JPH06134568A - Heat exchanger made of aluminum - Google Patents

Abstract

PURPOSE:To simplify soldering process for consisting members and provide a heat exchanger made of aluminum excellent in solderability, appearance, quality and surface treatment suitability. CONSTITUTION:In the aluminum made heat exchanger provided with a tube 11, a fin 12, headers 13 and 14 and a bracket 16, at least, one of the fin 12, the headers 13 and 14 and the bracket 16 is formed by cladding the liner material 52, a soldering layer, on at least, one face of a core material 51. Al, Si and a fluoride flux are contained in the liner material 52, the content of Si is 5-15wt.% in the total content of elements except the fluoride flux, the elements and the flux are blended in a ratio in wt.% 98:2-88:12 and the density is equal to or more than 90% of the theoretical value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum heat exchanger in which tubes, fins, headers and brackets are used as constituent members, and these members are integrated by brazing.

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

[0003]

2. Description of the Related Art Generally, automobile capacitors and radiators.
The aluminum heat exchanger used for the heater and the like is manufactured by brazing and joining members such as tubes, fins, headers and brackets made of an aluminum material.

In the conventional aluminum heat exchanger manufacturing process, for each of these members, a brazing sheet is first produced by clad an Al alloy as a core material with a liner material as a brazing material layer, and then this brazing sheet is manufactured. It is manufactured by forming each member into a predetermined shape by pressing or the like. Then, after supplying a fluoride-based flux to these members by coating or the like, brazing is performed in a nitrogen atmosphere.

[0005]

However, when the aluminum heat exchanger is joined by the brazing method as described above, there are many joints and it is difficult to automate the flux application. However, this flux application is a very troublesome work. Further, for example, there is a portion such as the inside of the header where the flux application cannot be performed after the heat exchanger is assembled, and the work procedure from the flux application to the brazing must be complicated.

Further, since the flux itself is supplied by coating, the coating amount is likely to vary, a brazing defect may occur in a portion where the coating amount is small, or a flux may be applied in order to apply sufficient flux to the joint portion. When used in a large amount, there are various problems that the appearance quality and surface treatability of the brazed product are deteriorated by the residual flux after brazing.

In order to solve these problems, the present invention is excellent in brazing property, appearance quality and surface treatment property, and can simplify the brazing process including the supply of flux, which is made of aluminum. Is to provide.

[0008]

In order to achieve the above-mentioned object, the aluminum heat exchanger of the present invention has a plurality of heat exchange tubes (11) arranged in parallel and adjacent tubes (11) (11). ) Between the fins (1
2) and a pair of hollow headers (13, 14) in which both ends of each of the tubes (11) are communicatively connected are used as the basic configuration of the heat exchanger body (15), and the heat exchanger body (1
5) An aluminum heat exchanger comprising a mounting bracket (16) of 5), and these respective members (11) (12) (13, 14) (16) being integrated by brazing. , At least one of the headers (13, 14) and the bracket (16) is formed by cladding a liner material (52) as a brazing material layer on at least one surface of a core material (51) made of aluminum. In addition, the liner material (52) is made of Al, S
i content is 5 with respect to the total content of the elements including i and the fluoride-based flux and excluding the fluoride-based flux.
˜15 wt%, and the weight ratio of the total of elements excluding the flux and the fluoride-based flux is 98: 2 to 88: 1.
It is characterized in that it is formed by a material having a ratio of 2 and having a density of 90% or more of the theoretical value.

The liner material (52) contains mainly Al, Si, and a fluoride-based flux, and further Z
At least one of n, In, and Sn is included, and the Si content is 5 to 15 wt% and the Zn content is 0.05 with respect to the total content of elements excluding the fluoride flux.
˜3 wt%, In content is 0.01 to 0.1 wt%, Sn content is 0.01 to 0.2 wt%, and the total of elements excluding flux and the fluoride-based flux is 9 by weight ratio.
It is also preferable that the material is blended in a ratio of 8: 2 to 88:12 and has a density of 90% or more of the theoretical value.

The aluminum heat exchanger (10) shown in FIGS. 1 to 3 as an example of the present invention is
A plurality of flat tubes (11) arranged horizontally and vertically, and these adjacent tubes (11)
A pair of left and right hollow headers (13) connected to both ends of each of the tubes (11) and fins (12) interposed between (11) and communicating with these tubes (11)
The heat exchanger body (15) is constructed based on (14),
Further, brackets (16) for engaging and supporting the heat exchanger body (15) above and below the headers (13) and (14) and attaching the heat exchanger body (15) to an external device are provided. ing. Further, in FIG.
7) shows a heat exchange medium inlet pipe, similarly (18) is a heat exchange medium outlet pipe, (19) is a partition plate that divides the headers (13) and (14) into upper and lower chambers, and (20) is a header ( 1
3) Headers (13) (1
A lid for closing 4) and a side plate (21) are shown.

As shown in FIGS. 2 and 3, in such an aluminum heat exchanger (10), both ends of the tube (11) have left and right headers (13).
The tubes (11) and the headers (13) and (14) are inserted into the connection holes (31) provided in (14) so that the tubes (11) and the headers (13) and (14) communicate with each other, and the fins (12) are adjacent to each other in the upper and lower tubes. It is arranged so as to contact (11).
Further, the bracket (16) is formed by bending one piece of aluminum plate material, and the middle portion in the longitudinal direction thereof is bent so as to fit the outer peripheral surfaces of the headers (13) and (14), and the adjoining portion ( 32) is formed, and one end portion is extended from the adjacent portion (42) and bent into an L shape, and the central portion (33) is cut so that the tube (11) is sandwiched and locked. The other end portion of the locking portion (34) is extended from the creeping portion (32) so that the heat exchanger body (1
Mounting parts (35) for mounting the device (5) by engaging with external equipment are respectively formed. Also, the header (13)
Locking protrusions (3
6) is fitted into a locking hole (37) formed in the adjacent portion (32) of the bracket (16), and the header (13) (1)
4) and the bracket (16) are easily engaged. Further, reference numeral (38) in FIG. 3 denotes a bolt insertion hole for attaching to an external device.

In the illustrated embodiment, the aluminum heat exchanger (1
The fins (12), the headers (13) (14) and the brackets (16) of 0) are all made of an Al brazing sheet in which the surface of the core material is clad with the liner material having the above-mentioned predetermined composition. Mutual members are firmly brazed through the material. The fin (1
2), headers (13) (14) and brackets (1
The shape of 6) is not limited to that shown in the figure. Further, it is not necessary to form the headers (13), (14) and the bracket (16) on the fins (12) all having a liner material, and it suffices that at least one of them has a liner material. Further, the Al brazing sheet can be brazed if a liner material is provided on at least one side of the core material, but as shown in FIG. 4, the liner material (52) is provided on both sides of the core material (51). An Al brazing sheet (53) clad with () may be used.

Each member (12) (13, 14) (1)
In the liner material (52) of 6), Al and Si are
It functions as a brazing material for joining aluminum, but if the Si content is less than 5 wt% or 15 wt% with respect to the total content of elements excluding fluoride flux.
If it exceeds, the liquidus temperature becomes high and brazing becomes difficult. Therefore, the Si content must be specified in the range of 5 to 15 wt% with respect to the total value of the elements excluding the flux. A particularly preferable Si content range is 8 to 12 wt%. To further improve the corrosion resistance of the brazing material, Z
You may add one or more types of metal components among n, In, and Sn. These additive metals have a Zn content of 0.05 or less with respect to the total content of elements excluding the fluoride-based flux.
Preferably, the In content is 0.01 to 0.1 wt% and the Sn content is 0.01 to 0.2 wt%. The reason for limiting the content to these ranges is that if it is less than the lower limit of each range, the effect of improving the corrosion resistance of the brazing material is poor, and if it is added in excess of the upper limit, the corrosion resistance is not significantly improved.

The type of the fluoride-based flux is not particularly limited, and may be, for example, 45.8% KF-.
A substantially complexed complex mixture containing a eutectic composition of 54.2% AlF ₃ or a composition range close thereto, KAl
Complexes of F ₄ , K ₂ AlF ₅ , and K ₃ AlF ₆ can be used.

In the composition of the liner material (52) as described above, the total weight of the elements excluding the fluoride-based flux and the fluoride-based flux is 98: 2 to 88:12.
Must be specified in the range. When the fluoride-based flux is less than 98: 2, a sufficient flux effect is not exhibited and brazing becomes difficult. On the other hand, when the fluoride-based flux increases beyond 88:12, the core material (5
The liner material (52) is used when it is clad to 1) or when each member (12) (13, 14) (16) is molded by press working from the Al brazing sheet (53) clad with the liner material (52). This is because it becomes difficult to solidify by cracking or mixing the brazing material component and the flux component, and it becomes difficult to manufacture the liner material (52) itself. The total weight of the elements excluding the fluoride-based flux and the fluoride-based flux is 95: 5 to 9 by weight ratio.
It is more preferably 0:10.

The liner material (52) is generally A
1 powder, Si powder, and flux powder, and Zn powder, In powder, and Sn powder are added to them, mixed, and pressed and solidified by hot pressing or the like. Normally, the density of the liner material (52) is
Although it is smaller than the theoretical value calculated from each of Si, Zn, In, Sn, and the flux simple substance, in the present invention, it must be 90% or more with respect to the theoretical value.
When the density of the liner material (52) is less than 90%, although the material powder is solidified, there is a risk that the pores are connected to the inside to make the material brittle, and subsequent secondary processing or core material (51 ) Is difficult to perform, and the function as the liner material (52) is actually inferior. Particularly preferably, the density of the liner material (52) is the theoretical value of 9
It is better to be 5% or more. Further, in order to densify the brazing filler metal structure, it is preferable to finely pulverize each material powder,
It is preferable that the Al powder has an average particle size of 44 μm or less, the Si powder has an average particle size of 5 μm or less, and the flux powder has an average particle size of 15 μm or less. It should be noted that Al, Si, etc. do not necessarily have to be used alone as a starting material for the liner material (52), and alloy powder such as Al-Si alloy may be used, or these may be used in combination. .

The composition of the core material (51) is not particularly limited, and materials used in conventional aluminum heat exchangers may be used, for example, A3003, 300.
A 3000 series alloy such as 5 or a 6000 series alloy such as A6951 may be used. Further, the Al brazing sheet (53) can be manufactured by pressing the plate-shaped core material (51) and the plate-shaped liner material (52) obtained above in a hot state, and if necessary, further hot rolling. It may be cold-rolled to a required thickness.

[0018]

The fins of the aluminum heat exchanger of the present invention (1
2), headers (13, 14) and brackets (1)
At least one of 6) has a core material (51) clad with a liner material (52) as a brazing material layer, and moreover contains a fluoride-based flux in the liner material (52). Member (12) (13, 14)
When assembling and brazing (16), the brazing material and the fluoride-based flux are simultaneously supplied to the joint portion as the liner material (52) of each member is melted. as a result,
The oxide film on the surfaces of the joints is removed, the brazing filler metal wets and spreads, and good and strong brazing joining is achieved at each joint, as in the case where flux is separately applied. Therefore, it is no longer necessary to separately apply the flux.
Moreover, no matter how the number of joints increases as the size of the aluminum heat exchanger increases, the labor of assembling each member increases, and the labor of brazing itself does not increase.

Furthermore, since a proper and constant amount of flux is supplied to each joint, residual flux after brazing due to excessive supply of flux does not occur.

[0020]

EXAMPLES Next, specific examples of the aluminum heat exchanger of the present invention will be described with reference to the drawings.

First, in order to manufacture a header, a bracket and a fin that constitute an aluminum heat exchanger,
Two kinds of Al brazing sheets (53) in which a liner material (52) was clad on both surfaces of a core material (51) as shown in FIG. 4 were produced.

As a starting material for the liner material (52), Al powder having an average particle size of 44 μm and S having an average particle size of 5 μm are used.
i powder, Zn powder with an average particle size of 44 μm, average particle size of 40 μ
m In powder, Sn powder having an average particle size of 40 μm, and eutectic powder of 45.8% KF-54.2% AlF _{3 having} an average particle size of 15 μm were used. First, these material powders were mixed uniformly at room temperature by changing the mixing ratio so as to have the respective ratios shown in Table 1, and each material was mixed with the desired composition ratio of the liner material (52). A mixed powder that was uniformly mixed was prepared. Next, the mixed powder is treated with an outer diameter of 3 inches and a length of 200.
mm cylindrical cylindrical container made of JIS A1100 alloy,
This container was placed in a furnace at 500 ° C., and the inside of the furnace was evacuated to a vacuum of 1 mmHg or less to degas the filled mixed powder. Further, when it was hot-press molded at a maximum pressure of 400 tons using a hot press at 480 ° C., the molded body was pressed and integrated with the container to have a height of 110 mm. Then, after removing the container press-bonded to the outside of this molded body by cutting, a hot extruder is used to obtain a thickness of 2 mm and a width of 50 at 500 ° C.
It was extruded to mm to obtain a flat liner material.

Next, on both sides of the core material made of JISA3003 alloy, thickness 15 mm x width 50 mm x length 200 mm,
The flat liner material is pressure-welded at a temperature of 500 ° C.,
The pressure-welded material was hot-rolled to a thickness of 3 mm and cold-rolled to a thickness of 1.6 mm. Next, this pressure-rolled material was annealed at 350 ° C. for 2 hours to obtain an O material of Al brazing sheet I in which a core material (51) was clad with a liner material (52) having a thickness of about 170 μm. The hot rolled material having a thickness of 3 mm obtained in the process of manufacturing the Al brazing sheet I was cold rolled to 0.2 mm, annealed at 350 ° C. for 2 hours, and further rolled to 0.14 mm to obtain a core material. (51)
As a result, an H14 material of Al brazing sheet II in which a liner material (52) having a thickness of about 15 μm was clad on both surfaces was obtained.

Further, the Al brazing sheet I is formed into a cylindrical shape to obtain hollow headers (13) and (14) having a shape as shown in FIG. 2, and a bracket (16) is obtained by pressing. It was Further, the Al brazing sheet II was roll-processed to obtain a fin (12) having a shape as shown in FIG. Manufacturing process of these brazing sheets I and II and members (12) (13)
(14) In the process of processing (16), the liner material (52) is visually inspected for cracks, and all the brazing sheets and members can be favorably manufactured or processed. The density of (52) was determined and compared with the theoretical density calculated based on each starting material. The results are shown in Table 1.

[0025]

[Table 1] Then, the well processed No. 1, 3-6, 8, 9,
12-18 headers (13) (14), brackets (16) and fins (12), and aluminum tubes (11) manufactured separately by extrusion, as shown in FIGS. 2 and 3. The heat exchanger was assembled. The assembly was heated in a N ₂ atmosphere at 600 ° C. for 10 minutes to produce tubes (11) and fins (12), tubes (11) and headers (13) (14), brackets (16) and headers (13). Each joint of (14) was brazed. Then, the spread of the brazing material was observed to evaluate its brazing property. Furthermore, the brazing property was good N
o. Regarding brazed products of 4, 6, 9, 12-18, JI
Salt spray according to SZ2371 was performed for 1000 hours, and the corrosion state of the core material (51) of the fins (12), the headers (13) and (14) and the bracket (16) was examined to evaluate the corrosion resistance. The results of these tests are shown in Table 2.

[0026]

[Table 2] As is clear from Tables 1 and 2, Al brazing sheets I and II (Nos. 4, 6, 9, 12 to 1) in which a liner material (52) having a component composition according to the present invention is clad.
Fins (12) and headers (13) made from 8)
With the aluminum heat exchanger using (14) and the bracket (16), it was confirmed that each joint can be brazed well without separately supplying flux. on the other hand,
In the composition of the liner material (52), a comparative example (No. 2, where Si or flux content is larger than the range of the present invention).
7, 10, 11), the liner material (52) was cracked and the brazing property could not be evaluated. In addition, the comparative examples (Nos. 1, 3, 5, and 8) in which the Si or flux content is less than the range of the present invention, each member (1
2) Although it could be formed into (13), (14) and (16), all had poor brazing properties. Further, among the examples of the present invention, No. 1 containing Zn, In, or Sn added. It was confirmed that Nos. 12 to 18 had excellent corrosion resistance.

In the production of the liner material (52) containing the flux used in this example, an A1100 alloy having a composition different from that of the brazing material was used as a container material for filling the mixed powder of the brazing material. Alternatively, the alloy may be formed of an alloy having substantially the same composition as that of the brazing material composition or excluding the flux. If such a container is used, it can be hot-molded in the same manner as in the present embodiment, and extrusion-molded without removing the container part from the hot-pressed molded product.

[0028]

As described above, at least one of the fins, headers and brackets of the aluminum heat exchanger of the present invention is a liner which is a brazing material layer containing a flux component on at least one surface of the core material. The material is clad. Therefore, by using such a member,
An appropriate amount of flux is uniformly supplied together with the brazing filler metal to each joint without separately supplying the flux, and good brazing joining can be achieved, and the aluminum heat exchanger has excellent joining strength. Further, the time and effort required for applying the flux, which is indispensable in the conventional brazing method, are completely eliminated, and the brazing process can be simplified and the productivity can be improved. In particular, even in the manufacturing process of a large-sized laminated heat exchanger with a large number of joints, there is no additional work other than assembling each member, so simplification of the brazing process by simultaneous supply of brazing material and flux. Has a great effect.

Further, in the conventional method of applying the flux, it becomes possible to supply the flux together with the melting of the liner material to the portion such as the inner side of the header where the flux can be supplied only before the assembly. The restrictions on procedures are relaxed. Also, since it is possible to supply the necessary and appropriate amount of flux to the joint without using a large amount of flux, the problem of deterioration of the appearance quality and surface processability of the product due to residual flux due to excessive flux supply, It is possible to avoid problems such as contamination and damage in the furnace and jig.

[Brief description of drawings]

FIG. 1 is a front view of an aluminum heat exchanger according to this embodiment.

FIG. 2 is an essential part exploded view showing the method of assembling the aluminum heat exchanger according to the present embodiment.

3 is a cross-sectional view taken along line XX of FIG.

FIG. 4 is a cross-sectional view of an Al brazing sheet in this example.

[Explanation of symbols]

 11 ... Tube 12 ... Fins 13 and 14 ... Header 15 ... Heat exchanger body 16 ... Bracket 51 ... Core material 52 ... Liner material

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area F28F 21/08 9141-3L

Claims (2)

[Claims] 1. A plurality of heat exchange tubes (11) arranged in parallel, fins (12) interposed between adjacent tubes (11) (11), and each of the tubes (1).
1) A pair of hollow headers (1
3, 14) as a basic structure of the heat exchanger body (15), and a bracket (1) for mounting the heat exchanger body (15).
6), each of these members (11) (12) (13,
14) In the aluminum heat exchanger in which (16) are integrated by brazing, at least one of the fins (12), the headers (13, 14) and the bracket (16) is a core material made of aluminum ( 51) at least one side of which is lined with a liner material (52) as a brazing material layer, and the liner material (52) contains Al, Si and a fluoride-based flux, and a fluoride-based flux. Si content is 5 to 15 wt% with respect to the total content of the elements other than, and the total of the elements excluding the flux and the fluoride-based flux are mixed in a weight ratio of 98: 2 to 88:12. And an aluminum heat exchanger formed of a material having a density of 90% or more of a theoretical value. 2. A plurality of heat exchange tubes (11) arranged in parallel, fins (12) arranged between adjacent tubes (11) (11), and each of the tubes (1).
1) A pair of hollow headers (1
3, 14) as a basic structure of the heat exchanger body (15), and a bracket (1) for mounting the heat exchanger body (15).
6), each of these members (11) (12) (13,
14) In the aluminum heat exchanger in which (16) are integrated by brazing, at least one of the fins (12), the headers (13, 14) and the bracket (16) is a core material made of aluminum ( 51) a liner material (52) as a brazing material layer is clad on at least one side of 51), and the liner material (52) mainly contains Al, Si, a fluoride-based flux, and further contains Zn, At least one of In and Sn is contained, and the Si content is 5 with respect to the total content of elements excluding the fluoride-based flux.
~ 15wt%, Zn content 0.05 ~ 3wt%, In content 0.01 ~ 0.1wt%, Sn content 0.01 ~
0.2 wt%, and the weight ratio of the total of elements excluding the flux and the fluoride-based flux is 98: 2 to 88: 1.
An aluminum heat exchanger, characterized in that it is blended in a ratio of 2 and is formed of a material having a density of 90% or more of a theoretical value.