JP2011011239A - Lid joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lid joining method having good workability without leaving a through hole of a rotary tool at a surface of a lid plate.SOLUTION: In the lid joining method, the lid plate 3 for covering an opening of a cylindrical body 2 is mounted at the end surface 4b of the cylindrical body 2, the rotary tool G is pushed in from the surface 3a of the lid plate 3, and the cylindrical body 2 and the lid plate 3 are fixed by friction stir welding. The lid joining method includes a joining step, in which an extension part 3d extended outside the outer circumferential surface 5 of the cylindrical body 2 is arranged at the lid plate 3 and an extraction position EM1 for separating a stirring pin G2 is set at the extension part 3d and the stirring pin G2 is inserted from the surface 3a of the lid plate 3, the cylindrical body 2 and the lid plate 3 are fixed by the friction stir welding, and the stirring pin G2 is separated from the lid plate 3 at the extraction position EM1 through gradually reducing insertion amount while moving the rotary tool G; and a cutting step for cutting the extraction part 3d.

Description

  The present invention relates to a lid joining method for joining a lid to a cylindrical body by friction stirring.

  Friction stir welding (FSW = Friction Stir Welding) is known as a method for joining metal members. Friction stir welding is a technique in which metal members are fixed to each other by causing the metal at the abutting portion to plastically flow by frictional heat between the rotating tool and the metal member by moving the rotating tool along the abutting portion while rotating the rotating tool. Phase joining is performed. Patent Document 1 discloses a technique in which, after metal members are superposed on each other, a rotating tool is inserted from the surface side of the metal members and friction stir welding is performed on the interface between the metal members.

  For example, a conventional joining method can be used when joining a cover plate covering the opening of the tubular body to a tubular body having a tubular shape. After placing the cover plate on the end face on the opening side of the cylindrical body, a rotary tool is pushed in from the surface side of the cover board, and friction stir welding is performed on the interface between the end face of the cylindrical body and the back surface of the cover plate. Can be integrally molded.

  However, according to the conventional joining method, the rotary tool is pulled out vertically from the friction stirring end position in the vertical direction with respect to the cover plate, so that a hole having a shape equivalent to the shape of the stirring pin is formed on the surface of the cover plate. The If the hole remains in the cover plate, not only the airtightness and watertightness are lowered, but also the quality of the product is lowered. Further, if a hole remains in the cover plate, it is not preferable in terms of the design of the product.

  Therefore, in Patent Document 2, an extending portion (discarded meat portion) is provided in advance on the outer side of the joint portion for performing friction stir welding, and after the friction stir welding, the rotating tool is moved to the extending portion and the rotating tool is pulled out. Later, a technique for cutting out the extended portion is disclosed. According to such a joining method, the loophole of the rotary tool does not remain in the joined product.

Japanese Patent No. 3409673 (FIG. 5 etc.) Japanese Patent No. 3262757 (FIG. 2 etc.)

  However, when joining the cover plate covering the opening of the cylindrical body, as in Patent Document 2, if an extension portion is provided on the outer edge of the cover plate and friction stir welding is performed, the end face of the cylindrical body and the cover plate When the rotating tool is moved from the interface formed with the back surface to the extending portion side, there is a problem that the extending portion (cover plate) is broken by the pressing force of the rotating tool. If the rotary tool breaks through the cover plate, the tip of the rotary tool may come into contact with the cylindrical body, and the joined product may be wrinkled.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a lid joining method with good workability without leaving a through hole of a rotating tool on the surface of the lid plate.

  As a means for solving the above-mentioned problems, the present invention provides a rotating tool that is placed on the end face of a cylindrical body and covers a cover plate that covers at least a part of the opening of the cylindrical body. Is a lid joining method in which the cylindrical body and the lid plate are fixed by friction stir welding while the tip of the stirring pin of the rotating tool is positioned near the interface between the end surface and the back surface of the lid plate. The cover plate is provided with an extended portion extending outward from the outer peripheral surface of the cylindrical body, and a set position for removing the stirring pin is set in the extended portion, and the surface of the cover plate The stirrer pin is inserted, and the cylindrical body and the lid plate are fixed by friction stir welding, and then the rotating tool is moved from the interface to the extraction position while gradually reducing the amount of insertion, and the stirrer pin is moved. In the extraction position, And performing a bonding step of separating from the plate, and a cutting step of excising said extended portion, a.

  According to such a lid joining method, an extension part is set on the lid plate to set an extraction position for removing the stirring pin of the rotary tool, and after the friction stir welding, the extension part is cut off to rotate the joined product. Tool loopholes do not remain. Further, after the friction stir welding, the amount of insertion is gradually reduced while moving the rotary tool from the interface to the extraction position, so that the rotary tool does not break through the lid plate.

  Further, an insertion position for inserting the stirring pin into the extended portion is set, and in the joining step, when inserting the rotary tool, the insertion amount of the rotary tool is gradually increased while the interface direction from the insertion position is changed to the interface direction. It is preferable to move the rotary tool.

  According to this lid joining method, when inserting the rotary tool, it is possible to prevent the tip of the stirring pin from penetrating through the lid plate before reaching the interface.

  Moreover, it is preferable that after fixing the said cylindrical body and the said cover plate, the surface of the said cover plate is excised by predetermined thickness. According to such a lid joining method, it is possible to prevent burrs and the like formed by friction stirring from remaining on the surface of the lid plate.

  Moreover, it is preferable to perform friction stir welding in a state where the tip of the stirring pin is in contact with the end surface of the cylindrical body. According to this lid joining method, the interface can be reliably joined.

  Moreover, the end surface of the said cylindrical body is equipped with the 2nd end surface which has a level | step difference with respect to a 1st end surface and a 1st end surface, and covers either one of the said 1st end surface side and the said 2nd end surface side. It is preferable to mount the lid plate as described above. According to such a lid joining method, a product having a step on the end face of the cylindrical body and partially covering the opening can be formed.

  According to the present invention, since the workability is good, it is possible to form a product in which the joined product is not easily wrinkled, and the punched hole of the rotary tool does not remain on the surface of the lid plate.

It is the disassembled perspective view which showed the structure which concerns on 1st embodiment. It is the figure which showed the structure which concerns on 1st embodiment, Comprising: (a) is a top view, (b) is II sectional drawing of (a). It is the side view which showed the rotary tool which concerns on 1st embodiment. It is the top view which showed the joining process which concerns on 1st embodiment, Comprising: (a) is an insertion position, (b) is an intermediate position, (c) shows an extraction position. It is sectional drawing which showed the joining process which concerns on 1st embodiment, Comprising: (a) is an insertion position, (b) is an intermediate position, (c) shows an extraction position. It is the figure which showed the cutting process which concerns on 1st embodiment, Comprising: (a) is a top view, (b) is II-II sectional drawing of (a). It is the figure which showed the structure which concerns on 2nd embodiment, Comprising: (a) is a disassembled perspective view, (b) is sectional drawing. It is the figure which showed the joining process which concerns on 2nd embodiment, Comprising: (a) is a perspective view, (b) is a schematic cross section.

[First embodiment]
The lid joining method according to the first embodiment of the present invention will be described in detail with reference to the drawings as appropriate. First, as shown in FIG. 1, each member which comprises the structure 1 formed by this embodiment is demonstrated. The vertical and horizontal directions in the description follow the arrows in FIG.

  As shown in FIG. 1, the structure 1 includes a cylindrical body 2 and a cover plate 3 that covers a part of the opening of the cylindrical body 2. The cylindrical body 2 is a cylindrical member that has a substantially rectangular ring shape in plan view and opens in the vertical direction. The cylindrical body 2 includes an end surface 4, an outer peripheral surface 5, and an inner peripheral surface 6. The front side of the upper part of the cylindrical body 2 is cut out from the end face 4 at a predetermined height. Thereby, the end surface 4 has the 1st end surface 4a and the 2nd end surface 4b formed in the position lower than the 1st end surface 4a. A surface perpendicular to the first end surface 4a and the second end surface 4b is defined as an upright surface 4c. The cylindrical body 2 is formed from a member capable of friction stirring such as aluminum or an aluminum alloy. The plate thickness of the cylindrical body 2 is not particularly limited, but is set to 2 mm in the present embodiment. Of the cylindrical body 2, a portion related to the first end surface 4a side (rear side) is referred to as a cylindrical rear portion 2a, and a portion related to the second end surface 4b side (front side) is referred to as a cylindrical front portion 2b. The cylindrical body 2 is rectangular in plan view in the present embodiment, but may have another shape.

  As shown in FIGS. 1 and 2, the cover plate 3 is a member that covers the opening of the cylindrical front portion 2 b, and is placed on the second end surface 4 b of the cylindrical body 2. The cover plate 3 is a plate-like member having a front surface 3a, a back surface 3b, and a side surface 3c. When the cover plate 3 is placed on the second end surface 4 b, the back surface 3 b of the cover plate 3 comes into contact with the second end surface 4 b of the cylindrical body 2. Further, the side surface 3 c of the cover plate 3 comes into contact with the vertical surface 4 c of the cylindrical body 2. As shown in FIG. 2B, when the cover plate 3 is placed on the second end surface 4b, the second end surface 4b and the back surface 3b of the cover plate 3 come into contact with each other, and an interface J1 is formed.

  The length of the cover plate 3 in the front-rear direction and the left-right direction is formed to be greater than the length of the cylindrical front portion 2b in the front-rear direction and the left-right direction. That is, as shown in FIGS. 2A and 2B, when the cover plate 3 is placed on the second end surface 4 b, the cover plate 3 projects outward from the outer peripheral surface 5 of the cylindrical body 2. In the present embodiment, a portion of the lid plate 3 that protrudes outward from the outer peripheral surface 5 of the cylindrical body 2 is defined as an extending portion 3d. The length of the extended portion 3d (the length from the outer peripheral surface 5 of the cylindrical body 2 to the side surface 3c of the lid plate 3) may be set as appropriate according to the joining step described later. The outer diameter of the shoulder part G1 of the rotating tool G is set to be larger.

  Next, a rotary tool used by friction stir welding described later will be described with reference to FIG. The rotating tool G shown in FIG. 3 is made of a metal material harder than the cylindrical body 2 such as tool steel, and has a columnar shoulder portion G1 and a stirring pin protruding from the lower end surface G11 of the shoulder portion G1 ( Probe) G2.

  The lower end face G11 of the shoulder part G1 is a part that plays a role of pressing the plastic fluidized metal to prevent scattering to the surroundings, and in this embodiment, it is formed in a concave shape. The stirring pin G2 hangs down from the center of the lower end surface G11 of the shoulder portion G1, and is tapered in this embodiment. A stirring blade engraved in a spiral shape is formed on the peripheral surface of the stirring pin G2. In this embodiment, the length L of the stirring pin G2 is set to be equal to or slightly longer than the thickness of the cover plate 3. In the present embodiment, the rotary tool G is formed as described above. However, the size and shape of the rotary tool G may be set according to the material and thickness of the cylindrical body 2 and the cover plate 3.

  Next, the lid joining method of the present invention will be described. In the lid joining method according to the present embodiment, (1) a preparation step, (2) a joining step, and (3) a cutting step are performed.

(1) Preparatory process In a preparatory process, the degreasing process which performs the degreasing process with respect to the cylindrical body 2 and the cover board 3, and the mounting process which mounts the cover board 3 on the cylindrical body 2 are performed.

  In the degreasing step, dirt attached to the cylindrical body 2 and the cover plate 3 is removed. In the degreasing step, the cylindrical body 2 and the cover plate 3 are dipped in a degreasing solution to remove oil, cutting chips and the like attached to the cylindrical body 2 and the cover plate 3.

  In the placing step, as shown in FIGS. 1 and 2, the cover plate 3 is placed on the cylindrical front portion 2b. That is, the back surface 3b and the side surface 3c of the cover plate 3 are brought into contact with the second end surface 4b and the vertical surface 4c of the cylindrical body 2, respectively. An interface J1 is formed by the second end surface 4b and the back surface 3b of the cover plate 3.

(2) Joining process In the joining process, the rotating tool G rotated at a high speed is moved along the interface J1 to perform friction stir welding. As shown in FIG. 4A, an insertion position (start position) SM <b> 1 for inserting the rotary tool G is set at one end of the surface 3 a of the lid plate 3. In the present embodiment, the insertion position SM1 is set outside the cylindrical body 2 in the cover plate 3, that is, in the extended portion 3d. A starting point s1 is set at the center in the width direction of the second end surface 4b of the cylindrical body 2. In the joining step, the rotating tool G is moved toward the starting point s1 while the stirring pin G2 (see FIG. 3) of the rotating tool G is inserted into the insertion position SM1. When inserting the rotary tool G, as shown in FIG. 5A, the rotary tool G is moved from the insertion position SM1 to the start point s1 to the interface J1 while gradually increasing the insertion amount of the rotary tool G.

  The insertion amount of the rotary tool G may be set as appropriate, but in this embodiment, it is set to such an extent that the tip of the stirring pin G2 reaches the second end surface 4b of the cylindrical body 2. The insertion amount of the rotary tool G is set so that the lower end surface G11 of the shoulder portion G1 of the rotary tool G is positioned below the surface 3a of the lid plate 3.

  When the rotating tool G reaches the interface J1, the rotating tool G is moved along the interface J1, as shown in FIG. As shown in FIG. 5B, the rotary tool G is moved so that the center in the width direction of the second end face 4b and the axis of the rotary tool G overlap. The cylindrical body 2 and the cover plate 3 around the interface J1 are integrally plastically fluidized to form a plasticized region W1. The “plasticization region” includes both a state where the rotating tool G is heated by frictional heat and is actually plasticized, and a state where the rotating tool G passes and returns to room temperature.

  As shown in FIG. 4C, when the rotary tool G reaches the end point e1 set at the center in the width direction of the second end surface 4b of the cylindrical body 2, it is set at the other end of the surface 3a of the cover plate 3. Move to extraction position (end position) EM1. The extraction position EM1 is set on the outer side of the cylindrical body 2 in the cover plate 3, that is, on the extended portion 3d.

  In the joining step, as shown in FIG. 5C, the rotational tool G is moved while gradually reducing the insertion amount from the end point e1 to the extraction position EM1. When the tip of the stirring pin G2 of the rotating tool G reaches the extraction position EM1, the rotating tool G is detached from the surface 3a of the cover plate 3.

  Since the interface J1 is frictionally stirred by the joining step, the cylindrical body 2 and the cover plate 3 can be integrally formed. In addition, in the joining process of this embodiment, it set so that the cylindrical body 2 might be located in the advancing direction left side, rotating the rotation tool G counterclockwise. In the joining process of the present embodiment, in the plasticizing region W1, the shear side (the relative speed of the outer periphery of the rotary tool G with respect to the bonded portion is the magnitude of the moving speed to the magnitude of the tangential speed on the outer periphery of the rotary tool G Is set so as to be at a position away from the opening of the cylindrical body 2. That is, according to the present embodiment, since the shear side is set to be located outside the cylindrical body 2, even if a cavity defect occurs due to frictional stirring, the shear side is positioned far from the opening of the cylindrical body 2. be able to. By the way, when rotating the rotary tool G to the right, if the cylindrical body 2 is set so as to be positioned on the right side in the traveling direction, even if a bonding defect occurs, it is positioned on the side far from the opening of the cylindrical body 2. Can do.

(3) Cutting process In a cutting process, a part of lid 3 is cut off by cutting. In the cutting process according to the present embodiment, an extending part cutting process for excising the extending part 3d of the lid plate 3 and a surface cutting process for excising the surface 3a of the lid plate 3 are performed.

  In the extending portion cutting step, as shown in FIGS. 6A and 6B, the extending portion 3d (two-dot chain line portion) of the cover plate 3 is cut off. That is, the part which protrudes from the outer peripheral surface 5 of the cylindrical body 2 among the cover plates 3 is excised. The cutting method may be performed by a known cutting process. Thereby, the outer peripheral surface 5 of the cylindrical body 2 and the side surface 3e after the cutting of the cover plate 3 are flush with each other.

  In the surface cutting step, as shown in FIG. 6B, the surface 3a of the cover plate 3 is cut to a predetermined thickness. In the above-described joining step, the shoulder portion G1 of the rotary tool G is pushed into the cover plate 3, so that a groove M having a depth H1 is formed on the surface 3a of the cover plate 3. In the surface cutting process, cutting is performed from the surface 3a of the cover plate 3 with a predetermined thickness in order to cut off the burrs and the like generated by the grooves M and the joining process. The thickness H2 of the cutting process may be set as appropriate according to the depth H1 and the like of the groove M, but it is preferable to set at least the thickness H2 to be greater than the depth H1.

  According to the lid joining method according to the present embodiment described above, the extending portion 3d in which the extraction position EM1 for separating the stirring pin G2 of the rotary tool G is set is provided on the lid plate 3, and after the friction stir welding, the extending portion is provided. Since the portion 3d is excised, no loophole of the rotary tool G remains in the structure 1.

  In addition, after the friction stir welding, since the insertion amount is gradually reduced while moving the rotary tool G from the interface J1 to the extraction position EM1, the rotary tool G does not break through the cover plate 3. Further, in the joining process, by performing frictional stirring while gradually increasing the insertion amount of the rotary tool G from the insertion position SM1 to the starting point s1, the rotary tool G may break through the cover plate 3 before reaching the interface J1. Absent. Thereby, it can avoid that the joined structure 1 is wrinkled.

  Further, by providing the extending portion 3d on the cover plate 3, it is not necessary to prepare a tab material or the like for inserting or removing the rotary tool G, so that the labor and time can be reduced. Moreover, since the surface 3a of the cover plate 3 is excised in the surface cutting step, the surface of the cover plate 3 can be smoothed.

  Further, in the joining step, the friction stirring is performed in a state where the stirring pin G2 is in contact with the second end surface 4b of the cylindrical body 2, so that the interface J1 can be reliably joined.

  The positions of the insertion position SM1 and the extraction position EM1 in the joining process may be set as appropriate according to the shape of the structure 1. Moreover, in this embodiment, although the cover plate 3 was mounted so that the opening of the cylindrical front part 2b of the cylindrical body 2 might be covered, you may mount the cover plate 3 so that the cylindrical rear part 2a may be covered. .

[Second Embodiment]
Next, a second embodiment of the present invention will be described. As shown in FIGS. 7 and 8, in the present embodiment, the cylindrical body 52 is a cylindrical point, the lid plate 53 is a circular plate, and the entire opening of the cylindrical body 52 is covered with the lid plate 53. This is different from the first embodiment in that it is covered with. About 2nd embodiment, detailed description is abbreviate | omitted about the part which is common in 1st embodiment.

  The structure 51 according to the second embodiment includes a cylindrical body 52 and a cover plate 53 that closes one opening of the cylindrical body 52. The cylindrical body 52 has a cylindrical shape and opens up and down. The cylindrical body 52 and the cover plate 53 are made of a metal capable of frictional stirring. The outer diameter of the lid plate 53 is formed larger than the outer diameter of the cylindrical body 52. Therefore, as shown in FIG. 7B, when the cover plate 53 is placed on the end surface 54 of the cylindrical body 52, the outer peripheral edge of the cover plate 53 is stretched outside the outer peripheral surface 55 of the cylindrical body 52. put out. A portion of the cover plate 53 that protrudes outward from the outer peripheral surface 55 of the cylindrical body 52 is defined as an extending portion 53d. The end surface 54 of the cylindrical body 52 and the back surface 53b of the cover plate 53 are in contact with each other, so that an interface J2 is formed.

Next, the lid joining method of the present invention will be described. In the lid joining method according to this embodiment, (1
) Prepare step, (2) Joining step, (3) Cutting step. Since the preparation process is substantially the same as that of the first embodiment, description thereof is omitted.

(2) Joining Step In the joining step, as shown in FIGS. 8A and 8B, the rotary tool G rotated at a high speed is moved along the interface J2 to perform friction stir welding. In the joining process according to the present embodiment, the rotary tool G is inserted into the insertion position SM2 set in the extending portion 53d of the cover plate 53, and as shown in FIG. 8B, the rotary tool G is moved toward the interface J2. The rotary tool G is moved while being pushed in so that the amount of insertion becomes gradually larger.

  When the tip of the stirring pin G2 of the rotating tool G is moved until it reaches the end face 54 of the cylindrical body 52, the rotating tool G is moved once along the interface J2. By the frictional stirring of the rotary tool G, a plasticized region W2 is formed in the lid plate 53.

  When the rotating tool G is made to make one turn, the rotating tool G is moved to the extraction position EM2 set in the extending portion 53d of the cover plate 53 so as to overlap with a part of the existing plasticized region W2. As shown in FIG. 8B, when the rotary tool G is moved from the interface J2 to the extraction position EM2, friction stirring is performed while gradually reducing the insertion amount of the rotary tool G. When the tip of the stirring pin G2 of the rotating tool G reaches the extraction position EM2, the rotating tool G is detached from the lid plate 53.

  In the joining process of the present embodiment, the rotary tool G is moved clockwise with respect to the cylindrical body 52 while being rotated clockwise. Thereby, even if a bonding defect is formed, it can be positioned on the left side in the advancing direction of the plasticizing region W2, that is, on the side farther from the opening of the cylindrical body 52.

(3) Cutting process In a cutting process, a part of lid 53 is cut off by cutting. In the cutting process according to the present embodiment, an extended part cutting process for cutting off the extended part 53 d of the cover plate 53 and a surface cutting process for cutting off the surface 53 a of the cover plate 53 are performed.

  In the extending portion cutting step, the extending portion 53d of the cover plate 53 shown in FIG. That is, a portion of the lid plate 53 that protrudes laterally from the outer peripheral surface 55 of the cylindrical body 52 is excised. The cutting method may be performed by a known cutting process. Thereby, the outer peripheral surface 55 of the cylindrical body 52 and the side surface after the cutting of the cover plate 3 are flush with each other.

  In the surface cutting step, the surface 53a of the cover plate 53 shown in FIG. 8B is cut to a predetermined thickness. In the above-described joining step, the shoulder portion G1 of the rotary tool G is pushed into the lid plate 53, so that a groove is formed on the surface 53a of the lid plate 53. In the surface cutting process, cutting is performed with a predetermined thickness from the surface 53a of the lid plate 53 in order to cut out burrs and the like generated by the grooves and the joining process. What is necessary is just to set the thickness of cutting process suitably according to the depth etc. of a groove | channel.

  According to the lid joining method according to the second embodiment, the following effects can be exhibited in addition to the effects according to the first embodiment. According to the lid joining method according to the present embodiment, even when the interface J2 has an annular shape, the insertion position SM2 and the extraction position EM2 of the joining process are set in the extended portion 53d of the lid plate 53, and the joining process By removing the extended portion 53d later, it is possible to prevent the punched hole of the rotary tool G from remaining in the structure 51.

  Further, in the joining step, the interface J2 is reliably joined by setting the movement trajectory of the rotating tool G so that the plasticizing region W2 overlaps while making the rotating tool G go around along the cylindrical body 52. Can do.

  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 shape, size, etc. of the rotary tool G may be appropriately set according to the material and thickness of the cylindrical body and the cover plate.

DESCRIPTION OF SYMBOLS 1 Structure 2 Cylindrical body 3 Cover plate 3a Front surface 3b Back surface 3c Side surface 3d Extension part 4 End surface 4a First end surface 4b Second end surface 5 Outer peripheral surface 6 Inner peripheral surface J1 Interface G Rotating tool G1 Shoulder part G2 Stirring pin SM1 Position EM1 Extraction position

Claims (5)

A lid plate covering at least a part of the opening of the cylindrical body is placed on the end surface of the cylindrical body, a rotary tool is pushed in from the surface of the lid plate, and the tip of the stirring pin of the rotary tool is placed on the end surface And a lid joining method for fixing the cylindrical body and the lid plate by friction stir welding while being positioned in the vicinity of the interface between the lid plate and the back surface of the lid plate,
The cover plate is provided with an extending portion extending outward from the outer peripheral surface of the cylindrical body, and an extraction position for separating the stirring pin is set at the extending portion,
After the stirring pin is inserted from the surface of the lid plate and the cylindrical body and the lid plate are fixed by friction stir welding, the rotational tool is moved from the interface to the extraction position while gradually reducing the insertion amount. A joining step for separating the stirring pin from the lid plate at the extraction position;
And a cutting step of cutting off the extended portion. Set the insertion position to insert the stirring pin into the extended portion,
2. The joining step according to claim 1, wherein when the rotary tool is inserted, the rotary tool is moved from the insertion position toward the interface while gradually increasing the insertion amount of the rotary tool. Lid joining method.   The lid joining method according to claim 1 or 2, wherein after fixing the cylindrical body and the lid plate, a surface of the lid plate is cut out with a predetermined thickness.   The lid joining method according to any one of claims 1 to 3, wherein the friction stir welding is performed in a state in which a tip of the stirring pin is in contact with an end face of the cylindrical body. The end surface of the cylindrical body includes a second end surface having a step with respect to the first end surface and the first end surface,
5. The lid joint according to claim 1, wherein the lid plate is placed so as to cover one of the openings on the first end face side and the second end face side. Method.

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