JPH0677833B2 - Non-consumable electrode arc welding method and apparatus - Google Patents

Description

TECHNICAL FIELD The present invention relates to an arc welding method for performing arc welding using a non-consumable electrode and an arc welding apparatus used for this method.

[Prior Art] In the arc welding method using a non-consumable electrode,
As shown in the figure, an arc start current having a large peak value Ip is supplied for a predetermined energizing time Tp to start the arc, and then a predetermined welding current is supplied to perform welding.

The present applicant has previously mentioned that as a method of improving the arc start of DC TIG arc welding, the rising speed dI / dT of the arc start current waveform, the peak value Ip of the arc start current and the energization time Tp of the arc start current shown in FIG. A method (Japanese Patent Laid-Open No. 60-64766) for improving the arc start by setting a constant value is proposed.

[Problems to be Solved by the Invention] In the method proposed above, the success rate of arc start is improved by increasing the peak value Ip of the arc start current. However, the peak value Ip of the arc start current and the energization of the arc start current are increased. When the product Ip × Tp (hereinafter referred to as Ip × Tp) with the time Tp is increased, the amount of electrode consumption increases as shown in FIG. In FIG. 6, a tungsten electrode containing 2 [%] thorium with a diameter of 1.6 [mm] was used as the non-consumable electrode, and the peak value Ip = 100 [A] of the arc start current.
Then, the welding current Iw = 10 [A] and the arc start is performed 100 times for each Ip × Tp. Therefore, in order to improve the arc start and reduce the consumption of the electrode, it is necessary to increase the peak value Ip of the arc start current and shorten the energization time Tp of the arc start current.

However, when starting the arc when the electrode is cold, the tungsten electrode starts as a cold cathode, so the electrode does not warm up when the arc start current conduction time Tp is short, so the current is reduced to the value during steady welding. When this is done, the arc discharge cannot be maintained and the arc start fails. Therefore, in the conventional method, in order to increase the success rate of the arc start, it is necessary to increase the peak value Ip of the arc start current and then increase the energization time Tp of the arc start current to some extent.
It is unavoidable that Tp becomes large and the amount of electrode consumption increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-consumable electrode arc welding method and an apparatus for carrying out the method, which can keep the success rate of arc start high and reduce the electrode consumption as much as possible.

[Means for Solving the Problem] A first invention is a non-consumable electrode arc welding method for performing welding by repeating arc start and arc stop, and in the present invention, an arc is generated by the end of arc welding work. The arc rest time T ₀ from the time of extinction until the arc is generated again by arc start is measured, and as the arc rest time T ₀ becomes longer, the peak value Ip of the arc start current and the energization time Tp of the arc start current Peak value of arc start current by increasing at least one
Increase the product of Ip and arc start current energizing time Tp, Ip x Tp.

The second to fourth aspects of the invention relate to a non-consumable electrode arc welding apparatus that performs welding by repeating arc start and arc stop.

In the non-consumable electrode arc welding method according to the second aspect of the present invention, the arc generation extinction detection circuit 8 that detects the arc generation time and the arc extinction time and outputs a signal, and the arc generation extinction detection circuit 8 outputs the arc extinction signal. Arc pause time measurement circuit 1 that measures the arc pause time T ₀ from the time when the arc generation signal is output again and outputs the arc pause time signal S11
1, and a storage selection circuit 12 that sets and stores a start condition signal in advance corresponding to the length of the arc pause time T ₀ , selects an optimum value from the start condition signal, and outputs a start condition setting signal S12, The start current conduction time setting circuit 13 that outputs the start current conduction time signal S13 for a time determined by the start condition setting signal S12 from the time when the output signal of the arc generation extinction detection circuit 8 is input, and the peak value Ip of the arc start current Set the start current peak value setting circuit 14 and the output current switching circuit that turns on the arc start current while the start current energization signal S13 is being output, and switches to the welding current in the steady state when the output of the start current energization time signal S13 is stopped. It features 15 and.

In the non-consumable electrode arc welding method according to the third aspect of the invention, the arc generation extinction detection circuit 8 that detects the arc generation time and the arc extinction time and outputs a signal, and the arc generation extinction detection circuit 8 outputs the arc extinction signal. arc pause time measuring circuit 11 which measures the arc downtime T ₀ for outputting an arc pause time signal S11 until the output again arc occurrence signal from the time point in advance in correspondence to the length of the arc downtime T ₀ The start condition signal is set and stored, the optimum value is selected from the start condition signal and the start condition setting signal S12 is output, and the output signal of the arc generation extinction detection circuit 8 is input in advance. Depending on the start current conduction time setting circuit 13 that outputs the start current conduction time signal S13 for the set time and the start condition setting signal S12 output from the memory selection circuit 12. A start current peak value switching circuit 16 that selects the peak value Ip of the arc start current and switches the peak value Ip to the selected value, and energizes the arc start current while the start current energization time signal S13 is output, and then starts. An output current switching circuit 15 for switching to a volume current in a steady state when the output of the current conduction time signal S13 is stopped is provided.

Furthermore, in the non-consumable electrode arc welding method according to the fourth aspect of the invention, the arc generation extinction detection circuit 8 that detects the arc generation time and the arc extinction time and outputs a signal, and the arc generation extinction detection circuit 8 outputs the arc extinction signal. arc pause time measuring circuit 11 which measures the arc downtime T ₀ for outputting an arc pause time signal S11 until the output again arc occurrence signal from the time point in advance in correspondence to the length of the arc downtime T ₀ The start condition signal is set and stored, the optimum value is selected from the start condition signal, and the memory selection circuit 12 that outputs the start condition setting signal S12 and the output signal of the arc generation extinction detection circuit 8 are started from the time when the output signal is input. Condition setting signal S12
Start current energization time signal S13 for a time determined by
A start current energization time setting circuit 13 that outputs the output current and a peak value Ip of the arc start current is selected according to the start condition setting signal S12 output from the memory selection circuit 12, and the peak value Ip is switched to the selected value. A current peak value switching circuit 16 and an output current switching circuit 15 for energizing the arc start current while the start current energizing time signal S13 is output and switching to the welding current in the steady state when the output of the start current energizing time signal S13 is stopped. It is characterized by having.

[Operation] The arc pause time T ₀ is measured as described above, and at least one of the peak value Ip of the arc start current and the energization time Tp of the arc start current is increased or decreased according to the length of the arc pause time T ₀ . Therefore, if Ip × Tp is set to an appropriate value commensurate with the arc pause time T ₀ , Ip × Tp can be prevented from becoming unnecessarily large, so that the success rate of arc start can be kept high and the electrode consumption can be reduced. The amount can be reduced.

Hereinafter, the reason will be described together with the result of the experiment.

In general, the non-consumable electrode functions as a cold cathode in a cold state, so that arc start and arc continuity are poor. Therefore, in order to ensure a good arc startability, it is necessary to apply a large amount of heat input as early as possible to heat the cold consumable electrode and replace it with a hot cathode to maintain a stable arc. There is. Therefore, when the non-consumable electrode is cold, it is necessary to increase Ip × Tp at the start of the arc to some extent. However, when welding is frequently repeated with arc start and arc stop, the non-consumable electrode functions as a hot cathode that is warm, so even if Ip × Tp is reduced, arc startability is good. Become.

Fig. 7 shows the temperature of the electrode tip and the elapsed time from the arc rest (arc rest time T ₀ ) for DC TIG arc welding.
As shown in this figure, the temperature at the tip of the electrode exponentially decreases with the lapse of time after the arc is stopped. From this fact, high success rate of arc start as arc pause time T ₀ is short, arc pause time T ₀ becomes longer when the arc start success rate can be estimated be lower.

Therefore, in DC TIG arc welding, a tungsten electrode containing 2 [%] thorium with a diameter of 1.0 [mm] was used as a non-consumable electrode, and Ip × Tp and dI / dT of the arc start current waveform shown in Fig. 5 were constant. (Ip = 100 [A], Tp = 3 [m
s], therefore, Ip × Tp = 300 [A · ms], and the relationship between the arc pause time T ₀ and the arc start success rate when the welding current Iw is constant (= 1 [A]) is obtained. The results shown in FIG. 8 were obtained. From this result, when the arc start current waveform is constant, the success rate of arc start is high when the arc pause time T ₀ is short, but the arc start success rate is low when the arc pause time T ₀ is long. Then, it became clear that the arc start success rate hardly changed when the arc rest time T ₀ became longer to some extent.

Next, in DC TIG arc welding, a tungsten electrode containing 2 [%] thorium with a diameter of 1.0 [mm] was used as a non-consumable electrode, and the welding current Iw = 1 [A], and the arc start success rate was almost 100 [%]. When the relationship between Ip × Tp and the arc rest time T ₀ that can be obtained was obtained, the results shown in FIG. 9 were obtained. From this result, when the arc pause time T ₀ is short, the arc start can be almost 100 [%] successful even if Ip × Tp is made very small, but when the arc pause time T ₀ becomes long, Ip × Tp It turns out that if you do not increase the value, you will not be able to succeed in the arc start.

From the above, proper values of heat input to be given to the time of arc start of welding of the non-consumable electrode arc is related to the arc downtime T _0, with less heat input if the arc downtime T ₀ is shorter However, it turns out that the arc start can be surely performed. Therefore, by measuring the arc pause time T ₀ ,
Minimize the amount of electrode wear by setting the value of Ip × Tp to an appropriate value (minimum value required for successful arc start of almost 100 [%]) corresponding to the measured arc rest time T ₀ Can be

Based on the above examination results, the welding method of the present invention will be described with reference to FIG. In the same figure, the horizontal axis represents the elapsed time T of the welding operation, and the vertical axis represents the "ON" or "OFF" state of the torch switch SW and the welding current value I from above. At time T ₁ , when the torch switch SW is turned on, the arc starts. At time T ₂ , the torch switch SW is turned off and the arc is extinguished. From this time T ₂ , the arc rest time T ₀ is measured until the time T ₃ at which the arc is generated again and the welding work is started.

In the welding method of the present invention, as the arc rest time T ₀ becomes longer, at least one of the peak value Ip of the arc start current and the energization time Tp of the arc start current is increased.
Increase Ip × Tp. Organizing the welding method of the present invention,
It is as follows.

When the arc start current peak value Ip is kept at a preset substantially constant value and the arc rest time T ₀ is short and T ₀ = Ts, the arc start current conduction time Tp is set to Tp = Tps.
If the arc rest time T ₀ is increased as Tl, the arc start current energization time Tp is lengthened.

When the arc start current energizing time Tp is kept at a preset substantially constant value and the arc rest time T ₀ is short and T ₀ = Ts, the peak value Ip of the arc start current is Ip = Ips
The arc start time peak value Ip is increased when the arc rest time T ₀ is increased as Tl.

By varying the arc start current supply time of the peak value Ip and the arc start current Tp in correspondence with the arc downtime T _0, the more the arc downtime T ₀ becomes longer, increasing the Ip × Tp.

[Embodiment] FIG. 2 shows an embodiment of the non-consumable electrode arc welding apparatus according to the present invention. In the figure, reference numeral 1 is a welding power source used in a normal non-consumable electrode arc welding method. As this welding power source, an approximately constant current characteristic of a characteristic in which an output current value is determined by an output setting signal from the outside is used. Use a power supply. Reference numeral 3 is a welding torch, 4 is a non-consumable electrode, 5 is a workpiece, and 6 is an arc generated between the tip of the consumable electrode and the workpiece 5. Reference numeral 8 denotes an arc generation extinction detection circuit that detects the arc generation time and the arc extinction time and outputs a signal, such as a welding current detection circuit and an arc light detection circuit. 9
Is a welding current setting circuit for setting a normal welding current value, and supplies a welding current setting signal in a steady state to the welding power source 1.

Reference numeral 11 is an arc pause time measuring circuit for measuring the arc pause time T ₀ from the time point when the arc extinction detection circuit 8 outputs the arc extinction signal until outputting the arc occurrence signal again and outputting the arc pause time signal S11. This arc pause time measuring circuit includes a clock signal generating circuit 11a and a counter 11b.
And a latch circuit 11c. Counter 11b
Is set by the arc extinction signal output by the arc extinction detection circuit 8, and the latch circuit 11c measures the number of clock pulses generated by the clock signal generation circuit 11a until the arc generation signal arrives after the arc extinction signal is set. The count result is output to and is reset by the signal output when the latch circuit 11c confirms the input signal. The latch circuit 11c outputs the count value of the counter 11b corresponding to the arc pause time T ₀ as the arc pause time signal S11 to the storage selection circuit 12 described later.

The signal 12 is set and stored in advance corresponding to the length of the arc pause time T ₀ , and is set and stored in advance according to the length of the arc pause time signal S11 output from the arc pause time measuring circuit 11. The memory selection circuit that selects the optimum value from the starting condition signal and reads and outputs the starting condition setting signal S12, 13 is the time determined from the rise of the output signal of the arc generation extinguishing detection circuit 8 corresponding to the starting condition setting signal S12. A start current conduction time setting circuit that outputs only the start current conduction time signal S13, and a start current peak value setting circuit 14 that sets the peak value Ip of the arc start current that is conducted during the arc start current conduction period.

15 is an output current setting signal switching circuit.
Supplies the peak value setting signal S16 selected by the start current peak value switching circuit 16 described later from the start current peak value setting circuit 14 to the welding power source 1 while the start current conduction time signal S13 is being output. This circuit is switched so that the output of the welding current setting circuit 9 for instructing the welding current in the steady state is supplied when the output of the start current conduction time signal S13 is stopped.

16 is a start current peak value switch that selects the set value of the start current peak value setting circuit 14 according to the start condition setting signal S12 output from the memory selection circuit 12, obtains an appropriate value, and outputs it as the peak value setting signal S16. Reference numeral 21 is a consumable electrode diameter setting circuit, 22 is a workpiece material setting circuit, 23 is a shield gas component setting circuit, and 24 is an analog signal set by the welding current setting circuit 9 is converted into a digital signal for memory selection. This is an A / D conversion circuit supplied to the circuit 12.

Hereinafter, the operation of the welding apparatus of the present invention will be described with reference to FIGS. 2 to 4.

First, the relationship between the setting circuits of FIG. 2, the address map of FIG. 3 and the operation of the start current peak value switching circuit 16 of FIG. 4 will be described.

The arc pause time measuring circuit 11 in FIG. 2 has an arc pause time T ₀ from the time when the arc disappears until the time when the arc occurs again.
The number of clock pulses corresponding to is counted. Memory selection circuit
According to this counting result, 12 is divided into extremely short “SS”, short “S”, medium “M”, long “L”, and extremely long “LL”, for example, as shown in FIG. , Address A8 of the memory selection circuit 12
A signal of 1 or 0 is given to A10. Further, when the non-consumable electrode diameter setting circuit 21 sets the non-consumable electrode diameter, as shown in FIG. 3, the non-consumable electrode diameter is 1.6, 2.4 or 3.
Addresses A6 and A7 of the memory selection circuit 12 according to 2 [mm]
Is given a signal of 1 or 0. Similarly, when the material of the workpiece is set by the workpiece material setting circuit 22, as shown in FIG. 3, the memory selection circuit 12 is selected depending on whether the material of the workpiece is iron Fe or stainless steel SuS. Address of A5
When 0 or 1 is given to and the shield gas component setting circuit 23 sets the shield gas component, as shown in FIG. 3, the memory selection circuit 1 is selected depending on whether the shield gas component is argon gas Ar or helium gas He. 0 or 1 is given to the address A4. Further, when a welding current value is set in the welding current setting circuit 9, the set welding current value is converted into a 4-bit digital signal by the A / D conversion circuit 24 and given to the addresses A0 to A3 of the memory selection circuit 12. The memory selection circuit 12 selects a preset signal for each signal when each of the above signals is input to the addresses A0 to A10, and selects the signals D0 to D3 of the memory selection circuit 12. , The start condition setting signal S12 is output.

The start current peak value switching circuit 16 receives the start current peak value as shown in FIG. 4 according to the signals D2 and D3 of the upper 2 bits of the 4-bit signals output from the addresses D0 to D3 of the memory selection circuit 12. Any _{one of the} start current peak values I _{1 to} I ₄ set by the setting circuit 14 is selected.

In the welding apparatus of the present invention configured as described above, when the welding power source 1 supplies the output between the non-consumable electrode 4 and the workpiece 5 by the welding start switch (not shown), the arc 6 is generated and the welding is performed. An electric current flows. The arc generation extinction detection circuit 8 detects the welding current or the arc 6 and supplies an arc generation signal to the arc rest time measuring circuit 11. Counter 11
In b, the count value of the clock pulse generated between the time when the power is supplied to the welding power source 1 and the time when the arc generation signal is supplied is supplied to the memory selection circuit 12 through the latch circuit 11c. In the case of the first arc start, it is considered that the time from turning on the power to the welding power source 1 until the arc start is long, and the address A8 to the memory selection circuit 12
The signal supplied to A10 is the extreme length "LL" in FIG.
The memory selection circuit 12 selects a condition stored in advance from this condition and the signals supplied from the other circuits 21 to 24,
The start condition setting signal S12 is output from the addresses D0 to D3. By the start condition setting signal S12, the following three operations can be performed.

First operation example. When the arc start current energization time Tp is controlled by controlling only the setting time of the start current energization time setting circuit 13 in accordance with the length of the start condition setting signal S12, that is, the arc rest time T ₀ .

In this first operation example, the start current peak value switching circuit 16 is set as a fixed value or manually set in the start current peak value setting circuit 14 without being controlled by the signal from the storage selection circuit 12. One kind of set value or a plurality of set values may be manually switched. When the arc is started here, the start current peak value setting signal S16 set by the start current peak value switching circuit 16 is transmitted from the contact A of the output current switching circuit 15 to the welding power source 1
The start current is controlled by controlling the output current of the welding power source 1 to a current value determined by the start current peak value setting signal S16. On the other hand, the start current conduction time setting circuit 13 changes the contact point of the output current switching circuit 15 from A to B after the time corresponding to the lower bits D0 and D1 of the start condition setting signal S12 output from the memory selection circuit 12. Switch. By this operation, the output current of the welding power source 1 is switched from the start current value to the normal welding current set by the welding current setting circuit 9, and the arc welding work is continued. When the arc 6 is extinguished by the end of the arc welding work, the arc generation extinction detection circuit 8 outputs an arc extinction signal to the arc rest time measuring circuit 11. By inputting this arc extinction signal, the counter 11
b starts counting clock pulses. When the arc 6 is generated again to start the arc welding operation, the arc generation / disappearance detection circuit 8 supplies the arc generation signal to the arc pause time measuring circuit 11. As a result, the counter 11b stops counting clock pulses, and the latch circuit 11c supplies the memory selection circuit 12 with the number of clock pulses measured by the counter 11b. The memory selection circuit 12 reads a corresponding value from the start condition signal stored in advance in the memory selection circuit 12 according to the number of clock pulses, that is, the length of the arc pause time T ₀ , and outputs a signal from the addresses D0 to D3. The following operation is a second operation example in which the same operation as that described at the time of the first arc start is repeated. By the start condition setting signal S12 output from the memory selection circuit 12, the set time of the start current conduction time setting circuit 13 is set to a preset constant time without changing, and instead, the start condition output by the memory selection circuit 12 is set. When the start current peak value switching circuit 16 selectively switches the start current peak value set value by the setting signal S12.

In this case, circuit 16 value switching start current peak 4 by a signal with upper 2 bits D2 and D3 of the bit of the start current setting signal S12, as shown in FIG. 8, the arc downtime T ₀
Signal is selected from the start current peak value signals I _{1 to} I ₄ set in the start current peak value setting circuit 14 and supplied to the contact A of the output current setting signal switching circuit 15. The operation of other circuits other than the start current conduction time setting circuit 13 and the start current peak value switching circuit 16, such as arc generation, arc extinction, and arc generation again, is similar to the operation of.

Third operation example. The setting time of the start current conduction time setting circuit 13 by the start condition setting signal S12 output from the memory selection circuit 12 is controlled by the lower bits D0 and D1 of the start condition setting signal S12 as in the case of When the peak value switching circuit 16 is also controlled by the upper bits D2 and D3 of the start condition setting signal S12, as in the case.

The differences between the above operation examples and the above operation examples are summarized as follows.

That is, in the case of, the start condition stored in advance corresponding to the length of the arc pause time T ₀ is read from the memory selection circuit 12 as the start condition setting signal S12, and according to the start condition setting signal S12, The operation time of the start current conduction time setting circuit 13 is determined, and during this period, a start current having a preset constant peak value is conducted.

In this case, the start current peak value switching circuit 16 selects the peak value of the start current according to the start condition setting signal S12, and switches the peak value to the selected value to control energization. In this case, the energization time is a predetermined constant time.

In the case of, both the energization time Tp of the arc start current and the peak value Ip of the arc start current are controlled according to the start condition setting signal S12.

In addition, in the apparatus for carrying out the welding method of the present invention, the circuit
21 to 24 may be omitted, or these circuits may be partially replaced with other setting circuits. Also a memory selection circuit
The 12 input / output signals are not limited to those in the embodiment, and can be arbitrarily selected as long as they satisfy any one of the above-mentioned items. In addition, as a component of the circuit, a dedicated circuit for each circuit may be used, or the same operation as each dedicated circuit may be performed by a program of a microcomputer.

[Effects of the Invention] When welding is performed by the welding method and the welding apparatus of the present invention, the "arc pause time" from the time when the arc disappears due to the suspension of the arc welding work to the time when the arc occurs due to the restart of the arc welding work is measured. By controlling at least one of the arc start current energization time and the arc start current peak value according to the length, "arc rest time"
It is possible to prevent the heat input at the time of arc start from becoming excessive without being affected by the length of the arc start, and to keep the success rate of arc start high and to reduce the amount of electrode wear.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the elapsed time T (horizontal axis) and the welding current value I (vertical axis) in the embodiment of the welding method of the present invention, and FIG. 2 shows the welding method of the present invention. FIG. 3 is a block diagram showing an embodiment of a welding apparatus for carrying out the present invention, FIG. 3 is a view showing an address map of the memory selection circuit used in the embodiment of FIG. 2, and FIG. 4 is an operation of the start current peak value switching circuit of FIG. Explanatory diagram for explaining an example, FIG. 5 is a waveform diagram showing a waveform of an arc start current, and FIG. 6 is a product Ip × Tp of a peak value Ip of the arc start current and a conduction time Tp of the arc start current.
Is a graph showing the relationship between the electrode consumption and the electrode, FIG. 7 is a graph showing the relationship between the arc pause time T ₀ and the electrode tip temperature, and FIG. 8 is the arc pause time T ₀ and the arc. Fig. 9 is a diagram showing the relationship with the start success rate, and Fig. 9 shows the peak value I of the arc start current with an arc start success rate of almost 100%.
FIG. 6 is a diagram showing a relationship between a product Ip × Tp of p and an arc start current energization time Tp and an arc rest time T ₀ . 1 ... Welding power source, 3 ... Welding torch, 4 ... Non-consumable electrode, 5 ... Workpiece, 6 ... Arc, 8 ... Arc occurrence extinction detection circuit, 9 ... Welding current setting circuit , 11 ... Arc pause time measurement circuit, 12 ... Memory selection circuit, 13 ... Start current conduction time setting circuit, 14 ... Start current peak value setting circuit, 15 ... Output current setting signal switching circuit, 16 ...
… Start current peak value switching circuit, 21 …… Non-consumable electrode diameter setting circuit, 22 …… Workpiece material setting circuit, 23 …… Shield gas component setting circuit, 24 …… A / D conversion circuit.

Claims (4)

[Claims] 1. A non-consumable electrode arc welding method in which welding is repeated by repeating arc start and arc stop, and an arc pause from the time when the arc is extinguished by the end of the arc welding work until the arc is generated again by the arc start. The time T ₀ is measured, and as the arc rest time T ₀ becomes longer, at least one of the peak value Ip of the arc start current and the energization time Tp of the arc start current is increased to increase the peak value Ip of the arc start current and the arc start current. Non-consumable electrode arc welding method for increasing the product Ip × Tp with the energization time Tp of. 2. A non-consumable electrode arc welding method in which arc start and arc stop are repeated to perform welding, and an arc generation extinction detection circuit 8 which detects an arc generation point and an arc extinction point and outputs a signal, Arc pause time T ₀ from when the arc extinction detection circuit 8 outputs the arc extinction signal to when the arc extinction signal is output again
An arc pause time measuring circuit 11 for measuring and outputting an arc pause time signal S11, and a start condition signal is set and stored in advance in association with the length of the arc pause time T ₀ ,
The memory selection circuit 12 that selects the optimum value from the start condition signal and outputs the start condition setting signal S12, and the time determined by the start condition setting signal S12 from the time when the output signal of the arc generation extinction detection circuit 8 is input. Only the start current conduction time setting circuit 13 that outputs the start current conduction time signal S13 and the peak value of the arc start current
The start current peak value setting circuit 14 for setting Ip and the arc start current are supplied while the start current supply signal S13 is being output, and the start current supply time signal S1 is supplied.
A non-consumable electrode arc welding device comprising an output current switching circuit 15 that switches to a steady-state welding current when the output of 3 is stopped. 3. A non-consumable electrode arc welding method in which arc start and arc stop are repeated to perform welding, and an arc generation / annihilation detection circuit 8 for detecting an arc generation time and an arc extinction time and outputting a signal, Arc pause time T ₀ from when the arc extinction detection circuit 8 outputs the arc extinction signal to when the arc extinction signal is output again
An arc pause time measuring circuit 11 for measuring and outputting an arc pause time signal S11, and a start condition signal is set and stored in advance in association with the length of the arc pause time T ₀ ,
A storage selection circuit 12 that selects an optimum value from the start condition signal and outputs a start condition setting signal S12, and a start current energization signal for a preset time from the time when the output signal of the arc generation extinction detection circuit 8 is input. The start current conduction time setting circuit 13 that outputs S13, and the peak value Ip of the arc start current is selected according to the start condition setting signal S12 output from the memory selection circuit 12, and the peak value Ip is set to the selected value. The start current peak value switching circuit 16 to be switched and the arc start current are energized while the start current energizing time signal S13 is being output, and the welding current in the steady state is switched with the stop of the output of the pre-start distribution time signal S13. A non-consumable electrode arc welding device having an output current switching circuit 15. 4. A non-consumable electrode arc welding method in which arc start and arc stop are repeated to perform welding, and an arc generation extinction detection circuit 8 which detects a time point when the arc occurs and a time point when the arc disappears and outputs a signal. Arc pause time from when the arc generation extinction detection circuit 8 outputs the arc extinction signal to when the arc extinction signal is output again
An arc pause time measuring circuit 11 that measures T ₀ and outputs an arc pause time signal S11, and a start condition signal is set and stored in advance corresponding to the length of the arc pause time T ₀ , and the start condition signal is stored. From the input of the memory selection circuit 12 that selects the optimum value from the above and outputs the start condition setting signal S12 and the time when the output signal of the arc generation extinction detection circuit 8 is input, the start current is supplied for the time determined by the start condition setting signal S12. The start current conduction time setting circuit 13 that outputs the time signal S13, and the peak value Ip of the arc start current is selected according to the start condition setting signal S12 output from the memory selection circuit 12, and the peak value Ip is selected. The start current peak switching circuit 16 for switching to a value, and the arc start current is supplied while the start current supply time signal S13 is output, Non-consumable electrode arc welding apparatus and an output current switching circuit 15 together with the bets output stop at S13 before distribution electric time signal switched to the welding current in the steady state.