JP2002248582A - Friction stir welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction stir welding method which makes materials to be joined undergo friction stir welding after a gap between the materials to be joined is filled for partial integration by a melt welding method or the friction stir welding method by means of a rotating tool and prevents a crack defect from occurring due to the gap between the materials to be joined. SOLUTION: In the friction stir welding method, the rotating tool, which is firmer in material properties than the materials 1a and 1b to be joined, is inserted with rotation between the materials 1a and 1b to be joined, which are joined together along a join line 4 by frictional heat and plastic flow. This method is characterized as follows: dummy materials 2a and 2b are disposed in a start part of joining and a terminal part thereof; the materials 1a and 1b and the dummy materials 2a and 2b are joined partially in advance by the melt welding method or the friction stir welding method; and after that, the joining is started from one of the dummy materials 2a and 2b, and terminated at the other one of the dummy materials 2a and 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel friction stir welding method, and more particularly to a friction stir welding method for preventing a joining defect occurring at a start portion and an end portion of a joint portion and improving the quality of the joint portion.

[0002]

2. Description of the Related Art A metal rod (hereinafter, referred to as a rotary tool) of a material substantially harder than a material of a material to be joined is inserted into a joint of the material to be joined, and the rotating tool is moved while rotating. Thus, a friction stir welding method for joining by frictional heat generated between the rotary tool and the material to be joined and plastic flow is disclosed in Japanese Patent No. 2712838 (WO9).
3/10935). In this friction stir welding method, the material to be welded is softened by frictional heat between the rotating tool and the material to be welded, and the plastic flow phenomenon accompanying the rotation of the rotating tool is used. It is based on a principle different from the welding method and the like.

[0003] As an apparatus for performing the friction stir welding method, for example, Japanese Patent Application Laid-Open Nos. 10-249552 and 10-180467 are known. JP Hei 10
Japanese Patent Laid-Open No. 249552 is directed to joining a flat member, and Japanese Patent Application Laid-Open No. 10-180467 is directed to joining a cylindrical member.

That is, in the friction stir welding method, frictional heat and plastic flow are generated between a workpiece and a workpiece by rotation and movement of a rotary tool (metal rod) made of a material harder than the workpiece, and the workpiece is joined to a welding line. It is a method of joining along the direction. This joining method has the features that the temperature of the joining portion is low, the distortion of the joining material is small, and the surface of the joining material is beautiful.
There are the following problems.

[0005]

A defect peculiar to the friction stir welding method occurs in the joints joined by the conventional friction stir welding method, particularly near the start portion and at the end. In particular, the end portion of the joint is likely to occur significantly. For this reason, a method is adopted in which a dummy material is arranged at the start and end portions of the material to be joined, joining is started from the dummy material portion and ends at the dummy material portion. However, if a gap (gap) exists between the material to be joined and the dummy material, the gap causes a crack defect near the gap of the material to be joined. This defect extends to the inside of the material to be joined and deteriorates the quality of the material to be joined.

On the other hand, when a plurality of materials to be joined are continuously joined in a joining line direction, crack defects occur in the materials to be joined due to a gap between the materials to be joined.

An object of the present invention is to provide a friction stir welding method for preventing the occurrence of crack defects caused by a gap between materials to be joined.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a gap between a workpiece and a workpiece is filled by a fusion welding method or a friction stir welding method using a rotary tool, and the gap is partially integrated. The materials are friction stir welded to each other. For this reason, friction stir welding can be performed at the friction stir welded portion without generating crack defects caused by a gap.

That is, the present invention provides a friction stirrer in which a rotating tool, which is harder than the material of a material to be joined, is inserted into the material to be joined while being joined together by friction heat and plastic flow along a joining line. In the joining method, a dummy material is arranged at a start portion and an end portion of the joint, and the joined material and the dummy material are joined in advance by a fusion welding method or a friction stir joining method, and then joining is started from one of the dummy materials. The bonding is completed with the other dummy material.

According to the present invention, a joining defect is locally caused by a fusion welding method or a friction stir welding before the entire joining line is joined between the joined material and the dummy material or the joined material by the friction stir welding. After joining, it can be prevented by friction stir welding. As the fusion welding method, an arc welding method is desirable, and in particular, a TIG welding method or a MIG welding is desirable.

On the other hand, a welding defect is inserted to a predetermined depth between a workpiece and a dummy or between a plurality of workpieces and a workpiece while rotating a rotary tool used for friction stir welding before friction stir welding. , Then pull out the rotation tool. Thereby, the material to be joined and the dummy material or the material to be joined and the material to be joined are locally joined. Next, it can be prevented by joining by a friction stir welding method. This object can be achieved by using a tool having the same shape as the rotating tool.

A joining defect is generated due to the presence of a gap between the material to be joined and the dummy or the material to be joined and the material to be joined.
Therefore, in the present invention, defects are prevented by eliminating or minimizing the gap before friction stir welding. The gap can be filled by a fusion welding method. That is, the gap can be filled by partially melting the material to be joined and the dummy material or the material to be joined and the material to be joined by the fusion welding method. On the other hand, the gap can be filled by inserting the rotating tool to a predetermined depth while rotating the tool, and then pulling out the same. In this case, no or slight movement of the rotating tool or the workpiece in the joining line direction is desirable.

[0013] The present invention relates to a friction stir welding method in which a rotating tool harder than the material of the material to be joined is inserted into the material to be joined while rotating, and the materials to be joined are joined along the joining line by frictional heat and plastic flow. After placing the dummy material at the start and end of the joining, joining the material to be joined and the dummy material in advance by a fusion welding method or a friction stir welding method, starting the joining from one dummy material and the other It is characterized in that the joining is completed with the dummy material.

According to the present invention, in the above-described friction stir welding method, a dummy material is arranged at a start portion and an end portion of the welding, and the material to be welded and the dummy material are brought to a predetermined depth with the rotating tool being rotated in advance. Inserting and then pulling out without rotating in the direction of the joining line while rotating the rotating tool to locally join the workpiece and the dummy material, then start joining from one dummy material and the other dummy material To terminate the joining.

The present invention is characterized in that, in the above-described friction stir welding method, the materials to be joined are locally welded in advance by a fusion welding method or locally joined by a friction stir welding method, and then friction stir welding is performed. I do.

According to the present invention, there is provided a friction stir welding method in which a plurality of joining lines are formed, and the divided workpieces are continuously joined along the plurality of joining lines. Is characterized in that friction stir welding is locally performed by welding or friction stir welding locally, and then friction stir welding is continuously performed along a plurality of welding lines.

According to the present invention, in the friction stir welding method for continuously joining along a plurality of joining lines described above, a plurality of joining lines are inserted to a predetermined depth while rotating the rotating tool in advance, and It is characterized in that, after rotating the rotating tool and pulling it out without moving in the direction of the welding line, welding is performed locally, and then friction stir welding is continuously performed along a plurality of welding lines.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG.
Material 1a and Material 1b consisting of aluminum alloy plate of JIS standard 5083 m, length 500mm, each width 100mm
FIG. 4 is a perspective view showing a state before joining when joining by a friction stir welding method. In this friction stir welding method, the material to be welded 1 is rotated while rotating a rotary tool harder than the material of the material to be welded.
Inserted into a and 1b to join the materials to be joined by friction stir welding along the joint line by frictional heat and plastic flow. Since defects tend to occur at the start and end of the joint, Dummy materials 2a, 2b of the same material as the materials to be joined 1a, 1b are arranged at the part and the terminal end, and as shown in FIG.
The start portion and the end portion of a and 1b are locally joined by arc welding to a predetermined length in a direction intersecting the joining line between the workpieces 1a and 1b.

However, even when the dummy materials are arranged and joined, if there is a gap between the materials to be joined 1a, 1b and the dummy materials 2a, 2b, crack defects also occur in the materials to be joined. Particularly when the gap between the workpieces 1a and 1b and the dummy workpieces 2a and 2b is large, the problem occurs remarkably. Therefore, in this embodiment, the materials 1a and 1b and the dummy materials 2a and 2b are joined before the friction stir welding.
Welds 3a and 3b by welding locally between
Are formed and the gap is filled to unite the two. As shown in FIG. 2, the workpieces 1a and 1b in which the gaps are filled are rubbed from the vicinity of the center of the dummy material 2a to the vicinity of the center of the dummy material 2b along the bonding line 4 in FIG. Stir welding.

It should be noted that arc welding is also effective with TIG welding or MIG welding. In the case of TIG welding, if the gap is large, adding a wire and welding is more effective. The arc welding in the present example employed a TIG welding method, and was performed by adding a welding wire. The welding width is 20 mm, which is slightly larger than the shoulder diameter (15 mm) of the rotary tool 5 used in this embodiment. The speed of friction stir welding is 500mm / mi
n, the rotation speed of the rotating tool is 1000 rpm. No crack defects are found in the gaps 6a and 6b between the materials 1a and 1b and the dummy materials 2a and 2b joined in the above embodiment. When the gap is 0.5 mm or less, the gap is filled even when the rotary tool is rotated and inserted to the shoulder position and pulled out without moving the rotary tool.

(Embodiment 2) FIG. 3 shows that the thickness is 5 mm and the length is 3 mm.
00mm, 100mm width JIS 5052 aluminum alloy plate
It is a perspective view which shows the state before joining in the case of carrying out friction stir welding of six pieces of 1a-1f continuously in the direction of three several joining lines. As shown in the figure, the distance between the workpieces 1a to 1f is 0.2 m.
Since there is a gap of m to 1 mm, all the workpieces 1a to 1f have a predetermined length in the direction intersecting the joining line by MIG welding before the friction stir welding, as in the first embodiment. Are welded 3a so that
And 3b. The material to be joined whose gap is filled by welding at two places is continuously friction stir welded along the three joining lines 4 in the joining line direction 4 by rotating and moving the rotary tool 5 as shown in FIG. . In addition, arc welding part 3
The lengths of a and 3b are 20 mm, which is slightly larger than the shoulder diameter (15 mm) of the rotary tool used in this embodiment. The welding speed of the friction stir welding is 500 mm / min, and the rotation speed of the rotating tool is 1000 rpm.

In this embodiment, a sound bonded body in which no crack defect is observed at the joints 6a and 6b between the materials to be welded and the materials to be welded subjected to friction stir welding is obtained.

(Embodiment 3) FIG. 5 shows a thickness of 3 mm and a length of 300
FIG. 3 is a perspective view showing a state before joining when three pipes 1a, 1b, 1c of an aluminum alloy of JIS standard 5083 having an outer diameter of 300 mm and 300 mm are continuously friction stir welded in three joining lines 4 directions. is there. The dummy material 2a and the dummy material 2b in FIG. 5 are dummy pipes arranged at the start and end of the joining pipe. 0.2mm to 1m between pipes for joining
m, there is a gap between the gaps beforehand.
Four welds 3a to 3 in the same manner as in Example 1 by the G welding method
Form d to fill the gap. The arc welding in the present example adopted the TIG welding method and performed welding without adding a welding wire. After welding, as shown in FIG. 6, the pipe is continuously friction stir welded in the direction of the joining line 4 by frictional heat and plastic flow caused by rotation and movement of the rotary tool 5. Where TIG
The length of the welds 3a to 3d is 15 m, which is slightly larger than the shoulder diameter (12 mm) of the rotary tool used in this embodiment.
In the friction stir welding, the speed is 500 mm / min, and the rotation speed of the rotating tool is 1000 rpm. Note that a metal rod having a diameter slightly smaller than the inner diameter of the pipe is inserted into the pipe in order to prevent deformation of the pipe due to the pressing force of the rotating tool.

Since there is no gap in the joints 6a to 6d between the pipes joined in the above embodiment, no crack is generated, and no crack is generated. The pipe joined by the joining was processed into a wheel for an automobile.

When the gap is 0.5 mm or less, the gap is filled even if the rotary tool is rotated and inserted to the shoulder position and pulled out without moving the rotary tool. In actual joining, starting from the center of the dummy material 2a of the dummy pipes arranged at the start and end portions, the joining is performed at the center of the dummy material 2b.

(Embodiment 4) FIG. 7 shows a thickness of 3 mm and a length of 300 mm.
FIG. 4 is a perspective view showing a state before joining when two pipes 1a and 1b of an aluminum alloy of JIS standard 5083 having an outer diameter of 300 mm and JIS standard 5083 are continuously friction stir welded in two joining line 4 directions. The gap between the joining pipes 1a and 1b in FIG.
There is a gap of 2 mm to 1 mm. FIG. 8 is a sectional view showing the shape of the rotary tool 5 used in the present embodiment. The rotating tool 5 includes a pin 8 having a thin tip and a thick shoulder 9. The pin diameter is 5 mm and the shoulder diameter is 13 mm. As shown in FIG. 7, when the rotating tool 5 is rotated at three positions, the shoulder 9 slightly extends between the workpiece and the dummy workpiece and between the workpieces and the workpiece. Insert until it enters. Thereafter, the rotating tool 5 is immediately pulled out. At this time, the rotating tool 5 and the material to be joined do not move in the joining line 4 direction. This operation eliminates gaps between the material to be joined and the dummy plate and between the material to be joined and the material to be joined, and enables local joining.

Next, as shown in FIG. 9, the pipes 1a and 1b are caused by frictional heat and plastic flow caused by rotation and movement of the rotary tool 5.
Are continuously friction stir welded in the direction of the welding line 4. here,
Joining starts at the dummy plate and ends at the dummy plate. The speed of the friction stir welding is 500 mm / min, and the rotation speed of the rotating tool is 1000 rpm. Note that a metal rod 7 having a diameter slightly smaller than the inner diameter of the pipe is inserted into the pipe in order to prevent deformation of the pipe due to the pressing force of the rotating tool.

Since there is no gap in the joints 6a to 6b between the pipes joined in the above embodiment, no crack defect occurs in the joint after friction stirring. The pipe joined by the joining was processed into a wheel for an automobile.

[0029]

According to the present invention, after the gap between the materials to be joined is filled and integrated by fusion welding or friction stir welding by rotation of a rotating tool, the materials to be joined are friction stir-bonded. Because of the joining, the occurrence of crack defects caused by the gap is prevented in the friction stir welding portion.
Therefore, sound friction stir welding can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention before friction stir welding.

FIG. 2 is a perspective view after friction stir welding, showing Example 1 of the present invention.

FIG. 3 is a perspective view showing a second embodiment of the present invention before friction stir welding.

FIG. 4 is a perspective view after friction stir welding, showing Example 2 of the present invention.

FIG. 5 is a perspective view showing a third embodiment of the present invention before friction stir welding.

FIG. 6 is a perspective view after friction stir welding showing Example 3 of the present invention.

FIG. 7 is a perspective view showing a fourth embodiment of the present invention before friction stir welding.

FIG. 8 is a sectional view of a rotary tool according to a fourth embodiment of the present invention.

FIG. 9 is a perspective view after friction stir welding showing Example 4 of the present invention.

[Explanation of symbols]

1a, 1b, 1c, 1d, 1e, 1f: Material to be joined, 2a, 2b: Dummy material, 3a, 3b: Welded part 3a, 3b, 4: Joint wire, 5: Rotary tool, 6a, 6b: Gap part, 7 ... metal rod.

Claims (6)

[Claims] In a friction stir welding method, a rotating tool, which is harder than a material of a material to be joined, is inserted into the material to be joined while rotating, and the materials to be joined are joined along a joining line. A friction stir welding method, which comprises partially welding by a fusion welding method or partially joining by a friction stir welding method, and then performing the friction stir welding. 2. A friction stir welding method in which a rotating tool harder than the material of a material to be joined is inserted into the material to be joined while rotating, and the materials to be joined are joined along a joining line. A friction stir welding method, wherein the end portion is partially welded in advance by a fusion welding method, or after the partial joining by a friction stir welding method, and then joined along the joining line. 3. A friction stir welding method in which a rotating tool that is harder than the material of the material to be joined is inserted into the material to be joined while rotating, and the materials to be joined are joined along a joining line. After the dummy material is arranged at the end portion and after the material to be joined and the dummy material are partially welded in advance by a fusion welding method or after the partial joining by a friction stir welding method, one of the dummy materials A friction stir welding method, wherein the welding is started from a material, and the welding is ended with the other dummy material. 4. A friction stir welding method in which a rotating tool harder than the material of the material to be joined is inserted into the material to be joined while rotating, and the materials to be joined are joined along a joining line. A dummy material is arranged at the end portion, and the material to be joined and the dummy material are inserted to a predetermined depth while rotating the rotating tool in advance, and then moving in the joining line direction while rotating the rotating tool. After partially joining the material to be joined and the dummy material by pulling out without,
A friction stir welding method, wherein the joining is started from one of the dummy materials, and the joining is ended with the other dummy material. 5. A friction stir welding method in which a plurality of joining lines formed with a plurality of joining lines are continuously joined to each other along the plurality of joining lines. And then performing the friction stir welding continuously along the plurality of welding lines after the partial friction stir welding is performed by the partial welding or the friction stir welding method. 6. A friction stir welding method in which a plurality of joining lines formed with a plurality of joining lines are continuously joined to each other along the plurality of joining lines. After inserting the tool to a predetermined depth in a rotated state, and then partially joining by rotating the rotating tool and pulling it out without moving in the joining line direction,
A friction stir welding method, wherein the friction stir welding is continuously performed along the plurality of welding lines.