JP6645615B2 - Joining method - Google Patents

Description

  The present invention relates to a joining method.

  2. Description of the Related Art There is known a technique of performing friction stir welding using a rotary tool on an abutting portion formed by abutting an end surface of a first metal member and an end surface of a second metal member (see Patent Document 1). In the joining method, a rotary tool is relatively moved around the butted portion, and friction stir welding is performed over the entire circumference of the butted portion.

JP 2008-307570 A

  However, when the area of the butted portion is large, the stirring pin of the rotating tool cannot be inserted to the center of the first metal member and the second metal member. Therefore, the portions to be joined by the friction stir welding are only the outer periphery of the first metal member and the second metal member, and the center portion is not joined. Therefore, there is a problem that the joining strength between the first metal member and the second metal member is low.

  From such a viewpoint, an object of the present invention is to provide a joining method that can increase joining strength when friction stir joining is performed between a first metal member and a second metal member.

In order to solve such a problem, the present invention provides a preparation step of preparing a first metal member and a second metal member made of an aluminum alloy, and overlapping surfaces of the first metal member and the second metal member. When forming an overlapped portion by superimposing, a superposing step of sandwiching an Al-Si-Mg based single-layer brazing sheet between the superposed surfaces, and after the superposing step, the first metal member and the A surface brazing step of heating the single-layer brazing sheet to a solidus temperature or higher while pressing the second metal member to braze the first metal member and the second metal member, and After the attaching step, the stirring pin of the rotating tool is inserted from a side surface of the first metal member and the second metal member, and the entirety of the stirring tool while the stirring pin is in contact with both the first metal member and the second metal member. Week Over and characterized in that it comprises a friction stirring step for stirring friction the polymerization unit.
Further, the present invention provides a preparation step of preparing a first metal member and a second metal member made of an aluminum alloy, and forming a superposed portion by overlapping the superposed surfaces of the first metal member and the second metal member. When doing, a superposition step of sandwiching an Al-Si-Mg based single-layer brazing sheet between the superposition surfaces, and after the superposition step, pressing the first metal member and the second metal member A surface brazing step of heating the single-layer brazing sheet to a temperature equal to or higher than the solidus temperature of the single-layer brazing sheet while brazing the first metal member and the second metal member, and stirring the rotating tool after the surface brazing step A pin is inserted from the surface of the second metal member, and the polymerization is performed over the entire circumference while contacting the stirring pin with both the first metal member and the second metal member or only the second metal member. Department And friction stir step of friction stir, characterized in that it comprises a.
Further, the present invention provides a preparation step of preparing a first metal member and a second metal member made of aluminum alloy having different areas of a superimposed surface to be superimposed, and superimposing the first metal member and the second metal member. An overlapping step of sandwiching an Al-Si-Mg-based single-layer brazing sheet between the overlapping surfaces when forming overlapping portions by overlapping the surfaces, and after the overlapping step, the first metal Heating the single-layer brazing sheet to a solidus temperature or higher while pressing the member and the second metal member, and a surface brazing step of surface brazing the first metal member and the second metal member, After the surface brazing step, a stirring pin of the rotating tool is inserted from an inner corner formed by the first metal member and the second metal member, and a friction stir step of friction-stirring the overlapped portion over the entire circumference, To And wherein the Mukoto.

  According to this joining method, the central portions of the first metal member and the second metal member are joined by surface brazing, and the outer peripheral edges are joined by friction stir welding, so that joining strength can be increased.

  Also, before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral portion of the superposed surface of the first metal member and the superposed surface of the second metal member, In the overlapping step, it is preferable that the single-layer brazing sheet is sandwiched inside the concave groove on the overlapping surface.

  According to such a joining method, the brazing material extruded outward during the surface brazing process accumulates in the groove. This can prevent the brazing material from leaking out of the first metal member and the second metal member.

Further, in the friction stirring step, it is preferable that the friction stirring is performed in a state where only the stirring pin of the rotating tool is in contact with both the first metal member and the second metal member.
Further, in the friction stir step, friction stir is performed in a state where only the stirring pin of the rotating tool is in contact with both the first metal member and the second metal member or only the second metal member. Is preferred.

  According to this joining method, the load on the friction stirrer can be reduced.

  Further, in the friction stir step, it is preferable that the rotary tool is relatively moved outside the groove to perform friction stir.

Further, the present invention provides a preparation step of preparing a first metal member and a second metal member made of an aluminum alloy, and forming an overlapped portion by overlapping the superposed surfaces of the first metal member and the second metal member. When doing, a superimposing step of sandwiching a copper foil or a copper alloy foil between the superimposed surfaces, after the superimposing step, while pressing the first metal member and the second metal member to 510 ℃ or more A diffusion bonding step of heating and diffusion bonding the first metal member and the second metal member; and after the diffusion bonding step, a stirring pin of a rotating tool is attached to a side surface of the first metal member and the second metal member. And a friction stir step of friction-stirring the overlapped portion over the entire circumference.
Further, the present invention provides a preparation step of preparing a first metal member and a second metal member made of an aluminum alloy, and forming an overlapped portion by overlapping the superposed surfaces of the first metal member and the second metal member. When doing, a superimposing step of sandwiching a copper foil or a copper alloy foil between the superimposed surfaces, after the superimposing step, while pressing the first metal member and the second metal member to 510 ℃ or more Heating, a diffusion bonding step of diffusion bonding the first metal member and the second metal member, and after the diffusion bonding step, a stirring pin of a rotary tool is inserted from the surface of the second metal member, and the stirring is performed. A friction stir step of friction stirring the overlapping portion over the entire circumference while contacting the pin with both the first metal member and the second metal member, or only the second metal member. And
Further, the present invention provides a preparation step of preparing a first metal member and a second metal member made of an aluminum alloy having different areas of superimposed surfaces to be superimposed, and superimposing the first metal member and the second metal member. When superimposing surfaces to form an overlapped portion, a superposing step of sandwiching a copper foil or a copper alloy foil between the superposed surfaces, and after the superposing step, the first metal member and the second A diffusion joining step of diffusing and joining the first metal member and the second metal member while heating the metal member to 510 ° C. or higher while pressing the metal member; A friction stir step of inserting from the inner corner formed by the member and the second metal member and friction-stirring the overlapped portion over the entire circumference.

  According to such a joining method, the central portions of the first metal member and the second metal member are diffusion-bonded, and the outer peripheral edges are friction-stir-welded, so that the joining strength can be increased.

  Also, before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral portion of the superposed surface of the first metal member and the superposed surface of the second metal member, In the overlapping step, it is preferable that the copper foil or the copper alloy foil be sandwiched inside the concave groove in the overlapping surface.

  According to such a bonding method, the Al-Cu-Si melt extruded outward during the diffusion bonding step accumulates in the groove. Thereby, it is possible to prevent the Al-Cu-Si melt from leaking out of the first metal member and the second metal member.

Further, in the friction stirring step, it is preferable that the friction stirring is performed in a state where only the stirring pin of the rotating tool is in contact with both the first metal member and the second metal member.
Further, in the friction stir step, friction stir is performed in a state where only the stirring pin of the rotating tool is in contact with both the first metal member and the second metal member or only the second metal member. Is preferred.

  According to this joining method, the load on the friction stirrer can be reduced.

  Further, in the friction stir step, it is preferable that the rotary tool is relatively moved outside the groove to perform friction stir.

  According to such a joining method, it is possible to prevent copper from being mixed into the plasticized region.

  According to the joining method according to the present invention, the joining strength can be increased.

FIG. 3 is an exploded perspective view illustrating a preparation step of the bonding method according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating an overlapping step of the bonding method according to the first embodiment. It is sectional drawing which shows the surface brazing process of the joining method concerning 1st embodiment. It is a perspective view showing the friction stir process of the joining method concerning a first embodiment. It is sectional drawing which shows the friction stirring process of the joining method concerning 1st embodiment. It is a perspective view showing the friction stir process of the joining method concerning a second embodiment of the present invention. It is sectional drawing which shows the friction stirring process of the joining method concerning 2nd embodiment. It is an exploded perspective view showing the preparation process of the joining method concerning a third embodiment of the present invention. It is sectional drawing which shows the superposition process of the joining method which concerns on 3rd embodiment. It is sectional drawing which shows the surface brazing process of the joining method concerning 3rd embodiment. It is a perspective view showing the friction stir process of the joining method concerning a third embodiment. It is sectional drawing which shows the friction stir process of the joining method concerning 3rd embodiment. It is an exploded perspective view showing the preparation process of the joining method concerning a 4th embodiment of the present invention. It is sectional drawing which shows the superposition process of the joining method concerning 4th Embodiment. It is sectional drawing which shows the diffusion bonding process of the bonding method concerning 4th Embodiment. It is a perspective view showing the friction stir process of the joining method concerning a 4th embodiment. It is sectional drawing which shows the friction stirring process of the joining method concerning 4th Embodiment. It is a perspective view showing the friction stir process of the joining method concerning a 5th embodiment of the present invention. It is sectional drawing which shows the friction stirring process of the joining method concerning 5th Embodiment. It is an exploded perspective view showing a preparation process of a joining method concerning a sixth embodiment of the present invention. It is sectional drawing which shows the superposition process of the joining method which concerns on 6th Embodiment. It is sectional drawing which shows the diffusion bonding process of the bonding method concerning 6th Embodiment. It is a perspective view showing the friction stir process of the joining method concerning a 6th embodiment. It is sectional drawing which shows the friction stirring process of the joining method concerning 6th Embodiment.

[First embodiment]
A first embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, in the joining method according to the first embodiment, a case where the first metal member 2 and the second metal member 3 are joined to form the structure 1 is illustrated. In the description, “front surface” means a surface opposite to “back surface”. In the joining method according to the present embodiment, a preparation step, a groove forming step, a superposition step, a surface brazing step, and a friction stir step are performed.

  The preparation step is a step of preparing the first metal member 2 and the second metal member 3. The first metal member 2 is a metal member having a substantially rectangular parallelepiped shape. The first metal member 2 is made of an aluminum alloy. The four corners of the first metal member 2 are formed with round chamfers. The second metal member 3 has the same shape and material as the first metal member 2. The solidus temperature of the first metal member 2 and the second metal member 3 can be set, for example, to about 580 to 650 ° C. In the present embodiment, the first metal member 2 and the second metal member 3 The solidus temperature is about 643 ° C. because of the wrought material 3003 alloy.

  The groove forming step is a step of forming a groove on at least one of the overlapping surfaces of the first metal member 2 and the second metal member 3. In the groove forming step of the present embodiment, a groove 14 is formed on the front surface 13 of the first metal member 2 and a groove 24 is formed on the back surface 23 of the second metal member 3. The concave groove 14 is formed in a frame shape along the outer peripheral edge inside the outer peripheral edge of the first metal member 2. The cross-sectional shape of the concave groove 14 is not particularly limited, but is a semicircular cross-section in the present embodiment. In the groove forming step, a groove 24 is formed on the back surface 23 of the second metal member 3 in the same manner as the groove 14.

  As shown in FIG. 2, in the overlapping step, when the overlapping surfaces of the first metal member 2 and the second metal member 3 are overlapped to form the overlapped portion J1, Al- This is a step of sandwiching the Si-Mg based single-layer brazing sheet 4. The brazing sheet 4 is a fluxless brazing specification, and is a thin single-layer sheet made of an Al-Si-Mg alloy brazing material. The brazing sheet 4 is formed in a size arranged inside the concave grooves 14 and 24. The thickness of the brazing sheet 4 is not particularly limited, but is, for example, about 20 to 100 μm in the present embodiment.

  In the overlapping step, the front surface (overlapping surface) 13 of the first metal member 2 and the back surface (the back surface) of the second metal member 3 (with the brazing sheet 4 interposed between the first metal member 2 and the second metal member 3). (Overlapping surface) 23. Thereby, the overlapping portion J1 is formed.

The surface brazing step is a step of performing surface brazing as shown in FIG. Here, Si in the brazing sheet 4 is an element for lowering the liquidus temperature of the brazing sheet 4 and improving the wettability during surface brazing according to the content thereof. If the Si content is less than 1.0% by mass, the temperature of the liquidus of the brazing sheet 4 becomes too high, and even when the brazing temperature reaches a predetermined brazing temperature, the dissolution of the brazing sheet 4 becomes insufficient, There is a possibility that sufficient brazing strength (shear stress) cannot be obtained. Conversely, if the Si content exceeds 12% by mass, the possibility that primary Si precipitates (crystallizes) in the center of the ingot during casting increases, and if a healthy cold-rolled sheet is obtained, However, it is difficult to obtain a brazing sheet 4 having a microscopically uniform structure.
Therefore, the Si content in the brazing material is in the range of 1.0 to 12% by mass. A more preferred Si content is in the range of 2.0 to 12% by mass. More preferred Si content is 3.
It is in the range of 0 to 12% by mass.

Since Mg in the brazing sheet 4 itself acts as a reducing agent by being oxidized, the aluminum alloy members (the first metal member 2 and the second metal member 3) and the brazing material of the brazing sheet 4 are heated by brazing. It is considered to be an element for suppressing the oxidation of aluminum at the interface with, and improving the wettability during brazing of the surface. If the Mg content is less than 0.1% by mass, depending on the brazing temperature and the holding time, the effect is insufficient, and sufficient brazing strength (shear stress) may not be obtained. . Conversely, when the Mg content exceeds 5.0% by mass, the load on the roll when hot rolling the ingot becomes large, and ear cracks occur, so that cold rolling becomes difficult. Considering the workability of the brazing material, the lower the Mg content, the better.
Therefore, the Mg content in the brazing material is in the range of 0.1 to 5.0% by mass. A more preferred Mg content is in the range of 0.1 to 4.0% by mass. A more preferred Mg content is 0.1.
It is in the range of 1 to 3.0% by mass.

  The remainder of the brazing sheet 4 is composed of Al and inevitable impurities. Examples of the inevitable impurities include Fe, Cu, Mn, and Zn. For these elements, Fe: less than 1.0% by mass, Cu: less than 1.0% by mass, Mn: less than 1.0% by mass, If the Zn content is less than 1.0% by mass, the effects of the present invention are not hindered. Therefore, the content of each of the components as inevitable impurities is preferably less than 1.0% by mass.

  In the surface brazing step, surface brazing is performed by applying a pressing force in a direction in which the first metal member 2 and the second metal member 3 approach each other under predetermined conditions. The conditions of the surface brazing step may be appropriately set according to the alloy composition of the first metal member 2, the second metal member 3, the brazing sheet 4, and the like. In the present embodiment, for example, the pressing force is set to about 10 KPa or more, the atmosphere is an inert gas, and the pressing state is maintained for 2 minutes or more. The holding temperature is preferably set to be equal to or higher than the solidus temperature of the brazing sheet 4 and lower than the solidus temperatures of the first metal member 2 and the second metal member 3. In the present embodiment, the brazing sheet 4 has a solidus temperature of 560 ° C., and the first metal member 2 and the second metal member 3 are made of wrought 3003 alloy (solidus temperature: 643 ° C.). It is desirable to set the holding temperature at the time of attachment heating to 560 ° C to less than 643 ° C. As the inert gas, for example, nitrogen, argon, and helium can be used. As the nitrogen gas, it is desirable to use industrial nitrogen gas whose oxygen concentration is regulated to 10 ppm or less.

  Thereby, the first metal member 2 and the second metal member 3 are surface brazed. Since the brazing sheet 4 is a single-layer brazing sheet in this embodiment, the cost can be reduced. In the surface brazing step, the surface brazing is performed without using a flux in an inert gas atmosphere. Thereby, in the surface brazing step, a specific surface pressure is applied in a state where the surfaces are in contact with each other to melt the brazing sheet 4 and the interface between the aluminum alloy members (the first metal member 2 and the second metal member 3). , And the molten brazing material can be actively discharged from the interface.

  As shown in FIG. 3, by the surface brazing process, the molten brazing material Q is discharged outward from the central portion and stored in the concave grooves 14 and 24. In other words, the recesses 14 and 24 form a brazing material reservoir for storing the brazing material that has flowed out.

  As shown in FIG. 4, the friction stir process is a process of performing friction stir welding over the entire circumference of the overlapping portion J1 using the rotating tool F for welding. The joining rotary tool F corresponds to a “rotating tool” in the claims.

  The joining rotary tool F includes a connecting portion F1 and a stirring pin F2, and is made of, for example, tool steel. The connecting portion F1 is a portion to be attached to a friction stirrer (not shown), and has a columnar shape. The stirring pin F2 hangs down from the connecting portion F1 and is coaxial with the connecting portion F1. The stirring pin F2 tapers as it moves away from the connecting portion F1. A spiral groove is engraved on the outer peripheral surface of the stirring pin F2. In this embodiment, in order to rotate the joining rotary tool F clockwise, the spiral groove is formed counterclockwise from the base end toward the tip.

  In addition, when rotating the joining rotary tool F counterclockwise, it is preferable to form the spiral groove clockwise from the base end toward the tip end. By setting the spiral groove in this way, the metal plastically fluidized at the time of friction stirring is guided to the tip side of the stirring pin F2 by the spiral groove. Thereby, the amount of metal that overflows to the outside of the metal members to be joined (the first metal member 2 and the second metal member 3) can be reduced.

  In the friction stir process, the joining rotating tool F rotated right is inserted vertically from the side surface 12 of the first metal member 2 and the side surface 22 of the second metal member 3 and relatively moved along the overlapping portion J1. . In the friction stir step, the connection portion F1 is separated from the metal member to be joined, and friction stir is performed with the base end side of the stirring pin F2 exposed. In the present embodiment, it is preferable to attach the joining rotary tool F to a robot arm provided with a rotary drive unit such as a spindle unit at the tip. Thus, the rotation center axis of the joining rotary tool F can be easily inclined.

  The moving direction of the joining rotary tool F may be either direction, but in the present embodiment, the joining metal member is set to be counterclockwise when viewed from above. As shown in FIG. 5, the stirring pin F2 is brought into contact with both the first metal member 2 and the second metal member 3. A plasticizing region W1 is formed on the movement trajectory of the joining rotary tool F. In the friction stir step, it is preferable that the beginning and the end of the plasticizing region W1 overlap.

  According to the joining method described above, since the central portions of the first metal member 2 and the second metal member 3 are joined by surface brazing, and the outer peripheral edges are joined by friction stir welding, the joining strength can be increased. . Here, in general, when the surface brazing is performed, there is a possibility that the molten brazing material leaks from the overlapping portion to the outside. However, in the present embodiment, since the brazing material pool is provided by the concave grooves 14 and 24, it is possible to prevent the molten brazing material from leaking out of the first metal member 2 and the second metal member 3.

  Further, in the friction stir step, only the stirring pin F2 of the welding rotary tool F is brought into contact with the metal member to be joined, so that the load on the friction stir device can be reduced.

  In the present embodiment, the configuration is as described above, but another configuration may be used. For example, the rotating tool may be configured by a shoulder portion and a stirring pin protruding from a lower end surface of the shoulder portion. In the friction stir process, the friction stir welding may be performed in a state where the shoulder portion of the rotary tool is pressed into the metal member to be welded. In the friction stirring process, the insertion depth and the positions of the grooves 14 and 24 may be set so that the stirring pin F2 reaches the grooves 14 and 24. Thereby, the gap between the concave grooves 14 and 24 can be filled with the metal, so that it is possible to prevent the occurrence of a gap inside the structure 1. In this case, it is preferable to set the insertion depth so that the stirring pin F2 does not directly contact the brazing material Q so that the brazing material Q is not involved in the plasticizing region W1.

[Second embodiment]
Next, a joining method according to a second embodiment of the present invention will be described. In the joining method according to the second embodiment, a preparation step, a groove forming step, an overlapping step, a surface brazing step, and a friction stir step are performed. In the second embodiment, a description will be given focusing on portions different from the first embodiment.

  In the preparation step, as shown in FIG. 6, a first metal member 2 and a second metal member 3 that are thinner than in the first embodiment are prepared. The groove forming step, the overlapping step, and the surface brazing step are the same as in the first embodiment.

  As shown in FIGS. 6 and 7, the friction stir process is a process of performing friction stir welding over the entire periphery of the overlapping portion J1 using the rotating tool F for welding. In the friction stir step, the joining rotating tool F rotated clockwise to the right perpendicular to the surface 21 is inserted into the start position Sp set on the surface 21 of the second metal member 3, and The joining rotary tool F is caused to make a complete rotation along the outer peripheral edge and relatively moved. In the friction stir process, the start and end of the plasticizing region W1 are made to overlap. In the present embodiment, the movement route of the joining rotary tool F is set outside the concave grooves 14 and 24.

  In the friction stir process, the insertion depth is set such that the stirring pin F2 contacts both the first metal member 2 and the second metal member 3. In the friction stir step, the insertion depth may be set such that the stirring pin F2 contacts only the second metal member 3. In this case, the overlapping portion J1 is plastically fluidized by friction heat between the stirring pin F2 and the second metal member 3, and is joined.

  According to the second embodiment described above, substantially the same effects as those of the first embodiment can be obtained. In the joining method according to the second embodiment, the outside of the plasticized region W1 may be cut off at the boundary of the plasticized region W1. At this time, the cut can be easily performed by using the depression formed in the plasticized region W1 as a boundary. The depression is a portion where the surface of the plasticized region W1 is deepened by the friction stir process. At this time, in the friction stir step, it is preferable to set the joining conditions so that burrs are formed (aggregated) outside the plasticized region W1. The welding conditions include the rotation speed, rotation direction, traveling direction, moving speed (feed speed), inclination angle (taper angle) of the stirring pin F2, the metal member to be welded (first metal member 2, It is determined by each element such as the material of the bimetallic member 3), the thickness of the metal member to be joined, and the combination of these elements. If the side where burrs are generated or the side where many burrs are generated is set outside the plasticized region W1 according to the joining conditions, the burrs can be cut together.

[Third embodiment]
Next, a joining method according to a third embodiment of the present invention will be described. In the bonding method according to the third embodiment, a preparation step, a groove forming step, an overlapping step, a surface brazing step, and a friction stir step are performed. As shown in FIG. 8, the third embodiment is different from the first embodiment in that the size of the first metal member 2A and the size of the second metal member 3A are different. In the third embodiment, a description will be given mainly of a portion different from the first embodiment.

  In the preparation step, a first metal member 2A and a second metal member 3A are prepared. The first metal member 2A and the second metal member 3A have a rectangular parallelepiped shape. The first metal member 2A is larger than the second metal member 3A.

  In the groove forming step, a groove 14 is formed on the surface 13 of the first metal member 2A. The concave groove 14 is formed in a frame shape along the outer peripheral edge of the first metal member 2A. In the third embodiment, no groove is formed in the second metal member 3A.

  In the superposing step, as shown in FIG. 9, the superimposed portion J2 is formed by superposing the front surface 13 of the first metal member 2A and the rear surface 23 of the second metal member 3A while sandwiching the single-layer brazing sheet 4 therebetween. Form. The brazing sheet 4 is sized to be arranged inside the concave groove 14.

  In the surface brazing step, as shown in FIG. 10, surface brazing is performed by applying a pressing force in a direction in which the first metal member 2 and the second metal member 3 approach each other under a predetermined condition. By the surface brazing process, the molten brazing material Q is discharged from the central portion to the outside, and is stored in the concave groove 14. In other words, the recess 14 and the back surface 23 of the second metal member 3A form a brazing material reservoir for storing the brazing material that has flowed out.

  In the friction stir process, as shown in FIG. 11, the joining rotary tool F is relatively moved at the inner corners of the first metal member 2A and the second metal member 3A to friction stir weld the overlapped portion J2. In the present embodiment, it is preferable to attach the joining rotary tool F to a robot arm provided with a rotary drive unit such as a spindle unit at the tip. Thereby, the inclination angle of the rotation center axis of the joining rotary tool F can be easily changed. In the friction stir process, first, the stirring pin F2 of the joining rotary tool F is inserted into the start position Sp set on the surface 13 of the first metal member 2A, and relatively moved toward the second metal member 3A. Then, as shown in FIG. 12, the rotation center axis of the joining rotary tool F is inclined outward, so that the rotation center axis is located at the inner corner formed by the surface 13 of the first metal member 2A and the side surface 22 of the second metal member 3A. Relative movement along.

  In the present embodiment, the moving direction of the joining rotary tool F is counterclockwise when viewed from above. The joining rotary tool F makes a round around the second metal member 3A and overlaps the start and end on the inner corner, and then joins at the end position set on the surface 13 of the first metal member 2A. Release the rotating tool F. Thereby, the structure 1A is formed.

  With the bonding method according to the third embodiment described above, substantially the same effects as in the first embodiment can be achieved. Also, as in the present embodiment, when the size of the first metal member 2A and the size of the second metal member 3A are different, that is, even when the sizes of the surfaces to be overlapped are different, it is preferable to perform the joining. Can be. Also, according to the third embodiment, the brazing material Q can be stored in the concave groove 14, so that the brazing material Q can be prevented from leaking to the outside.

  Although the embodiments of the present invention have been described above, design changes can be made as appropriate without departing from the spirit of the present invention. For example, the first metal members 2 and 2A and the second metal members 3 and 3A are cuboids, but may be other square shapes or columnar shapes. The concave groove may be omitted.

[Fourth embodiment]
A fourth embodiment of the present invention will be described in detail with reference to the drawings. As illustrated in FIG. 13, the joining method according to the fourth embodiment exemplifies a case in which a first metal member 102 and a second metal member 103 are joined to form a structure 101. In the bonding method according to the present embodiment, a preparation step, an overlapping step, a diffusion bonding step, and a friction stir step are performed.

  The preparation step is a step of preparing the first metal member 102 and the second metal member 103. The first metal member 102 is a metal member having a substantially rectangular parallelepiped shape. The first metal member 102 is made of an aluminum alloy. The four corners of the first metal member 102 are formed with round chamfers. The second metal member 103 has the same shape and material as the first metal member 102.

  As long as the first metal member 102 and the second metal member 103, which are the metal members to be joined, are made of an aluminum alloy, they may be wrought materials (for example, JIS A6000-based aluminum alloy) or castings. That is, as long as the metal material to be bonded contains Si, bonding with a copper alloy foil or a copper foil is possible even if the content of Si is 1% or less. However, this aluminum alloy needs to contain at least 0.1% by mass of Mg. If Mg is contained in the aluminum alloy in an amount of 0.1% by mass or more, Mg is preferentially oxidized on the surface of the aluminum alloy member in the diffusion bonding step, so that oxidation of aluminum can be prevented. At the interface between the foil 104 and the first metal member 102 and at the interface between the copper alloy foil 104 and the second metal member 103, mutual diffusion of copper and aluminum can be promoted smoothly. Thereby, the first metal member 102 and the second metal member 103 can be firmly joined.

  As shown in FIG. 14, when the overlapping surfaces of the first metal member 102 and the second metal member 103 are overlapped to form the overlapped portion J11, a copper alloy is formed between the overlapping surfaces. This is a step of sandwiching the foil 104. In the present embodiment, for example, a copper foil made of oxygen-free copper (JIS C-1020) is used as the copper alloy foil 104. The copper alloy foil 104 may be, for example, a copper alloy foil made of a Cu—Zn alloy or a Cu—Sn alloy. The copper alloy foil 104 is a thin single-layer sheet, and is formed to have a size that is arranged inside the overlapping surface of the first metal member 102 and the second metal member 103. The thickness of the copper alloy foil 104 is preferably as thin as possible, but is, for example, about 2 to 50 μm in the present embodiment. A copper foil may be used instead of the copper alloy foil 104.

  In the overlapping step, the surface (overlapping surface) 113 of the first metal member 102 and the back surface of the second metal member 103 are sandwiched between the first metal member 102 and the second metal member 103 with the copper alloy foil 104 interposed therebetween. (Overlapping surface) 123 is superimposed. Thereby, the overlapping portion J11 is formed.

  The diffusion bonding step is a step of performing diffusion bonding as shown in FIG. Mg contained in the first metal member 102 and the second metal member 103 made of an aluminum alloy is considered to be an element that suppresses the oxidation of aluminum because it acts as a reducing agent by being oxidized by itself. When the oxidation of aluminum is suppressed, mutual diffusion of aluminum and copper at the interface between the copper alloy foil 104 and the first metal member 102 and the interface between the copper alloy foil 104 and the second metal member 103 can be smoothly promoted. it can. If the Mg content is less than 0.1% by mass, the effect is insufficient, depending on the heating temperature and the holding time, but there is a possibility that sufficient joining strength (shear stress) cannot be obtained. Therefore, the Mg content in the aluminum alloy member is set to a range of 0.1% by mass or more.

  In the diffusion bonding process, a pressing force is applied under a predetermined condition in a direction in which the first metal member 102 and the second metal member 103 approach to perform diffusion bonding. The conditions of the diffusion bonding step may be appropriately set depending on the alloy composition of the first metal member 102, the second metal member 103, and the copper alloy foil 104, and the like. In the present embodiment, for example, the pressing force is set to about 0.1 to 10 MPa, the atmosphere is an inert gas, and the pressing state is maintained for 2 minutes or more. The holding temperature needs to be set to 510 ° C. or higher. The holding temperature is preferably set to 520 ° C. or higher, more preferably 525 ° C. or higher. In the present embodiment, the copper alloy foil 104 is made of oxygen-free copper (JIS C-1020), and the first metal member 102 and the second metal member 103 are made of wrought JIS A6063 alloy. The holding temperature can be set to, for example, 525 to 550 ° C. As the inert gas, for example, nitrogen, argon, and helium can be used. As the nitrogen gas, it is desirable to use industrial nitrogen gas whose oxygen concentration is regulated to 10 ppm or less.

Thereby, the first metal member 102 and the second metal member 103 are diffusion-bonded. When the holding temperature in the diffusion bonding step is set to a relatively low temperature of 510 ° C., aluminum and copper are present at the interface between the first metal member 102 and the copper alloy foil 104 and at the interface between the second metal member 103 and the copper alloy foil 104. And mutual diffusion progresses. The diffusion of Al into the copper alloy foil 104 forms an intermetallic compound layer 105 between the first metal member 102 and the second metal member 103. This intermetallic compound is considered to be an Al ₂ Cu compound. When the holding temperature is set to 525 ° C., which is relatively high, at the interface between the first metal member 102 and the intermetallic compound layer 105 and at the interface between the second metal member 103 and the intermetallic compound layer 105, Interdiffusion occurs, the volume of the intermetallic compound layer 105 decreases with time, and a plurality of dispersed particulate intermetallic compounds (Al ₂ Cu) are formed at the joint between the first metal member 102 and the second metal member 103. Is left.

  In the present embodiment, a single-layer copper foil or copper alloy foil 104 is used, so that the cost can be reduced. In the diffusion bonding step, diffusion bonding is performed in an inert gas atmosphere. Thereby, in the diffusion bonding step, diffusion bonding is performed by applying a specific surface pressure in a state of surface contact, and the interface between the aluminum alloy members (the first metal member 102 and the second metal member 103) is formed by Al- The molten Al-Cu-Si can be positively discharged from the interface while being wetted by the Cu-Si melt.

  As shown in FIG. 16, the friction stir process is a process of performing friction stir welding over the entire periphery of the overlapping portion J11 using the rotating tool F for welding.

  In the friction stir process, the joining rotating tool F rotated right is inserted vertically from the side surface 112 of the first metal member 102 and the side surface 122 of the second metal member 103, and relatively moved along the overlapping portion J11. . The insertion depth of the joining rotary tool F may be set as appropriate, but in the present embodiment, it is set so that the stirring pin F2 does not contact the intermetallic compound layer 105. In the friction stir step, the connection portion F1 is separated from the metal member to be joined, and friction stir is performed with the base end side of the stirring pin F2 exposed. In the present embodiment, it is preferable to attach the joining rotary tool F to a robot arm provided with a rotary drive unit such as a spindle unit at the tip. Thus, the rotation center axis of the joining rotary tool F can be easily inclined.

  The moving direction of the joining rotary tool F may be either direction, but in the present embodiment, the joining metal member is set to be counterclockwise when viewed from above. As shown in FIG. 17, the stirring pin F2 is brought into contact with both the first metal member 102 and the second metal member 103. A plasticizing region W1 is formed on the movement trajectory of the joining rotary tool F. In the friction stir step, it is preferable that the joining rotating tool F is caused to make one round so that the starting end and the end of the plasticizing region W1 overlap.

  According to the joining method described above, the central portions of the first metal member 102 and the second metal member 103 are diffusion-bonded, and the outer peripheral edges are friction-stir-welded, so that the joining strength can be increased. Further, in the friction stir step, only the stirring pin F2 of the welding rotary tool F is brought into contact with the metal member to be joined, so that the load on the friction stir device can be reduced.

  In the present embodiment, the configuration is as described above, but another configuration may be used. For example, the rotating tool may be configured by a shoulder portion and a stirring pin protruding from a lower end surface of the shoulder portion. In the friction stir process, the friction stir welding may be performed in a state where the shoulder portion of the rotary tool is pressed into the metal member to be welded.

[Fifth embodiment]
Next, a joining method according to a fifth embodiment of the present invention will be described. In the bonding method according to the fifth embodiment, a preparation step, an overlapping step, a diffusion bonding step, and a friction stir step are performed. In the fifth embodiment, a description will be given focusing on portions different from the fourth embodiment.

  In the preparation step, as shown in FIG. 18, a first metal member 102 and a second metal member 103 that are thinner than in the fourth embodiment are prepared. The overlapping step and the diffusion bonding step are the same as in the fourth embodiment.

  As shown in FIGS. 18 and 19, the friction stir welding step is a step of performing friction stir welding over the entire circumference of the overlapping portion J11 using the joining rotary tool F. In the friction stir step, a joining rotating tool F rotated clockwise with respect to the surface 121 is inserted perpendicularly to the surface 121 at a start position Sp set on the surface 121 of the second metal member 103. The rotation tool F for joining is relatively moved along the outer peripheral edge on the surface 121 of 103. In the friction stir process, the start and end of the plasticizing region W1 are made to overlap.

  In the friction stir process, the insertion depth is set so that the stirring pin F2 contacts both the first metal member 102 and the second metal member 103. In the friction stir process, the insertion depth may be set so that the stirring pin F2 contacts only the second metal member 103. In this case, the overlapping portion J11 plastically fluidizes due to frictional heat between the stirring pin F102 and the second metal member 103 and is joined.

  According to the fifth embodiment described above, substantially the same effects as those of the fourth embodiment can be obtained. In the joining method according to the fifth embodiment, the outside of the plasticized region W1 may be cut off at the boundary of the plasticized region W1. At this time, the cut can be easily performed by using the depression formed in the plasticized region W1 as a boundary. The depression is a portion where the surface of the plasticized region W1 is deepened by the friction stir process. At this time, in the friction stir step, it is preferable to set the joining conditions so that burrs are formed outside the plasticized region W1. The welding conditions include the rotation speed, rotation direction, traveling direction, moving speed (feed speed), inclination angle (taper angle) of the stirring pin F2, the metal member to be welded (the first metal member 102, It is determined by each element such as the material of the bimetal member 103), the thickness of the metal member to be joined, and the combination of these elements. If the side on which burrs are generated or the side on which burrs are generated is set so as to be outside the plasticized region W1 according to the joining conditions, the end portions can be cut off together with the burrs.

[Sixth embodiment]
Next, a joining method according to a sixth embodiment of the present invention will be described. In the bonding method according to the sixth embodiment, a preparation step, an overlapping step, a diffusion bonding step, and a friction stir step are performed. As shown in FIG. 20, the sixth embodiment differs from the fourth embodiment in that the sizes of the first metal member 102A and the second metal member 103A are different. In the sixth embodiment, a description will be given focusing on portions different from the fourth embodiment.

  In the preparation step, a first metal member 102A and a second metal member 103A are prepared. The first metal member 102A and the second metal member 103A have a rectangular parallelepiped shape. The first metal member 102A is larger than the second metal member 103A.

  In the superimposing step, as shown in FIG. 21, while sandwiching the copper alloy foil 104 between the front surface 113 of the first metal member 102A and the back surface 123 of the second metal member 103A, The overlapping portion J12 is formed by overlapping the back surface 123 of the second metal member 103A. The copper alloy foil 104 has a size arranged inside the back surface 123 of the second metal member 103A.

  In the diffusion bonding step, as shown in FIG. 22, diffusion bonding is performed by applying a pressing force under a predetermined condition in a direction in which the first metal member 102A and the second metal member 103A approach each other.

  In the friction stir process, as shown in FIG. 23, the joining rotary tool F is relatively moved at the inner corners of the first metal member 102A and the second metal member 103A to friction stir weld the overlapped portion J12. In the present embodiment, it is preferable to attach the joining rotary tool F to a robot arm provided with a rotary drive unit such as a spindle unit at the tip. Thereby, the inclination angle of the rotation center axis of the joining rotary tool F can be easily changed. In the friction stirring step, first, the stirring pin F2 of the joining rotary tool F is inserted into the start position Sp set on the surface 113 of the first metal member 102A, and relatively moved toward the second metal member 103A. Then, as shown in FIG. 24, the rotation center axis of the joining rotary tool F is inclined outward to form an inner corner formed by the surface 113 of the first metal member 102A and the side surface 122 of the second metal member 103A. Relative movement along.

  In the present embodiment, the moving direction of the joining rotary tool F is counterclockwise when viewed from above. The rotating tool F for joining, while making a round around the second metal member 103A and overlapping the start and end on the inner corner, joins at the end position set on the surface 113 of the first metal member 102A. Release the rotating tool F. As a result, a structure 101A is formed.

  With the joining method according to the sixth embodiment described above, substantially the same effects as in the fourth embodiment can be achieved. Also, as in the present embodiment, when the size of the first metal member 102A and the size of the second metal member 103A are different, that is, even when the size of the surfaces to be overlapped is different, it is preferable to perform the joining. Can be.

DESCRIPTION OF SYMBOLS 1 Structure 2 First metal member 3 Second metal member 4 Brazing sheet J1 Overlapping part W1 Plasticizing region

Claims (18)

A preparation step of preparing a first metal member and a second metal member made of an aluminum alloy,
When the superposed surfaces of the first metal member and the second metal member are superimposed to form an overlapped portion, an Al-Si-Mg-based single-layer brazing sheet is sandwiched between the superposed surfaces. Matching process,
After the overlapping step, the first metal member and the second metal member are heated to a solidus temperature or higher of the single-layer brazing sheet while pressing the second metal member, and the first metal member and the second metal member are heated. A surface brazing process for surface brazing;
After the surface brazing step, a stirring pin of a rotating tool is inserted from a side surface of the first metal member and the second metal member, and the stirring pin is brought into contact with both the first metal member and the second metal member. A friction stir step of friction-stirring the overlapped portion over one entire circumference. Before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral edge of the superposed surface of the first metal member and the superposed surface of the second metal member,
2. The bonding method according to claim 1, wherein in the overlapping step, the single-layer brazing sheet is sandwiched inside the concave groove on the overlapping surface. 3.   3. The friction stir step, wherein friction stir is performed in a state where only the stirring pin of the rotary tool is in contact with both the first metal member and the second metal member. 4. The joining method according to 1. A preparation step of preparing a first metal member and a second metal member made of an aluminum alloy,
When the superposed surfaces of the first metal member and the second metal member are superimposed to form an overlapped portion, an Al-Si-Mg-based single-layer brazing sheet is sandwiched between the superposed surfaces. Matching process,
After the superposition step, the first metal member and the second metal member are heated to a temperature equal to or higher than the solidus temperature of the single-layer brazing sheet while pressing the first metal member and the second metal member. Brazing surface brazing process,
After the surface brazing step, insert the stirring pin of the rotating tool from the surface of the second metal member, the stirring pin both the first metal member and the second metal member, or only the second metal member And a friction stir step of friction-stirring the overlapped portion over the entire circumference while contacting the superposed portion. Before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral edge of the superposed surface of the first metal member and the superposed surface of the second metal member,
5. The bonding method according to claim 4, wherein in the overlapping step, the single-layer brazing sheet is sandwiched inside the concave groove on the overlapping surface.   In the friction stir step, friction stirring is performed in a state where only the stirring pin of the rotary tool is in contact with both the first metal member and the second metal member, or only the second metal member. The joining method according to claim 4 or 5, wherein   The method according to claim 5, wherein, in the friction stir step, the rotary tool is relatively moved outside the concave groove to perform friction stir. A preparation step of preparing a first metal member and a second metal member made of an aluminum alloy having different areas of a superimposed surface to be superimposed,
When the superposed surfaces of the first metal member and the second metal member are superimposed to form an overlapped portion, an Al-Si-Mg-based single-layer brazing sheet is sandwiched between the superposed surfaces. Matching process,
After the superposition step, the first metal member and the second metal member are heated to a temperature equal to or higher than the solidus temperature of the single-layer brazing sheet while pressing the first metal member and the second metal member. Brazing surface brazing process,
After the surface brazing step, a stir pin of a rotary tool is inserted from an inner corner formed by the first metal member and the second metal member, and a friction stir step of friction-stirring the overlapped portion over the entire circumference. And a joining method. Before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral edge of the superposed surface of the first metal member and the superposed surface of the second metal member,
9. The bonding method according to claim 8, wherein in the overlapping step, the single-layer brazing sheet is sandwiched inside the concave groove in the overlapping surface. A preparation step of preparing a first metal member and a second metal member made of an aluminum alloy,
When forming a superposed portion by superimposing the superposed surfaces of the first metal member and the second metal member, a superposing step of sandwiching a copper foil or a copper alloy foil between the superposed surfaces,
After the superposing step, the first metal member and the second metal member are heated to 510 ° C. or more while being pressed, and a diffusion bonding step of diffusion bonding the first metal member and the second metal member is performed,
After the diffusion bonding step, a friction stir step of inserting a stirring pin of a rotary tool from a side surface of the first metal member and the second metal member and friction stir the overlapping portion over the entire circumference. Characteristic joining method. Before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral edge of the superposed surface of the first metal member and the superposed surface of the second metal member,
The bonding method according to claim 10, wherein, in the overlapping step, the copper foil or the copper alloy foil is sandwiched inside the concave groove in the overlapping surface.   12. The friction stir step in which friction stirring is performed in a state where only the stirring pin of the rotary tool is in contact with both the first metal member and the second metal member. 3. The joining method according to 1. A preparation step of preparing a first metal member and a second metal member made of an aluminum alloy,
When forming a superposed portion by superimposing the superposed surfaces of the first metal member and the second metal member, a superposing step of sandwiching a copper foil or a copper alloy foil between the superposed surfaces,
After the superposing step, the first metal member and the second metal member are heated to 510 ° C. or more while being pressed, and a diffusion bonding step of diffusion bonding the first metal member and the second metal member is performed,
After the diffusion bonding step, insert the stirring pin of the rotating tool from the surface of the second metal member, the stirring pin into both the first metal member and the second metal member, or only the second metal member A friction stir step of friction-stirring the overlapping portion over the entire circumference while making contact. Before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral edge of the superposed surface of the first metal member and the superposed surface of the second metal member,
14. The bonding method according to claim 13, wherein, in the overlapping step, the copper foil or the copper alloy foil is sandwiched inside the concave groove in the overlapping surface.   In the friction stir step, friction stirring is performed in a state where only the stirring pin of the rotating tool is in contact with both the first metal member and the second metal member, or only the second metal member. The bonding method according to claim 13 or 14, wherein   The joining method according to claim 14, wherein, in the friction stir step, friction stir is performed by relatively moving the rotary tool outside the groove. A step of preparing a first metal member and a second metal member made of an aluminum alloy having different areas of the superimposed surfaces to be superimposed,
When forming a superposed portion by superimposing the superposed surfaces of the first metal member and the second metal member, a superposing step of sandwiching a copper foil or a copper alloy foil between the superposed surfaces,
After the superimposing step, the first metal member and the second metal member are heated to 510 ° C. or more while being pressed, and a diffusion bonding step of diffusion bonding the first metal member and the second metal member,
After the diffusion bonding step, a stirring pin of a rotating tool is inserted from an inner corner formed by the first metal member and the second metal member, and a friction stir step of friction-stirring the overlapped portion over the entire circumference, A joining method comprising: Before the superimposing step, the method includes a groove forming step of providing a groove along at least one peripheral edge of the superposed surface of the first metal member and the superposed surface of the second metal member,
The bonding method according to claim 17, wherein in the overlapping step, the copper foil or the copper alloy foil is sandwiched inside the concave groove in the overlapping surface.

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