JP5915796B2 - Friction stir welding method - Google Patents

Description

  The present invention relates to a friction stir welding method.

  Patent Document 1 discloses a technique in which friction stir welding is performed from the front side and the back side of the abutting portion between metal members, and the plasticizing regions formed by the friction stir welding are brought into contact with each other so that the abutting portion is joined without a gap. Is disclosed. According to this technique, the airtightness and watertightness of the joined metal members can be improved.

JP 2008-87036 A

  When joining metal members having large plate thicknesses by conventional joining methods, it is necessary to increase the length and outer diameter of the stirring pin. Further, as the stirring pin becomes larger, the shoulder portion It is necessary to increase the outer diameter of the. However, when the outer diameter of the shoulder portion is increased, the friction between the metal member and the shoulder portion increases, and there is a problem that the load applied to the friction stirrer increases. This makes it difficult to join a deep position of a metal member having a particularly large plate thickness.

  From such a viewpoint, an object of the present invention is to provide a friction stir welding method capable of joining to a deep position of a butt portion by reducing a load applied to the friction stirrer.

In order to solve such problems, the present invention provides a friction stir welding method for joining two metal members using a rotary tool provided with a stirring pin and connected to a rotating shaft of a friction stirrer. Insert the rotated stirring pin into the abutting part between the members, and friction between the friction stirrer and the rotating tool with only the stirring pin of the rotating tool in contact with the metal member to generate frictional heat. A main joining step for performing stir welding; a concave groove forming step for forming a concave groove by cutting the surface of the plasticized region surrounded by the step formed in the main joining step after the main joining step; A step of arranging an auxiliary member in the groove after the groove forming step, and an auxiliary member joining step of joining the metal member and the auxiliary member after the arranging step , A spiral groove on the outer surface The rotating tool for temporary joining used in the auxiliary member joining step is configured with a shoulder part and a stirring pin, and the shoulder part has a columnar shape and is connected to a rotating shaft of the friction stirrer. The temporary tool rotating tool while pressing the lower end surface of the shoulder portion into the surface of the metal member and the auxiliary member in the auxiliary member joining step. It is characterized by moving.

  According to such a method, the friction between the metal member and the rotating tool can be reduced compared to the conventional friction stir welding method in which the shoulder is pressed against the metal member by making only the stirring pin the portion to be brought into contact with the metal member. The load applied to the friction stirrer can be reduced. That is, according to the present invention, since the stirring pin can be inserted to a deep position of the metal member, even a metal member having a large plate thickness can be joined to a deep position. Moreover, the metal shortage in this joining process can be replenished by including an auxiliary member joining process.

Further, the present invention is a friction stir welding method for joining two metal members using a rotary tool provided with a stirring pin and connected to a rotating shaft of a friction stirrer, wherein the metal member rotates at a butt portion between the metal members. Main joining step in which friction stir welding is performed in a state where only the stirring pin of the rotary tool out of the friction stirrer and the rotary tool is brought into contact with the metal member to generate frictional heat. And after the main joining step, after forming the concave groove by cutting the surface of the plasticized region surrounded by the step formed in the main joining step, after the concave groove forming step, A placement step of placing an auxiliary member in the concave groove, and an auxiliary member joining step of joining the metal member and the auxiliary member after the placement step, wherein a spiral groove is formed on the outer peripheral surface of the stirring pin. The main connection In the process, a first main joining step of performing friction stir welding from the front side of the metal member and a second main joining step of performing friction stir welding from the back side of the metal member are performed, and the first A rotating tool for temporary joining used in the auxiliary member joining step is made by bringing a plasticizing region formed in the main joining step and a plasticizing region formed in the second main joining step into contact with each other. The shoulder portion has a columnar shape and is a portion that is connected to the rotating shaft of the friction stirrer and a portion that holds the plastic fluidized metal, and in the auxiliary member joining step, The temporary joining rotary tool is moved while pushing the lower end surface of the shoulder portion into the surfaces of the metal member and the auxiliary member.

  According to such a method, the friction between the metal member and the rotating tool can be reduced compared to the conventional friction stir welding method in which the shoulder is pressed against the metal member by making only the stirring pin the portion to be brought into contact with the metal member. The load applied to the friction stirrer can be reduced. That is, according to the present invention, since the stirring pin can be inserted to a deep position of the metal member, even a metal member having a large plate thickness can be joined to a deep position. Moreover, since friction stir welding can be performed with respect to the entire length of the abutting portion in the thickness direction, airtightness and watertightness can be improved. Moreover, the metal shortage in this joining process can be replenished by including an auxiliary member joining process.

  Moreover, it is preferable to include the temporary joining process which performs temporary joining of the said metal members before performing the said main joining process. According to such a method, the metal members can be prevented from being separated from each other.

Moreover, it is preferable to perform the said main joining process by inserting the stirring pin of the said rotation tool in the said prepared hole, after arrange | positioning the tab material on the side of the said abutting part and providing the prepared hole in the said tab material. According to this method, it is possible to reduce the press-fit resistance when the rotary tool is pushed into the metal member. In addition, before the main joining step, it is preferable that the two metal members are placed on a frame of a friction stirrer and the two metal members are restrained so as not to move using a jig.

  According to the friction stir welding method according to the present invention, it is possible to join a deep portion of the abutting portion by reducing the load applied to the friction stirrer.

(A) is the side view which showed the rotation tool for this joining of this embodiment, (b) is the schematic cross section which showed the joining form of the rotation tool for this joining. (A) is the side view which showed the rotary tool for temporary joining of this embodiment, (b) is the schematic cross section which showed the joining form of the rotary tool for temporary joining. It is the figure which showed the preparation process of this embodiment, Comprising: (a) is a perspective view, (b) is a top view. It is the top view which showed the 1st preliminary | backup process of this embodiment, Comprising: (a) is in the middle of joining, (b) shows the time of completion | finish. It is the top view which showed the 1st main joining process of this embodiment, Comprising: (a) is in the middle of joining, (b) shows the time of completion | finish. It is the perspective view which showed the 1st repair process of this embodiment. It is the figure which showed the repair member joining process in the 1st repair process of this embodiment, Comprising: (a) is a top view, (b) is sectional drawing. It is sectional drawing which showed the 1st repair process after this embodiment. (A) is sectional drawing which showed the 2nd this joining process of this embodiment, (b) is sectional drawing which showed the 2nd repair process of this embodiment. It is the figure which showed the modification of the repair process, Comprising: (a) shows a cutting process, (b) shows a build-up welding process. It is sectional drawing of the conditions of Example 1, and each plasticization area | region. 1 is a cross-sectional view for explaining Example 1. FIG. It is sectional drawing of the conditions of Example 2, and each plasticization area | region. It is sectional drawing for demonstrating Example 2, 3. FIG. It is sectional drawing of the conditions of Example 3, and each plasticization area | region.

  Embodiments of the present invention will be described in detail with reference to the drawings. First, the main joining rotary tool and the temporary joining rotary tool used in the present embodiment will be described.

  As shown in FIG. 1A, the main joining rotary tool F is composed of a connecting portion F1 and a stirring pin F2. The main rotating tool F for joining is formed of, for example, tool steel. The connection part F1 is a part connected to the rotating shaft D of the friction stirrer shown in FIG. The connecting portion F1 has a cylindrical shape, and is formed with screw holes B and B to which bolts are fastened.

  The stirring pin F2 hangs down from the connecting portion F1 and is coaxial with the connecting portion F1. The stirring pin F2 is tapered as it is separated from the connecting portion F1. A spiral groove F3 is formed on the outer peripheral surface of the stirring pin F2.

  As shown in FIG. 1B, when the friction stir welding is performed using the main rotating tool F, only the rotated stirring pin F2 is inserted into the metal member 1, and the metal member 1 and the connecting portion F1 are inserted. And move it apart. In other words, the friction stir welding is performed with the base end portion of the stirring pin F2 exposed. A plasticized region W is formed in the movement locus of the main rotating tool F for bonding by hardening the friction-stirred metal.

  As shown in FIG. 2A, the temporary bonding rotary tool G includes a shoulder portion G1 and a stirring pin G2. The temporary joining rotary tool G is made of, for example, tool steel. As shown in FIG. 2B, the shoulder portion G1 is a portion that is connected to the rotating shaft D of the friction stirrer and is a portion that holds the plastic fluidized metal. The shoulder portion G1 has a cylindrical shape. The lower end surface of the shoulder portion G1 has a concave shape in order to prevent the fluidized metal from flowing out.

  The stirring pin G2 is suspended from the shoulder portion G1, and is coaxial with the shoulder portion G1. The stirring pin G2 is tapered as it is separated from the shoulder portion G1. A spiral groove G3 is formed on the outer peripheral surface of the stirring pin G2.

  As shown in FIG. 2B, when friction stir welding is performed using the temporary welding rotating tool G, the rotated stirring pin G2 and the lower end of the shoulder portion G1 are inserted into the metal member 1 and moved. . A plasticized region w is formed in the movement locus of the temporary bonding rotary tool G by hardening the friction-stirred metal.

  Next, a specific friction stir welding method of this embodiment will be described. In this embodiment, (1) preparation step, (2) first preliminary step, (3) first main joining step, (4) first repair step, (5) second preliminary step, (7 2) a second main joining step and (8) a second repairing step. The first preliminary process, the first main joining process, and the first repair process are executed from the surface side of the metal member 1, and the second preliminary process, the second main joining process, and the first repair process are performed. The second repair process is a process executed from the back side of the metal member 1.

(1) Preparation process
The preparation process will be described with reference to FIG. In the preparatory process according to the present embodiment, the first tab member 2 and the second tab member 3 are disposed on both sides of the butting portion J1 of the metal members 1 and 1, the butting step of butting the metal members 1 and 1 to be joined. A tab material arranging step and a welding step of temporarily joining the first tab material 2 and the second tab material 3 to the metal members 1 and 1 by welding.

  In the abutting step, the metal members 1 and 1 to be joined are arranged in an L shape, and the side surface of the other metal member 1 is brought into close contact with the side surface of the one metal member 1. Although the metal member 1 should just be a metal which can be friction-stirred, in this embodiment, an aluminum alloy is used.

In the tab material arranging step, the first tab material 2 is arranged on one end side (outside) of the abutting portion J1 of the metal members 1 and 1, and the contact surface 21 of the first tab material 2 (see FIG. 3B). Is brought into contact with the outer side surfaces of the metal members 1 and 1, and the second tab member 3 is disposed on the other end side of the abutting portion J1 so that the contact surfaces 31 and 31 of the second tab member 3 (in FIG. b) is brought into contact with the inner side surfaces of the metal members 1, 1. When the metal members 1 and 1 are combined in an L shape, one of the first tab material 2 and the second tab material 3 (the second tab material 3 in the present embodiment) is used by the metal members 1 and 1. It arrange | positions in the formed corner part (corner part formed by the inner side surface of the metal members 1 and 1).

  In the welding process, the corners 2a, 2a formed by the metal member 1 and the first tab material 2 are welded to join the metal member 1 and the first tab material 2, and the metal member 1 and the second tab material. The metal corners 1 a and the second tab member 3 are joined by welding the corners 3 a and 3 a formed by 3.

  When the preparation process is completed, the metal members 1, 1, the first tab material 2 and the second tab material 3 are placed on a frame of a friction stirrer (not shown) and cannot be moved using a jig (not shown) such as a clamp. To be restrained.

(2) First preliminary process
The first preliminary process includes a first tab material joining step for joining the abutting portion J2 between the metal members 1, 1 and the first tab material 2, and a temporary joining step for temporarily joining the abutting portion J1 of the metal members 1, 1. And a second tab material joining step for joining the butted portion J3 of the metal members 1, 1 and the second tab material 3, and a pilot hole formation for forming a pilot hole at the friction stirring start position in the first main joining step Process.

  As shown in FIGS. 4 (a) and 4 (b), one temporary joining rotary tool G is moved so as to form a one-stroke movement trajectory (bead), and the butt portions J1, J2, J3 are moved. Then, friction stir is performed continuously.

  First, the stirring pin G2 of the rotary tool G for temporary joining is rotated counterclockwise and inserted into a start position SP provided at an appropriate position of the first tab member 2 to start frictional stirring. The relative movement is made toward the starting point s2 of the material joining step.

  When the frictional stirring is continuously performed up to the starting point s2 of the first tab material joining step by relatively moving the temporary joining rotary tool G, the first tab material joining is performed without removing the temporary joining rotary tool G at the starting point s2. Move to the process.

  In the first tab material joining step, friction agitation is performed on the abutting portion J2 between the first tab material 2 and the metal members 1 and 1. Specifically, a friction stir route is set on the joint between the metal members 1, 1 and the first tab member 2, and the temporary joining rotary tool G is relatively moved along the route, whereby the abutting portion J 2. Friction agitation is performed. In the present embodiment, the friction stir is continuously performed from the start point s2 to the end point e2 of the first tab member joining step without causing the temporary joining rotary tool G to be detached.

  In addition, when the rotating tool G for temporary joining is rotated to the left, there is a possibility that a fine joining defect may occur on the right side in the traveling direction. It is desirable to set the positions of the start point s2 and the end point e2 of the first tab material joining step so that 1 is located. If it does in this way, since it becomes difficult to generate | occur | produce a joining defect on the metal member 1 side, it becomes possible to obtain a high quality joined body.

  When the rotary tool G for temporary joining reaches the end point e2 of the first tab material joining step, the friction stir is continuously performed to the start point s1 of the temporary joining step without ending the friction stirring at the end point e2, and the temporary joining step is performed as it is. Transition. In the present embodiment, the friction stir route from the end point e2 of the first tab material joining process to the start point s1 of the temporary joining process is set to the first tab material 2.

  In the temporary joining step, friction agitation is performed on the abutting portion J1 of the metal members 1 and 1. Specifically, a friction stir route is set on the joint between the metal members 1 and 1, and the temporary joining rotary tool G is relatively moved along the route, whereby the stir portion J1 is friction stir. . In the present embodiment, the friction stir is continuously performed from the start point s1 to the end point e1 of the temporary joining step without causing the temporary joining rotary tool G to be detached on the way.

  When the temporary joining rotary tool G reaches the end point e1 of the temporary joining process, the process proceeds to the second tab material joining process as it is. That is, the process proceeds to the second tab material joining step without detaching the temporary joining rotary tool G at the end point e1 of the temporary joining step which is also the starting point s3 of the second tab material joining step.

  In the second tab material joining step, friction stirring is performed on the abutting portions J3 and J3 between the metal members 1 and 1 and the second tab material 3. In the present embodiment, since the start point s3 of the second tab material joining step is located in the middle of the abutting portions J3 and J3, it is turned back to the friction stir route from the start point s3 to the end point e3 of the second tab material joining step. After providing the point m3 and moving the temporary welding rotary tool G from the start point s3 to the turning point m3 (see FIG. 4A), the temporary joining rotary tool G is moved from the turning point m3 to the end point e3. (See FIG. 4B), the friction stir is continuously performed from the start point s3 to the end point e3 of the second tab material joining step. That is, after revolving the temporary joining rotary tool G between the start point s3 and the turning point m3, the temporary joining rotary tool G is moved from the end point e3 to the end point e3 from the start point s3 to the end point e3. Friction stirring is performed continuously. The route of friction stirring from the start point s3 to the turning point m3 and the route of friction stirring from the turning point m3 to the end point e3 are set on the joint between the metal member 1 and the second tab member 3, respectively.

  The positional relationship among the start point s3, the turning point m3, and the end point e3 is not particularly limited. However, when the temporary joining rotary tool G is rotated counterclockwise as in this embodiment, at least friction from the turning point m3 to the end point e3. The positions of the start point s3, the turning point m3, and the end point e3 of the second tab material joining step may be set so that the metal members 1 and 1 are located on the left side in the traveling direction of the temporary joining rotary tool G in the stirring route. desirable. In this case, between the starting point s3 and the turning point m3, a route for friction stirring is set on the joint between the metal member 1 and the second tab member 3 both in the forward path and in the return path, and the temporary joining book is set along the route. It is desirable to move the rotating tool for joining. In this way, even if the metal member 1 is positioned on the right side in the traveling direction of the temporary bonding rotary tool G between the start point s3 and the turning point m3, and a bonding defect occurs on the metal member 1 side, In the subsequent frictional stirring from the turning point m3 to the end point e3, the metal member 1 is located on the left side in the direction of travel of the temporary joining rotary tool G, so that the above-described joining defects are corrected and high-quality joining is achieved. The body can be obtained.

  By the way, when the temporary joining rotary tool G is rotated to the right, the metal members 1 and 1 are positioned on the right side in the traveling direction of the temporary joining rotary tool G in the friction stir route from the turning point to the end point. It is desirable to set the position of the start point, the turning point, and the end point of the second tab material joining step. Specifically, although illustration is omitted, a turn is provided at the position of the end point e3 when the temporary joining rotary tool G is rotated counterclockwise, and the turning point m3 when the temporary joining rotary tool G is rotated counterclockwise is provided. An end point may be provided at the position.

  As shown in FIG. 4B, when the temporary joining rotary tool G reaches the end point e3 of the second tab material joining step, the friction stir is not finished at the end point e3, and the second tab material 3 is provided. Friction stirring is continuously performed up to the end position EP. When the temporary joining rotary tool G reaches the end position EP, the temporary joining rotary tool G is raised while rotating, and the stirring pin G2 is separated from the end position EP.

  Then, a pilot hole formation process is performed. The pilot hole forming step is a step of forming a pilot hole at the friction stirring start position in the first main joining step. Although a pilot hole may be newly formed, in this embodiment, the diameter of the punched hole formed when the stirring pin G2 of the rotary tool G for temporary bonding is removed is increased by a drill or the like to form the pilot hole. Form. In this way, it is possible to omit or simplify the work for preparing the pilot hole, so that the work time can be shortened. In addition, you may utilize the above-mentioned punch hole as a pilot hole as it is.

(3) 1st main joining process When the 1st preliminary process is completed, the 1st main joining process which joins the butt | matching part J1 of the metal members 1 and 1 in earnest is performed. In the first main joining step according to the present embodiment, the main joining rotating tool F shown in FIG. 1A is used, and the front side of the metal member 1 with respect to the abutting portion J1 in a temporarily joined state. Friction stirring is performed.

  In the first main joining step, first, as shown in FIG. 5, the stirring pin F2 is moved to the start position SM1 while rotating the main welding rotating tool F to the right (that is, the end position EP shown in FIG. 4B). And start friction stir.

  After the friction stir to one end of the abutting portion J1 of the metal members 1 and 1, the rotary tool F for main joining is directly plunged into the abutting portion J1, and the friction stir route set on the joint of the metal members 1 and 1 is entered. A frictional stirring is continuously performed from one end to the other end of the abutting portion J1 by relatively moving the main rotating tool F for welding. Here, as shown in FIG. 1B, the connecting portion F1 of the main rotating tool F and the metal member 1 are separated from each other, and only the stirring pin F2 is inserted into the abutting portion J1. As shown in FIG. 5 (b), when the main rotating tool F is moved relative to the other end of the abutting portion J1, the abutting portion J2 is moved across the abutting portion EM1 while performing frictional stirring. Move.

  When the main welding rotary tool F reaches the end position EM1, the main welding rotary tool F is raised while rotating to disengage the stirring pin F2 from the end position EM1. Note that if the stirring pin F2 is separated upward at the end position EM1, a punch hole having substantially the same shape as the stirring pin F2 is inevitably formed, but in this embodiment, it is left as it is.

(4) First repair process
When the first main joining step is completed, the first repairing step is performed on the plasticized region W1 formed on the metal member 1 by the first main joining step. In the first repair process according to the present embodiment, as shown in FIGS. 6 and 7, a groove forming process for forming the groove M, a disposing process for arranging the auxiliary member 4 in the groove M, and a metal member. An auxiliary member joining step for joining 1 and the auxiliary member 4 is performed.

  In the concave groove forming step, as shown in FIG. 6, the concave groove M is formed on the surface of the plasticized region W <b> 1 formed along with the movement of the main welding rotary tool F. In the concave groove forming step, for example, the surface of the burr or plasticized region W1 is cut using an end mill or the like to form a concave groove M having a rectangular cross-sectional view.

  In the arranging step, the auxiliary member 4 is arranged in the concave groove M. The auxiliary member 4 is a metal plate made of the same material as the metal member 1. The auxiliary member 4 has the same shape as the concave groove M. The thickness of the auxiliary member 4 is substantially equal to the depth of the concave groove M.

  In the auxiliary member joining step, as shown in FIG. 7A, friction stir is applied to the abutting portion J4, which is the abutting portion of the auxiliary member 4, the metal member 1, the first tab material 2, and the second tab material 3. Join. Specifically, the rotated rotary tool G for temporary joining is inserted into the start position SH1 set on the second tab member 3, and moved around the abutting portion J4 to the end position EH1. As shown in FIG. 7B, in the auxiliary member joining step, the temporary joining rotary tool G is moved while pushing the shoulder portion G <b> 1 into the surface 12 of the metal member 1. Further, the stirring pin G2 of the temporary bonding rotary tool G is set longer than the thickness of the auxiliary member 4.

  As shown in FIG. 8, when the two-stage plasticized region w <b> 2 is formed with respect to the auxiliary member 4 by rotating the temporary joining rotary tool G, the auxiliary member 4 is entirely covered with the plasticized regions w <b> 2 and w <b> 2. . Moreover, since the plasticization area | region W1 and the plasticization area | region w2 overlap, airtightness and watertightness can be improved more.

  When the step between the surface 12 of the metal member 1 and the surface of the plasticized region W1 is large after the first main joining step, the groove forming step may be omitted. In the auxiliary member joining step, the metal member 1 and the auxiliary member 4 may be joined by welding.

(5) Second preliminary process
When the first main joining process is completed, the metal members 1 and 1 are turned over, and the second preliminary process is executed. The second preliminary process according to the present embodiment includes a pilot hole forming process of forming a pilot hole (not shown) at the friction stirring start position in the second main joining process. In the second preliminary process, temporary joining may be performed on the abutting portion J1 from the back surface 13 side of the metal members 1 and 1.

(6) Second Main Joining Step When the second preliminary step is completed, as shown in FIG. 9 (a), the rotating tool F for main joining is used to connect the metal member 1 to the abutting portion J1. A second main joining process is performed in which friction stir welding is performed from the back surface 13 side. In the second main joining step, work substantially equivalent to the first main joining step is performed from the back surface 13 side. Also in the second main joining step, only the stirring pin F2 is inserted into the metal member 1 while the connecting portion F1 of the main welding rotary tool F and the metal member 1 are separated from each other. When the friction stir welding is performed on the abutting portion J1, the friction stir is performed while the stirring pin F2 of the main welding rotating tool F is inserted into the plasticizing region W1 formed in the first main joining step.

(7) Second repair process
When the second main joining step is completed, the second repairing step is performed on the plasticized region W2 formed in the metal member 1 by the second main joining step. In the second repair process, work substantially equivalent to the first repair process is performed from the back surface 13 side. As shown in FIG. 9B, when the second repair process is performed, the entire auxiliary member 4 is covered with the two plasticized regions w3. Finally, the first tab material 2 and the second tab material 3 are cut from the metal members 1 and 1.

  According to the friction stir welding described above, when the friction stir welding is performed, the portion to be brought into contact with the metal members 1 and 1 is only the stirring pin F2 of the rotating tool F for main joining, so that the metal member can be compared with the conventional one. 1 and 1 and the main rotating tool F can be reduced, and the load applied to the friction stirrer can be reduced. Since the load applied to the friction stirrer is reduced, the stirring pin F2 can be inserted to a deep position of the metal members 1 and 1.

  In addition, by bringing the plasticized region W1 formed in the first main joining step into contact with the plasticized region W2 formed in the second main joining step, the total length in the thickness direction of the abutting portion J1 is obtained. Since friction stir welding can be performed, airtightness and watertightness can be improved. Further, in the present embodiment, when performing the second main joining process, since the friction stir welding is performed while the stirring pin F2 is in contact with the plasticizing region W1, even if there is a joint defect in the plasticizing region W1. The junction defect can be repaired.

  Moreover, even if a level | step difference is formed in the surface 12 or the back surface 13 of the metal member 1 by the 1st main joining process and the 2nd main joining process, the surface 12 or the back surface 13 of the metal member 1 is performed by performing a repair process. Can be flattened. Further, in the auxiliary member joining step, at least the metal member 1 and the auxiliary member 4 may be joined, but the auxiliary member 4 is plasticized by joining the entire auxiliary member 4 as in the present embodiment. Covered with w2 and w3, the airtightness and watertightness can be further enhanced.

  Moreover, when the temporary joining process of the butt | matching part J1 is performed, when performing this joining process, it can prevent that the metal members 1 and 1 leave | separate. Further, by providing the tab material, it is easy to insert and remove the rotary tool, and by providing a pilot hole in the tab material, it is possible to reduce the press-fitting resistance when the rotary tool is pushed.

  Although the embodiments of the present invention have been described above, design changes can be made without departing from the spirit of the present invention. For example, FIG. 10 is a diagram showing a modification of the repair process, in which (a) shows a groove forming process and (b) shows a build-up welding process. In the repair process, the auxiliary member 4 may be replaced by overlay welding. That is, as shown in FIG. 10 (a), after forming the groove M on the plasticized region W1 formed in the first main joining step, overlay welding is performed on the groove M. Good. Thereby, since the weld metal N is filled in the groove M, the surface 12 of the metal members 1 and 1 can be flattened. The concave groove forming step may be omitted.

  Moreover, although the temporary joining process was performed by friction stir welding in this embodiment, welding may be used. In the repairing process using the auxiliary member 4, the temporary bonding rotary tool G is used. However, when the auxiliary member 4 is thick, a larger rotating tool may be used. Moreover, you may join the auxiliary member 4 and the metal member 1 by welding.

  In the embodiment, three types of main welding rotary tools FA, FB, and FC having different dimensions are used, and the rotational speed of each rotary tool and the conditions of the pilot holes are changed, so that the surface 12 of the metal member 1 that is a flat aluminum alloy is used. Was moved by a predetermined length, and the cross section of the formed plasticized region was observed. Reference numerals and dimensions in the embodiments refer to FIG. 1 as appropriate. At the time of friction stir welding, the rotating tool for main welding was rotated to the right, the connecting portion F1 of the rotating tool for main welding and the metal member 1 were separated, and only the stirring pin F2 was inserted into the metal member 1.

<Example 1>
FIG. 11 is a cross-sectional view of the conditions of Example 1 and each plasticized region. In Example 1, the test body NO. The test was performed under each condition using the three test bodies 1 to 3. The outer diameter X1 (see (a) of FIG. 1) of the connecting portion F1 of the main joining rotating tool FA is 140 mm, and the thickness X2 is 40 mm. The length Y1 of the stirring pin F2 is 55 mm, the proximal end outer diameter Y2 is 32 mm, and the distal end outer diameter Y3 is 16 mm. On the outer peripheral surface of the agitation pin F2, a left-handed spiral groove F3 is engraved with a depth of 2 mm and a pitch of 2 mm.

  FIG. 12 is a cross-sectional view for explaining the first embodiment. The insertion depth dimension t1 is the length from the tip of the pushed stirring pin F2 to the surface 12. The pilot hole K has a cylindrical shape, and is set to have a diameter t2 = 20 mm and a depth t3 = 45 mm.

  As shown in FIG. 11, the specimen NO. In 1 to 3, no bonding defect was observed. A step P is formed on the surface 12 of the metal member 1. The step P becomes deeper toward the left side in the traveling direction of the main rotating tool for welding FA. The level difference P is considered to be formed when metal plasticized by friction stir welding is scattered or becomes burrs L and flows out to the outside. The burrs L are concentrated on the right side in the traveling direction of the main rotating tool FA. In the welding rotary tool FA, the change in the rotation speed of the tool is not significantly affected.

<Example 2>
FIG. 13 is a cross-sectional view of the conditions of Example 2 and each plasticized region. In Example 2, the test body NO. The test was performed under each condition using four specimens of 4 to 7. The outer diameter X1 (see FIG. 1A) of the connecting portion F1 of the main rotating tool FB is 140 mm, and the thickness X2 is 55 mm. The length Y1 of the stirring pin F2 is 77 mm, the proximal end outer diameter Y2 is 38 mm, and the distal end outer diameter Y3 is 16 mm. On the outer peripheral surface of the agitation pin F2, a left-handed spiral groove F3 is engraved with a depth of 2 mm and a pitch of 2 mm.

  FIG. 14 is a cross-sectional view for explaining the second embodiment. The insertion depth dimension t4 is the length from the tip of the agitated stirring pin F2 to the surface 12. The pilot hole K includes a wide portion K1 and a narrow portion K2 formed on the bottom surface of the wide portion K1. Both the wide part K1 and the narrow part K2 have a cylindrical shape. The diameter of the wide part K1 is t5, the depth dimension is t7, the diameter of the narrow part K2 is t6, and the depth dimension is t8.

  As shown in FIG. In any of Nos. 4 to 7, no junction defect was observed. A step P is formed on the surface 12 of the metal member 1. The level difference P is considered to be formed when metal plasticized by friction stir welding is scattered or becomes burrs L and flows out to the outside. NO. 4 and 5, it can be seen that the metal pattern is different between the upper part and the lower part of the plasticized region W. This is NO. In 4 and 5, the rotation speed of the tool is high, so it is considered that the upper metal of the plastic fluidized metal tends to become high temperature. On the other hand, NO. In 6 and 7, since the number of rotations of the tool is low, the pattern of the plasticized region W is almost uniform. Specimen NO. In step 7, the level difference P was relatively small.

<Example 3>
FIG. 15 is a cross-sectional view of the conditions of Example 3 and each plasticized region. In Example 3, the test was performed under the respective conditions using the four test bodies 8 to 11 using the main rotating tool for bonding FC. The outer diameter X1 (see FIG. 1A) of the connecting portion F1 of the welding rotary tool FC is 140 mm, and the thickness X2 is 45 mm. The length Y1 of the stirring pin F2 is 157 mm, the proximal end outer diameter Y2 is 54.7 mm, and the distal end outer diameter Y3 is 16 mm. On the outer peripheral surface of the agitation pin F2, a left-handed spiral groove F3 is engraved with a depth of 2 mm and a pitch of 2 mm.

  As shown in FIG. Bonding defects were observed in the portion of the sign Q of 8 to 10 (left side in the traveling direction of the rotary tool). A relatively large step P is formed on the surface 12 of the metal member 1. The level difference P is considered to be formed when the metal plasticized by friction stir welding is scattered or becomes burrs and flows out. On the other hand, specimen NO. In No. 11, the insertion depth was shortened (approximately half of the length of the stirring pin F2 was inserted), so there was almost no step.

DESCRIPTION OF SYMBOLS 1 Metal member 2 1st tab material 3 2nd tab material 4 Auxiliary member 12 Front surface 13 Back surface F Rotating tool for main joining F1 Connection part F2 Stirring pin G Temporary joining rotating tool G1 Shoulder part G2 Stirring pin J1-J4 Butting part K Pilot hole M Concave groove W1 Plasticized region w1-w3 Plasticized region

Claims (5)

A friction stir welding method for joining two metal members using a rotary tool provided with a stirring pin and connected to a rotating shaft of a friction stirrer,
The state where the agitating pin that has been rotated is inserted into the abutting portion between the metal members, and only the agitating pin of the rotating tool among the friction agitating device and the rotating tool is brought into contact with the metal member to generate frictional heat. A main joining process in which friction stir welding is performed,
After the main joining step, a groove forming step of forming a groove by cutting the surface of the plasticized region surrounded by the step formed in the main joining step;
After the concave groove forming step, an arranging step of arranging an auxiliary member in the concave groove;
After the arrangement step, an auxiliary member joining step for joining the metal member and the auxiliary member,
Including
A spiral groove is engraved on the outer peripheral surface of the stirring pin,
The temporary joining rotary tool used in the auxiliary member joining step is composed of a shoulder portion and a stirring pin,
The shoulder portion has a columnar shape and is a portion that is connected to the rotating shaft of the friction stirrer and is a portion that holds the plastic fluidized metal,
In the auxiliary member joining step, the temporary stirring joining rotary tool is moved while pushing the lower end surface of the shoulder portion into the surfaces of the metal member and the auxiliary member. A friction stir welding method for joining two metal members using a rotary tool provided with a stirring pin and connected to a rotating shaft of a friction stirrer,
The state where the agitating pin that has been rotated is inserted into the abutting portion between the metal members, and only the agitating pin of the rotating tool among the friction agitating device and the rotating tool is brought into contact with the metal member to generate frictional heat. A main joining process in which friction stir welding is performed,
After the main joining step, a groove forming step of forming a groove by cutting the surface of the plasticized region surrounded by the step formed in the main joining step;
After the concave groove forming step, an arranging step of arranging an auxiliary member in the concave groove;
After the arrangement step, an auxiliary member joining step for joining the metal member and the auxiliary member,
Including
A spiral groove is engraved on the outer peripheral surface of the stirring pin,
In the main joining process,
A first main joining step of performing friction stir welding from the surface side of the metal member;
A second main joining step of performing friction stir welding from the back side of the metal member,
Bringing the plasticized region formed in the first main joining step into contact with the plasticized region formed in the second main joining step;
The temporary joining rotary tool used in the auxiliary member joining step is composed of a shoulder portion and a stirring pin,
The shoulder portion has a columnar shape and is a portion that is connected to the rotating shaft of the friction stirrer and is a portion that holds the plastic fluidized metal,
In the auxiliary member joining step, the temporary stirring joining rotary tool is moved while pushing the lower end surface of the shoulder portion into the surfaces of the metal member and the auxiliary member.   The friction stir welding method according to claim 1 or 2, further comprising a temporary bonding step of temporarily bonding the metal members before performing the main bonding step.   The tab material is disposed beside the abutting portion and a pilot hole is provided in the tab material, and then the main joining step is performed by inserting a stirring pin of the rotary tool into the pilot hole. The friction stir welding method according to any one of claims 3 to 3.   The two metal members are placed on a frame of a friction stirrer before the main joining step, and the two metal members are restrained immovably using a jig. 5. The friction stir welding method according to any one of items 4.