JP2022127105A - Joining method of heterogeneous metal - Google Patents

Abstract

To achieve excellent joining by using frictional agitation while superposing two metal members mutually differing in kind.SOLUTION: A first metal layer 10 and a second metal member 20 differing in kind are prepared, the first metal member 10 and the second metal member 20 are superposed, and processing for pressing against an axially rotating rotary tool 30 from the side of the first metal member 10 is performed, and among a boundary surface 3 of the first metal member 10 and the second metal member 20, when joining a processing area 5 by the rotary tool 30, a third metal layer 40 for promoting joining of the first metal member 10 and the second metal member 20 is included in a part along a contour of a processing planning area 5A for planning processing by the rotary tool 30, and the third metal layer 40 is not included at a part inside the part along the contour.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method for joining dissimilar metals, in which two metal members of different types are superimposed and joined by friction stir.

Friction stir welding is one of the techniques for joining members. A cylindrical rotary tool is used, and the members are joined by pressing against the joining portion while rotating the rotary tool. The members are softened by frictional heat generated when the rotating tool is pressed, and the rotating force of the rotating tool causes plastic flow around the joint, thereby integrating the plurality of members.

For example, the applicant recognizes Patent Document 1 below as a prior art document in which two metal plates are superimposed and joined by friction stir welding.

JP-A-2005-28378

The aforementioned Patent Document 1 relates to a friction stir welding method for a lap joint, and has the following description.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to enable lap welding of metals having different melting points by friction stir welding.
[0006]
[Means to solve the problem]
In the lap welding of a plurality of members, the present invention presses a welding tool only toward the upper plate side, stirs only the vicinity of the surface of the upper plate by frictional heat, and raises the temperature of the overlapping surfaces by the frictional heat. It is to join by diffusion reaction between the members to be joined.
[0008]
In the method of lap-joining by press-fitting a welding tool only to one member side, a pressing force is applied to the lapped surfaces by friction stir, and the lapped surfaces are brought into close contact with each other. Furthermore, due to frictional heat, a reaction layer is formed by a diffusion reaction between the metal of the upper plate and the metal of the lower plate on the overlapping surfaces. Thereby, the upper plate and the lower plate are joined. According to this method, it is also possible to join dissimilar metals. Also, in the joining of similar materials, a reaction layer is not formed on the joining surface, and the joining is performed by mutual diffusion between the members.
[0011]
By plating the overlapping surfaces of the joining member with a soft metal, the overlapping surfaces can be more easily brought into close contact with each other. Therefore, a reaction layer is easily formed. Nickel, zinc, copper, tin, etc. are particularly effective as soft metals.

The above Patent Document 1 discloses that when a plurality of metals having different melting points are superimposed and joined by friction stir, the overlapping surfaces of joining members are plated with a soft metal.
However, in the technique of Patent Document 1, the entire joined region is in a state where the metal on the upper plate side and the metal on the lower plate side are mixed with the plated soft metal. In other words, a third component is present, which is not preferable depending on the required properties.
On the other hand, if the soft metal is not plated, the bonding state of the contour portion of the region where the bonding tool is pressed becomes unstable, reducing reliability.

The present invention has been made with the following objects in order to solve the above problems.
To provide a method for joining dissimilar metals capable of superimposing two metal members of different types and joining them well by utilizing friction stir.

In order to achieve the above object, the method for joining dissimilar metals according to claim 1 employs the following configuration.
preparing a first metal member and a second metal member of different types,
Overlapping the first metal member and the second metal member,
By pressing an axially rotating rotary tool from the side of the first metal member, a region of the boundary surface between the first metal member and the second metal member to be processed by the rotary tool is joined. When doing
The first metal member and the second metal member are formed on the boundary surface between the first metal member and the second metal member along the contour of the planned processing area scheduled to be processed by the rotary tool. A third metal layer is interposed for promoting the bonding of the metal members, and the third metal layer is not interposed inside the portion along the contour.

In addition to the configuration described in claim 1, the method for joining dissimilar metals according to claim 2 employs the following configuration.
The first metal member against which the rotary tool is pressed is made of a metal having a hardness lower than that of the second metal member.

The dissimilar metal joining method described in claim 3 employs the following configuration in addition to the configuration described in claim 2.
The metal forming the third metal layer is lower in hardness than the second metal member and higher in hardness than the first metal member.

The method for joining dissimilar metals according to claim 4 employs the following configuration in addition to the configuration described in claim 1.
The first metal member against which the rotary tool is pressed is made of a metal having a lower melting point than the second metal member.

The dissimilar metal joining method described in claim 5 employs the following configuration in addition to the configuration described in claim 4.
The metal forming the third metal layer has a lower melting point than the second metal member and a higher melting point than the first metal member.

In the method of joining dissimilar metals according to claim 1, a first metal member and a second metal member of different types are prepared, and first, the first metal member and the second metal member are stacked. Then, a rotary tool that rotates about its axis is pressed from the side of the first metal member to join the machining region of the boundary surface between the first metal member and the second metal member by the rotary tool. do.
At this time, of the boundary surface between the first metal member and the second metal member, the first metal member and the A third metal layer is interposed to promote bonding of the second metal member. Furthermore, the third metal layer is not interposed inside the portion along the contour.
By doing so, the bonding state of the contour portion of the processing region is improved and the reliability is improved, while the third component does not exist in the portion inside the contour of the processing region, and the desired characteristics can be obtained. . Two metal members of different types can be superimposed on each other and joined well by using friction stir.

In the method for joining dissimilar metals according to claim 2, the first metal member against which the rotary tool is pressed is made of a metal having a hardness lower than that of the second metal member.
Since the rotary tool is pressed against only the first metal member having a low viscosity during plastic flow, adhesion of metal to the rotary tool is suppressed, and the frequency of maintenance of the rotary tool can be reduced. In addition, since the energy required to generate plastic flow is small, it is advantageous in saving power.

In the method of joining dissimilar metals according to claim 3, the metal forming the third metal layer is lower in hardness than the second metal member and higher in hardness than the first metal member.
By doing so, the bonding state of the contour portion of the processing area is improved to improve the reliability.

In the method for joining dissimilar metals according to claim 4, the first metal member against which the rotary tool is pressed is made of a metal having a melting point lower than that of the second metal member.
If the first metal member against which the rotary tool is pressed has a higher melting point, the second metal member, which is the mating member, begins to melt when the temperature of the first metal member reaches a point where the first metal member plastically flows, resulting in defective joining. or defects may occur. By using a metal having a melting point lower than that of the second metal member for the first metal member against which the rotary tool is pressed, it is possible to prevent the occurrence of the above inconveniences.

In the method of joining dissimilar metals according to claim 5, the metal forming the third metal layer has a melting point lower than that of the second metal member and higher than that of the first metal member.
By doing so, the bonding state of the contour portion of the processing area is improved to improve the reliability.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining embodiment of the joining method of dissimilar metals of this invention. It is a figure explaining a 3rd metal layer.

Next, a mode for carrying out the present invention will be described.

[Basic process]
FIG. 1 is a diagram illustrating an embodiment of a method for joining dissimilar metals according to the present invention.

In the present invention, the first metal member 10 and the second metal member 20 of different types are prepared. The first metal member 10 and the second metal member 20 are different kinds of metals. The first metal member 10 and the second metal member 20 may be pure metals or alloys. It is preferable to form the first metal member 10 in a plate shape. In the illustrated example, both the first metal member 10 and the second metal member 20 are rectangular plates, and the thickness of the first metal member 10 is set thinner than that of the second metal member 10. there is The second metal member 20 is not limited to a plate shape, and may be block-shaped or the like. In the figure, reference numeral 1 is an anvil.

The first metal member 10 is overlaid on the second metal member 20 . In this state, processing is performed by pressing the rotary tool 30 that rotates about its axis from the side of the first metal member 10 . In this example, pressure is applied perpendicularly to the surface of the first metal member 10 by the end of the rotary tool 30, and in this state, the rotary tool 30 is pressed against the surface of the first metal member 10. to move it in parallel. As a result, of the interface 3 between the first metal member 10 and the second metal member 20, the machining region 5 by the rotary tool 30 is joined.

In the illustrated example, the machining area 5 is a trajectory along which the tip of the rotary tool 30 moves, and is a belt-like area. In the working region 5, plastic flow occurs in the first metal member 10, and the boundary 3 between the first metal member 10 and the second metal member 20 is joined by friction stir welding. Alternatively, the boundary surfaces 3 of the first metal member 10 and the second metal member 20 are joined by solid phase diffusion.

The rotating tool 10 can be penetrated from the surface of the first metal member 10 in the thickness direction. At this time, the penetration depth is up to the thickness dimension of the first metal member 10 .

[Third metal layer 40]
FIG. 2 is a diagram for explaining the third metal layer 40. As shown in FIG.
In the present invention, the third metal layer 40 is interposed between the first metal member 10 and the second metal member 20 in the basic steps described above. The third metal layer 40 is for promoting bonding between the first metal member 10 and the second metal member 20 .

The third metal layer 40 is formed along the contour of the planned processing area 5A, which is scheduled to be processed by the rotary tool 30, in the interface 3 between the first metal member 10 and the second metal member 20. intervene in the part In the illustrated example, the planned machining area 5A is an area scheduled to become the machining area 5 by the above-described process, and the tip of the rotary tool 30 is positioned against the surface of the first metal member 10. It is a belt-shaped area that becomes the trajectory of movement.

Further, in the present invention, the third metal layer 40 is not interposed inside the portion along the contour. Therefore, in the region where the third metal layer 40 is not interposed inside the portion along the outline, the boundary surface 3 between the first metal member 10 and the second metal member 20 is the same as that of the first metal member. 10 and the second metal member 20 are directly joined.

〔Metal material〕
It is preferable that the first metal member 10 against which the rotary tool 30 is pressed is made of a metal having a hardness lower than that of the second metal member 20 . By doing so, since the rotary tool 30 is inserted only into the first metal member 10 having a low viscosity during plastic flow, adhesion of metal to the rotary tool 30 is suppressed. Also, less energy is required to cause plastic flow.

It is preferable that the metal constituting the third metal layer has a lower hardness than that of the second metal member and a higher hardness than that of the first metal member. By doing so, the plastic flow of the third metal layer, which has a viscosity lower than that of the second metal member 20 and higher than that of the first metal member 10 at the time of plastic flow, changes the bonding state of the outline of the processing region 5. improve and improve reliability.

It is preferable that the first metal member 10 against which the rotary tool 30 is pressed is made of a metal having a lower melting point than the second metal member 20 . By doing so, it is possible to prevent the occurrence of poor bonding and defects. If the first metal member 10 into which the rotary tool 30 is inserted has a higher melting point, the second metal member 20, which is the mating member, melts when the temperature of the first metal member 10 becomes high enough to cause plastic flow. This may result in poor bonding or defects. By using a metal having a lower melting point than the second metal member 20 for the first metal member 10 into which the rotary tool 30 is inserted, it is possible to prevent the occurrence of the above problems.

It is preferable that the metal forming the third metal layer has a lower melting point than that of the second metal member and a higher melting point than that of the first metal member. By doing so, the plastic flow of the third metal layer 40, which has a smaller fluidity than the second metal member 20 and a larger fluidity than the first metal member 10 at the time of plastic flow, joins the outline of the processing region 5. Improving conditions to improve reliability.

For example, an aluminum-based material can be used as the first metal member 10 and a copper-based material can be used as the second metal member 20 . Zinc, tin, or the like can be used as a material for forming the third metal layer 40 .

Of course, the present invention is not intended to be limited to the above combinations.

[Effects of Embodiment]
In the method of joining dissimilar metals according to the above embodiment, the first metal member 10 and the second metal member 20 of different types are prepared, and first, the first metal member 10 and the second metal member 20 are overlap. Next, a rotating tool 30 that rotates about its axis is pressed from the side of the first metal member 10 , and the interface between the first metal member 10 and the second metal member 20 is pressed by the rotating tool 30 . The working area 5 is joined.
At this time, of the boundary surface between the first metal member 10 and the second metal member 20, the portion along the contour of the planned processing region 5 scheduled to be processed by the rotary tool 30 is coated with the first metal member. A third metal layer 40 is interposed to promote bonding between the metal member 10 and the second metal member 20 . Furthermore, the third metal layer 40 is not interposed inside the portion along the contour.
By doing so, the bonding state of the contour portion of the processing region 5 is improved and the reliability is improved. can get. Two metal members of different types can be superimposed on each other and joined well by using friction stir.

In the method of joining dissimilar metals according to the above-described embodiment, the first metal member 10 against which the rotary tool 30 is pressed is made of a metal having a hardness lower than that of the second metal member 20 .
Since the rotary tool is pressed only against the first metal member 10 having low viscosity during plastic flow, adhesion of metal to the rotary tool 30 is suppressed, and the frequency of maintenance of the rotary tool 30 can be reduced. In addition, since the energy required to generate plastic flow is small, it is advantageous in saving power.

In the method for joining dissimilar metals according to the above embodiment, the metal constituting the third metal layer 40 is a metal having a hardness lower than that of the second metal member 20 and a hardness higher than that of the first metal member 10. do.
By doing so, the bonding state of the contour portion of the processing area 5 is improved to improve the reliability.

In the method of joining dissimilar metals according to the above embodiment, the first metal member 10 against which the rotary tool 30 is pressed is made of a metal having a lower melting point than the second metal member 20 .
If the melting point of the first metal member 10 against which the rotary tool 30 is pressed is higher than that of the first metal member 10, the second metal member 20, which is the mating member, melts when the temperature of the first metal member 10 becomes high enough to cause plastic flow. In the beginning, there is a risk of poor bonding and defects. By using a metal having a lower melting point than that of the second metal member 20 for the first metal member 10 against which the rotary tool 30 is pressed, it is possible to prevent the occurrence of the above problems.

In the method of joining dissimilar metals according to the above-described embodiment, the metal forming the third metal layer 40 has a lower melting point than that of the second metal member 20 and a higher melting point than that of the first metal member 10. do.
By doing so, the bonding state of the contour portion of the processing area 5 is improved to improve the reliability.

[Modification]
Although particularly preferred embodiments of the present invention have been described above, the present invention is not intended to be limited to the illustrated embodiments, and can be implemented in various ways, and the present invention includes various modifications. It is the intention to

1: anvil 3: boundary surface 5: processing area 5A: planned processing area 10: first metal member 20: second metal member 30: rotary tool 40: third metal layer

Claims (5)

preparing a first metal member and a second metal member of different types,
Overlapping the first metal member and the second metal member,
By pressing an axially rotating rotary tool from the side of the first metal member, a region of the boundary surface between the first metal member and the second metal member to be processed by the rotary tool is joined. When doing
The first metal member and the second metal member are formed on the boundary surface between the first metal member and the second metal member along the contour of the planned processing area scheduled to be processed by the rotary tool. A method for joining dissimilar metals, wherein a third metal layer is interposed to promote joining of the metal members, and the third metal layer is not interposed inside a portion along the contour. 2. The method of joining dissimilar metals according to claim 1, wherein the first metal member against which the rotary tool is pressed is made of a metal having a hardness lower than that of the second metal member. 3. The method of joining dissimilar metals according to claim 2, wherein the metal constituting the third metal layer is a metal having a hardness lower than that of the second metal member and higher than that of the first metal member. 2. The method of joining dissimilar metals according to claim 1, wherein the first metal member against which the rotary tool is pressed is made of a metal having a melting point lower than that of the second metal member. 5. The method of joining dissimilar metals according to claim 4, wherein the metal forming the third metal layer has a melting point lower than that of the second metal member and higher than that of the first metal member.

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