JPH05245655A - Joining method for metallic member - Google Patents

Abstract

PURPOSE:To obtain a high-quality joined part by providing at least one groove having a specified sectional area on the joined surface of at least one of metallic members and supplying an excessive amount of insert material filled in the groove. CONSTITUTION:The insert material is arranged between a pair of metallic members 1 and the surface of the metallic members 1 are joined by brazing, diffusion joining, etc. In this case, at least one groove 2 having a sectional area of 1mm is provided on the joined surface of at least one metallic member 1. The amount of supplied insert material must fill the groove 2 excessively with the molten insert material. The arrangement of the groove 2 may be in a parallel line form, a check line form, a concentric form or a spiral form, etc. A triangle, a square or a semi-circle, etc., can be used for the sectional shape of the groove 2. In this way, non-defective and high-quality joined part can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to surface bonding of metal members by brazing, liquid phase diffusion bonding or the like, and more particularly to a method for bonding metal members having a relatively large bonding area.

[0002]

2. Description of the Related Art It is well known that brazing and liquid phase diffusion bonding are widely used as a method for bonding metal members. These methods can achieve high efficiency and high quality by simultaneously joining in a short time and forming a stable fillet even when the aluminum heat exchanger has complicated and many joining points, for example. It is an excellent joining method that is possible.

However, when relatively wide surfaces are joined to each other, a large joining defect is likely to occur, and it is very difficult to join without removing defects such as voids. In brazing and liquid phase diffusion bonding, the following points can be mentioned as the main points at which defects such as voids (non-bonded surfaces) do not occur when bonding with a wide bonding surface.

(1) Before the insert material flows, the oxide film on the joint surface is removed to clean the joint surface. That is, when bonding is performed in the atmosphere, the flux is sufficiently flowed to remove the oxide film, and when the bonding is performed in an atmosphere gas or in vacuum, the pretreatment cleaning is completely performed. (2) Place a uniform and sufficient amount of insert material between the joint surfaces. That is, in general, when the insert material is in a molten state, it penetrates into a narrow gap due to a capillary phenomenon and spreads. Therefore, the insert material may be arranged only at the end of the joint surface. However, when the joint surface is large, defects often occur due to insufficient spread of the insert material, although this is related to the wettability between the base material and the insert material.

(3) To maintain a uniform gap between the joint surfaces. (4) When using flux, discharge the flux out of the joint surface. (5) Uniformly heating the joining member to an appropriate temperature above the melting point of the insert material. That is, when the temperature distribution of the joining member becomes non-uniform, the insert material moves to the high temperature side, and defects easily occur on the low temperature side. Etc.

The inventor of the present application repeated experiments on wide surface bonding, and found that, among the points described above, the quality of the uniformity of the bonding surface gap mentioned in (3) had a great influence on the occurrence of bonding defects. I figured it out. That is, the gap between the joint surfaces is machined and uniform at the beginning of assembly of the joint member, but during the heating process, the shape of the member, the temperature distribution, the residual stress, the pressing method of the joint surface, and the case where the members are different materials Deformation due to a difference in linear expansion coefficient or the like occurs and the gap between the joint surfaces changes.

When the insert material is melted in the heating step, the insert material in the substantially uniformly formed gap is discharged to the outside of the joint surface due to the pressing force of the joint surface. If the member is then thermally deformed and a large gap is generated inside the joint surface, that portion requires more insert material, but the melted insert material has already become a thin film, and The extra insert material has already been pushed out of the joint surface and cannot return to the joint surface. That is, a shortage of insert material (shortage of molten metal) occurs inside the joint surface, and large void-shaped defects occur.

Various studies have already been made to solve this problem. For example, JP-A-62-29226
"Hard brazing method" described in Japanese Patent Laid-Open No. 1-62, in which the surface roughness or warpage of the joint surface is regulated to a value at which the brazing filler metal is sufficiently filled due to strong capillary action.
JP-A-156069 discloses a brazing material in which at least one of the metal members to be joined is curved and superposed, and a brazing material is supplied to the gap, and then the metallic member is wetted while correcting the deformation. "Brazing method" for solidifying metal, "Metal joining method" described in Japanese Patent Laid-Open No. 63-20159, in which a pin or a washer or the like is interposed between the joining surfaces to control the gap and the joining is carried out. 1
JP-A-142454 discloses a closed-loop groove formed on a joint surface, a brazing material is placed between the joint surfaces other than the groove to heat the brazing material, and the brazing material is spread between the joint surfaces. "Cooling plate for sputtering target"
Etc.

[0009]

Even in the prior arts described in the above publications, it was possible to suppress the occurrence of void defects due to a shortage of the insert material inside the joint surface to some extent. However, the gap between the joint surfaces to be controlled is a very small value of several μm to several tens of μm, and it is difficult to completely prevent defects by the conventional measures described in the above items. In the method described above, when the size of the groove is large, there is a possibility that the brazing material will flow unevenly into some of the grooves, causing a portion where the brazing material is insufficient on the joint surface.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for joining metal members, which has a simple structure and which suppresses the occurrence of void defects due to insufficient insert material inside the joining surfaces. I am trying.

[0011]

The above object can be achieved by the method for joining metal members described in the claims. That is, at least one groove having a cross-sectional area of 1 mm 2 or less is formed on the joint surface of at least one metal member.
This is a method for joining metal members in which the number of the insert members to be provided is equal to or more than the amount of the insert material to be supplied so that the melted insert material can sufficiently fill the groove. Hereinafter, the operation and the like of the present invention will be described based on Examples.

[0012]

1 to 7 are views showing the shapes of grooves in a method for joining metal members according to the present invention, FIGS. 1 to 4 are views showing examples of the arrangement of grooves, and FIGS. 5 to 7 are sectional shapes of the grooves. It is a figure which shows the example of. 1 to 7, 1 is a metal member and 2 is a groove.

First, the groove 2 formed on the joint surface of the metal member 1.
In accordance with the size of the joint surface, it is preferable that a plurality of grooves be provided rather than one groove, and the pitch of the grooves 2 is preferably about 5 to 30 mm. Further, the arrangement of the grooves 2 is a parallel streak shape as shown in FIGS.
The shape may be a lattice streak shape, a concentric circle shape, a spiral shape, or the like. The cross-sectional shape of the groove 2 may be a triangle, a quadrangle, a semicircle, or the like as shown in FIGS. 5 to 7, but in order to prevent formation of a cavity inside the groove 2, a fillet is formed at the meeting portion with the joining surface. Triangles and semicircles that are easier to form are better.

The cross-sectional dimension of the groove 2 may be a size capable of supplying the insert material lacking in the gap between the joint surfaces, and in order to save the insert material filling the inside of the groove 2, the cross-sectional area is 1 m.
m ² or less is desirable. For example, if a large size such as a 5 mm × 5 mm square is used, the amount of insert material to be supplied increases and the assembly accuracy of the members deteriorates.
Uniform filling of the groove 2 tends to be difficult, and the same result as that of the non-bonded portion is generated on the entire bonded surface, which is not preferable.

When the insert material is melted in the heating step in the joining, the excess insert material is discharged to the outside of the joining surface due to the pressure of the joining surface. However, as in the present invention, the groove 2 is formed in the joining surface. When the amount of the formed insert material to be supplied is equal to or more than the amount that the melted insert material can sufficiently fill the groove 2, the excess insert material is first filled in the groove 2 and only the excess insert material is further filled. It will be discharged out of the joint surface.

When the metal member 1 is thermally deformed by the heating of the metal member 1 for maintaining the molten state of the insert member, the conventional technique causes a shortage of the insert member and causes large defects such as voids. However, in the present invention, since the spare reserve of the extra insert material is held inside the groove 2, the insert material is supplied from the inside of the groove 2 to the joint surface with a small gap by the capillary phenomenon, so that the defect of the joint surface can be prevented. Generation is prevented and a good joint surface is obtained.

It is theoretically conceivable that a shortage of the insert material supplied to the joint surface may occur inside the groove 2, but the thickness of the gap is very small as described above, and the groove 2
Even if a cavity is formed inside, it is a fine one, and if evaluated from the characteristics supplied to the joint surface, that is, strength, thermal conductivity, electrical conductivity, etc., it is of no problem. However, if vacuum sealing characteristics are required for the circular joint surface, it is desirable to use concentric grooves 2 for safety.

The inventor of the present application actually conducted a test based on the method of joining metal members described above. The results are shown in Tables 1 to 3. First, the test No. 1-4 are
200mm × 200m between 20mm thick copper (Cu) plates
m is overlaid and joined, the insert material is BAg-8 6
A foil with a thickness of 0 μm is placed between the bonding surfaces, and it is 1 × 10 ⁻⁴ Torr.
The bonding was performed at 820 ° C. in the vacuum atmosphere.
Test No. In Nos. 1 and 2, the plate set on the lower side had a value of 0.
It is provided with small triangular grooves of 4 mm and 0.6 mm. In No. 3, a large square groove of 5 mm square is provided. As a result of performing an ultrasonic flaw detection test on the entire surface of the bonded portion, test No. No defects were found in Nos. 1 and 2, and test No. In No. 3, the groove was not filled and a cavity was found along the groove. Test No. In No. 4, a large void was generated on the joint surface.

[0019]

[Table 1]

Test No. of Table 2 5 and 6 are 2 respectively
Copper (Cu) plate with a thickness of 0 mm and a diameter of 200 mm and titanium (T
i) Bonding of plates, and test No. 5 is provided with a concentric circular groove shown in the same table on the titanium side, and the titanium plate is set downward, and the case of Table 1 is similarly used as an insert material B
Bonding was performed using a Ag-8 solder having a thickness of 60 μm. As a result, the test No. with the groove was provided. In No. 5, there was no defect and there was no groove. A void was generated in No. 6.

[0021]

[Table 2]

Test No. 3 in Table 3 20m for 7-9
Aluminum (Al) plate with a thickness of m and a diameter of 200 mm and titanium (T)
i) Joining of plates. Test No. No. 7 has a concentric groove of 0.4 mm as shown in the table on both the aluminum side and the titanium side. 8 is similarly provided with a square groove of 3 mm square. The brazing material is A3003,
Vacuum brazing was performed at 600 ° C. using a brazing sheet in which A4004 having a thickness of 0.15 mm was arranged on both sides. Also in this case, the test No. with a small groove was used. In No. 7, no defect was generated and the test No. 7 with a large groove was used. In No. 8, the groove portion was left unfilled and had no groove. In No. 9, a joint having no void defect was not obtained.

[0023]

[Table 3]

[0024]

As described above, according to the present invention, as described in the above embodiment, a small groove is provided on at least one of the joint surfaces in the interfacial joining such as brazing and liquid phase diffusion joining. With a simple method, it is possible to obtain a high-quality joint without defects.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of the shape of a groove in a method for joining metal members according to the present invention.

FIG. 2 is a plan view showing an example of the shape of a groove in the method for joining metal members according to the present invention.

FIG. 3 is a plan view showing an example of the shape of a groove in the method for joining metal members according to the present invention.

FIG. 4 is a plan view showing an example of the shape of a groove in the method for joining metal members according to the present invention.

FIG. 5 is a diagram showing an example of a cross-sectional shape of a groove in the method for joining metal members according to the present invention.

FIG. 6 is a diagram showing an example of a cross-sectional shape of a groove in the method for joining metal members according to the present invention.

FIG. 7 is a diagram showing an example of the cross-sectional shape of a groove in the method for joining metal members according to the present invention.

[Explanation of symbols]

 1 metal member 2 groove

Claims (1)

[Claims] 1. A groove having a cross-sectional area of 1 mm 2 or less is formed on at least one of the joining surfaces of the metal members when the insert member is disposed between the pair of metal members and the metal members are surface-joined by brazing, diffusion joining, or the like. A method for joining metal members, characterized in that at least one or more pieces are provided, and the amount of the insert material to be supplied is set to an amount equal to or more than a quantity capable of sufficiently filling the groove with the melted insert material.