JP3240211B2 - Copper-aluminum dissimilar metal joint material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention improves the joining strength of dissimilar metal joints in a structure or the like that requires joining copper or copper alloy and aluminum or aluminum alloy.
Even if heat is affected by welding or the like when attaching dissimilar metal joints to the structure, the characteristics of the dissimilar metal joints before heat influence are maintained as they are, so they can withstand a wide temperature range from high to low temperatures It relates to a joint material. For example,
When joining a container body made of copper or copper alloy as a member of an ultra-high vacuum vessel and a tubular structure such as a flange or piping made of aluminum or aluminum alloy, or conversely, a container body made of aluminum or aluminum alloy When joining a flange or pipe made of copper or a copper alloy with a pipe, even after performing high-temperature heat treatment such as heat degassing of the structure, an ultra-high vacuum inside the container and pipe can be easily achieved or maintained, and the structure The present invention relates to a copper-aluminum dissimilar metal joint material having sufficiently reliable airtightness, bonding strength, and mechanical properties.

[0002]

2. Description of the Related Art When joining copper and aluminum or a combination of these alloys directly, it is well known that an intermetallic compound is formed at the joint boundary when welding them directly, so that a stable joining state can be obtained. Absent.

[0003] Conventionally, the joining in the combination of the copper-based metal and the aluminum-based metal is performed by using a dissimilar metal joint material made of copper and aluminum (hereinafter, referred to as a dissimilar material joint) which has been previously joined by some method called a dissimilar joint. The joint between the dissimilar material joint and the structure can be directly welded between metal materials of the same system through the middle of the structure to be joined. As a manufacturing method of this dissimilar material joint, there are a roll cladding method, a diffusion bonding cladding method, an explosion pressure bonding cladding method, a friction welding cladding method, and the like, and the manufacturing method is appropriately selected according to the size and shape of the joint.

[0004] Generally, in a method other than the explosion pressure cladding method, the material to be joined or a dissimilar metal joint surface is exposed to high temperatures during the production or processing of a dissimilar joint, and thus the joint interface after joining is fragile. Producing intermetallic compounds, weakening the bonding strength between dissimilar metals, and heat-treating aluminum alloys and copper alloys may be affected by the heat input and the original material properties may be impaired Therefore, especially when it is necessary to maintain the characteristics of the material used for the dissimilar material joint, a cold joining method such as an explosive pressure bonding clad method is often used.

However, in any method for manufacturing a dissimilar material joint, when copper or a copper alloy is directly joined to aluminum or an aluminum alloy, copper and aluminum are originally poor in metallurgical compatibility, so that a stable and high-strength steel is used. It is difficult to obtain a bond, and even if a high-strength bond is obtained by good bonding, when heated to about 200 ° C. or more, fragile intermetallic compounds that appear in equilibrium in that temperature range are deposited in layers. As a result, there are problems such as a decrease in strength at the joining boundary and a decrease in airtightness. Also,
When the metal materials used for the dissimilar joint each contain an alloy component, the temperature at which the brittle intermetallic compound layer precipitates decreases, and the performance of the joint boundary required for the dissimilar joint decreases further on the low temperature side. There was such a problem.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art with respect to a dissimilar joint in which copper or a copper alloy is joined to aluminum or an aluminum alloy. In dissimilar materials by overcoming the poor metallurgical compatibility between copper and aluminum in manufacturing methods such as rolled cladding, diffusion bonding cladding, explosion bonding cladding, or friction welding cladding, which produce dissimilar joints made of aluminum and aluminum alloys Improve the joint strength of the joints and mechanical properties such as the airtightness of the joint boundary, supply dissimilar joints with stable performance, and weld the structure and dissimilar joints at the time of equipment assembly and after the equipment assembly Maintains joint performance even after high-temperature heat treatment such as heat degassing of the structure body , Copper has a mechanical performance and bonding strength and airtightness sufficiently reliable - and to provide an aluminum dissimilar material joint.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a metallurgically compatible intermediate layer as an intermediate layer when copper or a copper alloy and aluminum or an aluminum alloy are conventionally bonded. Attempts were made to solve the problem by inserting a metal material, and various studies were carried out on measures to simultaneously improve the joint strength and the high-temperature characteristics and the airtightness of the joint boundary.

As a result, titanium is inserted as an intermediate material in order to suppress the formation of brittle intermetallic compounds which are likely to be generated when joining dissimilar joints due to direct joining of copper and aluminum or when they are exposed to high temperatures. As a result, it was found that a dissimilar joint having uniform and good characteristics was obtained, and the present invention was completed.

That is, the present invention is based on copper or its alloy.
And a member made of aluminum or its alloy
However, through the titanium layer, roll cladding, diffusion bonding
Cladding method, explosion bonding cladding method, friction welding
Characterized by being joined by any of the following methods
The present invention relates to a copper-aluminum dissimilar metal joint material .
Hereinafter, the present invention will be described in detail.

[0010]

By inserting titanium as an insert material between copper and aluminum, which are dissimilar metal materials, it is possible to avoid direct joining of copper and aluminum. Precipitation of intermetallic compounds (γ ₂ phase, ζ ₂ phase, η phase, θ phase, etc.) can be prevented. Also, by inserting titanium in the middle of these metals, copper and titanium and aluminum and titanium are directly joined, and about 40% at the boundary between copper and titanium.
An intermetallic compound such as TiCu or TiCu ₃ is generated when heated at 0 ° C. or higher, and an intermetallic compound such as TiAl or TiAl ₃ is generated at a boundary between aluminum and titanium when heated at about 350 ° C. or higher. As compared to the case where copper and aluminum are directly joined, such as when a compound is produced, the deposition temperature of intermetallic compounds produced at the boundary is increased, and a stable joint surface with high strength can be obtained even at relatively high temperatures. .

Further, since the brittle intermetallic compound layer deposited at the joint between copper and aluminum is hard and brittle, a fine crack is easily generated by a small external force such as working. When the joint boundary is exposed to the inner and outer surfaces of the vacuum vessel simultaneously when used for dissimilar material joints for piping, etc. It was difficult to achieve an ultra-high vacuum inside the container and maintain the reached degree of vacuum due to a crack that caused a leak, so it was not possible to secure airtightness. By inserting titanium, precipitation of these fragile intermetallic compounds can be suppressed, and sufficient airtightness can be ensured.

Referring specifically to the drawings, FIG.
1 is a schematic cross-sectional view of a copper-aluminum dissimilar metal joint material laminated in a plate shape showing the basic concept of the present invention, wherein a first layer made of copper 4 or copper alloy 5 and a second layer made of aluminum 1 or aluminum alloy 2 3 shows a copper-aluminum dissimilar metal joint material having a three-layer structure of copper or a copper alloy and titanium and aluminum or an aluminum alloy in which a third layer made of titanium 3 is joined so as to be integral with the third layer in the middle.

FIG. 2 is a cross-sectional schematic view of a copper-aluminum dissimilar metal joint material laminated in a tubular shape, and shows copper 4 or copper alloy 5.
Or a three-layer structure of copper or copper alloy and titanium and aluminum or aluminum alloy in which a titanium layer 3 is joined over the entire surface between an inner layer or core material made of aluminum 1 or aluminum alloy 2 and an outer layer made of these dissimilar metals. 1 shows a copper-aluminum dissimilar metal joint material composed of:

FIG. 3 is a schematic cross-sectional view of a copper-aluminum dissimilar metal joint material laminated in a plate shape, in which a copper alloy 5 or an aluminum alloy 2 of the same system is further integrated on the outside of a copper or aluminum layer. 4 shows a copper-aluminum dissimilar metal joint material composed of four or five layers joined as described above.

[0015]

The present invention will be specifically described below with reference to examples. Example 1 An oxygen-free copper plate (C1020P) having a thickness of 30 mm and a titanium plate (TP) having a thickness of 2 mm were formed by an explosion pressure bonding cladding method.
28C) and a 10 mm-thick aluminum plate (A11
00P) to produce a clad material composed of three layers laminated in this order. Explosion pressure bonding is performed twice for each joining of materials. First, a titanium plate is joined to an oxygen-free copper plate to form a two-layer clad material, and then an aluminum plate is joined to the titanium side of this clad material. Thus, a three-layer clad material was obtained.

The state of the clad material as it was exploded and pressed and the bonding state after heating and holding at 450 ° C. for 1 hour were examined. First, a round bar tensile test piece having a parallel part diameter of 6 mm was sampled so as to have a central axis in the thickness direction of the clad material, and a titanium plate having a thickness of 2 mm was positioned at the center of the parallel part of the test piece. Finished by machining. As a result of conducting a tensile test using this test piece, it was found that 125 to 125
It shows a tensile strength of 140 N / mm ² , and all fractures are A1
It occurred inside 100 materials. The heat-treated material exhibited a tensile strength of 80 to 100 N / mm ² , and all fractured inside the A1100 material.

In this round bar tensile test, despite the tensile load acting in the plate thickness direction, no cracking or peeling occurred at the joint interface between dissimilar metals located in the parallel portion, and the joint interface was A1100. It was demonstrated that it was stronger than the material strength.

Next, an outer diameter of 60 mm and an inner diameter of 50 m
A ring-shaped dissimilar material pipe having a length of m was machined, and a helium leak test was performed by a vacuum envelope method around the joint interface to investigate airtightness. As a result, in each of the specimens, the leak amount was determined by the minimum detectable leak amount of the helium leak tester used (2.0 × 10 ⁻¹¹ atm · cc / sec).
c) It was proved that the joint interface of the dissimilar joint pipe had sufficient airtightness even after the heat treatment.

Example 2 A tough pitch copper plate (C1100P) and a titanium plate (TP28C) and an aluminum rod (A1050B) were used in parallel with the friction welding cladding method and the explosion pressure bonding cladding method.
A clad material composed of three layers laminated in the order of D) was manufactured. When manufacturing the clad material, firstly, make the plate thickness 50mm
A 2 mm thick titanium plate was joined to one side of the tough pitch copper plate by an explosion pressure cladding method to form a two-layer clad material, which was then processed into a 70 mm diameter round bar having a central axis in the thickness direction. Next, an aluminum rod having a diameter of 70 mm and a length of 200 mm was joined to the titanium surface of the cut out round bar by a friction welding cladding method to produce a clad material composed of three layers using titanium as an intermediate material. The clad material manufactured in this way is processed into a ring-shaped dissimilar joint pipe having an outer diameter of 60 mm and an inner diameter of 40 mm so as to coincide with the central axis of the material in order to remove a defective bonding part peculiar to the friction welding method. Investigations were made on the as-bonded state and the bonded state after heating and holding at 450 ° C. for 1 hour.

First, a round bar tensile test piece having the same shape as that described in Example 1 was manufactured from a ring-shaped material in the same manner, and a tensile test was performed. As a result, in the as-joined state, it exhibited a tensile strength of 120 to 130 N / mm ² , and the fracture occurred inside the A1050 material away from the joint boundary.
The heat-treated materials exhibited a tensile strength of 80 to 100 N / mm ² , and all of them broke inside the A1050 material.

Next, the state of as-joined state and 450 ° C.
Joining of dissimilar metals to a dissimilar joint pipe processed from a material heated and held for a time into a ring shape having the same dimensions as in Example 1 with an outer diameter of 60 mm and an inner diameter of 50 mm with the same method as in Example 1 A helium leak test centered on the interface was performed. As a result, each leak amount was equal to or less than the minimum detectable leak amount (2.0 × 10 ⁻¹¹ atm · cc / sec) of the helium leak tester used in any of the test pieces, and even after the heat treatment. It was proved that the joint interface of the dissimilar joint pipe had sufficient airtightness.

Comparative Example 1 For comparison, a clad plate consisting of a 30 mm-thick oxygen-free copper plate and a 10 mm-thick two-layer clad plate was produced by an explosion pressure bonding method in the same manner as in Example 1, and a titanium plate was inserted in the middle. In order to compare with the characteristics of the three-layer clad material, the state of explosion pressure bonding and the bonding state of the clad material heated and maintained at 450 ° C. for 1 hour were examined.

First, a tensile test of a round bar having the same shape as in Example 1 was conducted for the tensile strength of the clad material in the thickness direction. As a result, the test piece in the state of the
A tensile strength of 130 N / mm ² was exhibited, and the fracture was A1100.
It occurred inside the material. The heat-treated material is
Some of the test pieces were broken from the joint interface when processing the test pieces, but those subjected to the tensile test showed 40 to 60 N /
It showed a tensile strength of mm ² , most of which broke at the joint interface.

Next, the state of explosion pressure bonding and 450 ° C.
From the clad material after heating and holding for 1 hour into a ring-shaped dissimilar joint pipe having the same shape as the dimensions shown in Example 1,
A helium leak test centered on the joint interface between dissimilar metals was conducted using the same method.As a result, the leak rate of the dissimilar joint pipe processed from the state of explosion pressure bonding was the minimum of the helium leak tester used for all test specimens. detectable leakage amount ^{(2.0 × 10 -11 atm · cc} / sec) or less which was but about 10000 times more amount of leakage from the dissimilar joint tube machined from a material that has been subjected to the heat treatment (2.0 × 10 ^{- 7} atm
Cc / sec) was detected.

Comparative Example 2 For comparison, a diameter of 70 m was measured by a friction welding cladding method.
m, an aluminum bar (A105) having the same diameter as a tough pitch copper bar (C1100R) having a length of 50 mm and a length of 200 mm.
0BD). In order to compare the characteristics of this clad material with those of the three-layer clad material in which titanium was inserted as shown in Example 2, the state of friction welding and the bonding state of the material heated and held at 450 ° C. for 1 hour were examined. The investigation for comparison was conducted in Example 2.
In order to remove defective joints peculiar to the friction welding method, an outer diameter of 60 mm and an inner diameter of
mm was performed on the material processed into a ring shape.

First, a round bar tensile test piece having the same shape as that described in Example 2 was sampled in the same manner and subjected to a tensile test. As a result, 120-130 in the state of friction welding
It exhibited a tensile strength of N / mm ² , and the fracture occurred inside the A1050 material at a position away from the joint boundary. Some of the heat-treated materials broke from the joint interface when processing the test pieces as in Comparative Example 2, but the test pieces subjected to the tensile test showed a tensile strength of 40 to 50 N / mm ² . The fractures were all generated from the joint interface.

Next, a ring-shaped dissimilar material joint pipe having the same shape as the dimension shown in Example 2 was processed, and a helium leak test was conducted centering on the joint boundary. As a result, the leak amount of the dissimilar joint pipe processed from the state of friction welding is the minimum detectable leak amount (2.0 × 10 ⁻¹¹ atm · cc / sec) of the helium leak tester used in each test piece.
Although it was as follows, the leak amount (about 2.0 × 1) was approximately 10,000 times from the dissimilar joint pipe processed from the heat-treated material.
0 ^-7 atm · cc / sec) was detected.

[0028]

As described above, according to the present invention, the copper-
Aluminum dissimilar joints can be formed by direct joining of dissimilar metals constituting the dissimilar joint itself to copper and titanium and aluminum and titanium.
Precipitation of brittle intermetallic compounds generated at a relatively low temperature of ° C. can be avoided, and the precipitation temperature of intermetallic compounds generated at the junction boundary can be raised to about 350 ° C. Therefore, the temperature conditions during the production of dissimilar joints can be set to a relatively wide range up to a relatively high temperature side. It can ease manufacturing conditions such as heat restrictions and accompanying material regulations, and also heat input during welding when assembling equipment loaded on dissimilar joints, and heat degassing processing performed on vacuum equipment after assembly, etc. Therefore, it is possible to provide a dissimilar joint having sufficiently reliable mechanical properties, bonding strength and airtightness even after the thermal influence is applied.

Further, the copper-aluminum dissimilar material joint according to the present invention is to allow the heat effect of welding at the time of joining the structure and the dissimilar material joint, etc., to a relatively high temperature which is exerted on the joining boundary portion. Therefore, the selection range of the welding method and the setting range of the welding condition can be set widely, and when the space for joining the structures is narrow, the length of the dissimilar material joint can be shortened. Furthermore, it is not necessary to dissipate heat radiation grooves on the outer surface of dissimilar joints provided to reduce the effect of welding heat. become able to.

Further, when the dissimilar joint according to the present invention is used as a dissimilar joint for piping or a flange of a vacuum vessel, etc.
Due to the improvement of high temperature properties of dissimilar joints, the heating temperature was reduced to about 35.
Since the temperature can be set to a relatively high temperature of up to 0 ° C., the processing time can be shortened and an ultra-high vacuum can be easily reached.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a copper-titanium-aluminum dissimilar metal joint material,

FIG. 2 is a schematic cross-sectional view of a dissimilar metal joint material in which copper-titanium-aluminum is laminated in a tubular form;

FIG. 3 is a schematic cross-sectional view of a dissimilar metal joint material having a copper alloy layer further outside copper of the joint material shown in FIG. 1 and further having an aluminum alloy layer outside aluminum.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum 2 Aluminum alloy 3 Titanium 4 Copper 5 Copper alloy

Claims (2)

(57) [Claims] 1. A member made of copper or an alloy thereof and a member made of aluminum or an alloy thereof are rolled through a titanium layer, and are subjected to a rolling cladding method, a diffusion bonding cladding method, and an explosion.
Either crimping cladding or friction welding cladding
A copper-aluminum dissimilar metal joint material characterized by being more joined. 2. A member made of copper or an alloy thereof or a member made of aluminum or an alloy thereof has a corrosion-resistant structure or a high-strength alloy layer of the same system on a surface opposite to a bonding surface with the titanium layer. Claim 1
The copper-aluminum dissimilar metal joint material as described in the above.