JP2002224860A - Butt welding method of metal by friction stir welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a butt welding method of aluminum alloy, copper alloy, etc., by friction stir welding in which any non-welded part is left behind. SOLUTION: In the butt welding method of a metal joining member using a friction stir welding method, a back side of a butted part 3 is brought into contact with a backing 8 of the same material as that of a joining member 1 and/or 2, a rotating tool 4 is inserted in the face side of the butted part, the inserted tool 4 is moved along the butted part 3 while softening and stirring the tool 4 and the butted part 3 by the friction heat, and the butted part 3 of the joining members 1 and 2 and the backing material 8 are simultaneously welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a metal, for example,
The present invention relates to butt joining of metal materials such as copper and copper alloys, and more particularly to a butt joining method by friction stir welding that does not generate an unjoined portion at a butt portion.

[0002]

2. Description of the Related Art In a conventional friction stir welding method, a rotating tool is inserted into a butt portion when butt-joining members, and a material near the butt portion heated by frictional heat between the tool and the member is butt-joined. In some cases, the solid-state joining is performed by moving the tool along the part and moving the tool relatively behind the tool (Japanese Patent Publication No. 7-505090 (FP06)).
15480B1)).

At this time, the members to be joined are supported by using a high-strength backing material such as a steel plate. In addition, the shape of the tool and the relative positional relationship between the tool and the joining member are important in order not to leave unjoined parts at the butted part.
Each time the shape of the joining member changes, it is necessary to optimize them based on empirical know-how.

For example, it is known to measure the relative distance between a tool using a laser displacement meter or the like and a joining member in order to prevent an unjoined portion from being left in butt joining of aluminum plates. As a method that does not leave an unbonded portion, Japanese Patent Application Laid-Open No. 10-22578
No. 0 discloses a method of providing a surplus portion on the back surface near the abutting portion. This relates to friction stir welding of an extruded material of a long aluminum alloy, in which a surplus portion is provided in advance in a step of forming a material, and an unjoined portion is suppressed.

[0005]

According to preliminary tests, the inventors have found that in the butt joining of aluminum plates using the friction stir welding method, every time the shape of the joining member changes, By performing a series of trial and error to optimize the tool shape and the relative distance between the tool and the joining member, we have confirmed that sound joining is possible.

However, in the butt joining of the copper plates by the friction stir welding method, a series of trial and error as described above was performed in order to leave no unjoined portions. It often occurred that the patch was also joined at the same time.

[0007] The maximum temperature of the joint in friction stir welding of aluminum is about 450 ° C, whereas that of copper is 8 ° C.
The temperature becomes higher than 00 ° C. If the length of the tool is increased so as not to leave unjoined parts, friction occurs between the tip of the tool, the agitated joint (copper) and the steel plate of the backing material, and the tool temperature rises significantly. Further, the joining member and the steel plate of the backing material were joined.

When the length of the tool is shortened, unjoined portions remain due to insufficient stirring, and the strength of the joined portions is reduced.

Examples of the application of such a butt joining method include:
For example, aluminum alloy, oxygen-free copper, or Sn, Z
There is an apparatus for producing a large-diameter coil for rolling made of a copper alloy containing a small amount of r, Cr or the like.

In general, a copper alloy thin plate for an electronic material is continuously rolled. In order to increase the efficiency of the rolling process, it is required that the material to be rolled be lengthened and provided as a large-diameter coil for rolling. In order to lengthen the coil, the winding end of the material to be rolled up by the coil and the unwinding end of the material to be rolled out from another coil are joined by MIG. However, since such conventional MIG welding is fusion welding, a change in the structure or composition of a joint due to heat occurs, and the joint may become brittle and break during rolling.

On the other hand, a joining method using friction stir welding is known in Japanese Patent Application Laid-Open No. Hei 10-230320, and in particular, the strength of the joined portion is reduced due to the remaining unjoined portion. It does not describe measures to prevent the adhesion between the steel backing material and the joint.

Further, as in the above-mentioned Japanese Patent Application Laid-Open No. Hei 10-225780, it is difficult to provide a surplus portion in advance from the material forming stage. The above-mentioned publication is particularly a technique relating to an extruded material of an aluminum alloy. In the case of an extruded material, it is easy to provide a convex portion in the material by providing a concave portion in an extrusion mold at a shape corresponding to a butt portion during molding. It is.

However, in the case of the above-mentioned rolling coil, it is difficult to apply a projection in a direction perpendicular to the rolling direction, which is difficult to apply. In this publication, the thickness of the excess portion is set to 0.05 to 0.33 times the thickness of the base material. For example, thickness 2.5m
In the case of a copper alloy having a thickness of 0.1 m, the excess thickness is 0.125 to 0.825.
mm.

In a preliminary test on the butt joining of copper alloys by the present inventors, the thickness in the above case is required to be 1 mm or more. Effective butt joining was not possible.

In the case of friction stir welding, the butted portion, including the excess portion, is supported by a strong backing material and must withstand the force received from the tool. Also, when clamping the material to the backing material whose shape matches the surplus part, if there is a slight gap between the material and the backing material, the material deforms and buckles due to the force received from the tool, and defects at the time of joining Occurs.

However, by providing a surplus portion in the material, the rigidity of the entire material is increased as compared with a flat plate. For this reason, when the material and the backing material were clamped, a small gap on the order of submicron was generated, and a slight defect was generated during bonding. For this reason, when the joined portion was cold-rolled after joining, a crack was generated from the slight joining defect as a starting point, and the joined portion opened (broken) during rolling.

An object of the present invention is to provide a butt-joining method by friction stir welding of an aluminum alloy, a copper alloy, or the like in which an unjoined portion does not remain in view of the above.

[0018]

The gist of the present invention to achieve the above object is as follows. In the butt joining method of the joining members using the friction stir welding method, the back side of the butt portion is brought into contact with a backing material made of the same material as the joining member, and a rotating tool is inserted into the front side of the butt portion, The tool is moved along the butt portion in an inserted state while softening and stirring the contact portion of the butt portion with frictional heat, and the butt portion of the joining member and the backing material are simultaneously joined. This is a joining method using friction stir welding.

After joining, the backing material of the same material as the joining member is removed by machining if necessary.

That is, as shown in a schematic perspective view showing an example of the joining method of the present invention shown in FIG.
When the rotating tool 4 is inserted and moved in the direction of the arrow 5 along the butting surface 3 where the tool 4 is joined, the joining members 1 and 2 form the joining portion 6 and are joined. At this time, the joining members 1 and 2 and the backing material 7 are clamped by a jig (not shown), and have a structure that can withstand the force received from the tool 4. Further, on the back surface near the butting portion 3,
A backing material 8 of the same quality as the joining members 1 and 2 is arranged.

FIG. 2 is a schematic sectional view showing the structure near the joint 6 after the above-described joining. Joining member 1 and / or
Alternatively, the backing material 8 formed of the same material as that of 2 is firmly joined by friction stir welding to form a joint 6. In this case, the tool shape by trial and error based on empirical know-how, the tool 4 and the joining members 1 and 2,
This eliminates the need for optimizing the relative distance between the two and for complicated control using a laser displacement meter.

[0022]

[Embodiment 1] This embodiment will be described with reference to the drawings. FIG. 3 is a schematic perspective view of a joining portion that joins two rolled materials wound around the coil in the apparatus for manufacturing a large diameter coil for rolling made of a copper alloy.

After joining, the rolled materials 9 and 10 move to the left in the drawing and are passed through a rolling mill (not shown) to be rolled. The material to be rolled 10 is wound around a coil (not shown). Since these materials 9 and 10 to be rolled are subjected to cold working after the friction stir welding, the joint 6 must be firmly joined. Next, a specific joining method will be described.

First, the end of the material 9 to be rolled and the material 10 to be rolled out of the coil are butted as shown in FIG. A backing material 8 made of the same material as the material to be rolled 9 and / or 10 is arranged below the butting surface 3. Also,
A steel backing material 7 is arranged around the periphery thereof, and these are clamped by a jig (not shown).

At this time, since the materials to be rolled 9 and 10 were flat and relatively low in rigidity, the gap between the materials to be rolled and the backing materials 7 and 8 during clamping was almost zero.

Next, when the rotating tool 4 is inserted into the butting surface 3 and then moved in the direction of arrow 5, a strong joint 6 is formed. In addition, since the joining start point and the ending point are different from the steady joining portion 6 in heat input conditions and the like, a starting tab and an ending tab (not shown) are provided and set at the positions.

Here, the materials 9 and 10 to be rolled have a sheet width of 50 mm.
× A strip having a thickness of 2.5 mm. The shape of the tool 4 used was 13 mm in diameter of the shoulder portion 11, the shape of the pin portion 12 was M8 screw, and the length was 2.3 mm or 2.6 mm.
The material is general tool steel. The rotation speed of the tool 4 was 1300 rpm, and the moving speed was 200 mm / min.

The shape of the backing material 8 is 2 mm thick.
The board width is slightly larger than the diameter of the pin 12 of the tool 4.
mm. By these methods, the joint 6 was formed over the rolled materials 9 and 10 and the backing material 8.

[Embodiment 2] In this embodiment, the material of the backing material 8 in FIG.
For a steel plate integrated with the backing material 7 and for general MIG welding, a large diameter coil of a copper alloy was manufactured and subjected to a rolling test to investigate the soundness of the joint after rolling.

The material to be rolled joined according to the present invention was subjected to rolling after the backing material joined together was removed by a grinder. The rolling test was performed in one pass to a rolling reduction of 60% using a cold rolling mill. Table 1 shows the soundness of the joint after rolling.

[0031]

[Table 1]

The rate of occurrence of cracks at the joints by rolling is indicated by a defective rate (%). According to the present invention, no crack was observed after rolling in any case. On the other hand, in the case of the conventional friction stir welding method, the remaining of the unwelded portion cannot be completely prevented, and in some cases, the side surface of the material to be rolled may open during rolling or may break at the joined portion. Yes, defect rate is 3
0%, which was higher than in the case of MIG welding.

[0033]

According to the present invention, a joined member can be produced by friction stir welding without leaving an unjoined portion, and the occurrence of cracks and the like in the subsequent rolling can be completely suppressed.

Further, it is not necessary to form a convex surplus portion in the material to be joined in advance, and it is only necessary to use a backing material of the same quality as the member to be joined each time, and from the viewpoint of productivity and cost. Is also an excellent method.

[Brief description of the drawings]

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

FIG. 2 is a schematic cross-sectional view of the vicinity of a joint after the joining in FIG.

FIG. 3 is a schematic perspective view of a joining portion for joining a material to be rolled in Example 1.

[Explanation of symbols]

1, 2, ... joining member, 3 ... butting surface, 4 ... tool, 5 ... moving direction, 6 ... joining portion, 7, 8 ... backing material, 9, 10 ... rolled material, 11 ... shoulder, 12 ... pin.

Continued on the front page (72) Inventor Masayuki Doi 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Satoshi Hirano 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Hisanobu Okamura 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Yasuhisa Aono Omikamachi, Hitachi City, Ibaraki Prefecture No. 1-1, Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Manabu Kagawa 3550 Kida Yomachi, Tsuchiura-shi, Ibaraki Hitachi Cable, Ltd. Tsuchiura Plant F-term (reference) 4E067 AA07 BG00 DD02

Claims (3)

[Claims] In a butt joining method of a metal joining member using a friction stir welding method, a back side of the butt portion is brought into contact with a backing material of the same material as the joining member, and a backing material of the butt portion is provided. Inserting the rotating tool on the opposite side, and moving the inserted tool along the butted portion while softening and agitating the tool and the butted portion by frictional heat, thereby joining the butted portion of the joining member and the backing material. Butt welding of metals by friction stir welding. 2. A butt-joining method for a metal joining member using a friction stir welding method, wherein the joining member is copper or a copper alloy, and a back side of the butt portion is made of a backing material made of a metal of the same material as the joining member. The tool is brought into contact, and a rotating tool is inserted into the opposite side of the butt portion where the backing material is provided, and the inserted tool is moved along the butt portion while the tool and the butt portion are softened and agitated by frictional heat. A butt joining method for metal by friction stir welding, wherein the butt portion of the joining member and the backing material are simultaneously joined by being moved. 3. The method according to claim 1, wherein the backing material is removed by machining after the joining of the butted portions.