FR3126634A1 - System and method for inertial friction welding with hot machining of the weld bead - Google Patents

Abstract

This friction welding system (1) of a first element (2) and a second element (3) of a turbomachine creating a weld bead (11) between the first element (2) and the second element (3) comprises a first holding tool (5) for the first element (2), a second holding tool (6) for the second element (3), and a device (15) for hot removal of the weld bead (11), the first holding tool (5) being able to enter into rotation around an axis of rotation (13). Figure for abstract: Fig 1

Description

System and method for inertial friction welding with hot machining of the weld bead

The present invention relates to the friction welding of two elements to be welded.

The present invention relates more particularly to the inertial friction welding of two elements and the hot machining of the weld bead created by the friction welding.

Prior techniques

Friction welding consists in assembling two elements by putting these two elements under pressure against each other and by setting them in motion relative to each other in such a way that a contact surface of the first element rubs on a contact surface of the second element. The movement is for example a rotational movement.

The friction then generates heat, sufficient to bring the constituent material of the elements into a malleable state in their region adjacent to the contact surfaces.

These regions are thus able to deform and weld together after the movement of one element relative to the other has stopped and after the cooling of the two elements, the latter then being welded.

During welding, the regions adjacent to the contact surfaces deform by expelling material at the ends of the contact surfaces of the first and second elements. This expelled material forms a weld bead.

In some cases, it is necessary to subsequently remove the weld bead in order to flatten the area to be welded between the first element and the second element.

However, the welding operation and the operation of removing the weld bead require the dismantling of the first and the second element between the two operations, leading to an extended manufacturing time. Indeed, it is necessary to geometrically readjust the first and the second elements in order to machine the weld bead properly. Finally, machining the weld bead on a cold and therefore rigid material is tedious and easily damages the tools used during machining.

The object of the present invention is therefore to overcome the aforementioned drawbacks and to simplify the removal of excess material when it is still hot.

The subject of the present invention is a friction welding system for a first element and a second element of a turbomachine creating a weld bead between the first element and the second element, the welding system comprising a first holding tool of the first element, a second tool for holding the second element, and a device for hot removal of the weld bead, the first holding tool being capable of entering into rotation about an axis of rotation.

Thus, the weld bead is removed quickly and easily, without the need to rework the welded elements at the output of the welding system.

Advantageously, the device for hot removal of the weld bead comprises an outer arm movable parallel and perpendicular to the axis of rotation of the first holding tool, the arm comprising at least one machining insert comprising at least one face intended to scrape the weld bead.

In one embodiment, the first and second members are hollow, and wherein the hot weld bead stripping device comprises an inner arm adapted to be introduced into the first and second members, the inner arm being movable parallel and perpendicular to the axis of rotation of the first holding tool, the internal arm comprising at least one machining insert comprising at least one face intended to scrape the weld bead.

Advantageously, the at least one machining insert is made of a material resistant to the high heat prevailing in the weld bead.

In a particular embodiment, the at least one face of the plate intended to scrape the weld bead is parallel to a plane comprising the axis of rotation of the first holding tool or is substantially perpendicular to a plane comprising the axis rotation of the first holding tool.

In one embodiment, the second holding tool is able to enter into rotation around the axis of rotation of the first holding tool.

The invention also relates to a method for welding a first element and a second element by friction, the method comprising the following steps:

• Positioning and alignment of the first and second elements respectively on a first holding tool and on a second holding tool of a welding system as defined above;
• Rotation of the first element by the first holding tool;
• Bringing the first and second elements into contact and holding them under pressure for their friction welding, said welding creating a weld bead;
• Elimination of the hot welding bead; And
• Stopping the rotation of the first element against the second element.

In one mode of implementation, the step of removing the weld bead is carried out before the step of stopping the rotation of the first element against the second element, the second element being rotated by the second tool at a speed different from the rotation of the first holding tool, the removal of the weld bead being carried out by scraping at least one face of a wafer parallel to a plane comprising the axis of rotation of the first holding tool .

In another mode of implementation, the step of removing the weld bead is carried out after the step of stopping the rotation of the first element against the second element, the removal of the weld bead being carried out by scraping at least one face of a wafer parallel to a plane comprising the axis of rotation of the first holding tool.

In another mode of implementation, the step of removing the weld bead is carried out after the step of stopping the rotation of the first element against the second element, the removal of the weld bead being carried out by scraping longitudinal of at least one face of a wafer substantially perpendicular to a plane comprising the axis of rotation of the first holding tool.

Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

is a schematic view of a welding system according to the invention and in a first embodiment;

is a schematic view of an embodiment of an outer end of an outer arm of a welding system according to the invention;

is a schematic view of a second embodiment of an outer end of an outer arm of a welding system according to the invention;

is a schematic view of an alternative embodiment of the an outer end of an outer arm of a welding system according to the invention;

is a schematic view of a welding system according to the invention and in another embodiment;

illustrates the different steps of the welding process according to the invention in one mode of implementation; And

illustrates the different steps of the welding process according to the invention in another mode of implementation.

Detailed description of at least one embodiment

We represented on the a system 1 for welding a first element 2 and a second element 3 by friction.

The welding system 1 comprises a first holding tool 5 for the first element 2 as well as a second holding tool 6 for the second element 3 intended to avoid any parasitic movement of the first and second elements 2 and 3 during welding. In particular, the first element 2 and the second element 3 are represented here by hollow tubes to be welded at their end at the level of their contact surface 7 to form a pipe. In addition, the first and the second elements 2 and 3 are intended to be welded at the level of a weld zone 8 in which the regions 10 adjacent to the contact surfaces 7 are located, these adjacent regions 10 being intended to become malleable with the heat of friction and from which the weld bead 11 to be removed emerges.

The first and the second holding tools 5 and 6 comprise jaws 12 able to hold the first element 2 and the second element 3 aligned facing each other. The first holding tool 5 comprises an axis of rotation 13 and is able to enter into rotation around this axis of rotation 13. The first holding tool 5 comprises for example a motor in order to be able to enter into rotation. Optionally, the second holding tool 6 is also capable of entering into rotation around the axis of rotation 13.

In the embodiment illustrated in , the axis of rotation 13 corresponds to the longitudinal axis of the first element 2 and of the second element 3, aligned in a direction Z.

The welding system 1 further comprises a device 15 for hot removal of the weld bead 11. Thus, the weld bead 11 does not have time to cool and is removed while its material is still malleable. The device for hot removal of the weld bead comprises a base 16. The base 16 is for example located at one end of the first element 2 against the first holding tool 5. Alternatively, the base is located at one end of the second element 3 against the second holding tool 6.

The device 15 for hot removal of the weld bead 11 comprises an outer arm 17 to the first element 2 and to the second element 3. The outer arm 17 is movable parallel to the axis of rotation 13, in a direction Z. The outer arm 17 is also movable perpendicularly to the axis of rotation 13 in the direction Y. The outer arm 17 comprises an outer end 18 capable of being positioned facing the weld zone 8. The outer end 18 comprises for example one or more plates 20 machining.

Optionally, the device 15 for hot removal of the weld bead comprises an arm 21 also called internal arm 21. The arm 21 is a deployable arm and adapted to be introduced inside the first element 2 and the second element 3. This embodiment is particularly suitable when welding hollow elements as illustrated in , where the first and second elements 2 and 3 are tubes in which the inner arm 21 can be introduced in order to remove the weld bead 11 from the inside.

The internal arm 21 is movable parallel to the axis of rotation 13, along a direction Z. The internal arm 21 is also movable perpendicularly to the axis of rotation 13 along the direction Y. The internal arm 21 comprises an internal end 22 adapted to be positioned facing the welding zone. The inner end 22 comprises for example one or more machining inserts 20.

The movement parallel to the axis of rotation 13 of the outer arm 17 makes it possible to adjust the longitudinal position of the inner end 22 at the level of the weld zone 8. In addition, during welding, the first or the second element 2 or 3 can be made more malleable than the other element on a region 10 adjacent to the contact surfaces 7 and the weld zone 8 can then translate slightly in the direction Z. The same is true for the internal arm 21, the optionally.

The movement perpendicular to the axis of rotation 13 of the outer arm 17 makes it possible to bring the outer end 18 of the weld bead 11 closer or apart. The same is true for the inner arm 21 and the inner end 22, the optionally.

We represented on the an embodiment of an outer end 18 of an outer arm 17, the end comprising a pad 20. Equivalently, the can relate to an internal end 22. The wafer 20 is for example of triangular section. The wafer 20 comprises two faces 23 intended to scrape the weld bead 11 when the wafer 20 is placed at the level of the weld bead 11. The faces 23 are each parallel to a plane comprising the axis of rotation 13. The two faces 23 make it possible to scrape and remove the weld bead 11 regardless of the direction of rotation of the first and second elements 2 and 3.

Plate 20 or each face 23 of plate 20 is made of a material resistant to the high heat present in and close to weld bead 11 at the time of welding. A resistant material is, for example, ceramic. Plate 20 is substantially the length of weld bead 11.

According to an alternative embodiment of an outer end 18 of an outer arm 17, shown in , the outer end 18 comprises two plates 20 parallel to each other. Equivalently, the can relate to an inner end 22. The pads 20 are for example of triangular section. Each plate 20 comprises a face 23 intended to scrape the weld bead 11 when the plates 20 are placed at the level of the weld bead 11, the two faces 23 being substantially opposite. The faces 23 are each parallel to a plane comprising the axis of rotation 13. The two faces 23 make it possible to scrape and remove the weld bead 11 regardless of the direction of rotation of the first and second elements 2 and 3.

Plates 20 or each face 23 of plates 20 are made of a material resistant to the high heat present in and close to weld bead 11 at the time of welding. A resistant material is, for example, ceramic. Plates 20 are substantially the length of weld bead 11.

In a variant of the embodiment of the , illustrated in , the plates 20 are parallel and offset so as to each cover a part of the weld bead 11 in an implementation mode where the first and the second holding tools 5 and 6 rotate in opposite directions. Plates 20 are then substantially the length of half of weld bead 11.

In another embodiment of the welding system shown in , the outer 18 and/or inner 22 ends of the outer arm 17 and/or of the inner arm 21 each comprise a plate 20 whose face 23 intended to scrape the weld bead 11 is substantially perpendicular to a plane comprising the axis of rotation 13. In this embodiment, a translational movement in the Z direction of the outer 17 and inner 21 arms is necessary in order to scrape the weld bead 11.

We represented on the the steps of an embodiment of a method of welding the first element 2 with the second element 3.

In one mode of implementation, the welding system shown in .

A step 31 of positioning and aligning the first and second elements 2 and 3 respectively on the first and second holding tools 5 and 6 is carried out using the jaws 12.

Then, a step 32 of rotating the first element 2 is performed using the first holding tool 5 rotated by a motor (not shown). Alternatively, by effect of symmetry, it is the second element 3 which can be rotated.

Next, a step 33 of bringing the first and second elements into contact and maintaining pressure against each other is carried out for friction welding. In this step 33, the contact surfaces 7 rub against each other and heat the adjacent regions 10 so that the material becomes malleable and allows the welding of the first and second elements 2 and 3. The malleable material however creates the weld bead 11 that needs to be removed for aesthetic and practical reasons.

During the next step 34, the hot weld bead 11 is removed. In particular, the weld bead 11 is removed parallel to step 33 of welding. To do this, the first and second holding tools 5 and 6 are rotated and the machining plate(s) 20 are approached to the weld bead 11 being formed in order to scrape said weld bead 11 throughout the welding. The first and second holding tools 5 and 6 are rotated, while the plate or plates 20 remain stationary, in order to move the weld bead 11 and scrape it over its entire length. In particular, the first and second holding tools 5 and 6 are rotated at different speeds so that friction welding is effective, while allowing the plate(s) 20 to scrape the weld bead 11.

In the embodiment of the , the first and second holding tools 5 and 6 are for example rotated in opposite directions.

In this mode of implementation, the plate or plates 20 comprise one or more faces 23 intended to scrape the weld bead 11, the face or faces being parallel to a plane comprising the axis of rotation 13.

Finally, a step 35 of stopping the rotation of the first element 2 against the second element 3 is carried out. The material cools and the welding secures the first element 2 to the second element 3.

In another mode of implementation illustrated in and using the welding system of the , the step 34 of removing the weld bead 11 is carried out after the step of stopping the rotation of the first element 2. In particular, the removal of the weld bead 11 takes place once the weld has secured the first element 2 and the second element 3, the weld bead 11 remaining hot and easily machinable for its removal.

In this mode of implementation, the plate or plates 20 comprise one or more faces 23 intended to scrape the weld bead 11, the face or faces 23 being parallel to a plane comprising the axis of rotation 13.

In addition, the first and the second elements 2 and 3 being joined together, it is not necessary for the second holding tool 6 to drive the rotation of the first and second elements 2 and 3. The first holding tool 5 ensures the rotation of the first and second elements 2 and 3 during the removal of the weld bead 11.

In a variant of the mode of implementation illustrated in , the welding system according to the embodiment shown in .

In this mode of implementation, the step 34 of removing the weld bead 11 is carried out after the step of stopping the rotation of the first element 2. In particular, the removal of the weld bead 11 performed once the weld has joined the first element 2 and the second element 3, the weld bead 11 remaining hot and easily machinable for its removal.

In this mode of implementation, the plate or plates 20 comprise one or more faces 23 intended to scrape the weld bead 11, the face or faces 23 being substantially perpendicular to a plane comprising the axis of rotation 13. In particular, this mode of implementation comprises round trips in the direction Z of the wafers 20 using the removal device 15 in order to scrape the weld bead 11. After each round trip, the first holding tool 5 performs a slight rotation to position the pad(s) 20 opposite a new portion of weld bead 11 to be removed.

In addition, the first and the second elements 2 and 3 being joined together, it is not necessary for the second holding tool 6 to drive the rotation of the first and second elements 2 and 3. The first holding tool 5 ensures the rotation of the first and second elements 2 and 3 during the removal of the weld bead 11.

Claims (10)

Friction welding system (1) of a first element (2) and a second element (3) of a turbomachine, creating a weld bead (11) between the first element (2) and the second element (3) , characterized in that it comprises a first holding tool (5) for the first element (2), a second holding tool (6) for the second element (3), and a device (15) for hot removal of the bead weld (11), the first holding tool (5) being adapted to enter into rotation around an axis of rotation (13). System according to claim 1, in which the device (15) for hot removing the weld bead (11) comprises an external arm (17) movable parallel and perpendicular to the axis of rotation (13) of the first holding tool ( 5), the outer arm (17) comprising at least one machining insert (20) comprising at least one face (23) intended to scrape the weld bead (11). System according to one of Claims 1 and 2, in which the first and second elements (2; 3) are hollow, and in which the device (15) for hot removing the weld bead (11) comprises an internal arm (21 ) adapted to be introduced into the first and second elements (2; 3), the internal arm (21) being movable parallel and perpendicular to the axis of rotation (13) of the first holding tool (5), the internal arm ( 21) comprising at least one machining insert (20) comprising at least one face (23) intended to scrape the weld bead (11). System according to one of Claims 2 and 3, in which the at least one machining insert (20) is made of a material resistant to the high heat prevailing in the weld bead (11). System according to any one of Claims 2 to 4, in which the at least one face (23) of the plate (20) intended to scrape the weld bead (11) is parallel to a plane comprising the axis of rotation (13) of the first holding tool (5) or is substantially perpendicular to a plane comprising the axis of rotation (13) of the first holding tool (5). System according to any one of Claims 1 to 5, in which the second holding tool (6) is capable of entering into rotation about the axis of rotation (13) of the first holding tool. Method of welding a first element (2) and a second element (3) by friction, characterized in that it comprises the following steps:

• Positioning and alignment (step 31) of the first and second elements (2; 3) respectively on a first holding tool (5) and on a second holding tool (6) of a welding system (1) according to the any of claims 1 to 6;
• Rotation (step 32) of the first element (2) by the first holding tool (5);
• Bringing into contact and maintaining pressure (step 33) of the first and second elements (2; 3) for their friction welding, said welding creating a weld bead (11);
• Removal (step 34) of the weld bead (11) hot; And
• Stopping the rotation (step 35) of the first element (2) against the second element (3).

Method according to claim 7, in which the step (34) of eliminating the weld bead (11) is carried out before the step (35) of stopping the rotation of the first element (2) against the second element (3), the second element (3) being rotated by the second holding tool (6) at a speed different from the rotation of the first holding tool (5), the removal of the weld bead (11) being carried out by scraping at least one face (23) of a wafer (20) parallel to a plane comprising the axis of rotation (13) of the first holding tool (5). Method according to claim 7, in which the step (34) of removing the weld bead (11) is carried out after the step (35) of stopping the rotation of the first element (2) against the second element (3), the removal of the weld bead (11) being carried out by scraping at least one face (23) of a plate (20) parallel to a plane comprising the axis of rotation (13) of the first tooling of maintenance. Method according to claim 7, in which the step (34) of removing the weld bead (11) is carried out after the step (35) of stopping the rotation of the first element (2) against the second element (3), the removal of the weld bead (11) being carried out by longitudinal scraping of at least one face (23) of a wafer (20) substantially perpendicular to a plane comprising the axis of rotation (13) of the first holding tool.