JP2005271042A - Consumable electrode gas shielded arc welding method by constant current property - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain satisfactory welding quality, in an consumable electrode gas shielded arc welding using a welding power source having constant current properties, by suppressing the variation of arc length caused by disturbance such as variation in feeding rates and variation in the distance between a power feeding tip and a base material. <P>SOLUTION: In the consumable electrode gas shielded arc welding method by constant current properties where welding wire is fed at a beforehand decided velocity, and further, welding current Iw1 beforehand decided in accordance with the fixed current properties CC1 of a welding power source is energized to an arc, so as to perform welding, a welding voltage between the base metal and the welding wire is detected, the detected value of the welding voltage is subjected to moving averaging to calculate the moving average value of the welding voltage, and the welding current value Iw2 in accordance with the fixed current properties CC2 is changed in such a manner that the detected value of the welding voltage is made almost equal to the moving average value of the welding voltage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a consumable electrode gas shielded arc welding method with constant current characteristics for suppressing fluctuations in arc length due to disturbance in consumable electrode gas shielded arc welding with constant current characteristics.

[Prior art 1]
FIG. 7 is a diagram showing the relationship between the melting characteristic L1 of the welding wire and the external characteristic CP1 of the welding power source in aluminum MIG welding. In the figure, the horizontal axis indicates the welding current Iw energizing the arc, and the vertical axis indicates the welding voltage Vw between the welding wire and the base material. The melting characteristic L1 is obtained by measuring changes in the welding current Iw and the arc length La when the welding wire feeding speed is set to a predetermined constant value and the welding voltage Vw is changed. At the point Q1, the arc length La is about 2 mm, and at each point on the melting characteristic L1 lower than this, the droplet transfer form becomes a short-circuit transfer form. At point Q2, the arc length La is about 6 mm, and at each point on the melting characteristic L1 above this point, the droplet transfer form becomes a spray transfer form. At each point between points Q1 and Q2, the droplet transfer form is a mesospray transfer form. In this mesospray transfer mode, the droplets are transferred to the spray while a short time of 1 ms or less occurs. In consideration of welding quality such as spatter, bead appearance, blow hole, etc., the range of arc length La that is practically used is about 2 to 5 mm. Therefore, in the range of the arc length La used practically, the droplet transfer form is a mesospray transfer form.

  By the way, the arc length La is determined by the balance between the welding wire feeding speed and the melting speed. The melting rate depends on the welding current Iw. Since the melting characteristic L1 is when the feeding speed is constant, the value of the welding current Iw is determined so that the melting speed and the feeding speed are equal for each arc length. In the melting characteristic L1, the welding current value at the point Q2 with an arc length La = 6 mm is larger than the welding current value at the point Q1 with an arc length La = 2 mm. , The specific melting amount) becomes smaller. That is, in the mesospray transfer mode, the specific melting amount decreases in inverse proportion to the arc length La. For this reason, when the welding current Iw is a constant value (when using a welding power source having a constant current characteristic), the arc length La becomes transient due to disturbances such as fluctuations in the feeding speed and fluctuations in the distance between the feeding tip and the base material. If the length is longer, the specific melting amount becomes smaller and the melting speed becomes slower, so that the arc length La is controlled in the direction of shortening. On the other hand, when the arc length La is shortened due to a disturbance, the specific melting amount is increased and the melting rate is increased, so that the arc length La is controlled to become longer. This action of restoring the variation in arc length is called the arc-specific self-control action.

  Generally, a welding power source having a constant voltage characteristic CP1 is used for aluminum MIG welding. In this case, the melting characteristic L1 is determined when the feeding speed is set, and the constant voltage characteristic CP1 is determined when the welding voltage Vw is set. The intersection P1 of these two characteristics is the operating point. The arc length La at point P1 is set to 4 mm. In the steady arc state, the operating point stops at point P1, and the arc length La is maintained at 4 mm. In this state, when the arc length La becomes transiently long due to disturbance, the operating point moves transiently to the point P2 on the constant voltage characteristic CP1. As a result, the welding current value Iw is reduced and the melting rate is decreased, so that the arc length La is restored in the direction of shortening. This action is called a self-control action based on external characteristics to distinguish it from the arc-specific self-control action. Usually, in order to obtain a good welding quality by suppressing the fluctuation of the arc length La due to disturbance, the self-control action inherent to the arc has a problem in responsiveness, so the self-control action based on external characteristics is used. For this reason, a welding power source having constant voltage characteristics is used in aluminum MIG welding.

  When the welding conditions such as the material of the aluminum wire, the diameter, the type of shield gas, etc. are determined and the feeding speed is set, the melting characteristic L1 is determined. For this purpose, the constant voltage characteristic CP1 may be set so that the desired arc length La is obtained. However, aluminum MIG welding has a property that the melting characteristic L1 changes depending on the state of the oxide film of the base material. FIG. 8 is a diagram showing melting characteristics L1 and L2 when the state of the oxide film of the base material changes. Melting characteristic L1 is the same as melting characteristic L1 of FIG. In MIG welding, welding is performed while removing (cleaning action) the base oxide film with an arc. The cleaning state of the oxide film is greatly affected by fluctuations in the condition of the surface of the base material, the temperature of the base material, the shielding state of the shielding gas, and the like. In addition, the cleaning state of the oxide film changes every time during welding.

  When the cleaning state of the oxide film changes, the melting characteristics change from L1 to L2. This is because the arc shape changes due to the change in the cleaning state of the oxide film, and the melting rate changes. In order to set the arc length La = 4 mm to a desired value when the melting characteristic is L1, the constant voltage characteristic is set to CP1 so that the operating point becomes the P1 point. In order to maintain the arc length La at 5 mm when the melting characteristic changes to L2 in this state, it is necessary to move the operating point to the point P3. Therefore, it is necessary to change the setting of the constant voltage characteristic from CP1 to CP2. That is, in aluminum MIG welding, the setting of the constant voltage characteristic has to be corrected in order to maintain the arc length at a desired value every time the cleaning state of the oxide film changes. As described above, since the cleaning state of the oxide film also changes during welding, it is necessary to change the setting of the constant voltage characteristics during welding. For this reason, it has been practiced in the field that the welding operator manually adjusts the constant voltage characteristics while visually confirming the variation in the arc length due to the variation in the cleaning state of the oxide film. However, this method has a problem that automation is difficult and the arc length cannot be accurately maintained at a desired value.

[Prior Art 2]
Prior art 2 for solving the above-described problem will be described below. FIG. 9 is a melting characteristic L3 drawn by changing the vertical axis from the welding voltage Vw to the arc length La for the melting characteristics L1 and L2 described above with reference to FIG. The melting characteristic L3 in the figure does not change even when the cleaning state of the oxide film changes. This is because the principle that the melting rate is determined by the welding current Iw and the arc length is determined by the melting rate does not change even if the cleaning state of the oxide film changes. In FIG. 8 described above, since the arc length is controlled by the welding voltage Vw, the value of the welding voltage Vw for the same arc length changes when the cleaning state of the oxide film changes and the arc shape changes. A problem occurs. On the other hand, since the arc length La is controlled by the welding current Iw in the figure, it is not affected by fluctuations in the cleaning state of the oxide film.

  In the figure, in order to set the desired value of the arc length La = 4 mm, the external characteristic of the welding power source may be the constant current characteristic CC1 and the operating point may be P4. As a result, even if the cleaning state of the oxide film changes, the operating point P4 does not change, so the arc length La remains at the desired value of 4 mm. Therefore, the above-described problem of the conventional technique 1 is solved (for example, see Patent Document 1).

Japanese Patent No. 2993174

  In the prior art 2 described above, the restoring force when the arc length La changes due to disturbances such as fluctuations in the feeding speed and fluctuations in the distance between the power supply tip and the base material is the above-described self-control action inherent to the arc. That is, in FIG. 9, when the arc length La becomes transiently long due to a disturbance, the operating point moves to P5. Even at this operating point P5, since the welding current value Iw is a constant value, the self-control action by the external characteristics does not work as in the prior art 1. In this case, as described above, since the arc length La becomes longer and the specific melting amount becomes smaller, the melting rate at the same welding current value Iw becomes slower and the arc length La is controlled to become shorter. However, this arc-specific self-control action has a problem that the transient response to restore the arc length is poor. According to the self-control action by the external characteristic in the prior art 1, the transient response for restoring the arc length is about 20 ms. On the other hand, the transient response due to the arc-specific self-control action is about 70 ms, which is several times slower. As a result, the fluctuation range of the arc length La due to disturbance is increased, and the welding quality may be deteriorated. For this reason, it has been practically impossible to use a welding power source having constant current characteristics for MIG welding.

  Therefore, the present invention provides a consumable electrode gas shielded arc welding method with constant current characteristics excellent in transient response that can reduce fluctuations in arc length due to disturbance.

In order to solve the above-mentioned problem, the first invention is a constant current that feeds a welding wire at a predetermined speed and conducts welding by applying a predetermined welding current to the arc according to a constant current characteristic of a welding power source. In the consumable electrode gas shield arc welding method by characteristics,
The welding voltage between the base metal and the welding wire is detected, the welding voltage detection value is moving averaged to calculate a welding voltage moving average value, and the welding voltage detection value is substantially equal to the welding voltage moving average value. The consumable electrode gas shield arc welding method with constant current characteristics, wherein the welding current value according to the constant current characteristics is changed.

  Further, the second invention is consumable electrode pulse arc welding in which the consumable electrode gas shielded arc welding repeats energization of a peak current during a peak period and energization of a base current during a base period as a pulse period, and the welding current value Is a welding current average value for each pulse period, the welding voltage value is a welding voltage average value for each pulse period, and at least one or more of the peak period, the peak current, the base period, or the base current The consumable electrode gas shielded arc welding method with constant current characteristics according to the first aspect of the present invention is characterized in that the welding current average value for each pulse period is changed by changing.

  According to the first aspect of the present invention, consumable electrode gas shielded arc welding is performed with a constant current characteristic, and the constant current characteristic is changed so that the welding voltage Vw and the moving average value Vra are substantially equal to each other. Control action can be activated. For this reason, the fluctuation of the arc length due to the disturbance and the fluctuation of the cleaning state of the oxide film can be quickly suppressed, and good welding quality can be obtained. As a result, consumable electrode gas shielded arc welding with constant current characteristics has become practical.

  According to the second aspect, the same effect as described above can be obtained in consumable electrode pulse arc welding, and the welding quality in pulse arc welding can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
Embodiment 1 of the present invention detects a welding voltage, calculates a welding voltage moving average value by moving and averaging the welding voltage detection values, and the welding voltage detection value is substantially equal to the welding voltage moving average value. This is a consumable electrode gas shielded arc welding method with constant current characteristics in which the welding current value with constant current characteristics is changed to be equal.

  FIG. 1 is a relationship diagram between a melting characteristic L3 and constant current characteristics CC1 and CC2 for explaining an operation principle of a consumable electrode gas shielded arc welding method using constant current characteristics according to Embodiment 1 of the present invention. In the figure, the horizontal axis indicates the welding current Iw, and the vertical axis indicates the arc length La. The melting characteristic L3 and the constant current characteristic CC1 in the figure are the same as those in FIG. Hereinafter, a description will be given with reference to FIG.

  First, a steady arc state in which the above-described disturbance has not occurred and the oxide film cleaning state has not changed will be considered. When the feeding speed is set, the melting characteristic becomes L3. The constant current characteristic is set to CC1 so that the arc length La becomes a desired value of 4 mm. The operating point is the intersection P4 of both characteristics. Since the operating point is fixed at the point P4 in the steady arc state, the arc length La is maintained at a desired value.

  When a disturbance occurs in this steady arc state and the arc length La becomes transiently long, the operating point moves from P4 to P5. In the present invention, the welding current value Iw based on the constant current characteristic is changed according to the voltage error amplification value ΔV = G · (Vra−Vw) between the welding voltage Vw and the welding voltage moving average value Vra. Here, G is an amplification factor. That is, Iw2 = Iw1 + ΔV. The welding current Iw1 is a current value of the constant current characteristic CC1. When the arc length La becomes longer due to disturbance, the welding voltage Vw becomes larger than the welding voltage moving average value Vra, and the voltage error amplification value ΔV <0. As a result, Iw2 <Iw1, and the constant current characteristic changes to CC2. In response to this, the operating point moves from P5 to P6. Since the welding current decreases when the operating point becomes P6, the melting rate is slowed and the arc length La is controlled to be shortened. That is, the fluctuation of the arc length La due to the disturbance is detected by the voltage error amplification value ΔV, and the constant current characteristic is changed to make the self-control action by the external characteristic work. As described above, the self-control action based on the external characteristics has better transient response of the arc length control and the fluctuation range is smaller than the self-control action inherent to the arc.

  Next, when the cleaning state of the oxide film varies in the steady arc state, the welding voltage Vw changes. However, the fluctuation rate of the oxide film cleaning state is slower than the fluctuation rate due to the above disturbance. For example, the fluctuation speed due to the disturbance is about several ms to several tens of ms, while the fluctuation speed of the oxide film cleaning state is about several tens to several hundred ms. Therefore, the moving average period for calculating the welding voltage moving average value Vra is set to be longer than the fluctuation speed of the disturbance and shorter than the fluctuation speed of the oxide film cleaning state. As a result, when a gradual change in the cleaning state of the oxide film occurs, Vw≈Vra, and the constant current characteristic remains CC1. For this reason, even if the cleaning state of the oxide film fluctuates, the arc length La remains at a desired value. On the other hand, when a disturbance occurs, Va ≠ Vra as described above, and the constant current characteristic changes transiently from CC1 to CC2 and the like, and the self-control action by the external characteristic works. When returning to the steady arc state, the constant current characteristic returns to CC1.

  FIG. 2 is a block diagram of a welding power source for carrying out the consumable electrode gas shielded arc welding method with constant current characteristics according to the first embodiment described above. The power supply main circuit MC receives a commercial AC power supply (3-phase 200 V or the like) as an input, performs output control by inverter control or the like according to a current error amplification signal Ei described later, and outputs a welding current Iw and a welding voltage Vw. The welding wire 1 is fed through the welding torch 4 by the rotation of the feeding roll 5 of the wire feeding device, and an arc 3 is generated between the welding wire 1 and the base material 2.

  The welding voltage detection circuit VD detects the welding voltage Vw and outputs a welding voltage detection signal Vd. The welding voltage moving average value calculation circuit VRA averages the welding voltage detection signal Vd and outputs a welding voltage moving average value signal Vra. The voltage error amplification circuit EV amplifies the error between the welding voltage moving average value signal Vra and the welding voltage detection signal Vd and outputs a voltage error amplification signal ΔV = G · (Vra−Vd). G is a predetermined amplification factor. The current setting circuit IS outputs a predetermined current setting signal Is. The adder circuit AD adds the current setting signal Is and the voltage error amplification signal ΔV, and outputs a current control setting signal Isc = Is + ΔV. The current detection circuit ID detects the welding current Iw and outputs a welding current detection signal Id. The current error amplification circuit EI amplifies an error between the current control setting signal Isc and the welding current detection signal Id and outputs a current error amplification signal Ei. By this circuit, a constant current characteristic determined by the current control setting signal Isc is formed. In the steady arc state in which the voltage error amplification signal ΔV = 0, Isc = Is, so that a constant current characteristic determined by the current setting signal Is is formed. For example, in FIG. 1 described above, when Is = Iw1, the constant current characteristic CC1 is formed. Similarly, when the voltage error amplification signal ΔV> 0 and Isc = Iw2 due to disturbance, a constant current characteristic CC2 is formed.

[Embodiment 2]
The second embodiment of the present invention is a case where consumable electrode pulse arc welding is used as the consumable electrode gas shield arc welding in the first embodiment. FIG. 3 shows current / voltage waveforms of pulse arc welding. FIG. 4A shows the time change of the welding current instantaneous value iw, and FIG. 4B shows the time change of the welding voltage instantaneous value vw. During the peak period Tp from time t1 to t2, as shown in FIG. 4A, a large current peak current Ip is applied to transfer the droplet, and welding is performed as shown in FIG. A peak voltage Vp is applied between the wire and the base material. During the base period Tb from time t2 to t3, as shown in FIG. 6A, the base current Ib having a small current value is energized so as not to melt the welding wire, and as shown in FIG. A base voltage Vb is applied between the wire and the base material. A pulse period Tf is formed from the peak period Tp and the base period Tb. In the pulse arc welding, so-called 1-pulse 1-droplet transfer in which one droplet moves to the base material every pulse period Tf. Therefore, the arc length La changes every pulse period Tf. Therefore, as the welding current Iw and the welding voltage Vw in the first embodiment, the welding current average value Iwa for each pulse period Tf and the welding voltage average value Vwa for each pulse period Tf must be used in the second embodiment. There is. That is, in the second embodiment, the constant current characteristic is formed so that the above-described pulse period welding current average value Iwa becomes a constant value. The welding voltage moving average value Vra is calculated by moving average the above-mentioned pulse period welding voltage average value Vwa. Therefore, the voltage error amplification value ΔV = G · (Vra−Vwa). In FIG. 5A, when the peak period Tp, peak current Ip, base period Tb, and base current Ib are set, the pulse cycle welding current average value Iwa is set to a predetermined value. Therefore, in order to change the pulse period welding current average value Iwa, it is only necessary to change at least one of the peak period Tp, the peak current Ip, the base period Tb, or the base current Ib. Other than the above, the second embodiment is the same as the first embodiment.

  FIG. 4 is a block diagram of a welding power source for carrying out the consumable electrode gas shield arc welding method with constant current characteristics according to Embodiment 2 of the present invention. In the figure, the same blocks as those in FIG. 2 described above are denoted by the same reference numerals, and description thereof is omitted. Hereinafter, blocks indicated by dotted lines different from those in FIG. 2 will be described.

  The pulse cycle welding voltage average value calculation circuit VWA calculates an average value of the welding voltage detection signal Vd that detects the welding voltage instantaneous value vw for each pulse cycle Tf, and outputs a pulse cycle welding voltage average value signal Vwa. The welding voltage moving average value calculation circuit VRA moves and averages the pulse period welding voltage average value signal Vwa and outputs a welding voltage moving average value signal Vra. The voltage error amplification circuit EV amplifies the error between the welding voltage moving average value signal Vra and the pulse period welding voltage average value signal Vwa, and outputs a voltage error amplification signal ΔV = G · (Vra−Vwa). G is a predetermined amplification factor.

  The base period setting circuit TBS outputs a predetermined base period setting signal Tbs. The subtraction circuit SB subtracts the voltage error amplification signal ΔV from the base period setting signal Tbs, and outputs a base period control setting signal Tbsc = Tbs−ΔV. The peak period setting circuit TPS outputs a predetermined peak period setting signal Tps. The timer circuit TM becomes High level during the period determined by the peak period setting signal Tps, and becomes Low level during the period determined by the subsequent base period control setting signal Tbsc. Thereafter, the timer circuit Tm repeats this operation. Output. That is, when the timer signal Tm is at the high level, the peak period is set, and when the timer signal Tm is at the low level, the base period is set. The peak current setting circuit IPS outputs a predetermined peak current setting signal Ips. The base current setting circuit IBS outputs a predetermined base current setting signal Ibs. The switching circuit SW switches to the a side when the timer signal Tm is at the high level and outputs the peak current setting signal Ips as the current control setting signal Isc, and switches to the b side when the timer signal Tm is at the low level. The base current setting signal Ibs is output as the current control setting signal Isc. The welding current instantaneous value iw described above with reference to FIG. 3 corresponding to the current control setting signal Isc is energized.

  In the figure, since the voltage error amplification signal ΔV = 0 when in the steady arc state, Tbsc = Tbs. Therefore, a current determined by the peak current setting signal Ips is energized during the period determined by the peak period setting signal Tps, and a current determined by the base current setting signal Ibs is energized during the period determined by the base period setting signal Tbs. The pulse period welding current average value Iwa in this state is Iw1 in FIG.

  When a disturbance occurs in the steady arc state and the arc length La becomes transiently long, the voltage error amplification signal ΔV> 0. Therefore, Tbsc <Tbs, and the base period is shorter than the steady arc state. As a result, the pulse period welding current average value Iwa becomes small and becomes Iw2 in FIG. As a result, a self-control action due to the external characteristics is exerted to suppress fluctuations in the arc length La.

  In the above description, the base period Tb is varied to change the pulse period welding current average value Iwa. In addition, when the peak period Tp is varied, Tp = Tps + ΔV may be set. Similarly, when the base current Ib is varied, Ib = Ibs + ΔV. Further, when the peak current Ip is varied, Ip = Ips + ΔV may be set. Moreover, although the above demonstrated aluminum MIG welding, it is applicable also to MIG welding, such as magnesium in which an oxide film is formed in a base material.

[effect]
FIG. 5 is a diagram showing a method for measuring the transient response at the time of changing the arc length in order to explain the effect of the present invention. This is a case where an aluminum alloy material having a diameter of 1.2 mm is used for the welding wire, and pulse MIG welding is performed at an average welding current of 100 A, an average welding voltage of 18 V, and a welding speed of 80 cm / min. At time t1, the arc length is set to 2 mm, and at time t2, the distance between the feed tip and the base material becomes longer due to the step difference of the base material, and the arc length becomes 6 mm. From this state, the arc length is restored by the self-control action by the external characteristics and returns to 2 mm at time t3. The time from time t2 to t3 is measured as the arc length restoration time. Measurements were made for both prior art 2 and the present invention for comparison. The result is shown in FIG. As is clear from the figure, in the conventional technique 2, the arc length restoration time is about 70 ms. On the other hand, in the present invention, the arc length restoration time was significantly shortened to about 20 ms. For this reason, the fluctuation of the arc length due to the disturbance can be quickly restored and the fluctuation width can be reduced, so that the welding quality is improved.

It is a related figure of the fusion | melting characteristic which shows the consumable electrode gas-shield arc welding method by the constant current characteristic which concerns on Embodiment 1 of this invention, and a constant current characteristic. It is a block diagram of the welding power supply which concerns on Embodiment 1 of this invention. It is a current / voltage waveform diagram of pulse arc welding. It is a block diagram of the welding power supply which concerns on Embodiment 2 of this invention. It is a figure which shows the measuring method of the arc length restoration time at the time of arc length fluctuation | variation in order to demonstrate the effect of this invention. It is a figure which shows the measurement result of the prior art performed by the measuring method of FIG. 5, and the arc length restoration time of this invention. It is a related figure of the fusion characteristic in the prior art 1, and a constant voltage characteristic. It is a related figure of the melting characteristic and the constant voltage characteristic which show the subject in the prior art 1. It is a related figure of the fusion characteristic and constant current characteristic which show the subject in prior art 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Welding wire 2 Base material 3 Arc 4 Welding torch 5 Feed roll AD Adder circuit CC1-2 Constant current characteristic CP1-2 Constant voltage characteristic EI Current error amplification circuit Ei Current error amplification signal EV Voltage error amplification circuit Ib Base current IBS Base Current setting circuit Ibs Base current setting signal ID Welding current detection circuit Id Welding voltage detection signal Ip Peak current IPS Peak current setting circuit Ips Peak current setting signal IS Current setting circuit Is Current setting signal Isc Current control setting signal Iw Welding current iw Welding current Instantaneous value Iwa Pulse period welding current average value (signal)
L1-3 Melting characteristic La Arc length MC Power supply main circuit P1-6 Operating point SB Subtraction circuit SW Switching circuit Tb Base period TBS Base period setting circuit Tbs Base period setting signal Tbsc Base period control setting signal Tf Pulse period TM Timer circuit Tm Timer Signal Tp Peak period TPS Peak period setting circuit Tps Peak period setting signal Vb Base voltage VD Welding voltage detection circuit Vd Welding voltage detection signal Vp Peak voltage VRA Welding voltage moving average calculation circuit Vra Welding voltage moving average value (signal)
Vw Welding voltage vw Welding voltage instantaneous value VWA Pulse cycle welding voltage average value calculation circuit Vwa Pulse cycle welding voltage average value (signal)
ΔV Voltage error amplification (value / signal)

Claims (2)

In the consumable electrode gas shielded arc welding method with constant current characteristics that feeds the welding wire at a predetermined speed and welds the arc by applying a predetermined welding current according to the constant current characteristics of the welding power source,
The welding voltage between the base metal and the welding wire is detected, the welding voltage detection value is moving averaged to calculate a welding voltage moving average value, and the welding voltage detection value is substantially equal to the welding voltage moving average value. A consumable electrode gas shield arc welding method with constant current characteristics, wherein the welding current value according to the constant current characteristics is changed. The consumable electrode gas shielded arc welding is consumable electrode pulse arc welding in which energization of a peak current during a peak period and energization of a base current during a base period are repeated as a pulse period, and the welding current value is a welding current for each pulse period. Average value, the welding voltage value is a welding voltage average value for each pulse period, and at least one of the peak period or the peak current or the base period or the base current is changed for each pulse period. The consumable electrode gas shielded arc welding method with constant current characteristics according to claim 1, wherein an average value of welding current is changed.

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