JPH04111994A - Wire-or plate-shaped brazing material coated with flux and production thereof and brazing method using this brazing material - Google Patents

Abstract

PURPOSE:To decrease the adhesion quantity of a flux and to prevent dropping of the molten flux at the time of brazing and the remaining of the flux on the surface of joining members after the brazing by using the wire- or plate- shaped brazing material formed with a flux film on the surface. CONSTITUTION:For example, the wire- or plate-shaped brazing material 2 drawn out of a coil 1 is passed into a flux treating chamber 4 and the flux film is continuously formed on the surface of the brazing material passed in this treating chamber and, there, this material is taken up on a coil 3. Since the need for the application of the flux on the joint part is eliminated, the adhesion of a large amt. of the flux to the joint part and the periphery thereof is prevented. The generation of stains and unequal color tones by remaining of the excess flux on an aluminum member after brazing is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a flux-coated wire or plate brazing material made of aluminum or the like, a method for manufacturing the same, and a method for brazing aluminum materials or the like using the brazing material.

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

Conventional technology In general, when brazing automotive radiators, evaporators and condensers for car air conditioners, various aluminum heat exchangers for electrical and industrial use, or aluminum intake manifolds for automobiles, wires are formed at the joints. Alternatively, a method may be used in which a plate-shaped brazing filler metal is placed or a thin plate-shaped brazing filler metal is placed between the joining members, and the constituent members are brazed and joined using flux.

Conventionally, when performing such brazing, first place the flux in water or a solvent! After making it cloudy, this suspension is applied to the surface of the joining member by spraying, showering, dipping, etc., then it is preheated and dried, and then the brazing material is placed and heated in a non-oxidizing atmosphere. Brazing was performed by heating to a predetermined temperature and melting the brazing material.

Problems to be Solved by the Invention However, in the brazing method as described above, since flux is applied to the joining members, a large amount of flux adheres not only to the joining site but also to the surrounding area. This causes problems such as contamination of the inside of the furnace, or situations where the melted flux in the furnace drips and accumulates inside the furnace, making cleaning and overhauling of the furnace more frequent. was there. Furthermore, more flux than necessary will adhere, leading to waste of flux, and excess flux will remain on the surface of the joined parts after brazing, causing gray or white stains, resulting in uneven color tone and appearance. There was a problem in that it not only spoiled the appearance but also interfered with subsequent surface treatment.

This invention was made in view of this technical background, and it is possible to reduce the amount of adhered flux, thereby solving problems such as dripping of molten flux during brazing and flux remaining on the joint surface after brazing. The purpose is to eliminate such problems.

Means for Solving the Problems In order to achieve the above object, the present invention provides a linear or plate brazing material with a flux coating formed thereon, and brazing using this flux-coated brazing material. This aims to eliminate the need to directly apply flux to the joining members.

That is, one of the inventions is a linear or plate-shaped solder with a flux film formed on the surface, and the other one is a
A method for producing a flux-coated linear or plate-shaped brazing material is characterized in that a flux film is formed on the surface of the linear or plate-shaped brazing material by a dry method. This is a brazing method characterized by using a linear or plate-shaped solder on which a flux film is formed, and brazing by arranging the solder in a joint.

The type of flux film formed on the surface of a linear or plate-shaped brazing material is not particularly limited, and the type of flux film formed on the surface of the wire or plate brazing material is not particularly limited. Any material may be used as long as it exhibits the effect of improving wetting and flow. For example, the conventionally used KAρF4, N2 AgF
2. Fluoride-based flux such as K3AΩF6 or a eutectic composition of KF and AΩF3, or chloride-based or bromine-based flux may be used. Further, instead of using only one type of flux, a mixture of two or more types may be used. However, since chloride-based fluxes produce corrosive residues and bromine-based fluxes have safety problems, it is better to use fluoride-based fluxes that do not have such disadvantages. Among them, it is particularly preferable to use KAΩF4, which is easy to evaporate and form a film.

The method for forming the above-mentioned flux film on the surface of a linear or plate brazing filler metal is not particularly limited, and a wet method using a solution containing potassium and fluorine, a flux suspension, etc. is adopted. It's okay. However, it is preferable to adopt a dry method in which the film is formed by a so-called dry process that does not use a suspension or solution. The reason for this is that a drying step after film formation is unnecessary and that the amount of flux film can be reduced to the minimum necessary. As such a dry method, PVD method (Physical Vap
Examples include a physical vapor deposition method, a thermal spraying method, and a film forming method in a flux saturated vapor pressure atmosphere. Further, specific examples of the PVD method include vacuum evaporation method,
Examples include a vapor deposition method in an inert gas such as N2 or Ar, a sputtering method, an ion blating method, and the like. These dry processing methods are well-known methods for forming metal films, but
When applied to the formation of a flux film, flux may be used instead of metal as the film material. A brief explanation of these methods is as follows. First, in the vacuum evaporation method, the temperature inside the flux processing chamber is 104 to 10'T.

After evacuation to about rr, the flux is heated and evaporated from an evaporation source provided in the processing chamber, solidified and deposited on the surface of the linear or plate-shaped brazing filler metal, thereby forming a flux film. As a method for heating and evaporating the flux, resistance heating, electron beam heating, high frequency heating, etc. can be employed.

The inert gas vapor deposition method is a method in which a film is formed by heating and evaporating the flux under a reduced pressure of about 10-4 to 760 Torr or in an inert gas atmosphere set to atmospheric pressure, as in the vacuum vapor deposition method. be. The sputtering method is basically a method in which ions and electrons collide with flux and the ejected flux is deposited on the surface of the brazing material to form a flux film. The ion blating method is essentially the same as the vacuum evaporation method, but by ionizing flux particles evaporated from the evaporation source,
This results in a film with better adhesion. The thermal spraying method is a method in which flux is continuously melted at high temperature and fine particles of the molten flux are sprayed at high speed to form a thermal spray coating on the surface of the brazing material. In addition, in the method of forming a film in a saturated vapor pressure atmosphere, a flux such as KAΩF4 is heated and evaporated in an N2 gas atmosphere to create a mixed gas atmosphere with N2, and a brazing material is placed in this atmosphere to form a film. This is a method of forming. Any of the dry methods described above or other than the above may be used, but from the viewpoint of simplicity of equipment and ease of film formation, it is preferable to use a vacuum evaporation method or an evaporation method in an inert gas.

The amount of the flux film formed on the surface of the linear or plate brazing material is preferably set to about 1 μ'j/crd or more. If the amount of flux is less than 1 μ (j/ctd), the amount of flux is too small, and it may not be possible to exhibit a sufficient flux effect, which may impede good brazing. On the other hand, if the amount of flux film is too large, Excessive flux may cause residual flux on the surface of the soldering material or on the surface of bonding materials such as aluminum, which may cause stains and color unevenness, so use 1000 μg.
It is preferable to set the film amount to about /d or less. Particularly preferably, the range is about 20 to 500 μ3/d. The amount of flux coating can be easily adjusted by increasing or decreasing the amount of flux deposited, sputtered, thermally sprayed, or the like.

The above-mentioned flux film may be formed after the linear brazing material or plate-shaped brazing material is cut into short pieces or after it is formed into a predetermined shape, but it is preferable to form the flux film when the soldering material is in a long shape. It is recommended to form the film during the process because the film can be formed continuously and production efficiency can be improved. As shown in Fig. 1, a method for continuously forming a flux film on a long piece of wax is, for example, a wire or plate brazing filler metal (2) drawn out from a coil (1).
) is passed through a flux processing chamber (4), a flux film is continuously formed on the surface of the passing brazing material within the processing chamber, and the flux film is then wound into a coil (3).

In the same figure, (5) is the evaporation source when the vapor deposition method is adopted as the dry flux film forming method. It is preferable to employ a vapor deposition method or a vapor deposition method under reduced pressure. When the flux film is formed continuously in this way, the amount of the film can be easily adjusted by increasing or decreasing the conveying speed of the brazing material.

In addition, as a more preferable method, when the brazing material is an extruded material, as shown in FIG.
4) to continuously form a flux film within the processing chamber, and then winding the flux into a coil (3).

In this way, by forming the flux film immediately after extrusion, the flux film can be formed while the surface of the brazing material (2) is active, making it possible to form a flux film with even better adhesion. .

Moreover, by forming the flux film immediately after extrusion, the film treatment can be carried out in a series of continuous steps by incorporating it into the extrusion and winding steps, which has the advantage of increasing production efficiency. In FIG. 2, parts with the same names as those shown in FIG. 1 are given the same reference numerals.

Although not shown, by providing multiple processing chambers and multiple evaporation sources, the brazing material can be conveyed so that both sides of the brazing material are exposed to the evaporation source, etc. Alternatively, the flux film can be continuously formed on the entire circumferential surface. In addition, instead of the continuous method, the flux film may be formed in a batch method on short pieces of brazing material or on the brazing material after molding, or by placing the brazing material one after another on a belt conveyor using a mesh belt and fluxing. It may be carried in continuously into the room.

The linear or plate brazing filler metal with a flux film formed on its surface is subjected to shaping processes such as cutting and bending, if necessary. When a flux film is formed by a dry method, the flux film is directly and tightly adhered to the surface of the brazing material, so there is no risk of the film peeling or falling off even when bending is performed. After that, a flux-coated brazing filler metal is placed at the joining part of the bonding members made of aluminum, etc., and then heated to a temperature of about 580 to 620°C, which is higher than the melting point of the flux, to melt the brazing filler metal and achieve a brazed joint. be done. During this brazing process, the flux film formed on the surface of the linear or plate-shaped brazing material effectively exerts a flux action, thereby ensuring good wettability and fluidity of the brazing material, resulting in good brazing. The state is obtained.

Example (Example 1) Thin plates A and Q brazing filler metal made of A4343 wound into a coil were unwound as shown in Fig. 1 until the moisture content was 20.
The brazing material was passed through a flux treatment chamber with a nitrogen atmosphere of ppm, and KAρF4 was vapor-deposited within the treatment chamber to continuously form a KAρF4 flux film on the surface of the brazing filler metal. The amount of flux film was 100 μ9/7.

Next, prepare an A3003AΩ plate and an Al100Aβ extruded tube, and assemble them so that the end of the tube is in contact with the AΩ plate.The above flux-coated brazing material is punched out into a donut shape, passed through the tube, and the tube and AΩ plate are assembled. The brazing filler metal was placed near the contact portion.

(Example 2) A linear AΩ brazing material made of A434B is hot extruded, and immediately after extrusion, it is passed through a flux processing chamber with an atmosphere of 101 Torr, and KAΩF4 is vapor-deposited in the processing chamber. A KAΩF4 flux film was continuously formed on the surface.

Next, as in Example 1, the extruded tube <A1100A, Q was assembled so that its tube end was in contact with the A3003AΩ plate, and the above flux-coated brazing material was cut into short lengths to bring the tube into contact with the Aρ plate. The brazing filler metal was placed near the section.

(Comparative Example) A single-sided AΩ brazing sheet 1 in which one side of an A300B core material was coated with an A4343 brazing material was prepared, and an Al100AΩ extruded tube was assembled on the brazing material layer side of the sheet so that its tube ends were in contact.

On the other hand, a flux consisting of a eutectic composite of KF and AΩF3 was suspended in water to prepare a suspension having a concentration of 5%.

Next, the above assembly was immersed in this suspension to apply flux, and then dried.

The assemblies obtained in each of the above examples and comparative examples were brazed by heating at 600° C. for 5 minutes in a nitrogen atmosphere with a moisture content of 100 ppm and a 02 concentration of ioppm.

When the brazing properties of each of the brazing notes obtained above were examined, they all exhibited a good brazing condition. Also,
Visual observation of the appearance of the solder joint and its vicinity revealed that the product of the present invention had an extremely clean appearance and no residual flux was observed. On the other hand, in the comparative product, uneven gray to white color tone was observed.

Furthermore, residual granular flux was visually observed.

From these results, it was confirmed that not only good brazing was achieved in the product of the present invention using flux-coated wire or plate brazing material, but also that the surface condition of the obtained brazing material was also good. .

Effects of the Invention As described above, the present invention provides a linear or plate-shaped brazing material having a flux film formed on its surface, and brazing is performed by placing this brazing material at a joint. There is an effect like.

In other words, since there is no need to apply flux to the joining parts, it is possible to prevent a large amount of flux from adhering to the joining part and its surroundings, and to clean the furnace to prevent contamination in the brazing furnace or accumulation of flux in the furnace. , the frequency of overhaul can be reduced. Furthermore, since the amount of brazing filler metal used is proportional to the amount of flux used, the amount of flux used can be easily adjusted, and the use of more flux than necessary can be eliminated, thereby eliminating waste of flux. Furthermore, it is possible to prevent stains and uneven color tone from occurring due to excess flux remaining on the surface of the aluminum member after brazing, and to eliminate the risk of interfering with subsequent surface treatment. Furthermore, since flux is always present wherever the brazing material is present, the flux action can be reliably exerted, and the occurrence of brazing defects can be reliably prevented.

We also manufacture flux-coated wire or plate brazing filler metals.
When the dry method is used, in addition to the above-mentioned effects, a drying step after film formation is not necessary, so the working time up to brazing can be shortened and efficiency can be increased. In addition, the amount of flux film can be easily adjusted by adjusting the amount of flux evaporation, etc., so the amount of flux film is the minimum necessary, and the flux cannot be brought into the brazing furnace or bonded after brazing. This has the effect of more effectively solving the problem of residual flux on the surface of the member.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view showing a schematic configuration of a continuous manufacturing method for a flux-coated wire or plate-shaped solder, and FIG. 2 is a schematic front view showing a schematic configuration of another continuous manufacturing method.・Brazing material. that's all

Claims (3)

[Claims] (1) Linear or plate-shaped brazing filler metal with a flux film formed on its surface. (2) A method for producing a flux-coated linear or plate-shaped brazing material, which comprises forming a flux film on the surface of the linear or plate-shaped brazing material by a dry method. (3) A brazing method characterized by using a linear or plate-shaped brazing filler metal having a flux film formed on its surface, and brazing by placing the brazing filler metal at a joint.