JP2545048B2 - Solid phase bonding method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state joining method, and is useful for manufacturing structural dissimilar joints (transition joints) and pipe transition joints used for cryogenic equipment, high vacuum equipment, etc. It relates to a suitable solid phase bonding method.

[0002]

[Prior Art] Among transition joints,
In particular, a composite member in which aluminum (including pure aluminum and aluminum alloy) and stainless steel or copper is joined cannot be manufactured by the fusion joining method that is a typical conventional joining method, so the diffusion joining method is applied. However, the surface of aluminum is easily oxidized,
In addition, the oxide is very stable and difficult to remove, which makes it difficult to form a reliable joint.

Therefore, when aluminum and stainless steel are to be diffusion-bonded, a method of raising the diffusion-bonding temperature to just below the melting point of aluminum can be considered in order to destroy the oxide film. However, in dissimilar metal joining of aluminum and stainless steel, when the joining temperature is raised to just below the melting point as described above, a brittle iron-aluminum intermetallic compound is formed, and a joint having sufficient reliability is formed. Impossible to do.

[0004]

For the above reasons, the transition joint is mainly manufactured by explosive welding or friction welding, although the diffusion joint has a high degree of freedom in terms of shape and dimensions. And as a result,
The current situation is that the materials and shapes are limited and expensive. In other words, in explosion pressure welding and friction welding, there are restrictions on the types of aluminum alloys that can be joined, and it can be applied only to pure aluminum that does not contain alloy components or limited types of aluminum alloys, and a combination of free materials can be selected. There is a drawback that you cannot do it. Further, since there is a limitation on the shape and size of the joining member that can be pressure-contacted, it is not possible to obtain a transition joint having a desired shape and size, and there is a limitation in manufacturing.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to join a first metal such as stainless steel and a second metal such as pure aluminum or aluminum alloy, Good bonding strength is obtained,
Moreover, it is an object of the present invention to provide a solid phase joining method that is economical and is not limited by the type of alloy, and is therefore suitable for producing a composite member such as a transition joint.

[0006]

[Means and Actions for Solving the Problems]
In the solid-phase joining method, a new surface is created by cutting and removing a surface layer containing a contaminated layer such as an oxide film of the second metal at the edge of the end portion of the joining surface of the first metal to form a new surface, When the newly-formed surface of the second metal and the second metal are pressure-welded to each other, a temperature difference is provided between the first metal and the second metal for bonding. That is, by setting the temperature of the second metal to be higher than that of the first metal, the second metal is softened at the time of construction to facilitate cutting. Further, this method is characterized by enabling the combined joining of metals, which is impossible at the time of normal temperature because the cutting and removal by the edge cannot be performed.

The setting of the temperature difference between the first metal and the second metal can be selected as follows. That is, the second
When the temperature of the metal is higher than that of the first metal, the soft metal is further softened. Therefore, the removal of the further softened second metal surface layer by the edge of the first metal should be performed more easily than at room temperature. It is possible to obtain good bondability. When the temperature of the second metal is higher than that of the first metal, even if the second metal is harder than the first metal at room temperature, the second metal surface layer can be cut and removed by the edge of the first metal, and the second metal surface layer cannot be removed at room temperature. It is possible to join in a combination that was possible. For example, oxygen-free copper (C1020)
And aluminum alloy (A5083) in combination, the aluminum alloy (A508
3) is harder than oxygen-free copper (C1020), but the aluminum alloy (A5083) is heated to a higher temperature than oxygen-free copper (C1020).
It is also possible to make 5083) softer than oxygen-free copper (C1020) for bonding.

Although the dissimilar material bonding in which the first metal and the second metal are different from each other has been described above, it is obvious that the present invention can be applied to the case of the same material bonding in which the first metal and the second metal are the same. Is.

When the temperature of the second metal is at least a temperature at which the constituent atoms of the second metal can diffuse, good results can be obtained by slow cooling after cutting. It is possible, only needs to be heated once, and construction is simple and economical. At a temperature lower than the above, micro defects may occur on the pressure-bonded surface between the first metal bonding surface and the second metal nascent surface, and a bonding portion having sufficient bonding strength may not be obtained. Diffusion heat treatment is required. Of course, the temperature at which the constituent atoms of the metal can diffuse is much lower than the melting point, and is generally about 1/2 of the melting point of the metal.
It will be about the temperature.

However, setting a temperature that is too high at the time of joining leads to deterioration of the joining strength due to the formation of intermetallic compounds on the joining surface, surface oxidation and deterioration of the material, and is not efficient in terms of construction.

By providing a temperature difference between the metals to be joined as described above, a good joint having sufficient performance as a transition joint can be obtained.
Moreover, it can be applied not only to pure aluminum but also to a high-strength aluminum alloy, and there are few restrictions on the type, shape and size of the alloy.

According to the solid-phase bonding method of claim 3, by curing a part or the whole of the first metal forming the edge in the above-mentioned bonding and using it for bonding, the second metal by the edge of the first metal is formed. Cutting of the surface layer becomes easy, and joining in a combination that has been impossible is possible. In other words, hardening, film coating, which is a conventionally known hardening method,
A part or all of the first metal is hardened by a carburizing method, a nitriding method, a strain hardening method or the like. The hardening method of the first metal can be freely selected according to the metal, and only the surface near the edge related to cutting removal may be partially hardened, but the entire surface may be hardened as long as it does not adversely affect the joining. I don't care.

Further, as in the solid phase bonding method of claim 4,
By replacing only the edge of the first metal with a dissimilar material harder than the second metal in the above joining, it becomes possible to cut the second metal surface layer by the edge of the first metal, and joining in a combination that is impossible Is possible. In other words, by replacing only the edge with a different material that is harder than the main body, it is possible to prevent the edge from being deformed, effectively remove the second metal surface layer by cutting, and enable bonding in a combination that was impossible. It will be. And about the replacement method of different materials, fusion welding, brazing, which is a conventionally known joining method,
Adhesion, mechanical joining method, etc. are conceivable, and hard dissimilar materials are not limited to metals, but also non-metal hardened materials such as ceramics are applicable.

Although it is possible to use it in the heat treatment state as it is, it is possible to facilitate the construction by performing the construction at a relatively low temperature as claimed in claim 5, and to carry out the diffusion heat treatment or the stabilization heat treatment after the construction. By adding more,
It is possible to improve the performance of the joint. Particularly in the case of a combination that requires a relatively high diffusion temperature, it is possible to lower the construction temperature by performing heat treatment after construction. The heat treatment furnace does not require selection of the atmosphere, and an inexpensive atmospheric furnace with high production efficiency can be used.

According to this method, a special atmosphere such as a vacuum or a reducing gas is not usually required at the time of application, and even if the second metal is applied in the atmosphere, the oxide film on the surface generated by heating is A new surface with no pollution is generated because it is removed by one metal, and the first metal is constructed at room temperature or at a relatively low temperature where it is not polluted by the atmosphere, so that a joint with sufficient performance can be obtained. It is possible and very economical in construction.

[0016]

Next, specific examples of the solid phase bonding method of the present invention will be described in detail with reference to the drawings.

First, Table 1 shows typical compositions of pure aluminum and aluminum alloy used as the second metal.
Pure aluminum (A1050) as non-heat treatment alloy, and aluminum alloy containing magnesium (A505)
2, A5083) and A6061 as a heat treatment alloy. The heat-treated state is all annealed material (O material) except that the heat-treated alloy A6061 is heat-treated material T6.

[0018]

[Table 1]

Table 2 shows pure aluminum, aluminum alloy, stainless steel (SUS304), and oxygen-free copper (C
1020-O) hardness at room temperature (Vickers hardness H
v, load 1 kg). At room temperature, aluminum alloys (A5052 and A5083) are oxygen-free copper (C1
020) and harder than stainless steel.

[0020]

[Table 2]

According to this method, it is possible to manufacture a plate-shaped joining member, but since the construction test of this time mainly applied the manufacturing method of the transition joint for piping, it will be described below.

FIG. 1 shows typical shapes of the first metal 1 and the second metal 2 before the joining work. The second metal 2 is usually ring-shaped, the inner surface 3 to be cut and removed is a cylindrical curved surface, and the outer surface 4 in contact with the mold has a shape including an inclination angle for draft. Then, with the edge 5 of the first metal 1 in contact with the upper surface 6 of the second metal 2, a load is applied to the end surface 7 to cut and remove the inner surface 3 of the second metal 2. That is, the inner peripheral portion of the second metal 2 is cut off by the edge 5, a new surface is formed in this portion, and the tapered side surface 9 of the first metal 1 comes into contact with this new surface. The pressure acts in a direction to bring the side surface 9 of the first metal 1 and the new surface into close contact with each other, whereby oxygen contact between the side surface 9 and the new surface of the first metal 1 is prevented, and as a result, both surfaces are joined. . The side surface 9 of the first metal 1 is a portion which becomes a joint interface with the second metal 2 after joining as described above, has a shape including an appropriate inclination angle, and is kept clean before joining.

FIG. 2 shows the arrangement of the mold 10 that supports the second metal 2 and the first metal 1 during construction. The mold 10 has an inner surface 11 having a shape including an inclination angle corresponding to the second metal 2, and has a hole at the bottom for extracting a joining member composed of the second metal 2 and the first metal 1 from the mold after the construction work. Have twelve. Second metal 2
The first metal 1 and the first metal 1 are placed in the mold 10 after being provided with an appropriate temperature difference and joined, but this time, only the second metal 2 is heated to an appropriate temperature, and the first metal 1 is kept at room temperature. It was used for bonding without heating. In addition, in this case, the second mold is previously attached to the mold 10.
The metal 2 may be placed and then heated, and the construction work may be performed with the first metal 1. Second to die 10 in advance
When the metal 2 is placed and heated, the joining member is gradually cooled by the residual heat of the die 10 even after cutting, and the diffusion heat treatment is also performed at the same time.

FIG. 3 shows a cross-section of a joining member composed of the second metal 2 and the first metal 1 after the construction work, and a cylindrical transition joint 20 manufactured by machining from the joining member. At the intermediate portion in the axial direction of the transition joint 20, the bonding interface 21 exists corresponding to the shape including the inclination angle of the first metal 1. At the bottom of the second metal 2, the burrs 22 cut and discharged from the inner surface at the edge 5 of the first metal 1 are discharged.
Is protruding.

FIG. 4 shows an example of a cylindrical transition joint 20 manufactured by machining from a joining member composed of a second metal 2 and a first metal 1. In the construction examples, the dimensions after machining are 70 mm outer diameter and 60 m inner diameter.
m and length 120 mm. The transition joint 20 has a joint interface end 23 on the outer surface side and a joint interface end 24 on the inner surface side, and a joint interface 21 having an inclination angle of 10 degrees is present in the cut cross section.

FIG. 5 shows an example in which the surface of the first metal 1 forming the edge is hardened. A case is shown in which only the outer surface of the portion 8 including the edge 5 to be cut and removed is cured from the main body 1, and the inclined portion 9 serving as the joint interface of the transition joint is only polished and not cured.

FIG. 6 shows an example in which a part of the first metal 1 forming the edge is replaced with the dissimilar metal 30. This is an example in which a portion 8 including the edge 5 is replaced with a hard dissimilar metal 30. As a joining method at the joining position 31 between the main body 1 and the dissimilar metal 30, electron beam welding, which is a fusion welding method with little thermal influence, is adopted. . Further, the slanted portion 9 serving as the joint interface of the transition joint is only polished.

By the way, as means for evaluating the soundness of the transition joint joint 21, the following three types of test inspections were conducted. 1. Penetration deep wound inspection at the joint interface between the inner and outer surfaces 1. He leak rate measurement inspection of interface 3. Room temperature tensile test using tensile test pieces taken in the axial direction

Table 3 shows a list of three types of evaluation test results for investigating the performance of the transition joint joint 21 in the material combination of the first metal 1 which is the edge forming metal and the second metal 2 which is the metal to be cut. Indicates.

[0030]

[Table 3]

As a result of the preliminary test, the one that was rapidly cooled after the construction was inferior in the degree of bonding, and the one that was gradually cooled or held in the furnace at or near the construction temperature and then gradually cooled gave a better result. Regarding the construction of, the construction was gradually cooled.

Table 3 shows the preheating temperature of the second metal 2 in each combination, the penetration deep wound test result, the He leak test result, and the room temperature tensile test result. Further, the presence or absence of replacement of the edge 5 depends on whether the first metal 1 forming the edge 5, here the edge 5 of oxygen-free copper (C1020) is made of harder stainless steel (S
US304), the preheating is performed only on the second metal 2 which is the metal to be cut for softening, and the edge 5
The first metal 1 forming the was used for bonding at room temperature without heating.

The results of the penetration deep scratch test indicate the presence or absence of a defect indication at the interface portion 21 between the inner surface and the outer surface. For those having a defect indication, the other two types of evaluation tests were not conducted as a defective joint.

As a result of the penetration deep scratch test, the He leak test was conducted only for those having no defect indication, and the leak rate was 2
Those less than × 10 ⁻¹⁰ torr · l / sec were regarded as acceptable. If the He leak test passes, the airtightness of the interface portion 21 is good, and it is an index showing the soundness of the joint portion.

Then, a tensile test was carried out at room temperature for those that passed the He leak test, and the fracture position and the nominal stress at the fracture were determined. The tensile test piece used this time has a cross section of 6
mm x 19 mm, plate-shaped, cylindrical transition
Since the joint 20 was sampled so that the axial direction was the tensile direction, the joint interface 21 had an inclination angle of 10 degrees with respect to the tensile axis. If the strength of the joint is equal to or higher than that of the base metal,
The fracture position is in the base metal, and in that case, the tensile strength of the base metal is almost the same. When the strength of the interface part is lower than that of the base material, the fracture position is the interface part and has a value lower than the tensile strength of the base material.

Table 3 No. 1 to No. 10 is stainless steel (SUS) as the first metal 1 which is an edge forming metal.
304) and pure aluminum (A1050) and aluminum alloy (A50) as the second metal 2 which is the metal to be cut.
52, A5083, A6061).
By appropriately selecting the preheating temperature of the second metal 2, the base metal is fractured on the aluminum side (pure aluminum and aluminum alloy side) which is the second metal 2, and the tensile strength is the same as the base metal strength. . However, No. 5 and No. As shown in FIG. 6, in the case of the hardest aluminum alloy (A5083) of the second metal 2 which is the metal to be cut taken up in the present invention, if the preheating temperature is too low, interface rupture occurs, but even in that case, tensile strength It is only slightly lower than the base metal strength. The heat treatment type aluminum alloy (A6061) was used as the second metal 2 as the metal to be cut. 9 and No. In the case of No. 10, the strength of the base material was lowered by heating, but the base material was fractured, indicating that the interface portion has higher strength than the base material portion.

No. 11 to No. 13 is oxygen-free copper (C1020) as the first metal 1 which is an edge forming metal,
As the second metal 2 which is the metal to be cut, pure aluminum (A
1050) is combined. Although the base metal was fractured regardless of whether or not the edge was replaced, the edge was made of harder stainless steel (SUS304). In the case of No. 13, the tensile strength was slightly higher, indicating that a more healthy joint can be stably obtained.

No. 14 to No. In comparison with the oxygen-free copper (C1020) of the first metal 1 which is the edge forming metal, the hardness of the aluminum alloy (A5052, A5083) of the second metal 2 which is the metal to be cut is reversed at room temperature,
Stable cutting is difficult even when the aluminum alloy is heated to the working temperature, and a large pressing force is required for cutting, so the case where the interface part is locally deformed is shown. No. 15 and No. Comparing No. 16, both are interface fractures,
By replacing the edges, the tensile strength is slightly increased, indicating that a more healthy joint can be stably obtained.

No. 18 to No. 21 is the case of the hardest aluminum alloy (A5083) of the second metal 2 which is the metal to be cut taken up in the present invention. Although it shows interface rupture by replacing the edge, it replaces the edge. If it is not, it can be applied even if heated up to 450 ° C due to softening, but it can be applied even at a lower temperature of 400 ° C, and a transition with a quality of the interface that passes the He leak test. Joints can be manufactured.

No. 22 to No. 24 is a first metal 1 which is an edge forming metal made of stainless steel (SUS304),
Oxygen-free copper (C1020) is the second metal 2 that is the metal to be cut
In the case of the combination, the He leak test passed, and by appropriately selecting the construction conditions, a transition joint having an interface rupture but a tensile strength of 14 kgf / mm ² or more can be used at a relatively low temperature. Can be obtained at the construction temperature of.

Table 4 shows No. 1 in Table 3. 24 shows the results when heat treatment was added after construction. 800 ° C x
As a result of performing a room temperature tensile test by the method described above after performing a heat treatment for 2 hours, a fracture surface in which the base material fracture and the interface fracture are mixed is exhibited, and the tensile strength is 6 kgf / m from immediately after the construction before the heat treatment.
m ² increased, indicating that the additional heat treatment is effective in improving strength.

[0042]

[Table 4]

In this way, a temperature difference is provided between the second metal 2 being the metal to be cut and the first metal 1 being the metal forming the edge, and the second metal 2 being the metal being cut is the metal forming the edge. By setting the temperature higher than that of the first metal 1, a transition joint having high airtightness and a joint having sufficient strength can be obtained.

[0044]

The solid phase bonding method of the present invention is constructed as described above. Therefore, according to the present invention,
A transition joint having a sound joint can be obtained, and it is possible to provide a solid-phase joining method that is economical and has few restrictions in shape and size.

Further, since the bonding method is a method in which the diffusion layer is small, it is suitable for bonding a metal such as aluminum (pure aluminum and aluminum alloy) which easily forms a brittle intermetallic compound, but usually various kinds of metals are used. It can be widely applied to various combinations of materials including the exemplified stainless steel and copper joined by diffusion bonding, and is not limited to the exemplified combinations.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an example of the shapes of a first metal and a second metal.

FIG. 2 is a partial cross-sectional view showing an example of a mold that supports a first metal and a second metal during construction.

FIG. 3 is a central vertical cross-sectional view showing an example of a cross-section of a joining member made of a first metal and a second metal after a construction work.

FIG. 4 is a partial cross-sectional view showing an example of a cylindrical transition joint manufactured from a joining member by machining.

FIG. 5 is an explanatory diagram showing a state in which the surface of the first metal forming the edge is cured.

FIG. 6 is an explanatory diagram showing a state in which a part of the first metal forming the edge is replaced with a different material.

[Explanation of symbols]

 1 First metal 2 Second metal 5 Edge 8 Edge-containing part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuji Yanagida, 3-18-21 Yukawashinmachi, Kokuraminami-ku, Kitakyushu, Kitakyushu, Fukuoka Prefecture (72) Kazuhiro Okubo, 2-9-2, Hinosato, Munakata-shi, Fukuoka (72) ) Inventor Shigetomo Matsui 3-1-1 Higashikawasaki-cho, Chuo-ku, Hyogo Prefecture Kawasaki Heavy Industries Ltd.Kobe factory (72) Inventor Takeshi Yamada 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City Hyogo Kobe Factory Co., Ltd. (56) Bibliographic references Sho 56-50581 (JP, U)

Claims (5)

(57) [Claims] 1. A solid-phase joining method for joining a first metal and a second metal in a solid-phase state, by cutting and removing a surface layer of the second metal with an edge of an end portion of a joining surface of the first metal. When a new surface is generated and the joining surface of the first metal and the new surface of the second metal are pressure-welded, a temperature difference is provided between the first metal and the second metal so that the second metal has a higher temperature than the first metal. By so doing, the second metal is softened at the time of construction. 2. The temperature of the second metal at the time of joining is
The solid phase bonding method according to claim 1, wherein the temperature is at least a temperature at which the constituent atoms of the second metal can diffuse. 3. The solid phase bonding method according to claim 1 or 2, wherein a part of the first metal including the edge or the whole thereof is hardened. 4. The solid phase bonding method according to claim 1, wherein a portion including the edge of the first metal is replaced with a different material. 5. The solid phase bonding method according to claim 1, further comprising a diffusion heat treatment or a stabilizing heat treatment.