JP5354910B2 - Aluminum heat exchanger and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger which is superior in corrosion resistance and strength, and is made from aluminum, and to provide a manufacturing method therefor. <P>SOLUTION: The heat exchanger 1 made from aluminum includes a core part 4 that is formed of a tube 2 in which a working fluid is circulated, and a fin 3 that is joined to the outer surface of the tube 2. The core part 4 is composed of the tubular tube material 2 and the bare fin member 3 joined thereto by a brazing technique with the use of a brazing filler metal component containing Si. The bare fin member 3 includes one or more elements among 0.001 to 5.0% (mass%, hereinafter the same) Sr, 0.001 to 5.0% Na and 0.001 to 5.0% Sb, 0.1 to 3.0% Mn, and the balance Al with unavoidable impurities. It is preferable for the bare fin member 3 to further include one or more elements among 0.1 to 5.0% Zn, 0.001 to 0.3% In and 0.001 to 0.3% Sn. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  In the present invention, for example, a tube material (working fluid passage constituting member) in which a brazing material is arranged on the surface of a core material and a bare fin material, such as an automobile condenser, an evaporator, a radiator, a heater, an intercooler, and an oil cooler The present invention relates to an aluminum heat exchanger having a core portion assembled by brazing and a manufacturing method thereof.

  Aluminum alloy heat exchangers made of an aluminum alloy having good lightness and thermal conductivity are widely used as, for example, automobile condensers, evaporators, radiators, heaters, intercoolers, and oil coolers. A heat exchanger made of an aluminum alloy is generally configured by brazing and joining a fin material and a tube material (working fluid passage component).

  A heat exchanger generally includes a core portion composed of a tube through which a working fluid flows, fins brazed to the outer surface of the tube, headers brazed to both ends of the tube, and outermost fins. It is composed of a side plate brazed to the header, a tank brazed or caulked to the header, and the like.

As a material constituting the tube material 92, for example, a brazing sheet in which a brazing material 922 containing Si grains 925 is clad on the surface of the core material 921 as shown in FIG. 3 is used.
As shown in FIG. 3 and FIG. 4, the brazing material 922 clad on the surface of the core material 921 is melted by assembling and heating the fin material 91 and the tube material 92. The fin material 91 and the tube material 92 are brazed and joined by filling the gaps or forming the fillet 923.

  The fin material is required to have a sacrificial anode effect to prevent the tube material from corroding by preferentially corroding the fin material over the tube material and fillet, and also prevents deformation due to high temperature heating during brazing and wax erosion. In order to prevent this, high temperature buckling resistance is required, and various materials have been proposed so far (Patent Document 1).

Further, as shown in FIG. 4, the brazing material structure of the tube material after brazing forms a non-uniform structure interspersed with plate-like or needle-like coarse single Si (924).
This plate-like or needle-like simple substance Si is noble than the brazing filler metal matrix and thus becomes a local cathode and induces local corrosion. As shown in FIG. 5A, when local corrosion occurs in the fillet 923, the fins 91 are dropped from the tube 92 as shown in FIG. And the sacrificial anode effect of a fin is lost and premature penetration corrosion arises in a tube. Further, as shown in FIG. 6A, when local corrosion occurs in the brazing material 922 of the flat portion of the tube 92, the sacrificial anode of the fin 91 does not sufficiently act as shown in FIG. 6B. Premature penetration corrosion occurs in the tube 92.

In order to improve local corrosion, it is effective to suppress the formation of plate-like or needle-like coarse single Si, and tube material is used as an improvement process for plate-like or needle-like single Si (miniaturization of single Si). A technique of adding Sr to brazing filler metal is known (Patent Document 2).
However, although an effect for suppressing the generation of plate-like or needle-like coarse single Si is obtained, it is not sufficient.

In addition, plate-like and needle-like coarse single-piece Si generated by a combination of a conventional fin material and tube material causes stress concentration at that portion when stress is applied during use of a heat exchanger, so the durability life is shortened. It was a factor to decrease.
Such a problem is not limited to the case where the tube material and the fin material made of the clad material are brazed and joined, but the plate-like plate material made of the clad material, the brazing material powder on the surface, and the brazing material. A problem also occurs when a tube material or a plate material made of an extruded profile coated with a brazing material component such as a flux that sometimes produces a brazing material is brazed and joined.

Japanese Patent Laid-Open No. Sho 62-120455 JP 2003-39194 A

  This invention is made | formed in view of this conventional problem, Comprising: It aims at providing the aluminum heat exchanger excellent in corrosion resistance and intensity | strength, and its manufacturing method.

1st invention is an aluminum heat exchanger which has a core part which consists of a tube which a working fluid distributes, and a fin joined to the outer surface of the tube,
The core part is configured by brazing and joining a tubular tube material and a bare fin material using a brazing material component containing Si,
The bare fin material is one or two of Sr: 0.01 to 1.0 % (mass%, hereinafter the same), Na: 0.01 to 0.02 %, Sb: 0.01 to 1.0 %. It is an aluminum heat exchanger characterized in that it contains seeds or more and Mn: 0.1 to 3.0%, and the balance consists of Al and inevitable impurities (Claim 1).

  As described above, the aluminum heat exchanger of the present invention is configured by brazing and joining a tubular tube material and a bare fin material having the above specific composition using a brazing material component containing Si. It has a core part. Therefore, an aluminum heat exchanger having excellent corrosion resistance and strength can be obtained.

Usually, when performing brazing joining, heating is performed at a temperature higher than the melting point of the brazing material component and lower than the melting point of the bare fin material to be joined. Therefore, the material improvement has been promoted by paying attention only to the brazing filler metal component which is a melted portion.
However, as a result of numerous experiments by the present inventors, it has been found that a part of the bare fin material in contact with the brazing filler metal component melts during brazing heating. In the present invention, the melting at the time of brazing of the bare fin material is positively utilized to improve the brazing material component structure.

The bare fin material includes Sr, Na, and Sb, which are effective elements for refining simple substance Si, Sr: 0.001 to 5.0%, Na: 0.001 to 5.0%, and Sb: 0.001. It contains 1 type or 2 types or more among -5.0%.
That is, a part of the bare fin material having the above composition of the present invention is melted by brazing heating performed by interposing a brazing filler metal component containing Si between the bare fin material and the tube material, and Sr therein , Na, or Sb dissolves into the molten brazing filler metal component together with the other components of the bare fin material.

  As described above, when at least one of Sr, Na, and Sb is supplied from the fin material side to the brazing material component, when the brazing material component re-solidifies, the Sr, Na, and Sb become the brazing material component. It acts as an improved material. As a result, the elemental Si that crystallizes in the brazing filler metal component after brazing can be refined, and the generation of plate-like or needle-like coarse elemental Si at the joint between the tube material and the bare fin material is prevented. Can be suppressed.

  As a result, it is possible to suppress the phenomenon such as the occurrence of local corrosion and stress concentration when stress is applied when using the heat exchanger as described above. In other words, the corrosion resistance of the core tube can be increased, the sacrificial anode effect of the fins can be demonstrated more reliably, and the stress concentration can be reduced when stress is applied when using a heat exchanger. Therefore, the durable life of the heat exchanger can be improved.

The bare fin material contains 0.1 to 3.0% of Mn.
Mn can form a solid solution and generate an Al—Mn-based compound (for example, Al ₆ Mn) to improve the strength of the bare fin material before and after brazing. Moreover, high temperature buckling resistance and molding processability can be improved. Therefore, the obtained core part can have high strength.
Thus, according to the present invention, an aluminum heat exchanger excellent in corrosion resistance and strength can be obtained.

  Moreover, such an effect of the present invention is not only exhibited when the brazing filler metal component itself does not contain Si grain refining elements such as Sr, Na, and Sb. Even when Si grain refining elements are contained in the brazing filler metal component, it can be compensated from the bare fin material side even if they are reduced due to oxidative consumption or erosion during melting, and the action of the present invention is effective. It is expressed and an excellent effect is obtained.

A second invention is a method of manufacturing an aluminum heat exchanger having a core portion made of a tube through which a working fluid flows and fins joined to the outer surface of the tube,
Sr: 0.01 to 1.0 % (mass%, the same applies hereinafter), Na: 0.01 to 0.02 %, Sb: 0.01 to 1.0 %, one or more, and Mn : 0.1 to 3.0%, with the balance being a combination of a bare fin material composed of Al and unavoidable impurities and a tubular tube material with a brazing filler metal component containing Si, and then the brazing The tube material and the bare fin material are brazed and joined by heating at a temperature higher than the melting point (solidus temperature) of the material component and lower than the melting point (solidus temperature) of the bare fin material, and the core In the method for manufacturing an aluminum heat exchanger, the portion is formed (claim 6).

As described above, the manufacturing method of the aluminum heat exchanger is a combination of the tube material and the bare fin material having the specific composition with a brazing filler metal component containing Si, and the soldering is performed at the temperature condition described above. A core part is formed by attaching. Therefore, as described above, an aluminum heat exchanger having excellent corrosion resistance and strength can be obtained.
That is, according to the present invention, an aluminum heat exchanger having excellent corrosion resistance and strength can be manufactured.

The core part which comprises the aluminum heat exchanger of 1st invention is comprised by brazing and joining a tubular tube material and a bare fin material using the brazing material component containing Si, as mentioned above. ing.
Examples of the tube material include an extruded profile that is formed into a tube shape (tubular) at the time of molding, and a tube-shaped material that is molded into a tube shape.

  Moreover, the brazing filler metal component containing Si can be easily interposed between the bare fin material and the tube material by arranging in advance on the surface of the tube material. In this case, when the brazing material component is integrally disposed on the surface of the tube material, or when the brazing material component is applied to the surface of the tube material at the time of brazing and joining, Etc.

  As an example in which the brazing material component is integrally disposed on the surface of the tube material, a brazing sheet in which a brazing material containing Si (brazing material component) is clad is bent and welded on the surface of the core material. The tube material made into the shape of a flat tube and the tube material made into the tube shape without welding only by bending a brazing sheet are mentioned.

  In addition, as an example in which a brazing filler metal component is applied to the surface of the tube material, a brazing filler metal powder such as an Si alloy, an aluminum alloy powder containing at least Si, , Si, and a brazing material component such as a flux that forms a brazing material when brazed is applied.

The brazing material component may be any alloy as long as it has a melting point lower than that of the bare fin material and the tube material. For example, Si powder, Al—Si alloy, Al—Si— Mg alloy, containing Al-Si-Mg-Bi alloy, Al-Si-Zn alloy, an aluminum alloy powder containing at least Si, such as Al-Si-Cu based alloy or the like, Si, such as K ₂ SiF ₆ A flux or the like that forms a brazing material during brazing can be used.
Moreover, it is preferable that the brazing filler metal component contains one or more of Sr, Na, and Sb. Moreover, it is more preferable that the brazing filler metal component contains the same element as the element contained in the bare fin material among Sr, Na, and Sb.

  The tube material is not particularly limited as long as it can be used as a tube material for a heat exchanger, but is pure Al, Al-Cu alloy, Al-Mn alloy, Al-Mn-Cu alloy, An Al—Cu—Mn—Mg alloy or the like can be used.

Further, the bare fin material constituting the core portion, Sr: 0.01 ~ 1.0%, Na: 0.01 ~ 0.02%, Sb: 1 kind of 0.01 to 1.0%, or 2 or more types and Mn: 0.1 to 3.0% are contained.

When the bare fin material contains Sr, the content needs to be 0.001 to 5.0%.
When the Sr content is less than 0.001%, the above-described effects cannot be obtained sufficiently. On the other hand, when the said content exceeds 5.0%, there exists a possibility that manufacture of a bare fin material may become difficult. Therefore, the content of Sr is 0.01 to 1.0%.

Moreover, when the said bare fin material contains Na, the content needs to be 0.001-5.0%.
When the content of Na is less than 0.001%, the above effect cannot be obtained sufficiently. On the other hand, when the said content exceeds 5.0%, there exists a possibility that manufacture of a bare fin material may become difficult. Therefore, the content of Na is a 0.01 to 0.02%.

Moreover, when the said bare fin material contains Sb, the content needs to be 0.001-5.0%.
When the Sb content is less than 0.001%, the above-described effects cannot be obtained sufficiently. On the other hand, when the said content exceeds 5.0%, there exists a possibility that manufacture of a bare fin material may become difficult. Therefore, the content of Sb is 0.01 to 1.0%.

  If the Mn content is less than 0.1%, the above effects may not be sufficiently obtained. On the other hand, when the content of Mn exceeds 3.0%, coarse crystallized products are generated during casting, and rolling workability is impaired. As a result, it is difficult to obtain a sound plate material. The content of Mn is preferably 0.5 to 1.7%.

  Further, the balance of the bare fin material is made of Al and inevitable impurities. Examples of the inevitable impurities include the following, for example, Fe: 0.7% or less, Si: 0.5% or less, Cu: 0.1% or less, Mg: 0.05% or less, Examples include Cr: 0.1% or less, Zn: 0.3% or less, Ti: 0.1% or less, and the like.

The bare fin material is added with a small amount of Ti, Cr, Zr, V, B: 0.3% or less, Cu: 0.2% or less, Mg: 0.3% or less, etc., as necessary. May be.
Ti is divided into a high-concentration region and a low region in the plate thickness direction of the bare fin material, and they are in a layered form in which they are alternately distributed, thereby increasing the anticorrosion life of the bare fin material.
Cr, Zr, V, and B increase the recrystallization temperature during brazing heating and suppress the erosion during brazing heating by increasing the crystal grain size of the bare fin material.
Cu improves the strength of the bare fin material by solid solution.

  In addition, the method for producing the bare fin material is not particularly limited, but after ingot is prepared and homogenized by continuous casting, hot rolling is performed, and then cold rolling is appropriately performed. And a method of performing intermediate annealing and cold rolling, a method of preparing a plate material by continuous casting and rolling, and then appropriately performing cold rolling, intermediate annealing and cold rolling. And it is preferable to manufacture the said bare fin material especially by making the molten metal of aluminum alloy into a board | plate material of thickness 1-20mm directly by continuous casting rolling, and also performing cold rolling and heat processing suitably. In this case, by increasing the solid solubility of Si grain refining elements such as Sr, Na, Sb, etc. by continuous casting and rolling, and by refining the grain size of the crystallization product of the Si grain refining elements, the bare fin material It is possible to make it easier to dissolve the Si grain refining element from the brazing material to the tube material.

In the first invention and the second invention, the bare fin material constituting the core portion may further include Zn: 0.1 to 5.0%, In: 0.001 to 0.3%, Sn: It is preferable to contain 1 type (s) or 2 or more types among 0.001 to 0.3% (Claims 2 and 7).
In addition, also when the said Zn, In, and Sn contain as an unavoidable impurity, when the said range is satisfy | filled, the below-mentioned effect can be acquired.

Zn makes the potential of the bare fin material low and gives a sacrificial anode effect.
When it contains Zn, the content needs to be 0.1 to 5.0%.
When the Zn content is less than 0.15%, the above-mentioned effects cannot be obtained sufficiently. On the other hand, when the content exceeds 5.0%, the self-corrosion resistance of the bare fin material itself is deteriorated. There is a fear.

The In and Sn make the potential of the bare fin material base and give a sacrificial anode effect.
In the case of containing In and Sn, the contents must be 0.001 to 0.3%, respectively.
When the content of In and Sn is less than 0.001%, the above-described effect cannot be obtained sufficiently. On the other hand, when the content exceeds 0.3%, the self-feature of the bare fin material itself Corrosion resistance may deteriorate.

Further, the bare fin material constituting the core part is further Si: less than 3.0% (a range not exceeding the content of Mn), Fe: less than 3.0% (a range not exceeding the content of Mn) It is preferable to contain at least one of (claims 3 and 8).
In addition, also when the said Fe and Si are contained as an unavoidable impurity, when the said range is satisfy | filled, the below-mentioned effect can be acquired.

In addition, Fe is dissolved, and an Al-Fe compound, an Al-Fe-Si compound, an Al-Mn-Fe-Si compound (specifically, Al ₃ Fe, α-AlFeSi, MnFeAl ₆ ) to improve the strength of the bare fin material and reduce the solid solution amount of Mn to improve the thermal conductivity.
And when it contains Fe, the content needs to be less than 3.0% (range which does not exceed content of Mn).
When the Fe content is 3.0% or more, a coarse crystallized product is generated at the time of casting and the rolling processability is impaired. As a result, it is difficult to obtain a sound plate material. Further, when the Fe content exceeds the Mn content, the strength may decrease. The Fe content is preferably 1.5% or less (in a range not exceeding the Mn content).

In addition, Si dissolves and generates Si and Al—Mn—Si compounds (specifically, Mn ₂ SiAl _{10 and the} like) to improve the strength of the bare fin material and reduce the solid solution amount of Mn. To improve the thermal conductivity.
And when it contains Si, the content needs to be less than 3.0% (the range which does not exceed the content of Mn).
If the Si content is 3.0% or more, the bare fin material may melt during brazing. Further, if the Si content exceeds the Mn content, the moldability may be reduced. The Si content is preferably 1.5% or less (a range not exceeding the Mn content).

In the first and second aspects of the invention, the tube material is preferably made of a clad material in which a brazing material containing the brazing material component is disposed on the surface of the core material by clad bonding. 4, 9).
The tube material made of the clad material only needs to have a brazing filler material component disposed on at least the side to be joined to the bare fin material, for example, a two-layer clad material in which a brazing material is clad on one side of a core material, or A brazing material on one side of the core material and a three-layer clad material clad with a brazing material or a sacrificial anode material made of an Al-Zn alloy on the other surface is bent and welded into a flat tube shape. A tube shape or the like can be used without being welded simply by bending.

The clad material can be manufactured, for example, by superposing and heating the core material and the brazing material, performing hot rolling, and then performing cold rolling.
When a two-layer clad material is used, it is preferable that the clad material thickness T is 0.2 to 1.0 mm, where T is the total clad material thickness and t1 is the brazing material thickness. The clad rate (t1 / T) of the brazing material is preferably 5 to 20%.

  In addition, when a three-layer clad material is used, the total thickness of the clad material is T, the thickness of the brazing material disposed on the surface to be joined to the bare fin is t1, and the brazing material is disposed on the other surface. When the thickness of the brazing material is t2, and the thickness of the sacrificial anode material when the sacrificial anode material is arranged is t3, the plate thickness T of the clad material is preferably 0.2 to 1.0 mm. The clad rate (t1 / T) is preferably 5 to 20%, the clad rate (t2 / T) is preferably 5 to 20%, and the clad rate (t3 / T) is 5 to 25%. It is preferable that

  As the core material of the cladding material, for example, pure Al, Al—Cu alloy, Al—Mn alloy, Al—Mn—Cu alloy, Al—Cu—Mn—Mg alloy, or the like can be used.

As the brazing material of the clad material, any alloy may be used as long as it has a melting point lower than that of the core material and the bare fin material. For example, Al—Si alloy, Al—Si—Mg alloy, Al—Si An Mg—Bi alloy, an Al—Si—Zn alloy, an Al—Si—Cu alloy, or the like can be used.
The brazing material preferably contains one or more of Sr, Na, and Sb. Moreover, it is more preferable that the brazing material contains the same element as the element contained in the bare fin material among Sr, Na, and Sb.

Moreover, it is preferable that the said core part further has the site | part formed by brazing the said bare fin material and a plate-shaped plate material using the brazing material component containing Si.
The portion formed by brazing and joining the bare fin material and the plate material is a combination of the bare fin and the plate material exhibiting a plate-like shape that is not tubular, with a brazing filler metal component containing Si interposed therebetween. It can be formed by performing brazing and joining by heating (claim 10).

  The plate-like plate material and the bare fin material are brazed and bonded using the brazing material component, and the brazing material component exists between the plate material and the bare fin material during brazing and joining. There is a case where the brazing material component is integrally disposed on the surface of the plate material, or a case where the brazing material component is applied on the surface of the plate material.

  The example in which the brazing material component is integrally disposed on the surface of the plate material and the example in which the brazing material component is applied to the surface are the same as in the case of the tube material described above.

In addition, when the brazing filler metal component other than the Si-containing flux that generates the brazing filler during brazing is used as the brazing filler metal component, the brazing filler metal is usually not generated on the surface of the tube member or the plate member. Of course, it is also possible to apply this flux.
And even if it is the above-mentioned Si-containing flux or ordinary flux, these fluxes are formed into a desired shape by using a material such as a fin material, a tube material, or a plate material as a heat exchanger. After the assembly, it can be applied to the heat exchanger, or can be applied in advance to a material such as a fin material, a tube material, or a plate material. In the former case, brazing heating is performed after the flux is applied to the heat exchanger, and in the latter case, each of the above materials is formed into a desired shape and assembled as a heat exchanger, and then brazing heating is performed. Do.

  When the flux is applied after being assembled as a heat exchanger, there are a method of sprinkling the flux powder, a method of spraying the flux powder by suspending it in water, and the like. When the material is coated in advance, the adhesion of the coating can be improved by mixing and applying a binder such as an acrylic resin to the flux powder.

Flux used to obtain the function of a normal flux, not as a brazing material component, includes KAlF ₄ , K ₂ AlF ₅ , K ₂ AlF ₅ .H ₂ O, K ₃ AlF ₆ , AlF ₃ , KZnF ₃ , K ₂ Fluoride flux such as SiF ₆ , cesium flux such as Cs ₃ AlF ₆ , CsAlF ₄ .2H ₂ O, Cs ₂ AlF ₅ .H ₂ O, and the like.

  Moreover, when apply | coating a brazing filler metal component to the surface of a tube material or a plate material, a brazing filler metal component and the said normal flux powder can also be mixed and apply | coated. Furthermore, if a binder such as an acrylic resin is mixed and applied, the adhesion of the coating can be improved.

Example 1
In this example, as examples and comparative examples according to the aluminum heat exchanger of the present invention, mini-cores of a plurality of types of aluminum heat exchangers were produced and their corrosion resistance was evaluated.
In this example, mini-cores (samples E1 to E26) of aluminum heat exchangers shown in Table 2 as examples, and mini-cores (samples C1 and C2) of aluminum heat exchangers shown in Table 2 as comparative examples. Was made.

A method for manufacturing a mini-core of an aluminum heat exchanger will be described with reference to FIG.
First, as the tube material 2, a JIS A 3003 alloy is used as a core material, an alloy obtained by adding 0.02% of Sr to a JIS A 4047 alloy (Al-12Si) is used as a brazing material (brazing material component), and a thickness of 0.25 mm. A clad material (10% clad rate) was prepared. In an aluminum alloy heat exchanger as an actual product, a brazing material 22 containing Si is disposed on the surface of the core material 21 by bending and welding the clad material to form a flat tube shape. A tube material having a clad structure is obtained. In addition, this plate-shaped thing is called the tube material 2 for convenience of explanation. The melting point (solidus temperature) of the brazing material is 570 ° C. or higher and 590 ° C. or lower.

Next, bare fin material 3 (fin 1 to fin 28) shown in Table 1 was produced.
For the fins 1 to 25, the fins 27, and the fins 28, ingots having the compositions shown in Table 1 were prepared by continuous casting, and then homogenized. Next, hot rolling is performed to a predetermined thickness, and then cold rolling, intermediate annealing, and cold rolling are performed to obtain a 0.1 mm thick plate (type H14), and the bare fin material 3 (fin 1 to fin 1). Fin 25, fin 27, and fin 28) were obtained.

Next, the fin 26 is prepared by continuous casting and rolling to prepare a sheet material having a thickness of 5 mm having the composition shown in Table 1, and thereafter performing cold rolling, intermediate annealing, and cold rolling to form a sheet material (quality: 0.10 mm). As another H14), the bare fin material 3 (fins 26) was obtained.
The composition hardly changes before and after the homogenization treatment, hot rolling, cold rolling, intermediate annealing, and cold rolling.

  From Table 1, the said fins 1-fin 26 are 1 type or 2 in Sr: 0.001-5.0%, Na: 0.001-5.0%, Sb: 0.001-5.0%. It turns out that it contains seeds or more and Mn: 0.1 to 3.0%.

Next, after the produced bare fin material 3 (fin 1 to fin 28) was cut into a belt having a predetermined width, corrugated molding was performed through a gear rotation type molding machine.
Thereafter, as shown in FIG. 1, the bare fin material 3 and the tube material 2 are assembled, and after applying a fluoride-based flux having a concentration of 3.0%, it is 600 ° C. in the nitrogen gas atmosphere (the brazing material component). The core 1 is heated at a temperature higher than the melting point of the fins 1 to 28 and lower than the melting point of the fins 1 to 28 (solidus temperature) for 3 minutes to perform brazing and joining. Sample E26, Sample C1, and Sample C2) were prepared.

Next, a corrosion test was performed on the manufactured mini-cores 8 (Sample E1 to Sample E26, Sample C1, and Sample C2) to evaluate the corrosion resistance. The results are shown in Table 2.
<Corrosion test>
In the corrosion test, the end surface and the core material surface of the mini-core 8 are masked with silicon resin, and then the SWAAT test is conducted for one month based on ASTM G85. The corrosion resistance was evaluated by observing. The corrosion resistance was judged to be good when the corrosion depth was 0.15 mm or less and the fin 3 was not dropped off, and when the corrosion depth exceeded 0.15 mm or the fin 3 was dropped off, it was judged as bad.

As is known from Table 2, Sample E1 to Sample E26 as examples all showed good corrosion resistance. Samples E1 to E26 showed high strength.
Thus, according to this invention, it turns out that the aluminum heat exchanger excellent in corrosion resistance and intensity | strength can be formed.
Further, as is known from Table 2, since the sample C1 and the sample C2 as comparative examples did not contain any of Sr, Na, and Sb, the corrosion resistance was poor.

  In this example, a tube material made of a clad material in which a JIS A 3003 alloy is used as a core material and an alloy obtained by adding 0.02% of Sr to JIS A 4047 alloy is used as a brazing material. The same effect can be obtained even when a general Al—Si brazing alloy or an Al—Si brazing alloy with Na or Sb added is used.

  In this example, the tube material made of the clad material was used. However, as the tube material, a brazing material powder such as Si powder or an aluminum alloy powder containing at least Si was applied to the surface of the tube material made of the extruded shape material. The same effect can be obtained also when using the one obtained by applying a flux that contains Si on the surface of a tube material made of an extruded profile and that contains a flux that generates a brazing material during brazing.

  In addition, when the tube material made of the clad material is coated with a flux mixed with a flux or a binder in advance, the surface of the tube material made of the extruded shape material is Si powder, or an aluminum alloy powder containing at least Si, etc. The same effect can be obtained when using a brazing material powder coated with flux powder or flux mixed with binder.

(Example 2)
In this example, a configuration example of an aluminum heat exchanger using the core portion (minicore) shown in the first embodiment will be described with reference to FIG. This example shows one embodiment, and the present invention is not limited to this, and various configurations known as an aluminum heat exchanger can be adopted.

As shown in FIG. 2, the aluminum heat exchanger 1 of this example has a core portion 4 including a tube 2 through which a working fluid flows and fins 3 joined to the outer surface of the tube 2.
The said core part 4 is comprised by brazing and joining the tube material 2 and the bare fin material 3 using the brazing material component containing Si.
The bare fin material 3 includes one or more of Sr: 0.001 to 5.0%, Na: 0.001 to 5.0%, Sb: 0.001 to 5.0%, and Mn: 0.1 to 3.0% is contained, and the balance consists of Al and inevitable impurities.

A method for manufacturing the aluminum heat exchanger 1 will be described.
First, as the tube material 2 constituting the core portion 4, in Example 1, the clad material produced as the tube material is bent and welded to form a flat tube shape, so that the surface of the core material will contain Si. A tube material 2 having a clad structure formed by arranging the materials is prepared.

  Next, as the bare fin material 3 constituting the core portion 4, an ingot containing Sr: 0.05% and Mn: 1.1% by continuous casting, with the balance being Al and inevitable impurities. After preparation and homogenization treatment, hot rolling is performed to a predetermined thickness, and then cold rolling, intermediate annealing, and cold rolling are performed to obtain a 0.1 mm-thick plate material (quality grade H14) And the bare fin material 3 is obtained. And after cutting a board | plate material into the strip | belt shape of predetermined width, corrugate shaping | molding is performed through a gear rotation type molding machine.

  Then, as shown in FIG. 2, the tube material 2 and the bare fin material 3 are assembled, headers are assembled to both ends of the tube 2, side plates 6 are assembled to the outermost fins 3 and the header 5, and a tank is attached to the header 5. 7 is applied, and a fluoride-based flux having a concentration of 3.0% is applied, and then in a nitrogen gas atmosphere at 600 ° C. (a temperature higher than the melting point of the brazing filler metal component and lower than the melting point of the bare fin material) for 3 minutes. It heats and braze-joins and the aluminum heat exchanger 1 is produced.

It should be noted that the configuration of the aluminum heat exchanger 1 other than the core portion 4 composed of the tube material 2 and the bare fin material 3 can be appropriately changed to a known configuration.
The aluminum heat exchanger 1 of this example has excellent corrosion resistance so that the fin 3 from the tube 2 does not drop off or early penetration corrosion of the tube 2 does not occur, as is known from Example 1 described above. Become.

Explanatory drawing which shows the minicore of the aluminum heat exchanger in Example 1. FIG. Explanatory drawing which shows the aluminum heat exchanger in Example 2. FIG. Explanatory drawing which shows the conventional bare fin material and tube material before brazing joining. Explanatory drawing which shows the conventional bare fin material and tube material after brazing joining. Explanatory drawing which shows dropping of the conventional bare fin material from the tube material. Explanatory drawing which shows the penetration corrosion of the conventional tube material.

Explanation of symbols

1 Aluminum heat exchanger 2 Tube (tube material)
3 Fin (Bare fin material)
4 Core part

Claims (10)

An aluminum heat exchanger having a core part composed of a tube through which a working fluid flows and fins joined to the outer surface of the tube,
The core part is configured by brazing and joining a tubular tube material and a bare fin material using a brazing material component containing Si,
The bare fin material is one or two of Sr: 0.01 to 1.0 % (mass%, hereinafter the same), Na: 0.01 to 0.02 %, Sb: 0.01 to 1.0 %. A heat exchanger made of aluminum containing at least seeds and Mn: 0.1 to 3.0%, the balance being made of Al and inevitable impurities.   In Claim 1, the said bare fin material is further 1 type or 2 in Zn: 0.1-5.0%, In: 0.001-0.3%, Sn: 0.001-0.3%. Aluminum heat exchanger characterized by containing more than seeds.   3. The bare fin material according to claim 1, wherein the bare fin material further includes Si: less than 3.0% (a range not exceeding the Mn content), Fe: less than 3.0% (a range not exceeding the Mn content). An aluminum heat exchanger comprising at least one.   The aluminum tube according to any one of claims 1 to 3, wherein the tube material is made of a clad material in which a brazing material containing the brazing material component is disposed on a surface of a core material by clad bonding. Heat exchanger.   5. The core part according to claim 1, further comprising a portion formed by brazing and joining the bare fin material and the plate-shaped plate material using a brazing filler metal component containing Si. An aluminum heat exchanger characterized by that. A method for producing an aluminum heat exchanger having a core portion comprising a tube through which a working fluid flows and fins joined to the outer surface of the tube,
Sr: 0.01 to 1.0 % (mass%, the same applies hereinafter), Na: 0.01 to 0.02 %, Sb: 0.01 to 1.0 %, one or more, and Mn : 0.1 to 3.0%, with the balance being a combination of a bare fin material composed of Al and unavoidable impurities and a tubular tube material with a brazing filler metal component containing Si, and then the brazing The tube material and the bare fin material are brazed and joined by heating at a temperature higher than the melting point (solidus temperature) of the material component and lower than the melting point (solidus temperature) of the bare fin material, and the core A method for producing an aluminum heat exchanger, characterized in that a part is formed.   7. The bare fin material according to claim 6, further comprising one or two of Zn: 0.1 to 5.0%, In: 0.001 to 0.3%, and Sn: 0.001 to 0.3%. The manufacturing method of the heat exchanger made from aluminum characterized by containing a seed | species or more.   8. The bare fin material according to claim 6, wherein the bare fin material further includes Si: less than 3.0% (a range not exceeding the Mn content), Fe: less than 3.0% (a range not exceeding the Mn content). A method for producing an aluminum heat exchanger, comprising at least one.   9. The aluminum tube according to claim 6, wherein the tube material is made of a clad material in which a brazing material containing the brazing material component is disposed on a surface of a core material by clad bonding. Manufacturing method of heat exchanger.   10. The core part according to claim 6, wherein the core portion is further brazed by heating after the bare fin and the plate-like plate material are combined with a brazing filler metal component containing Si. A method for producing an aluminum heat exchanger, wherein the aluminum heat exchanger is formed by bonding.

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