JPH05171326A - Aluminum alloy fin material for low temperature brazing and its production - Google Patents

Abstract

PURPOSE:To improve strength and thermal conductivity without deteriorating the brazeability of a fin material for automobile heat exchanger such as radia tor, heater, and condenser, to be subjected to brazing at a low temp. CONSTITUTION:At the time of producing an Al alloy fin material by subjecting an ingot of an aluminum alloy having a composition consisting of, by weight, 0.03-0.8% Si, 0.05-1.0% Fe, 0.3-0.6% Mn, and the balance Al with inevitable impurities to homogenizing treatment, hot rolling, cold rolling, and annealing stages, the Al alloy fin material where the specific resistivity values before and after brazing are regulated to <=37nOMEGAm, respectively, can be obtained by performing heating, in the case where a stage of heating up to a temp. exceeding 500 deg.C is contained, for >=4hr in the aggregate at the time when a temp. of <=500 deg.C is reached in the final stage exceeding 500 deg.C and also at 380-500 deg.C in the subsequent stage and also by performing heating, in the case where a stage of heating up to a temp. exceeding 500 deg.C is not contained, for >=4hr in the aggregate at 380-500 deg.C in the stages after homogenizing treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a high strength for brazing at a temperature of 500 ° C. or less as fins for radiators, heaters, condensers, etc.
The present invention relates to an aluminum alloy fin material for low temperature brazing having high thermal conductivity and a method for manufacturing the same.

[0002]

2. Description of the Related Art Most heat exchangers for automobiles are made of Al and Al.
The alloy is used and manufactured by a brazing method. Usually, an Al-Si alloy brazing material is used for brazing, and therefore brazing is performed at a high temperature of about 600 ° C. In a heat exchanger such as a radiator, for example, as shown in FIG. 1, thin fins (2) processed into a corrugated shape are provided between a plurality of flat tubes (1), and headers (3) are provided at both ends of the flat tubes (1). The tank (4) is attached through the flat tube (1), and both ends of the flat tube (1) are opened in the space formed by the header (3) and the tank (4). A high-temperature refrigerant is sent from the space through the flat tube (1) to the space in the other tank (4), and the refrigerant that has become low temperature by heat exchange in the tubes (1) and fins (2) is circulated again. Is.

[0003]

In recent years, heat exchangers are becoming lighter and smaller, and for that purpose, it is necessary to improve the heat efficiency of the heat exchanger, and it is desired to improve the heat conductivity of the constituent materials. There is. In particular, there is a strong demand for improvement of the thermal conductivity of the fin material, and various studies have been conducted, and a fin material having an improved purity of an aluminum alloy has been proposed as a high thermal conductivity fin. However, the high-purity aluminum fin has a drawback that its strength is insufficient, and a fin material improved in thermal conductivity with the strength of the existing fin material has not yet been developed. This requires the addition of alloying elements to maintain the strength of conventional products, but as the final process of products,
Since there is brazing that is heated up to around 600 ° C, the elements added to the alloy during brazing heating will re-dissolve and hinder the thermal conductivity.

[0004]

As a result of various investigations in view of this, the present inventors have found that in order to develop a fin material having high strength and thermal conductivity after brazing, conventional fining should be used instead of conventional brazing.
We thought that the problem could be solved by developing a fin material suitable for brazing with a low brazing temperature.

Here, brazing in which the brazing temperature is low is a brazing method developed from the fact that the demand for lower brazing temperature has been increasing in recent years due to the reduction of brazing cost. By lowering the brazing temperature, various advantages such as reduction of brazing time, reduction of cost of brazing furnace, and improvement of durability of brazing furnace are produced. As a brazing filler metal for low temperature brazing currently being developed, if the melting point is 500 ° C. or lower, for example, pure Zn, Zn-0 to
28% Al alloy, Zn-Al alloy, Zn-Cd alloy,
There are Sn-Zn alloys, Sn-Pb alloys and the like. However, considering the corrosion resistance of the heat exchanger after brazing, Zn-Al
The system alloy brazing material is the most effective. As a result of further studies, the present invention has developed an aluminum alloy fin material for low temperature brazing, which is suitable for the above brazing method and has excellent strength and thermal conductivity after brazing, and a method for producing the same.

That is, one of the fin materials of the present invention is Si0.03
0.8wt% (hereinafter wt% is abbreviated as%), Fe0.05-1.0%,
It is characterized in that it contains 0.3 to 0.6% of Mn, the balance is Al and unavoidable impurities, and the specific resistance value before and after brazing is 37 nΩm or less.

Another one of the fin materials of the present invention is Si0.
03-0.8%, Fe0.05-1.0%, Mn 0.3-0.6% included, Cr 0.3% or less, Zr 0.3% or less, Ni 0.3%
Hereafter, one or two or more of Ti 0.3% or less, Mo 0.3%, and Co 0.3% or less are included, and the balance Al and unavoidable impurities are included, and the specific resistance value before and after brazing is 37 nΩm.
It is characterized by the following.

Another one of the fin materials of the present invention is Si0.
03-0.8%, Fe 0.05-1.0%, Mn 0.3-0.6%, Cu 0.5% or less, Mg 0.5% or less 1 type or 2 types, and the balance Al and inevitable impurities. The specific resistance before and after attachment is 37 nΩm or less.

Another one of the fin materials of the present invention is Si0.
03-0.8%, Fe0.05-1.0%, Mn 0.3-0.6% included, Cr 0.3% or less, Zr 0.3% or less, Ni 0.3%
Below, one or more of 0.3% or less of Ti, 0.3% or less of Mo, 0.3% or less of Co and 0.5% or less of Cu, 0.5% of Mg
Contains one or two of the following, consisting of balance Al and unavoidable impurities, and has a specific resistance value of 37n before and after brazing.
It is characterized by being less than Ωm.

Next, one of the methods for producing the fin material of the present invention is as follows:
Si0.03-0.8%, Fe0.05-1.0%, Mn0.3-0.6
%, The balance of Al and the unavoidable impurities in the aluminum alloy ingot is heated to a temperature of more than 500 ° C. to produce a fin material by homogenization, hot rolling, cold rolling and annealing. When the temperature reaches 500 ° C or lower in the last step above 500 ° C, in the subsequent steps, heat at a temperature range of 380 to 500 ° C for a total of 4 hours or more, and heat to a temperature above 500 ° C. If there is no step to be performed, 380 to 5
It is characterized by heating for a total of 4 hours or more in the temperature range of 00 ° C and setting the specific resistance value before and after brazing to 37 nΩm or less.

Another method of manufacturing the fin material of the present invention is as follows: Si 0.03 to 0.8%, Fe 0.05 to 1.0%, Mn 0.3 to
0.6% included, Cr 0.3% or less, Zr 0.3% or less,
Ni 0.3% or less, Ti 0.3% or less, Mo 0.3% or less, C
o 0.3% or less of 1 type or 2 or more types, balance Al
When producing a fin material by homogenizing, hot rolling, cold rolling, and annealing steps of an aluminum alloy consisting of unavoidable impurities and 500 ° C, if there is a step to heat it to a temperature above 500 ° C. Last process over 500 ℃
When the following is reached, 380 to 5
If there is no step of heating in the temperature range of 00 ° C for a total of 4 hours or more and heating to a temperature of more than 500 ° C, in the process after the homogenization treatment, the total temperature range of 380 to 500 ° C is 4
Heat for more than an hour and set the specific resistance before and after brazing to 3
The feature is that it is 7 nΩm or less.

Further, one of the methods for manufacturing the fin material of the present invention is
Si0.03-0.8%, Fe0.05-1.0%, Mn0.3-0.6
%, And further contains one or two of 0.5% or less of Cu and 0.5% or less of Mg, and the balance Al and unavoidable impurities. An aluminum alloy ingot is homogenized, hot-rolled, cold-rolled, When the fin material is manufactured by the annealing step, if there is a step of heating to a temperature higher than 500 ° C, when it reaches 500 ° C or lower of the final step of higher than 500 ° C, 380 to 500 If you do not have a step of heating in the temperature range of ℃ for a total of 4 hours or more and a temperature of over 500 ℃, in the step after homogenization treatment, heat in the temperature range of 380 to 500 ℃ for a total of 4 hours or more. However, the specific resistance before and after brazing is 37 nΩm or less.

Further, one of the manufacturing methods of the fin of the present invention is S
i 0.03 to 0.8%, Fe 0.05 to 1.0%, Mn 0.3 to 0.6%
Containing Cr, 0.3% or less, Zr 0.3% or less, Ni
0.3% or less, Ti 0.3% or less, Mo 0.3% or less, Co 0.
1 or 2 or more of 3% or less and Cu 0.5% or less,
When manufacturing a fin material by homogenizing, hot rolling, cold rolling, annealing an aluminum alloy ingot containing one or two of Mg 0.5% or less and the balance Al and unavoidable impurities If there is a step of heating to a temperature above 500 ° C, the last step above 500 ° C is 500
℃ ~ 380 ~
If you do not have a step of heating to a temperature of 500 ° C for a total of 4 hours or more and a temperature of more than 500 ° C, in the steps after homogenization treatment, a temperature of 380 to 500 ° C for a total of 4 hours or more. Heat and set the specific resistance value before and after brazing
It is characterized by being set to 37 nΩm or less.

[0014]

First, the reason why the alloy composition of the fin material is limited as described above in the present invention will be explained.

Si contributes to the improvement of the strength and the thermal conductivity, and has the effect of promoting the precipitation of Mn. Therefore, the intermetallic compound which contributes to the dispersion strengthening is increased and the strength is improved.
Further, by promoting the precipitation of Mn, the solid solution element in the fin material is reduced and the thermal conductivity is improved. However, the reason why the Si content is limited to 0.03 to 0.8% is that the effect is not sufficient below the lower limit, and if the upper limit is exceeded, the diffusion of braze during brazing heating becomes large and the brazeability deteriorates.

Fe forms an intermetallic compound with Mn and contributes to the improvement of strength. Therefore, the Fe content is 0.05 to
The reason why the amount is limited to 1.0% is that if the amount is less than the lower limit, the effect is insufficient, and if the amount exceeds the upper limit, a large amount of coarse crystallized substances are produced during casting,
This is because the recrystallized grain size at the time of brazing heating becomes small and the brazing property deteriorates.

Mn distributes a fine intermetallic compound in the alloy to improve the strength. Therefore, the Mn content is 0.3
The reason why the content is limited to 0.6% is that the effect is not sufficient when the content is less than the lower limit and the thermal conductivity is reduced when the content exceeds the upper limit.

In the present invention, Cr 0.3% or less, Zr 0.3
% Or less, Ni 0.3% or less, Ti 0.3% or less, Mo 0.3%
Hereinafter, one or more of Co 0.3% or less may be added. These have a function of improving strength by forming a fine intermetallic compound. Then each
If it is added in excess of 0.3%, the formability will deteriorate and the fins will crack during assembly.

In the present invention, Cu 0.5% or less, Mg 0.5
% Or less, one or two kinds may be added. These improve the strength mainly by solid solution hardening and precipitation hardening. However, all of these elements lower the thermal conductivity, and particularly Cu has a function of making the potential of the fin material noble. Therefore, if the content exceeds 0.5%, the sacrificial effect of the fin is reduced. Further, Mg exists as a solid solution state and as a fine precipitation phase of Mg ₂ Si and improves the strength, but if the content exceeds 0.5%, it reacts with the flux and brazing cannot be performed.

The above are the components of the fin material of the present invention, but elements other than the above, such as B added for refining the structure of the ingot, may be added if the content is 0.05% or less.

The fin material of the present invention must further have a specific resistance value of 37 nΩm or less before brazing and a specific resistance value of 37 nΩm or less after heating by brazing. The specific resistance value is an index showing the amount of solid solution element in the fin material, and the smaller this value is, the smaller the amount of solid solution element is, and it can be said that the fin has excellent thermal conductivity.

Conventionally, even if the solid solution state in the fin material before brazing is controlled by the precipitation treatment, the re-solid solution phenomenon occurs during the brazing heating, and most of the elements are in the solid solution state, resulting in heat conduction. It was thought that the heat conductivity could not be improved and the thermal conductivity was determined only by the alloy components. However, when the present inventors investigated the progress of re-solidification during the brazing heating process of the fin material, the above phenomenon occurred at around 600 ° C, but such re-solidification occurred at low temperature brazing at 500 ° C or less. It was found that the melting phenomenon hardly occurred. The present invention is based on such research. If the specific resistance value after brazing exceeds 37nΩm, the thermal conductivity of the fin will decrease, and if the specific resistance value before brazing exceeds 37nΩm, the specific resistance after brazing heating should be 37nΩm or less. It is difficult. Therefore, the specific resistance value of the fin material before brazing was 37 nΩm or less, and the specific resistance value after brazing heating was also 37 nΩm or less. The specific resistance of the conventional fin material is 46 nΩm or more after brazing.

Next, a method for manufacturing the fin material of the present invention will be described. The manufacturing method of the present invention has a step of heating the aluminum alloy ingot having the above composition to a temperature exceeding 500 ° C. when manufacturing the fin material by the steps of homogenizing treatment, hot rolling, cold rolling and annealing. If the temperature reaches 500 ° C or lower in the last process exceeding 500 ° C, in the subsequent process, heating is performed in the temperature range of 380 to 500 ° C for a total of 4 hours or more, and heating to a temperature in excess of 500 ° C. If it does not have 380 ~ 500 ℃ in the process after homogenization
The heating is performed in the temperature range of 4 hours or more in total.

As described above, the characteristic feature of the present invention is that the heating is performed in the temperature range of 380 to 500 ° C. for a total of 4 hours or more. During this period, the solid solution element is precipitated and the specific resistance value before brazing is 37 nΩm. The specific resistance after brazing and heating is set to 37nΩm. Here, the temperature range is set to 380 to 500 ° C because precipitation takes time and productivity decreases at temperatures below 380 ° C, and intermetallic compounds that precipitate below 380 ° C are less likely to occur during brazing. This is because it is easy to form a solid solution again and does not contribute much to the improvement of thermal conductivity. Further, when heating is performed at more than 500 ° C, not only the reduction of solid solution elements due to precipitation cannot be expected, but conversely re-dissolution of precipitated particles occurs, the amount of solid solution elements increases, and the thermal conductivity decreases. Therefore, the temperature range mentioned here means that the fin material being manufactured is in that temperature range, and it is not necessary to maintain the temperature at a constant temperature.

Here, when there is a step of heating to a temperature exceeding 500 ° C., the final step of 500 ° C. exceeding 500 ° C.
When the temperature reaches the following level, in the subsequent steps, heating above 500 ° C. causes re-dissolution of the precipitated particles, so even if the precipitation treatment is performed before that, a sufficient effect cannot be obtained. .. Therefore, the total time for the precipitation treatment should be 4 hours or more, counting from the time when the temperature range of 380 to 500 ° C is passed in the cooling process of the final step of exceeding 500 ° C.

If there is no step of heating to a temperature higher than 500 ° C., there is no problem as described above. Therefore, in all steps after the homogenization treatment, the time within the temperature range of 380 to 500 ° C. The total time should be 4 hours or more. The reason why the time is set to 4 hours or more is that a sufficient precipitation amount cannot be obtained when the time is less than 4 hours, and there is no upper limit of the holding time,
The longer the time, the more preferable, but it is usually 24 hours or less considering productivity.

The fin material of the present invention may be produced by any process as long as the above is satisfied, and the ingot may be an ingot produced by a normal DC casting method, and may or may not be subjected to a homogenizing treatment thereafter. Alternatively, only the heat treatment for hot rolling the ingot may be performed. Hot rolling may be performed by a conventional method, but hot rolling
Precipitation is easily promoted when the temperature is in the range of 380 to 500 ° C. The obtained hot-rolled coil is cold-rolled to form a fin material, but is annealed to adjust the temper. It does not matter if annealing is performed more than once.

The above is the method for producing the fin material of the present invention. When assembled as a heat exchanger, it is easiest to use it in combination with a heat exchanger tube material coated with a low melting point brazing material. In this case, the brazing is usually performed by a method such as a thermal spraying method, a hot dip plating method, an electroplating method, or a vapor deposition method. The plate thickness of the fin of the present invention is 120 μm or less.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples. Aluminum alloy ingots having the composition shown in Table 1 (thickness 400
mm) and then a homogenizing treatment shown in Table 2, a hot rolling shown in Table 3, a cold rolling shown in Table 4, and a manufacturing method including annealing, to produce a fin material having a plate thickness of 60 μm. The specific resistance value of this fin material was measured, and the obtained fin material was combined with the following tube material and header material to assemble the radiator shown in FIG.

JIS A3003 (Al-0.15% Cu-1.1% M
n) An alloy is used as a core material, and JIS A7072 (Al-1
% Zn) alloy clad at a rate of 10% to produce 0.4 mm and 1.2 mm thick coiled plate materials by the usual hot-pressing method, and using this coiled plate material, by hot dip plating, Z
An n-11% Al alloy brazing material (melting point 425 ° C) is plated on the surface opposite to the JISA7072 alloy clad layer to a thickness of 0.4 μm for a coiled plate material of 20 μm, and a 1.2 mm thick coiled plate material is formed. Was plated to a thickness of 80 μm. A coil-shaped plate material having a plate thickness of 0.4 mm was slittered in accordance with the size of the electric resistance welded pipe to form a strip material having a width of 35.0 mm. Using an ERW pipe manufacturing device, this strip is plated on the outer surface with a width of 16.0 mm and a thickness of 2.2 mm.
It was processed into an electric resistance welded pipe for the liquid passage pipe. Further, a coil-shaped plate material having a plate thickness of 1.2 mm was slittered to a width of 60 mm to obtain a header strip.

After degreasing the radiator thus assembled, a 10% concentration solution of a fluoride-based flux having a basic composition of AlF ₃ and CsF was applied, and a dew point of −40 ° C. maintained at a temperature of 450 ° C. in a nitrogen gas atmosphere. It was inserted into the furnace and brazed, and the joining condition after brazing was investigated. At the same time, the fin material was brazed and heated, and the tensile strength and the specific resistance value of the heated fin material were measured. Here, the specific resistance value is an index of thermal conductivity, and when the specific resistance value of the fin is reduced by 3 nΩm, the thermal efficiency of the heat exchanger is improved by about 1%.

As a comparative conventional method, the core material is JIS A30
03 alloy, JIS A7072 alloy and JIS A4343 (Al-7.5
% Si) alloy is hot-pressed onto each side of the core material, and a brazing sheet of the same structure is used to assemble the same radiator, and a 10% concentration solution of fluoride-based flux consisting of AlF ₃ and KF is applied. Then, brazing was performed in the same furnace as above at a temperature of 600 ° C, and the joining state after brazing was investigated. At the same time, the fin material was brazed and heated, and the tensile strength and the specific resistance value of the heated fin material were measured. The results are shown in Table 5.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

[Table 5]

As is clear from Table 5, the radiator of the present invention, which was subjected to low temperature brazing at 500 ° C. or lower, had a good joint between the fin and the electric resistance welded pipe, and the conventional example was 600 ° C. It was similar to the radiator that was brazed at high temperature. The tensile strength and the specific resistance value of the fin material after the brazing heating of the conventional example are not excellent in both, whereas the fin material of the present invention example is excellent in both the tensile strength and the specific resistance value. Indicates the value.

On the other hand, when the fin manufacturing process has a step of heating to a temperature higher than 500 ° C., when the temperature reaches 500 ° C. or lower of the final step of higher than 500 ° C., 380 to 500 ° C. is reached in the subsequent steps. If the total time for heating to the temperature range of 4 is less than 4 hours or if there is no step of heating to a temperature over 500 ℃, heat to the temperature range of 380-500 ℃ in the steps after homogenization treatment. Total time is 4
It can be seen that the fin material of the comparative example, which is less than the time, has a specific resistance value after brazing of more than 40 nΩm and is inferior in thermal conductivity.

[0040]

As described above, according to the present invention, when the obtained fin material is brazed at a low temperature of 500 ° C. or lower, the brazing property is not impaired, the fin material has high strength and excellent thermal conductivity. It has a remarkable industrial effect.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an automobile radiator with a part cut away.

[Explanation of symbols]

 1 Flat tube 2 Fins 3 Header 4 Tank

Claims (8)

[Claims] 1. Si0.03 to 0.8 wt%, Fe0.05 to 1.0 wt
%, Mn 0.3 to 0.6 wt%, balance Al and unavoidable impurities, and the specific resistance before and after brazing is 37 n
Aluminum alloy fin material for low temperature brazing, characterized by having an Ωm or less. 2. Si0.03-0.8 wt%, Fe0.05-1.0 wt
%, Mn 0.3 to 0.6 wt%, Cr 0.3 wt% or less, Zr 0.3 wt% or less, Ni 0.3 wt% or less, Ti 0.3 wt
% Or less, Mo 0.3wt% or less, Co 0.3wt% or less 1
Aluminum alloy fin material for low temperature brazing, characterized in that it contains at least one kind or more than two kinds, consists of balance Al and unavoidable impurities, and has a specific resistance value of 37 nΩm or less before and after brazing. 3. Si0.03 to 0.8 wt%, Fe0.05 to 1.0 wt
%, Mn 0.3 to 0.6 wt%, Cu 0.5 wt% or less and Mg 0.5 wt% or less 1 type or 2 types, and the balance Al and unavoidable impurities. Aluminum alloy fin material for low temperature brazing, characterized in that each is 37 nΩm or less. 4. Si0.03-0.8 wt%, Fe0.05-1.0 wt
%, Mn 0.3 to 0.6 wt%, Cr 0.3 wt% or less, Zr 0.3 wt% or less, Ni 0.3 wt% or less, Ti 0.3 wt
% Or less, Mo 0.3wt% or less, Co 0.3wt% or less 1
One or two or more, and one or two of Cu 0.5 wt% or less and Mg 0.5 wt% or less, and the balance Al and inevitable impurities, and the specific resistance before and after brazing is 37 nΩ.
An aluminum alloy fin material for low temperature brazing, characterized by having a size of m or less. 5. Si0.03 to 0.8 wt%, Fe0.05 to 1.0 wt
%, Mn 0.3 to 0.6 wt%, the balance of Al and inevitable impurities in the aluminum alloy ingot, by the process of homogenization, hot rolling, cold rolling, annealing, to produce a fin material, 500 ℃ When there is a step of heating to a temperature above 500 ° C, when the temperature reaches 500 ° C or lower of the last step above 500 ° C, in the subsequent steps, heating in a temperature range of 380 to 500 ° C for a total of 4 hours or more, When there is no step of heating to a temperature over 500 ° C, in the step after homogenization treatment, heating is performed in the temperature range of 380 to 500 ° C for a total of 4 hours or more. A method for producing an aluminum alloy fin material for low temperature brazing, which has a resistance value of 37 nΩm or less. 6. Si0.03 to 0.8 wt%, Fe0.05 to 1.0 wt
%, Mn 0.3 to 0.6 wt%, Cr 0.3 wt% or less, Zr 0.3 wt% or less, Ni 0.3 wt% or less, Ti 0.3 wt
% Or less, Mo 0.3wt% or less, Co 0.3wt% or less 1
Aluminum alloy ingot containing two or more kinds, and the balance Al and unavoidable impurities, is homogenized, hot-rolled,
When manufacturing fin material by cold rolling and annealing, if there is a step of heating to a temperature over 500 ° C, when it reaches 500 ° C or less of the last step over 500 ° C, the subsequent steps , If you do not have a step of heating in a temperature range of 380 to 500 ° C for a total of 4 hours or more and a temperature of more than 500 ° C, in the temperature range of 380 to 500 ° C in the steps after homogenization treatment. A method for producing an aluminum alloy fin material for low temperature brazing, wherein the specific resistance value before and after brazing is 37 nΩm or less, which is characterized by heating for a total of 4 hours or more. 7. Si0.03-0.8 wt%, Fe0.05-1.0 wt
%, Mn 0.3 to 0.6 wt%, and further contains one or two of Cu 0.5 wt% or less and Mg 0.5 wt% or less, and the balance is an aluminum alloy ingot composed of Al and unavoidable impurities. When manufacturing fin material by the steps of hot rolling, cold rolling, and annealing, if there is a step of heating to a temperature above 500 ° C, when the temperature reaches 500 ° C or lower of the final step above 500 ° C, In the subsequent steps, if there is no step of heating in the temperature range of 380 to 500 ° C for a total of 4 hours or more and heating to a temperature above 500 ° C, in the step after the homogenization treatment, 380 to 500 ° C. Characterized by heating for a total of 4 hours or more in the temperature range of
A method for producing an aluminum alloy fin material for low temperature brazing, wherein the specific resistance values before and after brazing are 37 nΩm or less. 8. Si0.03-0.8 wt%, Fe0.05-1.0 wt
%, Mn 0.3 to 0.6 wt%, Cr 0.3 wt% or less, Zr 0.3 wt% or less, Ni 0.3 wt% or less, Ti 0.3 wt
% Or less, Mo 0.3wt% or less, Co 0.3wt% or less 1
Aluminum alloy ingot containing at least one of two or more kinds and one or two of Cu 0.5 wt% or less and Mg 0.5 wt% or less and the balance Al and unavoidable impurities is homogenized, hot-rolled, When manufacturing fin material by cold rolling and annealing, if there is a step of heating to a temperature over 500 ° C, when it reaches 500 ° C or less of the last step over 500 ° C, in the subsequent steps. , If you do not have a step of heating in a temperature range of 380 to 500 ° C for a total of 4 hours or more and a temperature of more than 500 ° C, in the temperature range of 380 to 500 ° C in the steps after homogenization treatment. A method for producing an aluminum alloy fin material for low temperature brazing, wherein the specific resistance value before and after brazing is 37 nΩm or less, which is characterized by heating for a total of 4 hours or more.