JP3360026B2 - Brazing method of aluminum alloy brazing sheet for heat exchanger - 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 brazing an aluminum alloy brazing sheet for a heat exchanger, and more particularly to a component of a heat exchanger having a hollow structure such as a laminated heat exchanger (Drone cup type heat exchanger). To a brazing method for brazing aluminum alloy brazing sheets used as radiators, heater cores, and tank materials for capacitors by inert gas atmosphere brazing or vacuum brazing.

[0002]

2. Description of the Related Art Drone cup type aluminum alloy heat exchangers are widely used in evaporators, intercoolers, and air-cooled oil coolers for automobiles. The demand for weight reduction is also increasing. Conventionally, in the above-mentioned drone cup type heat exchanger, in order to reduce the weight, the corrosion resistance of the core material of a three-layer aluminum alloy brazing sheet clad with brazing material on both sides used as a constituent member is improved by improving the corrosion resistance. Has been promoted.

[0003] For example, in a brazing sheet used for a core plate of an evaporator, the content of Fe and Si in a core material made of an Al-Mn alloy is reduced to reduce the Cu content.
It has been proposed to specify the content range of Mg and Mg and to improve the corrosion resistance by adding Ti. It is also proposed to improve the corrosion resistance of the brazing sheet by adding a component such as Zn, In, or Sn to the aluminum alloy brazing material clad in the core material to give a sacrificial anode effect (JP-A-7-55373). Have been. (JP 4
JP-A-9-53146, JP-A-53-30448, JP-A-53-55443, JP-A-53-11
No. 0152)

However, water-cooled oil coolers for automobiles, hydraulic equipment or industrial machines, especially water-cooled oil coolers for automobiles, and other heat exchanger-related members for automobiles through which cooling water flows, are severe under severe operating conditions. Since corrosion is assumed, it is impossible to expect only the improvement of the corrosion resistance of the core material. Means for adding a base element such as Zn, In, or Sn to the brazing material has little effect on brazing materials containing about 7.5 to 10% of Si. Even if the base material is added to lower the natural potential of the brazing material, if the brazing material flows during brazing, the effect as a sacrificial anode layer on the surface layer of the material becomes insufficient.

When Zn is added, part of the Zn diffuses into the core material during the brazing heating, but the cooling after brazing is short, so that the diffusion is not sufficiently performed, and the sacrificial anode is not formed. The effect is not sufficiently obtained. In addition, Zn of the material surface layer portion
The diffusion layer exhibits a sacrificial anode effect against corrosion from the surface layer because the surface layer is base relative to the core material, but when the corrosion reaches the core material and proceeds from the core material to the opposite side. In this case, since the surface layer on the opposite side is more base than the core material, corrosion is promoted and penetrating corrosion occurs. In particular, when the thickness of the brazing sheet is small, it is dangerous to form the sacrificial anode layers on both surface layers from the viewpoint of occurrence of penetration corrosion.

[0006]

SUMMARY OF THE INVENTION The present invention comprises a three-layer aluminum alloy brazing sheet clad with a brazing material on both sides, which is brazed and bonded by inert gas atmosphere brazing or vacuum brazing, and in particular, cooling water. It has been made in order to solve the above-mentioned conventional problems in the heat exchanger member used in contact with, the purpose is,
An object of the present invention is to provide a method for brazing an aluminum alloy brazing sheet for imparting excellent strength and corrosion resistance to a heat exchanger member.

[0007]

According to a first aspect of the present invention, there is provided a method for brazing an aluminum alloy brazing sheet for a heat exchanger, comprising the steps of:
To 1.8%, Cu: 0.05 to 1.2%, Ti: 0.0
2 to 0.3%, Si: 0.01 to 1.0%, Fe: 0.
A core material composed of an aluminum alloy consisting of aluminum and impurities, containing Si: 5 to 15% and Zn: 2.5 to 8.0%. A brazing material composed of an aluminum alloy consisting of the remaining aluminum and impurities is clad, and S
i: Inert gas atmosphere brazing is performed using an aluminum alloy brazing sheet clad with a brazing material containing aluminum alloy containing 5 to 15% and the balance being aluminum and impurities, and cooling after brazing. The process is characterized in that the temperature is maintained in a temperature range of 200 to 550 ° C. for 5 minutes or more. According to a second aspect of the present invention, there is provided a method for brazing an aluminum alloy brazing sheet for a heat exchanger, wherein the aluminum alloy brazing sheet is brazed using an inert gas atmosphere, and the average cooling rate after the brazing is 70 ° C. / Min or less.

[0008] A method of brazing an aluminum alloy brazing sheet for a heat exchanger according to claim 3 is as follows.
To 1.8%, Cu: 0.05 to 1.2%, Ti: 0.0
2 to 0.3%, Si: 0.01 to 1.0%, Fe: 0.
The core material contains 0.6 to 0.8%, and is made of an aluminum alloy containing the balance of aluminum and impurities. One side of the core material has Si: 5 to 15%, Zn: 2.5 to 8.0%, M
g: a brazing material containing 0.3 to 2% and composed of an aluminum alloy containing the balance of aluminum and impurities, and the other surface is Si: 5 to 15% and Mg: 0.3
Vacuum brazing is performed using an aluminum alloy brazing sheet clad with a brazing material containing aluminum alloy containing the balance of aluminum and impurities.
It is characterized in that the temperature is maintained for 5 minutes or more in a temperature range of ５550 ° C. According to a fourth aspect of the present invention, there is provided a method for brazing an aluminum alloy brazing sheet for a heat exchanger, wherein the aluminum alloy brazing sheet is vacuum brazed, and the average cooling rate after the brazing is 70 ° C./min or less. It is characterized by the following.

According to a fifth aspect of the present invention, there is provided a method of brazing an aluminum alloy brazing sheet for a heat exchanger according to the first or second aspect, wherein the brazing material is clad on one surface of the core material and / or the other surface of the core material is clad. The method of brazing an aluminum alloy brazing sheet for a heat exchanger according to claim 6, wherein the Mg content in the brazing material to be produced is 0.04% or less. The brazing material clad on one side of the material further contains In: 0.005 to 0.1%, Sn: 0.0
It is characterized by containing one or two of 1 to 0.2%.

[0010] The method of brazing an aluminum alloy brazing sheet for a heat exchanger according to claim 7 is described in claims 1 to 6.
In any one of the above, the core material further comprises Mg: 0.1 to
It is characterized by containing 0.3%.

The significance of the alloy components in the present invention and the reasons for limiting them will be described. (1) Components of Core Material Mn in the core material functions to improve the strength of the core material, make the potential of the core material noble, increase the potential difference from the sacrificial anode layer, and increase the corrosion resistance. The preferred content range is 0.
5 to 1.8%, and less than 0.5%, the effect is small,
If the content exceeds 1.8%, a coarse compound is formed at the time of casting, which impairs rolling workability, and as a result, it is difficult to obtain a sound plate material.

Cu functions to improve the strength of the core material, make the potential of the core material noble, increase the potential difference with the sacrificial anode layer, and enhance the anticorrosion effect. Further, Cu in the core material diffuses into the brazing material at the time of heating by brazing to form a continuous concentration gradient. As a result, the potential on the core material side becomes noble, the potential on the surface side of the brazing material becomes low, a continuous potential gradient is formed in the brazing material, and the corrosion mode is changed to a laterally extending general corrosion type, and Provides anti-corrosion action against corrosion from water. The preferable content of Cu is in the range of 0.05 to 1.2%. When the content is less than 0.05%, the effect is small, and when it exceeds 1.2%, the corrosion resistance of the core material is lowered, and the melting point is lowered.
At the time of brazing, local melting may occur at the interface with the brazing material, which may become more noble than the natural electrode potential of the core material and promote corrosion.

[0013] Ti is solidified by being divided into a high-concentration region and a low-concentration region, and when they are rolled, they are distributed alternately in a layered manner in the sheet thickness direction. Corrosion is preferentially performed as compared with the prior art, which has the effect of making the form of corrosion into a layer, thereby further improving the corrosion resistance of the core material. Ti
Is preferably in the range of 0.02-0.3%, and 0.02%
If it is less than 0.3%, the effect is small, and if it exceeds 0.3%, a huge compound is liable to be formed at the time of casting, and the rolling workability is impaired.

Si is an Al—Mn—Si-based compound or, when Mg is added, Mg ₂ Si together with Mg.
Has the effect of improving the strength of the core material. Si
The preferred range of content is 0.01 to 1.0%. If the content is less than 0.01%, the effect is not sufficient. If the content exceeds 1.0%, the corrosion resistance is reduced, and the melting point is reduced, so that the local melting at the interface with the brazing at the time of brazing. Is more likely to occur. A more preferred content of Si is in the range of 0.01 to 0.5%.

Fe functions together with Mn to improve the strength of the core material. The preferred content of Fe is 0.06-0.
If it is less than 0.06%, the effect is not sufficient, and if it exceeds 0.8%, the crystal grains become fine and the molten solder tends to erode in the core material, and the high-temperature sag resistance decreases. The more preferable content range of Fe, which increases the self-corrosion property with the addition, is 0.1 to 0.6%. The core material contains, as impurities, 0.3% or less of Zn, 0.3% or less of Cr, 0.3% or less.
The content of the following Zr and 0.1% or less of B does not affect the properties of the core material.

Mg has the effect of forming Mg ₂ Si together with Si and improving the strength of the core material. The preferred content range is 0.1 to 0.3%. If the content exceeds 0.3%, the corrosion resistance is reduced, and in the case of an inert gas atmosphere brazing using a fluoride-based flux, Mg will react with the flux. In addition to the
g of fluoride is generated, and the appearance of the brazed portion becomes poor. In the case of vacuum brazing, the molten braze tends to erode the core material.

(2) Ingredient of brazing material When brazing is performed by brazing in an inert gas atmosphere, the brazing material (A) clad on one surface of the core material is made of Si: 5
-15%, Zn: 2.5-8.0%, aluminum alloy consisting of the balance aluminum and impurities, brazing material (B) clad on the other surface of the core material, Si: 5-15%, The balance is made of an aluminum alloy containing Al and impurities. In the case of vacuum brazing, the brazing material (A) clad on one surface of the core material has Si: 5 to
An aluminum alloy containing 15%, Zn: 2.5 to 8.0% and Mg: 0.3 to 2%, the balance being Al and impurities, the brazing material (B) clad on the other surface of the core material: Si: 5 to Fifteen
%, Mg: 0.3 to 2%, and is composed of an aluminum alloy containing the balance of Al and impurities.

In the components of the brazing filler metals A and B, Si acts to lower the melting point of the aluminum alloy brazing filler metal and increase the fluidity of the molten brazing filler metal. The preferred content of Si is 5 to
In the range of 15%, less than 5%, the effect is small, 15%
%, The melting point sharply increases, and the workability during production decreases. A more preferred content range of Si is
7 to 13%.

Zn, which is a component of the brazing material A, makes the potential of the sacrificial anode layer low, imparts a sacrificial anode effect, and suppresses corrosion of the core material. The preferred content of Zn is in the range of 2.5 to 8.0%. If the content is less than 2.5%, the sacrificial anode effect is not sufficient.
If it exceeds 0%, the effect of lowering the potential is saturated, the anticorrosion effect cannot be increased, and self-corrosion becomes severe. Zn has the effect of diffusing into the core material during brazing and increasing the thickness of the sacrificial anode layer. Even when vacuum brazing is performed, if brazing is performed in a closed space, evaporation of Zn can be suppressed and can remain in the material.

In and Sn added to the brazing material A are Zn
Similarly to the above, the potential of the sacrificial anode layer is made low to give the sacrificial anode effect, thereby suppressing corrosion of the core material. The preferred contents of In and Sn are in the range of 0.005 to 0.1% In: Sn and 0.01 to 0.2%, respectively. The effect is not sufficient below the lower limit, and the effect of lowering the potential is saturated above the upper limit. As a result, the anticorrosion effect cannot be increased and self-corrosion becomes severe.

In the case of vacuum brazing, brazing materials A and B
Mg contained therein breaks an aluminum oxide film and combines with oxygen in the atmosphere to improve brazing properties.
The preferred content of Mg is in the range of 0.3-2%,
If it is less than 2%, the effect is insufficient, and if it exceeds 2%, the melting point of the core material is lowered and the core material is easily melted. Also, the evaporated M
g may adhere to the brazing furnace and ignite.

In brazing using a fluoride flux in an inert gas atmosphere, if Mg is contained, Mg oxide is concentrated on the surface by heat treatment or the like inevitably performed during the brazing sheet manufacturing process. Then, the flux reacts with the flux component, and the flux is consumed until the brazing is melted. Therefore, the content of Mg as an impurity component is preferably limited to 0.04% or less. If the thickness of the brazing material in the brazing sheet is less than 50 μm, Mg in the core material diffuses into the surface layer of the brazing material before the brazing is melted, thereby deteriorating the brazing properties. The effect of the present invention is not impaired even if the brazing materials A and B contain impurities such as Cu of 0.1% or less and Fe, Cr, Zr and Mn of 0.3% or less.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The aluminum alloy brazing sheet for a heat exchanger according to the present invention is obtained by agglomerating an aluminum alloy constituting a core material and a brazing material by, for example, semi-continuous casting, homogenizing the aluminum alloy, and then increasing the thickness to a predetermined thickness. It is manufactured by a process of hot rolling, then combining the materials, forming a clad material by hot rolling according to a conventional method, finally cold rolling to a predetermined thickness, and finally annealing.

In order to use the aluminum alloy brazing sheet of the present invention as a component of a drone cup type heat exchanger, the brazing sheet is press-molded, the brazing material A is laminated on the inside, and both sides are laminated on the outside. Al-Si
A heat exchanger is assembled by brazing and joining an aluminum alloy fin material obtained by cladding a system brazing material. In order to form a tank material such as a radiator or a condenser, a brazing sheet is press-formed into a tank shape, and brazing is performed with the brazing material A surface inside (cooling water side).

In the brazing, an inert gas atmosphere brazing using a fluoride-based flux or vacuum brazing is applied. In order to diffuse Zn in the brazing material A into the core material by brazing heating, in the cooling process after brazing, the temperature is kept at a temperature range of 200 to 550 ° C. for 5 minutes or more, or the average cooling rate after brazing. To 70 ° C./min or less.

By the above-mentioned cooling step, the sacrificial anode effect is effectively exerted even when the brazing material melts and flows during brazing and only a small amount remains on the surface portion of the core material. 200-5
When the holding time at 50 ° C. is less than 5 minutes, and when the average cooling rate exceeds 70 ° C./min, Zn contained in the brazing material
Is not sufficiently diffused into the core material, so that a sufficient sacrificial anode effect cannot be expected.

[0027]

EXAMPLE 1 An aluminum alloy for a core material having a composition shown in Table 1, an aluminum alloy for a brazing material A having a composition shown in Table 2, and an aluminum alloy for a brazing material B having a composition shown in Table 3 by continuous casting. After ingoting the alloy, the alloy for the core material is subjected to a homogenizing treatment, and the alloy for the brazing materials A and B is hot-rolled to a predetermined thickness. Rolling, final annealing to a thickness of 0.4 ~
A soft plate (temper 0) of a 1.4 mm aluminum alloy brazing sheet was produced. Each of the brazing materials A and B clad on both sides of the core material has a thickness of 90 to 100 μm.
m.

With respect to the obtained aluminum alloy brazing sheet, the strength after brazing, corrosion resistance and brazing property were evaluated according to the following methods. Table 4 shows the results. (1) Strength after brazing The brazing sheet was coated with a fluoride-based flux of 5 g /
m ² in a nitrogen gas atmosphere at a brazing temperature of 60
After heating at 5 ° C (material temperature) for 3 minutes, or after heating at 605 ° C (material temperature) of the brazing temperature in vacuum for 3 minutes, cooling was performed under different cooling conditions, and a tensile test was performed to conduct a tensile test. Was measured.

(2) Evaluation of Corrosion Resistance 1 A 5 g / m ² fluoride-based flux was applied to the brazing material B surface of the brazing sheet, and the brazing temperature was set to 605 ° C. (material temperature) for 3 minutes in a nitrogen gas atmosphere. After heating or heating in a vacuum at a brazing temperature of 605 ° C. (material temperature) for 3 minutes and cooling under different cooling conditions,
The test was performed for 1000 hours (according to ASTM G85) to evaluate the corrosion resistance of the brazing material B side.

(3) Evaluation of Corrosion Resistance 2 The surface of the brazing material A
5 g / m^TwoApply and braze in nitrogen gas atmosphere
Heating to 605 ° C (material temperature) for 3 minutes, or
3 minutes at brazing temperature 605 ° C (material temperature) in vacuum
After cooling for various periods and cooling conditions,^-100
ppm, SO_Four ^2-100 ppm, HCO _Three ^-100pp
m, Cu⁺²At 88 ° C in an aqueous solution containing 10 ppm
Heat for 8 hours, then release for 16 hours while cooling to room temperature
By repeating the temperature cycle for three months,
The corrosion resistance on the side of the filler material A was evaluated.

(4) Evaluation of Brazing Property The perforated disk of the brazing sheet was press-formed into the shape shown in FIG. 1 so that the surface A of the brazing material was concave, and the press-formed plate 1 was made into the shape shown in FIG. Laminated as shown, brazing material A,
The surface B is coated with a fluoride-based flux of 5 g / m ² and heated to 605 ° C. (material temperature) in a nitrogen gas atmosphere for 3 minutes, or heated in vacuum at 605 ° C. (material temperature) for 3 minutes. Brazing was performed to produce a brazed molded product 2, and the brazing properties of each part were evaluated.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4] << Table Note >> Cooling conditions Maintained: Time maintained in the temperature range of 550 to 200 ° C in the cooling process (minutes) Brazing properties ○: No melting part and / or defective brazing part observed Brazing method NB ： Inert gas atmosphere brazing VB ： Vacuum brazing

As can be seen from Table 4, all the test materials according to the present invention show excellent tensile strength of 140 MPa or more after brazing, and the maximum corrosion depth in the corrosion test is 0.
It is less than 3 mm and has excellent corrosion resistance. Regarding brazing properties, no local melting was observed, and a good joint was formed.

Comparative Example 1 By continuous casting, an aluminum alloy for a core material having a composition shown in Table 5, an aluminum alloy for a brazing material A having a composition shown in Table 6, and an aluminum alloy for a brazing material B having a composition shown in Table 7 And a soft plate (temper 0) of an aluminum alloy brazing sheet having a thickness of 0.6 to 1.1 mm was prepared according to the same process as in Example 1. The thickness of each of the brazing materials A and B was 90 μm.

Using the obtained brazing sheet as a test material, the tensile strength after brazing was measured in accordance with the method of Example 1, and the corrosion resistance and brazing property were evaluated. Table 8 shows the results. In Tables 5 to 7, the values outside the conditions of the present invention are underlined.

[0039]

[Table 5]

[0040]

[Table 6]

[0041]

[Table 7]

[0042]

[Table 8]

In Table 8, "x" in the evaluation of brazing property means that a poor brazing was recognized, and the melting was a part in which a fused portion was recognized. As shown in Table 8, the test materials out of the conditions of the present invention are inferior in any of the strength after brazing, the corrosion resistance, and the brazing property. Test material No. In No. 8, since the content of Mn was large, a huge compound was generated during casting, and the rollability was hindered, so that a sound plate could not be produced. Test material No. In Nos. 9 and 10, the strength after brazing and heating is low because Mn and Cu of the core material are small. Test material No. 11 and 12 are C of the core material, respectively.
Due to the large amounts of u and Si, the melting point of the core material was lowered, and local melting occurred at the interface between the core material and the brazing material during brazing.

Test material No. 13, 15, and 19 have insufficient strength after brazing because the amounts of Si, Mg, and Fe in the core material are small. Test material No. In No. 14, since the Mg content of the core material was large, the fluoride of Mg was generated, and the fluidity of the brazing was deteriorated, resulting in poor brazing. Test material No. In No. 16, the core material had a large amount of Ti, so a huge compound was produced during casting, which impaired the rollability, and a sound plate could not be produced.
Test material No. In No. 17, since the amount of Ti in the core material is small, the corrosion depth is large on both the inner surface and the outer surface.

Test material No. In No. 18, since the amount of Fe in the core material was large, the corrosion depth was large on both the inner surface and the outer surface, and portions where the wax was eroded into the core material were also observed. Test material No. 2
In the case of No. 0, since the amount of Zn in the brazing material A was large, the brazing was corroded at an early stage, the sacrificial anode effect was not obtained, and deep corrosion occurred in the core material. Test material No. In No. 21, since the amount of Zn in the brazing material A was small, the sacrificial anode effect was not sufficient, and deep corrosion occurred in the core material. Test material No. In No. 22, since the Mg content in the brazing material was large, the fluoride of Mg was generated in the brazing using the fluoride, and the fluidity of the brazing was reduced, resulting in poor brazing. Test material No. In No. 23, the melting point of the core material was lowered due to the large amount of Mg in the brazing materials A and B, and melting occurred. Test material N
o. In Nos. 24 and 25, since the brazing material B contained a base element such as Zn, In, or Sn, corrosion from the brazing material A side was promoted, and penetration corrosion occurred.

[0046]

According to the present invention, there is provided a method for brazing an aluminum alloy brazing sheet for a heat exchanger, which is provided with excellent strength and corrosion resistance after brazing. The brazing method is suitable as a method for brazing and joining an aluminum alloy brazing sheet used as a tank material for a constituent member of a drone cup type heat exchanger, a radiator, a condenser, or the like by inert gas atmosphere brazing or vacuum brazing. Can be used for

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a press-formed plate used for producing a brazed molded product in order to evaluate the brazing property of the aluminum alloy brazing sheet of the present invention.

FIG. 2 is a cross-sectional view showing a brazed product produced by laminating and brazing the press-formed plates of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Press-formed board 2 Brazing molded product

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 1/19 B23K 35/22 C22C 21/00-21/18

Claims (7)

(57) [Claims] 1. Mn: 0.5 to 1.8% (parts by weight, the same applies hereinafter), Cu: 0.05 to 1.2%, Ti: 0.02
~ 0.3%, Si: 0.01 ~ 1.0%, Fe: 0.0
A core material composed of an aluminum alloy containing aluminum and impurities with Si: 5 to 15% and Zn: 2.5 to 8.0%; A brazing material composed of an aluminum alloy consisting of the remaining aluminum and impurities is clad, and S
i: Inert gas atmosphere brazing is performed using an aluminum alloy brazing sheet clad with a brazing material containing aluminum alloy containing 5 to 15% and the balance being aluminum and impurities, and cooling after brazing. A method for brazing an aluminum alloy brazing sheet for a heat exchanger, wherein the brazing sheet is held in a temperature range of 200 to 550 ° C. for 5 minutes or more in the process. 2. An aluminum for a heat exchanger, wherein the aluminum alloy brazing sheet according to claim 1 is brazed in an inert gas atmosphere, and an average cooling rate after the brazing is 70 ° C./min or less. Brazing method for alloy brazing sheet. 3. Mn: 0.5-1.8%, Cu: 0.0
5 to 1.2%, Ti: 0.02 to 0.3%, Si: 0.
01-1.0%, Fe: 0.06-0.8%,
Si: 5 to 15%, Z on one surface of a core material composed of an aluminum alloy containing the remainder aluminum and impurities
n: 2.5 to 8.0%, Mg: 0.3 to 2%,
A brazing material composed of an aluminum alloy consisting of the remainder aluminum and impurities is clad, and Si:
Vacuum brazing is performed using an aluminum alloy brazing sheet clad with a brazing material containing an aluminum alloy containing 5 to 15% and Mg: 0.3 to 2% and the balance being aluminum and impurities. A brazing method for an aluminum alloy brazing sheet for a heat exchanger, wherein the brazing sheet is held in a temperature range of 200 to 550 ° C. for 5 minutes or more in a cooling process after the attachment. 4. An aluminum alloy brazing sheet for a heat exchanger, wherein vacuum brazing is performed using the aluminum alloy brazing sheet according to claim 3, and an average cooling rate after the brazing is 70 ° C./min or less. Brazing method. 5. The Mg content in the brazing material clad on one surface of the core material and / or the brazing material clad on the other surface of the core material is 0.04% or less. The method for brazing an aluminum alloy brazing sheet for a heat exchanger according to claim 1 or 2. 6. The brazing material clad on one surface of the core material further contains: In: 0.005 to 0.1%, Sn: 0.0
The method for brazing an aluminum alloy brazing sheet for a heat exchanger according to any one of claims 1 to 5, wherein the brazing sheet contains one or two of 1 to 0.2%. 7. The core material further contains Mg: 0.1 to 0.3%.
The method for brazing an aluminum alloy brazing sheet for a heat exchanger according to any one of claims 1 to 6, comprising: