JP2019202321A - Welding method - Google Patents

Abstract

To provide a welding method which can easily subject a superimposed part of superimposed metal members to friction stir welding even if the part is in a deep position and achieve high welding strength.SOLUTION: The welding method includes a superimposing step of superimposing a rear face 1c of a first metal member 1 with a front face 2b of a second metal member 2 to form a superimposed part J and a friction stirring step of subjecting the superimposed part J to friction stir welding by inserting a stirring pin G2 of a rotating tool G into a recessed groove 3, where an outer peripheral surface of the stirring pin G2 is inclined to taper, a flat surface G3 is formed at a tip side of the stirring pin G2 and a protruding part G4 protruding to the flat surface G3 is formed at the tip side. In the friction stirring step, the flat surface G3 is made to contact only with the first metal member 1 while pressing burr V by a shoulder part G1 in a state where a shoulder part G1 is inserted into the recessed groove 3 and the shoulder part G1 is separated from a bottom surface 3a of the recessed groove 3, and the superimposed part J is subjected to friction stir welding in a state where the protrusion part G4 is made to contact with the second metal member 2.SELECTED DRAWING: Figure 3

Description

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

  Patent Document 1 discloses a bonding method in which a first metal member and a second metal member are overlapped and bonded. In the joining method, a superposition process is formed by superimposing the back surface of the first metal member and the front surface of the second metal member, and a superposition part is friction stir welded by pushing a rotary tool from the surface of the first metal member. And a friction stirring step.

JP 2017-185501 A

  In this field, a bonding method with higher bonding strength is desired.

  From such a viewpoint, the present invention provides a joining method that can easily perform friction stir welding and has high joining strength even when the overlapped portion of the overlapped metal member is located at a deep position. Let it be an issue.

  In order to solve such a problem, the present invention provides a polymerization step in which a back surface of a first metal member having a concave groove on the surface and a surface of a second metal member are overlapped to form a superposition part, Inserting a stirring pin of a rotary tool into the concave groove from the surface side of the metal member, and relatively moving the rotary tool along the concave groove, and a friction stirring step of friction stir welding the overlapped portion, The rotating tool includes a shoulder portion having a cylindrical shape and the stirring pin hanging from the shoulder portion, the diameter of the shoulder portion is set smaller than the width of the concave groove, and the outer peripheral surface of the stirring pin is tapered. A flat surface is formed on the tip end side of the stirring pin, and a protrusion protruding to the flat surface is formed, and in the friction stirring step, the rotating tool has the In front of shoulder With the shoulder portion being spaced from the bottom surface of the groove, the burr generated from the first metal member is pressed by the shoulder portion, and the flat surface is only the first metal member. In addition, the overlapping portion is friction stir welded in a state where the protruding portion is in contact with the second metal member.

  In addition, the present invention provides a polymerization step in which the back surface of the first metal member having a concave groove on the surface and the surface of the second metal member are overlapped to form a polymerization portion, and from the surface side of the first metal member, A friction stirring step of inserting a stirring pin of a rotary tool into the concave groove and relatively moving the rotary tool along the concave groove to friction stir weld the overlapping portion, and the concave groove becomes a closed loop. The rotating tool has a shoulder portion having a columnar shape and the stirring pin hanging from the shoulder portion, the diameter of the shoulder portion is set smaller than the width of the groove, and the stirring pin The outer peripheral surface is inclined so as to be tapered, and a flat surface is formed on the tip side of the stirring pin, and a protruding portion protruding from the flat surface is formed.In the friction stirring step, The rotation tool With the shoulder portion inserted into the groove, the burr generated from the first metal member is pressed by the shoulder portion while the shoulder portion is separated from the bottom surface of the groove, and the flat surface is The overlapping portion is friction stir welded in a state where only one metal member is brought into contact with and the projection is in contact with the second metal member. Furthermore, in the friction stirring step, it is preferable that the rotating tool is caused to make a round along the concave groove and the overlapped portion is friction stir welded.

  According to such a joining method, since the shoulder portion is not pushed into the bottom surface of the concave groove, the load applied to the friction stirrer can be reduced. That is, according to the present invention, since the load on the friction stirrer can be reduced, the superposed portion at a deep position can be easily friction stir welded. In addition, a flat surface is formed on the tip side of the agitating pin, and a protruding portion protruding from the flat surface is formed. Therefore, the plastic fluidized material that is frictionally stirred along the protruding portion and wound up on the protruding portion. Is held down on a flat surface. Accordingly, the periphery of the protrusion can be more reliably frictionally stirred and the oxide film between the metal members can be reliably divided, so that the bonding strength can be increased.

  According to the joining method according to the present invention, it is possible to easily perform friction stir welding and increase the joining strength even when the overlapped portion of the overlapped metal members is at a deep position.

It is a perspective view which shows the superposition | polymerization process of the joining method which concerns on 1st embodiment of this invention. It is a perspective view which shows the friction stirring process of the joining method which concerns on 1st embodiment. It is sectional drawing which shows the friction stirring process of the joining method which concerns on 1st embodiment. It is a perspective view which shows the superposition | polymerization process of the joining method which concerns on 2nd embodiment. It is a top view which shows the friction stirring process of the joining method which concerns on 2nd embodiment.

[First embodiment]
A joining method according to a first embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, in the joining method according to the first embodiment, the first metal member 1 and the second metal member 2 are overlapped and joined. The joining method according to the first embodiment performs a polymerization process, a tab material arranging process, and a friction stirring process. In the description, “front surface” means a surface opposite to the “back surface”.

  The first metal member 1 is a plate-like metal member. The material of the first metal member 1 is appropriately selected from metals capable of friction stir such as aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, magnesium alloy and the like. A concave groove 3 having a rectangular cross section is formed on the surface 1 b of the first metal member 1. The concave groove 3 is extended in the extending direction of the first metal member 1. The concave groove 3 includes a bottom surface 3a and side walls 3b and 3b rising from the bottom surface 3a.

  The second metal member 2 is a plate-like metal member. The material of the second metal member 2 may be appropriately selected from the metals that can be frictionally stirred, but is preferably the same material as that of the first metal member 1. The second metal member 2 has the same shape as the first metal member 1, but may have a different shape. In addition, the first metal member 1 and the second metal member 2 each have a plate shape (cuboid) in the present embodiment, but may be a polygonal shape other than a plan view, and may be a circular shape or an oval shape in plan view. It may be.

  As shown in FIG. 1, the polymerization step is a step of superposing the back surface 1 c of the first metal member 1 and the surface 2 b of the second metal member 2. The overlapping portion J is formed by overlapping the back surface 1c of the first metal member 1 and the surface 2b of the second metal member 2.

  The tab material arranging step is a step of arranging the tab materials T and T as shown in FIG. The tab material T has a rectangular parallelepiped shape. The tab material T is temporarily joined to the end surfaces 1a and 2a of the first metal member 1 and the second metal member 2 by welding so that the surface Ta of the tab material T and the bottom surface 3a of the groove 3 are flush with each other. .

  As shown in FIGS. 1 and 2, the friction stirring step is a step of inserting the shoulder portion G <b> 1 of the rotary tool G into the groove 3 and friction stir welding the overlapping portion J. The rotary tool G includes a cylindrical shoulder portion G1 and a stirring pin G2 that hangs down from the lower end surface G1a of the shoulder portion G1. The diameter of the shoulder portion G1 is slightly smaller than the width of the concave groove 3. The diameter of the shoulder portion G1 may be set so that the outer peripheral surface of the shoulder portion G1 and the side walls 3b, 3b of the groove 3 are in contact with each other. It is preferable that the side walls 3b and 3b of the recessed groove 3 have dimensions that allow relative movement with a slight gap.

  The stirring pin G2 is tapered as it is separated from the shoulder portion G1. As shown in FIG. 3, a flat surface G3 that is perpendicular to the rotation center axis C and is flat is formed at the tip of the stirring pin G2. Further, a projection G4 projecting downward is formed on the flat surface G3. The protruding portion G4 is a portion that protrudes downward from the central portion of the flat surface G3. The shape of the protrusion G4 is not particularly limited, but in the present embodiment, it is a columnar shape.

  A step portion is formed by the side surface of the projection G4 and the flat surface G3. That is, the outer surface of the stirring pin G2 is configured by the outer peripheral surface G10 that is tapered, the flat surface G3 formed at the tip, and the outer peripheral surface and the tip surface G5 of the protrusion G4. A spiral groove is formed on the outer peripheral surface G10 of the stirring pin G2. In this embodiment, in order to rotate the rotary tool G to the right, the spiral groove of the stirring pin G2 is formed counterclockwise as it goes from the proximal end to the distal end. In other words, the spiral groove is formed counterclockwise as viewed from above when the spiral groove is traced from the proximal end to the distal end.

  In addition, when rotating the rotation tool G counterclockwise, it is preferable to form the spiral groove clockwise as it goes from the proximal end to the distal end. In other words, the spiral groove in this case is formed clockwise when viewed from above when the spiral groove is traced from the proximal end to the distal end. By setting the spiral groove in this manner, the plastic fluidized metal in the friction stirring step is guided to the tip side of the stirring pin G2 by the spiral groove. Thereby, the quantity of the metal which overflows from the bottom face 3a of the ditch | groove 3 can be decreased. A spiral groove may be formed on the side surface of the protrusion G4.

  In the friction stirring step, as shown in FIGS. 1 and 2, the stirring pin G2 of the rotary tool G is inserted into the start position Sp1 set on the surface Ta of one tab member T, and the surface Ta of the other tab member T is inserted. The rotary tool G is relatively moved along the overlapped portion J (concave groove 3) to the end position Ep1 set to. The insertion depth of the rotary tool G may be set as appropriate. In this embodiment, as shown in FIG. 3, the flat surface G3 of the stirring pin G2 is brought into contact with only the first metal member 1, and the protrusion G4 is formed. Friction stirring is performed with the front end surface G5 in contact with only the second metal member 2. In other words, in the friction stirring step, the insertion depth of the stirring pin G2 is set so that the side surface of the protruding portion G4 is positioned at the overlapping portion J. A plasticized region W is formed in the movement locus of the rotary tool G.

  Further, in the friction stirring step, as shown in FIG. 3, the lower end surface G1a of the shoulder portion G1 is separated from the bottom surface 3a of the concave groove 3 and is set to a position lower than the surface 1b of the first metal member 1. ing. That is, in the friction stirring step, friction stir welding is performed while pressing the burr V generated by the friction stirring with the lower end surface G1a of the shoulder portion G1. “The state in which the shoulder portion is separated from the bottom surface of the concave groove” in the claims means that the lower end surface G1a of the shoulder portion G1 is separated from the bottom surface 3a of the concave groove 3 before the burr V is generated. It is. In addition, the phrase “while pressing the burr generated from the first metal member with the shoulder portion” in the claims means that the accumulated burr V and the lower end surface G1a of the shoulder portion G1 are in contact with each other. This means that the surface (upper surface) is pressed by the lower end surface G1a of the shoulder portion G1.

  Further, the outer peripheral surface of the shoulder portion G1 and the side walls 3b, 3b of the concave groove 3 are separated from each other with a slight gap. A narrow space is formed by the bottom surface 3a of the concave groove 3, the side walls 3b, 3b of the concave groove 3, and the lower end surface G1a of the shoulder portion G1.

  A burr V is generated on the bottom surface 3a of the groove 3 by the friction stir process. However, a narrow space (rectangular cross section) formed by the bottom surface 3a of the groove 3, the side walls 3b and 3b of the groove 3, and the lower end surface G1a of the shoulder portion G1. The burr V is confined in the closed space), and the burr V is deposited on the bottom surface 3a. As shown in FIG. 3, the burr V is accommodated in the concave groove 3, and the surface (upper surface) of the burr V is pressed by the lower end surface G1a of the shoulder portion G1 and becomes substantially flat. When the rotary tool G reaches the end position Ep1, the rotary tool G is detached from the tab material T and the tab materials T and T are cut off.

  According to the joining method according to the present embodiment described above, since the shoulder portion G1 is not pushed into the bottom surface 3a of the groove 3, the load applied to the friction stirrer can be reduced. Thereby, even if the superposition | polymerization part J exists in a deep position, friction stir welding can be performed easily. In addition, you may perform the temporary joining process which performs temporary joining with respect to the superposition | polymerization part J from the end surface 1a of the 1st metal member 1, and the end surface 2a of the 2nd metal member 2 before performing a friction stirring process. In this case, for example, temporary joining is performed on the overlapping portion J using a small temporary joining rotary tool. The temporary joining step may be performed by welding. By performing the temporary joining process, in the friction stirring process using the rotary tool G, the first metal member 1 and the second metal member 2 are less likely to be displaced and can be stably operated.

  Since the protruding portion G4 is formed on the flat surface G3 on the tip side of the stirring pin G2, the plastic fluid material frictionally stirred along the protruding portion G4 and wound up on the protruding portion G4 is pressed by the flat surface G3. As a result, the periphery of the protrusion G4 can be more reliably frictionally stirred and the oxide film of the overlapped portion J can be surely divided, so that the bonding strength of the overlapped portion J can be increased.

  Further, according to the joining method according to the present embodiment, a narrow space is formed by the bottom surface 3a of the recessed groove 3, the side walls 3b and 3b of the recessed groove 3, and the lower end surface G1a of the shoulder portion G1 when performing the friction stirring step. Therefore, it is possible to prevent the burrs V from being scattered and to deposit the burrs V on the bottom surface 3 a of the groove 3. Thereby, generation | occurrence | production of the burr | flash V on the surface 1b of the 1st metal member 1 can be prevented. Therefore, a surface treatment such as a deburring process on the surface 1b of the first metal member 1 can be omitted.

[Second Embodiment]
Next, the joining method according to the second embodiment of the present invention will be described. The joining method according to the present embodiment performs a polymerization process and a friction stirring process. The joining method according to the present embodiment is different from the first embodiment in that the tab material arranging step is omitted and the groove 3 is a closed loop. The joining method according to the second embodiment will be described with a focus on the differences from the first embodiment.

  As shown in FIG. 4, the first metal member 1 is a plate-like metal member. On the surface 1 b of the first metal member 1, a closed loop groove 3 is formed. The closed loop means that the concave groove 3 is closed so as to circulate. The planar shape of the groove 3 may be any shape as long as it is closed, but in the present embodiment, it is formed in a rectangular frame shape in plan view along the periphery of the first metal member 1.

  The second metal member 2 is a plate-like metal member. The second metal member 2 has the same shape as the first metal member 1, but may have a different shape. In addition, the first metal member 1 and the second metal member 2 each have a plate shape (cuboid) in the present embodiment, but may be a polygonal shape other than a plan view, and may be a circular shape or an oval shape in plan view. It may be. A groove or a recess may be formed on the surface 2 b of the second metal member 2. The groove or the recess is preferably formed so as to be located inside the groove 3 of the first metal member 1.

  As shown in FIG. 4, the polymerization step is a step of overlapping the back surface 1 c of the first metal member 1 and the surface 2 b of the second metal member 2. The overlapping portion J is formed by overlapping the back surface 1c of the first metal member 1 and the surface 2b of the second metal member 2.

  As shown in FIGS. 4 and 5, the friction stirring step is a step of inserting the shoulder portion G <b> 1 of the rotary tool G into the groove 3 and friction stir welding the overlapping portion J. In the friction stirring step, the stirring pin G2 of the rotary tool G is inserted into the start position Sp set in the concave groove 3, and the overlapping portion J is joined along the concave groove 3. A plasticized region W is formed in the movement locus of the rotary tool G. It is the same as in the first embodiment that the insertion depth of the stirring pin G2 and the burr V are pressed by the lower end surface G1a of the shoulder portion G1.

  When the rotating tool G makes a round along the concave groove 3, the start end and the terminal end of the plasticizing region W are overlapped, and the rotating tool G is detached from the first metal member 1 at the end position Ep set in the concave groove 3. Let

  According to the joining method according to the present embodiment described above, since the shoulder portion G1 is not pushed into the bottom surface 3a of the groove 3, the load applied to the friction stirrer can be reduced. Thereby, even if the superposition | polymerization part J exists in a deep position, friction stir welding can be performed easily. In addition, you may perform the temporary joining process which performs temporary joining with respect to the superposition | polymerization part J from the end surface 1a of the 1st metal member 1, and the end surface 2a of the 2nd metal member 2 before performing a friction stirring process. Further, in the friction stirring step, the rotating tool G may not be made to make one turn along the closed loop concave groove 3 (the start end and the end end of the plasticized region W are not overlapped).

  Since the protruding portion G4 is formed on the flat surface G3 on the tip side of the stirring pin G2, the plastic fluid material frictionally stirred along the protruding portion G4 and wound up on the protruding portion G4 is pressed by the flat surface G3. As a result, the periphery of the protrusion G4 can be more reliably frictionally stirred and the oxide film of the overlapped portion J can be surely divided, so that the bonding strength of the overlapped portion J can be increased.

  Further, according to the joining method according to the present embodiment, a narrow space is formed by the bottom surface 3a of the recessed groove 3, the side walls 3b and 3b of the recessed groove 3, and the lower end surface G1a of the shoulder portion G1 when performing the friction stirring step. Therefore, it is possible to prevent the burrs V from being scattered and to deposit the burrs V on the bottom surface 3 a of the groove 3. Thereby, generation | occurrence | production of the burr | flash V on the surface 1b of the 1st metal member 1 can be prevented. Therefore, a surface treatment such as a deburring process on the surface 1b of the first metal member 1 can be omitted. Further, by performing friction stir welding of the overlapped portion J along the closed loop concave groove 3, the bonding strength can be increased. Moreover, the area | region closed inside the concave groove 3 of a closed loop can be formed.

DESCRIPTION OF SYMBOLS 1 1st metal member 1b surface 1c back surface 2 2nd metal member 2b surface 2c back surface 3 concave groove J superposition | polymerization part G rotation tool G1 shoulder part G2 stirring pin G3 flat surface G4 protrusion part G5 front end surface V burr W plasticization area | region

Claims (3)

A polymerization step in which a back surface of the first metal member having a concave groove on the surface and a surface of the second metal member are overlapped to form a polymerization portion;
A friction stirring step of inserting a stirring pin of a rotary tool into the concave groove from the surface side of the first metal member, relatively moving the rotary tool along the concave groove, and friction stir welding the overlapping portion; Including
The rotating tool has a shoulder portion having a cylindrical shape and the stirring pin hanging from the shoulder portion, and sets the diameter of the shoulder portion to be smaller than the width of the concave groove,
The outer peripheral surface of the stirring pin is inclined so as to be tapered,
A flat surface is formed on the tip side of the stirring pin, and a protrusion protruding on the flat surface is formed,
In the friction stirring step, burrs generated from the first metal member are inserted into the concave groove of the rotating tool and the shoulder is separated from the bottom surface of the concave groove. The overlapping portion is friction stir welded while the flat surface is brought into contact with only the first metal member and the projection is in contact with the second metal member while being pressed by a portion. Method. A polymerization step in which a back surface of the first metal member having a concave groove on the surface and a surface of the second metal member are overlapped to form a polymerization portion;
A friction stirring step of inserting a stirring pin of a rotary tool into the concave groove from the surface side of the first metal member, moving the rotary tool relatively along the concave groove, and friction stir welding the overlapping portion; Including
Forming the concave groove to be a closed loop;
The rotating tool has a shoulder portion having a cylindrical shape and the stirring pin hanging from the shoulder portion, and sets the diameter of the shoulder portion to be smaller than the width of the concave groove,
The outer peripheral surface of the stirring pin is inclined so as to be tapered,
A flat surface is formed on the tip side of the stirring pin, and a protrusion protruding on the flat surface is formed,
In the friction stirring step, burrs generated from the first metal member are inserted into the concave groove of the rotating tool and the shoulder is separated from the bottom surface of the concave groove. The overlapping portion is friction stir welded while the flat surface is brought into contact with only the first metal member and the protrusion is in contact with the second metal member while being pressed by a portion. Method.   3. The joining method according to claim 2, wherein in the friction stirring step, the overlapping portion is friction stir welded by making the rotary tool make a round along the concave groove.

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