JPH05220583A - Joining method of metallic member - Google Patents

Abstract

PURPOSE:To reduce the heating time of the solid phase joining by locally increasing the carbon contents of the surface to be joined of metallic members. CONSTITUTION:The grease of 5-200g/cm<2> is coated to or the carbon of 1-3mum in thickness is fixed to at least one of the surfaces to be joined of metallic members 12, 14. The metallic members 12, 14 are pressed in the direction of the arrow in a vacuum container 10, and the area around the surfaces to be joined is locally heated by a high frequency induction coil 20. The grease is decomposed by heating, and a large volume of carbon is produced, and the carbon is diffused from the surfaces to be joined into the metallic members 12, 14. This allows the atoms to be mutually diffused, completing the joining in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-phase bonding method in which metal members are heated in a state of being in pressure contact with each other to bond them together in a solid-phase state.

[0002]

2. Description of the Related Art Solid-phase bonding is known in which a pair of metal members are bonded to each other without melting and without being significantly deformed in a solid-phase state. Since such solid-phase joining can be performed without shape deformation, it has a feature that a structure having a desired dimensional accuracy can be precisely manufactured.

[0003]

By the way, in the above-mentioned solid-phase bonding, in the state where the metal members are pressed against each other at a relatively low pressure of about 0.1 to 0.5 kg / mm ² , the melting point of the metal members is higher than the melting point of the metal members. It is continuously heated at a low predetermined temperature for a predetermined time, but since the heating time is, for example, 10 to 20 hours or more, the efficiency of the welding work is low, the welding cost is high, and the equipment is large. Therefore, there was a drawback that it was not suitable for mass production.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid phase bonding method capable of obtaining high efficiency in solid phase bonding work.

[0005]

In order to achieve the above object, the present invention has conducted various studies, and as a result, if the carbon concentration in the joint surface is positively increased, the metal members can be made to interact with each other at a relatively low pressure. It has been found that solid state bonding can be performed in an extremely short time compared with the conventional method in the state of being pressed against. The present invention was made based on such findings.

That is, the gist of the present invention is to
A joining method for joining a pair of metal members to each other in a solid state by heating them while they are in pressure contact with each other, wherein the carbon concentration of the joining surface of the metal members is prior to the pressure contact of the pair of metal members. Is to locally increase in advance.

[0007]

With this configuration, the carbon concentration at the joint surface of the pair of metal members is locally increased in advance prior to the pressure contact between the pair of metal members.
It is considered that the carbon diffuses between the metal atoms in the metal member due to the heating under the pressure contact state, and the interface of the joint surfaces of the metal members is quickly bonded to each other due to the diffusion. Further, along with that, the joining quality can be stably obtained.

Here, preferably, the step is to apply oil or fat to at least one of the joining surfaces of the metal member, and the amount of the oil or fat to be applied is preferably 5 g. / cm ^{2 to} 200 g / cm ² .

Further, in the step, preferably, carbon is fixed to at least one of the joint surfaces of the metal member, and the carbon is 1 at the joint surface.
It is formed by vapor deposition to have a thickness of μm to 30 μm.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An application example of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic view showing a main part of a solid phase bonding apparatus. In the figure, in the vacuum container 10, a pair of rod-shaped metal members 12 and 14 held by a holding device (not shown) are moved in the directions 16 and 18 by a well-known pressing means such as hydraulic pressure or pneumatic pressure. The high frequency induction coil 20 is designed to be pressed with a predetermined pressing force.
As a result, the vicinity of the joint surfaces of the metal members 12 and 14 is locally heated.

In the case of joining using the above solid-state joining apparatus, first, a pair of metal members 12 and 14 having a mirror-polished joining surface are prepared, and the metal members 12 and 14 are fixed (not shown). The device is mounted on the device, and the joining surfaces thereof face each other and are separated from each other by a predetermined distance.
FIG. 2A shows this state. Next, oil 22 is applied to the joint surface of the pair of metal members 12 and 14, for example, the joint surface of the lower metal member 12. FIG. 2B shows this state. Then, the pair of metal members 12 and 14 are pressed with a predetermined pressing force by a pressing means (not shown).
And 18 to generate a predetermined surface pressure on the joint surfaces, and the inside of the vacuum container 10 is evacuated to a vacuum of, for example, about 10 ⁻⁴ mmHg by using a vacuum device (not shown). Then, the metal member 12 is driven by driving the high frequency induction coil 20 by a temperature control device (not shown).
The vicinity of the joint surface is locally heated to a temperature of about 70% of the melting points of 14 and 14, and this temperature is maintained for, for example, about 4 hours. FIG. 2 (c) shows this state.

At the joint surfaces of the pair of metal members 12 and 14, the above-mentioned heating decomposes the oil and fat to generate a large amount of carbon, and the carbon diffuses from the joint surfaces into the metal members 12 and 14. Therefore, the metal member 12
It is considered that the mutual diffusion of the atoms forming the and 14 is positively performed to cause the interaction between the atoms, and the bonding is completed in an extremely short time as compared with the conventional case.

Next, experimental examples by the present inventors will be described in detail. This example includes an example in which carbon is directly vapor-deposited on the joint surface in addition to the application of oil and fat for increasing the carbon concentration.

[0015] Experiment (bonding condition) the bodies: joining surface roughness of S45C steel (50 mm [phi]) nonbonding materials: 1MyumRmax following bonding temperature: 1100 ° C. bonding surface pressure: 0.3 kgf / mm ² Atmosphere: vacuum (10 ^{- 4} mmHg)

(Bonding result) Solid samples were joined under the above-mentioned joining conditions with respect to each sample having a different amount of oil and fat, a coated surface, or a vapor deposition thickness of carbon, and a vapor deposition surface, and the fracture positions and evaluation results of those samples. Is shown in Table 1. Sample No. 1 and sample N
o.2 is a comparative example in which solid phase bonding was performed without adhering oil and fat and carbon. In sample No. 1, since the fracture position when fractured by applying a tensile load to the joined sample is the base material, the joint strength of each sample was satisfactory. Since the time is twice as long as the others, the comprehensive evaluation of sample No. 1 is marked with a triangle. Application amount in the range of Sample No. 3 to Sample No. 6 (5 to 20
At 0 g / m ² ), the bonding time is 4 hours, which is a great improvement over the conventional one and the bonding strength can be obtained. But the sample
As shown in No. 7 and Sample No. 8, when the total amount of the oil / fat applied was 300 g / m ² or more, sufficient bonding strength could not be obtained in this bonding time. It is considered that excess carbon remains on the joint surface.

When the carbon deposition thickness is 0.5 μm, a sufficient bonding strength cannot be obtained with a bonding time of 4 hours as shown in sample No. 10, but as shown in sample no. A satisfactory joining strength can be obtained with the joining time of. However, since the bonding time is twice as long as the others, the comprehensive evaluation of sample No. 9 is marked with a triangle. Sample No.1
In the vapor deposition thickness (1 to 30 μm) in the range of 1 to Sample No. 14, the bonding time is 4 hours, which is significantly improved from the conventional one and the bonding strength can be obtained. However, as shown in sample No.15 and sample No.16, the total carbon deposition thickness is 4
When it was 0 μm or more, sufficient bonding strength could not be obtained in this bonding time. It is considered that this is also because excess carbon remains on the joint surface.

[0018]

[Table 1]

According to the above solid phase joining method, the carbon concentration of the joining surface of at least one of the pair of metal members 12 and 14 can be increased prior to the pressure welding by the pair of metal members 12 and 14. Therefore, the carbon on the bonding surface diffuses into the metal members 12 and 14 during the bonding period, and the interaction between the atoms of the pair of metal members 12 and 14 is promoted in connection therewith, so that the efficiency of the bonding work is improved. Be improved. Moreover, as a result of the solid-phase joining being promoted at the joining surfaces of the pair of metal members 12 and 14, stable joining quality can be obtained.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in the above-described embodiment, the carbon concentration is increased by applying oil or fat on the joint surfaces of the metal members 12 and 14 or by vapor depositing carbon. The carbon concentration of the joint surface may be increased by applying the above-mentioned treatment, an organic adhesive containing carbon may be applied, or a sheet containing a sufficient amount of carbon, such as a polyethylene film, may be applied to the metal member 12. They may be adhered to the joint surfaces of 14 and 14 or may be sandwiched between them. When this polyethylene film is used, it decomposes during heating to increase the carbon concentration on the joint surface before the start of solid phase joining.

Further, although the rod-shaped metal members 12 and 14 are used in the above-mentioned embodiments, they may not be rod-shaped, and the joining surface may not be a flat surface, and they may be fitted into a conical shape. It may be a curved surface such as a surface or a concave / convex spherical surface.

Further, in the solid phase bonding apparatus shown in FIG. 1 described above, the vacuum container 10 having the high frequency induction heating coil 20 inside is used, but it may be a vacuum container provided outside. The container may be filled with argon gas.

Further, in the above-mentioned experimental example, S45C steel was used as the metal members 12 and 14 which are the materials to be joined, but other ferrous materials or non-ferrous materials such as STKM13A steel pipes for machine structure may be used. Alternatively, the pair of metal members 12 and 14 may be made of different materials.

The above description is merely an embodiment of the present invention, and the present invention can be modified in various ways without departing from the spirit of the invention.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a main part configuration of a solid phase bonding apparatus to which a method of the present invention is applied.

FIG. 2 is a diagram illustrating a step of joining using a solid phase joining apparatus in FIG.

[Explanation of symbols]

 12, 14 Metal member (joint member) 22 Oil and fat

Claims (5)

[Claims] 1. A joining method, wherein a pair of metal members are heated in a state of being in pressure contact with each other so as to be bonded to each other in a solid state, wherein the metal members are joined prior to the pressure contact of the pair of metal members. A method for joining metal members, comprising the step of locally preliminarily increasing the carbon concentration on the joint surface. 2. The method for joining metal members according to claim 1, wherein the step is to apply oil and fat to at least one of the joining surfaces of the metal members. 3. The amount of oil or fat applied in the step is 5 g /
bonding a metallic component according to claim 2 which is cm ² to 200 g / cm ^2. 4. The method for joining metal members according to claim 1, wherein in the step, carbon is fixed to at least one of the joining surfaces of the metal members. 5. The method for joining metal members according to claim 4, wherein in the step, a carbon layer having a thickness of 1 μm to 30 μm is formed by vapor deposition.