JP3345845B2 - Aluminum alloy brazing sheet strip for ERW processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy brazing sheet strip for electric resistance welding, which is subjected to electric resistance processing and used as a tube material for a heat exchanger of an automobile or the like.

[0002]

BACKGROUND OF THE INVENTION Heat exchangers such as radiators
For example, as shown in FIG. 1, a corrugated thin fin 2 is integrally formed between a plurality of flat tubes 1,
Both ends of the flat tube 1 are open to the space formed by the header 3 and the tank 4, and the high-temperature refrigerant is sent from the space on one tank side to the space on the other tank 4 side through the flat tube 1, The heat exchange between the flat tube 1 and the thin fins 2 and the low temperature refrigerant is circulated again.

[0003] As a tube material of such a heat exchanger, for example, a JIS3003 alloy is used as a core material, and the inside of the core material, that is, the side which is always in contact with the refrigerant, is made of JI as a sacrificial material.
S7072 alloy and on the outside of the core, usually JI
A brazing sheet strip clad with a brazing material, such as S4045, is used as a tube material by electric sewing, and is integrally assembled by brazing with other members such as corrugated fins.
As the brazing method, a flux brazing method, a Nocolok brazing method using a non-corrosive flux, or the like is performed, and the brazing is performed by heating to a temperature around 600 ° C.

[0004] In recent years, heat exchangers have been reduced in weight and size, and for that purpose, it has been desired to reduce the thickness of the material. In order to reduce the thickness of the tube material, first, it is necessary to improve the strength by reducing the thickness of the material and ensure the corrosion resistance. On the other hand, several high-strength alloys have been proposed, and a method of improving the strength by adding a large amount of Si or Cu to the core material alloy and a method of improving the strength by adding Mg to the sacrificial material are promising. Have been. However, in recent years, due to such high strength, problems that have not conventionally occurred have arisen as the thickness has been reduced. That is, there is a problem that the tube is cracked during the electric resistance welding.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and as a result of intensive studies, it has been found that the aluminum alloy brazing sheet has excellent strength after brazing and does not cause cracks in the tube at the time of ERW. Article was developed.

That is, the first invention is that Si: 0.5 to 2.5
wt%, Fe: 0.05 to 2.0 wt%, Cu: 0.1 to
An aluminum alloy containing 2.5 wt% and Mn: 0.05 to 2.0 wt%, the balance being Al and inevitable impurities is used as a core material, and Mg: 0.05 to 2.5 wt. %
And Zn: 0.5 to 6.0 wt%, In:
0.002 to 0.3 wt%, Sn: 0.002 to 0.3 wt%
%, Mn: one or two of 0.05 to 1.6 wt%
In a three-layer aluminum alloy brazing sheet strip for electric resistance welding, which is clad as a sacrificial material with an aluminum alloy consisting of a seed and the balance of Al and inevitable impurities, and clad a brazing material made of an aluminum alloy on the other side. A Mg ₂ particle having a particle size of 0.2 μm or more that exists within a range of 5 μm or less from the interface between the sacrificial material and the core material.
An aluminum alloy brazing sheet strip for electric resistance welding, wherein the area occupancy of Si particles is 0.5% or less.

The second invention is characterized in that Si: 0.5 to 2.5
wt%, Fe: 0.05 to 2.0 wt%, Cu: 0.1 to
2.5 wt%, Mn: 0.05 to 2.0 wt%, Mg: 0.05 to 0.5 wt%, Cr: 0.03 to
0.3 wt%, Zr: 0.03-0.3 wt%, Ti: 0.
An aluminum alloy containing at least one of Nitrogen and Al of 0.3 to 0.3 wt% and Ni: 0.03 to 1.5 wt%, the balance being Al and unavoidable impurities. One side contains Mg: 0.05-2.5 wt%.
n: 0.5 to 6.0 wt%, In: 0.002 to 0.3 wt%
%, Sn: 0.002 to 0.3 wt%, Mn: 0.05 to
Contains one or two of 1.6 wt%, with the balance being Al
Aluminum alloy brazing sheet having a three-layer structure for cladding an aluminum alloy composed of aluminum alloy and unavoidable impurities as a sacrificial material and a brazing material composed of an aluminum alloy on the other side. Characterized in that the area occupancy of Mg ₂ Si particles having a size of 0.2 μm or more and having a particle size within a range of 5 μm or less from the interface of the alloy is 0.5% or less. Alloy brazing sheet strip.

In the first and second inventions, the brazing filler metal is 7.0 to 12.0% by weight of Si and 0.1% by weight of Cu.
-8.0 wt%, and Zn: 0.5-6.0 wt%
%, In: 0.002 to 0.3 wt%, Sn: 0.002
It is desirable to use an aluminum alloy containing one or more of 0.3 wt% and the balance of Al and unavoidable impurities.

[0009]

First, the alloy composition of the aluminum alloy brazing sheet strip for electric resistance welding according to the present invention will be described. The core alloy used in the present invention is a high-strength alloy, and is characterized by a large amount of Si added. Among the core alloys, in particular, 1.2
Alloys to which Si is added in an amount of more than wt% and alloys to which Cu is added in an amount of more than 1.2 wt% are alloys that have not been conventionally used for brazing because their melting points are lowered.

The role of each additive element in the core alloy will be described below. Si contributes to strength improvement. If the content of Si is less than 0.5 wt%, the effect of improving the strength is not sufficient, and if it exceeds 2.5 wt%, the melting point is lowered, and even when the brazing alloy of the present invention is used, it melts during brazing. Therefore, Si is 0.5 to
The content is set to 2.5 wt%, and particularly, stable characteristics are exhibited around 1.2 wt%.

[0011] Fe has the effect of distributing coarse intermetallic compounds in the alloy, making the recrystallized grains fine during the intermediate annealing during the manufacturing process of the present invention, and preventing cracking during electric resistance welding.
If the amount is less than 0.05 wt%, the effect is not sufficient, and
If it is added in excess of 0 wt%, the formability will be reduced and the brazing sheet will crack during the electric resistance welding.

Mn is an essential element for distributing a fine intermetallic compound in the alloy and improving the strength without deteriorating the corrosion resistance. If the amount is less than 0.05% by weight, the effect is not sufficient, and if added in excess of 2.0% by weight, the formability is reduced and the brazing sheet is cracked at the time of ERW.

[0013] Cu is present in the alloy in a solid solution state after brazing and improves the strength. When Cu is less than 0.1 wt%, the effect of improving strength is small. An alloy containing more than 1.2 wt% of Cu is an alloy unique to the present invention. If an alloy containing Cu is used as the core material, Cu diffuses into the sacrificial material during brazing, and the sacrificial material has no effect as a sacrificial material, and the corrosion resistance is reduced. Although the amount of Cu in the core material was limited, it could be added in the present invention for the reasons described below. In addition, 1.2
An alloy to which Cu is added in an amount of more than wt% is an alloy that has not been conventionally used because the melting point is lowered. Where C
If the amount of u exceeds 2.5% by weight, the melting point decreases and the brazing alloy of the present invention is melted during brazing. Accordingly, the content of Cu is set to 0.1 to 2.5 wt%,
It shows stable characteristics at ~ 1.5 wt%.

Mg is in a solid solution state and Mg ₂ S in the alloy.
It exists as a fine precipitate phase of i and improves the strength.
If the content is less than 0.05 wt%, there is no effect, and if the content exceeds 0.5 wt%, the flux reacts with Mg when brazing using a non-corrosive flux, so that brazing cannot be performed.

Cr, Zr, and Ti all form a fine intermetallic compound and have a function of improving the strength of the alloy. However, if it is less than 0.03% by weight, there is no effect, and if it is added in more than 0.3% by weight, the formability is reduced, and the brazing sheet is broken at the time of processing such as assembly.

Ni also has the function of forming fine intermetallic compounds and improving the strength of the alloy. However, 0.03wt%
If it is less than 1.5% by weight, the moldability is reduced and the brazing sheet breaks during processing such as assembly.

The components of the core alloy of the present invention have been described above.
Elements other than the above, such as B added for refining the ingot structure, may be contained as long as each is 0.05 wt% or less.

Next, the sacrificial material of the brazing sheet strip of the present invention will be described. Sacrificial material is an important item of the present invention. That is, as a representative of the conventional sacrificial material alloy, JIS 70
There are 72 alloys. However, such a sacrificial material does not have a strength improving effect. Thus, a sacrificial material containing Mg as in the present invention was developed.

The addition of Mg provides a sacrificial effect, increases the strength of the sacrificial material alloy, and improves the strength of the entire material. If the amount is less than 0.05% by weight, there is no effect, and if it exceeds 2.5% by weight, the melting point is lowered and the material is melted during brazing.

The addition of Zn has a sacrificial effect on the alloy.
If the amount is less than 0.5% by weight, the effect is not sufficient, and if the amount exceeds 6.0% by weight, the melting point decreases, and even if the brazing alloy of the present invention is used, it melts during brazing.

The addition of In and Sn also has a sacrificial effect on the alloy. If the amount is less than 0.002% by weight, the effect is not sufficient, and if the amount exceeds 0.3% by weight, the rolling workability of the alloy is reduced, and it is not suitable as a sacrificial material used for a three-layer brazing sheet.

The addition of Mn increases the strength of the sacrificial material alloy and improves the strength of the entire material. If the amount is less than 0.05% by weight, the effect is not sufficient, and if the amount exceeds 1.6% by weight, the rolling workability of the alloy is lowered, and the alloy is not suitable as a sacrificial material used for a three-layer brazing sheet.

The additive elements of the sacrificial alloy according to the present invention are as described above, but Si is 0.5 wt% as an unavoidable impurity.
If it is below, it can be contained, but 0.1 wt% or less is desirable. Fe can be contained if it is 0.8 wt% or less,
0.1 wt% or less is desirable. Cr, Z for strength improvement
Other elements such as r and Ti may be contained as impurity elements as long as each element is 0.05 wt% or less.

Next, the brazing alloy of the present invention will be described. In the present invention, of the alloy composition of the core material, 1.2 wt%
% Of Si and less than 1.2 wt% of Cu, the composition range of 4343 conventionally used as a brazing alloy.
It is possible to use an Al—Si alloy such as an alloy or a 4045 alloy. However, a high-strength core alloy (1.2 wt%
When the above-described core material alloy containing Si or 1.2 wt% or more Cu is used, the brazing alloy according to claim 3 is used. This is because there is a problem that the external corrosion resistance is reduced and a problem that the core material alloy is melted during brazing due to its low melting point. The brazing alloy according to the present invention solves this problem, and exhibits an effect when combined with the core alloy according to the present invention. That is, various studies are made on the external corrosion resistance of the heat exchanger, and when the conventionally used brazing alloy is combined with the high-strength core alloy of the present invention, Cu added to the core alloy is used.
Has been found to diffuse into the brazing material during brazing, to form a low Cu region near the boundary between the brazing material and the core material and to corrode preferentially, thereby causing severe corrosion with swelling. In the present invention, by adding Cu to the brazing alloy, the diffusion of Cu from the core material to the brazing material is prevented, a low Cu region is not generated near the boundary between the brazing material and the core material, and the corrosion resistance is improved. I let it.
It is thought that if the brazing was performed at a temperature of 585 ° C. or less, the melting of the core material alloy would be eliminated, but the brazing temperature was lower than that of the conventional brazing alloy. Has developed a low-alloy alloy.

Next, the role of each element in the brazing alloy and the reasons for its limitation will be described below. Although the addition of Si lowers the melting point of the alloy, if the amount is less than 7.0 wt%, the melting point does not decrease sufficiently, and the core material melts at the brazing temperature. Further, if the amount exceeds 12.0 wt%, the melting point rises conversely, so that the core material is melted.

The addition of Cu lowers the melting point of the alloy and improves the flowability of the solder. Further, when the alloy containing Cu is used for the refrigerant passage constituting member for the above-described reason, the heat exchanger has the function of improving the external corrosion resistance of the heat exchanger. However, when the amount of Cu is 0.1.
If the amount is less than 1 wt%, the above effects are not sufficient, and the amount is 8.
If the content exceeds 0 wt%, the potential of the wax becomes too noble, the core material is preferentially corroded, and the corrosion resistance is reduced.
The rollability of the alloy is reduced, and it cannot be manufactured as a brazing sheet for a heat exchanger. Therefore, Cu is 0.1
と す る 8.0 wt%, but especially 0.5-3.5 wt% shows a stable sacrifice.

The addition of Zn lowers the melting point of the alloy. Further, in the brazing alloy to which Cu is added as in the present invention, although the occurrence of swelling due to external corrosion is suppressed, the potential of the brazing material becomes more noble than the potential of the core material, and the external corrosion proceeds in a pit shape, and the speed is increased. There is a problem that is early. The addition of Zn lowers the potential of the brazing material, brings the potential of the brazing material closer to the potential of the core material, and improves the corrosion resistance. However, the amount is 6.0 wt%
If it exceeds 300, the self-corrosion resistance of the brazing alloy will be reduced, and the rollability of the alloy will be reduced, making it unsuitable as a brazing material for a brazing sheet for a heat exchanger.

In and Sn also lower the potential of the brazing material,
The corrosion resistance of the refrigerant passage component is improved. The amount is 0.
If the amount is less than 002 wt%, the effect is not sufficient, and the amount is 0.3%.
If the content exceeds wt%, the rolling workability of the alloy decreases.

The alloying elements of the brazing material of the present invention are as described above, but Fe can be contained as an unavoidable impurity if the content is 1.0% by weight or less. However, Fe forms intermetallic compounds when the wax solidifies, which is the starting point of corrosion. Therefore, the amount of Fe is desirably 0.5 wt% or less. F
As unavoidable impurities other than e, other elements may be contained if they are each 0.05 wt% or less.

Here, when the brazing material of the present invention is used, it is desirable to perform brazing at a brazing temperature of more than 570 ° C. and 585 ° C. or less. If the brazing temperature is 570 ° C. or lower, there is a composition that does not melt in the brazing material of the present invention, and brazing cannot be performed. On the other hand, if the temperature exceeds 585 ° C., it may melt depending on the composition of the core material. In addition, brazing using the brazing material of the present invention also has the effect of improving the high-temperature buckling resistance and thermal conductivity of the fin.
It should be noted that reducing the brazing temperature in this manner also has the effect of extending the life of the brazing furnace.

As a method of performing brazing at a temperature lower than the normal brazing temperature, there is known a method of performing brazing at a temperature of about 500 ° C., which is called low-temperature brazing. This method has a problem that the brazing material is easily corroded after brazing because the Al-Zn alloy or Zn alloy containing 20% or more of Zn is usually used as a brazing material. not being used. Furthermore, A
If the addition amount of Zn exceeds 1% in an l-Zn alloy, the rollability becomes extremely poor, and it is impossible to produce a brazing sheet by combined rolling, and the brazing sheet for low-temperature brazing is industrially stable. The production method for supplying is not established. For this reason, brazing must be used for placing, etc., and the types of members that can be manufactured are limited. However, the inventors have found that the characteristics of the heat exchanger can be improved even at a brazing temperature of 585 ° C. or lower, which is much higher than the low-temperature brazing as described above, and have developed a brazing sheet.

Further, there is an alloy conventionally known as a low melting point aluminum alloy braze (for example, see Japanese Unexamined Patent Publication No.
-57588). These are developed mainly for brazing castings, and contain a large amount of Cu, or because a large amount of Zn is added as described above, they are broken when subjected to rolling. There was a problem and the brazing sheet could not be manufactured. If it cannot be used as a brazing sheet, it is not practical to manufacture a heat exchanger industrially. The present invention has solved such a problem and developed a brazing sheet.

The above is the alloy composition of the aluminum alloy brazing sheet strip of the present invention. Next, the structure will be described.
The aluminum alloy brazing sheet strip of the present invention is shown in FIG.
Has a three-layer structure as shown in FIG. That is, a high-strength aluminum alloy is used as the core material 5, and the brazing material 6,
The other side has a sacrificial material 7. This is a strip for forming a tube in which the brazing material is on the outside and the sacrificial material is on the side of the refrigerant passage by the electric resistance welding. The thickness of the brazing sheet strip is 0.4
mm or less, the cladding ratio of the sacrificial material is 5 to 30%, and the cladding ratio of the brazing material is 5 to 30%.

This is a feature of the present invention. The area occupation of Mg ₂ Si particles having a particle size of 0.2 μm or more and located within a range of 5 μm or less from the interface between the sacrificial material and the core material. The rate is 0.5% or less. In explaining the reason for this limitation, cracks that occur during the electric resistance machining that has been solved by the present invention will be described. The cracks that have not occurred in the related art have started to occur after a high-strength alloy in which Mg is added to a sacrificial material is used. As shown in FIG. 3, the crack occurred at the interface between the sacrificial material and the core material. The brazing sheet is usually hot-pressed to form a three-layer structure by pressing, but an alloy containing Mg is likely to form an oxide film on its surface, so it is considered that the interface is difficult to join, or a core material alloy and a sacrificial material alloy are used. It is considered that it is not crimped because the deformation resistance with
Various measures were taken. However, such measures did not solve the problem at all.

Therefore, the present inventors have conducted intensive studies, and
When the structure near the interface was examined in detail, it was found, as schematically shown in FIG. 4, that when the Mg ₂ Si particles 11 were present near the interface, cracks occurred during the electric resistance welding. Then, it has been found that if the amount of the Mg ₂ Si particles 11 is equal to or less than a certain value, no crack occurs during the electric resistance welding.
The reason for the generation of the Mg ₂ Si particles 11 is that Mg is diffused from the sacrificial material to the core material during the production of the brazing sheet and reacts with Si contained in the core material. It has been found that Si diffuses into the material and reacts with Mg contained in the sacrificial material to form. That is, it has been clarified that the phenomenon is peculiar to the brazing sheet in which the amount of Si added to the core material is increased to increase the strength, and Mg is added to the sacrificial material.

That is, the essence of the present invention is that the core material contains 0.1% of Si.
A cladding material for high-strength electric resistance welding using an aluminum alloy containing 5 to 2.5 wt% and an aluminum alloy containing 0.05 to 2.5 wt% of Mg as a sacrificial material. The area occupancy of Mg ₂ Si particles having a particle diameter of 0.2 μm or more and having a distance from the interface within 5 μm is 0.5% or less. The reason for the lower limits of Si of the core material and Mg of the sacrificial material is that, in addition to the above-mentioned reason, if the amount is less than this, the above-described cracking does not occur at the time of the electric resistance welding, and the present invention is not required.

Now, the definition of the Mg ₂ Si particles whose distance from the interface between the sacrificial material and the core material is within 5 μm is that the range in which Mg ₂ Si particles are easily generated by diffusion is defined as this range. This is because That is, Mg ₂ Si particles are most likely to be generated at the interface, and the diffusion amount decreases as the distance from the interface decreases, so that the distance from the interface is within 5 μm (5 μm on the sacrificial material side and 10 μm of 5 μm on the core material side). Just think about it. The problem with Mg ₂ Si particles having a particle size of 0.2 μm or more is that if they are smaller than this size, they will form a solid solution during heating during ERW.
This is because it does not affect the crack. Here, to measure the area occupancy, the surface in the thickness direction (L-ST plane or LT-S plane) is used.
T-plane) may be polished, and observation may be performed by lowering the acceleration voltage with a reflected electron image of a scanning electron microscope. The particle size is the maximum diameter.
If the area occupation ratio of the Mg ₂ Si particles exceeds 0.5%, the portion is likely to be melted at the time of electric resistance welding, and cracks occur.
Therefore, Mg _{2 having} a particle size of 0.2 μm or more exists within a range of 5 μm or less from the interface between the sacrificial material and the core material.
In the present invention, the area occupancy of the Si particles is set to 0.5% or less.

As described above, the distribution state of the Mg ₂ Si particles is controlled. The most typical method is a solution treatment and a quenching treatment. That is, since the Mg ₂ Si particles are mainly generated during hot rolling and annealing, the coil after annealing is heated to a temperature equal to or higher than the solution heat treatment temperature, and the Mg ₂ S particles are cooled during cooling.
What is necessary is just to quench rapidly at the speed which does not produce i particles. This solution
Since the quenching treatment is usually higher than the recrystallization temperature, it may be performed also as annealing. In the present invention, the steps after the electric resistance sewing are not particularly limited. The heat exchanger may be manufactured by brazing as conventionally performed.

[0039]

The present invention will be specifically described below with reference to examples. Table 3 shows a three-layer brazing sheet strip having a thickness of 0.25 mm for an aluminum alloy tube material having the structure shown in Table 1.
~ 4. Hot rolled coil (thickness 3.
5 mm) is as usual. Specifically, the core material alloy was water-cooled to a thickness of 400 mm, and then 450 ° C.
After homogenizing in a temperature range of ~ 600 ° C and combining with a brazing alloy plate and a sacrificial alloy plate prepared in advance after facing,
After the heating, hot rolling was performed. Brazing material cladding rate is 13
%, And the cladding ratio of the sacrificial material is 20%. Further, Fe and Si as impurity elements in the sacrificial material are each 0.0%.
It is contained within the range of 1 to 0.2 wt%. The coiled plate was slitted to 35.0 in accordance with the size of the ERW pipe.
mm. A sample was obtained from the obtained strip material, the structure of the cross section was observed, and Mg ₂ Si particles having a size of 0.2 μm or more and having a distance from the interface between the core material and the sacrificial material within 5 μm were measured. Tables 5 and 6 show the results of measuring the area occupancy. Further, the obtained strip was subjected to electric resistance welding, and a pressure test and a cross-sectional observation were performed on the obtained tube. Further, the obtained strip was heated in N ₂ gas, and a tensile test and an external corrosion resistance test were performed with the brazing material part outside and the sacrificial material part inside. The results are shown in Tables 5 and 6. The additional heat of the brazing is the brazing sheet strips A, E,
F, G, I, J, and K were set at 580 ° C. × 5 minutes, and the other brazing sheet strips were set at 600 ° C. × 5 minutes. In the external corrosion resistance test, only the central part of the surface of the brazing material was exposed, all the other surfaces were sealed, and the CASS test (JISH8681) was performed according to 360.
It was carried out for a while, and the occurrence of pitting was examined.

[0040]

[Table 1]

[0041]

[Table 2]

[0042]

[Table 3]

[0043]

[Table 4]

[0044]

[Table 5]

[0045]

[Table 6]

Comparative Example No. In Nos. 18 to 28, the brazing sheet strip is a composition of the present invention. However, since the brazing sheet strip is manufactured by a conventional process, the amount of Mg ₂ Si is out of the range of the present invention, cracks are generated by electric resistance welding, and the pressure resistance value is Low. Comparative Example No. 29,
No. 30 is out of the range of the amount of Si of the core material or the amount of Mg of the sacrificial material of the present invention, and does not crack by the electric resistance welding, but has low strength after brazing. Also, the conventional example No. 31 does not crack by the electric resistance welding, but has a low strength after brazing. On the other hand, in the example of the present invention, despite the high strength after brazing and the excellent corrosion resistance, no crack is generated by the electric resistance welding.

[0047]

As described above, the aluminum alloy brazing sheet strip for ERW processing of the present invention does not crack during ERW processing, has high strength and is excellent in corrosion resistance, and is small in size when a heat exchanger is manufactured. It is possible to reduce the weight, and has a remarkable industrial effect.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional perspective view showing a radiator.

FIG. 2 is a sectional view showing the structure of the brazing sheet strip of the present invention.

FIG. 3 is a partial cross-sectional view of an electric resistance welded pipe showing a state of occurrence of cracks during electric resistance welding.

FIG. 4 is a schematic diagram showing a situation at an interface between a core material of a brazing sheet strip and a sacrificial material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Flat tube 2 Thin fin 3 Header 4 Tank 5 Core material 6 Brazing material 7 Sacrificial material 8 Interface between core material and sacrificial material 9 ERW welded part 10 Crack 11 Mg ₂ Si particles

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

Claims (3)

(57) [Claims] (1) Si: 0.5 to 2.5 wt%, Fe: 0.
05 to 2.0 wt%, Cu: 0.1 to 2.5 wt%, Mn:
An aluminum alloy containing 0.05 to 2.0 wt%, the balance being Al and unavoidable impurities is used as a core material, and one side of the core material contains 0.05 to 2.5 wt% of Mg:
n: 0.5 to 6.0 wt%, In: 0.002 to 0.3 wt%
%, Sn: 0.002 to 0.3 wt%, Mn: 0.05 to
Contains one or two of 1.6 wt%, with the balance being Al
Aluminum alloy brazing sheet having a three-layer structure for cladding an aluminum alloy composed of aluminum alloy and unavoidable impurities as a sacrificial material and a brazing material composed of an aluminum alloy on the other side. Characterized in that the area occupancy of Mg ₂ Si particles having a size of 0.2 μm or more and having a particle size within a range of 5 μm or less from the interface of the alloy is 0.5% or less. Alloy brazing sheet strip. 2. Si: 0.5 to 2.5 wt%, Fe: 0.
05 to 2.0 wt%, Cu: 0.1 to 2.5 wt%, Mn:
0.05-2.0 wt%, and further Mg: 0.05
-0.5 wt%, Cr: 0.03-0.3 wt%, Zr:
0.03-0.3 wt%, Ti: 0.03-0.3 wt%,
Ni: an aluminum alloy containing one or more of 0.03 to 1.5 wt%, the balance being Al and unavoidable impurities is used as a core material, and Mg: 0.0
5 to 2.5 wt%, and Zn: 0.5 to 6.0.
wt%, In: 0.002 to 0.3 wt%, Sn: 0.00
2 to 0.3 wt%, Mn: one or two of 0.05 to 1.6 wt%, clad as an sacrifice aluminum alloy consisting of the balance of Al and inevitable impurities,
In the aluminum alloy brazing sheet for electric resistance welding having a three-layer structure in which a brazing material made of an aluminum alloy is clad on one other surface, a particle size of 0 having a distance from the interface between the sacrificial material and the core material within 5 μm or less. An aluminum alloy brazing sheet strip for electric resistance machining, wherein an area occupation ratio of Mg ₂ Si particles having a size of ₂ μm or more is 0.5% or less. 3. A brazing material comprising: Si: 7.0 to 12.0 wt%;
Cu: 0.1 to 8.0 wt%, and Zn: 0.
5 to 6.0 wt%, In: 0.002 to 0.3 wt%, S
3. An aluminum alloy according to claim 1, wherein said aluminum alloy contains one or more of 0.002 to 0.3 wt%, and the balance is Al and inevitable impurities. Aluminum alloy brazing sheet for sewing.