JP2001259886A - Brazing sheet of aluminum alloy and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remedy the poorness of workability and working environment in a flux coating application system after assembly of a heat exchanger. SOLUTION: A flux sealed member consisting of an aluminum alloy material formed by sealing fluxes to regular patterns at an area rate of 40 to 95% is disposed in the boundary between a brazing filler metal and a core and the surface of the brazing filler metal. As the blux sealing member, 1. a perforated extrusion tube previously sealed with the fluxes and 2. the aluminum alloy members formed by disposing aluminum alloy spacers at specific intervals on an aluminum alloy sheet and inserting the fluxes therebetween, then superposing the aluminum alloy sheet thereon are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing sheet made of an aluminum alloy which does not require the application of a flux during brazing and has excellent workability and brazeability, and a method for producing the same.

[0002]

2. Description of the Related Art A brazing sheet made of an aluminum alloy is composed of a laminated plate in which a brazing material is used as a skin material and combined with a core material. This brazing sheet is used for a heat exchanger for an automobile, for example, a radiator or a cooler, and its usage is increasing year by year.

[0003] The production of these heat exchangers is mainly performed in the order of cutting, forming, degreasing, assembling, flux application and brazing of the brazing sheet.

[0004]

The heat exchanger has a complicated shape and a large surface area in order to improve the heat radiation function.
With the flux application method after assembly, it is not easy to apply to the complicated inner surface, and powdered flux that may have a bad effect on the human body during handling after application is apt to fall off and scatter and the working environment is bad There was.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to produce a brazing sheet of an aluminum alloy excellent in workability and brazing ability, which can omit the application of a complicated and large-area flux before brazing.

[0006]

In order to solve the above-mentioned problems, the present invention replaces the conventional flux coating after assembly and before brazing with 1/10 of the final brazing sheet.
The flux enclosing member is arranged at the stage of the base material before clad rolling having a small area of less than 00 and a simple flat shape.

At this time, if the portions where the flux is filled are arranged in a regular pattern (for example, a striped pattern or a plurality of strips) and at a fixed area ratio, there is no interface peeling or swelling and the flux is not brazed. It has been found that the wetting action is performed entirely.

That is, the invention of claim 1 is a flux encapsulation made of an aluminum alloy material in which flux is encapsulated in a regular pattern at an area ratio of 40 to 95% at the interface between the brazing material and the core material or on the surface of the brazing material. This is a brazing sheet of an aluminum alloy excellent in brazing workability, in which members are arranged.

According to a second aspect of the present invention, as the flux enclosing member, a multi-hole extruded tube in which a flux is preliminarily enclosed is used, and the flux enclosing member is disposed at the interface between the brazing material and the core material or on the surface of the brazing material. The method for producing a brazing sheet of an aluminum alloy excellent in brazing workability according to claim 1, wherein the brazing sheet is subjected to clad bonding.

[0010] Furthermore, the invention of claim 3 is an aluminum alloy having a structure in which an aluminum alloy spacer is arranged at a specific interval on an aluminum alloy plate as a flux enclosing member, a flux is inserted therebetween, and an aluminum alloy plate is stacked thereon. Using an alloy member, after arranging this flux enclosing member on the interface between the brazing material and the core material or on the surface of the brazing material,
The method for producing a brazing sheet of an aluminum alloy excellent in brazing workability according to claim 1, wherein the brazing sheet is clad-bonded.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, the brazing alloy of the brazing sheet made of an aluminum alloy is not particularly limited, but is usually an Al-Si-based alloy, and further, Zn, Sn, Cu,
A brazing material to which at least one of In and Bi is added, for example, JISA4003, 4004, 4104, 4N04, etc. can be preferably used.

The aluminum alloy sheet, the multi-hole extruded tube, and the core alloy for enclosing the flux are not particularly limited, but pure Al-based or Al-Mn-based alloys for industrial use, and Cu, Mg, Ti , Si or the like added thereto, for example, JISA1070, 1050, 1100, 1
200, 3003, 3203, 3004, 5005, 5
N01,6061,6063,6N01,6951,7
N01 and the like can be preferably used.

The brazing material may be on one side or both sides. The cladding ratio is preferably 5 to 20% per one side. If the cladding ratio is less than 5%, the production becomes difficult, and the brazing property is reduced due to insufficient brazing material. On the other hand, if the cladding ratio exceeds 20%, it is not preferable because the thickness is unnecessary, meaningless and economical.

The clad ratio of the aluminum alloy member in which the flux is sealed is preferably 1 to 5%.

[0015] The type of flux is not limited.
Non-corrosive fluoride-based fluxes are preferred, K, Al,
Compounds containing F, Cs, etc., for example, KAlF ₄ , K ₂ Al
It is a simple substance or a mixture of F ₅ .H ₂ O, K ₃ AlF _{6 and the} like.

The amount of the flux may be adjusted to 0.1 to 10 g / m ² when the final plate is formed by clad pressure bonding.

The arranging portion serves as a flux supply source, and the non-arranging portion serves as a pressure bonding portion between the brazing material and the core material or between the flux-encapsulated aluminum member and the brazing material. If the area ratio of the flux arranging portion in a plan view is less than 40%, it is not preferable because the entire surface of the flux hardly occurs during brazing. On the other hand, if it exceeds 95%, the area of the flux non-arranged portion, that is, the area of the pressure bonding portion between the brazing material and the core material or between the flux-encapsulated aluminum member and the brazing material is insufficient, and swelling is likely to occur at these interfaces. Absent.

Therefore, the area ratio of the flux arrangement portion is 40
To 95%.

It is presumed that the reason why the flux can be completely wetted even under the condition where the flux non-arranged portion of the present invention exists is as follows.

That is, since the melting point of the flux is lower than that of the brazing material, the melting of the flux occurs first when the brazing is heated. In this state, the flux remains sealed in the aluminum alloy member. When the temperature rises and the wax melts,
The coexistence of two-flux separation of wax and flux. At this stage, the aluminum alloy member containing the flux is melted by erosion with the molten brazing material, and the molten brazing material obtained by melting and mixing the aluminum alloy member and the molten flux are integrated. Here, the flux floats on the surface of the molten brazing material because the flux is lighter. At this time, it is considered that the dissolving action of the oxide film by the flux occurs and the entire surface is wet.

The regular pattern is preferably a striped pattern or a plurality of band-shaped patterns. The size of the arrangement of the flux is in the state of the final plate. In the case of a band as shown in FIG. Width is 1-10mm, pitch is 10-100
3B, the width is 1 to 10 mm in the width direction and the longitudinal direction, and the pitch is 10 in the width direction.
It is preferably from 100 mm to 100 mm in the longitudinal direction.
The flux enclosing size in the stage before rolling is determined so that the width and pitch are obtained in the stage of the final plate by calculating from the rolling ratio and the like.

In FIG. 3, the flux arranging portion is represented by a rectangle. However, it is not necessary that the flux be a regular pattern and a rectangular shape as long as the area ratio satisfies the above condition.

The reason why the flux encapsulation of the present invention is arranged in a regular pattern (for example, a striped pattern or a plurality of strips) at the interface does not cause peeling or swelling at the interface because the brazing material and the core are not disposed at the flux non-arranged portion. This is probably because the material or the flux enclosing member and the brazing material are pressure-bonded, and the pressure-bonded portion exists in a striped shape or a plurality of band-shaped patterns turned upside down.

The width and pitch of the aluminum alloy spacer on the aluminum alloy plate of the aluminum alloy member for enclosing the bone and the flux of the multi-hole extruded tube may be any as long as they correspond to the size and pitch of the non-arranged portion in the width direction. .

As a method of enclosing the flux in the multi-hole extrusion tube, the powder may be used as it is, but it is preferable that the flux is made water turbid, and then the flux is dried after entering the hole.

In the case of an aluminum alloy member in which an aluminum alloy spacer is disposed between aluminum alloy plates to enclose a flux, it is preferable that the encapsulation of the flux is performed by powder before lamination.

It is also desirable to wrap the entire laminated aluminum alloy member with an aluminum foil or the like after the flux encapsulation and lamination, from the viewpoint of simplicity of handling.

The total thickness of the flux-encapsulated aluminum alloy member before clad rolling is not particularly limited in the case of interfacial insertion between the brazing material and the core material, but is generally preferably 0.5 to 5 mm, and is preferably arranged on the surface of the brazing material. In this case, the thickness is preferably 5 to 50 mm.

In the case where the interface between the brazing material and the core material is inserted, the flux-encapsulated aluminum alloy member acts as a glue instead of glue at the time of pressure bonding, that is, serves as a joining aid. However, when the thickness exceeds 5 mm, the pressure bonding property is reduced. If the thickness is less than 0.5 mm, it is too thin to handle in a large size.

In the case of disposing on the brazing material surface, if the total thickness before the clad rolling is less than 5 mm, the thickness becomes 1/1000 or less when rolling to the final plate, so that the aluminum member serving as the skin of the flux enclosing portion is not formed. It becomes thin and easily peels off. If the thickness exceeds 50 mm, erosion from the brazing material becomes difficult at the time of melting of the brazing material, so that the fusion with the molten brazing material does not occur.

Usually, hot rolling is used as the means for clad pressure bonding. After hot rolling, cold rolling and appropriate annealing are performed to obtain a brazing sheet having a final thickness.

Usually, the brazing atmosphere is preferably carried out in nitrogen, but it is also possible to carry out the brazing in air by increasing the flux.

[0033]

EXAMPLE 1 A multi-hole extrusion tube (material: pure 99.5% pure Al, full width: 100 m) was prepared by suspending a mixed flux of KAlF ₄ and K ₃ AlF ₆ in water at a concentration of 20%.
m, total thickness: 8 mm, wall thickness: 2 mm, total length: 200 mm,
(Hole size: 22 holes, 4 mm height, 4 mm width) One end of the sealed hole is filled with 85% of the space amount, and the other end is sealed leaving the upper part of the hole and heated to a horizontal state, leaving the upper part of the hole sealed. Moisture was evaporated to dryness from the part.

Thereafter, an Al-1.1% Mn alloy plate (50 m
m thickness x 100 mm x 200 mm) as a core material, and an Al-10% Si alloy brazing plate (8 mm thickness x 100 m) on both surfaces thereof
mx 200 mm), and the above-mentioned flux-encapsulated tube was arranged on the brazing filler metal surface and combined. This is heated to 480 ° C. in a heating furnace, and then hot pressed and rolled.
It was a laminated plate having a thickness of mm. This was further cold-rolled to 0.5 mm and subjected to final annealing at 400 ° C. for 2 hours.

When the surface of this plate was observed, a good brazing sheet was obtained without any swelling or peeling. still,
At this time, the flux arrangement area ratio was 88%, and the flux amount in the final plate was 6 g / m ² · one side.

This brazing sheet (0.5 mm thick ×
A T-joint test piece having a shape shown in FIG. 2 was assembled by combining a 30 mm × 60 mm) and a 3003 base material plate (1.0 mm × 30 mm × 60 mm).

The test piece was put into an atmosphere brazing furnace (nitrogen atmosphere, dew point: -40 ° C., temperature: 600 ° C.), held for 1 minute after reaching the maximum temperature, and taken out of the furnace.

As a result, it was confirmed that a good brazing joint was formed over the entire length of the fillet portion.

For comparison, the same combination as described above was used, except that the arrangement of the flux-encapsulated tube on the surface of the brazing material was omitted, and brazing was performed without applying the flux as in the present invention. As a result, no fillet was formed.

As described above, it was confirmed that the brazing sheet of the present invention exhibited good bonding properties.

Example 2 A plate of JIS A1050 (1.
JIS A1050 spacer (0.3mm thickness) as shown in Table 1 above (0mm thickness x 100mm width x 200mm length)
Was placed. Then JIS A1050 between the spacers
A powder flux of the same type as that used in Example 1 was placed on the plate having an average thickness of 0.3 mm, and the same JIS as described above was further placed thereon.
A1050 plate is placed and the whole is aluminum foil (10 μm
Thickness) and wrapped in a pack. This pack was inserted into the interface between the brazing material and the core material having the same chemical composition and dimensions as in Example 1, and the subsequent treatment was performed in the same manner as in Example 1 to obtain a brazed sheet after annealing.

When the surface of this plate was observed, a good brazing sheet was obtained without any swelling or peeling. Further, a brazing test using a T-joint test piece was performed in the same manner as in Example 1.

The flux amount at this time was about 8 g / m ²
・ It is one side.

The results are shown in Table 1.

[0045]

[Table 1]

For comparison, the size of the spacer,
Table 1 also shows the results of evaluating T-joint test specimens prepared in the same manner as described above except that the arrangement area ratio was arranged under conditions outside the present invention.

As a result, it was confirmed that the brazing sheet of the present invention exhibited good brazing properties.

[0048]

As described above, according to the present invention, as described above, the flux application instead of the current flux application of a complicated shape and a large area before brazing is replaced with a simple flat shape before hot clad bonding. And 1/1000 of the final processing area
Since the arrangement of the flux enclosing member for the following small area is sufficient, brazing workability is excellent.

At this time, since the sealing of the flux is performed in a regular pattern and at a constant area ratio, there is no interface peeling or swelling, and the effect of wetting of the flux by brazing is entirely performed, and good brazing is performed. Can be achieved.

In addition, in the current application of the flux after assembling, the flux must be applied to members other than the brazing sheet constituting the heat exchanger, so that waste of the flux occurs. Waste can be omitted.

Further, with the material of the present invention, there is no falling off and scattering of the powdery flux before brazing, and the work environment is excellent.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a laminated structure of a brazing sheet of the present invention, wherein (a) shows a case where a flux enclosing member is inserted into an interface between a brazing material and a core material, and (b) shows a state where a flux enclosing member is inserted into a brazing material surface. It is a case where it arrange | positions at.

FIG. 2 is an external view of a T joint test piece used for the test.

FIGS. 3A and 3B are plan views showing the arrangement state of flux in a final plate stage, wherein FIG. 3A shows a case where the flux is arranged in a band shape, and FIG.

[Explanation of symbols]

 1 core material 2 brazing material 3 flux enclosing member

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Claims (3)

[Claims] 1. A flux enclosing member comprising an aluminum alloy material in which a flux is encapsulated in a regular pattern at an area ratio of 40 to 95% is disposed at an interface between a brazing material and a core material or on a surface of the brazing material. Aluminum alloy brazing sheet with excellent brazing workability. 2. Using a multi-hole extruded tube in which a flux has been sealed in advance as a flux enclosing member, disposing the flux enclosing member on the interface between the brazing material and the core material or on the surface of the brazing material, and then performing clad pressure bonding. The method for producing a brazing sheet of an aluminum alloy according to claim 1, which is excellent in brazing workability. 3. An aluminum alloy member having an aluminum alloy spacer disposed at a specific interval on a aluminum alloy plate, a flux inserted between the spacers, and an aluminum alloy plate overlaid on the aluminum alloy plate as a flux enclosing member. 2. The method for producing a brazing sheet of an aluminum alloy having excellent brazing workability according to claim 1, wherein the enclosing member is disposed on the interface between the brazing material and the core material or on the surface of the brazing material and then clad-bonded. .