JP7035892B2 - A friction stir welding device and a method for manufacturing a friction stir welding body using the friction stir welding device. - Google Patents

Description

The present invention relates to a friction stir welding apparatus and a method for manufacturing a friction stir welding body using the friction stir welding apparatus.

Conventionally, as described in Patent Document 1, a friction stir welding method using a tool having a shoulder that comes into contact with the surface of the member to be welded and a probe that is pushed into the member to be welded is known.

Japanese Unexamined Patent Publication No. 2012-082667

When a member to be welded having a relatively thick plate thickness is friction-stir welded, a shoulder as described in Patent Document 1 prevents the pressure on the member to be welded from decreasing. On the other hand, when the plate thickness of the member to be joined is thin, the heat capacity and rigidity of the member to be joined become small. Therefore, when a member to be welded with a relatively thin plate thickness is friction-stir welded, the member to be welded may be overheated or deformed due to friction between the shoulder and the member to be welded, and the member to be welded may be damaged. be.

The present invention has been created in view of the above points, and an object thereof is to increase the strength of a friction stir weld while preventing damage to the member to be welded even if the member to be welded has a thin plate thickness. It is an object of the present invention to provide an improved friction stir welding apparatus and a method for manufacturing a friction stir welding body.

The friction stir welding device of the present invention joins the first member (11) and the second member (12). The first member and the second member are formed in a plate shape, are in contact with each other, and have a contact point (Pa). The friction stir welding device includes a tool (20) and a control unit (40).

The tool is formed in a rod shape, is rotatable about a tool axis (Ot), is able to translate, and has a probe surface. The probe surface faces the first member and the second member and is formed so as to be a curved surface, and includes the center of curvature (Po) inside the tool.

In the control unit, the tool rotates while the tool axis is located closer to the contact point on the retreating side (Rs), which is the side where the tool rotation direction (Dr) is opposite to the tool movement direction (Dm). The tool is controlled so that the probe surface rubs against the first member and the second member.

By locating the tool shaft on the retreating side, the temperature around the joint portion of the first member and the second member can be made uniform. As a result, the plastic flow of both the first member and the second member is promoted, and the strength of the joint portion of the first member and the second member is improved. Further, since the probe surface is formed so that the center of curvature is located inside the tool, the parts other than the joints of the first member and the second member are non-contact, so that the first member and the second member Friction resistance other than the joint is reduced. Since the frictional resistance is reduced, overheating and deformation of the first member and the second member are prevented, and damage to the first member and the second member is prevented.

The present invention is also provided as a method for manufacturing a friction stir welder using the friction stir welder. The method for manufacturing a friction stir welding body includes a tool position adjusting step (S12) and a friction stir welding step (S13). In the tool position adjusting step, the tool is moved so that the tool axis is located on the retreating side of the contact point. In the friction stir welding step, the probe surface is rubbed against the first member and the second member while rotating the tool. This has the same effect as the friction stir welding device.

The block diagram of the friction stir welding apparatus by one Embodiment. Top view of the friction stir welding apparatus according to one embodiment. The cross-sectional view for demonstrating the offset amount of the friction stir welding apparatus by one Embodiment. A cross-sectional view for explaining the temperature distribution of the first member and the second member when the first member and the second member are friction stir welded by using the friction stir welding apparatus according to one embodiment. A side view of a friction stir welder when the first member and the second member are friction stir welded by using the friction stir welding apparatus according to one embodiment. The flowchart for demonstrating the manufacturing method of the friction stir welding according to one Embodiment. The block diagram of the friction stir welding apparatus by another embodiment. The block diagram of the friction stir welding apparatus by another embodiment. FIG. 3 is a side view of a friction stir welded body when the first member and the second member are friction stir welded by using the friction stir welding apparatus according to another embodiment. An enlarged view for explaining a gap generated when the members to be joined in the comparative example are butted against each other.

Hereinafter, the friction stir welding apparatus according to the embodiment will be described with reference to the drawings. In the description of the plurality of embodiments, substantially the same configuration will be described with the same reference numerals. The present embodiment includes a plurality of embodiments. The friction stir welding device of the present embodiment is used for friction stir welding of the first member 11 and the second member 12. First, the first member 11 and the second member 12 as the members to be joined will be described.

As shown in FIG. 1, the first member 11 and the second member 12 are in contact with each other. The point where the first member 11 and the second member 12 are in contact is defined as a contact point Pa.

Further, the first member 11 and the second member 12 are formed in a plate shape. The plate thickness of the first member 11 is defined as the first plate thickness T1. The plate thickness of the second member 12 is defined as the second plate thickness T2. The first plate thickness T1 and the second plate thickness T2 are about 0.1 mm to 0.5 mm. The first member 11 is formed so that the first plate thickness T1 is the same as the second plate thickness T2, that is, T1 = T2. In this specification, "same" and "=" include a common sense error range. Further, in the figure, the thicknesses of the first member 11 and the second member 12 are exaggerated.

Further, the first member 11 is made of the same material as the second member 12. Both the first member 11 and the second member 12 are made of aluminum (Al). The first member 11 and the second member 12 may be made of iron (Fe), copper (Cu), or the like.

(One embodiment)
The friction stir welding device 51 includes a tool 20, a base 30 as a support portion, and a control portion 40.

The tool 20 is formed in a rod shape and has a circular cross section in the radial direction of the tool 20. Further, the tool 20 can rotate around the tool axis Ot extending in the axial direction and can translate.

As shown in FIG. 2, the rotation direction of the tool 20 is defined as the tool rotation direction Dr. The moving direction of the tool 20 is defined as the tool moving direction Dm. The side where the tool rotation direction Dr is opposite to the tool movement direction Dm is defined as the retreating side Rs. The side where the tool rotation direction Dr coincides with the tool movement direction Dm is defined as the advancing side As.

Returning to FIG. 1, the tool 20 is made of tool steel or the like and has a probe 21 at its tip. The probe 21 includes a probe surface 22. The probe surface 22 faces the first member 11 and the second member 12, and is formed in a curved surface shape. The local bending of the probe surface 22 can be approximated to a circle.

Let the radius of this approximate circle be the radius of curvature SR. The center of the circle having the radius of curvature SR is defined as the center of curvature Po. The probe surface 22 is formed so that the center of curvature Po is located inside the probe 21, and is formed so as to have a convex curved surface toward the first member 11 and the second member 12. In one embodiment, the probe surface 22 is formed in a spherical shape, and the radius of curvature SR is constant.

The base 30 is formed in a plate shape and is provided on the opposite side of the tool 20. The base 30 can come into contact with the first member 11 and the second member 12 to support the first member 11 and the second member 12. When the first member 11 and the second member 12 and the tool 20 rub against each other, the base 30 supports the force acting on the first member 11 and the second member 12 by the tool 20.

The control unit 40 can control the rotation and translation of the tool 20. The control unit 40 is mainly composed of a microcomputer, and includes a CPU, a readable non-temporary tangible recording medium, a ROM, an I / O, a bus line connecting these configurations, and the like. Each process of the control unit 40 may be a software process by executing a program stored in advance in a substantive memory device such as a ROM by the CPU, or may be a hardware process by a dedicated electronic circuit. good.

Further, in the control unit 40, when the first member 11 and the second member 12 are friction-stir welded, the tool shaft Ot is located at the retreating side Rs rather than the contact point Pa, and the first member 11 and the second member 12 are joined. The tool 20 is controlled so that the probe surface 22 and the probe surface 22 rub against each other. The distance from the contact point Pa to the tool axis Ot is defined as the offset amount Wf.

As shown in FIG. 3, when the first member 11 and the second member 12 are friction-stir welded, the control unit 40 satisfies the following relational expressions (1-1)-(1-6) while the offset amount Wf is satisfied. The tool 20 is controlled so as to push the tool 20 into the first member 11 or the second member 12. In the cross-sectional view, the tool 20 is shown in white in order to clarify the relationship between the first member 11, the second member 12, and the tool 20.

The depth at which the tool 20 is pushed into the first member 11 or the second member 12 is defined as the pushing amount H. The end point at the boundary portion when the probe surface 22 is pushed into the first member 11 and the second member 12 is defined as the boundary point Pb. The distance from the tool axis Ot to the boundary point Pb is defined as the insertion width Wb. The pushing amount H is the distance from the surface of the first member 11 or the second member 12 to the tip of the probe 21 when the probe surface 22 is pushed into the first member 11 and the second member 12. Further, the pushing amount H may be set in advance by an experiment, a simulation, or the like, or may be adjusted for each friction stir welding. Further, θ in the relational expression (1-4) is an angle expressed in degrees or radians.

0 <H <T1 ... (1-1)
0 <H <T2 ... (1-2)
Hz = SR-H ・ ・ ・ (1-3)
θ = arccos (Hz / SR) ・ ・ ・ (1-4)
Wb = SR × sinθ ・ ・ ・ (1-5)
0 <Wf <Wb ... (1-6)

At the portion of the advancing side As, since the speed of the tool is relatively high, frictional heat is likely to be generated, and the temperature of the member to be joined is likely to rise. On the other hand, in the portion of the retreating side Rs, since the speed of the tool is relatively slow, frictional heat is less likely to be generated than in the portion of the advancing side As, and the temperature of the member to be joined rises more than in the portion of the advancing side As. Hateful. Therefore, at the site of the retreating side Rs, plastic flow is less likely to occur, stirring is less likely to occur, and the joining strength of the joined body is reduced.

Therefore, as shown in FIG. 4, by locating the tool axis Ot on the retreating side Rs rather than the contact point Pa, the temperature around the joint portion of the first member 11 and the second member 12 can be made uniform. .. As a result, the plastic flow of both the first member 11 and the second member 12 is promoted, and the strength of the joint portion of the first member 11 and the second member 12 is improved. In the figure, the range C in which the temperature at the time of friction stir welding is relatively high is described by a dot pattern. The contact surface B of the first member 11 and the second member 12 is shown by a broken line.

On the other hand, in Patent Document 1, in friction stir welding of members to be joined having different plate thicknesses, there is a tool provided with a shoulder formed so as to have a convex curved surface toward the member to be joined and a probe connected to the shoulder. Are listed. Further, as Patent Document 2, Japanese Patent Application Laid-Open No. 2007-083242 describes that in friction stir welding of dissimilar materials, friction stir welding is performed while the center of the tool having a shoulder and a probe is located on the soft metal side. There is. As Patent Document 3, Japanese Patent Application Laid-Open No. 2013-248647 describes that friction stir welding is performed while the center of the tool having a shoulder and a probe is located on the retreating side.

However, when a member to be welded having a relatively thin plate thickness is friction-stir welded as in the configuration of Patent Document 1-3, the member to be welded may be overheated or deformed due to friction between the shoulder and the member to be welded. there were. In addition, when a tool is located on the soft metal side or the retreating side in friction stir welding of dissimilar materials and a member to be welded with a relatively thin plate thickness is bonded even if friction stir welding is performed, the shoulder and the bonded member are bonded. Friction with the member may damage the member to be welded.

Therefore, in the friction stir welding device 51 of the present embodiment, the probe surface 22 is formed so that the center of curvature Po is located inside the probe 21 without a shoulder. As a result, the parts other than the joints of the first member 11 and the second member 12 become non-contact, and the frictional resistance other than the joints of the first member 11 and the second member 12 is reduced. Since the frictional resistance is reduced, overheating and deformation of the first member 11 and the second member 12 are prevented, and damage to the first member 11 and the second member 12 is prevented.

By the way, as described in Japanese Patent Application Laid-Open No. 2007-136544 or Japanese Patent Application Laid-Open No. 2015-024418, it is known that members to be welded are butted and friction stir welded. In JP-A-2015-024418, it is necessary to provide a convex portion in the plate thickness direction, and burrs are likely to occur after friction stir welding. Therefore, it is necessary to remove burrs. Further, in Japanese Patent Application Laid-Open No. 2015-024418, it is necessary to remove the remaining convex portion after friction stir welding, and it is necessary to perform post-treatment.

Further, as shown in FIG. 10, when two members to be joined 90 as a comparative example are butted, a minute gap 91 is formed between the members to be joined 90 due to the shape of the waviness or the butted surface of the members to be joined 90. Will be done. Therefore, the pressure to be joined by friction stir welding may cause the member to be joined 90 to be deformed toward the void 91, and the pressure may decrease. When the pressure decreases, the amount of heat input to the joint portion of the member to be joined 90 becomes small, and the member 90 to be joined is less likely to be agitated. Insufficient stirring of the member to be joined 90 may reduce the strength of the friction stir weld. Further, when the plate thickness of the member to be joined 90 is relatively thin, even if the member to be joined 90 is deformed toward the gap 91, the gap 91 is not filled and the pressure tends to decrease. Therefore, in the friction stir welding device 51 of the present embodiment, the arrangement of the first member 11 and the second member 12 is changed as follows, and it is possible to further improve the strength of the friction stir welding body.

The facing surface of the first member 11 facing the second member 12 is referred to as a first facing surface 111. The end portion of the first member 11 on the second member 12 side is referred to as the first end portion 112. The end portion of the second member 12 on the first member 11 side is referred to as the second end portion 122. The end point of the first end portion 112 on the second member 12 side is referred to as the first end point P1. The end point of the second end portion 122 on the tool 20 side is referred to as the second end point P2.

Returning to FIG. 1, the first member 11 is provided so that the first end portion 112 is located on the tool 20 side and is located on the retreating side Rs with respect to the contact point Pa, and the second member 12 is provided. It is provided so as to overlap with. The intersection of the first facing surface 111 and the second end point P2 is the contact point Pa. The first end 112 is non-contact with the base 30.

By superimposing the first member 11 on the second member 12, excess meat is formed. Therefore, in the case of friction stir welding of the first member 11 and the second member 12 having a relatively thin plate thickness, the gap can be filled when the first member 11 and the second member 12 are deformed toward the gap. Since the voids can be filled, the pressure in the friction stir welding can be maintained. Therefore, the first member 11 and the second member 12 are easily agitated, and the strength of the friction stir weld is further improved.

Further, the first member 11 is provided so that the first end point P1 is located on the tool axis Ot. As a result, as shown in FIG. 5, the surplus portion does not become excessive, only the trace M of the probe surface 22 remains, and burrs generated when the first member 11 and the second member 12 are deformed are generated. Is suppressed. Therefore, it is not necessary to remove burrs and the like, post-treatment is not required, and it becomes easy to manufacture a friction stir weld.

Next, a method of manufacturing a friction stir welder using the friction stir welder 51 of the present embodiment will be described with reference to the flowchart of FIG. Hereinafter, in the description of the flowchart, "S" represents a step. A method for manufacturing a friction stir welding body using a friction stir welding apparatus 51 includes a member setting process for a member to be joined, a tool position adjusting step, and a friction stir welding step.

In the process of setting the member to be joined in S11, the first member 11 and the second member 12 are arranged on the base 30. Further, the first member 11 is superposed on the second member 12 so that the first end portion 112 is located on the tool 20 side and is located on the retreating side Rs with respect to the contact point Pa.

In the tool position adjusting step of S12, the control unit 40 moves the tool 20 so that the tool axis Ot is located on the retreating side Rs rather than the contact point Pa. At this time, the position of the tool 20 is adjusted so that the relational expressions (1-1)-(1-6) are satisfied.

In the friction stir welding step of S13, the tool 20 is moved so that the probe surface 22 comes into contact with the first member 11 and the second member 12 while satisfying the relational expressions (1-1)-(1-6). Then, while rotating the tool 20, the tool 20 is moved so that the probe surface 22 passes through the contact point Pa. The rotation speed and moving speed of the tool 20 are appropriately adjusted depending on the material of the first member 11, the material of the second member 12, the first plate thickness T1 or the second plate thickness T2, and the like.

When the tool 20 moves while rotating, the probe surface 22 rubs against the first member 11 and the second member 12. At this time, the first member 11 and the second member 12 are agitated, and the first member 11 and the second member 12 are joined. By the method of manufacturing the friction stir welding using the friction stir welding device 51, the first member 11 and the second member 12 are prevented from being damaged, and the friction stir welding body in which the strength of the joint portion is improved is completed. In addition, it is not necessary to remove burrs and the like, post-treatment is not required, and it becomes easy to manufacture a friction stir weld.

(Other embodiments)
[1] As shown in FIG. 7, in the first member 11 or the tool 20, the tool axis Ot is located on the advancing side As from the first end point P1 and on the retreating side Rs from the contact point Pa. May be provided. The first member 11 or the tool 20 may be provided so that the tool shaft Ot is located between the first endpoint P1 and the contact point Pa. Even in such a form, the same effect as when the first end point P1 is located on the tool axis Ot is obtained.

[2] As shown in FIGS. 8 and 9, the first member 11 may be formed so that the first plate thickness T1 is different from the second plate thickness T2. In the figure, the case where the first plate thickness T1 is smaller than the second plate thickness T2 is described. At this time, the friction stir welding device 51 further includes a spacer 45 as a plate thickness adjusting portion.

The spacer 45 is provided between the first member 11 and the base 30. The plate thickness of the spacer 45 is defined as the adjusted thickness Ts. The spacer 45 is formed so that the sum of the first plate thickness T1 and the adjusted thickness Ts coincides with the second plate thickness T2, that is, T1 + Ts = T2. Even in such a form, the same effect as described above is obtained.

[3] The first member 11 may be made of a material different from that of the second member 12. The first member 11 is made of, for example, aluminum. The second member 12 is made of, for example, iron. The first member 11 is provided so that the first end portion 112 is located on the tool 20 side and is located on the retreating side Rs with respect to the contact point Pa. Even in such a form, the same effect as described above is obtained.

When the first member 11 and the second member 12 are made of different materials, the first member 11 made of aluminum having a melting point lower than the melting point of iron is superposed on the second member 12. That is, the material having a low melting point is layered on the material having a high melting point. By superimposing a material with a low melting point on a material with a high melting point, the true contact area of the material with a high melting point becomes smaller, and the pressure applied microscopically increases. Therefore, the oxide film of the material having a high melting point is easily removed, the material having a high melting point is easily softened, and the plastic flow is easy.

[4] The probe surface is not limited to a spherical shape, and may be formed so as to be a curved surface such as a cylindrical surface.

As described above, the present invention is not limited to such an embodiment, and can be implemented in various forms without departing from the spirit of the invention.

11 ... 1st member, 12 ... 2nd member,
20 ... Tools,
40 ... Control unit,
51 ... Friction stir welding device,
Pa ・ ・ ・ Contact point,
Ot ・ ・ ・ Tool axis,
Dr ・ ・ ・ Tool rotation direction, Dm ・ ・ ・ Tool movement direction,
Rs ・ ・ ・ Retreating side.

Claims (7)

A friction stir welding device (51) that joins a first member (11) and a second member (12) that are formed in a plate shape and are in contact with each other and have a contact point (Pa).
It is formed in a rod shape, can rotate around the tool axis (Ot), and can be translated, and is formed so as to face the first member and the second member and form a curved surface, and has a center of curvature (Po). ) Inside the tool (20) having the probe surface (22) and
The tool rotates while the tool axis is positioned from the contact point on the retreating side (Rs) on which the rotation direction (Dr) of the tool is opposite to the movement direction (Dm) of the tool. While the control unit (40) that controls the tool so that the first member and the second member and the probe surface rub against each other,
A friction stir welding device. The first member is claimed that the end portion (112) of the first member is located on the tool side and is located on the retreating side of the contact point and is in contact with the second member. Item 1. The friction stir welding apparatus according to Item 1. The end point (P1) of the end portion (112) of the first member is located on the tool axis, or the tool is located between the end point (P1) of the end portion (112) of the first member and the contact point. The friction stir welding apparatus according to claim 2, wherein the shaft is located. The friction stir welding apparatus according to any one of claims 1 to 3, further comprising a support portion (30) provided on the opposite side of the tool and capable of supporting the first member or the second member. .. The friction stir welding device according to any one of claims 1 to 4, wherein the first member is made of the same material as the second member. The first member is made of a material different from that of the second member, has a melting point lower than that of the second member, the end portion (112) of the first member is located on the tool side, and the first member is described. The friction stir welding apparatus according to claim 1, which is located on the retreating side of the contact point and is in contact with the second member. A method for manufacturing a friction stir weld, which is formed in a plate shape and is formed by joining a first member (11) and a second member (12) which are in contact with each other and have a contact point (Pa).
It is formed in a rod shape, can rotate around the tool axis (Ot), and can be translated, and is formed so as to face the first member and the second member and form a curved surface, and has a center of curvature (Po). The tool axis is on the retreating side (Rs) on which the rotation direction (Dr) of the tool (20) having the probe surface (22) including the inside is opposite to the movement direction (Dm) of the tool. The tool position adjusting step (S12) for moving the tool so that the tool is located closer to the contact point.
A friction stir welding step (S13) in which the first member and the second member are rubbed against the probe surface while rotating the tool.
A method for manufacturing a friction stir weld.

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