JPH07108474B2 - Brazing sheet and brazing method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brazing sheet and a brazing method using the brazing sheet, and more particularly, to a brazing sheet formed on a laminated plate having three or more layers and a core material made of a brazing material formed on an intermediate layer. A brazing method using the same.

[0002]

2. Description of the Related Art A brazing sheet, that is, a brazing sheet material is extremely useful because it is not necessary to separately supply a brazing material when brazing because the brazing material is already clad. Conventionally, an aluminum brazing sheet has been generally provided as the brazing sheet. As a conventional aluminum brazing sheet, a laminated plate is generally used in which one or both surfaces of a core material made of an aluminum alloy is clad with an Al—Si alloy as a brazing material.

[0003]

However, the conventional brazing sheet in which the brazing material is clad on the outer surface of the core material has the following inconveniences. That is, i) After brazing, the surface of the sheet formed by the brazing material becomes uneven due to melting, resulting in poor appearance. ii) Since the molten brazing material flows down on the surface of the core material,
Wax may flow to unnecessary parts. iii) In the case of vacuum brazing, the internal brazing property (brazing property inside the semi-enclosed space) is not good. That is, in the conventional brazing sheet, the metal content such as Mg evaporates from the plate surface, so the melting point of the molten brazing material changes between the outside and the inside (Mg lowers the melting point), or the semi-enclosed space has an atmosphere with a large amount of evaporated metal. Therefore, there is a problem that the external fillet is large and the internal fillet is small (in some cases, it is rarely formed). iv) Similarly, during vacuum brazing, the vacuum furnace is contaminated by evaporation of Mg and other metal elements in the brazing material. And so on.

In the field of vacuum brazing, a brazing sheet in which a thin pure aluminum is clad on the outside of the brazing material is an improvement of the conventional brazing sheet in order to enable brazing in a relatively low vacuum. Have been proposed (US Pat. No. 3,917,151). In this brazing sheet, by protecting the brazing material with a pure aluminum material, oxidation of the brazing material is prevented, thereby enabling brazing in a low vacuum. Further, in this brazing sheet, the pure aluminum material is melted together with the brazing material during the brazing, and melts into the brazing material. However, even this brazing sheet does not solve the problems i) and ii) above, and the above ii)
Although the problems i) and iv) have been improved to some extent, they still do not provide a fundamental solution.

The present invention has been made in view of the above circumstances, and is capable of eliminating the above-mentioned drawbacks, and in particular, the brazing sheet has a clean finish and can reliably perform internal brazing during vacuum brazing, and a brazing sheet. It is intended to provide a brazing method using the same.

[0006]

The invention according to claim 1 is
In a brazing sheet composed of three or more laminated plates, at least one layer of the inner core material is a brazing material, and the other layers sandwiching the brazing material have a solidus temperature higher than the liquidus temperature of the brazing material. It is characterized by using a high alloy material.

The invention according to claim 2 is the brazing sheet according to claim 1, wherein the brazing material and the other layers sandwiching the brazing material are aluminum alloys.

According to a third aspect of the invention, in the brazing sheet according to the second aspect, the core material made of a brazing material is an Al-Si alloy containing 5 to 20% by weight of Si. It is a thing.

According to a fourth aspect of the present invention, in the brazing sheet according to the second aspect, the core material made of a brazing material contains 5 to 20% by weight of Si and 0.3 to 3.0% by weight of Mg.
It is characterized by being an Al-Si-Mg based alloy contained.

A fifth aspect of the present invention is a brazing method using the brazing sheet according to any one of the first to fourth aspects, wherein an end portion of the brazing sheet and a brazing portion of the brazed member. A minute gap is formed between the brazing material and the brazing sheet to melt the brazing material, and the brazing material is used to melt the brazing material between the end of the brazing sheet and the brazing part of the brazed member. It is characterized by forming a fillet.

The invention according to claim 6 is a brazing method using the brazing sheet according to any one of claims 1 to 4, wherein a required end face for forming a plate thickness in the brazing sheet is closed. The outflow amount of the molten brazing filler metal is adjusted by.

[0012]

In the brazing sheet according to the first aspect, since the brazing material forms the inner layer of the laminated plate and is protected by the skin material, there is almost no deterioration due to corrosion of the brazing material. At the melting temperature of the brazing material, the brazing material flows out from the end surface of the sheet and forms a fillet with the brazing surface of the member to be brazed. Since the brazing material is formed in the inner layer of the brazing sheet, the skin material forms the sheet surface even after the brazing material is melted. Also, this is probably because of the surface tension between the skin material and the molten brazing material, but the molten brazing material is less likely to flow only on one side.

In the brazing sheet according to claim 2,
In addition to forming a highly versatile brazing sheet, since the brazing part comes into contact with the external environment for the first time, evaporation of the contained metal such as Mg is reduced even in vacuum brazing.

In the brazing sheet according to claim 3,
It is also possible to adjust the liquidus temperature of the brazing filler metal by effectively lowering the melting temperature of the brazing filler metal by adjusting the Si content.

In the brazing sheet according to claim 4,
In addition to the effect of the invention according to claim 3, good brazing properties can be obtained due to the getter effect of Mg.

In the brazing method using the brazing sheet according to the fifth aspect, the molten brazing material flows out through the gap to the brazing surface of the brazed member to form a fillet.

In the brazing method using the brazing sheet according to the sixth aspect, it is possible to adjust the amount of the molten braze flowing out to adjust the amount of the fillet.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of a brazing sheet according to the present invention. This brazing sheet 1A is a so-called aluminum brazing sheet, and is a plate body made of an aluminum alloy clad in three layers. The brazing sheet 1 formed in these three layers
In A, the core material 2 forming the intermediate layer is Al alloy 400
4, and the skin materials 3 and 3 sandwiching the core material 2 from both sides are both made of Al alloy 3003.

Here, the Al alloy 4004 forming the core material 2 contains 9.0 to 10.5 wt% of Si and 1.
It is an Al-Si-Mg based alloy containing 0 to 2.0 % by weight and its liquidus temperature is 591 ° C. The solidus temperature of the Al alloy 3003 forming the skin material 3 is 643 ° C.
Is. That is, the core material 2 constitutes the brazing material B of the brazing sheet 1A.

The plate thickness of the brazing sheet 1A is about 0.5 mm in this case, of which the core material 2 is 26%,
The skin materials 3 and 3 each have a plate thickness of 37%. In addition, the skin material 3 is obtained by soaking the hot-rolled material so as to prevent it from soaking into the wax, and then hot-rolled to a predetermined plate thickness, and clad-rolled with the core material 2.

Next, the operation and effect of the brazing sheet 1A will be described. The brazing sheet 1A
2 is used to create an inverted T-shaped T-joint 5 as shown in FIG. In this T-joint 5, the brazing sheet 1A is used as the standing plate 5A, and the bottom plate 5B is made of Al alloy 3003.
And Both the standing plate 5A and the bottom plate 5B have a size of 0.5.
It is × 25 × 50 (mm).

For comparison, as shown in FIG. 4, a T-joint 5'was similarly prepared by using a brazing sheet 1'having a conventional structure as the standing plate 5A '. The brazing sheet 1 ′ having the conventional structure is obtained by cladding the core material 2 with an Al alloy 3003 and the skin materials 3 and 3 with an Al alloy 4004 in three layers. That is, in this brazing sheet 1 ', the skin materials 3 and 3 are the brazing material B. Further, the clad ratio of this brazing sheet 1'is 74% for the core material 2 and
Are both 13% each.

Both brazing conditions are 5 × 10 ^-5 Torr.
Was heated to 605 ° C. at a vacuum degree of 5 minutes, held for 5 minutes, and then cooled. When manufacturing the T-joint 5 using the brazing sheet 1 according to the present invention as the standing plate 5A, the end surface 1 of the brazing sheet 1 to be brazed
A slight gap 6 is provided between a and the brazing surface of the bottom plate 5B.

Comparing the two completed T-joints 5 and 5 ', as shown in FIG. 3 and FIG.
A smooth and continuous fillet 7 was formed between the lower ends of A and 5A 'and the upper surface of the bottom plate 5B. In addition, both T joints 5,
Table 1 shows the dimensional comparison results after finishing 5 '.

[0025]

[Table 1]

As shown in Table 1, in the case of such a T-joint, there was no difference between the two in the formation of the fillet 7, but the evaporation amount of Mg contained in the brazing filler metal B was determined by the brazing according to the above embodiment. The number of T-joints 5 using the sheet 1A is smaller (obvious from Examples described later). Further, comparing the surfaces of the two standing plates 5A and 5A ', the standing plate 5A made of the brazing sheet 1 has a better appearance. In addition, from Table 1, both brazing sheets 1A and 1 '
In both cases, the brazing filler metal B occupies the same proportion of the total plate thickness, but it is understood that the brazing sheet 1A according to the above-described embodiment in which the core material 2 is the brazing filler metal B has a larger plate thickness after brazing.

In the T-joint 5 using the brazing sheet 1A as the standing plate 5A, the gap 6 is provided between the end surface 1a of the brazing sheet 1A and the brazing surface of the bottom plate 5B as described above. This is because the brazing filler metal B forming the core material 2 as the intermediate layer is melted and flows out from the gap 6 to the outside by the capillary phenomenon. As described above, the gap 6 may be of a size that allows molten wax to flow out. In actual work, if the brazing sheet 1A is sheared or blanked, minute irregularities are naturally formed on the cut surface, so that it is not necessary to intentionally form a gap. However, since the end surface 1a becomes smooth when the end surface 1a is milled, the gap 6 is positively provided in such a case.

Next, FIGS. 6 to 11 show another configuration example according to the first embodiment of the present invention. In this example, a plurality of disk components 10 shown in FIG. 6 are connected in parallel by three strip-shaped components 11 shown in FIG. 7, and a plate-shaped component 13 shown in FIG. 8 is provided on the outer periphery of a skeleton body 12 (FIG. 9). By wrapping, a cylindrical assembly 14 as shown in FIG. 9 was created. This cylindrical assembly 1
4, the disk component 10 and the strip-shaped component 1
1 was manufactured by using a brazing sheet 1A having the same structure as that shown in the above-mentioned embodiment. Both plate-like parts 13 are A
1 alloy 3003 . For comparison, the same cylindrical assembly 14 was manufactured by using a brazing sheet 1'having a conventional structure in which the brazing material B is formed of the skin materials 3 and 3 for both parts. Both brazing conditions are 605 at a vacuum degree of 5 × 10 ^-5 Torr.
The mixture was heated to 0 ° C., kept for 5 minutes, and then cooled.

FIG. 10 shows brazing parts of the disk component 10 and the strip-shaped component 11 and the plate-shaped member 13 on the disc-shaped component 10 and the strip-shaped component 11, respectively.
It is shown about what used A. These Figure 9
Further, as shown in FIG. 10, in the case where the brazing sheet 1A is used, the fillets 7 are formed to have substantially the same size in each stage in each stage. The same applies to the inside of this cylindrical assembly 14 which is a semi-enclosed space.

On the other hand, a brazing sheet 1'having a conventional structure
In FIG. 11, the outer fillet 7 is large and the fillet is hardly formed in the inner portion of both brazing portions as shown in FIG.
Further, inside the cylindrical assembly 14, the fillet 7 in the upper part of the joint portion is small and the fillet in the lower part is large. Further, a braze on the upper side flows into the upper part of the joining portion of the disk component 10 located at the lowermost part, and a large fillet is formed.

In the present embodiment, the cylindrical assembly 14
The fillet 7 is satisfactorily formed even in the inside of the brazing filler metal because the core material 2 which is the brazing filler metal B is not exposed to the outside until it melts and oozes out to the joint portion. It can be inferred that a large amount of steam does not fill the inside of the cylindrical assembly 14.

Next, FIG. 12 shows a large number of plate-shaped members 15, 15, ... Made of a brazing sheet as shown in FIG. Here, the brazing sheet 1B constituting the plate-shaped member 15 is according to the second embodiment of the present invention, and the brazing material B is formed in three layers as the core material 2 as in the brazing sheet 1A. However, an Al alloy 4045 is used as the brazing material B that is the core material 2, and an Al alloy 30 is used as the skin materials 3 and 3.
03. Al alloy 4045 has a liquidus temperature of 590
C, Al-Si containing 9.0-11.0 wt% Si
It is a system alloy. As already mentioned, the Al alloy 300
The solidus temperature of 3 is 643 ° C. The brazing sheet 1B has a plate thickness of 1.5 mm and a clad ratio of the core material 2
Is 20% and skin material 3 is 40%. The brazing conditions were heating in N ₂ gas at 605 ° C. for 5 minutes.

As a comparative product, the skin material 3 is made of Al alloy 4045.
That is, a brazing material is used, the core material 2 is an Al alloy 3003,
Al with the same cladding ratio as the brazing sheet 1B
A lattice member 17 similar to the above was manufactured by the plate-shaped member 15 made of a brazing sheet having a conventional structure in which the alloy 4045 was 10% on each side and 20% in total. The brazing conditions are the same as above.

As a result of the above, in the lattice member 17 in which the plate member 15 is made of the brazing sheet 1B, there is no unevenness on the surface as compared with the lattice member 17 in which the plate member 15 is made of the conventional brazing sheet. It has a beautiful appearance. Also, in the case where the plate-shaped member 15 is composed of the brazing sheet 1B, there is a case where molten brazing material flows in downward and a brazing pool is generated, but the amount of the brazing sheet of the conventional structure constitutes the plate-shaped member 15. It was less than one.

FIG. 14 shows the groove portion 1 when the plate-like member 15 is manufactured by the brazing sheet 1B.
Before forming 6, 16, ..., Pure aluminum 18 is sprayed on the upper end surface 15a and the lower end surface 15b of the plate-like member 15 forming the upper surface and the lower surface of the grid 17 to close it. Then, in this way, the upper end surface 15a
The groove 16 is formed after closing the lower end surface 18b. When the grid body 17 is manufactured by the plate-like member 15, the above-mentioned brazing pool does not occur. Further, in the present embodiment, the upper end surface 15a and the lower end surface 15b are
Was sprayed by spraying pure aluminum 18, but it may be closed by another alloy or other method.

Next, FIG. 15 shows a brazing sheet according to a third embodiment of the present invention. The brazing sheet 1C is made of a laminated plate having five layers, and the core material 2 is made of Al alloy 4N04. Both sides of the core material 2 are the skin materials 3 and 3. These skin materials 3 are the first skin material 3a clad with the core material 2 and the outer skin of the first skin material 3a. It is composed of a second clad material 3b. The first skin material 3a is an Al alloy 7N0
The first and second skin materials 3b are Al alloy 3003.

Here, the liquidus temperature of the Al alloy 4 N 04 constituting the core material 2 is 579 ° C., and the solidus temperature of the Al alloy 7N01 and Al alloy 3003 constituting the skin material 3 are respectively 615 ° C and 643 ° C. Also, A
1 alloy 4N04 contains 11.0 to 13.0 wt% Si and Mg
Is an Al-Si-Mg based alloy containing 1.0 to 2.0% by weight. Also, this brazing sheet 1C has an overall thickness of 1.
5 mm, the clad ratio is 20% for the core material 2, and the skin material 3
Is 40% (of which, the second skin material 3b is 5 %).

As shown in FIG. 16, the brazing sheet 1C was press-formed into a U shape, and a plurality of holes 19 of 36φ were formed at equal intervals (intervals of 300 mm) along the longitudinal direction in the central portion thereof. Two U-shaped members 20 are made to face each other so as to stand upright, and an Al alloy 6951 is further provided in the hole 19.
A ladder-shaped assembly 22 was formed by inserting a 35φ pipe 21 (solidus temperature 616 ° C.), and vacuum brazing was performed. The brazing conditions were heating at 595 ° C. for 5 minutes in an atmosphere having a vacuum degree of 5 × 10 ⁻⁵ Torr.

FIG. 17 is a cross-sectional view showing a brazed portion of the ladder-shaped assembly 22. As shown in FIG. 17, both the inner surface and the outer surface of the U-shaped member 20 are the pipes 21.
A fillet 7 was formed neatly around the circumference of.
In the case of this example as well, exudation of the brazing filler metal B was observed from the end portion of the U-shaped member 20, but if this causes any adverse effect, the end surface of the brazing material B is sprayed or the like as already described. It is possible to prevent such a phenomenon by blocking with.

In each of the brazing sheets 1A, 1B and 1C according to the above-mentioned embodiments, the brazing filler metal B is formed in the center layer of the clad layer, but when the brazing sheet 1C has a multi-layered structure, It is also possible to form two or more layers of the brazing filler metal B in the middle part.

As described above, the brazing sheet 1
According to A, 1B, and 1C, it has a clean appearance and extremely little solder dripping to unnecessary portions. Also,
Particularly in vacuum brazing, since the amount of vapor of Mg or the like contained in the brazing filler metal B is small, a sufficient fillet 7 is formed even in the inner portion of the one having a semi-enclosed space, and sufficient brazing is performed. The strength can be secured. Further, since the generation of Mg vapor or the like is suppressed in the vacuum brazing in this way, contamination of the vacuum furnace can also be suppressed. Furthermore, since the brazing filler metal is exposed only on the end face of the sheet thickness portion, it is possible to limit the outflow amount of the molten braze by closing the end face of the sheet, and it is also possible to adjust the fillet amount by this. is there.

A brazing sheet according to the present invention,
Particularly, in the aluminum brazing sheet as shown in each of the above-mentioned examples, it is desirable that the Si content of the Al-Si alloy forming the brazing filler metal B is in the range of 5 to 20% by weight. This is because Si has a function of lowering the melting point of aluminum within a certain addition amount range, and if the content is less than 5% by weight, the action is not sufficiently exhibited,
Further, if it exceeds 20% by weight, it acts to increase the melting point of Al. Al alloys that meet such conditions include, in addition to the above 4045, 4343, 4045, 414.
5, 4047 etc.

Further, Al-S which constitutes the brazing filler metal B
The content of Mg in the i-Mg-based alloy is preferably in the range of 0.3 to 3.0% by weight for the following reason.
Since Mg is a metal that oxidizes more easily and has a higher vapor pressure than aluminum, it evaporates immediately before the brazing temperature, destroys the oxide film covering the surface of the brazing material, and removes trace moisture or oxygen molecules in the atmosphere. Working (getter effect)
Have. That is, if the Mg content is less than 0.3% by weight, this effect is not sufficiently exhibited, and if it exceeds 3.0% by weight, the amount of Mg vapor generated during brazing is unnecessarily increased. In addition, the castability and rollability during the production of the plate material may be deteriorated. Examples of Al alloys that meet such conditions include 4003, 4005, 4N04, and the like, in addition to the above 4004.

However, in the present specification, for example, Al-
The Si-based alloy or the Al-Si-Mg-based alloy does not mean that it does not contain components other than Al and Si or components other than Al, Si, and Mg. These alloys naturally contain unavoidable impurities in addition to the above-mentioned components, and on the basis of the fact that, for example, the defect of brazing property at a low Mg content can be eliminated.
Other components such as i (bismuth) may be contained. Also,
The alloy (including pure metal) that constitutes the brazing sheet according to the present invention is not limited to the aluminum alloy, and the same can be similarly applied to the alloy that constitutes the conventionally provided brazing sheet.

In each of the above embodiments, T
Joint (Fig. 2), Combination joint of plates (Fig. 9, Fig. 1)
2), an example of forming a joint such as a pipe / plate joint (Fig. 17) has been described, but the brazing sheet according to the present invention is also suitable for other joints such as a corner joint, a seam joint, and a single-sided metal fitting. Can be applied to.

[0046]

As described above, according to the brazing sheet according to the first aspect, the brazing material is formed in the inner layer, and the brazing material in the inner layer flows out during brazing. Also has a clean surface appearance. Further, the brazing material does not deteriorate during storage because it does not come into contact with the external environment until it melts during brazing. Further, since the brazing material is exposed only on the end face of the sheet thickness portion of the sheet, it is possible to limit the outflow amount of the molten braze by closing the end face of the sheet.

According to the brazing sheet according to the second aspect, it is possible to provide a highly versatile brazing sheet having the above-mentioned effects, and in addition, particularly in vacuum brazing, the amount of vapor of Mg contained in the brazing material is small. Therefore, a sufficient fillet can be formed in the inner portion of the semi-closed space, and a sufficient brazing strength can be secured. Moreover, since the generation of Mg vapor is suppressed during vacuum brazing in this way, the contamination of the vacuum furnace can also be suppressed.

According to the brazing sheet of the third aspect, Si effectively lowers the melting temperature of the brazing material, and a brazing material suitable for the brazing sheet of the present invention can be obtained. It is also possible to adjust the liquidus temperature of the brazing material by adjusting the Si content.

According to the brazing sheet of the fourth aspect, in addition to the effect of the invention of the third aspect, good brazing properties can be obtained due to the gettering effect of Mg.

According to the brazing method of the fifth aspect, the molten braze can be surely exuded from the minute gaps, and the capillary phenomenon can be effectively generated to form a reliable fillet.

According to the brazing method of the sixth aspect, the size of the fillet can be adjusted by adjusting the outflow amount of the molten braze to the brazing portion, and the outflow of the molten braze to the unnecessary portion is prevented. It is also possible.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a brazing sheet according to the present invention.

FIG. 2 is a vertical sectional view showing a brazing state of the brazing sheet shown in FIG.

FIG. 3 is a vertical sectional view showing a T joint completed by the brazing shown in FIG.

FIG. 4 is a vertical sectional view showing a state of brazing with a brazing sheet having a conventional structure.

5 is a vertical sectional view showing the T joint completed by the brazing shown in FIG. 4. FIG.

6 is a plan view showing a disc-shaped member that constitutes the cylindrical assembly shown in FIG. 9. FIG.

7 is a plan view showing a strip-shaped member that constitutes the cylindrical assembly shown in FIG. 9. FIG.

8 is a plan view showing a plate-shaped member that constitutes the cylindrical assembly shown in FIG. 9. FIG.

FIG. 9 is a partially cutaway perspective view showing a cylindrical assembly constructed using a brazing sheet according to an embodiment.

FIG. 10 is a partial vertical cross-sectional view showing a brazing portion in the cylindrical assembly shown in FIG.

11 is a partial vertical cross-sectional view showing a brazing portion in the case where the cylindrical assembly shown in FIG. 9 is constituted by a conventional brazing sheet.

FIG. 12 is a partial perspective view showing a lattice body configured by using a brazing sheet according to a second embodiment of the present invention.

13 is a plan view showing a strip-shaped member forming the lattice shown in FIG. 12. FIG.

FIG. 14 is a cross-sectional view showing a state in which an end surface of the brazing sheet according to the second embodiment is closed.

FIG. 15 is a sectional view showing a brazing sheet according to a third embodiment of the present invention.

16 is a partial perspective view showing a ladder-like assembly constructed by using the brazing sheet shown in FIG.

FIG. 17 is a partial vertical cross-sectional view showing a brazing portion in the ladder-shaped assembly shown in FIG.

[Explanation of symbols]

 1A, 1B, 1C Blazing sheet 2 Core material 3 Skin material 6 Gap (microgap) B Brazing material

Claims (6)

[Claims] 1. A brazing sheet comprising three or more laminated plates, wherein at least one layer of the inner core material is a brazing material, and the other layers sandwiching the brazing material have a solidus temperature of the brazing material. A brazing sheet made of an alloy material having a temperature higher than the liquidus temperature. 2. The brazing sheet according to claim 1, wherein the brazing filler metal and the other layers sandwiching the brazing filler metal are aluminum alloys. 3. The core material made of a brazing material contains 5 to 5% of Si.
The brazing sheet according to claim 2, wherein the brazing sheet is an Al-Si alloy containing 20% by weight. 4. The core material made of a brazing material contains 5 to 5 Si.
Al-containing 20% by weight and 0.3 to 3.0% by weight of Mg
The brazing sheet according to claim 2, which is a Si-Mg-based alloy. 5. When brazing the end of the brazing sheet according to claim 1 to a member to be brazed, the end of the brazing sheet and the brazing part of the member to be brazed A minute gap is formed therebetween, and the brazing material is melted by heating at least the brazing sheet, and a fillet is formed between the end portion of the brazing sheet and the brazing portion of the brazed member by the brazing material. A brazing method using a brazing sheet characterized by forming. 6. When brazing the end of the brazing sheet according to claim 1 to a member to be brazed, the brazing sheet is melted by closing a required end face forming a plate thickness. A brazing method using a brazing sheet, characterized in that the outflow amount of the brazing material is adjusted.