JP6699530B2 - Joining method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for joining metal members using friction stirring.

  Friction stir welding (FSW) is known as a method of joining metal members to each other. Friction stir welding moves the rotating tool along the abutting part of the metal members while rotating it, and the frictional heat between the rotating tool and the metal member causes the metal of the abutting part to plastically flow, thereby solidifying the metal members. It is what is joined. It should be noted that the rotary tool is generally one in which a stirring pin (probe) is provided in a protruding manner on the lower end surface of a cylindrical shoulder portion.

  For example, Patent Literature 1 discloses a technique of joining a metallic cylindrical member and a lid member that covers the opening of the cylindrical member by friction stirring. In this technique, the inner corner portion formed by the tubular member and the lid member is joined by welding.

International Publication No. 2009/081731A1 Pamphlet

  It is difficult to join the inner corners of the tubular member and the lid member because the working space is limited. In particular, when friction stir welding is performed on the inner corner, since the shoulder portion contacts the cylindrical member and the lid member in the conventional rotating tool, there is a problem that the stirring pin cannot be inserted to a deep position. .. Further, since the plastically fluidized metal cannot be pressed by the shoulder portion, the metal overflows to the outside, and there is a risk of insufficient metal and poor bonding.

  From such a viewpoint, it is an object of the present invention to provide a joining method capable of reliably joining a tubular member and a lid member.

In order to solve such a problem, the first aspect of the present invention is a joining method for joining a metal tubular member and a metal lid member that covers an opening of the tubular member, wherein the tubular member An abutting step of abutting the tubular member and the lid member to form an abutting portion so that an outer peripheral surface of the member and an outer peripheral surface of the lid member are flush with each other; and the tubular member with respect to the abutting portion. An external friction stir step of performing friction stir from the outside, and a plate-shaped auxiliary member so as to make surface contact with the tubular member or the lid member at an inner corner formed by the tubular member and the lid member. Arranging step, and the rotating tool is relatively moved along the inner corner with only the stirring pin of the rotating tool in contact with the cylindrical member, the lid member and the auxiliary member, An inner friction stirring step of performing friction stirring from the inside of the cylindrical member, and before the outer friction stirring step and the inner friction stirring step, only the stirring pin from the outside of the cylindrical member to the cylindrical member and The method may further include a temporary bonding step of performing spot temporary bonding to the abutting portion while being in contact with the lid member .

According to this joining method, even if only the stirring pin is inserted into the abutting portion and friction stirring is performed from the inside of the tubular member, the auxiliary member is arranged at the inner corner, so that the metal shortage can be eliminated. You can As a result, the inner corners of the tubular member and the lid member can be reliably joined together. Further, it is possible to prevent the opening of the butted portion during the outer friction stir process and the inner friction stir process. Further, thermal distortion due to friction stir welding can be suppressed, and processing time for temporary joining can be shortened.

Furthermore, the removal step of removing the auxiliary member which burrs are formed by friction stir welding from previous SL tubular member or the lid member, preferably further comprising. Further, in the inside friction stir step, it is preferable to set the welding conditions so that burrs generated by the friction stir welding are formed on the auxiliary member. According to this joining method, the burr can be easily removed together with the auxiliary member.

  In order to solve the above problems, a second aspect of the present invention is a joining method for joining a metallic tubular member and a metallic lid member that covers an opening of the tubular member, wherein the tubular member An abutting step of forming the abutting portion by abutting the tubular member and the lid member so that the outer peripheral surface and the outer peripheral surface of the lid member are flush with each other; and an outer side of the tubular member with respect to the abutting portion. An outer friction stirring step of performing friction stirring from the above, and an auxiliary member having an L-shaped cross section so as to make surface contact with the tubular member and the lid member at an inner corner formed by the tubular member and the lid member. And a relative movement of the rotary tool along the inner corner with only the stirring pin of the rotary tool in contact with the tubular member, the lid member and the auxiliary member, An inner friction stir step of performing friction stir from the inside of the strip-shaped member.

  According to such a joining method, even if only the stirring pin is inserted into the abutting portion and friction stirring is performed from the inside of the tubular member, the auxiliary member is arranged at the inner corner, so that the metal shortage can be eliminated. You can As a result, the inner corners of the tubular member and the lid member can be reliably joined together.

  In the present invention, before the outer friction stirring step and the inner friction stirring step, with respect to the abutting portion, only the stirring pin is in contact with the tubular member and the lid member from the outside of the tubular member. It is preferable to include a temporary bonding step of performing spot temporary bonding by means of the above. Further, before the outer friction stirring step and the inner friction stirring step, a temporary joining step of performing spot temporary joining to the butt portion by TIG, MIG or laser welding may be included. According to such a joining method, it is possible to prevent the opening of the abutting portion during the outer friction stirring process and the inner friction stirring process. Further, thermal strain due to friction stir welding can be suppressed, and the processing time for temporary joining can be shortened.

Furthermore, the removal step of removing the auxiliary member which burr is formed while being separated by the friction stir welding at said inner friction stir process before Symbol cylindrical member and the lid member, preferably further comprising. According to such a joining method, the burr can be easily removed together with the auxiliary member.

  According to the joining method of the present invention, the tubular member and the lid member can be reliably joined.

(A) is a side view showing a welding rotary tool of the present embodiment, and (b) is a schematic sectional view showing a welding mode of the welding rotary tool. (A) is an exploded perspective view showing a structure concerning a first embodiment, and (b) is a perspective view showing a temporary joining process concerning a first embodiment. (A) is a perspective view showing an outer friction stir process according to the first embodiment, and (b) is a sectional view showing an outer friction stir process according to the first embodiment. It is a perspective view showing an arrangement process concerning a first embodiment. (A) is a perspective view showing an inner friction stir process according to the first embodiment, and (b) is a sectional view showing an inner friction stir process according to the first embodiment. (A) is an exploded perspective view showing a structure concerning a second embodiment, and (b) is a perspective view showing a temporary joining process concerning a second embodiment. (A) is a perspective view which shows the outer side friction stirring process which concerns on 2nd embodiment, (b) is sectional drawing which shows the outer side friction stirring process which concerns on 2nd embodiment. (A) is a perspective view which shows the arrangement|positioning process which concerns on 2nd embodiment, (b) is sectional drawing which shows the arrangement|positioning process which concerns on 2nd embodiment. (A) is a perspective view showing an inner friction stir process according to the second embodiment, and (b) is a sectional view showing an inner friction stir process according to the second embodiment. (A) is sectional drawing which shows the welding process which concerns on 3rd embodiment, (b) is sectional drawing which shows the outer side friction stirring process and inner side friction stirring process which concern on 3rd embodiment. (A) is sectional drawing which shows the arrangement|positioning process which concerns on 4th embodiment, (b) is sectional drawing which shows the outer side friction stirring process and inner side friction stirring process which concern on 4th embodiment.

[First embodiment]
A joining method according to the first embodiment of the present invention will be described in detail with reference to the drawings. First, the rotating tool for joining used in this embodiment will be described.

  As shown in FIG. 1A, the welding rotary tool F includes a connecting portion F1 and a stirring pin F2. The rotary tool F for joining is formed of tool steel, for example. The connecting portion F1 is a portion connected to the rotating shaft D of the friction stirrer shown in FIG. The connecting portion F1 has a columnar shape and has screw holes B, B for fastening bolts.

  The stirring pin F2 depends 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. The length of the stirring pin F2 is larger than the plate thicknesses of the tubular member 2 and the lid member 3 described later. A spiral groove F3 is engraved on the outer peripheral surface of the stirring pin F2. In this embodiment, in order to rotate the joining rotary tool F clockwise, the spiral groove F3 is formed counterclockwise from the base end toward the tip. In other words, the spiral groove F3 is formed counterclockwise when viewed from above when tracing the spiral groove F3 from the base end toward the tip.

  When rotating the welding rotary tool F counterclockwise, it is preferable to form the spiral groove F3 in a clockwise direction from the base end toward the tip. In other words, the spiral groove F3 in this case is formed clockwise when viewed from above when tracing the spiral groove F3 from the base end to the tip. By setting the spiral groove F3 in this manner, the metal fluidized during frictional stirring is guided to the tip end side of the stirring pin F2 by the spiral groove F3. Thereby, the amount of metal overflowing to the outside of the structure (the tubular member 2 and the lid member 3 described later) can be reduced.

  As shown in FIG. 1B, when friction stir welding is performed using the welding rotary tool F, only the rotated stirring pin F2 is inserted into the structure, and the structure and the connecting portion F1 are separated from each other. Move while moving. In other words, the friction stir welding is performed with the base end of the stirring pin F2 exposed. A plasticized region W1 (or a plasticized region W2) is formed on the movement locus of the welding rotary tool F by hardening the metal that has been frictionally stirred.

  Next, the joining method of this embodiment will be described. In the joining method according to the present embodiment, as shown in FIG. 2A, a case where the tubular member 2 and the lid member 3 are joined by friction stirring to form the structure 1 is illustrated.

  The tubular member 2 is a metal member and has a rectangular frame-shaped cross section. The material of the tubular member 2 may be appropriately selected from frictionally stirable metal materials such as aluminum, aluminum alloys, copper, copper alloys, titanium, titanium alloys, magnesium and magnesium alloys. The tubular member 2 is formed with a constant plate thickness.

  The lid member 3 is a metal member and has a rectangular plate shape. The lid member 3 is a member that covers the opening of the tubular member 2. The material of the lid member 3 may be appropriately selected from metal materials capable of friction stirring, but in the present embodiment, the same material as the tubular member 2 is used.

  In the joining method according to the present embodiment, a butting step, a temporary joining step, an outer friction stirring step, an arranging step, an inner friction stirring step, and a removing step are performed.

  The butting step is a step of covering the opening of the tubular member 2 with the lid member 3 and butting the tubular member 2 and the lid member 3 together. More specifically, in the butting process, the end surface 2a of the tubular member 2 and the back surface 3b of the lid member 3 are butted, and the outer peripheral surface 2c of the tubular member 2 and the outer peripheral surface 3c of the lid member 3 are flush with each other. Butt so that A butt portion J1 (see FIG. 2B) is formed by the butt step.

  The temporary joining step is a step of temporarily joining the abutting portion J1. As shown in FIG. 2B, in the temporary joining step, the butting portion J1 is temporarily joined by using the joining rotary tool F or another rotary tool. Only the agitating pin F2 of the rotated welding rotary tool F is brought into contact with the abutting portion J1 to perform spot temporary attachment. In the temporary joining process, only the stirring pin F2 is shallowly pushed into the abutting portion J1 at a predetermined interval. In this embodiment, since the spiral groove F3 is formed in the counterclockwise direction from the base end toward the tip, the welding rotary tool F is rotated clockwise. When the spiral groove F3 is formed in the clockwise direction, it is preferable to rotate the welding rotary tool F counterclockwise. A plasticized region W0 is formed at the imprint of the stirring pin F2.

  The outer friction stir step is a step in which the butting portion J1 is friction stir welded from the outside of the tubular member 2 in earnest. In the outer friction stir step, as shown in FIG. 3A, the rotating rotating tool F for joining is inserted at an arbitrary start position s1 on the abutting portion J1. The insertion depth of the welding rotary tool F may be set appropriately, but in the present embodiment, it is inserted up to about half the plate thickness of the tubular member 2. The rotation center axis of the joining rotary tool F is inserted so as to be perpendicular to the joining surfaces (the outer peripheral surface 2c of the tubular member 2 and the outer peripheral surface 3c of the lid member 3). Then, in the outer friction stir step, the butting portion J1 is traced and relatively moved. A plasticized region W1 is formed on the movement locus of the welding rotary tool F. In the outer friction stir step, only the stirring pin F2 is brought into contact with the cylindrical member 2 and the lid member 3, and the stirring is performed with the base end side of the stirring pin F2 exposed.

  After the joining rotary tool F makes one round along the abutting portion J1, the starting position s1 is passed to overlap the start end and the end of the plasticized region W1, and then the joining rotary tool F is moved to the tubular member 2 and It is detached from the lid member 3. In addition, when the extraction mark of the stirring pin F2 remains after the joining rotary tool F is detached, the repair process may be performed by performing overlay welding on the extraction mark to repair the extraction mark. As a result, the joint surface can be finished neatly.

  Alternatively, the welding rotary tool F may be detached while gradually decreasing the insertion depth of the welding rotary tool F. As a result, it is possible to eliminate the drawing mark of the stirring pin F2 or reduce the drawing mark.

  In the temporary joining process, the outer friction stirring process, and the inner friction stirring process described below, for example, the joining rotary tool F may be attached to the tip of a robot arm equipped with a rotation driving means such as a spindle unit to perform friction stirring. it can. Thereby, the angle of the rotation center axis of the welding rotary tool F can be easily changed.

  The arranging step is a step of arranging the auxiliary member 10 at an inner corner portion formed by the tubular member 2 and the lid member 3. As shown in FIG. 4, the auxiliary member 10 has a long flat plate shape. The auxiliary member 10 is annularly arranged along the inner corner. The auxiliary member 10 is arranged so as to come into surface contact with the back surface 3b of the lid member 3 and have one side in the width direction contacting the inner peripheral surface 2b of the tubular member 2. The material of the auxiliary member 10 may be appropriately selected from metal materials capable of friction stirring, but in the present embodiment, the same material as the tubular member 2 is used. The size (width, plate thickness, etc.) of the auxiliary member 10 may be set to such an extent that metal does not run short at the joint portion and burrs do not remain excessively when an inner friction stir process described later is performed. preferable. In this embodiment, the linear auxiliary member 10 is provided for each side of the inner corner, but a plate member for each side may be integrated.

  The inner friction stir process is a process of friction stir welding from the inside of the tubular member 2 to the auxiliary member 10 and the abutting portion J1 in earnest. In the inner friction stir step, as shown in FIG. 5A, the joining rotary tool F rotated to an arbitrary start position s2 at the end (inner corner side) of the auxiliary member 10 on the tubular member 2 side is rotated. Insert until reaching the abutting portion J1. In the inner friction stirring step, as shown in FIG. 5B, the insertion is performed so that the angle formed by the rotation center axis of the welding rotary tool F and the back surface 3b of the lid member 3 is about 45°. Then, while keeping the angle, the joining rotary tool F is relatively moved by tracing the auxiliary member 10 along the inner corner. In the inner friction stirring step, only the stirring pin F2 is brought into contact with the cylindrical member 2, the lid member 3 and the auxiliary member 10, and friction stirring is performed with the base end side of the stirring pin F2 exposed. A plasticized region W2 is formed on the movement locus of the welding rotary tool F. A burr V is formed on the auxiliary member 10 side of the plasticized region W2.

  The insertion depth of the welding rotary tool F may be set appropriately, but as in the present embodiment, the plasticized region W2 and the plasticized region W1 formed in the outer friction stir process overlap. Is preferred. By doing so, the entire abutting portion J1 in the depth direction can be friction stir welded, and the joint strength, watertightness, and airtightness can be enhanced.

  After the welding rotary tool F makes one round at the inner corner along the abutting portion J1, the start position s2 is passed to overlap the start end and the end of the plasticized region W2, and then the welding rotary tool F is moved. The tubular member 2 and the lid member 3 are separated from each other. When removing the welding rotary tool F, a repair process may be performed as in the outer friction stir process, or the welding rotary tool F may be released by gradually decreasing the insertion depth. Good.

  The insertion angle of the welding rotary tool F may be changed so that the angle formed by the rotation center axis of the welding rotary tool F and the back surface 3b of the lid member 3 is smaller than 45°. By doing so, it is possible to plastically fluidize to a deeper position of the abutting portion J1. After the inner friction stir process is completed, burrs and the like generated in the outer friction stir process and the inner friction stir process are cut off. Thereby, the surface of the structure 1 can be finished cleanly.

  In the present embodiment, the rotation direction, rotation speed, and traveling direction of the welding rotary tool F are set so that the burr V generated by friction stir welding is formed on the auxiliary member 10 side. The relationship between the rotation direction/speed and the advancing direction of the welding rotary tool F and the position where the burr V is generated will be described below.

  When the rotation speed of the welding rotary tool F is slow, the shear side (advancing side) of the rotary tool is compared with the flow side (retroating side: the moving speed of the rotary tool is subtracted from the tangential speed at the outer circumference of the rotary tool). Since the temperature of the plastic flow material is more likely to increase on the side where the moving speed of the rotary tool is added to the tangential speed on the outer circumference, more burr V tends to occur on the shear side outside the plasticizing region W. On the other hand, when the rotation speed of the welding rotary tool F is higher, the temperature of the plastic flow material is higher on the shear side, but since the rotation speed is higher, more burrs V are generated on the flow side outside the plasticizing region W. There is a tendency.

  That is, in the present embodiment, the rotation speed of the joining rotation tool F is set to be high, and the joining rotation tool F is rotated clockwise while being advanced to the back side in the drawing surface direction in FIG. 5B. As a result, the auxiliary member 10 side becomes the flow side, and the burr V can be collected on the auxiliary member 10. Further, by setting the rotation speed of the welding rotary tool F to be high, the moving speed (feed speed) of the welding rotary tool F can be increased. Thereby, the joining cycle can be shortened.

  Which side in the traveling direction of the rotary tool the burrs occur depends on the welding conditions. The joining conditions include the rotational speed of the rotary tool, the rotational direction, the advancing direction, the advancing speed (feeding speed), the inclination angle (taper angle) of the stirring pin, the materials of the tubular member 2, the lid member 3 and the auxiliary member 10, It is determined by the combination of each element such as the thickness of the auxiliary member 10. That is, the threshold values of the high rotation speed and the low rotation speed of the rotary tool are determined by other factors.

  The removing step is a step of removing burrs generated by friction stir welding. In the removing step, the remaining auxiliary member 10 is bent and cut off to remove the burr V together with the auxiliary member 10. The removing step may use a cutting device or the like, but in the present embodiment, it is performed manually.

  According to the joining method according to the present embodiment described above, even if friction stirring is performed in a state where only the stirring pin F2 is in contact with the tubular member 2 and the lid member 3 from the inside of the tubular member 2, the auxiliary member 10 can be used. At the same time, friction stirring is performed, so that metal shortage can be resolved. As a result, the inner corners of the tubular member 2 and the lid member 3 can be reliably joined together. Further, since the outer friction stir process is performed first, the inner friction stir process can be stably performed.

  Further, by performing the temporary joining process, it is possible to prevent the opening of the abutting portion J1 during the outer friction stirring process. Furthermore, since spot temporary joining is performed, thermal distortion due to friction stir welding can be suppressed and processing time for temporary joining can be shortened as compared with the case where temporary joining is performed on the entire butt portion J1.

  Further, according to the present embodiment, since only the stirring pin F2 is inserted into the tubular member 2, the lid member 3 and the auxiliary member 10, the load on the friction stirrer is reduced as compared with the case where the shoulder portion of the rotary tool is pushed. In addition, the operability of the welding rotary tool F is improved. Further, since the load on the friction stirrer can be reduced, it is possible to join the deep position of the abutting portion J1 without applying a large load to the friction stirrer.

  Further, in the present embodiment, since the burr V is formed on the side of the auxiliary member 10 and the burr V is integrally removed by removing the auxiliary member 10, the burr V can be easily removed. Further, in the present embodiment, since the same welding rotary tool F is used in the temporary welding process, the outer friction stirring process, and the inner friction stirring process, it is not necessary to replace the rotation tool for each process. Therefore, the labor can be saved. Of course, another rotating tool may be used depending on the case.

  The first embodiment is not limited to the above-mentioned form. For example, when the outer friction stir process shown in FIG. 3 is performed, the tab material is arranged, the tab material is temporarily joined to the tubular member 2 and the lid member 3, and the rotary tool F for joining is started to the tab material. The position and the end position may be set. By using the tab material, the start position and the end position of the welding rotary tool F can be easily set. Further, there is no need to perform a repair process for the extraction mark of the rotary tool F for joining.

  Further, in the present embodiment, the auxiliary member 10 is in surface contact with the lid member 3, but the present invention is not limited to this. The auxiliary member may make surface contact with the inner peripheral surface of the tubular member. In this case, a long plate-shaped plate material is erected and arranged along the inner peripheral surface of the tubular member.

  Furthermore, although the tubular member 2 has a rectangular tubular shape in the present embodiment, it may have a tubular shape, an elliptic tubular shape, or another polygonal tubular shape. Further, the temporary joining step may be omitted. Further, at least one of the tubular member 2 and the lid member 3 may be provided with a step to be abutted.

  Further, in the present embodiment, spot temporary joining is performed on the abutting portion J1 with only the stirring pin F2 in contact with the tubular member 2 and the lid member 3, but the present invention is not limited to this. For example, spot temporary joining may be performed by TIG, MIG, or laser welding.

[Second embodiment]
Next, a joining method according to the second embodiment of the present invention will be described. The joining method according to the second embodiment differs from the first embodiment mainly in that the tubular member 2A and the lid member 3A are cylindrical and that the shape of the auxiliary member 11 is L-shaped in cross section.

  In the joining method according to this embodiment, as shown in FIG. 6A, the cylindrical member 2A and the lid member 3A are joined by friction stirring to form the structure 1A. The tubular member 2A has a cylindrical shape. The lid member 3A has a disc shape. The outer diameter of the lid member 3A is equal to the outer diameter of the tubular member 2A.

  In the joining method according to the present embodiment, a butting step, a temporary joining step, an outer friction stirring step, an auxiliary member disposing step, an inner friction stirring step, and a removing step are performed.

  The abutting step is a step of covering the opening of the tubular member 2A with the lid member 3A and abutting the tubular member 2A and the lid member 3A. More specifically, in the butting process, the end surface 2a of the tubular member 2A and the back surface 3b of the lid member 3A are butted against each other, and the outer peripheral surface 2c of the tubular member 2A and the outer peripheral surface 3c of the lid member 3A are flush with each other. Butt so that The abutting portion J1 (see FIG. 6B) is formed by the abutting step.

  The temporary joining step is a step of temporarily joining the abutting portion J1. As shown in FIG. 6B, in the temporary joining step, the butting portion J1 is temporarily joined by using the joining rotary tool F or another rotary tool. Only the agitating pin F2 of the rotated welding rotary tool F is brought into contact with the abutting portion J1 to perform spot temporary attachment. In the temporary joining process, only the stirring pin F2 is shallowly pushed into the abutting portion J1 at a predetermined interval. In this embodiment, since the spiral groove F3 is formed in the counterclockwise direction from the base end toward the tip, the welding rotary tool F is rotated clockwise. When the spiral groove F3 is formed in the clockwise direction, it is preferable to rotate the welding rotary tool F counterclockwise. A plasticized region W0 is formed at the imprint of the stirring pin F2.

  The outer side friction stir step is a step of full-scale friction stir welding of the abutting portion J1 from the outside of the tubular member 2A. In the outer friction stir step, as shown in FIG. 7A, the rotating rotary welding tool F is inserted at an arbitrary start position s1 of the abutting portion J1. The rotation center axis of the welding rotation tool F is inserted so as to overlap the normal line of the start position s1. The insertion depth of the welding rotary tool F may be set as appropriate, but in the present embodiment, it is inserted up to about half the plate thickness of the tubular member 2A. Then, in the outer friction stir process, the welding rotary tool F is relatively moved so as to trace the butting portion J1. In this embodiment, the position of the welding rotary tool F is fixed, and the tubular member 2A and the lid member 3A are rotated around the central axis. A plasticized region W1 is formed on the movement locus of the welding rotary tool F. In the outer friction stir step, only the stirring pin F2 is brought into contact with the cylindrical member 2A and the lid member 3A, and the friction stirring is performed with the base end side of the stirring pin F2 exposed.

  After the abutting portion J1 is rotated once with the welding rotary tool F, the start position s1 is passed to overlap the start end and the end of the plasticized region W1, and then the welding rotary tool F is attached to the tubular member 2A and the lid member. Remove from 3A. When detaching the welding rotary tool F, the repairing step may be performed as in the first embodiment, or the welding rotating tool F may be detached by gradually decreasing the insertion depth. Good.

  In the temporary joining process, the outer friction stirring process, and the inner friction stirring process described below, for example, the joining rotary tool F may be attached to the tip of a robot arm equipped with a rotation driving means such as a spindle unit to perform friction stirring. it can. Thereby, the angle of the rotation center axis of the welding rotary tool F can be easily changed.

  The arranging step is a step of arranging the auxiliary member 11 at the inner corner of the tubular member 2A and the lid member 3A, as shown in FIGS. 8(a) and 8(b). The auxiliary member 11 is a ring-shaped member having an L-shaped cross section. The auxiliary member 11 includes an annular bottom plate portion 11a and a cylindrical side plate portion 11b. The side plate portion 11b rises from the outer peripheral edge of the bottom plate portion 11a. The outer diameter of the auxiliary member 11 (the outer diameter of the side plate portion 11b) is equal to the inner diameter of the tubular member 2A. The material of the auxiliary member 11 is preferably the same as that of the tubular member 2A and the lid member 3A.

  In the arranging step, as shown in FIG. 8B, the auxiliary member 11 is arranged at the inner corners of the tubular member 2A and the lid member 3A so as to cover the abutting portion J1. More specifically, the outer peripheral surface of the side plate portion 11b of the auxiliary member 11 is brought into surface contact with the inner peripheral surface 2b of the tubular member 2A, and the bottom plate portion 11a of the auxiliary member 11 is brought into surface contact with the back surface 3b of the lid member 3A. The size (width, plate thickness, etc.) of the auxiliary member 11 may be set to such a degree that metal does not become insufficient at the joint portion and burrs do not remain excessively when the inner friction stir step described later is performed. preferable.

  The inner friction stir step is a step of full-scale friction stir welding from the inside of the tubular member 2A to the auxiliary member 11 and the abutting portion J1. In the inner friction stir step, as shown in FIG. 9(a), the joining rotation is performed by rotating the inner corner of the auxiliary member 11 (the intersection of the bottom plate portion 11a and the side plate portion 11b) to an arbitrary start position s2. Insert the tool F to the position where it reaches the abutting portion J1. In the inner friction stir step, as shown in FIG. 9B, the insertion is performed such that the angle formed by the rotation center axis of the welding rotary tool F and the back surface 3b of the lid member 3A is about 45°. Then, while keeping the angle, the auxiliary rotating member F is relatively moved by tracing the auxiliary member 11 along the inner corner. In the inner friction stir step, only the stirring pin F2 is brought into contact with the cylindrical member 2A, the lid member 3A and the auxiliary member 11, and friction stirring is performed with the base end side of the stirring pin F2 exposed. A plasticized region W2 is formed on the movement locus of the welding rotary tool F. Burrs V are formed on both sides in the width direction of the plasticized region W2.

  The insertion depth of the welding rotary tool F may be set appropriately, but as in the present embodiment, the plasticized region W2 and the plasticized region W1 formed in the outer friction stir process overlap. Is preferred. By doing so, the entire abutting portion J1 in the depth direction can be friction stir welded, and the joint strength, watertightness, and airtightness can be enhanced.

  After the abutting portion J1 is rotated once by the welding rotary tool F, the start position s2 is passed to overlap the start end and the end of the plasticized region W2, and then the welding rotary tool F is moved to the tubular member 2A and the lid member. Remove from 3A. When removing the welding rotary tool F, the repairing step may be performed as in the first embodiment, or the welding rotary tool F may be released by gradually decreasing the insertion depth. Good.

  The insertion angle of the welding rotary tool F may be changed so that the angle formed by the rotation center axis of the welding rotary tool F and the back surface 3b of the lid member 3A is smaller than 45°. By doing so, it is possible to plastically fluidize the butt portion J1 to a deeper position. After the inner friction stir process is completed, burrs and the like generated in the outer friction stir process and the inner friction stir process are cut off. Thereby, the surface of the structure 1A can be finished cleanly.

  In the present embodiment, the rotation direction, rotation speed, traveling direction, etc. of the welding rotary tool F are set so that the burrs V generated by friction stir welding are formed on both sides in the width direction of the plasticized region W2. In FIG. 9B, the burr V is evenly generated on both sides in the width direction of the plasticized region W2, but it may be biased to one side. In the present embodiment, the burr V may be generated at either the bottom plate portion 11a side or the side plate portion 11b side of the auxiliary member 11.

  The removing step is a step of removing burrs generated by friction stir welding. In the removal step, the bottom plate portion 11a and the side plate portion 11b of the remaining auxiliary member 11 are cut off by bending them so that the burr V is removed together with the auxiliary member 11. The removing step may use a cutting device or the like, but in the present embodiment, it is performed manually.

  According to the joining method according to the present embodiment described above, even if friction stirring is performed in a state where only the stirring pin F2 is in contact with the tubular member 2A and the lid member 3A from the inside of the tubular member 2A, the auxiliary member 11 can be used. At the same time, friction stirring is performed, so that the metal shortage in the inner corner can be eliminated. As a result, the inner corners of the tubular member 2A and the lid member 3A can be reliably joined together. Further, since the outer friction stir process is performed first, the disposing process can be stably performed.

  Further, by performing the temporary joining process, it is possible to prevent the opening of the abutting portion J1 during the outer friction stirring process. Further, according to the present embodiment, since only the stirring pin F2 is inserted into the cylindrical member 2A, the lid member 3A and the auxiliary member 11, the load applied to the friction stirrer is reduced as compared with the case of pushing the shoulder portion of the rotary tool. In addition, the operability of the welding rotary tool F is improved. Further, since the load on the friction stirrer can be reduced, it is possible to join the deep position of the abutting portion J1 without applying a large load to the friction stirrer.

  Further, in the present embodiment, the burr V is integrally removed by removing the auxiliary member 11, so that the burr V can be easily removed.

  The second embodiment is not limited to the above-mentioned form. In the outer friction stir process of the present embodiment, the welding rotary tool F is used. However, a rotary tool having a shoulder portion and a stirring pin is used, and the shoulder portion is attached to the cylindrical member 2A and the lid member 3A by about several millimeters. You may push in and perform friction stir welding.

Further, in the present embodiment, after the outer friction stirring step, the auxiliary member arranging step of arranging the auxiliary member 11 in the inner corner portion formed by the tubular member 2A and the lid member 3A is performed. Prior to the friction stir step, an arrangement step of arranging the auxiliary member 11 at the inner corner formed by the tubular member 2A and the lid member 3A may be performed.
Further, although the tubular member 2A is cylindrical in this embodiment, it may be elliptic or polygonal. Further, the temporary joining step may be omitted. Further, at least one of the tubular member 2A and the lid member 3A may be provided with a step and abutted against each other.

[Third embodiment]
Next, a joining method according to the third embodiment of the present invention will be described. The joining method according to the third embodiment is a form similar to that of the first embodiment, and the order of steps is mainly different from that of the first embodiment. The third embodiment will be described focusing on the parts different from the first embodiment.

  In the joining method according to the third embodiment, a butting step, a temporary joining step, an arranging step, an inner friction stirring step, a removing step, and an outer friction stirring step are performed in this order.

  The abutting step and the temporary joining step are the same as those in the first embodiment, and therefore their explanations are omitted. As shown in FIG. 10A, in the disposing step, the auxiliary member 10 is disposed at the inner corner of the tubular member 2 and the lid member 3. The auxiliary member 10 has a long flat plate shape. The auxiliary member 10 is annularly arranged along the inner corner. The auxiliary member 10 is arranged so as to come into surface contact with the back surface 3b of the lid member 3 and have one side in the width direction contacting the inner peripheral surface 2b of the tubular member 2. The material of the auxiliary member 10 is preferably the same as that of the tubular member 2 and the lid member 3. It is preferable that the size of the auxiliary member 10 is set to such a degree that metal does not become insufficient in the joint portion and burrs do not remain excessively when the inner friction stir step described later is performed.

  In the inside friction stir process, the insertion is performed so that the angle formed by the rotation center axis of the welding rotary tool F and the back surface 3b of the lid member 3 is about 45°. Then, the welding rotary tool F is relatively moved by tracing the auxiliary member 10 while keeping the angle. In the inner friction stirring step, only the stirring pin F2 is brought into contact with the cylindrical member 2, the lid member 3 and the auxiliary member 10, and friction stirring is performed with the base end side of the stirring pin F2 exposed. A plasticized region W1 is formed on the movement locus of the welding rotary tool F.

  In the removing step, burrs generated by friction stir welding are removed. In the removing step, the remaining auxiliary member 10 is bent and cut off to remove the burr V together with the auxiliary member 10. The removing step may use a cutting device or the like, but in the present embodiment, it is performed manually.

  In the outer friction stir process, friction stir welding is performed from the outside of the tubular member 2 to the butted portion J1 in the same manner as the outer friction stir process of the first embodiment. In the outer friction stir process, as shown in FIG. 10B, the insertion depth of the welding rotary tool F is adjusted so that the plasticized region W2 and the plasticized region W1 formed in the outer friction stir process come into contact with each other. Is preferably set. As a result, the entire abutting portion J1 in the depth direction can be friction stir welded, and the joint strength, watertightness, and airtightness can be improved.

  Also according to the present embodiment described above, it is possible to obtain substantially the same effects as the first embodiment.

[Fourth Embodiment]
Next, a joining method according to the fourth embodiment of the present invention will be described. The joining method according to the fourth embodiment is a form similar to the second embodiment, and the order of steps is mainly different from that in the second embodiment. The fourth embodiment will be described focusing on the parts different from the second embodiment.

  In the joining method according to the fourth embodiment, a butting step, a temporary joining step, an auxiliary member disposing step, an inner friction stir step, a removing step, and an outer friction stir step are performed in this order.

  The abutting step and the temporary joining step are the same as those in the second embodiment, and therefore their explanations are omitted. As shown in FIG. 11A, in the lid member arranging step, the auxiliary member 11 is arranged at the inner corners of the tubular member 2A and the lid member 3A so as to cover the abutting portion J1 in the same manner as in the second embodiment. To do. In the present embodiment, the placement step is performed after the temporary joining step, so that the placement step can be performed stably.

  In the inner friction stir process, friction stir welding is performed from the inside of the tubular member 2A to the auxiliary member 11 and the abutting portion J1 in the same manner as the inner friction stir process of the second embodiment. As shown in FIG. 11B, a plasticized region W1 is formed in the abutting portion J1 by the inner friction stir process.

  In the outer friction stir step, friction stir welding is performed from the outside of the tubular member 2A to the butted portion J1 in the same manner as the outer friction stir step of the second embodiment. In the outer side friction stir process, as shown in FIG. 11B, the insertion depth of the welding rotary tool F is adjusted so that the plasticized region W2 and the plasticized region W1 formed in the outer friction stir process come into contact with each other. Is preferably set. As a result, the entire abutting portion J1 in the depth direction can be friction stir welded, and the joint strength, watertightness, and airtightness can be improved.

  Also according to the present embodiment described above, substantially the same effects as those of the second embodiment can be obtained.

1 Structure 1A Structure 2 Cylindrical member 2A Cylindrical member 3 Lid member 3A Lid member 10 Auxiliary member 11 Auxiliary member F Rotating tool for joining (rotating tool)
F2 Stirring pin J1 Butt W0 Plasticized region W1 Plasticized region W2 Plasticized region

Claims (7)

A joining method for joining a metallic tubular member and a metallic lid member that covers an opening of the tubular member,
A butting step of forming a butting portion by butting the tubular member and the lid member so that the outer circumferential surface of the tubular member and the outer circumferential surface of the lid member are flush with each other;
An outer friction stirring step of performing friction stirring on the butting portion from the outside of the tubular member;
An arranging step of arranging a plate-shaped auxiliary member so as to make surface contact with the tubular member or the lid member in an inner corner portion formed by the tubular member and the lid member,
Friction stir from the inside of the tubular member by relatively moving the rotary tool along the inner corner with only the stirring pin of the rotating tool in contact with the tubular member, the lid member and the auxiliary member. And an inner friction stir step of performing
Prior to the outer friction stir step and the inner friction stir step, spot temporary joining is performed on the abutting portion in a state where only the stirring pin is in contact with the tubular member and the lid member from the outside of the tubular member. A joining method further comprising a temporary joining step of performing . The bonding method according to claim 1, wherein the removing step of removing the auxiliary member which burrs are formed by friction stir welding from previous SL tubular member or the lid member, further comprising. The joining method according to claim 2, wherein, in the inner friction stir step, the joining conditions are set such that burrs generated by the friction stir welding are formed on the auxiliary member. A joining method for joining a metallic tubular member and a metallic lid member that covers an opening of the tubular member,
A butting step of forming a butting portion by butting the tubular member and the lid member so that the outer circumferential surface of the tubular member and the outer circumferential surface of the lid member are flush with each other;
An outer friction stirring step of performing friction stirring on the butting portion from the outside of the tubular member;
An arranging step of arranging an auxiliary member having an L-shaped cross section so as to make surface contact with the tubular member and the lid member at an inner corner formed by the tubular member and the lid member;
Friction stir from the inside of the tubular member by relatively moving the rotary tool along the inner corner with only the stirring pin of the rotating tool in contact with the tubular member, the lid member and the auxiliary member. An inner friction stir step of performing the step of: Prior to the outer friction stir step and the inner friction stir step, spot temporary joining is performed on the abutting portion with only the stirring pin being in contact with the tubular member and the lid member from the outside of the tubular member. The joining method according to claim 4, further comprising a temporary joining step of performing. The joining according to claim 4, further comprising a temporary joining step of performing spot temporary joining to the butt portion by TIG, MIG or laser welding before the outer friction stirring step and the inner friction stirring step. Method. Claim 4, characterized in that the removing step of removing the auxiliary member burrs while being separated is formed by friction stir welding at said inner friction stir process before Symbol tubular member and said lid member, further comprising To the bonding method according to claim 6 .

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