JP2023172539A - Arc welding method and arc welding device - Google Patents

Abstract

To secure arc stability in a reverse polarity period, and suppress occurrence of an irregular short circuit.SOLUTION: In a first step, a welding wire W1 is fed at first feeding speed WF1 in a reverse polarity period Tep. In a second step, feeding speed WF of the welding wire W1 is changed to second feeding speed WF2 larger than the first feeding speed WF1, when performing communication from the reverse polarity period Tep to a positive polarity period Ten. In a third step, the welding wire W1 is fed at the second feeding speed WF2, in the positive polarity period Ten. In a fourth step, the feeding speed WF of the welding wire W1 is changed to the first feeding speed WF1, before performing communication from the positive polarity period Ten to the reverse polarity period Tep.SELECTED DRAWING: Figure 2

Description

The present invention relates to an arc welding method and an arc welding device.

Patent Document 1 discloses a feed control method for consumable electrode AC arc welding in which welding is performed by alternately switching the voltage applied to the arc between reverse polarity (electrode positive polarity) and positive polarity (electrode negative polarity). There is.

Patent No. 5090765

By the way, in the positive polarity period, the melting efficiency of the welding wire is high, while in the reverse polarity period, the melting characteristics of the welding wire tend to be inferior to that in the positive polarity period. Therefore, in the positive polarity period, it is preferable to increase the welding wire feeding speed to increase the amount of welding wire deposited, and in the reverse polarity period, it is preferable to reduce the welding wire feeding speed.

In the invention of Patent Document 1, the feeding speed of the welding wire is changed simultaneously with the commutation from the reverse polarity period to the positive polarity period and at the same time as the commutation from the positive polarity period to the reverse polarity period.

However, in the invention of Patent Document 1, immediately after the commutation from the positive polarity period to the reverse polarity period, the feeding speed of the welding wire is maintained at a high state, and the excessively grown droplets are fed at high speed. Irregular short circuits may occur, making the arc unstable and increasing spatter.

The present invention has been made in view of this point, and its purpose is to ensure arc stability during the reverse polarity period and to suppress the occurrence of irregular short circuits.

A first invention provides a reverse polarity period in which a welding wire, which is a consumable electrode, is fed toward a base metal, and the welding wire is a positive electrode and the base metal is a negative electrode, and a period in which the welding wire is a negative electrode and the base metal is Welding is performed by generating an arc between the welding wire and the base metal by passing a welding current through the welding wire and the base metal such that a positive polarity period, which is a positive electrode, is alternately repeated. The arc welding method includes a first step of feeding the welding wire at a first feeding speed during the reverse polarity period, and a step of feeding the welding wire at a first feeding speed during the reverse polarity period, and a step of feeding the welding wire at a first feeding speed during the reverse polarity period. a second step of changing the feeding speed to a second feeding speed larger than the first feeding speed; and a third step of feeding the welding wire at the second feeding speed during the positive polarity period. and a fourth step of changing the feeding speed of the welding wire to the first feeding speed before the time of commutation from the positive polarity period to the reverse polarity period.

In the first invention, by increasing the feeding speed of the welding wire during the positive polarity period when the welding wire has high melting efficiency, the amount of welding wire deposited can be increased and high-deposition AC welding can be realized.

In addition, by reducing the feeding speed of the welding wire before commutation in the reverse polarity period, where the melting characteristics of the welding wire are inferior to the positive polarity period, arc stability during the reverse polarity period is ensured and irregular It is possible to suppress the occurrence of short circuits.

A second invention is the arc welding method according to the first invention, in which, in the fourth step, the feeding speed of the welding wire is abruptly changed from the second feeding speed to the first feeding speed.

In the second invention, by sharply lowering the feeding speed of the welding wire, it is possible to reduce the risk of short circuit occurring during the reverse polarity period and suppress the occurrence of spatter.

A third invention is the arc welding method according to the first invention, in which the fourth step changes the feeding speed of the welding wire from the second feeding speed to a value smaller than the second feeding speed and the second feeding speed. a fifth step of changing the first feeding speed to a third feeding speed and feeding the welding wire at the third feeding speed; and after the fifth step, feeding the welding wire; a sixth step of changing the speed from the third feeding speed to the first feeding speed.

In the third invention, the feeding speed of the welding wire is lowered stepwise in the order of the second feeding speed, the third feeding speed, and the first feeding speed. Compared to the case where the speed is lowered steeply, the amount of welding wire fed can be increased, and the amount of welding wire deposited can be further increased.

A fourth invention is the arc welding method according to the first invention, wherein in the fourth step, the feeding speed of the welding wire is gradually decreased from the second feeding speed to the first feeding speed. change to

In the fourth invention, by gradually decreasing the welding wire feeding speed, the stability of the arc is improved compared to the case where the welding wire feeding speed is sharply lowered.

A fifth invention is the arc welding method according to the first invention, in which the fourth step changes the feeding speed of the welding wire from the second feeding speed to a fourth feeding speed smaller than the first feeding speed. a seventh step of changing the feeding speed to the fourth feeding speed and feeding the welding wire at the fourth feeding speed; and after the seventh step, changing the feeding speed of the welding wire from the fourth feeding speed; and an eighth step of changing the feeding speed to the first feeding speed.

In the fifth invention, by once lowering the welding wire feeding speed below the first feeding speed, it is possible to further reduce the risk of short circuits and suppress the occurrence of spatter.

A sixth invention is an arc welding device for welding by generating an arc between a welding wire, which is a consumable electrode, and a base metal, the welding wire having a reverse polarity period in which the welding wire is a positive electrode and the base metal is a negative electrode. , a power converter for passing a welding current between the welding wire and the base material so that a positive polarity period in which the welding wire is a negative electrode and the base metal is a positive electrode are alternately repeated; and the welding wire. a wire feeding section that feeds the welding wire toward the base metal; and a control section that controls the operation of the wire feeding section to change the feeding speed of the welding wire, and the control section In the polarity period, a first operation of feeding the welding wire at a first feeding speed, and when commutation from the reverse polarity period to the positive polarity period, the feeding speed of the welding wire is changed to the first operation. a second operation of changing the feeding speed to a second feeding speed larger than the feeding speed; a third operation of feeding the welding wire at the second feeding speed during the positive polarity period; A fourth operation of changing the feeding speed of the welding wire to the first feeding speed is performed before the time of commutation in the reverse polarity period.

In the sixth invention, by increasing the feeding speed of the welding wire during the positive polarity period when the welding wire has high melting efficiency, it is possible to increase the amount of welding wire deposited and realize high welding AC welding.

In addition, by reducing the welding wire feeding speed before commutation in the reverse polarity period, where the welding wire's melting characteristics are inferior to the positive polarity period, arc stability during the reverse polarity period is ensured and irregular It is possible to suppress the occurrence of short circuits.

According to the present invention, it is possible to ensure arc stability during the reverse polarity period and to suppress the occurrence of irregular short circuits.

FIG. 1 is a schematic configuration diagram of an arc welding apparatus according to the first embodiment. FIG. 3 is a diagram showing a waveform of a welding current and a waveform of a welding wire feeding speed. 7 is a diagram showing a waveform of a welding current and a waveform of a welding wire feeding speed in Embodiment 2. FIG. 7 is a diagram showing a waveform of a welding current and a waveform of a welding wire feeding speed in Embodiment 3. FIG. FIG. 7 is a diagram showing a waveform of a welding current and a waveform of a welding wire feeding speed in the fourth embodiment.

Embodiments of the present invention will be described below based on the drawings. Note that the following description of preferred embodiments is essentially just an example, and is not intended to limit the present invention, its applications, or its uses.

《Embodiment 1》
As shown in FIG. 1, the arc welding apparatus 1 welds the base material B1 by generating an arc A1 between the welding wire W1, which is a consumable electrode, and the base material B1.

The arc welding device 1 includes a welding unit 10, a wire feeding section 21, a welding torch 22, and a setting section 25.

The wire feeding unit 21 feeds the welding wire W1 toward the base material B1. Specifically, the wire feeding section 21 feeds the welding wire W1 to the welding torch 22. Welding torch 22 holds welding wire W1 so that welding wire W1 fed from wire feeder 21 and base metal B1 face each other.

Welding torch 22 has a welding tip 22a. Welding tip 22a supplies power from welding unit 10 to welding wire W1. The wire feeding section 21 is provided with a feeding speed detection section (not shown) that detects the feeding speed WF of the welding wire W1. Welding torch 22 is held by a robot (not shown). A detection signal indicating the feeding speed WF of the welding wire W1 detected by the feeding speed detection section is transmitted to the control section 14. The robot moves the welding torch 22 at a predetermined welding speed along a predetermined welding target area in the base material B1.

Setting section 25 is used to set welding conditions including welding current and welding voltage. Specifically, the setting unit 25 sets a set welding current for welding, a set welding voltage for welding, a feeding speed of welding wire W1, a type of shielding gas, a material of welding wire W1, and a set welding voltage for welding. Set the diameter, pulse welding period, number of pulse outputs, etc.

The welding unit 10 includes a power conversion section 11, a welding current detection section 12, a welding voltage detection section 13, and a control section 14.

Power converter 11 is electrically connected to power source S1. The power converter 11 generates a welding voltage V suitable for welding using the power supplied from the power source S1. Power converter 11 is electrically connected to welding wire W1 via welding tip 22a of welding torch 22. The power converter 11 is electrically connected to the base material B1. Power converter 11 applies welding voltage V between welding wire W1 and base material B1, thereby causing welding current I to flow between welding wire W1 and base material B1.

The power converter 11 includes a first rectifier 101 , a first switch 102 , a transformer 103 , a second rectifier 104 , a reactor 105 , and a second switch 106 .

The first rectifier 101 rectifies the output of the power source S1. The first switching section 102 adjusts the output of the first rectifying section 101 by a switching operation. The transformer 103 converts the output of the first switching unit 102 into an output suitable for welding.

The second rectifier 104 rectifies the output of the transformer 103. The reactor 105 is connected in series with the second rectifier 104 and smoothes the output of the second rectifier 104. The second switching unit 106 adjusts the output of the reactor 105 by a switching operation. The output of the second switching unit 106 is supplied to the welding wire W1 and the base material B1 via the welding tip 22a of the welding torch 22.

As a result, welding voltage V is applied between welding wire W1 and base metal B1, and welding current I flows between welding wire W1 and base metal B1. As will be described in detail later, the power converter 11 has a reverse polarity period Tep in which the welding wire W1 is a positive electrode and the base material B1 is a negative electrode, and a positive polarity period Ten in which the welding wire W1 is a negative electrode and the base material B1 is a positive electrode. A welding current I is passed between the welding wire W1 and the base material B1 so that the welding current I is alternately repeated.

Welding current detection section 12 detects welding current I. Welding voltage detection section 13 detects welding voltage V. A detection signal indicating welding current I detected by welding current detection section 12 and a detection signal indicating welding voltage V detected by welding voltage detection section 13 are transmitted to control section 14 .

The control section 14 transmits signals between each section of the welding unit 10 and a device outside the welding unit 10. In the example shown in FIG. 1, the parts of the welding unit 10 that transmit signals to the control part 14 are the first switching part 102, the second switching part 106, the welding current detection part 12, and the welding voltage detection part 13. Devices external to the welding unit 10 that transmit signals to the control section 14 are a wire feeding section 21 and a setting section 25.

The control unit 14 controls each part of the welding unit 10 and devices external to the welding unit 10 based on signals transmitted from each part of the welding unit 10 and devices external to the welding unit 10.

The control unit 14 controls the operation of the wire feeding unit 21 to change the feeding speed WF of the welding wire W1. Specifically, the control unit 14 controls the feeding speed of the welding wire W1 in the wire feeding unit 21 according to the set current of the welding current I set by the setting unit 25. Here, the feeding speed WF and the welding current I have a mutual correlation. More specifically, the average welding speed (also referred to as feed amount) as a moving average and the average welding current (also referred to as set current) that is an average current as a moving average are in a mutually correlated relationship.

The control unit 14 controls the first switching unit 102 and the second switching unit 106 of the power conversion unit 11, the wire feeding unit 21, and a robot (not shown) that holds the welding torch 22.

The control unit 14 includes, for example, a processor and a memory electrically connected to the processor. Memory stores programs and information for operating the processor.

<How to control arc welding equipment>
Next, the operation of the arc welding device 1 will be explained. The arc welding apparatus 1 supplies a shielding gas from a gas supply port (not shown) to shield the welding location of the base material B1 from the outside air, and supplies a current between the welding wire W1 and the base material B1.

As a result, an arc A1 is generated between the welding wire W1 and the base material B1, and the heat of the arc A1 melts the tip of the welding wire W1 and a part of the base material B1. The melted welding wire W1 becomes a droplet and drips onto the base material B1, forming a molten pool together with a portion of the base material B1 melted by the heat of the arc A1.

The welding torch 22 moves in the welding direction with respect to the base material B1, for example, while performing a spiral weaving operation. A bead is formed on the base material B1 as the welding torch 22 moves, and the base material B1 is welded.

FIG. 2 is a diagram showing a waveform of a welding current and a waveform of a welding wire feeding speed. In FIG. 2, the vertical axis shows welding current I and feed rate WF, and the horizontal axis shows time. In pulse welding, welding current I is set to 200A, for example.

The arc welding device 1 constitutes a consumable electrode type AC pulse arc welding machine. The welding current I is controlled such that a reverse polarity period Tep and a positive polarity period Ten are alternately repeated.

The arc welding device 1 sets the feeding speed WF of the welding wire W1 based on the magnitude of the set welding current I. Based on this feeding speed WF, various pulse parameters constituting the AC pulse waveform are set.

Here, as shown in FIG. 2, the pulse parameters include a peak current value Ip in the reverse polarity period Tep, a base current value Ib, a peak current period Tp, a base current period Tb, a positive polarity period Ten, and a The positive polarity current value Ien, etc.

The period from time t1 to time t3 is a reverse polarity period Tep of the reverse polarity region EP(+). In the reverse polarity period Tep, the welding current I is controlled so that the welding wire W1 becomes a positive electrode and the base material B1 becomes a negative electrode.

In the reverse polarity period Tep, a first step of feeding the welding wire W1 at a first feeding speed WF1 is performed. Specifically, the control unit 14 performs a first operation of feeding the welding wire W1 at the first feeding speed WF1 during the reverse polarity period Tep by changing the feeding speed WF of the wire feeding unit 21. .

At time t1, welding current I changes to peak current value Ip. The period from time t1 to time t2 is a peak current period Tp. During the peak current period Tp, the welding current I is maintained at the peak current value Ip.

At time t2, the absolute value of welding current I changes sharply from peak current value Ip to base current value Ib. The period from time t2 to time t3 is a base current period Tb. During the base current period Tb, the welding current I is maintained at the base current value Ib.

At time t3, the current is commutated from the reverse polarity period Tep of the reverse polarity region EP(+) to the positive polarity period Ten of the positive polarity region EN(-).

When commutating from the reverse polarity period Tep to the positive polarity period Ten, a second step is performed in which the feeding speed WF of the welding wire W1 is changed to a second feeding speed WF2 larger than the first feeding speed WF1. Specifically, the control unit 14 changes the feeding speed WF of the welding wire W1 when commutating from the reverse polarity period Tep to the positive polarity period Ten by changing the feeding speed WF of the wire feeding unit 21. , performs a second operation of changing the first feeding speed WF1 to a second feeding speed WF2 larger than the first feeding speed WF1.

The period from time t3 to time t5 is a positive polarity period Ten of the positive polarity region EN(-). In the positive polarity period Ten, the welding current I is controlled so that the welding wire W1 becomes a negative electrode and the base material B1 becomes a positive electrode. During the positive polarity period Ten, the welding current I is maintained at the positive current value Ien.

In the positive polarity period Ten, a third step of feeding the welding wire W1 at a second feeding speed WF2 is performed. Specifically, the control unit 14 performs a third operation of controlling the feeding speed WF of the welding wire W1 and feeding the welding wire W1 at the second feeding speed WF2 during the positive polarity period Ten.

In the example shown in FIG. 2, at time t5, the current is commutated from the positive polarity period Ten of the positive polarity region EN(-) to the reverse polarity period Tep of the reverse polarity region EP(+). In the positive polarity period Ten, the feeding speed of the welding wire W1 is set to the second feeding speed WF2, and by increasing the feeding amount of the welding wire W1, the amount of welding is increased.

However, for example, if the feeding speed WF of the welding wire W1 is changed from the second feeding speed WF2 to the first feeding speed WF1 at the same time as the commutation from the positive polarity period Ten to the reverse polarity period Tep, the positive polarity period Ten Immediately after the commutation from to the reverse polarity period Tep, the feeding speed WF of the welding wire W1 remains high, and irregular short circuits occur because the excessively grown droplets are fed at high speed. There is a risk that the arc will become unstable and spatter will increase.

Therefore, in the present embodiment, the feeding speed WF of the welding wire W1 is changed at time t4, which is a predetermined time before the time t5 when the current flows from the positive polarity period Ten to the reverse polarity period Tep. For example, when the positive polarity period Ten is 1000 μsec to 2000 μsec, the predetermined time between time t4 and time t5 may be about 100 μsec to 200 μsec.

At time t4, which is before time t5 when the current changes from the positive polarity period Ten to the reverse polarity period Tep, a fourth step of changing the feeding speed of the welding wire W1 to the first feeding speed WF1 is performed. Specifically, the control unit 14 performs a fourth operation of changing the feeding speed WF of the wire feeding unit 21 and changing the feeding speed of the welding wire W1 to the first feeding speed WF1 at time t4. .

In the fourth step, the feeding speed WF of the welding wire W1 is abruptly changed from the second feeding speed WF2 to the first feeding speed WF1. Thereby, the risk of short circuit occurring during the reverse polarity period Tep can be reduced, and the occurrence of spatter can be suppressed. After the fourth step, the welding wire W1 is fed at the first feeding speed WF1 during a period from time t4 to time t5.

The arc welding device 1 generates an arc A1 between the welding wire W1 and the base metal B1 by repeating the first step to the fourth step, and the heat of the arc A1 causes a droplet to form at the tip of the welding wire W1. is formed and a part of the base material B1 is melted.

The droplets formed at the tip of the welding wire W1 move from the tip of the welding wire W1 to the base material B1 and adhere to the base material B1 by droplet transfer, forming a molten pool on the base material B1. In this way, the transfer of the droplet does not cause a short circuit between the welding wire W1 and the base metal B1, the arc A1 is generated continuously at the peak current and the base current, and the droplet formed at the tip of the welding wire W1 is One droplet transfers to the base material B1 for each pulse of one peak current, leaving the tip of the welding wire W1 in the air and transferring to the base material B1 so that one droplet per pulse transfers to the base material B1. do.

-Effects of Embodiment 1-
According to the arc welding apparatus 1 according to the first embodiment, in the positive polarity period Ten in which the melting efficiency of the welding wire W1 is high, the amount of welding of the welding wire W1 is increased by increasing the feeding speed of the welding wire W1, High-adhesion AC welding can be achieved.

In addition, arc stability during the reverse polarity period Tep is ensured by reducing the feeding speed of the welding wire W1 before commutation to the reverse polarity period Tep, in which the melting characteristics of the welding wire W1 are inferior to the positive polarity period Ten. At the same time, it is possible to suppress the occurrence of irregular short circuits.

Furthermore, by sharply lowering the feeding speed WF of the welding wire W1 from the second feeding speed WF2 to the first feeding speed WF1, the risk of short circuit occurring during the reverse polarity period Tep is reduced, and the occurrence of spatter is reduced. It can be suppressed.

《Embodiment 2》
Hereinafter, the same parts as in the first embodiment will be denoted by the same reference numerals, and only the differences will be explained.

As shown in FIG. 3, a fourth step of changing the feeding speed WF of the welding wire W1 to the first feeding speed WF1 is performed before the time t5 when the current changes from the positive polarity period Ten to the reverse polarity period Tep. . The fourth step includes a fifth step performed in a period from time t4' to time t4, which is before time t4, and a sixth step performed in a period from time t4 to time t5.

In the fifth step, the feeding speed WF of the welding wire W1 is changed from the second feeding speed WF2 to a third feeding speed WF3 that is smaller than the second feeding speed WF2 and larger than the first feeding speed WF1. and feeds the welding wire W1 at a third feeding speed WF3.

In the sixth step, after the fifth step, the feeding speed WF of the welding wire W1 is changed from the third feeding speed WF3 to the first feeding speed WF1, and the welding wire W1 is fed at the first feeding speed WF1. send.

In this way, before the time t5 when the current flows from the positive polarity period Ten to the reverse polarity period Tep, the feeding speed WF of the welding wire W1 is changed to the second feeding speed WF2, the third feeding speed WF3, the first feeding speed WF3, and the first feeding speed WF3. By lowering the feed rate WF1 step by step, the feed rate of the welding wire W1 can be increased compared to the case where the feed rate is lowered steeply from the second feed rate WF2 to the first feed rate WF1. The amount of welding of the wire W1 can be further increased.

《Embodiment 3》
As shown in FIG. 4, a fourth step of changing the feeding speed WF of the welding wire W1 to the first feeding speed WF1 is performed before the time t5 when the current changes from the positive polarity period Ten to the reverse polarity period Tep. .

In the fourth step, the feeding speed WF of the welding wire W1 is changed so as to gradually decrease from the second feeding speed WF2 to the first feeding speed WF1. In the example shown in FIG. 4, the waveform of the feeding speed WF of the welding wire W1 slopes diagonally downward from time t4 to time t5.

In this way, by gradually reducing the feeding speed WF of the welding wire W1, the stability of the arc is improved compared to the case where the feeding speed WF of the welding wire W1 is lowered steeply.

《Embodiment 4》
As shown in FIG. 5, a fourth step of changing the feeding speed WF of the welding wire W1 to the first feeding speed WF1 is performed before the time t5 when the current changes from the positive polarity period Ten to the reverse polarity period Tep. .

The fourth step includes a seventh step performed in a period from time t4' to time t4, which is before time t4, and an eighth step performed in a period from time t4 to time t5.

In the seventh step, the feeding speed WF of the welding wire W1 is changed from the second feeding speed WF2 to a fourth feeding speed WF4 smaller than the first feeding speed WF1, and the welding wire W1 is fed to the fourth feeding speed WF4. Feed at speed WF4.

In the eighth step, after the seventh step, the feeding speed WF of the welding wire W1 is changed from the fourth feeding speed WF4 to the first feeding speed WF1.

In this way, by once lowering the feeding speed WF of the welding wire W1 below the first feeding speed WF1, it is possible to further reduce the risk of short circuiting and suppress the occurrence of spatter.

As explained above, the present invention has the highly practical effect of ensuring arc stability during the reverse polarity period and suppressing the occurrence of irregular short circuits, and is therefore extremely useful and industrially effective. The availability of the above is high.

1 Arc welding device 11 Power conversion section 14 Control section 21 Wire feeding section A1 Arc B1 Base material Tep Reverse polarity period Ten Positive polarity period W1 Welding wire WF1 First feed speed WF2 Second feed speed WF3 Third feed speed WF4 4th feed speed

Claims (6)

A welding wire, which is a consumable electrode, is fed toward the base metal, and a reverse polarity period in which the welding wire is a positive electrode and the base metal is a negative electrode, and a positive polarity period in which the welding wire is a negative electrode and the base metal is a positive electrode. An arc welding method for welding by generating an arc between the welding wire and the base metal by passing a welding current through the welding wire and the base metal such that and are repeated alternately, ,
a first step of feeding the welding wire at a first feeding speed during the reverse polarity period;
A second step of changing the feeding speed of the welding wire to a second feeding speed larger than the first feeding speed when commutating from the reverse polarity period to the positive polarity period;
a third step of feeding the welding wire at the second feeding speed during the positive polarity period;
A fourth step of changing the feeding speed of the welding wire to the first feeding speed before the time of commutation from the positive polarity period to the reverse polarity period. The arc welding method according to claim 1,
In the fourth step, the arc welding method includes abruptly changing the feeding speed of the welding wire from the second feeding speed to the first feeding speed. The arc welding method according to claim 1,
The fourth step is
The feeding speed of the welding wire is changed from the second feeding speed to a third feeding speed that is smaller than the second feeding speed and larger than the first feeding speed, and the welding wire is fed at the second feeding speed. a fifth step of feeding at a third feeding speed;
The arc welding method includes a sixth step of changing the feeding speed of the welding wire from the third feeding speed to the first feeding speed after the fifth step. The arc welding method according to claim 1,
In the fourth step, the arc welding method includes changing the feeding speed of the welding wire so that it gradually decreases from the second feeding speed to the first feeding speed. The arc welding method according to claim 1,
The fourth step is
A feeding speed of the welding wire is changed from the second feeding speed to a fourth feeding speed smaller than the first feeding speed, and the welding wire is fed at the fourth feeding speed. 7 steps and
The arc welding method includes an eighth step of changing the feeding speed of the welding wire from the fourth feeding speed to the first feeding speed after the seventh step. An arc welding device that generates an arc between a welding wire, which is a consumable electrode, and a base metal to weld,
The welding wire and the base material are connected so that a reverse polarity period in which the welding wire is a positive electrode and the base metal is a negative electrode and a positive polarity period in which the welding wire is a negative electrode and the base metal is a positive electrode are alternately repeated. a power conversion section that passes welding current between the material and the material;
a wire feeding unit that feeds the welding wire toward the base metal;
comprising a control unit that controls the operation of the wire feeding unit to change the feeding speed of the welding wire,
The control unit includes:
a first operation of feeding the welding wire at a first feeding speed during the reverse polarity period;
a second operation of changing the feeding speed of the welding wire to a second feeding speed larger than the first feeding speed when commutating from the reverse polarity period to the positive polarity period;
a third operation of feeding the welding wire at the second feeding speed during the positive polarity period;
An arc welding apparatus that performs a fourth operation of changing the feeding speed of the welding wire to the first feeding speed before the time of commutation from the positive polarity period to the reverse polarity period.

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