JP3018807B2 - Consumable electrode type pulse arc welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a consumable electrode type pulse arc welding apparatus and, more particularly, to a consumable electrode type pulse arc welding apparatus for performing welding while vibrating and stirring a molten pool by periodically changing a pulse current.

[0002]

2. Description of the Related Art Conventionally, an arc discharge is formed between a consumable electrode and an object to be welded, and the arc current is controlled to a current value obtained by superimposing a pulse current of a predetermined period and a base current to perform arc welding. 2. Description of the Related Art A consumable electrode type pulse arc welding apparatus is known.

In such a pulse arc welding apparatus, when a pulse current flows between a consumable electrode and a work to be welded, a strong electromagnetic force in a direction to narrow a current path due to an interaction between a magnetic field generated by the current and the current. Power is generated,
A so-called electromagnetic pinch effect occurs. Then, when this electromagnetic pinch force acts on the tip of the consumable electrode melted by the heat of the arc discharge, the melted portion is narrowed and formed into droplets,
The droplets move to the workpiece side as molten droplets.

Therefore, in this consumable electrode type pulse arc welding apparatus, if the peak current Ip and the pulse time width Tp, the base current Ib and the base time width Tb of the arc current are appropriately set, the consumable electrode is melted for each pulse current. The droplets can be transferred to the object to be welded, and welding with a beautiful appearance can be realized.

On the other hand, in such a pulse arc welding apparatus, two types of pulse currents having different waveforms capable of transferring one droplet for each pulse are switched and output in accordance with a predetermined swell period. Thus, there is known an apparatus for improving welding quality (for example, the 47th Annual Meeting of the Japan Welding Society Conference Abstracts (pp. 116-117)).

In this apparatus, a pulse current is set to a pulse current having a large peak current Ip and a wide pulse time width Tb within a range where one pulse and one droplet can be secured, and a pulse current having a small peak current Ip. The purpose is to change the arc force applied to the workpiece over time by appropriately switching to a pulse current having a narrow time width Tb.

Here, the term "arc force" refers to an electromagnetic pressure generated toward an object to be welded due to arc discharge, and the diameter of a plasma portion due to the arc discharge increases as the consumable electrode approaches the object to be welded. As a result, the pinch force acting on the plasma portion is reduced, and a pressure gradient is generated in the plasma from the consumable electrode side toward the workpiece.

In other words, the apparatus described in the above-mentioned lecture outline stirs the molten pool in the welding process by changing the arc force in accordance with the natural oscillation period TY that can give vibration to the molten pool on the workpiece. It is intended for that purpose. When the molten pool is agitated in this manner, blowholes in the weld bead are reduced and the weld metal is finer, and the heat of the arc discharge is widely distributed throughout the molten pool, so that the entire weld bead is uniform.

For this reason, according to this apparatus, compared with the case where welding is performed by an apparatus which does not switch the pulse current waveform in accordance with the swell cycle, the welding quality is improved, such as solidification cracking is improved, and the welding quality is improved. In the case where the workpiece is a butt joint or a lap joint, it is possible to ensure a wide gap allowance at a welding location.

[0010]

In the consumable electrode type pulse arc welding apparatus, the supply amount of the consumable electrode and the consumption amount thereof need to be in an equilibrium state. For example, when the supply amount of the consumable electrode exceeds the consumable amount, the length of the arc discharge (hereinafter, referred to as the arc length) gradually decreases, and eventually the two are short-circuited to cause spatter. If the supply amount is insufficient, a desired arc current cannot be obtained as the arc length increases, and welding may not be performed with sufficient penetration.

For this reason, a consumable electrode type pulse arc welding apparatus is generally provided with a mechanism for keeping a supply amount and a consumption amount of a consumable electrode in an equilibrium state. Such a mechanism monitors the arc voltage when performing arc welding, and controls the average current Iav of the arc discharge so that the arc voltage becomes a constant value.
Is known. It is noted that the arc voltage has a value corresponding to the distance between the tip of the consumable electrode and the workpiece, and the amount of consumption of the consumable electrode has a value corresponding to the average current Iav of arc discharge.

By the way, in the conventional consumable electrode type pulse arc welding apparatus, the pulse current is set to a waveform that can realize one pulse and one droplet by setting conditions at the start of welding.
The desired average current Iav is ensured by adjusting the base time width Tb and changing the number of pulses per unit time.

For this reason, in the above-mentioned conventional apparatus, FIG.
When the waveforms of the respective pulse currents and the wave number in one swell period TI are initially set so that the two types of pulse currents are repeated at the swell period TI equal to the natural oscillation period TY as shown in FIG. With the increase and decrease of Iav, the swell period TI fluctuates as shown in FIG. 6B (adjustment example by Tb), and TY = TI is not established.

On the other hand, in order to eliminate such adverse effects, in the above-described conventional apparatus, when a configuration is adopted in which the respective times TH and TL at which two types of pulse currents are output are fixed as shown in FIG. As shown in FIG. 7B, at the time when the pulse current switches, two types of pulse current waveforms are set to 1
There is a case where they are mixed in one pulse current. A pulse current in which two types of waveforms coexist is often out of the conditions that can realize one pulse and one droplet. In this case, the droplet grows large and becomes elongated, and the consumable electrode and the workpiece are short-circuited. As a result, spatter is generated.

As described above, the conventional consumable electrode type pulse arc welding apparatus has a configuration in which the period of the pulse current is changed to maintain the arc length constant. In an actual welding process, two types of pulse currents are used. There is a problem that the effect of changing the arc force by switching of the two cannot be sufficiently secured.

The present invention has been made in view of the above points, and sets a generation period of a pulse current based on a natural oscillation period of a workpiece, and adjusts an average current of arc discharge with a pulse current waveform. Accordingly, an object of the present invention is to provide a consumable electrode type pulse arc welding apparatus capable of constantly vibrating a molten pool effectively.

[0017]

FIG. 1 shows a principle diagram of a consumable electrode type pulse arc welding apparatus which achieves the above object.

In FIG. 1, a consumable electrode M1 and a workpiece M2 which are fed at a predetermined speed are electrically connected to a power source M3. The power supply M3 generates a current set by the current waveform setting means M4 so as to form an arc discharge between the consumable electrode M1 and the workpiece M2.

The reference waveform setting means M5 generates the current waveform at a predetermined cycle and fluctuates the current waveform at a cycle longer than the cycle of occurrence and at the same cycle as the natural oscillation cycle capable of vibrating the molten pool of the workpiece M2. The pulse current to be superimposed is superimposed on a base current having a DC characteristic, and a reference waveform of arc discharge that can realize an average current to be supplied to the consumable electrode M1 is set.

The arc length detecting means M6 detects the length of the arc discharge formed between the consumable electrode M1 and the workpiece M2. The pulse current increasing / decreasing amount setting means M7 sets the increasing / decreasing amount of the pulse current to be adjusted based on the detection result of the arc length detecting means M6 in order to keep the arc discharge length constant. Then, the current waveform setting means M4 adjusts the pulse current waveform of the reference waveform set by the reference waveform setting means M5, which is set by the pulse current increase / decrease amount setting means M7 .
The current to be instructed to the power source M3 is corrected by correcting the pulse time width to be longer when the power amount is on the increasing side, and to be shorter when the power amount is on the decreasing side. Set the waveform.

[0021]

In the consumable electrode type pulse arc welding apparatus according to the present invention, the pulse current of the arc discharge formed between the consumable electrode M1 and the workpiece M2 is always set by the reference waveform setting means M5. The current waveform is generated at a predetermined generation cycle and fluctuates along the natural oscillation cycle of the workpiece M2.

When it is necessary to adjust the consumption rate of the consumable electrode M1 in order to keep the length of the arc discharge constant, the individual pulse currents generated in a predetermined generation cycle are controlled by the pulse current increase / decrease amount. The correction is made according to the increase / decrease amount set by the means M7.

Accordingly, the arc force of the arc discharge formed between the consumable electrode M1 and the workpiece M2 always has a natural oscillation period which is a cycle capable of effectively vibrating the molten pool of the workpiece M2. Fluctuates along.

[0024]

FIG. 2 is a block diagram showing the construction of an embodiment of a consumable electrode type pulse arc welding apparatus according to the present invention.
In the figure, reference numeral 1 denotes a rectifier circuit of a primary side input. The output terminal of the rectifier circuit 1 is connected to the smoothing circuit 2,
Connected to inverter circuit 3. The inverter circuit 3
Based on an output signal of a power element driving circuit 30 described later,
This is a circuit for generating a desired current.

The output terminal of the inverter circuit 3 is connected to the high frequency transformer 4. The transformer 4 is connected to a rectifier circuit 5, and the positive terminal of the output terminals of the rectifier circuit 5 is connected to a contact chip 10 via a power cable 8 having a reactor 6, and the negative terminal of the rectifier circuit 5 is connected to a power cable 9 having a shunt 7. Is connected to the workpiece 11 via the.

A wire 13 supplied from a wire reel 12 is inserted into the contact chip 10 along its central axis. The wire 13 is electrically connected to the power cable 8 in the welding torch 10 and receives a necessary power supply via the power cable 8.

The wire 13 corresponds to a consumable electrode when performing arc welding in the apparatus of the present embodiment, and is fed at a predetermined speed by a wire supply roller 14 composed of a pair of rollers.
Note that an output terminal of the motor control unit 15 is connected to the wire supply roller 14, and the feed speed of the wire 13 is determined by a command value of the motor control unit 15.

The above configuration is a configuration widely used in known consumable electrode type pulse arc welding equipment.
Hereinafter, the operation will be briefly described.

The three-phase alternating current supplied to the primary side of the consumable electrode type pulse arc welding apparatus of the present embodiment is rectified by the rectifying circuit 1 and then smoothed by the smoothing circuit 2 and then supplied to the inverter circuit 3 as a DC power supply. Is done. The inverter circuit 3
A signal having a desired cycle is output based on a drive signal supplied from a current waveform command unit 21 described later. The current output from the inverter circuit 3 is transformed by the high-frequency transformer 4 and rectified by the rectifier circuit 5 so that a DC base current and a desired pulse current are superimposed and supplied to the wire 13 and the work 11. Is done.

Accordingly, an arc discharge is generated between the wire 13 and the work 11 to generate a pulse current at a predetermined cycle. By the way, in this embodiment, the wire 1
When the above-mentioned arc discharge is formed between 3 and workpiece 11, the tip of wire 13 is heated by the heat of the arc discharge to be in a molten state.

When the arc discharge is maintained, the melting of the wire 13 proceeds, and a pinch force of the arc current acts on the melted portion, so that the tip of the wire 13 is formed into a droplet, and the wire 13 is dropped on the workpiece 11. Transition. The motor control circuit 15 rotates the wire supply motor 14 at a predetermined speed and replenishes the consumption of the wire 13 due to the transfer of the droplets.

The motor control unit 15 includes an average current setting unit 1
6 are connected. The average current setting unit 16 instructs the motor control unit 15 on the feed speed of the wire 13 necessary for welding the workpiece 11 with an appropriate joint strength, and also controls the wire fed at the feed speed. The average current to be supplied to the wire 13 in order to appropriately consume the power 13 is instructed to the frequency calculation unit 17. In this embodiment, the feed speed of the wire 13, that is, the average current to be supplied to the wire 13, is determined by the material and the wire diameter of the wire 13.

Further, in the apparatus of this embodiment, the frequency calculating section 17, the pulse timing setting section 18, the swell period setting section 19, the pulse waveform setting section 20, the swell amplitude setting section 21,
The reference waveform setting unit 22 includes the reference waveform setting unit M5.
Is equivalent to Hereinafter, the operation of these reference waveform setting means M5 equivalent parts will be described.

The frequency calculating section 17 includes an average current setting section 16
Is calculated on the basis of the average current specified by (1), the pulse current generation frequency f required to realize the average current.

The calculation method will be briefly described below. The current flowing between the wire 13 and the workpiece 11 is, for example, a peak current Ip, a pulse time width Tp, as shown in FIG.
Assuming that it is composed of the base current Ib ₀ and the base time width Tb ₀ , the average current Iav in the figure can be expressed by the following equation.

Iav = k · f (Ip · Tp + Ib ₀ · Tb ₀ ) (1) where k is a constant, and the base current Ib ₀ is the minimum necessary to maintain the arc discharge. And 50 A in the present embodiment. The base time width Tb ₀ is a value set as a minimum time during which one droplet can move for each base current flow.
When a 2 mm steel wire is used, it is set to about 0.5 msec.

Further, in order for one pulse and one droplet to be executed smoothly, a certain relationship is required between the peak current Ip and the pulse time width Tp as shown by the hatched area in FIG. It is known. This relationship can be approximately expressed as follows.

[0038] ^{Ip a · Tp = const ··· (} 2) , where the index a is a value determined experimentally, is about 1.5 to 2.0 in the present embodiment apparatus.

On the other hand, the frequency f can be expressed as follows from its definition. f = 1 / (Tp + Tb ₀ ) (3) Therefore, if the average current Iav supplied from the average current setting unit 16 is given to the above equations (1), (2), and (3),
The generation frequency f of the pulse current required to realize Iav is determined.

The apparatus of this embodiment outputs two types of pulse currents for the arc discharge: a pulse current with a relatively large arc force (large pulse) and a pulse current with a relatively small arc force (small pulse). The configuration is adopted. By changing the strength of the arc force at a predetermined cycle, the molten pool formed on the workpiece 11 in the welding process is vibrated and agitated, thereby improving the welding quality.

For this reason, the pulse timing setting unit 18 determines a large pulse and a large pulse based on the generation frequency f of the pulse current calculated by the frequency calculation unit 17 and the swell period of the pulse current set by the swell period setting unit 19. The timing for generating each of the small pulses is set.

Here, the swell period setting section 19 is a block for setting the swell period TI of the arc force, that is, the switching period between the large pulse generation period and the small pulse generation period.
In this embodiment, the undulation period TI is set to the same period as the natural oscillation period TY that can effectively vibrate the molten pool of the workpiece 11.

In response, the pulse timing setting unit 1
8 sets the timing for generating the pulse current and calculates the number of repetitions of large pulses and the number of repetitions of small pulses to be generated within one swell period in order to synchronize the fluctuation period of the arc force with the natural oscillation period TY. I do.

The pulse waveform setting section 20 is a block for setting the waveform of a large pulse and a small pulse, and the swell amplitude setting section 21 is a block for setting the magnitude of vibration of the molten pool in a resonance state. . In other words, the undulation amplitude setting unit 21 sets conditions such as the difference between the peak current of the large pulse and the peak current of the small pulse necessary for giving a desired vibration to the molten pool. Then, in the pulse waveform setting unit 20, the peak current Ip and the pulse time width Tp for each of the large pulse and the small pulse that satisfy the set conditions and the one-pulse-one droplet condition shown in FIG. 4 are set. .

The reference waveform setting unit 22 combines the pulse current generation timing set by the pulse timing setting unit 18 and the number of repetitions of each large pulse and small pulse with the pulse waveform set by the pulse waveform setting unit 20. Set the reference waveform. Therefore, the current waveform set by the reference waveform setting unit 22 can secure the average current set by the average current setting unit 16, can effectively vibrate the molten pool of the workpiece 11, and Is set as a waveform that allows one droplet to be transferred to the workpiece 11.

As described above, according to the reference waveform setting means M5 in the apparatus of the present embodiment, two types of pulse currents, both satisfying the condition of one pulse and one droplet, are switched at a predetermined cycle, and are synchronized with the natural oscillation cycle TY. It is possible to set a reference waveform indicating a change in the arc force.

In the present embodiment, the reference waveform set in this manner is not directly supplied to the wire 13, but is applied to the wire 13 by feedback control for maintaining a constant arc length. The corrected current is supplied. This is because if the arc length fluctuates greatly, poor welding such as undercut, humping or spatter will occur. Hereinafter, the feedback system of the apparatus of this embodiment will be described.

In FIG. 2, reference numeral 23 denotes a voltage detector. The voltage detector 23 detects a potential difference between the power cables 8 and 9 and supplies the detected value to a voltage comparator 24. An output terminal of an average voltage setting unit 25 for setting a predetermined voltage value to be generated between the power cables 8 and 9 is connected to the voltage comparator 24 in addition to the voltage detector 23.

When the voltage to be generated between the power cables 8 and 9 is set, the average voltage setting section 25 is used because the arc length always fluctuates before and after the wire 13 is transferred to the droplet. This is because the actually measured voltage value detected by the detector 23 is not strictly a constant value, and therefore, it is necessary to compare the actually measured voltage value and the set voltage value with the average voltage.

Here, the potential difference generated between the power cables 8 and 9 is an arc voltage generated between the tip of the wire 13 and the workpiece 11, and the value is the value of the arc voltage between the tip of the wire 13 and the workpiece 11. Shows the value corresponding to the interval. That is, in the present embodiment, the voltage detector 23 corresponds to the above-described arc length detecting means M6. Therefore, if the potential difference can be kept constant, the arc length can be kept almost constant.

Then, when the actually measured voltage value is compared with the set voltage value in the voltage comparator 24, the comparison result is supplied to the increase / decrease amount setting section 26 so as to make the two voltage values the same. The increase / decrease amount setting unit 26 corresponds to the above-described pulse current increase / decrease amount setting means M7, and is a block for setting the increase / decrease amount of the current supplied to the wire 13 based on the comparison result supplied from the voltage comparator 24. .

That is, while the current shown in FIG. 5A is supplied to the wire 13, the tip of the wire 13 approaches the workpiece 11 too much, and the actually measured voltage value is detected to be lower than the set voltage value. In such a case, it is necessary to increase the arc length by increasing the consumption speed of the wire 13. In this case, the increase / decrease amount setting unit 26 sets the increase amount of the current supplied to the wire 13.

On the other hand, if the arc length is too long and the actually measured voltage value is detected to be higher than the set voltage value, it is necessary to reduce the consumption speed of the wire 13 to reduce the arc length. In this case, the amount of the current supplied to the wire 13 to be reduced is set.

By the way, in the conventional apparatus, FIG.
When increasing or decreasing the average value of the reference current as shown in (A), the pulse time width Tp and the base time width Tb are changed. However, when the pulse time width Tp or the base time width Tb is changed, the generation period f of the pulse current fluctuates accordingly, and the swell period TI of the arc force deviates from the natural oscillation period TY as described above. There was a problem that it would.

In the apparatus of this embodiment, the increase / decrease amount setting section 26 sets only the increase / decrease amount of the pulse current among the currents supplied to the wire 13, and the increase / decrease amount corresponds to the above-mentioned current waveform setting means M4. Current waveform setting unit 27
, The reference waveform set by the reference waveform setting unit 22 is synthesized. As a result, in the device of the present embodiment, the average value of the current supplied to the wire 13 can be changed without changing the generation frequency f of the pulse current.

For this reason, the current set by the current waveform setting section 27 has a pulse time width Tp that varies with respect to the reference waveform shown in FIG. 5A (FIG. 5B) or the peak current Ip. (FIG. 5 (C)), the time TH at which large pulses repeatedly appear and the time TL at which small pulses repeatedly appear are fixed, and the generation frequency f of each pulse current does not change.

Since the pulse current after the pulse time width Tp and the peak current Ip are corrected in this way, it is required that the conditions for one pulse and one droplet are satisfied. When setting the waveform, the pulse current is set so as to satisfy the vicinity of the median of the one-pulse / one-droplet condition shown by hatching in FIG.

A current detector 28 is connected to the shunt 7 provided in the middle of the power cable 9.
The current detector 28 detects a current discharged from the wire 13 to the workpiece 11, that is, an arc current, and outputs the detected value to the current comparator 29.

The current comparator 29 controls the power element so that the current waveform set by the current waveform setting section 27 is reproduced as an arc discharge current actually formed between the wire 13 and the workpiece 11. The drive circuit 30 is driven.

As described above, according to the present embodiment, even when the average value of the current to be supplied to the wire 13 fluctuates, the cycle in which the large pulse and the small pulse are switched, that is, the arc force applied to the workpiece 11 Undulation period TI does not fluctuate, and the natural oscillation period T that can always effectively vibrate the molten pool
The same cycle as Y can be maintained. For this reason, stable welding quality can be ensured compared to conventional equipment, and not only welding of galvanized steel sheet, which has been widely performed conventionally, but also resin-coated steel sheet and resin sandwich steel sheet can be welded,
Further, application to seal welding of a sealed container or the like is also possible.

In this embodiment, two types of pulse currents, that is, a large pulse and a small pulse, both satisfy the one-pulse-one droplet condition shown in FIG. That is,
The large pulse is a combination of a relatively high peak current Ip and a relatively narrow pulse time width Tp, and the small pulse is a relatively low peak current Ip and a relatively wide pulse time width TP.
And the combination.

For this reason, the size of the droplet formed by each pulse becomes substantially uniform, and the wire 1 is divided into a period TH in which large pulses repeatedly appear and a period TL in which small pulses repeatedly appear.
No noticeable difference occurs in the wear rate of No. 3 and the arc length can be maintained at a stable length, so that good appearance and joint strength can always be maintained.

In the present embodiment, the arc force is varied by two types of pulse currents, i.e., a large pulse and a small pulse.
Any configuration that can be varied along Y is sufficient.
A configuration in which three or more types of pulse currents are combined may be employed.

[0064]

As described above, according to the present invention, the pulse current is controlled within the range that satisfies the condition of one pulse and one droplet and along the natural vibration period that can effectively vibrate the molten pool of the workpiece. The current of the arc discharge can be set so that the arc force exerted by the current fluctuates, and the average value of the current supplied to the consumable electrode can be changed without changing the generation cycle of the pulse current.

Therefore, in the consumable electrode type pulse arc welding apparatus according to the present invention, the swell cycle of the arc force exerted by the pulse current can always be maintained at the same cycle as the natural oscillation cycle, and the swell cycle deviates from the natural oscillation cycle. Compared with the conventional apparatus that may be used in some cases, the present invention has the feature that epoch-makingly good welding quality and high reliability can be secured.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a consumable electrode type pulse arc welding apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of an embodiment of a consumable electrode type pulse arc welding apparatus according to the present invention.

FIG. 3 is a diagram illustrating an example of a current waveform of arc discharge of the consumable electrode type pulse arc welding apparatus.

FIG. 4 is a diagram showing one pulse-one droplet condition of a pulse current of an arc discharge of a consumable electrode type pulse arc welding apparatus.

FIG. 5 is a diagram illustrating an example of a current waveform set in a current waveform setting unit of the device of the present embodiment.

FIG. 6 is a diagram showing an example of an arc current in a conventional consumable electrode type pulse arc welding apparatus.

FIG. 7 is a view showing another example of an arc current in a conventional consumable electrode type pulse arc welding apparatus.

[Explanation of symbols]

 M1 Consumable electrode M2, 11 Workpiece M3 Power supply M4 Current waveform setting means M5 Reference waveform setting means M6 Arc length detection means M7 Pulse current increase / decrease amount setting means 1 Rectifier circuit 2 Smoothing circuit 3 Inverter circuit 4 High frequency transformer 5 Rectifier circuit 13 Wire Reference Signs List 17 frequency calculation unit 18 pulse timing setting unit 19 undulation cycle setting unit 20 pulse waveform setting unit 21 undulation amplitude setting unit 22 reference waveform setting unit 23 voltage detector 26 increase / decrease amount setting unit 27 current waveform setting unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-206573 (JP, A) JP-A-5-23850 (JP, A) JP-A-1-254385 (JP, A) JP-A-4- 333368 (JP, A) JP-A-49-47226 (JP, A) JP-A-58-196169 (JP, A) JP-A-62-259674 (JP, A) JP-A-56-68585 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 9/09 B23K 9/173

Claims (1)

(57) [Claims] An arc discharge is formed between a consumable electrode fed at a predetermined speed and a work to be welded, in which a pulse current generated at a predetermined period and a base current having a DC characteristic are superimposed, The length of the arc discharge is detected by an arc length detecting means, and the current waveform of the arc discharge is adjusted so that the supply amount and the consumption amount of the consumable electrode are balanced and the length of the arc discharge becomes substantially constant. In a consumable electrode type pulse arc welding apparatus that performs welding by setting, within a range that satisfies a condition of one pulse and one droplet, an arc force fluctuates in synchronization with a natural oscillation period capable of vibrating a molten pool of the workpiece. As described above, at least two types of waveforms are switched at a predetermined cycle, and a reference waveform setting means for setting a reference waveform including a pulse current for securing an average current to be supplied to the consumable electrode and a predetermined base current; A pulse for setting an amount to be adjusted with respect to the pulse current waveform among the reference waveforms set by the reference waveform setting means in order to maintain a constant arc discharge length based on a detection result of the arc length detection means. a decrease amount setting means, the set reference waveform in said reference waveform setting means, the path
Without changing the generation cycle of the pulse current, the pulse time width is increased when the amount to be adjusted set by the pulse current increase / decrease amount setting means is on the increasing side, while the pulse is on the decreasing side. A consumable electrode type pulse arc welding apparatus comprising: a current waveform setting means for correcting the time width to be short .