JP6273821B2 - Joining method - Google Patents

Description

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

  Friction stir welding (FSW = Friction Stir Welding) is known as a method for joining a pair of metal members. In friction stir welding, metal members are solid-phase bonded by moving the rotating tool along the abutting part between metal members and plastically flowing the metal at the abutting part by frictional heat between the rotating tool and the metal member. It is. In general, the rotating tool is formed by projecting a stirring pin (probe) on the lower end surface of a cylindrical shoulder.

  For example, Patent Document 1 describes an invention in which a base member and a lid plate are joined by friction stirring to form a heat transfer plate. As shown in FIG. 11A, the base member 101 has a lid groove 102 and a concave groove 103 formed on the bottom surface of the lid groove 102. The lid plate 110 is disposed in the lid groove 102 so as to cover the concave groove 103. In the invention according to Patent Literature 1, friction stir welding is performed by moving the rotary tool G along the abutting portion between the concave groove 103 and the lid plate 110. The rotary tool G includes a shoulder G1 and a stirring pin G2 formed on the lower end surface of the shoulder G1. A plasticized region W is formed in the movement locus of the rotary tool G.

  When friction stir welding is performed as described above, the surface 101A of the base member 101 is warped so as to be concave due to thermal contraction. Therefore, in the invention according to Patent Document 1, as shown in FIG. 11B, a technique of performing frictional stirring with the rotary tool G on the back surface 101 </ b> B of the base member 101 is disclosed. When such a process is performed, heat shrinkage also occurs on the back surface 101B, so that the flatness of the heat transfer plate can be improved.

JP 2009-195940 A

  However, as shown in FIG. 11B, since the base member 101 is warped so as to be convex on the back surface 101B, when the rotary tool G is moved in the E1 direction, the lower end surface of the shoulder G1 Of these, the front side in the traveling direction is in contact with the back surface 101B. Further, when the rotary tool is moved in the E2 direction, the rear side in the traveling direction of the lower end surface of the shoulder G1 comes into contact with the back surface 101B. Thereby, there exists a problem that the operativity of the rotation tool G falls.

  Then, this invention makes it a subject to provide the joining method which can improve the operativity of a rotary tool while being able to join metal members flatly.

In order to solve the above-mentioned problem, the present invention is configured to perform friction stir from the surface side of the metal member by relatively moving the first rotary tool including the stirring pin and the shoulder with respect to the abutting portion between the metal members. A first main joining step, and a second main joining step in which friction stir is performed from the back side of the metal member by relatively moving a second rotary tool having a stirring pin with respect to the abutting portion. In the method, a spiral groove is engraved on the outer peripheral surface of the stirring pin of the second rotary tool, and when the second rotary tool is rotated clockwise, the spiral groove is moved from the proximal end to the distal end. When the second rotating tool is rotated counterclockwise, the spiral groove is formed clockwise as it goes from the proximal end to the distal end . the stirring pin of said first rotary tool Insert the serial butting portion, the stirring pin and the shoulder perform friction stir being in contact with the metal member, the amount of deformation of the metallic member is measured after the first one bonding step, the second In the main joining step, the stirring pin of the rotated second rotating tool is inserted into the abutting portion, and friction stirring is performed in a state where only the stirring pin is in contact with the metal member, and the insertion depth of the stirring pin is set. Friction stirring is performed while adjusting the thickness according to the amount of deformation .

According to this manufacturing method, the metal members are deformed in a concave shape on the surface side by the first main joining step, but the metal members joined by heat shrinkage by the second main joining step can be flattened. . Further, in the second main joining step, only the stirring pin of the second rotary tool comes into contact with the metal member, so even if the back surface of the metal member is warped convexly, the second rotary tool The operability can be improved. Moreover, the depth position of the stirring pin with respect to the metal members can be kept constant. Furthermore, by setting the spiral groove in this manner, the plastic fluidized metal during the frictional stirring is guided to the tip side of the stirring pin by the spiral groove. Thereby, the quantity of the metal which overflows to the exterior of the to-be-joined metal member 1 can be decreased.

  Further, in the second main joining step, friction between the metal member to be joined and the second rotary tool can be reduced as compared with the conventional joining method, and the load applied to the friction stirrer can be reduced. Thereby, friction stir welding can be easily performed up to a deep position of the abutting portion.

  Moreover, it is preferable that the heat input amount by friction stirring in said 2nd main joining process is smaller than the heat input amount by friction stirring in said 1st main joining process. According to this joining method, since the heat input to the metal members can be balanced, the metal members can be made flatter.

  Further, in the second main joining step, it is preferable that the friction stir is performed while the stirring pin of the second rotary tool is inserted into the plasticized region formed in the first main joining step.

  According to such a joining method, the water tightness and air tightness between metal members can be improved.

  Moreover, it is preferable to include the temporary joining process which performs temporary joining of the said metal members before performing the said main joining process. According to this joining method, it is possible to prevent the opening of the abutting portion during the main joining step.

  Moreover, it is preferable to perform the said main joining process by inserting the said stirring pin in the said prepared hole after providing a prepared hole in the tab material arrange | positioned beside the said abutting part. According to this joining method, it is possible to clean the joining surface between the metal members by using the tab material. Further, by forming the prepared hole, the first rotating tool and the second rotating tool can be easily inserted.

  According to the joining method concerning the present invention, metal members can be joined together flatly, and the operativity of a rotation tool can be improved.

It is a figure for demonstrating arrangement | positioning of the metal member which concerns on 1st embodiment, a 1st tab material, and a 2nd tab material, Comprising: (a) is a perspective view, (b) is a top view, (c) is ( b) is a cross-sectional view taken along the line II, and FIG. 4D is a cross-sectional view taken along the line II-II of FIG. (A) is a side view for demonstrating the rotation tool for temporary joining, (b) is a side view for demonstrating the 1st rotation tool for main joining. It is a side view for demonstrating the 2nd rotation tool for main joining. It is the perspective view which showed the fixation state of the metal member which concerns on 1st embodiment. It is the top view which showed the 1st temporary joining process which concerns on 1st embodiment. It is sectional drawing which showed the 1st temporary joining process which concerns on 1st embodiment. It is the figure which showed the 1st main joining process which concerns on 1st embodiment, (a) is a start position, (b) is an intermediate position, (c) shows an end position. It is the perspective view which showed the 1st main joining process which concerns on 1st embodiment. It is the figure which showed the 2nd main joining process which concerns on 1st embodiment, Comprising: (a) is a start position, (b) is an intermediate position, (c) shows an end position. It is sectional drawing which showed the state which finished 1st embodiment. (A), (b) is sectional drawing which shows the conventional friction stir welding.

[First embodiment]
Embodiments of the present invention will be described with reference to the drawings. In this embodiment, as shown in FIG. 1, the case where the metal members 1a and 1b are joined together in a straight line is illustrated. First, the metal members 1a and 1b to be joined will be described in detail, and the first tab member 2 and the second tab member 3 used when joining the metal members 1a and 1b will be described in detail.

  The metal members 1a and 1b are plate-like members having a rectangular shape in cross section, and are made of a friction-stirring metal material such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy. In the present embodiment, one metal member 1a and the other metal member 1b are formed of a metal material having the same composition. Although there is no restriction | limiting in particular in the shape and dimension of metal member 1a, 1b, It is desirable to make the thickness dimension in the butt | matching part J1 the same at least. In addition, the metal member which faced | matched the metal member 1a and the metal member 1b is called the to-be-joined metal member 1, the surface of the to-be-joined metal member 1 is the surface A, the back is the back B, one side is the 1st side C, and the other The side surface is also referred to as the second side surface D.

  The 1st tab material 2 and the 2nd tab material 3 are arrange | positioned so that the butt | matching part J1 of the to-be-joined metal member 1 may be pinched | interposed, respectively, are attached to the to-be-joined metal member 1, and to-be-joined metal member Cover the seam (boundary line) that appears on one side. 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. 2, a rotary tool used in the temporary joining process (hereinafter referred to as “temporary joining rotary tool H”) and two rotary tools used in the main joining process (hereinafter referred to as “first main joining”). Rotating Tool G ”and“ Second Main Joining Rotating Tool F ”) will be described in detail.

  A temporary tool for temporary joining H shown in FIG. 2A is made of a metal material harder than the metal member 1 to be joined, such as tool steel, and projects into a shoulder H1 having a cylindrical shape and a lower end face H11 of the shoulder H1. It comprises a stirring pin (probe) H2 provided. The dimensions and shape of the temporary bonding rotary tool H may be set according to the material and thickness of the metal member 1 to be bonded, but at least for the first main bonding used in the first main bonding process described later. It is made smaller than the rotating tool G (see FIG. 2B). This makes it possible to perform temporary bonding with a load smaller than that of the main bonding, thereby reducing the load applied to the friction stirrer during temporary bonding. Since the moving speed (feeding speed) can be made higher than the moving speed of the first main joining rotary tool G, the working time and cost required for temporary joining can be reduced.

The lower end surface H11 of the shoulder H1 is a part that plays a role of preventing the scattering to the surroundings by pressing the plastic fluidized metal, and is formed in a concave shape in the present embodiment. There is no particular limitation on the size of the outer diameter X ₁ of the shoulder H1, in this embodiment, is smaller than the outer diameter Y ₁ of the shoulder G1 of the first aspect of the present joining rotation tool G.

  The stirring pin H2 hangs down from the center of the lower end surface H11 of the shoulder H1, and in the present embodiment, is formed in a tapered truncated cone shape. In addition, a stirring blade engraved in a spiral shape is formed on the peripheral surface of the stirring pin H2.

  The first main rotating tool G shown in FIG. 2B is made of a metal material harder than the metal member 1 to be joined, such as tool steel, and has a cylindrical shoulder G1 and a lower end surface of the shoulder G1. A stirring pin (probe) G2 protruding from G11 is provided. The first main joining rotary tool G corresponds to the “first rotary tool” in the claims.

  The lower end surface G11 of the shoulder G1 is formed in a concave shape like the temporary joining rotary tool H. The stirring pin G2 hangs down from the center of the lower end surface G11 of the shoulder G1, and in the present embodiment, is formed in a tapered truncated cone shape. In addition, a stirring blade engraved in a spiral shape is formed on the peripheral surface of the stirring pin G2.

  As shown to (a) of FIG. 3, the 2nd main rotation tool F for main joining is comprised by the connection part F1 and the stirring pin F2. The second main joining rotary tool F corresponds to a “second rotary tool” in the claims. The second main joining rotary tool F is made of, for example, tool steel. The connection part F1 is a part connected to the rotating shaft T of the friction stirrer shown in FIG. The connecting portion F1 has a cylindrical shape, and is formed with screw holes BH and BH to which bolts are fastened.

  The stirring pin F2 hangs down from the connecting portion F1 and is coaxial with the connecting portion F1. The stirring pin F2 is tapered as it is separated from the connecting portion F1. A spiral groove F3 is formed on the outer peripheral surface of the stirring pin F2. In the present embodiment, the spiral groove F3 is formed in a counterclockwise direction from the base end toward the tip end in order to rotate the second main joining rotary tool F to the right.

  In addition, when rotating the 2nd main joining rotation tool F counterclockwise, it is preferable to form the spiral groove F3 clockwise as it goes to a front-end | tip from a base end. By setting the spiral groove F3 in this way, the plastic fluidized metal at the time of frictional stirring is guided to the tip side of the stirring pin F2 by the spiral groove F3. Thereby, the quantity of the metal which overflows the exterior of the to-be-joined metal member 1 can be decreased.

  As shown in FIG. 3B, when performing friction stir welding using the second main rotating tool F for main welding, only the rotated stirring pin F2 is inserted into the metal member 1 to be welded, The metal member 1 and the connecting portion F1 are moved while being separated from each other. In other words, the friction stir welding is performed with the base end portion of the stirring pin F2 exposed. A plasticized region W3 (back surface plasticized region W3) is formed in the movement trajectory of the second main welding rotary tool F by hardening of the friction-stirred metal.

  Hereinafter, the joining method according to the present embodiment will be described in detail. The bonding method according to this embodiment includes (1) a first preparation step, (2) a first preliminary step, (3) a first main bonding step, (4) a second preparation step, and (5) a first. Including a second preliminary step and (6) a second main joining step. The first preliminary step and the first main joining step are steps executed from the surface A side of the metal member 1 to be joined, and the second preliminary step and the second main joining step are the metal to be joined. This is a process executed from the back surface B side of the member 1.

(1) First Preparation Step The first preparation step will be described with reference to FIG. The first preparation step is a step of preparing a contact member (first tab member 2 and second tab member 3) provided with a friction stirring start position and an end position of the metal members 1 to be bonded. In the embodiment, a degreasing process for removing dirt such as oil and fat from the metal members 1a and 1b, the first tab material 2 and the second tab material 3, a butting process for butting the metal members 1a and 1b, and the bonded metal member 1 The tab material arranging step of arranging the first tab material 2 and the second tab material 3 on both sides of the abutting portion J1, and the first tab material 2 and the second tab material 3 are temporarily joined to the metal member 1 to be joined by welding. A welding process and a fixing process for fixing the bonded metal member 1 to the table are provided.

  In the degreasing process, the metal members 1a, 1b, the first tab material 2 and the second tab material 3 which have been subjected to the chamfering process are immersed in a degreasing treatment liquid, and oils and fats such as processing oil adhering to the surface where each member is abutted. Remove minutes and dirt. Specifically, the end surfaces 11 and 11 where the metal member 1a and the metal member 1b are abutted, and the metal members 1a and 1b where the metal member 1 to be joined, the first tab material 2 and the second tab material 3 are abutted. The degreasing process is performed on the side surface 14, the contact surface 21 of the first tab member 2, and the contact surface 31 of the second tab member 3. In the degreasing step, at least the surface with which each member is abutted may be processed, but the surface adjacent to the abutting surface may be degreased.

  In the abutting process, as shown in FIG. 1C, the end surface 11 of the other metal member 1b is brought into close contact with the end surface 11 of the one metal member 1a, and the surface 12 of the one metal member 1a and the other metal member The front surface 12 of 1b is flush, and the back surface 13 of one metal member 1a and the back surface 13 of the other metal member 1b are flush. Further, the side surfaces 14 and 14 of one metal member 1a and the side surfaces 14 and 14 of the other metal member 1b are flush with each other.

  In the tab material arranging step, as shown in FIG. 1 (b), the first tab material 2 is arranged on one end side of the abutting portion J1 of the metal member 1 to be bonded, and the contact surface 21 is made to be the metal member 1 to be bonded. The second tab material 3 is disposed on the other end side of the abutting portion J1, and the contact surface 31 is brought into contact with the first side surface C of the metal member 1 to be joined. At this time, as shown in FIG. 1 (d), the surface 22 of the first tab member 2 and the surface 32 of the second tab member 3 are flush with the surface A of the metal member 1 to be joined, and the first tab. The back surface 23 of the material 2 and the back surface 33 of the second tab material 3 are flush with the back surface B of the bonded metal member 1.

  In the welding process, as shown in FIGS. 1A and 1B, the corners 2a and 2a (that is, the metal members 1a and 1b) formed by the metal member 1 and the first tab member 2 are joined. The corner portion formed by the side surface 14 and the side surface 24 of the first tab member 2 is welded to join the metal member 1 to be joined and the first tab member 2, and the metal member 1 to be joined and the second tab member 3. The corners 3a, 3a (that is, the corners formed by the side surface 14 of the metal members 1a, 1b and the side surface 34 of the second tab member 3) formed by welding are joined to the joined metal member 1 and the first The two tab material 3 is joined. In addition, you may perform welding continuously over the full length of each entrance corner part, and you may intermittently perform welding.

  In the fixing step, as shown in FIG. 4, the metal member 1 to be bonded is placed on a table (base) 10 of a friction stirrer and is restrained so as not to move by using a fixing jig 15 such as a clamp. The form of the fixing jig 15 is not particularly limited, but a metal fitting 15a that contacts the surface A of the metal member 1 to be joined, a bolt 15b that is inserted through the metal fitting 15a, and a screw hole 15c into which the bolt 15b is screwed. It consists of. In the present embodiment, the four fixing jigs 15 are used, but the number is not limited.

(2) First preliminary step The first preliminary step is a step performed prior to the first main joining step, and in this embodiment, the abutting portion between the metal member 1 to be joined and the first tab member 2. The first tab material joining step for joining J2, the first temporary joining step for temporarily joining the abutting portion J1 of the metal member 1 to be joined, and the abutting portion J3 of the metal member 1 to be joined and the second tab material 3 A second tab member joining step for joining, and a prepared hole forming step for forming a prepared hole at the friction stirring start position in the first main joining step.

In the first preliminary process, as shown in FIG. 5, one temporary joining rotary tool H is moved so as to form a one-stroke writing movement trajectory (bead), and with respect to the abutting portions J2, J1, and J3. Friction stirring is performed continuously. That is, the stirring pin start position S _P to the inserted rotating temporary welding tool H for friction stir H2 is moved to the end position E _P without disengaging (in see FIG. 2 (a)) to the middle, first tab member A joining process, a 1st temporary joining process, and a 2nd tab material joining process are performed continuously. 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.

Upon reaching the temporary joining rotation tool H is the end position E _P, it is raised while rotating the rotating tool H for temporary joining disengaging the stirring pin H2 from the end position E _P with. As shown in FIG. 6, when the temporary bonding rotary tool H rotated at high speed is inserted into the metal member 1 to be bonded, frictional heat is transmitted into the metal member 1 to be bonded (heat input). Since the metal member 1 to be bonded is in surface contact with the table 10, a part of the frictional heat is released (removed heat) from the entire back surface B of the metal member 1 to be bonded to the table 10 as indicated by an arrow N. The

Then, a pilot hole formation process is performed. Prepared hole forming step, as shown in FIG. 2 (b), a step of forming a prepared hole P1 at the start position S _M1 of the friction stir in the first of the welding process. That is, the pilot hole forming step is a step of forming the pilot hole P1 at the planned insertion position of the agitation pin G2 of the first main welding rotary tool G.

The pilot hole P1 is provided for the purpose of reducing the insertion resistance (press-fit resistance) of the agitation pin G2 of the first main joining rotary tool G. In this embodiment, the agitation pin of the temporary welding rotary tool H is provided. It is formed by expanding the diameter of the punched hole h1 formed when the H2 (see FIG. 2A) is removed with a drill or the like (not shown). If the punch hole h1 is used, the process of forming the pilot hole P1 can be simplified, and the working time can be shortened. Although there is no restriction | limiting in particular in the form of the pilot hole P1, In this embodiment, it is cylindrical. The width Z ₁ and depth Z ₂ of the prepared hole P1 is stirring pin G2 of the size may be appropriately set according to the shape.

  In addition, in this embodiment, although the pilot hole P1 is formed in the 2nd tab material 3, there is no restriction | limiting in particular in the position of the pilot hole P1, You may form in the 1st tab material 2, and the butt | matching part J2 , J3 may be preferably formed on the extended line of the joint (boundary line) of the metal member 1 to be bonded that appears on the surface A side of the metal member 1 to be bonded as in the present embodiment. .

(3) 1st main joining process A 1st main joining process is a process of joining the butting part J1 of the to-be-joined metal member 1 from the surface A side in earnest. In the first main joining step according to the present embodiment, the first main joining rotating tool G shown in FIG. 2B is used, and the metal member to be joined to the abutting portion J1 in a temporarily joined state. Friction stirring is performed from the surface A side of 1.

In the first main joining step, as shown in FIGS. 7A to 7C, the stirring pin G2 of the first main joining rotary tool G is inserted into the pilot hole P1 formed at the start position _SM1 ( The inserted stirring pin G2 is moved to the end position E _M1 without being removed in the middle. That is, in the first main joining process, the friction stirring is started from the pilot hole P1, and the friction stirring is continuously performed up to the end position E _M1 . In this embodiment, the friction stir start position S _M1 is provided on the second tab member 3 and the end position E _M1 is provided on the first tab member 2, but the positions of the start position S _M1 and the end position E _M1 are provided. 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. 7A, the first main joining rotary tool G is positioned immediately above the pilot hole P1 (start position S _M1 ), and then the first main joining rotary tool G is provided. Is rotated downward and 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 the plastic fluidized metal is pushed away by the peripheral surface of the agitation pin G2, so that the press-fitting resistance in the initial press-fitting stage can be reduced.

  When the entire stirring pin G2 enters the second tab member 3 and the entire lower end surface G11 of the shoulder G1 contacts the surface of the second tab member 3, friction stirring is performed as shown in FIG. While being performed, the first 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 first main rotating tool G is moved, the metal around the stirring pin G2 is plastically fluidized in sequence, and the plastic fluidized metal is hardened again at a position away from the stirring pin G2. Thus, a plasticized 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 the surface of the first main rotating tool G by supplying water from the surface A side. In addition, when cooling water enters between the abutting portions J1 of the metal member 1 to be bonded, there is a possibility that an oxide film is generated on the bonding surface. However, in the present embodiment, the first temporary bonding step is performed to be bonded. Since the joint between the metal members 1 is closed, it is difficult for cooling water to enter the abutting portion J1 of the metal member 1 to be joined, and therefore there is no possibility of deteriorating the quality of the joint portion.

At the abutting portion J1 of the metal member 1 to be bonded, a friction stir route is set on the joint of the metal member 1 (on the movement trajectory in the first temporary bonding process), and the first main bonding is performed along the route. By rotating the rotary tool G for relative movement, friction stirring is continuously performed from one end to the other end of the abutting portion J1. When the first main-joining rotary tool G is relatively moved to the other end of the abutting portion J1, the abutting portion J2 is traversed while performing frictional stirring, and is relatively moved toward the end position E _M1 as it is.

In the present embodiment, since the friction stirring end position E _M1 is set on the extension line of the seam (boundary line) appearing on the surface A side of the metal member 1 to be joined, the friction stirring in the first main joining step is performed. The route of can be straight. If the friction stir route is made straight, the moving distance of the first main welding rotary tool G can be minimized, so that the first main welding process can be performed efficiently. It becomes possible to reduce the amount of wear of one main rotating tool G for joining.

When the first main joining rotary tool G reaches the end position _EM1 , as shown in FIG. 7C, the first main joining rotary tool G is raised while rotating to finish the stirring pin G2. It is made to detach | leave from position E _M1 (refer FIG.7 (b)). If the stirring pin G2 is separated upward at the end position E _M1 , a punch hole Q1 having the same shape as the stirring pin G2 is inevitably formed. However, in this embodiment, it is left as it is.

  As shown in FIGS. 7 (b) and 7 (c), when the first main rotation tool G rotated at high speed is inserted into the metal member 1 to be bonded, frictional heat is transmitted into the metal member 1 to be bonded. (Heat input). Since the metal member 1 to be bonded is in surface contact with the table 10, a part of the frictional heat is released (removed heat) from the back surface B of the metal member 1 to be bonded to the table 10 as indicated by an arrow N.

  In this embodiment, as shown in FIGS. 7B and 7C, the first main joining rotation tool G is rotated to the right and the first main joining process is performed. That is, a tunnel-like junction defect may be formed in the metal member 1b. When the friction stir is performed, the left side in the traveling direction is the shear side (the relative speed of the outer periphery of the rotating tool with respect to the bonded portion is a value obtained by adding the moving speed to the size of the tangential speed on the outer periphery of the rotating tool. Therefore, it is considered that the metal is vigorously stirred and softened at a high temperature to be easily discharged as burrs. For this reason, since the metal is insufficient on the left side in the traveling direction, a bonding defect may be formed. Further, the right side of the traveling direction, that is, the metal member 1a side is the flow side (the relative speed of the outer periphery of the rotating tool with respect to the bonded portion is obtained by subtracting the magnitude of the moving speed from the magnitude of the tangential speed on the outer periphery of the rotating tool. Therefore, it is considered that the stirring of the metal is relatively weak and is not easily discharged as burrs, and a relatively dense plasticized region is formed.

  By the way, when the first main rotating tool G is rotated counterclockwise, the right side in the traveling direction becomes the shear side, so that a bonding defect may be formed on the right side in the traveling direction. On the other hand, since the left side in the traveling direction is the flow side, a relatively dense plasticized region is formed. When such a joining defect such as a joining defect is formed in the metal member 1 to be joined, it causes a decrease in the airtightness and water tightness of the metal member 1 to be joined.

  When the first main joining process is completed, burrs generated by friction stirring in the first preliminary process and the first main joining process are removed. Further, the metal member 1 to be joined is released from the fixing jig 15.

  FIG. 8 is a perspective view showing the first main bonding step after the first embodiment. As shown in FIG. 8, when the first preliminary process and the first main bonding process described above are performed, the metal member 1 to be bonded is cooled to cause thermal shrinkage. Deforms into a concave shape.

(4) Second Preparatory Step The second preparatory step is a step performed prior to the second preliminary step. In the present embodiment, the metal member to be bonded is obtained by reversing the front and back of the metal member 1 to be bonded. 1 is fixed to the table 10 with a fixing jig 15 (see FIG. 4). As shown in FIG. 9, the bonded metal member 1 is warped (distorted) due to thermal contraction, so the edges U and U of the bonded metal member 1 and the table 10 come into contact with each other, and the table 10 and the bonded metal member 1 are in contact with each other. A gap P is formed between the surface A of the bonded metal member 1. A tensile stress acts on the back surface B of the metal member 1 to be bonded.

(5) Second Preliminary Step The second preliminary step is a step that is performed prior to the second main joining step, and in this embodiment, the abutting portion J2 between the metal member 1 to be joined and the first tab member 2. A first tab material joining step for joining the joint, a second temporary joining step for temporarily joining the abutting portion J1 of the joined metal member 1, and a joining portion J3 of the joined metal member 1 and the second tab material 3 are joined. A second tab material joining step, and a prepared hole forming step of forming a prepared hole at the friction stirring start position in the second main joining step. Since the second preliminary process is substantially the same as the first preliminary process except for the front and back of the metal member 1 to be joined, detailed description thereof is omitted. By the second temporary joining step, a back side plasticized region W2 is formed on the back side B of the metal member 1 to be joined (see FIG. 9).

(6) Second Main Joining Step The second main joining step is a step of fully joining the abutting portion J1 of the metal member 1 to be joined from the back surface B side. In the second main joining step according to the present embodiment, as shown in FIGS. 9A to 9C, the second main joining rotating tool F is used to join the abutting portion J1. Friction stirring is performed from the back surface B side of the metal member 1.

In the second main joining step, the stirring pin F2 of the second main joining rotating tool F is inserted (press-fitted) into the pilot hole P2 (starting position S _M2 ) provided in the second tab member 3, and the inserted stirring is performed. The pin H2 is moved to the end position E _M2 provided on the first tab member 2 without being removed in the middle. That is, in the second main joining step, friction agitation is started from the pilot hole P2, and friction agitation is continuously performed up to the end position _EM2 .

The second main joining process will be described in more detail with reference to FIGS.
First, as shown in FIG. 9 (a), the second main welding rotary tool F is positioned immediately above the pilot hole P2, and then the second main welding rotary tool F is lowered while rotating clockwise. The tip of the stirring pin F2 is inserted into the pilot hole P2.

  As shown in FIG. 9B, the insertion depth of the second final joining rotary tool F may be set as appropriate, but the tip of the stirring pin F2 is made plastic on the surface side as in this embodiment. It is set to such an extent that it comes into contact with or enters the region W1, and is relatively moved toward one end of the abutting portion J1 of the metal member 1 to be joined. In the second main joining step, even if the tip of the stirring pin F2 reaches the surface side plasticizing region W1, the connecting portion F1 does not come into contact with the metal member 1 to be joined. That is, in the second main joining step, the surface A of the joined metal member 1 is not pressed by the lower surface of the connecting portion F1. A back surface plasticizing region W3 is formed on the movement locus of the second main rotating tool for welding F.

  If the tip of the agitation pin F2 is inserted into the surface side plasticization region W1, the tip side of the surface side plasticization region W1 can be frictionally stirred again, so that a bonding defect is formed on the tip side of the surface side plasticization region W1. If so, the defect can be repaired. In addition, since the entire depth direction of the abutting portion J1 is frictionally stirred by bringing at least the front surface side plasticized region W1 and the back surface side plasticized region W3 into contact with each other, the watertightness and airtightness of the metal member 1 to be bonded are improved. Can be improved.

  Further, in the main joining step, the deformation amount in the height direction of the metal member 1 to be joined fixed to the table 10 is measured before the main joining step, and is adjusted to the deformation amount in the second main joining step. It is preferable to carry out friction stirring while adjusting the insertion depth of the stirring pin F2. That is, it moves so that the movement locus | trajectory of the 2nd main welding rotation tool F may turn along a curved surface of the surface A of the to-be-joined metal member 1. FIG. By doing in this way, the depth and width | variety of the back surface side plasticization area | region W3 can be made constant.

  In addition, what is necessary is just to use a well-known height detection apparatus about the measurement of the deformation amount of the to-be-joined metal member 1. FIG. Further, for example, the main joining process is performed while detecting the deformation amount of the metal member 1 to be bonded using a friction stirrer equipped with a detection device that detects the height from the table 10 to the surface A of the metal member 1 to be bonded. May be performed.

As shown in FIG. 9C, when the second final joining rotary tool F reaches the end position _EM2 , the second final joining rotary tool F is raised while rotating to finish the stirring pin F2. _Detach from the position E _M2 (see FIG. 9C).

  As shown in FIGS. 9B and 9C, when the second main rotation tool F rotated at high speed is inserted into the metal member 1 to be bonded, frictional heat is transferred into the metal member 1 to be bonded. (Heat input). Further, a part of the frictional heat is released (heat is removed) from the edges U and U of the bonded metal member 1 to the table 10 as indicated by an arrow N.

  Since the gap P is formed in the second main joining process, the amount of heat removal is less than that in the first main joining process. Further, in the second main joining step, the friction stir is performed only by the stirring pin F2, so that the amount of heat input is less than that in the first main joining step.

  When the second main joining process is completed, the tab material is cut off. In addition, it is preferable to remove the burr | flash formed in the to-be-joined metal member 1 after finishing each process.

  According to the first embodiment described above, as shown in FIG. 10, if the metal member 1 to be bonded is released from the fixing jig 15 (see FIG. 4) after the second main bonding and left to stand, The joining metal member 1 becomes flat. That is, before the second main joining step, the back surface B side of the metal member 1 to be joined is warped by the heat shrinkage after the first main joining step, but after the second main joining step, Warpage is corrected by heat shrinkage, and the bonded metal member 1 can be flattened. In the second main joining step, only the stirring pin F2 of the second main joining rotating tool F comes into contact with the metal member 1 to be joined. Thereby, even if the back surface B of the to-be-bonded metal member 1 is warped in a convex shape, the operability of the second main joining rotary tool F can be improved in the second main joining step.

  As described above, since the gap P is generated, the amount of heat removal is small in the second main joining step. Further, in the second main joining step, the friction stir is performed only by the stirring pin F2, and therefore, it is easy to set the heat input amount in the second main joining step smaller than the heat input amount in the first main joining step. It is. From the above, the balance between (heat input-heat extraction) of the metal member 1 to be bonded in the first main joining process and (heat input-heat extraction) of the metal member 1 to be bonded in the second main bonding process. As a result, the bonded metal member 1 can be flattened.

  Further, in the second main joining step, the front side plasticizing region W1 is formed by inserting the tip of the second main joining rotating tool F into the surface side plasticizing region W1 formed in the first main joining step. Can be friction-stirred again. Thereby, the joining defect which may generate | occur | produce in a plasticization area | region can be repaired, and watertightness and airtightness can be improved.

  Further, in the second main joining step, it is possible to reduce the friction between the metal member 1 to be joined and the second main joining rotary tool F to be joined as compared with the conventional joining method, and a burden on the friction stirrer. Can be reduced. Moreover, since the load concerning a friction stirrer can be reduced, it can join to the deep position of the abutting part J1 in the state which does not apply a big load to a friction stirrer.

  Moreover, in this embodiment, since the temporary joining process is performed prior to the main joining process, the friction stir welding can be performed without separating the metal members 1a and 1b from each other.

  In the first embodiment, the amount of heat input on the front surface side and the back surface side of the metal member 1 to be bonded is adjusted by changing the type of the rotating tool, but the present invention is not limited to this. For example, by increasing the moving speed of the rotating tool on the back surface B side than the moving speed of the rotating tool on the front surface A side, the heat input amount of the rotating tool on the back surface B side can be reduced. In addition, the length of the trajectory for moving the rotating tool (the sum of the lengths of the friction agitation trajectory) is made shorter on the back surface B side than the front surface A side of the metal member 1 to be joined, so that the amount of heat input on the back surface B side. Can be reduced. The friction agitation performed in the second main joining step may be set in consideration of the heat input amount, the heat removal amount, the size of the gap P in the first main joining step, the thickness of the metal member 1 to be joined, and the like. .

  In addition, after the first main joining step and the second main joining step, if the warped metal member 1 remains warped, a correction step is performed from the front surface A or the back surface B of the metal member 1 to be joined. Also good. In the correction step, friction agitation is performed from the convex surface side of the front surface A or the rear surface B of the bonded metal member 1 using a correction rotation tool (not shown). As the correction rotary tool, a correction rotary tool (not shown) smaller than the first main joining rotary tool G is used. The movement path of the friction stirrer is not particularly limited, and may be performed on the abutting portion, or may be performed on a portion where warpage is large.

  Moreover, when the groove | channel formed by friction stirring becomes large after a 2nd main joining process, you may repair by performing build-up welding to the said groove | channel. Alternatively, the lid member may be disposed in the groove and repaired by joining the lid member and the metal member 1 to be joined by friction stirring or the like.

DESCRIPTION OF SYMBOLS 1 Joining metal member 1a Metal member 1b Metal member 2 1st tab material 3 2nd tab material J1-J3 Abutting part A surface B back surface C 1st side surface D 2nd side surface H Temporary joining rotation tool H1 shoulder H2 stirring pin G 1st One main rotating tool G1 shoulder G2 stirring pin F Second main rotating tool F1 shoulder F2 stirring pin W1, W2 Plasticization region

Claims (5)

A first main joining step of performing frictional stirring from the surface side of the metal member by relatively moving the first rotating tool provided with the stirring pin and the shoulder with respect to the abutting portion between the metal members;
A second main joining step in which friction stirring is performed from the back side of the metal member by relatively moving a second rotating tool provided with a stirring pin with respect to the abutting portion, and a joining method including:
A spiral groove is engraved on the outer peripheral surface of the stirring pin of the second rotary tool, and when the second rotary tool is rotated clockwise, the spiral groove is turned counterclockwise as it goes from the proximal end to the distal end. When the second rotating tool is rotated counterclockwise, the spiral groove is formed clockwise as it goes from the proximal end to the distal end.
In the first main joining step, the stirring pin of the rotated first rotating tool is inserted into the abutting portion, and friction stirring is performed in a state where the stirring pin and the shoulder are in contact with the metal member,
Measure the deformation of the metal member after the first main joining step,
And in the second of the welding process, the stirring with the stirring pin of rotation and said second rotary tool the insert into butting portion performs friction stir only the stirring pin being in contact with the metal member Friction stirring is performed while adjusting the insertion depth of the pin in accordance with the deformation amount .   The joining method according to claim 1, wherein an amount of heat input by friction stirring in the second main joining step is smaller than an amount of heat input by friction stirring in the first main joining step. In the second of the welding process, according to claim 1, characterized in that performing the friction stir while entering the stirring pin of the said the first plasticized region formed in the welding process a second rotary tool or The joining method according to claim 2 . The joining method according to any one of claims 1 to 3 , further comprising a temporary joining step of temporarily joining the metal members before performing the main joining step. After providing a pilot hole on a tab member disposed on the side of the butting portion, either by inserting the stirring pin in the lower hole of claims 1 to 4, characterized in that performing the main bonding step The joining method according to claim 1.

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