JP2003145270A - Method for terminating consumable two-electrode arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems occurring in a conventional technique 2 of a high speed welding that the width of bead decreases, shortage of penetration, and a humping bead occur because the moving speed of a welding torch is too high to perform the welding only with a following wire after decreasing the current and the voltage which are applied to a foregoing wire at near the terminal position of welding. SOLUTION: In the method for terminating the consumable two-electrode arc welding, the electric current which is supplied to the foregoing wire 3 and the following wire 4 at a point near the terminal position P1 of welding is set smaller than a conventional welding current, the welding torch 14 is moved in the welding direction at a speed lower than a conventional welding speed, the feeding and the energizing of the foregoing wire 3 are interrupted at a terminating position of welding P2, the welding torch 14 is moved in the welding direction by a first crater processing distance D1 of the following wire at a speed slower than the conventional welding speed while the following wire 4 performs the first crater processing, the welding torch 14 is stopped and the following wire 4 performs a second crater processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method of terminating arc welding in which two consumable electrodes (hereinafter referred to as wires) are fed and welded in one torch in consumable electrode arc welding. .

[0002]

2. Description of the Related Art In the construction of various welded structures, thin plate high-speed welding or thick plate high-welding welding is performed to improve work efficiency.
As shown in FIG. 1, a two-electrode one-torch type consumable electrode arc welding method of feeding two wires from one torch is adopted. In the same drawing, electric power is supplied from a welding power source (not shown) between the leading tip 1 and the trailing tip 2 and the object 8 to be welded, and the leading wire tip 3a is fed from the leading tip 1 and the trailing tip 2 respectively. And trailing wire tip 4
Arcs 5 and 6 are generated from a. The nozzle 10 surrounds the leading tip 1 and the trailing tip 2 and supplies the shield gas 11 to the inside of the nozzle 10.

In FIG. 2, the molten metal in the molten pool 7 formed by the arc 5 generated from the leading wire 3 tries to flow backward due to the surface tension or the arc force of the arc of the leading wire 3. The arc force generated from the row wire 4 pushes the molten metal, which tends to flow backward, toward the arc 5 generated from the preceding wire 3,
The amount of molten metal at each welding position is made uniform.

FIG. 3 is a diagram showing a general configuration of the welding robot of the two-electrode one-torch type described above. In the figure, a welding torch 14 having a leading tip 1 and a trailing tip 2 is attached to the tip of a manipulator 21, and a leading wire welding power supply device 23 for feeding the leading tip 1 and a trailing wire for feeding the trailing tip 2 are supplied. Power source for wire welding 24
Supplies welding electric power between the leading tip 1 and the trailing tip 2 and the workpiece 8. Leading wire feeder 2
5 and the trailing wire feeding device 26 feeds the wires to the leading tip 1 and the trailing tip 2, respectively. The robot controller 27 controls the manipulator 21, the power supply device 23 for leading wire welding, and the power supply device 24 for trailing wire welding. It should be noted that when the welding direction is changed, the leading and trailing parts are replaced with each other. Therefore, the leading tip 1, leading wire 3, leading wire feeding device 25, leading wire welding power supply device 23, trailing tip 2, trailing wire 4, and trailing wire 4, The preceding and following explanations of the reference numerals of the row wire feeding device 26 and the trailing wire welding power source device 24 are replaced with each other.

[Prior Art 1] 2 conventionally proposed
A welding termination method using a welding robot of the electrode 1 torch method (hereinafter referred to as prior art 1) will be described with reference to FIGS. 4 and 5. To simplify the description, the leading wire 3
And the case where the trailing wire 4 is fed. FIG. 4 is a diagram for explaining a method of terminating the consumable electrode arc welding of the two-electrode one-torch method of the conventional technique 1, and FIG. 5 is a diagram of the two-electrode one-torch type consumable electrode arc welding of the conventional technique 1 following FIG. It is a figure explaining an end method.

FIG. 4 (A) shows a state in which the two-electrode one-torch type consumable electrode arc welding is being performed. In the figure, the nozzle 1
The leading wire 3 and the trailing wire 4 protrude from 0, and the leading wire 3 and the trailing wire 4 and the work piece 8 are welded from the leading wire welding power source device 23 and the trailing wire welding power source device 24 shown in FIG. Electric power is respectively supplied between them, arcs 5 and 6 are respectively generated from the leading wire tip 3a and the trailing wire tip 4a, and the welding bead 9 is formed.

Then, as shown in FIG. 4 (B), when the leading wire tip 3a reaches the welding end position P2, which is the end portion of the welding bead formed by the leading wire 3, the robot controller shown in FIG. 27 determines that the leading wire tip 3a has reached the welding end position P2, and outputs a crater processing command signal to the leading wire welding power supply device 23 and the trailing wire welding power supply device 24.

Here, the crater processing will be described. At the end of the weld bead, a so-called crater is formed in the molten pool immediately below the arc due to the arc force. Defects such as cracks and shrinkage holes are likely to occur in this crater. To prevent this, the operation of reducing or eliminating the crater is called crater processing. Generally, a method such as continuously or stepwise decreasing the welding current at the terminal end of the welding bead, or interrupting the welding current is used. The above-mentioned conventional technique 1
In the present invention, the crater process of is referred to as a second crater process.

After that, when the crater processing is completed,
The robot control device 27 shown in FIG. 3 inputs a welding end command signal to the power supply device 23 for leading wire welding and the power supply device 24 for trailing wire welding, and as shown in FIG.
Finish welding.

FIG. 5 is a view showing the external appearance of the welding bead end portion by the method of terminating the consumable electrode arc welding of the two-electrode one-torch method of the prior art 1. As shown in the figure, since both the leading wire 3 and the trailing wire 4 perform crater processing, two crater processing traces 15 and 16 are generated. Also,
A large molten pool mark is generated by the arc force of the leading wire and the trailing wire, and since this is a large depression 13, not only the appearance of the weld bead is poor, but also the weld joint strength is weakened, cracks, shrinkage holes, etc. Defects are likely to occur.

[Prior Art 2] In order to solve the above problems, Japanese Patent Laid-Open No. 2001-113373 "Tandem Arc Welding Control Method" (hereinafter referred to as Prior Art 2) has been proposed. FIG. 6 is a diagram showing an apparatus for performing tandem arc welding according to the related art 2. In the figure, a leading wire welding power source device 44 and a trailing wire welding power source device 4 are provided between the leading tip 41 and the trailing tip 42 and the workpiece 2.
5 supply electric power, respectively. Leading wire feeder 46
The trailing wire feeding device 47 supplies the leading wire 48 and the trailing wire 49 to the leading tip 41 and the trailing tip 42, respectively, to generate the arc 50 and the arc 51. The arc 50 and the arc 51 form a molten pool 52, and a weld bead 53 is formed behind the molten pool 52. The welding control device 54 controls the operation of the welding robot 55 and the power supply device 44 for leading wire welding and the power supply device 4 for trailing wire welding.
5 output control.

FIG. 7 is a time chart for explaining the control method at the end of welding according to the prior art 2. FIG. 7A shows the time t of the leading wire energizing current, and FIG. The time t of the wire applied voltage is shown, the time t of the moving speed of the leading tip 41 and the trailing tip 42 is shown in the same figure (C), and the time of the trailing wire conducting current is shown in the same figure (D). The time t is shown, and the same figure (E) shows the time t of the trailing wire applied voltage.

At time t1 shown in FIG. 7, when the leading tip 41 reaches the welding end position P2, the energizing current of the leading wire 48 is reduced from I1 to I2 as shown in FIG. As shown in FIG.
The applied voltage of 8 is reduced from E1 to E2. After that, after the waiting time Td1 has elapsed, the arc of the leading wire 48 is stopped to reduce the molten pool.

At time t2 in the figure, the trailing chip 42
When the welding end position P2 is reached, the movement of the leading tip 41 and the trailing tip 42 is stopped as shown in FIG. Then, as shown in FIG.
The current flowing through the wire is reduced from I3 to I4, and as shown in FIG.
To E4. After that, after the waiting time Td2 has elapsed, the arc of the trailing wire 49 is stopped.

The energizing currents I2 and I4 reduced before the arc is stopped are half of the welding currents I1 and I2 of welding until the welding torch reaches the welding end position (hereinafter referred to as normal welding). The degree is appropriate. Further, the applied voltages E2 and E4 reduced before the arc is stopped may be set to values suitable for the reduced energizing currents I2 and I4, respectively.

As described above, in the prior art 2, the current flowing to the leading wire 48 and the trailing wire 49 and the applied voltage are reduced at the end of welding, and stopped after a waiting time, thereby preventing the molten metal from scattering and melting. Not only the stable solidification of the pond can be achieved, but also a good welding end portion without unevenness, pits, cracks and other welding defects can be obtained, but it has the following problems.

[0017]

The first problem in the above-mentioned prior art 2 is that, as shown in FIG.
After reducing the current and voltage applied to No. 8, welding is performed only by the trailing wire 49. The welding speed at this time is a speed for performing high-speed welding, as shown in FIG. Therefore, since the moving speed of the leading tip 41 and the trailing tip 42 is too fast to perform welding only by the arc of the trailing wire 49 after reducing the current and voltage applied to the leading wire 48, the welding bead width May decrease, insufficient melting may occur, or a humping bead may occur, and the weld bead near the welding end position may not be uniform and have a beautiful appearance. Also, the welding speed is 2 [m
In high-speed welding in excess of 1 / min.], In order to obtain a uniform weld bead, the ratio of the average current flowing through the leading wire 48 and the average current flowing through the trailing wire 49 is about 2: 1. Therefore, if the current supplied to the leading wire 48 is reduced and stopped while maintaining the high speed welding speed, the ratio of the currents supplied to the leading wire 48 and the trailing wire 49 is not an appropriate ratio, and high speed welding is performed. A trailing wire 49
Arc force becomes excessive, the arc force blows away the molten pool, the weld beads become non-uniform, and welding defects occur. Further, in the case of high welding, the molten pool is largely dented by the arc force of the leading wire 3 and the trailing wire 4, and the dent extends to the rear of the following wire 4. Therefore, the conventional technique 2
Since the welding speed is constant, it is not possible to fill this recess with weld metal. These depressions solidify to form molten pool marks,
Defects such as cracks and shrinkage holes easily occur.

Further, the second problem in the conventional technique 2 is that, for example, as shown in FIG. 8, the shape of the object 8 to be welded is a box-shaped bottom plate having a wall in front of the welding end position P2 in the welding direction. When fillet welding is performed, the leading tip 41 reaches the welding end position P2, the leading tip 41 hits the wall, and the leading tip 41 and the trailing tip 42 cannot be moved in the welding direction. The control method of arc welding cannot be implemented. FIG. 8 shows an object to be welded 8
Is a box-like shape and is a diagram for explaining a case where fillet welding of the bottom plate is performed. Therefore, since the trailing tip 42 cannot reach the welding end position P2, as shown in FIG.
Since the welding is performed only by the welding bead 9a in the vicinity of the welding end position P2, the welding bead 9 becomes non-uniform, and a welding defect occurs. FIG. 9 is a diagram for explaining that the welding bead 9 at the welding end position P2 in the case of performing fillet welding of the bottom plate becomes non-uniform according to the related art 2 when the shape of the workpiece 8 is a box shape. .

[0019]

In order to solve the first and second problems of the prior art 2 at the same time, the invention according to claim 1 at the time of filing of the invention is based on the first embodiment shown in FIGS. 10 and 11. It is an invention in the case where the preceding wire 3 and the following wire 4 perform crater treatment, and in the consumable two-electrode arc welding ending method of feeding and welding two wires in one torch, at the welding end vicinity position P1. The welding torch 14 is moved at a speed slower than the normal welding speed in the welding direction by setting the current passing through the leading wire 3 and the trailing wire 4 to be lower than the normal welding current, and at the welding end position P2. This is a consumable two-electrode arc welding ending method in which the movement of 14 is stopped and the leading wire 3 and the trailing wire 4 perform crater processing.

In order to solve the first problem of the prior art 2, the invention according to claim 2 at the time of filing of the present invention has the advantage of FIG. 13 and FIG.
In the invention for the case where the trailing wire 4 of Embodiment 2 shown in FIG. 2 performs the first and second crater treatments, the method for terminating consumable two-electrode arc welding in which two wires are fed and welded in one torch. At the position P1 near the end of welding, the current to be passed through the leading wire 3 and the trailing wire 4 is made lower than the normal welding current, and the welding torch 14 is moved in the welding direction at a speed slower than the normal welding speed to perform welding. At the end position P2, the feeding and energization of the leading wire 3 are stopped and the welding torch 14 is moved in the welding direction at a speed slower than the normal welding speed by the trailing wire first crater processing distance D1. 4 is a consumable two-electrode arc welding ending method in which the first crater process is performed, the movement of the welding torch 14 is stopped, and the trailing wire 4 performs the second crater process.

In order to solve the first and second problems of the prior art 2 at the same time, the invention described in claim 3 at the time of application has the first wire 3 of the third embodiment shown in FIGS. 17 and 18 as the first wire. In the invention for performing the second crater treatment, in the consumable two-electrode arc welding ending method of feeding and welding two wires in one torch, the leading wire 3 and the trailing wire are provided at a position P1 near the end of welding. The current to be applied to the wire 4 is made lower than the normal welding current, the welding torch 14 is moved in the welding direction at a speed slower than the normal welding speed, and the trailing wire 4 is fed and energized at the welding end position P2. And the welding torch 14 is moved in the direction opposite to the normal welding direction at a speed slower than the normal welding speed and the preceding wire first crater processing distance D is reached.
This is a consumable two-electrode arc welding ending method in which the leading wire 3 performs the first crater treatment while moving only two, and then the movement of the welding torch 14 is stopped and the leading wire 3 performs the second crater treatment.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram best representing the features of the invention according to the present application. Since it is the same as FIG. 10 described later, the description will be described later with reference to FIG. 10. The embodiment of the invention is the consumable two-electrode arc welding ending method according to claim 1 at the time of filing, wherein the two consumable two-electrode arc welding ending method includes feeding and welding two wires in one torch. , At the position P1 near the end of welding, the current flowing through the leading wire 3 and the trailing wire 4 is made lower than the normal welding current, and the welding torch is moved in the welding direction at a speed slower than the normal welding speed,
At the welding end position P2, the movement of the welding torch is stopped and the leading wire 3 and the trailing wire 4 perform crater processing.
This is the method of ending electrode arc welding.

[0023]

[Embodiment 1] FIG. 10 shows a method for terminating consumable two-electrode arc welding according to the present invention, in which a leading wire 3 and a trailing wire 4 are fed, and the leading wire 3 and the trailing wire 4 are subjected to cratering. It is a figure explaining Example 1 to perform. FIG. 4A shows a state during consumable electrode arc welding of the two-electrode 1-torch system, in which the same reference numerals are given to the same functions shown in FIG. 4A, and description thereof will be omitted.

Then, as shown in FIG. 10B, when the leading wire tip 3a reaches the predetermined welding end vicinity position P1, the robot controller 27 shown in FIG. 3 causes the leading wire tip 3a to weld. The output of the position signal until reaching the end vicinity position P1 is completed, or the arrival at the position P1 is detected (hereinafter, it is determined that the position signal is reached), and the power supply device 23 for leading wire welding and the following The power supply device 24 for wire welding outputs a near-welding position current energization command signal. Then, the power supply device 23 for the preceding wire welding is
A leading wire welding near end position energizing current that is lower than the normal welding current is applied to the preceding wire 3, and the trailing wire welding power supply device 24 causes the following wire welding end near energizing current that is lower than the normal welding current value. Is applied to the trailing wire 4.
When the leading wire tip 3a reaches the welding end vicinity position P1, the robot controller 27 shown in FIG. 3 outputs a welding end vicinity position welding speed movement command signal to the manipulator 21. Then, since the manipulator 21 moves the welding torch 14 at the welding end vicinity position welding speed which is slower than the normal welding speed, the welding torch 14 moves at a low speed.

The above-mentioned energizing current near the end of the preceding wire welding, the energizing current near the end of the following wire welding, and the welding speed near the end of welding are the same as the amount of deposited metal per unit length as in normal welding. Is set in advance. Further, it is suitable that the position P1 near the end of welding is located at a distance from the end position P2 of welding within 5 times the distance L2 between the wire tips in the direction opposite to the welding direction.

Thereafter, as shown in FIG. 10C, when the leading wire tip 3a reaches the welding end position P2, the robot controller 27 shown in FIG.
Has reached the welding end position P2, and outputs a crater processing command signal to the preceding wire welding power source device 23 and the following wire welding power source device 24.

Then, as shown in FIG. 11A, the leading wire 3 and the trailing wire 4 finish the crater process and finish the welding. FIG. 11 shows the exhaustion 2 of the present invention following FIG.
It is a figure explaining Example 1 in which the preceding wire 3 and the following wire 4 are fed, and the preceding wire 3 and the following wire 4 perform the crater process in the electrode arc welding termination method.

As described above, in the first embodiment, since a current lower than the normal welding current value is applied to the leading wire 3 and the trailing wire 4 at the position P1 near the end of welding, the depression of the molten pool due to the arc force is reduced. However, since the welding torch 14 moves at a low speed, the amount of welding per unit length remains constant. Therefore, as shown in FIG. 11 (B), the recess 13 of the molten pool trace shown in FIG. 5 does not occur, and the appearance of the weld bead 9 is good. Also, the position P1 near the end of welding
Then, the manipulator 21 moves the welding torch 14 at a speed slower than the normal welding speed and energizes the trailing wire 4 with a current lower than the normal welding current value. Even if the row wires 4 simultaneously perform the crater treatment, the molten metal generated by the leading wire 3 fills the crater treatment traces generated by the trailing wire 4 to some extent. Almost no crater processing trace is generated, and only one crater processing trace is generated.

FIG. 12 is a diagram showing signals output by the robot controller 27 according to the first embodiment of the present invention and the moving speed of the welding torch 14. In the same figure, (A) shows the lapse of time t of the leading wire and trailing wire welding start command signals, and (B) shows the progress of the preceding wire and trailing wire welding end vicinity position current conduction command signals. The same figure (C) is shown.
Shows the progress t of the welding torch moving speed, and FIG. 7D shows the progress t of the leading wire and trailing wire crater processing command signals.

At time t1 in FIG. 12, the welding torch 14 moves to the welding start position, and the robot controller 27 causes the power supply device 23 for leading wire welding and the trailing wire welding as shown in FIG. A welding start command signal is output to the power supply device 24 and the energization of the leading wire 3 and the trailing wire 4 is started. Then, at time t2, when the leading wire tip 3a reaches the welding end vicinity position P1, the robot control device 27 shown in FIG. 3 determines that the leading wire tip 3a reaches the welding end vicinity position P1, and 12
As shown in (B), a welding end vicinity position current energization command signal is output to the preceding wire welding power supply device 23 and the following wire welding power supply device 24. Then, the preceding wire welding power source device 23 supplies the preceding wire 3 with a leading wire welding end vicinity energizing current lower than the normal welding current value,
The trailing wire welding power source device 24 supplies the trailing wire 4 with a passing current near the trailing wire welding end that is lower than the normal welding current value. Further, at the time t2, the robot control device 27 shown in FIG. 3 outputs a welding end vicinity position welding speed movement command signal to the manipulator 21, and FIG.
As shown in (C), the welding torch 14 moves at a low speed.

When the leading wire tip 3a reaches the welding end position P2 at time t3, the robot controller 27 shown in FIG. 3 causes the leading wire tip 3a to finish welding position P2 as shown in FIG. When the power supply device 23 for leading wire welding, the power supply device 24 for trailing wire welding, and the manipulator 21 are output, the leading wire and trailing wire crater processing command signals are output. As a result, the movement of the welding torch 14 is stopped, the leading wire and the trailing wire perform the crater process, and the welding is completed.

[Embodiment 2] FIG. 13 shows a method of terminating consumable two-electrode arc welding according to the present invention, in which the leading wire 3 and the trailing wire 4 are fed, and the trailing wire 4 performs the first and second crater treatments. It is a figure explaining Example 2 to perform. Same figure (A)
Is a state in which two-electrode one-torch method consumable electrode arc welding is being performed, and the same reference numerals are given to the same functions shown in FIG.

Then, as shown in FIG. 13B, when the leading wire tip 3a reaches the welding end vicinity position P1, the robot controller 27 shown in FIG. Upon determining that P1 has been reached, a welding end vicinity position current energization command signal is output to the preceding wire welding power supply device 23 and the following wire welding power supply device 24. Then, the power supply device 23 for the preceding wire welding is
A leading wire welding end position energizing current lower than a normal welding current value is applied to the leading wire 3, and the trailing wire welding power supply device 24 energizes a trailing wire welding end position energizing value lower than a normal welding current value. A current is applied to the trailing wire 4. Further, the leading wire tip 3a is positioned near the welding end position P1
Welding torch 14 moves at a low speed.

Then, as shown in FIG. 13C, when the leading wire tip 3a reaches the welding end position P2, the robot controller 27 shown in FIG.
Has reached the welding end position P2 and outputs a welding end command signal to the preceding wire welding power source device 23,
The first crater processing command signal is output to the trailing wire welding power supply device 24. The wire end-to-end distance L2 shown in FIG. 3B is the trailing wire first crater processing distance D1 described later.
Can be used as Then, as shown in FIG. 14 (A), the trailing wire 4 performs the first crater treatment while moving the welding torch 14 in the welding direction by the trailing wire first crater treatment distance D1. FIG. 14 is an embodiment 2 in which the leading wire 3 and the trailing wire 4 are fed and the trailing wire 4 performs the first and second crater treatments in the consumable two-electrode arc welding termination method of the present invention following FIG. 13. It is a figure explaining.

Here, the first crater process is to stop the feeding and energization of the leading wire 3 and energize only the trailing wire 4 to move the welding torch in the welding direction to carry out the welding end process. Is. The welding current value, the welding voltage value, and the welding speed in the first crater treatment period can be arbitrarily set, and the welding current value, the welding voltage value, and the welding speed for normal welding are lower than the values.

When the welding torch finishes moving the trailing wire first crater processing distance D1, for example, the wire tip distance L2, the welding torch 14 stops and the robot controller 27 shown in FIG. The second crater processing command signal is output to the power supply device for trailing wire welding 24, as shown in FIG.
As shown in (B), the trailing wire 4 performs the second crater process. Here, the second crater process is the trailing wire 4
Is to process the crater while stopping the movement of the welding torch 14, and the welding current value and the welding voltage value can be arbitrarily set. This corresponds to the crater processing described in Related Art 1.

Then, when the trailing wire 4 finishes the second crater process, the robot controller 27 shown in FIG.
Outputs a welding end command signal to the trailing wire welding power source device 24, and ends welding as shown in FIG. 14 (C).

As described above, in the second embodiment, since only the trailing wire 4 performs the crater processing described in the prior art 1 in the second crater processing, as shown in FIG. 15, there is only one crater processing trace 15. Does not happen. FIG. 15 is a diagram showing a welding end portion according to a second embodiment in the consumable two-electrode arc welding end method of the present invention. Further, at the position P1 near the end of welding, a current lower than the normal welding current value is applied to the leading wire 3 and the trailing wire 4, and the manipulator 21 moves the welding torch 14 at a speed slower than the normal welding speed. ,
The molten metal generated while moving the trailing wire 4 is pushed backward by the arc force, and this molten metal can fill the recessed molten pool by the arc force of the trailing wire 4. Therefore, as shown in FIG. 15, the weld pool trace 13 shown in FIG. 5 does not occur, and the appearance of the weld bead 9 is good.

FIG. 16 shows a robot controller 2 of the second embodiment.
It is a figure which shows the signal which 7 outputs, and the moving speed of the torch 14 for welding. In the same figure, (A) shows the elapsed time t of the leading wire and trailing wire welding start command signals,
FIG. 7B shows the progress t of the preceding wire and trailing wire welding near-end position current energization command signal, FIG. 6C shows the progress t of the welding torch moving speed, and FIG. The progress t of the wire welding end processing command signal is shown in FIG.
Shows the lapse t of the trailing wire first crater processing command signal, and FIG. 6F shows the lapse t of the trailing wire second crater processing command signal.

At time t1 in FIG. 16, the welding torch 14 moves to the welding start position, and the robot controller 27 causes the power source device 23 for leading wire welding and the trailing wire welding as shown in FIG. A welding start command signal is output to the power supply device 24 and the energization of the leading wire 3 and the trailing wire 4 is started. Then, at time t2, when the leading wire tip 3a reaches the welding end vicinity position P1, the robot control device 27 shown in FIG. 3 determines that the leading wire tip 3a reaches the welding end vicinity position P1, and 16
As shown in (B), a welding end vicinity position current energization command signal is output to the preceding wire welding power supply device 23 and the following wire welding power supply device 24. Then, the preceding wire welding power source device 23 supplies the preceding wire 3 with a leading wire welding end vicinity energizing current lower than the normal welding current value,
The trailing wire welding power source device 24 supplies the trailing wire 4 with a passing current near the trailing wire welding end that is lower than the normal welding current value. Further, at the time t2, the robot control device 27 shown in FIG. 3 outputs a welding end vicinity position welding speed movement command signal to the manipulator 21, and FIG.
As shown in (C), the manipulator 21 moves the welding torch 14 at the welding end vicinity position welding speed slower than the normal welding speed.

When the leading wire tip 3a reaches the welding end position P2 at time t3, the robot controller 27 shown in FIG. 3 causes the leading wire tip 3a to finish the welding end position P2 as shown in FIG. When it is determined that the preceding wire has been reached, a preceding wire welding end processing command signal is output to the preceding wire welding power supply device 23, and the feeding and energization of the preceding wire 3 are ended. Further, at the time t3, the robot control device 27 shown in FIG.
And the trailing wire first crater processing command signal is output to the manipulator 21, and the manipulator 21 moves the welding torch 14 at the trailing wire first crater processing moving speed slower than the normal welding speed to move the trailing wire. 4 performs the first crater process. Then, the welding torch 14 moves by the trailing wire first crater processing moving distance D1 and time t4.
3, the robot controller 27 shown in FIG. 3 outputs the trailing wire second crater processing command signal to the trailing wire welding power source device 24 and the manipulator 21, and the manipulator 21 stops the welding torch 14. The trailing wire 4 performs the second crater process. Then, at time t5, welding is completed.

[Embodiment 3] FIG. 17 shows the method of terminating consumable two-electrode arc welding according to the present invention, in which the leading wire 3 and the trailing wire 4 are fed, and the leading wire 3 performs the first and second crater treatments. It is a figure explaining Example 3. Same figure (A)
Is a state during consumable electrode arc welding of the two-electrode one-torch system, and the same reference numerals are given to the same functions shown in FIG.

Then, as shown in FIG. 17B, when the leading wire tip 3a reaches the welding end vicinity position P1, the robot controller 27 shown in FIG. Upon determining that P1 has been reached, a welding end vicinity position current energization command signal is output to the preceding wire welding power supply device 23 and the following wire welding power supply device 24. Then, the power supply device 23 for the preceding wire welding is
A leading wire welding end position energizing current lower than a normal welding current value is applied to the leading wire 3, and the trailing wire welding power supply device 24 energizes a trailing wire welding end position energizing value lower than a normal welding current value. A current is applied to the trailing wire 4. Further, the leading wire tip 3a is positioned near the welding end position P1.
Welding torch 14 moves at a low speed.

Then, as shown in FIG. 17C, when the leading wire tip 3a reaches the welding end position P2, the robot controller 27 shown in FIG.
Has reached the welding end position P2, and outputs a welding end command signal to the power supply device for trailing wire welding 24,
The preceding wire first crater processing command signal is output to the preceding wire welding power source device 23. The wire tip distance L2 shown in FIG. 17B can be used as a preceding wire first crater processing distance D2 described later.

FIG. 18 shows a method of terminating the consumable two-electrode arc welding of the present invention following FIG. 17, in which the leading wire 3 and the trailing wire 4 are fed, and the leading wire 3 performs the first and second crater treatments. It is a figure explaining Example 3. Then, as shown in FIG. 18 (A), the welding torch 14 moves the preceding wire first crater processing distance D in the direction opposite to the normal welding direction.
2. For example, the leading wire 3 performs the leading wire first crater process while moving the distance L2 between the wire tips. Then, when the welding torch 14 has finished moving the preceding wire first crater processing distance D2, for example, the wire tip distance L2, in the direction opposite to the normal welding direction, the welding torch 14 stops and is shown in FIG. The robot controller 27 outputs a leading wire second crater processing command signal to the leading wire welding power source device 23, and the leading wire 3 performs the second crater processing as shown in FIG. 18 (B).

Then, when the preceding wire 3 finishes the second crater process, the robot controller 27 shown in FIG.
Outputs a welding end command signal to the preceding wire welding power source device 23, and ends welding as shown in FIG. 18 (C).

As described above, in the third embodiment, since only the preceding wire 3 performs the crater processing described in the prior art 1 in the second crater processing, only one crater processing trace 15 is generated as shown in FIG. Absent. FIG. 19 is a view showing a welding end portion according to the third embodiment in the consumable two-electrode arc welding end method of the present invention. Further, at the position P1 near the end of welding, a current lower than the normal welding current value is applied to the leading wire 3 and the trailing wire 4, and the manipulator 21 moves the welding torch 14 at a speed slower than the normal welding speed. ,
The molten metal generated while moving the trailing wire 4 is pushed backward by the arc force, and this molten metal can fill the recessed molten pool by the arc force of the trailing wire 4. Therefore, as shown in FIG. 19, the weld pool trace 13 shown in FIG. 5 does not occur, and the appearance of the weld bead is good.

Further, even when the fillet welding of the bottom plate having the box-like shape of the object 8 to be welded shown in FIG. 20 and having the wall at the front of the welding end position P2 in the welding direction is performed, the leading wire 3 finishes welding. After reaching the position P2, after the energization of the trailing wire 4 is stopped, the leading wire 3 and the trailing wire 4 are moved in the direction opposite to the welding direction, and the leading wire 3 performs the first crater process, and the leading wire 3 Further, since the trailing wire 4 moves the first wire crater treatment distance D2 and the leading wire 3 performs the second crater treatment distance, it is possible to obtain a uniform weld bead 9 as shown in FIG. FIG. 20 shows that the welding object 8 has a box shape according to the welding termination method of the third embodiment.
It is a figure for demonstrating the case where fillet welding of a bottom plate is performed.

Further, according to the experiments by the inventors, when the molten pool is depressed to the extent that the molten pool trace 13 is formed as shown in FIG. 5 of the prior art 1, the molten metal of the preceding wire is depressed. In order to fill the pond, the leading wire 3 needs to be moved in the direction opposite to the welding direction with respect to the wire tip distance L2. Therefore, the preceding wire first crater processing distance D2
Is longer than the distance L2 between the wire tips.

FIG. 21 is a diagram showing signals output by the robot controller 27 of the third embodiment of the present invention and the moving speed of the welding torch 14. In the same figure, (A) shows the lapse of time t of the leading wire and trailing wire welding start command signals, and (B) shows the progress of the preceding wire and trailing wire welding end vicinity position current conduction command signals. The same figure (C) is shown.
Shows the progress t of the welding torch moving speed, and FIG. 6D shows the progress t of the preceding wire first crater processing command signal,
FIG. 6E shows the progress t of the preceding wire second crater processing command signal, and FIG. 6F shows the progress t of the trailing wire welding end processing command signal.

At time t1 in FIG. 21, the welding torch 14 moves to the welding start position, and the robot controller 27 causes the power source device 23 for leading wire welding and the trailing wire welding as shown in FIG. A welding start command signal is output to the power supply device 24 and the energization of the leading wire 3 and the trailing wire 4 is started. Then, at time t2, when the leading wire tip 3a reaches the welding end vicinity position P1, the robot control device 27 shown in FIG. 3 determines that the leading wire tip 3a reaches the welding end vicinity position P1, and 21
As shown in (B), a welding end vicinity position current energization command signal is output to the preceding wire welding power supply device 23 and the following wire welding power supply device 24. Then, the preceding wire welding power source device 23 supplies the preceding wire 3 with a leading wire welding end vicinity energizing current lower than the normal welding current value,
The trailing wire welding power source device 24 supplies the trailing wire 4 with a passing current near the trailing wire welding end that is lower than the normal welding current value. Further, at the time t2, the robot control device 27 shown in FIG. 3 outputs the welding end vicinity position welding speed movement command signal to the manipulator 21, and FIG.
As shown in (C), the manipulator 21 moves the welding torch 14 at the welding end vicinity position welding speed slower than the normal welding speed.

When the leading wire tip 3a reaches the welding end position P2 at time t3, the robot controller 27 shown in FIG. 3 causes the leading wire welding power source device 23 and the manipulator 21 to send the leading wire first crater processing command signal. 21C, the manipulator 21 moves the welding torch 14 in the direction opposite to the normal welding direction at the leading wire first crater processing moving speed slower than the normal welding speed. Then, the leading wire 3 performs the first crater process. Further, at time t3, FIG.
3, the robot controller 27 shown in FIG. 3 determines that the leading wire tip 3a has reached the welding end position P2, and sends the trailing wire welding end processing command signal to the trailing wire welding power supply device 24. Is output to terminate the feeding and energization of the trailing wire 4. Then, the welding torch 14 moves by the preceding wire first crater processing movement distance D2, and the time t
4, the robot control device 27 shown in FIG. 3 outputs the leading wire second crater processing command signal to the leading wire welding power source device 23 and the manipulator 21, and the manipulator 21 stops the welding torch 14 to advance. The wire 4 performs the second crater process. Then, at time t5, welding is completed.

[0053]

The consumable two-electrode arc welding ending method of the present invention according to claim 1 at the time of application is a normal welding at the welding end vicinity position P1 in the two-electrode one-torch method consumable electrode arc welding ending method. Since a current lower than the current value is applied to the leading wire 3 and the trailing wire 4, the depression of the molten pool due to the arc force is reduced, and the welding torch 14 moves at a low speed, so the welding amount per unit length Remains constant. Therefore, as shown in FIG. 11 (B), the recess 13 of the molten pool trace shown in FIG. 5 does not occur, and the appearance of the weld bead 9 is good. Also, the position P1 near the end of welding
Then, the manipulator 21 moves the welding torch 14 at a speed slower than the normal welding speed and energizes the trailing wire 4 with a current lower than the normal welding current value. Even if the row wires 4 simultaneously perform the crater treatment, the molten metal generated by the leading wire 3 fills the crater treatment traces generated by the trailing wire 4 to some extent. Almost no crater processing trace is generated, and only one crater processing trace is generated.

Consumption 2 of the present invention according to claim 2 at the time of application
The electrode arc welding ending method is a method of ending the consumable electrode arc welding of the two-electrode one-torch method, in which a current lower than the normal welding current value is applied to the leading wire 3 and the trailing wire 4 at the position P1 near the welding end, Since the welding torch 14 is moved at a speed slower than the normal welding speed, the molten metal generated while moving the trailing wire 4 is pushed backward by the arc force, and the molten metal is arced by the trailing wire 4. The force can fill the recessed molten pool. Therefore, the weld pool trace 1 generated by the conventional technique at the welding end position
3 does not occur, the appearance of the weld bead is good, and defects such as cracks and shrinkage holes do not occur. Also,
At the welding end position P2, the feeding and energization of the leading wire 3 are stopped, the first crater process is performed on the trailing wire 4 at a welding speed slower than that during normal welding, and then the movement of the welding torch is substantially stopped. Since the second crater process is performed by the second crater process, there is only one crater process trace, and even at the welding end position,
The appearance of the weld bead 9 is improved and the weld joint strength can be secured without decreasing the weld bead width or causing insufficient penetration.

Consumption of the present invention according to claim 3 at the time of application 2
The electrode arc welding ending method is a method of ending the consumable electrode arc welding of the two-electrode one-torch method, in which a current lower than the normal welding current value is applied to the leading wire 3 and the trailing wire 4 at the position P1 near the welding end, Since the welding torch 14 is moved at a speed slower than the normal welding speed, the molten metal generated while moving the trailing wire 4 is pushed backward by the arc force, and the molten metal is arced by the trailing wire 4. The force can fill the recessed molten pool. Therefore, the weld pool trace 1 generated by the conventional technique at the welding end position
3 does not occur, the appearance of the weld bead 9 is good, and defects such as cracks and shrinkage holes do not occur. Also,
At the welding end position P2, the feeding and energization of the trailing wire 4 are stopped, and the welding torch 14 is moved at a welding speed slower than that at the time of normal welding in the direction opposite to the welding speed to move the leading wire 3
The first crater process is performed only by using the first crater process, and thereafter, the movement of the welding torch 14 is substantially stopped and the second crater process is performed. Therefore, only one crater process mark is left, and the welding bead width is reduced at the welding end position. The appearance of the weld bead 9 is improved without any decrease or insufficient melting, and the weld joint strength can be secured. Further, even when the fillet welding of the bottom plate having the box-shaped object 8 to be welded and having the wall at the front of the welding end position P2 in the welding direction is performed, the uniform weld bead 9 can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram best representing the features of the invention according to the present application.

FIG. 2 is a diagram illustrating a consumable electrode arc welding ending method of a two-electrode one-torch method.

FIG. 3 is a diagram showing a general configuration of a two-electrode one-torch welding robot.

FIG. 4 is a diagram illustrating a method of terminating the consumable electrode arc welding of the two-electrode one-torch method of the related art 1.

5 is a diagram illustrating a method of terminating the consumable electrode arc welding of the two-electrode one-torch method of the related art 1 following FIG.

FIG. 6 is a view showing an apparatus for performing tandem arc welding of Prior Art 2.

FIG. 7 is a time chart explaining a control method at the end of welding according to the related art 2.

FIG. 8 is a diagram for explaining a case where the object to be welded 8 has a box shape and fillet welding of the bottom plate is performed.

FIG. 9 is a diagram for explaining that the welding bead 9 is uneven at the welding end position P2 in the case of performing fillet welding of the bottom plate when the shape of the object to be welded 8 is box-shaped according to Conventional Technique 2. .

FIG. 10 is a first embodiment in which the leading wire 3 and the trailing wire 4 are fed and the leading wire 3 and the trailing wire 4 perform crater treatment in the consumable two-electrode arc welding termination method of the present invention.
It is a figure explaining.

FIG. 11 shows Example 1 in which the leading wire 3 and the trailing wire 4 are fed and the leading wire 3 and the trailing wire 4 perform the crater treatment in the consumable two-electrode arc welding termination method of the present invention following FIG. 10. It is a figure explaining.

FIG. 12 is a diagram showing a signal output by the robot controller 27 and a moving speed of the welding torch 4 according to the first embodiment of the present invention.

FIG. 13 is a diagram for explaining a second embodiment in which the leading wire 3 and the trailing wire 4 are fed and the trailing wire 4 performs the first and second crater treatments in the consumable two-electrode arc welding termination method of the present invention. Is.

FIG. 14 is an embodiment 2 in which the leading wire 3 and the trailing wire 4 are fed and the trailing wire 4 performs the first and second crater treatments in the consumable two-electrode arc welding termination method of the present invention following FIG. It is a figure explaining.

FIG. 15 is a diagram showing a welding end portion according to a second embodiment in the consumable two-electrode arc welding end method of the present invention.

FIG. 16 is a diagram showing a signal output by the robot controller 27 and a moving speed of the welding torch 4 according to the second embodiment.

FIG. 17 is a diagram for explaining a third embodiment in which the leading wire 3 and the trailing wire 4 are fed and the leading wire 3 performs the first and second crater treatments in the consumable two-electrode arc welding termination method of the present invention. is there.

FIG. 18 shows Example 3 in which, in the consumable two-electrode arc welding termination method of the present invention following FIG. 17, the preceding wire 3 and the following wire 4 are fed, and the preceding wire 3 performs the first and second crater treatments. It is a figure explaining.

FIG. 19 is a diagram showing a welding end portion according to a third embodiment in the consumable two-electrode arc welding end method of the present invention.

FIG. 20 is a diagram showing an object to be welded 8 according to the welding termination method of the third embodiment.
Is a box-like shape, and is a diagram for explaining a case where fillet welding of the bottom plate is performed.

FIG. 21 is a diagram showing a signal output by the robot controller 27 and a moving speed of the welding torch 14 according to the third embodiment of the present invention.

[Explanation of symbols]

1 Leading Tip 2 Trailing Tip 3 Leading Wire 3a Leading Wire Tip 4 Trailing Wire 4a Trailing Wire Tip 5, 6 Arc 7 Molten Pool 8 Welding Object 9 Weld Bead 10 Nozzle 11 Shield Gas 13 Molten Pool Trace 14 Welding Torch 15, 16 Crater processing trace 21 Manipulator 23 Power supply device for leading wire welding 24 Power supply device for trailing wire welding 25 Leading wire feeding device 26 Trailing wire feeding device 27 Robot controller 41 (Prior art 2) Leading tip 42 ( Prior Art 2) Trailing Tip 44 (Prior Art 2) Power Supply Device 45 for Leading Wire Welding (Prior Art 2) Power Supply Device 46 for Trailing Wire Welding (Prior Art 2) Leading Wire Feeding Device 47 (Prior Art 2) Row wire feeder 48 (Prior art 2) Lead wire 49 (Prior art 2) Trailing wires 50, 51 (Prior art 2) Arc 52 ( Prior art 2) Weld pool 53 (Conventional art 2) Weld bead 54 Welding controller 55 Welding robot D1 Trailing wire first crater treatment distance D2 Leading wire first crater treatment distance L1 Welding end position P2 and welding end vicinity position P1 Distance L2 Distance between wire tips P1 Welding end position P2 Welding end position

Claims (3)

[Claims] 1. A consumable two-electrode arc welding ending method of feeding and welding two wires in one torch, wherein the current applied to the preceding wire and the following wire at a position near the end of welding is higher than that of a normal welding current. To a low current and the welding torch is moved in the welding direction at a speed slower than the normal welding speed, the movement of the welding torch is stopped at the welding end position, and the preceding wire and the trailing wire perform crater processing. Consumption 2
How to finish electrode arc welding. 2. In a consumable two-electrode arc welding ending method of feeding and welding two wires in one torch, the current applied to the leading wire and the trailing wire at a position near the end of welding is changed from a normal welding current. Low current to move the welding torch in the welding direction at a speed slower than the normal welding speed, and stop feeding and energizing the preceding wire at the welding end position,
While moving the welding torch in the welding direction at a speed slower than the normal welding speed by the trailing wire first crater treatment distance, the trailing wire performs the first crater treatment, and then moves the welding torch. A consumable two-electrode arc welding ending method in which the trailing wire is stopped and the second crater process is performed. 3. In a consumable two-electrode arc welding termination method of feeding and welding two wires in one torch, the current applied to the preceding wire and the trailing wire at a position near the end of welding is set to be lower than the normal welding current. Low current to move the welding torch in the welding direction at a speed slower than the normal welding speed, and stop feeding and energizing the trailing wire at the welding end position,
The preceding wire performs the first crater treatment while moving the welding torch in the direction opposite to the normal welding direction at a speed slower than the normal welding speed by the first crater treatment distance, and then for the welding. A consumable two-electrode arc welding ending method in which the movement of the torch is stopped and the preceding wire performs the second crater treatment.