JPH067966A - Diffusion welding method - Google Patents

Abstract

PURPOSE:To reduce the joining time by executing the heating activation of an insert material inserted between the joining surfaces of the conductive material. CONSTITUTION:In the diffusion welding where materials 3,4 to be joined are brought into contact with each other, and welding is executed while the heat and pressure being applied thereto, the conductive material is used for the materials 3,4 to be joined, a thin insert material 5 (e.g. pure Ni) is inserted between the joining surfaces opposite to each other, electrification is made to the materials 3, 4 to be joined and joining is executed by performing the heating activation of the insert material 5. Where, the materials 3, 4 to be joined have only to be conductive, and not limited to the specific materials. The structure may not be ultra fine, and the shape may be complicate, and there are no limitations to the size or the external shape. In addition, the finish precision of the finished surface is not so severe as that of the conventional method, and it is not necessary to select the atmosphere such as vacuum. This arrangement reduces the joining time, and allows the diffusion welding at low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffusion bonding method in which metal materials are brought into contact with each other and pressure and heat are applied to their bonding surfaces to bond them in a solid state.

[0002]

2. Description of the Related Art A pressure to such an extent that a material is not largely deformed is applied to a bonding surface of the material, and heating is performed to a temperature not exceeding a melting point of the material, and diffusion of atoms generated at the bonding surface is used to achieve a solid state Compared with fusion welding and the like, the diffusion joining in which the joining is performed has very little deformation after joining, and is also suitable for joining between dissimilar materials. Therefore,
It is also used for joining materials that are difficult to melt weld. As shown in FIG. 2, ordinary diffusion bonding is performed by using a metal material c, which has a composition of fine crystal grains of 1 μm or less, between the pressing jigs a and b.
With d sandwiched, the joint surface is finished to an accuracy of about 0.2 μm or more with a ten-point average roughness, and the joint surfaces are brought together in a vacuum atmosphere in a vacuum container e by a pressure P and a heater h. Bonding was performed by applying heat and continuing it for 3.6 ks or longer. In addition, a technology has been newly developed in which an insert material is sandwiched between metal materials to be joined and pressure and heat are similarly applied in a vacuum atmosphere so that the joining can be performed in about 300 seconds. In this method, the finish of the joint surface may be about 1.0 μm or less, and the crystal grains of the material do not need to be fine as in the prior art.

[0003]

In the former method of the prior art, the structure must be made into fine crystal grains by thermomechanical processing or the like, and the joining surface must be finished with strict precision. Further, the treatment in this method requires a vacuum atmosphere, and since the heating is performed by a heater, there is a problem that the bonding time is long. On the other hand, the latter newly developed method is not simple because it is heated from the outside as in the prior art, and there is a limitation in the shape and size of the parts to be joined. Heating with a heater requires heating for a long time of 1.8 ks or more, and it is difficult to evenly heat parts with complicated shapes when heating with infrared rays. And the treatment in a vacuum atmosphere is required. The present invention has been made in view of the above circumstances, and an object thereof is to provide a diffusion bonding method that solves the above problems.

[0004]

In accordance with the above object, the present invention uses a conductive material as the material to be bonded in diffusion bonding in which materials to be bonded are brought into contact with each other and heat and pressure are applied thereto. The problem is solved by providing a thin insert material between the facing joint surfaces, and energizing these materials to be joined to heat and activate the insert material to perform joining.

The present invention will be described in detail below. In the present invention, the material to be joined may be any material that is electrically conductive, such as commonly used Fe,
It is Al, Mg, Ti, Ni, Zn, and various alloys based on these, and the same kind of materials may be different kinds of materials. The insert material is, for example, pure Ni, pure Cu, Ni—Cu alloy, etc.
i-50% Cu alloy or the like can be applied and is not particularly limited. That is, it is possible to use another material which has a function equivalent to these and reacts with the material to be joined, and has a thickness of 5 to 5.
Those of 200 μm are suitable. The joining surface of the material to be joined does not need to be finished with high precision as in the conventional method,
For example, emery paper need only be polished at the joint surface. That is, the ten-point average roughness may be 1.0 μm or less.
The joint surface should be degreased and washed.

FIG. 1 shows a joining procedure. Between the joining jigs 1 and 2, the material 3 to be joined and the other material 4 to be joined
And the insert material 5 is sandwiched between the material 3 and the material 4. Reference numeral 8 denotes a heating power source, which may be AC or DC and is connected to the jigs 1 and 2, respectively. The atmosphere at the time of bonding is air, inert gas (Ar,
N ₂ , H _2, etc.) or vacuum. In this way, depending on the materials to be joined, the pressure, the power supply capacity, and the energization time are selected for a predetermined time so that the materials to be joined are not deformed by the pressure. by this,
The insert material 5 is heated and activated (including melting),
A reaction occurs between the materials 3 and 4 to be bonded, and the materials 3 and 4 are bonded in a short time. In this case, since the heating of the insert material 5 does not depend on the heater from the outside, the joint surface is uniformly heated and even if the material to be joined has a three-dimensionally complicated shape, the joining can be performed. Also, insert material 5
Since the materials 3 and 4 that are in contact with this react with each other by heating, bonding is possible even if an oxide layer is formed on the bonding surface, the time required for bonding is shortened, and the degree of oxidation is It needs less. Further, by using the insert material 5, it is possible to join materials that are not fine crystals. By the method of the present invention, the bonding time required for the ordinary diffusion bonding of 3.6 ks or more was shortened to 600 s or less using the same bonding material.

[0007]

【Example】

1) JIS FCD450 and JIS
FC250 and φ20 × 30m
After processing to m, the joint surface was polished with No. 700 emery paper. After degreasing these by ultrasonic cleaning in acetone, a pure Ni insert material having a thickness of 10 μm is sandwiched in the manner shown in FIG. 1, and a pressure of about 20 MPa is applied in the atmosphere,
An alternating current of 200 V and 20 A was applied for 300 s. As a result, both can be completely diffusion-bonded, and rod-shaped members having different mechanical properties can be obtained with the bonding interface sandwiched therebetween. 2) JIS FCD450 and JIS
Using SUS304 and φ20 × 30
After processing to mm, the joint surface was ground with No. 700 emery paper. After degreasing these by ultrasonic cleaning in acetone, Ni-50% Cu with a thickness of 50 μm was prepared as shown in FIG.
Approximately 20MP in Ar atmosphere with alloy insert material sandwiched
While applying pressure a, AC current of 200V, 20A is 3
It flowed for 00s. As a result, both can be completely diffusion-bonded, and rod-shaped members having different mechanical properties can be obtained with the bonding interface sandwiched therebetween. Moreover, when the insert material was adopted, the bonding interface strength was sufficiently strong, and the diffusion transfer of carbon atoms from FCD450 to SUS304 could be suppressed to an extremely small amount. Therefore, the grain boundary embrittlement of SUS304 could be slightly suppressed.

[0008]

According to the diffusion bonding method of the present invention, the bonding material is not limited to a specific material as long as it has conductivity.
The structure does not have to be fine. Further, the bonding material may have a complicated shape, and the size and the outer shape are not so limited. The finishing accuracy of the finished surface is not so severe as in the conventional method, and the atmosphere such as vacuum does not have to be selected.
The joining time can also be shortened. Therefore, diffusion bonding can be easily performed at low cost.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an implementation point of a diffusion bonding method according to the present invention.

FIG. 2 is a diagram illustrating an implementation point of a conventional diffusion bonding method.

[Explanation of symbols]

 3,4 Material to be bonded 5 Insert material

Claims (1)

[Claims] 1. In a diffusion bonding in which materials to be bonded are brought into contact with each other and heat and pressure are applied thereto, a conductive material is used as the materials to be bonded, and a thin insert material is provided between the opposing bonding surfaces. A diffusion bonding method, characterized in that the insert material is energized and the insert material is heated and activated for bonding.