JP2001071156A - Joining member, and its frictional agitation joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member having a joined part which is free from any nonplastic flow even with a step, beautiful in the joined surface and excellent in strength. SOLUTION: In a joined member 5 with butted parts 12 of joining members different in thickness joined through the frictional agitation joining, a stepped part of the butted part 12 on the opposite side which is frictional agitation joined is cladded by welding. A first joining member 1 is butted to a second joining member 2 thicker than the first joining member 1, and a backing plate 3 having a stepped part as high as a step 13 of the butted part 12 on the opposite side to the surface to be frictional agitation joined is disposed to form a gap 14 between the butted part 12 and the backing plate 3, a probe 11 is pressed into the butted part 12 from the side for frictional agitation joining while rotating the probe 11, and the plastic flow is implemented by moving the probe along the butted part 12, and the first and second joining members are joined with each other while filling a material in the gap 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining member made of a metal or an alloy and obtained by abutting joining materials having different plate thicknesses and joining them by friction stir welding, and a friction stir welding method (FSW) therefor.

[0002]

2. Description of the Related Art Conventionally, in a friction stir welding method for joining members having different thicknesses, two joining materials having different thicknesses are butt-joined, and a probe is inserted while rotating the probe from the side where a step is present at the abutting portion. This is performed by bringing the probe into contact with the surface of the thick joining material and moving the probe with respect to the joining material along the abutting portion.

In this friction stir welding method, since the probe is inserted from the side where the step is present, the length of the probe is limited, so that the probe does not easily come into contact with the surface of a thin joining material, and Sufficient frictional heat cannot be generated, and joint defects are likely to occur. Also, if the probe is pressed strongly to make the probe contact the surface of the thin joining material, the surface of the thick joining material is shaved and the amount of heat generated increases, the temperature of the joint increases, and the vicinity of the butted portion Has a negative thermal effect and burrs are likely to occur.

[0004] Friction stir welding can also be performed by placing a backing plate on the back surface of the thin joining material to make the surface on the probe insertion side uniform, and in this case, root cracks occur on the back surface of the butted portion. There is a problem that it is easy to do. Also,
If the probe is sufficiently inserted, the tip of the probe easily comes into contact with the backing plate, and the probe or the backing plate may be damaged. Further, a bonding defect may occur on the back surface of the bonding portion, or the bonding material and the backing plate may be bonded.

Various joining methods have been proposed to solve some of the above-mentioned problems (JP-A-10-193143, JP-A-10-249553, JP-A-11-5).
179).

Japanese Patent Application Laid-Open No. Hei 10-193143 discloses that two joining materials are abutted so that a step is formed on the surface, and a contact member having a thickness corresponding to the step is overlapped on the surface of the thin joining material on the probe insertion side. In addition, a friction stir welding method in which the step is eliminated and the two joining materials are butt joined by a probe in this state is disclosed.

Japanese Patent Application Laid-Open No. Hei 10-249553 discloses a method in which two joining materials are butted so that a step is formed on the surface, and a probe is made thin at an inclination angle of 10 ° or less with respect to the abutting portion. A friction stir welding method for performing butt welding in a state of being inclined toward a joining material is disclosed.

[0008] Further, JP-A-11-5179 discloses that
A pair of processing members are arranged on a backing plate provided with a groove so that the joints thereof are aligned with the grooves, and while rotating a tool having a probe formed at the tip, the joints of the processing members are formed. A friction stir welding method for joining working members by utilizing the plastic fluidity of metal by rotating a tool and moving the tool along a joint while rotating the tool is disclosed. In this conventional friction stir welding method, since a groove is formed in the backing plate at a position corresponding to the joint to insert the probe, the tip of the probe does not contact the backing plate, and Some problems are solved.

[0009]

However, Japanese Patent Application Laid-Open No.
According to the friction stir welding method described in Japanese Patent No. 193143, when joining two joining materials having different plate thicknesses, a contact plate is overlapped on a thin joining material, and the contact plate and the thick joining material are joined together. It is necessary to insert a probe into the boundary of the two and join both joining materials. In addition, it is necessary to adhere a backing plate to the thinner bonding material as necessary.

In the friction stir welding method described in Japanese Patent Application Laid-Open No. 10-249553, it is necessary to control the angle of the probe to be constant by inclining the probe. Further, according to this method, it is not possible to form a slope by building up the corner portion of the butted portion of the joining material. Further, when an arc surface is formed at the corner, there is a problem that a part of the joining material is cut off.

Furthermore, in the friction joining method described in Japanese Patent Application Laid-Open No. 11-5179, the backing plate is only a flat plate and has a groove. This plate cannot be used and cannot be butt-joined. Further, since there is a possibility that the welding of the processed member may be insufficient due to the joining, an unmelted portion may be generated at the back seam portion of the melting portion, and the back seam may be joined again using a heat source such as an arc or a laser.

The present invention has been made in view of such a problem, and even in the case where there is a step, a member having a joint having a clean joint surface and good strength without unplastic flow is produced. An object of the present invention is to provide a joining member that can be obtained and a friction stir welding method therefor.

[0013]

A joining member according to the present invention is a joining member obtained by joining butted portions of joining materials having different plate thicknesses by friction stir welding, wherein the friction stir welding of the joining material is performed. The stepped portion of the butted portion on the side is overlaid.

[0014] In the friction stir welding method according to the present invention, the first bonding material and the second bonding material having a plate thickness larger than that of the first bonding material are butted, and the first and second bonding materials are joined. Arranged such that a gap is formed between the butting portion and a backing plate having a step portion corresponding to the height of the step portion of the butt portion on the surface opposite to the surface on which friction stir welding is performed, The probe is pressed into the butting part from the construction side of the friction stir welding of the butting part while being rotated, and further moved relatively along the butting part while rotating the probe, thereby plasticizing the material by frictional heat. The method is characterized in that the first and second joining materials are joined while causing the gap to be filled with the fluidized material.

In this case, it is preferable that a circular arc surface projecting toward the gap is formed at a corner of the step portion on the side of the butting portion.

It is preferable that an end face of the step portion on the side of the butting portion is a slope.

Further, it is preferable that a filler is disposed in the space.

In the present invention, in a joining member in which butting portions of joining materials having different plate thicknesses are joined by friction stir welding, a step portion of the opposite joining portion where the joining materials are subjected to friction stir welding is built up. By doing so, a joining member having a clean and strong joining portion can be obtained.

Further, in the present invention, the first joining material and the second joining material having a greater plate thickness than the first joining material are butted, and the friction stir welding of the first and second joining materials is performed. A backing plate having a step portion corresponding to the step height of the butt portion is arranged on the surface opposite to the surface on which the butt portion is to be constructed so that a gap is formed between the butt portion and the backing plate, and friction stirring of the butt portion is performed. The probe is pressed into the butted part from the construction surface side of the joint while rotating, and the material is plastically flowed by frictional heat by moving the probe relatively along the butted part while rotating the probe. Since the first and second joining materials are joined while being filled in the gap, the unplasticized flow portion is eliminated, and the plastically flowed material is filled in the gap formed between the butted portion and the backing plate, Burrs may occur It can be obtained a member having a clean and robust joints without.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A joining member and a friction stir joining method according to an embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing a joining member according to a first embodiment of the present invention, and FIG.
It is a schematic diagram which shows the friction stir welding method concerning Example of this.

As shown in FIG. 1, the joining member according to the present embodiment has a first joining material 1 having a thickness t _{1 and} a second joining material having a thickness t _{2 which} is greater than the first joining material 1. The material 2 is butted so that the surface thereof is flush with the surface, and the probe 11 is press-fitted from the opposite side of the step (step portion) 13 of the butted portion 12 while rotating the probe 11 as shown in FIG. The probe 11 is moved along the abutting portion 12 between the first and second probes.
Are relatively moved with respect to the joining materials 1 and 2 of FIG. The step 13 on the side opposite to the side on which the friction stir welding is performed is provided with a built-up 6 in a concave shape.

The joining member 5 having the above configuration is
The surface to be subjected to the friction stir welding is flush with the surface, and the step 13 formed on the opposite side of the surface to be formed has the concave buildup 6, so that the step 13 becomes a starting point of stress concentration. No, the fatigue strength is improved. Also, the bonding strength is high,
It is possible to obtain the joining member 5 having a beautiful appearance and a good joining portion.

Hereinafter, a friction stir welding method according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings. First, as shown in FIG. 2, a first bonding material 1 having a thickness t _{1 and} a second bonding material 2 having a thickness t _{2 which} is larger than the first bonding material 1 are flush with each other. , So that a step 13 is formed on the back surface.

Next, on the backing plate 3 having the step portion 30 having a height corresponding to the height of the step 13, the first bonding material 1 and the first 2 joining materials 2
And place. Since the height of the step portion 30 is equal to the height of the step 13, the opposite surface of the step 13, that is, the surface of the first bonding material 1 and the surface of the second bonding material 2 have the same height. The surfaces of the first bonding material 1 and the second bonding material 2 are flush with each other. The step portion 30 has such a shape that a gap 14 is formed between the butted portion 12 of the first bonding material 1 and the second bonding material 2 and the backing plate 3. In the present embodiment, a corner 2 at which the second bonding material 2 and the backing plate 3 come into contact with each other is provided at a corner of the step 30 on the side of the butted portion 12.
The arc-shaped surface 4 that extends from “a” to the surface of the step portion 30 on the side of the first bonding material 1 is formed to project toward the gap 14.

The first bonding material 1 and the second bonding material
1st joining to the butting portion 12 with the joining material 2
The surface where the material 1 and the second bonding material 2 are flush (friction stir welding)
The probe 11 is integrally formed at the tip from the side of the joint
The tool 10 is rotated, and the rotating probe 1
1 against the butting portion 12, and the professional
Softening and plasticizing the contact part between the probe 11 and the butt 12
Then, while being stirred by the probe 11,
2, the thickness t of the first bonding material 1 ₁than
Press-fit deeply so as not to touch the arc surface 4
12 is allowed to plastically flow. Further, the probe 11 is rotating.
The probe 11 along the butt 12
Relative to the first bonding material 1 and the second bonding material 2
While filling the voids 14 with the fluidized material,
The joining material 1 and the second joining material 2 are friction stir welded.

In the present embodiment, the probe 11 is made to penetrate deeper into the backing plate 3 than the first joining material 1 having a small thickness by the friction stir welding method as described above.
Since the butting portion 12 and the filler 7 are caused to plastically flow by the frictional heat caused by the rotation of the shaft, the unstirred portion is eliminated, and the butting portion 12 is entirely plastically flowed, and the plastically flowing member is filled between the step 13 and the arc surface 4. . For this reason, an unplastic flow portion is not formed in the butted portion 12, and the concave buildup 6 having a clean appearance and high bonding strength without generating burrs or the like.
The joining member 5 can be obtained by joining members having different thicknesses having joining portions formed on the steps 13.

Since the step 13 is surrounded by the backing plate 3, it is possible to prevent the material from being scattered due to the press-fitting and movement of the rotating probe 11.

In this embodiment, the dimensions and joining conditions of each member are, for example, that the first joining material 1 and the second joining material 2 are made of JIS 6N01 T5 material, thickness t ₁ of 2.0 mm, the thickness t ₂ of the second bonding material 2 is 4.0 mm, the rotational speed of the tool 10 2500rp
m, the penetration depth of the probe 11 is 2.5 mm, and the radius of curvature of the arc surface 4 is 2.0 mm.

Next, a second embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 3 shows a second embodiment of the present invention.
FIG. 4 is a schematic view showing a joining member according to the second embodiment, and FIG. 4 is a schematic view showing a friction stir welding method according to a second embodiment of the present invention. The same components as those in the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The present embodiment differs from the first embodiment in that, as shown in FIG. 3, the joining member 5 has a built-up 9 formed on the step 13 having a linear slope. In addition, in the friction stir welding method, as shown in FIG. 4, the end face of the step portion 30 of the backing plate 3 on the side of the butting portion 12 is the slope 8, and the first joining member 1 and the second joining member A gap 14 having a trapezoidal cross section is formed by the backing plate 2 and the backing plate 3, and the gap 14 has a first joining material 1, a second joining material 2, and a step portion 3.
The present embodiment is different from the first embodiment in that the columnar filler 7 is arranged so that the outer peripheral surface is in contact with the 0 slope 8.

In the present embodiment, by adopting the above-described configuration, the construction surface on which the friction stir welding is performed is flush, and the step 13 formed on the opposite side of the construction surface has a sloped surface. Since the overlay 9 is formed on the base member, the joining member 5 having a high joining strength, a beautiful appearance, and a good joining portion can be obtained.

In the friction stir welding method according to this embodiment, the surface of the butted portion 12 is flush (the surface on which friction stir welding is performed).
While rotating the tool 10 from the side, the probe 11 is pushed against the butting portion 12, the contact portion between the probe 11 and the butting portion 12 is softened and plasticized by frictional heat, and the tool 10 is rotated until it reaches the backing plate 3. The probe 11 is pressed into the butting portion 12, the probe 11 is rotated to agitate the butting portion 12, and the probe 11 is moved along the butting portion 12 relative to the first and second bonding materials 1 and 2. In this way, all butting portions 12 of the first bonding material 1 and the second bonding material 2 are plastically flowed, and the filler 7 is also plastically flowed to fill the gap 14 having a trapezoidal cross section. Thereby, as shown in FIG. 3, it is possible to obtain the joining member 5 in which the slope-shaped overlay 9 is formed on the step 13.

In this embodiment, the slope 8 is formed on the end face of the step portion 30, the cross section of the gap 14 is trapezoidal, the column-shaped filler 7 is arranged in the gap 14, and the probe 11 has a plate thickness. The butt portion 12 and the filler 7 are made to flow deeper than the thin first joining material 1 to the backing plate 3 and the abutting portion 12 and the filler 7 are caused to flow plastically by frictional heat generated by the rotation of the probe 11. 7 are plastically flowed, and the gap 14 is filled with the plastically flowing bonding material and filler 7. For this reason, an unplastic flow portion is not formed in the abutting portion 12, and the joining member 5 having the joining portion on which the slope-like overlay 9 having a beautiful appearance and high joining strength is formed without generating burrs or the like is formed. Can be.

By arranging the columnar filler 7 so as to be in contact with the first bonding material 1, the second bonding material 2 and the slope 8 in the space 14, the space 14 can be filled. The base materials of the first bonding material 1 and the second bonding material 2 can be modified. The void 14 is simply formed by the filler 7.
When filling, the filler 7 is preferably the same metal or alloy as the first bonding material 1 and the second bonding material 2.
When modifying the base material, the material of the filler 7 may be appropriately selected depending on the purpose of the modification. For example, when considering improvement in strength, a filler 7 having higher strength may be used.

Further, since the step 13 is surrounded by the backing plate 3, it is possible to prevent scattering of the material due to press-fitting and rotation of the probe 11.

In the present invention, since the voids 14 are filled with a plastically flowed metal, a filler or the like can be used as necessary to prevent the formation of concave portions on the surface.

In the present invention, the dimensions and joining conditions of each member are, for example, that the first joining material 1 and the second joining material 2 are made of JIS 6N01 T5 material, and that the first joining material 1 The plate thickness t ₁ is 1.0 mm, and the plate thickness t 2 of the second bonding material ₂
Is 3.0 mm, the rotation speed of the tool 10 is 1800 rpm,
The penetration depth of the probe 11 is 3.0 mm, the material of the filler 7 is T5 material of JIS 6N01, and the diameter thereof is 1.0.
mm.

[0038]

As described above in detail, according to the present invention, in a joining member in which butting portions of joining materials having different plate thicknesses are joined by friction stir welding, the opposite side where the friction stir welding of the joining materials is performed. Since the step portion of the butted portion is overlaid, a joining member having a clean and strong joining portion can be obtained.

According to the present invention, the first joining material and the second joining material having a thickness greater than that of the first joining material are abutted to each other, and the friction stir welding of the first and second joining materials is performed. A backing plate having a step portion corresponding to the step height of the butt portion is arranged on the surface opposite to the surface on which the butt portion is to be constructed so that a gap is formed between the butt portion and the backing plate, and friction stirring of the butt portion is performed. The probe is pressed into the butted part from the construction surface side of the joint while rotating, and the material is plastically flowed by frictional heat by moving the probe relatively along the butted part while rotating the probe. Since the first and second joining materials are joined while being filled in the gap, the unplasticized flow portion is eliminated, and the plastically flowed material is filled in the gap formed between the butted portion and the backing plate, Burrs may occur It can be obtained a member having a clean and robust joints without.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a joining member according to a first embodiment of the present invention.

FIG. 2 is a schematic view illustrating a friction stir welding method according to a first embodiment of the present invention.

FIG. 3 is a schematic view showing a joining member according to a second embodiment of the present invention.

FIG. 4 is a schematic view illustrating a friction stir welding method according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; 1st joining material 2; 2nd joining material 2a; Corner 3; Backing plate 4; Arc surface 5; Joining member 6, 9; Overlay 7; Filler 8; Slope 10; Tool 11; 12; Butt 13; Step 14; Void 30; Step

Claims (5)

[Claims] 1. A joining member in which butting portions of joining materials having different plate thicknesses are joined by friction stir welding, a step portion of the joining portion of the joining material on the opposite side where the friction stir welding is performed is built up. A joining member, characterized in that: 2. A first joining material and a second joining material having a thickness greater than that of the first joining material are butted, and friction stir welding is performed on the first and second joining materials. A backing plate having a step portion corresponding to the height of the step of the butt portion on the surface opposite to the surface is arranged so that a gap is formed between the butt portion and the backing plate, and friction stir welding of the butting portion is performed. The material is plastically flowed by frictional heat by rotating and pressing the probe into the butting portion from the construction surface while rotating the probe, and further moving the probe relatively along the butting portion while rotating the probe. And joining the first and second joining materials while filling the gaps with the friction stir welding method. 3. The friction stir welding method according to claim 2, wherein an arc surface projecting toward the gap is formed at a corner of the step portion on the side of the butting portion. 4. The friction stir welding method according to claim 2, wherein an end surface of the step portion on the side of the butting portion is a slope. 5. The friction stir welding method according to claim 2, wherein a filler is disposed in the gap.