JP5794290B2 - Joining method - Google Patents

Description

  The present invention relates to a method for joining metal members.

  Friction stir welding (FSW = Friction Stir Welding) is known as a method for joining metal members. Friction stir welding is a process in which a rotating tool is rotated and moved along the abutting portion between metal members, and the metal at the abutting portion is plastically flowed by frictional heat between the rotating tool and the metal member, thereby solidifying the metal members together. It is what is joined.

  Many inventions have been proposed in which metal members are joined to each other using this friction stir welding. In Patent Document 1, a cover plate is arranged on the upper end of a frame member that has a metal frame shape, and a rotary tool is pushed in from the upper surface side of the cover plate to plastically fluidize a part of the frame member and the cover plate. Have been disclosed.

  FIG. 15 is a cross-sectional view of a principal part illustrating a conventional method of manufacturing a structure in a stepwise manner, and shows an opposite frame member and an end of a cover plate. As shown in FIG. 15A, in the conventional structure manufacturing method, first, step portions 102 and 102 are formed on the end portion of the frame member 101a and the end portion of the cover plate 101b, and the step portions 102 and 102 are formed. As shown in FIG. 15B, the abutting portion J1 is formed. Then, the rotating tool can be pushed in from the cover plate 101b side and integrated by performing friction stir welding on the abutting portion J1. In the abutting portion J1, the plastic member that has plastic flowed is hardened to form a plasticized region W.

Japanese Patent Laid-Open No. 11-300481 (FIG. 1)

  According to the conventional structure manufacturing method, there is a problem that when the rotary tool is detached from the structure after the friction stir welding, a punch hole remains in the structure by the stirring pin of the rotary tool.

  From such a viewpoint, an object of the present invention is to provide a joining method in which a punched hole does not remain in a joined metal member.

In order to solve the above-described problems, the present invention provides a joining method for joining a pair of metal members having a rectangular parallelepiped shape, and includes a flat side surface of one metal member and a flat end surface of the other metal member. An abutting step for abutting so that a corner is formed, and an end surface of one of the metal members and one side surface of the other metal member that is flush with the end surface with respect to the abutting portion formed in the abutting step An outer surface joining step of performing friction stir using a rotating tool for main welding from the outer surface, and an end surface of one of the metal members formed in the outer surface joining step when a stirring pin of the rotating tool for main welding is removed Or, provided on one side surface of the other metal member, the side surface of the one metal member and the other side surface and the other side with respect to the punched hole repairing process for repairing the punched hole and the butted portion formed in the butting process of And Uchisumi part welding step of performing overlay welding to the inner corner portion formed by the other side of the serial metallic member, characterized in that it comprises a.

  According to this joining method, it is possible to prevent a punched hole from remaining in the metal member.

  The punching hole repairing step includes a filling metal member inserting step of filling the punching hole with a filling metal member, and a friction by moving a rotary tool along a joint between the metal member and the filling metal member. It is preferable to include a repair joining step of performing stir welding.

  Moreover, it is preferable that the repair welding process which fills a weld metal to the punched hole formed when the stirring pin of the said rotary tool was removed by the said repair joining process is included.

  According to the joining method according to the present invention, no through hole remains in the joined metal member.

It is the perspective view which showed the structure which concerns on 1st embodiment, (a) is the surface side, (b) is the figure seen from the back surface side. (A) is the side view which showed the rotary tool for temporary joining, (b) is the side view which showed the rotary tool for this joining. It is the figure which showed the manufacturing method of the structure which concerns on 1st embodiment, Comprising: (a) is the perspective view which showed the butt | matching process, (b) is the top view which showed the tab material arrangement | positioning process. It is the figure which showed the manufacturing method of the structure which concerns on 1st embodiment, Comprising: (a) is the top view which showed the surface joining process, (b) The perspective view which showed the surface joining process and the back surface joining process FIG. It is the top view which showed the outer surface joining process of the manufacturing method of the structure which concerns on 1st embodiment. It is II sectional drawing of FIG. 5, Comprising: (a) shows before joining, (b) shows after joining. It is the top view which showed the punch hole repair process of the manufacturing method of the structure which concerns on 1st embodiment. It is sectional drawing which showed the through hole repair process of the manufacturing method of the structure which concerns on 1st embodiment. It is the perspective view which showed the step part formation process and cover plate arrangement | positioning process of the manufacturing method of the structure which concerns on 1st embodiment. It is the top view which showed the cover plate fixing process of the manufacturing method of the structure which concerns on 1st embodiment in steps. It is sectional drawing which showed the cover plate fixing process of the manufacturing method of the structure which concerns on 1st embodiment. It is the figure which showed the 1st modification, Comprising: (a) is a perspective view, (b) is sectional drawing. It is the top view which showed the 2nd modification, Comprising: (a) is the figure which formed the notch part, (b) is the figure which performed welding. It is the perspective view which showed the 3rd modification, Comprising: (a) shows a ditch | groove formation process, (b) shows an outer surface welding process. It is principal part sectional drawing which showed the manufacturing method of the conventional structure in steps, Comprising: The frame member and the edge part of a cover board which oppose are shown.

[First embodiment]
A first embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, the structure of the structure manufactured by the structure manufacturing method according to the present invention will be described.

  As shown to (a) and (b) of FIG. 1, the structure 1 which concerns on this embodiment has the frame member 2 which exhibits frame shape, and the cover plate 3 which covers opening by the side of the back surface 16 of the frame member 2. As shown in FIG. Have. The opening on one side of the frame member 2 is closed by the lid plate 3. The frame member 2 has four metal members 2a, 2b, 2c, and 2d that end to each other, and are integrally formed by friction stir welding. The lid plate 3 is a metal member having a plate shape. As shown in FIG. 1B, the outer surface 32 of the cover plate 3 is formed flush with the rear surface 16 of the frame member 2. The frame member 2 and the lid plate 3 are joined by a plasticizing region W5 formed at the abutting portion J5 between the frame member 2 and the lid plate 3.

  Next, the structure manufacturing method will be described in detail. The structure manufacturing method according to the present embodiment includes (1) a frame member forming step, (2) a stepped portion forming step, (3) a cover plate arranging step, (4) a cover plate fixing step, and (5) an inner corner portion. Perform the welding process.

  First, referring to the drawings, a small rotary tool used in the temporary joining process (hereinafter referred to as “temporary joining rotary tool F”) and a large rotary tool used in the main joining process (hereinafter referred to as “main joining rotary tool”). G ”) will be described in detail.

  A temporary tool F for temporary joining shown in FIG. 2A is made of a metal material harder than the frame member 2 such as tool steel, and projects into a shoulder portion F1 having a columnar shape and a lower end surface F11 of the shoulder portion F1. A stirring pin (probe) F2 is provided. The dimensions and shape of the temporary joining rotary tool F may be set according to the material, thickness, etc. of the frame member 2, but at least from the final joining rotary tool G (see FIG. 2B). Also make it small. This makes it possible to perform temporary bonding with a load smaller than that of the main bonding, so that it is possible to reduce the load applied to the friction stirrer at the time of temporary bonding. Since the moving speed (feeding speed) can be made faster than the moving speed of the main joining rotary tool G, the working time and cost required for temporary joining can be reduced.

The lower end surface F11 of the shoulder portion F1 is a portion that plays a role of pressing the plastic fluidized metal and preventing scattering to the surroundings, and is formed in a concave shape in this embodiment. There is no particular limitation on the size of the outer diameter X ₁ of the shoulder portion F1, in this embodiment, is smaller than the outer diameter Y ₁ of the shoulder portion G1 of the joining rotation tool G.

The stirring pin F2 hangs down from the center of the lower end surface F11 of the shoulder portion F1, and is formed into a tapered truncated cone shape in this embodiment. In addition, a stirring blade engraved in a spiral shape is formed on the peripheral surface of the stirring pin F2. There is no particular limitation on the size of the outer diameter of the stirring pin F2, in the present embodiment, the maximum outer diameter (upper diameter) X ₂ is the maximum outer diameter of the stirring pin G2 of the rotary tool G for the joint (upper end diameter) Y ₂ smaller than, and the minimum outer diameter (bottom diameter) _{X 3} is smaller than the minimum outer diameter (bottom diameter) _{Y 3} of the stirring pin G2. The length L _A of the stirring pin F2 may be appropriately set according to the thickness of the frame member 2, but is preferably at least smaller than the length L _B of the stirring pin G2 of the main rotating tool G for joining. .

  2B is made of a metal material harder than the frame member 2 such as tool steel, and protrudes into a shoulder portion G1 having a cylindrical shape and a lower end surface G11 of the shoulder portion G1. It comprises a stirring pin (probe) G2 provided.

The lower end surface G11 of the shoulder portion G1 is formed in a concave shape like the temporary joining rotary tool F. The stirring pin G2 hangs down from the center of the lower end surface G11 of the shoulder portion G1, and is formed into a tapered truncated cone shape in this embodiment. In addition, a stirring blade engraved in a spiral shape is formed on the peripheral surface of the stirring pin G2. The length L _B of the stirring pin G2 may be set appropriately according to the thickness of the frame member 2.

(1) Frame member forming step In the frame member forming step, as shown in FIGS. 3 and 4, a frame member having a frame shape is formed. In the frame member forming process, a butt process, a tab material arranging process, and a main joining process are performed.

  In the abutting step, as shown in FIGS. 3A and 3B, the ends of the metal members 2a, 2b, 2c, and 2d are butted together. The metal members 2a, 2b, 2c, and 2d are members having a rectangular parallelepiped shape, and are made of a metal material capable of friction stirring such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy. In this embodiment, each metal member is formed of a metal material having the same composition. The thickness of each metal member is the same.

  In the abutting step, as shown in FIGS. 3A and 3B, the end surface 15c of the metal member 2c and the end surface 14d of the metal member 2d are butted against both ends of the inner surface 12a of the metal member 2a, respectively. In each butted portion, a butting portion J1 and a butting portion J4 are formed, respectively. The end surface 14a of the metal member 2a and the outer surface 13c of the metal member 2c are formed flush with each other. Further, the end surface 15a of the metal member 2a and the outer surface 13d of the metal member 2d are formed flush with each other.

  In the abutting step, the end surface 14c of the metal member 2c and the end surface 15d of the metal member 2d are butted against both ends of the inner surface 12b of the metal member 2b. A butt portion J2 and a butt portion J3 are formed in each butt portion. The end surface 15b of the metal member 2b and the outer surface 13c of the metal member 2c are formed flush with each other. Further, the end surface 14b of the metal member 2d and the outer surface 13d of the metal member 2d are formed flush with each other.

  In the abutting step, the surfaces 11a, 11b, 11c, and 11d of the metal members 2a, 2b, 2c, and 2d are formed flush with each other. Further, the back surfaces 16a, 16b, 16c, 16d of the metal members 2a, 2b, 2c, 2d are formed flush with each other. A corner formed by two adjacent surfaces of the inner surfaces 12a, 12b, 12c, and 12d is defined as an inner corner. A member formed in a frame shape by the abutting process is referred to as a bonded metal member 10.

  Of the metal member 10 to be bonded, the surface constituted by the four surfaces (11a, 11b, 11c, 11d) is the surface 11, and the surface constituted by the four inner surfaces (12a, 12b, 12c, 12d) is the inner peripheral surface. 12, the outer surface 13 and the four back surfaces (16a, 16b, 16c, 16d) are composed of four outer surfaces (13a, 13b, 13c, 13d) and four end surfaces (14a, 15a, 14b, 15b). A surface to be configured is referred to as a back surface 16. The bonded metal member 10 is opened to the front surface 11 side and the back surface 16 side, respectively.

  In the tab material arranging step, as shown in FIG. 3B, a pair of tab materials are arranged at the abutting portions J1 to J4 appearing in the metal member 10 to be joined. Tab members 21 and 22 are attached to both sides of the abutting portion J1. The tab members 21 and 22 have a rectangular parallelepiped shape and have the same composition as the bonded metal member 10. The front and back surfaces of the tab members 21 and 22 are formed flush with the front surface 11 and the back surface 16 of the bonded metal member 10. The tab material 22 is in contact with the inner surface 12a of the metal member 2a and the inner surface 12c of the metal member 2c. The to-be-joined metal member 10 and the tab materials 21 and 22 are joined by welding. The tab material is a member for which a start position and an end position are set in a friction stirring operation described later. The shape and number of tab members are not limited to the present embodiment.

  In the main joining step, as shown in FIGS. 4 to 8, friction stir welding is performed on each butt portion of the metal member 10 to be joined. In the main joining step, a surface joining step for performing friction stir welding from the front surface 11 side of the metal member 10 to be joined, a back surface joining step for performing friction stir welding from the back surface 16 side of the metal member 10 to be joined, and the metal member 10 to be joined. And an outer surface joining step of performing friction stir welding from the outer peripheral surface 13 side. Further, the outer surface joining step includes a punch hole repairing step.

  In the surface bonding step, as shown in FIG. 4A, the main rotation tool G is inserted from the surface 11 side of the metal member 10 to be bonded, and the friction stir welding is performed on each abutting portion. For example, for the abutting portion J <b> 1, the start position SM <b> 1 is set on the surface of the tab material 21, and the end position EM <b> 1 is set on the surface of the tab material 22. After inserting the main welding rotary tool G rotated to the right at the start position SM1, the main welding rotary tool G is moved along the abutting portion J1, and the main welding rotary tool G is detached at the end position EM1. As a result, a plasticized region W1a is formed in the abutting portion J1. The plasticization region includes both a state in which the rotating tool is heated by frictional heat and is actually plasticized, and a state in which the rotating tool passes and returns to room temperature.

  Similarly, friction stir welding is also performed on the abutting portions J2, J3, and J4. Plasticized regions W2a, W3a, and W4a are formed in the abutting portions J2, J3, and J4, respectively.

  In the back surface joining step, as shown in FIG. 4B, after reversing the front and back of the metal member 10 to be bonded, the main rotating tool G (see FIG. 2) from the back surface 16 side of the metal member 10 to be bonded. b)) is inserted, and friction stir welding is performed on each of the abutting portions J1 to J4. Since the back surface joining process is the same as the surface joining process except for the front and back surfaces of the metal member 10 to be joined, detailed description thereof is omitted. By the back surface joining step, plasticized regions W1b, W2b, W3b, and W4b are formed in the respective abutting portions J1, J2, J3, and J4 that appear on the back surface 16 of the metal member 10 to be joined.

  When the back surface joining process is completed, the tab material is removed from the metal member 10 to be joined. As shown in FIG. 4B, when the back surface joining process is completed, an unplasticized region that is not frictionally stirred remains between the plasticized region W1a and the plasticized region W1b formed in the abutting portion J1. To do. Similarly, unplasticized regions that are not frictionally stirred remain in the abutting portions J2 to J4.

  In the outer surface joining step, friction stir welding is performed on each of the abutting portions J1 to J4 appearing on the outer peripheral surface 13 of the metal member 10 to be joined. That is, friction stir welding is performed on the unplasticized region remaining on the outer peripheral surface 13. For example, as shown in FIG. 5, in the butt portion J1, an unplasticized region that is not frictionally stirred remains between the plasticized region W1a and the plasticized region W1b. That is, there is a minute gap that continues from the inner peripheral surface 12 to the outer peripheral surface 13 of the bonded metal member 10 at the abutting portion J1. In the outer surface joining step, the gap is covered with a plasticized region formed by friction stir welding.

  As shown in FIG. 5, a start position SM2 and an end position EM2 are set on the outer peripheral surface 13 at a position separated by a predetermined distance from the abutting portion J1. In the present embodiment, the start position SM2 is set on the plasticizing region W1b side and the end position EM2 is set on the plasticizing region W1a side, but the present invention is not limited to this. The main welding rotary tool G is inserted into the start position SM2, the main welding rotary tool G is moved in the direction of the abutting portion J1, and then the plasticizing region W1b and the main welding rotary tool G are brought into contact with each other. And after moving along the butt | matching part J1 and carrying out friction stirring of the unplasticization area | region, the plasticization area | region W1a and the rotation tool G for main joining are made to contact. Then, the main joining rotary tool G is detached at the end position EM2. A plasticized region W1c is formed on the outer peripheral surface 13 by the outer surface joining step.

  Here, FIG. 6 is a cross-sectional view taken along the line II in FIG. 5, where (a) shows before joining and (b) shows after joining. As shown in FIGS. 6A and 6B, in the outer surface joining step, the end position EM2 is set on the outer peripheral surface 13 of the metal member 10 to be joined. Is formed with a hole Q1. Therefore, in this embodiment, a hole repair process is performed to close the hole Q1.

  The punch hole repair process is a process of closing the punch hole Q1 that is inevitably formed in the outer periphery joining process. In the punch hole repairing step, a filling metal member insertion step (see FIG. 6B) for filling the filling metal member H into the punch hole Q1 formed in the outer peripheral surface 13 of the metal member 10 to be joined, A repair joining process in which friction agitation is performed on the abutting portion J6 of the metal member 10 and the filling metal member H (see FIG. 7), and welding is performed to a through hole Q2 formed on the surface of the filling metal member H in the repair joining process. And a repair welding process for filling the metal K (see FIG. 8).

  As shown in FIG. 6 (b), the filling metal member insertion step includes a hole formed in the outer peripheral surface 13 of the metal member 10 to be joined when the main rotating tool G is detached in the outer surface joining step. In this step, a filling metal member H having the same shape as the hole Q1 is inserted into the hole Q1 to fill the hole Q1. In this embodiment, the filling metal member H is formed of a metal material having the same composition as the metal member 10 to be joined, but any metal material that can be frictionally stirred may be used.

  In the repair joining process, as shown in FIG. 7, friction is applied to the abutting portion J <b> 6 between the metal member to be joined 10 and the filling metal member H using a temporary joining rotary tool F (see FIG. 2A). Stir welding is performed. In the repair joining step, the stirring pin F2 of the temporary joining rotary tool F (see FIG. 2A) is placed at the friction stirring start position s1 set on the joint between the metal member 10 to be joined and the filling metal member H. And the temporary joining rotary tool F is moved along the joint between the metal member to be joined 10 and the filling metal member H, so that frictional stirring is performed over the entire circumference of the abutting portion J6. The plasticized region w1 is formed by the repair joining process.

  In this embodiment, after performing frictional stirring over the entire circumference of the abutting portion J6, the frictional stirring end position e1 (set to the center position of the surface of the filling metal member H is set to the temporary bonding rotary tool F). It is moved to the friction stirring end position EM2) in the outer surface joining step, and the temporary joining rotary tool F is detached from the end position e1. As described above, when the stirring pin F2 is separated upward at the end position e1, a hole Q2 having substantially the same shape as the stirring pin F2 is formed at the end position e1 (see FIG. 8).

  Here, in this embodiment, in order to friction stir the abutting portion J6 between the metal member to be bonded 10 and the filling metal member H, the temporary bonding rotary tool F used in the temporary bonding step is used. Other rotary tools may be used as long as the stirring pin can be moved circumferentially along the joint between the metal member 10 and the filling metal member H.

  In the repair welding process, as shown in FIG. 8, the weld metal K is filled in the punch hole Q2 by performing overlay welding such as MIG welding in the punch hole Q2 formed on the surface of the metal member H for filling. To do.

  The repair welding process is not limited to MIG welding, and other known welding may be performed. Moreover, although the welding material may differ from the to-be-joined metal member 10, in this embodiment, the same material is used. In the repair welding process, it is desirable to cut away the weld metal K that is raised from the outer peripheral surface 13 of the metal member 10 to be joined after the weld metal K is filled in the punch hole Q2.

  The above-described outer surface joining step is also performed on the abutting portions J2, J3, and J4 to seal the unplasticized region remaining on the outer peripheral surface 13 of the metal member 10 to be joined. The frame member 2 is formed by the above process.

  The main joining step is configured as described above in the present embodiment, but may be in another form. For example, a pilot hole P1 (see FIG. 2B) may be formed at the start position of each friction stir welding in order to reduce the frictional resistance when the main rotating tool G is inserted. In addition, before performing the friction stir welding using the main rotating tool G, the temporary bonding is performed to each abutting portion using the temporary rotating tool F (see FIG. 2A) (temporary bonding process). May be performed. Thereby, this joining process can be performed in the state where each metal member was temporarily attached.

  Further, when the plasticized region formed in the front surface bonding step and the plasticized region formed in the back surface bonding step overlap each other, the non-plasticized region does not remain on the outer peripheral surface 13 of the frame member 2, and thus the outer surface The joining step may be omitted.

  Moreover, before performing an outer surface joining process, a pair of tab material may be attached to the surface 11 and the back surface 16 of the to-be-joined metal member 10, and the start position and end position of friction stirring may be set to the said tab material. According to this, the hole repair process can be omitted.

(2) Stepped portion forming step In the stepped portion forming step, a stepped portion 40 is formed on the inner peripheral edge of the opening opened on the back surface 16 side of the frame member 2 as shown in FIG. The step portion 40 is formed in a shape on which the cover plate 3 is placed without a gap. The step portion 40 includes a step portion bottom surface 41 and four step portion side surfaces 42 erected perpendicularly to the step portion bottom surface 41. What is necessary is just to set the width | variety of the step part bottom face 41 suitably considering the magnitude | size of the rotation tool G for this joining. The height of the step side surface 42 is formed to be equal to the thickness of the lid plate 3.

(3) Lid Plate Arrangement Step In the lid plate arrangement step, the lid plate 3 is arranged on the stepped portion 40. As shown in FIG. 9 and FIG. 10A, when the cover plate 3 is disposed on the stepped portion 40, the back surface 31 of the cover plate 3 and the stepped bottom surface 41 of the stepped portion 40 are brought into contact with each other. The four four side surfaces 33 and the four stepped side surfaces 42 of the stepped portion 40 are butted together to form a butted portion J5. The abutting portion J5 is formed to have an L shape in cross section and a rectangular shape in plan view. The outer surface 32 of the cover plate 3 and the back surface 16 of the frame member 2 are flush with each other. When the lid plate 3 is disposed on the stepped portion 40, a corner portion constituted by the inner surface 31 of the lid plate 3 and the inner peripheral surface 12 of the frame member 2 is defined as an inner corner portion.

  Although the step portion 40 is formed in this embodiment, the step portion 40 is not necessarily formed. For example, the inner peripheral surface 12 of the frame member 2 and the four side surfaces 33 of the cover plate 3 may be abutted to form a butt portion.

(4) Lid plate fixing process In the lid plate fixing process, a main joining process in which friction stir welding is performed on the abutting portion J5 and a through hole repair process in which the through hole is repaired are performed.

  In the main joining step, as shown in FIGS. 10 and 11, the friction stir welding is performed from the outer surface 32 side of the cover plate 3 to the abutting portion J5. In the main joining step, as shown in FIG. 10A, the friction stir welding start position SM3 is set on the back surface 16 of the frame member 2 outside the abutting portion J5. In the main joining step, the main welding rotation tool G rotated to the right is inserted into the start position SM3, and the main welding rotation tool G is moved toward the abutting portion J5. As shown, it is moved along the abutting portion J5. In the main joining step, as shown in FIG. 11, the axial center of the main welding rotary tool G and the abutting portion J5 appearing on the back surface 16 are moved along the abutting portion J5.

  By the main joining process, the plasticized region W5 is formed along the abutting portion J5. After rotating the main welding rotary tool G along the abutting portion J5, after further moving the main welding rotary tool G along the starting end portion 51 (see FIG. 10A) of the first week of friction stirring. As shown in FIG. 10B, the main joining rotary tool G is detached at the end position EM <b> 3 set outside the abutting portion J <b> 5 on the back surface 16 of the frame member 2.

  Here, in the plasticized region formed by friction stir welding, the shear side (the relative speed of the outer periphery of the rotating tool with respect to the welded portion is the magnitude of the moving speed to the size of the tangential speed on the outer periphery of the rotating tool. On the side where the value is added), it is considered that the metal is vigorously stirred and softened at a high temperature to be easily discharged as burrs. For this reason, there is a possibility that a tunnel-like cavity defect is formed because the shear side lacks metal. In the main joining step, the main joining rotary tool G is rotated to the right while the cover plate 3 is moved to the right in the traveling direction, that is, moved clockwise with respect to the opening of the frame member 2. Therefore, even if a cavity defect occurs, it is formed at a position separated from the hollow portion of the frame member 2.

  By the way, when the main rotating tool G is rotated counterclockwise, it is preferably moved counterclockwise with respect to the opening of the frame member 2.

  In the punch hole repair process, repair is performed to block a punch hole (not shown) remaining at the end position EM3. Since the hole repair process is equivalent to the above-described form, detailed description is omitted.

  It should be noted that a tab material that contacts the outer peripheral surface 13 of the frame member 2 may be used to set the friction stirring start position and end position on the tab material so that no punch holes remain in the frame member 2.

  As shown in FIG. 11, in the main joining step, the axial center of the main welding rotary tool G is positioned at a portion (overlapping portion) where the inner surface 31 of the cover plate 3 and the step bottom surface 41 are abutted. In this manner, friction stir welding may be performed. In addition, before the main joining process is performed using the main joining rotating tool G, the temporary joining process may be performed on the abutting portion J5 using the temporary joining rotating tool F.

(5) Inner Corner Welding Process In the inner corner welding process, as shown in FIG. 1A, a frame member inner corner welding process for welding the inner corner of the frame member, and the frame member And a lid plate inner corner welding process for performing welding on the inner corner constituted by the lid plate.

  In the frame member inner corner welding step, welding is performed on the inner corner formed at the corner of the inner peripheral surface 12 of the frame member 2. For example, as shown in FIG. 1A, the abutting portion J1 appears at the inner corner formed by the inner surface 12a of the metal member 2a and the inner surface 12c of the metal member 2c. That is, an unplasticized region remains between the plasticized region W1a and the plasticized region W1b in the inner corner. In the frame member inner corner welding process, overlay welding such as MIG welding is performed on the unplasticized region, and the unplasticized region is sealed with the weld metal T. The weld metal T is preferably formed so as to overlap the plasticized regions W1a and W1b. Similarly, overlay welding is also performed on the inner corner portions related to the abutting portions J2, J3, and J4 to cover the unplasticized region with the weld metal T.

  The frame member inner corner welding step may be performed in the frame member forming step described above. Further, when the inner corner is sealed by the plasticized region formed in the above-described front surface joining step and back surface joining step, the frame member inner corner portion welding step may be omitted.

  In the lid plate inner corner welding step, as shown in FIG. 1A, welding is performed on the inner corner formed by the inner peripheral surface 12 of the frame member 2 and the inner surface 31 of the lid plate 3. In the present embodiment, overlay welding such as MIG welding is performed to cover the inner corner with the weld metal T. In the lid plate inner corner welding step, welding is performed along the inner circumferential surface 12 over the entire circumference.

  By performing the above steps, the structure 1 is formed as shown in FIGS.

  According to the manufacturing method of the structure according to the present embodiment described above, the structure is obtained by performing the welding process from the inner corner (front surface 11 side) of the structure 1 and the cover plate fixing process from the outer side (back surface 16 side). Since heat is input at the inner corner and the outer side of the body 1 and heat shrinkage occurs on each of the outer surface 32 side and the inner surface 31 side of the cover plate 3, warping of the cover plate 3 can be corrected. Moreover, since each abutting part which appears inside the structure 1 can be sealed by covering the inner corner with the weld metal, the airtightness and the watertightness can be enhanced.

  Further, according to the inner corner welding step, the work can be performed relatively easily as compared with the case where the friction stir welding is performed on the inner corner of the structure 1, so that the work efficiency can be increased. In addition, either the inner corner welding step and the lid plate fixing step may be performed first, but by performing the lid plate fixing step first as in the present embodiment, the frame member 2 and the lid plate 3 Even if a defect is formed in the inner corner, the defect can be repaired in the inner corner welding process. On the other hand, if the inner corner welding process is performed first, the cover plate fixing process can be performed with the cover plate 3 temporarily attached to the frame member 2.

  In the frame member forming step, the outer surface joining step is performed on the abutting portions J1 to J4 appearing on the outer peripheral surface 13 of the frame member 2, and the inner corners of the frame member are formed on the abutting portions J1 to J4 appearing on the inner peripheral surface 12. By performing the welding process, each of the abutting portions J1 to J4 can be reliably sealed. Thereby, the airtightness of the structure 1 and watertightness can be improved more. Moreover, it can prevent that a punch hole remains in the structure 1 by performing a punch hole repair process.

[First modification]
Next, a first modification of the present invention will be described. In the first modification, as shown in FIG. 12A, a notch 60 is formed on the inner peripheral edge of the step bottom surface 41 of the frame member 2. The notch 60 is a notch having a rectangular shape in cross section, and is a portion filled with weld metal. In the present embodiment, the cutout portion 60 has a rectangular shape in cross section, but may have another shape. As shown in FIG. 12B, by arranging the cover plate 3 on the frame member 2, a concave groove 61 is formed by the notch 60 and the inner surface 31 of the cover plate 3. The concave groove 61 is formed in a frame shape along the inner peripheral surface 12.

  In the above-described inner corner welding process of the cover plate, overlay welding is performed on the groove 61 to fill the weld metal. The weld metal protruding from the groove 61 is preferably cut so as to be flush with the inner peripheral surface 12. By forming the concave groove 61 as in the first modification, the welding operation can be easily performed because the concave groove 61 can be filled with the weld metal.

[Second modification]
Next, a second modification of the present invention will be described. In the second modification, as shown in FIG. 13A, notches 70 are formed at both ends of the inner surface 12c of the metal member 2c and the inner surface 12d of the metal member 2d, respectively. The cutout portion 70 is a cutout having a rectangular shape in cross section, and is a portion filled with weld metal. In the present embodiment, the cutout portion 70 has a rectangular shape in cross section, but may have other shapes. By abutting the end portions of the metal members 2c and 2d on the inner surface 12a of the metal member 2a, concave grooves 71 and 71 are formed by the inner surface 12a and the cutout portion 70 of the metal member 2a. Similarly, the recesses 71 and 71 are formed by the inner surface 12b of the metal member 2b and the notch 70 by abutting the end portions of the metal members 2c and 2d on the inner surface 12b of the metal member 2b. That is, the concave grooves 71 are respectively formed at the four inner corners of the inner peripheral surface 12 of the frame member 2 (the metal member to be bonded 10).

  In the frame member inner corner welding step, build-up welding is performed on the four concave grooves 71 formed on the inner peripheral surface 12 of the frame member 2, and the concave metal 71 is filled with the weld metal T. It is preferable to cut the weld metal T protruding from the inner peripheral surface 12 so as to be flush with the inner peripheral surface 12. Since the weld metal T can be filled in the concave groove 71 as in the second modification, the welding operation can be easily performed.

[Third modification]
Next, a third modification of the present invention will be described. In the first embodiment described above, the outer surface joining step by friction stir welding is performed on the unplasticized region appearing on the outer peripheral surface 13 of the metal member to be joined 10 (frame member 2), but welding is performed instead of the outer surface joining step. You may perform the outer surface welding process by.

  In the outer surface welding step shown in the third modified example, as shown in FIGS. 14A and 14B, a concave groove forming step and an outer surface welding step are performed. In the concave groove forming step, a concave groove 80 that continues from the back surface 16 to the front surface 11 is formed along the abutting portions J1 and J2 on the outer peripheral surface 13 of the frame member 2. The concave groove 80 is formed in a rectangular shape in cross section, but may have other shapes. The concave groove 80 is preferably formed so that both ends thereof overlap at least the plasticized region W1b and the plasticized region W1a.

  In the outer surface welding process, build-up welding is performed on the concave groove 80 to fill the weld metal T. The weld metal T protruding from the front surface 11, the back surface 16 and the outer peripheral surface 13 of the frame member 2 is preferably cut so as to be smooth with the respective surfaces. Thus, on the outer peripheral surface 13, instead of friction stir welding, welding may be performed to seal the unplasticized region. Further, the welding operation can be easily performed by filling the groove 80 with the weld metal T while forming the groove 80. In the third modification, welding may be performed directly on each abutting portion without forming the concave groove 80.

  Although the embodiments of the present invention have been described above, modifications can be made as appropriate without departing from the spirit of the present invention. For example, in this embodiment, the metal members 2a to 2d are abutted and the frame member 2 is formed by friction stir welding, but the manufacturing method of the frame member 2 is not limited. For example, the frame member 2 may be formed by casting. Moreover, in this embodiment, although the external shape and opening of the structure 1 were formed so that a planar view rectangle might be exhibited, a circle, an ellipse, and another polygonal shape may be sufficient.

DESCRIPTION OF SYMBOLS 1 Structure 2 Frame member 2a Metal member 2b Metal member 2c Metal member 2d Metal member 3 Lid board 10 Joined metal member 40 Step part 41 Step part bottom face 42 Step part side surface 51 Starting end part 61 Groove 71 71 Groove 80 Groove J1 Butt part J2 Butt part J3 Butt part J4 Butt part J5 Butt part F Temporary joining rotary tool G Main joining rotary tool

Claims (3)

A joining method for joining a pair of metal members exhibiting a rectangular parallelepiped,
A butting step of matching so that the flat end face of the flat side and the other of the metal member of one of said metal member is an inner corner is formed,
Friction agitation is performed on the abutting portion formed in the abutting process from the end surface of one of the metal members and the one side surface of the other metal member that is flush with the end surface using the main rotating tool for welding. An outer surface joining process;
In the outer surface joining step, a punch hole formed when the stirring pin of the main welding rotary tool is removed is provided on one end surface of the metal member or one side surface of the other metal member, and the punch hole is repaired. A punch hole repair process,
An inner corner that performs overlay welding on a side surface of one metal member and an inner corner portion formed by the side surface of the metal member and the other side surface of the other metal member with respect to the abutting portion formed in the abutting step. A welding method comprising: a partial welding step . The hole repair process is
A filling metal member insertion step of filling the punched hole with a filling metal member;
2. A joining method according to claim 1, further comprising a repair joining step of performing friction stir welding by moving a rotating tool along a joint between the metal member and the filling metal member.   The joining method according to claim 2, further comprising a repair welding step of filling a punched hole formed when the stirring pin of the rotary tool is removed in the repair joining step with a weld metal.

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