FRICTION STIR WELDING PROCESS

Abstract

A method of friction-stir welding, FSW, a joint J, for example a T joint J, between a first workpiece W1 and a second workpiece W2 is described. The method comprises: arranging the first workpiece W1 and the second workpiece W2; performing a first pass P1 of FSW of the joint J by moving therealong a first tool 10, comprising a first probe 100 rotating in a first rotational direction RD1 and at least partially inserted into the first workpiece W1 and/or into the second workpiece W2 to a first depth D1, in a first movement direction MD1 defining a first line L1, on a first side S1 of the joint J, thereby providing a first welded region WR1; and performing a second pass P2 of FSW of the joint J by moving therealong a second tool 20, comprising a second probe 200 rotating in a second rotational direction RD2 and at least partially inserted into the first workpiece W1 and/or into the second workpiece W2 to a second depth D2, in a second movement direction MD2 defining a second line L2, on a second side S2 of the joint J, thereby providing a second welded region WR2; wherein the first tool 10 and the second tool 20 are mutually opposed; and wherein performing the first pass P1 of FSW and performing the second pass P2 of FSW are at least partially concurrent.

Claims

1. A method of friction-stir welding, FSW, a T joint between a first workpiece and a second workpiece, the method comprising: arranging the first workpiece and the second workpiece; performing a first pass of FSW of the joint by moving therealong a first tool, the first tool comprising a first probe rotating in a first rotational direction and inserted into the first workpiece and/or into the second workpiece to a first depth, in a first movement direction defining a first line, on a first side of the joint, thereby providing a first welded region; and performing a second pass of FSW of the joint by moving therealong a second tool, the second tool comprising a second probe rotating in a second rotational direction and inserted into the first workpiece and/or into the second workpiece to a second depth, in a second movement direction defining a second line, on a second side of the joint, thereby providing a second welded region; wherein the first tool and the second tool are mutually opposed, wherein the first tool and the second tool are angled with respect to the first workpiece and the second workpiece, wherein the angle is in a range from 15° to 75°; wherein performing the first pass of FSW and performing the second pass of FSW are concurrent; and wherein the first tool and the second tool comprise a stationary shoulder comprising a chamfered leading edge and a radiused trailing edge.

2. The method according to claim 1, wherein the chamfered leading edge has a chamfer angle in a range from 40° to 50° and/or wherein the chamfered leading edge has a length in a range from 10 mm to 20 mm.

3. The method according to claim 1, wherein the first movement direction and the second movement direction are mutually aligned.

4. The method according to claim 1, wherein the first tool and the second tool are mutually offset in the first movement direction and in the second movement direction, respectively and/or wherein the first probe and the second probe are mutually spaced apart, for example by a spacing transverse, preferably orthogonal, to the joint, the first line and/or the second line, so as to avoid collision or interference of the first probe and the second probe.

5. The method according to claim 1, wherein the first workpiece comprises a male member, wherein the second workpiece comprises a corresponding female member and wherein arranging the first workpiece and the second workpiece comprises receiving the male member in the female member.

6. The method according to claim 1, wherein the first workpiece comprises a first fillet and wherein performing the first pass of FSW of the joint comprises at least partially inserting the first probe into the first fillet.

7. The method according to claim 1, wherein the first rotational direction and the second rotational direction are opposed.

8. The method according to any p claim 1, wherein the first line and the second line are mutually spaced apart.

9. The method according to claim 1, comprising applying a clamping force on the first workpiece and/or the second workpiece, for example while performing the first pass of FSW and/or the second pass of FSW.

10. The method according to c claim 1, wherein the radiused trailing edge has a radius in a range from 10 mm to 20 mm.

11. The method according to claim 1, wherein the first workpiece and/or the second workpiece comprises an aluminium alloy, a titanium alloy, a copper alloy, and/or a steel.

12. The method according to claim 1, wherein the first workpiece and/or the second workpiece has a thickness in a range from 0.5 mm to 25 mm.

13. A method of manufacturing a component, comprising the method of friction-stir welding, FSW, a T joint between a first workpiece and a second workpiece, according to claim 1.

14. A friction stir welding, FSW, tool comprising a probe rotatable in a rotational direction, wherein the tool comprises a stationary shoulder comprising a chamfered leading edge and/or a radiused trailing edge.

15. The tool according to claim 14, wherein the chamfered leading edge has a chamfer angle in a range from 40° to 50°, wherein the chamfered leading edge has a length in a range from 10 mm to 20 mm and/or wherein the radiused trailing edge has a radius in a range from 10 mm to 20 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0115] For a better understanding of the invention, and to show how exemplary embodiments of the same may be brought into effect, reference will be made, by way of example only, to the accompanying diagrammatic Figures, in which:

[0116] FIGS. 1 to 3 schematically depict a method of friction stir welding;

[0117] FIG. 4 schematically depicts joint configurations for FSW: (a) square butt; (b) edge butt; (c) T butt joint; (d) lap joint; (e) multiple lap joint; (f) T lap joint; and (g) fillet joint;

[0118] FIGS. 5A, 5B and 5C schematically depict a method of friction stir welding, according to an exemplary embodiment; and

[0119] FIG. 6 schematically depicts a tool, according to an exemplary embodiment.

DETAILED DESCRIPTION

[0120] FIGS. 1 to 3 schematically depict a method of friction stir welding.

[0121] As shown in FIG. 1, an anticlockwise rotating probe of a FSW tool is inserted at the start (touchdown) into a butt joint between first and second workpieces, to a first depth, such that a shoulder of the tool is in contact with the first and second workpieces.

[0122] As shown in FIG. 2, the tool is moving in the direction of movement of the tool, as shown, providing a weld zone. An advancing side of the weld is where the direction of movement of the tool, as shown, and the direction of rotation of the probe are in the same general directions. A retreating side of the weld is where the direction of movement of the tool and the direction of rotation of the probe are in the opposite general directions.

[0123] As shown in FIG. 3, the tool is withdrawn at the stop, resulting in an exit hole.

[0124] Suitable probes for FSW include (a) a straight cylindrical probe; (b) a threaded cylindrical probe; (c) a tapered cylindrical probe; (d) a square probe; (e) a triangle probe; (f) a whorl (TM) probe; (g) a MX triflute (TM) probe; (h) a flared triflute (TM) probe; (i) an A-skew (TM) probe; and (j) a re-stir (TM) probe.

[0125] FIG. 4 schematically depicts joint configurations for FSW: (a) square butt; (b) edge butt; (c) T butt joint; (d) lap joint; (e) multiple lap joint; (f) T lap joint; and (g) fillet joint.

[0126] FIGS. 5A, 5B and 5C schematically depict a method of friction stir welding, according to an exemplary embodiment. Briefly, FIG. 5A shows a setup of a joint J before FSW, FIG. 5B shows the joint J during FSW and FIG. 5C shows the joint J after FSW.

[0127] The method is of friction-stir welding, FSW, a joint J, for example a T joint J, between a first workpiece W1 and a second workpiece W2. The method comprises: arranging the first workpiece W1 and the second workpiece W2; performing a first pass P1 of FSW of the joint J by moving therealong a first tool 10, comprising a first probe 100 rotating in a first rotational direction RD1 and inserted into the first workpiece W1 and/or into the second workpiece W2 to a first depth D1, in a first movement direction MD1 (not shown; for example, into the page) defining a first line L1 (not shown), on a first side S1 of the joint J, thereby providing a first welded region WR1 (not shown); and performing a second pass P2 of FSW of the joint J by moving therealong a second tool 20, comprising a second probe 200 rotating in a second rotational direction RD2 and inserted into the first workpiece W1 and/or into the second workpiece W2 to a second depth D2, in a second movement direction MD2 (not shown; for example, into the page) defining a second line L2 (now shown), on a second side S2 of the joint J, thereby providing a second welded region WR2 (not shown); wherein the first tool 10 and the second tool 20 are mutually opposed; and wherein performing the first pass P1 of FSW and performing the second pass P2 of FSW are concurrent.

[0128] In this example, the first workpiece W1 is a stringer (having a T-shaped cross-sectional profile) located in a skin, particularly in a rectangular slot (corresponding to a lower end of the stringer) formed therein, the slot having bevelled edges (i.e. a first fillet and a second fillet) extending away therefrom. A pair of stationary shoulder tools (i.e. the first tool 10 and the second tool 20) support the stringer from either side, with friction stir tool pins (i.e. the first probe 100 and the second probe 200) driven through the respective tool shoulders into the bevelled edges of the skin. The first probe 100 and the second probe 200 are mutually offset into the page to avoid a clash but support blocks have sufficient reach to provide local support. Particularly, in the case where the two opposing probes are partially off-set (into/out of the page) so as to avoid a clash of the pins then the probe on one side of the joint is “opposed” by the block on the other and so the blocks must have sufficient length (in and out of the page) to provide this support. This is what is meant by “reach”.

[0129] In this example, the joint J is a T joint. In this example, a position of the FSW, for example of the first pass P1 of FSW and/or of the second pass P2 of FSW, is flat.

[0130] In this example, the method comprises providing the first workpiece W1 and the second workpiece W2. In this example, providing the first workpiece W1 comprises including, by machining, a male member M (e.g. a tongue) therein and providing the second workpiece W2 comprises including, by machining, a corresponding female member F (e.g. a groove or rebate) therein. In this example, arranging the first workpiece W1 and the second workpiece W2 comprises receiving the male member M in the female member F.

[0131] In this example the first workpiece W1 comprises a male member M and the second workpiece W2 comprises a corresponding female member F and arranging the first workpiece W1 and the second workpiece W2 comprises receiving the male member M in the female member F.

[0132] In this example, the first rotational direction RD1 is anticlockwise, as viewed from above the first tool 10. In this example, the first movement direction MD1 is a first translational direction. In this example, the first line L1 is or linear. In this example, the first line L1 is parallel to the joint J.

[0133] In this example, performing the first pass P1 of FSW comprises inserting the first probe 100 to the first depth D1, resulting in a first entry hole ENH1 (not shown). In this example, the method comprises moving the first tool 10 in the first movement direction MD1 from the first entry hole ENH1 towards and/or to a first exit hole EXH1 (not shown), for example at a first speed, while applying a first axial force F1.

[0134] In this example, performing the first pass P1 of FSW comprises withdrawing at least partially the first probe 100. In this example, withdrawing at least partially the first probe 100 comprises gradually, for example linearly as a function of distance and/or time, withdrawing at least partially the first probe 100.

[0135] In this example, withdrawing at least partially the first probe 100 comprises withdrawing the first probe 100 by an amount of at least 50%, preferably at least 75%, more preferably at least 90% of the first depth D1. In this example, withdrawing at least partially the first probe 100 comprises withdrawing the first probe 100 from the first depth D1 while moving the first tool 10 in the first movement direction MD1. In this example, performing the first pass P1 of FSW comprises fully withdrawing the first probe 100, thereby resulting in the first exit hole EXH1.

[0136] In this example, performing the first pass P1 of FSW comprises inserting the first probe 100 into the first workpiece W1, for example, to the first depth D1, resulting in a first entry hole ENH1, moving the first probe 100 in the first movement direction MD1, thereby providing the first welded region WR1 including ‘healing’ the first entry hole ENH1, and then fully withdrawing the first probe 100, thereby resulting in a first exit hole EXH1.

[0137] In this example, the second line L2 is parallel to the joint J. In this example, the second line L2 is parallel to the first line L1. In this example, the first line L1 and the second line L2 are mutually spaced apart.

[0138] In this example, the second rotational direction RD2 is clockwise, as viewed from above the second tool 20. In this example, the second movement direction MD2 is a second translational direction. In this example, the second line L2 is linear. In this example, the first rotational direction RD1 and the second rotational direction RD2 are the same rotational direction, for example both anticlockwise.

[0139] In this example, performing the second pass P2 of FSW comprises inserting the second probe 200 to the second depth D2, thereby providing the second welded region WR2. In this example, the seconded welded region extends along a first distance of the second line L2. In this example, the first distance of the second line L2 extends fully along the first distance of the first line L1.

[0140] In this example, inserting the second probe 200 to the second depth D2 results in a second entry hole ENH2. In this example, the method comprises moving the second tool 20 in the second movement direction MD2 from the second entry hole ENH2 towards and/or to a second exit hole EXH2, for example at a second speed, while applying a second axial force F2. In this example, the second speed is equal to the first speed.

[0141] In this example, performing the second pass P2 of FSW comprises optionally withdrawing at least partially the second probe 200. In this example, withdrawing at least partially the second probe 200 comprises gradually, for example linearly as a function of distance and/or time, withdrawing at least partially the second probe 200. In this example, withdrawing at least partially the second probe 200 comprises withdrawing the second probe 200 by an amount of at least 50%, preferably at least 75%, more preferably at least 90% of the second depth D2. In this example, withdrawing at least partially the second probe 200 comprises withdrawing the second probe 200 from the second depth D2 while moving the second tool 20 in the second movement direction MD2.

[0142] In this example, the first depth D1 and the second depth D2 are similar, for example the same.

[0143] In this example, performing the second pass P2 of FSW comprises fully withdrawing the second probe 200, thereby resulting in the second exit hole EXH2.

[0144] In this example, the first probe 100 and the second probe 200 are mutually offset in the first movement direction MD1 and in the second movement direction MD2, respectively. In this example, the first probe 100 and the second probe 200 are mutually offset, for example by an offset or a displacement along the joint J, the first line and/or the second line, so as to avoid collision or interference of the first probe 100 and the second probe 200. In this example, the offset is in a range from 1 mm to 50 mm.

[0145] In this example, performing the first pass P1 of FSW and performing the second pass P2 of FSW are concurrent, for example, wherein the first probe 100 and the second probe 200 are mutually offset in the first movement direction MD1 and in the second movement direction MD2, respectively, so as to avoid collision or interference of the first probe 100 and the second probe 200.

[0146] In this example, the first welded region WR1 and the second welded region WR2 intersect. In this example, the first welded region WR1 and the second welded region WR2 intersect by an amount in a range from 1% to 50%.

[0147] In this example, the first movement direction MD1 and the second movement direction MD2 are the same direction. In this example, the first movement direction MD1 and the second movement direction MD2 are mutually aligned.

[0148] In this example, the first workpiece W1 comprises a first fillet and performing the first pass P1 of FSW of the joint J comprises inserting the first probe 100 into the first fillet.

[0149] In this example, performing the second pass P2 of FSW comprises inserting the second probe 200 into the first workpiece W1, for example, to the second depth D2, resulting in a second entry hole ENH2, moving the second probe 200 in the second movement direction MD2, thereby providing the second welded region WR2, before optionally partially withdrawing the second probe 200, and then fully withdrawing the second probe 200, thereby resulting in the second exit hole EXH2.

[0150] In this example, the first line L1 and the second line L2 are mutually spaced apart, for example by a predetermined spacing, whereby the first welded region WR1 and the second welded region WR2 at least partially overlap. In this example, the predetermined spacing is at most a first width of the first welded region WR1, a second width of the second welded region WR2 and/or a mean of the first width and the second width. In this example, the first welded region WR1 and the second welded region WR2 at least partially overlap by an amount in a range from 10% to 90% by the first width of the first welded region WR1, the second width of the second welded region WR2 and/or the mean of the first width and the second width.

[0151] In this example, the first tool 10 and the second tool 20 is angled with respect to the first workpiece W1 and the second workpiece W2, wherein the angle is about 45°. In this example, the first tool 10 and the second tool 20 bisect an angle between the first workpiece W1 and the second workpiece W2.

[0152] In this example, the method comprises applying a clamping force F3 on the first workpiece W1 and/or the second workpiece W2, for example while performing the first pass of FSW and/or the second pass of FSW. In this example, applying the clamping force F3 on the first workpiece W1 and/or the second workpiece W2 comprises applying the clamping force F3 on the first workpiece W1 and/or the second workpiece W2 using a dynamic (i.e. moving) support, such as a roller arranged to roll on the first workpiece W1, for example moving in the first movement direction MD1 and/or the same movement direction in line with the first tool 10 and/or the second tool 20, such as at the same speed.

[0153] In this example, the first tool 10 and/or the second tool 20 comprises a stationary shoulder, as described above. In this example, the first probe 100 comprises and/or is a straight cylindrical probe, a threaded cylindrical probe, a tapered cylindrical probe, a square probe, a triangle probe, a whorl probe, a MX triflute probe, a flared triflute probe, a A-skew probe and/or a re-stir probe. Other probes are known.

[0154] In this example, the first workpiece W1 and the second workpiece W2 comprises a 2XXX aluminium alloy.

[0155] In this example, the first workpiece W1 and/or the second workpiece W2 has a thickness in a range from 0.5 mm to 25 mm, preferably in a range from 1.6 mm to 20 mm, more preferably in a range from 2 mm to 15 mm. In this example, the first workpiece W1 is a skin of an aircraft and the second workpiece W2 is a spar or a rib.

[0156] FIGS. 5A, 5B and 5C also schematically depict an apparatus for friction stir welding, according to an exemplary embodiment.

[0157] The apparatus is for friction-stir welding, FSW, a joint J, preferably a T joint J, between a first workpiece W1 and a second workpiece W2, the apparatus comprising:

[0158] a first tool 10, comprising a first probe 100 rotatable in a first rotational direction RD1 and at least partially insertable into the first workpiece W1 and/or into the second workpiece W2 to a first depth D1, moveable in a first movement direction MD1 defining a first line L1, for performing a first pass P1 of FSW of the joint J by moving therealong thereby providing a first welded region WR1; and

[0159] a second tool 20, comprising a second probe 200 rotatable in a first rotational direction RD1 and at least partially insertable into the first workpiece W1 and/or into the second workpiece W2 to a second depth D2, moveable in a second movement direction MD2 defining a second line L2, for performing a second pass P2 of FSW by moving therealong thereby providing a second welded region WR2;

[0160] wherein the first tool 10 and the second tool 20 are mutually opposed; and

[0161] wherein the apparatus is configured to perform the first pass P1 of FSW and to perform the second pass P2 of FSW are at least partially concurrently.

[0162] FIG. 6 schematically depicts a tool, for example the first tool 10 and/or the second tool 20, according to an exemplary embodiment.

[0163] In this example, the tool 10 comprises a stationary shoulder 11.

[0164] In this example, the stationary shoulder 11 comprises a chamfered leading edge 110 and a radiused trailing edge 120. In this example, the chamfered leading edge 110 has a chamfer angle of 45°. In this example, the chamfered leading edge 110 has a length of 15 mm×15 mm. In this example, the radiused trailing edge 120 has a radius of 15 mm.

[0165] Although a preferred embodiment has been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims and as described above.

[0166] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0167] All of the features disclosed in this specification (including any accompanying claims and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at most some of such features and/or steps are mutually exclusive.

[0168] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0169] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.