RU2016722C1 - Method of controlling arc welding by non-consumable electrode - Google Patents

Abstract

FIELD: welding. SUBSTANCE: actual voltage and amperage of arc in the interval of growing welding current are periodically monitored in each macropulse. Average value of deviations from standard characteristic is determined. Control signal is generated to act on electric drive for moving the burner to maximum discrepancy. Current and voltage of filling wire are measured in each step. Electrical power applied to the filling wire is controlled ensuring melting of its end at a distance from the surface of welding bath equal to two diameters of the filling wire. EFFECT: enhanced efficiency of the method. 5 dwg

Description

 The invention relates to welding, and in particular to automatic regulation and control of the electric mode of the process of electric arc welding by a deposited electrode in a protective gas environment and can find application in mechanical engineering, shipbuilding and aircraft building.

 The closest in technical essence to the invention is a method of arc welding of martensitic steels in a protective gas [1], which includes melting the base metal and supplying an additional wire, in which an additional wire is taken from a ferritic material, heated by passing current from an additional source to a solidus temperature arcless way and served in the tail of the weld pool perpendicular to its surface, while regulating by changing the distance between the electric odom and additional filler wire.

 The disadvantage of this method is the reduced quality of the weld, due to the narrow functionality in terms of controlling the arc welding process, since it does not include the operation of controlling the input power to the weld electrode and the additional wire and the operation of regulating the heating current of the additional wire in the pulsating current mode of the non-consumable electrode.

 The aim of the invention is to improve the quality of the weld and expand the functionality of the method by adjusting the heating current of the additional filler wire in the pulsating current mode of a non-consumable electrode.

 This is achieved by using a method for controlling the process of non-consumable electrode arc welding in a shielding gas medium with filler wire, in which a non-consumable electrode is installed at a predetermined distance from the parts to be welded, and the main arc is excited between the non-consumable electrode and the parts to be welded on the stand-by current, welding rated current of the electrode at a constant speed. At the same time, filler wire is fed into the main arc zone and the weld pool at a constant speed, which is heated by passing through it through an additional heating arc from a separate heating source, and in the pulsating current mode of the surfacing electrode, depending on the welding technological conditions, the filler wire parameters and the reference characteristic arc non-consumable electrode. The arc between the filler wire and the surface of the weld pool is excited, the real current-voltage characteristic of the main arc is taken at the selected parameters of the filler wire, for which the current and voltage of the non-consumable electrode are measured in the interval of the current rise in each cycle, the average deviation of the real current-voltage characteristic from the reference for all cycles is determined interval of current rise, the average value of the deviation form a control action.

 The average deviation of the real current-voltage characteristic from the reference is compensated by the control action obtained by a corresponding change in the distance between the non-consumable electrode and the surface of the weld pool. In each cycle, the current and voltage of the filler wire are measured and the electric power supplied to the filler wire is controlled by changing the current in the filler wire circuit based on the condition of guaranteed melting of the end of the filler wire at its distance from the surface of the weld pool, equal to two diameters of the filler wire.

 The reference current-voltage characteristic is determined as follows: for a given distance between the electrode and the product in each cycle, a series of successively increasing values of the electrode current is set and the real values of the current and voltage across the arc are recorded, while the reference current-voltage characteristics are recorded for the specified fixed values of the filler wire feed speed and its corresponding rated heating current, and successively increasing current values of the non-consumable electrode set to the same size as in the welding process.

 In FIG. 1 shows a functional diagram of a welding installation with an automatic control device based on a control microcomputer; in FIG. 2 - graphs of current-voltage characteristics of the welding arc for various values of the arc gap; in FIG. 3 - the method is represented schematically by timing diagrams of pulses of synchronization voltage (a), pulses of welding current (b) and time ratios of clock cycles and control cycles (g); in FIG. 4 - arc welding process on the interval of the arc current pulse of the non-consumable electrode; in FIG. 5 - the same, in the interval of a pause of the arc current of a non-consumable electrode.

 The microcomputer device for controlling the process of arc welding with a non-consumable electrode in a shielding gas environment includes a welding unit 1 that controls a microcomputer 2 (microcomputer), including a microprocessor 3, a memory unit 4, a control unit 5 for input and output information devices, a parallel interface 6, a unit 7 synchronization with the network, block 8 for the formation of tasks and coefficients and block 9 for interfacing the microcomputer 2 with the control object.

 The interface unit 9 comprises a galvanic separation unit 10, a controller unit 11, a timer unit 12, a digital output unit 13, a digital input unit 14, a digital-to-analog conversion unit 15, an analog signal switching unit 16 and an analog-to-digital conversion unit 17.

 The welding unit 1, which is the control object for the microcomputer, contains a welding head 18 with a non-consumable electrode 19, a mechanism 20 for moving the head 18 with a non-consumable electrode, an electric motor 21, a power amplifier 22, parts of the welded article 23, a current source 24 of the non-consumable electrode, shunt 25, matching converter 26 of the current signal and matching converter 27 of the arc voltage signal.

 The combination of the movement mechanism 20, the electric motor 21 and the power amplifier 22 is a positional electric drive 28 for moving the welding torch. This electric drive has an analog input 29 for setting the displacement value, which is the input of a power amplifier 22, through which the control voltage analog signal from the first output 30 of the digital-to-analog conversion unit 15 is supplied. The code output 31 of the block 13 distribution and amplification of the unlocking pulses is connected to the input 32 of the control unlock the semiconductor valves (thyristors) of the power supply 24. The outputs of the current signal converters 26 and the voltage signal 27 are connected respectively to the first 33 and second 34 analog inputs of the analog signal switching unit 16. The shunt 25 and the matching Converter 26 of the current signal form a sensor 35 current non-consumable electrode 19.

 The welding head 18 is moved relative to the welded product 23, a non-consumable electrode 19 is fixed on it, in parallel with which the filler wire 36 moves, which is wound using the feed rollers 37 of the filler wire supply mechanism 38 from the coil 39.

 The input power terminals of the welding source 24 are connected to the workshop three-phase supply network (Fig. 1). The first output terminal 40 of the main arc power source 24 is connected through a shunt 25 to the welded product 23, the second output terminal 41 is connected to the holder 42 of the non-consumable electrode 19. An electrode holder 42, a current collector 43, an insulating tube 44, a nozzle 45 are mounted through the welding head the welding zone is supplied with a protective (inert) gas. During welding, between the non-consumable electrode 19 and the article to be welded 23, the main arc 46 continuously burns, under the influence of which a bath 47 is formed on the product. The current of the non-consumable electrode 19 is closed to the article to be welded 23 through the column of the arc 46 and the active spot 48 of the arc located on the weld pool.

 The filler wire supply mechanism 38 with feed rollers 37, the electric motor 49 and the power amplifier 50 is a speed-adjustable electric filler wire supply 51, which controls the speed of its filing in the weld pool 47 according to a certain law. This electric drive has an analog input 52 for setting the speed of the electric motor 49 and filler wire, which is the analog input of the power amplifier 50; through input 52, a voltage control signal is applied to the latter. The second output 53 of the block 15 digital-to-analog conversion is connected to the analog input 52 of the job speed of the motor 49.

 The filler wire heater 54 may have various structures and characteristics. In the device under consideration, as an example, a constant or ripple current stabilizer controlled by an input analog signal is selected. The power inputs of source 54 are connected to the workshop three-phase supply network, the output power terminal 55 is connected to the product 23, the output power terminal 56 is connected to the current collector 43 via the power terminals of the shunt 57, the measuring terminals of the shunt 57 are connected to the inputs of the matching current transformer 58, the output of which is connected to the third input 59 of the block 16 switching analog signals.

 The third output 60 of the digital-to-analog conversion unit 15 is connected to the analog input 61 for setting the value of the heating current of the filler wire of the source 54. The inputs of the second matching converter 62 of the voltage signal are connected to the product 23 and the current collector 43, and the output to the fourth input 63 of the analog signal switching unit 16.

 The shunt 57 and the matching current signal converter 58 form a filler wire current sensor 64. Matching converters 26, 27, 58, 62 perform the functions of galvanic separation, amplification and normalization of the measured current signals and voltage signals.

 This device is intended to implement the proposed method for controlling the process of arc welding with a non-consumable electrode in a protective gas environment with filler wire feed. The essence of the proposed method is as follows.

 At the beginning of the welding process, a non-consumable electrode is installed at a specified distance from the parts to be welded, the main arc is excited between the non-consumable electrode and the parts to be welded at the standby current of the electrode, and then welding is performed at the rated current of the electrode, feeding a filler wire to the arc zone at a constant speed, which is heated by passing along it through an arc, the heating current from a separate source of heating of a direct current. In the pulsating current mode, the reference current-voltage characteristic of the main arc from the non-consumable electrode is set for a given constant value of the filler wire feed speed. When adjusting the welding current of a non-consumable electrode, the real dynamic current-voltage characteristic of the main arc is taken for a given constant value of the filler wire feed speed, for which the current and voltage of the non-consumable electrode are measured in the interval of current rise in each cycle, compared with the reference current-voltage characteristic, the average deviation of the real current-voltage characteristic is determined characteristics from the reference for all measures of the rise interval, form the control action, prop tional deviation of the mean value, and compensate for this influence average value of the corresponding deflection by changing the distance between the non-consumable electrode and the welded parts.

In this case, a series of synchronization pulses is generated, each of which is formed at the moment of zero transition of one of the three linear voltages of a three-phase industrial network and three of their inversions. With the help of these pulses, the entire process of automatic control of arc welding is divided into time into successive Kth cycles, each N of which make up the jth control cycle, and current and voltage of the non-consumable electrode are measured along the leading edge of each synchronization pulse at the beginning each tact of management. On each j-th cycle, a control action χ _{nej is generated} in digital form for a positional electric drive for moving the head in accordance with the ratio
χ _nej = K _epg ˙δ _nej , (1) where χ _nej is the control action for the electric drive moving the head with a non-consumable electrode;
K _epg is the proportionality coefficient, depending on the characteristics of the electric drive of the welding head;
δ _nej is the average calculated deviation for the j-th cycle of the real current-voltage characteristic from the reference.

The control action χ _{NJ is} converted from digital to analog form and the received analog voltage signal is supplied to the analog input of the electric drive 28 for moving the welding head 18 in each Kth control cycle until the cycle of the (j + 1) -th cycle in which its new one is determined value.

(U_нэк-U_этк),
(2) где U_нэк - текущее К-е значение напряжения между неплавящимся электродом и изделием из свариваемых деталей;
U_этк - текущее К-е значение напряжения эталонной вольтамперной характеристики для К-го значения тока;
m - число измерений за интервал нарастания импульса тока.The deviation of the real current-voltage characteristics from the reference (mismatch) is found by determining its average value by the formula:
δ _nej =

(U -U _{NEC ETC)}
(2) where U _nec is the current K-th voltage value between the non-consumable electrode and the workpiece from the parts to be welded;
U _etk - the current K-th voltage value of the reference current-voltage characteristics for the K-th current value;
m is the number of measurements over the interval of rise of the current pulse.

The value of the average deviation δ _{nej is} stored in the RAM cell of the memory unit 4. It may differ from the previous value δ _{ne (j-1)} calculated on the (j-1) -th control cycle. Until the calculation of the average deviation in the current jth cycle was completed, the control action in each cycle was calculated based on the deviation δ _{ne (j-1) of the} previous cycle. These values of the deviation and the control action should be changed, which is performed at the next k-th step of the current j-th cycle, which comes after the cycle at which the calculation of the deviation δ _{nej ended} .

Consider the management process with a specific example. Turning to FIG. 3, diagram b, showing a graph of the change in current i of the _non- arc. Consider the first cycle, on which the deviation δ _{nej of the} real VAA is recorded and calculated. from the reference. Let the number of this cycle j = 1.

Suppose that before the cycle with number j = 1, the proposed method was not implemented, since the pulsed current mode was not turned on and there were no current pulses. On the cycle with number j = 0, only the standby current flowed, which was established long before the end of the cycle j = 0. Since after the arc is established in each control cycle, the voltage across the arc U _nec is equal to the reference voltage U _etk for the kth value of the standby current, then the voltage mismatch in each cycle δ _nek = U _nek -U _etk will be zero. In accordance with formula (2), the calculated deviation δ _nej = δ _neo for the cycle with number j = 0 is equal to zero δ _neo = 0. The control action for the cycle j = 0 will also be equal to zero χ _nei = χ _neo = K _ep ˙ δ _neo = 0.

The specified value of the control action χ _nej = 0 after it has been calculated and generated after m zero-cycle cycles in accordance with the proposed method is converted into an analog form and fed to the analog input of the burner moving electric drive.

The control action begins to be applied to the electric drive in each control cycle, despite the fact that it is constant in magnitude and continues to be applied in each cycle until it _changes to χ _nej = χ _ne1 .

 For the case of the zero cycle under consideration, it is equal to zero, and the electric drive will not move the welding torch.

Let us return to the cycle with number j = 1, on which the current pulses begin. According to the formula of the method, during m clocks corresponding to the front of the current rise (interval T _f ), the voltage across the arc U _{nek is recorded} in each clock cycle, thereby obtaining a real VA.H. for the first cycle. It corresponds to a “reference” VA defined in advance for these welding conditions. x., i.e. a series of voltage values on the arc U _etk for the same successively increasing current values. For each of m clocks, the difference δ _nek = U _nek -U _{etk is found} , which is summed up and the resulting sum is divided by the number of measurements m, determining the deviation δ _nej = δ _ne1 in accordance with formula (2).

 Obviously, the operations of calculating the differences, summation and division take some time. Suppose that they occupy three clock cycles at the beginning of the TB interval of the peak of the current pulse (see Fig. 3, diagram e).

So, after passing (m + 3) control cycles, the calculation of the new deviation value δ _nej = δ _{ne1 has ended} . This value is taken to implement the control and replaced by the previous value δ _nej = δ _neo at the next [(m + 3) +1] th step of the jth cycle.

Next, the control action is again formed, but already for the cycle j = 1, in digital form in accordance with the formula (1) χ _nej = χ _ne1 = K _epg δ _ne1 . This effect is then converted into analog form and fed to the analog input of the burner moving electric drive.

Prior to the beat with number K = m + 3, of the first cycle, a control action χ _neo = K _ep · δ _neo was applied to the electric drive _.
After a cycle with number K = m + 3, another control action χ _ne1 = K _epg δ _ne1 is applied to the electric drive. Thus, the value of the control action was replaced by a new one, calculated on the 1st cycle. It will be supplied to the electric drive in each cycle of the first cycle (j = 1), starting from the number K = m + 3, up to the cycle of the next, second (j = 2) cycle, in which it will be calculated and replaced.

In a similar manner, the indicated sequence of actions is carried out for registering the voltage U _nek , calculating the differences δ _nek, determining the calculated deviation δ _nej , forming and issuing a control action on each control cycle.

After the control action is issued to the analog input of the electric drive of the head, the latter starts the engine to compensate for the deviation of the head from the set position. If the arc length is longer than necessary, a series of voltage values U _нек will be greater than the reference voltage U _etk , the estimated deviation δ _nej > 0, the control action χ _nej >0; in this case, the electric drive moves the burner towards approaching it to the product. And, conversely, if the arc is shorter than what U _etk requires, then U _nek will be less than U _etk , δ _nej <0, χ _nej <0, the electric drive moves in such a way as to move the burner away from the product, increase the length of the arc and, therefore, arc voltage U _nek .

As applied to the case under consideration, in the 1st cycle the maximum mismatch δ _ne1 will be obtained. Let, for example, δ _ne1 be numerically equal to 5 conv. units K _epg = 2, then χ _ne1 = K _epg˙ δ _ne1 = 2˙ 5 = 10. Starting from the cycle from the number K = m + 3 of the first cycle, this control action will begin to flow to the input of the electric drive of the head in each subsequent cycle throughout the first cycle to its end and the beginning of the second cycle to the beat number K = m + 3 inclusive. As a result, the electric drive will begin to bring the burner closer to the product and to the interval of the current front T _{f of the} second cycle, the mismatch will obviously decrease.

As a result of the removal of a real v.a.kh. in the first m clock cycles of the second cycle and subsequent calculations, another new mismatch value will be obtained. Let, for example, δ _ne2 be numerically equal to 3 arbitrary units, then χ _ne2 = 2 · 3 = 6. Therefore, in the measure with the number K = (m + 3) + 1 of the second cycle, δ _ne1 = 5 will be replaced by δ _ne2 = 3, and the control action will be replaced accordingly from χ _ne1 = 10 to χ _ne2 = 6. This value of the control action will be issued in each measure of the second cycle, starting from the number K = (m +3) + 1 to the number N and in each measure the next third cycle from number K = 1 to number K = m + 3, i.e. until the next value of the calculated deviation δ _nej = δ _{ne3 is determined} .

 The considered sequence of operations is carried out throughout the operating time of the claimed method, this leads to the fact that the calculated deviation as a result of the movement of the burner becomes zero, i.e. the burner will come to the set position. The positioning can change all the time due to various disturbing influences including filler wire feed. However, due to the application of the inventive method, the burner will always be automatically set to a predetermined position.

According to formula (1), a new value of the control action χ _{nej is calculated} , which is converted into an analog form and a new value of the analog signal is supplied to the input of the electric drive 28 in each control cycle until new values of the mean deviation and control effect are calculated.

The features of the method are as follows. After arc excitation, after the time required for the formed weld pool to reach its steady-state dimensions, filler wire 36 is fed into the region of the anode spot 48 of arc 46 with an optimal speed of V _opt and at the same time electrode 19 and filler wire 36 are moved in the direction of welding from speed V _St. (Fig. 4,5).

The filler wire is fed into the anode spot of the arc due to the fact that the greatest amount of heat from the welding arc is generated in the anode spot and in this place the filler wire receives the maximum amount of heat from the weld pool. Optimal speed V _{p. Opt.} filler wire is selected from the following considerations. When the feed rate is less than optimal, a droplet mechanism of metal transfer of the filler wire is observed, since in this case it melts in the arc volume. This reduces the productivity of the welding process.

When the feed rate is much higher than the optimum _Vpt , the filler wire does not have time to melt in the region of the anode spot of the arc, passes into the weld pool, may even bury at its bottom and bend, which leads to an excess of filler wire in the weld pool and causes non-fusion and metal inclusions, and ultimately to disruption of the welding process.

There is a maximum permissible speed V _{p max} of filler wire feeding, which is 1.2-1.5 times greater than its optimum speed, at which the wire travels a longer path in the weld pool, but does not reach its bottom due to melting, which provides additional heating of the wire . Thus, the optimal speed V _{p. Opt.} wire feed is characterized by the transition boundary of the mechanism for transferring inkjet wire to drip.

q_пк (4)
Затем находят среднее отклонение мощности подогрева как разность некоторого опорного максимального значения мощности Q_{п зад}, определяемого условиями плавления присадочной проволоки, и средней мощности за цикл Q_пj
δ_пj = Q_п.зад-Q_пj . (5)
Значение мощности Q_п.зад имеет следующий смысл. Присадочная проволока, продвигаемая роликами механизма подачи, по направлению к сварочной ванне с постоянной заданной скоростью V_п.зад, подогревается проходящим по ней током I_пj до температуры плавления
I_пj=

i_пk
(6)
Плавление проволоки происходит на ее конце, который почти касается сварочной ванны, но не доходит до нее на некоторую величину расстояния l_CD ^п (см. фиг. 4), которая может быть различной. Образующаяся на конце проволоки капля расплавленного металла отрывается от конца проволоки и под воздействием силы веса опускается в сварочную ванну. При этом в проволоке выделяется мощность Q_п, от значения которой за цикл Q_пj и зависит величина дугового промежутка от конца проволоки до поверхности сварочной ванны l_CD ^п . С увеличением мощности Q_пj величина l_CD ^пувеличивается вследствие более быстрого расплавления проволоки, с уменьшением мощности Q_пj величина l_CD ^п уменьшается.From similar considerations choose the optimal welding speed V _{St. opt.}
Simultaneously with operations to stabilize the length of the arc gap between the non-consumable electrode and the product, operations are performed to control the amount of electric power spent on heating the filler wire during one cycle. To do this, in each kth step, the current i _pc and the voltage U _{pc of the} filler wire are measured along the leading edge of the synchronization pulse and the instantaneous power q _{pc is} determined as the product of current and voltage
q _pc = i _pc ˙U _pc . (3) Next, calculate the average heating power for the j-th cycle of N cycles by the formula Q _pj =

q _pc (4)
Then find the average deviation of the heating power as the difference of some reference maximum value of power Q _{p back} , determined by the melting conditions of the filler wire, and the average power per cycle Q _pj
δ _pj = Q _p.- Q _pj . (5)
The value of power Q _p.sad has the following meaning. The filler wire, promoted by the rollers of the feed mechanism, towards the weld pool with a constant predetermined speed V _p.set , is heated by the current I _pj passing through it to the melting temperature
I _pj =

i _pk
(6)
The wire melts at its end, which almost touches the weld pool, but does not reach it by a certain distance l _CD ^p (see Fig. 4), which can be different. A drop of molten metal formed at the end of the wire is torn off from the end of the wire and lowered into the weld pool under the influence of a force of weight. In this case, the power Q _p is released in the wire, the value of which for the cycle Q _pj determines the value of the arc gap from the end of the wire to the surface of the weld pool l _CD ^p . With an increase in power Q _{pj, the} value of l _CD ^p increases due to faster melting of the wire, with a decrease in power Q _{pj, the} value of l _CD ^p decreases.

The value of power at which at a constant speed V _{p1 the} melt end of the filler wire is at a distance from the surface of the weld pool, equal to twice the diameter d _{p of the} wire, i.e.

l _CD ^p = 2 d _p . (7) is the reference set value Q _p.s. This power value is determined experimentally or by calculation.

The heating power of the wire is regulated by changing the heating current I _p as follows:
if δ _pj <0, then the wire current Ip is reduced,
if δ _pj > 0, then the wire current is increased,
if δ _pj = 0, then the current Iп is left unchanged.

For this, at each jth cycle, a control action χ _{pj is generated} in digital form for the source of heating of the filler wire in accordance with the ratio
χ _pj = K _pp ˙δ _pj , (8) where χ _pj is the control action applied to the input of the source of heating of the filler wire;
To _PP - the coefficient of proportionality, depending on the characteristics of the transmission channel and the power source for heating the filler wire;
δ _pj is the average calculated deviation for the j-th cycle of the real heating power from the reference set.

 The control action is converted from digital to analog form and the received analog voltage signal is supplied to the analog input 61 of the reference source 54 of the heating output 60 of the digital-to-analog conversion unit 15 in each k-th control cycle to the cycle current of the (j + 1) -th cycle, in which its new value will be determined.

The value of the average deviation δ _{pj is} stored in a special RAM cell of the memory unit 4, it can differ from the previous value δ _{p (j-1} ) calculated on the previous (j-1) -th control cycle. Until the end of the calculation of the average deviation of the heating power in the current j-th cycle, a control action χ _{p (j-1)} calculated from the deviation δ _{p (j-1) of the} previous cycle was issued to the input of the heating source in each cycle. These values of the deviation and the control action should be changed, which is performed at the next k-th step of the current j-th cycle, which comes after the cycle at which the calculation of the deviation δ _{pj ended} .

Then, according to formula (8), a new value χ _{pj is calculated} , which is converted into an analog form, and fed to input 61 of a job for source 54 of heating from output 60 of digital-to-analog conversion unit 15 in each kth control cycle until that next cycle (j + 1 ) th cycle in which its new value will be determined, etc.

 As a result, even in the presence of a pulsating current of the non-consumable electrode, the mechanism for transfer of the filler metal from the wire to the weld pool does not change, i.e., it stabilizes, which ensures high quality of the weld.

 The proposed technical solution allows to improve the quality of the weld and expand the technological capabilities of automatic welding by ensuring the maintenance of the length of the arc gap when welding in pulsating DC modes with filler wire by periodically taking the current-voltage characteristics of the arc in the interval of increase of the welding current in each pulse, determining the average value its deviations from the reference current-voltage characteristics in pace with the process, the formation in pace with percent SPS corresponding feedback control signal and to drive them to move the torch with an electrode to automatically achieve minimum error. The specified sequence of operations is performed automatically and synchronously with the alternating voltage of the industrial supply network without the participation of a human operator. High stability of synchronization of the control process provides increased accuracy and stability of the welding process, which improves the quality of the welded joint. The introduced operation of automatic control and regulation of current, voltage and power in accordance with the proposed method and the elimination of errors of the operator-welder reduces the complexity of the production of welded joints.

Claims (1)

 METHOD FOR CONTROLLING AN ARC WELDING PROCESS BY A NON-MELABLE ELECTRODE IN THE ENVIRONMENT OF PROTECTIVE GASES WITH THE SUPPLY WIRE SUPPLY, in which a non-consumable electrode is installed at a specified distance from the parts to be welded, an arc is welded between the non-consumable electrode and the weld is welded and welded an additional current source, characterized in that in order to improve the quality of the weld and expand the functionality, the non-melting power circuit the axis of the electrode supplies a pulsating current, initiates an arc between the filler wire and the surface of the weld pool, at each interval of increase in the pulsating current for several specific current values, measure the voltage on the arc and compare these voltages with the specified values corresponding to the same current values, calculate the average difference of voltage deviations for the current rise interval, the resulting average difference is converted into a signal, along which the arc length of the non-consumable electrode is changed, and in each cycle, the current is measured by ogreva wire and heater voltage, the instantaneous power is calculated as the product of voltage and current, calculating the average power of the heating for a few clock cycles and compared with the reference power, and received power difference is converted into a signal by which change the heating current.

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