Arc welding system, method for welding parts using such a system, and range of accessories for such an arc welding system

Abstract

The present application relates to an arc welding system comprising a mobile base comprising at least one magnetic element (10) that is able to produce, using magnetic attraction, a force for holding the base on the surface over which it is moving, at least one arc welding torch (4), preferably a standard arc welding torch such as is used for MAG or MIG welding, mounted on the base and connected to a welding station (2), a flux dispensing assembly (15), removably mounted on the base in order to submerge the arc with the flux, this assembly (15) comprising a flux reservoir, at least one flux dispensing nozzle, and at least one flux suction nozzle (23).

Description

[0001] ARC WELDING SYSTEM, METHOD FOR WELDING WORKPIECES USING SUCH A SYSTEM, AND RANGE OF ACCESSORIES FOR SUCH AN ARC WELDING SYSTEM

[0002] Technical field

[0003] The present invention relates to the welding of parts, in particular for the automotive, aeronautical, civil engineering or naval industries.

[0004] The invention relates in particular to mobile submerged arc welding (SAW) systems.

[0005] Prior art

[0006] To weld parts, especially metal parts, it is known to use an arc welding system.

[0007] Conventional arc welding processes, such as MAG or MIG, are so-called open arc processes that produce fumes and UV radiation, requiring special precautions to protect the operator. In these processes, the filler metal is supplied in the form of welding wire, constituting a consumable electrode, being unwound from a spool. An inert gas is sprayed onto the weld zone to protect the weld pool.

[0008] It is known to perform a so-called submerged arc welding. In this technology, the arc is submerged under a solid flux in powder form. Solid flux welding offers the advantage of reducing, in particular of completely eliminating, the emission of fumes, of having an arc at least partially, in particular completely obscured by the flux, in particular not visible, and little sensitive to air currents.

[0009] This technology is suitable for welding in closed or open environments, for example outdoors in a shipyard. It produces a high-quality weld with high productivity.

[0010] Submerged arc welding is mechanized, but this mechanization is often simple and robust. Indeed, known installations for performing submerged arc welding are mounted on a jib or a generally heavy trolley, the weight of which contributes to the trolley's stabilization. They typically weigh more than 40 kg and require handling equipment to transport them, thus complicating their use. The process is limited to flat or cornice welding positions. In addition, these installations are specific to solid submerged arc welding and are only suitable for this type of welding. For example, with such an installation, it is not possible to perform sheet metal tack welding. It is therefore often necessary to have, in addition to a submerged arc installation, another welding installation, for example MIG or MAG. Thus, the investment required to acquire a submerged arc welding installation is relatively high, which can limit its use.

[0011] These trolley-type installations require the installation of guides for guidance due to the weight of the assembly, which further complicates the operation.

[0012] In addition, the time required to carry out the welding, i.e. positioning the heavy carriage, the guides, moving the carriage, removing the guides and removing the carriage, is significant, thus reducing production efficiency.

[0013] There is a need to overcome all or part of the disadvantages of the state of the art and in particular to have a solid flux welding system which is simple to use, if desired portable by an operator, quick to set up, while limiting the dedicated investment to be made and which is capable of producing a good quality weld. Presentation of the invention

[0014] The present invention meets this need thanks to, according to one of its aspects, an arc welding system, comprising:

[0015] A mobile base, comprising at least one magnetic element capable of producing by magnetic attraction a holding force of the base on a surface on which it moves, at least one arc welding torch, preferably standard as used for MAG or MIG welding, mounted on the base and connected to a welding station, a flux distribution assembly, removably mounted on the base for submerging the arc with the flux, this assembly comprising: o a flux reservoir, o at least one flux distribution nozzle, and o at least one flux suction nozzle.

[0016] The system can thus perform, depending on the presence or absence of the distribution assembly, or whether it is operating or not, a non-submerged or submerged weld.

[0017] The welding torch, the magnetic element and the flux distribution assembly are moved by the base during the welding operation. The system according to the invention makes it possible to have a relatively light submerged arc welding system, in comparison with the prior art, without losing stability thanks to the use of the magnetic element. Thus, thanks to the invention, it is possible to carry out good quality submerged arc welding, while having a system that is easy to use and handle.

[0018] The system also allows non-submerged welding, i.e. open arc welding, to be carried out by deactivating the distribution assembly, or even by dismantling it from the base. Thus, the system according to the invention allows submerged or non-submerged welding to be carried out, depending on requirements, with the same equipment, thus reducing the need for investment and the need for operator training.

[0019] The mobile part of the system may in particular weigh less than 30 kg, preferably less than 20 kg, for example 15 kg, avoiding the use of a handling system such as a hoist or the like. The holding force provided by the magnetic element may be greater than 10 kg, in particular greater than 25 kg. The magnetic element may comprise one or more rare earth permanent magnets.

[0020] The welding torch is connected to a welding station, which provides the electric current needed to generate the arc.

[0021] Finally, the removable nature of the flux distribution assembly allows it to be offered as an accessory to the base, the latter being able to be used in combination with a different accessory, or without an accessory, to carry out, for example, MAG or MIG type welding. Thus, the investment required for a user who already has the base, for example to carry out another type of process, or a welding station, for example a standard one, in particular a MIG or MAG station for another application, to be able to carry out submerged arc welding, is lower, since only the acquisition of the flux distribution assembly is then necessary.

[0022] The welding system can be used on parts positioned horizontally or forming an angle with the horizontal of less than 15°. The welding system can be used to weld parts forming a cornice between them.

[0023] Welding torch

[0024] The welding torch can be removably mounted on the base.

[0025] The torch may be configured to deliver, during welding, a welding material, in particular a welding wire. The torch may be configured to deliver, during welding, a wire electrode, this wire electrode having in particular a diameter of between 0.2 mm and 2 mm, for example 1.6 mm or 2 mm.

[0026] The welding torch can be a standard torch suitable for MAG or MIG welding.

[0027] The system may include one, two, or even more welding torches. Using two welding torches can allow the use of smaller diameter welding wires, but combine their effects. For example, each torch uses a 1.6mm diameter welding wire, which is significantly smaller than the welding wires conventionally used in known submerged arc welding installations, typically 4 to 8mm.

[0028] Mobile base

[0029] The base can be a mobile trolley, a gantry or a rotating column.

[0030] The base may comprise a bracket on which at least certain constituent elements of the flow distribution assembly, for example the flow reservoir, are removably fixed.

[0031] The stem can also be used to attach other system components to the base.

[0032] The base, in particular the carriage, may have wheels and / or tracks, in particular motorized ones, allowing it to move along the parts to be welded. The carriage may be moved by rolling over the parts to be welded, or on at least one guide rail, or even on a rack. The carriage may be guided, if necessary, by resting on one of the parts to be welded, in particular when this is a stiffener.

[0033] The base, including the trolley, may have four motorized wheels, each wheel being able to be controlled independently of the others in order to steer the trolley in the desired direction.

[0034] The base, in particular the trolley, may include at least one, or even two, sets of wheels, in particular a right set and a left set, independently motorized.

[0035] The use of wheels allows for rail-free guidance and therefore limited installation logistics.

[0036] The base may include a gripping element allowing the operator to grasp and carry the base, for example with one hand. The base may include a power supply system, in particular a battery. The use of a battery eliminates the need for an external and bulky power cable.

[0037] When the parts to be welded are arranged vertically and the weld joint horizontally, called the "cornice position" or "2G" or "PC" position, the base can move horizontally. In this case, the welding torch, the suction nozzle and the distribution nozzle can be located in the lower part of the system, with the flux container positioned in the upper part of the system.

[0038] The system may include, in particular near the flux distribution and suction nozzles, an accessory allowing the flux to be retained in the welding zone, in particular when the parts are in the cornice position.

[0039] The accessory may be a platform comprising a conveyor belt, preferably moving with the same linear speed as the base. Preferably, the face of the conveyor belt intended to retain the flux moves in a direction opposite to the welding direction, in particular at an absolute speed identical to the absolute welding speed so that the face of the conveyor belt intended to retain the flux is fixed relative to the parts to be welded and therefore to the weld.

[0040] The base may include an arm for attaching, in particular in a removable and adjustable manner, the welding torch. The base, in particular the arm, may, where appropriate, allow the accessory for retaining the flux to be attached, in particular in a removable and adjustable manner.

[0041] The position of the arm can be adjustable along several axes, notably in translation along one, two or three axes, and / or in rotation.

[0042] The base can carry various components necessary for the operation of the system, including at least one rechargeable battery.

[0043] The welding station may not be carried by the base, being only connected by a hose to the welding torch.

[0044] Control and guidance

[0045] The system may include a control unit programmed to perform welding autonomously and / or semi-autonomously.

[0046] By "autonomously" we mean that the system is capable of performing the weld without the intervention of an operator. By "semi-autonomously" we mean that the system is capable of performing the weld under the supervision of an operator, the operator being able to transmit orders to the system in order to correct certain parameters of movement of the base or the weld.

[0047] The control unit can include any processor, for example microcontroller and the interfaces to interact with the environment of the latter, for example sensor(s), power stage for controlling the motors, HMI, transmitter / receiver to exchange with a wireless remote control.

[0048] The control unit may optionally be removably mounted on the system, particularly on the base. In this case, the system may include a receiving base with a series of connectors for mounting the control unit on the base.

[0049] The system may include a remote control, in particular a wireless one, preferably a remote control, allowing an operator to remotely control the movement of the base relative to the parts to be welded, in particular the speed of advance of the base, the direction of movement of the base, and / or welding parameters.

[0050] The remote control can also be configured to allow control of the position of the arm carrying the welding torch.

[0051] The system may include a transceiver communicating with the remote control, included in the control unit or independent.

[0052] The system may comprise a guide means, in particular comprising at least one guide rail. This guide rail may be fixed magnetically or otherwise to one of the parts.

[0053] The system may include a guide laser forming a visual reference on the parts to be welded, in particular positioned on the edge of the chamfer of a welding cornice, to guide the base.

[0054] The system may include a profilometer, in particular a laser, measuring the profile of the parts to be welded upstream of the welding torch in the direction of movement of the latter.

[0055] Welding station

[0056] Preferably, the welding station is a standard welding station usable for an open arc welding operation. By "standard welding station" is meant a welding station commonly used for open arc welding operations, for example MAG or MIG type, not flooded under flux. The use of a standard welding station makes it possible to significantly reduce the cost of the system, this type of station being commonly found commercially.

[0057] The welding station, also called a generator, can be fixed relative to the parts to be welded during the movement of the base.

[0058] Alternatively, the station may be moved during welding relative to the parts, in particular occasionally as the welding progresses. For example, the welding station is placed in a first location, and the base is moved a certain distance without moving the welding station, the hose connecting the welding torch to the welding station being deployed during this operation. Then, the welding station may be brought to a second location, which brings it closer to the base, and the welding operation continued.

[0059] Alternatively, the station itself can be equipped with wheels and be moved continuously during welding, for example pulled by the base.

[0060] The welding station may include a reel of welding material. The welding material may be sent from the welding station to the welding torch through a guide, present within the aforementioned hose, for example.

[0061] The welding station can be a MIG (Metal Inert Gas) and / or MAG (Metal Active Gas) station, whose protective gas flow is deactivated when using the flux.

[0062] The welding station may include a ground clamp configured to be positioned on at least one of the parts to be welded.

[0063] The welding station may include a control panel for controlling welding parameters, including electrical voltage, electrical current and / or feed rate of the welding material.

[0064] Removable flow distribution assembly

[0065] The flux may contain manganese oxides, complex silicates of lime and / or alumina, particularly in powder form.

[0066] The flux can be a solid or molten flux.

[0067] The flow may be an agglomerated flow.

[0068] The flux can be basic or acidic.

[0069] Preferably, the flux is a solid flux. The solid flux may comprise a powder of calibrated and homogeneous size.

[0070] The flux drawn in by the suction nozzle can be returned to the flux tank, preferably cleaned and / or screened.

[0071] The circulation of the flow in the flow distribution assembly can be ensured by compressed air, in particular coming from a compressed air supply to which the assembly is connected.

[0072] The removable assembly can be configured to deliver a linear flow rate of between 0.1cm 3 / mm and 20cm 3 / mm.

[0073] The assembly may include means for taking the flux from the flux reservoir and ensuring its circulation to the welding zone, as well as suction and return to the reservoir. These means may include a separator, for example a cyclonic separator, to separate the flux particles returned to the reservoir from the carrier gas, and a system for injecting air into the reservoir to drive the flux particles towards the welding zone. Carrier air may be returned to the atmosphere after filtration.

[0074] Welding process

[0075] The invention also relates, according to another of its aspects, in combination with the above, to a method of welding parts using a system according to the invention, as defined above, in which the base is set in motion relative to the parts to be welded, and, when the base is in motion: the flux distribution assembly deposits flux on the parts to be welded upstream of the torch, the welding torch produces an arc, the latter being embedded in the flux thus deposited,

[0076] The flow distribution assembly recovers excess flow downstream of the torch by suction.

[0077] When the base is moving, the welding torch, distribution nozzle and suction nozzle can be aligned in the direction of its movement.

[0078] The welding station can be fixed relative to the parts to be welded.

[0079] Range of accessories

[0080] The invention also relates, according to another of its aspects, independently or in combination with the above, to a range of accessories for an arc welding system comprising a base configured to move along parts to be welded, this range comprising: a flux distribution assembly, configured to be removably fixed to the base, in order to allow submerged arc welding to be carried out, at least one welding torch, in particular a standard one as used for MAG or MIG welding, which can be removably mounted on the base.

[0081] This range can be completed by the base itself, and by the remote control used to control it.

[0082] Brief description of the drawings

[0083] The invention may be better understood by reading the detailed description which follows, a non-limiting example of its implementation, and by examining the attached drawing, in which

[0084] [Fig 1] Figure 1 schematically and partially represents an example of a system according to the invention,

[0085] [Fig 2] Figure 2 shows an elevation of a detail of the system,

[0086] [Fig 3] Figure 3 illustrates in perspective the production of a submerged arc weld,

[0087] [Fig 4] Figure 4 illustrates, in side view and schematically, an example of a system for a cornice weld, and

[0088] [Fig 5] Figure 5 illustrates, in perspective and schematically, an example of a system for a cornice weld.

[0089] Detailed description

[0090] In the remainder of the description, identical elements or elements with identical functions bear the same reference sign.

[0091] In the figures, the actual proportions have not always been respected, for the sake of clarity.

[0092] Figures 1 to 3 illustrate an example of an arc welding system 1 according to the invention for welding metal parts P, for example steel sheets or a stiffener on a steel sheet. The system comprises a standard welding station 2, for example a MIG generator whose function of sending a flow of protective gas has been switched off.

[0093] The welding station 2 is connected by a hose 3 to a welding torch 4, for example a torch 4 used for MIG welding.

[0094] The welding station 2 may include a control panel 5 for adjusting the electrical voltage, the electrical intensity and the feed speed of the welding material, in this example a wire electrode, for example 1.6 mm in diameter. The wire electrode may be unwound from a reel present on the welding station 2 and guided to the torch 4 by a conduit of the flexible hose 3.

[0095] The torch 4 may include a trigger 7 allowing the operator to manually trigger the formation of the electric arc and the unwinding of the wire electrode.

[0096] System 1 comprises a carriage 6 which is arranged to move along the parts to be welded and which carries the torch 4.

[0097] This carriage 6 rests for example by motorized wheels 8, for example four in number, on at least one of the parts to be welded, but in a variant comprises tracks or other drive means, and can where appropriate circulate on one or more rails installed on the parts or in their vicinity, or even on a rack.

[0098] The carriage 6 carries at least one magnetic element 10 in the form of one or more rare earth permanent magnets, which produces by magnetic attraction a force F for holding the carriage 6 on the surface on which it has been placed.

[0099] The magnetic element 10 advantageously produces a magnetic force F of intensity greater than the weight of the trolley 6 and its equipment. The force F is for example of intensity greater than or equal to 10 kg, the mass of the trolley and its equipment being advantageously less than or equal to 30 kg, better still 25 kg.

[0100] The carriage 6 carries a solid flux distribution assembly 15, allowing the electric arc generated by the torch 4 to be submerged under the flux.

[0101] This assembly 15 is removably attached to the carriage 6, in order to allow the carriage to be used without it, for example to carry out conventional open arc welding, particularly of the MAG or MIG type.

[0102] The assembly 15 comprises a solid flow reservoir 16, which may be surmounted for example by a separator and / or filter 18. The assembly 15 is connected to a compressed air supply 20, for example in the form of a hose.

[0103] This supply 20 can be connected to a venturi 21, arranged in the circuit 22 returning the flow to the separator 18.

[0104] The venturi 21 makes it possible to create a vacuum in the return circuit 22 and a suction of the flow particles from the inlet 23 of a suction nozzle.

[0105] The separator 18 makes it possible to separate the solid particles from the flow of the carrier gas, which can be released into the atmosphere as illustrated by the arrows, after passing through a filter.

[0106] The solid flow particles can, after separation from the carrier gas, fall into the reservoir 16.

[0107] The latter may have a truncated cone shape in the lower part, in order to channel the flow particles towards an outlet port connected by a conduit 29 to a distribution nozzle 24.

[0108] The reservoir 16 may comprise a tube 26 which plunges into it and makes it possible to bring the compressed air close to the outlet port, in order to cause the flow of the flux particles and their entrainment in the conduit 29 to the distribution nozzle 24.

[0109] The system 1 may include a bracket 30, which supports the tank 16 and allows it to be fixed to the carriage 6.

[0110] This bracket 30 is fixed for example by one or more screws on a corresponding support provided on the carriage 6.

[0111] The torch 4 can be carried by an arm 31 which allows, for example, it to be positioned precisely and with the desired orientation relative to the carriage 6.

[0112] Likewise, the flow distribution nozzles 24 and suction nozzles 23 can be mounted with the possibility of adjustment in position, if necessary.

[0113] During use of the system 1, a circulation of solid flux can be established between the nozzles 23 and 24, to maintain a cloud of solid flux 35 at the level of the arc generated by the torch 4, and thus carry out submerged arc welding.

[0114] To use the system 1, if the user already has the carriage 6 used without the assembly 15 to carry out MAG or MIG type welding, he simply has to mount the assembly 15 on the carriage 6 and connect it to the compressed air supply 20. The system 1 is advantageously controlled by a remote control 40, as illustrated in FIG. 1, which makes it possible, for example, to adjust various operating parameters, such as the feed speed of the carriage, the direction of movement, to correct the trajectory, or even the orientation of the torch 4 relative to the carriage 6.

[0115] Figure 3 shows the carriage 6 moving along the welding path.

[0116] It can be seen that the solid flow distribution nozzle 24 can be arranged upstream relative to the torch 4, relative to the direction of advancement of the carriage, while the suction nozzle 23 is arranged downstream.

[0117] It can also be seen that the distribution nozzle 24 can be closer to the torch 4 than the suction nozzle 23.

[0118] The trolley 6 may comprise a removable control unit 60, which contains at least part of the electronics necessary for controlling the wheel motors, and more generally, for the operation of the system.

[0119] This control unit 60 can be received in a corresponding base of the trolley, provided with electrical connectors allowing power supply and signal exchange.

[0120] The trolley 6 may also include a battery, which may also be removably mounted thereon.

[0121] In Figure 3, it can be seen that the carriage 6 can be equipped at the front with a laser pointer forming a visual mark on the parts P to be welded on the edge of the chamfer of the cornice 70 between the parts P.

[0122] The movement of the carriage 6 can be carried out, if necessary, according to information delivered by a sensor such as for example a profilometer arranged to acquire the profile of the parts to be welded, a camera, a laser pointer 38 or any other means making it possible to detect and locate the cornice 70, in order for example to precisely follow the cornice 70 where the weld 71 must be carried out. This movement can be carried out automatically, or semi-automatically, the operator retaining for example the possibility of modifying the trajectory at any time.

[0123] Figures 4 and 5 illustrate a variant of the system for welding parts

[0124] P arranged vertically with a cornice 70 horizontally, called “cornice position” or “2G” position or “PC”. In figures 4 and 5, part of system 1 has not been shown, for the sake of clarity.

[0125] In this case, the carriage can move horizontally, for example on an adjacent platform. Thus, the torch 4, the suction nozzle 23 and the distribution nozzle 24 are, as in the previous example, in the lower part of the system 1, the flux reservoir 16 being positioned in the upper part of the system 1.

[0126] The system 1 may comprise, near the flux distribution nozzles 24 and suction nozzles 23, an accessory 100 making it possible to retain the flux 35 in the welding zone.

[0127] As illustrated in Figure 4(a), the accessory may include an L-shaped platform.

[0128] The accessory 100 is fixed on the arm 31.

[0129] As illustrated in Figures 4(b) and 5, the accessory 100 may comprise a conveyor belt 101 moving with the same linear speed as the carriage.

[0130] The face 102 of the conveyor belt 101 intended to retain the flux 35 moves in a direction T opposite to the welding direction D, at an absolute speed identical to the absolute welding speed so that the face 102 is fixed relative to the parts P to be welded and therefore of the cornice 70.

[0131] In this example, the belt 101 rotates around two axes 105, which may in particular be motorized.

[0132] Of course, the invention is not limited to the examples which have just been described.

[0133] For example, two torches 4 can be mounted on the carriage, which operate simultaneously, for example, both submerged arc torches, the assembly being in this case adapted to distribute the solid flux to each of the torches individually or not. These two torches can be installed side by side or one behind the other, or even offset, depending on the configuration of the joint to be welded.

[0134] For example, the system may comprise a guide means comprising at least one guide rail, for example a rail parallel to the cornice.

Claims

Demands 1. Arc welding system (1), comprising: A mobile base (6), comprising at least one magnetic element (10) capable of producing by magnetic attraction a force to hold the base on the surface on which it moves, at least one arc welding torch (4), preferably standard such as used for MAG or MIG welding, mounted on the base (6) and connected to a welding station (2), a flux distribution assembly (15), removably mounted on the base to submerge the arc with the flux, this assembly comprising: o a flux reservoir (16), o at least one flux distribution nozzle (24), and o at least one flux suction nozzle (23).

2. System according to claim 1, the holding force provided by the magnetic element (10) being greater than 10 kg, preferably greater than or equal to 25 kg.

3. System according to any one of claims 1 and 2, the welding station (2) being a standard welding station usable for an open arc welding operation, in particular of the MAG or MIG type.

4. System according to the preceding claim, the welding torch (4) being removably mounted on the base (6).

5. System according to any one of the preceding claims, the torch (4) being configured to cut, during welding, an electrode wire having a diameter between 0.2 mm and 2 mm, preferably 1.6 mm or 2 mm.

6. System according to any one of the preceding claims, the welding torch (4) being a standard torch usable for MAG or MIG welding.

7. System according to any one of the preceding claims, the base (6) comprising wheels (8), in particular motorized, enabling its movement along the parts to be welded.

8. System according to any one of the preceding claims, comprising a guiding means, including in particular at least one guide rail.

9. System according to any one of the preceding claims, comprising a remote control, in particular wireless, preferably a remote control (40), enabling an operator to remotely control the movement of the base relative to the parts to be welded, in particular the feed speed of the base, the direction of movement of the base, and / or welding parameters.

10. System according to any one of the preceding claims, wherein the welding station (2) is fixed relative to the parts to be welded during the movement of the base (6).

11. System according to any one of the preceding claims, wherein the circulation of the flow in the assembly (15) is ensured by compressed air, in particular from a compressed air supply (20) to which the assembly (15) is connected.

12. System according to any one of the preceding claims, comprising an accessory (100) for retaining the flux (35) in the weld zone, particularly when the parts are in a cornice position.

13. System according to the preceding claim, wherein the accessory (100) is a platform comprising a conveyor belt (101).

14. A method for welding parts using a system (1) as defined in any one of the preceding claims, wherein the base (6) is moved relative to the parts to be welded, and, when the base is moving: the flux distribution assembly (15) distributes flux onto the parts to be welded, the welding torch produces an arc, the latter being immersed in the flux thus distributed, the flux distribution assembly (15) recovers the flux by suction.

15. A range of accessories for an arc welding system comprising a base (6) configured to move along parts to be welded, this range comprising: A flux distribution assembly (15), configured to be removably attached to the base (6), to enable submerged arc welding, at least one welding torch (4) being able to be removably mounted on the base (6).

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