DE102008019062B4 - A seam-sealed article, a method of manufacturing an article, and a friction stir tool and a friction stir device - Google Patents

Abstract

An article (19) of at least one fiber reinforced material having a welded seam (18), wherein a fiber (4) is disposed in the seam (18), characterized in that the fiber (4) extends over almost the entire length of the seam and in the seam has a helical shape.

Description

The invention relates to an article with a welded seam, a method for producing an article, in particular with a friction stir process, as well as a friction stir tool and a device for friction stir.

Aerospace, railway and automotive applications require complex and large parts, traditionally made of several interconnected components. Joining fiber reinforced composite parts, such as by welding techniques, poses new challenges because the parts are made of at least two different materials, the matrix material and fibers embedded therein.

Fiber reinforced composites such as fiber reinforced plastics and fiber reinforced metals and alloys have higher strength than the matrix material alone and lower weight than conventional metallic structures. As a result, they are increasingly used in aerospace, railway and automotive engineering.

The DE 199 55 737 A1 describes a method and apparatus for joining two adjacent workpieces by the method of friction stir welding. Other devices and methods for friction stir welding are in US Pat. No. 6,543,671 B2 or EP 1 872 893 A1 described.

The WO 2003/092 986 A1 describes a method of increasing the strength of particle-reinforced polymer vibration weld joints.

The US 3 900 360 A describes a structure for joining incompatible articles.

The JP 63-053 013 A describes a method for electrical heating and bonding.

The JP 2001-310 539 A describes a nylon fabric with a weld, wherein in the vicinity of the weld or around the weld in addition, a stitched seam is provided. The object of the invention is therefore to provide a method for producing an article which is suitable for reliably joining fiber-reinforced materials together, as well as to provide an article of at least two interconnected fiber-reinforced materials. It is another object of the invention to provide a tool and a device with which this method can be performed.

The object is achieved by the subject matter of independent claims 1, 5, 11, 24, 27 and 29. Further advantageous developments emerge from the respective dependent claims.

According to the invention, an article of at least one fiber-reinforced material with a welded seam is provided, wherein at least one fiber is arranged in the seam.

When welding fiber reinforced materials by conventional methods, only the matrix material is welded and melted. The fibers remain firm and unmelted. This leads to a seam, which consists only of the weld metal. The seam thus has no reinforcing fibers and consequently less strength than the body of the joined parts. Thus, under mechanical stress of the article, cracks in the seam may form or spread which may result in breakage of the seam and breakage of the article. This is avoided with the article according to the invention, since the seam has at least one fiber which reinforces the seam itself.

According to the invention, the fiber extends almost over the entire length of the seam. This has the advantage that the seam is homogeneously reinforced by the fiber, so that the reliability of the connection is increased.

Furthermore, the fiber has a helical or spiral shape, in particular a helical shape. This shape has the advantage that the width and the length of the seam are reinforced by the fiber. The pitch and diameter of the helix (i.e., the helix) may be approximately the same over the entire length, or may vary.

In one embodiment, multiple fibers are disposed in the seam. These fibers may be entangled or juxtaposed. The proportion of fibers in this way in the seam can be increased in order to further increase the strength of the seam. It is advantageous if the strength of the seam approximately corresponds to the strength of the non-welded parts, so that the strength of the object is spatially equal.

The fibers introduced into the seam may be continuous fibers, but also short or long fibers.

The article of any of these embodiments may be a component of an aircraft or a motor vehicle. In particular, in aircraft and motor vehicles can crack due to continuous load of the components caused. Of course, this is to be avoided for safety reasons.

The invention also provides a friction stir method which can be used to manufacture the article of any one of the preceding embodiments.

Friction stir processing and friction stir welding (FSW) are known to contact and hold two workpieces to be welded together. In the connecting region of the workpieces, a welding pin or a pin-shaped projection of a corresponding tool is inserted under rotary motion until a shoulder arranged above the welding pin on the tool rests on the surface of the workpieces. In this case, frictional heat is generated by the relative movement between the tool and workpieces, so that adjacent material regions assume a plasticized state in the connection region. The tool, while the rotating welding pin is in contact with the connecting portion, is advanced along the joining line of the workpieces so that the material around the welding pin is plasticized and then consolidated. Before the material hardens completely, the welding pin is removed from the connection area or the workpieces.

Parts made from fiber-reinforced materials, such as metal composite materials (so-called MCCs) or suitable plastic materials can be welded together in this way as a butt joint, lap joint or T-joint connection. The technique of friction friction is also used in the repair, processing and finishing of workpieces. Point connections can also be generated, whereby forward movement of the welding pin rotatingly in contact with the connection area or a translatory relative movement between the rotating welding pin and workpieces does not take place.

According to the invention, the method comprises the following steps. A rotationally driven pin-shaped projection is inserted into a workpiece area or into a connecting area of at least two adjoining workpieces with rotating movement. The workpiece area or joint area is plasticized in at least one contact area between the rotating projection and the workpiece area or bonding area, and a fiber is introduced into the plasticized area.

The introduced fiber may be an endless fiber which is preferably fed continuously. But it can also be introduced short or long fibers. In order to simplify the feeding of short fibers or long fibers, they may be embedded in a filler material (fiber-reinforced filler material) which is introduced into the plasticized region.

The plasticized area is liquid so that a fiber can be introduced into this liquid area. This plasticized area has circulating currents caused by the rotation of the protrusion. An endless, solid fiber is captured by this circulating weld metal and positioned in the weld metal due to flow or flow. Consequently, after re-solidification of the plasticized area, the endless fiber having a flow-related shape is frozen in the seam between the workpieces.

Due to these circulating currents, the endless fiber becomes helical, i. H. spiral or helical, arranged in the seam, wherein the projection along the connecting line is guided linearly. By combining the linear motion and the circulating currents in the weld metal, the pitch of the helix can be adjusted.

The rotatably driven pin-shaped projection is typically part of a friction stir tool that includes a rotationally drivable tool body. At the end of the tool body facing away from the drive, a shoulder is provided, from which the rotatable, pin-shaped projection, which has a smaller diameter than the shoulder, extends in the direction of the drive end of the tool body. The shoulder and the pin-shaped projection are independently driven in rotation.

The shoulder may have at least one passage opening which extends in the direction away from the drive end of the tool body. A fiber may be disposed in the through hole and supplied to the plasticized portion of the workpiece or the bonding portion during the friction stir process.

According to one embodiment of the method according to the invention, the shoulder is applied to the workpiece region or connecting region under at least temporary pressurization, wherein, while the projection is in contact with the workpiece region or connecting region, the rotational speed of the shoulder has n = 0.

This method is advantageous when welding thick workpieces, in particular plates with a thickness greater than 6 mm. It is important in turn that during the rotationally driven pin-shaped projection in contact with the Material or connection area is, the shoulder does not rotate, so that no additional heat of friction generated on the workpiece surface through the shoulder. Thus, the heat input is significantly reduced by Reibwärmegenerierung on the surface of the workpieces, creating a so-called low-heat joining is possible. The additional heating on the workpiece surface is eliminated, so that here the heat load is low and at the same time a homogeneous heat load over the entire penetration depth of the welding pin is ensured. At the same time, the workpiece alloys soften less because the heat affected zone is less pronounced. Another positive effect is that residual stresses are reduced, so that the risk of delay is lower and an occurring delay is easier to handle.

The pointing in the direction of the pin-shaped projection surface of the workpieces is applied at a given time by the action of the shoulder with the required pressure, which is advantageously reduced compared to conventional friction stir by a factor of 2 to 3 and is typically between 1 and 200 kN. Thus, you can work with reduced process force, which in turn has a simplified system technology result. In addition, the process-related change in the residual stress states of the welded, repaired, machined or converted workpieces is reduced.

The fact that no additional friction is caused by the non-rotating shoulder, also causes the process with a higher speed or rotational speed of the welding pin can be performed. The speed can be increased by a factor of 3 to 4 compared to conventional friction stir process and is typically between 200 and 5000 revolutions per minute.

In another embodiment, the shoulder is applied to the workpiece area or joint area under at least temporary pressurization, wherein while the projection is in contact with the workpiece area or joint area, the rotational speed of the shoulder is less than the rotational speed of the projection. This embodiment makes it possible to set the shape of an endless fiber in the seam, since the shape is determined not only by the flow of the plasticized portion but also by the speed of rotation of the shoulder.

According to a further embodiment, the projection in the workpiece region or connecting region is moved linearly, wherein the fiber is continuously introduced into the plasticized region. This embodiment is used to introduce a long or continuous fiber into a long seam.

For joining two abutting workpieces, the projection can be moved relative to the abutting workpieces along the line connecting the abutting workpieces. Alternatively, the abutting workpieces are moved relative to the projection along the joining line of the abutting workpieces.

The invention also provides a friction stir tool which comprises a rotationally drivable tool body, at the end remote from the drive, a shoulder is provided, from which extends in the direction of the drive end facing away from the tool body, a rotatable, pin-shaped projection having a smaller diameter than the shoulder, wherein the shoulder and the pin-shaped projection are independently driven to rotate. According to the invention, the shoulder has at least one passage opening which extends in the direction away from the drive end of the tool body.

A fiber may be disposed in the through hole and inserted into the plasticized region of the workpiece or the bonding region during the friction stir process. This arrangement has the advantage that the through-hole and the position of insertion of the fiber are as close as possible to the plasticized region. This allows for reliable insertion of the fiber into the seam.

In a further exemplary embodiment, the passage opening widens in the direction of the drive-away surface of the shoulder. The fiber can be introduced through this passage opening directly above the workpiece in the plasticized area.

The passage opening may extend substantially perpendicular to a surface of the shoulder facing away from the drive. This has the advantage that the guide length of the fiber arranged in the shoulder is small.

In a further embodiment, the passage opening extends from a surface facing away in the direction of the shoulder to a surface facing away from the projection in the direction of the shoulder. This arrangement has the advantage that the fiber source is arranged next to the tool body. This can simplify the structure of the arrangement.

In a further embodiment, the shoulder is designed such that upon rotation the pin-shaped projection has a speed n = 0. The central idea here is to design a friction stir tool in such a way that the welding pin and shoulder are decoupled from each other, so that upon rotation of the welding pin the shoulder just does not perform any rotational movement, but with respect to the workpieces to be joined or machined in the sense of rotation or is fixed. However, this does not exclude a displacement of the shoulder in the axial direction of the tool. In this case, the shoulder defines a region of the friction stir tool having a larger diameter than the welding pin and ensures that, starting from a certain penetration depth of the welding pin, the shoulder rests positively and positively on the workpiece surface in order to apply the required pressure force to the workpiece surface and to prevent the escape of plasticized material ,

According to a preferred embodiment, the shoulder is freed by means of a suitable bearing of the tool body or of the pin-shaped projection driving spindle rotation and thus contributes deliberately no additional frictional heat to the welding process, but is able to provide the necessary vertical force on the workpieces to be joined transfer. The shoulder is preferably mounted on the tool body by means of rolling bearings. Such bearings are for example ball, barrel, needle roller bearings or the like. Alternatively, hydrostatic or hydrodynamic plain bearings can be used to support the shoulder, to name but a few more examples.

Advantageously, the shoulder is formed as a molded part, which is arranged on the side facing towards the pin-shaped projection side of the bearing. The molded part, which is for example a sheet-like element (eg a steel sheet with a thickness of typically 2 to 5 mm) or a cast component, may for this purpose be provided with a bore for passing the pin-shaped projection, and from below (ie Direction of the pin-shaped projection) are pushed onto the bearing. It is important to ensure that the area between the molding and pin-shaped projection is formed as tight as possible in order to prevent escape of plasticized material in the axial direction of the friction stir tool.

Alternatively, an arrangement with a molded part without storage can be used.

Furthermore, it is advantageous that the edge region of the molded part is angled in such a way that it at least partially surrounds the bearing. It is particularly advantageous if the molded part at least partially surrounds both the side regions of the bearing and the surface of the bearing pointing in the direction of the tool drive. In this way, it is ensured that when removing the tool or the pin-shaped projection from the workpiece or connecting region, the shoulder does not slip or move in the axial direction of the tool. At the same time it is counteracted by adhesion of the shoulder to the surface of the welded or machined workpieces.

Conveniently, the molded part is provided with a friction-reducing material at least on its side facing the projection. For this purpose, for example, the material "CC Aluspeed <(RTM)>" from Cemecon can be applied as a coating. As a result, the friction between the molded part and the workpiece surface is additionally reduced, which corresponds to the function of a sliding shoe.

According to an alternative embodiment, the shoulder is formed by the side facing in the direction of a corresponding bearing arranged on the tool body (for example plain or roller bearings). This represents a particularly simple embodiment since an additional element (for example, the molded part) can be dispensed with.

In this alternative embodiment, too, it is expedient to coat the side of the bearing pointing in the direction of the projection with a friction-reducing material of the aforementioned type, in order in turn to reduce the friction between shoulder and workpiece surface.

Conveniently, the pin-shaped projection is formed integrally with the tool body, resulting in a very simple structure and the system technology for driving the tool or the pin-shaped projection is extremely simple, since essentially only one spindle to be driven is required. In this case, the friction stir tool is usually rotationally symmetrical.

The friction stir tool according to the invention ensures that the work piece material close to the shoulder is not overheated. Thus, when welding workpieces, it is ensured that the root area of the welded joint, which otherwise tends to become cold-weldable, is welded securely and with high quality thanks to the higher selectable welding pin rotational speed in comparison with known friction stir welding tools. A uniform temperature distribution over the entire cross-section of the workpieces is achieved, which is a prerequisite for a high-quality welded joint.

In addition, the tool according to the invention can be used in an analogous manner for the repair, processing and finishing of workpieces.

The invention also provides a device for friction stir, comprising a friction stir according to one of the preceding embodiments. The protrusion is insertable into a workpiece area or a connecting area of at least two workpieces to be connected with rotating movement, so that when it is rotated in contact with the workpiece area or connecting area, the protrusion plastifies this plasticized material at least in the contact area. The apparatus further comprises a fiber source, wherein fibers may be introduced into the plasticized material via the passage opening. The fibers can be supplied for example in the form of continuous, short or long fibers.

The device may further comprise drive means with which the device can be guided linearly while the drive of the projection is rotating. Alternatively, the workpieces are moved linearly relative to the device, in particular the projection.

In one embodiment, the shoulder may be applied to the workpieces outside the contact area between the protrusion and the workpiece area or joint area. The shoulder can thus be driven perpendicular to the workpieces, thus causing a pressurization of the workpiece.

The friction stir tool and the device according to one of the preceding embodiments can be used for welding fiber-reinforced plastics, fiber-reinforced metals or fiber-reinforced alloys, or for welding two adjoining workpieces made of fiber-reinforced plastic, fiber-reinforced metal or a fiber-reinforced alloy.

The invention will now be explained in more detail with reference to the drawings.

1 shows a cross section of an apparatus for friction stir of a fiber reinforced material with a friction stir tool and a fiber source,

2 a plan view of the device according to 1 , and

3 shows a perspective view of a component of two workpieces, with the device according to 1 be welded together.

1 shows a cross section of a device 1 for friction stir. The device 1 has a friction stir tool 2 , a fiber source 3 For example, a coil with an endless fiber 4 , And a drive, not shown. 1 also shows the use of the device 1 for joining workpieces, in this embodiment, two fiber-reinforced joining parts 5 . 6 are.

The fiber-reinforced joining parts 5 . 6 have a matrix material made of thermoplastic, for example polypropylene, in which endless fibers, such as carbon fibers, are arranged. The parts to be joined 5 . 6 are in 1 arranged in butt joint connection adjacent to each other. Of course, the joining parts 5 . 6 also be welded overlapping or T-joint connection with each other, which will not be described in detail below, but mutatis mutandis from the following description, so that the invention is not limited to the embodiments described below.

The friction stir tool 2 is rotationally symmetrical and includes a tool body 7 , which is formed at the top, ie at the drive end, typically in the form of a bearing shaft to a tool holder in a 1 not shown drive device (eg., Rotary motor) to be recorded. At the drive end facing away from the tool body 7 is a shoulder 8th provided, from the direction in the direction away from the drive end of the tool body 7 a rotatable, pin-shaped projection 9 or welding pin 9 extends. The pin-shaped projection 9 has a smaller diameter than the shoulder 8th on.

At the in 1 illustrated embodiment, the pin-shaped projection 9 integral with the tool body 7 formed, which is a particularly simple arrangement, since only a drive mechanism for rotating the tool body 7 and thus the pin-shaped projection 9 is required. The axis of rotation of the friction stir welding tool 1 is in 1 represented by the dashed line.

Alternatively, the tool body 7 a mechanism (not shown) for receiving the welding pin 9 have, so that a replacement or displacement of the welding pin 9 along the axis of rotation (ie in the axial direction) is easily possible.

Regardless of whether the pin-shaped projection 9 integral with the tool body 7 or is designed interchangeable, is the shoulder 8th preferably by means of roller bearings 10 on the tool body 7 arranged. Such bearings 10 can be, for example, ball, barrel or needle roller bearings. By the storage of the shoulder 8th with the rolling bearings ensures that the shoulder 8th and the welding pin 9 or the tool body 7 are independently drivable. In a preferred embodiment, upon rotation of the welding pin 9 or the tool body 7 the shoulder 8th no rotational movement and thus has a speed n = 0. That way, the shoulder becomes 8th from the welding pin 9 driving rotation freed or decoupled.

Instead of storage by means of roller bearings and hydrostatic or hydrodynamic bearings can be used. However, the function of storage is the same. Alternative can be dispensed with a storage.

In 1 is the shoulder 8th designed as a molded part. Such moldings may be sheet-like elements (eg steel sheets), castings or the like, advantageously on their in the direction of welding pin 9 facing side are provided with a friction-reducing coating to reduce the friction between the shoulder 8th and the surface of the workpieces 5 . 6 in addition to diminish. For this purpose, for example, the material CC Aluspeed <(RTM)> Cemecon can be used. The edge region of the molded part can be in the axial direction of the friction stir tool 2 pointing angled and rest against the sides of the lower bearing shell. To cling to the shoulder 8th on the welded fiber-reinforced parts 5 . 6 or a shift of the shoulder 8th to avoid in the axial direction, the molded part, the rolling bearing 10 Also surrounded up to its direction towards the drive end facing side.

In the design of the molding is to ensure that a good seal between the shoulder 8th and welding pin 9 is ensured, so that plasticized material not in the axial direction, ie in the direction of the drive-facing end of the tool body 7 , can escape. This can be achieved, for example, by a hole arranged in the molding, which corresponds to the diameter of the welding pin 9 is adjusted. The molding can, for example, from below via the welding pin 9 on the camp 10 be deferred.

The shoulder 8th also has a passage opening 11 on, extending in the direction of the drive end facing away from the tool body 7 extends, and in this embodiment approximately perpendicular to the drive-facing surface of the shoulder 8th is arranged. The passage opening 11 is in the shoulder 8th next to the welding pin 9 arranged (see also 2 ). The endless fiber 4 is from the fiber source 3 through the passage opening 11 fed, leaving the end of the fiber 4 below the drive end remote from the tool body 7 is arranged.

For welding the adjoining fiber-reinforced joining parts 5 . 6 becomes the pin-shaped projection 9 as you know, under rotating motion in the connection area 12 the parts to be joined 5 . 6 introduced and along the connecting line 13 the parts to be joined 5 . 6 moved forward. This forward movement is with the arrow 14 in the 2 shown. The rotation of the projection 9 is with the arrow 15 in the 1 and 2 shown.

The rotating movement of the welding pin 9 on the surface of the fiber-reinforced parts 5 . 6 generates frictional heat due to the relative movement between tool and workpieces. This frictional heat leads to plasticization of the adjacent plates in the contact area, so that the rotating welding pin 9 can be introduced into the connection area. The plasticized substance 17 arises at the connecting line and flows circulating around the welding pin 9 around. This is with the arrows 16 in the 1 shown. The currents flow in horizontal circles as well as in vertical circles. The fiber 4 is in this plasticized substance 17 introduced, with the fiber 4 by means of the welding pin 9 excited material flow of the matrix material of the parts to be joined 5 . 6 is detected by the circulating weld metal and is positioned flow-dependent or flow-dependent in the weld metal.

The welding pin 9 is while the rotating welding pin 9 in contact with the connection area 12 stands, linear along the connecting line 13 between the two plates 5 . 6 emotional. The connection area 12 is plasticized in the forward direction and the endless fiber 4 continuously to the plasticized area 17 fed. In the reverse direction, the connection area solidifies 12 again, so the fiber 4 in the welded seam 18 is frozen. Consequently, a fiber reinforced material component is provided in which the seam 18 as well as the workpieces 5 . 6 fiber reinforced. Due to the flow-dependent or flow-dependent positioning of the fiber 4 in the weld metal can be a seam 18 be provided, in which the fiber 4 in the seam 18 has a helix shape. This is in the 3 shown.

The object 19 thus has two fiber-reinforced joining parts 5 . 6 on, over a welded seam 18 connected to each other. An endless fiber 4 with a helix shape is in the seam 18 arranged and extends along the longitudinal direction of the seam 18 , The object 19 has a fiber reinforced seam 18 as well as fiber-reinforced joining parts 5 . 6 and can be used as a component for an aircraft or a motor vehicle.

The inventive method provides a solid state welding of continuous fiber reinforced metals and plastics, in which at the same time a targeted fiber positioning is achieved in the weld metal. This has the advantage that not only the matrix materials are welded together. In conventional friction stir welding continuous fiber reinforced materials, the fibers in the contact area between the welding pin 9 and the parts to be joined 5 . 6 be severed so that the strength of the compound comes only from the organic or metallic matrix material. This strength is significantly lower than that of the fiber-reinforced material. This is avoided by the inventive targeted positioning of an additional fiber in the welded seam, so that the strength of the seam is increased and the welded component is more reliable and resilient.

Preferably, the shoulder rotates 8th not while the welding pin 9 rotates. Consequently, through the shoulder 8th no additional frictional heat is generated, but it merely ensures that through the shoulder 8th at the appropriate time, the required pressure is exerted on the material to be plasticized in the connection area. By doing that, the shoulder 8th During the friction stir welding process in a rotating sense "stuck" is both a higher speed of the welding pin 9 as well as a reduction of the through the shoulder 8th mediated process force possible, the latter in particular leads to a simplification of the system technology. In turn, the former results in a uniform temperature distribution over the entire thickness or the entire cross-section of the parts to be joined during the friction stir welding process 5 . 6 is guaranteed, so that they can be welded reliably and with high quality. The through the shoulder 8th otherwise caused frictional heat generation on the surface of the parts to be joined 5 . 6 is significantly reduced, which effectively prevents overheating on the surface.

According to an alternative embodiment of the friction stir tool according to the invention 2 can be dispensed with the molding. Then the direction towards the welding pin 9 facing side of the warehouse 10 as a shoulder. This is due to the reduced components a particularly simple embodiment. The function and operation of this alternative shoulder is the same as in the above-described, formed as a molded shoulder 8th ,

Another alternative embodiment of the molding allows to dispense with the bearing.

LIST OF REFERENCE NUMBERS

1

contraption

2

friction stir

3

fiber source

4

fiber

5

first workpiece

6

second workpiece

7

tool body

8th

shoulder

9

welding pin

10

storage

11

Through opening

12

connecting area

13

connecting line

14

forward movement

15

Rotation of the welding pin

16

Flow of the weld metal

17

plasticized fabric

18

welded seam

19

Object with welded seam

Claims (30)

Object ( 19 ) of at least one fiber-reinforced material with a welded seam ( 18 ), where one fiber ( 4 ) in the seam ( 18 ), characterized in that the fiber ( 4 ) extends almost the entire length of the seam and has a helical shape in the seam. Object ( 19 ) according to claim 1, characterized in that a plurality of fibers ( 4 ) in the seam ( 18 ) are arranged. Object ( 19 ) according to claim 2, characterized in that the fibers ( 4 ) are confused with each other. Object ( 19 ) according to one of claims 1 to 3, characterized in that the object ( 19 ) is a component of an aircraft or a motor vehicle. A method of friction stir comprising the steps of: - inserting a rotationally driven pin-shaped projection ( 9 ) in a workpiece area or in a connection area ( 12 ) of at least two adjoining continuous fiber reinforced workpieces ( 5 . 6 ) with a matrix material under rotating motion, - plasticizing the workpiece area or the connecting area ( 12 ) in at least one contact area ( 17 ) between the rotating projection ( 9 ) and the workpiece area or connecting area ( 12 ), and - introducing a fiber ( 4 ) in the plasticized area ( 17 ), whereby the fiber ( 4 ) by means of the Head Start ( 9 ) excited material flow of the matrix material of the workpieces ( 5 . 6 ) from the circulating plasticized area ( 17 ) and flow-dependent or flow-dependent in the plasticized region ( 17 ), and a seam ( 18 ) is provided with a longitudinal direction in which the fiber ( 4 ) has a helix shape extending along the longitudinal direction of the seam ( 18 ). Method according to claim 5, characterized in that a shoulder ( 8th ) on the workpiece area or connecting area ( 12 ) is applied under at least temporary pressurization, wherein during the projection ( 9 ) is in contact with the workpiece area or connecting area, the speed of rotation of the shoulder ( 8th ) n = 0. Method according to claim 5, characterized in that a shoulder ( 8th ) is applied to the workpiece area or connecting area under at least temporary pressurization, wherein during the projection ( 9 ) is in contact with the workpiece area or connecting area, the speed of rotation of the shoulder ( 8th ) greater than 0 and smaller than the rotational speed of the projection ( 9 ). Method according to one of claims 5 to 7, characterized in that the projection ( 9 ) in the workpiece area or connecting area ( 12 ) is moved linearly, the fiber ( 4 ) continuously into the plasticized area ( 17 ) is introduced. Method according to one of claims 5 to 8, characterized in that the projection ( 9 ) relative to the adjacent workpieces ( 5 . 6 ) along the connecting line ( 13 ) of the adjacent workpieces ( 5 . 6 ) is moved. Method according to one of claims 5 to 9, characterized in that the adjoining workpieces ( 5 . 6 ) relative to the projection ( 9 ) along the connecting line ( 13 ) of the adjacent workpieces ( 5 . 6 ) are moved. Friction stir tool ( 2 ) comprising a rotationally drivable tool body ( 7 ), at the drive end facing away from a shoulder ( 8th ) is provided, from which in the direction away from the drive end of the tool body ( 7 ) a rotatable, pin-shaped projection ( 9 ), which has a smaller diameter than the shoulder ( 8th ), wherein the shoulder ( 8th ) and the pin-shaped projection ( 9 ) are independently driven in rotation, characterized in that at least one passage opening ( 11 ) in the shoulder ( 8th ) next to the projection ( 9 ) is arranged, which in the direction away from the drive end of the tool body ( 7 ). Friction stir tool ( 2 ) according to claim 11, characterized in that the shoulder ( 8th ) is designed such that upon rotation of the pin-shaped projection ( 9 ) has a speed n = 0. Friction stir tool ( 2 ) according to claim 11 or claim 12, characterized in that the shoulder ( 8th ) by means of sliding or roller bearings ( 10 ) on the tool body ( 7 ) is stored. Friction stir tool ( 2 ) according to claim 13, characterized in that the shoulder ( 8th ) is a molding which is in the direction of projection ( 9 ) facing side of the sliding or rolling bearing ( 10 ) is arranged. Friction stir tool ( 2 ) according to claim 14, characterized in that an edge portion of the molding is angled such that it is the sliding or rolling bearing ( 10 ) at least partially surrounds. Friction stir tool ( 2 ) according to claim 14 or claim 15, characterized in that the molded part at least on its in the direction of projection ( 9 ) facing side is provided with a friction-reducing material. Friction stir tool ( 2 ) according to claim 11 or claim 12, characterized in that on the tool body ( 7 ) a sliding or rolling bearing ( 10 ) is arranged, whose at least in the direction of projection ( 9 ) side facing the shoulder ( 8th ). Friction stir tool ( 2 ) according to claim 17, characterized in that the projection ( 9 ) facing side of the sliding or rolling bearing ( 10 ) is provided with a friction-reducing material. Friction stir tool ( 2 ) according to one of claims 11 to 18, characterized in that the pin-shaped projection ( 9 ) in one piece with the tool body ( 7 ) is trained. Friction stir tool ( 2 ) according to one of claims 11 to 19, characterized in that the tool ( 2 ) is rotationally symmetrical. Friction stir tool ( 2 ) according to one of claims 11 to 20, characterized in that the passage opening ( 11 ) in the direction of the drive-away surface of the shoulder ( 8th ) expands. Friction stir tool ( 2 ) according to one of claims 11 to 21, characterized in that the passage opening ( 11 ) substantially perpendicular to the in the direction away from the drive surface of the shoulder ( 8th ). Friction stir tool ( 2 ) according to one of claims 11 to 22, characterized in that the passage opening ( 11 ) from the drive-facing surface of the shoulder ( 8th ) up to the one in the lead ( 9 ) facing away from the shoulder ( 8th ). Contraption ( 1 ) for friction stir, comprising a friction stir tool ( 2 ) according to one of claims 11 to 23, wherein the projection ( 9 ) in a workpiece area or a connection area ( 12 ) of at least two workpieces to be joined ( 5 . 6 ) is insertable under rotating movement, so that during its rotation in contact with the workpiece area or connecting area ( 12 ) the lead ( 9 ) this plasticized and plastified material (at least in the contact area) ( 17 ), characterized in that the device ( 1 ) a fiber source ( 3 ) and that a fiber ( 4 ) via the passage opening ( 11 ) in the shoulder ( 8th ) into the plasticized substance ( 17 ) is insertable. Contraption ( 1 ) according to claim 24, characterized in that the device ( 1 ) further comprising drive means, with which the device ( 1 ) under the rotary drive of the projection ( 9 ) can be performed linearly. Contraption ( 1 ) according to claim 24 or claim 25, characterized in that the shoulder ( 8th ) on the workpieces ( 5 . 6 ) outside the contact area between the projection ( 9 ) and the workpiece area or connecting area ( 12 ) can be applied. Use of the friction stir tool ( 2 ) according to one of claims 11 to 23 for welding fiber-reinforced plastics, fiber-reinforced metals or fiber-reinforced alloys. Use of the friction stir tool ( 2 ) according to one of claims 11 to 23 for welding two adjoining workpieces made of fiber-reinforced plastic, fiber-reinforced metal or fiber-reinforced alloys. Use of the device ( 1 ) according to one of claims 24 to 26 for welding fiber-reinforced plastics, fiber-reinforced metals or fiber-reinforced alloys. Use of the device ( 1 ) according to one of claims 24 to 26 for welding two adjoining workpieces made of fiber-reinforced plastic, fiber-reinforced metal or fiber-reinforced alloys.

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