JP5509798B2 - Joining method - Google Patents

Description

  The present invention relates to a joining method combining friction stir welding and welding.

  In recent years, friction stir welding has been developed and put to practical use as a new joining method that replaces welding and brazing as a joining method for metallic members to be joined. Friction stir welding is solid-phase bonding, and the members to be bonded can be bonded at a lower temperature than welding (melting bonding) or brazing (liquid-solid reaction bonding). There is an advantage that there is little bonding failure due to (for example, see Patent Document 1).

JP 2006-312198 A

  Friction stir welding is performed by applying a large tool load to a member to be joined from a welding tool called a tool. Due to this, the friction stir welding can join the butt portion of the member to be joined having a complicated shape such as a curved surface shape or a square shape (a simple corner portion or a step portion where the corner portions are continuously connected). It has the problem of being difficult.

  In addition, in friction stir welding, a portion where the joining strength cannot be sufficiently obtained at a joining end portion (a portion where stirring is insufficient because a projection called a probe provided on the joining tool does not pass) occurs.

  Further, the friction stir welding has a problem that a hole is formed in a joint portion by a probe of a welding tool.

  Therefore, the present invention proposes a joining method that can make use of the advantages of friction stir welding and compensate for the disadvantages.

In order to solve the above-described problems, a joining method according to the present invention includes a joining step in which a plurality of metal members to be joined are brought into contact to form a joining portion, and friction stirring in which friction stirring is performed along a part of the joining portion. A welding step for performing welding along the other part of the butt portion, and the welding step is performed after the friction stir welding step, and a welding end is formed by the friction stir welding step. The joining end in the friction stir welding process is a non-passing region of the probe in the friction stir welding process .

  ADVANTAGE OF THE INVENTION According to this invention, the joining method which can compensate the fault can be provided, utilizing the advantage of friction stir welding.

The flowchart which showed the joining method which concerns on embodiment of this invention. Schematic which showed the friction stir welding process among the joining methods which concern on embodiment of this invention. The figure which showed the joining tool used for the joining method which concerns on embodiment of this invention. Schematic which showed an example of the structure joined by the joining method which concerns on embodiment of this invention. Schematic which showed an example of the structure joined by the joining method which concerns on embodiment of this invention. The figure which showed an example of the joining strength of the structure joined by the joining method which concerns on embodiment of this invention. The schematic sectional drawing which showed the other example of the structure joined by the joining method which concerns on embodiment of this invention. The perspective view which showed the other example of the structure joined by the joining method which concerns on embodiment of this invention. The perspective view which showed the other example of the structure joined by the joining method which concerns on embodiment of this invention. The figure which showed the mode of the strength test of the structure joined by the joining method which concerns on embodiment of this invention. The figure which showed the other example of the joint strength of the structure joined by the joining method which concerns on embodiment of this invention.

  Hereinafter, an embodiment of a bonding method according to the present invention will be described with reference to FIGS. 1 to 11.

  FIG. 1 is a flowchart illustrating a bonding method according to an embodiment of the present invention.

  As shown in FIG. 1, the joining method according to the present embodiment includes a butting process S1, a friction stir welding process S2 that is performed after the butting process S1, and a welding process S3 that is performed at least after the butting process S1. . In addition, the welding method which concerns on this embodiment performs welding process S3 after friction stir welding process S2.

  The butting step S1 is a step of forming a butting portion on a plurality of members to be joined that are joined by the joining method according to this embodiment. The member to be joined is a metal member including, for example, an aluminum alloy and may be any member that can be joined by friction stir welding and welding. The abutting portion includes an abutting surface (or a “joining surface”) that abuts the surfaces formed on the respective members to be joined, and is a region joined in the friction stir welding step S2 and the welding step S3.

  The friction stir welding step S2 is a step of moving the welding tool along a part of the abutting portion and performing the main joining of the members to be joined by friction stirring.

  The welding step S3 is a step in which the heat source is moved along the other part of the abutting portion and main joining of the members to be joined is performed by welding. The welding method performed in the welding step S3 includes arc welding using an arc as a heat source (including gas shield arc welding including TIG welding and MIG welding, self-shielded arc welding, etc.), gas welding, laser welding, electron beam welding, and the like. Known welding methods can be used.

  Next, the friction stir welding step S2 will be described in detail.

  FIG. 2 is a schematic view showing a friction stir welding step in the joining method according to the embodiment of the present invention.

  As shown in FIG. 2, the friction stir welding step S <b> 2 is a step of joining a part of the abutting portion where a pair of joined plates 11, 12 which are a plurality of joined members are abutted using the joining tool 14.

  The joining tool 14 includes, for example, a columnar rotating body 15 coupled to a driving unit of a rotation driving device (not shown), a columnar probe 16 integrally formed by protruding from the tip of the rotating body 15, Is provided. The end face of the rotating body 15 is called a shoulder 17. The probe 16 protrudes from the end face of the rotating body 15 to a length corresponding to the thickness of the abutting portion of the joined plates 11 and 12. In addition, the probe 16 is provided with a thread groove or the cross-sectional shape in the direction orthogonal to the rotation axis is formed in a non-circular shape (for example, an ellipse or a drum shape) in order to efficiently stir the joined plates 11 and 12. Or

  In the friction stir welding step S2, the welding tool 14 and the plate to be joined 11 are pressed against the abutting portions of the plates to be joined 11 and 12 while rotating the welding tool 14 at a high speed (solid arrow R in FIG. 2) by the rotation drive device. , 12 is used to soften the joint portions of the plates 11 and 12 to be joined, and the softened portions are agitated by the rotation of the joining tool 14 to join the plates 11 and 12 to be joined. After the joined portions of the plates 11 and 12 that have been softened by the frictional heat are stirred so as to wrap around the joining direction of the joining tool 14 (solid arrow F in FIG. 2), friction occurs as the joining tool 14 moves. The plates to be joined 11 and 12 are joined by rapidly losing heat and cooling and hardening.

  FIG. 3 is a view showing a joining tool used in the joining method according to the embodiment of the present invention.

  As shown in FIG. 3, the normal direction of the surface 21 of the members to be joined (here, the plates 11 and 12 to be joined) and the joining direction (solid arrow in FIG. 3) that is the traveling direction of the joining tool 14 are used as a reference. Then, the joining tool 14 has its free end side (lower end side having the probe 16) advanced in the joining direction (solid arrow F in FIG. 3), and the rotation axis of the joining tool 14 and the normal direction of the surface 21 The advance angle θ is made between In the friction stir welding step S2, bonding is possible even if the advance angle θ is 0 °, but since a joining defect is likely to occur, the advance angle θ is generally set to about 2 ° to 5 °.

  Here, in the friction stir welding, due to the structure of the welding tool 14, regions where the probe 16 does not pass are formed at the start and end portions of the joining portion, and thus the members to be joined in this region cannot be sufficiently stirred. In addition, in the friction stir welding, a hole that accompanies the withdrawal of the probe 16 is formed at the end portion of the joint portion. Such insufficient stirring at both joint ends and the presence of a pull-out hole at the terminal end may reduce the joint strength.

  Therefore, the joining method according to the present embodiment performs welding by adjoining or overlapping the joining end portion of the friction stir welding step S2, thereby improving the joining quality.

  4 and 5 are schematic views showing an example of a structure joined by the joining method according to the embodiment of the present invention.

  As shown in FIGS. 4 and 5, the joining plate members 22 and 22A are structures in which the plates to be joined 11 and 12 are joined by the joining method according to the embodiment of the present invention.

  Specifically, as shown in FIG. 4, the joining plate material 22 is joined with the friction stir welding portion 24 in the friction stir welding step S2 and the weld joint portion 25 in the welding step S3 adjacent to each other.

  On the other hand, as shown in FIG. 5, the joining plate material 22A is subjected to the welding step S3 after the friction stir welding step S2, and the friction stir welding portion 24 by the friction stir welding step S2 and the weld joint portion 25 by the welding step S3 are overlapped. They are joined together. This overlapped portion is called an overlap portion 26.

  The overlap portion 26 is formed by superimposing the end portion 25b of the weld joint portion 25 in the welding step S3 on the start end portion 24a of the friction stir joint portion 24 in the friction stir joint step S2. The overlap portion 26 may be formed at either the start end portion 24a or the end portion 24b of the friction stir welding portion 24 in the friction stir welding step S2, and the start end portion 25a or the end end of the weld joint portion 25 in the welding step S3. Any of the portions 25b may be overlapped.

  At this time, the range of the overlap portion 26 is preferably equal to or greater than the sum of the radius of the shoulder 17 and the radius of the probe 16 of the welding tool 14 used in the friction stir welding step S2. Thus, by overlapping the friction stir welding portion 24 and the weld joint portion 25 in both steps, the region where the probe 16 does not pass in the friction stir welding step S2 (particularly, the start end portion 24a and the end portion 24b of the friction stir welding portion 24). ) Can be joined by welding in the welding step S3.

  The joining plate materials 22 and 22A will be further described in detail.

  The joining plate materials 22 and 22A are structures in which the plates to be joined 11 and 12 which are plate materials having a thickness of 4 mm made of an aluminum alloy are joined by the joining method according to the present embodiment.

  The welding tool 14 used in the friction stir welding step S2 has a shape in which the shoulder 17 has a diameter of about 12 mm, the probe 16 has a diameter of about 5 mm, and the probe 16 has a protruding length of about 3.5 mm. The joining conditions of the friction stir welding step S2 are: the rotational speed of the joining tool 14 is about 1500 rpm, the joining speed of the joining tool 14 is about 300 mm / min, the advance angle of the joining tool 14 is about 3 °, and the insertion amount of the probe 16 to the member to be joined is about. 3.7 mm, a waiting time of about 2 seconds from when the joining tool 14 is inserted into the member to be joined to when the joining tool 14 starts to move, and after the movement of the joining tool 14 is completed, the joining tool 14 is removed from the member to be joined. The waiting time until drawing was about 1 second.

  The welding conditions in the welding step S3 were such that a welding rod for aluminum (JIS Z 3232: A5356BY) was used as the filler material, the current value was about 130 A to 170 A, and the joining speed was about 100 mm / min.

  Further, in the joining plate material 22A, the joining end portion in the friction stir welding step S2 and the joining end portion in the welding step S3 were overlapped by about 20 mm. This is about 1.6 times the diameter of the shoulder 17 of the welding tool 14.

  Here, the strength of the joined portions of the joining plate materials 22 and 22A will be described.

  The test piece of the joining plate material 22 cut out a region (a region T1 sandwiched between two-dot chain lines in FIG. 4) including a joining end portion (here, a start end portion 24a) in a friction stir welding portion 24 by friction stir welding. Is.

  On the other hand, the test piece of the joining plate material 22A is obtained by cutting out a region including the overlap portion 26 (region T2 sandwiched between two-dot chain lines in FIG. 5) in the friction stir welding portion 24 by friction stir welding.

  Both test pieces have a width that is approximately twice the length of the overlap portion 26 in the joining direction. Moreover, the bonding strength to be evaluated is the tensile strength with respect to the normal direction of the abutting surface.

  FIG. 6 is a view showing an example of the bonding strength of the structures bonded by the bonding method according to the embodiment of the present invention.

  As shown in FIG. 6, the bonding plate material 22 </ b> A was improved in bonding strength by about 2.5 times compared to the bonding plate material 22.

  The test piece of the joining plate material 22 has only the friction stir welding portion 24 joined by the friction stir welding step S2. The friction stir welding portion 24 is hardly affected by heat in the welding step S3. That is, the test piece of the joining plate material 22 remains in a region where the probe 16 does not pass in the friction stir welding step S2 (here, the start end portion 24a of the friction stir welding portion 24) without being welded. Therefore, it is considered that the test piece of the bonding plate material 22 has substantially the same bonding strength as the bonded portion bonded only by the friction stir welding.

  On the other hand, the test piece of the joining plate material 22 </ b> A includes an overlap portion 26. That is, the test piece of the joining plate material 22A is welded and joined to a region where the probe 16 does not pass in the friction stir welding step S2 (here, the start end portion 24a of the friction stir welding portion 24).

  Next, the case where the to-be-joined member which has a non-planar shape part is joined by the joining method which concerns on this embodiment is demonstrated.

  FIG. 7 is a schematic cross-sectional view showing another example of a structure joined by the joining method according to the embodiment of the present invention.

  As shown in FIG. 7, the joining pipe 35 is a structure in which rounded round tube materials 27 and 28 that are joined members are joined by the joining method according to the embodiment of the present invention.

  The rounded round tube materials 27 and 28 have a substantially rectangular cross-sectional shape in the direction perpendicular to the longitudinal axis, and have a side portion 31 having a substantially planar surface and a rounded corner portion 32 having a rounded surface. It is a hollow tube.

  The joining pipe 35 joins the rounded corner portion 32 in the welding step S3 after joining the side portion 31 in the friction stir welding step S2, and welds the friction stir welding portion 24 in the friction stir welding step S2 and the weld joint portion in the welding step S3. 25 and are joined together.

  That is, the joining pipe 35 has the overlap part 26 comprised by overlapping the welding joining part 25 by welding process S3 on the friction stirring joining part 24 by friction stirring joining process S2 similarly to the joining board | plate material 22A.

  The overlap portion 26 is formed continuously from the rounded corner portion 32 and positioned on the side portion 31 joined by friction stir welding.

  8 and 9 are perspective views showing other examples of structures joined by the joining method according to the embodiment of the present invention.

  As shown in FIGS. 8 and 9, the joining pipes 37 and 37 </ b> A are structures in which the joined pipe materials 41 and 42 are joined by the joining method according to the embodiment of the present invention.

  The to-be-joined pipe materials 41 and 42 are hollow tubes each having a substantially rectangular cross-sectional shape in the direction perpendicular to the longitudinal axis, and having two adjacent rounded corner portions 45 and two adjacent substantially perpendicular corner portions 46. is there.

  As shown in FIG. 8, the joining pipe 37 is joined by adjoining the friction stir welding portion 24 in the friction stir welding step S2 and the weld joint portion 25 in the welding step S3.

  The side portion 47 having a substantially planar surface located between the two rounded corner portions 45 is the friction stir welding portion 24 by the friction stir welding step S2.

  On the other hand, as shown in FIG. 9, the joining pipe 37A performs the welding step S3 after the friction stir welding step S2, and overlaps the friction stir welding portion 24 by the friction stir welding step S2 and the weld joint portion 25 by the welding step S3. They are joined together.

  The overlap portion 26 is configured by superimposing the welded joint portion 25 of the welding step S3 on the start end portion 24a and the end portion 24b of the friction stir welded portion 24 of the friction stir welding step S2.

  The joining pipes 37 and 37A will be further described in detail.

  The joining pipes 37 and 37A are, for example, body frames of motorcycles. The joining pipes 37 and 37A are structures in which joined pipe materials 41 and 42 which are hollow pipes having a plate thickness of 4 mm made of aluminum alloy (JIS H 4100: 6N01-T5) are joined by the joining method according to the present embodiment. It is. The to-be-joined pipe materials 41 and 42 have a substantially rectangular cross section having a long side of about 55 mm and a short side of about 50 mm in a cross-sectional view perpendicular to the axis.

  The welding tool 14 used in the friction stir welding step S2 has a shape in which the diameter of the shoulder 17 is about 8 mm, the diameter of the probe 16 is about 3 mm, and the protruding length of the probe 16 is about 1.5 mm. The joining conditions of the friction stir welding step S2 are: the rotational speed of the joining tool 14 is about 1500 rpm, the joining speed of the joining tool 14 is about 100 mm / min, the advance angle of the joining tool 14 is about 3 °, and the insertion amount of the probe 16 with respect to the member to be joined is about 1.7 mm, waiting time of about 4 seconds from when the joining tool 14 is inserted into the member to be joined until the movement of the joining tool 14 is started, and after the movement of the joining tool 14 is finished, the joining tool 14 is removed from the member to be joined. The waiting time until drawing was about 1 second.

  The welding conditions in the welding step S3 were such that a welding rod for aluminum (JIS Z 3232: A5356BY) was used as the filler material, the current value was about 130 A to 170 A, and the joining speed was about 100 mm / min.

  Moreover, the joining pipe 37A overlapped the joining end part by friction stirring joining process S2 and the joining end part by welding process S3 about 12 mm. This is about 1.5 times the diameter of the shoulder 17 of the welding tool 14.

  Next, the strength of the joint portion of the joint pipes 37 and 37A will be described.

  FIG. 10 is a view showing a state of a strength test of a structure joined by the joining method according to the embodiment of the present invention.

  As shown in FIG. 10, a three-point bending test was performed in order to evaluate the joint strength of the joint pipes 37 and 37A. The joint strength to be evaluated is the bending strength at the time of breaking or buckling in the three-point bending test for the joint pipes 37 and 37A.

  In addition, the load in the three-point bending test was applied in a direction in which a tensile force is generated in the friction stir welding portion 24 in the friction stir welding step S2.

  FIG. 11 is a diagram illustrating another example of the bonding strength of the structures bonded by the bonding method according to the embodiment of the present invention.

  As shown in FIG. 11, the joining tube 37 </ b> A was improved in joining strength by about twice as compared with the joining tube 37.

  In addition, the bending strength of the joining pipe 37 is a bending strength at the time of fracture | rupture in a junction part. On the other hand, the joining pipe 37A has a bending strength when the base material undergoes buckling deformation.

  The joining pipe 37 has only the friction stir welding portion 24 joined in the friction stir welding step S2 (does not have the overlap portion 26). The friction stir welding portion 24 is hardly affected by heat in the welding step S3. That is, in the joining pipe 37, the region where the probe 16 does not pass in the friction stir welding step S2 (here, the start end portion 24a of the friction stir welding portion 24) remains unwelded.

  On the other hand, the joining pipe 37 </ b> A includes the overlap portion 26. That is, the joining pipe 37A is welded and joined in a region where the probe 16 does not pass in the friction stir welding step S2 (here, the start end portion 24a of the friction stir welding portion 24).

  Therefore, according to the joining method according to the present embodiment, when joining a member to be joined having a gap (for example, about 0.5 mm or more) or a step (for example, about 0.5 mm or more) on the abutting surface, A gap or a step can be joined by welding, and other portions can be joined by friction stir welding. According to the joining method according to the present embodiment, it is possible to reliably join a gap portion or a step portion that is difficult to join by friction stir welding and obtain a high joining strength.

  In addition, according to the joining method according to the present embodiment, for example, a member to be joined having a thick portion having many gas defects that are difficult to join by welding, or stress that does not provide sufficient joining strength by joining by welding. These parts can be joined to the member to be joined having the concentrated portion by friction stir welding, and the joining strength can be improved.

  Furthermore, according to the joining method according to the present embodiment, in addition to a gap (for example, about 0.5 mm or more) or a step (for example, about 0.5 mm or more) on the abutting surface, a portion having a curved surface shape and a square shape ( When joining a member to be joined having a complicated shape portion (hereinafter referred to as “non-planar shape portion”) such as a mere corner portion or a portion having a step portion where corner portions are continuously connected) The portion (the portion corresponding to the rounded corner portion 32 in the joining tube 35) can be joined by welding, and the other substantially planar portion (the portion corresponding to the side portion 31 in the joining tube 35) can be joined by friction stir welding. . When joining the members to be joined having a non-planar shape portion only by friction stir welding, it is difficult to join the non-planar shape portion (the portion corresponding to the rounded corner portion 32 in the joining tube 35), and the joining strength may be reduced. However, according to the joining method according to the present embodiment, a non-planar shape portion (a portion corresponding to the rounded corner portion 32 in the joining tube 35) can be reliably joined to obtain a high joining strength.

  Furthermore, according to the joining method according to the present embodiment, the overlap portion 26 can reliably join the region through which the probe 16 does not pass by welding, and the strength of the joined portion can be dramatically improved.

  Moreover, according to the joining method according to the present embodiment, the overlap portion 26 can reliably fill the extraction hole of the probe 16 in the friction stir welding in the welding step S3. At this time, since the burrs of the friction stir welding portion 24 formed in the friction stir welding can be removed by melting in the welding step S3, the appearance quality of the overlap portion 26 can be improved.

  Note that the structures to be joined by the joining method according to the embodiment are not limited to the joining plate materials 22 and 22A, the joining pipe 35, and the joining pipes 37 and 37A, but are hollow extruded materials having a non-planar shape portion, square pipe materials, and various types. The present invention can also be applied to back-joining members to be joined such as frame materials, press-formed products, cast products, forged products, and sintered products.

  Therefore, according to the joining method according to the present invention, the disadvantages can be compensated while taking advantage of the friction stir welding.

DESCRIPTION OF SYMBOLS 11, 12 Plate to be joined 14 Joining tool 15 Rotating body 16 Probe 17 Shoulder 21 Surface 22, 22A Joining plate material 24 Friction stir welding part 24a Starting end part 24b Ending part 25 Welding joining part 25b Ending part 25a Starting end part 26 Overlap part 27, 28 Rounded corner tube material 31 Side portion 32 Rounded corner portion 35 Bonded tube 37, 37A Bonded tube 41, 42 Pipe to be joined 45 Rounded portion 46 Corner portion 47 Side portion

Claims (7)

A butting step of butting a plurality of metal members to be joined to form a butting portion;
A friction stir welding step of performing friction stir along a part of the abutting portion;
A welding step of performing welding along the other part of the abutting part,
The welding step is performed after the friction stir welding step, and joining ends by the friction stir welding step are joined by the welding step ,
The joining method according to claim 1, wherein the joining end in the friction stir welding process is a non-passing region of the probe in the friction stir welding process . The joining method according to claim 1, wherein the friction stir welding step joins a substantially planar portion of the abutting portion. The joining method according to claim 1, wherein the welding step joins a non-planar shape portion of the abutting portion. The joining method according to any one of claims 1 to 3, wherein a joining end by the friction stir welding step and a joining end by the welding step are overlapped. The joining method according to claim 4, wherein a portion where the joining end by the friction stir welding step and the joining end by the welding step overlap is located at a substantially planar portion of the abutting portion. The range in which the joint end by the friction stir welding process overlaps the joint end by the welding process is equal to or greater than the sum of the shoulder radius and the probe radius of the welding tool used in the friction stir welding process. Or the joining method of 5. The joining method according to any one of claims 1 to 6, wherein a joining end by the welding step is overlapped with a joining end by the friction stir welding step.

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