JP2018008303A - Welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method capable of easily removing weld flash.SOLUTION: An objective welding method includes: an overlapping process of forming a height-changing overlapping part J1 by overlapping the rear face of a second metallic member 10 in which the heights of surface and rear face change on the surface of a first metallic member 1 in which at least height of the surface changes; a friction stirring process of inserting a rotating rotary tool F for welding from the surface of the second metallic member 10, and carrying out friction stir welding by relative movement of the rotary tool F for welding to the height-changing overlapping part J1 in such a state as contacting a stirring pin F2 only with the second metallic member 10, or in such a state as contacting with both members 1 and 10; and a removal process of removing excess pieces in which the weld flash V is formed among the member 10 in a plasticized area W formed in the friction stirring process as a boundary.SELECTED DRAWING: Figure 3

Description

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

  For example, Patent Literature 1 discloses a joining method in which a first metal member and a second metal member are overlapped to form a superposed portion, and then a rotary tool is inserted from the surface of the second metal member to friction stir weld the superposed portion. Is described. In the friction stir welding, friction stirring is performed with only the stirring pin in contact with the first metal member and the second metal member.

JP2015-139800A

  In the conventional joining method, since the plastic fluidized metal is not pressed by the shoulder portion of the rotary tool, there is a problem that burrs are generated on the surface of the second metal member, and the process of removing the burrs becomes complicated. .

  Then, this invention makes it a subject to provide the joining method which can remove a burr | flash easily.

  In order to solve the above-mentioned problem, the present invention is a joining method for joining a first metal member and a second metal member using a rotary tool provided with a stirring pin, wherein at least the height of the surface changes. From the surface of the second metal member, a polymerization step of superposing the back surface of the second metal member on the surface of the first metal member and the back surface of the second metal member on which the height of the second metal member changes to form a superposed portion that changes in height. Inserting the rotating tool to rotate, the height changes in a state where only the stirring pin is in contact with the second metal member or in a state where both the first metal member and the second metal member are contacted A burr is formed in the second metal member at a boundary between a friction stir process in which the rotary tool is moved relative to the overlapping portion to perform friction stir welding and a plasticized region formed in the friction stir process. To remove the entire excess piece Characterized in that it comprises a step.

  According to such a joining method, it is possible to join the overlapping portions whose heights change, and to remove the surplus pieces where the burrs are formed, so that the burrs can be easily removed.

  Further, in the removing step, it is preferable to remove the surplus piece portion with a concave groove formed in the plasticized region as a boundary. According to this joining method, burrs can be removed more easily.

  In the friction stir step, it is preferable to set the joining conditions so that burrs generated in the friction stir welding are formed in the surplus pieces. According to such a joining method, since burrs can be concentrated on the surplus piece, the burrs can be more easily removed.

  In the friction stir step, it is preferable to set the joining conditions so that the surplus piece portion is removed from the second metal member simultaneously with the end of the friction stir welding. According to this joining method, the joining cycle can be shortened.

  According to the joining method according to the present invention, burrs can be easily removed.

It is a perspective view which shows the 1st metal member and 2nd metal member of the joining method which concern on 1st embodiment of this invention. It is sectional drawing which shows the superposition | polymerization process of the joining method which concerns on 1st embodiment. 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 sectional drawing which shows the removal process of the joining method which concerns on 1st embodiment. It is a perspective view which shows the removal process of the joining method which concerns on 1st embodiment. It is sectional drawing which shows the friction stirring process of the modification 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 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. In the joining method according to the present embodiment, a polymerization process, a friction stirring process, and a removal process are performed. In the following description, “front surface” means a surface opposite to the “back surface”.

  The polymerization step is a step of superposing the first metal member 1 and the second metal member 10 as shown in FIGS. Each of the first metal member 1 and the second metal member 10 is a metal member, and is formed of an equivalent material. The material of the first metal member 1 and the second metal member 10 is not particularly limited as long as it is a metal capable of friction stir. For example, aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, magnesium alloy, etc. Is appropriately selected.

  The 1st metal member 1 is comprised by the main-body part 2 which exhibits a rectangular parallelepiped, and the convex part 3 which is formed on the main-body part 2 and exhibits a cross-sectional trapezoid shape. The surface 3 a of the convex portion 3 is located above the surfaces 2 a and 2 b of the main body portion 2. The first surface 3 b of the convex portion 3 is inclined and connects the surface 2 a of the main body portion 2 and the surface 3 a of the convex portion 3. The second surface 3 c of the convex portion 3 is inclined and connects the surface 2 b of the main body portion 2 and the surface 3 a of the convex portion 3.

  The second metal member 10 is a plate-like member having a different height and formed with a constant plate thickness. The second metal member 10 includes base parts 11, 11, a central part 12, and inclined parts 13, 14. The central portion 12 is formed at a position higher than the base portions 11 and 11 in the center of the base portions 11 and 11. The inclined portion 13 connects one base portion 11 and the central portion 12 obliquely. The inclined portion 14 obliquely connects the other base portion 11 and the central portion 12. In addition, slits 5 and 5 are provided in the vicinity of the center of each end portion of the base portions 11 and 11.

  In the polymerization step, as shown in FIG. 2, the overlap portion J <b> 1 is formed by superimposing the back surface of the second metal member 10 on the surface of the first metal member 1. More specifically, the front surfaces 2a and 2b of the main body 2 and the back surfaces 11b and 11b of the base portions 11 and 11 are overlapped, and the front surface 3a of the convex portion 3 and the back surface 12b of the central portion 12 are overlapped. Further, the first surface 3b of the convex portion 3 and the back surface 13b of the inclined portion 13 are overlapped, and the second surface 3c of the convex portion 3 and the back surface 14b of the inclined portion 14 are overlapped.

  The first metal member 1 and the second metal member 10 are overlapped with almost no gap. The overlapping portion J1 is formed such that its height position changes. That is, in the overlapping portion J1, when the height (elevation) of the starting point (insertion position) of friction stirring is set as the reference height, there are sections having different reference heights and heights from the starting point to the end point. In the present embodiment, the overlapping portion J1 includes a first flat portion Ja, a first inclined portion Jb, a second flat portion Jc, a second inclined portion Jd, and a third flat portion Je.

  As shown in FIG. 3, the friction stirring step is a step of joining the overlapping portion J <b> 1 of the first metal member 1 and the second metal member 10 by friction stirring using the welding rotary tool F. The joining rotary tool F includes a connecting portion F1 and a stirring pin F2. The joining rotary tool F corresponds to a “rotary tool” in the claims. The joining rotary tool F is made of, for example, tool steel. The connecting part F1 is a part connected to a rotating shaft (not shown) of the friction stirrer. The connecting portion F1 has a cylindrical shape.

  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 is formed on the outer peripheral surface of the stirring pin F2. In the present embodiment, the spiral groove is formed in a counterclockwise direction from the proximal end toward the distal end in order to rotate the joining rotary tool F to the right.

  In addition, when rotating the rotation tool F for joining counterclockwise, it is preferable to form a spiral groove clockwise as it goes to a front-end | tip from a base end. By setting the spiral groove in this way, the metal plastically fluidized during friction stirring is guided to the tip side of the stirring pin F2 by the spiral groove. Thereby, the quantity of the metal which overflows outside the to-be-joined metal member (the 1st metal member 1 and the 2nd metal member 10) can be decreased.

  The joining rotary tool F may be attached to a friction stirrer such as a machining center, but may be attached to, for example, an arm robot having a rotating means such as a spindle unit at the tip. By attaching the welding rotary tool F to the arm robot, the rotation center axis C of the welding rotary tool F can be easily inclined.

  In the friction stirring step, the stirring pin F2 of the welding rotary tool F rotated to the right is inserted into the start position Sp set on the surface of the second metal member 10, and the welding rotary tool F is relatively moved along the overlapping portion J1. Move. In the present embodiment, the friction stirring is performed in a state where the rotation center axis of the welding rotary tool F is always parallel to the vertical axis. The first metal member 1 and the second metal member 10 are joined by friction stir around the stirring pin F2 by the friction stirring step. A plasticized region W is formed in the movement locus of the welding rotary tool F.

  As shown in FIG. 4, in the joining step according to the present embodiment, only the stirring pin F <b> 2 is attached to the first metal member 1 and the second metal member 10 while keeping the insertion depth of the stirring pin F <b> 2 into the overlapping portion J <b> 1 substantially constant. Friction stirring is performed in the state of contact with In the friction agitation process according to the present embodiment, friction agitation is performed by moving the joining rotary tool F up and down with respect to a gantry (not shown) to which the first metal member 1 and the second metal member 10 are fixed.

  Accordingly, the depth Za of the plasticized region W of the first flat portion Ja, the depth Zb of the plasticized region W of the first inclined portion Jb (the depth of the plasticized region W on the line orthogonal to the surface 13a of the inclined portion 13). And the depth Zc of the plasticized region W of the second flat portion Jc can be made substantially equal. The “insertion depth” of the stirring pin F2 means a distance from the surface of the second metal member 10 on the rotation center axis C of the welding rotary tool F to the tip of the stirring pin F2.

  In the joining process according to the present embodiment, the joining rotary tool F is moved up and down with respect to the gantry (not shown), but the height position of the joining rotator F is fixed and the gantry is moved up and down. Friction stirring may be performed. In the present embodiment, the friction stir welding is performed in a state where only the stirring pin F2 is in contact with the first metal member 1 and the second metal member 10, but only the stirring pin F2 is in contact with only the second metal member 10. Friction stir welding may be performed in the state of being made. In this case, the overlapping portion J1 is plastically fluidized by the frictional heat between the second metal member 10 and the stirring pin F2.

  As shown in FIG. 5, in this embodiment, the shear side (advancing side: the side where the moving speed of the rotating tool is added to the tangential speed on the outer periphery of the rotating tool) is the left side in the traveling direction. In addition, the moving direction and the rotation direction of the joining rotary tool F are set. The rotation direction and the traveling direction of the joining rotary tool F are not limited to those described above, and may be set as appropriate.

  For example, when the rotational speed of the welding rotary tool F is low, the shear side is larger than the flow side (retreating side: the side where the moving speed of the rotary tool is subtracted from the tangential speed on the outer periphery of the rotary tool). In this case, the temperature of the plastic fluidized material is likely to rise, so that a groove is formed on the shear side in the plasticized region W, and a large number of burrs V tend to be generated on the shear side outside the plasticized region W. On the other hand, for example, when the rotational speed of the rotating tool F for joining is high, the temperature of the plastic fluidized material increases on the shear side, but a concave groove is generated on the flow side in the plasticizing region W due to the higher rotational speed. However, many burrs V tend to be generated on the flow side outside the plasticized region W.

  In the present embodiment, since the rotation speed of the joining rotary tool F is set high, a concave groove D is generated on the flow side in the plasticizing region W as shown in FIG. There is a tendency that many burrs V are generated on the flow side. The symbol X in FIG. 5 is the junction center line. The concave groove D is a portion of the plasticized region W that is deeper. Moreover, the moving speed (feeding speed) of the joining rotary tool F can be increased by setting the rotational speed of the joining rotary tool F faster. Thereby, a joining cycle can be shortened.

  In the friction stirring step, which side of the traveling direction of the welding rotary tool F the burr V is generated differs depending on the joining conditions. The joining conditions include the rotational speed, rotational direction, moving speed (feed speed) of the rotating tool F for joining, the inclination angle (taper angle) of the stirring pin F2, the material of the first metal member 1 and the second metal member 10, It is determined by each element such as thickness and the combination of these elements. If the side where the burr V is generated or the side where a lot of burr V is generated is set to the surplus piece portion 20 side which will be described later, depending on the joining conditions, the concave groove D formed in the plasticized region W is also a surplus piece. Since it tends to be formed on the portion 20 side, it is preferable because a removal step described later can be easily performed.

  As shown in FIGS. 5 and 6, the removal step is a step of cutting off the surplus piece 20 that is a part of the second metal member 10. The surplus piece portion 20 is a portion of the second metal member 10 that is cut off with the plasticized region W as a boundary. In the present embodiment, the portion on the outer side (the right side in the traveling direction of the joining rotary tool F) than the concave groove D formed in the second metal member 10 is the surplus piece portion 20.

  In the removing step, the slits 5 and 5 are removed from each other by bending while turning up the end portion of the surplus piece 20 starting from one of the slits 5 and 5. In the removing step, the surplus piece portion 20 may be bent using an apparatus, but in the present embodiment, it is bent and cut manually.

  According to the joining method described above, the overlapping portion J1 whose height changes can be joined, and since the surplus piece portion 20 on which the burr V is formed is removed, the burr V can be easily removed. . In the friction stirring step, the joining conditions are set so that burrs V are formed on the surplus piece 20 side. Thereby, since the burr | flash V can be concentrated on the surplus piece part 20, the burr | flash V can be removed more easily.

  Further, as in the present embodiment, friction stirring is performed in a state where only the stirring pin F2 is in contact with the first metal member 1 and the second metal member 10, or in a state where only the stirring pin F2 is in contact with the second metal member 10. By performing the above, it is possible to friction stir weld the overlapping portion J1 in a deep position without applying a large load to the friction stirrer. Further, by making the plasticized region W constant, the bonding strength can be made constant.

  Moreover, as shown in FIG. 5, according to this embodiment, the ditch | groove D is formed in the plasticization area | region W and the flow side. Moreover, since the burr | flash V is formed in the flow side outside the plasticization area | region W, the burr | flash V can be efficiently excised with the surplus piece part 20. FIG. Thereby, since a joined part (plasticization region W) can be largely left, joining strength can be increased. Further, the surplus piece portion 20 can be easily bent by the concave groove D, and the joined portion (plasticized region W) can be finished finely without performing a burr removing operation separately.

  In the friction stir process, the joining conditions may be set so that the surplus piece 20 is removed from the second metal member 10 simultaneously with the end of the friction stir welding. That is, in the friction stirring step, the joining condition may be set so that the concave groove D is formed deeper and the surplus piece 20 is detached from the second metal member 10 simultaneously with the end of the friction stirring joining. . Thereby, a joining cycle can be shortened. In this case, while providing a pair of tab members having the same thickness as the main body 2 of the first metal member 1 at both ends of the first metal member 1, the start position and the end position of friction stirring are set on the tab member. It is preferable to perform frictional stirring over the entire length of the second metal member 10.

[Modification]
FIG. 7 is a cross-sectional view showing a friction stirring step of a modification of the joining method according to the first embodiment. As shown in FIG. 7, in the modified example, when performing the friction stirring step, the friction stirring is performed while inserting the welding rotary tool F perpendicularly to the joining surface. In the friction stirring step of the modified example, in the first flat portion Ja, the second flat portion Jc, and the third flat portion Je, the rotation center axis C of the welding rotary tool F is parallel to the vertical axis, as in the first embodiment. Friction stir is performed in the state. On the other hand, in the 1st inclination part Jb and the 2nd inclination part Jd, the rotation tool F for joining is made to incline with respect to a vertical axis, and it is for joining with respect to the joining surface of the 1st inclination part Jb and the 2nd inclination part Jd. Friction stirring is performed with the rotation center axis of the rotary tool F being vertical.

  In the case of performing the modification, for example, it is preferable to perform the friction stirring by attaching the joining rotary tool F to a robot arm having a driving unit such as a spindle unit at the tip. According to such a friction stirrer, the angle of the rotation center axis C of the joining rotary tool F can be easily changed. Thereby, even when the height of the overlapping portion J1 changes, the angle of the rotation center axis C of the rotation tool F for bonding with respect to the vertical axis is changed during friction stirring, so that the rotation tool for bonding with respect to the bonding surface. Friction stirring can be carried out continuously with F being always vertical.

  Even in the modification described above, it is possible to achieve substantially the same effect as that of the first embodiment. Moreover, since the joining rotary tool F can be inserted perpendicularly to each joining surface, even with an inclined surface, friction stirring can be performed up to a deep position of the overlapping portion J1.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the joining method according to the second embodiment, a polymerization process, a friction stirring process, and a removal process are performed. The second embodiment is different from the first embodiment in that the metal members are curved.

  As shown in FIG. 8, in the polymerization step, the first metal member 30 and the second metal member 40 are overlapped. The first metal member 30 and the second metal member 40 are formed of a metal that can be frictionally stirred and curved with an equivalent radius of curvature. By overlapping the front surface 30a of the first metal member 30 and the back surface 40b of the second metal member 40, the overlapping portion J2 is formed. The overlapped first metal member 30 and second metal member 40 are clamped to the gantry K by a jig.

  The friction stirring step is a step of performing friction stir welding of the overlapping portion J2 using the welding rotary tool F. In the friction stirring step, the stirring pin F2 of the joining rotary tool F is inserted from the surface 40a of the second metal member 40, and the joining rotary tool F is relatively moved along the overlapping portion J2. In the friction stirring step, the inclination angle of the joining rotary tool F is gradually changed so that the rotation center axis C of the joining rotary tool F overlaps the normal line of the second metal member 40. In the friction stirring step, the insertion depth of the stirring pin F2 is set so that the plasticized region W1 is constant. Since the removal process is the same as that of the first embodiment, description thereof is omitted.

  Also in the friction stir welding according to the second embodiment described above, an effect substantially equivalent to that of the first embodiment can be obtained. Moreover, even if it is a case where the superposition | polymerization part J2 is curving like the 1st metal member 30 and the 2nd metal member 40, this invention is applicable.

  Although the embodiments and modifications of the present invention have been described above, design changes can be made as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 1st metal member 2 2nd metal member F Joining rotary tool (rotary tool)
F1 connecting portion F2 stirring pin C rotation center axis J1 overlapping portion V burr W plasticizing region

Claims (4)

A joining method for joining the first metal member and the second metal member using a rotary tool equipped with a stirring pin,
A polymerization step of superposing a back surface of the second metal member, the height of the front surface and the back surface of which changes at least on the surface of the first metal member, the height of the surface of which changes, and forming a polymerization portion where the height changes; ,
The rotating tool rotating from the surface of the second metal member is inserted, and only the stirring pin is brought into contact with the second metal member, or both the first metal member and the second metal member are brought into contact with each other. A friction stir process in which friction stir welding is performed by relatively moving the rotary tool with respect to the overlapping portion where the height changes.
And a removing step of removing the surplus piece portion in which the burr is formed in the second metal member, with the plasticized region formed in the friction stirring step as a boundary.   2. The joining method according to claim 1, wherein in the removing step, the surplus piece portion is removed with a concave groove formed in the plasticized region as a boundary.   The joining method according to claim 1 or 2, wherein in the friction stirring step, joining conditions are set so that burrs generated in the friction stir welding are formed in the surplus piece.   4. The welding condition according to claim 1, wherein in the friction stirring step, a joining condition is set so that the surplus piece is removed from the second metal member simultaneously with the end of the friction stir welding. The joining method according to item.

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