Method for joining dissimilar metal materials

Abstract

To provide a method of joining dissimilar metal material capable of solving such a problem in the conventional joining method that security of a joint space is difficult, a joint object is restricted to a large-size component and a working time increases because half surfaces of plate material are joined in order when joining both surfaces of the plate material.SOLUTION: A method of joining plate materials 10, 20, 60 made of dissimilar metal material to each other by using two pieces of rotary tools T1, T2 includes a first process of fixing the plate materials 10, 20, 60 in such a state that the plate materials made of dissimilar metal material are brought into contact with each other, a second process of pressurizing the surrounding of an insertion scheduled position of two lines of the rotary tools T1, T2 on surfaces of the plate materials 10, 20, and a third process of arranging two lines of rotary tools T1, T2 via the plate materials 10, 20, 60 so that respective rotary axes C1, C2 get to the same straight line and inserting tips of two lines of the rotary tools T1, T2 into the plate materials 10, 20 at the same time while two lines of the rotary tools T1, T2 rotate in the opposite direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for joining dissimilar metal materials, in which two or more types of dissimilar metal materials (plate materials) are integrated by friction stir spot joining (friction stir spot welding).

Background Art

[0002] In the joining of dissimilar metal materials, methods of joining the joined members in a solid state, such as friction stir joining in which a rotating tool is linearly moved for joining and ultrasonic joining in which ultrasonic waves are used for joining, are known to exhibit excellent strength and properties because it is easy to control the thickness of intermetallic compounds between non-metallic materials that act as binders.

[0003] Friction stir joining and ultrasonic joining are the same solid-state joining, but the joined members targeted for ultrasonic joining are limited to materials with a thin thickness such as foils. Therefore, friction stir joining has fewer restrictions on the size and joining direction of the joined members, and the time required for joining is also shortened.

[0004] However, even in friction stir joining, it is difficult to join materials with a thick thickness of the joined members, such as plates with a thickness of 10 mm or more, and there are problems such as a decrease in joining strength and a shortening of tool life. As a method for solving these problems, friction stir spot joining (friction stir spot welding) in which joining is performed from both sides of the member has been proposed. Such a joining method has a major feature that the amount of heat generation increases by inserting the tool from both sides (see Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

[0006] However, the joining methods disclosed in Patent Documents 1 to 3 made it difficult to secure sufficient space when joining plates of dissimilar metal materials, and the objects to be joined were limited to relatively large parts. Furthermore, when joining both sides of a plate, the plates had to be joined one side at a time, which increased the overall processing time. As a result, there was a problem that the required joint strength could not be obtained because the joining positions on the front and back surfaces of the plate, especially the center, were spaced apart. In addition, when joining the plates one side at a time, the first joint on one side would peel off due to the heat and pressure generated when joining the opposite side at the same position.

[0007] Therefore, the present invention provides a method for joining dissimilar metal materials that minimizes the joining space between the dissimilar metal sheet materials. Furthermore, it enables the rapid production of joined sheet materials compared to other joining methods. At the same time, it aims to provide a method for joining dissimilar metal materials that also reduces the area required for joining in the component (sheet material). [Means for solving the problem]

[0008] The present invention provides a method for joining dissimilar metal materials using two rotary tools, comprising: a first step of fixing the surfaces of the dissimilar metal plates in contact with each other; a second step of applying pressure to the areas around the intended insertion points of the two rotary tools on the surfaces of the plates; and a third step of simultaneously inserting the tips of the two rotary tools into the plates while arranging them so that their respective axes of rotation are on the same line and rotating them in opposite directions. These dissimilar metal plates may be formed from at least three or more plates. The rotary tools may also be made of nickel alloy. [Effects of the Invention]

[0009] The present invention provides a method for joining dissimilar metal materials, in which the rotation axes of the two rotary tools are on the same straight line, and joining is possible even if the joining points on the front and back sides of the dissimilar metal sheet overlap, thus minimizing the joining space of the parts (sheet materials).

[0010] Furthermore, the present invention's method for joining dissimilar metal materials involves inserting a rotary tool from both sides of the dissimilar metal plate material, allowing for simultaneous joining at two points during the joining process.

[0011] In other words, because two joining positions on the same central axis of the plate material heat up simultaneously, joining can be done in a short time, allowing for faster production of joined products compared to other joining methods. At the same time, it has the effect of reducing the area required for joining on the part (plate material). Furthermore, since the method for joining dissimilar metal materials of the present invention applies pressure and heat to both sides of the part (plate material) simultaneously, it also has the effect of suppressing the phenomenon in which the joint surface peels off due to the heat and pressure generated when joining the opposite side at the same position, which occurs when joining the same part on each side. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view showing the first step of the joining method of the present invention. [Figure 2] This is a schematic cross-sectional view showing the second step of the joining method of the present invention. [Figure 3] This is a schematic cross-sectional view showing the third step of the joining method of the present invention. [Figure 4] This is a schematic plan view of jointed product 2. [Figure 5] This is a schematic front view of jointed product 2. [Figure 6] Figure 4 is an enlarged view of the joint 11E shown in Figure 4. [Figure 7] This is a cross-sectional view along line XX shown in Figure 6. [Modes for carrying out the invention]

[0013] An embodiment of the method for joining dissimilar metal materials of the present invention will be described with reference to the drawings. A schematic cross-sectional view showing the first step in the method for joining dissimilar metal materials of the present invention is shown in FIG. 1, a schematic cross-sectional view showing the second step is shown in FIG. 2, and a schematic cross-sectional view showing the third step is shown in FIG. 3, respectively.

[0014] First, as shown in FIG. 1, two second plate members 60 are sandwiched between two plate members (first and third plate members 10, 20) using a jig or the like of a joining device (not shown), and the surfaces of the plate materials made of dissimilar metals (first to third plate members 10, 20, 60) are fixed in a state of being in contact with each other (first step).

[0015] Thereafter, the periphery of the planned insertion positions of the two rotary tools T1, T2 arranged to face the surfaces of the first to third plate members 10, 20, 60 is pressurized by the pressurizing jigs P1, P2 (second step). At the same time, the two rotary tools T1, T2 are individually rotated from the directions of the two first and third plate members 10, 20 while approaching the first and third plate members 10, 20.

[0016] At this time, as shown in FIG. 2, the respective rotation axes C1, C2 of the rotary tools T1, T2 are arranged so as to be on the same straight line in the thickness direction (left - right direction in the drawing) of the second plate member 60 and the two first and third plate members 10, 20. At the same time, the rotary tool T1 and the rotary tool T2 are rotated in opposite directions (in a reverse rotation relationship with each other).

[0017] After the rotational speeds of the rotary tools T1, T2 reach a predetermined state, as shown in FIG. 3, while pressurizing the surfaces of the first and third plate members 10, 20 by the pressurizing jigs P1, P2, the tips of the rotary tools T1, T2 are simultaneously inserted into the first and third plate members 10, 20 (third step). By separating the rotary tools T1, T2 from the first and third plate members 10, 20, the joining process of the second plate member 60 and the two first and third plate members 10, 20 is completed.

[0018] In this embodiment, as shown in FIG. 3, when the tip positions of the rotary tools T1 and T2 in the joining process are within the first and third plate-like members 10 and 20, the completion of the joining process is determined. However, when three or more plate materials are used in the joining, the tip position (insertion depth of the tool tip) of the rotary tool in the joining process is not particularly limited.

[0019] Next, the joined product produced using the joining method of the present invention described above will be described with reference to the drawings. A schematic plan view of the joined product 2 produced using the joining method of the present invention is shown in FIG. 4, a schematic front view is shown in FIG. 5, an enlarged view of the joint portion 11 at the center of the joined product 2 shown in FIG. 4 is shown in FIG. 6, and an X-X cross-sectional view of the joint portion (recess) 11E at the center of the joined product 2 shown in FIG. 6 is shown in FIG. 7, respectively.

[0020] The joined product 2 produced using the joining method of the present invention described above is composed of two first and third plate-like members 11 and 21 and one second plate-like member 61, as shown in FIGS. 4 and 5. The first and third plate-like members 11 and 21 and the one second plate-like member 61 are made of different metals from each other.

[0021] A part (end portion) of the second plate-like member 61 is sandwiched between the two first and third plate-like members 11 and 21, as shown in FIG. 5, and the plate-like members are joined to each other by friction stir point joining (friction stir spot joining) at the sandwiched portion.

[0022] A joint portion (recess) 11E is formed on the surface of the first plate-like member 11, as shown in FIG. 4, and a recess 21E is also formed on the surface of the third plate-like member 21, as shown in FIG. 7. These recesses 11E and 21E are both formed concentrically, as shown in FIG. 7, have a raised portion on the outer peripheral portion, and crater-shaped recesses 11E and 21E are formed toward the center side.

[0023] Below the bottom surface 11S of the recess 11E of the first plate-shaped member 11, the first plate-shaped member 11 and the second plate-shaped member 61 are fixed to each other, as shown in Figure 7. Also, below the bottom surface 21S of the recess 21E of the third plate-shaped member 21, the third plate-shaped member 21 and the second plate-shaped member 61 are fixed to each other.

[0024] In other words, the bottom surface 11S of the recess 11E of the first plate-like member 11 does not reach the surface of the second plate-like member 61, as shown in Figure 7, and the first plate-like member 11 and the second plate-like member 61 are joined together while maintaining a predetermined distance d11 from each other.

[0025] Similarly, as shown in Figure 7, the bottom surface 21S of the recess 21E of the third plate-like member 21 does not reach the surface of the second plate-like member 61, and the third plate-like member 21 and the second plate-like member 61 are joined together while maintaining a predetermined distance d21 from each other.

[0026] Furthermore, the center of the recess 11E in the first plate-like member 11 and the center of the recess 21E in the third plate-like member 21 are the same. In other words, these two recesses 11E and 21E are formed on the same central axis C3 in the thickness direction (up and down direction in the drawing) of the joined product 2.

[0027] In this embodiment, as shown in Figure 7, the first plate-like member 11 and the second plate-like member 61 are joined while maintaining a gap d11, and the third plate-like member 21 and the second plate-like member 61 are joined while maintaining a gap d21. However, if there are three or more plate materials used in the joining method of the present invention, the spacing of the joint portions (recesses) of each plate material at the time of completion of joining is not particularly limited. [Explanation of symbols]

[0028] 1,2 Joined products 10,11 First plate-like member 11E, 21E recess 11S, 21S Bottom surface of the recess 20,21 Third plate-like member 60,61 Second plate-like member d11,d21 interval C1, C2 Rotation axis of rotary tool C3 Center (axis) of the recess T1, T2 rotary tools P1, P2 Pressurizing fixture

Claims

1. A method for joining dissimilar metal plates using two rotary tools, comprising: a first step of fixing the surfaces of the dissimilar metal plates in contact with each other; a second step of applying pressure to the area around the positions on the surface of the plates where the two rotary tools are to be inserted; and a third step of simultaneously inserting the tips of the two rotary tools into the plates while arranging the two rotary tools via the plates so that their respective axes of rotation are on the same straight line and rotating them so that their rotation directions are opposite to each other.

2. The method for joining dissimilar metal materials according to claim 1, characterized in that the aforementioned dissimilar metal plate material is formed from at least three or more plate materials.

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