JP2000015441A - Short circuit transfer type arc welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably realize the short circuit transfer type arc welding. SOLUTION: In the short circuit transfer type arc welding which is conducted while repeating short circuiting and arcing with using a welding power source of roughly a constant voltage characteristics to adjust a time constant of a output current change by a electronic reactor circuit, an inductance value of the electronic reactor circuit of the welding power source is set to an inductance value lower than one in other times for the time of short circuiting or for the interval from a short circuit start time up to a fixed time after short circuiting completion time or from after a fixed time after a short circuiting start time up to after a fixed time after a short circuiting completion time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in consumable electrode type arc welding in which a short circuit and an arc are repeated while repeating arc, that is, a so-called short circuit transfer type arc welding.

[0002]

2. Description of the Related Art FIG. 15 shows the principle of the prior art. In FIG. 15, 1 is a welding power source, Vo is a DC voltage source, R1 is a resistor, and L1 is a reactor. 1
1 is a torch side cable, 12 is a work piece side cable, 1
4 is an arc, 15 is a workpiece, 16 is a chip, 17 is a wire, and 18 is a feed roller. Wire 17 is tip 16
And protrudes from the chip by a length Lex from the chip 16. This Lex portion is called a wire protrusion length. An arc 14 is generated from the tip of the protrusion.

FIG. 16 is a diagram for explaining the operation of the apparatus shown in FIG. 16A shows the output voltage of the welding power supply 1, FIG. 16B shows the welding voltage, and FIG. 16C shows the change in the welding current with the passage of time. The protrusion Lex in FIG. 15 is heated by the arc 14 and is also heated by Joule heat generated by the current flowing through the protrusion. By the heating, the tip of the protruding portion is melted. If the wire feeding speed is set to be slightly higher than these melting amounts, the tip of the wire 17 gradually approaches the work 15 and finally short-circuits at time t1.
When a short circuit occurs, the arc is extinguished. On the other hand, the current flowing through the wire 17 rapidly increases because the welding power supply 1 has a substantially constant voltage characteristic. After the time t1, the wire 17 is melted only by Joule heat. In addition to gravity and surface tension, an electromagnetic pinch force or the like due to a large short-circuit current acts to move the molten portion to the workpiece 15 side. At time t2, the transition of the fusion zone is completed, and a gap is formed again between the tip of the wire 17 and the workpiece 15. Immediately before the time t2, the reactor L1 stores electromagnetic energy due to a large short-circuit current, and a voltage is generated in a direction in which the decrease in the current is prevented by the electromagnetic energy.
The next arc is generated immediately after the gap is generated. When an arc is generated, the reactor L1 emits the stored electromagnetic energy as a current. During this discharge, the current decreases over time. At this time, the protruding portion of the wire 17 is heated by both the Joule heat corresponding to the current and the arc 14. Since the wire 17 is melted by this heating, the distance between the electrode tip and the workpiece 15 sharply increases immediately after the time t2, but the amount of melting decreases with a decrease in the current, and the amount of feed is smaller than the amount of melting. The tip of the wire 17 and the work 15 are short-circuited again at time t3,
The same operation as the operation after time t1 before time t3 is repeated.

[0004]

As described above, the short-circuit transfer type arc welding method has the following problems. (1) The welding current is small. For example, in the case of steel, a wire having a diameter of 0.9 mm is about 200 A or less and a diameter of 1.2 mm. Approx. 250 A or less for a single wire, approx. 30 for a 1.6 mm diameter wire
Since it is 0 A or less, it is suitable for all-position welding. (2) Shallow penetration and suitable for thin plates. (3) Less spatter and beautiful bead appearance. There are advantages such as. However, if this welding method is expanded to a larger current range and applied to high-speed welding, good short-circuit transfer arc welding cannot be achieved. For example, if the output voltage of the DC voltage source Vo is simply increased in order to increase the current, welding without a short-circuit period occurs. In addition, even if the welding speed is increased by increasing the wire feeding speed, the wire 17 is not used. It protrudes from the workpiece and does not arc.

[0005]

The problem of the conventional welding method described above is that a constant voltage characteristic is used as a welding power source, and a welding power source having the same configuration is used at the time of a short circuit and an arc. Therefore, in the present invention, the inductance value included in the output circuit of the welding power supply, the value at the time of short-circuit is lower than the value at the time of arc generation, the rising speed of the welding current at the time of short-circuit is faster than that at the time of arc, The above problem is solved by further increasing the pulse-like output current at the time of short-circuit, and high efficiency is made possible.

A first invention of the present invention is a short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed by using a welding power supply having a substantially constant voltage characteristic in which a time constant of a change in output current is adjusted by an electronic reactor circuit. The present invention proposes a short-circuit transfer type arc welding method in which an inductance value of an electronic reactor circuit of a welding power source is set to a lower inductance value from the start of a short circuit to the end of a short circuit than at other times.

A second invention relates to a short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed by using a welding power supply having a substantially constant voltage characteristic in which a time constant of a change in output current is adjusted by an electronic reactor circuit. The present invention proposes a short-circuit transfer type arc welding method in which an inductance value of an electronic reactor circuit of a welding power source is set to a lower inductance value from a start time of a short circuit to a certain time after the end of the short circuit than at other times. .

A third aspect of the present invention is a short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed using a welding power supply having a substantially constant voltage characteristic in which a time constant of a change in output current is adjusted by an electronic reactor circuit. We have proposed a short-circuit transition arc welding method in which the inductance value of the electronic reactor circuit of the welding power source is set to a lower inductance value from a certain time after the start of the short circuit to a certain time after the end of the short circuit than at other times. Things.

Further, a fourth invention of the present invention is a short-circuit transition type arc which repeats short-circuiting and arcing by using a welding power supply having a substantially constant voltage characteristic for adjusting a time constant of a change in output current by an electronic reactor circuit. In welding, the output voltage of the welding power source is set to a higher output voltage from the start of the short circuit to the end of the short circuit than at other times, and the inductance value of the electronic reactor circuit of the welding power source is set from the start of the short circuit to the end of the short circuit. Proposes a short-circuit transfer type arc welding method with a lower inductance value than at other times.

In a fifth aspect of the present invention, there is provided a short-circuit transition type arc which repeats short-circuiting and arcing by using a welding power supply having a substantially constant voltage characteristic for adjusting a time constant of a change in output current by an electronic reactor circuit. In welding, the output voltage of the welding power source is set to a higher output voltage from the start of the short circuit until a certain time after the end of the short circuit than at other times, and the inductance value of the electronic reactor circuit of the welding power source is set to the starting point of the short circuit. The present invention proposes a short-circuit transfer type arc welding method in which the inductance value is lower than that at other times from the end of a short circuit to a certain time after the end of the short circuit.

Further, a sixth invention of the present invention is a short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed by using a welding power supply having a substantially constant voltage characteristic for adjusting a time constant of a change in an output current by an electronic reactor circuit. In the above, the output voltage of the welding power source is set to a higher output voltage from a certain time after the start of the short circuit to a certain time after the end of the short circuit than at other times, and the inductance value of the electronic reactor circuit of the welding power source is changed. The present invention proposes a short-circuit transfer type arc welding method in which an inductance value is lower from a certain time after the start of a short circuit to a certain time after the end of the short circuit than at other times.

Further, a seventh invention of the present invention is the second invention,
In the third, fifth and sixth aspects of the present invention, a short-circuit transition type arc welding in which a repetition frequency of arc generation and short-circuit generation is detected, and a fixed time is determined according to a difference between the detected repetition frequency and a reference frequency. It is a method proposed.

An eighth invention of the present invention is directed to the welding power source according to the first to seventh inventions, wherein a repetition frequency of arc generation and short circuit generation is detected and a difference between the detected repetition frequency and a reference frequency is determined. The present invention proposes a short-circuit transfer type arc welding method for determining a reactor value in a period during which the inductance value of the electronic reactor circuit is reduced.

In a ninth aspect of the present invention, there is provided the welding power source according to the fourth to sixth aspects, wherein a repetition frequency of arcing and short-circuiting is detected, and a difference between the detected repetition frequency and a reference frequency is provided. The present invention proposes a short-circuit transfer type arc welding method in which the output voltage is determined during a period in which the output voltage is increased.

[0015]

FIG. 1 is a connection diagram showing an example of an apparatus for performing a welding method according to the present invention. In FIG. 1, reference numeral 10 denotes a welding power source, and DSH denotes a short-circuit detector, which determines that a short-circuit has occurred when the welding voltage has become a predetermined value or less, and outputs a short-circuit detection signal Sh. VDT is an output voltage detector;
T is an output current detector. DR11 to DR14 and DR21 to DR28 are rectifiers, C1 is a smoothing capacitor, FET1 to FET4 are field effect transistors, and T11 is a transformer for an inverter. LDC is a DC reactor, which is provided as needed, but may be omitted when all necessary inductances are covered by an electronic reactor circuit described later. CNT10
Denotes a control unit, and TS1 denotes a start command torch switch.
Otherwise, the same parts or assemblies as those of the conventional apparatus of FIG. Vof is a feedback signal of the output voltage, Iof is a feedback signal of the output current, Vw is a drive signal to the wire feeder, and Ts is a start command signal.

FIG. 2 shows the output control unit CNT10 of the apparatus shown in FIG.
It is a connection diagram which shows the specific example of. In FIG. 2, CN
T21 is a wire feed controller, ADJ21 is a wire feed speed setter, and E21 is a DC power supply. Also, CNT31
Denotes an output control unit, which comprises a pulse width control circuit PWM31, a DC power supply E31, an output voltage regulator ADJ31, an electronic reactor circuit EL31, and a comparator CMP31.
The electronic reactor EL31 includes a changeover switch S31,
It comprises coefficient units K31 and K32, a differentiating circuit DC31 and an adder ADD31.

1 and 2, the output current Iof is detected by a current detector CT, multiplied by a coefficient k1 or k2 by a coefficient unit K31 or K32 via a changeover switch S31, and then differentiated by a differentiation circuit DC31. k1 · (dI
of / dt) or k2.multidot. (dIof / dt), which is added to the output Vof of the voltage detector VDT by the adder ADD31 to form a feedback signal Vf. Adder ADD31
Vf = {Vof + k1 · (dIof / dt)} or Vf = {Vof + k2 · (dIof / dt)} is the comparator CM
At P31, it is compared with the output Vr of the output voltage regulator ADJ31, and the difference signal ΔV = Vr− ｛Vof + k1 · (dIof /
dt)｝ or ΔV = Vr− ｛Vof + k2 · (dIof /
dt)｝, the pulse width control circuit PWM31 determines the output pulse width so that the conduction time ratio is determined by the difference signal Δv, and outputs drive signals Pa and Pb for the field effect transistors FET1 to FET4 of the inverter circuit.

When the control section is configured as shown in FIG. 2, when the output current increases or decreases, the output voltage changes in accordance with the current change rate, and the control circuit acts in a direction to suppress the change in the output current. Will be. Since this phenomenon is the same as that when a reactor is inserted into the output circuit, such a control circuit is generally called an electronic reactor circuit. Here, the coefficients k1 and k2 given by the coefficient units K31 and K32 are set as k1> k2, and the changeover switch S31 is switched from (1) to (2) by the short circuit detection signal Sh when a short circuit occurs. In other words, the inductance effect exhibited by the electronic reactor becomes smaller during the short-circuiting period.

As a result, the relationship between the output voltage and current from the welding power source 10 shown in FIG. 1 changes as shown in FIG. 3A shows a welding voltage, and FIG. 3B shows a short-circuit detector D.
(C) shows a change in the SH output Sh and a change in the welding current Iof with the passage of time. In FIG. 1 to FIG. 3, when a short circuit occurs, the changeover switch S1 is switched from (1) to (2), and the inductance of the electronic reactor is switched from a large value to a small value. The current rises quickly and becomes faster than the current change of FIG. 16 in the conventional method.

Here, since the short-circuit frequency in short-circuit transition type arc welding is usually several tens Hz to several hundreds Hz, if the operating frequency of the inverter is several tens kHz,
It becomes possible to make the output change of the welding power source 10 follow the change of the welding phenomenon.

FIG. 4 shows the electronic reactor circuit EL3 of FIG.
1 shows a specific example of the differentiating circuit used in FIG. In the figure, OP31 to OP33 are operational amplifiers, C31 is a capacitor, R31 to R35 are resistors, and S31 is a changeover switch. Here, resistors R31 to R35
Are r31 to r35, respectively, and the capacitor C
Assuming that the capacitance of C31 is c31, the coefficient k of the coefficient unit K31
1 = -r33 / r32, coefficient k2 of coefficient unit K32 = -r35 /
The input signal Iof is differentiated by multiplying by the coefficient k1 or the coefficient k2 according to the state of the changeover switch S31.-(c31.r31) .k1.dIof / dt = A.k1.d
Iof / dt or − (c31 · r31) · k2 · dIof / dt = A · k2 · d
Iof / dt. (However, A = c31 · r31)

FIG. 5 shows the electronic reactor circuit EL of FIG.
Another specific example of the differentiating circuit used at 31 is shown. In this figure, OP34 is an operational amplifier, R36 is a resistor, and the other components having the same functions as those in the circuit of FIG. In the figure, resistors R32 and R36 are connected in series as a coefficient device provided on the input side of the differentiating circuit, and one of the resistors R36 is short-circuited by a changeover switch S31 when a short circuit occurs. In the case shown in the figure, k1 = -r33 / (r32 + r36) is effective as the coefficient k1 at the time of arc, and k2 = -r33 / r32 is effective as the coefficient k2 at the time of short circuit. DC3
The output of 1 is A ｛{r33 / (r32 + r36)}｝ dIof / dt at the time of arc, and A ｛{r33 / (r32)｝｝ dIof / dt at the time of short circuit, where {r33 / (r32 + r36)}> ｛. r33 / (r3
2) Since｝, a rapid increase in current can be obtained at the time of short-circuiting as in the circuit of FIG.

FIG. 6 shows the output control unit CNT10 of the apparatus shown in FIG.
It is a connection diagram which shows another specific example of No. The control unit shown in FIG. 2 is switched to the control unit shown in FIG.
A switch S41, a DC power supply E32, and an output voltage adjuster ADJ32, which operate simultaneously with the control unit 31, are added, and the other components having the same functions as those of the control unit in FIG.

In FIG. 6, an output voltage regulator ADJ32
Is set to a set value Vp higher than the set value Vb of the output voltage adjuster ADJ31 so that the output voltage becomes higher than the output voltage adjuster ADJ31. Therefore, until the short circuit occurs, the output voltage is low and the inductance of the electronic reactor circuit has a high value, and the short circuit occurs, and the changeover switches S31 and S41 switch from (1) to (2), respectively. Thus, a reactor having a high output voltage and a small inductance becomes effective, and both the rise of the welding current during the occurrence of a short circuit and the maximum value thereof become large.

On the other hand, in short-circuit transfer type arc welding, if the welding conditions are appropriate, a clean bead appearance unique to short-circuit transfer type arc welding can be obtained. This bead appearance largely depends on the short circuit frequency. Therefore, the appearance can be adjusted to a desired appearance by changing the short-circuit frequency.

When the rate of increase of the output current at the time of short-circuit is increased by increasing the short-circuit current by means of the coefficient unit K32 of FIG. 2 and the output voltage regulator ADJ32 of FIG. Accordingly, the arc time increases, and the short-circuit frequency decreases.

However, if the short-circuit frequency is adjusted according to the output current at the time of short-circuit, not only the maximum current at the time of short-circuit but also the arc voltage following this will change. In general, the average welding current does not change because the wire feed speed is not changed. Therefore, the range of adjustment of the short-circuit frequency by the output current at the time of short-circuit is narrow and not very effective.

FIG. 7 shows an example of the control unit CNT10 capable of adjusting a wider short-circuit frequency. The control unit CNT10 in FIG. 7 employs an electronic reactor EL32 in which an off-delay timer TM1 activated by a short-circuit detection signal Sh is added to the electronic reactor circuit of the control unit CNT10 shown in FIG. Is set by the time adjuster ADJ41.

FIGS. 8A and 8B are diagrams showing the output voltage and current when the control unit shown in FIG. 7 is used. FIG. 8A shows the welding voltage, FIG. 8B shows the short-circuit detection signal Sh, and FIG. The output state of the off-delay timer TM1, (d) shows changes in the welding current with the passage of time.

In FIGS. 7 and 8, the output signal of the off-delay timer TM1 changes to a high level from the rise of the short-circuit detection signal Sh, and the high level state means that the set time of the off-delay timer TM1 elapses after the short-circuit detection signal Sh disappears. Continue until you do. When a short circuit occurs and the short circuit detection signal Sh becomes a high level, the changeover switch S3
1 is switched from (1) to (2) and is switched from the coefficient unit K31 to the coefficient unit K32, and accordingly, the inductance exhibited by the electronic reactor circuit EL32 becomes a small value. When the short-circuit time is over, after the delay time of the off-delay timer TM1, the switch command signal for the switch S31 is inverted from the high level to the low level, the switch S31 is switched from (2) to (1), and the coefficient unit K31 is switched. It becomes effective again, and the inductance of the electronic reactor circuit returns to a correspondingly large value. During this delay time, since the arc has already been formed, the output current increases quickly due to the small inductance, and reaches a large value.Therefore, immediately after the arc is generated, the distance between the tip of the wire and the workpiece grows greatly. Takes a long time to short-circuit, and as a result, the short-circuit frequency decreases. As described above, since the amount of fusion during the delay time immediately after the occurrence of the arc is large, the short-circuit frequency can be largely changed with a small delay time.

FIG. 9 is a connection diagram showing still another example of the control unit CNT10. In the same figure, the time when the inductance of the electronic reactor is switched from a large value to a small value is further determined by the on-delay timer TM2 in the example of FIG.
This is an electronic reactor EL33 in which the delay is made longer than when a short circuit occurs. In FIG.
TM2 is an on-delay timer, which starts a time period after a short circuit occurs and the short circuit detection signal Sh becomes high level and the output of the off delay timer TM1 becomes high level, and after a set time of the time setting unit ADJ42, The output goes high. AND1 is an AND gate which outputs the output of the off-delay timer TM1 and the on-delay timer T
A high-level signal is output when both the output of M2 is at a high level, and a low-level signal is output when any of the input signals is at a low level. The other elements in FIG.
The same reference numerals are given to those having the same functions as those of the control unit shown in FIG.

The operation of the control unit of FIG. 9 will be described with reference to the diagram of FIG. In FIG. 10, (a) is a welding voltage,
(B) is a short-circuit detection signal Sh, (c) is an output signal of the off-delay timer TM1, and (d) is an on-delay timer TM.
2, the output signal of (e) is the output of AND gate AND1,
(F) is a diagram showing each change of the welding current over time. In FIG. 9 and FIG. 10, when a short circuit occurs, the output signal of the off-delay timer TM1 becomes high level immediately, but the on-delay timer TM
No. 2 has its output inverted to a high level after the time set by the time setting unit ADJ42. For this reason, after the occurrence of the short circuit, the AND gate AND1 goes to the high level after the time limit of the on-delay timer TM2 ends, and the changeover switch S31 is thereby switched from (1) to (2). As a result, the inductance of the electronic reactor EL33 is switched from a large value during the arc to a small value after the time limit of the on-delay timer TM2.
When the short-circuit state progresses, the transfer of the droplet and the melting of the wire progress, and the short-circuit is eliminated and an arc is generated, whereby the short-circuit detection signal Sh is inverted to a low level. Short circuit detection signal S
Even after h is inverted to low level, the off-delay timer T
Since the output of M1 outputs a high-level signal during the set time period, the output of the on-delay timer TM2 is also at high level, and the output of the AND gate AND1 that receives these outputs remains at high level. . For this reason,
The electronic reactor EL33 functions as a small inductance value from the time when the short circuit is eliminated to the time when the set time of the off-delay timer TM1 elapses.

In order to adjust the short circuit frequency, FIG.
In addition to adjusting the setting time period of the off-delay timer TM1 as described above, it can be changed by adjusting the setting time period of the on-delay timer TM2. in this case,
The effect of changing the time period is off-delay timer T
The time limit of M1 and the time limit of the on-delay timer TM2 have opposite effects. Of course, in order to adjust the short-circuit frequency, either one of the time limit of the off-delay timer TM1 and the time limit of the on-delay timer TM2 may be changed, or both may be changed.

FIG. 11 is a connection diagram showing another embodiment of the control unit CNT10, in which a target short circuit frequency is set,
The feedback control keeps the short-circuit frequency at a target value. In FIG. 11, FCN1 is a short-circuit frequency control unit, and the other elements in FIG. 11 that have the same functions as those in the example shown in FIG.

FIG. 12 shows the short circuit frequency control unit FCN of FIG.
1 is a connection diagram showing a specific example, E61 is a DC power supply, ADJ61 is a short-circuit frequency setting device, VF61 is a V / F converter that generates a pulse signal having a frequency proportional to the input voltage, PD61 is a phase comparator, LF61 is a low-pass filter, and VR61 is a voltage / resistance converter, which may be a mechanical type or a semiconductor. OP61 is an operational amplifier, and R61 is a resistor. The short-circuit frequency control unit FCN1 in FIG. 12 converts the short-circuit frequency setting signal determined by the DC power supply E61 and the short-circuit frequency setting unit ADJ61 into a signal having a frequency proportional to the set value by the V / F converter VF61, and this signal and the short-circuit detection signal Sh And a difference signal is converted into a voltage signal by a low-pass filter LF61 and output as an output voltage setting signal Vp, and a resistance value corresponding to the difference signal is output by a voltage / resistance converter VR61. The amplification factor of the operational amplifier OP61 is determined by the resistance value of the voltage / resistance converter VR61 and the resistance value of the resistor R61.
Instead of the coefficient unit K32 provided on the input side to 1.

The short-circuit frequency controller FCN1 shown in FIG. 11 constitutes a PLL circuit by this, the pulse width control circuit shown in FIG. 11, and the inverter circuit controlled by these circuits, and controls the short-circuit frequency of the welding machine to a target frequency. It is. In the case of FIG. 11, both the output voltage at the time of short circuit and the inductance value of the electronic reactor are changed by the difference between the target short circuit frequency, and the rising speed of the output current and its maximum value are changed to change the short circuit frequency. I have.

FIG. 13 is a connection diagram showing another embodiment in which a target short circuit frequency is set and the short circuit frequency is maintained at a target value by feedback control.
Reference numeral 2 denotes a short-circuit frequency control unit. The other elements in FIG. 13 have the same functions as those in the example shown in FIG.

FIG. 14 shows the short-circuit frequency control unit FCN of FIG.
12 is a connection diagram showing a specific example of the operational amplifier OP61 and the resistor R of the short-circuit frequency control unit FCN1 in FIG.
An off-delay timer TM3 is added in place of 61. The delay time of the off-delay timer TM3 is set using the resistance value output of the voltage / resistance converter VR61 as a time-limit setting resistance value. The other elements in FIG.
The same reference numerals are given to those having the same functions as those of the short-circuit frequency control unit FCN1 and description thereof is omitted.

The short-circuit frequency control unit FCN2 of FIG. 14 converts the short-circuit frequency setting signal determined by the DC power supply E61 and the short-circuit frequency setting unit ADJ61 into a V / F converter VF6.
A signal having a frequency proportional to the set value is set to 1. This signal is compared with the frequency of the short-circuit detection signal Sh by the phase comparator PD6.
1 and compares the difference signal with a low-pass filter LF.
The voltage is converted into a voltage signal by 61, the output of this signal is converted into a resistance value by a voltage / resistance converter VR61, and the time limit of the off-delay timer TM3 is determined according to the resistance value. The output signal of the off-delay timer TM3 is changed by a changeover switch S31 and a changeover switch S4.
By setting the switching command signal Sh1 to 1, the switching of the inductance of the electronic reactor EL35 from a large value to a small value and the switching of the output voltage setting signal from a low value Vb to a high value Vp, or vice versa, are short-circuited. Control is performed so that the frequency matches the target value.

Therefore, the short-circuit frequency control unit F shown in FIG.
CN2 and a pulse width control circuit PWM31 of FIG. 13 and an inverter circuit controlled by them constitute a PLL circuit, and the welding machine changes the inductance and voltage switching delay time of the electronic reactor after the start of the short circuit. Is controlled to a target frequency.

[0041]

The present invention is as described above. (1) A short-circuit transfer type arc welding with a large current, which was impossible in the past, can be stably realized. (2) All-position welding, which is a feature of short-circuit transfer type arc welding, can be performed with a large current. (2) Since short-circuit transfer type arc welding is used, welding with large current and shallow penetration can be performed, and high-speed welding of thin plates can be performed. (3) Since the adjustment of the short-circuit frequency is easy, a desired bead appearance is easily obtained. And many other effects. (4) The short-circuit transfer type arc welding method can be performed on an object to be welded other than steel.

[Brief description of the drawings]

FIG. 1 is a connection diagram showing an embodiment of an apparatus for performing a welding method according to the present invention.

FIG. 2 is a connection diagram showing a specific example of an output control unit CNT10 of the apparatus in FIG.

FIG. 3 is a diagram for explaining the operation of the apparatus of FIG. 1 when the output control unit CNT10 of FIG. 2 is used.

FIG. 4 is a connection diagram showing a specific example of an electronic reactor circuit used in the output control unit CNT10.

FIG. 5 is a connection diagram showing another specific example of an electronic reactor circuit used in the output control unit CNT10.

FIG. 6 is a connection diagram showing another specific example of the output control unit CNT10 of the apparatus of FIG.

FIG. 7 is a connection diagram showing another specific example of the output control unit CNT10 of the apparatus of FIG.

FIG. 8 is a diagram for explaining the operation of the apparatus of FIG. 1 when the output control unit CNT10 of FIG. 7 is used.

FIG. 9 is a connection diagram showing another specific example of the output control unit CNT10 of the apparatus of FIG.

FIG. 10 is a diagram for explaining the operation of the apparatus in FIG. 1 when the output control unit CNT10 in FIG. 9 is used.

FIG. 11 is a connection diagram showing another specific example of the output control unit CNT10 of the apparatus of FIG.

FIG. 12 is a connection diagram showing a specific example of the short-circuit frequency control unit FCN1 in FIG. 11;

FIG. 13 is a connection diagram showing another specific example of the output control unit CNT10 of the apparatus of FIG.

FIG. 14 is a connection diagram showing a specific example of the short-circuit frequency control unit FCN2 in FIG. 13;

FIG. 15 is a connection diagram showing the principle of the prior art.

FIG. 16 is a diagram for explaining the operation of FIG. 15;

[Explanation of symbols]

 Reference Signs List 1 welding power source 10 welding power source 11 torch side cable 12 workpiece side cable 14 arc 15 workpiece 16 chip 17 wire 18 feed roller Vo DC voltage source R1 resistor L1 reactor DR11 to DR14 rectifier DR21 to DR28 rectifier T11 Inverter transformer C2 Smoothing capacitor FET1 to FET4 Field effect transistor LDC DC reactor VDT Voltage detector CT Current detector CNT10 Control unit CNT21 Wire feed control unit CNT31 Output control unit CMP31 Comparator TS1 Start command torch switch Ts Start command signal DSH short circuit detector Sh short circuit detection signal Vof output voltage feedback signal Vw drive signal to wire feeder Vp output voltage set value Vb output voltage set value Iof welding current detection signal S 1, S41 changeover switch ADJ21 Wire feed speed setting device ADJ31, ADJ32 Output voltage adjuster ADJ41 Time setting device for off delay timer ADJ42 Time setting device for on delay timer ADJ61 Short circuit frequency setting device E21 DC power supply E31, E32 DC power supply E61 DC Power supply ADD31 Adder AND1 AND gate DC31 Differentiator K31, K32 Coefficient k1, k2 Coefficient EL1 to EL35 Electronic reactor OP43 to OP34, OP61 Operational amplifier C31 Capacitor R31 to R36, R61 Resistor FCN1, FCN2 Short circuit frequency control VF61 V / F converter PD61 Phase comparator LF61 Low-pass filter VR61 Voltage / resistance converter PWM31 Pulse width control circuit TM1, TM Off-delay timer TM2 on-delay timer

Claims (9)

[Claims] In a short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed by using a welding power supply having a substantially constant voltage characteristic in which a time constant of a change in an output current is adjusted by an electronic reactor circuit, an electronic device of the welding power supply is used. A short-circuit transition type arc welding method in which the inductance value of a static reactor circuit is set to a lower inductance value from the start of a short circuit to the end of a short circuit than at other times. 2. In short-circuit transition type arc welding in which a short circuit and an arc are repeatedly performed by using a welding power source having a substantially constant voltage characteristic in which a time constant of a change in output current is adjusted by an electronic reactor circuit, an electronic device of the welding power source is used. A short-circuit transfer arc welding method in which the inductance value of a static reactor circuit is set to a lower inductance value from the start of a short circuit to a certain time after the end of the short circuit than at other times. 3. A short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed by using a welding power supply having a substantially constant voltage characteristic in which a time constant of a change in output current is adjusted by an electronic reactor circuit. A short-circuit transfer arc welding method in which the inductance value of a static reactor circuit is set to a lower inductance value from a certain time after the start of the short circuit to a certain time after the end of the short circuit than at other times. 4. In a short-circuit transition type arc welding in which a short circuit and an arc are repeatedly performed by using a substantially constant voltage characteristic welding power source for adjusting a time constant of a change of an output current by an electronic reactor circuit, an output of the welding power source is provided. The voltage from the start of the short circuit to the end of the short circuit is set to a higher output voltage than at other times, and the inductance value of the electronic reactor circuit of the welding power source is changed from the start of the short circuit to the end of the short circuit as compared with the other times. Short-circuit transfer type arc welding method with low inductance value. 5. A short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed by using a welding power source having a substantially constant voltage characteristic in which a time constant of a change in an output current is adjusted by an electronic reactor circuit. The voltage is set to a higher output voltage than at other times during the period from the start of the short circuit to a certain time after the end of the short circuit, and the inductance value of the electronic reactor circuit of the welding power source is set to be constant after the short circuit from the start of the short circuit. A short-circuit transfer type arc welding method in which the inductance value is lower until after the time than at other times. 6. A short-circuit transition type arc welding in which a short-circuit and an arc are repeatedly performed by using a welding power supply having a substantially constant voltage characteristic in which a time constant of a change in an output current is adjusted by an electronic reactor circuit. The voltage is set to a higher output voltage than at other times during a period from a fixed time after the start of the short circuit to a fixed time after the end of the short circuit, and the inductance value of the electronic reactor circuit of the welding power source is set to the time after the start of the short circuit. A short-circuit transition type arc welding method in which an inductance value is lower than that at other times from a certain time to a certain time after the end of the short circuit. 7. The repetition frequency of the arc generation and the short-circuit generation is detected, and the predetermined time is determined according to a difference between the detected repetition frequency and a reference frequency. A short-circuit transfer type arc welding method according to claim 6. 8. An inductance value during a period in which the repetition frequency of the arc generation and the short circuit generation is detected, and the inductance value of the electronic reactor circuit of the welding power source is reduced according to a difference between the detected repetition frequency and a reference frequency. The short-circuit transfer type arc welding method according to any one of claims 1 to 7, wherein 9. A method for detecting a repetition frequency of the arc generation and the short circuit generation, and determining an output voltage in a period during which the output voltage of the welding power supply is increased according to a difference between the detected repetition frequency and a reference frequency. 7. The short-circuit transfer type arc welding method according to any one of 4 to 6.