JP6658469B2 - Friction stir welding method - Google Patents

Description

  The present invention relates to a friction stir welding method.

  In the prior art described in Patent Literature 1, friction stir welding is performed by abutting metal members in an L-shape in cross section and relatively moving a rotating tool along an inner corner.

JP 2015-120203 A

  In the prior art, since only the stirring pin of the rotary tool is inserted into the inner corner, the plasticized fluidized metal overflows to the outside, and there is a possibility that the joint (plasticized region) becomes insufficient in metal.

  Therefore, an object of the present invention is to provide a friction stir welding method that can prevent a shortage of metal at a joint at an inner corner.

  In order to solve the above-mentioned problem, the present invention is a friction stir welding method for joining a first metal member and a second metal member using a full-joint rotary tool having a stirring pin, wherein the first metal member And butting the second metal member whose surface height changes to form an inner corner formed by the end face of the first metal member and the surface of the second metal member, while the height changes. Abutting step of forming a portion, an arranging step of arranging an auxiliary member along the inner corner, and inserting the stirring pin of the rotating tool for full joining rotating into the inner corner, and only the stirring pin is A main joining step of performing friction stir welding along the inner corner in a state in which the first metal member, the second metal member, and the auxiliary member are in contact with each other.

  According to such a friction stir welding method, in addition to the first metal member and the second metal member, the auxiliary member is friction stir welded in a state of being in contact with the stirring pin. Also, it is possible to suitably join even at the inner corner where the height of the butted portion changes.

  Preferably, the method further includes a removing step of removing the burrs formed from the first metal member and the second metal member.

  According to the friction stir welding method, the burrs can be removed together with the auxiliary members.

  In the main joining step, it is preferable to set joining conditions such that burrs generated by friction stirring are formed on the auxiliary member.

  According to this friction stir welding method, burrs can be concentrated on the auxiliary member, so that burrs can be more easily removed.

  In the arranging step, the auxiliary member is brought into surface contact with the surface of the second metal member, and the auxiliary member is arranged such that the surface of the auxiliary member is lower than the surface of the first metal member. Is preferred. In the arranging step, the auxiliary member is brought into surface contact with an end surface of the first metal member, and the auxiliary member is arranged such that an end surface of the auxiliary member is at a position higher than a surface of the first metal member. Is preferred.

  According to the friction stir welding method, the auxiliary member can be easily removed.

  Before the main joining step, only the stirring pin of the temporary joining rotary tool is inserted into the inner corner, and at least one of the first metal member and the second metal member and the auxiliary member are spotted. It is preferable to include a temporary joining step of performing friction stir welding.

  According to such a friction stir welding method, the amount of heat input can be reduced, so that the thermal distortion of the first metal member and the second metal member can be reduced, and the temporary joining step can be performed in a short time. .

  In addition, it is preferable that the rotating tool for temporary joining and the rotating tool for final joining are the same rotating tool.

  According to such a friction stir welding method, it is not necessary to change the rotating tool for each process, so that the welding cycle can be shortened.

  ADVANTAGE OF THE INVENTION According to the friction stir welding method which concerns on this invention, shortage of metal in the joining part of an inner corner can be prevented.

It is a perspective view showing the preparation process of the friction stir welding method concerning a first embodiment of the present invention. FIG. 4 is a perspective view illustrating a butting step of the friction stir welding method according to the first embodiment. It is a perspective view showing an arrangement process of a friction stir welding method concerning a first embodiment. It is a perspective view showing the temporary joining process of the friction stir welding method concerning a first embodiment. It is sectional drawing which shows the temporary joining process of the friction stir welding method concerning 1st embodiment. It is a perspective view which shows the main joining process of the friction stir welding method concerning 1st embodiment. It is sectional drawing which shows the main joining process of the friction stir welding method concerning 1st embodiment. It is sectional drawing which shows the removal process of the friction stir welding method concerning 1st embodiment. It is a perspective view showing a butting process of a friction stir welding method concerning a second embodiment of the present invention. It is a perspective view showing an arrangement process of a friction stir welding method concerning a second embodiment. It is sectional drawing which shows the arrangement | positioning process of the friction stir welding method concerning 2nd embodiment. It is a perspective view showing the temporary joining process of the friction stir welding method concerning a second embodiment. It is sectional drawing which shows the temporary joining process of the friction stir welding method concerning 2nd embodiment. It is sectional drawing which shows the main joining process of the friction stir welding method concerning 2nd embodiment. It is sectional drawing which shows the removal process of the friction stir welding method concerning 2nd embodiment.

[First embodiment]
The friction stir welding method according to the first embodiment of the present invention will be described in detail with reference to the drawings. In the first embodiment, two metal members having different thicknesses (a first metal member and a second metal member) are joined. Both the first metal member and the second metal member have a convex portion on the surface, and the height of the surface changes. In the friction stir welding method according to the present embodiment, a preparation step, a butt step, an arrangement step, a temporary joining step, a main joining step, and a removing step are performed. In the following description, “front surface” means a surface opposite to “back surface”.

  The preparation step is a step of preparing a first metal member 10 and a second metal member 20 having different thicknesses, as shown in FIG. The first metal member 10 and the second metal member 20 are plate members made of an aluminum alloy. The material of the first metal member 10 and the second metal member 20 is appropriately selected from friction stirable metals such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy.

  The first metal member 10 includes a main body 11 having a rectangular parallelepiped shape, and a convex portion 12 formed on the main body 11 and having a trapezoidal cross section. The protrusion 12 is arranged at the center of the main body 11. The surface 12a of the projection 12 is located higher than the surfaces 11a and 11b of the main body 11. The first inclined surface 12b of the projection 12 is a portion corresponding to the oblique side of the trapezoid, and connects the surface 11a of the main body 11 and the surface 12a of the projection 12. Further, the second inclined surface 12c of the convex portion 12 is a portion corresponding to the oblique side of the trapezoid, and connects the surface 11b of the main body portion 11 and the surface 12a of the convex portion 12.

  The second metal member 20 includes a main body 21 having a rectangular parallelepiped shape, and a convex portion 22 formed on the main body 21 and having a trapezoidal cross section. The protrusion 22 is disposed at the center of the main body 21. The thickness of the main body 21 of the second metal member 20 is smaller than the thickness of the main body 11 of the first metal member 10. The shape of the protrusion 22 is the same as that of the protrusion 12. The surface 22a of the projection 22 is located higher than the surfaces 21a and 21b of the main body 21. The first inclined surface 22b of the projection 22 is a portion corresponding to the oblique side of the trapezoid, and connects the surface 21a of the main body 21 and the surface 22a of the projection 22. The second inclined surface 22c of the convex portion 22 is a portion corresponding to the trapezoidal oblique side portion, and connects the surface 21b of the main body portion 21 and the surface 22a of the convex portion 22.

  The butting step is a step of butting the first metal member 10 and the second metal member 20. In the butting process, as shown in FIGS. 1 and 2, the end face 10 a of the first metal member 10 and the end face 20 a of the second metal member 20 are butted. At this time, since the back surface (lower surface) 10c of the first metal member 10 and the back surface (lower surface) 20c of the second metal member 20 are flush, each surface (upper surface) 11a of the main body 11 of the first metal member 10 is formed. , 11b are located above the respective surfaces (upper surfaces) 21a, 21b of the main body 21 of the second metal member 20. Also, each surface (upper surface) 12a, 12b, 12c of the convex portion 12 of the first metal member 10 is located above each corresponding surface (upper surface) 22a, 22b, 22c of the corresponding convex portion 22 of the second metal member 20. positioned. The side surface 10d of the first metal member 10 and the side surface 20d of the second metal member 20 are flush.

  In the butting process, the end faces 10a and 20a are in surface contact to form the butted portion J1. The butting portion J1 is formed such that its height position changes. The end of the butted portion J1 (the upper end in the thickness direction of the second metal member 20) is formed by the end face 10a of the first metal member 10 and the surfaces 21a, 22b, 22a, 22c, 21b of the second metal member 20. An inner corner is formed. Assuming that the height (elevation) of the start point (insertion position) of the friction stir is the reference height, the inner corner has sections having different heights from the reference point from the start point to the end point. In the present embodiment, the inner corner is constituted by a first flat portion Ca, a first inclined portion Cb, a second flat portion Cc, a second inclined portion Cd, and a third flat portion Ce.

  In the butting process, the tab materials T, T are arranged. The tab material T has the same thickness as the thickness of the main body 21 of the second metal member 20. In the butting process, the tab materials T, T are arranged at both ends in the extending direction of the inner corner. The surface Ta of the tab material T is flush with the surfaces 21a and 21b of the second metal member 2. The back surface Tb of the tab material T is flush with the back surface 10c of the first metal member 1 and the back surface 20c of the second metal member 2.

  The arranging step is a step of arranging the auxiliary member 30 in the inner corner. As shown in FIG. 2, the auxiliary member 30 is a metal material and has a plate shape. The auxiliary member 30 is preferably made of the same material as the first metal member 10 and the second metal member 20. The auxiliary member 30 has a shape that comes into surface contact with the surface of the second metal member 20. The thickness of the auxiliary member 30 is set to such an extent that metal shortage does not occur in the joint (plasticized region) after the main joining step.

  In the disposing step, the side surface 30c of the auxiliary member 30 is abutted against the end surface 10a of the first metal member 10, and the back surface 30b of the auxiliary member 30 is brought into surface contact with the surface of the second metal member 20, as shown in FIG. The surface 30a of the auxiliary member 30 is at a position lower than the surface of the first metal member 10.

  As shown in FIG. 4, the temporary joining step is a step of temporarily joining inner corners using a rotating tool F (a rotating tool for temporary joining). The rotating tool F is formed of, for example, tool steel. The rotating tool F includes a connecting portion F1 and a stirring pin F2. The connection part F1 is a part connected to the rotating shaft of the friction stirrer. The connecting portion F1 has a columnar shape.

  The stirring pin F2 extends from the connecting portion F1 and is coaxial with the connecting portion F1. The stirring pin F2 tapers as it moves away from the connecting portion F1. A spiral groove is engraved on the outer peripheral surface of the stirring pin F2. In the first embodiment, in order to rotate the rotating tool F clockwise, the spiral groove is formed counterclockwise from the base end toward the distal end.

  When rotating the rotating tool F counterclockwise, it is preferable that the spiral groove is formed clockwise from the base end toward the tip end. By setting the spiral groove in this way, the metal plastically fluidized at the time of friction stirring is guided to the tip side of the stirring pin F2 by the spiral groove. Thereby, the amount of metal overflowing outside the metal members to be joined (the first metal member 10, the second metal member 20, and the auxiliary member 30) can be reduced.

  In the temporary joining step, as shown in FIG. 5, spot agitation is performed by bringing only the stirring pin F2 of the rotating tool F rotated clockwise into contact with the inner corner of the end of the butted portion J1. In the temporary joining step, only the stirring pin F2 is pushed into the butting portion J1 shallowly at a predetermined interval. At this time, the rotating tool F is inclined so that the stirring pin F2 does not interfere with the upper part of the end face 10a of the first metal member 10. The rotating tool F is inclined so that the connecting portion F1 is on the second metal member 20 side. A point-like plasticized region W1 is formed at the press mark of the stirring pin F2.

  It is preferable that the rotating tool F is attached to an arm robot (not shown) provided with a rotation driving unit such as a spindle unit at the tip. Thereby, the rotation center axis of the rotation tool F can be inclined, so that the spot temporary attachment at the inner corner can be easily performed.

  In the temporary joining step, spot temporary attachment is also performed on the butting portion between the first metal member 10 and the tab material T and the butting portion between the second metal member 20 and the tab material T. The metal member 10 and the second metal member 20 are temporarily joined.

  As shown in FIG. 6, the main joining step is a step of performing friction stir welding on the inner corner of the butt portion J1 using the rotary tool F (rotary tool for main joining). In the main joining step, after inserting the right-rotated rotating tool F into the start position Sp set on one of the tab materials T, the rotating tool F is relatively moved along the inner corner of the butted portion J1. In the main joining process, the setting is made so that the auxiliary member 30 is located on the right side in the traveling direction of the rotary tool F. In the main joining step, only the stirring pin F2 is brought into contact with the first metal member 10, the second metal member 20, and the auxiliary member 30, and friction stir welding is performed with the base end side of the stirring pin F2 exposed.

  On the tab material T, the rotating tool F is moved in a state where the rotation center axis of the rotating tool F is orthogonal to the surface Ta of the tab material T. When the rotating tool F moves to the vicinity of the inner corner, the rotating tool F is inclined toward the second metal member 20 (the metal member having a lower surface). As shown in FIG. 7, in the present embodiment, the rotation center axis of the rotary tool F is inclined by about 45 to 60 ° with respect to the surface 22a of the second metal member 20, and the tip of the stirring pin F2 is The abutting surface of the first metal member 10 and the second metal member 20 (the contact surface between the end surface 10a of the first metal member 10 and the end surface 20a of the second metal member 20) is not too far away.

  When the rotating tool F moves away from the inner corner and moves on the other tab material T, the rotation center axis of the rotating tool F is returned to a state orthogonal to the surface Ta of the tab material T. When the rotating tool F reaches the end position set on the other tab material T, the rotating tool F is separated from the tab material T. Through the above steps, the plasticized region W2 is formed on the movement trajectory of the rotary tool F.

  In the main joining step according to the first embodiment, only the stirring pin F2 is connected to the first metal member 10, the second metal member 20, and the auxiliary member while maintaining the insertion depth of the stirring pin F2 in the inner corner of the butted portion J1 substantially constant. Friction agitation is performed in a state where the member is in contact with the member 30. When the end face 10a of the first metal member 10 is viewed from the front, the rotary tool F is relatively moved so that the rotation center axis of the rotary tool F and the vertical direction are parallel to each other.

  In the main joining step according to the first embodiment, friction stirring is performed by vertically moving the rotary tool F with respect to a mount (not shown) to which the first metal member 10 and the second metal member 20 are fixed. Thereby, the depth of the plasticized region W2 can be made substantially equal. The “insertion depth” of the stirring pin F2 means the distance from the surface of the second metal member 20 on the rotation center axis of the rotating tool F to the tip of the stirring pin F2.

  In the main joining step according to the first embodiment, the rotary tool F is moved up and down with respect to the gantry (not shown). However, the height position of the rotary tool F is fixed and the gantry is moved up and down. Friction stirring may be performed.

  As shown in FIGS. 6 and 7, in the main joining step, the rotation direction and the traveling direction of the rotary tool F are set such that the auxiliary member 30 is positioned on the right side in the traveling direction while rotating the rotary tool F clockwise. For example, when the rotation speed of the rotating tool F is low, the shear side (advancing side: the rotating tool) is compared with the retreating side (the side on which the moving speed of the rotating tool is subtracted from the tangential speed on the outer periphery of the rotating tool). Since the temperature of the plastic fluid material is more likely to increase on the side where the moving speed of the rotating tool is added to the tangential speed on the outer periphery (the side where the moving speed of the rotating tool is added), a large amount of burrs V tend to occur on the shear side outside the plasticizing region W2. On the other hand, for example, when the rotation speed of the rotary tool F is high, although the temperature of the plastic flow material increases on the shear side, a lot of burrs V are generated on the flow side outside the plasticization region W2 due to the high rotation speed. There is a tendency.

  In the present embodiment, since the rotation speed of the rotary tool F is set to be high, a large amount of burrs V tend to be generated on the flow side outside the plasticizing region W2, as shown in FIG. That is, the burrs V can be concentrated on the auxiliary member 30. Further, by setting the rotation speed of the rotary tool F high, the moving speed (feed speed) of the rotary tool F can be increased. Thereby, the joining cycle can be shortened.

  At the time of the friction stir process, which side of the traveling direction of the rotary tool F generates the burr V depends on the joining conditions. The joining conditions include the rotation speed, rotation direction, moving speed (feed speed) of the rotary tool F, the inclination angle (taper angle) of the stirring pin F2, the first metal member 10, the second metal member 20, and the auxiliary member 30. It is determined by each element such as the material and the thickness of the auxiliary member 30 and the combination of these elements. It is preferable that the side on which burrs V occur or the side on which many burrs V occur are set to the auxiliary member 30 side in accordance with the joining conditions, since the removal step described later can be easily performed, which is preferable.

  The removing step is a step of removing the auxiliary member 30 from the first metal member 10 and the second metal member 20, as shown in FIG. In the removing step, the auxiliary member 30 is cut off in such a manner as to be bent in a direction away from the second metal member 20. The removal step may be performed by a cutting device or the like, but is manually performed in the present embodiment.

  According to the friction stir welding method according to the first embodiment described above, in addition to the first metal member 10 and the second metal member 20, the auxiliary member 30 is friction stir welded while being in contact with the stirring pin F2. Insufficient metal at the joint (plasticized region W2) can be prevented. Further, since the shape of the auxiliary member 30 is formed according to the shape of the surface of the second metal member 20, it is possible to suitably join even at the inner corner where the height of the butted portion J1 changes.

  Further, according to the present embodiment, the auxiliary member 30 in which the burrs V are concentrated can be removed from the first metal member 10 and the second metal member 20. According to this, the burr V can be easily removed together with the auxiliary member 30.

  Further, since the temporary joining step is performed by spot temporary attachment as in the present embodiment, the heat input can be reduced. Thereby, thermal distortion of the first metal member 10 and the second metal member 20 can be reduced. Further, according to the present embodiment, the temporary joining step can be performed in a short time. The same rotary tool F is used in the temporary joining step and the main joining step. This eliminates the need to replace the rotating tool in each step, thereby improving work efficiency.

  Also, in the main joining process, the frictional stir welding is performed in a state where only the stirring pin F2 is in contact with the first metal member 10, the second metal member 20, and the auxiliary member 30, thereby reducing the load acting on the friction stirrer. In this state, a deep position of the butted portion J1 can be joined. Furthermore, since only the stirring pin F2 is inserted in both the temporary joining step and the main joining step, the amount of heat input can be further suppressed, and the thermal distortion can be reduced.

  In addition, in the main joining step, friction stir is performed while keeping the insertion depth of the stirring pin F2 into the inner corner of the butting portion J1 whose height changes, so that the joining strength of the joining portion is kept almost constant. be able to.

  Although the first embodiment of the present invention has been described above, design changes can be made as appropriate without departing from the spirit of the present invention. For example, different rotating tools may be used in the temporary joining step and the main joining step. In the present embodiment, in the main joining step, when the end face 10a of the first metal member 10 is viewed from the front, friction stir welding is performed so that the rotation center axis of the rotary tool F and the vertical direction are parallel. . In the final joining step, when the end face 10a of the first metal member 10 is viewed from the front, the final joining is performed while the rotation center axis of the rotary tool F is perpendicular to the first inclined surface 22b and the second inclined surface 22c. The depth of the plasticized region W2 in the process may be adjusted to be constant. In the temporary joining step, welding may be performed instead of friction stirring. Although the type of welding is not limited, for example, laser welding, TIG welding, or MIG welding can be used. In the temporary joining step, the first metal member 10, the second metal member 20, and the auxiliary member 30 are spot-temporarily attached. However, only the first metal member 10 and the auxiliary member 30 may be temporarily attached.

[Second embodiment]
Next, a friction stir welding method according to a second embodiment of the present invention will be described. In the friction stir welding method according to the second embodiment, a preparation step, a butt step, an arrangement step, a temporary joining step, a main joining step, and a removing step are performed. In the friction stir welding method according to the second embodiment, the method of arranging the auxiliary member is different from that of the first embodiment. In the second embodiment, a description will be given focusing on portions different from the first embodiment. As shown in FIG. 9, the preparation step and the butting step are common to the first embodiment.

  The arranging step is a step of arranging the auxiliary member 40. The auxiliary member 40 is a plate-shaped member made of the same material as the first metal member 10 and the second metal member 20. A notch 41 is formed at a lower portion of the auxiliary member 40. The notch 41 has a shape that comes into contact with the projection 22 of the second metal member 20 without a gap. In the arrangement step, as shown in FIGS. 10A and 10B, the auxiliary member 40 is arranged upright along the inner corners of the first metal member 10 and the second metal member 20.

  In the arranging step, as shown in FIG. 10B, while the surface 40 a of the auxiliary member 40 is in surface contact with the end surface 10 a of the first metal member 10, the one end surface 40 d of the auxiliary member 40 and the surface of the second metal member 20 are Abut. The other end surface 40 c of the auxiliary member 40 is located above the surface of the first metal member 10.

  As shown in FIG. 11, the temporary joining step is a step of temporarily joining inner corners using a rotating tool F (rotating tool for temporary joining). In the temporary joining step, spot stirring is performed by bringing only the stirring pin F2 of the rotating tool F that has been rotated left into contact with the inner corner of the end of the butted portion J1. In the temporary joining step, only the stirring pin F2 is pushed into the butting portion J1 shallowly at a predetermined interval. As shown in FIG. 12, the rotating tool F is inclined such that the connecting portion F1 is on the second metal member 20 side. A plasticized region W1 is formed at the push mark of the stirring pin F2.

  As shown in FIG. 13, the main joining step is a step of performing friction stir welding on the inner corner of the butt portion J1 using the rotary tool F (rotary tool for main joining). In the main joining step of the present embodiment, the auxiliary member 40 is positioned on the left side in the traveling direction, and the rotating tool F is rotated counterclockwise. Accordingly, the right side in the traveling direction of the rotating tool F is the shear side, and the left side is the flow side. In the present embodiment, in order to rotate the rotary tool F at a high speed, burrs V generated by friction stirring are collected in the auxiliary member 40.

  The removing step is a step of removing the auxiliary member 40 from the first metal member 10 and the second metal member 20, as shown in FIG. In the removing step, the auxiliary member 40 is cut off so as to be bent in a direction away from the first metal member 10. The removal step may be performed by a cutting device or the like, but is manually performed in the present embodiment.

  With the friction stir welding method according to the second embodiment described above, substantially the same effects as in the first embodiment can be obtained. In the arrangement step of the present embodiment, the other end surface 40c of the auxiliary member 40 is located above the surface of the first metal member 10, so that the auxiliary member 40 can be easily bent. Thereby, the removal step can be easily performed. In the temporary joining step, the first metal member 10, the second metal member 20, and the auxiliary member 40 are spot-temporarily attached, but only the second metal member 20 and the auxiliary member 40 may be temporarily attached.

  Although the embodiments of the present invention have been described above, design changes can be made as appropriate without departing from the spirit of the present invention. For example, the first metal member and the second metal member may have different shapes. Further, the first metal member and the second metal member may be abutted by shifting members having the same shape. Prior to the temporary joining step, preliminary joining may be performed on the butted portion J1 of the first metal member 10 and the second metal member 20 by friction stirring or welding. The pre-joining may be an entire joining of the butted portions J1 or a spot temporary joining. Thereby, the opening of the first metal member 10 and the second metal member 20 can be prevented in the arrangement step and the temporary joining step.

Reference Signs List 10 first metal member 20 second metal member F rotary tool (rotary tool for temporary bonding, rotary tool for final bonding)
F2 Stirring pin J1 Butt T tab material W1 Plasticized area W2 Plasticized area

Claims (7)

A friction stir welding method for joining the first metal member and the second metal member using the main joining rotary tool having a stirring pin,
Abutting the first metal member and the second metal member whose surface height changes, while forming an inner corner formed by the end surface of the first metal member and the surface of the second metal member, A butting process of forming a butting portion having a variable
An arranging step of arranging an auxiliary member along the inner corner,
Inserting the stirring pin of the rotating tool for full rotation rotating into the inner corner, the inner corner in a state where only the stirring pin is in contact with the first metal member, the second metal member and the auxiliary member. And a main joining step of performing friction stir welding along the line.   The friction stir welding method according to claim 1, further comprising a removing step of removing the burr-formed auxiliary member from the first metal member and the second metal member.   3. The friction stir welding method according to claim 2, wherein in the main welding step, welding conditions are set such that burrs generated by friction stirring are formed on the auxiliary member.   In the arranging step, the auxiliary member is brought into surface contact with the surface of the second metal member, and the auxiliary member is arranged such that the surface of the auxiliary member is lower than the surface of the first metal member. The friction stir welding method according to claim 2 or 3, wherein:   In the arranging step, the auxiliary member is brought into surface contact with the end surface of the first metal member, and the auxiliary member is arranged such that the end surface of the auxiliary member is located at a position higher than the surface of the first metal member. The friction stir welding method according to claim 2 or 3, wherein: Before the main joining step, insert only the stirring pin of the rotating tool for temporary joining into the inner corner,
6. The method according to claim 1, further comprising a temporary joining step of friction stir welding at least one of the first metal member and the second metal member and the auxiliary member at a spot. 7. 3. The friction stir welding method according to 1.   The friction stir welding method according to claim 6, wherein the rotating tool for temporary welding and the rotating tool for final welding are the same rotating tool.

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