JP3262757B2 - Friction stir welding - Google Patents

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 method used for joining a metal material such as an aluminum material (including an aluminum alloy material).

[0002]

2. Description of the Related Art For example, as shown in FIG. 5, a circular metal hole (51a) provided at the center of a hexagonally shaped metal first joining member (51) is inserted into a circular metal hole (51a). The second joining member (52) is fitted to the first joining member (51) and the second joining member (52).
When joining the joining member (52) over the entire circumference of the fitting portion (A '), a friction stir welding method, which is one of the solid-phase joining methods, may be used.

The friction stir welding method will be described as follows. That is, as shown in FIG. 5B, a joining tool (60) in which a small-diameter pin-shaped probe (62) protrudes and is integrally provided on an end axis of a large-diameter cylindrical rotor (61).
The probe (62) is inserted into a part of the fitting portion (A ') of the first joining member (51) and the second joining member (52) while rotating the rotor (61). . Insertion is generally performed until the shoulder (61a) formed of the flat surface on the probe side of the rotor (61) comes into contact with both joining members (51) and (52).

Then, as shown in FIG. 6A, the probe (6) is moved along the fitting portion (A ') while the probe is inserted.
2) is moved relatively to both joining members (51) and (52). The probe (62) is generated by frictional heat generated by rotation of the probe (62) or frictional heat generated by sliding between the shoulder (61a) of the rotor (61) and the two joining members (51) and (52). In the vicinity of the contact portion with the probe (6), the two joining members (51) and (52) soften and
2) While being stirred by the probe (62), the softening and stirring portion is moved backward in the traveling direction of the probe (62) such that the softening and stirring portion receives the traveling pressure of the probe (62) and fills the passage groove of the probe. After plastically flowing in a wraparound manner, it rapidly loses frictional heat and is cooled and solidified. This phenomenon is repeated sequentially with the movement of the probe (62), and finally the two joining members (51) and (52) are joined at the fitting portion (A '). In the same figure, (W ′) is a joining bead portion formed by the friction stir welding, which is formed along the fitting portion (A ′).

According to such a friction stir welding method, since it is a solid-phase welding, there are advantages such as being not limited to the kind of metal material as a joining member, and being less deformed due to thermal distortion during welding.

By the way, the joining members (51) (5)
In the case of friction stir welding of 2), the probe (6
When (2) returns to the joining start end (W1 ') of the fitting portion (A'), there is no need to join any more, so FIG.
The probe (62) is connected to the joining member (51) as shown in FIG.
(52) must be withdrawn.

[0007]

However, when the probe (62) is pulled out in the axial direction from the surfaces of the joining members (51) and (52), the probe (62) is always attached to the joining end portion of the fitting portion (A '). 62) corresponding to the diameter and insertion depth of (5)
3) remains. Since the holes (53) locally reduce the joining strength, they must be removed or filled after joining is completed.

As the hole treatment means, a method of embedding a pin in the hole (53) and a method of filling the hole (53) with a molten metal by fusion welding such as TIG and MIG have been proposed. However, in the method of embedding the pin, since the pin is merely fixed by mechanical biting, the reliability in strength is poor.
Further, the fusion welding method has problems such as a decrease in bonding strength and thermal distortion caused by welding heat generated during welding.

[0009] In addition, although not shown, in the case where a joining portion whose end portion does not return to the starting end portion, for example, a joining member having a linear joining portion is subjected to friction stir welding, an end tab is provided at the end portion of the joining portion. After attaching the probe, it is effective to move the probe (62) to the end tab and then remove the end tab. However, this method is used when joining the joining members (51) and (52) having a joining portion whose end portion returns to the starting end portion (W1 ′), such as the above-mentioned turning joining or circumferential joining. This is not applicable because there is no termination.

It is also conceivable that the inserted probe (62) that has returned to the joining start end (W1 ') is pulled out from the end face of the first joining member (51) by changing its moving direction. In this method, a concave portion (not shown) is formed on the end face of the first joining member (51) as a pull-out trace of the probe, so that there is a problem that the appearance of the obtained joined product is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem. In a friction stir welding method for joining a joining member having a joining portion such that an end portion returns to a starting end portion, a hole after a probe is pulled out. It is an object of the present invention to provide a friction stir welding method that does not generate a concave portion or a concave portion.

[0012]

In order to achieve the above object, the present invention provides a joining member having a joining portion such that an end portion returns to a starting end portion, wherein a rotating probe is inserted into the joining portion. In the friction stir welding method of joining the joining members, the contact portion is softened by frictional heat and stirred, and the probe is relatively moved along the joining portion in an inserted state. The probe in the inserted state is moved to a discarded portion provided at a position other than the joint portion of the joining member by changing its moving direction.

According to this, when the joining is completed, by changing the moving direction of the probe in the inserted state, the moving direction of the probe is deviated from the extending direction of the joining portion, that is, the joining line direction. When the probe enters the discarded meat portion, the softened portion of the discarded meat portion that comes into contact with the probe plastically flows rearward, and fills the groove formed after passing through the probe. Next, the probe in the inserted state moved to the discarded meat portion is pulled out from the discarded meat portion. By doing so, the hole after the probe is pulled out will not remain at the joint,
Therefore, it is possible to prevent a decrease in the joint strength of the joint, and to improve the strength reliability of the joint. Thereafter, by further removing the discarded meat portion, the holes and recesses after the probe is pulled out of the joining member no longer remain, and therefore, it is possible to prevent the appearance of the bonded product from being deteriorated due to the holes and the recesses after the probe is drawn out, and therefore, The appearance of the joined product can be maintained.

Here, the discarded meat portion may be provided at any position other than the joint portion. However, it is preferable that the discarded meat portion is provided near the end portion of the joint portion, that is, near the start end portion. This is preferable in that the moving distance of the probe can be shortened and the probe can be promptly moved to the discarded meat portion, and as a result, the efficiency of the joining operation can be improved.

[0015]

FIG. 1 and FIG. 2 show one embodiment (first embodiment) of the present invention. In the figure, (1) is a plate-shaped first joining member formed in a hexagon, and (2) is a disc-shaped second joining member. These first
The second joining members (1) and (2) are both made of aluminum.

At the center of the first joining member (1), similarly to the first joining member (51) described in the above prior art,
A circular hole (1a) penetrating in the thickness direction is provided.
The first embodiment shown in FIG.
The circular hole (1a) of the first joining member (1)
The joining member (2) is fitted and the first joining member (1) is
This shows a case where friction stir welding is performed on the joining member (2) over the entire circumference of the fitting portion (A). Therefore, the fitting portion (A) becomes a joining portion between the two joining members (1) and (2). The thickness of the first joining member (1) and the thickness of the second joining member (2) are the same. Then, the circular hole (1) of the first joining member (1) is formed.
When the second joining member (2) is fitted in (a), the surface of the first joining member (1) and the surface of the second joining member (2) are flush.

Reference numeral (20) denotes a joining tool, in which a small-diameter pin-shaped probe (22) protrudes and is integrally provided on an end axis of a large-diameter cylindrical rotor (21). The probe (2) is rotated by rotating the rotor (21) at a high speed.
2) also rotates at high speed. The probe (22) and the rotor (21) are connected to the joining member (1).
It is made of a heat-resistant material that is harder than (2) and can withstand frictional heat generated at the time of joining.

At one end of the first joining member (1), a triangular plate-shaped waste portion (3) is integrally protruded. This discarded meat part (3), as described later,
The first joining member (1) is for keeping the extraction hole and the concave portion of the probe (22) from being left in the first joining member (1), and has the same thickness as that of the first joining member (1). It is flush with the surface of the member (1). In addition, V-shaped cut portions (3a) (3a) are provided on both side edges of the connection portion of the discarded meat portion (3) with the first joining member (1),
The waste meat portion (3) can be easily removed.

The friction stir welding according to the present invention is performed as follows. That is, the probe (22) that rotates integrally with the rotor (21) by rotating the rotor (21) is inserted into the fitting portion (A). Then, in the probe inserted state, the flat shoulder (21a) at the tip of the rotor (21) is brought into contact with the surfaces of the joining members (1) and (2) at the time of joining start or in the middle of softening during joining. A uniform joining state can be realized by preventing scattering of the material, and the joining member (1)
(2) The friction between the shoulder (21a) and the shoulder (21a) further generates frictional heat, which promotes softening of the contact portion with the probe or the vicinity thereof, and further forms unevenness on the surfaces of the joining members (1) and (2). It is preferable from the viewpoint of prevention.

Then, the probe (22) is relatively moved along the fitting portion (A) with the probe inserted. The probe (22) is caused by frictional heat generated by rotation of the probe (22) or frictional heat generated by sliding between the shoulder (21a) of the rotor (21) and the surfaces of the joining members (1) and (2). The joining members (1) and (2) are softened and agitated in the vicinity of the contact portion with the probe (22), and the softened and agitated portion receives advancing pressure of the probe (22) with the movement of the probe (22). After plastically flowing in such a manner as to go backward in the traveling direction of the probe (22) so as to fill the passage groove of (22), frictional heat is rapidly lost, and cooling and solidification is performed. This phenomenon is repeated sequentially with the movement of the probe (22), and the two joining members (1) and (2) are integrated and sequentially joined at the fitting portion (A). In FIG. 1A, (W) is a joining bead portion formed by the friction stir welding, and the fitting portion (A)
Are formed along.

When the probe (22) in the inserted state returns to the joining start end (W1) of the fitting portion (A), the two joining members (1) and (2) are connected to all of the fitting portion (A). Since the joining is performed over the circumference, the joining is completed. However, if the probe (22) is pulled out from the surface of the joining members (1) and (2) at the probe insertion position, as described in the above-described related art, As a result, a probe withdrawal hole is generated. Then, the moving direction of the probe (22) is changed, and FIG.
As shown in (2), the probe (22) is moved to the discarded meat part (3) in the inserted state. Thus, the probe (2
When 2) enters the discarded meat portion (3), the contact softening portion of the discarded meat portion (3) with the probe (22) plastically flows backward in the traveling direction of the probe (22), and the probe (22) This will fill the grooves that occur after passing. Therefore, no holes or recesses remain in the fitting portion (A), that is, the joining portion.

Next, the probe (22) thus moved to the discarded meat portion (3) is pulled out in the axial direction from the surface of the discarded meat portion (3). Then, as shown in FIG. 2 (a), the extraction hole (4) of the probe is formed in the discarded meat portion (3), and as shown in FIG. 2 (b), the discarded meat portion (3) is formed. 3) is cut and removed at the cut portions (3a) and (3a). By doing so, holes and recesses do not remain at the probe passage marks on the joining members (1) and (2), so that a joined product having a good joining state can be obtained.

Although not shown, the discarded meat portion (3)
The probe (22) moved to the above may be pulled out from the end face of the discarded meat portion (3), and then the discarded meat portion (3) may be removed.

In addition, a breaking groove (not shown) is previously provided in a connection portion of the discarded meat portion (3) with the first joining member (1).
May be formed, and the discarded meat portion (3) may be removed by breaking the discarded meat portion (3) in this groove.
This makes it possible to easily remove the discarded meat portion (3) as in the first embodiment.

FIG. 3 and FIG. 4 show another embodiment (second embodiment) of the present invention. This second embodiment includes two joining members (7) having a circular cross section.
A case where a member for a suspension arm of an automobile is manufactured by joining performed along the circumference of (8), that is, by circumferential joining.

First, the suspension arm member will be described. In the same figure, (8) has a member main body (second joining member) of the suspension arm member, and (7) has a circular bush mounting hole (5a) for press-fitting a vibration isolating bush (not shown). It is a bush mounting member (first joining member). The member body (8) is made of a rod-shaped extruded aluminum cylindrical pipe material having a predetermined length. (8a) is a hollow portion of the pipe material. The bush mounting member (7) is made of an aluminum forged product, and has a cylindrical portion (5) provided with the bush mounting hole (5a).
A columnar connecting portion (6) is integrally protruded from a part of the outer peripheral surface. The diameter of the connecting portion (6) is the same as the outer diameter of the member body (8). As shown in FIG. 3, the suspension arm member is provided on one end surface of the member body (8) with the bush mounting member (7).
By joining the end faces of the connecting portions (6) of the above, as shown in FIG. 4, the member main body (8) and the bush mounting member (7) are friction stir welded over the entire circumference of the butting portion (B). It is to be produced. Therefore, the butting portion (B) becomes a joining portion between the member main body (8) and the bush mounting member (7). In a state where the end face of the connecting portion (6) is abutted against one end surface of the member body (8), the outer peripheral surface of the member body (8) and the peripheral surface of the connecting portion (6) are flush.

Also, a part of the peripheral surface of the connecting portion (6) of the bush mounting member (7) is integrally formed with a throw-out portion (9) formed of a convex portion having a triangular cross section and a predetermined length. Has been established. One surface of the discarded meat portion (9) is flush with the peripheral surface of the connecting portion (6).

In the second embodiment, the friction stir welding is performed in substantially the same procedure as in the first embodiment. This will be briefly described below, focusing on differences from the first embodiment.

That is, the probe (22) of the joining tool (20) is inserted into the butting portion (B) from its outer peripheral surface while rotating. Then, with the probe (B) inserted, the member main body (8) and the connecting portion (6) along the butting portion (B).
Relatively in the circumferential direction. Along with this movement, as shown in FIG. 4A, the butted portions (B) are sequentially joined. In the same figure, (W) is a joining bead portion formed by the friction stir welding, which is formed along the butting portion (B).

When the inserted probe (22) returns to the joining start end (W1) at the butting portion (B), the joining is completed.
By changing the moving direction of 2), as shown in FIG. 7B, the probe (22) is moved to the discarded meat portion (9) in the inserted state. Then, the probe (22) is pulled out in the axial direction from the surface of the discarded meat portion (9). Although not shown, the probe (22) may be pulled out from the end face of the discarded meat portion (9). When the probe (22) is pulled out from the discarded meat portion (9) in this manner, a withdrawal hole (9) for the probe and a concave portion (not shown) are formed in the discarded meat portion (9). Then, the discarded meat portion (9) is cut and removed.
By doing so, holes and recesses do not remain in the probe passage traces in the bush mounting member (7) and the member main body (8), so that a joined product having a good joined state, that is, a suspension arm member can be obtained.

Although the first and second embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

For example, in the first and second embodiments,
Although the discarded meat portions (3) and (9) are previously provided integrally with the joining members (1) and (7), although not shown, a discarded meat portion is separately prepared and joined. It may be attached to a member. As the attachment means, for example, adhesion using an adhesive or pressing can be adopted.

[0033]

As described above, according to the present invention, a rotating probe is inserted into the joining portion of the joining member having the joining portion such that the end portion returns to the starting end portion, and the contact portion with the probe is frictionally heated. In the friction stir welding method of joining the joining members by relatively moving the probe along the joining portion in the inserted state while softening and stirring at, at the end of joining, the probe in the inserted state is According to the friction stir welding method according to the present invention, the moving direction is changed, and the moving member is moved to a waste meat portion provided at a position other than the joining portion of the joining member. The groove formed after the passage of the probe can be filled by the softened portion of the meat portion that makes contact with the probe. Therefore, even when a joining member having a joining portion whose end portion returns to the starting end portion is joined by the friction stir welding method, no hole or concave portion remains after the probe is pulled out at the joining portion, that is, joining of the joining portion A joined product having high strength and high strength reliability can be obtained. Further, after the probe is pulled out from the discarded meat portion, by removing the discarded meat portion, a hole or a concave portion after the probe is drawn out does not remain in the joining member, that is, a good-looking joined product can be obtained.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing one embodiment (first embodiment) of the present invention, wherein FIG. 1A is a perspective view in the middle of joining, and FIG. 1B is a perspective view in a state in which the probe is moved to a discarded meat portion. FIG.

FIGS. 2A and 2B are views showing the same embodiment, in which FIG. 2A is a perspective view showing a state in which a probe is pulled out from a discarded meat portion, and FIG. 2B is a perspective view showing a state in which the discarded meat portion is cut and removed;

FIG. 3 is a perspective view showing another embodiment (second embodiment) of the present invention before joining.

FIGS. 4A and 4B are views showing the same embodiment, wherein FIG. 4A is a perspective view in the middle of joining, and FIG.

5A and 5B are views showing a conventional friction stir welding, in which FIG. 5A is a perspective view of a state before fitting of two joining members, and FIG. 5B is a perspective view of a state after fitting of two joining members. FIG.

FIG. 6 is a view showing the disadvantages of the conventional friction stir welding;
FIG. 2 is a perspective view of a state in the middle of joining, and FIG. 2B is a perspective view of a state after the joining.

[Explanation of symbols]

1, 2 ... joining member 3 ... discarded meat part 4 ... probe withdrawal hole 7 ... bush mounting member of suspension arm member (joining member) 8 ... member body (joining member) 9 ... discarded meat part 10 ... probe withdrawal hole 20 ... Joining tool 22 ... Probe A ... Fitting part (joining part) B ... Butt part (joining part) W ... Joining bead part W1 ... Start end part

Continuation of the front page (56) References CJ Dawes, "An Induction to Friction Ion Stir Welding and Developments," Welding & Metal Fabrication, UK, TWI, Thurs. No. 1, P13-14, 16, National Diet Library Accepted February 13, 1995 (58) Fields surveyed (Int. Cl. ⁷ , DB name) B23K 20/12 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A joining member (1) (2) (7) having joining portions (A) and (B) such that an end portion returns to a starting end portion.
A rotating probe (22) is attached to the joint in (8).
Is inserted, and the probe (22) is relatively moved along the joining portion in the inserted state while softening and stirring the contact portion with the frictional heat, thereby frictionally stirring the joining member. In the joining method, when the joining is completed, the probe (22) in the inserted state is moved to the discarded meat portions (3) and (9) provided at positions other than the joining portion of the joining member by changing the moving direction. A friction stir welding method characterized in that: