JP2011241439A - Aluminum alloy brazing sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy brazing sheet for a heat exchanger excelling in strength after brazing and corrosion resistance, and also excelling in electric resistance weldability.SOLUTION: This aluminum alloy brazing sheet includes: a core material containing Si, Cu and Mn by a predetermined amount, wherein the remnant comprises Al and inevitable impurities; a sacrificial material disposed on one face side of the core material and containing Si, Zn and Mg by a predetermined amount, wherein the remnant comprises Al and inevitable impurities; and a brazing material disposed on the other face side of the core material and formed of an aluminum alloy. In the aluminum alloy brazing sheet, the area occupancy of Zn-Mg-based intermetallic compounds each having a particle size ≥2.0 μm on the surface of the sacrificial material is ≤1.0%.

Description

  The present invention relates to an aluminum alloy brazing sheet used in a heat exchanger such as an automobile.

  In general, various aluminum alloy brazing sheets (hereinafter sometimes simply referred to as “brazing sheets”) in which a brazing material and a sacrificial material are disposed on one or both sides of a core material are used as materials for heat exchangers of automobiles and the like. Yes. Conventionally, Al-Mn 3003 aluminum alloy has been used as the core material of this brazing sheet, but the brazing sheet using this core material has not been sufficient in strength and corrosion resistance after brazing.

Therefore, techniques for improving the strength and corrosion resistance of brazing sheets after brazing have been proposed. For example, there is a technique for improving the strength after brazing without adding a predetermined amount of Mg to the sacrificial material of the brazing sheet (for example, Patent Document 1). More specifically, this technique is based on the fact that Mg added to the sacrificial material and Si present in the brazing material diffuse into the core material when the brazing heat is applied to generate Mg ₂ Si inside the core material, thereby brazing the brazing sheet. While improving the strength after brazing, Mg added to the sacrificial material does not reach the brazing material, thereby avoiding a decrease in brazing performance.

  Moreover, while adding a predetermined amount of Cu to the core material of the brazing sheet and adding a predetermined amount of Zn to the sacrificial material, the sacrificial material has a predetermined thickness, thereby improving the strength and corrosion resistance of the brazing sheet after brazing. (For example, Patent Document 2). Specifically, in this technique, the corrosion resistance is improved by setting Zn and the sacrificial material added to the sacrificial material to a predetermined thickness, and the strength after brazing is improved by solid solution strengthening with Cu added to the core material.

Japanese Patent No. 2564190 (see right column on page 2) Japanese Patent No. 3276790 (see paragraph 0013)

  However, recent demands for heat exchangers such as automobiles have not only improved the strength and corrosion resistance after brazing, but also reduced the size and weight. In order to meet this demand for miniaturization and weight reduction, it is necessary to reduce the thickness of the heat exchanger material. However, the thinner the heat exchanger material, the lower the strength and corrosion resistance. . In addition, the thinning of the material of the heat exchanger becomes a factor that causes a welding defect during electric sewing.

  This invention is made | formed in view of this point, Comprising: While being excellent in the intensity | strength after brazing and corrosion resistance, it is providing the aluminum alloy brazing sheet for heat exchangers which was excellent also in electro-weldability.

  This inventor repeated earnest experiment and examination about the factor which improves the electro-weldability of a brazing sheet. And the area occupation rate of the Zn-Mg intermetallic compound of the sacrificial material of the brazing sheet is correlated with the electro-weldability of the brazing sheet, and the area occupation rate of the Zn-Mg intermetallic compound is reduced. It has been found that the electro-weldability of the brazing sheet is improved.

  That is, in order to solve the above-described problems, the aluminum alloy brazing sheet according to the present invention has Si: 0.1 to 1.0% by mass, Cu: 0.5 to 1.2% by mass, Mn: 0.5 to 2.0% by mass, with the balance being made of Al and inevitable impurities, and disposed on one side of the core material, Si: more than 0.2% by mass and 0.8% by mass or less, Zn: 3. 0% by mass to 5.0% by mass or less, Mg: 1.0 to 4.5% by mass, the rest being a sacrificial material composed of Al and inevitable impurities, and disposed on the other surface side of the core material, An aluminum alloy brazing sheet comprising a brazing material made of an aluminum alloy, wherein an area occupation ratio of a Zn-Mg intermetallic compound having a particle size of 2.0 µm or more on the surface of the sacrificial material is 1.0% or less. It is characterized by that. The core material further contains at least one selected from Ti: 0.05 to 0.25% by mass, Cr: 0.25% by mass or less, and Mg: 0.5% by mass or less. To do.

  With such a configuration, the aluminum alloy brazing sheet can improve strength after brazing, brazing, and corrosion resistance by setting the core material and the sacrificial material to a predetermined composition. Further, by limiting the number density of the Zn—Mg-based intermetallic compound on the surface of the sacrificial material, it is possible to stabilize melting at the time of electro-sewing.

  According to the aluminum alloy brazing sheet for a heat exchanger according to the present invention, by improving the strength after brazing, the brazing property, and the corrosion resistance, by stabilizing the melting at the time of ERW processing, Can be improved.

Hereinafter, the aluminum alloy brazing sheet according to the embodiment will be described in detail.
≪Aluminum alloy brazing sheet≫
An aluminum alloy brazing sheet is a plate material used for heat exchangers of automobiles, etc., and is composed of a core material, a sacrificial material crimped to one side surface of the core material, and a brazing material crimped to the other side surface of the core material. .
Hereinafter, the core material, the sacrificial material, and the brazing material will be described.

≪Heart material≫
The core material contains Si: 0.1 to 1.0% by mass, Cu: 0.5 to 1.2% by mass, Mn: 0.5 to 2.0% by mass, and the balance from Al and inevitable impurities Become.
And in addition to the said component (Si, Cu, Mn), a core material is selected from Ti: 0.05-0.25 mass%, Cr: 0.25 mass% or less, Mg: 0.5 mass% or less. It is preferable to further contain at least one kind.

<Si of core material: 0.1 to 1.0% by mass>
Si forms an intermetallic compound together with Al and Mn, and is finely distributed within the crystal grains, contributing to dispersion strengthening and improving strength.
If the Si content is less than 0.1% by mass, the strength after brazing decreases. On the other hand, if the Si content exceeds 1.0% by mass, the solidus temperature of the core material is lowered, so that the core material is melted during brazing addition heat. Therefore, the amount of Si contained in the core is within the above range.

<Cu of core material: 0.5 to 1.2% by mass>
Cu has the effect of improving the strength after brazing, and the addition of Cu makes the potential noble and increases the potential difference from the sacrificial material, thereby improving the corrosion resistance.
If the Cu content is less than 0.5% by mass, the strength after brazing decreases, and the potential difference from the sacrificial material cannot be ensured, and the internal corrosion resistance decreases. On the other hand, when the Cu content exceeds 1.2% by mass, the solidus temperature of the core material is lowered, so that the core material is melted at the time of brazing addition heat. Therefore, the amount of Cu contained in the core is within the above range.

<Mn of core material: 0.5 to 2.0 mass%>
Mn has the effect of improving the strength after brazing.
When the content of Mn is less than 0.5% by mass, the number of intermetallic compounds formed with Al and Si decreases, and the strength after brazing decreases. On the other hand, if the content of Mn exceeds 2.0% by mass, a coarse intermetallic compound is formed at the time of casting, and workability and corrosion resistance are lowered. Therefore, the amount of Mn contained in the core is within the above range.

<Ti of core material: 0.05 to 0.25% by mass>
Ti is distributed in layers in the core material and greatly improves the corrosion resistance of the inner and outer surfaces.
If the Ti content is less than 0.05% by mass, the corrosion resistance cannot be sufficiently improved. On the other hand, if the Ti content exceeds 0.25% by mass, a coarse intermetallic compound is formed during casting, and workability and corrosion resistance deteriorate. Therefore, the amount of Ti contained in the core is within the above range.

<Cr of core material: 0.25 mass% or less>
Cr has an effect of forming an intermetallic compound in the core material and improving the strength after brazing.
If the Cr content exceeds 0.25 mass%, a coarse intermetallic compound is formed during casting, and workability and corrosion resistance are reduced. Therefore, the amount of Cr contained in the core is within the above range.

<Mg of core material: 0.5 mass% or less>
Mg forms a fine precipitated phase of Mg ₂ Si together with Si and improves the strength.
If the Mg content exceeds 0.5 mass%, the flux and Mg react when brazing using a non-corrosive flux, and brazing cannot be performed. Therefore, the amount of Mg contained in the core is within the above range.

<The remainder of the core material: Al and inevitable impurities>
In addition to the above, the remainder of the core material consists of Al and inevitable impurities. Inevitable impurities include, for example, Fe, Zr, and the like, and these are each allowed to be contained in the core material without impeding the effects of the present invention as long as the content is 0.2% by mass or less. Is done.

≪Sacrificial material≫
A sacrificial material is arrange | positioned at the one surface side of a core material, Si: more than 0.2 mass% and 0.8 mass% or less, Zn: more than 2.0 mass% and 5.0 mass% or less, Mg: 1.0- It contains 4.5 mass%, and the balance consists of Al and inevitable impurities. Moreover, the area occupation rate of the Zn—Mg-based intermetallic compound having a particle size of 2.0 μm or more on the surface of the sacrificial material is 1.0% or less.

<Sacrificial material Si: more than 0.2% by mass and 0.8% by mass or less>
Si forms a fine precipitated phase of Mg ₂ Si together with Mg and improves the strength.
When the Si content is 0.2% by mass or less, the effect of precipitating Mg ₂ Si is small. On the other hand, when the Si content exceeds 0.8% by mass, the solidus temperature of the sacrificial material is lowered and melts at the time of brazing addition heat. Therefore, the amount of Si contained in the sacrificial material is within the above range.

<Zinc of sacrificial material: more than 3.0% by mass and 5.0% by mass or less>
Zn is an element that lowers the potential, and when added to the sacrificial material, it has the effect of ensuring the potential difference from the core material and improving the internal corrosion resistance.
When the Zn content is 3.0% by mass or less, the potential difference from the core material becomes small, and the inner surface corrosion resistance decreases. On the other hand, when the Zn content exceeds 5.0% by mass, the solidus temperature of the sacrificial material is lowered and melts at the time of brazing addition heat. Therefore, the amount of Zn contained in the sacrificial material is within the above range.

<Sacrificial material Mg: 1.0 to 4.5% by mass>
Mg forms a fine precipitated phase of Mg ₂ Si together with Si and improves the strength.
If the Mg content is less than 1.0% by mass, the effect of precipitating Mg ₂ Si is small, and the strength is not sufficiently improved. On the other hand, when the Mg content exceeds 4.5% by mass, the clad pressure-bonding property is lowered, and it becomes difficult to laminate the side material on the core material. Therefore, the amount of Mg contained in the sacrificial material is within the above range.

<The remainder of the sacrificial material: Al and inevitable impurities>
In addition to the above-mentioned components of the sacrificial material, the balance consists of Al and inevitable impurities. Inevitable impurities include, for example, Mn, Cr, Zr, Fe, In, Sn, etc., Mn is less than 0.05% by mass, Cr and Zr are each 0.2% by mass or less, and Fe is 0%. .25% by mass or less, and In and Sn each having a content of 0.1% by mass or less are allowed to be contained in the sacrificial material without impeding the effects of the present invention.

<Area occupation ratio of Zn—Mg intermetallic compound on sacrificial material surface>
By making the area occupancy of the Zn-Mg-based intermetallic compound with a particle size of 2.0 μm or more 1.0% or less, it is possible to stabilize the melting at the time of the electro-sewing process, and as a result, it is possible to weld well. Can be done. On the other hand, when the area occupancy ratio of the Zn—Mg intermetallic compound having a particle size of 2.0 μm or more exceeds 1.0%, the portion where the Zn—Mg intermetallic compound exists is locally excessively melted during electro-sewing processing. However, the state of butt becomes unstable and welding defects are likely to occur. Note that a Zn—Mg intermetallic compound having a particle size of less than 2.0 μm has little effect on poor welding.
Here, the particle diameter is the maximum diameter. The sacrificial material surface is a surface on the side different from the side on which the core material is disposed.

  Thus, in order to make the area occupancy of Zn-Mg intermetallic compound having a particle size of 2.0 μm or more present on the surface of the sacrificial material 1.0% or less, and to ensure the formability during ERW welding. It is necessary to control the conditions of finish annealing performed after the final cold rolling. Details of the conditions will be described later.

  In addition, the area occupation rate of a Zn-Mg type | system | group intermetallic compound can be measured by grind | polishing a sacrificial material surface and observing with a scanning electron microscope, for example. However, a scanning electron microscope cannot distinguish between an Fe-based intermetallic compound and a Zn—Mg-based intermetallic compound contained at an impurity level. Therefore, the property that almost all of the Zn—Mg-based intermetallic compound is produced by finish annealing after the final cold rolling, and the Fe-based intermetallic compound is in the intermediate annealing and the final annealing after the final cold rolling. Using the property of not changing, the material before finish annealing and the material after finish annealing were each observed with a scanning electron microscope. And by calculating | requiring the difference of the area occupation rate of Fe type | system | group and Zn-Mg type intermetallic compound after finishing annealing, and the Fe type intermetallic compound area rate before finishing annealing, the area of only Zn-Mg type intermetallic compound Occupancy rate can be determined.

≪Brazing material≫
The brazing material is disposed on the other side of the core material and is made of an aluminum alloy. Examples of the aluminum alloy include general JIS alloys such as 4343 and 4045. The aluminum alloy includes an alloy containing Zn in addition to an alloy containing Si. That is, examples of the aluminum alloy include an Al—Si based alloy and an Al—Si—Zn based alloy. And, for example, an Al—Si based alloy containing Si: 7 to 12% by mass can be used.

When the Si content is less than 7% by mass, the amount of Al—Si liquid phase at the brazing temperature is small, and the brazing property tends to be inferior. On the other hand, when the content exceeds 12% by mass, coarse primary crystal Si increases during casting of the brazing material, so that excessive melting of the core material and the brazing material sea surface during the production of the brazing sheet is likely to occur, reducing the strength and corrosion resistance after brazing. Cheap.
However, the brazing material is not particularly limited, and any brazing material may be used as long as it is a commonly used Al (Al—Si, Al—Si—Zn) alloy. It is also possible to use Al-Si-Mg-based and Al-Si-Mg-Bi-based alloys used for vacuum brazing. Further, in addition to Si, Zn, Mg, Bi, Fe, Cu, Mn, and the like may be contained.

Next, the manufacturing method of the aluminum alloy brazing sheet which concerns on embodiment is demonstrated.
≪Method for producing aluminum alloy brazing sheet≫
First, a core material, a sacrificial material, and a brazing material, which are materials of the aluminum alloy brazing sheet, are manufactured. The manufacturing method of the core material, the sacrificial material, and the brazing material is not particularly limited. For example, the core material can be manufactured by casting the aluminum alloy for the core material having the above composition at a predetermined casting temperature, then chamfering the obtained ingot to a desired thickness and performing a homogenization heat treatment. Further, after casting the sacrificial material aluminum alloy and the brazing material aluminum alloy having the above composition at a predetermined casting temperature, the obtained ingot is chamfered to a desired thickness and subjected to a homogenization heat treatment. And a sacrificial material and a brazing material can be manufactured by hot rolling to a predetermined plate thickness.

  Thereafter, a sacrificial material is stacked on one side surface of the core material, a brazing material is stacked on the other side surface, and each is crimped by hot rolling to form a plate material. And an aluminum alloy brazing sheet is manufactured by performing cold rolling, intermediate annealing, final cold rolling, and finish annealing with respect to the said board | plate material.

<About the conditions of finish annealing>
About the said finish annealing, it is necessary to perform on the conditions that processing temperature is 250 degreeC or more and 500 degrees C or less, holding time is 10 hours or less, and the subsequent cooling rate is 5 degrees C / min or more. By performing the finish annealing under the above conditions, the area occupancy of the Zn—Mg-based intermetallic compound having a particle size of 2.0 μm or more present on the surface of the sacrificial material as described above can be set to 1.0% or less.
If the temperature of finish annealing is less than 250 degreeC, the effect which relieve | moderates the processing distortion at the time of rolling as annealing treatment will not be acquired, but it will also worsen about a moldability. Moreover, when the temperature of finish annealing exceeds 500 degreeC or the time of finish annealing exceeds 10 hours, the Zn-Mg type intermetallic compound grows coarsely, and the intermetallic compound having a particle size of 2.0 μm or more The area ratio exceeds 1.0%. In addition, high-temperature, long-time heat treatment not only promotes diffusion and adversely affects other properties, but also hinders productivity. From the viewpoint of securing overall material properties, 450 ° C. or less, 10 hours The following is preferred. About processing temperature, More preferably, it is the range of 310 to 450 degreeC. If the cooling rate is less than 5 ° C./min, the Zn—Mg intermetallic compound becomes coarse in the cooling process, and the area occupation ratio of the metal compound having a particle size of 2.0 μm or more exceeds 1.0%. .

  Next, the aluminum alloy brazing sheet according to the present invention will be specifically described by comparing an example satisfying the requirements of the present invention with a comparative example not satisfying the requirements of the present invention.

<Manufacture of core material>
S1 to S23 core alloy for core material having the composition shown in Table 1 was ingoted by a continuous casting method, and subjected to chamfering and homogenization treatment as necessary to obtain a core material ingot.

<Manufacture of sacrificial materials>
G1 to G13 sacrificial anode material aluminum alloys having the composition shown in Table 2 are agglomerated by a continuous casting method, subjected to face milling and homogenization as necessary, and hot-rolled to a predetermined plate thickness, It was set as the board | plate material for sacrificial materials.

<Manufacturing for brazing material>
An aluminum alloy for brazing filler metals R1 to R3 having the composition shown in Table 3 is agglomerated by a continuous casting method, subjected to face grinding and homogenization treatment as necessary, and hot-rolled to a predetermined plate thickness. It was made into the board material for.

<Manufacture of aluminum alloy brazing sheet>
The sacrificial material plate material of any one of G1 to G13 is superposed on one side surface of any of the manufactured S1 to S23 materials so that the clad rate is 15%. On the other side, one of the brazing material plates among R1 to 3 was superposed so that the clad rate was 15%, and pressed by hot rolling to obtain a plate material. Then, cold rolling, intermediate annealing, final cold rolling, and finish annealing were performed on the plate material to obtain a plate material with a plate thickness of 0.25 mm.
The finish annealing was performed under the conditions described in Tables 4 and 5.

Next, using the aluminum alloy brazing sheet prepared by the above method as a test material, the area occupancy [%] of the Zn—Mg intermetallic compound of the test material, electro-weldability, strength after brazing, brazing The properties and corrosion resistance were measured and evaluated by the methods described later, and the results are shown in Tables 4 and 5.
In Tables 4 and 5, those that could not be measured / evaluated and those that were not measured / evaluated are indicated by “−”.

  And in this example, all of these evaluation items are evaluated as good examples satisfying the requirements of the present invention, and one of these evaluation items is evaluated as defective. It was set as the comparative example which does not satisfy | fill requirements.

<Area occupation ratio of Zn-Mg intermetallic compound>
The area occupation ratio of the Zn—Mg-based intermetallic compound was measured by polishing the surface of the sacrificial material and observing it with a scanning electron microscope. Specifically, the specimen before finish annealing and the specimen after finish annealing were observed with a scanning electron microscope. And by calculating | requiring the difference of the area occupation rate of Fe type | system | group and Zn-Mg type intermetallic compound after finishing annealing, and the Fe type intermetallic compound area rate before finishing annealing, the area of only Zn-Mg type intermetallic compound Occupancy rate was determined.
The area occupancy is “(total area of Zn—Mg intermetallic compound having a particle size of 2.0 μm or more at the observation location / total observation area) × 100”.

<Electric seam weldability evaluation>
The aluminum alloy brazing sheet produced by the above method was subjected to slit processing using a normal slitter device so that the width of the strip was 35 mm to obtain a winding coil shape. The strip obtained in this way was processed into an electric resistance pipe by an electric resistance pipe manufacturing apparatus to obtain a flat pipe having a major axis of 16 mm and a minor axis of 2 mm.
For the electric resistance weldability evaluation, the appearance of the obtained electric resistance welded pipe was inspected for 100 m, and the presence or absence of an unwelded portion of 5 mm or more in the longitudinal direction was observed.
When there was no unwelded part of 5 mm or more, the weldability was evaluated as good (◯). On the other hand, the weldability was evaluated as poor (x) when there were one or more unwelded portions of 5 mm or more.

<Evaluation of strength after brazing>
After brazing the test material by the drop test method (after heating for 5 minutes at a temperature of 600 ° C. in a nitrogen atmosphere with a dew point of −40 ° C. and an oxygen concentration of 200 ppm or less), it is processed into a JIS No. 5 test piece (each sample) Three pieces were prepared for each sample. The test piece was left at room temperature (25 ° C.) for 1 week, and then the strength after brazing was measured by a tensile test. Three specimens having an average strength after brazing of 170 MPa or more were evaluated as good (◯), and those less than 170 MPa were evaluated as defective (×).
The evaluation of the strength after brazing was carried out only for those having good evaluation of ERW weldability.

<Evaluation of brazing>
A test piece having a size of 25 mm width × 60 mm length was cut out from the test material, and 5 g / m ² of non-corrosive flux FL-7 (manufactured by Morita Chemical Co., Ltd.) was applied to the brazing material surface of the test piece. Dried.
A test piece is placed so that the brazing filler metal surface coated with the flux faces upward, and a φ2 mm stainless steel round bar is sandwiched as a spacer, and a 3003 alloy plate having a thickness of 1 mm, a width of 25 mm and a length of 55 mm is obtained. The test piece was fixed vertically with a wire. At this time, the position of the spacer was set to a distance of 50 mm from one end of the test piece. On the other hand, brazing (heating at 600 ° C. for 5 minutes in a nitrogen atmosphere with a dew point of −40 ° C. and an oxygen concentration of 200 ppm or less) was performed.
The length of the fillet filled in the gap between the test piece and the 3003 alloy plate is measured, and when the fillet length is 30 mm or more, the brazeability is evaluated as good (◯), and the fillet length is less than 30 mm The brazing property was evaluated as poor (×).
The evaluation of brazing was carried out only for those having good evaluations of electric resistance weldability and strength after brazing.

<Evaluation of corrosion resistance>
After brazing the test material by the drop test method (after heating for 5 minutes at a temperature of 600 ° C. in a nitrogen atmosphere with a dew point of −40 ° C. and an oxygen concentration of 200 ppm or less), the size is 50 mm wide × 60 mm long Disconnected. Furthermore, the masking seal 60 mm wide x 70 mm long is used to cover the brazing material surface with the entire seal, and the seal is folded back to the sacrificial material surface side to seal the 5 mm portion from each side of the sacrificial material. A test specimen was prepared.
This test piece was immersed in a test solution containing Na ⁺ : 118 ppm, Cl ⁻ : 58 ppm, SO ₄ ²⁻ : 60 ppm, Cu ²⁺ : 1 ppm, Fe ³⁺ : 30 ppm (88 ° C. × 8 hours), and after immersion, it was allowed to reach room temperature. After natural cooling, a corrosion resistance test was performed in which 90 cycles of holding at room temperature for 16 hours were performed.
The corrosion state was visually observed, and those having a maximum corrosion depth of 50 μm or less were evaluated as good (◯), and those having a maximum corrosion depth exceeding 50 μm were judged as defective (×).
The corrosion resistance was evaluated only for those having good evaluations of electric resistance weldability, strength after brazing, and brazing.

  As shown in Table 4, Example No. Since the brazing sheets of 1 to 20 satisfy the requirements of the present invention, the electro-sealing weldability, the strength after brazing, the brazing property, and the corrosion resistance were evaluated as favorable. On the other hand, as shown in Table 5, Comparative Example No. Since the brazing sheets of 1 to 20 do not satisfy any of the requirements defined by the present invention, the evaluation was not good.

  Specifically, Comparative Example No. In the brazing sheets 1 to 3, the area occupation ratio of the Zn—Mg intermetallic compound having a particle diameter of 2.0 μm or more on the surface of the sacrificial material exceeded 1.0%. This resulted in poor weldability.

  Comparative Example No. The brazing sheet of No. 4 had a low strength after brazing because Si in the core material was less than 0.1% by mass. Comparative Example No. In the brazing sheet of No. 5, since Si in the core material exceeded 1.0% by mass, the core material melted during brazing addition heat, and the strength after brazing could not be measured.

  Comparative Example No. The brazing sheet of No. 6 had low strength after brazing because Cu in the core material was less than 0.5% by mass. Comparative Example No. In the brazing sheet of No. 7, since Cu in the core material exceeded 1.2 mass%, the core material melted during brazing addition heat, and the strength after brazing could not be measured.

  Comparative Example No. The brazing sheet of No. 8 had a low strength after brazing because Mn in the core material was less than 0.5% by mass. Comparative Example No. The brazing sheet of No. 9 resulted in poor corrosion resistance because Mn in the core material exceeded 2.0 mass%.

  Comparative Example No. The brazing sheet of No. 10 resulted in poor corrosion resistance because Cr in the core material exceeded 0.25% by mass.

  Comparative Example No. Since the brazing sheet of No. 11 had a Ti content of less than 0.05% by mass, the corrosion resistance was poor. Comparative Example No. No. 12 brazing sheet had poor corrosion resistance because Ti in the core material exceeded 0.25% by mass.

  Comparative Example No. The brazing sheet of No. 13 resulted in poor brazeability because Mg in the core material exceeded 0.5% by mass.

  Comparative Example No. No. 14 brazing sheet had low strength after brazing because Si in the sacrificial material was 0.2 mass% or less. Comparative Example No. In the brazing sheet of No. 15, since the Si in the sacrificial material exceeded 0.8% by mass, the sacrificial material melted during brazing addition heat, and the strength after brazing could not be measured.

  Comparative Example No. The brazing sheet No. 16 had poor corrosion resistance because Zn in the sacrificial material was less than 3.0% by mass. Comparative Example No. In the brazing sheet of No. 17, the Zn in the sacrificial material exceeded 5.0% by mass, so the sacrificial material melted during brazing addition heat, and the strength after brazing could not be measured.

  Comparative Example No. The brazing sheet of 18 had low strength after brazing because Mg in the sacrificial material was less than 1.0% by mass. Comparative Example No. In No. 19 brazing sheet, Mg in the sacrificial material exceeded 4.5% by mass, so the side material could not be laminated on the core material, and the test could not be performed.

  Comparative Example No. In the brazing sheet of No. 20, Cu in the core material is less than 0.5% by mass, and Zn in the sacrificial material exceeds 5.0% by mass. The post-intensity could not be measured.

  Comparative Example No. The brazing sheets 7 and 20 are assumed to be the conventional brazing sheets described in Patent Document 1 or Patent Document 2. As shown in the present embodiment, these conventional brazing sheets do not satisfy a certain level of one or more of strength after brazing, brazing property, corrosion resistance, and electric resistance weldability. Therefore, this example objectively revealed that the brazing sheet according to the present invention is superior to the conventional brazing sheet.

  As described above, the aluminum alloy brazing sheet according to the present invention has been specifically described with reference to embodiments and examples for carrying out the invention, but the gist of the present invention is not limited to these descriptions, and Should be interpreted broadly based on the description. Needless to say, various changes and modifications based on these descriptions are also included in the spirit of the present invention.

Claims (2)

A core material containing Si: 0.1 to 1.0% by mass, Cu: 0.5 to 1.2% by mass, Mn: 0.5 to 2.0% by mass, with the balance being Al and inevitable impurities ,
Arranged on one side of the core material, Si: more than 0.2% by mass and 0.8% by mass or less, Zn: more than 3.0% by mass and 5.0% by mass or less, Mg: 1.0 to 4.5 A sacrificial material containing mass%, the balance being Al and inevitable impurities,
An aluminum alloy brazing sheet provided on the other surface side of the core material and comprising a brazing material made of an aluminum alloy,
An aluminum alloy brazing sheet, wherein an area occupation ratio of a Zn-Mg intermetallic compound having a particle diameter of 2.0 µm or more on the surface of the sacrificial material is 1.0% or less.   2. The core material according to claim 1, further comprising at least one selected from Ti: 0.05 to 0.25 mass%, Cr: 0.25 mass% or less, and Mg: 0.5 mass% or less. Aluminum alloy brazing sheet.