JP2003025077A - Fixture for friction-stir welding and friction-stir welding method using the fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixture for friction-stir welding with which a stable welded part satisfying a desired strength without any defect can be obtained and further, improvement of the productivity can be obtained, and a method for friction-stir welding using the fixture. SOLUTION: In the fixture 1 or friction-stir welding provided with a columnar rotator 2 and a probe 3 projected along the rotating axis from the tip surface of the rotator 2, a spiral groove 7 is disposed on the circumferential surface of the probe 3 and is formed so that the volume of the probe 3 at the tip side becomes smaller than the volume at the rotor 2 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction stir welding jig and a friction stir welding method using the same, and more particularly to a friction stir welding jig having a spiral groove on the outer peripheral surface of a probe and The present invention relates to a friction stir welding method using the same.

[0002]

2. Description of the Related Art Conventionally, as a method for joining aluminum alloys, arc welding such as TIG and MIG has been generally used, but there is a risk that the vicinity of the joint is softened by welding heat and the strength is lowered. Therefore, a friction stir welding method has been proposed in which a cylindrical probe is inserted into a joint while rotating and the material of the joint is plastically fluidized by frictional heat to join. In this friction stir welding method, various probe shapes have been studied in order to improve the stirring effect. For example, in Japanese Patent Laid-Open No. 10-249551, a ridge or a groove is spirally formed on the outer peripheral surface of the probe. Disclosed is a jig for friction stir welding.

[0003]

However, in the friction stir welding jig disclosed in the above publication, the welding speed is relatively low (for example, the rotation speed is 1500 rpm,
In the case of a moving speed of 500 mm / min), sufficient friction stirring can be performed to satisfy the bonding strength, but a higher speed (for example, a rotation speed of 2000 rpm or more, a moving speed of 10).
In the case of a joining speed of 00 mm / min or more), there is a possibility that the stirring effect is reduced, the joining strength is reduced, and burrs are generated in the appearance.

Therefore, according to the present invention, a friction stir welding jig and a jig for the friction stir welding which can obtain a stable joining portion satisfying a desired strength without defects and further improving productivity can be used. It is a technical problem to provide a conventional friction stir welding method.

[0005]

In order to solve the above-mentioned technical problems, the present invention provides a friction provided with a cylindrical rotor and a probe protruding on the rotation axis of the tip end surface of the rotor. In the stirring and joining jig, a spiral groove is provided on the outer peripheral surface of the probe, and the groove is formed so that the volume on the tip side of the probe is smaller than the volume on the rotor side of the probe. And a jig for friction stir welding.

According to the jig for friction stir welding according to the present invention, the spiral groove provided on the outer peripheral surface of the probe is
Since the volume on the tip side is smaller than the volume on the rotor side of the probe, inserting the probe into the joint while rotating it is effective for friction stir in the radial and circumferential directions of the probe. It is possible to generate plastic flow in the axial direction of the probe as well as the material of the joint, and in particular, rotate the probe in the same direction as the traveling direction of the groove spiral from the probe tip side to the rotor side. In this case, the plastic flow of the material toward the tip side of the probe is enhanced and the stirring effect can be increased. Therefore,
It is possible to obtain a stable bonded portion that satisfies the desired strength without defects, and it is also possible to improve productivity by increasing the bonding speed.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a friction stir welding jig and a friction stir welding method using the jig according to one embodiment of the present invention. FIG. 1 shows a probe inserted into a butted member. FIG. 2 is a front sectional view (before welding), FIG. 2 is a main axial sectional view of a jig for friction stir welding, and FIG. 3 is a vertical sectional view showing a state in which a probe is inserted and friction stir is performed (view A in FIG. 1). ).

As shown in FIGS. 1 and 2, the friction stir welding jig 1 includes a cylindrical rotor 2 and a rotary shaft 1 of the rotor 2.
0 and a probe 3 protruding from the top end thereof, and can be rotated at a high speed by a driving device (not shown).

The diameter d of the probe 3 is set smaller than the diameter D of the rotor 2 at the shoulder 4, and the tip of the probe 3 is formed in a spherical shape. At least one spiral groove 7 is provided on the outer peripheral surface of the probe 3, and this groove 7 is on the tip side of the probe 3 with respect to the volume of the groove base end portion 7a on the rotor 2 side of the probe 3. The groove tip portion 7b is formed to have a small volume.

The shoulder 4 of the rotor 2 is a concave surface inclined from the outer periphery toward the probe 3, and a concave portion 8 is formed. If the volume of the concave portion 8 is too large, the amount of material that enters will be too large and defects will easily occur in the joint portion. If the volume of the concave portion 8 is too small, the agitated material will not be able to be sufficiently stored and the stirring effect will be increased. The volume of the concave portion 8 (excluding the scattered portions of the dots in FIG. 2 and the occupied volume portion of the probe 3) is not sufficient, so the probe 3
It is desirable that the area is formed in a range that satisfies 0.3 to 0.8 times the volume of the portion (cross-hatched portion in FIG. 2) protruding from the concave portion 8 of FIG.

While rotating the friction stir welding jig 1 at a high speed, the joining direction of the rotor 2 is joined to the joining portion 12 of the member 5 in which the members 5a and 5b are butted and held in that state, as shown in FIG. 6 The rear (right side in FIG. 3) shoulder 4a bites into the upper surface of the member 5, and the rotor 2 and the probe 3 are inclined at the advanced angle θ which is the inclination angle of the rotary shaft 10 with respect to the perpendicular 11 of the member 5, 3 is inserted, the shoulder 4 of the rotor 2 is brought into contact with the upper surface of the member 5, and is moved in the joining direction 6 (leftward in FIG. 3) along the abutting portion (joint portion 12) of the member 5 to cause friction. Perform stir welding.

At this time, by rotating the rotor 2, frictional heat is generated by the sliding of the probe 5 and the shoulder 4 and the member 5, and the material near the contact portion of the friction stir welding jig 1 is softened and stirred. The materials of the member 5a and the material of the member 5b are mixed with each other to cause plastic flow, and the members 5a and 5b
b can be joined.

Here, the spiral groove 7 provided on the outer peripheral surface of the probe 3 has a groove tip end portion which is closer to the tip end of the probe 3 than the volume of the groove base end portion 7a which is the rotor 2 side of the probe 3. Since the volume of 7b is formed to be small, when the probe 3 is inserted into the joint 12 while rotating, frictional stirring in the radial direction and the circumferential direction of the probe 3 is effectively performed, and the joint 3 is also formed. The material of No. 12 can also generate plastic flow in the axial direction of the probe 3, and in particular, the probe 3 is in the same direction as the traveling direction of the spiral of the groove 7 from the tip end side of the probe 3 to the rotor 2 side (in FIG. 1). When rotated in the counterclockwise direction when viewed from above the paper surface), the plastic flow of the material toward the tip side of the probe is increased, and the stirring effect can be increased. Therefore, it is possible to obtain a stable bonded portion that satisfies the desired strength without defects, and it is also possible to improve productivity by increasing the bonding speed.

The advanced angle θ is preferably 3 ° or more in order to sufficiently plastically flow the material. Further, the advanced angle θ and the diameter D of the rotor 2 are comprehensively determined in consideration of the space of the joint and the influence of frictional heat.

[0016]

EXAMPLES Next, examples of the present invention will be described more specifically in comparison with comparative examples.

In both Examples and Comparative Examples, aluminum alloy extruded material (A6N
01-T5) butting the member 5a and the member 5b but holding the state (joint 12)
And the cylindrical probe 3 having a diameter d of 6 mm,
Inserted at an advanced angle θ of 4.5 °, rotation speed 2500 rp
Friction stir welding was performed under the conditions of m and welding speed (moving speed) of 1000 mm / min. In any of the friction stir welding jigs 1, the diameter D of the rotor 2 is 20 mm,
The tip of the probe 3 was spherical and the length L was 4.5 mm.

The outer peripheral surface of the probe 3 has the groove shape shown in Table 1. In Examples 1 to 4, the spiral groove 7 is M6 based on JIS from the rotor 2 side of the probe 3 to the second round.
The metric coarse thread (pitch: 1 mm) of the above is provided from the third round onward to the tip side of the probe 3 and the shape of the metric fine thread of M6 (pitch: 0.75 mm). That is,
This groove 7 is a groove base end portion 7a which is on the rotor 2 side of the probe 3.
The groove tip portion 7b on the tip end side of the probe 3 is formed to have a smaller volume than the volume. Comparative Examples 5-6
Is not provided with a groove, Comparative Example 7 has an M6 metric coarse thread shape on the entire circumference, and Comparative Example 8 has an M6 metric fine thread shape from the rotor 2 side of the probe 3 to the second cycle. ,
From the third round onward, the shape of an M6 metric coarse thread is applied from the probe 3 to the tip side.

The shoulder 4 of the rotor 2 is a concave surface inclined from the outer periphery toward the probe 3, and a concave portion 8 having a volume ratio shown in Table 1 is formed. This volume ratio is the ratio of the volume of the concave portion 8 to the volume of the portion (cross-hatched portion in FIG. 2) protruding from the concave portion 8 of the probe 3.

The rotation direction of the jig 1 for friction stir welding is the same as the traveling direction of the spiral of the groove 7 provided in Examples 1 to 4 and Comparative Examples 7 to 8 from the tip end side of the probe 3 to the rotor 2 side. In the direction (counterclockwise when viewed from above in FIG. 1).

After joining, the joint efficiency was investigated after being sufficiently cooled and solidified, and the results are also shown in Table 1. The joint efficiency here is the ratio of the strength at the joint to the strength (tensile strength) of the base metal before joining.

[0022]

[Table 1]

As shown in Table 1, the groove 7 is formed so that the volume of the groove tip end portion 7b on the tip end side of the probe 3 is smaller than the volume of the groove base end portion 7a on the rotor 2 side of the probe 3. It was confirmed that all of Examples 1 to 4 that are performed have better joint efficiency than Comparative Examples 5 to 8. In particular, the recess 8
Of Comparative Example 2 in which the volume ratio of R is 0.5 to 0.6
Nos. 3 to 3 had a joint efficiency of 80% or more and were found to have excellent bondability. On the other hand, Comparative Examples 5 to 5
It was revealed that No. 8 had poorer joint efficiency than Examples 1 to 4.

In the above-described embodiment, the friction stir welding jig 1 is shown in which one groove is provided on the surface of the cylindrical probe 3, but in the practice of the present invention, the probe has a conical shape. Even if the groove is present or the groove is formed in a double or triple spiral shape, the same effect of improving the bondability as in the above-described embodiment can be obtained. Further, according to the present invention, a stable joining portion can be obtained even at superposing joining other than butt joining, or at a joining speed which could not be stably joined by using an aluminum die casting material or the like.

Further, since the jig for friction stir welding according to the present invention has a high stirring effect, depending on the material of the members, it is possible to join at a range in which the rotation speed is slower than in the conventional case, and distortion at the time of joining will occur. It is possible to further improve the strength reduction due to heat. As a result, it can be applied to an aluminum alloy structural member for a frame of an automobile, which requires a highly accurate assembling property.

[0026]

As described above, according to the present invention, it is possible to obtain a stable joint having a desired strength without defects and further to improve productivity, and to improve the friction stir welding. It is possible to provide a tool and a friction stir welding method using the tool.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of a friction stir welding method according to the present invention, showing a state before a probe is inserted into a butted member (before welding).

FIG. 2 is a main axial sectional view of the jig for friction stir welding shown in FIG.

FIG. 3 is a vertical cross-sectional view showing a state where a probe is inserted and friction stirring is performed in the embodiment shown in FIG. 1 (A in FIG. 1).
Sight).

[Explanation of symbols]

1 Jig for friction stir welding 2 rotor 3 probes 4 shoulder 7 groove 7a groove base end 7b groove tip 8 recess 12 Joined part (butted part) d Probe diameter D rotor diameter θ Advance angle (tilt angle)

Claims (3)

[Claims] 1. A jig for friction stir welding, comprising a cylindrical rotor and a probe protruding on a rotation axis of a tip end surface of the rotor, wherein a spiral groove is provided on an outer peripheral surface of the probe. The groove is formed so that the volume on the tip side of the probe is smaller than the volume on the rotor side of the probe. 2. The rotor according to claim 1, wherein a recess is provided at the tip of the rotor, and the volume of the recess is 0.3 to 0.8 times the volume of the portion of the probe protruding from the recess. A jig for friction stir welding, characterized in that it is formed in a range that satisfies the conditions. 3. A friction stir welding method using the jig for friction stir welding according to claim 1 or 2, wherein the rotor is a traveling direction of a spiral of the groove from the probe tip side to the rotor side. The friction stir welding method is characterized by rotating in the same direction as.