JP3408864B2 - Method of producing anticorrosion aluminum material for brazing and brazing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is preferably used for a method of manufacturing an aluminum material for brazing used as a constituent member of a heat exchanger manufactured according to the brazing specification, and particularly for a member requiring corrosion resistance. The present invention relates to a method for producing an anticorrosion aluminum material for brazing , and a brazing method .

[0002] In this specification, the term aluminum is used to include its alloys.

[0003]

2. Description of the Related Art There is already known a technique for forming a brazing material layer made of an Al--Si alloy on the surface of an aluminum material by thermal spraying to form a brazing material. However, corrosion resistance cannot be imparted after brazing only by forming the brazing material layer.

Therefore, as a method for producing an aluminum material for brazing which can impart corrosion resistance, first, Zn or a Zn alloy is sprayed on the surface of the aluminum material to form a corrosion-preventing layer before the spray forming of the brazing material layer. A method of spraying a brazing material has been proposed (for example, JP-A-1-15779).
4, JP-A-2-46969).

However, in this method, in order to form the anticorrosion layer and the brazing material layer separately in sequence, the thermal spraying device is used in the front and rear.
Since they have to be arranged in stages, they have drawbacks such as a long production line and high cost.

Therefore, the present applicant has prepared a first powder made of a brazing metal containing a mixed powder of Al and Si and / or an Al--Si alloy powder, and a second powder for corrosion prevention containing Zn. We proposed a method for producing an anticorrosive aluminum material for brazing, which comprises mixing the mixed powders and spraying the mixed powders onto the surface of the aluminum material (Japanese Patent Application No. 5-35).
5017).

According to this prior proposal, since the sprayed layer having the brazing function and the anticorrosion function can be formed by one spraying, it is not necessary to sequentially form the anticorrosion layer and the brazing material layer, and therefore It has become possible to easily produce an anticorrosion aluminum material for brazing.

However, in this method, the Zn powder and the Si powder increase or decrease due to evaporation or the like at the time of thermal spraying. Therefore, the mixing ratio of each metal component such as Si and Zn at the mixed powder stage and the thermal sprayed layer after thermal spraying. The content ratio does not always match. Therefore, S after thermal spraying
It was a little troublesome to adjust the i component and the Zn component to the desired contents or adhesion amounts.

The present invention has been made in view of the above technical background, and an aluminum material for brazing capable of imparting corrosion resistance can be formed by a thermal spraying method without inducing lengthening of a production line. It is intended to provide a method for producing an anticorrosion aluminum material for brazing, which can be easily produced, and can prevent fluctuations in components such as Si and Zn due to thermal spraying , and a brazing method .

[0010]

In order to solve the problems] The above object, Arumini
The flux of aluminum surface is attached to the surface of aluminum material.
The coating amount is 3 to 10 g / m ² , and the Si formation on the surface of the aluminum material
The amount of adhering component is 3 to 20 g / m ² , and the amount of adhering Zn component is 6
Al-Si-Zn-based alloy so that the amount becomes ~ 14 g / m ^2.
Spraying a mixed powder of powder and brazing flux powder
And a method of manufacturing an anticorrosion aluminum material for brazing
Method, and aluminum material surface, aluminum material surface
Of flux of 3 to 10 g / m ² , aluminium
The adhesion amount of Si component on the surface of the aluminum material is 3 to 20 g / m ² , Zn
Al-so that the adhered amount of the component is 6 to 14 g / m ² .
Melt mixed powder of Si-Zn alloy powder and flux powder
Anticorrosion aluminum for brazing manufactured by blasting
Brazing is performed using the material without applying flux.
This is achieved by a brazing method which is characterized by

Al in Al-Si-Zn alloy powder
The Si component and the Si component function as a brazing filler metal component after thermal spraying. Moreover, Zn imparts an anticorrosion effect. Thus, the brazing property and corrosion resistance of the aluminum material depend on the Si component and Z on the surface of the aluminum material after thermal spraying.
Since it largely depends on the amount of the n component deposited, A
The composition of the 1-Si-Zn-based alloy is not so important. Generally, Si: 10 to 30 wt%, Zn: 30 to 70 wt%
%, And the balance Al is used. Further, other components may be contained in addition to Al, Si and Zn as long as they do not affect the brazing property and corrosion resistance of the aluminum material after thermal spraying.

The spraying conditions are not particularly limited,
The desirable thermal spraying conditions are listed below.

First, rather than high temperature spraying such as plasma arc spraying, a spraying temperature of about 1000 to 3000 ° C. (preferably about 2300 to 2900 ° C.) is preferable. If the thermal spraying temperature is less than 1000 ° C, the melting of the powder surface is insufficient and there is a risk that the adhesion with the aluminum material will be poor. Conversely 30
If the temperature exceeds 00 ° C, melting and oxidation of the powder will increase,
In some cases, the brazing property may be deteriorated, or the composition of the coating may be difficult to control due to evaporation of components during melting. A flame spraying method can be mentioned as a spraying method for realizing such a spraying temperature range.

The spraying distance is preferably 50 to 500 mm.
If it is less than 50 mm, not only the powder is excessively melted and the brazing metal particles are oxidized, but also the aluminum material itself may undergo shape change or structure change due to heat. On the other hand, 50
If it exceeds 0 mm, the powder is re-solidified and the adhesion amount is reduced, which may reduce the brazing property. A particularly preferable spraying distance is 150 to 300 mm. Further, the powder supply amount is preferably set to 30 to 180 g / min. 30 g /
If it is less than a minute, the sprayed amount is too small and it takes time to secure the deposited amount, resulting in poor efficiency. If it exceeds 180 g / min, the sprayed layer may be thickened, the difference in shrinkage during cooling may lower the adhesion, and the economy may deteriorate. It is particularly preferable to set it to 90 to 150 g / min. The average particle size of the powder is preferably 200 μm or less. 200μ
When it exceeds m, it becomes difficult to melt and the adhesion yield deteriorates.

Further, the Al-Si-Zn-based powder is used to smoothly pass through the thin nozzle of the spray gun.
It is desirable that 10 wt% or more, preferably 50 wt% or more of the powder is spherical particles.

The above-mentioned thermal spraying is preferably carried out in a non-oxidizing atmosphere such as N ₂ atmosphere in order to prevent the powder particles from being oxidized. In addition, as the powder, it is preferable to use particles having an oxygen concentration of 0.05 wt% or less and having a small degree of oxidation. Oxygen concentration is 0.0
If it exceeds 5 wt%, the adhesiveness will deteriorate and the brazing property will also deteriorate during thermal spraying.

In terms of production efficiency, the thermal spraying is performed continuously while unwinding the coiled aluminum material, or when the aluminum material is extruded, while extruding the aluminum material from the extruder. preferable.

By spraying the Al-Si-Zn-based powder, a sprayed layer made of an Al-Si-Zn-based alloy is formed on the surface of the aluminum material. The amount of Si component deposited on the sprayed layer is preferably 3 to 20 g / m ² . If it is less than 3 g / m ² , brazing may be insufficient thereafter, and 20 g / m ²
If it exceeds m ² , there is a risk of erosion. More preferably, the adhesion amount of Si component in the sprayed layer is 4 g.
/ M ² or more, and preferably 7 g / m ² or less. The amount of Zn component deposited on the sprayed layer is 6 to 14 g.
/ M ² is good. If it is less than 6 g / m ² , the corrosion resistance after brazing may be insufficient, and if it exceeds 14 g / m ² , initial corrosion may be severe and the corrosion resistance may be poor.
More preferably, the amount of Zn component deposited on the sprayed layer is set to 8
It is preferably g / m ² or more and 12 g / m ² or less. There is no particular limitation on the amount of the Al component deposited on the sprayed layer.

The amount of such adhesion is determined by the Al--Si used.
It may be carried out by adjusting the thickness of the sprayed layer in consideration of the Si and Zn contents in the —Zn alloy powder.

The above thermal spraying is preferably performed in a non-oxidizing atmosphere such as an N ₂ atmosphere in order to prevent the powder particles from being oxidized. Further, the sprayed layer may be formed only on one side of the aluminum material, or as shown in FIG. 1, by disposing the spray guns (40) (40) above and below the aluminum material (20) to perform spraying, A sprayed layer may be formed on both upper and lower surfaces.

The composition of the aluminum material used in the present invention is not particularly limited, and various materials required in relation to the application may be used. The method of processing the aluminum material is not particularly limited, and extruded materials, rolled materials, cast materials and various other materials can be used.
Further, the cross-sectional shape of the aluminum material is not limited, and it may be manufactured in any shape determined in relation to the application.

The aluminum material on which the sprayed layer of Al-Si-Zn alloy powder is formed as described above is then subjected to brazing as a constituent member of a brazed product. In particular,
Flux is applied to the joined parts and dried, and then heated to a temperature of about 600 ° C. in an atmosphere of an inert gas such as N ₂ . In the process of temperature increase due to this heating, the sprayed layer is melted and the Zn component in the sprayed layer is diffused to the surface of the aluminum material while destroying the oxide film on the surface of the brazing material to form an anticorrosion layer. In addition, brazing joining is achieved by the brazing filler metal component of the sprayed layer.

By the way, in order to omit the flux applying work when brazing the aluminum material, in the present invention, the sprayed layer in which the Al--Si--Zn alloy and the flux are mixed is formed. Specifically , before thermal spraying, Al-S
The i-Zn alloy powder and the flux powder are mixed into a mixed powder, and the mixed powder is sprayed. The blending ratio of the flux powder is not particularly limited, and may be blended so that the amount of the flux deposited on the sprayed layer is preferably 3 to 10 g / m ² . If the amount of adhered flux in the thermal sprayed layer is less than 3 g / m ² , the flux may be insufficient and brazing may occur. On the other hand, if it exceeds 10 g / m ² , the amount of flux residue on the surface of the aluminum material after brazing increases, and the appearance quality is likely to deteriorate. More preferably,
The amount of flux deposited on the sprayed layer is preferably 4 g / m ² or more, and 7 g / m ² or less.

Although the kind of the flux is not particularly limited, a fluoride-based flux is preferable because it is non-corrosive. As the fluoride-based flux, for example, potassium fluoride (KF) and aluminum fluoride (AlF ₃ ) are contained in a eutectic composition of 45.8: 54.2 in a weight ratio or a composition range close to the eutectic composition to substantially form a complex. Complexed mixture, KAl
Complex compounds such as F ₄ , K ₂ AlF ₅ , and K ₃ AlF ₆ may be used.

Al, Si, when mixing the flux,
The adhesion amount of the Zn component is the same as that when the above-mentioned flux is not mixed. The preferable thermal spraying conditions for mixing the flux are the same as those described above, but the average particle size of the flux is preferably 10 to 200 μm in order to prevent nozzle clogging of the thermal spray gun.

[0026]

Since Al-Si-Zn alloy powder containing both Al and Si for brazing and Zn for corrosion prevention as an alloy is sprayed, it is not necessary to separately form the corrosion prevention layer and the brazing material layer. Only one thermal spraying device is required, and the lengthening of the manufacturing line and the high cost due to the installation of a plurality of thermal spraying devices will not occur.

Further, S in the Al--Si--Zn alloy is
Since the ratios of the i component and the Zn component do not change before and after thermal spraying, by adjusting the ratios of the Si component and the Zn component in the Al-Si-Zn alloy powder as the starting material,
The ratio of the Si component and the Zn component in the sprayed layer can be easily and surely realized.

[0028]

[Example] 16 mm wide made of JIS1070 Al alloy
A porous flat extruded material having a height of 3 mm and a wall thickness of 0.5 mm is extruded from an extruder (10) and then cooled in a cooling water tank (30) as shown in FIGS. ) Was continuously wound up. Then, on the outlet side of the cooling water tank (30), the spray guns (40) (40) were arranged above and below the extruded material (20) in a state of being inclined in the coil direction. Then, thermal spraying was performed while moving the thermal spray guns (4) and (4) with respect to the extruded material at a speed of 50 m / min. As the spray gun (40), a frame type gun having a nozzle portion as shown in FIG. 3 was used. In this spray gun, a mixed fuel gas of combustion gas and oxygen supplied through a fuel feed pipe (41) is ejected from a tip of a nozzle portion and ignited to form a cylindrical frame, and a powder feed pipe (42 The raw material powder (43) fed into the flame together with the carrier gas is heated. Then, the heated powder is atomized by a jet of compressed air supplied from the compressed air supply pipe (44) and is blown forward to be attached to the surface of the extruded material (20). (45) in FIG. 3 shows an air flow. Incidentally, in the thermal spray gun of this embodiment, O ₂ as the fuel gas: 700 liters /
Min, propylene: using a mixed gas of 68 l / min,
The amount of compressed air was 800 liters / minute. The flame temperature (spraying temperature) was about 2700 ° C.

In the above constitution, when the type of Al-Si-Zn powder and the flux are mixed, the mixing ratio of the flux powder and the Al-Si-Zn powder is changed as shown in Table 1 to perform thermal spraying. Then, the sprayed layers (50) and (50) were formed on the upper and lower surfaces of the extruded material (20) by coating. The flux used was 82 wt% KAlF ₄ +18 wt% KK ₃ AlF ₆ and had an average particle size of 80 μm.

Then, with respect to the obtained brazing aluminum material, Al component, Si component, Zn in the sprayed layer
The components and the amount of the adhered flux were measured. The results are shown in Table 1.
Shown in.

Next, each of the brazing aluminum materials produced as described above was used as a heat exchange tube and assembled into a so-called multi-flow type aluminum heat exchanger shown in FIGS. 4 and 5. The heat exchanger shown in FIG. 4 and FIG. 5 is interposed between a large number of tubes (71) made of the above aluminum material for brazing and horizontally arranged in parallel with each other and adjacent tubes (71). A corrugated fin (72) is arranged, and a pair of left and right hollow cylindrical headers (73) (74) are connected to both ends of each tube, and a refrigerant is provided on the upper and lower peripheral surfaces of the left header (73). The inlet pipe (75) and the outlet pipe (76) are connected, and the left and right headers are provided with a partition plate (77) for partitioning the refrigerant circuit into a meandering circuit. The corrugated fin (72) is made of JIS3003 Al alloy and has a thickness of 0.15 mm.
I used the one.

Next, for each of the above heat exchanger assemblies in which no flux was mixed (Sample Nos. 1 to 8), the same suspension of flux as described above was applied and dried, and then one of the fluxes was replaced. Mixture (Sample Nos. 9 to 1)
For 3), without applying the flux suspension,
Heat in a N ₂ atmosphere at 600 ° C for 3 minutes, then use a tube (7
1) with corrugated fins (72), and tubes (71)
The headers (73) (74) and other components were brazed. Here, tube (71) and corrugated fin (72)
Was joined by the sprayed layer on the surface of the tube, and the tube (71) and the headers (73, 74) were joined by a brazing material clad on the inner and outer surfaces of the header.

Then, the brazing property of the tube (71) of each heat exchanger was evaluated by visually observing the joint state with the corrugated fin (72). The results are shown in Table 1.
Shown in.

[0034]

[Table 1]

Sample No. having good brazing property
Each of the heat exchangers 2, 3, 5, 6, 7, 10, 11, and 13 was subjected to a CCT corrosion test (composite corrosion test) to examine the corrosion state of the tube after 180 cycles. It was as it was.

As can be seen from the results in Table 1, when the amounts of Si, Zn, and flux components deposited in the sprayed layer were within the predetermined ranges, excellent brazing properties and excellent corrosion resistance were exhibited, and after brazing. It can be seen that the appearance of is also good.

[0037]

According to the present invention, Al and S for brazing are used.
Al-Si containing both i and Zn for corrosion protection as an alloy
Since the Zn-based alloy powder is sprayed, it is not necessary to sequentially form the anticorrosion layer and the brazing material layer separately, and only one spraying device is required. Therefore, it is possible to manufacture the brazing aluminum material having anticorrosion performance without lengthening the manufacturing line and increasing the cost due to the installation of a plurality of thermal spraying devices.

In addition, since the ratio of the Si component and the Zn component in the Al-Si-Zn alloy does not change before and after the thermal spraying, the ratio of the Si component or the Zn component in the Al-Si-Zn alloy powder as the starting material is changed. By adjusting
The ratio of the Si component and the Zn component in the sprayed layer can be easily and surely realized.

On the surface of the aluminum material, Al-S
Since spraying mixed powder of i-Zn based alloy powder and a flux powder, coating work of the flux during brazing is unnecessary, it is possible to simplify the manufacturing process.

Further, a coating weight of 3 to 10 g / m ² the flux of aluminum material surface, the adhesion amount of Si component of aluminum material surface adhesion amount of 3 to 20 g / m ^2, Zn component 6~14g because it is / m ^2, without causing deterioration of appearance quality due to flux residue can be achieved excellent brazeability, corrosion resistance.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a thermal spraying process in an example.

FIG. 2 is an enlarged cross-sectional view of a main part of FIG.

FIG. 3 is an enlarged cross-sectional view of a thermal spray gun used in an example.

FIG. 4 is a front view of a multi-flow type aluminum heat exchanger manufactured in an example.

5 is a perspective view showing a tube and a corrugated fin of the heat exchanger of FIG. 4 separately.

[Explanation of symbols]

20 ... Aluminum material (aluminum extruded material) 50 ... Sprayed layer

─────────────────────────────────────────────────── ─── Continuation of front page (72) Masahiro Kojima, 6-224, Kaiyamacho, Sakai City, Showa Aluminum Co., Ltd. (56) References JP 61-74771 (JP, A) JP 8-215886 (JP, A) JP 7-314177 (JP, A) JP 7-124787 (JP, A) JP 6-142977 (JP, A) JP 6-23536 (JP, A) Kaihei 5-305492 (JP, A) JP 4-371368 (JP, A) JP 4-75771 (JP, A) JP 3-285761 (JP, A) JP 3-155460 ( JP, A) JP 3-35896 (JP, A) JP 1-107961 (JP, A) JP 63-1152 (JP, B2) JP 6-504485 (JP, A) JP 2500711 (JP, B2) WO 92/12821 (WO, A1) (58 ) investigated the field (Int.Cl. ^7, B name) C23C 4/06 B23K 1/19 B23K 1/20 B23K 35/22 C23F 11/18 C23C 4/00 - 6/00

Claims (2)

(57) [Claims] 1. A surface of an aluminum material is coated with aluminum.
The amount of flux adhered on the material surface is 3 to 10 g / m ² ,
The adhesion amount of Si component on the surface of the minium material is 3 to 20 g /
As the amount of adhering m ^2, Zn component is 6~14g / m ²
And Al-Si-Zn alloy powder and brazing flux
Brazing protection characterized by spraying a mixed powder of powders
Manufacturing method of edible aluminum material. 2. Aluminum on the surface of an aluminum material
The amount of flux adhered on the material surface is 3 to 10 g / m ² ,
The adhesion amount of Si component on the surface of the minium material is 3 to 20 g /
As the amount of adhering m ^2, Zn component is 6~14g / m ²
The Al-Si-Zn alloy powder and the flux powder.
Anti-corrosion alloy for brazing, which is manufactured by spraying a mixed powder.
Luminium material, without applying flux
A brazing method characterized by performing brazing.