JP2002346766A - Friction stir welding method of members having different thickness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain occurrence of defect at a joined part in the case of applying a butt-joint with a friction-stir welding method under a state having the difference of the surface levels in the joining materials. SOLUTION: A member having larger thickness is disposed to the larger side of relative velocity between a rotating tool and a material to be joined decided with the rotating direction of the rotating tool and the joining direction to perform the friction stir welding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary tool provided with a plurality of members to be joined having different thicknesses and a pin-shaped probe protruding from an end face of a columnar member. The present invention relates to a method of friction stir welding by inserting into a surface.

[0002]

2. Description of the Related Art A rotating tool made of a material harder than a member to be joined is inserted into a joint of the member to be joined while rotating the tool.
There is a friction stir welding method in which welding is performed using frictional heat generated between a tool and a member to be welded.
No. 838.

In this type of friction stir welding method, it is known that a rotary tool is inclined with respect to the surface of a member to be welded and the tip of a probe is moved forward in the direction of welding in order to ensure the soundness of the welded portion. ing.

[0004] When joining members to be joined having different thicknesses, a method of joining by tilting the rotation axis of a rotary tool to a lower side with respect to a butt surface of the members to be joined is disclosed in, for example, JP-A-10-249553. Gazette, JP-A-2000-167
676 and the like. JP-A-2000-1
Japanese Patent Application Laid-Open No. 67676 also discloses that a backing having a step or an inclination is used in accordance with a difference in thickness between members to be joined.

[0005]

In the above prior art,
No description is given of the relationship between the positions of a plurality of members to be joined having different thicknesses, the rotation direction of the rotary tool, and the joining progress direction.

When a plurality of members to be welded are butt-joined by a friction stir welding method using a rotary tool, the relative speed of the rotary tool and the member to be welded at a friction portion differs depending on the position of the member to be welded. For example, the above-described relative speed is different between the member to be joined located on the left side and the member to be joined located on the right side with respect to the joining progress direction. It has been found that the left-right asymmetry of the relative speed has a significant effect on securing the soundness of the joint when butt-joining a plurality of members having different thicknesses.

Accordingly, an object of the present invention is to provide a friction stir welding method for soundly joining a plurality of members having different thicknesses in consideration of the difference in the relative speed.

[0008]

According to the present invention, a member having a large thickness is located at a position where the relative speed between the rotating tool and the material to be welded is determined by the rotating direction of the rotary tool and the joining direction. And to perform friction stir welding.

Specifically, when a member to be joined having a large thickness is located on the left side in the joining progress direction, the joining is performed by rotating the rotating tool clockwise. On the other hand, when a member to be joined having a large thickness is positioned on the right side with respect to the joining progress direction, the joining is performed by rotating the rotating tool counterclockwise.

Also in the present invention, it is desirable that the rotation axis of the probe of the rotary tool is inclined toward the lower side of the member to be joined. Thereby, generation of burrs, size of burrs, and the like can be suppressed.

It is preferable that the rotating tool is inclined with respect to the joining direction and the tip of the probe is moved forward.

According to the present invention, the relative speed between the rotating tool and the frictional portion of the member to be welded is determined by the relationship between the welding direction and the rotating direction of the rotating tool. This is based on the fact that it has been clarified that the member on the left side in the direction has a higher relative speed and that a thicker member disposed on the side with the higher relative speed results in a sounder joint.

[0013]

FIG. 1 shows an example of a joining method according to the present invention. An example is shown in which friction stir welding is performed by abutting two members consisting of a joined member 2 having a large thickness and a joined member 3 having a small thickness such that a step is formed at the upper end of the joining surface. The rotating tool 1 has a pin-shaped probe 9 on an end surface of a columnar member 10. The rotating direction of the rotating tool is clockwise as viewed from above the rotating tool. The joining direction is the direction indicated by arrow 100. FIG.
In the case of the example, the member 2 having a large thickness has a large relative speed between the rotary tool and the member to be joined. The side where the relative speed is large is hereinafter referred to as an advanced side.

FIG. 2 shows an example in which the configuration is exactly the same as that of FIG. 1 and only the rotation direction of the rotary tool is counterclockwise. In this example, the member 3 having a small thickness has a large relative speed between the rotating tool and the member to be joined. Therefore, in the example of FIG. 2, the member 3 to be joined having a small thickness is on the advanced side.

FIG. 3 shows a friction stir welded joint.
FIG. 3 shows a conceptual diagram when viewed from above a rotating tool. In FIG. 3, the bonding proceeds from right to left on the paper. The rotating tool 1 rotates counterclockwise. The rotation tool 1
The bead 5 is formed by being inserted into the butted surface 6 of the members to be joined 4a and 4b. In the example of FIG. 3, the relative speed of the rotating tool and the member to be joined at the friction portion is higher on the member 4a side and slower on the member 4b side.

An aluminum alloy A5182 having a thickness of 2 mm is used for the member 2 to be joined, and an aluminum alloy A5182 having a thickness of 1 mm is used for the member 3 to be joined.
mm aluminum alloy A5182 was used. The welding speed is 500mm / min and the number of rotations of the rotary tool is 1500
Minutes.

The positional relationship between the rotary tool 1 and the workpieces 2 and 3 is as shown in FIGS. 4 and 5 when shown by a trigonometric method. In other words, the tip of the probe of the rotary tool was advanced in the joining progress direction indicated by the arrow, as shown in FIG. θ ₁ of the angle was in three times. In addition, the rotating tool was inclined to a smaller thickness as shown in FIG. The inclination angle θ ₂ was set to 7 degrees.

FIG. 6 summarizes the experimental results. When the member to be joined having a large thickness was arranged on the advanced side as shown in FIG. 1, no defect occurred on both the surface and the inside. On the other hand, when the member to be joined having a small thickness was disposed on the advanced side as shown in FIG. 2, no defect was generated on the surface but a defect was generated inside. The cross-sectional photograph shows the butted portion viewed from the side. A member to be joined having a small thickness is arranged on the right side, and a member having a large thickness is arranged on the left side. The surface of the joined portion is a slope.
In the comparative example of FIG. 2, the presence of a defect is recognized inside. In the cross-sectional photographs, in both cases of FIGS. 1 and 2,
Burrs were observed in the upper part on the left side, but their size was small.

As described above, by the method of the present invention, that is, by disposing a material to be joined having a large thickness on the advanced side, the quality of the joint can be improved and a sound joint having few defects can be obtained. .

In FIG. 1, even when the arrangement of the materials to be joined was reversed and the rotating direction of the rotary tool 1 was reversed, a sound joint having no defects on the surface and inside was obtained.

FIG. 7 is a conceptual diagram showing a case where cylindrical members having different thicknesses are joined. Aluminum alloy A50
83 and a thick cylindrical member 11 made of aluminum alloy A5083
And the butted surfaces 6 were joined. The wall thickness is 10 mm for the larger thickness and 5 mm for the smaller thickness. The inner diameter of each of the cylindrical members 11 and 12 is 500 mm. Therefore, the cylindrical member has no step on the inner surface side of the butted surface, and has a step of 5 mm only on the outer surface side.

The welding speed was 400 mm / min, and the rotation speed of the rotary tool was 1000 revolutions / min. Further, a member having a large thickness was arranged on the right side with respect to the joining traveling direction 100, and the rotating tool was rotated counterclockwise. The rotating tool advanced the probe tip in the joining traveling direction 100, and the angle θ ₁ was set to 3 degrees. Further rotating tool is inclined smaller in thickness, the inclined angle theta ₂ was set to 6 degrees.

As a result of the joining experiment, a sound joint having no internal defect was obtained.

[0024]

According to the present invention, a sound joint having few defects can be obtained in a method of butt joining a plurality of members having different thicknesses by friction stir welding.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a joining method according to the present invention.

FIG. 2 is a perspective view showing a joining method of a comparative example.

FIG. 3 is a conceptual diagram of a joint viewed from above a rotary tool.

FIG. 4 is a conceptual diagram showing an inclination of a rotary tool in a joining progress direction.

FIG. 5 is a conceptual diagram showing the direction of inclination of the rotating tool with respect to the abutting surface.

FIG. 6 is a diagram comparing the soundness of a joint according to the present invention and a comparative example.

FIG. 7 is a perspective view in the case of joining cylindrical members having different thicknesses.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotary tool, 2, 3 ... Member to be joined, 5 ... Bead, 6
... butting surface, 9 ... probe, 10 ... columnar member, 100
… Joint progress direction.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazutaka Okamoto 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Masayuki Doi 7-1 Omikacho, Hitachi City, Ibaraki Prefecture No. 1 F Term in Hitachi Research Laboratory, Hitachi, Ltd. (Reference) 4E067 AA05 BG00 DA17 DC07 EC01 EC06

Claims (5)

[Claims] 1. A rotating tool provided with a pin-shaped probe protruding from an end face of a cylindrical member is inserted into a butted surface of a plurality of members to be joined having different thicknesses in a rotated state, In the method of performing friction stir welding by moving the rotary tool along the abutting surface, the thickness is determined in such a manner that the relative speed between the rotary tool and the workpiece is determined by the rotation direction of the rotary tool and the welding progress direction. A friction stir welding method characterized by disposing and joining members to be welded having a large size. 2. A rotating tool, which is provided so that a pin-shaped probe protrudes from an end surface of a cylindrical member, is inserted into a butted surface of a plurality of members to be joined having different thicknesses in a stepped manner, In the method of performing friction stir welding by moving the rotary tool along the abutting surface, a member to be welded having a large thickness is disposed on the left side with respect to the welding progress direction, and rotating the rotary tool clockwise. Characteristic friction stir welding method. 3. A rotating tool provided with a pin-shaped probe protruding from an end surface of a cylindrical member is inserted into a butted surface having a step of a plurality of members to be joined having different thicknesses, while rotating. In the method of performing friction stir welding by moving the rotating tool along the abutting surface, a member to be welded having a large thickness is arranged on the right side with respect to the welding progress direction, and the rotating tool is rotated counterclockwise. A friction stir welding method characterized by the following. 4. A friction stir welding method according to claim 1, wherein a rotation axis of a probe of said rotary tool is inclined to a lower side of said member to be welded. Method. 5. A friction stir welding method according to claim 1, wherein the tip of the probe of the rotary tool is joined with the tip of the probe moving forward in the joining progress direction. Joining method.