JP2009149936A - Aluminum alloy clad material for heat-exchanger for brazed-making pipe excellent in strength and brazing property, and aluminum alloy tube for heat-exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a heat-exchanger to be made thin in thickness and light in weight when using a clad material having a sacrificial material by improving the strength without impairing the brazing property and the workability. <P>SOLUTION: The sacrificial material is clad on the one-side surface of a core material which is composed of 0.1 to 0.3% Mg, 0.6 to 1.5% Si, 0.7 to 2.5% Cu, 0.05 to 0.5% Mn, and if necessary, 0.05 to 0.5% Zn and further, if necessary, one or two elements of 0.05 to 0.3% Zr and 0.05 to 0.3% Ti and the balance Al with inevitable impurities and further, satisfies such conditions that the composition ratio by mass% of Si, Mn and Fe is 12Si-(4Mn+3Fe)=6 to 15, and an Al-Si series brazing material is clad on the other-side surface of the core material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat exchanger tube manufactured by a brazing method, in particular, an automotive heat exchanger tube, and an aluminum alloy clad material for a heat exchanger for brazing pipe making suitable for manufacturing the tube.

Conventionally, a tube material of an automotive heat exchanger has a pipe material formed of a JIS3003 alloy as a core material, a JIS7072 alloy as a sacrificial material on one side, and a JIS4045 alloy as a brazing material on the other side. An electric resistance welded tube (hereinafter referred to as a non-brazed tube) for joining the butt portions by high-frequency heating has been used.
By the way, in recent years, for the purpose of reducing the weight of the heat exchanger and reducing the cost, the members used, particularly the tube material, tend to be thinner. However, the limit of thinning the non-brazed tube is about 0.20 mm due to the problem of formability. In order to achieve further thinning, the tube material is bent into a B shape so that the sacrificial material of the tube material is on the inside, and both sides are joined by brazing (hereinafter referred to as brazing mold). Tube) has been proposed (see, for example, Patent Document 1), and is becoming mainstream nowadays.

  In reducing the thickness of the member, it is necessary to increase the strength of the material to meet the thickness reduction. In the non-brazing tube, for example, as disclosed in Patent Document 2, Mg and Si are added to the sacrificial material, and the core material is improved in strength by using diffusion during brazing heat treatment. A method for improving the strength of the material itself has been proposed. However, since the sacrificial material becomes a joint surface in the brazed tube material, the brazing property is reduced when Mg is added to the sacrificial material, and therefore a method of adding a large amount of Mg to the sacrificial material is difficult to apply. .

For example, in Patent Document 3, Mg is added to the core material, and an intermediate layer is provided between the brazing material and the core material so that Mg diffuses from the core material to the brazing material. A four-layer material that suppresses the above has been proposed. However, the four-layer structure is not practical because it increases costs and is difficult to manufacture. Moreover, what is disclosed by patent document 4, 5 is aiming at the strength improvement by adding Mn to a core material, or adding Fe with Mn.
JP-A-2-75414 Japanese Patent Laid-Open No. 2-175093 JP 2006-131923 A Japanese Patent Laid-Open No. 10-130760 JP 11-315335 A

However, although the addition of Mn has the effect of increasing the material strength, the addition amount is limited due to manufacturing problems. Similarly, the addition of Fe increases the strength, but when the addition amount is large, problems such as a decrease in the self-corrosion resistance of the material and a decrease in formability due to the formation of giant crystallized products during casting occur. For molding into a brazed tube shape, the material is required to have high formability. Moreover, high strength as a tube material is also required for the product after molding to reduce the thickness. On the other hand, when the strength of the base material is increased, there is a problem that a shape defect occurs due to a spring back during molding into a B-shape, and it is necessary to satisfy these contradictory characteristics.
As described above, it can be said that it is extremely difficult to further improve the material strength from the viewpoints of brazing property, manufacturing (workability), corrosion resistance, and the like in the conventional invention material.

  The present invention has been made against the background of the above circumstances, and in brazed pipes, it is possible to improve the strength without impairing the brazability and workability, and thus the strength capable of reducing the thickness and weight, It is a basic object to provide an aluminum alloy clad material for a heat exchanger for brazing pipe making that is excellent in brazing, and more preferably, a member to be used is thinned to reduce the weight of an automotive heat exchanger. An object of the present invention is to provide an aluminum alloy tube for a heat exchanger.

  Accordingly, the present inventors have conducted extensive studies for the purpose of solving the problems in the prior art as described above and obtaining a clad material for brazing pipe making that satisfies both strength, brazing property and workability. By using an Al-low Mg-high Si-low Mn-high Cu alloy as the component of the material, the strength before brazing is such that the formability is not hindered, and after brazing, the MgSi compound is aged. Thus, the present inventors have found that the strength after brazing can be significantly improved and have completed the present invention. This will be specifically described below.

  That is, among the aluminum alloy clad materials for brazing tube heat exchangers excellent in strength and brazing property of the present invention, the first present invention is mass%, Mg is 0.1 to 0.3%, Si is 0.6-1.5%, Cu 0.7-2.5%, Mn 0.05-0.5%, the balance is made of Al and inevitable impurities, and the Si, Mn, Fe A sacrificial material is clad on one side of the core material satisfying the condition that the composition ratio is 12% by mass and 12Si- (4Mn + 3Fe) = 6-15, and an Al-Si brazing material is clad on the other side of the core material. It is characterized by.

  The aluminum alloy clad material for heat exchangers for brazing pipe making excellent in strength and brazing property according to the second aspect of the present invention, in the first aspect of the present invention, is further added to the core material by 0.05 to 0.5% by mass. % Zn is contained.

  The aluminum alloy clad material for a heat exchanger for brazing pipe making having excellent strength and brazing property according to the third aspect of the present invention is the above core material according to the first or second aspect of the present invention, further comprising 0.05 to It is characterized by containing one or two of 0.3% Zr and 0.05-0.3% Ti.

  An aluminum alloy tube for a heat exchanger according to a fourth aspect of the present invention is such that an end of the aluminum alloy clad material for a heat exchanger for brazing pipes according to any one of the first to third aspects of the present invention is bent inward. The end portion is brazed to the inner surface side of the aluminum alloy clad material to form a tube shape.

The Al alloy core material of the present invention is obtained by adding Mg and Si to Al, thereby precipitating and hardening due to fine precipitation of the Mg ₂ Si compound in the cooling process during the brazing treatment, and then aging precipitation and hardening due to artificial aging. In addition, the strength of the core material is greatly improved by dispersion strengthening with an Al—Mn—Si compound by addition of a small amount of Mn and solid solution hardening by addition of Cu. As for the invention of the present application, aging treatment after brazing may be carried out, but since the heat exchanger has heat at the time of use, aging precipitation is naturally made during use. Do not obligate. Furthermore, by satisfying 12Si- (4Mn + 3Fe) = 6 to 15 (both mass%), it was clarified that the best core material can be obtained from the viewpoint of strength and corrosion resistance, and the present invention has been achieved.

  The reason why the components of the core material in the present invention are limited will be described below. In addition, all the component content in the following is shown by the mass%.

(Core material)
Mg: 0.1 to 0.3%
Mg forms an Si and Mg ₂ Si compound, and has the effect of increasing the strength after brazing and the strength after artificial aging. If the content is less than the lower limit, the amount of Mg ₂ Si compound produced is small and the desired strength cannot be obtained. When the upper limit is exceeded, Mg generates flux and high melting point magnesium fluoride, which inhibits the action of the flux to remove the Al oxide film, resulting in reduced brazing. Furthermore, excessive Mg increases the yield strength of the material, so that the amount of springback during pipe forming increases and the formability decreases. Therefore, the Mg content is 0.1 to 0.3%. For the same reason, it is desirable that the lower limit is 0.15% and the upper limit is 0.3%.

Si: 0.6 to 1.5%
Si forms an Mg and Mg ₂ Si compound, and has the effect of increasing the strength after brazing and the strength after artificial aging. If the content is less than the lower limit, the above-described effects are not sufficiently exhibited. When the upper limit is exceeded, the melting start temperature of the core material decreases. Therefore, the addition amount is set to 0.6 to 1.5%. For the same reason, it is desirable to set the lower limit to 0.8% and the upper limit to 1.2%.

Cu: 0.7 to 2.5%
Cu has the effect of increasing the strength after brazing by solid solution strengthening and making the potential noble, so when added to the core material, it has the effect of increasing the potential difference from the sacrificial material and improving the corrosion resistance. In the case of the present invention, the Mg ₂ Si compound is precipitated prior to the precipitation of the Cu-based compound in the cooling process during brazing. In this case, precipitation of the Cu-based intermetallic compound is promoted, and a coarse Cu-based compound is precipitated around the Mg ₂ Si compound, so that the solid solubility of the matrix is lowered. Therefore, it is necessary to increase the Cu content in the core material of the clad material of the present invention as compared with the conventional alloy. If the content is less than the lower limit, the effect is small, and if the content exceeds the upper limit, the melting start temperature is lowered and the castability is remarkably lowered. Therefore, the addition amount is set to 0.7 to 2.5%. More preferably, the lower limit is 0.9% and the upper limit is 2.0%.

Mn: 0.05 to 0.5%
Inclusion of Mn has the effect of forming an Al—Mn—Si-based compound, improving the strength after brazing, and increasing the melting start temperature. However, since Mn is preferentially bonded to Si, the amount of dissolved Si is reduced, and the age-hardening property due to the Mg ₂ Si intermetallic compound is lowered, so that only a small amount is contained. If the content is less than the lower limit, the effect is not sufficiently exhibited. If the content exceeds the upper limit, the amount of dissolved Si is reduced as described above, and age-hardening is reduced. Therefore, the content is made 0.05 to 0.5%. For the same reason, it is desirable that the lower limit is 0.2% and the upper limit is 0.5%.

Zn: 0.05-0.5%
Zn has the effect of increasing the age-hardening property of the Mg ₂ Si compound, so it is contained in the core material as desired. If the content is less than the lower limit, the effect is small, and if it exceeds the upper limit, the melting start temperature is lowered. In addition, since Zn makes a potential lower, when added to the core material, the potential difference between the sacrificial material and the brazing material is reduced and the corrosion resistance is reduced, but in the case of the composition range of the core material of the present invention, the effect Such inconvenience does not occur because of the decrease of. Therefore, the addition amount is set to 0.05% to 0.5%. For the same reason, it is desirable that the lower limit is 0.1% and the upper limit is 0.3%.

Zr: 0.05-0.3%
Ti: 0.05-0.3%
Zr and Ti form an Al ₃ Zr-based compound or an Al ₃ Ti-based compound during the homogenization treatment and have an effect of increasing the strength of the material. Therefore, one or two of Zr and Ti are added to the core as desired. If the content is less than the lower limit, the effect is small. If the content exceeds the upper limit, a giant compound is formed at the time of casting, and the moldability is lowered. Therefore, the content is 0.05% to 0.3%, respectively.

12Si- (4Mn + 3Fe) = 6-15
The strength of the material of the present invention is mainly due to precipitation hardening of the Mg ₂ Si compound. The precipitation hardening of Mg ₂ Si becomes better as the amount of dissolved Si increases. The amount of solid solution Si preferentially forms Mn added at the same time, Fe, which is an inevitable impurity, and Al—Mn—Si—Fe compound, and Al—Si—Fe compound. Decrease. The composition ratio of Mn and Si in the Al—Mn—Si—Fe compound is Mn: Si = 3: 1, and the composition ratio of Fe and Si in the Al—Si—Fe compound is Fe: Si = 4: 1. Therefore, when both elements are present, the amount of solute Si is solute Si amount = Si addition amount-1 / 3 Mn addition amount-1 / 4 Fe addition amount (both mass%). If the composition range is less than the lower limit, the effect is small, and if it exceeds the upper limit, the corrosion resistance decreases. Therefore, the composition range is set to 12Si- (4Mn + 3Fe) = 6-15. More preferably, the lower limit of the composition range 12Si- (4Mn + 3Fe) is 9 and the upper limit is 15.

In the present invention, the composition of the sacrificial material provided on one side of the core material is not limited to a specific one, but when an Al- (Zn) -Si-based sacrificial material is provided on one side of the core material, the sacrificial material is sacrificed from the core material. The strength difference between the core material and the sacrificial material is reduced by forming the Si and Mg ₂ Si compound added to the sacrificial material by Mg diffusion into the material and improving the strength of the sacrificial material. Interfacial strength is improved by forming a large amount of Mg ₂ Si compound near the core / sacrificial material interface due to Mg diffusion and Si diffusion from the sacrificial material to the core material, and good hot workability due to both effects become. This is because a large amount of Cu added to the core material of the present invention distorts the crystal lattice of the core material matrix, thereby facilitating the diffusion of Si from the sacrificial material to the core material.
Furthermore, in the present invention, since Si added to the sacrificial material and Mg added to the core material form an Mg ₂ Si compound, Mg diffusion from the core material to the surface of the sacrificial material is suppressed, and the brazing property is remarkably improved.

Also, in the case of a tube material in which Mg is added to the core material, Si diffuses from the brazing material combined on one side of the core material to the core material to form an Mg ₂ Si compound, thereby improving the strength. A gradient having an intensity peak is formed on the brazing filler metal side. When combined with an Al—Zn-based sacrificial material, only the strength of the core material near the interface between the brazing material and the core material is increased, so that the strength balance of the core material may be poor and the moldability may be adversely affected. . However, in the present invention, as described above, due to Si diffusion from the sacrificial material, a strength gradient is formed with a peak at the same part of the interface from the sacrificial material / core material interface to the core material. Therefore, the strength gradient in the core material is eliminated and the strength of the entire core material is improved. As a result, the moldability is improved and the strength can be increased.

Below, the composition example suitable as a sacrificial material provided in the single side | surface of a core material by this invention is shown.
That is, Si: 0.2-1.6%, Mn: 0.2-1.0%, Mg: 0.05% or less, Zn: 2.5-5.0%, Ti: 0.05-0 .3%, optionally containing one or two of Zr: 0.05 to 0.3%, Cr: 0.05 to 0.3%, the balance being Al and inevitable impurities Is illustrated.

  As described above, according to the present invention, by mass, Mg is 0.1 to 0.3%, Si is 0.6 to 1.5%, Cu is 0.7 to 2.5%, Mn 0.05-0.5%, optionally 0.05-0.5% Zn, and optionally 0.05-0.3% Zr, 0.05-0.3% 1 or 2 of Ti, the balance is made of Al and inevitable impurities, and the composition ratio of Si, Mn, and Fe is 12%-(4Mn + 3Fe) = 6 to 15 in terms of mass%. A sacrificial material is clad on one side of the core material, and an Al-Si brazing material is clad on the other side surface of the core material. 1. Further increase in strength can be achieved. 2. easy to manufacture; 3. Improve brazability. A high value such as good moldability can be imparted, and a tube for a heat exchanger having even higher characteristics can be obtained.

  In the aluminum alloy clad material of the present invention, the aluminum alloy constituting the core material, the sacrificial anode material and the brazing material is usually ingoted by semi-continuous casting, homogenized, and then hot-rolled to a predetermined thickness. . Each plate material can be obtained by continuous casting and rolling. As the core material and sacrificial anode material, an aluminum alloy having the above-described composition is used. Also, the composition of the brazing material is not limited to a specific one in the present invention, but an Al—Si based alloy generally used as a brazing material can be used.

These materials are manufactured through a process of combining the core material, the sacrificial anode material, and the brazing material, forming a clad material by hot rolling, and finally cold rolling to a predetermined thickness.
Mg ₂ Si compounds and Al—Mn—Si compounds are produced in the production process of the clad material, but the size and distribution of these precipitates are mainly determined by the heat treatment conditions during production, so that crystals for obtaining desired physical properties are obtained. The following production method is suitable for the precipitation state.

  The homogenization treatment of the core material is desirably held at a temperature of 350 to 550 ° C, more preferably 400 to 500 ° C for 2 hours or more.

  Also, the distribution of precipitates changes during brazing heat treatment, but if brazing heat treatment (heated to 590 to 600 ° C. and then cooled at a cooling rate of 100 ° C./min or less) is performed, during brazing cooling And after that, age hardening occurs during use as a heat exchanger, and the strength can be increased. Preferably, the average rate of temperature rise from room temperature to the highest temperature is 80 ° C./min or higher.

  The clad material 1 obtained above has an aluminum alloy brazing material 3 clad on one surface of the core material 2 and a sacrificial anode material 4 clad on the other surface of the core material 2 as shown in FIG. Yes. This aluminum alloy clad material 1 is bent and formed into a tubular shape (made into a tube) so that the sacrificial anode material 4 becomes the inner surface of the tube. In the form shown in FIG. 1, as shown in FIG. 1 (b), both end sides of the aluminum alloy clad material 1 are in close contact with the center portion of the inner surface to form the inner pillar portion 1 a, and the refrigerant path 5 is formed on both sides thereof. 5 is secured. Further, the aluminum alloy brazing material 3 located on the outer surface side of the pipe is brought into close contact with a fin or the like (not shown) to perform brazing heating. The heating conditions, atmosphere, and flux type in brazing are not particularly limited as the present invention. At the time of brazing, the sacrificial anode material 4 exhibits good wettability with the brazing, and the inner surface of the tube and the end of the aluminum alloy clad material 1 are well bonded by the formation of the fillets 6 and 6.

  An aluminum alloy for a core material having the chemical components (remaining Al and inevitable impurities) shown in Table 1, and an aluminum alloy for a sacrificial material (corresponding to JIS7072 alloy) having the chemical components (remaining Al and inevitable impurities) shown in Table 2; Alloys for materials (equivalent to JIS 4045 alloy: Al-10.5% Si, the balance Al and inevitable impurities) were each cast by semi-continuous casting. As the brazing material, a JIS 4343 alloy or an Al—Si alloy containing Mg, Cu, Li or the like can be used.

Using the above-mentioned aluminum alloy for core material, homogenization treatment, hot rolling, cold rolling, and intermediate annealing were performed, and an H14 tempered core material testing plate material having a thickness of 0.20 mm was obtained by final cold rolling. .
Further, as shown in Table 3, the homogenized alloy ingot for sacrificial material is combined on one side of the ingot for core material and the alloy ingot for brazing material is combined on one side as shown in Table 3. Hot rolled to obtain a clad material. Further, cold rolling and intermediate annealing were performed, and an H14 tempered clad material having a thickness of 0.20 mm was produced by final cold rolling. The thickness configuration of the clad material was sacrificial material: core material: brazing material = 20: 65: 15.

(Evaluation items for core material)
[Strength after brazing]
The prepared core material test plate is heated in a high-purity nitrogen gas atmosphere at an average temperature increase rate of 100 ° C./min. After reaching 595 ° C., it is cooled to 300 ° C. at an average temperature decrease rate of 100 ° C./min. After performing heat treatment equivalent to brazing, aging treatment was carried out at 80 ° C. for 15 days. Then, the sample was cut out in parallel with the rolling direction, the JIS13B test piece was produced, the tensile test was implemented, and the tensile strength was measured. The measurement results are shown in Table 1. With respect to the strength, 230 MPa or more was evaluated as ２２０, 220 to 230 MPa as ◯, 180 to 220 MPa as Δ, and 180 MPa or less as ×, and the evaluations are shown in Table 1.

[Formability]
The material before brazing was subjected to 90 ° bending processing assuming the inner column portion processing of the B-type tube, and the shape after molding and the amount of spring back at the same portion were measured.
As a result of the measurement, a shape having a good shape and a small springback amount was evaluated as ◯, a shape having a good shape and being in the springback amount was evaluated as △, and a shape having a poor shape or a large amount of springback was evaluated as ×. In the above-described evaluation of formability, the strength before brazing was high, and when Mg exceeded the upper limit or when the amount of Fe was large, Δ or ×.

[Corrosion resistance]
A 30 mm × 80 mm corrosion test piece was cut out from the sample subjected to the brazing equivalent heat treatment, and SWAAT based on the ASTM standard was performed for 2 days. Then, the cross-section observation of the corrosion part was implemented and the presence or absence of intergranular corrosion was observed.
As a result of the observation, those having no intergranular corrosion sensitivity were evaluated as ◯, those having slight sensitivity as Δ, and those having high sensitivity as ×, and the evaluation is shown in Table 1.

[Melting point]
About the board | plate material for a core material test, solidus line temperature was measured by DTA (Differential Thermal Analysis). The temperature rising rate was 5 ° C./min. The measurement results are shown in Table 1. In addition, assuming that the maximum reached temperature during brazing was 585 to 595 ° C., the presence or absence of melting of the core material during brazing was evaluated based on the solidus temperature. In this evaluation, the melting point of 595 ° C. or higher was evaluated as “◯”, 590-595 ° C. as Δ, and 590 ° C. or lower as “X”.

[Manufacturability]
In each process of casting, hot rolling, and cold rolling, the presence or absence of defects was evaluated.
(Casting: casting cracks, presence or absence of giant crystals, hot rolling: cracking, peeling, side cracks, cold rolling: side cracks)
In the above, no casting crack and no formation of giant intermetallic compound ○, minor casting crack or slight production of giant intermetallic compound △, severe casting crack, or large amount of metal Those having intermetallic compound formation were evaluated as x, and the evaluation is shown in Table 1.

The core material test plate materials shown in A to J satisfy the core material composition of the present invention, all the properties are good, and are evaluated as ◯ or ◎ for comprehensive evaluation. In the C-J core material test plate, 12Si- (4Mn + 3Fe) was 9-15, so that the strength was particularly excellent.
In the K core material test plate, since Si and Cu exceeded the upper limit of the present invention, the melting point was lowered and the productivity was difficult. The overall evaluation was x.
Since the core material test plate of L exceeded the upper limit of the present invention, the brazing property decreased. The overall evaluation is △.
The M core material test plate was insufficient in strength because Si was less than the lower limit of the present invention. The overall evaluation is △.
Since the core material test plate of N had 12Si- (4Mn + 3Fe) exceeding the upper limit of the present invention, the corrosion resistance was lowered. The overall evaluation is △.
The O core material test plate had insufficient strength because 12Si- (4Mn + 3Fe) was less than the lower limit of the present invention. The overall evaluation is △.

(Evaluation items for clad materials)
[Strength]
The clad material produced as described above is heated at an average temperature increase rate of 100 ° C./min in a high-purity nitrogen gas atmosphere. After reaching 595 ° C., the clad material is cooled to 300 ° C. at an average temperature decrease rate of 100 ° C./min. After heat treatment corresponding to brazing, an aging treatment was performed at 80 ° C. for 15 days. Then, the sample was cut out in parallel with the rolling direction, the JIS13B test piece was produced, the tensile test was implemented, and the tensile strength was measured. The results are shown in Table 3. With respect to the strength, 230 MPa or more was evaluated as ◎, 210-230 MPa as ◯, 200-210 MPa as Δ :, and 200 MPa or less as ×, and the evaluation is shown in Table 3.

[Brassability]
As shown in FIG. 2, a clad material was used as a seat plate and a vertical material, and a reverse T-shaped test was performed so that the sacrificial material side of the clad material used as the seat plate was in contact with the vertical material, and a cross-section of the joint was observed. . The flux was brazed by applying about 4 g / m ² only to the seat plate. In this brazing, the soundly joined ones were evaluated as “◯”, those that could be joined but having voids were evaluated as “Δ”, and those that could not be joined were evaluated as “X”.

[Formability]
The clad material was bent at 90 ° assuming that the sacrificial material was inside, and the inner column portion of the B-type tube was processed, and the shape after molding and the amount of spring back at the same portion were measured.
As a result of the measurement, a shape having a good shape and a small amount of springback was evaluated as ◯, a shape having a good shape and being in the amount of springback was evaluated as △, and a shape having a poor shape or a large amount of springback was evaluated as ×. Indicated.

[Corrosion resistance]
A 30 × 40 mm sample was cut out from the clad material sample after brazing heat treatment, and the sacrificial material side was in an aqueous solution containing Cl ⁻ : 195 ppm, SO ₄ ²⁻ : 60 ppm, Cu ²⁺ : 1 ppm, Fe ³⁺ : 30 ppm. The immersion test was conducted for 8 weeks in a cycle of 80 ° C. × 8 hr → room temperature × 16 hr, and the cross section of the maximum corrosion portion was observed. As a result, the case where corrosion stopped in the sacrificial material layer was evaluated as ○, the sacrificial material layer or more to the corrosion depth of half the plate thickness was evaluated as △, and the corrosion depth was evaluated as half the plate thickness as ×. The evaluation is shown in Table 3.

As a result of each of the above evaluations, the sample no. In No. 8, the sacrificial material was No. c, sample no. The strength was higher than 1 (strength ○ → ◎). Sample No. In No. 9, the sacrificial material was No. c, sample no. The strength was higher than 2 (strength ○ → ◎).
As shown in Table 2, three types of sacrificial materials were used: Al—Zn, Al—Zn—Mn—Fe, and Al—Zn—Si— (Mn, Fe). The core material of the present invention can provide good characteristics when combined with any sacrificial material, but when combined with an Al-Zn-Si- (Mn, Fe) -based material, further improvement in strength can be expected.

It is a figure which shows the manufacture flow of the pipe | tube using the aluminum alloy clad material of one Embodiment of this invention. Similarly, it is a figure explaining the test method of the brazing property of the clad material in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum alloy clad material 2 Core material 3 Aluminum alloy brazing material 4 Sacrificial anode material

Claims (4)

  In mass%, Mg is 0.1 to 0.3%, Si is 0.6 to 1.5%, Cu is 0.7 to 2.5%, Mn is 0.05 to 0.5%, The balance is made of Al and inevitable impurities, and the sacrificial material is clad on one side of the core material satisfying the condition that the composition ratio of Si, Mn, Fe is 12 Si- (4Mn + 3Fe) = 6-15 in terms of mass%, An aluminum alloy clad material for heat exchangers for brazing pipes, which is excellent in strength and brazing properties, characterized in that an Al-Si brazing material is clad on the other surface of the core material.   The aluminum alloy clad for heat exchangers for brazing pipes according to claim 1, wherein said core material further contains 0.05 to 0.5% Zn by mass%. Wood.   The core material further comprises one or two of 0.05 to 0.3% Zr and 0.05 to 0.3% Ti in mass%. Or the aluminum alloy clad material for heat exchangers for brazing pipe making excellent in the strength and brazing property described in 2.   The end portion of the aluminum alloy clad material according to any one of claims 1 to 3 is bent inward, and the end portion is brazed to the inner surface side of the aluminum alloy clad material to form a tube shape. An aluminum alloy tube for heat exchangers.

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