CN1726114A - Aluminum alloy brazing material, brazing member, brazed article and brazinh method therefor using said material, brazing heat exchanging tube, heat exchanger and manufacturing method thereof using sai - Google Patents

Abstract

A heat exchanger 10 includes a brazing heat exchanging tube S and a fin 4. The heat exchanging tube S and the fin 4 are brazed with each other via the brazing layer 11 of the heat exchanging tube S. The brazing layer 11 is formed by spraying of a brazing material consisting of Si: 6 to 15 mass%, Zn :1 to 20 mass%, at least one of Cu: 0.3 to 0.6 mass% and Mn: 0.3 to 1. 5 mass, and the balance being aluminum and inevitable impurities.

Description

Aluminum alloy brazing material, brazing piece, brazing product using said material and brazing method thereof, brazed heat exchange tube, heat exchanger using said brazed heat exchange tube, and manufacturing method thereof

This application claims the benefit of Japanese Patent Application No. 2002-361130, filed December 12, 2002, and U.S. Provisional Patent Application No. 60/451,262, filed March 4, 2003, the disclosures of which are hereby incorporated in their entirety Reference.

Cross References to Related Applications

This application is filed pursuant to 35 U.S.C. §111(a) and required by 35 U.S.C. §119(e)(1) of U.S. Provisional Patent Application No. filed on March 4, 2003 under 35 U.S.C. §111(b). Priority of 60/451,262.

technical field

The invention relates to an aluminum alloy (hard) brazing material, a brazing piece, a brazing product using the brazing piece and a manufacturing method thereof. The present invention also relates to a heat exchange tube, a heat exchanger using the heat exchange tube and a method of manufacturing the heat exchanger, the heat exchange tube needs to have corrosion resistance in order to be used, for example, in automobiles, household or commercial air conditioners Used in aluminum or aluminum alloy heat exchangers for radiators, condensers and evaporators in equipment.

Background technique

As is known, heat exchangers with heat exchange cores in which aluminum flat heat exchange tubes and corrugated fins are alternately arranged and brazed to each other can be used in condensers or evaporators for automotive radiators and coolers. welded together.

In the manufacture of such heat exchangers, well-known techniques are to prevent corrosion of heat exchange tubes by preferential corrosion of fillet welds, or to form a zinc (Zn) diffusion layer on the surface layer of heat exchange tubes, thereby passing through the surface layer Partial sacrificial corrosion to improve corrosion of heat exchangers. According to a known method, for example, a molten Al-Si-Zn series alloy brazing material is sprayed onto the surface of the heat exchange tube to form a brazing layer, and then the fins are brazed to the brazing layer using the brazing layer. heat exchange tubes, thereby connecting the fins and forming a zinc diffusion layer (see, for example, Table 4 in Japanese Patent Laid-Open No. S59-10467 and lines 9 to 12 in the lower left column on page 3, claim 1 of Japanese Patent No. 2515561, etc., and claim 1 of Japanese Patent Laid-Open No. H7-174482, etc.).

For oil cooler tubes, Al-Si-Cu-Zn series alloys are sometimes used as low-melting-point brazing materials (for example, claim 3 of Japanese Patent Laid-Open No. H10-265881, etc.).

In the case of a heat exchange tube sprayed with the above-mentioned Al-Si-Zn series alloy brazing material containing a large amount of Zn or a heat exchange tube sprayed with Zn, although fin separation occurs due to preferential corrosion of fillet welds, as long as It is considered that the corrosion resistance of the entire heat exchanger can be improved by delaying the separation time of the fins. In addition, existing heat exchangers have a large corrosion depth due to the Zn diffusion layer. Therefore, in the case of heat exchange tubes having a relatively small thickness available recently, it is difficult to secure a sufficient effective thickness.

In addition, when using the above-mentioned Al-Si-Cu-Zn series alloy brazing material disclosed by Japanese Patent Application No. H10-265881, due to the large amount of Cu (0.7 to 0.8% by mass) causes intergranular corrosion to occur, so there is a problem in corrosion resistance.

Even if intergranular corrosion does not occur, adding more than 0.7% by mass of Cu to the brazing material will impair its own corrosion resistance and be accompanied by pitting corrosion. Therefore, this brazing material is not suitable for the above-mentioned thin tubes.

The above-mentioned problems also arise when brazing products other than those of heat exchangers.

Contents of the invention

In view of the above technical background, the present invention aims to provide an aluminum alloy brazing material as an anti-corrosion brazing material due to sacrificial corrosion because it can suppress the separation of the brazing parts and reduce the depth of corrosion. Brazing material of brazing material, a brazing product using the brazing part, a method of manufacturing the brazing product, a brazed heat exchange tube, a heat exchanger using the heat exchange tube, and A method of manufacturing the heat exchanger.

The aluminum alloy brazing material according to the present invention is defined by the following items (1) to (5):

(1) An aluminum alloy brazing material, mainly comprising:

Si: 6-15% by mass;

Zn: 1-20% by mass;

At least one of 0.3-0.6% by mass of Cu and 0.3-1.5% by mass of Mn; and

The rest is Al and impurities.

(2) The aluminum alloy brazing material as described in the above item (1), wherein the content of Si is 6-12.5% by mass.

(3) The aluminum alloy brazing material as described in the above item (1) or (2), wherein the content of Zn is 2 to 7% by mass.

(4) The aluminum alloy brazing material as described in any one of the above items (1) to (3), wherein the content of Cu is 0.4 to 0.55% by mass.

(5) The aluminum alloy brazing material as described in any one of the above items (1) to (4), wherein the content of Mn is 0.4 to 1% by mass.

The brazing part, the brazing article and the method of manufacturing the brazing article according to the present invention are defined by the following items (6) to (9):

(6) A brazing piece comprising an aluminum or aluminum alloy base material and a brazing layer formed on the surface of the base material, wherein the brazing layer is defined by any one of the aforementioned items (1) to (5). A sprayed layer of defined aluminum alloy brazing material.

(7) A brazing product, comprising:

Brazing parts as defined in item (6) above; and

a joint,

Wherein, the brazing part and the joining part are brazed together through the brazing layer of the brazing part.

(8) A method of manufacturing a brazing product, comprising the following steps:

A brazing part is prepared by spraying the aluminum alloy brazing material defined in any one of the aforementioned items (1) to (5) onto the surface of an aluminum or aluminum alloy substrate to form a brazing layer; and

The brazing part and the other joining part are heated in combination to braze the brazing part and the joining part together through the brazing layer.

(9) The method for producing a brazed product as described in the aforementioned item (8), wherein the brazing step is performed under normal pressure.

The brazed heat exchange tube according to the present invention is defined by the following items (10) to (15):

(10) A brazed heat exchange tube, comprising:

An aluminum or aluminum alloy heat exchange tube substrate; and

a brazing layer formed on the surface of the heat exchange tube substrate,

Wherein, the brazing layer is a sprayed layer of the aluminum alloy brazing material defined in any one of the aforementioned items (1) to (5).

(11) The brazed heat exchange tube as described in the aforementioned item (10), wherein the heat exchange tube base material is made of a JIS A1000 series alloy.

(12) The brazed heat exchange tube as described in the aforementioned item (10), wherein the heat exchange tube base material is made of a JIS A3003 series alloy.

(13) The brazed heat exchange tube as described in the aforementioned item (10), wherein the heat exchange tube base material is made of Al containing more than 0.2% by mass but not more than 0.6% by mass of Cu and 0.15 to 2% by mass of Mn -Cu-Mn series alloys.

(14) The brazed heat exchange tube as described in item (13) above, in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.15-0.4% by mass.

(15) The brazed heat exchange tube as described in item (13) above, in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.6-1.5% by mass.

The heat exchanger according to the present invention is defined by the following items (16) to (22):

(16) A heat exchanger comprising:

The brazed heat exchange tube defined by the aforementioned item (10); and

fins,

Wherein, the heat exchange tube and the fin are brazed together through the brazing layer of the heat exchange tube.

(17) The heat exchanger as described in the aforementioned item (16), wherein the heat exchange tube base material of the brazed heat exchange tube is a JIS A1000 series alloy.

(18) The heat exchanger as described in the aforementioned item (16), wherein the heat exchange tube base material of the brazed heat exchange tube is a JIS A3003 series alloy.

(19) The heat exchanger as described in the aforementioned item (16), wherein the heat exchange tube base material of the brazed heat exchange tube is composed of more than 0.2 mass % but not more than 0.6 mass % of Cu and 0.15 to 2 mass % Made of Mn Al-Cu-Mn series alloys.

(20) The heat exchanger as described in the aforementioned item (19), wherein in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.15-0.4% by mass.

(21) The heat exchanger as described in the aforementioned item (19), wherein in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.6-1.5% by mass.

(22) The heat exchanger as described in any one of the aforementioned items (16) to (21), wherein the fins are made of a JIS A3000 series alloy.

The heat exchanger manufacturing method according to the present invention is defined by the following items (23) to (25):

(23) A method of manufacturing a heat exchanger, comprising the steps of:

Brazing heat exchange tubes are produced by spraying the aluminum alloy brazing material defined in any one of the preceding items (1) to (5) onto the surface of an aluminum or aluminum alloy heat exchange tube base material to form a brazing layer; and

The brazed heat exchange tubes and the fins are heated in combination to braze the brazed heat exchange tubes and the fins together with the brazing layer of the brazed heat exchange tubes.

(24) The heat exchanger manufacturing method as described in the aforementioned item (23), wherein the step of preparing the brazed heat exchange tube is carried out by forming the heat exchange tube base material by extrusion, and then applying the aluminum alloy brazing material Spray onto the heat exchange tube substrate.

(25) The heat exchanger manufacturing method as described in the aforementioned item (23) or (24), wherein the brazing step is performed under normal pressure.

According to the present invention described in the aforementioned item (1), Cu and Mn raise the potential of the fillet weld to reduce the potential difference between the fillet weld and the joint, thereby preventing excessive corrosion of the fillet weld, and utilizing the Zn in this joint sacrificially corrodes the corrosion layer to reduce corrosion depth. This makes it possible to reduce the predetermined thickness of the joining member necessary to prevent pitting corrosion, thereby improving the corrosion resistance of the aluminum alloy brazing material while reducing the weight of the brazed product.

According to the present invention described in the aforementioned item (2), an aluminum alloy brazing material having particularly good brazing performance can be obtained.

According to the present invention described in the aforementioned item (3), a kind of aluminum alloy brazing material with particularly good corrosion resistance capable of forming a suitable Zn diffusion layer can be obtained

According to the present invention described in the aforementioned item (4), there can be obtained an aluminum alloy brazing material that is particularly excellent in corrosion resistance and capable of suppressing excessive corrosion.

According to the present invention described in the aforementioned item (5), there can be obtained an aluminum alloy brazing material that is particularly excellent in corrosion resistance and capable of suppressing excessive corrosion.

According to the present invention described in the aforementioned item (6), Cu and Mn raise the potential of the fillet weld to reduce the potential difference between the fillet weld and the joint, thereby preventing excessive corrosion of the fillet weld, and utilizing the The Zn in the joining piece sacrifices the corrosion layer to reduce the corrosion depth, thereby obtaining an aluminum alloy brazing piece with very good corrosion resistance.

According to the invention recited in the aforementioned item (7), the brazing member and another joining member can be suitably joined together, thereby obtaining a brazed product excellent in corrosion resistance.

According to the invention recited in the aforementioned item (8), the brazing member and another joining member can be suitably joined together, thereby obtaining a brazed product excellent in corrosion resistance.

According to the present invention described in the aforementioned item (9), a Zn sacrificial etching layer can be appropriately formed on the surface portion of the base material.

According to the present invention described in the aforementioned item (10), Cu and Mn raise the potential of the fillet weld to reduce the potential difference between the fillet weld and the joint, thereby preventing excessive corrosion of the fillet weld, and utilizing the Zn in this joint sacrificially corrodes the corrosion layer to reduce corrosion depth. This reduces the thickness of the heat exchange tube, resulting in a brazed heat exchange tube that is light in weight and very resistant to corrosion.

According to the present invention described in the aforementioned item (11), there can be obtained a brazed heat exchange tube particularly excellent in corrosion resistance.

According to the present invention described in the aforementioned item (12), a brazed heat exchange tube particularly excellent in corrosion resistance can be obtained.

According to the present invention described in the aforementioned item (13), there can be obtained a brazed heat exchange tube particularly excellent in corrosion resistance.

According to the present invention described in the aforementioned item (14), a brazed heat exchange tube particularly excellent in corrosion resistance and extrudability can be obtained.

According to the present invention described in the aforementioned item (15), there can be obtained a brazed heat exchange tube which is particularly excellent in corrosion resistance and high-temperature strength.

According to the present invention recited in the aforementioned item (16), there can be obtained a heat exchanger excellent in corrosion resistance in which brazed heat exchange tubes and fins are preferably bonded together.

According to the present invention described in the aforementioned item (17), a heat exchanger particularly excellent in corrosion resistance can be obtained.

According to the present invention described in the aforementioned item (18), a heat exchanger particularly excellent in corrosion resistance can be obtained.

According to the present invention described in the aforementioned item (19), a heat exchanger particularly excellent in corrosion resistance can be obtained.

According to the present invention described in the aforementioned item (20), a heat exchanger particularly excellent in corrosion resistance can be obtained. In addition, the manufacturing efficiency and shape accuracy of the exchange tube can be improved, resulting in very good manufacturing efficiency and shape accuracy.

According to the present invention described in the aforementioned item (21), a heat exchanger excellent in corrosion resistance and high-temperature strength can be obtained.

According to the present invention recited in the aforementioned item (22), it is possible to manufacture a heat exchanger excellent in corrosion resistance in which brazed heat exchange tubes and fins are preferably bonded together.

According to the present invention recited in the aforementioned item (23), there can be obtained a heat exchanger excellent in corrosion resistance in which brazed heat exchange tubes and fins are preferably bonded together.

According to the present invention recited in the aforementioned item (24), in the step of preparing the brazed heat exchange tube, it is possible to efficiently produce a brazed material having excellent adhesion between the heat exchange tube base material and the brazing layer. The heat exchange tubes, in turn, make it possible to manufacture heat exchangers that are very resistant to corrosion.

According to the invention described in the aforementioned item (25), a Zn sacrificial corrosion layer can be formed in the surface portion of the heat exchange tube in a preferred manner.

Description of drawings

1 is a front view showing a heat exchanger according to an embodiment of the present invention;

Fig. 2 is a perspective view showing a partial main part of a core portion of a heat exchanger;

3 is a schematic cross-sectional view showing a connected state of tubes and fins of a heat exchanger;

Figure 4 is a graph showing corrosion potential in a heat exchanger;

Fig. 5 is a schematic diagram showing a method of manufacturing a brazing member according to the present invention.

Detailed ways

The aluminum alloy brazing material according to the present invention is used to manufacture various brazing parts or brazing products, so as to finally improve the corrosion resistance of the brazing products. Therefore, an aluminum alloy brazing material and a brazing product according to the present invention will be described below.

To be brazed with fins for use in aluminum or aluminum alloy heat exchangers such as condensers or evaporators in automobiles, domestic or commercial air-conditioning units, or heat exchange tubes for radiators can be used as the above-mentioned brazing parts example. In the following description, "brazing parts or brazed heat exchange tubes", "substrates or heat exchange tube base materials", and "brazed products or heat exchangers" will be abbreviated as "brazing parts, etc.", respectively, "Substrates, etc.", "Brazing products, etc." The following description is mainly for the case where the brazed part is a brazed heat exchange tube and the brazed product is a heat exchanger. However, it should be understood that the brazing parts and brazing articles are not limited thereto in the present invention.

In the brazing member or the like according to the present invention, the aluminum alloy brazing material according to the present invention is sprayed onto the surface of a base material or the like so that the base material or the like has a layer of the brazing material required for joining. A brazing product or the like can be manufactured using the brazing material or the like.

The above-mentioned brazing fittings and the like will be described with reference to the drawings by taking, as an example, the heat exchange tube 3 which is a constituent part of the heat exchanger shown in FIGS. 1 and 2 .

In this heat exchanger, fins 4 are brazed to opposite outer planes of heat exchange tubes 3 . A brazed heat exchange tube S according to the present invention in which a sprayed brazing layer 11 is formed on the outer surface of a heat exchange tube base material 30 is used as the heat exchange tube 3 . 3 is a schematic sectional view showing a joined state in which the brazed heat exchange tube S and the fin 4 are brazed together to form a fillet 12 . Reference numeral 13 denotes a Zn diffusion layer.

The brazing layer 11 is made of an aluminum alloy brazing material according to the present invention, and the composition of the brazing material includes 6-15% by mass of Si, 1-20% by mass of Zn, 0.3-0.6% by mass of Cu and 0.3- 1.5% by mass of at least one of Mn and the rest of Al and impurities.

In the above-mentioned aluminum alloy brazing material, Si lowers the melting point of the alloy to be used as a joining metal. If the Si content is less than 6% by mass or greater than 15% by mass, brazing performance is impaired. Therefore, the Si content should be in the range of 6-15% by mass. The content of Si is preferably 6-12.5% by mass.

Zn thermally diffuses into the surface layer portion of the heat exchange tube base material 30 of the heat exchange tube 3 by brazing to form the Zn diffusion layer 13, which improves the corrosion resistance of the heat exchange tube 3 after brazing. If the content of Zn is less than 1% by mass, the absolute amount of Zn is insufficient, resulting in insufficient anti-corrosion effect. Whereas, if the content of Zn exceeds 20% by mass, the corrosion resistance of the fillet weld 12 formed by brazing heat is impaired, resulting in separation from the fin 4 to be bonded to another joining member such as the heat exchange tube 3 . Therefore, the content of Zn should be in the range of 1-20% by mass. The content of Zn is preferably 2-7% by mass.

Cu and Mn are elements that increase the corrosion potential of the brazing material. As shown in Fig. 4, in a conventional heat exchanger using a brazing material that does not contain these elements, the fillet weld is easily corroded because the corrosion potential E2 of the fillet weld is lower than that of the fins, thereby easily Separate the fins. On the contrary, in the present invention, the corrosion potential E1 of the fillet weld 12 is shifted to a higher corrosion potential by adding Cu and Mn, so that the corrosion potential of the fillet weld 12 is close to the corrosion potential of the fin 4, thereby suppressing the corrosion potential of the fillet weld 12. Excessive corrosion of the slots 12, in turn, prevents the fins 4 from separating. This also has the effect of reducing the etch depth by sacrificial etching. To achieve the above effects, it is sufficient to add only Cu or Mn, but Cu and Mn may be added simultaneously. If the content of Cu is less than 0.3% by mass, the above-mentioned effects are insufficient. On the contrary, if the content of Cu exceeds 0.6% by mass, intergranular corrosion occurs, which impairs corrosion resistance. Therefore, the content of Cu should be in the range of 0.3-0.6 mass%. The content of Cu is preferably 0.4-0.55% by mass. In addition, if the content of Mn is less than 0.3% by mass, the above-mentioned effects are insufficient. On the contrary, if the content of Mn exceeds 1.5% by mass, huge intermetallic compounds will be generated, which will impair the corrosion resistance. Therefore, the content of Mn should be in the range of 0.3-1.5% by mass. The content of Mn is preferably 0.4-1% by mass.

Al is contained in the brazing material as a matrix. Brazing materials may contain any impurities in such amounts that they do not impair brazing performance. For example, such impurities include Fe, In, Sn, Ni, Ti and Cr.

The aluminum alloy brazing material according to the invention may take any configuration, for example may be manufactured as ingots, extrusions, drawings, rolled sheets, foils or powders.

The aluminum or aluminum alloy material constituting the heat exchange tube base material 30 is not limited to a specific one, but may be any aluminum or aluminum alloy. Preferably, a JIS (Japanese Industrial Standard) A1000 series alloy, a JIS A3003 alloy (with a Cu content of 0.05-0.2% by mass and a Mn content of 1-1.5% by mass) can be used as such aluminum or aluminum alloy. Preferably, Al-Cu-Mn series alloys containing more Cu and Mn than JIS A3003 alloys can also be used. It is recommended to use a tube made of one of the alloys mentioned above.

Among the JIS A1000 series alloys among the above three alloys, the JIS A1100 alloy is particularly recommended, which has been widely used as a pipe material.

The following are the reasons why JIS A3003 or Al-Cu-Mn series alloys are recommended. Using the heat exchange tube base material 30 containing Cu and Mn, Cu and Mn will diffuse into the fillet weld 12 to increase the corrosion potential, thereby improving the corrosion resistance of the fillet weld 12 . This effect can be achieved or improved even if the Cu content and the Mn content exceed those in the JIS A3003 alloy. Therefore, in the brazed heat exchange tube S according to the present invention, JIS A3003 and an Al-Cu-Mn series alloy containing more Cu and Mn are recommended as the material of the heat exchange tube base material 30 .

The above-mentioned Al-Cu-Mn series alloy contains more than 0.2 mass % but not more than 0.6 mass % of Cu and 0.15-2 mass % of Mn. If the content of Cu exceeds 0.6% by mass, intergranular corrosion tends to occur in the tube 3 . Therefore, the upper limit of the Cu content should be 0.6% by mass. In addition, if the content of Mn exceeds 2% by mass, large intermetallic compounds are generated to impair formability. Therefore, the upper limit of the Mn content should be 2% by mass.

In the composition of the above-mentioned Al-Cu-Mn series alloy, it is preferable that the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.15-0.4% by mass. If the Cu content and the Mn content fall within the respective ranges described above, the fillet weld potential can be made high, and extrusion processability can be improved. Therefore, when a tube is produced by extrusion, production efficiency can be improved and a tube with very good molding accuracy can be obtained.

In the composition of the above-mentioned Al-Cu-Mn series alloy, it is also preferable that the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.6-1.5% by mass. If the Cu content and the Mn content fall within the above respective ranges, the potential of the fillet weld can be made high, and very good high-temperature strength can be obtained. This improves the durability of the heat exchange tubes, which in turn increases the durability of the heat exchanger.

The remaining components of Al-Cu-Mn series alloys are Al and impurities. However, the remaining components may include other elements as long as the above-mentioned effects are not inhibited.

The aluminum or aluminum alloy constituting the fin 4 is not limited to a specific one alloy, but various aluminum or aluminum alloys may be used. It is preferable that the fins 4 are made of JIS A3000 series alloy (Al-Mn series alloy). An example of such an alloy is an alloy having an Al—Mn content of 1.2 mass % and a Zn content of 1 mass %.

In the brazed heat exchange tube S, the brazing layer 11 is formed by a thermal spray method. The brazing layer 11 does not have to be formed on the entire outer surface of the heat exchange tube base material 30, but only on the portion to be brazed. Even if the brazing layer is not formed on the entire outer surface, the molten brazing material flows around the entire outer surface to form a uniform Zn diffusion layer.

A well-known device can be used to perform the thermal spraying method. FIG. 5 shows an example of this method: that is, a heat spray gun 21 is provided on the exit side of an extruder 20 for extruding a heat exchange tube base material 30 having a predetermined cross section, so that the heat exchange tube base material 30 is continuously processed. The material 30 is shaped and the brazing layer 11 is formed on the heat exchange tube base material 30 . By this method, the brazed heat exchange tube S can be manufactured efficiently. Furthermore, since the heat exchange tube base material 30 is thermally sprayed immediately after it is extruded—that is, before the heat exchange tube base material 30 is cooled—the adhesiveness of the brazing layer 11 is very good. The aluminum alloy brazing material to be sprayed can be arbitrarily selected from various materials including rod-like materials and powder-like materials suitable for thermal spraying devices.

Next, a method of manufacturing the parallel flow heat exchanger shown in FIGS. 1 and 2, which is an example of a brazed product, will be described.

In Fig. 1, reference numerals "1" and "2" designate headers, "3" designate aluminum or aluminum alloy heat exchange tubes, "4" designate corrugated fins, "5" designate inlets for heat exchange medium, "6" " indicates the outlet of the heat exchange medium, "8" and "9" indicate the side plates, and "10" indicates the core of the heat exchanger.

As shown in FIG. 2 , a plurality of brazed heat exchange tubes S in which the brazed layer 11 is formed on the outer surface of the heat exchange tube base material 30 are prepared. Then, the opposite ends of the heat exchange tubes S are inserted into corresponding tube insertion holes formed in the headers 1 and 2 at intervals along the longitudinal direction of the headers 1 and 2 . Then, corrugated fins 4 are installed into the spaces between adjacent heat exchange tubes S and S to form a heat exchanger assembly having a heat exchange core 10 .

Thereafter, if necessary, the heat exchanger assembly is heated after applying the flux to the heat exchanger assembly. This heating melts the brazing layer 11, thereby forming a fillet weld 12 between the heat exchange tube base material 30 and the corrugated fins 4, thereby allowing the components 30 and 4 to be very well brazed together. In the manufactured heat exchanger core 10 , since the corrosion potential of the fillet weld 12 is close to the corrosion potential of the fin 4 , separation of the fin 4 due to preferential corrosion of the fillet weld 12 can be suppressed. In addition, Zn uniformly diffuses into the surface layer portion of the heat exchange tube base material 30 during brazing, thereby forming a Zn diffusion layer 13, which improves the corrosion resistance of the heat exchange tube 3, thereby improving the overall heat exchanger performance. corrosion resistance.

Brazing can be performed under normal conditions. Brazing at atmospheric pressure is recommended. However, vacuum brazing evaporates Zn contained in the brazing layer 11 . Therefore, vacuum brazing will make the Zn diffusion layer insufficient, resulting in poor corrosion resistance.

example

Brazed heat exchange tubes in which brazing material layers were formed on three kinds of heat exchange tube base materials were produced. These brazed heat exchange tubes and fins were assembled into a heat exchange core and then brazed to each other to obtain a brazed product for evaluation. A JIS A1100 alloy was used as the material of the heat exchange tube base material in Manufacturing Example 1 below, a JIS A3003 alloy was used as the material of the heat exchange tube base material in Manufacturing Example 2 below, and polycarbonate was used in Manufacturing Example 3 below. An Al-Cu-Mn series alloy is used as the material for the base material of the heat exchange tube.

[Manufacturing example 1]

Brazed heat exchange tubes numbered 1 to 28 shown in Table 1 were fabricated.

Various aluminum alloy brazing materials shown in Table 1 and Zn were used as the bar spray material for forming the brazing material layer. The content of Zn contained in the aluminum alloy brazing material will be reduced by spraying the brazing material. Therefore, in the column of the brazing material layer composition in Table 1, the composition of each strip-shaped spray material is not shown but the composition of each brazing material formed by spraying, that is, each to be used for brazing Composition of aluminum alloy brazing layer. The remaining components of each aluminum alloy brazing material are aluminum and impurities.

Each brazed heat exchange tube was produced using the extruder 20 and the heat spray guns 21 and 21 of the arc spray equipment provided on the exit side of the extruder 20 . First, a flat-shaped porous tube 30 having a height of 3 mm, a width of 16 mm, and a wall thickness of 0.5 mm was extruded in the extruder 20 (see FIG. 2 ). Then, the bar-shaped spray material is sprayed onto the flat outer surface of the porous tube 30 from the thermal spray guns 21 and 21 immediately after extrusion to form the brazing material layer 11 on the entire outer surface of the porous tube 30, and then the The perforated tube is cooled with water and wound into a coil 22 . In this way, long and continuous brazed heat exchange tubes S can be manufactured through the above steps. The injection amount for each of the brazed heat exchange tubes numbered 1 to 27 was 50 g/m ² . The injection amount of the Zn injection pipe No. 28 is 10 g/m ² .

Then, this long and continuous brazed heat exchange tube S was cut into pieces each having a length of 250 mm to manufacture a number of brazed heat exchange tubes S shown in FIG. 2 , and then the following brazing test was performed.

(brazing test)

The brazed heat exchange tube S and the fins 4 made of an alloy with an Al-Mn content of 1.2% by mass and a Zn content of 1% by mass were used to produce a multi-flow heat exchanger core. Then, the heat exchanger core was immersed in a flux liquid in which a fluoride series flux was suspended in water, and then dried. Thereafter, heat at 600 °C for 10 min under _N2 gas shielding gas at atmospheric pressure.

The brazing properties of the obtained brazed articles were evaluated using the following reference symbols.

(brazing performance)

◎: No corrosion, fin-heat exchange tube joint rate not less than 95%

○: Mildly corroded, fin-heat exchange tube joint rate not less than 95%

△: Mildly corroded, the fin-heat exchange tube joint rate is not less than 80% but less than 95%

×: Severe corrosion, fin-heat exchange tube joint ratio is less than 80%

These results are also shown in Table 1.

In addition, a CCT corrosion test (Combined Cycle Corrosion Test) and a SWATT corrosion test were performed on each brazed product under the following conditions. Then, the corrosion resistance was evaluated based on the fin separation state and the corrosion depth (μm) of the heat exchange tubes using the following symbols. Specimens Nos. 26 and 27 were poorly brazed and therefore were not subjected to corrosion testing.

(CCT corrosion test)

A 5% NaCl aqueous solution was used as the corrosion test liquid.

The cycle of spraying the corrosion test liquid for 1 hour→drying for 2 hours→wetting for 21 hours was repeated 180 times.

(SWATT corrosion test)

A mixed solution (pH 2.8 to 3) of artificial seawater and acetic acid according to the ASTM (American Society for Testing and Materials) standard was used as the etching solution.

The cycle of spraying the corrosion test liquid for 0.5 hours→drying for 1.5 hours was repeated for 960 hours.

(Fin separation state)

◎: After the SWATT test, the fin retention rate is 90% or more

○: After the SWATT test, the fin retention rate is 60% or more but less than 90%

Δ: After the SWATT test, the fin retention rate is 30% or more but less than 60%

×: After the SWATT test, the fin retention rate is less than 30%

(corrosion depth)

After the CCT corrosion test and the SWATT corrosion test, the corrosion depth (μm) of the opposite plane of the heat exchange tube was measured. In each corrosion test, nine sections of 250 mm long heat exchange tubes were used, and the maximum corrosion depth was taken as the corrosion depth for each test.

These results are also shown in Table 1.

Table 1 serial number Brazing layer composition (mass%) and the rest: Al and impurities Brazing performance CCT corrosion test SWAAT corrosion test Si Zn Cu mn fin separation state Corrosion depth (μm) fin separation state Corrosion depth (μm) example 1 6 4 0.5 - ◎ ◎ 104 ◎ 88 2 6 6 0.5 - ◎ ◎ 108 ◎ 97 3 7.5 3 0.5 - ◎ ◎ 100 ◎ 80 4 7.5 15 0.5 - ◎ ◎ 109 ○ 98 5 10 3 0.5 - ◎ ◎ 101 ◎ 82 6 10 6 0.6 - ◎ ◎ 107 ◎ 94 7 12 3 0.5 - ◎ ◎ 102 ◎ 85 8 12 6 0.4 - ◎ ◎ 108 ◎ 96 9 6 4 - 0.5 ◎ ◎ 105 ◎ 90 10 6 6 - 0.5 ◎ ◎ 107 ◎ 94 11 7.5 3 - 0.5 ◎ ◎ 100 ◎ 81 12 7.5 15 - 0.8 ◎ ◎ 109 ○ 98 13 10 3 - 0.4 ◎ ◎ 102 ◎ 84 14 10 6 - 1.2 ◎ ◎ 106 ◎ 92 15 12 3 - 0.5 ◎ ◎ 101 ◎ 82 16 12 6 - 0.9 ◎ ◎ 104 ◎ 88 17 7.5 3 0.5 0.5 ◎ ◎ 100 ◎ 80 18 10 6 0.4 0.9 ◎ ◎ 105 ◎ 90 comparison example 19 7.5 3 - - ◎ ◎ 135 ○ 123 20 7.5 3 0.8 - ◎ ◎ 170 ○ 160 twenty one 7.5 3 - 1.7 ◎ ◎ 136 ○ 124 twenty two 7.5 3 0.1 - ◎ ◎ 132 ○ 120 twenty three 7.5 3 - 0.1 ◎ ◎ 134 ○ 121 twenty four 7.5 60 - - ◎ ○ 140 x 138 25 7.5 0.5 - - ◎ ○ 160 ○ 150 26 20 4 - - x - - - - 27 4 4 - - x - - - - 28 Zn injection pipe (10g/m ² ) ◎ ○ 148 △ 102

The results shown in Table 1 show that the corrosion resistance of the brazed articles of each example using the predetermined aluminum alloy is very good.

[Manufacturing example 2]

A JIS A3003 alloy having the composition shown in Table 2 was used as the material of the heat exchange tube base material. The flat porous extruded tube 30 was formed using the same method as in Manufacturing Example 1, and then the bar-shaped spray material was sprayed onto the opposite planes of the porous tube immediately after extrusion to form the brazing material layer 11 . Thereafter, the porous tube is cooled with water and then wound into a roll 22 . In this way, long and continuous brazed heat exchange tubes S can be manufactured through the above steps. Each composition of the brazing material layer 11 formed by this spraying method is indicated by numerals 31 to 38, respectively. The injection amount in each brazed heat exchange tube was 50 g/m ² .

Table 2 A3003 composition (mass%), the rest: Al and impurities Si Fe Cu mn Mg Cr Zn Ti 0.1 0.37 0.1 1 - - - 0.01

Next, in the same manner as in Manufacturing Example 1, 250 mm long brazed heat exchange tubes S and fins 4 were manufactured as a heat exchanger core and brazed together under the same conditions.

The brazing performance of each of the obtained brazed articles was evaluated using the same reference symbols.

In addition, each brazed product was subjected to a CCT corrosion test (combined cycle corrosion test) and a SWAAT corrosion test in the same manner as in Production Example 1. Then, the fin separation state and the tube corrosion depth (µm) were evaluated.

These results are shown in Table 3.

table 3 serial number Brazing layer composition (mass%) and the rest: Al and impurities Brazing performance CCT corrosion test SWAAT corrosion test Si Zn Cu mn fin separation state Corrosion depth (μm) fin separation state Corrosion depth (μm) example 31 7.5 10 - 1 ◎ ◎ 102 ◎ 90 32 10 6 0.35 - ◎ ◎ 97 ◎ 87 33 10 0.35 - ◎ ◎ 101 ◎ 88 34 5 - ◎ ◎ 100 ◎ 87 35 15 0.35 - ◎ ◎ 102 ◎ 89 36 0.5 - ◎ ◎ 100 ◎ 87 37 12 10 0.4 - ◎ ◎ 99 ◎ 86 38 15 0.4 - ◎ ◎ 101 ◎ 90

The results shown in Table 3 show that the corrosion resistance of each example brazed article is very good.

[Manufacturing example 3]

Al—Cu—Mn alloys Nos. 41 to 49 having the compositions shown in Table 4 were used as the material of the heat exchange tubes. The flat porous extruded tube 30 was formed by the same method as in Manufacturing Example 1, and then the bar-shaped spray material was sprayed onto the opposite planes of the porous tube immediately after extrusion to form the brazing material layer 11 . Thereafter, the porous tube is cooled with water and wound into a roll 22 . In this way, long and continuous brazed heat exchange tubes S are produced through the above steps. In each example, using the same strip-shaped spray material, the composition of the brazing material layer 11 formed by the spray method is: 10% by mass of Si, 5% by mass of Zn, 0.4% by mass of Cu, and the rest being Al and Impurities. The injection amount in each brazed heat exchange tube was 50 g/m ² .

Next, in the same manner as in Manufacturing Example 1, 250 mm long brazed heat exchange tubes S and fins 4 were manufactured as a heat exchanger core and brazed together under the same conditions.

The brazing performance of each of the obtained brazed articles was evaluated using the same reference symbols.

In addition, each brazed product was subjected to a CCT corrosion test (combined cycle corrosion test) and a SWAAT corrosion test in the same manner as in Production Example 1. Then, the fin separation state and the tube corrosion depth (µm) were evaluated.

These results are shown in Table 4.

Table 4 serial number Composition of tube (mass%) Rest: Al and impurities Brazing performance CCT corrosion test SWAAT corrosion test Cu mn fin separation state Corrosion depth (μm) fin separation state Corrosion depth (μm) example 41 0.21 0.15 ◎ ◎ 105 ◎ 87 42 2 ◎ ◎ 104 ◎ 85 43 0.25 0.2 ◎ ◎ 105 ◎ 85 44 1 ◎ ◎ 104 ◎ 84 45 0.3 1.5 ◎ ◎ 103 ◎ 83 46 0.4 0.2 ◎ ◎ 103 ◎ 82 47 1 ◎ ◎ 102 ◎ 80 48 0.6 0.15 ◎ ◎ 100 ◎ 80 49 2 ◎ ◎ 98 ◎ 79

Brazing material layer: 10% by mass of Si, 5% by mass of Zn, 0.4% by mass of Cu, the remainder being Al and impurities

The results shown in Table 4 show that the corrosion resistance of each example brazed article is very good.

The terms and expressions used herein are for the purpose of description rather than limitation, and when using these terms and expressions, it does not exclude any solution equivalent to the features or parts described and shown, and may be used within the scope of the claims of the present invention. Make various modifications.

Industrial Applicability

The aluminum alloy brazing material according to the present invention can limit the corrosion depth by sacrificial corrosion when it is used as a corrosion-resistant material for brazing, so it can be used when manufacturing aluminum brazing products such as heat exchangers that require corrosion resistance. The aluminum alloy brazing material of the present invention.

Claims (25)

1. An aluminum alloy brazing material, mainly comprising: Si: 6-15% by mass; Zn: 1-20% by mass; At least one of 0.3-0.6% by mass of Cu and 0.3-1.5% by mass of Mn; and The rest is Al and impurities. 2. The aluminum alloy brazing material according to claim 1, wherein the content of Si is 6-12.5% by mass. 3. The aluminum alloy brazing material according to claim 1 or 2, characterized in that the content of Zn is 2-7% by mass. 4. The aluminum alloy brazing material according to any one of claims 1 to 3, characterized in that the content of Cu is 0.4-0.55% by mass. 5. The aluminum alloy brazing material according to any one of claims 1 to 4, characterized in that the content of Mn is 0.4-1% by mass. 6. A brazing part comprising an aluminum or aluminum alloy base material and a brazing layer formed on the surface of the base material, wherein the brazing layer is defined by any one of claims 1 to 5 Sprayed layer of aluminum alloy brazing material. 7. A brazing product comprising: a brazing member as defined in claim 6; and a joint, Wherein, the brazing part and the joining part are brazed together through the brazing layer of the brazing part. 8. A method for manufacturing a brazing product, comprising the following steps: Brazing is prepared by spraying the aluminum alloy brazing material defined in any one of claims 1 to 5 onto the surface of an aluminum or aluminum alloy substrate to form a brazing layer; and The brazing part and the other joining part are heated in combination to braze the brazing part and the joining part together through the brazing layer. 9. The method for manufacturing brazed products according to claim 8, wherein the brazing step is performed under normal pressure. 10. A brazed heat exchange tube, comprising: An aluminum or aluminum alloy heat exchange tube substrate; and a brazing layer formed on the surface of the heat exchange tube base material, Wherein, the brazing layer is a sprayed layer of the aluminum alloy brazing material defined in any one of claims 1 to 5. 11. The brazed heat exchange tube according to claim 10, wherein the base material of the heat exchange tube is made of JIS A1000 series alloy. 12. The brazed heat exchange tube according to claim 10, wherein the base material of the heat exchange tube is made of JIS A3003 series alloy. 13. The brazed heat exchange tube according to claim 10, wherein the base material of the heat exchange tube is made of Al containing more than 0.2 mass% but not more than 0.6 mass% of Cu and 0.15-2 mass% of Mn -Cu-Mn series alloys. 14. The brazed heat exchange tube according to claim 13, characterized in that, in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.15-0.4% by mass . 15. The brazed heat exchange tube according to claim 13, characterized in that, in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.6-1.5% by mass . 16. A heat exchanger comprising: A brazed heat exchange tube as defined in claim 10; and fins, Wherein, the heat exchange tube and the fin are brazed together through the brazing layer of the heat exchange tube. 17. The heat exchanger according to claim 16, characterized in that, the heat exchange tube base material of the brazed heat exchange tube is a JIS A1000 series alloy. 18. The heat exchanger according to claim 16, characterized in that, the heat exchange tube base material of the brazed heat exchange tube is a JIS A3003 series alloy. 19. The heat exchanger according to claim 16, characterized in that the heat exchange tube base material of the brazed heat exchange tube is composed of more than 0.2 mass % but not more than 0.6 mass % of Cu and 0.15-2 mass % Made of Mn Al-Cu-Mn series alloys. 20. The heat exchanger according to claim 19, characterized in that, in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.15-0.4% by mass. 21. The heat exchanger according to claim 19, characterized in that, in the Al-Cu-Mn series alloy, the content of Cu is 0.25-0.5% by mass, and the content of Mn is 0.6-1.5% by mass. 22. The heat exchanger according to any one of claims 16 to 21, wherein the fins are made of JIS A3000 series alloy. 23. A method of manufacturing a heat exchanger, comprising the steps of: Brazing heat exchange tubes are produced by spraying the aluminum alloy brazing material defined in any one of claims 1 to 5 onto the surface of an aluminum or aluminum alloy heat exchange tube base material to form a brazing layer; and The brazed heat exchange tubes and the fins are heated in combination to braze the brazed heat exchange tubes and the fins together through the brazing layer of the brazed heat exchange tubes. 24. The heat exchanger manufacturing method according to claim 23, characterized in that, the step of preparing the brazed heat exchange tube is carried out as follows: that is, the base material of the heat exchange tube is formed by extrusion, and then the aluminum alloy brazing material Spray onto the heat exchange tube substrate. 25. The heat exchanger manufacturing method according to claim 23 or 24, characterized in that the brazing step is performed under normal pressure.

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