JPH03118966A - Vapor phase brazing apparatus - Google Patents

Abstract

PURPOSE:To stably enable brazing by heating flux to the specific temp. in a flux vapor generator arranged out of a brazing furnace to generate the flux vapor and introducing this to joining position of a member to be brazed in the furnace. CONSTITUTION:In the flux vapor generator 3 arranged out of the brazing furnace 2, the flux 12 having m.p. mp, is heated to >=(mp-50) deg.C with an electric heater 14 to generate the vapor. The generated vapor is mixed with non-oxidized gas introduced from an introducing tube 15 in flowing passage of a guide tube 4 and guided into the brazing furnace 2 as the mixed gas. The mixed gas is fed to near the members 9... to be brazed through branch pipes 16 and acts on the joining position, and under the condition, the joining position between an Al material 9a and brazing material 9b can be brazed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vapor phase brazing apparatus for brazing aluminum or aluminum alloy (hereinafter simply referred to as aluminum) materials.

(Prior Art) Normally, when manufacturing aluminum products by brazing, the assembly is fixed to the parts to be joined via a brazing material with a relatively low melting point, and this is charged into a heating furnace. The products are bonded by heating to a temperature higher than the melting point of the brazing filler metal and lower than the melting point of the aluminum, which is the part to be joined. Aj2-3t alloy is generally used as the brazing filler metal, and if necessary, a small amount of other elements such as Mg may be added.

As conventional brazing methods, flux brazing, which uses flux to remove the oxide film on the surface of the parts to be brazed, and vacuum brazing, which does not use flux, are usually used.

Vacuum brazing is a method of placing the assembly to be joined in a vacuum and applying brazing heat.It has characteristics such as a good surface of the parts after brazing, but it requires a heating furnace that can provide a high vacuum. There are problems such as necessity and material limitations.

Flux brazing properties include furnace brazing properties, in which the assembly to be joined is immersed in molten chloride flux or fluoride suspended in water, and then brazed and heated. However, since chloride-based flux is corrosive to A2, it must be completely removed by cleaning the wax bone, making the manufacturing process very complicated. In addition, as a flux to eliminate this problem,
As described in Publication No. 27037, KAJ2F4 and K x A Q, which are non-hygroscopic and non-corrosive to
There is a mixture of F a, which has the characteristic that it is a non-corrosive flux and does not require post-treatment to remove the flux.

The brazing process used in this brazing method using fluoride flux follows the process diagram shown in Figure 5, and the inside of the brazing furnace is usually in a nitrogen gas atmosphere with a dew point of -40°C. The atmosphere is adjusted to have an oxygen partial pressure of about 200 ppm or less.

The brazing process shown in FIG. 5 is carried out using a brazing furnace as shown in FIG. In the figure, 41 is a brazing furnace, which has a brazing zone in the center, a preheating zone on the left, and a cooling zone on the right. In addition, an inlet 42 and an outlet 43 are provided on both left and right walls of the brazing furnace.
A metal curtain 44a is provided in the preheating zone near the entrance, while a metal curtain 44b is provided in the cooling zone near the exit 43. A belt conveyor 45 is installed in the furnace between the population 42, the preheating zone, the brazing zone, the cooling zone, and the outlet 42, and a covering brazing member 46 is placed on this conveyor.

Further, an electric heater 47 is provided on the rear wall of the preheating zone, and an electric heater 48 and a gas supply port 49 are provided on the rear wall of the brazing zone. Note that 50 is an exhaust pipe that communicates with the preheating zone, brazing zone, and cooling zone.

In the conventional furnace described above, nitrogen gas is supplied from the gas supply port 49 to replace the atmosphere in the furnace with nitrogen gas, and then the member 46 to be brazed coated with flux is transferred to the belt conveyor 45.
into the furnace through the inlet 42. Thereafter, the parts to be brazed are dried in a preheating zone and then transported to a brazing zone where brazing is performed. After that, it is transported to a cooling zone and cooled to around 300 to 450'C, and then transported out of the furnace through the outlet 43. The gas generated from the flux in the brazing zone is collected together with nitrogen gas out of the furnace through the exhaust pipe. Note that the arrows indicate the flow of gas.

(Problem to be Solved by the Invention) However, as shown in FIG. 5, the method using flux described above necessarily requires a coating and drying process to adhere the flux to the surface of the assembly. Furthermore, the applied flux often falls off from the assembly while the assembly is being transported to the next process (thus, the yield of effectively used flux is low. Also, the yield of the flux that is effectively used is low. Since flux residue remains unevenly on the surface, the surface becomes dirty compared to vacuum brazing, and its commercial value is inferior. In addition, chromate treatment and black painting treatments, etc. performed in the post-brazing process to improve corrosion resistance, are required. This resulted in non-uniformity and the effect was not fully exhibited.

Furthermore, flux residue is non-conductive, so when using a corrosion prevention method that protects the tube body with sacrificial material, etc. in a heat exchanger, for example, the flow of anticorrosion current is obstructed, making it impossible to obtain a sufficient corrosion protection effect. There are cases.

Furthermore, when brazing a Mg-containing H8 alloy in a furnace using a fluoride-based flux, the brazing performance is inferior to that of other fluxes, so in order to obtain industrially stable brazing performance, Mg The content of must be less than 0.6 wt%. For Aρ gold alloys that contain more Mg than this, even if a large amount of flux is applied, it becomes difficult to braze.The reason for this is that the Mg in the Aρ alloy reacts with the flux during the brazing heat. As a result, the composition of the flux changes and its effectiveness as a flux is lost. AI2. Mg in the alloy diffuses into the surface layer and the Mg in the surface layer
This is because the g concentration increases and phenomena such as the flux entering the surface layer of the A2 alloy occur, which obstructs the flow of the solder. The fact that A2 alloy with such a high Mg content cannot be used as a material for heat exchangers is a major obstacle in terms of durability and weight reduction of heat exchangers.

As a brazing method that solves the problems with brazing methods that use these fluoride-based fluxes, the present inventors have developed a vapor phase brazing method that does not require the process of directly applying flux to the assembly to be brazed. developed and proposed a law (
(Patent Application No. 1983-298414). This brazing method is characterized by brazing the wax bone component in a non-oxidizing atmosphere in the presence of vapor containing fluoride and/or its complex, so that the surface of the wax bone connection is clean. be. It has features such as low cost because flux application and drying steps are not required.

However, as shown in Fig. 6, conventional brazing furnaces perform brazing by applying flux, and are naturally unsuitable for the method of using flux as steam, as shown in Figure 6. However, there were problems such as the inability to maintain an atmosphere even if the brazing method was used, which was an obstacle to adopting this brazing method.

The present invention has been made for the purpose of providing a brazing device that solves the problems of the prior art described above.

(Means for Solving the Problems) When using flux vapor, the present inventors, as a result of various studies, installed a flux vapor generator outside the furnace, carried this flux vapor in non-oxidizing gas, and carried it inside the furnace. By directing the fluid to the bone and ejecting it to the fistula joint site,
It is possible to constantly control the flux vapor partial pressure in the mixed gas in the atmosphere near the joining area, and to keep the mixed gas blowing pressure and amount and flow in the furnace constant so that the gas flow in the furnace is constant. Based on this finding, the present invention was completed.

That is, the present invention provides (1) a brazing device for brazing aluminum or aluminum alloy materials with a brazing filler metal, which heats a flux having a melting point of m outside a furnace to a temperature of (m p-50)°C or higher; A flux steam generation device that generates steam is installed, and a passageway is provided for transporting the flux steam generated by the device while being supported by non-oxidizing gas, and a passageway for transporting the flux steam generated by the device, and a joint site of the covered bone members in the furnace. and (2) a vapor phase brazing apparatus characterized by being provided with a means for guiding and blowing out air (referred to as the first invention); The present invention provides a vapor phase brazing apparatus (referred to as a second invention) according to claim 1, characterized in that an exhaust device is provided.

Next, embodiments of the present invention will be described in more detail based on the drawings.

FIG. 1 is a schematic diagram showing an example of the vapor phase brazing apparatus of the present invention. In the figure, 1 is a vapor phase brazing device, which is a brazing furnace 2.
, a flux steam generator 3, and a conduit 4 that connects these and guides flux steam and non-oxidizing gas into the furnace.

First, a brazing zone is formed in the center inside the brazing furnace, and metal curtains 5a are provided on both sides of the brazing zone.

5b is provided. And this metal curtain 5a
A heating zone is formed to the left of the metal curtain 5b, and a cooling zone is formed to the right of the metal curtain 5b. Furthermore, a lower outlet 6 and an outlet lower are provided at the lower portions of both side walls of the brazing furnace, and a belt conveyor 8 is provided over the areas of the inlet, heating zone, brazing zone, cooling zone, and outlet lower. A brazing bone member 9 is placed on this belt conveyor 8, and this member 9 is made of an An alloy material 9a and a brazing material 9b interposed at the joint thereof. Note that an electric heater 10 is provided on the rear wall of the heating zone, and an electric heater 11 is provided on the rear wall of the brazing zone.

The flux steam generator 3 includes a container 13 containing flux 12 and an electric heater 14 installed at the bottom of the container.
A non-oxidizing gas introduction pipe 1 is installed on the side wall of this container 13.
One end of 5 is connected.

The conduit 4 has one end connected to the upper end of the container 13, and the other end branched into a branch pipe 16 extending from the upper end of the brazing furnace to above the brazing zone in the furnace and containing a plurality of blowout holes L6a16a... are doing. In the present invention, the mixed gas flow path is appropriately heated and kept warm.

Brazing is performed in the vapor phase brazing furnace having the above configuration, but first, prior to brazing, non-oxidizing gas is introduced into the furnace through the non-oxidizing gas introduction pipe 15 via the flux generator 3 and the gas conduit 4. However, as such a non-oxidizing gas, for example, nitrogen gas, argon gas, -carbon oxide gas, or a mixed gas thereof is used. It is preferable that these non-oxidizing gases be constantly preheated to 600° C. by installing a heater or the like in the conduit 4. On the other hand, communication holes 17a and 17b are provided at the upper ends of the metal curtains 5a and 5b, respectively, and exhaust pipes 18 are provided at the upper ends of the heating zone and the cooling zone, respectively.
a and 18b are connected, and non-oxidizing gas is recovered from inside the furnace through these communication holes and discharge pipes.

During brazing, the brazed bone member is conveyed into the furnace by the belt conveyor 6 in a state in which the non-oxidizing gas replaces the atmosphere in the furnace. First, it is conveyed to the heating zone and heated by the electric heater 10 to preferably 590~ It is heated to 610°C and then transported to the brazing zone.

On the other hand, in the flux steam generator 3, the flux 12 is preferably heated to 450 to 600°C by an electric heater 14 to generate steam. The generated steam is mixed with a non-oxidizing gas introduced from the introduction pipe 15 through the flow path (arrow) of the conduit 4, and is led into the brazing furnace as a mixed gas. This mixed gas is carried by the branch pipe 16 to the vicinity of the covered brazing bone member 9, acts on the joint part, and in this state it becomes possible to braze the joint part of the Aj2 material 9a and the brazing material 9b. The brazing time is not limited as it varies depending on the type and size of the brazing bone component, the number of joining parts, etc., but is preferably 1 to 10 minutes.

Fluorides, chlorides, etc. may be used as the fluxes that generate the above-mentioned vapor.

The fluoride is generally a potassium fluoroaluminate complex, and its specific chemical formula is KAj2F4.
Km General formula K such as AIF6 and KsAβF0. AnF,
, , and mixtures thereof, including KAI2F4+ and AIF.

・Includes mixtures such as H2O. Furthermore, it is also possible to mix solid KF and AIF3, which are the usual raw materials for producing the above-mentioned compounds, or to separately feed them into a furnace to generate steam. ZnCj as chloride
22. There are chlorides of alkali metals such as KCA, LiCj2, and NaCn, and it is also possible to mix these fluorides and chlorides.

Since these fluxes usually melt at around 300 to 600°C, it is necessary to use mixtures containing these fluxes in steam generators at temperatures below 50°C, that is, at 25°C.
It is necessary to have means for heating to 0 to 550°C or higher. The device shown in Figure 1 uses an electric heater as the heating means, and although there are no particular restrictions on the heating means, it is necessary to keep the steam non-oxidizing, so direct heating with combustion gas etc. is not recommended. Electrical or indirect heating is preferred as it makes it easier to control the atmosphere. The method to be used should be determined based on the furnace capacity, operating rate, etc., so that the thermal efficiency and cost are most favorable.

As mentioned above, when the melting point of the flux is m, (
Flux vapor is obtained by heating the flux to m, -50)'C. The reason for specifying the heating temperature for generating steam from flux is that when flux is heated, steam is generated from the solid by sublimation even below the melting point, but the amount of steam generated starts to increase significantly from (m p -50). By exceeding the melting point and becoming molten, the amount of steam generated further increases. At temperatures below (mp-50)°C, the amount of steam generated by sublimation is small and the objective cannot be achieved. The higher the heating temperature, the greater the amount of steam generated.
610°C, and the melting start temperature of aluminum, which is the overlying brazing frame member, is approximately 660°C or lower, so blowing steam significantly higher than these temperatures into the brazing furnace will cause damage to the brazing furnace. This is not preferable as it may cause temperature non-uniformity. Therefore, it is preferable to adjust the heating temperature when the steam is generated so that the temperature when the steam reaches the covered wax bone member is 650° C. or lower.

In addition, in the present invention, by arranging such a steam generator outside the furnace, the steam generation amount can be easily controlled. If the steam temperature is higher than that in the brazing furnace, e.g.
It is possible to reach temperatures up to 1000°C, which allows for efficient steam generation and control of steam concentration, while also making it possible to easily create a steam atmosphere with a higher concentration during brazing, which improves brazing properties. results in an improvement in Furthermore, it is also possible to control the temperature inside the furnace by blowing high-temperature steam into the furnace. Of course, it is also possible to blow steam at 650° C. or lower into the furnace and heat it up to the brazing temperature in the furnace.

Further, the flow path of the gas conduit 4 is preferably as short as possible in order to prevent the temperature of the generated steam from decreasing. Therefore, it is also possible to install the generator directly outside the furnace body. In addition, when the flow path becomes long, it is preferable to take measures such as heat insulation and heating as necessary. It is also possible to utilize this flow path to heat the steam to a higher temperature than the temperature at the time of generation and guide it into the brazing furnace.

It is necessary to maintain a non-oxidizing atmosphere containing flux vapor in the area to be brazed. Specifically, during brazing, the steam partial pressure should be approximately 0.05 to 250 mmHg, the oxygen partial pressure should be 1 mmHg or less, and the water vapor partial pressure should be maintained. It is desirable to keep the temperature below 5 mmHg. Flux vapor is 0. O5mmH
If it is less than g, a sufficient atmosphere will not be formed in the brazed area,
There is a high risk of brazing failure. If the flux vapor partial pressure exceeds 250 mmHg, the flux will not only be wasted (but also the amount of residual flux in the brazed area will increase, impairing the corrosion resistance of the brazed bone component, and if Mg is included in the material) In this case, the reaction between the flux and Mg becomes significant and inhibits brazing properties.

The means for controlling the amount of steam generated in the furnace of the present invention includes the above-mentioned steam generator and the means for introducing an atmospheric gas containing steam to the covering fissure bone member. It is preferable to control the amount of atmospheric gas, etc. After brazing is completed, the brazing bone members 9 are transported to a cooling zone, where they are
The product may be cooled to 00 to 400°C, then transported from the outlet lower to the outside of the furnace, cooled in the atmosphere to room temperature, and transported to the next step. Next, FIG. 2 is a schematic diagram of a vapor phase brazing apparatus showing an example of the second invention. A vacuum evacuation device 22 is connected to the furnace 20 via a connecting pipe 21. Reference numeral 22a is a valve.Other than the above, the structure is almost the same as that of the device shown in FIG.
3 is a flux steam generator, 24 is an electric heater, 2
5 is a non-oxidizing gas introduction pipe, 26 is a flux, 28 is a container, 28a is a valve, 28 is a guide pipe, 29 is a branch pipe, 3
0 is a covering bone member, 31 is an electric heater, and 32 is an entrance/exit.

In addition, in the second invention, the inside of the furnace is first made into a vacuum, and when the furnace is made into a vacuum state, the degree of vacuum is the residual gas pressure.
It needs to be less than or equal to r.

If a gas of 10 torr or more remains (the main gas is the atmosphere in most cases), if the atmosphere is replaced with a non-oxidizing atmosphere containing flux vapor, the atmosphere inside the furnace, and even the brazed area that is close to a blockage situation, will be reduced. The atmosphere may not be sufficiently replaced with a non-oxidizing atmosphere, and good brazing may not be possible. It is desirable for the degree of vacuum in the vacuum state to be high (low residual gas pressure), and its upper limit (
There is no limit to the lower limit of residual gas, but creating an ultra-vacuum requires large-scale equipment (and the time required for evacuation is long, making it inefficient. At production level, 10-' to 10 tor
A degree of vacuum (residual gas pressure) of approximately r is desirable. There are no particular restrictions on the type of equipment used to obtain this degree of vacuum, but generally a rotary pump is used as the main evacuation device, and a diffusion pump or the like may be used as an auxiliary means.

(For A) As described above, in the vapor phase brazing apparatus of the first invention, flux vapor is generated from the flux vapor generator 3 provided outside the brazing furnace, and this is introduced into the flux generator. By supplying a non-oxidizing gas through the gas conduit 4 from the inlet of the furnace through the heating zone to the joining area of the brazing bone member 9 introduced into the brazing zone, this area will be kept in a non-oxidizing atmosphere. Brazing can be carried out in a state suitable for bonding.

The brazing cycle using the brazing device of the second invention is as follows:
First, the brazing bone parts are charged into a furnace, and then preheated or evacuated without heating, and then heated to the brazing temperature, or non-oxidizing gas containing flux vapor is introduced into the furnace during heating. The atmosphere inside the furnace is replaced by introducing
Brazing is commonly performed. For wax bone grafting, the wax bone component is removed and cooled in the atmosphere. Note that other conditions can be carried out in the same manner as in the first invention.

In addition, in the vapor phase brazing apparatus of the second invention, the non-oxidizing gas and flux vapor are introduced into the furnace with the inside of the brazing furnace having an airtight structure evacuated by the vacuum evacuation device. A positive atmosphere is formed at the joining site of the covered wax bone component, and brazing can be performed even in a site close to a closed space, in a state suitable for brazing.

In the above atmosphere, a very small amount of flux vapor adheres uniformly to the assembly (fixed bone component), and the A2
Since it destroys the oxide film of the solder, it promotes the leakage of molten brazing metal to the parts to be welded, thereby forming a uniform fillet at the joint part, making it possible to stably braze the parts to be brazed. . Furthermore, the flux vapor combines with moisture and oxygen in the atmosphere to make the atmosphere more non-oxidizing and has the effect of preventing oxidation of the material surface other than the bonding site.

In the first invention, the flux vapor that has not adhered to the part of the endophytic bone member is transferred to the communication hole 17a, together with the non-oxidizing gas.
It flows out from 17b and is discharged from discharge pipes 18a and 18b, and in the second invention, it is discharged by a vacuum evacuation device for each cycle.

In the first invention, the brazed brazing bone member that has been completely brazed is taken out from the outlet lower via the cooling zone, and in the second invention, it is taken out from the outlet 3.
taken out from 2.

(Example) Next, the present invention will be explained in more detail based on examples.

First, as shown in FIGS. 3(a) and (b), JISA1050 (Ag material with Ag purity of 99.5% by weight or more, hereinafter "% by weight" is simply written as %) was hot-tube extruded into a tubular shape using a conventional method. The meandering pipe material 33 is bent into a meandering shape.
A corrugated fin 34 is made of a plating sheet with a thickness of 0.16 mm in which Al1-1%Mn-L%Zn alloy is used as the core material and Ag-10%5L-1%Zn alloy skin material is clad on both sides. and then add /1-4% Zn-
A connector 35 made of 0.8% Mg is attached and JIS 4047 (Afi-11 to 13% Si) is attached to this joint.
A serpentine-type capacitor was assembled by winding a wire with a wire diameter of 1.6 mm. Note that 36 indicates a bent portion.

Brazing was performed using the apparatus shown in FIG. 1 as a brazing bone member covering the capacitor.

Fluoride KAβF4 is used as the flux 12, heated to 600°C in a non-oxidizing atmosphere of nitrogen gas in the flux generator 3 to melt it, and the generated vapor is passed through a flow path together with the nitrogen gas. It was led to a furnace. The fluoride was heated by heating nitrogen gas to a high temperature (600 to 800°C) and blowing it into the apparatus 3. The flow path of the guide tube 4 is heated by an electric heater, and the gas temperature in the flow path is increased to 600±10℃ by indirectly heating the gas inside the flow path.
It was adjusted so that The mixed gas has a fluoride vapor partial pressure of 5
0mmHg, oxygen partial pressure 1mm/day or less, water vapor partial pressure 5m
Adjusted to below mHg. The flow rate of the gas was controlled by adjusting the nitrogen gas pressure and flow, and the mixing ratio of nitrogen gas and fluoride vapor was controlled by changing the amount of generated steam by adjusting the heating temperature.

The brazing zone is maintained at 610°C, and after the atmosphere in the furnace has been sufficiently replaced with a mixed gas, the condenser is charged by the belt conveyor 8, and the brazing parts to be covered are heated to 59°C in the heating zone.
After heating to 0-610°C, it was charged into a brazing zone. Brazing was carried out by passing through a brazing zone for 5 minutes, then cooling to around 300 to 450°C in a cooling zone, and then cooling to room temperature in the atmosphere. Note that both the heating zone and the cooling zone were in a nitrogen gas atmosphere.

Brazed component (condenser) brazed as above
The sample was taken out of the furnace and the appearance of the surface was observed, and the brazing condition was also investigated, and the results are shown in Table 1. Thereafter, chromate treatment and black painting were carried out by a conventional method, and the adhesion properties thereof are also listed in Table 1 as chromate property and paintability. In addition, in order to evaluate the corrosion resistance of the capacitor after painting, the CASS test was conducted at 50% based on JIS H8681.
The test was carried out for 0 hours to check for the presence of through pitting corrosion, and the results are also listed in Table 1.

Example 2 Using the apparatus shown in FIG. 2, brazing was performed using the same capacitor as in Example 1 as a brazing member.

A mechanical booster and a rotary pump were used as the evacuation device 22, and the brazing furnace 20 was evacuated from above.

Using fluoride KAJ2F as flux 26,
It was heated to 600° C. in a non-oxidizing atmosphere of nitrogen gas in the flux generator 23 to bring it into a molten state, and the generated steam was led to a brazing furnace through a channel together with the nitrogen gas. To heat the flux, use nitrogen gas at a high temperature of 1 (500 to 800
The fluoride was heated by blowing it into the apparatus 23 at a temperature of 0.degree. The temperature of this nitrogen gas was controlled at 600-800°C when the flux was in a solid state, and at 500-600°C after the flux was melted.

The flow path of the conduit 28 was heated by an electric heater, and by indirectly heating the gas in the flow path, the temperature of the gas was adjusted to be constant. The mixed gas has a fluoride vapor partial pressure of 50 mm.
Hg, oxygen partial pressure 1mmHg or less, water vapor partial pressure 5mmHg
Adjusted as below. The flow rate of the gas was controlled by adjusting the nitrogen gas pressure and flow rate, and the mixing ratio of nitrogen gas and fluoride vapor was controlled by changing the amount of generated steam by adjusting the heating temperature. The brazing furnace 20 was an electric furnace, and the mixed gas was passed through a branch pipe 29 in the upper part of the brazing furnace, and the mixed gas was uniformly introduced to the member 30 to be brazed from the upper part.

During brazing, the member 30 to be brazed is charged into a brazing furnace at room temperature, the valve 21a is opened, the valve 28a is closed, and the rotary pump is operated to exhaust the temperature to 10-'' torr.Then, the valve 21a is closed. The thermocouple placed near the brazing material was heated in a vacuum state, and the thermocouple was heated to 450
When the temperature reached 5.degree. C., the valve 28a was opened and the above-mentioned mixed gas was heated to 5.0.degree. C. and introduced into the furnace. After the atmosphere in the furnace was sufficiently replaced with the mixed gas, it was heated to 600±10° C., held for 5 minutes, the valve 28a was closed, and the member to be brazed was taken out of the furnace and cooled to room temperature.

The above brazed members were subjected to the same tests as in Example 1, and the results are shown in Table 1.

For comparison with the conventional example, the characteristics of the capacitor assembly shown in FIG. 3, which was brazed using the conventional method, were investigated.

That is, after degreasing the assembly shown in Fig. 3 with an organic solvent, 10% concentration of KAI;! , apply F4 suspension 20
Drying was performed at 0°C for 10 minutes. Then water vapor partial pressure 5
In the electric furnace shown in Fig. 6, which was purged with a nitrogen gas atmosphere with an oxygen partial pressure of 1 mmHg or less and maintained at 610°C,
This assembly was inserted and heated at 610° C. for 5 minutes to perform brazing.

As in Example 1.2, the appearance was observed, the brazing condition was examined, and the paintability and corrosion resistance were evaluated, and the results are shown in Table 1.

(Comparative Example) The condenser assembly shown in FIG. 3 was subjected to vapor phase brazing using a conventional furnace. KAnF as a source of steam
4 was placed on a flat plate and placed beside the assembly and transported into the brazing furnace at the same time as the assembly. The amount of flux is the flux vapor partial pressure that can be placed in the furnace atmosphere when the entire amount is evaporated6
It was adjusted to be 0 to 1OOmmHg or more. The assembly transported into the furnace is heated at 30°C in the preheating chamber of the brazing furnace as shown in Figure 6.
After heating to 0°C, the atmosphere was replaced with a nitrogen gas atmosphere with a water vapor partial pressure of 10 mmHg or less and an oxygen partial pressure of 5 mmHg or less.
The material was transferred to a brazing zone maintained at .degree. C., and brazed by heating at 610.degree. C. for 5 minutes.

The capacitors brazed in this manner were evaluated in the same manner as in the examples and conventional examples. The results are shown in Table 1.

As is clear from the results in Table 1, the surface of the capacitor after brazing in the brazing furnace of the present invention is clean, and the brazing condition is also good at the fin part, which is the joint between the fin and the pipe material, and the connector and the pipe material. Some of the connectors, which are the joints, were excellent. Furthermore, the chromate property and paintability were also good, and the corrosion resistance was also good.

On the other hand, the capacitors manufactured by the conventional method have a thick flux residue all over the surface (it adheres unevenly, which is unfavorable for the appearance.Also, the brazing condition was good on the fin part, but some parts of the connector were brazed. In addition, the chromate treatment and painting after brazing were uneven, and as for corrosion resistance, through-pitting corrosion occurred particularly at the bent part 36 of the pipe material 33 in Fig. 3.Furthermore, the capacitor according to the comparative example had Although the appearance etc. are more beautiful than those made by the conventional example, poor joining occurs in some parts, and it is inferior to the waxed bone made by the furnace of the present invention.

Reference Example 1 Brazing was carried out in the same manner as in Example 2 except that an evaporator as shown in FIG. 4 was used as the member to be brazed.

The evaporator was manufactured as follows. Fourth
As shown in the figure, the side plate 38 is made of a plate material in which the core material 3003 is press-formed into a predetermined shape by a conventional method and 4045 (Afi-10% Si) is clad on one side, and the core material 3003 is made of a plate material in which 4045 (Afi-10% Si) is clad on one side. A press plate 40 made of a plate material clad on both sides with Si) and a corrugated fin 39 made of an Afl-1%Mn-1,5%Zn alloy were laminated and assembled. In addition, the piping/connector 37 in FIG. 4 was joined by welding after brazing.

After completion of vapor phase brazing, the appearance and brazing condition of the parts to be brazed were examined and the results are shown in Table 2.

Reference Example 2 Using the apparatus used in Reference Example 1, an evaporator was brazed without using only the evacuation apparatus.

For brazing, the evaporator is placed in the brazing furnace at room temperature, the valve 28a is opened, and the above-mentioned mixed gas is poured into the brazing furnace at room temperature.
It was heated to 00'C and introduced into the furnace. 600±10° where the inside of the brazing furnace is not sufficiently replaced with mixed gas and the temperature is not raised.
C, and after holding for 5 minutes, the valve 28a was closed, and the member to be brazed was taken out of the furnace and cooled to room temperature.

After the evaporator brazed in the above method was taken out of the furnace and cooled to room temperature, the appearance of the surface was observed, and the brazing condition was examined, and the results were as shown in Table 2. When the apparatus shown in FIG. 2 equipped with a vacuum evacuation device is used, the small joints between the press plates are also well bonded to the wax bone.

(Effects of the Invention) As described above, according to the present invention, flux vapor can be stably supplied to the brazing area together with non-oxidizing atmospheric gas, and since the surface of the solder joint is clean, it is possible to perform chromate treatment, etc. Good surface treatment properties in post-treatment and excellent corrosion resistance. Furthermore, compared to the conventional wax-bone method, no flux application process is required, and the manufacturing process for heat exchangers for automobiles, for example, can be shortened, so that manufacturing costs can be reduced.

Furthermore, in the second aspect of the invention, the flux vapor enters between the press plates of the evaporator, and the vapor is uniformly supplied even to the parts near the closed space, making it possible to perform dense brazing.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing an example of the vapor phase brazing apparatus of the present invention, Figure 2 is a schematic diagram showing another example, and Figures 3 (a) and (b) are of a condenser which is a heat exchanger for an air conditioner. A perspective view showing an example and a side view showing an enlarged fin part, FIG. 4(a),
(b) is an assembled diagram and perspective view of the evaporator, No. 5
The figure is a typical brazing process diagram using a conventional fluoride flux, and FIG. 6 is a schematic diagram of a brazing furnace using a conventional fluoride flux. Explanation of symbols 1.19... Gas phase brazing device, 2.20... Brazing furnace, 3.23... Flux steam generator, 4.28
...Gas guide pipe, 5a, 5b...Metal curtain 6
... Inlet, 7... Outlet, 8... Belt conveyor 9.30... Brazing parts, 10.11.31...
Electric heater, 13.27... Container, 15.25...
・Non-oxidizing gas introduction pipe, 17a, 17b... communication hole,
18a, 18b...Exhaust pipe, 12.26...Flux, 14.24...Electric heater, 16.29...
- Branch pipe, 21a, 28a... valve, 32... entrance/exit, route conveyor, 33... pipe material, 34... fin, 35... connector, 36... bent part, 37
...Piping, connector, 38...side plate,
39...Fin, 40...Press plate, 41.
... Brazing furnace, 42 ... Population, 43 ... Exit, 44
a, 44b... Metal curtain, 45... Belt conveyor, 46... Brazing member, 47.48...
Electric heater, 49... Gas supply port, 50... Exhaust pipe, A... Fillet length Fig. 3 (a) ('b) To--H 401-

Claims (2)

[Claims] (1) A brazing device for brazing aluminum or aluminum alloy materials with a brazing material, which generates flux vapor by heating flux with a melting point m_p outside the furnace to a temperature of (m_p-50)°C or higher. In addition to disposing a generating device, a passageway for transporting the flux vapor generated by the device while being supported by a non-oxidizing gas, and a means for guiding and blowing out the transported flux vapor to the joining site of the parts to be brazed in the furnace. A vapor phase brazing device comprising: (2) The vapor phase brazing apparatus according to claim 1, wherein the brazing furnace is sealable and is equipped with a vacuum evacuation device for evacuating the inside of the brazing furnace.