JP2006088173A - Friction stir welding method for double skin shape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction stir welding method for a double skin shape for favorably preventing the occurrence of any non-welded portion or a kissing bond on an inner surface side of a hollow part and effectively suppressing the occurrence of burrs, thereby forming a sound welded part when performing the butt-welding of the double skin shape by the friction stir welding operation. <P>SOLUTION: Hollow shapes 20a, 20b of double skin structure having face plates 22, 24 facing each other are butted to each other at end faces of the face plates 22, 24 to form butted parts 28, 30, then the friction stir welding operation is implemented so as to satisfy the predetermined conditions by using a friction stir welding tool 18 in which first and second shoulder faces 12, 14 facing each other and a probe 16 are arranged in a coaxial and integrally rotatable manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a friction stir welding method for a double skin shape material, and in particular, the friction of a double skin shape material that can advantageously prevent or suppress the occurrence of cracks by making the friction stir welding portion sound. The present invention relates to a stir welding method.

  Conventionally, a hollow shape member of a so-called double skin structure (two-sided structure), in which two face plates facing and parallel to each other are integrally connected by a plurality of ribs extending between the facing faces, It has been used for various purposes. For example, an aluminum alloy double skin profile is lightweight and has characteristics such as high rigidity and excellent smoothness by optimizing the cross-sectional shape of the profile. It is suitably used for structures, floor structures, roof structures of buildings, and the like.

  However, since such a hollow shape member is often formed by an extrusion molding method, its width dimension is limited depending on the size of the extruder, and the vehicle It has been difficult to obtain a wide profile desired in a structural body or the like by extrusion. For this reason, in general, a plurality of such hollow shapes are abutted at the end faces of the corresponding face plates, and the abutting portions are joined to form a wide joined body (panel). It is used in various applications as various structures.

  In recent years, as a kind of butt joining method for a plurality of hollow shapes, unlike arc welding (TIG, MIG, etc.), joint defects such as blow holes and solidification cracks, which are peculiar to fusion welding, are generated. Friction stir welding techniques that can be advantageously avoided have been applied in part.

  However, as shown in FIG. 1, a general friction stir welding tool (pin type tool 6) having a structure in which a pin-like hard probe 4 is provided concentrically at the tip of a rod-like tool body 2 is used. When the friction stir welding is inserted into the abutting portion of a hollow shape material such as a double skin panel while rotating at high speed, there is a risk that the joint will be bent or buckled by the pressing force of the tool. . Therefore, in order to prevent the occurrence of such buckling and the like, it was necessary to dispose a hard backing member on the back side surface of the butted portion, that is, in the hollow portion of the hollow shape member. In that case, the shape of the backing member is limited by the shape of the hollow portion, or the operation of inserting the backing member into the hollow portion or the extraction operation after joining is necessary, which makes the joining work complicated. The problem of becoming is inherent.

  In addition, when performing friction stir welding using the pin-type tool 6, a tool having a probe 4 having a length shorter by a predetermined dimension than the thickness of the face plate of the hollow shape material to be joined is generally used. Therefore, the metal cannot be sufficiently stirred in the portion where the probe 4 cannot be positioned, and for this reason, an unbonded portion or a kissing bond is formed on the back surface (inner surface of the hollow portion) side of the bonded portion. May remain, which may reduce the fatigue strength. In addition, such a bonding failure has a problem that it is difficult to detect it because it is formed inside the hollow member.

  On the other hand, Patent Documents 1 to 3 disclose a bobbin type tool (pound type tool) having a structure different from that of the pin type tool 6 described above as a friction stir welding tool. As shown in FIG. 2, the bobbin type tool includes a pair of shoulder surfaces 12 and 14 disposed so as to sandwich both surfaces of a metal plate to be joined, and the pair of shoulder surfaces 12 and 14. And a probe 16 provided coaxially therebetween. Then, such a pair of shoulder surfaces 12 and 14 are pressed from both sides so as to sandwich the metal plate, and the shoulder surfaces 12 and 14 and the probe 16 are integrally rotated at a high speed, so that , Frictional heat can be generated. For this reason, if friction stir welding is performed using such a bobbin type tool, it is possible to reliably join the surface on the hollow inner side, and thus it is extremely advantageous to cause the occurrence of poor bonding such as the above-mentioned kissing bond. Can be prevented. Further, since the pair of shoulder surfaces 12 and 14 receive (support) the mutual pressing force, an advantage that a backing member is not required can be enjoyed.

  However, when such a friction stir welding tool (bobbin type tool) 18 is used to join a hollow shape material such as a double skin panel, in addition to the joint portion on the outer surface side of the hollow portion, Also formed on the inner surface side of the hollow portion so that burrs extending in the joining direction protrude on both sides in the direction in which the joining portion extends (on the contact portion between the face plate and the shoulder surface 14 and on both sides in the joining portion forming direction), And it became clear that the problem that the sharp edge part formed by this burr | flash started as a starting point and a crack tends to arise is caused. In order to prevent the occurrence of such cracks, it is only necessary to carry out polishing or the like to remove burrs after joining. However, removing burrs formed on the inner surface side of the hollow portion is extremely difficult. It was difficult. Further, based on the occurrence of such burrs, the amount of material that is stirred and flown in the friction stir welding portion decreases, so that a defective portion of the material is generated in the direction of progress of the friction stir welding operation. The problem that appears as a joint defect is also inherent.

US Pat. No. 6,1997,745 JP 7-505090 Gazette JP 2004-42115 A

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is that when the double skin shape material is butt-joined by friction stir welding operation, on the inner surface side of the hollow portion To provide a friction stir welding method for a double skin shape material that can advantageously prevent the occurrence of unbonded portions or kissing bonds and effectively suppress the occurrence of burrs to form a sound joint portion. It is in.

  And, as a result of intensive studies to solve such problems, the present inventors have performed friction stir welding using a bobbin type tool so as to satisfy a predetermined condition, so that unjoined portions or It has been found that bonding failures such as kissing bonds can be prevented, and furthermore, the occurrence of burrs can be advantageously suppressed.

Therefore, the present invention has been completed based on such knowledge, and the gist of the present invention is that two face plates that face each other and are parallel to each other have a plurality of ribs extending between the facing faces. And by joining two hollow skins of a double skin structure that are integrally connected to each other at the end faces of the corresponding face plates to form at least one butted portion, and then friction-stir-joining the butted portion And, as a friction stir welding tool, a first shoulder surface that is rotated in contact with the surface on one side of the abutting portion, and a probe that is positioned to penetrate the abutting portion and rotated. A structure in which a second shoulder surface rotated in contact with the surface on the other side of the abutting portion is coaxially disposed is used, and the diameters of the first and second shoulder surfaces are: D When While rotating the probe together with the first and second shoulder surfaces so that the diameter d of the probe and the plate thickness Tt of the butting portion satisfy the following formula (I), A friction stir welding method for a double skin shape member characterized in that the abutting portion is friction stir welded by being moved relative to the butted portion.

  That is, according to the friction stir welding method for a double skin profile according to the present invention, a so-called bobbin having a structure capable of generating frictional heat on both surfaces of the butt portion as a friction stir welding tool. In addition to the use of a mold tool, the diameter of the first and second shoulder surfaces of the friction stir welding tool: D, the diameter of the probe that mixes and stirs the structure of the material to be joined: d, and the butt section Since the friction stir welding operation is performed so that the thickness of Tt satisfies the above formula (I), sufficient plasticization can be achieved even on the hollow portion side (inside) of the butt portion. As a result, the occurrence of unbonded parts or kissing bonds can be effectively prevented, and the metal of the stir welded part springs out from the edge of the shoulder surface of the friction stir welding tool, and burrs are generated. Occur It as also is the so that the can be very advantageously suppressed. For this reason, the occurrence of defects in the joint can be effectively suppressed or prevented, and cracks can be remarkably prevented during post-processing such as press working on the joint material. Become.

  Further, in the friction stir welding tool having the structure as described above, the butted portion is sandwiched between the first shoulder surface and the second shoulder surface, and the mutual pressing force is received on those shoulder surfaces. Therefore, there is no need for a backing member, and therefore there is no need for troublesome operations such as inserting and removing the backing member into the hollow portion, and the advantage that the work can be simplified is also enjoyed. Can be done

  Therefore, according to the present invention, for example, a target double-skin shape joined body such as a side structure or a floor structure of a vehicle or an aircraft, a roof structure of a building, etc. has a sound structure and sufficient bonding strength. It can be easily obtained.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 3 schematically shows an example of a process for obtaining a wide panel by friction stir welding of two double skin structure hollow members according to the method of the present invention. As is apparent from FIG. 3, here, each of the two double skin profiles 20a, 20b to be friction stir welded is schematically shown in cross-sectional form. The double skin members 20a and 20b have an upper surface plate 22 and a lower surface plate 24, which are opposed to each other in the vertical direction and are positioned in parallel, and have a flat plate shape. A plurality of ribs 26 (only one is shown here) extending between the opposing surfaces are integrally connected (two-sided structure).

  Examples of the material of the double skin shape members 20a and 20b include metal members such as aluminum members made of aluminum or aluminum alloys, copper members made of copper or copper alloys, magnesium members made of magnesium or magnesium alloys, and the like. The well-known material which can be friction stir welded can be mentioned. Among these, when an aluminum alloy is employed, the strength can be increased by aging treatment, Al—Cu—Mg (2000), Al—Mg—Si (6000), Al—Zn. An Mg-based (7000-based) heat-treatable Al alloy can be used particularly preferably. Further, the formation method of the double skin shape members 20a and 20b is not limited in any way, and can be formed according to various known methods. Generally, an extrusion shape material obtained by an extrusion molding operation is advantageous. Will be used.

  In the present embodiment, when the friction stir welding operation is performed on the two double skin shapes 20a and 20b, first, the two double skin shapes 20a and 20b are arranged in the width direction (in FIG. 3, The upper surface plates 22 and 22 are abutted at the end surfaces in the width direction, and the lower surface plates 24 and 24 are also abutted at the end surfaces in the width direction. Accordingly, the surfaces of the upper surface plates 22 and 22 and the lower surface plates 24 and 24 of the two double skin shape members 20a and 20b are flush with each other, and between the two double skin shape members 20a and 20b, The upper abutting portion 28 formed by abutting the upper surface plates 22 and the lower abutting portion 30 formed by abutting the lower surface plates 24 are arranged in the vertical direction that is the opposing direction of the upper and lower surface plates 22, 24. Are formed at a distance corresponding to the distance between the opposing surfaces. Further, the two double skin members 20a and 20b are abutted to each other, so that they are surrounded by the upper and lower surface plates 22 and 24 and the ribs 26 and 26, and extend in the length direction (direction perpendicular to the paper surface in FIG. 3). A hollow portion 32 is formed.

  Then, after the two double skin members 20a and 20b are fixed and restrained by a fixing jig (not shown) so that they do not move relative to each other in the vertical direction or the horizontal direction, the two double skins Either one or both of the upper butting portion 28 and the lower butting portion 30 formed between the shape members 20a and 20b are simultaneously friction stir welded. Here, the upper butting portion 28 is used. And the lower butt | matching part 30 will respectively be joined simultaneously using the predetermined friction stir welding tool 18. FIG. In the following, the joining of the upper abutting portion 28 of the upper abutting portion 28 and the lower abutting portion 30 will be described in detail, but the lower abutting portion 30 is joined similarly to the upper abutting portion 28. It should be understood that

  Here, the friction stir welding tool 18 employed in the present embodiment has two rotating members 34 and 36 as shown in FIG. Of the two rotating members 34 and 36, the first rotating member 34 has a substantially cylindrical shape as a whole, and the tip end surface thereof is a flat annular surface extending in the horizontal direction. The first shoulder surface 12 is used. The second rotating member 36 has a substantially cylindrical shape as a whole, and an outer flange portion 38 that protrudes by a predetermined dimension in the radial direction and extends continuously in the circumferential direction on the outer peripheral surface of the tip portion thereof. However, the surface of the outer flange portion 38 on the first shoulder surface 12 side is a flat surface extending in the horizontal direction and having the same outer diameter and inner diameter as the first shoulder surface 12. The second shoulder surface 14 is an annular surface.

  And the 2nd rotation member 36 has made the front end part side part including the formation part of the outer flange part 38 protrude outward from the opening part of the inner hole 40 in the cylindrical 1st rotation member 34 In the inner hole 40, the shoulder surfaces of the first and second rotating members 34 and 36 are inserted and arranged coaxially and axially (in the vertical direction) so as to be relatively movable. 12 and 14 are opposed to each other at a predetermined distance in the vertical direction and are positioned in parallel. Further, the tip portion excluding the outer flange portion 38 of the second rotating member 36 that is protruded outward from the tip portion of the first rotating member 34 by a predetermined length, that is, the first and second shoulders. A portion between the surfaces 12 and 14 is a probe 16. The first and second shoulder surfaces 12 and 14 and the probe 16 are formed of a material harder than the material of the double skin shape members 20a and 20b to be joined. Therefore, they are rotated at a high speed. Thus, even if it is brought into contact with the double skin members 20a and 20b, it is a non-consumable member that hardly wears.

  Although not shown in the figure, here, the first and second rotating members 34 and 36 are connected to separate motors or the like synchronized with each other at their respective base portions, and are integrally rotated. To get. Further, the base side portions of the respective rotary members 34 and 36 are respectively connected to separate hydraulic cylinders that are protruded / retracted by a known hydraulic mechanism, and the protrusions / retracts of the respective hydraulic cylinders are performed. As a result, the hydraulic cylinders are stopped at a predetermined operating position, so that the rotating members 34 and 36 stop the relative movement in the vertical direction at an arbitrary moving position. It is supposed to be. In other words, the outer flange portion 38 of the second rotating member 36 can move toward and away from the first rotating member 34 in a state where the outer flange portion 38 can rotate integrally with the first rotating member 34. The distance between them can be arbitrarily adjusted.

  Thus, the shoulder surface 12 of the first rotating member 34, the shoulder surface 14 of the second rotating member 36, and the probe 16 can be integrally rotated, and the length of the probe 16 (first and second). The distance between the shoulder surfaces 12 and 14 is arbitrarily adjusted to maintain a desired length.

  Thus, using the friction stir welding tool 18 having the above-described structure, the operation of friction stir welding the upper butt portion 28 formed between the two double skin shape members 20a and 20b is performed according to the present invention, for example, as follows. In this way, it will be implemented.

  That is, first, the second rotating member 36 of the friction stir welding tool 18 is moved up and down (relatively moved) in the vertical direction with respect to the first rotating member 34, and the shoulder of the first rotating member 34 is moved. The distance between the surface 12 and the shoulder surface 14 of the second rotating member 36, that is, the length of the probe 16 is the same as the plate thickness Tt of the upper abutting portion 28 (upper surface plate 22). The second rotating member 36 is made immovable (fixing the distance between the shoulder surfaces 12, 14).

  Next, the first and second rotating members 34 and 36 are integrally rotated, and thereafter or before that, the probe 16 composed of the lower end portion of the second rotating member 36 is placed on the upper abutting portion 28. On the other hand, it is positioned so as to penetrate through, but this is performed, for example, by one of the following two arrangement methods (1) or (2).

  That is, in the arrangement method (1), the side surface of the probe 16 is brought into contact with the end surface of the upper butting portion 28 on the joining start side under the state where the first and second rotating members 34 and 36 are integrally rotated. The probe 16 is pressed and pressed along the upper abutting portion 28 toward the joining end side. As a result, the probes 16 are respectively inserted into the joining start side end portions of the upper abutting portion 28 and are positioned so as to penetrate through the upper abutting portion 28.

  When the arrangement method (2) is performed, first, as shown in FIG. 4, the probe 16 can be inserted in advance into the corresponding portion at the end of the upper butt portion 28 on the joining start side. The hole 42 is drilled so as to penetrate in the vertical direction. As shown by a two-dot chain line in FIG. 4, when the upper surface plate 22 of the two double skin shape members 20a, 20b is canceled, the insertion hole 42 formed in the upper butt portion 28 is removed. These are formed as semicircular cutouts on the widthwise ends of the upper surface plates 22.

  Then, once each of the insertion holes 50 is formed, the butted state of the two double skin shape members 20a and 20b is once canceled (a state indicated by a two-dot chain line in FIG. 4). Then, after the probe 16 of the friction stir welding tool 18 is positioned between the end faces of the upper surface plate 22 in a state where the integral rotation of the first and second rotating members 34 and 36 is stopped, Again, the two double skin profiles 20a, 20b are butted together. As a result, the probe 16 is inserted into the insertion hole 42 provided in the upper abutting portion 28, so that the probe 16 is positioned in the upper abutting portion 28 so as to pass through them. I'm damned. In this case, for example, the first and second rotating members 34 and 36 are integrally rotated after the re-matching operation of the two double skin shapes 20a and 20b.

  Therefore, in the state where the probe 16 is positioned so as to penetrate the upper abutting portion 28 by any one of the arrangement methods (1) and (2) as described above, or by another method other than these, As the first and second rotating member jigs 34 and 36 are integrally rotated, the shoulder surface 12 of the first rotating member 34 and the shoulder surface 14 of the second member 36 are integrally rotated while being rotated together. The outer surface 44 and the inner surface 46 of the butt 28 are brought into contact with each other.

  As a result, frictional heat is generated at the contact surface between the butting portion 28 and the probe 16 and the shoulder surfaces 12 and 14, and the periphery thereof is plasticized. The tissues of the end portions of the face plates 20a and 20b come in and mix with each other.

From such a state, the friction stir welding tool 18 is relatively moved integrally with the upper abutting portion 28 along the upper abutting portion 28 (in the direction of arrow A in FIG. 4). Although the portion 28 is friction stir welded, in the present invention, the friction stir welding is advanced so as to satisfy the following formula (I).

  In the above formula (I), D indicates the diameter of each of the first and second shoulder surfaces 12 and 14 of the friction stir welding tool 18, d indicates the diameter of the probe 16, and , Tt indicate the plate thickness of the upper butt portion 28 (upper surface plate 22) which is a bonded portion.

  Here, the inequality on the left side in the above formula (I) is an expression representing the relationship between the plate thickness of the butting portion and the radius (d / 2) of the probe 16. In the present invention, the plate thickness is the probe 16. Must be equal to or greater than the radius of. This is because when the plate thickness is smaller than the radius of the probe 16, that is, when the diameter of the probe 16 is too large with respect to the plate thickness of the upper butt portion 28, which is the bonded portion, This is because there arises a problem that it cannot be formed. More specifically, at the time of friction stir welding, when the friction stir welding tool 18 is moved relatively along the abutting portion 28, if the probe 16 is too thick relative to the plate thickness, plasticization is caused by frictional heat. The metal of the upper butt portion 28 thus made does not sufficiently wrap around the rear side in the traveling direction of the probe 16, and the metal does not spread so as to fill the hole formed by the penetration of the probe 16, and a healthy joint portion is formed. You won't get it.

On the other hand, the inequality on the right side in the above formula (I) is an expression derived from the following formula (II), and the left side of the formula (II) represents the area (S ₁ ) of the cross section of the probe 16 including the axis. On the other hand, the right side of the formula (II) is an area (S _{2) obtained} by combining the areas of the first shoulder surface 12 and the second shoulder surface 14 brought into contact with the outer surface 44 and the inner surface 46 of the butt 28, respectively. ).

That is, in the present embodiment, the cross-sectional area (S ₁ ) of the probe 16 is equal to or smaller than the total area (S ₂ ) of the first and second shoulder surfaces 12 and 14. It is necessary to perform friction stir welding. In this way, when the upper abutting portion 28 is friction stir welded, the metal of the stir joint pushed out by the penetration of the probe 16 to the outer surface 44 side or the inner surface 46 side is the first and second of the friction stir welding tool 18. Projecting from the shoulder surfaces 12 and 14 and springing out from the respective edges of the shoulder surfaces 12 and 14 is extremely effectively prevented and is sufficiently suppressed within the surfaces, resulting in cracks. As a result, the generation of burrs that can cause the occurrence of this is effectively suppressed or prevented.

The diameter D of the shoulder surface is not particularly limited as long as it satisfies the formula (I) as described above, but as shown in FIG. A width smaller than L of the flat portion in the direction orthogonal to the joining direction of the inner surface 46 of the hollow portion in contact is adopted. Further, although there is no limitation on the relationship between the diameter of the shoulder surface: D and the diameter of the probe: d and the relationship between the diameter of the shoulder surface: D and the plate thickness: Tt, it is not limited at all. In order to realize the parts more advantageously, it is desirable to satisfy the following formula (III) or the following (IV), respectively.
1.5d ≦ D ≦ 4d (III)
1.2 Tt ≦ D ≦ 16 Tt (IV)

  Further, in the present embodiment, the shoulder surface 12 of the first rotating member 34 and the shoulder surface 14 of the second rotating member 36 are respectively applied to the outer surface 44 and the inner surface 46 of the upper butt 28 in a rotating state. Since the contact is made, the entire upper butt 28 is sufficiently plasticized by the frictional heat generated between the contact surfaces, and the entire upper butt 28 (from the outer surface 44 side to the inner surface 46). Metal) is effectively agitated. For this reason, not only the outer surface 44 side but also the inner surface 46 side of the joint portion is sufficiently joined, and a healthy joint portion with no joint failure such as an unjoined portion or a kissing bond is advantageously formed. Become.

  In addition, in the present embodiment, the two double-skin shape members 20a and 20b are abutted against each other from the place where the mutual pressing force is received between the pair of shoulder surfaces 12 and 14. Depending on the shape of the hollow portion 32, there is no need for any work such as preparing a backing jig or inserting the backing jig into the hollow portion 32, and simplifying the joining work, It can be advantageously achieved.

  Moreover, in the present embodiment, since the friction stir welding operation of the lower butt portion 30 of the lower surface plate 24 is also performed simultaneously with the friction stir welding operation of the upper butt portion 28 of the upper surface plate 22, It is possible to advantageously shorten the working time of the joining work of the two double skin members 20a and 20b, and the occurrence of the bending of the face plates 22 and 24 of the double skin members 20a and 20b after joining is effective. It can be avoided, and it can be advantageously avoided that the finally obtained joined body is distorted. If the two butted portions 28 and 30 are sequentially friction stir welded, the previously formed joined portion slightly contracts, the face plate warps, and it becomes difficult to join the butted portion to be performed next. When the upper butt portion 28 and the lower butt portion 30 are joined simultaneously and in parallel, a wide panel having a double skin structure with a small balance of shrinkage can be obtained.

  Therefore, according to the present embodiment, it is possible to stably obtain a wide panel having a target double skin structure with a bonding portion having sound and sufficient bonding strength without bonding defects such as burrs and kissing bonds. Is possible. Such a joined product is advantageously used as a side structure or floor structure of a vehicle, an aircraft, or the like, or a roof structure of a building, especially as a bridge slab such as a road bridge or a footbridge.

  The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.

  For example, in the above embodiment, as the double skin profile, the upper and lower plates 22 and 24 to be abutted have a constant thickness in the width direction and the length direction. If it is too thin compared to the thickness, the portion of the free end forming the butt portion is designed to be thick so as to satisfy the formula (I) as described above, that is, the thickness of the upper and lower surface plates in the width direction. Of course, it is possible to change. In the above example, the ribs 26 are formed perpendicular to the upper and lower surface plates 22 and 24. However, the ribs 26 may be formed in a shape inclined at a predetermined angle. It can be adopted.

  Furthermore, in the said embodiment, although the 1st and 2nd shoulder surfaces 12 and 14 were all flat surfaces, the concave shape curved toward the center may be sufficient, and a conventionally well-known shape is used. Can be employed as appropriate.

  In addition, although not listed one by one, the present invention can be implemented in a mode with various changes, modifications, improvements, and the like based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the invention.

  Hereinafter, representative examples of the present invention will be shown and the present invention will be clarified more specifically. However, the present invention is not limited by the description of such examples. It goes without saying.

  First, as a double skin shape material to be joined, it is made of an aluminum alloy (6N01-T5), and the thickness, overall height, width and length of the upper and lower surface plates are respectively shown in Table 1 below. Two each were prepared. Further, two friction stir welding tools made of steel having a structure as shown in FIG. 3 were prepared as friction stir welding apparatuses. The diameters of the first and second shoulder surfaces and the probe diameter are shown in Table 1 below.

  Then, the prepared two double skin sections are butted in the width direction, and corresponding upper butting sections and lower butting sections are formed in the facing direction of the two face plates of each extruded section, respectively. Two double skin profiles were restrained and fixed.

  On the other hand, the second rotating member of each friction stir welding tool is moved relative to the first rotating member so that the distance between the first and second shoulder surfaces is the same as the thickness of the face plate. Adjusted. Then, while rotating each friction stir welding tool at a rotational speed of 1000 rpm, the side surfaces of each probe are pressed against the end surfaces on the joining start side of the upper and lower abutting portions, respectively, and each probe is moved to the upper and lower abutting portions. Entered each. At this time, the first shoulder surface of each friction stir welding tool was in contact with the outer surface of the butting portion, and the second shoulder surface was in contact with the back surface (hollow portion inner surface) of the butting portion.

  Thereafter, the first and second rotating members of each friction stir welding tool are horizontally aligned along the abutting portion and in parallel with the two friction stir welding tools under the conditions of rotational speed: 1000 rpm and welding speed: 500 mm / min. The upper and lower butt portions were simultaneously friction stir welded to obtain the desired wide panel.

  And when the obtained wide panel was cut | disconnected in the direction orthogonal to a joining direction and the cross section of the junction part was observed visually, about Example 1, no defect was recognized. In Comparative Example 1, the plate thickness was smaller than the radius of the probe, the face plate was torn at the abutting part, and in Comparative Example 2, a burr was formed and a tunnel-like hole was formed in the center of the stirring part. .

  Furthermore, as a result of conducting a tensile test and a static four-point bending test of a wide panel by a known method, in Example 1, the fracture occurred at the face plate portion away from the joint, whereas Comparative Example 1 and Comparative Example In Example 2, fracture occurred at the joint and the strength was inferior to that of Example 1.

  As is clear from the above results, if friction stir welding is performed in accordance with the present invention so as to satisfy a predetermined condition, the occurrence of unbonded portions or kissing bonds on the inner surface of the hollow portion side is advantageously prevented. In addition, the generation of burrs can be advantageously suppressed, so that a bonded product with high bonding strength can be manufactured.

It is a schematic explanatory drawing which shows the conventional friction stir welding tool. It is a schematic explanatory drawing which shows one specific example of the friction stir welding tool which has a structure according to this invention. FIG. 3 is an explanatory cross-sectional view showing an example of a process when two double skin shaped members are friction stir welded using the friction stir welding tool shown in FIG. 2. It is explanatory drawing which shows another example of a process at the time of friction stir welding of two double skin shape members according to this invention.

Explanation of symbols

12 First shoulder surface 14 Second shoulder surface 16 Probe 18 Friction stir welding tool 20a, 20b Double skin profile 22 Upper surface plate 24 Lower surface plate 26 Rib 28 Upper butt portion 30 Lower butt portion 32 Hollow portion 34 First Rotating member 36 Second rotating member 38 Outer flange portion 40 Inner hole 42 Insertion hole 44 Outer surface 46 Inner surface

Claims (1)

Two face plates that are parallel to each other and are connected to each other by a plurality of ribs extending between the opposing faces are connected to each other by connecting two end faces of the corresponding face plates. In which at least one butt portion is formed, and then the butt portion is friction stir welded,
As a friction stir welding tool, a first shoulder surface that is rotated in contact with the surface on one side of the abutting portion, a probe that is positioned so as to penetrate the abutting portion and rotated, and a A structure in which a second shoulder surface rotated in contact with the surface on the other side is coaxially disposed is used, and the diameters of the first and second shoulder surfaces: D and the probe The butt portion is rotated while the probe is driven to rotate together with the first and second shoulder surfaces so that the diameter d of the butt and the plate thickness Tt of the butt portion satisfy the following formula (I): A friction stir welding method for a double skin shape material, characterized in that the abutting portion is friction stir welded by being moved relative to the surface.

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