JP2009101401A - Joining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joining method which can carry out friction stir welding to the butted portion of metallic members from the front face side and the back surface side of the metallic members, and also can improve the tightness and the water tightness of the metallic members. <P>SOLUTION: The present joining method includes: a butting step for forming a joining metallic member 1 by butting end faces of a pair of metallic members on each other; a first final joining step for carrying out the friction stir welding to the joining portion J1 of the joining metallic member 1 from its front face A side; a second final joining step for carrying out the friction stir welding to the joining portion J1 from the back surface B side of the joining metallic member 1; and a welding joining step for carrying out welding to the joining portion J1 from the side surface side of the joining metallic member 1. The joining method is characterized in that a front face side plasticized region W1 formed in the first final joining step and a back surface side plasticized region W2 formed in the second final joining step are overlapped and that, in the welding joining step, these regions W1, W2 are hermetically sealed with weld metal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Friction stir welding (FSW = Friction Stir Welding) is known as a method for joining metal members. Friction stir welding is a process of rotating a rotating tool along the abutting portion between metal members, and plastically flowing the metal at the abutting portion by frictional heat between the rotating tool and the metal member, so that the metal members are solid-phased. It is what is joined. In general, the rotating tool is formed by protruding a stirring pin (probe) on the lower end surface of a cylindrical shoulder portion.

FIG. 12 is a perspective view showing a conventional joining method in which friction stir welding is performed on a pair of metal members. As shown in FIG. 12, when the thickness of the metal members 101 and 101 to be joined is larger than the length of the stirring pin of the rotary tool (not shown), after performing the friction stir welding from the surface 102 side of the metal member 101 In some cases, friction stir welding is also performed from the back surface 103 side.
That is, in the conventional joining method, the friction stir welding is performed from both sides of the front surface 102 and the back surface 103 along the abutting portion 104 (two-dot chain line) of the metal members 101, 101, and the plasticized region 105 formed by the friction stir welding is formed. , 106 are joined so that the central portions in the thickness direction are in contact with each other. Thereby, in the butt | matching part 104, it can join without a clearance gap.

Japanese Patent Laying-Open No. 2005-131666 (see FIG. 7)

  However, in the conventional bonding method, as shown in FIG. 12, in the plasticized regions 105 and 106, a tunnel-like cavity defect continuous from one side surface 107 to the other side surface 108 (hereinafter referred to as a tunnel-like cavity defect 109). May occur. The tunnel-like cavity defect 109 is caused by a shortage of metal in order to fill a fine gap in the abutting portion 104 or a burr generated by friction stirring. The cavity defect 109 is a cause of reducing the water tightness and air tightness of the metal members 101 and 111.

  From such a viewpoint, the present invention provides a joining method capable of performing frictional stirring on the abutting portion between metal members from the front surface side and the back surface side of the metal member and improving the air tightness and water tightness of the metal member. This is the issue.

  The joining method according to the present invention that solves such a problem includes a joining step in which end surfaces of a pair of metal members are butted to form a joined metal member, and the joined parts to the joined part of the joined metal member A first main joining step in which friction agitation is performed from the surface of the metal member; a second main joining step in which friction agitation is performed from the back surface of the metal member to be joined to the abutting portion; and the joint to be joined to the abutting portion. A welding joining step for welding from the side of the metal member, and overlapping the front side plasticizing region formed in the first main joining step and the back side plasticizing region formed in the second main joining step In addition, in the welding joining step, the front surface side plasticized region and the back surface side plasticized region are sealed with a weld metal.

  According to this joining method, since the front side plasticized region and the back side plasticized region are overlapped, it is possible to form a joined metal member having no unplasticized region at the butt portion, and to join the joined metal member. Since the tunnel-like cavity defect exposed on the side surface of the metal is sealed with weld metal by welding, the airtightness and watertightness of the metal member to be joined can be improved.

  Further, the present joining method includes a concave groove forming step of forming a concave groove along the abutting portion of the side surface of the metal member to be joined before the welding joining step, and in the welding joining step, It is preferable to fill the groove with the weld metal.

  According to such a joining method, even if an oxide film is formed on the side surface of the metal member to be joined, it can be removed when the concave groove is formed.

  Moreover, in this joining method, it is preferable that the width | variety of the said ditch | groove is smaller than the width | variety of the said surface side plasticization area | region and the said back surface side plasticization area | region.

  According to such a joining method, it is possible to reduce the labor for forming the concave groove and to reduce the filling amount of the weld metal, thereby reducing the material cost.

  Moreover, in this joining method, it is preferable that the said welding joining process includes the excision process of excising the part which protruded from the side surface of the said to-be-joined metal member among the said weld metals.

  According to this joining method, the finished surface can be formed smoothly by cutting away the weld metal protruding from the side surface. In addition, the part which protruded from the side surface of the to-be-joined metal member among weld metals is also hereafter called a build-up part.

  Moreover, in this joining method, it is preferable to form a pilot hole in advance at a planned insertion position of the rotary tool that performs friction stirring. According to such a joining method, it is possible to reduce press-fit resistance when the rotary tool is pushed in. Thereby, while improving the precision of friction stir welding, a joining operation can be performed rapidly.

  According to the joining method according to the present invention, the abutting portions between the metal members can be frictionally stirred from the front surface side and the back surface side of the metal members, and the air tightness and water tightness of the metal members can be improved.

  As shown in FIG. 1, the joining method according to the present invention is a metal member to be joined with respect to the abutting portion J <b> 1 of the metal member 1 to be joined formed by abutting the end surfaces of the first metal member 1 a and the second metal member 1 b. 1 is characterized in that the friction stir from the front surface A and the back surface B of 1 and the weld metal T is filled in the concave grooves K formed on both side surfaces. First, the metal member 1 to be joined, the tab material used at the time of friction stirring, and the rotary tool will be described in detail.

  As shown in FIG. 2, the bonded metal member 1 is formed by abutting the end surfaces of the first metal member 1a and the second metal member 1b having substantially the same shape. The first metal member 1a and the second metal member 1b are made of a friction-stirring metal material such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy. Although there is no restriction | limiting in particular in the shape and dimension of the 1st metal member 1a and the 2nd metal member 1b, It is desirable to make the thickness dimension in the abutting part J1 the same at least.

  As shown in FIG. 2, the first tab member 2 and the second tab member 3 are arranged so as to sandwich the abutting portion J1 of the metal member 1 to be bonded. It covers the seams (boundary lines) that appear on both sides. Although there is no restriction | limiting in particular in the material of the 1st tab material 2 and the 2nd tab material 3, In this embodiment, it forms with the metal material of the same composition as the to-be-joined metal member 1. FIG. Moreover, there is no restriction | limiting in particular also in the shape and dimension of the 1st tab material 2 and the 2nd tab material 3, In this embodiment, the thickness dimension is the same as the thickness dimension of the to-be-joined metal member 1 in the butt | matching part J1. I have to.

  Next, referring to FIG. 3, a rotary tool F used for temporary joining (hereinafter referred to as “temporary joining rotary tool F”) and a rotary tool G used for main joining (hereinafter referred to as “main joining rotational tool G”). Will be described in detail.

  A temporary tool F for temporary joining shown in FIG. 3A is made of a metal material harder than the metal member 1 to be joined, such as tool steel, and has a cylindrical shoulder portion F1 and a lower end face F11 of the shoulder portion F1. And an agitating pin (probe) F2 provided in a protruding manner. The dimensions and shape of the temporary joining rotary tool F may be set according to the material, thickness, etc. of the metal member 1 to be joined, but at least the main joining rotary tool G (used in the first main joining step described later) (See (b) of FIG. 3). 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 is preferably 3 to 15% of the thickness t of the metal member 1 to be joined at the abutting portion J1 (see FIG. 3B), but at least the rotation for main joining it is desirable to be smaller than the length L ₁ of the stirring pin G2 of the tool G.

  3B is made of a metal material harder than the metal member 1 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 ₁ of the stirring pin G2 is preferably set to be 1/2 or more 3/4 of the thickness t of the bonding metal member 1 in the butting portion J1 (see in FIG. 2 (c)) More preferably, it is desirable to set so as to satisfy the relationship of 1.01 ≦ 2L ₁ /t≦1.10.

  The joining method according to this embodiment will be described in detail below. The bonding method according to the present embodiment includes (1) a butt process, (2) a temporary bonding process, (3) a first main bonding process, (4) a second main bonding process, (5) a groove forming process, (6 ) Includes a welding process. In the description, the top, bottom, front, back, left, and right follow the arrows in FIG.

(1) Butting process The butting process includes a butting process in which both end surfaces of the first metal member 1a and the second metal member 1b are butted to form the metal member 1 to be joined, and tab materials on both side surfaces of the metal member 1 to be joined. And a tab material arranging step to be arranged.

In the abutting step, as shown in FIGS. 2A to 2C, the bonded metal member 1 is formed by abutting both end surfaces 11a and 11b of the first metal member 1a and the second metal member 1b. As shown in FIG. 2 (c), the surface 12a of the first metal member 1a and the surface 12b of the second metal member 1b are flush with each other, and the back surface 13a of the first metal member 1a and the second metal member 1b. Are formed flush with the back surface 13b. Further, as shown in FIG. 3 (b), one side surface 14a of the first metal member 1a and one side surface 14b of the second metal member 1b are flush with each other, and the other side of the first metal member 1a. The side surface 15a and the other side surface 15b of the second metal member 1b are flush with each other. An abutting portion J1 is formed on the butting surfaces of the first metal member 1a and the second metal member 1b.
Here, the surface of the metal member 1 to be bonded is the front surface A, the back surface is the back surface B, one side surface is the first side surface C, and the other side surface is the second side surface D.

  In the tab material arranging step, as shown in FIGS. 2A and 2B, the first tab material 2 and the second tab material 3 are formed along the abutting portions J1 exposed on both side surfaces of the metal member 1 to be joined. Place. The first tab member 2 is disposed so that the contact surface 21 of the first tab member 2 contacts the second side surface D as shown in FIG. The second tab member 3 is arranged so that the contact surface 31 of the second tab member 3 contacts the first side surface C. The front and back surfaces of the first tab material 2 and the second tab material 3 are formed flush with the front surface A and the back surface B of the bonded metal member 1. Moreover, as shown to (a) of FIG. 2, the butt | matching part J2 is formed in the butt | matching surface of the to-be-joined metal member 1 and the 1st tab material 2, and the to-be-joined metal member 1 and the 2nd tab material 3 of FIG. A butting portion J3 is formed on the butting surface.

In the present embodiment, the corners 2a, 2a formed by the first tab member 2 and the metal member 1 to be joined are temporarily joined by welding. Thereby, the opening at the time of carrying out friction stirring of the 1st tab material 2 and the to-be-joined metal member 1 can be prevented. Similarly, the corners 3a and 3a formed by the second tab member 3 and the metal member 1 to be joined are temporarily joined by welding.
When the abutting step is completed, the metal member 1 to which the tab material is temporarily joined is placed on a frame of a friction stirrer (not shown) and restrained so as not to move using a jig such as a clamp.

(2) Temporary joining process The temporary joining process includes a temporary joining process in which friction stirring is performed along the abutting part J2, the abutting part J1 and the abutting part J3, and a pilot hole formation for forming a pilot hole on the surface of the second tab member 3. Process.

In the temporary joining step, as shown in FIG. 4, one temporary joining rotary tool F is moved so as to form a one-stroke writing movement trajectory (bead), and continuously with respect to the abutting portions J2, J1, and J3. And friction stir. That is moved to the end position E _P without disengaging the starting position of the friction stir S _P to the inserted rotating temporary welding tool stirring pin F F2 (shown in FIG. 3 (a) refer) to the middle.
In the present embodiment, the start position S _P output friction stir First tab member 2 is provided, although the end position E _P provided on the second tab member 3, the position of the start position S _P and the end position E _P It is not intended to limit.

Provisional bonding step, first, to position the rotary tool F for temporary bonding directly on the start position S _P provided in place of the first tab member 2, followed lowers while clockwise rotation tool F for temporary joining pressing the stirring pin F2 at the start position _{S P} Te. When the entire stirring pin F2 enters the first tab member 2 and the entire lower end surface F11 of the shoulder portion F1 contacts the surface 22 of the first tab member 2, as shown in FIG. Rotate F and move it relative to the starting point s2.

  When the friction stir is continuously performed up to the starting point s2, the rotating tool F for welding is moved as it is along the abutting portion J2 without detaching the rotating tool F for temporary joining at the starting point s2, and the abutting portion J2 is frictionally stirred. When the rotary tool F for temporary bonding is rotated to the right, there is a possibility that a fine bonding defect may occur on the left side of the moving direction of the temporary bonding rotary tool F. It is desirable to set the positions of the start point s2 and the end point e2 so that the metal member 1 to be bonded is positioned at the position. If it does in this way, since it becomes difficult to generate | occur | produce a joining defect on the to-be-joined metal member 1 side, it becomes possible to obtain a high quality joined body.

  By the way, when the temporary bonding rotary tool F is rotated counterclockwise, there is a possibility that a fine bonding defect may occur on the right side of the moving direction of the temporary bonding rotary tool F. It is desirable to set the position of the start point and the end point so that the metal member 1 to be joined is located on the left side. Specifically, although illustration is omitted, a start point is provided at the position of the end point e2 when the temporary joining rotary tool F is rotated to the right, and the position of the start point s2 when the temporary joining rotary tool F is rotated to the right. An end point may be provided at.

  When the temporary joining rotary tool F reaches the end point e2, the temporary joining rotary tool F is temporarily moved into the first tab member 2 side without being detached and moved to the start point s1. When the temporary joining rotary tool F reaches the starting point s1, the temporary joining rotary tool F is moved along the abutting portion J1, and frictional stirring is continuously performed over the entire length of the abutting portion J1.

When the temporary welding rotary tool F reaches the end point e1, it temporarily enters the second tab member 3 and continues the frictional stirring without removing the temporary welding rotary tool F until the starting point s3. Migrate to Provisional joining rotary tool F is moving the rotary tool F for temporary joining to the end position E _P set in the inside of the second tab member 3 reaches the end point e3, rotary tool F for temporary bonding of the second tab member 3 To leave.
In the present embodiment, it is provided with end position E _P on the extension of the butting portion J1 of the joined metal members 1. Incidentally, the end position E _P is also a friction stirring start position S _M1 in the first main joining process described later. In the present embodiment, the temporary bonding route is set as described above, but the route is not limited to this, and another route may be used.

Under the hole forming step, as shown in FIG. 3 (b), to form a prepared hole P1 at the start position S _M1 of the friction stir in the single bonding step. That is, the pilot hole forming step is a step of forming the pilot hole P1 at a position where the stirring pin G2 of the main rotating tool G is to be inserted. Thereby, the insertion resistance (press-fit resistance) of the stirring pin G2 of the rotating tool G for main joining can be reduced.
Although there is no restriction | limiting in particular in the form of the pilot hole P1, In this embodiment, it is cylindrical. Maximum bore diameter Z ₁ of the prepared hole P1 is smaller than the maximum outer diameter (upper end diameter) Y ₂ of the stirring pin G2 of the joining rotation tool G.

(3) First Main Joining Process In the first main joining process, the abutting portion J1 of the metal member 1 to be joined is frictionally stirred from the surface A using the main joining rotary tool G.
In the first one bonding step, as shown in (a) ~ (c) of FIG. 5, the stirring pin G2 of the joining rotation tool G inserted (press-fitted) into the prepared hole P1 formed in the start position S _M1, The inserted stirring pin G2 is moved to the end position E _M1 without being removed halfway. In this embodiment, the second tab member 3 is provided with the friction stirring start position S _M1 and the first tab member 2 is provided with the end position E _M1 . However, the positions of the start position S _M1 and the end position E _M1 are as follows. It is not intended to limit.

The first main joining process will be described in more detail with reference to FIGS.
First, as shown in FIG. 5A, the main welding rotary tool G is positioned immediately above the pilot hole P1 (start position S _M1 ), and then the main welding rotary tool G is rotated clockwise and lowered. The tip of the stirring pin G2 is inserted into the pilot hole P1. When the stirring pin G2 enters the pilot hole P1, the peripheral surface (side surface) of the stirring pin G2 comes into contact with the hole wall of the pilot hole P1, and the metal fluidizes plastically from the hole wall. In such a state, the agitation pin G2 is press-fitted while pushing the plastic fluidized metal away from the peripheral surface of the agitation pin G2, so that it is possible to reduce the press-fitting resistance in the initial press-fitting stage. Since the stirring pin G2 contacts the hole wall of the pilot hole P1 and the frictional heat is generated before the shoulder portion G1 of the rotating tool G for main bonding contacts the surface 32 of the second tab member 3, plastic fluidization occurs. It is possible to shorten the time until.

  When the entire stirring pin G2 enters the second tab member 3 and the entire lower end surface G11 of the shoulder portion G1 comes into contact with the surface 32 of the second tab member 3, as shown in FIG. While performing agitation, the main rotating tool G is relatively moved toward one end of the abutting portion J1 of the metal member 1 to be joined, and further, the abutting portion J3 is traversed to enter the abutting portion J1. When the rotary tool for welding G is moved, the metal around the stirring pin G2 is plastically fluidized at the same time, and at the position away from the stirring pin G2, the plastic fluidized metal is again hardened and plasticized. A region W1 (hereinafter referred to as “surface-side plasticized region W1”) is formed.

  When there is a possibility that the amount of heat input to the metal member 1 to be bonded becomes excessive, it is desirable to cool by supplying water around the rotating tool G for bonding. In addition, when cooling water enters the gap of the abutting portion J1 of the metal member 1 to be bonded, there is a possibility that an oxide film is generated on the bonding surface. In this embodiment, the temporary metal bonding process is performed to perform the metal member to be bonded. Since the joint of the one abutting portion J1 is closed, it is difficult for the cooling water to enter the gap of the abutting portion J1, and thus there is no possibility of deteriorating the quality of the joint portion.

When the main rotation tool G is relatively moved to the other end of the abutting portion J1, the abutting portion J2 is moved across the abutting portion J2 while performing frictional stirring, and is then relatively moved toward the end position E _M1 . When the main welding rotary tool G reaches the end position E _M1 , as shown in FIG. 5C, the main welding rotary tool G is raised while rotating to disengage the stirring pin G <b> 2 from the end position E _M1 . .

(4) Second Main Joining Step In the second main joining step, the abutting portion J1 of the metal member 1 to be joined is fully frictionally agitated from the back surface B using the main joining rotary tool G.
First, after the first main joining process is completed, the metal member 1 to be joined is once removed from a friction stirrer (not shown), and is rotated halfway along the longitudinal axis shown in FIG. 1 so that the back surface B faces upward. And fix it again. In addition, the pilot hole P2 is formed in the back surface 33 of the 2nd tab material 3 prior to a 2nd main joining process.

In the second main joining step, as shown in FIGS. 6A to 6C, the main joining rotating tool rotated to the right in the pilot hole P <b _{> 2} formed at the start position SM _< b> 2 set in the second tab member 3. The G stirring pin G2 is inserted (press-fitted), and the inserted stirring pin G2 is moved to the end position E _M2 without being removed halfway. In the present embodiment, the friction stir start position S _M2 is provided on the second tab member 3 and the end position E _M2 is provided on the first tab member 2, but the positions of the start position S _M2 and the end position E _M2 are provided. It is not intended to limit.

Since the second main joining process is substantially the same as the first main joining process, the description of the overlapping parts is omitted. In the second main joining step, the back side plasticized region W2 is formed by friction stirring. In the second main joining step, as shown in FIGS. 6B and 6C, friction stir is performed so that the front surface side plasticized region W1 and the back surface side plasticized region W2 overlap. That is, the sum of the depth W1d of the front side plasticizing region W1 and the depth W2d of the back side plasticizing region W2 is formed to be larger than the thickness t of the metal member 1 to be joined. Thereby, since all the clearance gaps of the abutting part J1 can be friction-stirred, the airtightness and watertightness of the to-be-joined metal member 1 can be improved.
In addition, before performing a 2nd main joining process, the above-mentioned temporary joining process may be performed and the joining parts J1, J2, and J3 may be temporarily joined.

  When the second main joining process is completed, as shown in FIG. 7, the first tab material 2 and the second tab material 3 are cut out from the metal member 1 to be joined. A tunnel-like cavity defect R and an oxide film U are formed in the front side plasticization region W1 and the back side plasticization region W2 of the metal member 1 to be joined. The tunnel-like cavity defect R is a cavity defect that communicates from the first side surface C to the second side surface D. In this embodiment, the main-joining rotary tool G is rotated to the right. It is formed on the left side in the direction of travel. That is, the tunnel-like cavity defect R is formed in the second metal member 1b in the surface side plasticized region W1. Moreover, the tunnel-like cavity defect R is formed in the 1st metal member 1a in the back surface side plasticization area | region W2. Both ends of the tunnel-like cavity defect R are exposed to the first side surface C and the second side surface D.

  The oxide film U is plastic because the oxide film existing between the tab material and the metal member 1 to be bonded is wound on the metal member 1 side when the rotary tool G for bonding passes through the abutting portions J2 and J3. Formed on both ends of the conversion region. In the present embodiment, the oxide film U rotates the main welding rotary tool G to the right. Therefore, the first metal member 1a and the second side surface D on the first side surface C in the back surface plasticizing region W2. It is formed in the upper second metal member 1b. Moreover, in the surface side plasticization area | region W1, it forms in the 2nd metal member 1b on the 1st side C, and the 1st metal member 1a on the 2nd side D.

(5) Concave groove forming process In the concavity groove forming process, the concave grooves K and K are formed along the abutting portion J1 on the first side surface C and the second side surface D of the metal member 1 to be joined. The concave groove K is a concave portion that is filled with a weld metal in a welding joining process described later. In this embodiment, the concave groove K is continuously formed from the back surface B to the front surface A with a constant width Ka and depth Kb using a known end mill or the like.

  By providing the concave groove K, it is possible to suitably fill the weld metal and to remove the oxide film U (see FIG. 7) when performing welding joining described later. The width Ka and the depth Kb of the concave groove K may be appropriately set according to the size (range) of the oxide film U. Moreover, it is preferable that the width Ka of the concave groove K and the width Wa of the back surface plasticizing region W2 are formed such that Ka <Wa. Thereby, since the range which fills a weld metal in the case of welding joining can be made small, working efficiency can be improved. In addition, in this embodiment, although the ditch | groove K was formed in the cross sectional view rectangle, it is not limited to this, Other shapes may be sufficient.

(6) Welding and joining process As shown in FIG. 9, the welding and joining process includes a welding and joining process in which welding is performed with respect to the groove K formed on the second side surface D and the first side surface C (see FIG. 8). And a cutting process for cutting off the built-up part (hereinafter also referred to as a built-up part cutting process).
In the welding joining process, overlay welding is performed by TIG welding, MIG welding, or the like, and the groove K is filled with the weld metal T. Thereby, the groove K can be reliably sealed with the weld metal T, and the strength of the joint portion can be increased. Further, even if a tunnel-like cavity defect R continuous from the first side face C to the second side face D is formed, the tunnel-like cavity defect R is divided by filling the groove K with the weld metal T and joined. The metal member 1 can be enclosed. In addition, although the welding material may differ from the to-be-joined metal member 1, in this embodiment, the same material is used.

  In addition, even if it performs a welding joining process, when the oxide film U remains on the surface A and the back surface B of the to-be-joined metal member 1, it welds with respect to the oxide film U, and seals with the weld metal T Also good.

  As shown in FIG. 10, the build-up portion excision step includes a portion protruding from the surface of the first side surface C or the second side surface D (the build-up portion T ′) of the weld metal T filled in the welding joining step. It is a process of excision. The surface of the first side surface C or the second side surface D can be formed smoothly by cutting off the build-up portion T ′.

  According to the joining method according to the present invention described above, the front-side plasticized region W1 and the back-side plasticized region W2 can be overlapped to frictionally stir all gaps of the abutting portion J1, and the metal to be joined. Since the tunnel-like cavity defect R exposed on both side surfaces of the member 1 is sealed with the weld metal T, the airtightness and watertightness of the metal member 1 to be bonded can be improved.

  Moreover, since the oxide film U formed on the bonded metal member 1 during friction stirring is excised in the concave groove forming step, the airtightness and watertightness of the bonded metal member 1 can be further improved. Further, by filling the concave groove K with the weld metal T, the joining strength of the abutting portion J1 can be increased.

Although the best embodiment of the present invention has been described above, modifications can be made as appropriate without departing from the spirit of the present invention.
For example, you may use the rotary tool G for main joining which differs in a 1st main joining process and a 2nd main joining process. For example, as shown in (a) and (b) of FIG. 11, rotating the junction with stirring pin G2 length L ₁ of the joining rotation tool G used in the first present bonding step used in the first two bonding step the sum of the length L ₂ of the 'stirring pin G2 of the' tools G, may be set to more than the thickness of the joining metallic member 1 t in the butting portion J1. Needless to say, the lengths L ₁ and L _{2 of} the stirring pins G2 and G2 ′ are each less than the wall thickness t. In this way, the deep portion of the surface side plasticizing region W1 formed in the first main joining step is frictionally stirred again by the stirring pin G2 ′ of the main welding rotary tool G ′ used in the second main joining step. Therefore, even if the joint defect is continuously formed in the deep part of the surface side plasticized region W1, the joint defect can be divided and made discontinuous. And water tightness can be improved.

  For example, in this embodiment, although the ditch | groove K was formed in the side surface of the to-be-joined metal member 1, you may perform a welding joining process, without forming the ditch | groove K. That is, as shown in FIG. 7, at the stage where the second main joining process is completed, TIG welding is performed on the front side plasticization region W1 and the back side plasticization region W2 exposed on the first side surface C and the second side surface D. After performing etc., you may excise the build-up part. Thereby, since the tunnel-like cavity defect R and the oxide film U can be sealed with the weld metal, water tightness and air tightness can be improved.

  Moreover, although the welding joining process was performed to both surfaces of the to-be-joined metal member 1 in this embodiment, you may perform only to either. Further, the rotation direction and the traveling direction of the temporary bonding rotary tool F and the main bonding rotary tool G are not limited to the above-described forms.

It is the perspective view which showed the joining method which concerns on embodiment of this invention. It is the figure which showed the to-be-joined metal member and tab material which concern on embodiment of this invention, Comprising: (a) is a perspective view, (b) is a top view, (c) is II of (b). It is line sectional drawing. It is the side view which showed the rotation tool which concerns on embodiment of this invention, Comprising: (a) is the rotation tool for temporary joining, (b) shows the rotation tool for main joining. It is the top view which showed the temporary joining process which concerns on embodiment of this invention. It is the II-II sectional view taken on the line of Drawing 4 which showed the 1st main joining process concerning the embodiment of the present invention, (a) is a starting position, (b) is an intermediate position, (c) is an end. Indicates the position. It is sectional drawing which showed the 2nd main joining process which concerns on embodiment of this invention, Comprising: (a) is a start position, (b) is an intermediate position, (c) shows end position vicinity. It is the perspective view which showed the end after the 2nd main joining process which concerns on embodiment of this invention. It is the perspective view which showed the ditch | groove formation process which concerns on embodiment of this invention. It is the front view which showed the welding joining process which concerns on embodiment of this invention. It is the III-III sectional view taken on the line of FIG. 9 which concerns on embodiment of this invention. It is the side view which showed the modification of the rotation tool. It is the perspective view which showed the conventional joining method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal member to be joined 1a 1st metal member 1b 2nd metal member 2 1st tab material 3 2nd tab material A surface B back surface C 1st side surface D 2nd side surface F rotary tool for temporary joining G rotational tool for this joining J1 the end position of the butting portion K groove P1 prepared hole T weld metal W1 surface plasticized region W2 backside plasticized region S _M main bonding step of the starting position E _M main bonding step

Claims (5)

A butting step of butting the end faces of a pair of metal members to form a metal member to be joined;
A first main joining step in which friction agitation is performed from the surface of the metal member to be bonded to the butted portion of the metal member to be bonded;
A second main joining step in which friction agitation is performed from the back surface of the metal member to be joined to the abutting portion;
A welding joint step of performing welding from the side surface of the joined metal member to the abutting portion,
While overlapping the surface side plasticized region formed in the first main joining step and the back side plasticized region formed in the second main joining step,
In the welding and joining step, the front side plasticization region and the back side plasticization region are sealed with a weld metal. Before the welding joining step, including a groove forming step of forming a groove along the abutting portion of the side surface of the metal member to be joined,
The joining method according to claim 1, wherein the weld metal is filled in the concave groove during the welding joining process.   The joining method according to claim 2, wherein a width of the concave groove is smaller than a width of the front surface side plasticized region and the rear surface side plasticized region.   4. The joining method according to claim 1, wherein the welding joining step includes a cutting step of cutting a portion of the weld metal that protrudes from a side surface of the metal member to be joined. 5. The joining method according to any one of claims 1 to 4, wherein a pilot hole is formed in advance at a position where a rotary tool for frictional stirring is to be inserted.

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