JP2003154469A - Rotary tool for friction stirring and joining, and method for friction stirring and joining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of defects in the friction stirring and joining operation to join a work by holding the work between shoulders by using a rotary tool having a pin between the two shoulders. SOLUTION: The space between the two shoulders facing each other is set to be large on the pin side and small on the outer circumferential side. A cutting blade is formed on at least one of the two shoulders. By reducing the space between the two shoulders on the outer side part, a high pressure can be given to a friction-stirred metal in a joining process, and generation of any joining defects can be suppressed. In addition, the work is drilled by the cutting blade even during the joining operation, and the rotary tool can be drawn therefrom or inserted therein.

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 in which a rotary tool is inserted into a joint portion of materials to be welded and the friction heat generated by the rotation of the rotary tool is used for welding, and more particularly, a rotary tool. Regarding

[0002]

2. Description of the Related Art A friction stir welding method is performed by inserting a rotating tool made of a material harder than that of a material to be welded into a welding portion of the material to be welded and moving the rotating tool relative to the material to be welded while rotating the rotating tool. It is a method of joining by friction heat. This method is already known from Japanese Patent Publication No. 7-505090. That is, it utilizes the plastic flow phenomenon due to the frictional heat between the rotary tool and the material to be welded, and does not melt and weld the material to be welded as in arc welding. In addition, this joining method is different from the method of joining the materials to be joined by rotating them by frictional heat of each other as in the conventional rotary friction welding method. According to the friction stir welding method using the rotary tool, the materials to be welded can be continuously welded in the welding line direction, that is, in the longitudinal direction.

[0003]

A general rotary tool used in the friction stir welding method comprises a pin portion and a shoulder portion thicker than the pin portion. On the other hand, the rotary tool targeted by the present invention has a structure in which the pin portion is sandwiched by two shoulders with a constant space therebetween. When the rotary tool having this structure is used, the materials to be joined are sandwiched by the two shoulders so as to be sandwiched from the front and back surfaces. The rotating tool of this structure is the same as the special table 7
No. 505090.

It has been found that the following problems occur when joining with a rotary tool having a pin between two shoulders. (1) Since the material to be joined is joined so as to be surrounded by the two shoulders, the gap between the two shoulders greatly affects the joining quality. It has been found that when the distance between the outer side portion and the pin side (inner side) portion of the two shoulders facing each other is the same, the pressure of the material to be joined is insufficient and the frequency of occurrence of defects increases. (2) When some trouble occurs during the joining process and the joining is interrupted midway and the rotary tool is pulled out from the materials to be joined,
It is necessary to move the rotary tool to the start of the weld or the end of the weld. However, since the material to be welded is sandwiched between the two shoulders, movement of the rotary tool is impossible unless the material to be welded is cut or a hole is drilled. That is,
In order to pull out the rotary tool in the middle of welding, it is necessary to make a hole or cut in the material to be welded near the rotary tool. However, this hole is not realistic because it will be repaired and filled after joining. (3) Since the material to be joined is sandwiched between the two shoulders from both the front and back sides, when the thickness of the material to be joined is locally increased, frictional heat also increases and the thermal balance is lost, resulting in a joint defect. Is likely to occur. Further, when a part of the materials to be joined has a thick plate thickness, a large load is suddenly applied to the rotary tool, so that the rotary tool is easily damaged and the durability of the rotary tool is deteriorated.

The present invention solves these problems.

[0006]

The above problem (1) can be solved by making the distance between the outer portions of two shoulders facing each other with the material to be joined narrower than the distance between the pin side (inner) portions.

The above problems (2) and (3) can be solved by providing a cutting blade on both or either of the two shoulders sandwiching the material to be joined.

By narrowing the distance between the two shoulders at the outer portion and widening the inner portion of the pin base, a high pressure can be applied to the agitating metal at the joint portion during the jointing process, so that there is no defect in the joint portion. Is obtained.

By providing a cutting blade on both or either of the shoulders, it is possible to make a hole in the material to be welded even during the welding and to pull out the rotary tool from the material to be welded or to insert it again. Furthermore, even if the material to be joined has a locally thick portion, it is cut with a cutting blade before joining,
Since it can be joined with a constant thickness, the joining quality is also improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 shows a cross section of a rotary tool in an embodiment of the present invention. The rotary tool 1 includes two shoulders 3a provided so as to surround the thin pin 2.
(It is described as an upper shoulder) and 3b (is described as a lower shoulder). The pin 2 is threaded. Diameter of upper shoulder 3a (D1) and lower shoulder 3
The diameter (d2) of b is larger than the diameter (M) of the pin 2. Of the distance between the upper shoulder 3a and the lower shoulder 3b, the distance (H) at the outer portion and the distance (L) at the inner portion, which is the pin root, are determined by the thickness of the material to be joined. However,
Both intervals are smaller than the thickness of the material to be joined. When the distances (H) and (L) between the two shoulders are the same, the joining metal softened by friction stirring is extruded to the outside of the shoulder, resulting in insufficient filling, so that defects are likely to occur at the joint.
For this reason, in the rotary tool of the present invention, the interval (H) of the shoulder outer peripheral portion is made narrower than the interval (L) of the pin side portion. As a result, a high pressure is applied to the metal of the joint portion that has been frictionally stirred, so that a sound joint portion can be obtained. The intervals (H) and (L) are determined by the angle (α) formed by the pin side portion and the shoulder outer peripheral portion, and the angle (α) is 1 to
A range of 10 degrees is desirable.

FIG. 2 uses the rotating tool of the present invention to
The cross section at the time of joining a hollow material with a hollow inside is shown. The hollow material is made of an aluminum alloy, is composed of a face plate 5 and a plurality of ribs 6, and has a length of 20 m. here,
The thickness of the face plate 5 and ribs 6 of the hollow material is 2 mm.
The thickness of the joint is 5 mm, which is locally thicker than that of the face plate 5. This is because the joint part is cut by the shoulder during the joining process, so that the joint part is made thick in advance.

The pin diameter (M) of the rotary tool used for joining the hollow members is 7 mm, and the shoulder diameters (D1) and (D)
2) is 18 mm, the distance (H) between the outer parts of the two shoulders facing each other with the material to be bonded therebetween is 4 mm, and the distance (L) between the pin side parts is 3.5 mm. The rotary tool rotates in the direction indicated by arrow 4 in FIG.

[0013] As a result of using the rotating tool having the above-described shape and performing the welding at a welding speed of 500 mm / min and a rotating speed of the rotating tool of 1000 rpm, it was possible to perform welding without defects. Note that FIG. 2 shows a state in which the back side of the hollow material is joined by the rotary tool of the present invention to form the joined portion 7.
The hollow material manufactured according to the present embodiment is used for railway vehicles.

(Embodiment 2) FIG. 3 shows a sectional structure of a rotary tool in which a cutting blade is provided on the lower shoulder 3b side of two shoulders sandwiching a material to be joined. Lower shoulder 3b
The cutting blade 8 provided at the position effectively works when the rotary tool 1 is inserted into or removed from the material to be welded.

FIG. 4 shows a cross section of the arrangement of the material 9 to be welded and the rotary tool 1 after inserting the rotary tool 1 into the material 9 to be welded.
As shown in FIG. 4, the lower shoulder 3 on the back surface side of the material 9 to be joined
A hole 10 having a diameter slightly larger than the diameter (D2) of the lower shoulder is made in the material 9 to be joined by the cutting blade 8 provided at b. As a result, the rotary tool can be inserted into the materials to be joined even during the joining, so that the joining can be performed.

On the other hand, when the rotary tool 1 is pulled out in the process of joining before reaching the terminal end of the joining, a hole 10 slightly larger than the diameter (D2) of the lower shoulder is formed in the joined materials by the cutting blade, and the tool is rotated. The tool 1 can be pulled out from the material 9 to be joined.

The rotary tool provided with the cutting blade 8 allows the rotary tool to be inserted into or pulled out of the materials to be welded even during the welding, so that the welding work efficiency is improved.

(Embodiment 3) FIG. 5 shows a sectional structure of a rotary tool in which an upper shoulder 3a is provided with a cutting blade 8a and a lower shoulder 3b is provided with a cutting blade 8b. FIG. 6 shows a state in which the rotary tool having the structure shown in FIG. Similar to the second embodiment, the cutting blades 8a and 8b effectively act when the rotary tool 1 is inserted into the material to be welded and withdrawn from the material to be welded during the welding.

On the other hand, in this embodiment, the cutting blades 8a and 8a
b is also provided on the side surfaces of the upper and lower shoulders. The cutting blade on the side surface cuts the front surface and the back surface of the material to be bonded 9 to a constant thickness when there is a thick portion in the material to be bonded in the process of bonding. As a result, the thickness of the materials to be joined is constant before joining, and the frictional heat is also constant, and stable joining is possible. Further, since the load applied to the rotary tool can be reduced, the durability of the rotary tool can be improved.

[0020]

According to the present invention, the two shoulders facing each other with the pin interposed therebetween have a wide inner side and a narrow outer side, so that a high pressure is applied to the stirring metal in the joint portion during the jointing process. It is possible to reduce the occurrence of defects. Further, by providing the cutting blade on the shoulder, the rotary tool can be inserted into and pulled out from the materials to be welded even during the welding, thus improving work efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view of a rotary tool showing an embodiment of the present invention.

FIG. 2 is a sectional view showing an arrangement of a rotary tool and a material to be joined according to an embodiment of the present invention.

FIG. 3 is a sectional view of a rotary tool according to another embodiment of the present invention.

FIG. 4 is a sectional view showing an arrangement of a rotary tool and a material to be joined according to another embodiment of the present invention.

FIG. 5 is a sectional view of a rotary tool according to still another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an arrangement of a rotary tool and a material to be welded according to still another embodiment of the present invention.

[Explanation of symbols]

1 ... Rotating tool, 2 ... Pin, 3a ... Upper shoulder, 3b ...
Lower shoulder, 4 ... Rotating direction of rotating tool, 5 ... Face plate of hollow material, 6 ... Rib, 7 ... Joining portion, 8 ... Cutting blade, 9 ... Joined material, 10 ... Hole.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kinya Aota             7-1-1, Omika-cho, Hitachi-shi, Ibaraki Prefecture             Inside the Hitachi Research Laboratory, Hitachi Ltd. F-term (reference) 4E067 AA05 BG00 CA01 CA04 EC06

Claims (5)

[Claims] 1. A rotary tool for friction stir welding in which two shoulders thicker than the pins are provided so as to locally sandwich a thin pin, and in the rotary tool for friction stir welding, the distance between the two shoulders is closer to the outer peripheral side than to the pin side. Rotating tool for friction stir welding, characterized by narrowing. 2. A rotary tool for friction stir welding in which two shoulders thicker than the pins are provided so as to locally sandwich a thin pin, and a cutting blade is provided on at least one of the two shoulders. A rotary tool for friction stir welding. 3. The rotary tool for friction stir welding according to claim 1, wherein a cutting blade is provided on at least one of the two shoulders. 4. The rotary tool for friction stir welding according to claim 1 or 3, wherein an angle inclined from the pin root of the shoulder to the outer peripheral side is in the range of 1 to 10 degrees. 5. A friction stir welding method using the rotary tool according to claim 1, wherein a material to be welded is sandwiched between two opposing shoulders to perform welding. .