FR3012759A3 - SYSTEM AND METHOD FOR WELDING AND / OR RECHARGING WITH ADDITIONAL WIRE - Google Patents

Abstract

The invention relates to a system (1) for welding and / or reloading a workpiece (30) with a consumable electrode (10), comprising a welding torch (2) of the MIG / MAG type, a first feed of wire (3). for the consumable electrode (10) in the torch, and a second feed of wire for bringing an additional wire (20) to a welding and / or charging location. According to the invention, the second wire feed is arranged with respect to the welding torch (2) so as to establish an angle (α) between the additional wire (20) and the consumable electrode (10) included between 30 and 70 degrees, and, in use, a point of impact of the consumable electrode (10) and additional wire (20) concomitant on the surface (30a) of the workpiece (30). Welding and / or reloading process with associated additional wire.

Description

The present invention relates to welding techniques, and in particular to a system for welding and / or reloading a workpiece and a process for welding and / or reloading MIG / MAG of a workpiece with a consumable electrode and with additional wire of a workpiece according to the preamble of claims 1 and 13 respectively. The present invention also relates to an installation for welding and / or reloading a part, this installation comprising a system according to the present invention. MIG / MAG ("Metal Inert Gas" or "MAG") welding is a process that allows not only the welding of at least one part but also the reloading of part (s) for repair or deposit of a coating. This method uses the creation of an arc between a fuse electrode, usually a wire, which is generally brought continuously into the melting zone by means of the arc. From US2,681,970, which is based on the preamble of claims 1 and 13 respectively, there is known a welding method employing a MIG / MAG torch with fusible electrode and use of an additional wire provided by an additional wire feed. The additional wire feed is electrically independent of the welding generator and is inclined to allow an additional wire feed substantially horizontal with respect to the workpiece. No details are provided in this document regarding the point of impact of the additional wire vis-à-vis the consumable electrode and the surface of the workpiece. US 2,870,323 discloses a method similar to the preceding document, wherein the arrival of the supply of the additional wire is substantially vertical with respect to the workpiece. The system described in this document also allows room reloading. The additional wire makes it possible to add additional metallurgical elements to the solder or the refill created, which can not be effectively integrated into the consumable electrode, in order to obtain a composition of the welded joint or optimal reloading with respect to terms of use. In this document, the point of impact of the additional wire on the surface of the workpiece is located at the rear of the consumable electrode. It is also known in the field of submerged arc welding, see for example the document US2003 / 0052110, to use an additional wire for welding in order to increase the rate of deposition of melt while controlling the composition of this deposited material. The inclination of the additional wire feed is controlled so as to prevent the additional wire from striking the workpiece, with a value of this angle vis-à-vis the workpiece less than 60 degrees.

It is also known, in view of increasing the melt deposition rate, to employ a tandem MIG / MAG welding system, using two electrode wires to create a single welding bath. Commercial systems typically employ two welding generators and two wire feeders to bring the two wires into two separate torches or a dedicated torch. The two wires are unwound through two separate contact tubes. The gas shield should extend over a wider area to protect the larger welding bath from atmospheric contamination. Figure 1 illustrates the operation of this variant of MIG / MAG welding. The magnetic interaction between the two arcs can affect the stability of the process. The present invention aims to overcome all or part of the disadvantages mentioned above. In particular, the present invention aims to increase the rate of deposition of molten material in a welding process and / or reloading and this at constant energy, and relates to a system for welding and / or reloading a part with a consumable electrode, an installation comprising such a system and a MIG / MAG welding and / or recharging process of a consumable electrode part, as defined in claims 1, 12 and 13.

The solution according to the invention is then a system for welding and / or reloading a workpiece with a consumable electrode, comprising a welding torch of the MIG / MAG type, a first feed of wire for the consumable electrode in the torch, and a second supply of wire to bring a wire to the welding and / or recharging place, wherein this second feed of wire is arranged vis-à-vis the welding torch so as to establish an angle a between the wire and the consumable electrode between 30 and 70 degrees, and, in use, a point of impact of the consumable electrode and the concomitant wire on the surface of the workpiece. The positioning of the concomitant impact point of the consumable electrode and the wire on the part to be welded and / or recharged and the angle between the wire and the consumable electrode comprised between 30 and 70 degrees, makes it possible to increase the rate substantially constant energy deposition rate, (ie with the same energy level employed by a system for soldering and / or recharging without additional thread). This is due to the fact that the additional wire inclined in this way 30 passes through the hottest areas of the electric arc. This crossing of the hot zones of the electric arc causes a preheating effect of the additional wire, thus implying an increased efficiency with respect to a horizontal inlet, that is to say the angle - as defined in the present invention - greater than 70 degrees, or too vertical, that is, the angle less than 30 degrees. The process according to the invention makes it possible to achieve the same advantages.

According to particular embodiments of the invention, the system may comprise the one or more construction arrangements and / or one or more of the following additional features: the angle between the consumable electrode and the additional wire is between 30 and 50 degrees, preferably, the angle is set at 50 degrees, - this second supply of additional wire is independent of the torch, and / or this second supply of additional wire and / or the additional wire is independent (e) of an electric power generator for welding, the system further comprises a member for adjusting the position and / or the angular orientation of the second supply of additional wire with respect to the consumable electrode and / or the torch, this in order to optimize the deposition rate depending on the application envisaged, in particular according to the materials of the part and the son in the presence, - the adjustment member connects the second supply additional wire to the torch, - in use, the second additional wire feed is positioned, relative to the direction of welding and / or reloading, at the front or rear of the electric arc created between consumable electrode and the surface of the workpiece, - a third supply of additional wire is arranged in the system, and, preferably, is located opposite the second supply of additional wire vis-à-vis the longitudinal axis of the consumable electrode, the precision on said concomitance between the additional wire, the consumable electrode and the surface of the part in all of the planes perpendicular to the surface of the part is preferably obtained by the precision inherent to the control member included in the system, less than 1 mm, preferably less than 0.5 mm, and even more preferably less than 0.25 mm, the system comprises a device for heating the additional wire (s) - the positioning of the contact tube of the torch, into which the consumable electrode is brought, is situated between 10 and 20 mm of the surface of the workpiece, preferably between 13 and 17 mm, and more particularly at a distance of 15 mm. In another aspect, the invention relates to an installation for welding and / or reloading a part characterized in that this installation comprises a welding system and / or reloading according to the invention. Furthermore, the invention also relates to a method for MIG / MAG welding and / or recharging of a consumable electrode part comprising the following steps: positioning a welding torch with a first feed of wire for the consumable electrode and a second supply of additional wire to the welding and / or charging location, - establishing an electric arc between the consumable electrode and the surface of the part, characterized by the following step: - arranging the second feed of wire in a manner establishing an angle α between the additional wire and the consumable electrode of between 30 and 70 degrees, and a point of impact of the consumable electrode and the additional wire concomitant on the surface of the workpiece. According to particular embodiments of the method according to the invention, the latter comprises the following construction arrangements and / or additional steps: the step of arranging the second additional wire feed is performed before the positioning step of the torch and the second supply of additional wire, the transfer rate of the material of the consumable electrode has a level of energy sufficient to ensure droplet transfer in free flight, and preferably a transfer of drops. in spray mode or in pulsed mode, the electric arc existing between the consumable electrode and the part is protected by a flow of gas protecting against the atmosphere delivered by the torch, through a gas inlet, preferably said gas stream contains at least one inert compound preferably selected from helium and argon, preferably at least 80% by volume, and optionally a minor oxidizing chemical actin selected from oxygen (02) and carbon dioxide (CO2). Depending on the applications envisaged, in particular the material of the part, the flow of gas contains approximately 82% Vol of argon and 18% Vol of CO2, or the flow of gas containing approximately 98% Vol of argon and 2% Vol of CO2 . The industrial applications of the present invention are: - chamfer filling, since an increased deposition rate per pass leads to a lower number of filling passes, - the reloading of a piece, in English "cladding" Since the surface of a workpiece can be covered with a lower total number of passes, - thin sheet welding, ie. plates having a thickness of less than 6 mm, and more particularly less than 3 mm, by lowering the energy received by said sheet, thereby reducing the deformation of the sheet due to residual stresses. The invention will be better understood with the aid of the following description of particular exemplary embodiments and the following figures: FIG. 1 describes a tandem MIG / MAG welding system of the prior art, FIG. FIG. 2 describes a system for welding and / or reloading of the MIG / MAG type in accordance with one embodiment of the present invention; FIG. 3 shows an application of the invention to reloading a piece of generally cylindrical shape, and FIG. 4 describes different arrangement configurations between the fuse electrode, the wire and the part, according to one embodiment of the present invention and comparative configurations. FIG. 2 represents a system 1 for welding and / or recharging at least one part 30 according to the invention. This system 1 is integrable in an installation, not illustrated, for welding and / or recharging, and this in a configuration, preferably semi automatic or automatic, depending on the industrial applications envisaged.

The system 1 comprises, according to the invention, a welding torch 2 of the MIG / MAG type, with, in known manner, a first wire feed 10, comprising a passage 3 of generally circular shape, preferably a contact tube 3, integrated in the torch 2. The torch 2 comprises by its use for welding / reloading MIG / MAG, a gas inlet 4 for welding / reloading, this arrival can be located on an outer wall of said torch 2, as in the example illustrating the invention in Figure 2. The torch 2 will be electrically connected to a generator 4 of electrical power to provide energy for performing welding operations and / or reloading. In the example illustrated in Figure 2, but not essential in the context of the present invention, the positive terminal 4a of said generator 4 is connected to the torch 2, through a wire guide 5, integrated into the nozzle 6 of said torch 2, and the negative terminal 4b of said generator 4 is connected to the workpiece 30. In FIG. 2, the first feed 3 of wire 10 makes it possible to bring an electrode to the welding / recharging place of the workpiece 30. consumable 10. Between this consumable electrode 10 and the part 30 will be created, during welding / reloading operations, an electric arc 40 thanks to the electrical power supplied by the generator 4 which will cause the melting of the piece 30 and the electrode consumable 10. The consumable electrode 10 is stored in a container, the latter generally being in the form of a coil 11 on which is wound the consumable electrode 10. During welding / reloading operations, the electrode electrode 10 nsommable 10 is unwound from this coil 11 by a drive motor 12 and is introduced into the feed passage 3 of the torch 2 and to the place of welding / reloading. According to the system according to the invention (FIG. 2), a second supply of additional wire 20 is arranged next to the torch 2 MIG / MAG. This second supply of additional wire 20 comprises, in a manner similar to the supply of the consumable electrode 10, a container for storing this additional wire 20, the latter being generally in the form of a coil 21 on which this coil is wound. wire 20. During the welding / reloading operations, the additional wire 20 is unwound from this coil 21 by a drive motor 22 and is introduced into the feed passage of a guide 23 of generally cylindrical shape, and is directed to the place of welding / reloading. According to the present invention, this second wire feed 20 is arranged with respect to the welding torch 2 so as to establish an angle α between the consumable electrode 10 and the additional wire 20 between 30 and 70 degrees. In addition, the meeting point P between the consumable electrode 10 and the wire 20 is arranged such that the latter is concomitant with the surface 30a of the part 30, as indicated in FIG. 4a. The combination of these two settings in the welding configuration and / or reloading according to the present invention can increase the deposition rate of a welding process and / or reloading and this with a constant energy. The second supply of additional wire 20 may be independent of the torch 2. Thus, there is the absence of any mechanical connection of the arm, plate or any similar mechanical assembly, physically connecting this second supply of additional wire 20 to the torch 2.

In this configuration, the second supply of additional wire 20 is connected by another device to the welding / recharging installation, not shown in FIG. 2, in order to ensure a positional relationship between the torch 2 and the second feed of additional wire 20 when carrying out a welding and / or reloading operation according to the present invention.

Particularly advantageously, a member for adjusting the position and / or the angular orientation of the second additional wire feed 20 with respect to the consumable electrode 10 can be used, in order to be able to obtain, for each application welding and / or special reloading, an optimal melt deposition rate depending on the materials in the presence, part 30, wire (s) 20, consumable electrode 10, .... This adjusting member can, according to a characteristic advantageous but not essential for the system according to the invention, include a mechanism to ensure a relative displacement along each of the three perpendicular directions X, Y and Z (see Figure 2 for the definition of these directions X, Y and Z vis-à- screw of the system according to the invention) and an angular orientation the second supply of additional wire 20 in the plane XZ as shown in FIG. 2. The technology on which the construction will be based one of such a member for adjusting the position and / or the angular orientation of the second wire feed 20 with respect to the consumable electrode 10 is selected in connection with the level of precision to be achieved at the level of the concomitance . So depending on the level of precision sought, ie. from 1 to 0.25 mm in terms of positioning, the technology to be used will not be identical, but selected so as to guarantee the desired level, and this from a simple worm system with gaming retrofit device or not, system using servomotors, ... The second supply of additional wire and / or the additional wire 20 is / are independent (s) of the generator 4 of electrical power. Thus there is a total absence of electrical connection between this additional wire supply and / or the additional wire 20 with one of the positive terminals 4a and 4b of said negative generator 4. In this particularly advantageous configuration of the invention, the wire additional is not electrically powered and does not interfere in the creation of the electric arc created between the consumable electrode 10 and the part 30 during welding and / or reloading operations.

In order to further increase the rate of deposition of material used constant energy, a third feed wire may be added to the system described in Figure 2. This third feed wire, not shown in Figure 2, will be preferably positioned and oriented identically vis-à-vis the torch 2, i.e. the same angle θ and the same concomitance point P as the second supply of additional wire, but opposite the torch 2 vis-à-vis the longitudinal axis of the consumable electrode 10. An additional variant of the The invention described above consists in using a heating device, and more particularly a preheating device, of the additional wire 20. This heating / preheating device makes it possible to bring more metal into the melted zone by giving priority to the quantity of material deposited. , and is particularly advantageous in the operations of reloading and / or filling of the chamfer in the cords of large welds by volume. This heating or preheating device can be based on the principle of the Joule effect, and can be integrated in the guide 23 of the second additional wire supply 20 or be placed at any point along the path of this additional wire. 20, between the coil 21 and the end of this additional wire 20 before it enters the region of the arc 40. FIG. 2 represents either a welding operation of a part 30 with another part (not shown on said FIG. Figure 2), ie a reloading operation of a part 30, according to the present invention. The steps of the welding and / or reloading process according to the present invention are as follows: - positioning a welding torch 2 with a first feed of wire 3 for the consumable electrode 10 and a second supply of additional wire for the wire additional to the welding and / or charging location, - establish an electric arc between the consumable electrode 10 and the surface 30a of the workpiece 30 - arrange the second supply of additional wire 20 so as to establish an angle θ between the additional wire 20 and the consumable electrode 10 between 30 and 70 degrees, and a point of impact of the consumable electrode 10 and the additional wire 20 concomitant on the surface 30a of the part 30 The execution of the step d arrangement of the additional wire 20 will preferably be performed before the step of positioning the torch 2 and the second additional wire supply 20, in order to simplify the adjustment of the concomitant point in The consumable electrode 10, the additional wire 20 and the surface 30a of the workpiece 30. Preferably, but not essential to the present invention, the positioning and / or the angular orientation of the second supply of additional wire 20 in FIG. the set of planes perpendicular to the surface 30a of the part 30 will be made to obtain a precision on the point of concomitance of these three characteristics less than 1 mm, preferably less than 0.5 mm , and even more particularly, less than 0.25 mm. In the case where the system 1 according to the invention includes a member for adjusting this positioning and / or orientation of the second supply of additional wire 20 with respect to the welding torch 2, this member will be selected so as to enable to reach the level of accuracy / tolerance required and the position and / or orientation adjustment will be implemented by said position adjustment member and / or angular orientation. The position of the additional wire feed 20 during the welding and / or reloading operations can be either at the front of the torch 2 relative to the direction 100 of relative displacement between the torch, the second feed of additional wire 20 and the piece 30, which is at the rear of the torch 2 relative to the direction 100 of relative displacement between the torch, the second supply of additional wire 20 and the piece 30. The preferred positioning of the second additional wire feed 20 relative to the moving torch, in order to obtain a maximum deposition rate, for a configuration of the system comprising only one wire, is the forward position, as illustrated in FIG. Results in terms of deposition rate, whatever the configuration concerned, are achieved when the angle a is between 30 and 50 degrees. This angular orientation, associated with the precise concomitance of the consumable electrode 10 and the additional wire 20 on the surface 30a of the part 30, makes it possible to obtain an increase in the deposition rate of 30% compared to a MIG welding configuration. MAG without additional wire 20. The choice of the angle, while maintaining this precise concomitance of the consumable electrode 10 and the additional wire 20 on the surface 30a of the part 30, is made according to the application, That is, welding a workpiece 30 or reloading a workpiece 30. For example, an additional wire feed 20 oriented at an angle θ of 50 degrees provides slightly less additional wire 20 but less cools the bath only an additional wire feed 20 oriented at an angle of 30 degrees. This results in the morphology of the welding bead by better wetting and a less attenuated penetration. The operating mode of the electric power generator 4 for welding and / or recharging is selected, in particular through the current levels, the feed rate of the consumable electrode and the additional wire or wires, depending on the configuration. of the welding and / or reloading system adopted for the intended application. Advantageously, the operating speed of said generator 4 is regulated, always through the current levels, the feed rate of the consumable electrode 10 and the additional wire (s) 20, so as to allow a transfer regime drops of material of the consumable electrode 10 in free flight. Preferably this free-flight drop transfer mode then corresponds either to a transfer of drops in spray mode or to a drop transfer in pulsed mode. The welding operations in the context of the invention may be performed semi-automatically or completely automatically. The supply, positioning and fixing of the part 30 on a work plane included in the installation for welding and / or reloading is carried out before the establishment of the electric arc between the consumable electrode 10 and the surface 30a of the part 30. But this step of supplying, positioning and fixing the part 30 on said working plane of the installation may be implemented before or after the arrangement of the second supply of additional wire 20.

When the system 1 comprises a third supply of additional thread 40, the operations of arrangement of the position and / or inclination of the third feed of thread 40 are identical to that carried out for the second supply of additional thread 20 and can be implementation before or after the setting operation of the second supply of additional wire 20, and therefore also be placed at any time in the welding process and / or reloading envisaged, but always before the start of welding and / or reloading itself. During the process of MIG / MAG welding and / or recharging, the electric arc created / existing between the consumable electrode 10 and the part 30 is protected by a flow of protective gas against the atmosphere delivered by the torch 2 through the gas inlet 4, as shown in FIG. 2. Advantageously, the MIG / MAG electric arc is protected by a flow of gas containing mainly at least one inert compound selected from helium and argon, preferably at least 80% by volume, and optionally a minor chemical oxidizing compound selected from oxygen (02) and carbon dioxide (CO2). The gas composition in order to create this gaseous shielding flux of the MIG / MAG electric arc is selected according to the constituent material of the part 30. In particular, in the context of a method according to the invention, for the welding and / or the refilling of a piece made of carbon steel, of the SG235 type, the MIG / MAG electric arc is preferably protected by a flow of gas containing approximately 82% of argon and 18% of CO2 (in volume in both cases), corresponding to the gaseous mixture ARCAL FORCE protection marketed by the company AIR LIQUIDE. And, still in the context of the process according to the invention, the welding and / or the reloading of a piece made of 304L stainless steel, the MIG / MAG electric arc is preferably protected by a gas flow. containing approximately 98% of argon and 2% of CO2 (in volume in both cases), corresponding to the ARCAL CHROME gaseous protection mixture marketed by AIR LIQUIDE. Figure 3 shows, in turn, a welding operation of at least one part 30 with another part (not shown in Figure 3), ie a reloading operation of a part 30, according to the present invention. In FIG. 3, in view of generating the relative displacement between said system 1 and the part 30 during the welding and / or reloading operation, the system 1 is rotated around the longitudinal axis of the part 30. , in the direction of rotation of the hands of a watch, in order to place the supply of additional wire 20 at the front of the torch 3. If it is desired to leave the system 1 in a fixed position, the part 30 is rotated anti-clockwise, always to place the additional wire feed 20 at the front of the torch 30. If it is desired to place the second feed of additional wire 20 in the rear position of the torch 2 during the welding and / or reloading operation, the different directions of movement of the torch 2 or the part 30 will be reversed. In the case where the system 1 comprises the second and third additional wire feeds 20, 40, the direction of movement of the torch is not essential because the system 10 has a symmetrical configuration along a plane perpendicular to the surface of the piece and the direction of movement of said system 1 and passing through the longitudinal axis of the consumable electrode 10.

In order to demonstrate that the deposition rate in a constant energy welding and / or reloading process is greatly improved, using a system 1 and a method according to the present invention, tests have been carried out and compared with configurations. of a system not covered by the present invention. These comparative tests were carried out on carbon steel parts of the SG235 type. The welding parameters were as follows: the MIG / MAG shielding gas contained 82% of argon and 18% of CO2 (by volume), corresponding to the ARCAL FORCE mixture marketed by the company AIR LIQUIDE, the direction of the feed of the consumable electrode 10 is perpendicular to the surface 30a of the workpiece, - the diameter of the consumable electrode 10 was 1 mm, the diameter dfl of the second and only additional wire 20 was 1.6 mm, the distance dt between the end of the first feed of the consumable electrode 10 was 15 or 18 mm, the welding speed Vs was set at 950 mm / min, the MIG / MAG welding torch 2 was fed with a reference current of 290 A and a set voltage of 30 V, the feed speed Ve of the consumable electrode 10 was 12.5 m / min, and the unwinding speed Vf of the additional wire 20 was 4 or 5 m / min. Various configurations, such as those shown in FIG. 4, relating to the positioning and the angular orientation of the second supply of additional wire 20, have been tested, in order to demonstrate the benefit of the invention when the position of concomitance between consumable electrode 10 and additional wire 20 to the surface 30a of the workpiece 30 and the orientation of the second feed of additional wire 20 at an angle α, i.e. 30 to 50 degrees, relative between the direction of supply of the consumable electrode 10 and the additional wire 20 are selected from the range defined by the invention, see claims 1 and 13. Under these optimal conditions, the rate of deposition is increased by 30% compared to a MIG / MAG welding configuration without addition of additional wire 20. And the weld seams obtained in this optimum configuration according to the invention have no defect and offer good mechanical characteristics. All the tests carried out are reported in Table 1 below, the tests marked with an asterisk * being covered by the present invention. Table 1 Concomitant test of Vf 1 * 40 0 15 4 2 40 5 15 4 3 60 0 18 4 4 * 60 5 15 4 5 * 60 0 15 4 When the positioning of the second additional wire feed 20 and its angular orientation do not fulfill the defined conditions of the invention, the additional wire 20 will strike the sheet (tests 2 and 4), thus resulting in a lower deposition rate and risk of presence of defects in the weld bead, due to the striking of the additional wire 20 on the surface 30a of the part 30. When the distance between the guide 3, or contact tube 3, of the torch 2 is outside the usual values of an optimal MIG / MAG welding, there is occurrence of instabilities of the electric arc 40, causing material projections out of the area of the electric arc 40, from the interaction of the "cold" additional wire 20 with the transfer of material from the consumable electrode 10 MIG / MAG. The results of these tests confirm the interest of the system and the method of welding and / or reloading according to the invention to optimally increase the melt deposition rate and this constant energy, without the cords of deposited material. have no defects. In addition, it is possible to obtain this optimal melt deposition rate for materials constituting different parts.

Claims (15)

REVENDICATIONS1. System (1) for welding and / or reloading a workpiece (30) with a consumable electrode (10), comprising a welding torch (2) of the MIG / MAG type, a first feed of wire (3) for the consumable electrode (10) in the torch, and a second feed of wire to bring an additional wire (20) to a place of welding and / or reloading, characterized in that this second feed of wire is arranged vis-à-vis the welding torch (2) so as to establish an angle (a) between the additional wire (20) and the consumable electrode (10) between 30 and 70 degrees, and, in use, a point of impact of the consumable electrode (10) and the additional wire (20) concomitant on the surface (30a) of the workpiece (30). 2. System (1) according to claim 1, characterized in that the angle (a) between the consumable electrode (10) and the additional wire (20) is between 30 and 50 degrees, preferably the angle (a) is set at 50 degrees. 3. System (1) according to one of the preceding claims, characterized in that the system comprises the additional wire (20), and in that this second supply of additional wire (20) is independent of the torch (2) and / or this second supply of additional wire (20) and / or the additional wire (20) is independent (e) of a generator (4) of electrical power for welding. 4. System (1) according to one of the preceding claims, characterized in that the system (1) further comprises a member for adjusting the position and / or the angular orientation (a) of the second feed wire additional (20) with respect to the consumable electrode (10) and / or the torch (2). 5. System (1) according to claim 4, characterized in that the adjusting member connects the second supply of additional wire (20) to the torch (2). 6. System (1) according to one of the preceding claims, characterized in that, in use, the second supply of additional wire (20) is positioned relative to the direction (100) of welding and / or reloading, at the front or rear of an electric arc (40) created between the consumable electrode (10) and the surface (30a) of the workpiece (30). 7. System (1) according to one of the preceding claims, characterized in that the system (1) comprises a third supply of additional wire. 8. System (1) according to claim 7, characterized in that the third supply of additional wire is located opposite the second supply of additional wire (20) vis-à-vis the longitudinal axis of the consumable electrode (10). 9. System (1) according to one of the preceding claims, characterized in that the accuracy of said concomitance between the additional wire (20), the consumable electrode (10) and the surface (30a) of the workpiece (30) in the set of planes perpendicular to the surface (30a) of the workpiece (30) is preferably obtained by the accuracy inherent in the adjusting member included in the system (1), less than 1 mm, preferably smaller than at 0.5 mm, and more preferably still, less than 0.25 mm. 10. Installation for welding and / or reloading a part (30) characterized in that this installation comprises a system (1) for welding and / or reloading according to one of the preceding claims. 11. A method for MIG / MAG welding and / or recharging of a workpiece (30) with a consumable electrode (10) comprising the following steps: positioning a welding torch (2) with a first supply (3) of wire for the consumable electrode (10) and a second supply of additional wire (20) to the welding and / or charging location, - establishing an electric arc (40) between the consumable electrode (10) and the surface (30a) of the workpiece (30), characterized by the following step: - arranging the second feed of wire so as to establish an angle (a) between the additional wire (20) and the consumable electrode (10) between 30 and 70 degrees, and a point of impact of the consumable electrode (10) and the additional wire (20) concomitant on the surface (30a) of the workpiece (30). 12. The method of claim 11, characterized in that the step of arranging the second additional wire feed (20) is performed before the step of positioning the torch (2) and the second supply of additional wire (20). 13. A method according to one of claims 11 or 12, characterized in that the transfer rate of the material of the consumable electrode (10) has a sufficient energy level to ensure a transfer of drops in free flight, and preferably a transfer of drops in spray mode or in pulsed mode. 14. A method according to one of claims 11 to 13, characterized in that the electric arc (40) existing between the consumable electrode (10) and the part (30) is protected by a flow of protective gas against the atmosphere delivered by the torch (2), through a gas inlet (4), preferably said gas stream contains at least one inert compound preferably selected from helium and argon, preferably at least 80 % by volume, and optionally a minor chemical oxidizing compound selected from oxygen (02) and carbon dioxide (CO2). 15. Process according to claim 14, characterized in that the gas flow contains about 82% of argon and 18% of CO2, or the gas flow contains about 98% of argon and 2% of CO2. .