JP2000126863A - Method for coating brazing filler metal or/and flux onto aluminum alloy flat tube and aluminum alloy flat tube coating brazing filler metal or/and flux by the above method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a heating furnace and to improve the productivity by carrying short aluminum alloy flat tube arranged in a major axial direction, minor axial direction or intermediate direction thereof to the major direction, minor direction or the intermediate direction thereof and coating the mixture of brazing filler metal or/and flux and binder resin. SOLUTION: The short Al alloy flat tubes 1 are fastened by arranging in the major axial direction in a fitting zone 2. This short Al alloy flat tube 1 is carried in the major axial direction and the mixture 4 of the brazing filler metal powder or/and the flux and the binder are coated on the short Al alloy flat tube 1 in a dipping vessel 3. The binder resin is hardened in a heating furnace 5 and the short Al alloy flat tube 1 coated with the brazing filler metal or/and the flux is taken off in a taking-off zone 6. When the interval of the short Al alloy flat tubes 1 is narrowed and the short Al alloy flat tubes are horizontally arranged and vertically carried, the mixture 4 is uniformly applied and coated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating an aluminum alloy flat tube used for a heat exchanger or the like with a brazing material and / or flux in a good and high productivity, and a method for coating a brazing material and / or a flux. Aluminum alloy flat tubes.

[0002]

2. Description of the Related Art For example, as shown in FIG. 3, a core of a condenser, which is a kind of heat exchanger, has a brazing material between aluminum alloy flat tubes (hereinafter, abbreviated as flat tubes) 21 through which a refrigerant passes. The clad fins 22 are arranged, the header pipes 7 are attached to both ends of the flat tube 21, the core 8 is assembled, and the assembled body is integrally brazed by a brazing method. As the flat tube 21, a single-hole flat tube 9 made of an aluminum alloy shown in FIG. 4A or a flat multi-hole tube 19 made of an aluminum alloy shown in FIG. 4B is used. In recent years, as heat exchangers are required to be smaller and lighter, the fins 22 having a limit in thinning from the viewpoint of brazing diffusion are reduced to bare fins in the core portion 8 of the capacitor, and the brazing material is made of a flat tube. A method of brazing by coating the surface with a binder resin has been proposed (JP-A-9-70660).

[0003]

By the way, in a laboratory, a method of coating a flat tube surface with a brazing material using a binder resin is a method of coating a mixture of a brazing material powder and a binder resin with a roll coater, dipping, and brushing. The coating is performed by coating, and then the binder resin is cured by heating. On the other hand, on an industrial scale, as shown in FIG. 5, a long aluminum alloy flat tube (hereinafter abbreviated as a long flat tube) 11 supplied from an uncoiler 10 is provided with a dipping tank 3.
Then, a mixture 4 of a brazing filler metal powder or / and a flux and a binder resin is applied, the binder resin is hardened through a vertical heating furnace 15 while being vertically pulled up, and then wound around a coil 16. ing. Here, the reason why the flat tube after application of the mixture is pulled up vertically and passed through the vertical heating furnace as it is is to prevent the mixture from becoming uneven due to flow. However, this method has the following problems. That is, the curing of the binder resin takes about 2 minutes, and the length of the heating furnace is required to be 3 m even if the transport speed is reduced to about 1.5 m / min. Incidentally, when a flat multi-hole tube having a width of 16 mm is coated at a speed of 1.5 m / min, the production amount is only 4 kg per hour. Further, when the conveying speed is increased, the mixture is applied unevenly, and there is a problem that the brazing property is deteriorated. Further, the vertical heating furnace is expensive and disadvantageous in cost. An object of the present invention is to provide a method for coating an aluminum alloy flat tube used for a capacitor or the like with a brazing material and / or a flux with good and high productivity, and to provide an aluminum alloy flat tube coated with a brazing material and / or a flux. And

[0004]

According to the first aspect of the present invention,
In the major axis direction, the minor axis direction, or a plurality of short aluminum alloy flat tubes arranged in the middle direction, the major axis direction,
An aluminum alloy flat plate which is conveyed in a minor axis direction or an intermediate direction to apply a brazing powder or / and a mixture of a flux and a binder resin, and then hardens the binder resin through a heating furnace. This is a method of coating a pipe with brazing material and / or flux.

According to a second aspect of the present invention, there is provided the aluminum alloy flat tube according to the first aspect, wherein the short aluminum alloy flat tube is a flat multi-hole tube.
And a method of coating flux.

According to a third aspect of the present invention, a plurality of short aluminum alloy flat tubes arranged in a major axis direction, a minor axis direction, or an intermediate direction thereof are passed while meandering in a heating furnace. Or a method of coating the aluminum alloy flat tube with a brazing material and / or flux.

According to a fourth aspect of the present invention, the gap for arranging the aluminum alloy flat tubes is set to 5 mm or less. And a method of coating flux.

According to a fifth aspect of the present invention, there is provided the aluminum alloy flat tube according to any one of the first to third aspects, wherein the aluminum alloy flat tube is conveyed in a line. And / or a method of coating flux.

The invention according to claim 6 is characterized in that the application of the mixture is performed by a dipping method.
A method of coating the aluminum alloy flat tube according to any one of 2, 3, 4, and 5 with a brazing material and / or flux.

According to a seventh aspect of the present invention, the aluminum alloy flat tube according to any one of the first, second, third, fourth, fifth and sixth aspects is characterized in that a water-soluble binder resin is used as the binder resin. This is a method of coating a material and / or a flux.

The invention according to claim 8 is characterized in that both ends of the short aluminum alloy flat tube are chucked while also masking 2 to 20 mm.
2. A method of coating a flat tube of an aluminum alloy according to any one of 2, 3, 4, 5, 6, and 7 with a brazing material and / or a flux.

According to a ninth aspect of the present invention, there is provided an aluminum alloy flat tube, wherein the surface of the aluminum alloy flat tube is coated with a brazing material and / or a flux except for both ends of 2 to 20 mm. .

[0013]

According to the first aspect of the present invention, an aluminum alloy flat tube is conveyed and coated with a brazing powder or / and a mixture of a flux and a binder resin, and then passed through a heating furnace to form the binder resin. In the method of heat curing, the aluminum alloy flat tube is cut into short lengths, and the short flat tubes are arranged in the long diameter direction, the short diameter direction, or the middle direction thereof, respectively, in the long diameter direction, the short diameter direction, or in the middle direction thereof. By transporting, the heating furnace is reduced in size or the productivity is increased. As long as the intermediate direction is a direction intermediate between the major axis direction and the minor axis direction, the intermediate direction may take an arbitrary direction even near the major axis direction, near the minor axis direction, or at a completely intermediate direction. The flat tube may have any shape, such as an elliptical cross-sectional profile, a straight long side and a short side arc. The flat tube includes, for example, a simple one-hole flat tube 9 (see FIG. 4a) manufactured by electric-resistance-welding a thin-walled material, and a flat multi-hole tube 19 (see FIG. 4b) manufactured by extrusion. Used. The cross-sectional shape of the hole of the flat multi-hole tube 19 is arbitrary, such as a rectangle, a rectangle having a round corner, and an ellipse.

The present invention will be specifically described below with reference to the drawings. FIG. 1 is a process explanatory view showing an embodiment of the coating method of the present invention. In this coating method, a short aluminum alloy flat tube (hereinafter, abbreviated as a short flat tube) 1 is arranged and chucked in a long diameter direction in an attachment zone 2, and the short flat tube after chucking is conveyed in a long diameter direction. A step of applying a brazing powder or / and a mixture 4 of a flux and a binder resin to the short flat tube 1 in a dipping tank 3, a step of curing the binder resin in a heating furnace 5,
A step of removing the short flat tube 1 coated with the brazing material and / or flux in the removal zone 6. The productivity is improved by transporting the short flat tubes in a multi-row arrangement.

In the present invention, the short flat tube 1 obtained by cutting a normal long flat tube is used. If the cut length is set to a length close to an integral multiple of the length finally used as the flat tube, the loss is small. If the cutting length is long, application and curing of the resin are likely to be uneven, and the equipment is disadvantageously increased in size. Therefore, the length of the short flat tube is preferably about 6 m at the maximum. Recommended length is 100-2000mm
In particular, it is a length that can be used as it is for a device such as a capacitor.

In the present invention, the cross-sectional shape of the short flat tube is arbitrary. In the present invention, the short flat tubes are arranged in the radial direction and conveyed in the radial direction, but when the short flat tubes are flat multi-hole tubes,
As shown in FIG. 2A, the flat multi-hole pipes 9 can be arranged in the major axis direction and transported in the major axis direction, or as shown in FIG. The pipe may be conveyed in the radial direction, or as shown in FIG. 2C, the flat multi-hole tube 9 may be conveyed in the intermediate direction by arranging it in an intermediate direction between the major axis direction and the minor axis direction.

In the present invention, the gap in which short flat tubes are arranged is recommended to be 5 mm or less in consideration of productivity. Also, 5m
When a plurality of short flat tubes arranged horizontally with a gap of m or less are conveyed in the vertical direction, the mixture applied to the surface of the short flat tubes successively flows from the upper short flat tubes to the lower short flat tubes. When the binder resin is cured in such a steady state, a uniform coating state can be obtained. It is particularly recommended that the gap in which the short flat tubes are arranged is 4 mm or less.

[0018] JIS3003 alloy, JIS1100 alloy, Al
-Cu-based alloys, Al-Mn-Cu-based alloys, and composite materials obtained by coating these alloys with Al-Zn-based alloys or pure aluminum-based alloys can be used. The above alloy is an example, and any aluminum alloy or composite material that satisfies the characteristics required for each application can be used for the short flat tube. The short flat tube used in the present invention is obtained by cutting a long flat tube manufactured by a conventional method such as extrusion or welding into a predetermined length. The cross-sectional shape and dimensions of the short flat tube are designed according to the equipment used, and are not particularly limited.

In the present invention, an Al alloy powder for brazing, a Si powder, or the like is used as the brazing filler metal powder. Al-Si alloy powder, Al-
Representative examples include a Zn-based alloy powder and an Al-Cu-based alloy powder, but are not limited thereto, and any brazing material that can be brazed is used. In consideration of the corrosion resistance and the fluidity of the solder, in particular, Al-Si alloy powder, Al-Si-
Zn-based alloy powder, Al-Si-Cu-based alloy powder, Al-
Si-Cu-Zn-based alloy powder, Al-Cu-Zn-based alloy powder and the like are recommended.

In the present invention, the brazing filler metal powder is preferably fine from the viewpoint of preventing sedimentation in the mixture, and it is desirable that the powder having a particle diameter of 250 μm or less be 90 wt% or more. In particular, it is recommended that the powder having a particle diameter of 100 μm or less be 90 wt% or more. On the other hand, after being coated, the finer the brazing filler metal powder, the more difficult it is to peel off. On the other hand, if the particle size of the brazing material powder is small, the surface area increases, the amount of the oxide film increases, and the brazing property decreases. Therefore, it is desirable that the powder having a particle diameter of 3 μm or more, more preferably 5 μm or more, is 90% or more.

The shape of the brazing filler metal powder is desirably close to a spherical shape in terms of transportation and uniform dispersion. Therefore, the powder produced by quenching the molten metal by the atomizing method or the like is more preferable than the powder obtained by pulverizing the solidified brazing filler metal. Is better. On the other hand, from the viewpoint of brazing properties, powder having a shape close to a plate is preferred, and pulverized powder or powder crushed by a ball mill or the like is suitable. When the shape of the powder is different from the spherical shape, the particle size may be considered as the size when converted into a sphere having the same volume.

In the present invention, it is possible to use Si powder as the brazing filler metal powder. Since Si powder reacts with the aluminum alloy of flat tubes and fins to become brazing material,
It is desirable that the particle size be reduced to 50 μm or less, because the reaction proceeds quickly. In the case of Si powder, a flux for destroying the oxide film on the surface of the aluminum alloy flat tube is required. Since the Si powder does not need to consider an oxide film, there is no problem even if the lower limit of the particle diameter is about 0.5 μm. As the Si powder, a powder produced by a pulverization method is generally used, but the present invention is not limited to this.

The amount of the brazing material powder applied is generally determined by the size of the fillet designed for the equipment to be used.
In particular, in the case of Al alloy brazing powder, 10 g / m ² or more and 15
0 g / m ² or less is desirable. If the amount is less than 10 g / m ² , a fillet of a sufficient size is not formed, and if the amount exceeds 150 g / m ² , most of the surface of the binder resin is covered with the brazing material powder, so that it is difficult to fix. 3 for Si powder
g / m ² or more.

In the present invention, the flux is coated together with the brazing material or alone. The flux is used to break the oxide film on the surface of the aluminum alloy at the time of brazing to enable brazing, and typical examples thereof include fluoride-based, Cs-based, and chloride-based fluxes. In the present invention, any flux can be used. The flux is
It can be coated on the brazing filler metal powder. When the flux is coated alone, a flat tube coated with a brazing material in advance by thermal spraying, a cladding method, or the like is used. A flat tube coated only with a flux is used when a brazing material (such as a fin) is coated with a brazing material.
If a flat tube coated with flux is used, it is not necessary to apply the flux during brazing. If it is a method such as placing it, the application of the flux can be omitted.

There is no problem if the particle size of the flux is equal to the particle size of Si described above. It is recommended that the applied amount of the flux be 0.5 g / m ² or more and 30 g / m ² or less, but it is not necessary to control the applied amount and distribution more precisely than in the case of the brazing powder. In the present invention, powders of zinc, tin, indium, copper, etc. may be simultaneously applied for the purpose of improving corrosion resistance, for example, within a range that does not adversely affect the brazing properties.

The binder resin used in the present invention includes, but is not limited to, acrylic resins, methacrylic resins, urethane resins, epoxy resins, and the like. The binder resin is preferably one that cures in a short time and does not decompose at a temperature equal to or lower than the brazing temperature to deteriorate the brazing property and the corrosion resistance. The binder resin is diluted with a solvent such as water, alcohol, and toluene to adjust the viscosity of the mixture,
It is desirable to control the amount of application stably. Of the solvents, water is particularly recommended because of its easy handling. The coating amount of the binder resin is 10 m in a cured state after the solvent is evaporated.
g / m ² or more and 3 g / m ² or less are desirable. 10mg / m
^If it is less than ² , the coated brazing material or flux will be peeled off by a slight impact. If it exceeds 3 g / m ² , the fixing effect is saturated and the binder resin is wasted, and the curing of the binder resin takes a long time to lower the productivity.

In the present invention, in order to apply the mixture to the Al alloy flat tube, dipping, a roll coater,
Spray coating can be applied. Especially dipping,
It is recommended because the mixture can be applied uniformly.

According to the present invention, productivity is remarkably improved as compared with the conventional method of transporting a long flat tube in the longitudinal direction (see FIG. 5). For example, when a flat tube having a length of 600 mm and a width of 16 mm is arranged in a short diameter direction as shown in FIG. 2 (b) and a resin is cured while being transported in a short diameter direction with a gap of 4 mm, As compared with the conventional method shown in FIG. In this case, the transfer speed is 1/10
Even so, the production amount is tripled, and it is possible to reduce the transport speed while increasing the productivity. If the transport speed can be reduced, the flow of the mixture until the binder resin is cured can be prevented. The binder resin may be cured by a heating method or an energy beam irradiation method, but the heating method is recommended because a solvent useful for adjusting the coating amount of the brazing material or the flux can be quickly evaporated.

In the present invention, the short flat tube after the application of the mixture is conveyed in a meandering manner in the heating furnace, so that the inside of the furnace can be used effectively. If the mixture flows due to meandering, meandering may be performed after the binder resin is cured.
In the conventional method, since the flat tube is long, a guide roll is necessary to meander the flat tube, and the binder resin adheres to the guide roll, and the coating thickness of the mixture becomes uneven. There is. However, in the present invention, if the end of the short flat tube is chucked and conveyed, it is possible to meander without using a roll.

The end for chucking the short flat tube is a portion that is inserted into the header pipe and does not need to be coated with a brazing material or the like. Therefore, in the present invention, the gap between the flat tube and the insertion hole of the header pipe is reduced by masking the end of the short flat tube at the time of chucking and not covering the brazing material or the like, and the brazing material is good. To be filled. If the masking length is less than 2 mm, chucking cannot be performed sufficiently. If the masking length exceeds 20 mm, the required region of the brazing material or flux is not covered with the brazing material or flux. Therefore, the masking length is set to 2 to 20 mm. A thickness of 3 to 12 mm is particularly recommended because of ease of handling and ease of coating.

In the present invention, when the mixture is coated by dipping, it is possible to prevent the mixture from entering the flat tube by chucking so as to close the open end of the flat tube end.

The flat tube obtained by the present invention can be applied to a field that does not require brazing, and its use is not limited, but it is particularly useful for a heat exchanger of an automobile or the like.

[0033]

The present invention will be specifically described below with reference to examples. (Example 1) A multi-hole flat tube (thickness 1.8 mm, width 16 mm, JIS A1050 Al alloy manufactured by hot extrusion)
After cutting and degreasing a length of about 2 km and 8 holes) into a short length of 580 mm, this short flat tube (multi-hole flat tube)
And the flux was coated in accordance with the process shown in (1). The mixture includes four types of mixtures (A to
D) was used. The Al alloy brazing filler metal powders A and B in the mixture contain 0.6 wt% of Fe as an unavoidable impurity.
Hereinafter, Cu, Zn, Mn, Ti, etc. are each 0.05 wt.
% Or less is included. A water-soluble polyether resin was used as the binder resin, and the viscosity of the mixture was changed by adding water as a solvent. The short flat tubes were arranged in the longitudinal direction with a gap of 3 mm, and chucked so that both ends were masked by 10 mm each, and that the mixture 2 did not enter the flat tubes 1. The mixture 2 applied to the surface of the short flat tube 1 flowed between the short flat tubes from the dipping tank 4 to reach the heating furnace 5 (about 500 mm), so that a uniform coating state was obtained. The heating furnace 5 has a box shape with an outer dimension of 0.6 mx 1 mx 1 m and an internal temperature of 20 m.
It was set to 0 ° C. Each short flat tube 1 was meandered after the solvent was evaporated and the resin was cured in the heating furnace 5. Due to the meandering, the passing distance of each short flat tube 1 in the heating furnace 5 is about 1.2 m.
Became. Each flat tube 1 coming out of the heating furnace 5 was removed from the line in a removal zone 6. The line speed was set to 0.6 m / min so that the binder resin was heated in the heating furnace for 2 minutes and completely cured.

(Conventional Example 1) According to the conventional process shown in FIG. 5, a long aluminum alloy flat tube is coated with a brazing material and / or flux, wound around a coil, and the long flat tube is unwound and adjusted. It was cut to a fixed length of 580 mm. The length of the heating furnace was 3 m, and the temperature in the furnace was set to 200 ° C. The heating time is required to completely cure the binder resin.
Minutes and the line speed was adjusted to 1.5 m / min. The same flat tube or mixture as in Example 1 was used.

Table 2 shows the output per hour of the coated flat tubes in Example 1 and the conventional example.

[0036]

[Table 1] (Note) * Type of mixture (see Table 1). * Coverage.

[0037]

[Table 2] (Note) * Type of mixture (see Table 1).

As is clear from Table 2, No. 1 of the present invention example
No. 4 to No. 5 to No. 5 to No. 8 of the conventional example, about 12 times the production amount.

(Example 2) A fin and a header pipe were assembled to the short flat tube obtained in Example 1, and the length was set at 595 ° C.
The core of the capacitor was manufactured by heating and brazing for 5 minutes. The short flat tubes (No.1,2,4) coated with the brazing material have a corrugated Al-0.5Si-1% Fe-0.5% Ni-2% Zn alloy fin (0.07mm thickness), A 3003 alloy tube and a header pipe in which 4045 alloy was clad (clad ratio: 5%) were assembled. In the above No.2 (only brazing material is coated),
Before brazing and heating, a fluoride-based flux was applied to required portions of the core. Flat tube coated only with flux (N
o.3) includes a fin obtained by corrugating a 0.13 mm thick brazing sheet in which both sides of a 3003 alloy strip (core material) are clad with 4045 alloy strip (cladding ratio: 8%);
A header pipe in which a 4045 alloy was clad (cladding ratio: 5%) was assembled to a 03 alloy tube.

(Conventional Example 2) A fin and a header pipe were assembled to the short flat tube obtained in Conventional Example 1 and the assembly was performed at 595 ° C.
The core of the capacitor was manufactured by heating and brazing for 5 minutes. The brazing material coated (Nos. 5, 6, and 8) used the same fins and header pipes as those used for the short flat tubes (Nos. 1, 2, and 4) of Example 2, and used only the brazing material. Coated (No.7)
The same fins and header pipes used for the short flat tube (No. 3) of Example 2 were used. Others were the same as Example 2.

With respect to the core portion of each of the obtained capacitors, a leak test was performed by flowing water into the core portion, and the occurrence of leakage at the brazing portion between the header pipe and the flat tube was examined. Further, the brazing property was evaluated based on the adhesion rate of the fin. The adhesion ratio (%) of the fin was determined by peeling the fin from the flat tube and multiplying (length of the bonded portion) / (length of the bonded portion + length of the non-bonded portion) by 100 times. . Table 3 shows the results.

[0042]

[Table 3] * Type of mixture (see Table 1).

As is evident from Table 3, it was found that the tubes using the flat tubes of the present invention (Nos. 9 to 12) had no leakage and were well brazed at any part.
In addition, the fin adhesion rates were all 100%. On the other hand, in the comparative examples (Nos. 13 to 16), leaks occurred between the header pipe and the flat pipe in the leak test. This is because the clearance between the flat tube for insertion and the header pipe was increased because the entire flat tube was covered with brazing material or flux. This can be solved by removing the end coating, but requires extra labor and hinders productivity. The fin adhesion rate was 95 to 80%, and a non-adhesion part was recognized. This is because the resin was cured while the flow state of the applied mixture was unstable due to the high transport speed.
This can be solved by increasing the amount of the brazing material or the amount of the adhered flux, but is disadvantageous in cost.

[0044]

As described above, according to the present invention, a plurality of short aluminum alloy flat tubes arranged in the major axis direction, the minor axis direction, or the intermediate direction thereof are respectively connected to the major axis direction, the minor axis direction, or the intermediate direction. In this case, a mixture of the brazing filler metal powder and / or the flux and the binder resin is applied, and then the binder resin is cured through the heating furnace, so that the heating furnace can be reduced in size or improved in productivity. When the short flat tube is conveyed in a meandering manner in the heating furnace, the above effect is further improved. When the gap between the short flat tubes is narrowed and the short flat tubes are arranged horizontally and conveyed vertically, the mixture moves between the upper and lower short flat tubes, and the mixture is uniformly applied and coated. Further, by chucking the end of the short flat tube also as masking, the gap between the short flat tube and the insertion hole of the header pipe can be narrowed, and good brazing can be performed. Therefore, an industrially remarkable effect is achieved.

[Brief description of the drawings]

FIG. 1 is a process explanatory view showing an embodiment of a coating method of the present invention.

FIGS. 2 (a), (b) and (c) are explanatory views showing examples of how to arrange short flat tubes and the direction of conveyance in the present invention.

FIG. 3 is an explanatory diagram of a core part of a capacitor.

FIG. 4 (a) is a perspective view of a single-hole flat tube, and FIG. 4 (b) is a perspective view of a flat multi-hole tube.

FIG. 5 is an explanatory view of a step of a conventional coating method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Short Al alloy flat tube 2 Mounting zone 3 Dipping tank 4 Mixture of brazing filler metal powder or / and flux and binder resin 5 Heating furnace 6 Removal zone 7 Header pipe 8 Capacitor core 9 1-hole flat tube 19 Flat multi-layer Hole tube 10 Uncoiler 11 Long flat aluminum alloy flat tube 15 Vertical heating furnace 16 Coil 21 Flat tube through which refrigerant 22 Fins

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F28F 1/30 F28F 1/30 B 1/32 1/32 B // B23K 101: 14

Claims (9)

[Claims] 1. A plurality of short aluminum alloy flat tubes arranged in a major axis direction, a minor axis direction, or an intermediate direction thereof are conveyed in a major axis direction, a minor axis direction, or an intermediate direction thereof, respectively, and a brazing powder or / And a method of coating the aluminum alloy flat tube with a brazing material and / or flux by applying a mixture of a flux and a binder resin and then curing the binder resin through a heating furnace. 2. The method for coating a flat aluminum alloy tube with a brazing material and / or flux according to claim 1, wherein the flat aluminum alloy tube is a flat multi-hole tube. 3. The aluminum alloy according to claim 1, wherein a plurality of short aluminum alloy flat tubes arranged in a major axis direction, a minor axis direction, or an intermediate direction thereof are passed while meandering in a heating furnace. Brazing material or /
And a method of coating flux. 4. The method for coating a flat aluminum alloy tube with a brazing material and / or flux according to claim 1, wherein a gap for arranging the aluminum alloy flat tubes is 5 mm or less. . 5. The aluminum alloy flat tube according to claim 1, wherein the aluminum alloy flat tube is conveyed in a row.
And a method of coating flux. 6. The aluminum alloy flat tube according to claim 1, wherein the mixture is applied by a dipping method. Method. 7. The method according to claim 1, wherein a water-soluble binder resin is used as the binder resin.
6. The method for coating the aluminum alloy flat tube according to any one of 6 to 6 with a brazing material and / or a flux. 8. The method according to claim 1, wherein both ends of the short aluminum alloy flat tube are chucked while also masking 2 to 20 mm.
7. The method for coating the aluminum alloy flat tube according to any one of items 7 with a brazing material and / or flux. 9. An aluminum alloy flat tube is provided with a brazing material and / or a flux on the surface thereof at both ends thereof by 2 to 2 respectively.
An aluminum alloy flat tube characterized by being coated except for 0 mm.