JPH09174277A - Composition for brazing aluminum material and aluminum material for brazing and method for brazing aluminum material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to braze aluminum materials at a low cost and obtain a high joining rate and good brazing property. SOLUTION: This compsn. for brazing the aluminum materials is composed by suspending brazing filler metal powder consisting of a metal capable of forming an eutectic alloy with aluminum or an alloy of this metal and aluminum, fluoride based flux powder and polyether based material having a polyoxyethylene chain in water. The first aluminum material and second aluminum material formed with coating layers by applying such compsn. for brazing on their surfaces, then drying the coatings are pressed via the coating layers and are heated in this state, by which the aluminum materials are brazed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a brazing composition for an aluminum material, an aluminum material for brazing, and a brazing method for an aluminum material, and in particular, brazing can be performed at low cost, and a high bonding rate can be obtained. The present invention relates to a brazing technique for an aluminum material that can exhibit good brazing properties.

[0002]

BACKGROUND ART Conventionally, when joining aluminum materials made of aluminum or aluminum alloy by brazing, a method of brazing torch using a brazing wire has been adopted. According to this method, If the shape of the aluminum material to be joined is a simple shape and there are few joining points, it can be handled, but as in the case of brazing the tube material and the fin material forming the heat exchanger, the joining points are In many cases, and when the shape of the aluminum material to be brazed is complicated, it was not possible to cope with it sufficiently.

Therefore, recently, a method using a brazing sheet made by laminating a brazing material to an aluminum material has been proposed. For example, as a method of using this brazing sheet, brazing in a vacuum,
Various brazing methods, such as brazing in an inert atmosphere or brazing with flux,
It has been proposed. More specifically, when brazing a fin material and a tube material constituting a radiator, which is a kind of heat exchanger, the Al-Si alloy brazing material has a thickness of about 10% of the total thickness. Since brazing is carried out by heating the fin material made of rolled aluminum material clad on both sides with (bonded to) the tube material obtained by aluminum extrusion molding, the fin material is heated. is there.

By the way, the method of brazing an aluminum material using such a brazing sheet is effective when there are many joints or when the shape of the aluminum material is complicated, but the brazing sheet is , Because the brazing material is adhered over the entire surface of the base metal, the brazing material is also adhered to the part that is not necessary for brazing, and therefore, it is very wasteful, therefore, It has a problem of high cost. In addition, since the brazing material is also attached to the parts that are not necessary for brazing, when brazing is performed, such extra brazing material erodes the base metal, causing deformation of the base metal. It also has the problem of being done.

Therefore, in order to eliminate such drawbacks, Japanese Patent Publication No. 6-504485 and Japanese Patent Laid-Open No. 6-114.
In Japanese Patent Laid-Open No. 592, etc., a method is proposed in which a brazing composition comprising a mixture of a brazing material powder and a flux powder is applied to the surface of an aluminum material as it is or in a slurry state. Further, according to this method, the brazing material can be applied only to the portion necessary for brazing, so that the cost of the brazing material can be reduced.

However, even with such a method, although the cost can be reduced, there is an inherent problem that the joining rate is lowered or the brazing failure is caused by brazing. More specifically, when the brazing composition is applied as a powder, the brazing composition is apt to scatter, so that the brazing composition is insufficiently applied to an aluminum material. However, there is an inherent risk that the amount of brazing material applied will be insufficient and the bonding rate will be significantly reduced. Further, when the brazing composition is applied in a slurry state, when the slurry is applied to an aluminum material and then dried, the slurry coating layer is easily removed from the aluminum material, and as a result, the brazing composition for the aluminum material is reduced. Uneven application of the attachment composition,
That is, the amount of brazing filler metal applied becomes uneven. Then, when brazing is performed in such a state, the joining ratio is lowered in a portion where the amount of the brazing material is too small, and conversely, when the amount of the brazing material is excessive, the excess brazing material is an aluminum material. Corrosion of the aluminum material reduces the strength of the aluminum material, and buckling is caused by a pressing force applied by a jig or the like that fixes the aluminum material to the portion where the strength is reduced. The attachment becomes defective.

[0007]

The present invention has been made in view of such circumstances, and a problem to be solved by the present invention is that brazing can be performed at a low cost, a high bonding rate, and good brazing. And a brazing aluminum material obtained by treating an aluminum material with the brazing composition, which is capable of exhibiting such characteristics. Another object is to provide a brazing method for aluminum materials.

[0008]

The present invention, in order to solve such a problem, a metal capable of forming a eutectic alloy with aluminum, or a brazing filler metal powder made of an alloy of the metal and aluminum,
The gist is a composition for brazing an aluminum material, which is obtained by suspending a fluoride-based flux powder and a polyether-based substance having a polyoxyethylene chain in water.

In such an aluminum material brazing composition according to the present invention, a metal capable of forming a eutectic alloy with aluminum or a brazing material made of an alloy of the metal and aluminum and a fluoride-based flux are used. Since the brazing composition is contained, the brazing material powder and the flux powder are effectively present in the coating layer formed by applying the brazing composition to an aluminum material and drying it. It becomes. That is, at the time of forming such a coating layer, the aluminum material brazing composition according to the present invention, since the polyether-based substance having a polyoxyethylene chain is added, due to its adhesive properties,
The brazing filler metal powder and the flux powder, which are the essential additive components, can be advantageously fixed and retained on the aluminum material, and therefore the coating layer contains the brazing filler metal powder and the flux powder uniformly, It is formed as a layer having a uniform composition. Moreover,
Since such a brazing composition is applied to a required place in a required amount, the amount used can be advantageously reduced.

Further, according to the present invention, an aluminum material made of aluminum or an aluminum alloy, a brazing filler metal powder made of a metal capable of forming a eutectic alloy with aluminum or an alloy of the metal and aluminum, and a fluoride flux powder. A coating composition containing such a brazing filler metal powder and a flux powder is obtained by applying and drying a brazing composition obtained by suspending a polyether-based substance having a polyoxyethylene chain in water. An aluminum material for brazing, which is formed on the surface of the material, is also included in the gist of the invention.

In such an aluminum material for brazing, a coating layer having a uniform composition containing the brazing material powder and the fluoride flux powder is formed on the surface of the portion to be brazed. Therefore, brazing can be easily performed by heating with other aluminum materials being brought into contact with each other through this coating layer.

Furthermore, the present invention provides a first aluminum material made of aluminum or an aluminum alloy,
A brazing filler metal powder made of a metal capable of forming a eutectic alloy with aluminum or an alloy of the metal and aluminum, a fluoride flux powder, and a polyether substance having a polyoxyethylene chain are suspended in water. A coating layer containing the brazing material powder and the flux powder is formed on the surface of the first aluminum material by applying and drying the brazing composition. In a state where the second aluminum material made of aluminum or an aluminum alloy is brought into contact with the first aluminum material,
A brazing method for an aluminum material, which is characterized in that the first aluminum material and the second aluminum material are brazed by heating, is also the subject of the invention.

In such a brazing method for an aluminum material, a coating layer having a uniform composition containing a brazing filler metal powder and a fluoride-based flux powder is formed on the surface to be brazed. Since a single aluminum material is used, it is possible to advantageously manufacture a high-quality aluminum material brazed product having a high bonding rate and excellent brazability.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION By the way, as a brazing material used in the brazing composition for an aluminum material according to the present invention, a metal capable of forming a eutectic alloy with aluminum during brazing, or the metal and aluminum. Any alloy known in the art can be used as the alloy. Specific examples of such a brazing material include metals such as Si, Zn, Cu, and Ge, and alloys of at least one of these metals with aluminum.

Further, the flux used in the brazing composition for an aluminum material according to the present invention reduces the oxide film formed on the surface of the aluminum material to remove it, thereby forming a eutectic alloy of aluminum and the brazing material. As the flux, any conventionally known flux can be adopted as such a flux, and more specifically, KF- AlF ₃ , KAlF ₄ , K ₂ Al
_{F 5, K 3 AlF 6,} RbF-AlF 3 , etc. can be mentioned. Here, the flux is limited to the fluoride-based flux, because the flux other than the fluoride-based flux, for example, when using the chloride-based flux, because it is easy to cause corrosion of the aluminum material,
This is because after the brazing, a special residue-removing treatment must be performed, and when using a bromide-based flux, there are problems such as a problem in handling safety, which is not preferable. .

Further, the polyether-based substance having a polyoxyethylene chain used in the brazing composition for an aluminum material according to the present invention has an adhesive property, whereby the brazing material and the fluoride are included. Although it is added as a binder for binding and fixing the system flux to the aluminum material, as such a polyether-based substance, various conventionally known compounds having a polyoxyethylene chain (polyethylene glycol chain) Are appropriately selected and adopted, and specifically, higher alcohols, alkylphenols, fatty acids, and the like, polyethylene glycol or polyoxyethylene bound polyoxyethylene ether, polyoxyethylene ester, or polypropylene glycol at both ends of polypropylene glycol. Add weight It is allowed polyoxypropylene polyoxyethylene block copolymers, and the like obtained. In addition, a functional group such as an epoxy group or a carboxy group is introduced into such a polyether-based substance as necessary in order to improve the adhesiveness to the aluminum material.

Here, the polyether-based material is limited to those having a polyoxyethylene chain, which means that the polyether-based material having this polyoxyethylene chain is at a temperature lower than the brazing temperature. In a nitrogen gas atmosphere, it is easily decomposed and burned down, and the ash content becomes 1% or less, which prevents the surface of the aluminum material from being soiled after brazing. , Polyether-based substances having no polyoxyethylene chain, and other adhesive substances are less likely to decompose and burn out at a temperature lower than the brazing temperature in a nitrogen gas atmosphere, and as a result, brazing is difficult. Because it will not work well.

The aluminum material brazing composition according to the present invention contains the brazing powder as described above, a fluoride-based flux powder, and a polyether-based substance having a polyoxyethylene chain in an appropriate amount of water. It can be easily prepared by uniformly dispersing and suspending. The mixing ratio of the fluoride flux powder to 1 part by weight of the brazing material is usually 0.1 to 5 parts by weight, preferably 0.1 to 3 parts by weight. This is because, if the blending ratio is less than 0.1 parts by weight, the effect of the flux cannot be sufficiently exerted, and if the blending ratio is more than 5 parts by weight, more than This is because the effect of using the flux is not obtained. The blending ratio of the polyether-based substance having a polyoxyethylene chain to 1 part by weight of the brazing filler metal is usually
The amount is 0.1 to 10 parts by weight, preferably 0.1 to 3 parts by weight. This is because, if the blending ratio is less than 0.1 parts by weight, the effect of binding and fixing the brazing material and the fluoride-based flux to the aluminum material is insufficient, and the blending ratio is This is because if the amount is more than 10 parts by weight, further bonding and fixing action cannot be obtained. Further, the amount of water is not particularly limited, but is appropriately adjusted so that the brazing composition has an appropriate viscosity for application.

The aluminum material for brazing according to the present invention uses the above-mentioned brazing composition for aluminum material, and an appropriate amount of the composition is applied to a predetermined portion of the aluminum material made of aluminum or aluminum alloy to be brazed. By doing so, it can be easily obtained. More specifically, as the aluminum material to be brazed, any material can be used as long as it is usually used for brazing an aluminum material made of aluminum or an aluminum alloy, and the surface of such an aluminum material can be used. Then, the composition for brazing an aluminum material as described above is applied and then dried. The coating amount of the brazing composition to the aluminum material is a brazing material amount, usually a 1g / m ² ~100g / m ² approximately, the application method, if it is possible to uniformly apply any Even if it is applied by a method, there is no problem, and for example, a brush application method, a spray application method, a roll application method, or the like can be used. The drying treatment performed after applying the brazing composition is to evaporate and remove water as a dispersion medium, and may be performed according to various known methods, for example, at about 120 ° C. Techniques such as heating and drying under temperature conditions are adopted.

Further, in the brazing method of the aluminum material according to the present invention, the above-mentioned brazing aluminum material is used, and the brazing aluminum material and the aluminum or aluminum alloy to be joined are the first By brazing the two aluminum materials according to the usual method, the two aluminum materials can be brazed advantageously. That is, as described above, the first aluminum material having a coating layer of uniform composition containing a brazing material and a fluoride-based flux is formed on the surface of the portion to be brazed, A predetermined second aluminum material is abutted through the layer,
By heating in the same manner as before, the desired brazing product can be advantageously manufactured with a high bonding rate and with excellent brazing properties, and thus as a high-quality product without problems such as erosion and buckling. Of.

[0021]

EXAMPLES In order to clarify the present invention more specifically, some examples of the present invention will be shown below.
It goes without saying that the present invention is not subject to any restrictions by the description of such embodiments. In addition, in addition to the following examples, the present invention, in addition to the above-described specific description, various changes, corrections, and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that improvements can be made.

First, various brazing filler metals, a fluoride-based flux, and a polyether-based substance having a polyoxyethylene chain were added to water at the compounding ratio (weight ratio) shown in Table 1 below, and they were added. The aluminum material brazing compositions of Examples 1 to 7 of the present invention were prepared by mixing and dispersing. As the brazing material, silicon powder (Si),
Powder composed of an alloy of silicon and aluminum (Al-
12% Si) or zinc powder (Zn) is used, and as the fluoride-based flux, KAlF ₄ powder and K _{3 are used.}
A mixture of AlF ₆ powder and a powder of 32:68 (weight ratio) was used. Furthermore, as the polyether-based substance having a polyoxyethylene chain, polyoxyethylene (16) nonylphenyl ether (Adecatol NP-760: manufactured by Asahi Denka Kogyo Co., Ltd.) or polyoxypropylene / polyoxyethylene block copolymer ( ADEKA Pluronic F-88: manufactured by Asahi Denka Kogyo Co., Ltd. was used.

[0023]

[Table 1] A: polyoxyethylene (16) nonylphenyl ether B: polyoxypropylene / polyoxyethylene block copolymer

For comparison, without using a polyether type substance having a polyoxyethylene chain, 1 part by weight of silicon powder as a brazing material and 3 parts by weight of fluoride type flux powder should be mixed. The aluminum material brazing composition (mixed powder) of Comparative Example 1 was prepared. As the fluoride-based flux, a mixture of KAlF ₄ powder and K ₃ AlF ₆ powder at a ratio of 32:68 (weight ratio) was used, as in the above-described example of the present invention.

Then, the various brazing compositions for aluminum materials thus obtained are applied to the aluminum material to form a coating layer having a uniform composition on the surface thereof, and then the coating layer is interposed. Then, brazing was carried out by heating while keeping another aluminum material in contact. More specifically, an aluminum alloy: JIS-A1050 is extruded to form a brazing material on the surface of a tube material (shaped material), and the brazing material content is 5 g / m ^2. As described above, each of the various brazing compositions for aluminum materials was applied, and then heated and dried at 120 ° C. to form a coating layer containing a brazing material and a flux. However, when the aluminum material brazing composition of Comparative Example 1 was applied, a coating layer (coating layer) was formed by coating the aluminum material brazing composition as a powder. Then, through this coating layer, an aluminum alloy plate: JIS-A30
The fin material obtained by processing 03 into a corrugated shape was brought into contact with it, and in that state, it was heated to 600 ° C. in a nitrogen gas atmosphere for 30 minutes and held at that temperature for 3 minutes. The aluminum materials (tube material + fin material) were brazed by cooling.

After the brazing, the joining ratio and brazing property at the joint between the tube material and the fin material were investigated, and the results are shown in Table 2 below. The joining rate is a percentage of the number of joined portions per 100 joined portions. In addition, the brazing property is that a fillet is formed in the joint portion and a metallic bond is made in the cross-sectional structure,
Moreover, the aluminum material which was not corroded by the brazing material and which did not buckle was evaluated as ◯, and the other material was evaluated as x.

[0027]

[Table 2]

As is clear from the results shown in Table 2, when the aluminum material brazing composition according to the present invention is used to braze an aluminum material,
The high bonding rate and the excellent brazing property can be advantageously exhibited. On the other hand, when using the aluminum material brazing composition of Comparative Example, when brazing the aluminum material, since it is difficult to uniformly apply the brazing material and the flux, the bonding rate is low, and in some cases, Buckling occurred due to an excessive amount of brazing material applied, resulting in poor brazing properties.

[0029]

As is apparent from the above description, the aluminum material brazing composition according to the present invention requires only a necessary amount of brazing material for the intended brazing site. The cost of the brazing material can be advantageously reduced, and the brazing of the aluminum material can be advantageously realized with a high joining rate and an excellent brazing property.

In addition, the flux added to the aluminum material brazing composition according to the invention is
Since it is a fluoride-based flux, it has an advantage that no special removal treatment is required. Moreover, although the aluminum material brazing composition according to the present invention contains a polyether-based substance having a polyoxyethylene chain, the polyether-based substance having such a polyoxyethylene chain is contained in a nitrogen atmosphere. In the brazing operation, it is easily decomposed and burnt down, and the ash content becomes 1% or less, so that it also has an advantage that it does not cause a problem of surface contamination of the aluminum material after brazing.

The brazing aluminum material according to the present invention can be easily obtained by applying the above-described excellent brazing composition for aluminum material to the surface of the aluminum material and drying the composition, and According to such an aluminum material for brazing, since it has a coating layer of a uniform composition containing a brazing material and a flux, a high joining rate and an excellent brazing are achieved when brazing. The sex can be effectively exhibited.

Further, according to the brazing method for an aluminum material according to the present invention, the aluminum material can be joined at a low cost and at the same time, a high joining rate and an excellent brazing property can be realized. A brazing product of good quality aluminum material can be produced advantageously.

Claims (3)

[Claims] 1. A brazing filler metal powder made of a metal capable of forming a eutectic alloy with aluminum or an alloy of the metal and aluminum, a fluoride flux powder, and a polyether substance having a polyoxyethylene chain, A brazing composition for an aluminum material, characterized by being suspended in water. 2. An aluminum material made of aluminum or an aluminum alloy, a brazing filler metal powder made of a metal capable of forming a eutectic alloy with aluminum or an alloy of the metal and aluminum, a fluoride flux powder, and polyoxyethylene. A brazing composition obtained by suspending a polyether-based substance having a chain in water is applied and dried to form a coating layer containing the brazing material powder and the flux powder on the surface of the aluminum material. An aluminum material for brazing characterized by being formed. 3. A first aluminum material made of aluminum or an aluminum alloy, a braze powder made of a metal capable of forming a eutectic alloy with aluminum or an alloy of the metal and aluminum, and a fluoride flux powder. Applying a brazing composition obtained by suspending a polyether-based substance having a polyoxyethylene chain in water,
By drying, a coating layer containing the brazing material powder and the flux powder is formed on the surface of the first aluminum material, and the aluminum is applied to the first aluminum material through the coating layer. Alternatively, brazing of the first aluminum material and the second aluminum material is performed by heating in a state where the second aluminum material made of an aluminum alloy is brought into contact with the first aluminum material and the second aluminum material. Method.