduced in thickness.
In particular, the present invention relates to a method for manufacturing a fin material used for a radiator, a heater, a condenser, and the like of an automotive heat exchanger manufactured by a brazing method.

[0002]

2. Description of the Related Art Most heat exchangers for automobiles use Al or Al alloy and are manufactured by a brazing method. Usually, an Al-Si brazing material is used as the brazing material, and is brazed by heating to a high temperature of about 600 ° C. For example, as shown in FIG. 1, a heat exchanger such as a radiator integrally forms thin fins 20 formed into a corrugated shape between a plurality of flat tubes 10, and both ends of the flat tubes 10 are connected to a header 30. The high-temperature refrigerant is opened from the space on one tank side to the space on the other tank 40 side through the flat tube 10, and the heat is exchanged between the tube 10 and the fin 20. The low temperature refrigerant is circulated again.

[0003] In recent years, heat exchangers have been reduced in size and weight, and therefore, it has been desired to improve the heat efficiency of the heat exchanger and, consequently, the heat conductivity of the fin material. A fin material having an alloy component close to pure aluminum and having excellent thermal conductivity has been proposed. However, since the fin material has insufficient strength, there is a problem that when the fin material is thinned, the fin is crushed at the time of assembling the heat exchanger or broken during use. Therefore, an attempt was made to add Mn effective for improving the strength of the fin, but there was a problem that Mn was re-dissolved in the brazing step to lower the thermal conductivity of the fin. For these reasons, an Al-Ni alloy fin material having enhanced strength without impairing the thermal conductivity has been proposed (Japanese Patent Laid-Open No. 6-1166).
No. 68).

[0004]

However, as this Al-Ni alloy fin material becomes thinner, the fins melt during brazing, and several fins are united into one. As a result, a new problem arises in that the pressure resistance of the heat exchanger is reduced. As the melting of the fins progresses, the brazing material is sucked into the gaps between the fins, and the plurality of fins unite, so that the fins and the brazing material cannot be distinguished (see FIG. 3D).

The present inventors have studied the method of preventing the Al-Ni alloy fin from melting, and have found that the fin can be improved by selecting a hot rolling temperature, an intermediate annealing temperature, and the like during production. To complete the present invention.
An object of the present invention is to provide a method for producing an Al—Ni alloy fin material having improved brazing properties.

[0006]

According to the first aspect of the present invention,
Si exceeding 0.005 wt% and 0.8 wt% or less, exceeding 0.03 wt% 2.
To manufacture aluminum alloy fin material containing less than 5 wt% Fe, more than 0.1 wt% Ni and less than 2.0 wt% Ni and the balance of aluminum and unavoidable impurities, after semi-continuous casting, the temperature exceeded 470 ° C. A method for producing an aluminum alloy fin material for brazing, characterized in that hot rolling is performed without heating, and intermediate annealing is performed at a sheet thickness at which a final cold rolling reduction is 7 to 19%.

[0007] The invention described in claim 2 is more than 0.005 wt%
0.8 wt% or less of Si, 0.03 wt% or more and 2.5 wt% or less of Fe,
Ni more than 0.1wt% and less than 2.0wt%, more than 0.03wt% 0.3w
To produce an aluminum alloy fin material containing t% or less of Zr and the balance of aluminum and unavoidable impurities, after semi-continuous casting, hot rolling was performed without heating to a temperature exceeding 470 ° C. Cold rolling rate is 7 ~
This is a method for producing an aluminum alloy fin material for brazing, wherein intermediate annealing is performed at a sheet thickness of 19%.

[0008] The invention according to claim 3 has a content exceeding 0.005 wt%.
0.8 wt% or less of Si, 0.03 wt% or more and 2.5 wt% or less of Fe,
Contains more than 0.1 wt% Ni and less than 2.0 wt%
In manufacturing an aluminum alloy fin material containing one or more of Zn of not more than t%, In of not more than 0.3 wt%, and Sn of not more than 0.3 wt%, the balance being aluminum and unavoidable impurities. An aluminum alloy for brazing, characterized in that after continuous casting, hot rolling is performed without heating to a temperature exceeding 470 ° C., and intermediate annealing is performed at a sheet thickness in which the final cold rolling reduction is 7 to 19%. This is a method for manufacturing a fin material.

[0009] The invention according to claim 4 has a content exceeding 0.005 wt%.
0.8 wt% or less of Si, 0.03 wt% or more and 2.5 wt% or less of Fe,
Ni more than 0.1wt% and less than 2.0wt%, more than 0.03wt% 0.3w
t% or less Zr, 2.0 wt% or less Zn, 0.3w
In order to manufacture an aluminum alloy fin material containing at least one of In of less than t% and Sn of less than 0.3 wt% and the balance of aluminum and unavoidable impurities, 470 ° C after semi-continuous casting. A method for producing an aluminum alloy fin material for brazing, wherein hot rolling is performed without heating to a temperature exceeding the temperature, and intermediate annealing is performed at a sheet thickness at which a final cold rolling reduction is 7 to 19%. .

The invention according to claim 5 is that the ingot is homogenized at 380 to 460 ° C. for 24 hours or less, and the intermediate annealing is performed at 280 to 470 ° C. for 30 minutes to 12 hours. The method for producing a brazing aluminum alloy fin material according to any one of claims 1 to 4, characterized in that:

The invention according to claim 6 is the aluminum alloy for brazing according to any one of claims 1 to 5, wherein a cold rolling reduction before final intermediate annealing is 95% to 99.5%. This is a method for manufacturing a fin material.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the action of alloying elements in the aluminum alloy used in the present invention and the reasons for limiting the content thereof will be described. When Si coexists with Fe or Ni,
Promotes the precipitation of Ni, increases the amount of intermetallic compounds contributing to dispersion strengthening, and improves the strength. In addition, the precipitation of Fe or Ni reduces the amount of Fe or Ni dissolved in the fin material and improves the thermal conductivity. If the Si content is less than 0.005 wt%, the effect cannot be sufficiently obtained. If the Si content exceeds 0.8 wt%, the effect of accelerating the precipitation of Fe and Ni is not changed, but the strength cannot be improved much. In addition, the amount of solid solution of Si increases and the thermal conductivity sharply decreases. Therefore, the content of Si should be more than 0.005 wt% and 0.8 wt% or less. Desirable content of Si is 0.03-0.2 wt% if thermal conductivity is important
% And 0.3-0.7 wt% when emphasis is placed on strength. still,
When Si is increased in the range of 0.3 to 0.8 wt%, the improvement in strength by solid solution hardening of Si is larger than the decrease in thermal conductivity.

[0013] Fe forms an intermetallic compound and contributes to improvement in strength. If the content is less than 0.03% by weight, the effect cannot be sufficiently obtained, and if it exceeds 2.5% by weight, the formability is reduced and the corrugating of the fin becomes difficult. Therefore, the content of Fe should be more than 0.03 wt% and not more than 2.5 wt%. Ni contributes to improving strength by distributing fine intermetallic compounds in the alloy. In particular, when coexisting with Si, it becomes very easy to precipitate and contributes to improvement in strength without lowering thermal conductivity. If the content is less than 0.1% by weight, the effect cannot be sufficiently obtained. If the content exceeds 2.0% by weight, the formability is reduced and it becomes difficult to form corrugated fins. Therefore
Ni should be more than 0.1wt% and less than 2.0wt%. Zr increases the recrystallized grains of the fin generated during the brazing heating. When the recrystallized grains are small, the fins are likely to be crushed due to the diffusion of the brazing grains during brazing heating. If Fe is contained in a relatively large amount, recrystallized grains may be fine. Zr is preferably added in such a case. If the content is less than 0.03 wt%, the effect cannot be sufficiently obtained, and if it exceeds 0.3 wt%, the ingot is broken at the time of casting. Therefore, Zr should be more than 0.03 wt% and not more than 0.3 wt%. From the viewpoint of thermal conductivity, 0.2 wt% or less is desirable.

In the aluminum alloy used in the present invention,
In addition to the above alloy elements, Zn of less than 2.0 wt%, 0.3 wt%
One or more of the following In and 0.3 wt% or less of Sn may be added. These alloying elements are added to impart a sacrificial anode effect to the fin material. If each of the above amounts is added, the thermal conductivity decreases. Of the above elements, In is preferred from the viewpoint of thermal conductivity, and Zn is preferred from the viewpoint of cost.
Is recommended. Inevitable impurities in the aluminum alloy used in the present invention include Ti and B added for refining the ingot structure. Each of these elements is 0.03
If it is less than wt%, there is no problem.

The above are the reasons for limiting the alloy composition of the aluminum alloy used in the production method of the present invention. These are alloys that have been proposed in recent years. In the present invention, in producing these alloy fins in the steps of semi-continuous casting, facing, homogenizing treatment, hot rolling, cold rolling, and annealing, heating is performed to a temperature exceeding 470 ° C. after semi-continuous casting. It is characterized by performing hot rolling without heat treatment and performing intermediate annealing at a sheet thickness at which the final cold rolling reduction is 7 to 19%.
Heat at 380 to 460 ° C for 24 hours or less and perform intermediate annealing.
It is also characterized by heating at 280 to 470 ° C for 30 minutes to 12 hours. Further, the cold rolling reduction before final intermediate annealing is 95 to 99.5%.
It is also a feature.

The manufacturing method of the present invention aims at preventing the above-mentioned melting of the fin. First, a description will be given of the results of an investigation conducted by the inventors on fin melting in order to solve the problem. First, we examined what kind of alloy this fin melts.The fin melt did not occur in the conventional Al-Mn alloy fins. (Compared with fins of the same thickness and the same amount of droop). In addition, it was found that even when the thickness of the fin is large, the phenomenon is unique even when the thickness of the Al-Ni alloy is reduced. Furthermore, it was also found that the fins were likely to be formed in the portion where the interval between the fins when corrugated was narrow. When investigating the phenomenon further based on these, when brazing the heat exchanger, the thermal expansion of the material occurs during the heating, and the fin is subjected to a force. It is clear that the thinner the fin, the greater the force per unit area. However, since this force is a force for bending the fin, it is proportional to the reciprocal of the square of the thickness of the fin. When brazing is performed under such stress, in the Al-Ni alloy, the fins are crushed at the fillet, and the space between the fins is narrow, and the surface tension of the melted braze Causes the fins to move, and several fins become one.

The production method of the present invention aims at preventing such melting of the fin, and the production method will be described below. The production method of the present invention is a method of producing fins in a semi-continuous casting, facing, homogenizing, hot rolling, cold rolling, and annealing process. If there is no such item, follow the usual method. First, there is no provision for semi-continuous casting.
The ingot may be manufactured by the usual DC casting or electromagnetic casting. The conditions for the facing are not specified. The face milling may be performed before the homogenizing treatment is performed also when heating is also performed in hot rolling, and may be performed either before or after the homogenizing treatment when performing the homogenizing treatment separately. In the case of electromagnetic casting, no facing is required. The homogenization treatment may be performed also as heating for hot rolling or may be performed separately without also heating for hot rolling, but the temperature condition of the present invention is very low, It is more efficient to perform the heating also. Homogenization temperature is 4
Do not heat above 70 ° C. The alloy ingot of the present invention manufactured by the semi-continuous casting method has a solid solution of elements such as Ni in supersaturation, and this is precipitated as an intermetallic compound by a homogenization treatment. The intermetallic compound becomes coarse, and melting is likely to occur.

There are two purposes for making the intermetallic compound containing Ni fine in order to prevent melting. One is to coarsen the recrystallized grains generated at the time of brazing and to prevent a decrease in the strength of the fin caused by grain boundary diffusion. The other is to disperse the Ni-containing intermetallic compound finely and densely so that the Si element which has entered by diffusion from the brazing alloy during brazing heating is taken into the intermetallic compound to prevent melting. Here, the object of the present invention is achieved as long as the homogenization treatment condition is not heated to a temperature exceeding 470 ° C. Distributed. The time is preferably within 24 hours in consideration of economy. The lower limit of the time is 0 hour. This is when semi-continuous ingots are industrially heated,
This is because it takes time to raise the temperature, so that precipitation occurs during the temperature increase. Considering precipitation during heating, the rate of
10-200 ° C / h is desirable. The conditions for the homogenization treatment of the present invention have been described above, and the rate of temperature rise in the homogenization treatment is 20 to 100 ° C./h.
It is the most desirable and recommended condition to set the temperature at 400 to 460 ° C. for 30 minutes to 12 hours from the viewpoint of economy and distribution of the intermetallic compound. Hot rolling may be performed by a usual method. However, when heating for hot rolling is performed separately from the homogenization treatment, the treatment temperature must not exceed 470 ° C. 470
If the temperature exceeds ℃, the intermetallic compound containing Ni becomes coarse and melting is likely to occur. There are no particular conditions other than these, and hot rolling may be performed by a normal method.

After hot rolling, cold rolling and annealing are performed.
Cold rolling is performed in several passes, and intermediate annealing is performed on the way. It is essential that the intermediate annealing be performed at a thickness at which the rolling reduction (final cold rolling reduction) in the cold rolling from the thickness at the time of the last intermediate annealing to the thickness of the fin becomes 7 to 19%. 7% final cold rolling rate
The reason defined above is that when cold rolling is performed on a thin material such as a fin, if the cold rolling reduction is small, the deformation tends to occur during rolling, and the thickness accuracy tends to vary. The reason for setting it to 19% or less is to prevent melting of the fin. Usually, when the final cold rolling ratio is set in consideration of the drooping characteristics of the alloy fins of the present invention and the diffusion state of the wax in the fins at the fillet portion, the final cold rolling reduction is 40% or less. Normal. The reason why the content is set to 19% or less is related to the fact that the heating temperature in the homogenization treatment is limited and the Ni-containing intermetallic compound is finely and densely distributed. That is, by lowering the final cold rolling reduction and distributing the intermetallic compound finely and densely, the sub-grain boundaries generated at the stage before the recrystallization of the fins during the brazing heating are unclear. You do it. As a result, Si
Is diffused over the entire surface and reacts with all the intermetallic compounds finely and densely distributed over the entire surface, thereby preventing the intrusion of Si into the inside of the fin. From the above, the final cold rolling rate is determined to be 7 to 19%, but considering the ease of rolling, the final cold rolling rate exceeding 10%, and considering that the effect of preventing fusion is particularly exhibited, 17% or less. The final cold rolling reduction is particularly recommended.

The intermediate annealing is performed using a batch type furnace. The conditions are 280 to 470 ° C for 30 minutes to 12 hours. If the temperature is less than 280 ° C. and the time is less than 30 minutes, recrystallization may not be completed and may not fulfill the role of annealing. If the temperature exceeds 470 ° C., the Ni-containing intermetallic compound becomes coarse, and melting tends to occur. Treatment over 12 hours is not economical. During annealing, Ni-containing intermetallic compounds are not coarsened and recrystallization is completed.
30 minutes to 4 hours are particularly recommended. The above are the conditions of the final intermediate annealing and the final cold rolling reduction. However, after hot rolling, intermediate annealing may be performed on the way to the final annealed sheet thickness by cold rolling. In this case, when a batch type furnace is used, the upper limit temperature and time are set to the above conditions. When a continuous furnace is used, the heating is performed at 550 ° C. or less and within 3 minutes. Time 3
Within minutes, the Ni-containing intermetallic compound does not become coarse unless it exceeds 550 ° C. There is no particular lower limit. This is because it is not necessary to cause recrystallization in the intermediate annealing in the middle.

A method for more effectively carrying out the present invention is to set the cold rolling reduction before final intermediate annealing to 95% to 99.5%. By setting the cold rolling reduction to a high value exceeding 95%, the recrystallized grain size generated in the final intermediate annealing is made fine. The final cold rolling ratio of the present invention is small, and the final cold rolling is performed with a small sheet thickness, so that the tension control of the rolling is important, but if the crystal grain size is fine, the strength of the sheet increases, This is because breakage of the fin during rolling becomes difficult to occur. Further, if the recrystallized grain size after the final intermediate annealing is fine, strain is likely to be uniformly distributed at the time of final cold rolling, and there is an effect of uniformly preventing melting during brazing. The upper limit of the cold rolling ratio is set to 99.5%. This is because a cold rolling ratio exceeding 99.5% may cause edge cracking during cold rolling. The cold rolling may be performed in one pass, or may be performed in several passes. The plate thickness of the fin manufactured in the present invention is 0.03 to
The effect of the invention is well exhibited when the thickness is reduced to about 0.1 mm, particularly to 0.07 mm or less. The heat exchanger using the fin of the present invention is a radiator for automobiles, a condenser, and a heat exchanger.
Examples thereof include a tar, an evaporator, and an oil cooler, but are not limited thereto. Further, the method of brazing the fins manufactured by the present invention uses a conventionally performed non-corrosive flux brazing, flux brazing, vacuum brazing, or Al-Si-Cu-Zn alloy brazing material. Any brazing method such as attachment (Japanese Patent Application Laid-Open No. 7-88634) can be applied.

[0022]

The present invention will be described below in more detail with reference to examples. (Example 1) An aluminum alloy having a composition of Nos. A to J shown in Table 1 was cast by a semi-continuous casting method, and the cross-sectional dimension was 60%.
× 400 to 1000 mm plate-shaped ingot was obtained. Next, this was divided into 2 to 5 in the longitudinal direction, and both sides were chamfered by 5 mm. The facing material was homogenized, and after the homogenization treatment, hot rolling was started at that temperature. The obtained hot-rolled plate was divided in the length direction, and this was cold-rolled while performing intermediate annealing to produce a fin material having a thickness of 55 μm. Homogenization, hot rolling, cold rolling,
Intermediate annealing during cold rolling varied conditions. Table 2 shows the manufacturing process.

Each of the obtained fin materials was subjected to a melting test and a hanging test. Further, the strength and the electrical conductivity were examined. The melting test was performed using two brazing sheets as shown in FIG.
A fin material 70 of 22 mm width corrugated is sandwiched between 60,
After the application of the fluoride-based flux, the brazing was heated by heating, and the melting state of the fins after the brazing was examined. In FIG. 2, reference numeral 70 denotes a wire 70 for fixing the two brazing sheets 60. The brazing sheet has a 4045 alloy clad thickness of 10%.
A brazing sheet for tubes of 0.25 mm was used. The pitch of the corrugate is set to 1/2 of the normal pitch so that the difference can be easily seen. Brazing heating was performed under the conditions of heating at 600 ° C. for 5 minutes in a nitrogen gas. The evaluation criteria of the fin melting state will be described with reference to FIG. 3 (metal structure photograph). FIG. 3 (a) shows that the fins are not melted at all ◎, FIG. 3 (b) shows that the fins are just before melting occurs at a narrow space between the fins, and FIG. In the case where the melting occurred at a portion where the interval was narrow, the result was evaluated as “△”. In FIG. In the hanging test, the fin material was protruded, brazed and heated with a cantilever having a length of 50 mm, and the amount of hanging was measured and evaluated. The conductivity was examined as an index of thermal conductivity. When the conductivity of the fin is improved by 5% IACS, the thermal efficiency of the heat exchanger is improved by about 1%. Table 3 shows the results.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

As is clear from Table 3, the sample of the present invention (N
o.1 to 10) do not melt, tensile strength, electrical conductivity,
It also had excellent droop resistance. On the other hand, No. 11 and No. 12 of the conventional products (containing no Ni) did not melt the fin, but any of the tensile strength, the electrical conductivity and the drooping resistance were reduced. In Comparative Examples Nos. 13, 14, 15, and 17, the temperatures of the homogenization treatment and the hot rolling were too high, and the final cold rolling reduction was too large, so that the melting proceeded extremely. Nos. 16, 19 and 20 melted because the homogenization temperature was too high. In No. 18, melting was extremely advanced because the final cold rolling reduction was large. Nos. 14 and 17 had a particularly large final cold rolling reduction, and thus had a low droop resistance.

(Example 2) DC casting (400 mm thick) of No. K of 6 aluminum alloys shown in Table 1
And the both sides of the ingot are chamfered (one side 10mm), and after homogenization,
It was hot rolled at the same temperature and wound into a coil. The obtained hot-rolled material was divided and cold-rolled with intermediate annealing to produce a fin material having a thickness of 60 μm. Homogenization treatment, hot rolling, intermediate annealing, and cold rolling were performed under various conditions.

With respect to each of the obtained fin materials, a melting test and a hanging test were performed in the same manner as in Example 1. Further, the tensile strength and the electrical conductivity after the brazing and heating of the sample of the present invention were examined. Table 4 shows the results together with the production conditions.

[0030]

[Table 4]

As is clear from Table 4, the product of the present invention (No.
Nos. 21 to 25) did not melt any of the fins and had excellent droop resistance. The tensile strength after brazing is 135MP
a) The conductivity was 53% IACS and all showed good values. On the other hand, No. 26 and 27 of the comparative example products were too high in the temperature of the homogenization treatment and hot rolling and the final cold rolling reduction was large. Since the temperature was extremely high, the melting of the fins proceeded very much in each case. No. 29 melted because the final cold rolling reduction was large. In No. 30, the melting progressed very much because the final cold rolling reduction was large and the cold rolling reduction before final intermediate annealing was low. No. 27 had a particularly large final cold rolling reduction, and thus had a reduced droop resistance.

[0032]

As described above, according to the present invention,
The brazing property of Al-Ni fin material with high strength and excellent thermal conductivity is improved, and has a remarkable industrial effect.

[Brief description of the drawings]

FIG. 1 is a partially sectional perspective view showing a radiator.

FIG. 2 is an explanatory diagram of a melting test method.

FIG. 3 is a metallographic photograph showing evaluation criteria for the fin melting state.

[Explanation of symbols]

 10 Flat tube 20 Fin 30 Header 40 Tank brazing material 60 Brazing sheet 70 Wire for fixing brazing sheet

Claims (6)

(57) [Claims] 1. The method of claim 1 wherein the Si content is more than 0.005 wt% and 0.8 wt% or less.
More than wt% and less than 2.5wt% Fe, more than 0.1wt% and 2.0wt%
In producing an aluminum alloy fin material containing the following Ni and the balance of aluminum and unavoidable impurities, after semi-continuous casting, hot rolling was performed without heating to a temperature exceeding 470 ° C, and final cold rolling was performed. Rolling rate 7-19%
A method for producing an aluminum alloy fin material for brazing, comprising performing intermediate annealing at a sheet thickness of: 2. The method according to claim 1, wherein the Si content is more than 0.005 wt% and 0.8 wt% or less.
More than wt% and less than 2.5wt% Fe, more than 0.1wt% and 2.0wt%
The following Ni, containing more than 0.03wt% and less than 0.3wt% Zr,
To produce an aluminum alloy fin material consisting of the remaining aluminum and unavoidable impurities, after semi-continuous casting, hot rolling is performed without heating to a temperature exceeding 470 ° C, and the final cold rolling rate is 7 to 19%. A method for producing an aluminum alloy fin material for brazing, comprising performing intermediate annealing at a sheet thickness of: 3. The method according to claim 3, wherein the content of Si is more than 0.005 wt% and 0.8 wt% or less.
More than wt% and less than 2.5wt% Fe, more than 0.1wt% and 2.0wt%
The following Ni is contained, and Zn of less than 2.0 wt%, 0.3 wt%
In producing an aluminum alloy fin material containing one or more of the following In, 0.3 wt% or less of Sn, and the balance of aluminum and unavoidable impurities,
Aluminum for brazing, characterized in that after semi-continuous casting, hot rolling is performed without heating to a temperature exceeding 470 ° C., and intermediate annealing is performed at a sheet thickness in which the final cold rolling reduction is 7 to 19%. Manufacturing method of alloy fin material. 4. An alloy containing 0.03 wt% or more of Si and 0.03 wt% or less.
More than wt% and less than 2.5wt% Fe, more than 0.1wt% and 2.0wt%
The following Ni, containing more than 0.03wt% and less than 0.3wt% Zr,
In addition, Zn of less than 2.0wt%, In of less than 0.3wt%, 0.3wt%
In producing an aluminum alloy fin material containing one or more of the following Sn and the balance of aluminum and unavoidable impurities, after semi-continuous casting,
Hot rolling without heating to a temperature exceeding ℃,
A method for producing an aluminum alloy fin material for brazing, wherein intermediate annealing is performed at a sheet thickness at which a final cold rolling reduction is 7 to 19%. 5. The ingot is homogenized at 380 to 460 ° C. for 24 hours.
Heating condition for 30 hours or less, intermediate annealing at 280-470 ° C 30
The method for producing an aluminum alloy fin material for brazing according to any one of claims 1 to 4, wherein the heating is performed under conditions of heating for minutes to 12 hours. 6. The cold rolling reduction before final intermediate annealing is 95% to 9%.
The method for producing an aluminum alloy fin material for brazing according to any one of claims 1 to 5, wherein the content is 9.5%.