JPH0768374A - Method for joining aluminum material to stainless steel - Google Patents

Abstract

PURPOSE:To suppress formation of an alloy layer in the interface between stainless steel and brazing filler metal. CONSTITUTION:Al-Si-base brazing filler metal 3 is used as brazing filler metal. A brazing filler metal ring 3 is then arranged on the aluminum pipe end face 1b, an end 2a of stainless steel pipe 2 is inserted into the aluminum pipe 1 end 1a and flux 4 is applied on the stainless steel pipe end 2a outside. Continuously, heating is carried out in a short time by using a high-frequency induction heating coil 5 and brazing is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, joining of aluminum tubular bodies of various aluminum heat exchangers with stainless steel inlet / outlet pipes, aluminum tubular parts used as cryogenic pipes, and stainless steel tubular pipes. The present invention relates to a method for joining an aluminum material and a stainless steel material, which is applied to joining parts, joining CT scanner superconducting (MR) parts, and the like.

In the present specification, the term "aluminum" means not only pure aluminum but also aluminum alloy.

[0003]

2. Description of the Related Art For example, an air conditioner that can be used for cooling in the summer and for heating in the winter uses a Freon or the like which is used as a cooling medium in the summer. In the winter, the heat of combustion of an oil burner or a gas burner is used to evaporate the heat, and the latent heat is used to perform heating. In this cooling and heating device, the heating of the refrigerant by the combustion heat of the burner is performed by a heat exchanger, and the heat exchanger shown in FIG. 4 has been used. In the following description, the direction indicated by the arrow X in FIG. 4 is referred to as the front and the opposite side is referred to as the rear, the direction indicated by the arrow Y in the same figure is referred to as the left, and the opposite side is referred to as the right.

In FIG. 4, a heat exchanger (10) is attached to a lateral cylindrical combustion cylinder (11) having open front and rear ends, and is attached to the rear end of the combustion cylinder (11) and uses oil, gas or the like as fuel. The burner (B) and the heat transfer bulkhead (1) made of an aluminum plunging sheet for closing the front end opening of the combustion cylinder (11)
2), a high temperature gas passageway (13) formed inside the heat transfer partition wall (12), and a plurality of coolant passageways (b) which are brazed to the outer surface of the heat transfer partition wall (12) and which extend vertically inwardly. A flat refrigerant flow pipe (14) made of an aluminum extruded shape having a not shown).

The combustion cylinder (11) has a cylindrical portion (11a) and an expanding portion (11b) formed at the front end of the cylindrical portion (11a).
And a combustion chamber (15) inside the cylindrical part (11a).
Has been made. The inner peripheral surface of the cylindrical portion (11a) is covered with a heat insulating material (16). A hot gas passage (13) is provided in the expansion portion (11b). Expanded part (11
An exhaust port (17) for connecting an exhaust pipe is formed at the upper end of b).

[0006] The heat transfer partition wall (12) is formed of a plaging sheet made of a core material and a brazing filler metal material covering both surfaces of the core material. The heat transfer partition wall (12) is provided with a bulging part (19) which bulges slightly inward except for the frame-shaped predetermined width part (18) at the periphery thereof, and the high temperature gas is formed on the inner surface of the bulging part (19). A passage (13) is provided, and a refrigerant flow pipe (14) is brazed to the outer surface.

The high temperature gas passage (13) is provided with two high temperature gas flow restricting members (21) (22) made of aluminum extruded profile, which are vertically arranged at a predetermined interval. The width of the upper hot gas flow restricting member (21) in the left-right direction is larger than the width of the lower hot gas flow restricting member (22) in the left-right direction, and the left and right edges of the upper hot gas flow restricting member (21) are The part projects laterally beyond the lower hot gas flow restricting member (22). And the high temperature gas flow restricting member (22) on the lower side
At a position corresponding to both left and right side wall portions (22a) of the exhaust gas, the exhaust gas is laterally disposed between the upper and lower high temperature gas flow restricting members (21, 22). A gas leakage prevention part (23) is provided to prevent outflow to the. Upper and lower high temperature gas flow restricting members (21) (2
2) is directly brazed to the heat transfer partition wall (12) and is fixed to the heat transfer partition wall (12) through fixing members (24) having a substantially L-shaped cross section extending vertically on both left and right sides. . Further, a gas leakage preventing portion (23) is integrally provided on the fixing member (24).

The cylindrical portion (11) of the combustion cylinder (11)
The front end periphery of a) is the upper and lower high temperature gas flow restricting members (21).
(22) It is brought into contact with the rear surface of the rear wall portion, and is plate-shaped between the rear wall portion of the expanding portion (11b) and the rear wall portions of the upper and lower high temperature gas flow restricting members (21) and (22). Seal (25)
And the flange (1
1c) is a frame-shaped predetermined width portion (18) of the heat transfer partition wall (12)
It is screwed to.

Both upper and lower ends of the refrigerant flow pipe (14) are bent forward so as to be horizontally oriented, and the front end of the forward bent portion (14a) is cylindrical header (26) (2).
7) is connected. The lower header (27) is the inlet side header, and the aluminum connecting pipe (2
A stainless steel refrigerant inlet pipe (29) is connected via 8). The oil of the compressor is always dissolved in the refrigerant, and when the refrigerant is heated and vaporized, this oil gradually accumulates, and its viscosity and low heat conductivity impede the vaporization and circulation of the refrigerant. An oil drain pipe (30) is connected to the right end of the side header (27). The upper header (26) is the outlet header,
A stainless steel refrigerant outlet pipe (32) is connected to the left end portion thereof through an aluminum connecting pipe (31). In this type of heat exchanger (10), a copper pipe is usually used as a refrigerant supply pipe for supplying a refrigerant to the inlet side header (27) and a refrigerant discharge pipe for discharging a refrigerant from the outlet side header (26). Used as a refrigerant inlet pipe (29)
And if the refrigerant outlet pipe (32) is made of stainless steel,
Welding with copper pipes is easy. Both headers (2
6) Long holes (26a) (27a) extending in the axial direction are formed in the peripheral wall of (27), and the tip of the bent portion (14a) of the refrigerant flow pipe (14) is formed in the long hole (26).
a) (27a), inserted into the headers (26) and (27), and brazed to the peripheral walls of the headers (26) and (27).

Although not shown, both headers (26) (2
In 7), the plunging sheet in which both sides of the core material are covered with the brazing filler metal is provided with slanted portions which are superposed on each other, and the plunging sheet has a cylindrical shape so that the slanted portions overlap each other. Is formed into a header material, and the inclined portions of the header material are brazed to each other. Brazing of the inclined portions is performed at the same time as brazing of the headers (26) (27), the refrigerant flow pipe (14) and other parts.

The heat exchanger as described above is conventionally manufactured as follows. That is, the heat transfer partition (1
2), upper and lower high temperature gas flow restricting members (21) (22),
The refrigerant flow pipe (14), the oil drain pipe (30), and the above header material formed by forming a plaging sheet into a cylindrical shape are combined and temporarily fixed with an appropriate jig, and then brazed together in a furnace. Also, aluminum connecting pipe (28)
And a stainless steel refrigerant inlet pipe (29), and an aluminum connecting pipe (31) and a stainless steel refrigerant outlet pipe (3
2) and are joined together by the flash pad welding method or the explosive pressure welding method. After that, the refrigerant inlet pipe (2
9) The other end of the connecting pipe (28) joined to the inlet side header (27), and the other end of the connecting pipe (31) joined to the refrigerant outlet pipe (32) to the outlet side header (26). Are welded by the argon arc welding method. Finally, the combustion cylinder (11) is fixed to the heat transfer partition (12). Thus, the heat exchanger (10) was manufactured.

However, in order to manufacture the heat exchanger (10) by the above-mentioned method, four steps are required, so that there is a problem that the number of steps is increased and the work is troublesome.

By the way, the applicant of the present invention first found that Al--Si
A method of brazing an aluminum material and a stainless steel material by heating to a predetermined temperature in a non-oxidizing atmosphere using a brazing filler metal and a fluoride-containing flux containing tin fluoride has been proposed. 4-40112).

When this method is applied to the production of the heat exchanger (10) shown in FIG. 4, the heat transfer partition wall (12), the upper and lower high temperature gas flow restricting members (21) and (22), and the refrigerant flow pipe (1).
4), the oil drain pipe (30), and the above header material formed by forming a plaging sheet into a cylindrical shape are temporarily fixed with an appropriate jig, and the aluminum connecting pipe (28)
(31), the stainless steel refrigerant inlet pipe (29), and the stainless steel refrigerant outlet pipe (32) are temporarily fixed with an appropriate jig, and then a fluoride-based flux containing tin fluoride is used, All parts can be brazed together by heating to a predetermined temperature in a non-oxidizing atmosphere. Therefore, when compared with the conventional method, the aluminum connecting pipe (28) and the stainless steel refrigerant inlet pipe (29), and the aluminum connecting pipe (31) and the stainless steel refrigerant outlet pipe (32) are respectively provided. Process of joining by flash bud welding method or explosive pressure welding method,
And a connecting pipe (2) joined to the refrigerant inlet pipe (29)
The other end of 8) is welded to the inlet header (27) and the other end of the connecting pipe (31) joined to the refrigerant outlet pipe (32) is welded to the outlet header (26) by an argon arc welding method. This simplifies the work by eliminating the process of performing.

However, since this method requires heating in a non-oxidizing atmosphere, heating must be performed in a furnace whose atmosphere is adjusted, and it is inevitable that the heating time is long. As a result, the aluminum connecting pipes (28) (31) and the stainless steel refrigerant inlet pipe (2
9) and the alloy layer formed at the interface between the stainless steel material and the Al—Si brazing material at the joint with the refrigerant outlet pipe (32) has a thickness of about 20 μm. Therefore, there is a problem that cracks are likely to occur due to vibration or the like. Further, in order to reduce the formation of the alloy layer, it is conceivable to form a metal plating layer of Ag, Ni or the like on the stainless steel material in advance, but the number of steps increases and the cost increases.

An object of the present invention is to provide a method for joining an aluminum material and a stainless steel material, which solves the above problems.

[0017]

According to the method for joining an aluminum material and a stainless steel material of the present invention, the aluminum material and the stainless steel material are joined together by using Al as a brazing material.
Brazing is performed by high-frequency induction heating using a Si-based brazing material.

In the above, as the Al-Si brazing material, one having a Si content of about 6.8 to 13 wt% is used. The brazing material may be clad in advance with an aluminum material.

The conditions for high frequency induction heating are usually a high frequency output of 20 to 40 kHz and a heating time of 10 to 20 seconds.

In the method of the present invention, it is preferable to use a fluoride-based flux or a fluoride-based flux added with tin fluoride as the flux.

The fluoride-based flux is not particularly limited, but examples thereof include fluoroaluminum complex salts such as K ₃ AlF ₆ and KAlF ₄ , a mixture of KAlF ₄ and KF, a mixture of AlF ₃ and KF, and the like. Can be mentioned. Of these, a mixture of KAlF ₄ and KF is preferable from the viewpoint of non-corrosiveness of flux residue and easy availability.

Further, it is more preferable to use a fluoride-based flux to which tin fluoride is added, because the addition of tin fluoride can form a uniform fillet at the joint and obtain a good and stable joint. . The addition amount of tin fluoride is generally 0.05 to 15 wt%, preferably 0.3 to 5.0 wt%.

The fluoride-based flux or the fluoride-based flux to which tin fluoride is added is suspended in a liquid such as water or alcohol, and this suspension is used for bonding one or both of aluminum material and stainless steel material. Applied to the area.

In the method of the present invention, the stainless steel material is preferably preliminarily plated with at least one metal selected from the group consisting of Ag, Ni and Ti. By applying metal plating, formation of the alloy layer can be further suppressed.

Next, a method of manufacturing the heat exchanger (10) shown in FIG. 4 using the method of the present invention will be described. First, the header formed by forming the heat transfer partition wall (12), the upper and lower high temperature gas flow restricting members (21) and (22), the refrigerant flow pipe (14), the oil drain pipe (30), and the plaging sheet into a cylindrical shape. Material and aluminum connecting pipe (28)
Temporarily fix (31) with an appropriate jig and heat it in a furnace to braze them all together. Then, the stainless steel refrigerant inlet pipe (29) and the stainless steel outlet pipe (32) are fitted to the tips of the connecting pipes (28) and (31). The Al-Si brazing material is used as a brazing material, and the flux is a fluoride flux or a fluoride flux to which tin fluoride is added, and the coupling pipes (28) and (31) are subjected to high frequency induction heating. A stainless steel refrigerant inlet pipe (29) and the same outlet pipe (32) are brazed to the tip. Thus, the heat exchanger (10) is manufactured.
According to this manufacturing method, the aluminum connecting pipe (28)
And a stainless steel refrigerant inlet pipe (29), and an aluminum connecting pipe (31) and a stainless steel refrigerant outlet pipe (3
And (2) are respectively joined by a flash pad welding method or an explosion pressure welding method, and a refrigerant inlet pipe (2
9) The other end of the connecting pipe (28) joined to the inlet side header (27), and the other end of the connecting pipe (31) joined to the refrigerant outlet pipe (32) to the outlet side header (26). In addition, the work is simplified because the welding process by the argon arc welding method is not required. Moreover, the connecting pipe (28) (31)
Since the brazing between the stainless steel refrigerant inlet pipe (29) and the stainless steel refrigerant inlet pipe (32) is performed by high frequency induction heating, the heating time is short. Therefore, formation of an alloy layer at the interface between the stainless steel material and the brazing material is suppressed.

Further, in the method of the present invention, the connecting pipe is omitted from the heat exchanger (10) shown in FIG. 4, and the stainless steel refrigerant inlet pipe (29) is provided on the inlet side header (27), and the stainless steel refrigerant is provided. It can also be applied to manufacture a heat exchanger in which the outlet pipe (32) is directly joined to the outlet header (26). In this case, no brazing material should be present on the outer peripheral surfaces of both headers (26) (27). Therefore, as the both headers (26) and (27), it is preferable to use those made of ordinary aluminum pipes, for example. In this case, the heat transfer partition wall (12), the upper and lower high temperature gas flow restricting members (21) and (22), the refrigerant flow pipe (14), the oil drain pipe (30), and the aluminum pipe for header are appropriately treated. Temporarily fix with a tool and heat them in a furnace to braze them together. Then both headers (26)
The stainless steel refrigerant inlet pipe (29) and the outlet pipe (32) are fitted to the tip of (27). And Al-
Using a Si-based brazing filler metal as a brazing filler metal, and using a fluoride-based flux or a fluoride-based flux with tin fluoride added as the flux, stainless steel is attached to the tips of the headers (26) (27) by high frequency induction heating. The refrigerant inlet pipe (29) and the outlet pipe (32) are brazed. Thus, the heat exchanger (10) is manufactured. In the above method, the refrigerant flow pipe (14) and both headers (26)
The brazing with (27) is performed by the placement brazing method. According to this manufacturing method, since the connecting pipes (28) and (31) are not required, the number of parts is reduced and the cost is reduced.
Moreover, the step of joining the aluminum connecting pipes (28) and (31) with the stainless steel refrigerant inlet pipe (29) and the stainless steel refrigerant outlet pipe (32) by flash bud welding or explosion pressure welding, respectively, and The other end of the connecting pipe (28) joined to the refrigerant inlet pipe (29) is the inlet side header (27), and the other end of the connecting pipe (31) joined to the refrigerant outlet pipe (32) is the outlet side. Header (26)
In addition, the work is simplified because the welding process by the argon arc welding method is not required. Further, the aluminum headers (26) and (27) are brazed to the stainless steel refrigerant inlet pipe (29) and the stainless steel refrigerant outlet pipe (32) by high frequency induction heating, so that the heating time is short. Therefore, formation of an alloy layer at the interface between the stainless steel material and the brazing material is suppressed.

[0027]

According to the method for joining an aluminum material and a stainless steel material of the present invention, an Al-Si type brazing material is used as the brazing material, and a fluoride type flux or a fluoride type flux to which tin fluoride is added is used as the flux. make use of,
Since brazing is performed by high frequency induction heating, heating can be performed in a short time. Therefore, formation of an alloy layer at the interface between the stainless steel material and the brazing material is suppressed.

[0028]

[Examples] The joining method of the present invention is described below in accordance with JIS A30.
An embodiment applied to the connection of a pipe made of 03 and a pipe made of JIS SUS304 will be specifically described with reference to the drawings.

[Embodiment 1] In FIG. 1, the inner diameter of the end portion (1a) of the aluminum pipe (1) is 13.4 mm, and the pipe wall thickness is 1.2 mm. On the other hand, the outer diameter of the stainless steel pipe (2) is 12.7 mm and the pipe wall thickness is 0.5 mm.

FIG. 1A shows both pipes (1) before heating.
(2) is a vertical sectional view showing the arrangement of the brazing material ring (3), and FIG. 1 (B) shows both pipes (1) after brazing by heating.
It is a vertical sectional view showing a state of joining of (2).

In this embodiment, an Al-Si type brazing material ring (JIS B) is attached to the end face (1b) of the aluminum pipe.
A4045, Si content 10 wt%) (3) is placed, and the end (11a) of the stainless steel pipe (2) is inserted into the end (1a) of the aluminum pipe, and the fluoride flux (4) is added to the stainless steel. Steel pipe end (11
a) Applied on the outer surface. This fluoride flux (4)
Is based on a mixture of KAlF ₄ (85 wt%) and KF (15 wt%), to which SnF ₂ of 1 wt% was added and suspended in ethyl alcohol to a concentration of 40 wt% (Fig. 1). (See (A)).

Subsequently, the brazing material (3) is heated by using a high frequency induction heating coil (5) (length in the axial direction is 15 mm).
Was melted and the aluminum pipe (1) and the stainless steel pipe (2) were joined (see FIG. 1 (B)). The heating conditions at this time are: high frequency output 30 kHz, power source 20 kW,
The time was 17 seconds.

In this way, the brazability of the connected aluminum pipe (1) and stainless steel pipe (2) was very good. Furthermore, the cross section of the bonded portion was observed with an optical microscope to obtain an optical microscope photograph. FIG. 2 is a copy of an optical microscope photograph (× 200 times), and FIG. 3 is a copy of an optical microscope photograph (× 800 times). From FIG. 3, the thickness of the alloy layer (6) formed at the interface between the steres steel pipe (2) and the solidified brazing material (3a) is about 2 to 3 μm.
And became very thin. This thickness is 5 μm
If it is below, there is no problem in practical use.

According to the above method, since heating is performed in a short time by high frequency induction, formation of the alloy layer (6) at the interface between the stainless steel pipe (2) and the brazing material (3a) is significantly suppressed. . As a result, the joining of these pipes (1) and (2) was very good.

[Example 2] Fluoride flux (4)
The aluminum pipe (1) and the stainless steel pipe (2) were connected in the same manner as in Example 1 except that the concentration of the ethyl alcohol suspension in (2) was changed to 20 wt%.

According to this method, the brazing property was good although it was slightly inferior to that of Example 1. In addition, when the cross section of the joint portion was observed with an optical microscope, Example 1
As in the case of No. 3, the thickness of the alloy layer (6) formed at the interface between the stainless steel pipe (2) and the solidified brazing material (3a) was very thin, about 2 to 3 μm.

[0037]

According to the joining method of the present invention, as described above, the formation of the alloy layer at the interface between the stainless steel material and the brazing material is suppressed, so that the joining with excellent strength against vibration and the like can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a joining method of the present invention. Figure 1 (A)
FIG. 3 is a vertical sectional view showing the arrangement of both pipes (1) and (2) and a brazing material ring (3) before heating. Figure 1 (B)
FIG. 3 is a vertical cross-sectional view showing a state of joining both pipes (1) and (2) after brazing by heating.

FIG. 2 is an optical micrograph (× 200) of a cross section of a joint portion.
Times).

FIG. 3 is an optical micrograph (× 800) of a cross section of a joint portion.
Times).

FIG. 4 is a partially cutaway perspective view of a heat exchanger used in an air conditioner.

[Explanation of symbols]

 (1) ... Aluminum pipe (1a) ... Aluminum pipe end (1b) ... Aluminum pipe end face (2) ... Stainless steel pipe (2a) ... Stainless steel pipe end (3) ... Brazing material ring (4) … Flux (5)… High frequency induction heating coil

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[Procedure amendment]

[Submission date] December 14, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The upper and lower ends of the refrigerant flow pipe (14) are respectively bent forward so as to be horizontally oriented, and the tip of the forward bent portion (14a) is connected to the cylindrical headers (26) and (27). ing. Lower header (27) is an inlet side header through aluminum connecting tube (28) refrigerant inlet pipe at its left end (29)
Are connected. The oil of the compressor is always dissolved in the refrigerant, and when the refrigerant is heated and vaporized, this oil gradually accumulates, and its viscosity and low heat conductivity impede the vaporization and circulation of the refrigerant. The oil drain pipe (30) is connected to the right end of the side header (27). The upper header (26) and an outlet side header through aluminum connecting tube (31) refrigerant outlet pipe at its left end (3
2) is connected. Long holes (26a) and (27a) extending in the axial direction are formed on the peripheral walls of both headers (26) and (27), and the tip of the bent portion (14a) of the refrigerant flow pipe (14) is formed in this long hole. (2
6a) (27a) and inserted into the header (26) (27)
(26) It is brazed to the peripheral wall of (27). In addition, this kind of heat exchange
In the exchanger (10), the refrigerant is usually supplied to the inlet header (27).
Refrigerant supply pipe to supply, and refrigerant from outlet header (26)
Copper pipes are used as the refrigerant discharge pipes for
Therefore, it is easy to weld these copper pipes.
To enable, the refrigerant inlet pipe (29) and the refrigerant outlet pipe (3
2) was made of copper.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The heat exchanger as described above is conventionally manufactured as follows. That is, the heat transfer partition (12), the upper and lower high temperature gas flow restricting members (21) (22), the refrigerant flow pipe (14),
The oil drain pipe (30) and the above header material formed by forming a brazing sheet into a cylindrical shape are combined, temporarily fixed with an appropriate jig, and brazed together in a furnace. Further, an aluminum connecting pipe (28) and a copper refrigerant inlet pipe (29), and an aluminum connecting pipe (31) and a copper refrigerant outlet pipe (32),
Each of them is joined by flash bud welding method or explosive pressure welding method. Then, connect the other end of the connecting pipe (28) joined to the refrigerant inlet pipe (29) to the inlet header (27)
Connect the other end of the connecting pipe (31) joined to (32) to the outlet side header (2
6) are welded by the argon arc welding method.
Finally, the combustion cylinder (11) is fixed to the heat transfer partition (12). Thus, the heat exchanger (10) was manufactured.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

However, in order to manufacture the heat exchanger (10) by the above-mentioned method, four steps are required.
There was a problem that the number of man-hours increased and the work was troublesome. Moreover, the inlet side header (27) and the outlet side header (26)
Is made of aluminum and has a refrigerant inlet tube (29) and a refrigerant outlet.
Since the mouth tube (32) is made of copper,
Corrosion may occur at the joint, so anticorrosion treatment
There is a problem that it has to be done and the work is troublesome.
It was.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

If this method is used,
For brazing stainless steel materials to aluminum materials
It can be done at the same time as brazing. Therefore, the heat exchange
In the container (10 ), the refrigerant inlet pipe (29) and the refrigerant outlet pipe (32)
It is possible to use stainless steel as
It was The refrigerant inlet pipe (29) and the refrigerant outlet pipe (32) are
Refrigerant inlet pipe (29) and refrigerant outlet, even if made of stainless steel
Welding the pipe (32) to the copper coolant supply pipe and coolant discharge pipe
Easy to do. And Japanese Patent Publication No. 4-4011
The method described in Japanese Patent No.
A heat exchanger (1 with a medium inlet pipe (29) and a refrigerant outlet pipe (32)
When applied to the production of (0), the heat transfer partition wall (12), the upper and lower high temperature gas flow restricting members (21) (22), the refrigerant flow pipe (14), the oil drain pipe (30), and the brazing sheet are cylindrical. While temporarily fixing the header material formed by molding to a suitable jig, the aluminum connecting pipe (28) (31), stainless steel refrigerant inlet pipe (29), and stainless steel refrigerant outlet pipe (32) It was temporarily fixed in a suitable jig, followed by using the fluoride-based fluxes containing stannous fluoride, by heating to a predetermined temperature in a non-oxidizing atmosphere, brazed collectively all parts be able to. Therefore, the coolant inlet pipe made of copper
(29) and heat exchanger (10) with refrigerant outlet pipe (32 )
Aluminum connecting pipe when compared to the conventional method
(28) and the copper refrigerant inlet pipe (29), and the aluminum connecting pipe (31) and the copper refrigerant outlet pipe (32), respectively, the step of joining by flash bud welding or explosion pressure welding method, and the refrigerant inlet pipe ( 29) the other end of the connecting pipe (28) joined to the inlet side header (27), the other end of the connecting pipe (31) joined to the refrigerant outlet pipe (32) the outlet side header (26). In addition, the work is simplified because the welding process by the argon arc welding method is not required. Moreover, the inlet header (27) and the outlet
Side header (26) with refrigerant inlet pipe (29) and refrigerant outlet pipe (32)
There is no risk of corrosion occurring at the joints with.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Next, using the method of the present invention, stainless steel is used.
Figure 4 with steel refrigerant inlet pipe (29) and refrigerant outlet pipe (32)
A method for manufacturing the heat exchanger (10) shown in will be described.
First, the heat transfer partition (12) and the upper and lower hot gas flow restricting members (21)
(22), the refrigerant flow pipe (14), the oil drain pipe (30), the header material formed by molding the brazing sheet into a cylindrical shape, and the aluminum connecting pipes (28) (31) are temporarily fixed with an appropriate jig. These are brazed together by stopping and heating in a furnace. Next, the stainless steel refrigerant inlet pipe (29) and the stainless steel outlet pipe (32) are fitted to the ends of the connecting pipes (28) (31). Then, using Al-Si brazing filler metal as a brazing filler metal, and using a fluoride type flux or a fluoride type flux to which tin fluoride has been added as a flux, the coupling pipe (28) (31) of high-frequency induction heating is used. A stainless steel refrigerant inlet pipe (29) and the same outlet pipe (32) are brazed to the tip.
Thus, the heat exchanger (10) is manufactured. According to this manufacturing method, the consolidated tube (28) (31) of stainless steel refrigerant inlet pipe (2
Brazing with 9) and the outlet pipe (32) is performed by high frequency induction heating, so that the heating time is short. Therefore, formation of an alloy layer at the interface between the stainless steel material and the brazing material is suppressed.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

The method of the present invention is also applicable to the cold
A connecting pipe is omitted from the heat exchanger (10) shown in FIG. 4 having the medium inlet pipe (29) and the refrigerant outlet pipe (32), and the stainless steel refrigerant inlet pipe (29) is connected to the inlet side header (27). It can also be applied to manufacture a heat exchanger in which the stainless steel refrigerant outlet pipe (32) is directly joined to the outlet side header (26). In this case, no brazing material should be present on the outer peripheral surfaces of both headers (26) (27). Therefore, as the both headers (26) and (27), it is preferable to use, for example, those made of ordinary aluminum pipes. In this case, the heat transfer partition wall (12), the upper and lower high temperature gas flow restricting members (21) and (22), the refrigerant flow pipe (14), the oil drain pipe (30), and the aluminum pipe for header are appropriately treated. Temporarily fix with a tool and heat them in a furnace to braze them together. Then, both headers (26) (2
The stainless steel refrigerant inlet pipe (29) and outlet pipe (32) are fitted to the tip of 7). Then, the Al-Si brazing filler metal is used as the brazing filler metal, and the flux is a fluoride type flux or a fluoride type flux to which tin fluoride is added, and the header (26) (27) by high frequency induction heating.
Stainless steel refrigerant inlet pipe (29) and outlet pipe at the end of the
Braze (32). Thus, the heat exchanger (10) is manufactured. In the above method, the refrigerant flow pipe (14) and the headers (26) and (27) are brazed by the placement brazing method. According to this manufacturing method, since the connecting tube (28) does not require (31), a that cheaper cost parts becomes small. In is al <br/>, brazing of aluminum headers (26) (27) of stainless steel refrigerant inlet pipe (29) and the outlet pipe (32) is so carried out by high-frequency induction heating, the heating time But in a short time. Therefore, formation of an alloy layer at the interface between the stainless steel material and the brazing material is suppressed.

Claims (3)

[Claims] 1. A method of joining an aluminum material and a stainless steel material, characterized in that, when joining an aluminum material and a stainless steel material, brazing is performed by high frequency induction heating using an Al—Si based brazing material as a brazing material. . 2. The method according to claim 1, wherein a fluoride-based flux or a fluoride-based flux added with tin fluoride is used as the flux. 3. The method according to claim 1, wherein the stainless steel material is previously plated with at least one metal selected from the group consisting of Ag, Ni and Ti.