JP2018122310A - Arc-welding device, arc-welding method, and arc-welding magnetism controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arc-welding device capable of realizing high-quality welding at a high efficiency by suppressing arc interference and magnetic blow without being influenced by a construction condition such as welding attitude or interelectrode distance, an arc-welding method, and an arc-welding magnetism controller.SOLUTION: An arc welding device has a plurality of two or more electrodes consisting of one or both of non-consumable electrodes or consumable electrodes. This device comprises a pair of magnetic coils 65, 67 provided on both sides of an electrode 41 arranged in a most vicinity to the ground connection part of at least a work 19 of the plurality of electrodes, a coil excitation part 61 that excites the pair of magnetic coils 65, 67 to generate magnetic fluxes, and a control part which changes the external magnetic field around an arc with relative positions of the electrode 41 with the pair of magnetic coils 65, 67 and magnetic fluxes from the electrode 41 and the magnetic coils 65, 67.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an arc welding apparatus, an arc welding method, and a magnetic control apparatus for arc welding.

  For arc welding such as welding using a consumable electrode (Gas Metal Arc Welding: GMAW) or welding using a non-consumable electrode (Tungsten Inert Gas: TIG), a technique for improving efficiency by using a plurality of electrodes is known. ing. However, in the welding with a plurality of electrodes, arc interference occurs when the distance between the electrodes is short. On the other hand, when the distance between the electrodes is increased, magnetic blowing is likely to occur. For this reason, welding with a plurality of electrodes has a problem that welding quality becomes unstable due to poor penetration due to arc instability, poor bead appearance, or the like. In addition, these arc instabilities are also affected by the welding posture, and, for example, there has been a problem that bead sag is promoted in vertical or horizontal welding.

  In order to solve such disadvantages, for example, techniques of Patent Documents 1 and 2 are known. In the arc welding method using two non-consumable electrodes in Patent Document 1, arcs are alternately generated from two non-consumable electrodes using two opposing non-consumable electrodes as a cathode, and one molten pool (hereinafter referred to as 1 And the welding is performed while feeding the additive to the molten pool. In Patent Document 1, this arm welding method describes that even if one pool is formed by two non-consumable electrodes, the arcs of both electrodes do not interfere with each other, so that the molten pool is wide and stable. Moreover, since the bead width and the spread of the molten pool can be adjusted according to the distance between both electrodes, it is described that the fusion failure that easily occurs during the lamination welding is eliminated.

  Moreover, in the multi-electrode welding method of Patent Document 2, in the horizontal multi-electrode welding, a torch in the width direction of the groove is formed with respect to the horizontal groove formed in the base material among the walls forming the groove. A plurality of electrodes of the main body are arranged. That is, the method of Patent Document 2 is a multi-electrode welding method in which an arc is generated between a base material and a plurality of electrodes to perform welding, and one of the walls forming a groove is the other wall. When positioned on the lower side, the postures of the plurality of electrodes are controlled so that the arc is deflected toward the lower wall. This promotes the melting of the lower side of the groove, avoids the lower side from becoming insufficiently melted, prevents the overlap part from occurring, and suppresses the upper molten metal from dripping, And Patent Document 2.

JP-A-5-131273 JP 2002-1537 A

  However, Patent Document 1 assumes one pool of welding. The method of mutually generating arcs using the welding current as a pulse current is effective only for arc interference that occurs when the distance between the electrodes is short. That is, in order to disperse the heat input, as shown in FIG. 12, when the distance between the electrodes 501 and 503 is increased to form two pools, it is inevitable to be affected by magnetic blowing. In the case of a current in the same direction (for example, 150 A), magnetic force lines B1 and B2 in the same direction are generated in the electrode 501 and the electrode 503. In particular, when the ground connection part can be installed only at one place (position P in the figure) due to the restriction of the ground connection part of the ground line 507 of the work 505, the total current flowing between the electrode 503 and the ground line 507 Is larger than between the electrode 501 and the electrode 503 (I1 <I2). Therefore, a magnetic field larger than that of other parts is generated at the electrode 503 near the position P of the ground connection portion with the ground line 507, and magnetic blow (Mb1 <Mb2) becomes significant. Further, the cited document 1 does not describe anything about the welding posture such as the horizontal direction and the vertical direction.

  Patent Document 2 suppresses overlap and undercut that tend to occur in a horizontal welding posture in a plurality of electrodes. However, the distance between the electrodes is short and one pool is assumed. Not considered. Also, no particular consideration is given to arc interference and magnetic blow problems. Furthermore, even if Patent Document 1 and Patent Document 2 are combined, it cannot be solved with respect to magnetic blowing which is a problem in welding of two or more pools.

  The present invention has been made in view of the above situation, and its purpose is not affected by the welding conditions and the construction conditions such as the distance between the electrodes, and by suppressing arc interference and magnetic blowing, high-quality welding is highly efficient. It is an object to provide an arc welding apparatus, an arc welding method, and a magnetic control apparatus for arc welding that can be realized by the above.

According to one aspect of the present invention, two or more electrodes including one or both of a non-consumable electrode and a consumable electrode are arranged along a welding direction, and a welding current is applied between the plurality of electrodes and the workpiece to arc. An arc welding apparatus for generating
A magnetic flux is generated by exciting a pair of magnetic coils provided on both sides of the electrode disposed at least on both sides of the electrode disposed at least near the ground connection portion of the workpiece. And a control unit that changes an external magnetic field around the arc in accordance with a relative position between the electrode and the pair of magnetic coils and a magnetic flux from the electrode and the pair of magnetic coils. It can be an arc welding apparatus.

  In one embodiment of the present invention, two or more electrodes including one or both of non-consumable electrodes and consumable electrodes are arranged along the welding direction, and a welding current is applied between the plurality of electrodes and the workpiece. An arc welding method for generating an arc, comprising: a pair of magnetic coils provided on both sides of the plurality of electrodes, the electrodes arranged closest to the ground connection portion of the workpiece, on both sides of the electrodes. An arc welding method may be employed in which magnetic flux is generated by excitation, and an external magnetic field around the arc is changed in accordance with the relative position between the electrode and the pair of magnetic coils, and the magnetic flux from the magnetic coils.

  Another aspect of the present invention is a magnetic control device for arc welding that controls the directivity of an arc generated in an electrode composed of a non-consumable electrode or a consumable electrode, and each of the lead wires is connected to each tip of a U-shaped iron core. A coil having a pair of winding portions wound around the coil, and a coil movement in which the magnetic coil is disposed with the electrode sandwiched between the pair of winding portions and is movably supported along the welding direction. The arc according to a mechanism, a relative position between the coil exciting portion that excites the magnetic coil to generate a magnetic flux, the electrode and the pair of winding portions, and a magnetic flux from the electrode and the pair of magnetic coils. It can be set as the magnetic control apparatus for arc welding provided with the control part which changes the surrounding external magnetic field.

  According to the arc welding apparatus and the arc welding method of the present invention, arc interference and magnetic blowing can be suppressed without being affected by construction conditions such as a welding posture and a distance between electrodes, and high-quality welding can be realized with high efficiency.

  Moreover, according to the magnetic control apparatus for arc welding of this invention, the external magnetic field which can suppress an arc interference and a magnetic blowing can be generated, without being influenced by construction conditions, such as a welding attitude | position and a distance between electrodes.

It is an external view of the arc welding apparatus of the 1st example of composition. It is a principal part perspective view of the arc welding apparatus shown in FIG. FIG. 3 is a partially enlarged view of the arc welding apparatus shown in FIG. 2. It is a typical top view of the 1st coil unit, the 2nd coil unit, the 1st welding torch, and the 2nd welding torch. It is typical explanatory drawing which shows the positional relationship of the electrode of a welding torch and a coil unit. It is a control block diagram of an arc welding system. It is operation | movement explanatory drawing showing the position and electric current direction of an electrode and a magnetic coil in the case of applying the electromagnetic force which makes an arc go to the welding direction upstream. It is operation | movement explanatory drawing showing the position and electric current direction of an electrode and a magnetic coil in the case of applying the electromagnetic force which directs an arc toward a welding direction downstream. It is operation | movement explanatory drawing showing the position and electric current direction of an electrode and a magnetic coil in the case of applying the electromagnetic force which makes an arc direct to one side orthogonal to a welding direction. It is operation | movement explanatory drawing showing the position and electric current direction of an electrode and a magnetic coil in the case of applying the electromagnetic force which directs an arc to the other side orthogonal to a welding direction. It is a principal part block diagram of the arc welding apparatus of the 2nd structural example. It is explanatory drawing which shows the generation | occurrence | production factor of the magnetic blow in the conventional arc welding method by 2 pools.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below.
If the arc welding apparatus of this invention is the structure which performs arc welding, a welding system will not be specifically limited. For example, it can also be suitably used for gas shielded non-consumable electrode arc welding methods such as TIG welding and gas shield consumable electrode arc welding methods such as MIG welding and carbon dioxide arc welding.

  Here, as an arc welding apparatus, a TIG welding apparatus that performs welding while moving upward in vertical welding will be described as an example. However, the present invention is not limited to this, and can be applied to any welding posture. It can also be applied to welding in the direction and downward.

[First configuration example]
FIG. 1 is an external view of an arc welding apparatus according to a first configuration example. In this specification, the Z-axis direction is the welding direction, the Y-axis direction is the normal direction of the weld surface, the X-axis direction is the direction perpendicular to the weld direction and the weld surface normal line, and each direction is a figure. Shown in the direction of the arrow 1.

  The arc welding apparatus 100 is a main apparatus of an arc welding system 200 (see FIG. 6) described later. The work 13 has a groove portion 15, and a rail 11 and a carriage 17 that can move along the rail 11 are arranged on the front side of the work 13. An arc welding apparatus 100 is mounted on the carriage 17 and the groove portion 15 is welded. The arc welding apparatus 100 having this configuration is configured such that vertical welding can be performed along the rail 11 from the lower side in the vertical direction toward the upper side. In addition, the arc welding apparatus 100 is connected to various power sources, gas supply units, cooling water supply units, and the like, which will be described later.

FIG. 2 is a perspective view of a main part of the arc welding apparatus 100 shown in FIG. Note that FIG. 2 shows the arc welding apparatus 100 shown in FIG. 1 in a state where the rail 11 is horizontally arranged so that the rail 11 faces downward.
The carriage 17 of the arc welding apparatus 100 includes a base 21 attached in parallel to the rails 11 and a motor 29 for moving the base. The base 21 is provided with a first coil unit 57, a first torch unit 35, a second torch unit 37, and a second coil unit 59 from the upstream side in the welding direction (left side in FIG. 2). The first torch unit 35 and the second torch unit 37 are each provided with a slide portion (not shown) that is movable on the base 21. The base 21 is provided with a wire reel 23 for supplying filler wires, a wire feeding head 25, a gas suction unit 27, a motor 29, an operation unit 31, and the like, and can be moved along the rail 11 by driving the motor 29. Configured.

FIG. 3 is a partially enlarged view of the arc welding apparatus shown in FIG.
The first torch unit 35 includes a biaxial slider 47 and a first welding torch 39 attached to the biaxial slider 47. The first welding torch 39 incorporates an arc welding electrode (not shown). Similarly, the second torch unit 37 includes a biaxial slider 48 and a second welding torch 43 attached to the biaxial slider 48. The second welding torch 43 also includes an arc welding electrode (not shown).

  The first welding torch 39 and the second welding torch 43 are movable independently by the biaxial sliders 47 and 48, respectively. The biaxial sliders 47 and 48 slide the first welding torch 39 and the second welding torch 43 in the X-axis direction that is the width direction of the groove of the workpiece 19, that is, the lateral slide portion 51 that oscillates, and the thickness of the workpiece 19. And a vertical slide portion 53 for sliding the welding torch in the Y-axis direction which is the vertical direction.

  The horizontal slide portion 51 and the vertical slide portion 53 have a power transmission mechanism that transmits the power of a motor (not shown), and automatically slide the electrodes of each welding torch in the X-axis direction and the Y-axis direction, respectively. It is also possible to perform the weaving operation of each welding torch during welding.

  The first coil unit 57 includes a pair of magnetic coils 65 and 67 so as to sandwich the first welding torch 39 in the X-axis direction. The magnetic coils 65 and 67 include an iron core 69 serving as a core and a winding portion 68 around which a conducting wire is wound, and generate an external magnetic field that deflects an arc. The shape of the iron core 69 is not particularly limited, but may be, for example, a horseshoe type (U-shaped). In that case, the winding part 68 should just be provided in a pair of U-shaped front-end | tip part, respectively.

  The second coil unit 59 has the same configuration as the first coil unit 57 and includes a pair of magnetic coils 65 and 67 so as to sandwich the second welding torch 43 in the X-axis direction. The magnetic coils 65 and 67 include a horseshoe (U-shaped) iron core 69 serving as a core and a winding part 68 around which a conducting wire is wound.

  The first coil unit 57 and the second coil unit 59 are disposed so as to be inclined to the outside between the torches from the welding torches 39 and 43 disposed in parallel to the Y-axis direction. Accordingly, each of the magnetic coils 65 and 67 is arranged on both sides of the welding torches 39 and 43 with the tip of the iron core 69 inserted in an oblique direction.

  The first coil unit 57 is supported by the coil moving mechanism 71. One end of the coil moving mechanism 71 is fixed to the base 21 and supports the first coil unit 57. The coil moving mechanism 71 includes sliders in the Z-axis direction, the X-axis direction, and the Y-axis direction, and supports the first coil unit 57 so that the relative position with the welding torch 39 can be changed.

  The second coil unit 59 is supported by a coil moving mechanism 72 having the same configuration as the coil moving mechanism 71 so that the relative position with the welding torch 43 can be changed.

  The coil moving mechanisms 71 and 72 may be configured to move the first coil unit 57 and the second coil unit 59 by motor driving, or may be configured to move manually. Furthermore, the coil moving mechanisms 71 and 72 may be mechanisms that simply fix the first coil unit 57 and the second coil unit 59 to desired positions.

A gas suction part 27 is disposed between the first welding torch 39 and the second welding torch 43. The gas suction unit 27 is disposed at an intermediate position between the first welding torch 39 and the second welding torch 43 and sucks ambient gas including spatter and fumes generated from the second welding torch 43 and excess shielding gas. The suction amount is preferably in the range of 0.1 to 2.0 (m ³ / min).

  Instead of the gas suction part 27, a shielding member such as a plate member that shields the surrounding space for each welding torch may be provided between the welding torches. Further, both the gas suction part 27 and the shielding member may be provided.

  The biaxial sliders 47 and 48 described above change the welding position by the first welding torch 39 and the second welding torch 43 and the welding torch interval according to the shape of the work 19. The coil moving mechanisms 71 and 72 follow the movement of the welding torches 39 and 43 and change the relative positions of the welding torches 39 and 43 and the magnetic coils 65 and 67.

FIG. 4 is a schematic top view of the first coil unit 57, the second coil unit 59, the first welding torch 39, and the second welding torch 43.
The first coil unit 57 and the second coil unit 59 are arranged such that the open end side of the horseshoe-shaped (U-shaped) iron core 69 faces each other and the axial direction of the winding portion 68 is parallel to the Z-axis direction. The inter-electrode distance Wt between the electrode 41 included in the first welding torch 39 and the electrode 41 included in the second welding torch 43 is preferably 50 mm to 400 mm. When the interelectrode distance Wt is 50 mm or more, the amount of heat input to the workpiece can be suppressed, and when it is 400 mm or less, the bead appearance can be improved.

  FIG. 5 is a schematic explanatory view showing the positional relationship between the electrode of the welding torch and the coil unit. In the illustrated example, only the first coil unit 57 and the first welding torch 39 are shown, but the same applies to the second coil unit 59 and the second welding torch 43. FIG. 5 is a plan view seen from a direction perpendicular to the coil axis Lx of the magnetic coils 65 and 67, and the electrode 41 of the first welding torch 39 in the drawing indicates the electrode tip position.

  The magnetic coils 65 and 67 are arranged such that the coil axis lines Lx are parallel with the electrode 41 as the center. The The electrode 41 is disposed so as to be movable relative to the magnetic coils 65 and 67 in the Z-axis direction that is the welding direction. The relatively movable distance Ls is preferably within 1.5 times the axial total length Lc of the winding portion 68 with the center point Oc in the axial total length Lc of the winding portion 68 of the magnetic coils 65 and 67 as the center.

  That is, the relative positions of the electrode 41 and the magnetic coils 65 and 67 can be changed between the distances Ls by the horizontal slide portion 51 of the biaxial sliders 47 and 48 and the coil moving mechanisms 71 and 73 described above. ing.

  The magnetic coils 65 and 67 are ones in which the number of turns of the conducting wire in the winding portion 68 is 1600 and the inter-axis distance Wc between the coil axis lines Lx of the respective magnetic coils 65 and 67 is in the range of 80 mm to 200 mm. it can. A shortage of magnetic field does not occur when the number of windings of the conducting wire is 800 times or more, and an enlargement of the outer diameter of the magnetic coil does not occur when it is 1600 times or less. Further, when the distance between the pair of winding portions is 80 mm or more, interference between the magnetic coil and the electrode can be suppressed, and when it is 200 mm or less, a shortage of the magnetic field is less likely to occur. Note that the above-described inter-axis distance Wc is appropriately increased or decreased according to the shape of the component. Also, the number of turns of the conducting wire described above is appropriately increased or decreased according to the desired magnetic flux density applied to the arc point.

  The relative position between the electrode 41 and the magnetic coils 65 and 67 is an adjustment parameter for deflecting an arc generated from the electrode 41, as will be described later.

FIG. 6 is a control block diagram of the arc welding system 200.
The arc welding system 200 includes a control unit 73 provided separately from the arc welding apparatus 100 mounted on the carriage 17.

  The control unit 73 controls the operation of each unit constituting the arc welding apparatus 100. For example, the control unit 73 moves the carriage 17 by the motor 29, slides the first welding torch 39 by the two-axis sliders 47 and 48, slides the second welding torch 43, the first coil unit 57 by the coil moving mechanisms 71 and 72, Operations such as sliding of the two-coil unit 59 and supply of filler wire by the wire feeding head 25 are controlled.

  The controller 73 is connected to a coil exciter 61 that supplies power to the magnetic coils 65 and 67 (see FIG. 3) of the first coil unit 57 and the second coil unit 59. The control unit 73 outputs the coil excitation power input from the coil excitation unit 61 to the first coil unit 57 and the second coil unit 59, respectively. The control unit 73 has a function of controlling the amount of power supplied to the magnetic coils 65 and 67 and reversing the direction of the current. As described above, the control unit 73 reverses the excitation polarity or changes the coil position by the coil moving mechanisms 71 and 72, so that the external magnetic field around the arc of the first welding torch 39 and the second welding torch 43. It has a function to change. Further, the reversal of the excitation polarity and the movement of the coil position may be performed by the control unit 73, but may be performed by a controller or the like provided separately from the control unit 73.

  The control unit 73 is connected to the operation unit 31 via the relay unit 33 mounted on the carriage 17. The operation unit 31 includes an operation button, a display unit, and the like (not shown) for setting welding conditions, control conditions for the coil unit, and the like. With each operation button, an operation for changing the setting of the welding conditions determined in the welding operation from the user, an operation for starting the welding operation, and the like are accepted. The operation unit 31 has a connector with an external memory, and stores the welding conditions transferred from the control unit 73 during the welding operation in the external memory connected to the connector. The external memory is a storage medium that is detachably attached to the operation unit 31. For example, a flash memory is used from the viewpoint of general purpose, large capacity, and small size, but is not limited thereto.

  The display unit of the operation unit 31 includes a liquid crystal monitor or the like, and displays the contents of welding conditions, error information, and the like. Here, the error information is information relating to an error that has occurred before or during the welding operation. The error information includes, for example, information related to errors such as arc interruption, arc stop, electrode short circuit, servo abnormality, and power supply abnormality.

  Further, the arc welding system 200 applies a welding voltage to each electrode of the first welding torch 39 and the second welding torch 43 to generate an arc, and the TIG welding power sources 75A and 75B and the wire feeding head 25 respectively. MC power supplies 77A and 77B for supplying power to the filler wire of the electrode, a cooling water circulation driving unit 79 for circulating cooling water to each welding torch, and a shield gas supply driving unit 91 for supplying shielding gas to each welding torch. These are also connected to the control unit 73 and driven and controlled.

  The TIG welding power sources 75A and 75B apply a welding voltage between the electrodes of the first welding torch 39 and the second welding torch 43 and the workpiece. Further, the MC power supplies 77A and 77B supply a known arc adjusting voltage through a filler wire. Each ground line E of the TIG welding power sources 75A and 75B and the MC power sources 77A and 77B is connected to the workpiece through the ground connection portion of the workpiece.

  The shield gas supply drive unit 91 is connected to an Ar gas cylinder 95 provided with a pressure controller 93 through a gas hose 97, and argon gas supplied from the Ar gas cylinder 95 is connected to the first welding torch 39 and the first gas through the gas hose 99. 2 Supply to welding torch 43.

  The cooling water circulation drive unit 79 circulates the cooling water through the first welding torch 39 and the second welding torch 43. The cooling water circulation drive unit 79 cools the cooling water returned from these welding torches to a predetermined temperature by heat exchange, and then supplies the cooling water again to each welding torch for cooling.

  In the arc welding system 200, all the controls may be performed by the single control unit 73, but a separate control unit may be provided for each application. For example, a control unit that controls the power supplied from the TIG welding power sources 75A and 75B to the electrode and the workpiece, the power supplied to the filler wires from the MC power sources 77A and 77B, and the coil excitation unit 61 that supplies the coil unit A control unit or the like that controls the power to be generated may be provided separately from the control unit 73.

  In addition, during the welding operation, the control unit 73 stores the welding conditions in the internal memory of the control unit 73, and transfers the welding conditions stored in the internal memory to an external memory connected to the connector of the operation unit 31.

Next, the operation of the arc welding apparatus 100 having the above configuration will be described.
Hereinafter, a state in which an external magnetic field is generated by a magnetic coil and arc interference and magnetic blowing are suppressed will be described with reference to FIGS.
FIG. 7 is an operation explanatory diagram showing the positions and current directions of the electrodes and magnetic coils when an electromagnetic force is applied to direct the arc toward the upstream side in the welding direction. In addition, since the 1st coil unit 57 and the 2nd coil unit 59, and the 1st welding torch and the 2nd welding torch 43 are the same structures, respectively, the same effect | action is acquired in both.

  The magnetic flux density and the magnetic field lines vary depending on the relative position between the electrode 41 and the magnetic coils 65 and 67, the current applied to the magnetic coils 65 and 67, and the current direction. For example, in the case of DC current and negative electrode polarity (DCEN) conditions, the electrode 41 is disposed downstream of the magnetic coils 65 and 67 in the welding direction WD so that the upstream side of the magnetic coil 65 in the welding direction WD becomes the N pole. Is passed through the magnetic coil 67 (in the direction of arrow D1 in the figure), and current is passed through the magnetic coil 67 so that the downstream side in the welding direction WD becomes the N pole (in the direction of arrow D2 in the figure). Then, the direction of the magnetic force line LMF1 due to the magnetic coil 65, the magnetic force line LMF2 due to the magnetic coil 67, and the magnetic force line LMF3 due to the electrode 41 are aligned in the same direction downstream of the welding direction WD of the electrode 41, and the magnetic flux density increases. On the other hand, in other parts around the electrode 41, the directions of the magnetic lines of force from the magnetic coils 65 and 67 and the electrode 41 do not match, and the magnetic flux density becomes relatively low. As a result, the arc generated from the electrode 41 during welding is mainly affected by the combined magnetic field line LMF at a portion having a high magnetic flux density, and an electromagnetic force EMF directed upstream in the welding direction WD.

  The direction of the electromagnetic force EMF acting on the arc changes depending on the current direction of the electrode 41 and the magnetic coils 65 and 67 and the relative position between the electrode 41 and the magnetic coils 65 and 67. Therefore, in the arc welding apparatus of this configuration, the control unit 73 (see FIG. 6) controls the current direction of the electrode 41 and the magnetic coils 65 and 67 and the relative position of the electrode 41 and the magnetic coils 65 and 67. Thus, the arc can be deflected upstream in the welding direction with respect to the welding direction WD.

FIG. 8 is an operation explanatory view showing the positions and current directions of the electrodes and magnetic coils when an electromagnetic force is applied to direct the arc toward the downstream side in the welding direction.
When the electrode 41 is arranged on the upstream side in the welding direction WD of the magnetic coils 65 and 67 under the same conditions as the applied current in the case shown in FIG. 7, the magnetic field lines LMF1 from the magnetic coil 65 and the magnetic coil 67 The magnetic field lines LMF2 and LMF3 from the electrode 41 are aligned in the same direction on the upstream side in the welding direction of the electrode 41, and the magnetic flux density increases. On the other hand, in the region around the electrode 41, the directions of the magnetic lines of force from the magnetic coils 65 and 67 and the electrode 41 do not match, and the magnetic flux density is relatively low. As a result, the arc generated from the electrode 41 during welding is mainly affected by the combined magnetic field line LMF at a portion having a high magnetic flux density, and an electromagnetic force EMF directed downstream in the welding direction WD.

  As shown in FIGS. 7 and 8, the direction of the electromagnetic force acting on the arc generated from the electrode 41 is welded by changing the relative position of the electrode 41 and the magnetic coils 65 and 67 along the welding direction WD. It can be adjusted to either the upstream side or the downstream side of the direction WD. The strength of the electromagnetic force can be adjusted by increasing or decreasing the current applied to the magnetic coils 65 and 67.

FIG. 9 is an operation explanatory diagram showing the positions and current directions of the electrodes and magnetic coils when an electromagnetic force is applied to direct the arc to one side (right side in the figure) orthogonal to the welding direction.
As in the case of FIGS. 7 and 8, the electrode 41 is arranged in the center of the welding direction WD of the magnetic coils 65 and 67 under the conditions of direct current and electrode negative polarity (DCEN), and the welding direction is set to the magnetic coils 65 and 67. Currents are supplied so that the upstream side of the WD becomes the N pole (in the directions of arrows D1 and D2 in the figure). Then, the direction of the magnetic force line LMF2 due to the magnetic coil 67 and the direction of the magnetic force line LMF3 due to the electrode 41 are aligned in the same direction on one side (left side in the figure) orthogonal to the welding direction WD of the electrode 41, and the magnetic flux density increases. On the other hand, in other parts around the electrode 41, the directions of the magnetic lines of force from the magnetic coils 65 and 67 and the electrode 41 do not match, and the magnetic flux density becomes relatively low. As a result, the arc generated from the electrode 41 at the time of welding is affected by the combined magnetic field line LMF mainly at a portion having a high magnetic flux density, and the electromagnetic force EMF directed toward the other side (right side in the figure) perpendicular to the welding direction WD. Works.

FIG. 10 is an operation explanatory view showing the positions and current directions of the electrodes and magnetic coils when an electromagnetic force is applied to make the arc go to the other side (left side in the figure) perpendicular to the welding direction.
The case of FIG. 10 is the same as the case of FIG. 9 except that the polarities of the magnetic coils 65 and 67 are reversed from those in the case of FIG. In this case, the direction of the magnetic force line LMF1 due to the magnetic coil 65 and the direction of the magnetic force line LMF3 due to the electrode 41 are aligned in the same direction on the other side (right side in the figure) orthogonal to the welding direction WD of the electrode 41, and the magnetic flux density is increased. . On the other hand, in other parts around the electrode 41, the directions of the magnetic lines of force from the magnetic coils 65 and 67 and the electrode 41 do not match, and the magnetic flux density becomes relatively low. As a result, the magnetic force EMF directed toward one side (the left side in the figure) perpendicular to the welding direction WD acts on the arc generated from the electrode 41 during welding mainly by the combined magnetic field lines LMF of the portion having a high magnetic flux density. Works.

  As shown in FIGS. 9 and 10, the electrode 41 is arranged in the center of the welding direction WD of the magnetic coils 65 and 67, and the direction of the current is changed while making the polarity of the magnetic coils 65 and 67 the same with respect to the welding direction WD. By doing so, the direction of the electromagnetic force acting on the arc generated from the electrode 41 can be adjusted to either the one side or the other side perpendicular to the welding direction WD. The strength of the electromagnetic force can be adjusted by increasing or decreasing the current applied to the magnetic coils 65 and 67.

  In this way, the arc welding apparatus 100 can control the deflection direction of the arc in a total of four directions including the upstream direction, the downstream direction, and the two directions orthogonal to the welding direction with respect to the welding direction WD. When it occurs, the influence of magnetic blowing can be canceled by generating an electromagnetic force in the opposite direction to the direction of magnetic blowing.

  Here, the force applied to the arc varies depending on the magnetic flux density at the electrode position, and if it is less than 10 mT, the force acting on the arc is insufficient, and if it exceeds 90 mT, the force acting on the arc becomes excessive. Therefore, it is preferable that it is 10-90 mT as a range which can stabilize welding quality most. In the case of preventing magnetic blowing, the intensity of the magnetic blowing that becomes the largest depends on the sum of the currents flowing through the plurality of electrodes. Therefore, in the electrode closest to the ground connection part (in this configuration example, the electrode of the second welding torch 43), the range of the ratio of the total current and the magnetic flux density (total current / magnetic flux density) is 1.5 to 60.0. It is more preferable. By setting the ratio of the total current and the magnetic flux density to 60.0 or less, a shortage of the magnetic field does not occur, and by setting the ratio to 1.5 or more, enlargement of the outer diameter of the magnetic coil can be suppressed.

Next, an arc welding method using the arc welding apparatus 100 having the above configuration will be described.
The arc welding apparatus 100 is applicable to uses such as welding a side plate of an LNG tank. That is, the first welding torch 39 and the second welding torch 43 are arranged in the extending direction with respect to the groove 49 (see FIG. 3) of the workpiece extending along the vertical direction, and the workpiece 19 and the first welding are arranged. Welding is performed by generating an arc between the electrode of the torch 39 and the electrode of the second welding torch 43. The rail 11 is attached to the side plate along the groove 49, and the arc welding apparatus 100 has the carriage 17 self-propelled on the rail 11.

  In this configuration example, the arc welding apparatus 100 has a pair of non-consumable electrodes (electrodes 41) arranged one by one on the upstream side and the downstream side with respect to the welding direction by TIG welding. These electrodes are arranged at predetermined welding positions in the XYZ axial directions by the positioning operation of the biaxial sliders 47 and 48 by the control unit 73 shown in FIG. The arc welding apparatus 100 generates an external magnetic field by magnetic coils 65 and 67 disposed on both sides of at least the electrode closest to the ground connection portion of the work 19 among the plurality of electrodes.

  The arc welding apparatus 100 deflects the arc generated in each of the first welding torch 39 and the second welding torch 43 by an external magnetic field controlled by the control unit 73 and suppresses magnetic blowing. The magnetic blowing suppression operation is controlled based on various data such as a magnetic blowing suppression data table stored in advance. The magnetic blow suppression data table includes, for example, the magnetic blow amount (displacement amount) generated in the first welding torch 39 and the second welding torch 43 according to the welding current, and the respective coil units for correcting the magnetic blow displacement amount. The information such as the drive current is included. The magnetic blow suppression data table is stored in the internal memory of the control unit 73, for example. The arc welding apparatus 100 performs welding by storing the drive current of these coil units from the control unit 73 in the external memory of the operation unit 31 together with other welding conditions. Thereby, in this arc welding method, it corresponds to the welding current in each of the first welding torch 39 and the second welding torch 43, and the arc generation position is upstream and downstream with respect to the welding direction by the control unit 73, and welding. It is possible to perform welding in a state in which the direction is controlled in a total of four directions including two directions orthogonal to the direction, and magnetic blowing is suppressed.

  According to the arc welding apparatus 100 having the above-described configuration, the pair of magnetic coils 65 and 67 are arranged on both sides of the electrode closest to the ground connection portion of the work 19. These magnetic coils 65 and 67 sandwiching the electrodes are arranged such that the axes of the magnetic coils 65 and 67 are along the welding direction of the workpiece 19. The posture along the welding direction of the workpiece 19 refers to a posture in which the axes of the magnetic coils 65 and 67 with respect to the workpiece 19 are parallel or inclined with respect to the welding surface of the workpiece 19 other than vertical.

  Each electrode 41 of the first welding torch 39 and the second welding torch 43 becomes an electrode plus or an electrode minus, and generates a magnetic field around the electrode. On the other hand, a magnetic field is generated by the current flowing through the magnetic coils 65 and 67 sandwiching the electrode 41. The arc is deflected by the magnetic field around these electrodes and the magnetic field of the magnetic coils 65 and 67. The force for deflecting this arc (electromagnetic force) is strengthened by the combined magnetic field where the lines of magnetic force are aligned. The direction of the electromagnetic force varies depending on the current direction of the electrode 41 and the magnetic coils 65 and 67 and the relative position between the electrode 41 and the magnetic coils 65 and 67. Therefore, in the arc welding apparatus, it is possible to control the direction of the arc in a total of four directions including the welding direction by controlling the current direction and relative position of the electrode and coil unit by the control unit 73. Thereby, arc interference and magnetic blowing can be suppressed.

  Further, in the arc welding apparatus 100, the position of the electrode 41 is not separated from the tip of the magnetic coil between the pair of magnetic coils 65 and 67 by a distance exceeding 1.5 times the total length of the winding portion. Thereby, the electromagnetic force required to deflect the arc can be secured with low power.

  Further, the arc welding apparatus 100 has, for example, a configuration with two electrodes and only one ground wire, and when a current of 150 A flows through each electrode, the total current is 300 A. The larger the total current, the larger the magnetic blow, so that a higher magnetic flux density is required to suppress the magnetic blow. Therefore, the range of the ratio between the total current and the magnetic flux density is set to 1.5 to 60.0 as described above.

  Moreover, in the arc welding apparatus 100, the gas suction part 27 (or the shielding member) suppresses arc instability at the electrode (leading electrode) of the welding torch on the upstream side in the welding direction. That is, in the welding in the vertical upward direction, the shield gas in the electrode (following electrode) of the welding torch on the downstream side in the welding direction rises along the groove 49 and entrains the surrounding air. It is possible to suppress arc instability of the leading electrode that occurs due to disturbance. In addition, this gas suction part 27 (or shielding object) becomes remarkable in the effect of arc stabilization especially by vertical welding.

  Moreover, the arc welding apparatus 100 can arbitrarily change the relative position of the first coil unit 57 and the second coil unit 59 with respect to the electrodes of the welding torch by driving the coil moving mechanisms 71 and 72. By changing the relative position, the direction of the electromagnetic force acting on the arc can be reversed with respect to the welding direction. Further, the pair of magnetic coils 65 and 67 can be moved in the separation direction (X-axis direction), whereby the electrode can be easily positioned at the center in the separation direction.

  In the arc welding apparatus 100, the distance between the electrodes of the first welding torch 39 and the second welding torch 43 is set in a range of 50 to 400 mm. Thereby, heat input can be suppressed when the distance between electrodes is 50 mm or more, and a bead appearance becomes favorable when it is 400 mm or less.

  Moreover, the arc welding apparatus 100 can make the magnetic field by a filler wire act on an arc by changing the electric current and polarity which are applied to a filler wire by MC power supply 77A, 77B. For this reason, by using together with formation of the external magnetic field by the 1st coil unit 57 and the 2nd coil unit 59, the direction control of an arc can be assisted.

[Second configuration example]
Next, the arc welding apparatus of the second configuration example will be described.
FIG. 11 is a main part configuration diagram of the arc welding apparatus of the second configuration example.
The arc welding apparatus 300 of this configuration example includes a welding torch 109 having an electrode 107, a biaxial slider 111, a magnetic coil 65, a magnetic coil 67, and a camera 115. Further, the magnetic coils 65 and 67 are connected to the same coil excitation unit 61 as described above, and are driven by a command from the control unit 73.

  In addition to the biaxial slider 111 and the camera 115, the control unit 73 is connected to the coil moving mechanisms 71 and 72 (see FIG. 3) similar to the above, although not shown, and performs overall control of each unit.

  The camera 115 is attached, for example, in the vicinity of the welding torch so that an arc can be imaged. The camera 115 outputs the captured image data as output information. The control unit 73 stores the output information output from the camera 115 in an image memory provided in an internal memory or the like. Then, the stored image data of the output information is processed by a program stored in the internal memory, and an arc attitude, for example, an arc center position is obtained. The control unit 73 calculates the deflection amount of the magnetic blow from the obtained arc attitude, and drives the coil excitation unit 61 according to the deflection amount of the magnetic blow.

  As a result, the arc welding apparatus 300 controls the current applied to the magnetic coils 65 and 67, the current direction, and the coil moving mechanism in accordance with the magnetic blow generated in the arc, so that the arc deflection caused by the magnetic blow is normal. It can be returned to the state. As a result, it is possible to perform welding while sequentially suppressing magnetic blowing.

  Therefore, according to the arc welding apparatuses 100 and 300 of each configuration example described above, the arc interference and the magnetic blowing are suppressed without being affected by the construction conditions such as the welding posture and the distance between the electrodes, and high-quality welding is highly efficient. Can be realized.

  Next, an embodiment in which arc welding is performed with the above-described configurations 1 and 2 will be described. In addition, the welding conditions demonstrated here are examples, and this invention is not limited to the following welding conditions.

The arc welding conditions are more preferably in the following ranges.
Welding current: 80-300A
Arc voltage: 5-15V
Welding speed: 5-30 cm / min
Distance between electrodes: 50-400mm

  When arc welding was carried out under the above welding conditions, it was confirmed that in both structural examples 1 and 2, generation of arc interference and magnetic blowing was suppressed, and high-quality welding could be performed.

  As described above, the present invention is not limited to the above-described embodiments, and those skilled in the art can make changes and applications based on combinations of the configurations of the embodiments, descriptions in the specification, and well-known techniques. This is also the scope of the present invention, and is included in the scope for which protection is sought.

  For example, although the above-described pair of welding torches each have a coil unit disposed therein, a configuration in which the coil unit is disposed only on the side of the welding torch disposed closest to the ground connection portion of the workpiece may be employed.

  In addition, each of the above-described pair of welding torches is a non-consumable electrode, but it may be a consumable electrode, and either one may be a non-consumable electrode and the other may be a consumable electrode.

  Moreover, the above-described arc welding apparatus may have a configuration in which a welding torch side that generates an arc and a coil unit side that generates a magnetic field are separated. In that case, a general-use apparatus configuration can be obtained by adding an arc welding magnetic control device including a coil unit, a coil moving mechanism, a coil excitation unit, and a control unit to an arbitrary arc welding device.

As described above, the following items are disclosed in this specification.
(1) An arc in which two or more electrodes composed of one or both of non-consumable electrodes and consumable electrodes are arranged along the welding direction, and an arc is generated by applying a welding current between the plurality of electrodes and the workpiece. A welding device,
A pair of magnetic coils provided on both sides of the electrode, the electrode disposed closest to the ground connection portion of the workpiece,
A coil exciter that excites a pair of magnetic coils to generate magnetic flux;
A control unit that changes an external magnetic field around the arc in accordance with a relative position between the electrode and the pair of magnetic coils, and a magnetic flux from the electrode and the pair of magnetic coils;
An arc welding apparatus comprising:
According to this arc welding apparatus, the magnetic coils are arranged on both sides of the electrode closest to the workpiece ground line. The magnetic coil sandwiching the electrodes is arranged such that the axis of the iron core is along the welding direction of the workpiece. The electrode becomes an electrode plus or an electrode minus and generates a magnetic field in the electrode itself. On the other hand, a magnetic field is generated by a current flowing through the magnetic coil sandwiching the electrodes. The arc is deflected by the magnetic field of these electrodes themselves and the magnetic field of each magnetic coil. The electromagnetic force that deflects the arc becomes stronger when the direction of the lines of magnetic force from each part is aligned. The direction of the electromagnetic force varies depending on the current direction of the electrode and the magnetic coil and the relative position of the electrode and the magnetic coil. Therefore, in the arc welding apparatus, the influence of the magnetic blow of the arc can be canceled by controlling the direction of the current of the electrode and the magnetic coil and the relative position of the electrode and the magnetic coil.

(2) The arc welding according to (1), wherein the electrode is arranged within a range of 1.5 times or more of the total length of the winding portion around the midpoint of the total length of the winding portion of the magnetic coil with respect to the welding direction. apparatus.
According to this arc welding apparatus, the electromagnetic force necessary for deflecting the arc can be secured with low power between the pair of magnetic coils.

(3) The magnetic flux density generated in the electrode by the coil excitation unit is 10 to 90 mT,
The arc welding apparatus according to (1) or (2), wherein a ratio between a total current flowing through the ground connection portion and the magnetic flux density is 1.5 to 60.0.
According to this arc welding apparatus, for example, when there are two electrodes and one ground wire and 150 A flows through each electrode, the total current is 300 A. Since the magnetic blow occurs more strongly as the total current synthesized increases, a larger magnetic flux density is required to suppress the magnetic blow. Therefore, by setting the ratio of the total current and the magnetic flux density to 60.0 or less, a shortage of the magnetic field does not occur, and by setting the ratio to 1.5 or more, the enlargement of the magnetic coil outer diameter can be suppressed.

(4) The arc welding apparatus according to any one of (1) to (3), wherein a gas suction unit that sucks ambient gas is provided between the electrodes of the plurality of electrodes.
According to this arc welding apparatus, instability of the arc of the leading electrode among the plurality of electrodes is suppressed. For example, in welding in a vertical upward direction, the shielding gas of the trailing electrode rises along the groove, and this rising gas covers the surroundings of the leading electrode as a gas that encloses the surrounding air. The pole arc can be prevented from becoming unstable.

(5) The arc welding apparatus according to any one of (1) to (4), wherein a shielding member that shields a surrounding space for each electrode is provided between the electrodes of the plurality of electrodes.
According to this arc welding apparatus, instability of the arc of the leading electrode among the plurality of electrodes is suppressed. For example, in welding in the upward upward direction, the shield gas of the trailing electrode rises along the groove, and arc instability of the leading electrode generated by disturbing the shielding gas of the leading electrode can be suppressed.

(6) The arc welding device according to any one of (1) to (5), wherein the control unit moves the magnetic coil along the welding direction.
According to this arc welding apparatus, each magnetic coil can be moved by the coil moving mechanism. When the magnetic coil is moved in the welding direction, the direction of the electromagnetic force acting on the arc can be reversed.

(7) The arc welding device according to any one of (1) to (6), wherein the control unit reverses the excitation polarity of the magnetic coil.
According to this arc welding apparatus, by reversing the direction of the current supplied to the magnetic coil, the direction of the magnetic field lines of the external magnetic field around the arc is reversed, and the direction of the generated electromagnetic force can be easily reversed.

(8) The arc welding apparatus according to any one of (1) to (7), wherein the plurality of electrodes includes non-consumable electrodes including two electrodes, and a distance between the electrodes is 50 to 400 mm.
According to this arc welding apparatus, when the distance between the electrodes is 50 mm or more, arc interference and heat input concentration are eliminated, and when the distance is 400 mm or less, the bead appearance is improved.

(9) A wire feeding head that feeds at least one filler wire to the non-consumable electrode, a wire power source that applies current independently to the filler wire, and a current and polarity that are applied to the filler wire. An arc welding apparatus according to (8), further comprising: a wire current adjusting unit that changes at least one of them.
According to this arc welding apparatus, the magnetic field from an electrode can be made to interfere with an arc by changing the electric current and polarity of a filler wire by a wire current adjustment part. For this reason, the arc direction control can be assisted by using together with the formation of the external magnetic field by the magnetic coil.

(10) An arc in which two or more electrodes composed of one or both of non-consumable electrodes and consumable electrodes are arranged along the welding direction, and an arc is generated by applying a welding current between the plurality of electrodes and the workpiece. A welding method that generates a magnetic flux by exciting a pair of magnetic coils provided on both sides of an electrode arranged at least on the workpiece ground connection portion of the plurality of electrodes. An arc welding method in which an external magnetic field around the arc is changed according to a relative position between the electrode and the pair of magnetic coils and a magnetic flux from the magnetic coil.
According to this arc welding method, the magnetic coils are arranged on both sides of the electrode closest to the ground connection portion of the workpiece. The magnetic coil sandwiching the electrodes is arranged with the core axis along the workpiece. The electrode becomes an electrode plus or an electrode minus and generates a magnetic field in the electrode itself. On the other hand, a magnetic field is generated by a current flowing through the magnetic coil sandwiching the electrodes. The arc is deflected by the magnetic field of these electrodes themselves and the magnetic field of each magnetic coil. The electromagnetic force that deflects the arc becomes stronger when the lines of magnetic force are aligned. That is, the direction of the electromagnetic force varies depending on the current direction of the electrode and the magnetic coil and the relative position of the electrode and the magnetic coil. Therefore, in this arc welding method, it is possible to control the direction of the arc by controlling the current direction of the electrode and the magnetic coil and the relative position of the electrode and the magnetic coil. Thereby, arc interference and magnetic blowing can be suppressed.

(11) A magnetic control device for arc welding that controls the directivity of an arc generated in a non-consumable electrode or an electrode composed of a consumable electrode, wherein a pair of wires are wound around each tip of a U-shaped core. A magnetic coil having a winding portion, a coil moving mechanism that supports the magnetic coil so as to be movable along a welding direction, with the electrode sandwiched between a pair of the winding portions, and the magnetic coil The external magnetic field around the arc is changed in accordance with the relative positions of the coil excitation part that generates a magnetic flux by exciting the electrode and the pair of windings and the magnetic flux from the electrode and the pair of magnetic coils. And a magnetic control device for arc welding comprising:
According to this magnetic control apparatus for arc welding, a pair of magnetic coils are provided so as to sandwich the non-consumable electrode or the consumable electrode. Each magnetic coil has a conductive wire wound around an iron core in a coil shape. The iron core may be two independent rods or a horseshoe (U-shaped). A magnetic coil is arrange | positioned with the attitude | position in which the axis of an iron core follows a workpiece | work. The magnetic coil generates a magnetic field when a current flows. On the other hand, the electrode sandwiched between the magnetic coils also becomes an electrode plus or an electrode minus and generates a magnetic field in the electrode itself. The arc is deflected by the magnetic field of these electrodes themselves and the magnetic field of each magnetic coil. The electromagnetic force that deflects the arc becomes stronger when the lines of magnetic force are aligned. The direction of the electromagnetic force varies depending on the current direction of the electrode and the magnetic coil and the relative position of the electrode and the magnetic coil. Therefore, in the arc welding magnetic control device, it is possible to control the direction of the arc from front to back and from side to side by controlling the direction of the current of the electrode and the magnetic coil and the relative position of the electrode and the magnetic coil.

(12) The magnetic control device for arc welding according to (11), wherein the number of turns of the conductive wire of the winding portion is 800 to 1600 times, and a distance between the pair of winding portions is 80 to 200 mm.
According to this magnetic controller for arc welding, in the same iron core, the same conductor diameter, and the same voltage, the number of windings of the conductor is 800 times or more, and the magnetic field is not insufficient. Coil outer diameter is not enlarged. Further, when the distance between the pair of winding portions is 80 mm or more, interference between the magnetic coil and the electrode can be suppressed, and when it is 200 mm or less, a shortage of the magnetic field is less likely to occur. As a result, the direction of the arc can be controlled efficiently.

DESCRIPTION OF SYMBOLS 19 Work 25 Wire feed head 27 Gas suction part 39 1st welding torch 41 Electrode 43 2nd welding torch 47,48 2-axis slider 57 1st coil unit 59 2nd coil unit 61 Coil exciting part 65 Magnetic coil 67 Magnetic coil 68 Winding part 69 Iron core 71, 72 Coil moving mechanism 73 Control part 100, 300 Arc welding apparatus 200 Arc welding system

Claims (12)

An arc welding apparatus in which two or more electrodes composed of one or both of non-consumable electrodes and consumable electrodes are arranged along the welding direction, and an arc is generated by applying a welding current between the plurality of electrodes and the workpiece. There,
A pair of magnetic coils provided on both sides of the electrode, the electrode disposed closest to the ground connection portion of the workpiece,
A coil exciter that excites a pair of magnetic coils to generate magnetic flux;
A control unit that changes an external magnetic field around the arc in accordance with a relative position between the electrode and the pair of magnetic coils, and a magnetic flux from the electrode and the pair of magnetic coils;
An arc welding apparatus comprising:   2. The arc welding apparatus according to claim 1, wherein the electrode is disposed within a range of 1.5 times or more of the total length of the winding portion around the midpoint of the total length of the winding portion of the magnetic coil with respect to the welding direction. . The magnetic flux density generated in the electrode by the coil excitation unit is 10 to 90 mT,
The arc welding apparatus according to claim 1 or 2, wherein a ratio between a total current flowing through the ground connection portion and the magnetic flux density is 1.5 to 60.0.   The arc welding apparatus according to any one of claims 1 to 3, wherein a gas suction part that sucks ambient gas is provided between the electrodes of the plurality of electrodes.   The arc welding apparatus according to any one of claims 1 to 3, wherein a shielding member that shields a surrounding space of each electrode is provided between the electrodes of the plurality of electrodes.   The said control part is an arc welding apparatus as described in any one of Claims 1-5 which moves the said magnetic coil along the said welding direction.   The arc welding device according to any one of claims 1 to 6, wherein the control unit reverses the excitation polarity of the magnetic coil.   The arc welding apparatus according to any one of claims 1 to 7, wherein the plurality of electrodes includes non-consumable electrodes including two electrodes, and a distance between the electrodes is 50 to 400 mm. A wire feeding head for feeding at least one filler wire to the non-consumable electrode;
A wire power supply that applies current independently to the filler wire;
A wire current adjusting unit that changes at least one of the current and polarity applied to the filler wire;
An arc welding apparatus according to claim 8. An arc welding method in which two or more electrodes composed of one or both of non-consumable electrodes and consumable electrodes are arranged along the welding direction, and an arc is generated by applying a welding current between the plurality of electrodes and the workpiece. There,
Exciting a pair of magnetic coils provided on both sides of the electrode disposed closest to the ground connection part of the workpiece of the plurality of electrodes to generate a magnetic flux,
An arc welding method in which an external magnetic field around the arc is changed according to a relative position between the electrode and the pair of magnetic coils and a magnetic flux from the magnetic coil. A magnetic control device for arc welding that controls the directivity of an arc generated in an electrode composed of a non-consumable electrode or a consumable electrode,
A magnetic coil having a pair of winding portions each wound with a conducting wire at each tip of the U-shaped iron core;
A coil moving mechanism that disposes the magnetic coil between the pair of winding portions and supports the magnetic coil so as to be movable along the welding direction;
Depending on the relative position between the coil excitation part that excites the magnetic coil to generate magnetic flux, the electrode and the pair of winding parts, and the magnetic flux from the electrode and the pair of magnetic coils, the outside around the arc A controller that changes the magnetic field;
A magnetic control device for arc welding comprising: The number of turns of the conducting wire of the winding part is 800 to 1600 times,
The magnetic control device for arc welding according to claim 11, wherein a distance between the pair of winding portions is 80 to 200 mm.

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