JP2006312198A - Friction stir joining method, and friction stir joined body joined by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction stir joining method where a joint in which a gap is formed can be supplemented by simple treatment, and to provide a friction stir joined body joined by the method. <P>SOLUTION: In the friction stir joining method, a stirring axis 52 in a rotating joining tool 50 is inserted into a joint obtained by butting a pair of the members 21, 22 to be joined, the joining tool 50 is relatively moved to the members 21, 22 to be joined along a joining line 20 in which the joint is continued, and, as the joint is softened by the generated friction heat, the same is stirred and kneaded, so as to join the members to be joined, the stirring axis 52 in the rotated joining tool is inserted into the joint, and is relatively moved along the welding line, as a beltlike plate 10 flat in the upper and lower sides is superimposed to the members 21, 22 to be joined along the joining line 20, and the stirring axis 52 in the rotated joining tool is inserted into the joint, and is relatively moved along the joining line, thus, as the members 21, 22 to be joined and the beltlike plate 10 are simultaneously softened by the friction heat generated at the joint, the same is stirred and kneaded, so as to be joined. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a friction stir welding method for joining a pair of members to be joined by plastic fluidization by friction heat and pressure, and a friction stir joined body joined by the method. The present invention relates to a friction stir welding method capable of greatly affecting quality, and in particular, even when gaps are irregularly present in a joint, and capable of filling the gaps by a simple process, and a friction stir joined body joined by the method.

  In recent years, various friction stir welding methods have been proposed as new joining methods in place of welding and brazing of metal materials.For example, the friction stir welding method can be used for joining long extruded mold members constituting a railway vehicle structure. It is being advanced. Since such friction stir welding can be performed at a lower temperature than fusion welding or brazing, there is an advantage that there is little bonding failure due to thermal deformation at the time of bonding or oxidation of the bonded portion, and it is suitable for bonding long extruded mold materials. .

  Here, FIG. 4 is a diagram showing an outline of the friction stir welding method. In this friction stir welding, as shown in the drawing, the bonding surfaces of a pair of bonded plates 21 and 22 are abutted as bonded members. A friction stir welding tool 50 for performing friction stir welding is obtained by projecting a stirrer shaft (probe) 52 made of a material harder than the plates 21 and 22 to be joined to a rotating body 51. And in order to join to-be-joined plates 21 and 22, the rotary body 51 is rotated at high speed, and the probe 52 is inserted along the joining line 20 with which the joined part which faced | matched continues. At that time, the friction stir welding tool 50 is moved relative to the plates 21 and 22 to perform solid phase bonding in which the material is plastically flowed by the probe 52.

By the way, in this friction stir welding, when the gap between the joined plates 21 and 22 which are the joined members that are abutted becomes large, good joining cannot be performed. Therefore, the following methods have been proposed for friction stir welding.
For example, in the method proposed in Japanese Patent Application Laid-Open No. 2004-261859, a joining groove between joined members formed by cutting the abutting surface (joined portion) of the joined members with a uniform width. A filling material is inserted into the case. This filling material is a band-shaped material along the abutting portion, and has a T-shaped cross section so that it can be easily restrained when inserted in the joining groove. Then, the filling material is pushed into the groove by a roller, and the friction stir welding tool performs the friction stir welding with the inserted filling material as a center to form a friction stir welding portion.

In addition, Japanese Patent Laid-Open No. 2002-210571 proposes the following method. The members to be joined are abutted so that the gap between the joints is as small as possible, and the abutting surfaces of the restrained members to be constrained are cut from above with a cutting tool to form a groove having a certain width in the joint. A filling material is disposed in the groove, the convex portion near the groove is pressed from above and the corner is bent toward the groove side, and the filling material is pressed and fixed to the member to be joined. By doing so, the filling material does not move during the friction stir welding. Then, the friction stir tool is inserted into the abutting portion from above, and the three members, the member to be joined and the filling material, are friction stir welded.
JP 2004-261859 A (5th page, FIG. 5) Japanese Patent Laying-Open No. 2002-210571 (page 5-6, FIG. 1)

  However, in the conventional method, cutting is applied to the joined portion where the members to be joined are abutted, and a supplementary material is put into the formed groove, which takes time and increases the processing cost. I was sorry. For example, when considering the case where friction stir welding is performed on an extrusion mold material constituting a railway vehicle structure, the joint portion between the members to be joined is as long as 20 m. In such a case, cutting is a very labor-intensive operation, and since the cutting groove must be filled with a filling material, both the groove side and the filling material side have a considerable degree of machining accuracy. It will be required and the cost will be further increased. And no matter how much the processing accuracy is increased, it is difficult to order the filling material in a groove having a slight width over several meters, and it is considered difficult in practice.

  Therefore, in order to solve such problems, the present invention aims to provide a friction stir welding method capable of supplementing a joint where a gap is generated by a simpler process and a friction stir joined body joined by the method. To do.

  The friction stir welding method according to the present invention inserts a stirring shaft of a rotated welding tool into a joint portion where a pair of members to be joined is abutted, and joins the joined members along a joining line where the joint portions are continuous. The tool is moved relatively, and the joined parts are joined by agitating and kneading while softening the joined portion by the generated frictional heat, and the members to be joined are joined to each other. By inserting the stirring shaft of the welding tool that is overlapped and rotated along the joint and moving it relatively along the joint line, the member to be joined and the belt-like plate are simultaneously moved by the frictional heat generated in the joint. It is characterized by being stirred and kneaded while being softened.

Further, in the friction stir welding method according to the present invention, prior to the insertion of the welding tool, the belt-like plate superimposed on the joining line of the member to be joined is welded to the member to be joined by welding or friction stir welding. It is preferable to temporarily fix several places in the longitudinal direction.
In the friction stir welding method according to the present invention, it is preferable that the belt-like plate has a thickness that is larger than the gap between the joining lines where the members to be joined are brought into contact with each other.

Further, in the friction stir welding method according to the present invention, it is preferable that the joining tool has a stirring shaft protruding from an end face of a rotating body, and the end face of the rotating body is pressed against the belt-like plate to perform friction stir welding. .
Further, in the friction stir welding method according to the present invention, the lower rotary body is integrally formed on the stirring shaft provided by protruding the projecting tool from the end face of the rotary body. Friction stir welding is preferably performed by sandwiching the member and the belt-like plate.

On the other hand, in the friction stir bonded body according to the present invention, a pair of members to be joined are abutted and a stirring shaft of a welding tool rotated at the joint is inserted, and along the joining line where the joint is continuous with the member to be joined. When the welding tool is relatively moved, the joining portion is softened by the frictional heat generated and agitated and kneaded to form a joint, and a strip-like plate that is flat with respect to the members to be joined is formed. The agitating shaft of the joining tool that is superposed along the joining line and rotated in that state is inserted into the joining part and relatively moved along the joining line, so that the members to be joined are caused by frictional heat generated at the joining part. And the belt-like plate are simultaneously softened, agitated and kneaded and joined.
In the friction stir bonded body according to the present invention, the member to be bonded is an extruded hollow mold material.

Therefore, according to the present invention, it is only necessary to superimpose the belt-like plate on the joining line where the joined portions of the joined members to be joined are continuous. For example, the joining portion is cut or processed as in the past. Since the filling material is not loaded in the groove, the friction stir welding can be performed by filling the gap between the joints by a simple process. And a joining part can be joined reliably and the friction stir joined body which ensured watertightness and airtightness can be provided.
In addition, conventionally, a processing machine for forming a groove for a joint and forming a filling material is required, and an operation for that purpose is also required. However, in the present invention, special processing is performed only by preparing a belt-like plate. The friction stir welding can be simplified and the processing cost can be reduced.

  Next, an embodiment of the friction stir welding method according to the present invention and the friction stir joined body joined by the method will be described below with reference to the drawings. FIG. 1 is a diagram conceptually illustrating the friction stir welding method according to the first embodiment. In this friction stir welding method, a stirrer shaft of a friction stir welding tool is inserted into a joint part where the plates 21 and 22 to be joined, which are a pair of members to be joined, are joined, and the joining part is continuous along the joining line 20. When moving relatively while rotating, joining is performed by stirring while plastically fluidizing by the generated frictional heat and pressure.

  The friction stir welding tool 50 includes, for example, a columnar rotating body 51 coupled with a driving unit of a rotation driving device (not shown), and a cylindrical stirring shaft (hereinafter referred to as a “probe”) protruding coaxially on an end surface thereof. 52) is formed integrally. The probe 52 is formed from the center of the end face of the rotator 51 to a length corresponding to the thickness of the joined portion of the member to be joined. In order to efficiently stir the material, the probe 52 is threaded, and various other processes are applied to the end face of the rotating body 51.

  In the joined plates 21 and 22, there are portions where the abutted end faces are not abutted against each other and a gap 23 is generated. In this embodiment, when the joined portions of the plates 21 and 22 are thus viewed along the continuous joining line 20, not only the butted portions but also the portions having gaps 23 are left as they are. The belt-like plate 10 was overlapped as a filling material. The belt-like plate 10 is formed so that the plate thickness dimension is larger than the maximum width of the gap 23 generated between the joined plates 21 and 22, and is made of the same material as the joined plates 21 and 22. Is. The joint portions are continuously arranged on the joining line 20 or arranged separately. However, if the friction stir welding is performed in this state, the belt-like plate 10 may be displaced from the joining line 20 during construction. Therefore, the belt-like plate 10 is welded to the plates 21 and 22 in advance, or the friction stir welding is performed. Attach multiple locations.

  Therefore, after the belt-like plate 10 is overlapped on the butted plates 21 and 22 that are abutted, the rotating body 51 and the probe 52 protruding from the tip thereof are given high-speed rotation by a rotation driving unit (not shown), and the probe 52 is It is pressed against the butted portions of the two butted plates 21 and 22 that have been butted and inserted. At this time, the end surface of the rotating body 51 on which the probe 52 protrudes is pressed so as to pressurize the upper surface of the belt-like plate 10.

  The friction stir welding tool 50 moves relatively along the joining line 20 of the plates 21 and 22 to be joined, and the joining portion between the belt-like plate 10 and the plates 21 and 22 that are plastically fluidized is the advance pressure of the probe 52. Then, the mixture is agitated and kneaded and plastically flows around the friction stir welding tool 50, and then rapidly loses the frictional heat to be cooled and solidified. At this time, even when a gap 23 is generated between the plates to be joined 21 and 22, the belt-like plate 10 as a filling material is agitated and kneaded so that the gap 23 is filled.

Therefore, according to the friction stir welding method of the present embodiment, the friction stir welding can be performed by filling the gap 23 of the joint portion by a simple operation only by superimposing the belt-like plate 10 on the joint portions of the butted plates 21 and 22 that have been joined. It became possible to do. That is, unlike the conventional method, friction stir welding in which the gap 23 is easily filled can be performed without performing a time-consuming process of loading a filling material into a groove formed by cutting the joint. It was. And a joined part can be joined reliably and the friction stir joined body which ensured watertightness and airtightness came to be able to be provided.
Further, in the conventional method, a processing machine for forming a groove and a filling material for the joint portion is necessary, and the work for that is also necessary. However, in the friction stir welding method of the present embodiment, the belt-like plate 10 is attached. There is no need to perform special processing just by preparing it, and friction stir welding can be simplified, thus reducing processing costs.

  Next, the friction stir welding method of the present invention and the friction stir joined body joined by the method are effective not only for joining the plates 21 and 22 to be joined as described above but also for joining between other members to be joined. . In a railway vehicle or the like, the vehicle structure is composed of an extruded hollow mold material, which is also effective for joining such extruded hollow mold materials. FIG. 2 is a view conceptually showing the friction stir welding method of the second embodiment for joining extruded hollow mold members.

  The extruded hollow mold materials 31 and 32 are aluminum mold materials formed by extrusion molding, and are long and have a predetermined width in the lateral direction of the drawing and a longitudinal direction of about 20 m. The cross-section of the extruded hollow mold members 31 and 32 as viewed in the longitudinal direction has a truss structure in which the upper surface plate 35 and the lower surface plate 36 are connected by a plurality of inclined surface plates 37. Among them, the lower surface plate 36 is protruded in the width direction, and friction stir welding is performed at a joint portion where the lower surface plates 36 are abutted with each other. In the present embodiment, only the lower surface plate 36 is abutted, but the upper surface plate 35 may be abutted on both sides.

  In the extruded hollow mold members 31 and 32, there are places where the end surfaces of the abutted lower surface plates 36 are not butted against each other and a gap 33 is generated. Also in this embodiment, when the joint portion of the lower surface plates 36 and 36 is viewed along the continuous joining line 30, not only the butted portion but also the portion where the gap 33 is vacant is left as it is. The belt-like plate 11 was overlapped as a filling material. The belt-like plate 11 is formed so that the plate thickness dimension is larger than the maximum width of the gap 33 formed between the lower surface plates 36, 36, and is formed of the same material as the extruded hollow mold materials 31, 32. It is.

  The belt-like plate 11 is continuously arranged on the joining line 30 where the joining portions are continuous, or is divided and arranged. However, if the friction stir welding is performed in this state, the belt-like plate 11 is displaced from the joining line 30 during the construction. Therefore, the belt-like plate 11 is previously welded to the lower surface plates 36 and 36, or a plurality of locations are obtained by friction stir welding. Install it. After the belt-like plates 11 are superposed in this way, a high-speed rotation is given to the rotating body 51 and the probe 52 projecting from the tip of the rotating body 51 by a rotation driving unit (not shown). It is inserted so as to press against the butt. At this time, the end surface of the rotating body 51 on which the probe 52 protrudes is pressed so as to pressurize the upper surface of the belt-like plate 11.

  The friction stir welding tool 50 moves relatively along the joining line 30 of the lower surface plates 36, 36, and the joined portion of the plastically fluidized belt-like plate 11 and the lower surface plates 36, 36 receives the advancing pressure of the probe 52. After stirring and kneading and plastically flowing so as to go around the friction stir welding tool 50, the frictional heat is rapidly lost to solidify by cooling and joining. At this time, even when the gap 33 is generated between the abutted lower surface plates 36, 36, the band-like plate 11 as the filling material is agitated and kneaded so that the gap 33 is filled.

Therefore, according to the friction stir welding method of this embodiment, the friction stir welding in which the gap 33 of the joint portion is filled by a simple operation only by superimposing the belt-like plate 11 on the joint portion of the extruded hollow mold members 31 and 32 that are butted together. It became possible to do. That is, as in the conventional method, it is possible to easily perform friction stir welding in which the gap 33 is filled without performing a time-consuming process of loading a filling material into a groove formed by cutting the joint. It was. And a joined part can be joined reliably and the friction stir joined body which ensured watertightness and airtightness came to be able to be provided.
Further, in the conventional method, a processing machine for forming a groove processing and a filling material for the joint portion is necessary, and the work for that is also necessary. However, in the friction stir welding method of the present embodiment, the belt-like plate 11 is attached. There is no need to perform special processing just by preparing it, and friction stir welding can be simplified, thus reducing processing costs.

  Next, the friction stir welding method of the present invention and the friction stir joined body joined by the method are the same as the friction stir welding tool 50 for joining the same plates 21 and 22 or the extruded hollow mold members 31 and 32. Can use different tools. That is, the friction stir welding tool 50 shown in FIGS. 1 and 2 is a one-push type having a shape in which a coaxial probe 52 is projected from a rotating body 51. A backing is placed on the lower side of the member to be joined such as 22, and the rotating body 51 is pressed from above to perform processing. On the other hand, there is a bobbin type friction stir welding tool 60 as shown in FIG. In the friction stir welding tool 60, a probe 62 is coaxially projected from a cylindrical rotary body 61 coupled to a drive unit of a rotary drive device, and a lower rotary body 63 is formed integrally with the probe 62. . FIG. 3 is a diagram conceptually showing the friction stir welding method of the third embodiment.

  The joined plates 21 and 22 have a portion where the abutted end surfaces are not abutted against each other and a gap 23 is generated. Also in the present embodiment, such a gap 23 is left as it is, and the belt-like plate 10 is overlaid on the joining line 20 as a filling material. The belt-like plate 10 has a plate thickness dimension larger than the maximum width of the gap 23 generated between the joined plates 21 and 22 and is made of the same material as the joined plates 21 and 22. The belt-like plate 10 is continuously arranged on the joining line 20 or is divided and arranged. However, since the belt-like plate 10 will be displaced from the joining line 20 during construction if it is just placed, the belt-like plate 10 is welded to the plates 21 and 22 to be joined in advance, or the friction stir welding using the friction stir welding tool 50 is performed. Attach multiple locations.

  After the joined plates 21 and 22 are brought into contact with each other and the belt-like plate 10 is overlaid on the joining line 20, high-speed rotation is given to the rotating body 61, the probe 62 and the lower rotating body 63 by a rotation driving unit (not shown). Is inserted so as to be pressed against the butted portions of the two butted plates 21 and 22 that have been butted. The friction stir welding tool 60 sandwiches the overlapped plates 21 and 22 and the belt-like plate 10 between the rotating body 21 and the lower rotating body 23, and relatively moves along the bonding line 20 of the bonded plates 21 and 22. Moving. As a result, the joined portion of the belt-like plate 10 and the joined plates 21 and 22 plastically fluidized is agitated and kneaded under the advance pressure of the probe 62, and plastically flows so as to wrap around the friction stir welding tool 60. It loses heat rapidly, solidifies by cooling, and is joined. At this time, even when a gap 23 is generated between the plates to be joined 21 and 22, the belt-like plate 10 as a filling material is agitated and kneaded so that the gap 23 is filled.

  Therefore, according to the friction stir welding method of the present embodiment, the friction stir welding can be performed by filling the gap 23 of the joint portion by a simple operation only by superimposing the belt-like plate 10 on the joint portions of the butted plates 21 and 22 that have been joined. It became possible to do. That is, unlike the conventional method, friction stir welding in which the gap 23 is easily filled can be performed without performing a time-consuming process of loading a filling material into a groove formed by cutting the joint. It was. And a joined part can be joined reliably and the friction stir joined body which ensured watertightness and airtightness came to be able to be provided.

Further, in the conventional method, a processing machine for forming a groove and a filling material for the joint portion is necessary, and the work for that is also necessary. However, in the friction stir welding method of the present embodiment, the belt-like plate 10 is attached. There is no need to perform special processing just by preparing it, and friction stir welding can be simplified, thus reducing processing costs.
Even when the friction stir welding tool 60 is used, the friction stir welding in which the belt-like plate 11 is superimposed on the joint portion of the extruded hollow mold members 31 and 32 of the second embodiment shown in FIG. 2 is possible. Since a backing is not required, it is effective for an extruded hollow mold member in which the top plates 35 are also abutted against each other.

  As mentioned above, although one Embodiment of the friction stir welding tool which concerns on this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.

It is the figure which showed notionally the friction stir welding method of 1st Embodiment. It is the figure which showed notionally the friction stir welding method of 2nd Embodiment. It is the figure which showed notionally the friction stir welding method of 3rd Embodiment. It is a figure which shows the outline | summary of the general friction stir welding method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Band-shaped plate 20 Joining lines 21 and 22 Plate to be joined 23 Gap 50 Friction stir welding tool 51 Rotating body 52 Probe

Claims (7)

Generated by inserting the agitation shaft of the rotated welding tool into the joint where the pair of members to be joined are abutted, and moving the welding tool relative to the member to be joined along the joining line where the joint continues. In the friction stir welding method for joining the members to be joined by stirring and kneading while softening the joint by friction heat,
A belt-like plate that is flat on the upper and lower sides of the member to be joined is overlapped along the joining line, and the stirring shaft of the rotated joining tool is inserted into the joining part and moved relatively along the joining line. A friction stir welding method comprising: stirring and kneading and joining a member to be joined and a belt-like plate at the same time by frictional heat generated in In the friction stir welding method according to claim 1,
Prior to the insertion of the welding tool, the belt-like plate overlaid on the joining line of the member to be joined is temporarily fixed in place in the longitudinal direction to the member to be joined by welding or friction stir welding. Friction stir welding method. In the friction stir welding method according to claim 1 or claim 2,
The method of friction stir welding, wherein the belt-like plate has a plate thickness that is larger than a gap of a joining line that abuts the members to be joined. In the friction stir welding method according to any one of claims 1 to 3,
The joining tool has a stirring shaft projecting from an end face of a rotating body, and presses the end face of the rotating body against the belt-like plate to perform friction stir welding. In the friction stir welding method according to any one of claims 1 to 3,
In the joining tool, a lower rotating body is integrally formed on a stirring shaft protruding from an end face of the rotating body, and a member to be joined and a belt-like plate are sandwiched between the rotating body and the lower rotating body to perform friction stir welding. A friction stir welding method characterized by the above. When a pair of members to be joined are abutted and the stirring shaft of the joining tool rotated to the joint is inserted, the joining tool moves relative to the member to be joined along a joining line where the joint is continuous, In the friction stir joined body formed by joining by softening and kneading the joint portion by the generated frictional heat,
A strip-like plate that is flat with respect to the member to be joined is overlapped along the joining line, and the stirring shaft of the joining tool rotated in that state is inserted into the joining portion and relatively moved along the joining line. A friction stir welded body characterized in that the member to be joined and the belt-like plate are simultaneously softened and stirred and kneaded by the frictional heat generated at the joint. In the friction stir bonded body according to claim 6,
The friction stir joined body, wherein the member to be joined is an extruded hollow mold material.

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