JP2003053557A - Joining method and joining structure between dissimilar metals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bonding method and bonded structure between different kinds of metallic material which improves impact strength of a bonded part and the reliability thereof in the bonding of different kinds of material different in material characteristic. SOLUTION: In this bonded structure between different kinds of metallic material in which a first member and a second member are coaxially bonded, a bonding surface comprising a recessed part of the first member 10 made of aluminium or an aluminium alloy and a bonding surface comprising a projected surface corresponding to the recessed surface of the second member 12 made of titanium or a titanium alloy are bonded to each other by themselves by means of friction welding and the angle formed between an edge part 14 of the bonding surface of the second member 12 and a free edge 15 of the second member is made within the range of 45-88 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining structure between dissimilar metal materials, and more particularly, to a joining structure between dissimilar metal materials such as aluminum or aluminum alloy material and titanium or titanium alloy material.

[0002]

2. Description of the Related Art Conventionally, a rod-shaped or tubular dissimilar material joint is joined by a joining method such as friction welding or diffusion welding. Therefore, FIG. 19 shows an example of friction welding.

Dissimilar material joints 1 and 2 made of different metal materials and having the same diameter and different material properties are held in a state of being gripped by chucks 3 and 4 of a pressure welding device (FIG. 19 (a)). When one of the dissimilar material joints 1 is rotated, the joint surfaces that are in contact with each other due to friction are melted, and the dissimilar material joints 1 and 2 are joined by upsetting by the axial pressure P (FIG. 19B).
In such friction welding, the dissimilar joints 1 and 2 having the same diameter are joined to each other in the axial cross-section after joining, so that the amount and shape of burrs differ depending on the respective material strengths. The problem with this type of joint joining is that the joint has low impact strength and low reliability.

This tendency is not limited to friction welding, but may be any of cold welding, hot welding, diffusion welding, explosive welding, forging welding, ultrasonic welding, brazing, soldering, resistance welding, joining with an adhesive, and the like. There is also a problem in the joining structure between different kinds of metals by the method.

Therefore, for example, there is a friction welding method proposed in Japanese Patent Laid-Open No. 6-47570 as a conventional technique for improving the joining strength by applying it to joining members of different kinds of metals. In this friction welding method, the diameter of the member having the larger thermal expansion coefficient is made larger than that of the other member for joining, and the residual stress generated at the joining interface is relaxed to improve the joining strength.

According to Japanese Patent Laid-Open No. 4-143085, a copper material having a convex shape with a groove angle of 15 to 45 degrees is butted against an aluminum material and joined by electrical heating to improve the tensile strength. Further, in Japanese Patent Application Laid-Open No. 1-282166, in a bonded body of a metal member and a ceramic member, a ceramic forming angle formed by a part of a peripheral portion of a bonding interface of the ceramic member and a surface of the bonded body is 80 degrees or less, or 100 degrees. It is described that the thermal stress can be relaxed by setting the following.

Further, in Japanese Patent Laid-Open No. 1-282167, when joining members having different thermal expansion coefficients, a radius of curvature not less than a predetermined value is observed when the joining interface edge of the member having the smaller thermal expansion coefficient is viewed in the joining interface direction. It is disclosed that the thermal stress is relaxed by forming the curved surface.

[0008]

However, all of the conventional joining methods are intended for relaxation of residual stress, relaxation of thermal stress and improvement of tensile strength. It did not increase reliability.

Especially in the joining of different materials having different material properties, there is no problem in the static joint strength due to the optimization of the joining conditions, but in the joint strength as a whole, the joint strength is remarkably lowered with respect to the impact strength. It is clear that it is low.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and in joining dissimilar materials having different material properties, improve the impact strength of the joint and improve the reliability. It is to provide a joining method and a joining structure between the two.

[0011]

In order to achieve the above object, the invention according to claim 1 comprises a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy. In the method for joining dissimilar metal materials for coaxially joining the members, a joining surface formed of a concave surface on the end surface of the first member, and a joining surface formed of a convex surface corresponding to the concave surface on the end surface of the second member, respectively. It is formed in advance and the joint surfaces are butted to each other so that the first member and the second member
The member is held coaxially, and one of the first member and the second member is rotated while applying an axial pressure so that the edge of the joint surface of the second member and the free edge of the second member are rotated. It is characterized in that the joining is carried out by friction welding so that the angle formed by is within the range of 45 to 88 °.

According to the invention of claim 1, when the first member made of an aluminum material or an aluminum alloy and the second member made of titanium or a titanium alloy are joined by friction welding, the first member is formed. The concave joint surface of the end face of the and the second
When the joining surfaces of the convex surfaces of the end faces of the members are butted to each other and the joining is performed so that the angle between the edge portion of the joining surface of the second member and the free edge of the second member falls within the setting range of 45 to 88 °, The impact strength at the joint between the first member and the second member having different material properties can be significantly improved.

According to a second aspect of the present invention, there is provided a joining method for dissimilar metal materials in which a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined. A joint surface formed of a convex surface on the end surface of the first member, and a joint surface formed of a concave surface corresponding to the convex surface on the end surface of the second member are formed in advance, and the joint surfaces are abutted to each other, and The first member and the second member are coaxially held, and one of the first member and the second member is rotated while applying pressure in the axial direction, and the edge of the joint surface of the second member and the second member are rotated. It is characterized in that the joining is performed by friction welding so that the angle formed by the free edges of the members falls within the range of 120 to 178 °.

According to the invention of claim 2, contrary to the invention of claim 1, in the case where the end surface of the first member has a convex joint surface and the end surface of the second member has a concave joint surface, , The convex joint surface of the end surface of the first member and the concave joint surface of the end surface of the second member are butted against each other, and the angle formed by the edge portion of the joint surface of the second member and the free edge of the second member is 120. By joining by friction welding so as to fall within the set range of ˜178 °, the impact strength at the joint portion of the first member and the second member having different material properties is greatly improved as in the invention of claim 1. be able to.

According to a third aspect of the present invention, there is provided a method for joining dissimilar metal materials, which coaxially joins a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy. , The flat joining surfaces of the first member and the second member are butted against each other to hold the first member and the second member coaxially, and the first member and the second member while applying axial pressure. One of them is rotated, and the angle formed by the joint interface between the first member and the second member and the free edge of at least one of the first member and the second member is 90.
It is characterized in that the welding is performed by friction welding so that the temperature is less than °.

According to the invention of claim 3, unlike the inventions of claims 1 and 2, the end surface of the first member is a joint surface, and the end surfaces of the second members are flat joint surfaces. In the case of, the flat joint surfaces are butted against each other, and the second
When the members are joined by friction welding so that the angle formed by the edge of the joint surface of the member and the free edge of the second member falls within the set range of less than 90 °, the material is the same as the inventions of Claims 1 and 2. The impact strength at the joint between the first member and the second member having different characteristics can be significantly improved.

According to a fourth aspect of the present invention, there is provided a joining method for dissimilar metal materials in which a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined. , The first member and the second member are abutted against each other while pure aluminum is interposed between the joint surfaces of the first member and the second member, and the first member and the second member are coaxially held, and while applying axial pressure, One of the features is that one of the first member and the second member is rotated to perform joining by friction welding.

According to the invention of claim 4, between the joint surface of the first member made of aluminum or aluminum alloy and the joint surface of the second member made of titanium or titanium alloy, there is pure By joining by friction welding while interposing aluminum, the tensile strength at the joining portion of both members can be greatly improved.

According to a fifth aspect of the present invention, there is provided a joint structure for dissimilar metallic materials, in which a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined. The joining surface formed by the concave surface of the first member and the joining surface formed by the convex surface corresponding to the concave surface of the second member are joined by friction welding,
The angle between the edge of the joint surface of the member and the free edge of the second member is in the range of 45 to 88 °.

According to the fifth aspect of the invention, the joining surface is formed by the concave surface of the first member made of an aluminum material or an aluminum alloy, and the joining surface is formed by a convex surface of the second member made of titanium or a titanium alloy. The surface is joined by friction welding so that the angle between the edge of the joining surface of the second member and the free edge of the second member is within the setting range of 45 to 88 °. As a result, it is possible to obtain a joint structure in which the impact strength at the joint between the first member and the second member having different material properties is significantly improved.

According to a sixth aspect of the present invention, there is provided a joint structure for dissimilar metal materials in which a first member made of aluminum or aluminum alloy and a second member made of titanium or titanium alloy are coaxially joined. A joining surface made of a convex surface and a joining surface made of a concave surface corresponding to the convex surface of the second member are joined to the end surface of the first member by friction welding, and an edge portion of the joining surface of the second member and the second portion. The angle formed by the free edge of the member is in the range of 120 to 179 °.

According to the invention of claim 6, contrary to the invention of claim 5, the joining surface formed of the convex surface of the first member made of an aluminum material or an aluminum alloy and titanium or a titanium alloy is used as the material. When joining the concave joint surface of the second member by friction welding, the angle between the edge of the joint surface of the second member and the free edge of the second member is 12
By adopting a structure in which the bonding is performed within the setting range of 0 to 179 °, a bonding structure in which the impact strength at the bonding portion of the first member and the second member having different material characteristics is significantly improved is obtained. be able to.

According to a seventh aspect of the present invention, there is provided a joint structure for dissimilar metal materials in which a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined. When the flat joining surfaces of the first member and the second member are joined by friction welding, and the angle between the joining interface and the free edge of at least one of the first member and the second member is less than 90 °. Or the angle between the joining interface and the free edge of at least one of the first member and the second member is 90 °, and the angle between the other free edge is less than 90 °.

According to the invention of claim 7, the relationship between the joint surface of the first member made of an aluminum material or an aluminum alloy and the joint surface of the second member made of titanium or a titanium alloy is flat. In the case of a joining surface, the angle between the joining interface and the free edge of at least one of the first member and the second member is less than 90 °, or the joining interface and the first member or the second member. The members are joined so that the angle formed by at least one free edge of the members is 90 ° and the angle formed by the other free edge is less than 90 °, so that the members have different material properties. 1
It is possible to obtain a joint structure in which the impact strength at the joint between the member and the second member is significantly improved.

According to an eighth aspect of the present invention, there is provided a joint structure for dissimilar metal materials in which a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined. The joining surfaces of the first member and the second member are joined by friction welding, and pure aluminum is interposed between the joining surfaces.

According to the invention of claim 8, between the joint surface of the first member made of aluminum or an aluminum alloy and the joint surface of the second member made of titanium or a titanium alloy, a pure joint is formed. By adopting a structure in which aluminum is interposed and friction welding is performed, it is possible to obtain a joint structure in which the tensile strength at the joint portion of both members is significantly improved.

In the above-described joining method or joining structure according to any one of claims 1 to 8, the titanium or titanium alloy as the material of the second member is any one of α alloy, α-β alloy and β alloy, and preferably , Α alloy is Ti-0.3Mo-0.8
Ni, Ti-5Al-2.5Sn, Ti-5Al-2.5Sn-ELI, Ti-8A
l-Mo-V, Ti-6Al-2Sn-4Zr-Mo, Ti-6Al-2Nb
-Ta-0.8Mo, Ti-2.25Al-11Sn-5Zr-Mo, Ti-5A
l-5Sn-2Zr-2Mo, α-β alloy is Ti-6Al-4V, Ti
-6Al-4V-ELI, Ti-6Al-6V-2Sn, Ti-8Mn, Ti-7
Al-4Mo, Ti-6Al-2Sn-4Zr-6Mo, Ti-5Al-2Sn-2
Zr-4Mo-4Cr, Ti-6Al-2Sn-2 Zr-2Mo-2Cr, Ti-3
Al-2.5V, β alloy is Ti-10V-2Fe-3Al, Ti-13V-
11Cr-3Al, Ti-8Mo-8V-2Fe-3Al, Ti-13V-11.5
Mo-6Zr-4.5Sn.

Further, in the joining method or the joining structure according to claims 1 to 8, the thickness of the reaction layer of the intermetallic compound formed of aluminum or aluminum alloy and titanium or titanium alloy produced by friction welding is 20 μm or less. Is preferred. This is because the impact strength decreases when the thickness of the reaction layer of the intermetallic compound exceeds 20 μm.

In the fourth or eighth aspect, if the first member and the second member are ring-shaped members having the same inner and outer diameters, the thickness t of the pure aluminum is the first member. , (T / T) <0.5 with respect to the ring width T of the second member
Is preferred.

If the first member and the second member are ring-shaped,
For tensile strength, the ratio of the ring width T to the thickness t of pure aluminum is 0.
It has been found from the results of the tensile test that it gradually decreases until it reaches 5, and it hardly changes at 0.5 or less.
The thickness t of pure aluminum is larger than the ring width T as much as possible, so that the tensile strength is larger.

Further, in claim 4 or claim 8, if the first member and the second member are round bar-shaped members having the same diameter, the thickness t of the pure aluminum is equal to that of the round bar. It is preferable that (t / D) <0.5 with respect to the diameter D.

When the first member and the second member are round bar-shaped members, the tensile strength gradually decreases until the ratio of the diameter D of the round bar to the thickness t of pure aluminum reaches 0.5, and then becomes 0.5. It is known from the results of the tensile test that there is almost no change below, and it is set to the above range.

Further, if the first member and the second member are members having the same rectangular cross section, the length of the rectangular cross section in the vertical direction is a and the length in the horizontal direction is b, and the pure aluminum is used. Thickness t
Is (t / a) <0.5 (when a <b), or (t
It is preferable that /b)<0.5 (b <a).

If the first member and the second member are members having the same rectangular cross section, the tensile strength is as large as possible when the thickness t of pure aluminum is smaller than the smaller width of the member. Therefore, the above range is set.

Here, as a machine component to which the joint structure according to any one of claims 5 to 8 can be applied, a fastening portion fastened to another mechanical component is a member made of a titanium alloy, and the fastening is performed. Other than the parts, mechanical parts made of aluminum or aluminum alloy as a material, for example, constituent parts of a transmission mechanism can be mentioned. In this machine part, by adopting the joint structure according to any one of claims 5 to 8 for the joint portion between the titanium alloy and aluminum or aluminum alloy, the impact strength at the joint portion can be increased and sufficient reliability can be secured. At the same time, the material of the component can be replaced with expensive aluminum from inexpensive titanium alloy.

Further, as a machine part to which the joint structure according to any one of claims 5 to 8 can be applied, a titanium alloy is used as a portion where corrosion resistance is required, and aluminum or an aluminum alloy is used as a portion where corrosion resistance is not required. Machine parts,
For example, parts such as a rotating shaft of a stirring device used in a chemical plant can be mentioned. In this mechanical member, by using the joint structure according to any one of claims 5 to 8 for the joint portion between the titanium alloy and aluminum or aluminum alloy, only the portion where corrosion resistance is required is made of titanium alloy. Thus, it is possible to secure the corrosion resistance and at the same time replace the material of the part where the corrosion resistance is not required with a lightweight and inexpensive aluminum.

Further, as the mechanical parts to which the joint structure according to any one of claims 5 to 8 can be applied, there can be mentioned a peripheral part of a contact used in a power breaker. In this mechanical part, a member made of a titanium alloy is used for a portion where heat resistance is required, and a member made of aluminum is used for a portion where heat resistance is not required, and these members are joined together. By adopting the joining structure according to any one of 8 above, a titanium alloy can be used for a portion directly exposed to a high temperature arc, and an aluminum material can be used for other portions, and a heat resistant coating is applied to the aluminum material. You can eliminate the need.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a joining method and a joining structure between metallic dissimilar materials according to the present invention will be described in detail below with reference to the accompanying drawings. First Embodiment FIG. 1 is a diagram showing a method for joining metallic dissimilar materials according to a first embodiment of the present invention. Reference numeral 10 is a first member made of pure aluminum (hereinafter referred to as an aluminum material).
Here, 12 is a second member made of a titanium alloy, for example, an α-β titanium alloy (hereinafter referred to as a titanium alloy material). In this embodiment, both the aluminum material 10 and the titanium alloy material 12 are round bars having the same diameter.

In FIG. 1A, a concave surface 11 to be a joint surface is formed in advance on the end surface of the aluminum material 10, and the concave surface 1 corresponding to the convex surface 11 is also formed on the end surface of the titanium alloy material 12.
A joint surface composed of 3 is formed in advance. In this example, both the concave surface 11 and the convex surface 13 are curved surfaces that are smoothly curved with a predetermined curvature.

The aluminum material 10 and the titanium alloy material 12 are coaxially held in a state of being gripped by the chucks 3 and 4 of the pressure welding device. Then, as shown in FIG. 1B, when one aluminum material 10 is rotated, the titanium alloy material 10 is abutted against the titanium alloy material 10 and upset pressure is applied by a pressing force P in the axial direction. Melts, aluminum material 10
And the titanium alloy material 12 are integrally joined.

FIG. 2A shows a cross section of the joint between the aluminum material 10 and the titanium alloy material 12. As shown in FIG. 2A, at the joining interface between the aluminum material 10 and the titanium alloy material 12, the edge portion 14 of the joining surface of the concave curved surface is made of titanium based on the joining surface of the titanium alloy material 12. The joining structure is such that the free edge 15 of the alloy material 12 forms an acute angle θ1 within a certain range. This angle θ1 is preferably within the angle setting range of 45 to 88 °.

Next, FIG. 2B shows that the titanium alloy material 12 is formed at the joint interface between the aluminum material 10 and the titanium alloy material 12.
An example of the joining structure in which the edge portion 14 of the joining surface forms an obtuse angle θ2 within a predetermined range with the free edge 15 of the titanium alloy material 12 will be shown. The angle θ2 in this case is preferably within the angle setting range of 120 to 179 °. Thus, the angle θ2 formed by the edge 14 and the free edge 15 of the joining surface of the titanium alloy material 12 is
2 is set to an obtuse angle, contrary to the joining structure of FIG.
2 has a convex surface formed in advance. The method of friction welding is the same as that shown in FIG.

As shown in FIGS. 2 (c) and 2 (d), unlike the case of FIGS. 2 (a) and 2 (b), an aluminum material 10 having a flat end surface with a convex convex surface forming a joint surface, Even in the case of friction welding with the titanium alloy material 12 having a concave surface corresponding to the convex surface as a bonding surface, a similar bonding structure can be obtained. Figure 2
In the case of (c), the angle θ1 formed by the edge portion 14 of the joining surface of the titanium alloy material 12 and the free edge 15 of the titanium alloy material 12 is 45 to 8.
FIG. 2D shows a joining structure in the range of 8 °, in which the angle θ2 formed by the edge portion 14 of the joining surface of the titanium alloy material 12 and the free edge 15 of the titanium alloy material 12 is in the range of 120 to 179 °. It is a structure.

The edge 14 of the joining surface of the titanium alloy material 12 that makes an angle within the above range with the free edge 15 is formed in a range of 5% or more with respect to the diameter D of the titanium alloy material 12. If there is no problem.

Next, FIG. 3 shows that the angle θ between the edge of the joining surface of the titanium alloy material and the free edge is 180 ° at intervals of 5 ° from 30 °.
It is a figure which shows the result of having produced the test piece which changed to ° and performing the tensile test about the test piece. FIG. 4 is a diagram showing a result of an impact test performed on the same test piece.

As shown in FIG. 3, the tensile strength showed a constant value regardless of the angle θ between the edge of the joining surface of the titanium alloy material and the free edge, but the impact strength is shown in FIG. As shown in the figure, the angle θ is 120 ° between 45 ° and 88 °.
A high impact strength value was shown in the range from to 179 °. Incidentally, in the conventional joining structure of FIG. 19, θ is 90 in FIG.
This is equivalent to the case of °, and it is possible to greatly improve the impact strength of the aluminum-titanium alloy joint by setting the angle between the edge of the joint surface and the free edge within the above range of angles. Become.

The above is the embodiment in which the present invention is applied to the joining between different rod-shaped metallic dissimilar materials. Next, the embodiment in which the present invention is applied to the joining between tubular metallic dissimilar materials will be described. This will be described with reference to FIG.

In FIG. 5, 20 is a tubular aluminum material made of aluminum, and 22 is a tubular titanium alloy material made of titanium alloy. The aluminum material 20 and the titanium alloy material 22 have the same inner diameter and outer diameter.

FIG. 5A shows the outer peripheral edge portion 14a of the concave joint surface of the titanium alloy material 22 as a reference at the joint interface between the aluminum material 20 and the titanium alloy material 22.
The inner peripheral edge portion 14b and the inner peripheral edge portion 14b have a joining structure in which the free edge 15a of the outer peripheral portion and the free edge 15b of the inner peripheral portion of the titanium alloy material 22 form an acute angle θ1 within a certain range. By setting this angle θ1 within the angle setting range of 45 to 88 ° similarly to the joint structure of FIGS. 2A and 2C, the impact strength can be significantly improved.

In order to frictionally weld such a tubular aluminum material 20 and titanium alloy material 22 to each other, the end surface of the aluminum material 20 corresponds to a convex surface to be a joint surface, and the end surface of the titanium alloy material 12 corresponds to a convex surface. The concave surface is formed in advance as in the case of FIG. Such an uneven surface may be a curved surface that smoothly curves with a predetermined curvature.

FIG. 5B shows the relationship between the unevenness of the joint surface.
The reverse of (a), in this case titanium alloy 2
The outer peripheral edge portion 14a and the inner peripheral edge portion 14b of the joint surface of 0 respectively form the free edge 15a of the outer peripheral portion and the free edge 15b of the inner peripheral portion of the titanium alloy material 22, and θ2 is set within the range of 120 to 179 °. Has been done. Next, as shown in FIG.
Unlike the embodiments described so far, a joining structure is shown in which the aluminum material 10 and the titanium alloy material 12 are joined together with their respective flat joining surfaces. 6 (a) and 6 (b)
As shown in FIG. 3, in this joint structure, the aluminum material 10 and the titanium alloy 12 are members having the same diameter, and the joint interface 16 between them is
And the free edge 17a of the aluminum material 10 and the free edge 17b of the titanium alloy material 12 are both joined by friction welding so that the angle .theta.1 is less than 90 degrees. In the case of this joint structure, as shown in FIG. 6A, the free edge 17a of the aluminum material 10 that makes an angle of less than 90 ° with the joint interface 16,
The free edges 17b of the titanium alloy material 12 may each be inclined straightly, or may be a curved surface as shown in FIG. 6 (b).

FIGS. 6C and 6D show that
The joining interface 16 between the aluminum material 10 and the titanium alloy material 12 and the free edge 17a of the aluminum material 10 form a right angle, whereas the joining interface 16 and the free edge 17b of the titanium alloy material 12 form a right angle.
The angle θ1 formed by is less than 90 °. In this case, the aluminum material 10 has a larger joint diameter than the titanium alloy material 12, and the titanium alloy material 12 has a larger diameter than the aluminum material 10. The angle between the free edge 17b and the bonding interface 16 is a right angle, and the angle between the aluminum material 10, the free edge 17a and the bonding interface 16 is less than 90 °.

Even with the joint structure as shown in FIGS. 6 (a) to 6 (d), the impact strength can be significantly improved as compared with the conventional joint structure as shown in the figure. .

FIG. 7 shows a joint structure in which the joint structure of FIG. 6 is applied to a tubular aluminum material 10 and a titanium alloy material 12. Even if the members to be joined are tubular, FIG.
The impact strength can be improved by joining in the same manner as in the above.

Next, FIG. 8 shows the reaction layer thickness and impact strength of the intermetallic compound generated at the joining interface between the aluminum material and the titanium alloy material by friction welding in the embodiment described with reference to FIGS. It is a graph which shows a relationship.

As can be understood from FIG. 8, when the reaction layer thickness of the intermetallic compound exceeds 20 μm, the impact strength decreases. Therefore, regarding friction welding, the reliability of the bonded joint can be secured by setting the thickness of the reaction layer of the intermetallic compound to 20 μm or less.

Further, in the joining structure of the aluminum material and the titanium alloy according to the present embodiment, if the electrical resistance of the joining portion is high, the joining portion is heated during energization, and the reaction layer of the intermetallic compound at the joining interface grows to 20 μm. Since the impact strength decreases beyond that, it is desirable that the electrical resistance of the joint be equal to that of the base material.

If the impact strength of the joint is less than or equal to the base material, fracture may occur at the joint, so the impact strength of the joint is preferably the same as that of the base material.

Further, after joining the aluminum material and the titanium alloy, heat treatment may be applied to the joint to increase the hardness of the joint to the hardness of the base material.

Second Embodiment Next, FIG. 9, FIG. 11 and FIG.
FIG. 8 is a diagram showing a bonding structure between different kinds of metals according to the second embodiment of the present invention. In this second embodiment, the aluminum material 1
0 and the titanium alloy material 12 are abutted against each other with pure aluminum 20 interposed therebetween and held coaxially with each other, and one of the first member and the second member is applied while applying axial pressure. It is an embodiment common to the point that it has a joining structure in which is rotated and joined by friction welding.

FIG. 9 shows an aluminum material 10 and a titanium alloy material 12
Both of them show a joining structure of annular members having the same inner and outer diameters. Regarding the pure aluminum 20 interposed between the joint surface of the aluminum material 10 and the joint surface of the titanium alloy material 12, the ratio of the thickness t to the ring width T of the aluminum material 10 has the following relationship with the tensile strength. Is known.

FIG. 10 shows pure aluminum 2 with respect to the ring width T.
The result of having carried out the tensile test about the sample which changed the thickness of 0 is shown. As can be seen from FIG. 10, the tensile strength gradually decreases until the ratio of the ring width T and the thickness t of the pure aluminum 20 reaches 0.5, and hardly changes below 0.5. Therefore, the thickness t of the pure aluminum 20 is larger when the thickness t is smaller than the ring width as much as possible, and the upper limit of the thickness is within the range of (t / T) <0.5. desirable.

FIG. 11 shows an aluminum material 10 and a titanium alloy material 1.
Both of the two show a joint structure of round bar-shaped members having the same diameter. With respect to the pure aluminum 20 interposed between the joint surface of the aluminum material 10 and the joint surface of the titanium alloy material 12, when the ratio of the thickness t to the diameter D of the round bar changes, the tensile strength is changed as shown in FIG. It is known to change.

As can be seen from FIG. 12, the tensile strength gradually decreases until the ratio of the thickness t of the pure aluminum 20 to the diameter D of the round bar reaches 0.5, and hardly changes below 0.5. Therefore, as for the thickness t of the pure aluminum 20, the thinner the diameter D of the round bar as much as possible, the larger the tensile strength is, and the upper limit of the thickness is within the range of (t / D) <0.5. Is desirable.

Next, FIG. 13 shows a joining structure of members each having a rectangular cross section with a vertical width a and a horizontal width b for both the aluminum material 10 and the titanium alloy material 12. As for the pure aluminum 20 interposed between the joint surface of the aluminum material 10 and the joint surface of the titanium alloy material 12, when the ratio of the thickness t and the width a or b, whichever is smaller, changes, as shown in FIG. It has been found that the tensile strength changes.

As can be seen from FIG. 14, the tensile strength is until the ratio of the thickness t of the pure aluminum 20 to the smaller width of the member (here, the width a in the vertical direction) becomes 0.5. It gradually decreases, and hardly changes at 0.5 or less. Therefore, as for the thickness t of the pure aluminum 20, the thinner the width of the member is, the thinner the tensile strength is, and the upper limit of the thickness is within the range of (t / a) <0.5. Is desirable (if the width b in the horizontal direction is smaller, (t /
b) <0.5).

In the embodiments shown in FIGS. 9, 11, and 13, the pure aluminum 20 interposed on the joint surface is a plate-like member having the above-mentioned thickness and is sandwiched between both joint surfaces when friction-welding. Alternatively, the aluminum material 10 or the titanium alloy material 12 may be preliminarily overlaid with pure aluminum to the end face of either one of the aluminum material 10 and the titanium alloy material 12 and then friction-welded. As a method of overlaying pure aluminum in advance,
Friction welding, cold welding, hot welding, diffusion welding, explosion welding,
Forge welding, ultrasonic bonding, brazing, soldering, resistance welding,
The same effect can be obtained by using any method such as molten metal injection, casting, and adhesive bonding.

The first and second embodiments of the present invention have been described above by taking the joining of the pure aluminum material and the titanium alloy as an example. However, the aluminum alloy is used instead of the pure aluminum material, and the titanium alloy is used. As a matter of course, in addition to the α-β alloy, pure titanium, α alloy, and β alloy can be used to join the dissimilar metal materials by combining them.

Here, as the α alloy, Ti-0.3Mo-0.
8Ni, Ti-5Al-2.5Sn, Ti-5Al-2.5Sn-ELI, Ti-8
Al-Mo-V, Ti-6Al-2Sn-4Zr-Mo, Ti-6Al-2
Nb-Ta-0.8Mo, Ti-2.25Al-11Sn-5Zr-Mo, Ti-
5Al-5Sn-2Zr-2Mo and the like.

As the α-β alloy, Ti-6Al-4V, Ti-
6Al-4V-ELI, Ti-6Al-6V-2Sn, Ti-8Mn, Ti-7A
l-4Mo, Ti-6Al-2Sn-4Z r-6Mo, Ti-5Al-2Sn-2Z
r-4Mo-4Cr, Ti-6Al-2Sn-2Zr-2Mo-2Cr, Ti-3A
There are l-2.5V etc.

For the β alloy, Ti-10V-2Fe-3Al, Ti-13
V-11Cr-3Al, Ti-8Mo-8V-2Fe-3Al, Ti-13V-1
There are 1.5Mo-6Zr-4.5Sn, etc.

Third Embodiment FIGS. 15 to 18 are views showing an example of a mechanical component having a joint structure of a member made of an aluminum material and a member made of a titanium alloy to which the present invention is applied.

FIG. 15 shows components constituting a power transmission mechanism for transmitting the rotation from the power unit to another mechanism in a wide range of industrial machines.

In FIG. 15, for example, 30 is a fastening portion connected to the drive side mechanism, and 31 is a fastening portion connected to the driven side mechanism. The driving-side fastening portion 30 and the driven-side fastening portion 31 are connected by two transmission rods 32. The fastening portions 30 and 31 are made of titanium alloy, and the transmission rod 32 is made of aluminum. Fastening part 30,
31 includes a joint portion 30 for joining with the transmission rod 32.
a and 31a are integrally formed. For joining the joint portions 30a and 31a of the fastening portions 30 and 31 and the transmission rod 32, the joining structure by the friction welding described with reference to FIG. 2B or 2D described above is adopted. The joint structure is such that the edges of the convex curved joint surfaces of the joint portions 30a and 31a made of titanium alloy and the free edges of the joint portions 30a and 30b form an angle of 120 to 179 °. There is. In this case, by making the joint surfaces of the joint portions 30a and 31a concave, the angle formed by the edge of the joint surface with the free edge of the joint portions 30a and 30b as shown in FIG. 2A or 2C. May be in the range of 45 to 88 °.

The conventional joining structure by friction welding of aluminum and titanium alloy cannot be used for the joint portion of this kind of transmission component because of its low impact strength and low reliability, but the joining structure according to the present invention is sufficient. Since it is possible to obtain a high impact strength, the present invention can be applied to a joint portion of a transmission component that requires an impact strength, thereby increasing the impact strength at the joint portion between the joint portions 30a and 31b and the transmission rod. Sufficient reliability can be ensured, and the cost of the component shown in FIG. 15 can be reduced by replacing the expensive titanium alloy with inexpensive aluminum as the material of the component.

FIG. 16 shows an example in which the joining structure of the present invention is applied to the rotating shaft of a mixing, dispersing and stirring apparatus for raw materials used in a chemical plant or the like. In FIG. 16, a blade 33 is provided at the tip of the rotary shaft, and the blade mixes and stirs the raw materials. The rotating shaft is composed of a first shaft portion 34 that comes into direct contact with the raw material and a partial second shaft portion 35 that rarely comes into contact with the raw material, and the first shaft portion 34 is made of a titanium alloy having strong corrosion resistance. The biaxial portion 35 is made of aluminum. Then, the joining structure by the friction welding described in FIG. 2 (b) or FIG. 2 (d) is adopted for joining the first shaft portion 34 and the second shaft portion 35, and the first shaft made of titanium alloy is used. The joining structure is such that the edge of the convex curved joining surface of the portion 34 forms an angle with the free edge of the first shaft portion 34 within the range of 120 to 179 °. In this case, by making the joint surface of the first shaft portion 34 a concave surface, the edge of the joint surface forms an angle of 45 with the free edge of the shaft portion 34 as shown in FIG. 2A or 2C. A junction structure having a range of up to 88 ° may be used.

The conventional joining structure by friction welding of aluminum and titanium alloy cannot be used for the rotating shaft of this kind of stirring equipment because of its low impact strength and low reliability, but the joining structure according to the present invention is sufficient. It can be applied to join the rotating shafts of agitating equipment because of its high impact strength. Titanium alloy is used only for the parts where corrosion resistance is required, and at the same time, the rotating shaft is made of lightweight and inexpensive aluminum. It is possible to achieve cost reduction of about 30% as a whole.

Next, FIG. 17 shows parts constituting a power transmission mechanism for transmitting power from a drive unit used in a power breaker to another mechanism.

In FIG. 17, for example, 36 is a fastening portion connected to the drive side mechanism, and 37 is a fastening portion connected to the driven side mechanism. The driving-side fastening portion 36 and the driven-side fastening portion 37 are connected by two transmission rods 38. The fastening portions 36 and 37 are made of titanium alloy, and the transmission rod 38 is made of aluminum. Fastening portion 36,
37 includes a joint portion 36 for joining with the transmission rod 38.
a and 37a are integrally formed, and the joint portions 36a and 37a
The joining structure of the present invention is applied to the joining of a and the transmission rod 38. The joint structure itself is the same as that in FIG. 15, and the detailed description thereof will be omitted.

The joint portion 30a of the transmission mechanism component,
By applying the present invention to the joint portion between 31b and the transmission rod, it is possible to increase the impact strength and ensure sufficient reliability, and replace the expensive titanium alloy with inexpensive aluminum as the material of the component, and It becomes possible to realize cost reduction.

FIG. 18 shows an example in which the joint structure according to the present invention is applied to the contactor peripheral parts used in a power circuit breaker.

The peripheral parts of the contact, which are opened and closed by this kind of contact, are directly exposed to a high-temperature arc, so that it is necessary to apply a heat-resistant coating to the aluminum material, and there is a problem that the cost becomes high. Therefore, the member 39 that is directly exposed to the arc
Titanium alloy is used for the material, and aluminum is used for the other members 40 that are not exposed to the arc.
The present invention was applied to the joining with 0. That is, the joining structure is such that the angle of the edge of the joining surface of the portion 39 with the free edge of the member 39 is within the range of 120 to 179 ° by friction welding. As a result, it has become possible to achieve a significant reduction in the weight of the parts around the contact and a reduction in cost.

[0083]

As is apparent from the above description, according to the present invention, it is possible to enhance the impact strength of the joint portion and enhance the reliability in joining dissimilar materials having different material properties such as aluminum and titanium alloy. Becomes

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a joining method according to an embodiment of the present invention.

FIG. 2 is a view showing a cross section of a joint portion of the joint structure according to the first embodiment of the present invention.

FIG. 3 is a diagram showing the results of a tensile test on a sample having the bonded structure of FIG.

FIG. 4 is a view showing a result of an impact test on a sample having the joint structure of FIG.

FIG. 5 is a view showing a cross section of a joint portion of an embodiment in which the present invention is applied to join tubular members together.

FIG. 6 is a view showing a cross section of a joint portion of another joint structure according to the present invention.

7 is a view showing a cross section of a joint portion of an embodiment in which the joint structure of FIG. 6 is applied to tubular members.

FIG. 8 is a diagram showing the relationship between the thickness of the intermetallic compound at the joint interface and the impact strength.

FIG. 9 is a diagram showing a joining structure according to a second embodiment of the present invention.

10 is a diagram showing a relationship between (thickness t / ring width T) and tensile strength of pure aluminum interposed in a joint surface in the joint structure of FIG.

FIG. 11 is a view showing an example in which the joining structure according to the second embodiment of the present invention is applied to joining round bars.

FIG. 12 is a diagram showing a relationship between (thickness t / diameter D of round bar) of pure aluminum and tensile strength interposed in the joint surface in the joint structure of FIG. 11.

FIG. 13 is a view showing an example in which the joining structure according to the second embodiment of the present invention is applied to joining members having rectangular cross sections.

14 is a diagram showing a relationship between (thickness t / width of member) and tensile strength of pure aluminum interposed in the joint surface in the joint structure of FIG.

FIG. 15 is a diagram showing a power transmission mechanism component having the joining structure of the present invention.

FIG. 16 is a view showing a rotating shaft of a stirring device having a joint structure of the present invention.

FIG. 17 is a diagram showing a transmission mechanism component of a power breaker having a joint structure of the present invention.

FIG. 18 is a view showing components around a contactor of a power breaker having a joint structure of the present invention.

FIG. 19 is a schematic explanatory view of conventional friction welding.

[Explanation of symbols]

10 Aluminum material (first member) 12 Titanium alloy material (second member) 14 Edge of joint surface 15 Free edge

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuyoshi Udagawa             2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Hamakawasaki Factory (72) Inventor Akiko Suyama             2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa             Ceremony Company Toshiba Hamakawasaki Factory (72) Inventor Yoshiyasu Ito             2-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa               Toshiba Keihin Office F-term (reference) 4E067 AA05 AA12 AA26 AB03 AD03                       BG00 DA13 EA08 EB00 EC05                       EC06

Claims (8)

[Claims] 1. A method for joining between dissimilar metallic materials, wherein a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined together. The end surface has a concave joining surface,
Joining surfaces made of convex surfaces corresponding to the concave surfaces are formed in advance on the end surfaces of the members, and the joining surfaces are butted to hold the first member and the second member coaxially, and the axial pressing force is applied. While rotating one of the first member and the second member while adding the angle, the angle between the edge of the joint surface of the second member and the free edge of the second member is within the range of 45 to 88 °. A method for joining dissimilar metal materials, characterized in that the joining is performed by friction welding as described above. 2. A method for joining between dissimilar metallic materials for coaxially joining a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy, comprising: The joining surface formed of a convex surface on the end surface is referred to as the second
Joining surfaces, which are concave surfaces corresponding to the convex surfaces, are formed in advance on the end surfaces of the members, and the joining surfaces are butted to hold the first member and the second member coaxially, and the axial pressing force is applied. While one of the first member and the second member is rotated while adding, the angle between the edge of the joint surface of the second member and the free edge of the second member is within the range of 120 to 178 °. A method for joining dissimilar metal materials, wherein the joining is performed by friction welding as described above. 3. A method for joining between dissimilar metallic materials, wherein a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined together. The flat joining surfaces of the second member are butted against each other to hold the first member and the second member coaxially, and one of the first member and the second member is rotated while applying axial pressure. And, the joining by friction welding is performed so that an angle formed by a joining interface between the first member and the second member and a free edge of at least one of the first member and the second member is less than 90 °. Method for joining dissimilar metal materials. 4. A joining method between metallic dissimilar materials which coaxially joins a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy, wherein: The first member and the second member are held coaxially by abutting against each other with pure aluminum interposed between the joining surfaces of the second member, and the first member and the second member are pressed while applying axial pressure. A method for joining dissimilar metal materials, characterized in that one of the members is rotated to perform joining by friction welding. 5. A joint structure between metallic dissimilar materials in which a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined. A joining surface made of a concave surface and a joining surface made of a convex surface corresponding to the concave surface of the second member are joined by friction welding to form an edge portion of the joining surface of the second member and a free edge of the second member. A joint structure between dissimilar metal materials, wherein the angle is in the range of 45 to 88 °. 6. A joint structure between dissimilar metal materials in which a first member made of aluminum or an aluminum alloy and a second member made of titanium or a titanium alloy are coaxially joined to each other. A joining surface made of a convex surface and a joining surface made of a concave surface corresponding to the convex surface of the second member are joined to each other by friction welding, and an edge portion of the joining surface of the second member and a free edge of the second member are joined. A joint structure between different kinds of metal, wherein the angle formed is in the range of 120 to 179 °. 7. A joint structure between dissimilar metallic materials in which a first member made of aluminum or an aluminum alloy is coaxially joined to a second member made of titanium or a titanium alloy, and the first member is The flat joint surfaces of the second member are joined by friction welding, and the angle between the joint interface and the free edge of at least one of the first member and the second member is 90.
Or less than 90 °, or an angle between the joining interface and a free edge of at least one of the first member and the second member is 90 °, and an angle between the other free edge is less than 90 °. Metal joint structure between dissimilar materials. 8. A joint structure between metallic dissimilar materials in which a first member made of aluminum or an aluminum alloy is coaxially joined to a second member made of titanium or a titanium alloy, and the first member is A joining structure between dissimilar metal materials, wherein joining surfaces of the second member are joined together by friction welding, and pure aluminum is interposed between the joining surfaces.