TWI503197B - Arc welding method - Google Patents

Description

Arc welding method

The present invention relates to an arc welding method using a stitch pulse welding method.

Fig. 5 is a view showing an example of a conventional arc welding device. As an example of the use of the arc welding device X shown in Fig. 5, a welding method called a slit pulse welding method is exemplified. The slit pulse welding method is a welding method that easily suppresses the heat influence imparted to the substrate W by controlling heat input and cooling at the time of welding. When the seam welding method is used, the appearance of welding can be improved and the amount of fusion distortion can be reduced as compared with the conventional thin-plate welding (for example, refer to Patent Document 1).

The arc welding apparatus X shown in FIG. 5 includes a welding torch 91 for holding a welding wire, a robot body 92 for moving the welding torch 91 to the substrate, and a robot for controlling the operation of the robot body 92. The control device 93 and the welding power source 94 that supplies the welding voltage to the weld line 95 and the substrate W. When the fusion power source 94 supplies the welding voltage between the weld line 95 and the substrate W, an arc is generated between the tip end of the weld line 95 and the substrate W, the weld line 95 and the substrate W are melted, and the melt pool is formed on the substrate W. . This melting pool is solidified by being cooled by the shield gas sprayed from the arc welding torch 91 after the arc is stopped. When the melting pool is solidified, a weld mark is formed.

For example, in the splicing pulse welding method proposed by the patent document 2, as shown in Fig. 6, the arc is generated by energizing the alternating current pulse current while the welding torch 91 is stopped, and arcing is generated by the arc. The step (period T1) and the period of cooling and moving by applying a voltage weaker than the period T1 between the weld line 95 and the substrate W, energizing a small value of the direct current, and maintaining the arc generated (period T2) ) was repeated. By such a welding method, a part of the adjacent ones overlap, and a plurality of welding marks are continuously formed, and a scaly-shaped welded bead is formed. Further, in this case, since the arc extinguishing of the arc and the recurrence of the arc are not repeated, there is an advantage that the occurrence of sputter can be suppressed.

Further, in the method shown in Fig. 6, the abnormality determination is usually performed during welding. Specifically, when the welding current is smaller than a predetermined value or the welding voltage is larger than a predetermined value, the arc is interrupted. When the arc extinguishing is detected, the welding operation is stopped.

In the case where the detection of the interruption of such an arc is not automatically performed visually, a certain detection time is provided in order to prevent erroneous detection or the like. In other words, the time when the current is lower than the preset value or the time when the voltage value exceeds the preset value is detected, and the detection time is determined by the fact that the arc interruption is longer than the predetermined reference time. A signal for stopping the operation is transmitted to the robot controller 93 and the fusion power source 94.

For example, as shown in Fig. 6, in the case where the arc is extinguished at the time t1 and the second half of the period T1, the end of the above-described reference time is included in the period T2. In the period T2, if the arc is extinguished, at time t2, the condition that the arc is extinguished abnormally is established, and the welding is terminated. However, in the period T1 during which the arc is extinguished, there is only a certain period of welding in the second half period which is abnormal. In other words, as the entire period T1, the possibility of completion of welding in a desired state is large, and sufficient welding strength can be ensured, and the welded appearance is also relatively good. Even in such a case, there is a problem that the welding is terminated at time t2 by the abnormality determination shown in Fig. 6.

[Advanced technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 6-55268

[Patent Document 2] Japanese Patent Laid-Open No. Hei 11-267839

The present invention has been made in view of the above circumstances, and an arc welding method capable of detecting an arc interruption more appropriately is a problem.

An arc welding method according to the present invention is to alternately repetitively generate an electric arc between a substrate and a consumable electrode held by the fusion torch, a first step of transferring the droplet, and a side of the substrate and a second step of cooling the molten pool formed in the substrate and moving the fusion torch while generating an arc between the consumable electrodes; and in the first step, between the substrate and the consumable electrode When the absolute value of the voltage or the absolute value of the current flowing between the two is out of the predetermined range, the measurement of the arc extinguishing detection time is started; during the transition to the second step, the arc extinguishing detection time becomes In the case where the reference time is equal to or longer than the preset time, the fusion abnormality is determined as a feature.

In a preferred embodiment of the present invention, the reference time is set by multiplying the reference time ratio α (0% < α < 100%) by the unit time of the first step.

In a preferred embodiment of the invention, the reference time ratio α is set in a range from 40% to 60%.

In a preferred embodiment of the present invention, in the first step, the step of comparing the arc extinguishing detection time and the reference time, and the step of measuring the elapsed time of the first step are provided; only in the first When the elapsed time of the step does not reach the predetermined time, the step of comparing the arc extinguishing detection time and the reference time is performed.

In the arc welding method according to the present invention, since the measurement of the arc extinguishing detection time is performed in the first step of forming the melting pool, it is possible to avoid the abnormality in the measurement of the arc extinguishing detection time and the inability to shift to the second step. The problem of judgment. Further, by calculating the ratio of the reference time for determining the abnormality to the time for performing the first step, it is possible to satisfactorily respond to the case where the time of the first step is changed.

Other features and advantages of the present invention will become apparent from the following detailed description.

The following embodiments of the present invention will be specifically described with reference to the drawings.

Fig. 1 is a view showing a configuration of an example of a welding system suitable for carrying out the arc welding method according to the present invention. The welding system A shown in Fig. 1 includes a welding robot 1, a robot control tool 2 that controls the welding power supply device 3, and an abnormality detecting tool 4 for detecting an abnormal arc extinguishing. The welding robot 1 is configured to automatically perform arc welding on the substrate W, for example. The welding robot 1 includes a base member 11, a plurality of arms 12, a plurality of motors 13, a fusion torch 14, a wire supply device 16, and a coil liner 19.

The base member 11 is fixed to an appropriate place such as a floor. Each arm 12 is coupled to the base member 11 via a shaft.

The welding torch 14 is provided at the distal end portion of the arm portion 12a provided on the most distal end side of the welding robot 1. The fusion torch 14 is used to guide a weld wire 15 having a diameter of about 1 mm as a consumable electrode to a predetermined position in the vicinity of the substrate W. A shielding gas nozzle (not shown) for supplying a shielding gas such as Ar to the welding torch 14 is provided. The motor 13 is provided at both ends or one end of the arm 12 (partially omitted). The motor 13 is rotatably driven by the robot control tool 2. By this rotary drive, the movement of the plurality of arms 12 is controlled, and the welding torch 14 can be freely moved up and down, left and right.

In the motor 13, an encoder (not shown) is provided. The output system of this encoder is assigned to the robot control tool 2. By the output value, the current position of the fusion torch 14 is identified in the robot control tool 2.

The wire supply device 16 is provided at an upper portion of the welding robot 1. The wire supply device 16 is for welding the blow pipe 14 and feeding the weld wire 15. The wire supply device 16 includes a supply motor 161, a bobbin (not shown), and a wire bushing tool (not shown). The supply motor 161 is used as a drive source, and the wire bushing tool feeds the weld line 15 wound around the bobbin toward the fusion torch 14.

The coil pads 19 are respectively connected to the wire supply device 16 at one end and to the fusion torch 14 at the other end. The coil pad 19 is formed in a tubular shape, and inside it, the weld line 15 is inserted. The coil pad 19 guides the weld line 15 sent from the wire supply device 16 to the fusion torch 14. The melted wire 15 that is sent out protrudes from the fusion torch 14 to the outside and functions as a consumable electrode.

Fig. 2 is a view showing the internal structure of the welding system A shown in Fig. 1.

The robot control tool 2 shown in Figs. 1 and 2 controls the operation of the welding robot 1. As shown in Fig. 2, the robot control tool 2 includes a motion control circuit 21, a interface circuit 22, and a teach pendant TP.

The motion control circuit 21 includes a microcomputer and a memory (not shown). In this memory, the various programs in which the welding robot 1 is operated are memorized. Further, the motion control circuit 21 sets a robot moving speed VR which will be described later. The motion control circuit 21 provides an operation control signal Mc to the welding robot 1 based on the above-described work program, coordinate information from the encoder, and the robot moving speed VR. By the operation control signal Mc, the motors 13 are rotatably driven, and the welding torch 14 can be moved to a predetermined welding start position of the substrate W, or can be moved in the planar direction of the substrate W.

The teaching mode TP is connected to the motion control circuit 21. The teaching mode TP is used to set various actions by the user.

The interface circuit 22 is for interacting with the fusion power supply device 3 for various signals. In terms of the interface circuit 22, the current control signal Is, the current start signal On, the output start signal On, and the supply speed setting signal Ws are transmitted from the operation control circuit 21. In terms of the current setting signal Is, for example, a pulse output time set by the teaching mode TP is included. The interface circuit 22 transmits the current setting signal Is to the abnormality detecting tool 4.

The welding power supply device 3 is a device for applying a welding voltage Vw between the welding wire 15 and the substrate W to flow the welding current Iw, and is a device for supplying the welding wire 15. As shown in Fig. 2, the welding power supply device 3 includes an output control circuit 31, a current detecting circuit 32, a supply control circuit 34, a interface circuit 35, and a voltage detecting circuit 36.

The interface circuit 35 is for interacting with the robot control tool 2 for various signals. Specifically, in the interface circuit 35, the current setting signal Is, the output start signal On, and the supply speed setting signal Ws are transmitted from the interface circuit 22.

The output control circuit 31 has an inverter control circuit composed of a plurality of transistor elements. The output control circuit 31 controls the precision welding current waveform with a high-speed response from a commercial power source (for example, three-phase 200V) input from the outside.

The output of the output control circuit 31 is connected at one end to the fusion torch 14 and at the other end to the substrate W. The output control circuit 31 applies a welding voltage Vw between the weld line 15 and the substrate W via a contact pipe provided at the tip end of the fusion torch 14, and flows the welding current Iw. An example of a state change of the welding current Iw is shown in Fig. 4(c). Thereby, the arc a is generated between the tip end of the weld line 15 and the substrate W. By the heat thus extracted by the arc a, the weld line 15 and the substrate W are melted. Further, it is applied to the substrate W and welded.

The output control circuit 31 transmits the current setting signal Is and the output start signal On from the operation control circuit 21 via the interface circuits 35 and 22.

The current detecting circuit 32 is for detecting the welding current Iw flowing to the weld line 15. The current detecting circuit 32 outputs a current detecting signal Id corresponding to the welding current Iw to the output control circuit 31 and the operation control circuit 21. Further, the current detection signal Id is transmitted to the abnormality detecting tool 4 via the interface circuit 35.

The voltage detecting circuit 36 is for detecting a welding voltage Vw which is a voltage of the output terminal of the output control circuit 31. The voltage detecting circuit 36 outputs a voltage detection signal Vd corresponding to the welding voltage Vw to the output control circuit 31.

The supply control circuit 34 outputs a supply control signal Fc for supplying the weld line 15 to the supply motor 161. The supply control signal Fc is a signal indicating the supply speed Fv of the weld line 15. Further, in the supply control circuit 34, the output start signal On from the operation control circuit 21 and the supply speed control signal Ws are transmitted via the interface circuits 35 and 22.

The abnormality detecting means 4 includes an arc stop time measuring means 41, an abnormality determining means 42, and a interface circuit 43 as means for detecting a current extinguishing abnormality from the stop time of the current. The interface circuit 43 is for interacting with the robot control tool 2 and the fusion power supply device 3, receives the current setting signal Is from the interface circuit 22, and receives the current detection signal Id from the interface circuit 35.

The arc stop time measuring device 41 includes, for example, a microcomputer and a memory, and receives the current detection signal Id via the interface circuit 43 to monitor the welding current Iw, and measures the arc extinguishing detection time Ta according to a method described later. The arc stop time measuring device 41 performs a process of increasing the arc extinguishing detection time Ta by one when the welding current Iw is zero for a certain period of time. Further, the arc stop time measuring device 41 transmits the arc extinguishing detection time Ta to the abnormality determining device 42.

The abnormality determining device 42 is provided with, for example, a microcomputer and a memory, and receives the current setting signal Is via the interface circuit 43. The abnormality determining means 42 performs setting of the reference time Tstp for determining the arc extinguishing, and compares the reference time Tstp with the arc extinguishing detecting time Tao. Further, the abnormality determining device 42 may be integrated with the arc stop time measuring device 41. When the arc extinguishing detection time Tao exceeds the reference time Tstp, the abnormality determining means 42 transmits the arc abnormality signal Ea of the transmission arc interruption to the interface circuit 43. The interface circuit 43 transmits the arc abnormality signal Ea to the operation control circuit 21 via the interface circuit 22.

Next, an arc welding method in the present invention will be described. This arc welding method is performed using the welding system A.

Fig. 3 is a flow chart showing a method of splice pulse welding using the welding system A. In addition, FIG. 4 is a view showing a state of change in the welding condition value of the welding operation in the predetermined welding system A. Specifically, the fourth (a) diagram shows the change state of the robot moving speed VR, the fourth (b) diagram shows the change state of the supply speed Fv of the weld line 15, and the fourth (c) figure shows the welding current Iw. The state of change. The robot moving speed VR is a moving speed of the welding torch 14 in the direction in which the predetermined welding is performed in the planar direction of the substrate W. Further, the welding voltage Vw is set so that the necessary voltage is appropriately set in order to flow the welding current Iw.

In the slit pulse welding method, a relatively strong arc a, a first step in which the droplet is transferred, and a relatively weak arc a are generated while cooling the molten pool formed on the substrate W, and The second step of the movement of the fusion torch 14 is alternately repeated. In the present embodiment, as shown in FIG. 4(c), in the first step (T1), the alternating current pulse current flows as the welding current Iw, and in the second step (T2), the direct current is used as the welding current Iw. The circulation, the unit time of the first step (T1), is the pulse output time set by the teaching mode TP.

First, by the welding start signal St (refer to FIG. 2) from the teaching mode TP, the transition welding start processing is performed. In the welding start processing, the operation control circuit 21 outputs an output start signal On to the output control circuit 31 and the supply control circuit 34. The output control circuit 31 applies a welding voltage Vw between the weld line 15 and the substrate W. Thereby, the arc a is ignited.

Next, the pulse output time Tpls and the reference time Tstp are set (S1). In the present embodiment, the setting is taken as the start of the first step (T1). The pulse output time Tpls and the reference time Tstp are set as values indicating the number of sampling times Ts corresponding to the primary pulse of the welding current Iw in the first step (T1). Specifically, the pulse output time Tpls is set by dividing the pulse output time set by the teaching mode TP by the integer part of the value obtained by dividing the sampling time Ts. Moreover, these processes are performed, for example, in the operation control circuit 21. The pulse output time Tpls set here is included in the current setting signal Is, and is transmitted to the abnormality determining device 42. The abnormality determining means 42 multiplies the pulse output time Tpls by the reference time ratio α, and sets the integer portion thereof as the reference time Tstp. In the present embodiment, the reference time ratio α is in the range of 40% to 60%, and can be appropriately set and changed, for example, by the teaching mode TP.

Next, the arc extinguishing detection time Tao is set to 0, and the pulse output elapsed time Tp is set to 0 (S2). The arc extinguishing detection time Tao is a value managed in the arc stop time measuring device 41. The pulse output is a value managed by the operation control circuit 21 after the elapse of time Tp.

After the end of these settings, the pulse output is started (S3). After that, the processing of the sampling time Ts is waited for (S4), and the following processing is performed.

The arc stop time measuring device 41 monitors the current detection signal Id, and determines whether or not the welding current Iw is 0 during the sampling time Ts (S5). Further, the welding current Iw cannot be accurately zero, and it is also possible to determine whether or not the absolute value of the welding current Iw is smaller than a predetermined value.

In the case where the welding current Iw is not zero during the sampling time Ts (S5=no), the arc stop time measuring device 41 sets the value of the arc extinguishing detection time Tao to 0 (S6).

In the case of the sampling time Ts, when the welding current Iw is 0 (S5=yes), the arc stop time measuring device 41 performs a process of adding 1 to the value of the arc extinguishing detection time Tao (S7). Further, the abnormality determining device 42 determines whether or not the value of the arc extinguishing detection time Ta is equal to or greater than the reference time Tstp (S8). When the value of the arc extinguishing detection time Tao is equal to or greater than the reference time Tstp (S8=yes), the abnormality determining device 42 transmits the arc abnormality signal Ea to the operation control circuit 21 (S9). The operation control circuit 21 receives the arc abnormality signal Ea and performs a process of stopping the operation of the welding robot 1 to terminate the welding operation.

When the value of the arc extinguishing detection time Tao is 0 (S6) and the value of the arc extinguishing detection time Tao does not exceed the reference time Tstp (S8=no), the operation control circuit 21 performs the value of the pulse output elapsed time Tp. The process of adding 1 (S10). Thereafter, the operation control circuit 21 determines whether or not the value of the pulse output elapsed time Tp is equal to or greater than the pulse output time Tpls (S11).

When the value of the pulse output elapsed time Tp is equal to or greater than the pulse output time Tpls (S11=yes), it is determined whether or not the welding is finished (S12). The timing at which the welding is completed is determined, for example, from the teaching mode TP. When the instruction to terminate the welding is performed (S12=yes), the operation control circuit 21 performs a process of stopping the operation of the welding robot 1, and the welding operation is completed. In the case where the end of the welding is not performed (S12 = no), the process proceeds to the second step (T2) (S13). Specifically, as the welding current Iw, a direct current is caused to flow, and the welding torch 14 is moved to the next welding position. During this period, the molten pool formed in the substrate W in the first step (T1) is cooled. After the second step (T2) is finished, it returns to the first step (S1) of the first step (T1).

When the value of the pulse output elapsed time Tp has not reached the pulse output time Tpls (S11=no), the pulse current output is continued, and the process returns to the sampling time standby step (S4).

In the right part of Fig. 4, the state of change of each welding condition value in the case where the arc is extinguished is shown. According to Fig. 4, the pulse output starts at time t1, and the arc extinguishes at time t2. The time t3 is the time at which the value of the arc extinguishing detection time Tao is equal to the reference time Tstp. According to the above-described arc welding method, the abnormality determining device 42 transmits the arc abnormality signal Ea to the operation control circuit 21 at time t3 (S9). When the operation control circuit 21 receives the arc abnormality signal Ea, the process of stopping the operation of the welding robot 1 is performed. By this processing, the line supply speed Fv at the time t3 becomes zero. Further, in the case where the arc is extinguished, the welding voltage Vw becomes the maximum load-free voltage value, but the welding voltage Vw at the time t3 also becomes zero.

According to such an arc welding method, when the value of the arc extinguishing detection time Ta is equal to or greater than the reference time Tstp in the middle of the first step (T1), the welding operation is stopped, and the value of the arc extinguishing detection time Tao does not reach the reference time Tstp. In the case of the situation, the welding operation is continued. Further, the reference time Tstp is determined by multiplying the pulse output time Tpls by the reference time ratio α, and usually the time during which the arc is extinguished reaches 40% to 60% of the predetermined time for performing the first step (T1). In the case, an abnormality is detected. Therefore, according to such an arc welding method, in a predetermined time period in which the first step (T1) is carried out, the time of a certain ratio portion is surely performed in the state in which the arc is generated, and the welding bead can be prevented from being largely lost.

According to the above-described arc welding method, the reference time Tstp is a value corresponding to 40% to 60% of the set pulse output time Tpls. Therefore, in the initial stage of the first step (T1), when the arc extinguishing has started, the arc abnormality signal Ea is transmitted and the welding operation is interrupted before the end of the first step (T1). Therefore, it is possible to prevent the fusion bonding bead which is transferred to the next welding position in an insufficiently formed state of the molten pool and which is not good in appearance. Further, after the problem is solved, the welding operation is resumed without moving the welding position, and the welding operation can be smoothly performed.

According to the arc welding method of the present embodiment, just before the end of the first step (T1) and the arc extinction starts, before the arc abnormality signal Ea is transmitted, the value of the pulse output elapsed time Tp becomes the pulse output time Tpls ( S11=yes) or above. Therefore, the welding operation is not interrupted, and the second step (T2) is started. Just before the end of the first step (T1), in the case where the arc is extinguished, the formation of the molten pool itself is sufficiently performed to some extent before the arc extinguishing is caused, and the fusion failure is not considered. Therefore, unnecessary welding stop can be avoided. Similarly, before the arc extinguishing detection time Tao exceeds the reference time Tstp, in the case where the arc a starts again, there is no need to stop the welding. In this case, in the present embodiment, unnecessary welding stop can be avoided.

In the above embodiment, at the start of the first step (T1), the pulse output time Tpls and the reference time Tstp are set (S1), but only at the start of the fusion and the pulse output time set by the teaching mode TP. When the reference time ratio α is changed, it is also possible to perform these settings.

Further, in the present embodiment, when the operation control circuit 21 receives the arc abnormality signal Ea (S9), the process of stopping the welding operation is performed. However, the welding robot 1 is not stopped, and only the user may be warned. In this case, the operation control circuit 21 performs a process of causing the arc a to be generated again.

Further, it is also possible to monitor the value of the direct current in the second step (T2) as needed. In this case, the arc stop time measuring means 41 manages the DC arc extinguishing detection time in addition to the arc extinguishing detection time Ta. When the DC arc extinguishing detection time exceeds a predetermined time, the arc stop time measuring device 41 generates a signal that must be transmitted again for the operation control circuit 21 and the transmission arc a. Based on this signal, the operation control circuit 21 performs the re-generation process of the arc a when shifting from the second step (T2) to the first step (T1).

The scope of the present invention is not limited to the above embodiments. The specific configuration of each part of the welding system used in the present invention is variously designed and changed, and the details of the arc welding method according to the present invention can be appropriately changed. For example, in the above embodiment, the arc stop time measuring device 41 and the abnormality determining device 42 are provided outside the motion control circuit 21, but the motion control circuit 21 may also serve as the arc stop time measuring device 41 and the abnormality determining device 42. .

For example, in the above-described embodiment, the arc stop time measuring device 41 determines whether or not the arc extinguishing is generated by monitoring the current detecting signal Id, but may monitor the welding voltage Vw by receiving the voltage detecting signal Vd. In the case where the arc is extinguished, the welding voltage Vw becomes the maximum value of the no-load voltage. Here, in the case where the welding voltage Vw is higher than a value set in advance during the sampling time Ts, by performing the process of adding 1 to the arc extinguishing detection time Tao (S7), the welding current Iw can be monitored and monitored. The same arc extinguishing decision is made.

Further, in the above embodiment, the welding current Iw in the first step (T1) is an alternating current pulse current, but it may be a direct current pulse current.

A. . . Fusion system

1. . . Welding robot

11. . . Base member

12. . . arm

12a. . . Wrist

13. . . motor

14. . . Fusion blowpipe

15. . . Weld line (consumption electrode)

16. . . Line supply device

161. . . Supply motor

2. . . Robot control tool

twenty one. . . Motion control circuit

twenty two. . . Interface circuit

3. . . Fusion power supply unit

31. . . Output control circuit

32. . . Current detection circuit

34. . . Supply control circuit

35. . . Interface circuit

36. . . Voltage detection circuit

4. . . Anomaly detection tool

41. . . Arc stop time measuring device

42. . . Abnormality determination device

43. . . Interface circuit

Ea. . . Arc anomaly signal

Fc. . . Supply control signal

Fv. . . Supply speed

Is. . . Current setting signal

Iw. . . Splicing current

Mc. . . Motion control signal

On. . . Output start signal

T1. . . First step

T2. . . Second step

TP. . . Teaching mode

Tp. . . Pulse output elapsed time

Tpls. . . Pulse output time

Ts. . . sampling time

Tao. . . Arc extinguishing detection time

Tstp. . . Base time

VR. . . Robot movement speed

Vw. . . Splicing voltage

W. . . Substrate

Ws. . . Supply speed setting signal

α. . . Base time ratio

1 is a view showing a configuration of an example of a welding system for performing an arc welding method according to the present invention;

Fig. 2 is a view showing the internal structure of the welding system shown in Fig. 1;

Figure 3 is a flow chart showing an arc welding method relating to the present invention;

Fig. 4 is a view showing a state of change of a welding condition value in the arc welding method of the present invention;

Figure 5 is a diagram showing the configuration of an example of a conventional fusion splicing system;

Fig. 6 is a view showing the detection abnormality caused in the conventional slit pulse welding method.

Claims (4)

An arc welding method of alternately repeating a first step of generating an arc between a substrate and a consumable electrode held by the fusion torch, a transfer of the droplet, and a side between the substrate and the consumable electrode a second step of generating an arc, cooling the molten pool formed on the substrate, and moving the fusion torch, in the first step, an absolute value of a voltage between the substrate and the consumable electrode or When the absolute value of the current flowing between the two is out of the predetermined range, the measurement of the arc extinguishing detection time is started; and the arc extinguishing detection time is set to a predetermined standard during the transition to the second step. In the case of time or longer, the determination of the welding abnormality is characterized. The arc welding method according to claim 1, wherein the reference time is set by multiplying the unit time of the first step by the reference time ratio α, and α is 0% < α < 100%. . The arc welding method according to claim 2, wherein the reference time ratio α is set in a range from 40% to 60%. The arc welding method according to claim 1, wherein the step of comparing the arc extinguishing detection time and the reference time and the measuring the elapsed time of the first step are performed in the first step. It is provided that the step of comparing the arc extinguishing detection time and the reference time is performed only when the elapsed time of the first step does not reach the preset time.